Position measurement method, position control method, measurement method, loading method, exposure method, exoposure apparatus, and device production method
20 claims: 2 independent, 18 dependent
- 1投影光学系と液体とを介して照明光で基板を露光する露光装置であって、 前記投影光学系の複数の光学素子のうち最も像面側に配置されるレンズの近傍に設けられ、前記液体によって前記投影光学系の下に液浸領域を形成するノズル部材と、 前記液浸領域と接触可能な上面と、前記上面の凹部内に配置されるホルダと、を有し、前記基板の表面と前記上面との間に間隙が形成されるように前記凹部内で前記基板を保持するステージと、 前記ステージを移動するモータを有する駆動系と、 前記ステージの位置情報を計測する計測系と、 前記投影光学系から離れた前記基板の交換位置に配置される前記ステージの上方に前記基板を搬送する搬送系と、 前記ステージの一部を検出する検出系と、 前記計測系によって計測される位置情報に基づいて前記駆動系を制御する制御装置と、を備え、 前記検出系の検出動作において、前記検出系によって 、 前記凹部の一部 、 又は前記凹部の内周エッジとの位置関係が既知の目印が 、 検出されるとともに、前記計測系によって前記ステージの位置情報が計測され、 前記制御装置は、前記検出系の検出情報と前記計測系によって計測される前記位置情報に基づいて前記計測系の座標系での前記凹部の位置情報を取得し、前記搬送系によって前記ステージの上方に搬送される基板が前記凹部内の前記ホルダにロードされるように、前記凹部の位置情報に基づいて前記駆動系と前記搬送系との少なくとも一方を制御する露光装置。
- 2請求項1に記載の露光装置において、 前記ロードにおいて前記基板が前記ステージの上面と接触せず、かつ前記ステージの上面と前記基板の表面との間隙が所定値より小さくなるように前記基板と前記ステージとの位置関係が設定される露光装置。
- 3請求項1又は2に記載の露光装置において、 前記基板は、前記間隙が0.3mm程度以下となる、あるいは、前記間隙が実質的に一様となるように前記凹部内で保持される露光装置。
- 4請求項1~3のいずれか一項に記載の露光装置において、 前記凹部の位置情報は、前記凹部の中心位置又は形状に関する情報を含む露光装置。
- 5請求項1~4のいずれか一項に記載の露光装置において、 前記ステージは、前記基板の表面が前記上面と実質的に同一面となるように前記凹部内で前記基板を保持するとともに、前記上面によって、前記凹部内で保持される基板から外れる前記液浸領域の少なくとも一部を維持可能である露光装置。
- 6請求項1~5のいずれか一項に記載の露光装置において、 前記ステージと異なるステージを、さらに備え、 前記異なるステージは、前記駆動系によって移動されるとともに、前記計測系によって位置情報が計測され、 前記制御装置は、前記ステージと前記異なるステージとの相対移動において、前記計測系の座標系での前記ステージの外周位置情報に基づいて前記駆動系を制御する露光装置。
- 7請求項6に記載の露光装置において、 前記制御装置は、前記駆動系を制御して、前記投影光学系と対向して配置される前記ステージに対して前記異なるステージが接近するように前記ステージと前記異なるステージとを相対移動するとともに、前記液浸領域を維持しつつ前記ステージの代わりに前記異なるステージが前記投影光学系と対向して配置されるように前記投影光学系に対して前記接近したステージおよび異なるステージを相対移動する露光装置。
- 8請求項7に記載の露光装置において、 前記基板のロード動作中、前記投影光学系と対向して配置される前記異なるステージによって前記投影光学系の下に前記液浸領域が維持される露光装置。
- 9請求項6~8のいずれか一項に記載の露光装置において、 前記検出系の検出動作において、前記計測系によって前記ステージの位置情報が計測され、 前記制御装置は、前記検出系の検出情報と前記計測系の位置情報に基づいて前記外周位置情報を取得する露光装置。
- 10請求項1~9のいずれか一項に記載の露光装置を用いるリソグラフィ工程を含むことを特徴とするデバイス製造方法。
- 11投影光学系と液体とを介して照明光で基板を露光する露光方法であって、 前記投影光学系の複数の光学素子のうち最も像面側に配置されるレンズの近傍に設けられるノズル部材によって、前記投影光学系の下に前記液体で液浸領域を形成することと、 前記液浸領域と接触可能な上面と、前記上面の凹部内に配置されるホルダと、を有するステージによって、前記基板の表面と前記上面との間に間隙が形成されるように前記凹部内で前記基板を保持するために、 前記投影光学系から離れた前記基板の交換位置に配置される前記ステージの上方に搬送される前記基板を、前記ホルダにロードすることと、 前記ステージの位置情報を計測する計測系の出力に基づいて前記ステージを移動することと、を含み、 前記計測系の座標系での前記凹部の位置情報を取得するために、前記計測系によって前記ステージの位置情報を計測しつつ前記ステージの一部を検出する検出系により 、 前記凹部の一部 、 又は前記凹部の内周エッジとの位置関係が既知の目印が 、 検出され、 前記ロードにおいて、前記凹部の位置情報に基づいて前記ホルダと前記基板との位置関係が調整される露光方法。
- 12請求項11に記載の露光方法において、 前記ロードにおいて前記基板が前記ステージの上面と接触せず、かつ前記ステージの上面と前記基板の表面との間隙が0.3mm程度以下となる、あるいは、前記間隙が実質的に一様となるように前記ホルダと前記基板との位置関係が設定される露光方法。
- 13請求項11又は12に記載の露光方法において、 前記ステージは、前記基板の表面が前記上面と実質的に同一面となるように前記凹部内で前記基板を保持するとともに、前記上面によって、前記凹部内で保持される基板から外れる前記液浸領域の少なくとも一部を維持可能である露光方法。
- 14請求項11~13のいずれか一項に記載の露光方法において、 前記ステージと異なるステージは、前記計測系によって位置情報が計測されつつ移動され、 前記計測系の座標系での前記ステージの外周位置情報に基づいて前記ステージと前記異なるステージとが相対移動される露光方法。
- 15請求項14に記載の露光方法において、 前記投影光学系と対向して配置される前記ステージに対して前記異なるステージが接近するように前記ステージと前記異なるステージとが相対移動されるとともに、前記液浸領域を維持しつつ前記ステージの代わりに前記異なるステージが前記投影光学系と対向して配置されるように前記投影光学系に対して前記接近したステージおよび異なるステージが相対移動される露光方法。
- 16請求項15に記載の露光方法において、 前記基板のロード動作中、前記投影光学系と対向して配置される前記異なるステージによって前記投影光学系の下に前記液浸領域が維持される露光方法。
- 17請求項14~16のいずれか一項に記載の露光方法において、 前記外周位置情報を取得するために、前記計測系によって前記ステージの位置情報を計測しつつ前記検出系によって前記ステージの一部が検出される露光方法。
- 18請求項11~17のいずれか一項に記載の露光方法を用いるリソグラフィ工程を含むことを特徴とするデバイス製造方法。
- 19請求項1に記載の露光装置において、 前記検出系の検出動作において、前記検出系によって 、 前記凹部 の複数箇所、 又は前記目印の複数箇所が 、 検出される露光装置。
- 20請求項11に記載の露光方法において、 前記検出系により 、 前記凹部 の複数箇所、 又は前記目印の複数箇所が、検出される露光方法。
Independent claims20
194 paragraphs, as filed
0001The present invention relates to an exposure apparatus and an exposure method, and a device manufacturing method, and more particularly, an exposure apparatus and an exposure method used in a lithography process for manufacturing an electronic device such as a semiconductor element (integrated circuit or the like) or a liquid crystal display element. The present invention also relates to a device manufacturing method using an exposure method.
0002Conventionally, in a lithography process for manufacturing electronic devices such as semiconductor elements (integrated circuits, etc.) and liquid crystal display elements, an image of a mask or reticle (hereinafter collectively referred to as "reticle") pattern image is resisted via a projection optical system. A step-and-repeat reduction projection exposure apparatus that transfers to each of a plurality of shot areas on a photosensitive object (hereinafter referred to as "wafer") such as a wafer or a glass plate coated with (photosensitive agent). So-called steppers) and step-and-scan projection exposure devices (so-called scanning steppers (also called scanners)) are mainly used.
0003By the way, with the increasing integration of semiconductor elements and the miniaturization of circuit patterns, the wavelength of the exposure light (exposure wavelength) is gradually shortened and the projection optics is used in order to improve the resolution of the projection optical system provided in the projection exposure apparatus. The numerical aperture (NA) of the system is gradually increasing. On the other hand, the depth of focus is becoming narrower due to the shortening of these exposure wavelengths and the increase in NA (larger NA) of the projection optical system. It is certain that the exposure wavelength will be further shortened in the future, and if it is left as it is, the depth of focus will be too narrow, and there is a risk that the focus margin during the exposure operation will be insufficient.
0004Therefore, an exposure apparatus using an immersion method has recently attracted attention as a method of substantially shortening the exposure wavelength and increasing (widening) the depth of focus as compared with the air. As an exposure apparatus using this immersion method, an exposure apparatus is known in which the lower surface of a projection optical system and the surface of a wafer are locally filled with a liquid such as water or an organic solvent (for example,). See Patent Document 1). In the exposure apparatus described in Patent Document 1, the resolution is obtained by utilizing the fact that the wavelength of the exposure light in the liquid is 1 / n times that in the air (n is the refractive index of the liquid, which is usually about 1.2 to 1.6). The depth of focus is expanded n times compared to the projection optical system (assuming that such a projection optical system can be manufactured) in which the same resolution as that of the immersion method can be obtained by the immersion method. That is, the depth of focus can be substantially expanded n times as compared with that in the air.
0005By the way, recently, in the wafer stage of an exposure apparatus, it has been proposed to arrange a removable plate that forms a flat portion substantially flush with the wafer around the wafer held by the wafer stage. When such a removable plate is used for a wafer stage, it is necessary to know the exact position of the plate.
0006When a plate is used for the wafer stage, it is necessary to form an opening (for example, a circular opening in the case of a semiconductor wafer) for positioning the wafer in the center of the plate. For example, a perfect circle of the circular opening of the plate. If the degree is low and the shape is distorted circular or elliptical, the gap between the outer peripheral surface of the wafer and the inner peripheral surface of the opening becomes uneven, and the wafer comes into contact with the inner wall surface of the opening of the plate. There was a risk of inconvenience such as the wafer not being able to be inserted into the opening of the plate.
0007In addition, since the gap between the inner wall surface of the plate opening and the wafer is very narrow, smooth wafer loading operation becomes difficult unless the relative positions of the wafer and the plate are accurately aligned when loading the wafer. Become.
0008Further, in the case of an exposure apparatus using an immersion method, there is a possibility that the liquid may invade a portion where the gap between the inner peripheral edge of the plate opening and the outer peripheral edge of the wafer is wide.
<p num="0009"><patcit num="1"><text>International Publication No. 99/49504</text></patcit></p>
<p num="0010"> According to the first aspect of the present invention, it is an exposure apparatus that exposes a substrate with illumination light via a projection optical system and a liquid, and is arranged on the image plane side of a plurality of optical elements of the projection optical system. A nozzle member provided in the vicinity of the lens to be formed and forming a liquid immersion region under the projection optical system by the liquid, an upper surface capable of contacting the immersion region, and a holder arranged in a recess on the upper surface. A stage having and holding the substrate in the recess so that a gap is formed between the surface of the substrate and the upper surface, a drive system having a motor for moving the stage, and the stage. A measurement system that measures the position information of the above, a transfer system that conveys the substrate above the stage that is arranged at an exchange position of the substrate away from the projection optical system, and a detection system that detects a part of the stage. And a control device that controls the drive system based on the position information measured by the measurement system, and in the detection operation of the detection system, the detection system<u style="single">、</u>Part of the recess<u style="single">、</u>Alternatively, there is a mark whose positional relationship with the inner peripheral edge of the recess is known.<u style="single">、</u>At the same time as being detected, the position information of the stage is measured by the measurement system, and the control device is in the coordinate system of the measurement system based on the detection information of the detection system and the position information measured by the measurement system. The drive system and the drive system are based on the position information of the recess so that the position information of the recess is acquired and the substrate transported above the stage by the transport system is loaded into the holder in the recess. An exposure apparatus that controls at least one of the transport systems is provided.</p><p num="0011"> According to the second aspect of the present invention, there is provided a device manufacturing method comprising a lithography process using the exposure apparatus according to the first aspect.</p><p num="0012"> According to the third aspect of the present invention, it is an exposure method for exposing a substrate with illumination light via a projection optical system and a liquid, and is arranged on the image plane side of a plurality of optical elements of the projection optical system. A nozzle member provided in the vicinity of the lens to be formed forms a immersion region with the liquid under the projection optical system, and is arranged in an upper surface capable of contacting the immersion region and a recess on the upper surface. Replacing the substrate away from the projection optical system in order to hold the substrate in the recess so that a gap is formed between the surface of the substrate and the top surface by the stage having the holder. This includes loading the substrate transported above the stage arranged at the position into the holder and moving the stage based on the output of the measurement system for measuring the position information of the stage. In order to acquire the position information of the recess in the coordinate system of the measurement system, the detection system detects a part of the stage while measuring the position information of the stage by the measurement system.<u style="single">、</u>Part of the recess<u style="single">、</u>Alternatively, there is a mark whose positional relationship with the inner peripheral edge of the recess is known.<u style="single">、</u>Provided is an exposure method that is detected and in which the positional relationship between the holder and the substrate is adjusted based on the position information of the recess in the load.</p><p num="0013"> According to a fourth aspect of the present invention, there is provided a device manufacturing method comprising a lithography process using the exposure method according to the third aspect.</p>
0014<figref num="1">It is a figure which shows the schematic structure of the exposure apparatus of one Embodiment.</figref><figref num="2">It is a perspective view which shows the stage apparatus of FIG.</figref><figref num="3">It is a perspective view which shows the measurement stage of FIG.</figref><figref num="4">It is a top view which shows the wafer table.</figref><figref num="5">It is a figure for demonstrating the structure of an interferometer system.</figref><figref num="6">It is a block diagram which shows the main structure of the control system of the exposure apparatus of one Embodiment.</figref><figref num="7">It is a flowchart which shows the processing algorithm of the main control unit (internal CPU) at the time of the return operation to the reference state of a wafer table.</figref><figref num="8">It is a figure for demonstrating the start condition of the processing algorithm shown by the flowchart of FIG. 7, and is the figure which shows an example of the position of the wafer table WTB at the start.</figref><figref num="9">9 (A), 9 (B), 9 (C), and 9 (D) show the first, second, and third points when acquiring the position information of the outer peripheral edge of the liquid repellent plate. It is a figure which shows the state when the 4th measurement point is positioned in the imaging field of view of an alignment system, respectively.</figref><figref num="10">FIG. 10 (A) is a diagram showing the movement of the wafer table WTB when sequentially measuring the position information of a plurality of measurement points on the edge of the + Y side end of the liquid repellent plate, FIG. 10 (B). Is a diagram showing a state when three measurement points are set for each of the four edges of the liquid repellent plate.</figref><figref num="11">It is a flowchart (No. 1) showing the processing algorithm of the main control unit (internal CPU) during a series of processing from the replacement of the liquid-repellent plate on the wafer table to the next replacement of the liquid-repellent plate. ..</figref><figref num="12">It is a flowchart (No. 2) showing the processing algorithm of the main control unit (internal CPU) during a series of processing from the replacement of the liquid-repellent plate on the wafer table to the next replacement of the liquid-repellent plate. ..</figref><figref num="13">It is a flowchart which shows the subroutine of step 222.</figref><figref num="14">It is a flowchart which shows the subroutine of step 236.</figref><figref num="15">15 (A), 15 (B), 15 (C) and 15 (D) show the first, second, and first positions of the inner peripheral edge of the opening of the liquid repellent plate. It is a figure which shows the state when the 3rd and 4th measurement points are positioned in the imaging field of view of an alignment system, respectively.</figref><figref num="16">16 (A), 16 (B), 16 (C) and 16 (D) show the fifth, sixth and fifth positions of the inner peripheral edge of the opening of the liquid repellent plate. It is a figure which shows the state when the 7th and 8th measurement points are positioned in the imaging field of view of an alignment system, respectively.</figref><figref num="17">FIG. 17 (A) is a conceptual diagram schematically showing a state in which imaging data are acquired at eight locations on the inner peripheral edge of the opening of the liquid repellent plate, and FIG. 17 (B) is on the outer peripheral edge of the tool wafer. It is a conceptual diagram which shows typically the state which the imaging data of 8 places is acquired.</figref><figref num="18">It is a side view which shows the vicinity of the outer peripheral edge portion of a liquid repellent plate enlarged.</figref><figref num="19">19 (A) to 19 (D) are diagrams (No. 1) for explaining a modified example.</figref><figref num="20">20 (A) to 20 (C) are diagrams (No. 2) for explaining a modified example.</figref>
0015Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 17 (B).
0016FIG. 1 shows a schematic configuration of an exposure apparatus 100 of an embodiment suitable for carrying out a position measurement method, a position control method, a measurement method, a loading method, and an exposure method according to the present invention. The exposure apparatus 100 is a step-and-scan type projection exposure apparatus, that is, a so-called scanning stepper (also called a scanner). The exposure apparatus 100 includes an illumination system 10, a reticle stage RST holding the reticle R, a projection unit PU, a stage apparatus 150 having a wafer stage WST and a measurement stage MST, a control system thereof, and the like. The wafer W is placed on the wafer stage WST.
0017The illumination system 10 includes a light source and an optical integrator (fly-eye lens, rod integrator (fly-eye lens, rod integrator), as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-313250 and the corresponding US Patent Application Publication No. 2003/0025890. Includes illuminance uniforming optical system including internal reflection type integrator) or diffractive optical element), beam splitter, relay lens, variable ND filter, reticle blind, etc. (all not shown).
0018In this illumination system 10, the slit-shaped illumination region portion set by the reticle blind on the reticle R is illuminated by the illumination light (exposure light) IL with substantially uniform illuminance. Here, as the illumination light IL, ArF excimer laser light (wavelength 193 nm) is used as an example.
0019On the reticle stage RST, a reticle R on which a circuit pattern or the like is formed on the pattern surface (lower surface in FIG. 1) is fixed, for example, by vacuum suction. The reticle stage RST is aligned with the optical axis of the illumination system 10 (corresponding to the optical axis AX of the projection optical system PL described later) by the reticle stage drive system 11 (not shown in FIG. 1 but see FIG. 6) including, for example, a linear motor. It can be driven minutely in a vertical XY plane, and can be driven at a scanning speed specified in a predetermined scanning direction (here, the Y-axis direction, which is the left-right direction in the paper surface in FIG. 1).
0020The position of the reticle stage RST in the stage moving surface (including rotation around the Z axis) is determined by the reticle laser interferometer (hereinafter referred to as "reticle interferometer") 116, in the moving mirror 15 (actually, in the Y-axis direction). It is always detected with a resolution of, for example, about 0.5 to 1 nm through a Y moving mirror having orthogonal reflecting surfaces and an X moving mirror having reflecting surfaces orthogonal to the X-axis direction). The measured value of the reticle interferometer 116 is sent to the main controller 20 (not shown in FIG. 1, see FIG. 6), and the main controller 20 of the reticle stage RST is based on the measured value of the reticle interferometer 116. The position (and speed) of the reticle stage RST is calculated by calculating the positions in the X-axis direction, Y-axis direction, and θz direction (rotation direction around the Z-axis) and controlling the reticle stage drive system 11 based on the calculation results. ) Is controlled. Instead of the moving mirror 15, the end surface of the reticle stage RST may be mirror-processed to form a reflecting surface (corresponding to the reflecting surface of the moving mirror 15).
0021Above the reticle R, a pair of reticle alignment marks on the reticle R and a pair of reference marks on the corresponding measurement stage MST (hereinafter referred to as "first reference marks") via the projection optical system PL. A pair of reticle alignment detection systems RAa and RAb consisting of a TTR (Through The Reticle) alignment system using light of an exposure wavelength for simultaneously observing are provided at a predetermined distance in the X-axis direction. As these reticle alignment detection systems RAa and RAb, for example, those having the same configuration as those disclosed in Japanese Patent Application Laid-Open No. 7-176468 and the corresponding US Pat. No. 5,646,413 are used.
0022The projection unit PU is arranged below the reticle stage RST in FIG. The projection unit PU includes a lens barrel 40 and a projection optical system PL composed of a plurality of optical elements held in the lens barrel 40 in a predetermined positional relationship. As the projection optical system PL, for example, a refraction optical system composed of a plurality of lenses (lens elements) having a common optical axis AX in the Z-axis direction is used. This projection optical system PL has a predetermined projection magnification (for example, 1/4 times or 1/5 times) by telecentric on both sides, for example. Therefore, when the illumination area on the reticle R is illuminated by the illumination light IL from the illumination system 10, the illumination area IL passed through the reticle R passes through the illumination optical system PL (projection unit PU). A reduced image of the circuit pattern of the reticle R inside (a reduced image of a part of the circuit pattern) is formed in a region (exposure region) conjugate to the illumination region on the wafer W on which a resist (photosensitive agent) is coated on the surface. To.
0023In the exposure apparatus 100 of the present embodiment, since the exposure is performed by applying the immersion method, the aperture on the reticle side becomes larger as the numerical aperture NA is substantially increased. For this reason, in a refractive optics system composed of only a lens, it becomes difficult to satisfy the Petzval condition, and the projection optical system tends to be large in size. In order to avoid such an increase in the size of the projection optical system, a catadioptric system including a mirror and a lens may be used.
0024Further, in the exposure apparatus 100 of the present embodiment, since the exposure is performed by applying the immersion method, the lens located closest to the image plane side (close to the wafer W) forming a part of the projection optical system PL (hereinafter, "" A liquid supply nozzle 51A and a liquid recovery nozzle 51B, which form a part of the immersion mechanism 132, are provided in the vicinity of the tip lens) 91.
0025The liquid supply nozzle 51A is connected to the other end of a supply pipe (not shown, see FIG. 6) whose end is connected to the liquid supply device 88 (not shown in FIG. 1, see FIG. 6), and is connected to the liquid recovery nozzle 51B. Is connected to the other end of a recovery pipe (not shown, see FIG. 6), one end of which is connected to a liquid recovery device 92 (not shown in FIG. 1, see FIG. 6).
0026The liquid supply device 88 includes a liquid tank, a pressurizing pump, a temperature control device, a valve for controlling the supply / stop of the liquid to the supply pipe, and the like. As the valve, for example, it is desirable to use a flow rate control valve so that not only the supply / stop of the liquid but also the flow rate can be adjusted. The temperature control device adjusts the temperature of the liquid in the liquid tank to a temperature similar to the temperature in the chamber (not shown) in which the exposure apparatus main body is housed.
0027The tank, pressurizing pump, temperature control device, valve, etc. for supplying liquid do not have to be all provided by the exposure device 100, and at least a part of them is installed in a factory or the like where the exposure device 100 is installed. It can be replaced by equipment.
0028The liquid recovery device 92 includes a liquid tank, a suction pump, a valve for controlling the recovery / stop of the liquid via the recovery pipe, and the like. As the valve, it is desirable to use a flow rate control valve corresponding to the valve on the liquid supply device 88 side described above.
0029The tank, suction pump, valve, etc. for collecting liquid do not have to be all equipped with the exposure device 100, and at least a part of them should be replaced with equipment such as a factory where the exposure device 100 is installed. You can also.
0030As the above liquid, pure water through which ArF excimer laser light (light having a wavelength of 193 nm) is transmitted (hereinafter, simply referred to as "water" unless otherwise required) is used. Pure water has the advantage that it can be easily obtained in large quantities at semiconductor manufacturing factories and the like, and has no adverse effect on the photoresist, optical lens, etc. on the wafer.
0031The refractive index n of water with respect to ArF excimer laser light is approximately 1.44. In this water, the wavelength of the illumination light IL is shortened to 193 nm × 1 / n = about 134 nm.
0032The liquid supply device 88 and the liquid recovery device 92 each include a controller, and each controller is controlled by the main control device 20 (see FIG. 6). The controller of the liquid supply device 88 opens the valve connected to the supply pipe at a predetermined opening degree in response to an instruction from the main control device 20, and the tip lens 91 and the wafer W (or a plate described later) via the liquid supply nozzle 51A. ) And water. At this time, the controller of the liquid recovery device 92 opens the valve connected to the recovery tube at a predetermined opening degree in response to the instruction from the main control device 20, and the tip lens 91 and the wafer W via the liquid recovery nozzle 51B. Water is collected inside the liquid recovery device 92 (liquid tank) from between. At this time, in the main controller 20, the amount of water supplied from the liquid supply nozzle 51A between the tip lens 91 and the wafer W and the amount of water recovered through the liquid recovery nozzle 51B are always equal. As a result, commands are given to the controller of the liquid supply device 88 and the controller of the liquid recovery device 92. Therefore, a certain amount of water Lq (see FIG. 1) is held between the tip lens 91 and the wafer W. In this case, the water Lq held between the tip lens 91 and the wafer W is constantly replaced.
0033As is clear from the above description, the immersion mechanism 132 of the present embodiment includes the liquid supply device 88, the liquid recovery device 92, the supply pipe, the recovery pipe, the liquid supply nozzle 51A, the liquid recovery nozzle 51B, and the like. It is an immersion mechanism, and when the wafer W is exposed, an immersion region is formed in a part of the wafer W.
0034Even when the measurement stage MST is located below the projection unit PU, it is possible to fill the space between the measurement table MTB and the tip lens 91, which will be described later, in the same manner as above.
0035In the above description, for the sake of simplicity, it is assumed that one liquid supply nozzle and one liquid recovery nozzle are provided, but the present invention is not limited to this, and for example, International Publication No. 99/49504 As disclosed in No., a configuration having a large number of nozzles may be adopted. In short, any configuration may be used as long as the liquid can be supplied between the optical member (tip lens) 91 at the lowermost end of the projection optical system PL and the wafer W. For example, the immersion mechanism disclosed in International Publication No. 2004/053955 and the immersion mechanism disclosed in European Patent Application Publication No. 1420298 can also be applied to the exposure apparatus of the present embodiment.
0036The stage device 150 includes a frame caster FC, a base board 12 provided on the frame caster FC, a wafer stage WST and a measurement stage MST arranged above the upper surface of the base board 12, and these stages WST. It is equipped with an interferometer system 118 (see FIG. 6) including interferometers 16 and 18 for measuring the position of the MST, and a stage drive system 124 (see FIG. 6) for driving the stage WST and MST.
0037As can be seen from FIG. 2 showing the stage device 150 in a perspective view, the frame caster FC has a convex portion FCa protruding upward with the Y-axis direction as the longitudinal direction near the ends on one side in the X side and the other side. , FCb is formed of a substantially flat member integrally formed.
0038The base plate 12 is made of a plate-shaped member also called a surface plate, and is arranged on a region sandwiched between the convex portions FCa and FCb of the frame caster FC. The upper surface of the base plate 12 is finished with a very high flatness, and is used as a guide surface when moving the wafer stage WST and the measurement stage MST.
0039As shown in FIG. 2, the wafer stage WST is mounted on a wafer stage main body 28 arranged above the base board 12 and a Z / tilt drive mechanism (not shown) on the wafer stage main body 28. It is equipped with a wafer table WTB. The Z / tilt drive mechanism actually includes three actuators (for example, a voice coil motor) that support the wafer table WTB at three points on the wafer stage body 28, and supports the wafer table WTB in the Z-axis direction and the θx direction. (Rotation direction around the X axis) and θy direction (Rotation direction around the Y axis).
0040The wafer stage main body 28 is formed of a hollow member having a rectangular frame shape and extending in the X-axis direction. On the lower surface of the wafer stage main body 28, a plurality of, for example, four gas static pressure bearings (not shown), for example, air bearings are provided, and the wafer stage WST is several μm above the above-mentioned guide surface via these air bearings. It is non-contact supported through a degree of clearance.
0041As shown in FIG. 2, a stator 86 for the Y axis extending in the Y axis direction is arranged above the convex portion FCa of the frame caster FC. Similarly, a stator 87 for the Y axis extending in the Y axis direction is arranged above the convex portion FCb of the frame caster FC. These Y-axis stators 86 and 87 are levitated and supported by a gaseous static pressure bearing (not shown) provided on the lower surface thereof, for example, an air bearing with respect to the upper surface of the convex portions FCa and FCb via a predetermined clearance. Has been done. In the present embodiment, the stators 86 and 87 for the Y-axis are composed of magnetic pole units having a plurality of permanent magnets arranged at predetermined intervals along the Y-axis direction.
0042Inside the wafer stage main body 28, a mover 90 composed of a magnetic pole unit having a U-shaped cross section having a plurality of permanent magnets arranged at predetermined intervals along the X-axis direction is provided.
0043A stator 80 for the X-axis extending in the X-axis direction is inserted in the internal space of the mover 90. The stator 80 for the X-axis is composed of an armature unit containing a plurality of armature coils arranged at predetermined intervals along the X-axis direction. In this case, a moving magnet type X-axis linear motor that drives the wafer stage WST in the X-axis direction is configured by a mover 90 including a magnetic pole unit and an X-axis stator 80 including an armature unit. In the following, the X-axis linear motor will be referred to as an X-axis linear motor 80 by using the same reference numerals as the stator (stator for the X-axis) 80 as appropriate. As the X-axis linear motor, a moving coil type linear motor may be used instead of the moving magnet type linear motor.
0044A movable armature unit including a plurality of armature coils arranged at predetermined intervals along the Y-axis direction, for example, at the ends on one side and the other side in the longitudinal direction of the stator 80 for the X-axis. The children 82 and 83 are fixed, respectively. Each of these movers 82 and 83 is inserted from the inside into the stators 86 and 87 for the Y-axis described above, respectively. That is, in the present embodiment, two moving coil type Y-axis linear motors are configured by the movers 82 and 83 composed of armature units and the stators 86 and 87 for Y-axis composed of magnetic pole units. In the following, each of the above two Y-axis linear motors will be referred to as a Y-axis linear motor 82 and a Y-axis linear motor 83 as appropriate, using the same reference numerals as the movers 82 and 83, respectively. As the Y-axis linear motors 82 and 83, moving magnet type linear motors may be used.
0045That is, the wafer stage WST is driven in the X-axis direction by the X-axis linear motor 80, and is driven in the Y-axis direction integrally with the X-axis linear motor 80 by the pair of Y-axis linear motors 82 and 83. Further, the wafer stage WST is rotationally driven in the θz direction by slightly changing the driving force generated by the Y-axis linear motors 82 and 83 in the Y-axis direction.
0046As shown in the plan view of FIG. 4, the wafer table WTB has a substantially square shape in a plan view, and a pitcher type wafer holder WH and a plate holder PH for holding the wafer W are provided on the upper surface thereof. Has been done.
0047As shown in FIG. 4, the wafer holder WH has a plurality of first pins 32,32, ......, which are provided at predetermined intervals in a circular region having a predetermined area in the center of the upper surface of the wafer table WTB. The distances from the first rim portion 30 formed of the annular convex portion surrounding the circular region in which the first pins 32, 32, ... Are arranged and the center (holder center) of the circular region are approximately equal. It is equipped with three cylindrical second rims 35A, 35B, 35C, etc., which are projected at the positions of each apex of an equilateral triangle. The tip of each first pin 32 and the upper end surfaces of the first rim portion 30, the second rim portion 35A, 35B, and 35C are set to substantially the same height.
0048Circular through holes 39 in a plan view are formed on the inner circumferences of the second rim portions 35A, 35B, and 35C, and each of the through holes 39 has a cylindrical shape in the vertical direction (paper surface in FIG. 4). Vertically moving pins (center-up) 34a, 34b, and 34c that can move in the orthogonal direction are provided, respectively. These three center-ups 34a to 34c are in the vertical direction (Z-axis direction, which is the direction orthogonal to the paper surface in FIG. 4) via a vertical movement mechanism (not shown) that forms a part of the stage drive system 124 (see FIG. 6). At the same time, it is moved up and down (up and down) by the same amount. When loading and unloading the wafer, the center-ups 34a to 34c are driven by the vertical movement mechanism, so that the center-ups 34a to 34c support the wafer W from below and move the wafer W up and down in that state. be able to.
0049As shown in FIG. 4, a plurality of exhaust ports 36 radiate (approximately 120 °) from the center (holder center) of the circular region in the circular region surrounded by the first rim portion 30 on the upper surface of the wafer table WTB. It is formed at predetermined intervals (in the direction of three radial lines having an interval between the central angles of). These exhaust ports 36 are formed at positions that do not interfere with the first pin 32. Each exhaust port 36 is connected to the exhaust passages 38A, 38B, 38C formed inside the wafer table WTB via the pipes directly below them, and these exhaust passages 38A, 38B, 38C are connected to the vacuum exhaust pipe 41a, respectively. It is connected to the first vacuum exhaust mechanism 44 (see FIG. 6) via 41b and 41c, respectively.
0050In the present embodiment, when the wafer W is loaded on the wafer holder WH of the wafer table WTB and the vacuum exhaust operation is started by the main controller 20 via the first vacuum exhaust mechanism 44, the wafer W and the first rim are started. The inside of the space surrounded by the part 30 and the three second rim parts 35A, 35B, and 35C is in a negative pressure state, and the wafer W has a plurality of first pin 32, the first rim part 30, and the three second rim parts 35A. , 35B, 35C and are adsorbed and held.
0051A third rim portion 45 formed of an annular protrusion concentric with the first rim portion 30 is projected outside the first rim portion 30 on the upper surface of the wafer table WTB. On the outside of the third rim portion 45, a recess 49 is formed in which the inside is partitioned by the third rim portion 45 and the outside is surrounded by the outer partition wall 48 of the wafer table WTB. A plurality of second pins 53 having the height of the tip thereof at substantially the same height as the third rim portion 45 and the outer partition wall 48 are provided on the inner bottom surface of the recess 49 at predetermined intervals. In this case, the heights of the upper end surfaces of the third rim portion 45 and the outer partition wall 48 are set to be slightly lower than those of the first rim portion 30. An approximately square liquid repellent plate (eg, a water repellent plate) 50 having a circular opening 50a in the center on the third rim portion 45, the outer partition wall 48, and the plurality of second pins 53 thus constructed. Is detachably mounted. The liquid-repellent plate 50 is mounted on the wafer table WTB with its outer peripheral surface protruding slightly outward from the outer surface of the outer partition wall 48 of the wafer table WTB. That is, a pin chuck type plate holder PH that holds the liquid repellent plate 50 is configured including the third rim portion 45 on the upper surface of the wafer table WTB, the outer partition wall 48, and the plurality of second pins 53.
0052Here, similarly to the wafer holder WH described above, a plurality of regions having a plurality of second pins 53 partitioned by the third rim portion 45 and the outer partition wall 48, which form a part of the plate holder PH, are also provided. Exhaust ports (not shown) are formed at predetermined intervals, and each exhaust port is connected to an exhaust path (not shown) formed inside the wafer table WTB via a pipe directly under them, and these exhausts are exhausted. The roads are connected to the second vacuum exhaust mechanism 56 shown in FIG. 6 via vacuum exhaust pipes (not shown).
0053In the present embodiment, the inside of the space (internal space of the recess 49) surrounded by the liquid repellent plate 50, the third rim portion 45, and the external partition wall 48 by the main controller 20 via the second vacuum exhaust mechanism 56 described above. Is vacuum sucked, and the liquid repellent plate 50 is sucked and held by the plate holder PH. Here, for example, in order to facilitate the removal of the liquid repellent plate 50, a vertical movement pin similar to the center-up 34a to 34c described above is provided inside the space, and the drive mechanism of the vertical movement pin is mainly controlled. The device 20 may control it.
0054In the present embodiment, the upper surface of the liquid repellent plate 50 adsorbed and held by the above-mentioned plate holder PH and the surface of the wafer W adsorbed and held by the wafer holder WH are substantially flush with each other (see FIG. 1). The height of each part constituting the wafer holder WH and the plate holder PH is set. Further, in the state of being held by the plate holder PH, the inner peripheral edge of the opening 50a of the liquid repellent plate 50 substantially coincides with the inner peripheral wall of the third rim portion 45. That is, in the present embodiment, a recess 140 for loading the wafer W is formed inside the inner wall surface of the third rim portion 45 and the opening 50a of the liquid repellent plate 50, and the wafer holder WH is provided in the recess 140. Has been done. Further, the shape and size of the opening 50a are set so that the clearance between the outer peripheral edge of the wafer W and the inner peripheral edge of the opening 50a of the liquid repellent plate 50 is, for example, about 0.1 to 0.4 mm. .. Further, when the wafer W is held by the wafer holder WH, an apparently fully flat surface is formed on the upper surface of the wafer table WTB.
0055The wafer table WTB is formed of a material having a low thermal expansion coefficient, for example, a material having a certain degree of elasticity such as ceramics, and the first rim portion is formed by etching the surface of the material such as ceramics having a substantially square shape as a whole. 30, the second rim portion 35A, 35B, 35C, the third rim portion 45, and the plurality of first pin 32 and the plurality of second pins 53 are integrally formed.
0056The surface of the liquid-repellent plate 50 is subjected to a liquid-repellent treatment using a fluorine-based material or the like (here, a water-repellent treatment such as a water-repellent coat) to form a liquid-repellent surface (water-repellent surface). The liquid-repellent (water-repellent) surface of the liquid-repellent plate 50 is generally vulnerable to light in the far-ultraviolet region or vacuum ultraviolet region, and the liquid-repellent (water-repellent) performance deteriorates due to irradiation with exposure light (illumination light) IL. Further, since there is a possibility that liquid adhesion marks (water marks, etc.) may be formed on the upper surface of the liquid repellent plate 50, the liquid repellent plate 50 can be easily attached / detached (replaced). The liquid repellent plate 50 can be held not only by the vacuum adsorption method but also by another method such as an electrostatic adsorption method.
0057Further, a resist (photosensitive agent) is applied to the surface of the wafer W. In the present embodiment, as an example, a photosensitizer for ArF excimer laser having liquid repellency (water repellency, contact angle 80 ° to 85 °) is used. Of course, a material for forming a top coat layer having liquid repellency (contact angle with a liquid of 90 to 120 °) may be applied to the upper layer of this photosensitizer. The surface of the wafer W does not necessarily have to be liquid repellent, and a resist having a contact angle with the liquid of about 60 ° to 80 ° can be used. Further, at least a part of the side surface and the back surface of the wafer W may be subjected to a liquid repellent treatment. Similarly, at least a part of the wafer holder WH and the plate holder PH may be subjected to a liquid repellent treatment.
0058The position of the wafer table WTB configured as described above is measured by the interferometer system 118 (see FIG. 6), which will be described later.
0059As shown in FIG. 2, the measurement stage MST is composed of a combination of a plurality of members such as the Y stage 81 whose longitudinal direction is the X-axis direction, and the lowermost surface thereof (the member closest to the base plate 12). It is non-contactly supported above the upper surface (guide surface) of the base plate 12 via a plurality of gaseous static pressure bearings provided on the lower surface), for example, an air bearing, with a clearance of about several μm.
0060As can be seen from the perspective view of FIG. 3, the measurement stage MST is fixed to a rectangular plate-shaped measurement stage main body 81c elongated in the X-axis direction and the upper surface of the measurement stage main body 81c on one side and the other side in the X-axis direction, respectively. A Y stage 81 having a pair of protruding portions 81a and 81b, a leveling table 52 arranged above the upper surface of the measurement stage main body 81c, and a measurement table MTB provided on the leveling table 52 are provided. ing.
0061An electric machine having a plurality of armature coils arranged at predetermined intervals along the Y-axis direction on one side and the other end face of the measurement stage main body 81c forming a part of the Y stage 81 in the X-axis direction. Movables 84 and 85, which consist of child units, are fixed, respectively. Each of these movers 84 and 85 is inserted from the inside into the stators 86 and 87 for the Y-axis described above, respectively. That is, in the present embodiment, two moving coils are formed by a mover 84,85 composed of an armature unit and a stator 86,87 for the Y axis composed of a magnetic pole unit into which each of the mover 84,85 is inserted. A type Y-axis linear motor is configured. In the following, each of the above two Y-axis linear motors will be referred to as a Y-axis linear motor 84 and a Y-axis linear motor 85 as appropriate, using the same reference numerals as the movers 84 and 85, respectively. In the present embodiment, these Y-axis linear motors 84 and 85 drive the entire measurement stage MST in the Y-axis direction. The Y-axis linear motors 84 and 85 may be used as a moving magnet type linear motor.
0062The plurality of gas static pressure bearings described above are provided on the bottom surface of the measurement stage main body 81c. The pair of protrusions 81a and 81b described above are fixed facing each other on one side of the upper surface of the measurement stage main body 81c in the X-axis direction and near the + Y side end on the other side. Between these protrusions 81a and 81b, a stator 61 and a stator 63 extending in the X-axis direction in the XY plane are erected at predetermined intervals in the Z-axis direction (upper and lower).
0063A mover of the X voice coil motor 54a is provided on the + X side end surface of the leveling table 52, and the stator of the X voice coil motor 54a is fixed to the upper surface of the measurement stage main body 81c. Further, on the end face on the -Y side of the leveling table 52, movers of Y voice coil motors 54b and 54c are provided, respectively, and the stators of these Y voice coil motors 54b and 54c are placed on the upper surface of the measurement stage main body 81c. It is fixed. The X-voice coil motor 54a is composed of, for example, a mover composed of a magnetic pole unit and a stator composed of an armature unit, and generates a driving force in the X-axis direction by electromagnetic interaction between them. Further, the Y voice coil motors 54b and 54c are also configured in the same manner to generate a driving force in the Y-axis direction. That is, the leveling table 52 is driven in the X-axis direction with respect to the Y stage 81 by the X voice coil motor 54a, and is driven in the Y-axis direction with respect to the Y stage 81 by the Y voice coil motors 54b and 54c. Further, by making the driving forces generated by the voice coil motors 54b and 54c different, the leveling table 52 can be driven in the rotation direction (θz direction) around the Z axis with respect to the Y stage 81.
0064Inside the leveling table 52, three Z voice coil motors (not shown) that generate a driving force in the Z-axis direction are arranged respectively.
0065That is, the leveling table 52 has 6 degrees of freedom direction (X, Y, Z, θx) by the above-mentioned X voice coil motor 54a, Y voice coil motor 54b, 54c, and Z voice coil motor (not shown) arranged inside. , θy, θz) can be driven minutely without contact.
0066Returning to FIG. 3, the measurement table MTB is fixed vertically on the + Y side surface of the measurement table main body 59 and the measurement table main body 59, and is movable in a substantially U-shaped cross section with the X-axis direction as the longitudinal direction. It has children 62 and 64.
0067The mover 62 includes a mover yoke having a substantially U-shaped cross section in YZ, and N-pole permanent magnets and S that are alternately arranged at predetermined intervals along the X-axis direction on the inner surface (upper and lower surfaces) of the mover yoke. It is provided with a permanent magnet group composed of a plurality of sets of polar permanent magnets, and is engaged with the above-mentioned stator 61. An alternating magnetic field is formed along the X-axis direction in the internal space of the mover yoke of the mover 62. The stator 61 includes, for example, an armature unit containing a plurality of armature coils arranged at predetermined intervals along the X-axis direction. That is, the stator 61 and the mover 62 constitute a moving magnet type X-axis linear motor LX that drives the measurement table MTB in the X-axis direction.
0068The mover 64 includes a mover yoke having a substantially U-shaped cross section in YZ, and an N-pole permanent magnet and an S-pole permanent magnet provided on the inner surface (upper and lower surfaces) of the mover yoke, respectively. It is engaged with the stator 63. A magnetic field in the + Z direction or the -Z direction is formed in the internal space of the mover yoke of the mover 64. The stator 63 includes an armature coil arranged therein so that a current flows only in the X-axis direction in a magnetic field formed by an N-pole magnet and an S-pole magnet. That is, the mover 64 and the stator 63 constitute a moving magnet type Y voice coil motor VY that drives the measurement table MTB in the Y-axis direction.
0069As is clear from the above description, in the present embodiment, the Y-axis linear motors 82 to 85, the X-axis linear motor 80, the Z / tilt drive mechanism (not shown) for driving the wafer table WTB, and the above-mentioned measurement stage MST. The stage drive system 124 shown in FIG. 6 is configured by each of the motors (54a to 54c, LX, VY and Z voice coil motor (not shown)). Various drive mechanisms constituting the stage drive system 124 are controlled by the main controller 20 shown in FIG.
0070The measurement table MTB further includes measuring instruments for performing various measurements related to exposure. More specifically, as shown in FIG. 3, a plate 101 made of a glass material such as zerodur (trade name of Schott AG) or quartz glass is provided on the upper surface of the measurement table main body 59. Chromium is applied to almost the entire surface of this plate 101, and there are areas for measuring instruments, high and low reference reflecting surface areas used for measuring reticle transmittance, and Japanese Patent Application Laid-Open No. 5-21314. A reference mark area FM is provided in which a plurality of reference marks are formed, which are disclosed in the corresponding US Pat. Nos. 5,243,195, JP-A-10-050600, and the corresponding US Pat. Nos. 6,243,158. Has been done. This reference mark area constitutes a measuring member. The surface of the plate 101 is a flat surface.
0071The area for the measuring instrument is patterned to form various measurement opening patterns. As the measurement aperture pattern, for example, a spatial image measurement aperture pattern (for example, a slit-shaped aperture pattern), a pinhole aperture pattern for illumination unevenness measurement, an illuminance measurement aperture pattern, a wave surface aberration measurement aperture pattern, and the like are formed. There is.
0072Inside the measurement table main body 59 below the aperture pattern for measuring the spatial image, the exposure light (illumination light) IL irradiated to the plate 101 via the projection optical system PL and water is introduced into the aperture pattern for measuring the spatial image. A light receiving system that receives light is provided by the projection optical system PL disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-14005 and the corresponding US Patent Application Publication No. 2002/0041377. A spatial image measuring instrument that measures the light intensity of the spatial image (projected image) of the projected pattern is configured.
0073Further, a light receiving system including a light receiving element is provided inside the measurement table main body 59 below the pinhole opening pattern for measuring uneven illumination, thereby corresponding to Japanese Patent Application Laid-Open No. 57-117238 and the corresponding light receiving system. An illuminance unevenness measuring instrument having a pinhole-shaped light receiving portion that receives illumination light IL on the image plane of the projection optical system PL disclosed in US Pat. No. 4,465,368 and the like is configured.
0074Further, a light receiving system including a light receiving element is provided inside the measurement table main body 59 below the opening pattern for illuminance measurement, whereby, for example, Japanese Patent Application Laid-Open No. 11-16816 and the corresponding US patent application. An illuminance monitor having a light receiving portion having a predetermined area for receiving the illumination light IL through water on the image plane of the projection optical system PL disclosed in Japanese Patent Application Laid-Open No. 2002/0061469 is configured.
0075In addition, a light receiving system including, for example, a microlens array is provided inside the measurement table main body 59 below the aperture pattern for wave surface aberration measurement, for example, International Publication No. 99/60361 and the corresponding European publication No. 99/60361. The wave surface aberration measuring instrument disclosed in Japanese Patent No. 1,079,223 and the like is configured.
0076In FIG. 6, the above-mentioned spatial image measuring instrument, illuminance unevenness measuring instrument, illuminance monitor, and wave surface aberration measuring instrument are shown as measuring instrument group 43.
0077In this embodiment, it is used for measurement using the illumination light IL in response to the immersion exposure in which the wafer W is exposed by the exposure light (illuminance light) IL via the projection optical system PL and water. In the above-mentioned illuminance monitor, illuminance unevenness measuring instrument, spatial image measuring instrument, wave surface aberration measuring instrument, etc., the illumination light IL is received through the projection optical system PL and water. Therefore, a water-repellent coat may be applied to the surface of the plate 101. Further, in each of the above measuring instruments, for example, only a part of the optical system or the like may be mounted on the measurement stage MST, or the entire measuring instrument may be arranged on the measurement stage MST. Further, the above-mentioned spatial image measuring instrument, illuminance unevenness measuring instrument, illuminance monitor and wave surface aberration measuring instrument do not necessarily have to be all provided, and only a part thereof may be mounted if necessary.
0078The position of the measurement stage MST (measurement table MTB) configured as described above is measured by the interferometer system 118 (see FIG. 6) described later.
0079Further, in the exposure apparatus 100 of the present embodiment, the holding member holding the projection unit PU is provided with an off-axis alignment system (hereinafter, abbreviated as "alignment system") ALG shown in FIG. .. Examples of this alignment system ALG include Japanese Patent Application Laid-Open No. 2001-257157 and the corresponding US Patent Application Publication No. 2001/0023918, Japanese Patent Application Laid-Open No. 8-213306, and the corresponding US Patent No. 5,783,833. A broadband detection light beam that does not expose the resist on the wafer, which is disclosed in a document, is applied to the target mark, and an image of the target mark formed on the light receiving surface by the reflected light from the target mark and an index (not shown) (not shown). Alignment system FIA (Field Image Alignment) system, which is an image processing method that captures an image of an index pattern on an index plate provided in the ALG using an image sensor (CCD, etc.) and outputs those image pickup signals. A sensor is used. The image pickup signal from the alignment system ALG is supplied to the main control device 20 of FIG.
0080The alignment system ALG is not limited to the FIA system, but the target mark is irradiated with coherent detection light to detect scattered light or diffracted light generated from the target mark, or two diffractions generated from the target mark. Of course, it is possible to use an alignment sensor that detects by interfering with light (for example, diffracted light of the same order or diffracted light diffracted in the same direction) alone or in combination as appropriate.
0081A water-repellent cover is provided on the members that are placed near the moving surface of the wafer table WTB, such as the optical elements of the alignment ALG and the holding members that hold the optical elements, and where there is a concern that the liquid may adhere due to the scattering of the liquid. You may. Further, a seal member such as an O-ring is arranged in a gap where there is a concern that a liquid may enter the inside of the alignment system ALG, such as a gap between the optical element and a holding member that holds the optical element. Further, the surface of the optical member arranged near the moving surface of the wafer table WTB, such as the surface of the optical element at the end (lower end) of the alignment system ALG and the mirror surface for the interferometer fixed to the alignment system ALG, is liquid repellent. It is coated with a sex material to prevent water from adhering to it, and even if water adheres, it can be easily wiped off by an operator or other operator.
0082Further, in the exposure apparatus 100 of the present embodiment, although not shown in FIG. 1, the exposure system 90a and the light receiving system 90b (see FIG. 6) are included, for example, Japanese Patent Application Laid-Open No. 6-283403 and corresponding thereto. A multi-point focal position detection system of the oblique incidence method similar to that disclosed in US Pat. No. 5,448,332 is provided. In the present embodiment, as an example, the irradiation system 90a is suspended and supported by a holding member that holds the projection unit PU on the -X side of the projection unit PU, and the light receiving system 90b is held on the + X side of the projection unit PU. It is suspended and supported below. That is, the irradiation system 90a, the light receiving system 90b, and the projection optical system PL are attached to the same member, and the positional relationship between the two is maintained constant.
0083Next, the configuration and operation of the interferometer system 118 will be described.
0084The end face on the -X side and the end face on the -Y side of the wafer table WTB are mirror-finished, and as shown in FIG. 2, reflective surfaces 17X and 17Y are formed, respectively. In addition, the end face on the -X side, the end face on the + Y side, and the end face on the -Y side of the measurement table MTB are mirror-finished, and the reflective surfaces 117X and 117Y, respectively.<sub>1</sub>, 117Y<sub>2</sub>Is formed.
0085The interferometer system 118 includes Y-axis interferometers 16, 18, 78 and X-axis interferometers 46, 66, 76, as shown in FIG.
0086Both the Y-axis interferometers 16 and 18 have a length-measuring axis parallel to the Y-axis connecting the projection center (optical axis AX) of the projection optical system PL and the detection center of the alignment system ALG. Both of these Y-axis interferometers 16 and 18 are multi-axis interferometers having at least three optical axes, and the output value of each optical axis can be measured independently. Further, the X-axis interferometer 46 has a length-measuring axis that vertically intersects the length-measuring axes of the Y-axis interferometers 16 and 18 at the projection center of the projection optical system PL. Further, the X-axis interferometer 66 has a length-measuring axis that vertically intersects the length-measuring axes of the Y-axis interferometers 16 and 18 at the detection center of the alignment system ALG. Both of these X-axis interferometers 46 and 66 are multi-axis interferometers having at least two optical axes, and the output value of each optical axis can be measured independently. The output values (measured values) of the above four interferometers 16, 18, 46, and 66 are supplied to the main controller 20 shown in FIG. For example, in the state of FIG. 5, the interferometer beam (length measuring beam) from the Y-axis interferometer 16 is the reflection surface 117Y of the measurement table MTB.<sub>1</sub>The interferometer beam (length measuring beam) from the Y-axis interferometer 18 is projected onto the reflecting surface 17Y of the wafer table WTB, and the interferometer beam (length measuring beam) from the X-axis interferometer 46 is projected onto the measuring table MTB. The interferometer beam (length measuring beam) from the X-axis interferometer 66 is projected onto the reflecting surface 17X of the wafer table WTB. The interferometers 16, 18, 46, and 66 receive the reflected light from each of the reflecting surfaces of the length measuring beam of each optical axis, so that the reference position of each reflecting surface (generally, the projection unit PU) is received for each optical axis. A fixed mirror is placed on the side surface or the side surface of the off-axis alignment system ALG (see Fig. 6, Fig. 5, etc.), and the displacement in the measurement direction from that is used as the reference surface).
0087In the case of FIG. 5, in the main controller 20, based on the output value from the Y-axis interferometer 18, not only the position of the wafer table WTB in the Y-axis direction (Y position) but also the amount of rotation around the X-axis (pitching amount). And the amount of rotation (yawing amount) around the Z axis is also measured. Further, in the main controller 20, based on the output value from the Y-axis interferometer 16, not only the position (Y position) of the measurement table MTB in the Y-axis direction, but also the rotation amount (pitching amount) around the X-axis and Z. The amount of rotation around the axis (yawing amount) is also measured. Further, in the main controller 20, based on the output value (measured value) of the X-axis interferometer 66, not only the position of the wafer table WTB in the X-axis direction (X position) but also the amount of rotation around the Y-axis (rolling amount). ) Is also measured. Further, the main controller 20 measures the X position and the rolling amount of the measurement table MTB based on the output value from the X-axis interferometer 46.
0088As can be seen from FIG. 5, in the present embodiment, the interferometer beam from the Y-axis interferometer 18 is always projected onto the reflecting surface 17Y over the entire moving range during alignment and exposure of the wafer stage WST, resulting in Y-axis interferometry. The interferometer beam from a total of 16 is always on the reflective surface 117Y over the entire range of movement of the measurement stage MST.<sub>1</sub>It is designed to be projected on. Therefore, in the Y-axis direction, the Y positions of the stages WST and MST interfere with each other by the main controller 20 except when the wafer stage WST moves to the wafer exchange position indicated by the alternate long and short dash line in FIG. It is managed based on a total of 18 and 16 measured values.
0089On the other hand, as can be seen from FIGS. 2 and 5, the main controller 20 is based on the output value of the X-axis interferometer 46 in the range where only the interferometer beam from the X-axis interferometer 46 hits the reflecting surface 17X. The X position of the wafer table WTB (wafer stage WST) is managed, and the measurement table is based on the output value of the X-axis interferometer 46 within the range where only the interferometer beam from the X-axis interferometer 46 hits the reflection surface 117X. Manage the X position of MTB (Measurement Stage MST). Further, in the main controller 20, the X position of the wafer table WTB (wafer stage WST) is based on the output value of the X-axis interferometer 66 in the range where only the interferometer beam from the X-axis interferometer 66 hits the reflecting surface 17X. And manage the X position of the measurement table MTB (measurement stage MST) based on the output value of the X-axis interferometer 66 within the range where only the interferometer beam from the X-axis interferometer 66 hits the reflecting surface 117X. ..
0090Further, the main controller 20 includes the range in which the interferometer beams from the X-axis interferometer 46 and the X-axis interferometer 66 simultaneously hit the reflecting surface 17X, and the wafer table WTB (wafer stage WST) is used for wafer alignment. The X position is managed by using the X-axis interferometer 66, and the X position of the wafer table WTB (wafer stage WST) at the time of exposure is managed by using the X-axis interferometer 46. As a result, the X position of the wafer table WTB (wafer stage WST) can be managed without any error during both wafer alignment and exposure.
0091The remaining X-axis interferometer 76 and Y-axis interferometer 78 are interferometers for controlling the position of the wafer stage WST when it is in the vicinity of the wafer exchange position that cannot be controlled by the interferometers 46, 66, and 18. Based on the measurements of these interferometers 76,78, the main controller 20 cannot manage the X position based on the output values of the interferometers 46,66,18, while the wafer table WTB (wafer stage WST position). To manage.
0092Further, when the measurement stage MST is in the standby position on the + Y side according to the state shown in FIG. 5, not only the X-axis interferometer 66 but also the interferometer beam from the X-axis interferometer 46 does not hit the reflecting surface 117X. When moving the measurement stage MST from this state in the -Y direction, the main controller 20 immediately after the interferometer beam from the X-axis interferometer 46 starts hitting the reflecting surface 117X from the state where it does not hit the reflecting surface 117X. Then, the X-axis interferometer 46, which was not used for control until then, is reset, and after that, the X-axis interferometer 46 is used to manage the X position of the measurement table MTB (measurement stage MST). Other interferometers can perform a reset (joint reset) operation using the output (measured value) of an adjacent interferometer. That is, at the time immediately before the reset of each interferometer, when the length measuring beams from the two adjacent interferometers are simultaneously irradiated on the reflecting surface, the position of the wafer stage WST or the measurement stage MST until immediately before that. By taking over the measured values of the X-axis interferometer or Y-axis interferometer used for control and resetting (presetting) the interferometer to be reset, the interferometer after the reset can be used without any trouble on the wafer stage. The position of WST or measurement stage MST can be managed. Of course, an interferometer that measures the position of the measurement table MTB in the X-axis direction when the measurement table MTB is in the standby position may be added.
0093Further, in the exposure apparatus 100 of the present embodiment, the wafer replacement position (loading position) is set at a position near the + X side end and the -Y side end of the movable range of the wafer stage WST. When the wafer stage WST is located at the wafer replacement position, reticle alignment and baseline measurement of the alignment system ALG are performed. When the wafer stage WST is at the wafer replacement position, the interferometer beam (length measurement beam) from the Y-axis interferometer 18 is the reflection surface 117Y of the measurement table MTB.<sub>2</sub>Prior to this, the main controller 20 resets the measured value of the Y-axis interferometer 18. Then, the main controller 20 manages the position of the measurement table MTB using the Y-axis interferometer 18 and the X-axis interferometer 46 after the reset, and performs a series of reticle alignment and baseline measurement of the alignment system ALG. Start operation. This is the above-mentioned reference mark on the measurement table MTB while managing the position of the measurement table MTB using the Y-axis interferometer 18 used for position measurement of the wafer table WTB (wafer stage WST) during wafer alignment and exposure. By measuring the baseline using the region FM and controlling the position of the wafer table WTB during exposure using the measured baseline, there is no position error due to the difference in the interferometer used for control. To do so.
0094In the present embodiment, at the time of reticle alignment, the main control device 20 controls the opening and closing of each valve of the liquid supply device 88 and the liquid recovery device 92 of the immersion mechanism 132 as described above, and the projection optical system. Water Lq is always filled between the tip lens 91 of the PL and the reference mark area FM of the measurement table MTB. Then, the relative position (first relative position) of at least a pair of reticle alignment marks on the reticle R and at least a pair of first reference marks on the corresponding reference mark area FM is set by the main controller 20 in the reticle alignment detection system. Detected using RAa and RAb, then the measurement table MTB is moved to the position where the reference mark area FM is located directly under the alignment system ALG based on the design value of the baseline, and water Lq exists on the reference mark area FM. In this state, the second reference mark on the reference mark area FM is detected using the alignment system ALG, and the relative position (second relative position) between the detection center of the alignment system ALG and the second reference mark is detected. Will be done. Then, in the main controller 20, the alignment system ALG is based on the first relative position, the second relative position, the design value of the baseline, and the positional relationship between the pair of first reference marks and the second reference mark. Calculate the baseline of.
0095In this embodiment, the three Y-axis interferometers 16,18,78 and the three X-axis interferometers 46,66,76 constitute the interferometer system 118 of FIG. The configuration of the metering system is only an example, and it goes without saying that the present invention is not limited thereto.
0096Returning to FIG. 1, the exposure apparatus 100 is provided with a transfer arm 70 for transporting the wafer to the wafer stage WST. The transfer arm 70 may be a slide type arm as long as it transfers the wafer between a prealigning device (not shown) that detects the center position and the rotation angle of the wafer and the wafer stage WST at the wafer exchange position. Or a horizontal articulated robot arm or the like may be used. In the present embodiment, the transfer arm 70, a pre-alignment device (not shown), a transfer unit that transfers the wafer from the outside to the pre-alignment device, and the like are included, and a transfer system 72 that transfers the wafer to the wafer stage WST (FIG. 6) is configured.
0097FIG. 6 shows the main configuration of the control system of the exposure apparatus 100. This control system is mainly composed of a main control device 20 composed of a microprocessor (or workstation) that controls the entire device in an integrated manner.
0098By the way, as described above, the positions of the wafer table WTB and the measurement table MTB in the XY plane can be measured by each interferometer of the interferometer system 118 with a resolution of about 0.5 to 1 nm. Since there is no mark or the like that serves as a reference for position measurement in 50, for example, after the interferometer beams from all Y-axis interferometers or all X-axis interferometers do not hit the reflective surface of the wafer table WTB, at least It is difficult to return the wafer table WTB to the reference state (or the state before the last interferometer beam was cut) after resetting one interferometer. Further, in the present embodiment, since the periphery of the liquid repellent plate 50 projects outward from the wafer table WTB (reflection surface), the wafer table WTB so that the outer peripheral edge of the liquid repellent plate 50 does not collide with other members. It is difficult to control the position. In particular, it becomes difficult to control the position of the wafer table WTB immediately after the liquid repellent plate 50 is replaced. In view of this point, in the exposure apparatus 100 of the present embodiment, the position of the liquid repellent plate 50 is measured by the main control device 20 as follows, and the position management of the wafer table WTB is performed based on the measurement result. Will be done.
0099As an example, FIG. 7 shows a flowchart showing the processing algorithm of the main controller 20 (internal CPU) during the return operation of the wafer table WTB to the reference state, which is executed after the replacement of the liquid repellent plate 50. ing. It is assumed that this processing algorithm is started when the wafer stage WST moves to the position shown in FIG. 8 immediately after the measured value of the interferometer 18 is reset. At this time, the position of the wafer table WTB is controlled by the main controller 20 based on the measured values of the interferometers 18 and 76. The rotation error of the wafer table WTB itself in the θz direction shall be small enough to be ignored. Further, as described above, when the wafer table WTB (wafer stage WST) or the like moves, the above-mentioned interferometer measurement value connection preset is executed. However, in the following description of the processing algorithm, the description is simplified. Therefore, the explanation about the connection preset of the measured values of the interferometer is omitted, and the wafer stage WST (wafer table WTB) on the stage coordinate system (X, Y) defined by the length measurement axis of the interferometer system 118. The position of is managed. Since the measured values of the adjacent X-axis interferometers and the measured values of the Y-axis interferometers are inherited in sequence in the connection preset, it is considered that there is no particular problem even if this assumption is made.
0100First, in step 202 of FIG. 7, the count value n of the first counter indicating the number of the measurement point of the outer peripheral edge of the liquid repellent plate 50 is initialized to 1 (n 1). Here, it is assumed that N regions, here four regions, that is, the central points of the upper, lower, left, and right edges of the liquid repellent plate 50 are defined as the measurement target regions.
0101In the next step 204, the position of the wafer table WTB is measured using the interferometer system 118, and the nth (here, the first) measurement point on the outer peripheral edge of the liquid repellent plate 50 is set to the alignment system ALG. Move the wafer stage WST to position it directly below.
0102FIG. 9A shows the state when the first measurement point on the outer peripheral edge of the liquid repellent plate 50 on the wafer table WTB (wafer stage WST) is positioned in the imaging field of view of the alignment system ALG. ing. In FIGS. 9 (A) to 9 (D), the reference numeral ALG'indicates the imaging field of view of the alignment system ALG.
0103Returning to FIG. 7, in step 206, the nth (here, the first) measurement point on the outer peripheral edge is imaged using the alignment system ALG, and the imaged data (imaging signal) is captured and the image is taken. The measured value of the interferometer system 118 at that time is taken in, and both are stored in association with each other in a memory (not shown).
0104In the next step 208, it is determined whether or not the count value n of the first counter has reached N (here, N = 4). At this time, since n = 1, the judgment here is denied, the process proceeds to step 210, the count value n of the first counter is incremented by 1, and then the process returns to step 204.
0105After that, the loop processing of steps 204 206 208 210 is repeated until the determination in step 208 is affirmed. As a result, the wafer table WTB is sequentially positioned from the position shown in FIG. 9 (A) to the positions shown in FIGS. 9 (B), 9 (C), and 9 (D), and the liquid repellent plate is positioned at each positioning position. The outer peripheral edges of 50 are imaged using the alignment system ALG, and the position information (measured value of the interferometer system 118) of the wafer table WTB corresponding to the imaged data is stored in the memory.
0106Then, when the acquisition of the imaging data and the like of the edge on the -X side of the liquid repellent plate 50 shown in FIG. 9D is completed, the judgment in step 208 is affirmed, and the process proceeds to step 212.
0107In step 212, based on the imaging data (imaging result) of each edge and the measurement result of the corresponding interferometer system 118 stored in the memory, the first to the first of the liquid repellent plate 50 by the image processing method. Acquires the position information of the measurement point of the Nth (4th in this case) outer peripheral edge.
0108In the next step 214, the position information of the liquid repellent plate 50, for example, a predetermined reference point (for example, the center point) of the liquid repellent plate 50 is based on the position information of the outer peripheral edges of the obtained N points (here, 4 points). After calculating the position information and the like on the stage coordinate system (X, Y) of, the process of step 216 is performed as necessary, and then the process shown in the flowchart of FIG. 7 is completed.
0109Based on the position information of the outer peripheral edge of the liquid repellent plate 50 or the position information of the liquid repellent plate 50 measured in this way, the subsequent position management of the wafer table WTB is performed by the main control device 20. For example, in the main controller 20, the position information of the outer edge of the liquid repellent plate 50 or the position information of the liquid repellent plate 50 so that the outer peripheral edge of the liquid repellent plate 50 mounted on the wafer table WTB does not collide with the measurement stage MST. At least one of the position of the wafer table WTB (wafer stage WST) and the position of the measurement stage MST is controlled based on the above.
0110Here, for example, when the process of step 216 is performed, the position information of a part of the wafer holder is acquired in the same manner as the position information of the liquid repellent plate 50 described above, and the position information and the position information and step 212 or 214 are described. Based on the acquired position information of the liquid repellent plate 50, the positional relationship between the wafer holder WH (wafer table WTB) and the liquid repellent plate is calculated.
0111Here, for example, when measuring the θz rotation of the liquid repellent plate 50, the measurement points of the outer peripheral edge of the liquid repellent plate 50 are set in advance at a plurality of points (that is, five or more points in total) on at least one edge. It may be set and the process may be performed according to the same flowchart as in FIG. 7 described above. FIG. 10A shows how the wafer table WTB moves when the position information of a plurality of measurement points on the edge of the + Y side end of the liquid repellent plate 50 is sequentially measured. Then, in this case, in step 214 described above, as the position information of the liquid repellent plate 50, in addition to the position information of the reference point, at least two points on the edge in which the regions to be measured at the plurality of points are set. The θz rotation of the edge (that is, the angle of rotation of the liquid repellent plate 50 with respect to the stage coordinate system) may also be calculated based on the position information of.
0112In this case, a plurality of measurement points may be set on each of the four edges of the liquid repellent plate 50, and the θz rotation of each edge may be obtained. For example, as schematically shown in FIG. 10B, for example, three measurement points may be set for each of the four edges, and the average value of the θz rotation of each obtained edge may be calculated. .. Actually, the imaging field of view ALG'of the alignment system ALG is fixed and the wafer table WTB moves, but in FIG. 10B, for convenience, whether the imaging field of view ALG' moves with respect to the fixed wafer table WTB. Is illustrated as.
0113In the present embodiment, the outer peripheral edge of the liquid repellent plate 50 is imaged at a plurality of locations including two locations symmetrical with respect to the substantially center of the liquid repellent plate 50, but the imaging locations are limited to these. However, it does not have to be two places symmetrical with respect to the center of the liquid repellent plate 50. For example, the outer peripheral edge may be imaged at a plurality of places including one place of the outer peripheral edge of one side of the liquid repellent plate 50 and one place of the outer peripheral edge of the other side facing the one side. In this case, since it is possible to acquire a substantially symmetrical image of the outer peripheral edges of at least two opposite sides, the position information (for example, the center position) of the liquid repellent plate 50 can be calculated.
0114Next, regarding a series of processes from the replacement of the liquid-repellent plate on the wafer table WTB to the next replacement of the liquid-repellent plate performed by the exposure apparatus 100 of the present embodiment, the main control device 20 (internal). The processing algorithm of the CPU) will be described based on the flowcharts of FIGS. 11 and 12, and with reference to other drawings as appropriate. In the following description of the processing algorithm, the description of the above-mentioned connection preset of the measured values of the interferometer is omitted, and the wafer stage is set on the stage coordinate system (X, Y) defined by the length measurement axis of the interferometer system 118. The position of the WST (wafer table WTB) shall be controlled.
0115First, in step 222 of FIG. 11, a subroutine process for measuring the position information of the inner peripheral edge of the opening of the liquid repellent plate is executed.
0116In the subroutine of this step 222, first, in step 302 of FIG. 13, the count value m of the second counter indicating the order of the measurement points of the inner peripheral edge of the opening 50a of the liquid repellent plate 50 is initialized to 1 (m ). 1). Here, the measurement points are M, here eight, that is, each of the eight lines extending radially from the center of the opening 50a of the liquid repellent plate 50 in eight directions with a central angle of 45 ° including the vertical and horizontal directions. It is assumed that eight points, which are the intersections of and the inner peripheral edge, are defined.
0117In the next step 304, the position of the wafer table WTB is measured using the interferometer system 118, and the mth (here, the first) measurement point on the inner peripheral edge of the opening 50a of the liquid repellent plate 50 is determined. The wafer table WTB (wafer stage WST) is moved to position it directly below the imaging field of view of the alignment system ALG.
0118FIG. 15A shows the state when the first measurement point is positioned in the imaging field of view of the alignment system ALG. In FIGS. 15 (A) to 15 (D) and 16 (A) to 16 (D), the reference numeral ALG'indicates the imaging field of view of the alignment system ALG.
0119In the next step 306, the mth (here, the first) measurement point on the inner peripheral edge of the opening 50a is imaged using the alignment system ALG, and the imaged data (imaging signal) is captured and the image is taken. The measured value of the interferometer system 118 at that time is taken in, and both are stored in association with each other in a memory (not shown).
0120In the next step 308, it is determined whether or not the count value m of the second counter has reached M (here, M = 8). At this time, since m = 1, the judgment here is denied, the process proceeds to step 310, the count value m of the second counter is incremented by 1, and then the process returns to step 304.
0121After that, the loop processing of steps 304 306 308 310 is repeated until the determination in step 308 is affirmed. As a result, from the position of FIG. 15 (A), FIG. 15 (B), FIG. 15 (C), FIG. 15 (D), FIG. 16 (A), FIG. 16 (B), FIG. 16 (C), FIG. The wafer table WTB is sequentially positioned at the positions shown in (D), and at each positioning position, the inner peripheral edge of the opening 50a of the liquid repellent plate 50 is imaged using the alignment system ALG, and the wafer table corresponding to the imaged data is imaged. The WTB position information (measured value of the interferometer system 118) is stored in the memory .
0122Then, when the acquisition of the imaging data of the eighth measurement point on the inner peripheral edge of the opening 50a shown in FIG. 16 (D) is completed, the determination in step 308 is affirmed, and the process proceeds to step 314. At this point, as schematically shown in FIG. 17 (A), the image data of eight locations on the inner peripheral edge of the opening 50a and the position information data of the corresponding wafer table WTB are stored in the memory. .. Actually, the image pickup field of view ALG'of the alignment system ALG is fixed and the wafer table WTB moves, but in FIG. 17 (A), for convenience, whether the image pickup field of view ALG'moves with respect to the fixed wafer table WTB. Is illustrated as.
0123In step 314, based on the imaging data (imaging results) of M points (here, 8 points) on the inner peripheral edge of the opening 50a and the measurement results of the corresponding interferometer system 118 stored in the memory. After acquiring the position information of the 1st to Mth (8th in this case) measurement points on the inner peripheral edge of the opening 50a of the liquid repellent plate 50 by the image processing method, the processing of this subroutine is terminated. Then, return to step 224 (see FIG. 11) of the main routine.
0124In step 224, based on the position information of the inner peripheral edge of the opening 50a at the M points (8 places in this case) obtained, the position information of the opening 50a of the liquid repellent plate 50, for example, by the minimum square method or the like. Calculate the position information of a predetermined reference point (for example, the center point) of 50a on the stage coordinate system (X, Y) (that is, based on the position information of the inner peripheral edge, and the stage coordinate system set by the interferometer system 118. After determining the positional relationship with the opening 50a), the process proceeds to step 226.
0125In step 226, based on the position information of the inner peripheral edge of the opening 50a at the above M points (8 places in this case), the shape information of the opening 50a of the liquid repellent plate 50 (this shape information includes at least a perfect circle of the opening 50a). (Including degree) is calculated by a predetermined operation. Here, the roundness is an evaluation quantity indicating the deviation of the opening 50a from the ideal perfect circle, and can be defined as the difference between the maximum radius and the minimum radius of the contour of the opening 50a with respect to the center of the opening 50a. Here, the center of the circle, which is the reference of the roundness, may be the center calculated by any of the following methods a. To d. Minimum region center method (MZC): The center where the difference in radius of the concentric circles is minimized when the contour of the opening is sandwiched between two concentric circles, b. Minimum squared center method (LSC): Minimum squared mean circle (from the reference circle) The center of the circle that minimizes the sum of squares of the deviations), c. The minimum circumscribing circle center method (MCC): the center of the circle that is the smallest circumscribing to the contour of the opening, d. The center of the circle that is at most inscribed in the contour.
0126In the next step 228, it is determined whether or not the roundness calculated in the above step 226 is less than the first threshold value. Here, the first threshold value is set to the limit value at which the liquid repellent plate can be used. Therefore, if the judgment in step 228 is denied, the liquid-repellent plate 50 is a plate having an opening with insufficient roundness to the extent that it cannot be used by this exposure apparatus. After moving to step 264 and notifying the operator of the defect of the liquid repellent plate by displaying "defective liquid repellent plate (replacement required)" on a display (not shown), the process of this routine is terminated. After that, by confirming this notification (display), the operator stops the operation of the exposure apparatus 100 and manually replaces the liquid repellent plate 50. If a robot or the like used for replacing the liquid repellent plate 50 is provided, the main control device 20 displays the replacement time on the display, stops the operation of the device, and uses the robot or the like. , It is also possible to replace the liquid repellent plate.
0127On the other hand, if the determination in step 228 is affirmed, the process proceeds to the next step 230 to determine whether or not the roundness calculated in step 226 is less than the second threshold value. If this judgment is denied, the process proceeds to step 234, and the transfer arm 70 of the transfer system 72 and the above-mentioned center-ups 34a to 34c are used on the wafer holder WH inside the opening 50a of the liquid repellent plate 50. After loading the tool wafer W1 (see FIG. 17 (B)) into the subroutine, the process proceeds to a subroutine that measures the position information of the outer peripheral edge of the object in the opening in step 236. Here, the tool wafer W1 is a tool wafer having a diameter (outer diameter) slightly smaller than that of the wafer W, which is an object to be processed used for device manufacturing. Contrary to the above, if the judgment in step 230 is affirmed, the process proceeds to step 232 and the inside of the opening 50a of the liquid repellent plate 50 is used by using the transfer arm 70 of the transfer system 72 and the center-ups 34a to 34c described above. After loading the wafer W on the wafer holder WH of the above, the process proceeds to the subroutine of step 236 above. Here, at the time of this loading, at least of the wafer table WTB and the transport arm 70 based on the position information of the inner peripheral edge of the opening 50a acquired in step 222 or the position information of the opening 50a acquired in step 224. Control one position.
0128As described above, the second threshold value is set for distinguishing whether to select the tool wafer W1 or the wafer W. When the roundness of the opening 50a is high, the wafer W for device manufacturing, which has a diameter slightly different from that of the opening 50a, can be loaded on the wafer holder WH inside the opening 50a without any trouble, but the roundness of the opening 50a. If the degree is low, when the wafer W is loaded on the wafer holder WH inside the opening 50a, there is a high possibility that the wafer W and the inner peripheral edge of the opening 50a come into contact with each other, which may make loading difficult. .. Therefore, in the latter case, the tool wafer W1 having a diameter smaller than that of the wafer W is loaded on the wafer holder WH.
0129In the subroutine of step 236, first, in step 322 of FIG. 14, the measurement point of the outer peripheral edge of the object (tool wafer W1 or wafer W, hereinafter appropriately referred to as tool wafer W1) in the opening 50a. Initialize the count value k of the third counter indicating the number of to 1 (k 1). Here, the measurement points are K, here eight, that is, each of the eight lines extending radially from the center of the tool wafer W1 in eight directions with a central angle of 45 ° including the vertical and horizontal directions, and the tool wafer W1. It is assumed that eight points, which are the intersections with the outer peripheral edge of, are defined.
0130In the next step 324, the position of the wafer table WTB is measured using the interferometer system 118, and the kth (here, the first) on the outer peripheral edge of the tool wafer W1 in the opening 50a of the liquid repellent plate 50. The wafer table WTB (wafer stage WST) is moved so that the measurement point of is positioned directly below the imaging field of view of the alignment system ALG.
0131In the next step 326, the kth (here, the first) measurement point on the outer peripheral edge of the tool wafer W1 is imaged using the alignment system ALG, and the imaged data (imaging signal) is captured and the image is taken. The measured value of the interferometer system 118 at that time is taken in, and both are stored in association with each other in a memory (not shown).
0132In the next step 328, it is determined whether or not the count value k of the third counter has reached K (here, K = 8). At this time, since k = 1, the judgment here is denied, the process proceeds to step 330, the count value k of the third counter is incremented by 1, and then the process returns to step 324.
0133After that, the loop processing of steps 324 326 328 330 is repeated until the judgment in step 328 is affirmed. As a result, as shown in FIG. 17 (B), the wafer table WTB is sequentially positioned at the position where each of the eight measurement points is located within the imaging field of view ALG'of the alignment system ALG, and the tool is positioned at each positioning position. The outer peripheral edge of the wafer W1 is imaged using the alignment system ALG, and the position information (measured value of the interferometer system 118) of the wafer table WTB corresponding to the imaged data is stored in the memory.
0134Then, when the acquisition of the imaging data of the eighth measurement point on the outer peripheral edge is completed, the determination in step 328 is affirmed, and the process proceeds to step 332.
0135In step 332, it corresponds to the imaging data (imaging result) of K points (here, 8 points) on the outer peripheral edge of the object (tool wafer W1 (or wafer W)) in the opening 50a stored in the memory. Based on the measurement results of the interferometer system 118, the position information of the 1st to Kth (here, the 8th) measurement points on the outer peripheral edge of the object in the opening 50a was acquired by the image processing method. After that, the processing of this subroutine is finished, and the process returns to step 240 (see FIG. 12) of the main routine.
0136In step 240, the positional relationship between the inner peripheral edge of the opening 50a and the object in the opening 50a is acquired. Specifically, based on the position information of the above K points (8 points in this case) on the outer peripheral edge of the object in the opening 50a, the position information of the object calculated by, for example, the minimum square method (for example, the center of the object). Position information on the stage coordinate system (X, Y)) and position information of the opening 50a of the liquid repellent plate 50 obtained in step 224 above (for example, on the stage coordinate system (X, Y) of the center point of the opening 50a). Based on the position information in), the positional relationship between the inner peripheral edge of the opening 50a and the object in the opening 50a, for example, the information on the deviation between the center of the opening 50a and the center of the object (tool wafer W1 or wafer W) is calculated. To get by.
0137In the next step 242, the wafer stage WST is moved to the wafer exchange position, and the object (tool wafer W1 or wafer W) is unloaded from the wafer holder WH using the transfer arm 70 of the transfer system 72 and the center-ups 34a to 34c. To do.
0138Exposure of one lot (predetermined number of wafers) is started from the next step 244.
0139In step 244, the wafer W as the first wafer to be exposed to which prealignment (centering and rotation adjustment) has been performed by a prealigning device (not shown) that constitutes a part of the transport system 72 is transferred to the transfer arm 70. Using this, the wafer is transported to the upper part of the wafer stage WST at the wafer exchange position, and the information on the positional relationship between the inner peripheral edge of the opening 50a and the object in the opening 50a acquired in step 240, for example, the above-mentioned deviation information is taken into consideration. Then, the positional relationship between the transfer arm 70 and the wafer stage WST is adjusted, and the wafer W is loaded from the transfer arm 70 onto the wafer holder WH provided on the wafer table WTB. Here, the adjustment of the positional relationship between the transfer arm 70 and the wafer stage WST is realized by adjusting the positions of both or one of the transfer arm 70 and the wafer stage WST. In this way, after adjusting the positional relationship between the transfer arm 70 and the wafer stage WST when loading the wafer W, by loading the wafer W, normally, the outer peripheral edge of the wafer W and the opening of the liquid repellent plate 50 are opened. The distance between the outer peripheral edge of the wafer W and the inner peripheral edge of the opening 50a is a predetermined value, for example, about 0.3 mm so that the inner peripheral edge of 50a (the inner peripheral edge of the recess 140 on the upper surface of the wafer table WTB) does not come into contact. The wafer W can be loaded onto the wafer holder WH inside the inner peripheral edge of the opening 50a of the liquid repellent plate 50 above the wafer table WTB (inside the recess on the upper surface of the wafer table WTB) so as to be smaller.
0140In the next step 246, the wafer stage WST is moved below the alignment system ALG.
0141In the next step 248, the distance between the inner peripheral edge of the opening 50a of the liquid repellent plate 50 and the wafer W (outer peripheral edge) is set over the entire circumference of the wafer W by using the alignment system ALG. The procedure is the same as the measurement of the position information of the outer peripheral edge such as. At this time, in particular, it is important to set at least a plurality of sets of measurement points in directions different from the eight directions from the center of the wafer when measuring the outer peripheral edge of the wafer and the inner peripheral edge of the opening.
0142Then, in the next step 250, it is determined whether or not the interval is within the permissible range over the entire circumference of the wafer based on the measurement result of the step 248. Normally, as described above, the outer peripheral edge of the wafer W and the inner peripheral edge of the liquid repellent plate 50a (the inner peripheral edge of the concave portion on the upper surface of the wafer table WTB) do not come into contact with each other, and the outer peripheral edge of the wafer W Since the wafer W is loaded onto the wafer holder WH so that the distance between the opening 50a and the inner peripheral edge is smaller than, for example, 0.3 mm, the judgment of this step 250 is affirmed, and the process proceeds to the next step 252.
0143On the other hand, as a result of making a judgment in step 250 based on the measurement result in step 248 due to an outer diameter error of the wafer W or the like, this judgment result may be negative. Therefore, if the determination in step 250 is denied, the process proceeds to step 242 described above, and the first wafer W is unloaded from the wafer holder. Then, the operations of step 244, step 246, step 248, and step 250 are executed for the second wafer W in the same manner as described above. In this case, in step 244, when the second wafer W is loaded onto the wafer stage (wafer holder), the positions of the transfer arm and the wafer stage are taken into consideration in consideration of the measurement result of step 248 regarding the first wafer W. The relationship is adjusted. If the judgment of step 250 regarding the second wafer W is affirmed, the process proceeds to the next step 252.
0144In step 252, the alignment mark on the wafer W is detected by using the alignment system ALG, and the position information of the alignment mark is detected based on the detection result and the measured value of the interferometer system 118 at the time of the detection. Perform wafer alignment, such as enhanced global alignment (EGA).
0145In the next step 254, each on the wafer W is based on the position information of a plurality of shot regions on the wafer W obtained as a result of the above wafer alignment and the measurement result of the baseline of the latest alignment system ALG. Inter-shot movement in which the wafer stage WST is moved to the scanning start position (acceleration start position) for exposure of the shot area, and scanning exposure operation in which the pattern formed on the reticle R for each shot area is transferred by the scanning exposure method. By repeating the above steps, a plurality of shot areas on the wafer W are exposed by a step-and-scan method. At the time of this exposure, water is always filled directly under the tip lens 91 of the projection optical system PL.
0146In the next step 256, it is determined whether or not the exposure of all the wafers in one lot has been completed. If this judgment is denied, the process proceeds to step 262 to replace the exposed wafer W held in the wafer holder WH on the wafer table WTB with a new wafer, and then step 252. The process of the loop of steps 252 254 256 262 is repeated until the judgment of step 256 is affirmed.
0147On the other hand, if the determination in step 256 is affirmed, the process proceeds to step 258.
0148In the next step 258, it is determined whether or not it is time to replace the liquid repellent plate by referring to, for example, the irradiation history of the illumination light IL. Here, in the present embodiment, the relationship between the deterioration of the water-repellent coat on the surface of the liquid-repellent plate 50 and the integrated energy amount irradiated on the surface of the liquid-repellent plate 50 is obtained by an experiment in advance, and the relationship and the illumination light are obtained. Based on the IL irradiation history, it is determined that the time for replacing the liquid repellent plate 50 has arrived just before the water repellent coat deteriorates.
0149Then, when it is determined that the exchange time has arrived, the process proceeds to step 264 described above, and when it is determined that the exchange time has not arrived, the process proceeds to the processing of the next lot.
0150In this way, a series of processes from the replacement of the liquid repellent plate to the next replacement is performed.
0151As is clear from the description so far, in the present embodiment, the outer peripheral edge position acquisition device is operated by the main control unit 20, more accurately, the CPU inside the main control unit 20, and the software executed by the CPU. At least a part of each of an inner peripheral edge position acquisition device, a determination device, a shape calculation device, an object outer peripheral edge position acquisition device, an interval measuring device, a stage control device, a control device, and the like is realized. However, it goes without saying that at least a part of the components realized by these software may be configured by hardware.
0152As described above, according to the exposure apparatus 100 of the present embodiment, the interferometer system 118 is used to position the wafer table WTB (wafer stage WST) on which the liquid repellent plate 50 is detachably mounted by the main control device 20. While measuring, a part of the liquid repellent plate 50 is detected using the alignment system ALG, and the position of the outer peripheral edge of the liquid repellent plate 50 is based on the detection result and the measurement result of the corresponding interferometer system 118. Information is acquired (steps 204-210). Therefore, as in the present embodiment, even if there is no mark for position measurement on the wafer table WTB (wafer stage WST), the liquid repellent plate is based on the position information of the outer peripheral edge of the liquid repellent plate 50. The position of 50, that is, the position of the wafer table WTB (wafer stage WST) can be managed on the moving coordinate system (stage coordinate system) set by the interferometer system.
0153Further, even when the outer circumference of the liquid repellent plate 50 projects outward from the wafer table WTB as in the present embodiment, the outer peripheral edge of the liquid repellent plate 50 does not collide with other members (for example, measurement stage MST). As described above, the position of the wafer table WTB (wafer stage WST) can be controlled.
0154In addition, even when the wafer table WTB (wafer stage WST) or the liquid repellent plate 50 is provided with a mark for position measurement, or when the outer periphery of the liquid repellent plate 50 does not project outward from the wafer table WTB. Needless to say, the position information of the outer peripheral edge of the liquid repellent plate 50 may be acquired as described above.
0155Further, according to the exposure apparatus 100 of the present embodiment, the main controller 20 detects a part of the liquid repellent plate 50 using the alignment system ALG while measuring the position of the wafer table WTB using the interferometer system 118. At the same time, the position information of the inner peripheral edge of the opening 50a of the liquid repellent plate 50 is acquired based on the detection result and the measurement result of the corresponding interferometer system 118 (step 222). Therefore, it is possible to calculate the position and shape of the opening 50a based on the position information of the inner peripheral edge (see steps 224 and 226).
0156Further, in the exposure device 100 of the present embodiment, when the roundness of the main control device 20 is less than the second threshold value, for example, based on the position information of the inner peripheral edge of the opening 50a of the liquid repellent plate 50. , Wafer W is loaded onto the wafer holder WH in the opening 50a of the liquid repellent plate 50 on the wafer stage WST (wafer table WTB) via the transfer system 72 (step 232). Therefore, it is easier to load the wafer W into the opening 50a of the liquid repellent plate 50 on the wafer stage WST than when the information about the inner peripheral edge of the opening 50a of the liquid repellent plate 50 is not considered.
0157Further, in the exposure apparatus 100 of the present embodiment, when the positional relationship between the inner peripheral edge of the opening 50a and the object (tool wafer W1 or wafer W) in the opening 50a is acquired (see step 240), the main control device 20 When the wafer W is transferred to the wafer table WTB by the transfer system 72, at least one of the wafer table WTB and the transfer arm 70 of the transfer system 72 is controlled in consideration of the above positional relationship information, and the transfer arm 70 and the wafer are controlled. The wafer is loaded by adjusting the positional relationship with the table (see step 244). Therefore, based on this acquired positional relationship, the wafer can be loaded in the recess 140 of the wafer table WTB, that is, inside the inner peripheral edge of the opening 50a of the liquid repellent plate 50 in the desired positional relationship. Become. In this case, the outer peripheral edge of the wafer W and the inner peripheral edge of the liquid repellent plate 50a (the inner peripheral edge of the recess on the upper surface of the wafer table WTB) do not come into contact with each other, and the outer peripheral edge of the wafer W and the inner peripheral edge of the opening 50a Wafer W is placed on the wafer holder WH inside the inner peripheral edge of the opening 50a of the liquid repellent plate 50 above the wafer table WTB (inside the recess on the upper surface of the wafer table WTB) so that the distance between the wafers is smaller than a predetermined value, for example, 0.3 mm. It will be possible to load.
0158In the operation described with reference to FIGS. 11 and 12, the tool wafer W1 is placed on the wafer holder by providing a first threshold value and a second threshold value for the shape (roundness) of the opening 50a. , It may be determined whether or not to mount the tool wafer W1 by using only one threshold value. In this case, the tool wafer W1 may be a wafer having a diameter smaller than that of the wafer W to be exposed, or a wafer having a diameter substantially the same as that of the wafer W to be exposed.
0159Further, in the operations described with reference to FIGS. 11 and 12, the tool wafer W1 is placed on the wafer holder after the shape information of the opening 50a is acquired, but the acquisition of the shape information may be omitted. In this case as well, the tool wafer W1 may be a wafer having a diameter smaller than that of the wafer W to be exposed, or a wafer having a diameter substantially the same as that of the wafer W to be exposed.
0160Further, in the operations described with reference to FIGS. 11 and 12, the tool wafer W1 is placed on the wafer holder after the position information and shape information of the opening 50a are obtained, but the position information and shape information of the opening 50a are acquired. It is also possible to obtain the position information of the opening and the positional relationship (including the interval) between the inner peripheral edge of the opening and the outer peripheral edge of the tool wafer W1 after the tool wafer W1 is placed on the wafer holder. Of course, the shape information of the opening 50a can be acquired as needed. In this case, the tool wafer W1 is preferably a wafer having a diameter smaller than that of the wafer W to be exposed, but may be a wafer having substantially the same diameter as the wafer W to be exposed.
0161Further, in the operations described with reference to FIGS. 11 and 12, when the wafer W as the first substrate to be exposed is placed on the wafer holder, the positional relationship (interval) between the inner peripheral edge of the opening 50a and the wafer W. ) Is measured, but if the wafer W as the substrate to be exposed can be loaded at a predetermined position in the opening 50a based on the information obtained by using the tool wafer W1, the measurement operation () Steps 246, 248, 250) may be omitted.
0162Further, in the operation described with reference to FIGS. 11 and 12, in step 258, it is determined whether or not to replace the liquid repellent plate 50 after the exposure processing of one lot is completed, but step 258 is omitted. , The determination may be made at predetermined time intervals, or the liquid repellent plate may be replaced after a predetermined time elapses without determining the necessity of replacement.
0163Then, according to the exposure apparatus 100, the illumination light is applied to the wafer W placed inside the inner peripheral edge of the opening 50a of the liquid repellent plate 50 above the wafer table WTB (inside the recess on the upper surface of the wafer table WTB) as described above. Exposure is performed by irradiating IL (step 254). Therefore, it is possible to suppress the leakage of liquid (water) Lq between the wafer W and the liquid-repellent plate 50 during the exposure operation, and the immersion exposure provides high-resolution and a large depth of focus exposure compared to the air. By performing the above, the pattern of the reticle R can be transferred onto the wafer with high accuracy. For example, with ArF excimer laser light, it is possible to realize the transfer of a fine pattern of about 45 to 100 nm as a device rule.
0164According to the exposure apparatus 100 of the present embodiment, the wafer stage WST (wafer table WTB) needs only be provided with the minimum necessary components, such as a wafer holder, which are necessary for exposing the wafer. Therefore, the wafer stage WST It is possible to reduce the size and weight of the wafer stage, reduce the size of the drive mechanism (motor) that drives the wafer stage, and reduce the amount of heat generated by the motor, and suppress thermal deformation of the wafer stage WST and deterioration of exposure accuracy as much as possible. be able to.
0165In the above embodiment, a case where a plurality of measurement points are set on the outer peripheral edge of the liquid repellent plate 50 and the position information of the plurality of measurement points is acquired has been described, but the present invention is not limited to this, and for example, the liquid repellent plate. 50 A mark whose positional relationship with the outer peripheral edge is known is formed at a position inside the position of the outer peripheral edge on the upper surface, for example, a line-shaped mark parallel to the outer peripheral edge at a predetermined distance (referred to as D) from the outer peripheral edge. Then, at least one measurement point may be set on this mark, the position information of the measurement point may be measured, and the position of the outer peripheral edge may be acquired based on the measurement result and the distance D. As shown in FIG. 18, the liquid repellent plate 50 often has a curved surface (or slope) having a width d and a height h near the edge thereof, and the height h is about 0.1 mm. If the depth of focus of the system ALG is shallow, the edge image may be blurred. In such a case, the above line-shaped mark may be provided at a position where D> d, and the line-shaped mark may be imaged by the alignment system ALG. Of course, the mark is not limited to the above-mentioned line shape, and any shape may be used as long as the positional relationship with the outer peripheral edge is known.
0166Similarly, for the inner peripheral edge of the opening 50a of the liquid repellent plate 50, a mark whose positional relationship with the inner peripheral edge is known is formed in advance, and the position information of at least one measurement point on the mark is acquired. Is also good. For example, a circular line concentric with the opening 50a may be formed as a mark on the outer side of the inner peripheral edge of the opening 50a by a predetermined distance.
0167Further, when detecting the position information such as the outer peripheral edge of the liquid repellent plate 50, it is desirable to use the focus detection system of the alignment system ALG, but the detection beam of the focus detection system of the alignment system ALG deviates from the liquid repellent plate 50. In this case, after focusing once at a position where the detection beam can irradiate the surface of the liquid repellent plate 50, a so-called shift focus operation is performed in which the measurement point is positioned in the imaging field of view of the alignment system ALG while maintaining the focus state. It is desirable to do it.
0168Further, in the above embodiment, the outer peripheral edge of the liquid repellent plate 50, the inner peripheral edge of the opening 50a, the outer peripheral edge of the tool wafer W1 or the wafer W are imaged by using the alignment system ALG composed of the FIA type sensor, and the imaging thereof is performed. The case of acquiring the position information of each measurement point by the image processing method using the result has been described, but as the detection device, a sensor other than the FIA system, for example, a device for detecting reflected light or scattered light may be used. good. Further, when the FIA system is used, a method of detecting the reflected light from the object by epi-illumination may be used, of course, but the edge of the liquid repellent plate 50 is illuminated from below and the transmitted light is emitted from the liquid repellent plate 50. It is also possible to adopt a method of detecting above.
0169In the above-described embodiment, at least one of the replacement work of the liquid-repellent plate 50 and various measurements of the liquid-repellent plate 50 may be performed in a state where there is no liquid Lq on the image plane side of the projection optical system PL, or the measurement may be performed. The liquid Lq may be held between the table MTB and the projection optical system PL. When the liquid Lq is kept between the measurement table MTB and the projection optical system PL, the tip surface of the projection optical system PL can be kept wet, so that the occurrence of watermarks can be prevented. Instead, the work of total recovery and resupply of liquid Lq can be omitted.
0170Further, in the above embodiment, the wafer table WTB constitutes a first stage (and a moving body) on which a plate for detecting the position information of the outer peripheral edge thereof is detachably mounted, and the measurement stage MST is a second stage. The case where the above is configured has been described, but the present invention is not limited to this, and the measurement table MTB may constitute the first stage (and the moving body). That is, the position information of the outer peripheral edge of the plate detachably mounted on the measurement table MTB may be acquired. In this case, the movement of the measurement table MTB can be controlled based on the position information of the outer peripheral edge. In this case, at least one of the plate replacement work of the measurement table MTB and various measurements of the plate may be performed in a state where there is no liquid Lq on the image plane side of the projection optical system PL, or the wafer table WTB and the projection optical system PL. It may be executed while holding the liquid Lq between.
0171The replacement operation of the liquid repellent plate 50 of the wafer table WTB and the measurement operation of the outer peripheral edge of the liquid repellent plate 50 and the inner peripheral edge of the opening 50a of the liquid repellent plate 50 are performed between the measurement table MTB and the projection optical system PL. It may be executed while holding the liquid Lq.
0172That is, when the liquid repellent plate 50 is replaced on the wafer table WTB side, the position of the measurement table MTB is controlled so that the liquid Lq is located on the measurement table MTB as shown in FIG. 19 (A). .. Then, after the replacement of the liquid repellent plate 50 is completed, as shown in FIG. 19 (B), the outer peripheral edge of the measurement table MTB (measurement stage MST) side (+ Y side) of the liquid repellent plate 50 is aligned using the alignment system ALG. And measure. This makes it possible to bring the wafer table WTB (wafer stage WST) closer to the measurement table MTB (measurement stage MST).
0173Next, as shown in FIGS. 19 (C) and 19 (D), the outer peripheral edge of the liquid repellent plate 50 on the -X side and the outer peripheral edge of the liquid repellent plate 50 on the + X side are aligned using the alignment system ALG. Measure sequentially.
0174Based on the position information of the three points on the outer peripheral edge of the liquid repellent plate 50 measured in this way or the position information of the liquid repellent plate 50 obtained from this, the subsequent position management of the wafer table WTB (wafer stage WST) can be performed. This is done by the main controller 20.
0175Following the measurement of the position information of the outer peripheral edge of the liquid repellent plate 50 described above, for example, both stages WST are maintained in a state where the wafer table WTB (liquid repellent plate 50) and the measurement table MTB are in contact (or close to each other). , MST is moved integrally, and as shown in FIG. 20 (A), the inner peripheral edge of the opening 50a of the liquid repellent plate 50 on the + Y side is measured using the alignment system ALG. Next, while maintaining the state where the wafer table WTB (liquid repellent plate 50) and the measurement table MTB are in contact (or close to each other), both stages WST and MST are integrally moved in sequence, and FIGS. As shown in 20 (C), the inner peripheral edge on the -X side and the inner peripheral edge on the + X side of the opening 50a of the liquid repellent plate 50 are sequentially measured using the alignment system ALG. In this case, since the wafer is not placed on the wafer table WTB, the liquid Lq cannot be positioned at the portion where the wafer is placed, but it is shown in FIGS. 20 (A) to 20 (C). As described above, since the inner peripheral edge can be measured, the wafer can be loaded on the wafer holder WH in the same manner as in the above embodiment based on the measurement result.
0176As described above, the replacement operation of the liquid repellent plate 50 of the wafer table WTB and the measurement operation of the outer peripheral edge of the liquid repellent plate 50 and the inner peripheral edge of the opening 50a of the liquid repellent plate 50 are performed with the measurement table MTB and the projection optical system PL. By executing the liquid Lq while holding the liquid Lq between the two, the liquid recovery operation and the liquid supply operation become unnecessary, the time required for these operations becomes unnecessary, and the throughput of the exposure process can be improved accordingly.
0177As described above, the outer peripheral edge of the liquid repellent plate 50 and the inner peripheral edge of the opening 50a are measured, and after the wafer is loaded on the wafer holder WH, the wafer stage WST (wafer table WTB) on which the wafer is loaded is repelled. The range of movement in the state where the liquid plate 50 and the measurement stage MST are in contact with each other is expanded. That is, the liquid Lq can be positioned on the entire surface of the wafer table WTB. Therefore, the measurement may be performed again using the measurement method according to the flowcharts of FIGS. 7, 11 and 12 described in the above embodiment. This makes it possible to perform more accurate measurement.
0178Further, in the above embodiment, the measurement points of the position information are located at a plurality of pairs symmetrical with respect to the center of each of the outer peripheral edge of the liquid repellent plate 50, the inner peripheral edge of the opening 50a, the tool wafer W1 or the outer peripheral edge of the wafer W. The case where the setting is made has been described, but this is merely the case where, for example, when calculating the position of each center point, in anticipation of improvement in measurement accuracy due to the averaging effect, the present invention provides this. Of course, it is not limited to.
0179Further, in the above embodiment, the case where the shape of the liquid repellent plate 50 is substantially square and the opening 50a is circular has been described, but the shape of the plate may be circular, polygonal or other shapes, and the opening may also be treated. Any shape may be used as long as it corresponds to the shape of the object. For example, when a liquid crystal display element or the like is an object to be processed, the opening may be rectangular according to the shape of the glass plate which is the object to be processed.
0180Further, in the above-described embodiment, the case where the plate 50 can be attached to and detached from the wafer table WTB has been described, but the plate 50 may be integrally formed with the wafer table WTB. Also in this case, for example, the position information of the inner peripheral edge of the recess formed for placing the wafer W on the wafer table WTB can be detected as shown in FIGS. 11 and 13.
0181Further, in the above-described embodiment, a series of operations including the measurement of the position information of the outer peripheral edge of the plate described with reference to FIG. 7 and the measurement of the position information of the inner peripheral edge of the opening of the plate described with reference to FIG. 11 The series of operations including the above does not necessarily have to be performed together, and only one of them can be performed.
0182In the above embodiment, the case where the present invention is applied to the immersion exposure apparatus has been described, but the scope of application of the present invention is not limited to this, and a normal scanning stepper which is not an immersion type or the like is used. Also, the present invention can be suitably applied. In this case, instead of the liquid-repellent plate, a plate having no liquid-repellent surface formed on its surface can be used.
0183Further, in the above embodiment, the case where the stage device includes one wafer stage and one measurement stage has been described, but the present invention is not limited to this, and at least a wafer stage that holds a wafer without providing a measurement stage is provided. One may be provided. When a plurality of wafer stages are provided, at least one of the plate replacement work and the various plate measurement work on one wafer stage is performed in a state where there is no liquid Lq on the image plane side of the projection optical system PL. Alternatively, the other wafer stage may be placed under the projection optical system PL (on the image plane side), and the liquid Lq may be held between the projection optical system and the other wafer stage. ..
0184Further, in the above embodiment, the case where the leveling table 52 has 6 degrees of freedom and the measurement table MTB has 3 degrees of freedom has been described, but the present invention is not limited to this, and the leveling table 52 has 3 degrees of freedom and the measurement table MTB has 3 degrees of freedom. A configuration having three degrees of freedom may be adopted. Further, it is also possible to adopt a configuration in which the measurement table MTB has 6 degrees of freedom without providing the leveling table 52.
0185In the above embodiment, pure water (water) is used as the liquid, but it goes without saying that the present invention is not limited to this. As the liquid, a chemically stable liquid having a high transmittance of illumination light IL and a safe liquid, for example, a fluorine-based inert liquid may be used. As the fluorine-based inert liquid, for example, Fluorinert (trade name of 3M, Inc., USA) can be used. This fluorine-based inert liquid is also excellent in terms of cooling effect. Also, use a liquid that is transparent to the illumination light IL, has a high refractive index as much as possible, and is stable to the photoresist applied to the projection optical system or the wafer surface (for example, cedar oil). You can also do it. Also, F<sub>2</sub>When using a laser as a light source, von Bryn oil may be selected.
0186Further, in the above embodiment, the recovered liquid may be reused. In this case, it is desirable to provide a filter for removing impurities from the recovered liquid in the liquid recovery device, the recovery pipe, or the like. ..
0187In the above embodiment, the optical element on the image plane side of the projection optical system PL is assumed to be the tip lens 91, but the optical element is not limited to the lens, and the optical characteristics of the projection optical system PL are not limited to the lens. For example, it may be an optical plate (parallel flat plate, etc.) used for adjusting aberrations (spherical aberration, coma, etc.), or it may be a simple cover glass. The optical element on the most image plane side of the projection optical system PL (tip lens 91 in each of the above embodiments) is a liquid (adhesion of scattered particles generated from the resist or impurities in the liquid due to irradiation with the illumination light IL). In each of the above embodiments, the surface may become dirty due to contact with water). Therefore, the optical element may be detachably (replaceable) fixed to the lowermost portion of the lens barrel 40 and may be replaced regularly.
0188In such a case, if the optical element that comes into contact with the liquid is a lens, the cost of the replacement part is high and the time required for replacement becomes long, resulting in an increase in maintenance cost (running cost) and a decrease in throughput. .. Therefore, the optical element that comes into contact with the liquid may be, for example, a parallel flat plate that is cheaper than the lens 91.
0189Further, in the above embodiment, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described, but it goes without saying that the scope of application of the present invention is not limited to this. That is, the present invention can be applied to a step-and-repeat projection exposure apparatus, a step-and-stitch exposure apparatus, a proximity exposure apparatus, and the like.
0190The application of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern onto a square glass plate, an organic EL, a thin film magnetic head, and an image pickup device. It can be widely applied to exposure equipment for manufacturing (CCD, etc.), micromachines, DNA chips, and the like. Further, in order to manufacture reticle or mask used not only in microdevices such as semiconductor elements but also in optical exposure equipment, EUV exposure equipment, X-ray exposure equipment, electron beam exposure equipment and the like, glass substrates or silicon wafers and the like are used. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a wafer.
0191The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser, but is a KrF excimer laser (output wavelength 248 nm), F.<sub>2</sub>Laser (output wavelength 157 nm), Ar<sub>2</sub>Laser (output wavelength 126 nm), Kr<sub>2</sub>It is also possible to use a pulsed laser light source such as a laser (output wavelength 146 nm) or an ultrahigh pressure mercury lamp that emits bright lines such as g-line (wavelength 436 nm) and i-line (wavelength 365 nm). Further, a harmonic generator of a YAG laser or the like can also be used. In addition, a single-wavelength laser beam in the infrared or visible region oscillated from a DFB semiconductor laser or fiber laser is amplified by a fiber amplifier doped with, for example, erbium (or both erbium and itterbium), and a nonlinear optical crystal is used. You may use a harmonic whose wavelength is converted into ultraviolet light by using. Further, the projection optical system may be not only a reduction system but also an equal magnification system and an enlargement system.
0192Further, in the above-described embodiment, an exposure device using a light-transmitting mask (reticle) in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate has been described. Instead, for example, as disclosed in US Pat. No. 6,778,257, an electronic mask (variable molding mask) that forms a transmission pattern, a reflection pattern, or a light emission pattern based on the electronic data of the pattern to be exposed is used. It is also possible to apply the present invention to the exposure apparatus used.
0193In addition, as disclosed in International Publication No. 2001/035168, it is also used in an exposure apparatus (lithography system) that forms a line-and-space pattern on a wafer W by forming interference fringes on the wafer W. The present invention can also be applied.
0194In the above embodiment, the case where the position measurement method, the measurement method, the loading method, and the like of the present invention are applied to the exposure apparatus has been described, but the present invention is not limited to this, and the position measurement method of the present invention has a predetermined shape. It can be applied to any device provided with a moving body in which the plate is detachably mounted on the moving body, and the measuring method, loading method, etc. of the present invention have an opening for placing an object. It can be applied as long as the plate is a device equipped with a detachably mounted moving body.
0195The semiconductor device is formed on a mask by a step of designing the function and performance of the device, a step of manufacturing a reticle based on this design step, a step of manufacturing a wafer from a silicon material, and an exposure apparatus of the above embodiment. It is manufactured through a lithography step of transferring a pattern onto a photosensitive object, a device assembly step (including a dicing step, a bonding step, and a packaging step), an inspection step, and the like. In this case, since the exposure apparatus of the above embodiment and the exposure method thereof are used in the lithography step, highly accurate exposure can be realized over a long period of time. Therefore, it is possible to improve the productivity of the highly integrated microdevice in which the fine pattern is formed.
0196As described above, the exposure apparatus and exposure method of the present invention and the device manufacturing method are suitable for manufacturing microdevices such as semiconductor elements.
019720 ... Main controller, 50 ... Liquid repellent plate, 50a ... Aperture, 70 ... Conveyor arm, 100 ... Exposure device, 101 ... Plate, 118 ... Interferometer system, 132 ... Immersion mechanism, WST ... Wafer stage, MST ... Measurement stage, ALG ... Alignment system, W ... Wafer.
20 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8 Sheet 9 Sheet 10 Sheet 11 Sheet 12 Sheet 13 Sheet 14 Sheet 15 Sheet 16 Sheet 17 Sheet 18 Sheet 19 Sheet 20
Every citation, both ways
| Document | Relation | Office |
|---|---|---|
| WO2004053955A1 | Cites | World Intellectual Property Organization (WIPO) |
| JP2000164504A | Cites | Japan |
| JP10199804A | Cites | Japan |
| JP2000133589A | Cites | Japan |
| WO2004090577A2 | Cites | World Intellectual Property Organization (WIPO) |
123 members in 10 offices
Priority claims2
| Document | Office | Kind | Date |
|---|---|---|---|
| 2004335050 | Japan | – | |
| 2004335050 | Japan | A |
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| EP1821336A1 | European Patent Office (EPO) | A1 | |
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Numbers
- Publication
- 6399321
- Application
- 96125
Titles2
- Japanese
- 露光装置及び露光方法、並びにデバイス製造方法
- English
- Exposure equipment and exposure method, and device manufacturing method
Classification
- CPC, 10
- G03F7/70341
- G03F7/70775
- G03F7/70691
- G03F7/707
- G03F9/7011
- G03F9/7088
- G03F7/70725
- Y10T29/49002
- G03F7/70975
- G03F7/2041
- IPC, 5
- G03F7 20
- H01L21 68
- G01B11 00
- H10P72 30
- H10P72 50
