Lithographic apparatus and device manufacturing method
13 claims: 8 independent, 5 dependent
- 1リソグラフィ装置であって 、 基 板を保持する基板テーブルと、 パ ターン形成された放射ビーム を投 影する投影系と、 前記投影系と前記基板との間の空間の少なくとも一部に液体を充満する液体供給システムと、 前記投影系と前記基板との間の前記空間の内部に前記液体を実質的に閉じ込める封止部材と、 前記液体供給システムによって供給された液体の正味蒸発率を制御する液体蒸発制御装置と、 前記封止部材の境界によって一側を区切られ且つ前記基板によって第2の側を区切られた間隙を介して前記封止部材から逃げる液体の量を制御する、気体源に連結された気体シールとを備え、 前記液体蒸発制御装置が、前記液体の前記正味蒸発率を制御する目的で10%よりも大きい制御された相対湿度を有する気体を 前記気体シールに 供給するために、前記気体源と相互作用して、前記気体源によって 前記気体シールに 供給された前記気体の相対湿度を調整する気体湿度制御装置を備えることを特徴とするリソグラフィ装置。
- 2請求項1に記載のリソグラフィ装置において、前記気体湿度制御装置は、一定流量で湿度制御された気体の流れを生成し、さらに、前記気体源は気体シール流量制御装置を備え、当該気体シール制御装置が、前記一定の流れを前記気体湿度制御装置から受け取り、且つ前記気体湿度制御装置によって供給された前記一定の流れの一部を選択的に外部貯槽に排出することによって前記気体シールへの気体の流量を変更する、リソグラフィ装置。
- 3請求項1に記載のリソグラフィ装置において、前記気体湿度制御装置は気体流を制御された範囲まで加湿する加湿部分を含み、前記加湿部分は、 相対的に乾燥した気体流を受け取り、少なくとも1つの液槽から蒸発した液体蒸気によって前記気体流の少なくとも一部を加湿する蒸発容器と、 前記蒸発容器の温度よりも実質的に低い温度に保持され、完全に飽和した気体流を得るために、前記少なくとも一部が加湿された気体流を冷却する冷却容器と、を備える、リソグラフィ装置。
- 4請求項3に記載のリソグラフィ装置において、前記加湿部分は、凝縮容器の飽和気体出力に連結可能な乾燥気体源をさらに備え、前記気体湿度制御装置は、制御された相対湿度水準を有する気体流を得るために、乾燥気体が前記凝縮容器から出力された飽和気体の流れと混合される率を調整できる、リソグラフィ装置。
- 5請求項1乃至4の何れかに記載のリソグラフィ装置において、前記気体源は、前記気体シールに供給された前記気体の温度を制御するために前記気体源を制御する気体温度制御装置を備え、前記シールに進入する前の前記気体の温度は、前記基板の平均温度よりも高くなるように設定されている、リソグラフィ装置。
- 6請求項5に記載のリソグラフィ装置において、前記気体シールに進入する前の前記気体の温度は、前記基板の平均温度よりも1Kから5K高くなるように設定されている、リソグラフィ装置。
- 7請求項1乃至 6 の何れかに記載のリソグラフィ装置において、前記気体源は、40%よりも大きな相対湿度を有する気体を供給する、リソグラフィ装置。
- 8請求項1乃至 7 の何れかに記載のリソグラフィ装置において、前記リソグラフィ装置は、 前記基板、前記基板テーブル及び基板保持器の少なくとも1つの少なくとも一部の温度を計測する少なくとも1つの温度センサをさらに備え、 前記気体湿度制御装置は、前記少なくとも1つの温度センサによって計測された1つ以上の温度と少なくとも1つの標的温度との間の1つ以上の差を縮小するように、前記気体源によって 前記気体シールに 供給された前記気体の相対湿度を調整することができる、リソグラフィ装置。
- 9請求項1乃至 8 の何れかに記載のリソグラフィ装置において、前記液体蒸発制御装置は、前記基板と前記投影系の最終要素との間の前記封止部材の外部領域に10%よりも大きい制御された相対湿度を有する気体を供給する気体シャワー放出口をさらに備えている、リソグラフィ装置。
- 10請求項 9 に記載のリソグラフィ装置において、前記気体シャワー放出口は40%から50%の範囲内の相対湿度を有する気体を供給する、リソグラフィ装置。
- 11請求項 9 又は 10 に記載のリソグラフィ装置において、前記リソグラフィ装置は、前記基板、前記基板テーブル及び基板保持器の少なくとも1つの少なくとも一部の温度を計測する少なくとも1つの温度センサと、 前記少なくとも1つの温度センサによって計測された1つ以上の温度と少なくとも1つの標的温度との間の1つ以上の差を縮小するように、前記気体シャワー放出口によって供給された前記気体の相対湿度を調整できる気体シャワー放出口制御装置と、をさらに備えている、リソグラフィ装置。
- 12請求項1乃至 11 の何れかに記載のリソグラフィ装置において、前記リソグラフィ装置は、 前記気体源が10%よりも大きい制御された相対湿度を有する気体を供給し、 前記基板と前記投影系の最終要素との間の前記封止部材の外部領域に、前記気体源によって供給された前記気体の湿度と実質的に等しい制御された相対湿度を有する気体を供給する気体シャワー放出口をさらに備えている、リソグラフィ装置。
- 13デバイス製造方法であって 、 基 板を保持する基板テーブルを提供する工程と、 パ ターン形成された放射ビーム を投 影する投影系を提供する工程と、 前記投影系と前記基板との間の空間の少なくとも一部に液体を充満する液体供給システムを提供する工程と、 前記投影系と前記基板との間の前記空間の内部に前記液体を実質的に閉じ込める封止部材を提供する工程と、 前記液体供給システムによって供給された液体の正味蒸発率を制御する工程と、 前記封止部材の境界によって一側を区切られ且つ前記基板によって第2の側を区切られた間隙を介して前記封止部材から逃げる液体の量を制御し、気体源に連結された気体シールを提供する工程と、を有し 前記液体蒸発制御装置が、前記液体の前記正味蒸発率を制御する目的で10%よりも大きい制御された相対湿度を有する気体を 前記気体シールに 供給するために、前記気体源と相互作用して、前記気体源によって 前記気体シールに 供給された前記気体の相対湿度を調整する気体湿度制御装置を備えることを特徴とするデバイス製造方法。
Independent claims13
100 paragraphs, as filed
The present invention relates to a lithography apparatus and a device manufacturing method.
A lithographic device is a machine that applies a desired pattern on a substrate, usually on a target portion of the substrate. Lithographic equipment can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a pattern forming apparatus, also called a mask or reticle, can be used to create a circuit pattern to be formed on each layer of the IC. Such patterns can be transferred onto a target portion (eg, including a portion of one or several dies) on a substrate (eg, a silicon wafer). The transfer of the pattern is generally performed by imaging on a radiation-sensitive material (resist) layer provided on the substrate. Generally, a single substrate contains a reticulated pattern of adjacent target portions that are continuously exposed. Known lithographic devices include a so-called stepper, which irradiates each target portion by exposing the entire pattern onto the target portion in a single operation, and a radiation beam that exposes the pattern in a given direction (scanning direction). Included are so-called scanners that scan and, on the other hand, illuminate each target portion by scanning the substrate synchronously in parallel or antiparallel in this direction. It is also possible to transfer the pattern from the pattern forming apparatus to the substrate by applying the pattern onto the substrate.
It is proposed to immerse the substrate in a liquid with a relatively large index of refraction (eg, water) in a lithographic projection device to fill the space between the final element of the projection system and the substrate. It has been. The point is that the exposed radiation has a shorter wavelength in the liquid so that finer features can be imaged. (The effect of the liquid is also thought to increase the effective numerical aperture of the system and also the depth of focus.) Other immersions, including water in which solid particles (eg, quartz) are turbid, are also proposed. It has been.
However, immersing the substrate or substrate and the substrate table in a liquid tank (see, eg, US Pat. No. 4,509,852, which is hereby incorporated by reference in its entirety) accelerates during scan exposure. It means that there is a large amount of liquid that must be present. This requires additional or more powerful motors, and turbulence in the liquid can have unnecessary and unpredictable effects.
One of the proposed solutions is for the liquid supply system to use a liquid confinement system to supply the liquid only on the local area of the substrate and between the final element of the projection system and the substrate. (The substrate generally has a larger surface area than the final element of the projection system). One method proposed for such an arrangement is disclosed in Pamphlet International Publication No. 99/49504, which is hereby incorporated by reference in its entirety. As illustrated in FIGS. 2 and 3, at least one liquid is fed onto the substrate by at least one inlet IN, preferably along the direction of movement of the substrate with respect to the final element, and after passing below the projection system. Removed by outlet OUT. That is, when scanning the substrate below the element in the -X direction, the liquid is supplied on the + X side of the element and removed on the -X side. FIG. 2 is a diagram schematically showing an arrangement in which the liquid is supplied through the inlet IN and removed on the other side of the element by the outlet OUT connected to the low pressure source. In the example of FIG. 2, the liquid is supplied along the direction of movement of the substrate with respect to the final element, but this does not have to be the case. Various orientations and numbers of inlets and outlets positioned around the final element are possible, one embodiment shown in FIG. 3, where there are four sets of inlets with outlets on both sides. Is provided in a regular fashion around the final element.
Another proposed solution is to provide such a liquid supply system with a sealing member that extends along at least part of the boundary in the space between the final element of the projection system and the substrate table. .. Such a solution is illustrated in FIGS. 4a and 4b. This sealing member may have some relative movement in the Z direction (optical axis direction), but is substantially stationary with respect to the projection system in the XY plane. The sealing is formed between the sealing member and the surface of the substrate. This sealing is preferably a non-contact sealing such as a gas seal. A system having such a gas seal is disclosed in European Patent Application No. 03252955.4, which is hereby incorporated by reference in its entirety.
FIG. 4b shows an exemplary arrangement of the sealing member 12 configured to confine the immersion liquid within the local area 25 below the projection lens PL. The sealing member 12 is provided with an extractor EX configured to extract the liquid from the local region 25 via the gauze GZ. This extractor EX can extract both liquid and gas or only gas. The recess RE is provided on the radial outside of the extractor EX, and the gas seal 27 is further provided on the radial outside of the recess RE. The gas seal 27 forms a gas jet JE used to dry the surface of the substrate W and / or reduce the amount of liquid escaping from the sealing member 12.
European Patent Application Publication No. 03257072.3 discloses the idea of a dual-stage or dual-stage immersion lithography system. Such a device is provided with two stages for supporting the substrate. In the absence of immersion, the stage in the first position is used to perform horizontal measurements, while in the presence of immersion, the stage in the second position is used to perform the exposure. .. Alternatively, the device has only one stage.
Immersion introduction increases resolution, but includes alignment errors (ie, overlay errors), defocusing, and aberrations between one layer and the next in the image created on the substrate. Is known to cause errors.
<p> It is desirable to provide a system that reduces lithography errors due to immersion liquid.</p>
<p> According to one aspect of the present invention, the lithographic apparatus is an illumination system configured to adjust the radiated beam and a pattern capable of imparting a pattern to the cross section of the radiated beam in order to form a patterned radiated beam. A support configured to support the forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned radiation beam onto a target portion of the substrate. A liquid supply system configured to fill at least a portion of the space between the final element of the projection system and the substrate and the space between the final element of the projection system and the substrate. A lithography apparatus including a sealing member arranged so as to substantially confine the liquid inside, and a liquid evaporation control device arranged to control the net evaporation rate of the liquid supplied by the liquid supply system. Is provided.</p><p> According to another aspect of the present invention, a lithography apparatus can apply a pattern to an illumination system configured to adjust a radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A support configured to support the pattern forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned radiation beam onto a target portion of the substrate. A liquid supply system configured to fill at least a part of the space between the final element of the projection system and the substrate, and the space between the final element of the projection system and the substrate. A sealing member arranged so as to substantially confine the liquid inside the substrate, and the substrate table is moved with respect to the sealing member along a predetermined scanning path, whereby the substrate is moved over the entire surface of the substrate. A substrate table scanning system arranged to scan a target portion and at least one of the substrate table's position, velocity, acceleration, and scanning path with respect to the encapsulant, local substrate temperature, and local substrate table temperature. A lithography apparatus is provided that includes a substrate heater configured to heat at least a portion of the substrate.</p><p> According to another aspect of the invention, the lithography apparatus can impart a pattern to the cross section of the emission beam to form a patterned emission beam with an illumination system configured to adjust the emission beam. A support configured to support the pattern forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned emission beam onto a target portion of the substrate. A liquid supply system configured to fill at least a portion of the space between the final element of the projection system and the substrate, and the space between the final element of the projection system and the substrate. The seal is provided through a gap between a sealing member arranged so as to substantially confine the liquid inside the gas, and a gap separated by a boundary between the sealing members on one side and a second side by the substrate. It comprises a gas seal configured to control the amount of liquid escaping from the stop member, the gas seal being supplied by a gas inlet and the gas inlet to supply gas to a region inside the gap. A vacuum discharge port for removing gas from the region inside the gap is provided, and the gas injection port and the vacuum discharge port are provided in a gas injection port tube and a vacuum discharge port tube embedded in the sealing member. A lithography apparatus is provided in which the sealing members are connected to each other and the sealing member further includes a sealing member temperature stabilizer.</p><p> According to another aspect of the present invention, a lithographic apparatus can impart a pattern to an illumination system configured to adjust the radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A support configured to support the pattern forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned radiation beam onto a target portion of the substrate. A liquid supply system configured to fill at least a portion of the space between the final element of the projection system and the substrate, and the space between the final element of the projection system and the substrate. Controls the temperature and flow rate of the sealing member arranged so as to substantially confine the liquid inside the substrate and the heat exchange fluid arranged so as to flow through the network structure of the flow path embedded in the substrate table. A lithographic apparatus is provided that comprises a substrate table heat exchange fluid control device for the purpose.</p><p> According to another aspect of the present invention, the lithography apparatus can impart a pattern to the cross section of the radiated beam in order to form the illuminating system configured to adjust the radiated beam and the patterned radiated beam. A support configured to support the pattern forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned radiation beam onto a target portion of the substrate. The substrate table comprises at least one integrated local temperature control system comprising a temperature sensor coupled with a heater, wherein the heater has a local temperature measured by the temperature sensor below a predetermined reference value. Provided is a lithography apparatus configured to generate heat as it descends and to stop generating heat when the local temperature rises above the predetermined reference value.</p><p> According to another aspect of the present invention, a lithography apparatus can apply a pattern to an illumination system configured to adjust a radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A support configured to support the pattern forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned radiated beam onto a target portion of the substrate. And at least one temperature sensor configured to measure the temperature of at least one or more of the substrate, the substrate table, and the substrate cage, and the at least one temperature sensor. Provided is a lithography device including a projection system control device configured to adjust the characteristics of the patterned radiation beam in response to the one or more temperatures.</p><p> According to another aspect of the present invention, a lithography apparatus can apply a pattern to an illumination system configured to adjust a radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A support configured to support the pattern forming apparatus, a substrate table configured to hold the substrate, and a projection system configured to project a patterned radiation beam onto a target portion of the substrate. A liquid supply system configured to fill at least a part of the space between the final element of the projection system and the substrate, and the space between the final element of the projection system and the substrate. A sealing member arranged so as to substantially confine the liquid inside the substrate, and the substrate table is moved with respect to the sealing member along a predetermined path, whereby the target is spread over the entire surface of the substrate. Provided is a lithography apparatus including a substrate table displacement system arranged so as to move a portion, and a microwave source and a microwave confinement device configured to jointly apply heat to a liquid on the surface of the substrate. Will be done.</p><p> According to another aspect of the present invention, there is a device manufacturing method of providing an illumination system configured to adjust the radiated beam and a radiated beam to form a patterned radiated beam. A step of providing a support configured to support a pattern forming apparatus capable of imparting a pattern to a cross section, a step of providing a substrate table configured to hold a substrate, and a process of providing a patterned radiated beam to a substrate. A step of providing a projection system configured to project onto a target portion of the projection system and a liquid supply configured to fill at least a portion of the space between the final element of the projection system and the substrate. A step of providing a system, a step of providing a sealing member arranged so as to substantially confine the liquid inside the space between the final element of the projection system and the substrate, and the liquid supply system. A device manufacturing method comprising controlling the net evaporation rate of the liquid supplied by the device is provided.</p><p> According to another aspect of the present invention, there is a device manufacturing process that provides a step of providing an illumination system configured to adjust the radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A step of providing a support configured to support a pattern forming apparatus capable of imparting a pattern to the substrate, a step of providing a substrate table configured to hold the substrate, and a patterned radiation beam of the substrate. A process of providing a projection system configured to project onto a target portion and a liquid supply system configured to fill at least a portion of the space between the final element of the projection system and the substrate. And a step of providing a sealing member arranged so as to substantially confine the liquid inside the space between the final element of the projection system and the substrate, and along a predetermined path. A step of providing a substrate table displacement system in which the substrate table is moved relative to the sealing member, thereby moving the target portion over the entire surface of the substrate, and the substrate with respect to the sealing member. A device manufacturing method is provided that includes a step of heating at least one of the table positions, speeds, accelerations, and predetermined paths, a local substrate temperature, and at least a portion of the substrate according to the local substrate table temperature.</p><p> According to another aspect of the invention, a device manufacturing method comprising providing an illumination system configured to adjust the radiated beam of the radiated beam to form a patterned radiated beam. A patterned radiating beam comprising providing a support configured to support a pattern forming apparatus capable of imparting a pattern to a cross section and providing a substrate table configured to hold the substrate. Includes the step of providing a projection system configured to project the gas onto a target portion of the substrate, and is configured to fill at least a portion of the space between the final element of the projection system and the substrate with a liquid. Including a step of providing a liquid supply system, and including a step of providing a sealing member arranged so as to substantially confine the liquid inside the space between the final element of the projection system and the substrate. Provided is a gas seal configured to control the amount of liquid escaping from the sealing member through a gap separated by a boundary of the sealing member on one side and separated by a substrate on the second side. Provided is a gas seal including a gas injection port capable of supplying a gas to a region inside the gap and a vacuum discharge port capable of removing the gas supplied by the gas injection port from the region inside the gap. The gas injection port and the vacuum discharge port are connected to the gas injection tube and the vacuum discharge port tube embedded in the sealing member, respectively, and further, a step of stabilizing the temperature of the sealing member. Device manufacturing methods are provided, including.</p><p> According to another aspect of the invention, there is a process of manufacturing a device that provides an illumination system configured to adjust the radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A step of providing a support configured to support a pattern forming apparatus capable of imparting a pattern to the substrate, a step of providing a substrate table configured to hold the substrate, and a patterned radiation beam of the substrate. A process of providing a projection system configured to project onto a target portion and a liquid supply system configured to fill at least a portion of the space between the final element of the projection system and the substrate. And a step of providing a sealing member arranged so as to substantially confine the liquid inside the space between the final element of the projection system and the substrate, and in the substrate table. Provided is a device manufacturing method including a step of providing a network structure of a flow path embedded in the flow path and a step of controlling the temperature and flow rate of a heat exchange fluid arranged so as to flow through the network structure of the flow path. To.</p><p> According to another aspect of the invention, there is a process of manufacturing a device that provides an illumination system configured to adjust the radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A step of providing a support configured to support a pattern forming apparatus capable of imparting a pattern to the substrate, a step of providing a substrate table configured to hold the substrate, and a patterned radiation beam of the substrate. The substrate table comprises at least one integrated local temperature control system with a temperature sensor coupled to the heater, comprising the steps of providing a projection system configured to project onto a target portion, said heater. Is configured to generate heat when the local temperature measured by the temperature sensor falls below a predetermined reference value, and to stop generating heat when the local temperature rises above the predetermined reference value. The device manufacturing method is provided.</p><p> According to another aspect of the invention, there is a process of manufacturing a device that provides an illumination system configured to adjust the radiated beam and a cross section of the radiated beam to form a patterned radiated beam. A step of providing a support configured to support a pattern forming apparatus capable of imparting a pattern to the substrate, a step of providing a substrate table configured to hold the substrate, and a patterned radiation beam of the substrate. A step of providing a projection system configured to project onto a target portion and measuring the temperature of at least one or more of the substrate, the substrate table, and the substrate cage. A device comprising providing at least one temperature sensor and adjusting the characteristics of the patterned radiated beam in response to the one or more temperatures measured by the at least one temperature sensor. A manufacturing method is provided.</p><p> According to another aspect of the invention, there is a process of manufacturing a device that provides an illumination system configured to adjust the radiated beam and a section of the radiated beam to form a patterned radiated beam. A step of providing a support configured to support a pattern forming apparatus capable of imparting a pattern to the substrate, a step of providing a substrate table configured to hold the substrate, and a patterned radiation beam of the substrate. A process of providing a projection system configured to project onto a target portion and a liquid supply system configured to fill at least a portion of the space between the final element of the projection system and the substrate. And a step of providing a sealing member arranged so as to substantially confine the liquid inside the space between the final element of the projection system and the substrate, and along a predetermined path. To provide a substrate table displacement system arranged to move the substrate table relative to the sealing member, thereby moving the target portion over the entire surface of the substrate, and on the surface of the substrate. A method comprising the steps of using a microwave source and a microwave confinement device to apply heat to the liquid.</p><p> Here, an embodiment of the present invention will be described only as an example with reference to the accompanying drawings showing the corresponding parts of the corresponding reference numerals.</p>
FIG. 1 schematically shows a lithography apparatus according to a specific embodiment of the present invention. This device An illumination system (illuminator) IL configured to adjust the projected beam B (eg, ultraviolet or far-ultraviolet). A support structure (eg, a mask) that is coupled to a first positioning device PM that is made to support the pattern forming device (eg, mask) MA and is configured to accurately position the pattern forming device according to some parameters. For example, mask table) MT and A substrate table (eg, a substrate table) made to hold a substrate (eg, a resist coated wafer) W and coupled to a second positioning means PW configured to accurately position the substrate according to some parameters (eg, a resist coated wafer). Wafer table) WT and A projection system (eg, a refraction projection lens) configured to project a pattern applied to the radiation beam B by the pattern forming apparatus MA onto a target portion C (eg, including one or more dies) of the substrate W. System) PS and.
Lighting systems are various types of optics for inducing, shaping, or controlling radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optics, or The combination may be included.
The support structure supports the pattern forming apparatus (ie, supports its weight). It holds the pattern forming apparatus in an manner depending on the orientation of the pattern forming apparatus, the design of the lithographic apparatus, and other conditions such as whether or not the pattern forming apparatus is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the pattern forming apparatus. The support structure may be, for example, a gantry or table that can be fixed or movable as required. This support structure can secure the pattern forming means at a desired position with respect to the projection system, for example. Any use of the terms "reticle" or "mask" herein can be considered synonymous with the more general term "pattern forming apparatus".
As used herein, the term "pattern forming apparatus" is broadly understood to refer to an apparatus that can be used to impart a pattern to the cross section of a radiated beam, such as forming a pattern within a target portion of a substrate. It should be. It should also be noted that the pattern applied to the radiated beam may not exactly correspond to the desired pattern in the target portion of the substrate (eg, if the pattern contains phase shift characteristics or so-called auxiliary characteristics). In general, the pattern imparted to the radiated beam will correspond to a particular functional layer in the device created in the target portion, such as an integrated circuit.
The pattern forming apparatus can be a transmissive type or a reflective type. Examples of pattern forming equipment include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include not only types such as binary masks, Levenson phase shift masks, and halftone phase shift masks, but also various composite mask types. One embodiment of a programmable mirror array uses a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incident radiating beam in different directions. The tilted mirror imparts a pattern in the radiated beam reflected by the mirror matrix.
As used herein, the term "projection system" is used to include refractive, reflective, reflective-refractive, magnetic, electromagnetic, and electrostatic optical systems, and any combination thereof. It should be broadly construed as including any kind of projection system suitable for exposure radiation or for other factors such as the use of immersion liquid or the use of vacuum. Any use of the term "projection lens" herein can be considered synonymous with the more general term "projection system".
As illustrated here, the device is transmissive (eg, using a transmissive mask). Alternatively, the device may be reflective (eg, using the type of programmable mirror array or reflective mask mentioned above).
The lithographic apparatus can be of a type having two or more substrate tables (and / or two or more mask tables). In such a "multistage" machine, additional tables can be used in parallel. That is, a preliminary step can be performed on one or more tables while one or more tables are being used for exposure. The substrate W can be held directly by the substrate table WT (sometimes called a mirror block) or by a substrate cage (sometimes called a bur plate or chuck), which cage is then It is held by the board table WT.
Referring to FIG. 1, the illuminator IL receives a radiated beam from the source SO. The radiation source and the lithographic apparatus are separate entities, for example, when the radiation source is an excimer laser. In such cases, the source is not considered to form part of the lithography equipment and the radiated beam is, for example, with the assistance of a beam delivery system BD including a suitable induction mirror and / or beam expander. It is sent from the radiation source SO to the illuminator IL. In other cases, for example, when the source is a mercury lamp, the source may form part of a lithographic device. The radiation source SO and the illuminator IL can be referred to as the radiation system together with the beam transmission system BD (if necessary).
The illuminator IL can be equipped with a regulator AD for adjusting the angular intensity distribution of the radiated beam. In general, at least the outer radius range and / or the inner radius range (usually referred to as σ-outer and σ-inner) of the intensity distribution in the pupil plane of the illuminator can be adjusted. Furthermore, the illuminator IL may include various other components such as an integrator IN and a concentrator CO. An illuminator can be used to tune the radiated beam to give its cross section the desired uniformity and intensity distribution.
The radiation beam B is incident on a pattern forming apparatus (eg, mask MA) held on a support structure (eg, mask table MT) and is patterned by the pattern forming apparatus. After crossing the mask MA, the radiated beam B passes through a projection system PS that focuses this beam on the target portion C of the substrate W. With the assistance of a second positioning device PW and a position sensor IF (eg, an interfering element, a linear encoder, or a capacitive sensor), for example, to position a different target portion C in the path of the radiated beam B, a substrate table. The WT can be moved accurately. Similarly, using the first positioning device PM and another position sensor (not specified in FIG. 1), for example, after mechanically removing from the mask library or during scanning, the mask MA is emitted from the radiated beam B. It can be accurately positioned with respect to the path. In general, the movement of the mask table MT can be realized with the assistance of the long stroke module (coarse movement positioning) and the short stroke module (fine movement positioning) that form a part of the first positioning device PM. Similarly, the movement of the board table WT can be realized by using the long stroke module and the short stroke module which form a part of the second positioning device PW. In the case of a stepper (unlike a scanner), the mask table MT may only be connected to the short stroke drive or fixed. The mask MA and the substrate W can be aligned using the mask alignment markers M1 and M2 and the substrate alignment markers P1 and P2. Although the illustrated substrate alignment markers occupy a dedicated target portion, they can be placed in the free space between the target portions (these are known as line alignment markers). Similarly, in situations where multiple dies are provided on the mask MA, mask alignment markers may be placed between these dies.
The illustrated device can be used in the following preferred manner: That is, 1. In the step method, the mask table MT and the substrate table WT are basically kept stationary (that is, single) while the entire pattern applied to the radiated beam is projected onto the target portion C at one time. Static exposure). The substrate table WT is then moved in the X and / or Y directions so that different target portions C can be exposed. In the step method, the maximum size of the exposed area limits the size of the target portion C imaged with a single static exposure. 2. In the scanning method, the mask table MT and the substrate table WT are scanned synchronously (that is, single dynamic exposure) while the pattern applied to the radiated beam is projected onto the target portion C. The velocity and direction of the substrate table WT with respect to the mask table MT can be determined by the (reduction /) magnification and image inversion features of the projection system PS. In the scanning method, the maximum size of the exposed area limits the width of the target area (in the non-scanning direction) in a single dynamic exposure, while the moving length of the scan determines the height of the target area (in the scanning direction). decide. 3. Another method is to hold the mask table MT essentially stationary while holding the programmable pattern forming apparatus while projecting the pattern applied to the radiated beam onto the target portion C, and the substrate table WT. Move or scan. In this scheme, a pulse source is commonly used and the programmable patterning means is updated as needed with each movement of the substrate table WT or between continuous emission pulses during scanning. Such an operating scheme is readily applicable to maskless lithography utilizing programmable patterning means such as the types of programmable mirror arrays mentioned above.
It is also possible to use combinations and / or variants related to the usage methods described above, or completely different usage methods.
According to one aspect of the invention, the overlay error and other problems associated with the presence of the immersion and sealing member 12 are liquid evaporation that targets and controls the evaporation rate of the immersion in the substrate region. Handled by the controller. Liquid molecules absorb energy from their surroundings to evaporate, and the resulting cooling, especially when pumped, can result in significant and non-uniform changes in the temperature of key components such as substrate W. .. The heat-induced deformation can cause errors in the final image captured on the substrate. For example, evaporation of the immersion liquid left on the substrate after passing through the sealing member 12 can cause a local temperature drop of up to 3K. As a result, overlay errors for single machines above 20 nm can typically occur.
FIG. 5 shows the arrangement of sealing members 12 according to one or more embodiments of the present invention. The immersion liquid is confined inside the immersion liquid reservoir 25 arranged between the final element of the projection system PL and the substrate W. The immersion liquid is confined inside the immersion liquid reservoir 25 by the main body of the sealing member 12 and a gas seal 27 located on the lower periphery thereof and limiting the amount of immersion liquid that escapes from the immersion liquid reservoir 25 through the gap 22. Be done. The gas seal 27 is connected to a compressed gas supply system 30 that supplies compressed gas to the gas seal 27 via a compressed gas outlet 18 and a compressed gas supply pipe 15. The gas is drawn through the vacuum discharge port 17 and the vacuum discharge pipe 14. The immersion liquid that evaporates in the region of the gas seal 27 can be pumped through the vacuum discharge port 17. Alternatively, the liquid that escapes beyond the gas seal 27 into the lower region of the sealing member 12 in the gap 22 or escapes beyond the outer edge of the sealing member 12 is the environment outside the substrate W outside the sealing member 12. Can evaporate into.
If the substance is present in both liquid and gas forms, there will be a dynamic equilibrium in which the evaporation rate of the liquid will be balanced against the condensation rate of the vapor. Therefore, the amount of cooling generated by evaporation will be offset by the heat generated by condensation (in which case the high energy gas molecules bring energy to the environment as part of the transition to a lower energy liquid state. discharge). Therefore, the cooling power depends on the net evaporation rate (ie, the difference between the number of molecules entering the liquid state from the liquid state per unit time and the number of molecules entering the gas state to the liquid state per unit time). Both condensation and evaporation are statistical effects, and increasing the number of molecules involved increases the proportion of either process. Therefore, increasing vapor condensation increases the condensation rate, resulting in a decrease in the net evaporation rate. When steam consists of water molecules, such condensation is directly related to relative humidity, which defines the amount of water vapor present as a percentage of the maximum amount that can be present at a given temperature.
Utilizing this knowledge, according to one embodiment of the present invention, the cooling caused by the evaporation of the immersion liquid is controlled. As illustrated in FIG. 5, a compressed gas humidity control device 50 configured to interact with the compressed gas supply system 30 is provided, and the compressed gas is supplied to the gas seal 27 to have a relative humidity of 10% or more. Is also controlled to be high. Increasing the relative humidity of the gas increases the condensation rate, thus reducing the net evaporation rate and reducing cooling due to evaporation. The relative humidity is preferably set within a predetermined range determined with reference to the calibration measurement value. For the purpose of controlling cooling, the higher the relative humidity, the better. However, at very high relative humidity, the sealing member 12 can leave an excess amount of water in its wake. Moreover, if the mechanism provided near the outer diameter of the sealing member is insufficient for extracting the moist gas, the moist gas may remain and interfere with the operation of the position sensor IF. Therefore, the upper limit will generally depend on the structure and / or the details of the configuration of the sealing member. In addition or otherwise, this predetermined range can exceed 40%. Such high relative humidity can be achieved by using lower operating pressures than if otherwise selected solely for the purpose of achieving optimum sealing properties (typically 6 bar is available). is there. Ideally, an operating pressure should be selected that is as close to atmospheric pressure as possible, but on the other hand still provides a flow rate sufficient for the gas bearing 27 to perform its function. The lower the operating pressure, the less the decrease in relative humidity during expansion as the compressed gas exits the compressed gas supply system 30.
The compressed gas humidity control device 50 is arranged so as to respond to a temperature change of the substrate W and / or the substrate table WT. Such temperature changes can be measured, for example, by one or more temperature sensors 60 placed in the substrate table WT. According to an embodiment of the present invention, the compressed gas humidity control device 50 measures the temperature of the substrate W and / or the substrate table WT / substrate cage measured by one or more temperature sensors 60 at one or more locations. Arranged to compare with one or more temperatures Tt. That is, when a single temperature sensor 60 is present, the compressed gas humidity controller 50 compares this one measured temperature value with a single target temperature Tt. When a plurality of temperature sensors 60 are present, the compressed gas humidity controller 50 compares the plurality of measured values with a single target temperature Tt, or, for example, a specific region of the substrate W and / or the substrate table /. Compare with multiple target temperature Tts corresponding to the corresponding area of the substrate cage and thus corresponding to a particular group of temperature sensor measurements (average measurements within these are available). The compressed gas humidity controller 50 then adjusts the relative humidity of the compressed gas to reduce the difference between the measured value and one or more target temperatures, and the efficiency of such a process is PID (proportional, integrated). Controlled by a feedback controller such as a (differential) system.
Humidity control of the gas supplied to the gas seal 27 is most efficient for cooling caused by evaporation within the region of the gas seal 27, especially around the vacuum outlet 18 and the vacuum discharge pipe 14. It is preferable to have an additional mechanism to control the net evaporation of the liquid beyond the gas seal 27 and reaching the outside of the sealing member 12. Such an arrangement is illustrated in FIG. 6 according to an embodiment of the present invention. In this figure, a gas shower outlet 70 capable of supplying a gas stream having a relative humidity controlled to exceed 10% is provided. A gas shower humidity controller 75 is provided, which is a calibration measurement of temperature at one or more locations on the substrate W and / or the substrate table / cage supplied by one or more temperature sensors 60. Relative humidity can be adjusted according to values, calculated values, or measurements and by comparison with one or more target temperatures Tt. The preferred range of relative humidity in this case is 40% to 50%. When the gas shower humidity controller 75 is arranged to respond to temperature measurements, it is a gas to reduce one or more differences between the measured temperature and one or more target temperatures Tt. Relative humidity can be adjusted. That is, when a single temperature sensor 60 is present, the gas shower humidity controller 75 compares this one measured temperature value with a single target temperature Tt. When a plurality of temperature sensors 60 are present, the gas shower humidity controller 75 compares the plurality of measured values with a single target temperature Tt, or, for example, a specific region of the substrate W and / or the substrate table / substrate. Compare with multiple target temperature Tts corresponding to the corresponding area of the cage and thus corresponding to a particular group of temperature sensor measurements (average measurements within these are available). A feedback controller, such as a PID system, can control the efficiency of such a process.
The gas shower humidity controller 75 can be arranged to interact with the compressed gas humidity controller 50 to ensure that the relative humidity of the gas supplied by the gas seal 27 and the gas shower outlet 70 matches. These features make it possible to control changes in relative humidity outside the gas seal 27, which would otherwise occur for systems such as interferometers used to measure the position of the board table WT. Probably, it has a mechanism to avoid disturbance.
The substrate table WT is typically subjected to the substrate table displacement system 100 (see FIG. 8) with respect to the projection system PL and the encapsulating member 12 so that the patterned radiation beam can expose a continuous target portion of the substrate W. It is arranged in a movable manner. This process can help a small amount of immersion liquid to leak out of the immersion reservoir 25 region, despite the operation of the gas seal 27. In the above, the examples arranged so as to reduce the cooling of the components generated by reducing the evaporation of the immersion liquid have been discussed. According to another aspect of the present invention, by providing the substrate heater, the error caused by the cooling effect of the evaporating immersion liquid is dealt with, but this heater measures the position and speed of the substrate table WT with respect to the sealing member 12. , Acceleration, and at least one of the predetermined paths, and according to the local temperature of the substrate W and / or the substrate table WT, is configured to heat at least a portion of the substrate W. This substrate heater can be heated by several mechanisms. These mechanisms include one or more elements such as an infrared source, an incandescent electric resistance heater, and a hot air jet: An important factor in deciding which type of heater to use is not only how finely and quickly the heating power needs to be adjusted, but also how effectively the heater needs to be made small. It also includes whether or not there is. The latter factor is whether the heater needs to be embedded in or near the material intended for temperature control (eg, incandescent rays embedded in the substrate table WT), or the heaters operate at some distance. The importance varies depending on the type (radiation emission source or temperature-controlled gas injection source). In the case of a radiation source, the wavelength distribution of the radiation should be chosen so that it does not react with the resist constituents on the substrate W (infrared radiation would be safe for most resists in this regard). The choice of radiant intensity depends on the optical properties of the resist (such as its reflectance). This can be determined by the calibration measurements during the series of setups of the lithography equipment. If process step dependence is possible (eg, anti) It is also possible to perform calibration separately for each lot of substrates in a series of production situations (due to variations in firing rate) as a measurement step. As described below, in some embodiments of the invention, at least a portion of the existing substrate heaters are driven during a series of substrate exposures, i.e., when the sealing member 12 passes over the substrate W. It works on the principle of being done. However, a system that heats the substrate W before exposure to compensate for the expected cooling before it occurs is also within the scope of the present invention.
7 and 8 show an arrangement according to an embodiment of the present invention, which is embedded in the substrate table as the "local heater" 85 or in the sealing member 12 as the "remote heater" 86. Or it is equipped with a heater 85/86 system embedded in both. The local heater 85 is arranged to heat each of the predominantly specific regions of the substrate W and can be used together to control the temperature profile of at least a portion of the substrate W. The remote heater 86 heats different parts of the substrate W according to the position of the sealing member 12 with respect to the substrate W.
According to the first method of operation involving the local heater 85, the heating force and the relative timing of each heater set the starting temperature profile for the substrate W for a known period of time prior to the start of the substrate exposure cycle. It can be adjusted as such. Based on the calibration measurements and / or analysis of the test pattern created by the lithographic device, a starting temperature profile can be selected that substantially compensates for the cooling caused by the evaporation of the immersion liquid during the exposure cycle.
According to a second method of operation involving the local heater 85, each of these heaters 85 heats only when the sealing member 12 passes above the area in which they are positioned to heat. It can be arranged so as to switch to the radial state. For example, as shown in FIG. 7, the sealing member 12 (and thus the target area) moves with respect to the substrate W along the path 150 between the first die (or target area) 160 and the final die 170. In some cases, the local heater 85 will also switch on in a gradual manner along substantially the same path 150. This is achieved by programming the substrate temperature controller 110 for each local heater 85 to supply a series of time-delayed drive signals that are slightly delayed to the intended path of the sealing member 12 with respect to the substrate table WT. It is possible. Such desired routes can be stored in the substrate table routing device 90. Alternatively or additionally, the drive sequence of the local heater 85 can be derived from other functions of the substrate table routing device 90. For example, the board table routing device 90 may include means for measuring the position, velocity and / or acceleration of the board table WT (eg, based on an interferometer) and supplying this information to the board temperature control device 110. It is possible and this means can be configured to thus calculate the time point at which each local heater 85 should be driven. For example, the routing device 90 can be configured to transmit a drive signal to a given particular heater when it detects that it is moving away from or has passed through the sealing member 12. The output supplied by each local heater 85 can be set to be constant or change over time and to be the same as or different from the other local heaters 85. The optimum setting to use for each heater is the setting that best compensates for the power lost due to evaporation in that area. When the loss rate of the liquid from the sealing member 12 is constant, the output to be supplied by each heater 85 is substantially the same (that is, once the sealing member 12 passes through). (Because it can be known that the amount of liquid remaining on the substrate W and evaporating is almost constant). Alternatively, it can be known that more heating force is required within some regions, such as when the sealing member 12 changes direction with respect to the substrate table WT. Calibration measurements can be performed to determine the most efficient way to operate the heater output as a function of a particular substrate table path and required speed.
It is preferable that the remote heater 86 in the sealing member 12 can be positioned around the peripheral edge of the sealing member 12 as shown in FIG. Such an arrangement allows the heater to operate in close contact with the region where the evaporation process may be extracting most of the heat. Placement near the outer diameter can be selected as a compromise to avoid the area immediately surrounding the gas seal 27, which is in fact already tightly occupied by holes, pipes, and conduits. Since these heaters operate at a distance from the substrate W, a radiant or hot air jet heater mechanism is suitable. Creating a thermal surface in the base of the sealing member 12 is one way to enable the realization of a radiation source. Thermal insulation of such a device from other parts of the sealing member 12 improves the performance of these features. Alternatively or additionally, infrared bulbs may be used.
The output of the remote heater 86 can be controlled according to the moving direction of the substrate table, as set by the local heater 85 described above. For example, it can be configured to supply more heat from one side of the sealing member 12 than from the other side. As one aspect of the evaporation of the liquid where cooling escapes from the sealing member 12, the remote heater 86 on the trailing edge of the sealing member 12 (where the immersion liquid is likely to escape) is in front of the sealing member 12. It can be configured to emit more heating power than that placed on the edge (the substrate W is still dry). The effect of the remote heater 86 can be changed as needed by changing the output and / or width of the heater 86 around the periphery of the sealing member 12. Such latter parameters can be changed, for example, by progressively driving different parts of the split heater 86 or one heater 86 of the plurality of heaters 86.
The heaters 85/86 are shown embedded in the substrate table WT or sealing member 12, but it is understood that they can be positioned anywhere that can affect the temperature of the substrate W. Should be. For example, the radiant emission type heater can be positioned in a separate body different from the substrate table WT and the sealing member 12. If the substrate W is heated prior to exposure, it can be heated in a region separated from the region used for exposure to make it easier to incorporate the remote heater 86.
The lithography apparatus can also include a local temperature sensor 60, which is embedded in the substrate table WT in the embodiment shown in FIG. According to an embodiment of the present invention, these temperature sensors 60 measure the temperature of each substrate W region and / or the corresponding region of the substrate table / substrate cage affected by each local heater 85. Have been placed. This information is supplied to the substrate temperature controller 110, which in turn reduces the difference between one or more target temperatures Tt and the temperature measured by the local temperature sensor 60 with the local heater 85 and / Or the output control method of the remote heater 86 can be calculated. In this embodiment, it is preferred that the heaters 85 and / or 86 can be configured to have a variable output rather than a fixed output. In either case, a feedback controller (such as PID) can be used to optimize the efficiency of the convergence process.
By adjusting the temperature of the liquid supplied by the liquid supply system 130, the temperature of the substrate W and / or the substrate table / substrate cage can also be controlled. For example, the immersion liquid can be heated to a controlled temperature higher than 259 K. FIG. 5 shows an embodiment of the present invention comprising an immersion temperature control device 120 arranged to perform this function in cooperation with the liquid supply system 130. Immersion temperature control can be performed on the basis of calibration measurements or measurements from one or more temperature sensors 60 to select an immersion temperature that will effectively compensate for heat loss due to evaporation. Is. In the latter case, the output of the immersion temperature controller 120 produces one or more differences between one or more target temperatures Tt and one or more temperatures supplied by one or more temperature sensors 60. It can be controlled to be minimized, and the convergence process is controlled by a feedback controller such as a PID controller. That is, when a single temperature sensor 60 is present, the immersion temperature control device 120 compares this one measured temperature value with the single target temperature Tt. When a plurality of temperature sensors 60 are present, the immersion temperature controller 120 compares the plurality of measured values with a single target temperature Tt, or, for example, a specific region of the substrate W and / or the substrate table / substrate. Compare with multiple target temperature Tts corresponding to the corresponding area of the cage and therefore corresponding to a particular group of temperature sensor measurements (average measurements among these are available).
By adjusting the temperature of the gas supplied by the compressed gas supply system 30, the temperature of the substrate W and / or the substrate table / substrate cage can also be controlled. For example, compressed gas can be heated to controlled temperatures above 300 K. In this case, the lower limit of the temperature is higher than the temperature required for the immersion temperature control device 120 described above because the heat capacity of the gas is smaller than that of the liquid. According to one embodiment of the present invention, the compressed gas is supplied at a temperature in the range of 300K to 320K. FIG. 5 shows an embodiment of the present invention comprising a compressed gas temperature control device 140 arranged to perform a temperature control function in cooperation with the compressed gas supply system 30. Temperature control of the compressed gas can be performed on the basis of calibration measurements or measurements from one or more temperature sensors 60. In the latter case, the output of the compressed gas temperature controller 140 should minimize one or more differences between one or more target temperatures Tt and one or more temperatures fed by the temperature sensor 60. The convergence process is controlled by a feedback controller such as a PID controller. That is, when a single temperature sensor 60 is present, the compressed gas temperature controller 140 compares this one measured temperature value with a single target temperature Tt. When a plurality of temperature sensors 60 are present, the compressed gas temperature controller 140 compares the plurality of measured values with a single target temperature Tt, or, for example, a specific region of the substrate W and / or the substrate table / substrate. Compare with multiple target temperature Tts corresponding to the corresponding area of the cage and therefore corresponding to a particular group of temperature sensor measurements (average measurements among these are available).
As already discussed, the substrate heating requirements have a position dependence that is at least partially determinable by the path of the sealing member 12 above the substrate W. At least two processes have been identified as contributing to the cooling process. That is, the vaporization process of the liquid in the gap 22 between the substrate W and the sealing member 12, and when the exposed area is left in a damp state, the residual liquid left on the substrate W after the exposure evaporates. It's a process. The cooling force of the sealing member 12 (that is, cooling by the first process) depends on the speed of the sealing member 12 with respect to the substrate W, but is constant over time. The cooling power of the second process depends, among other things, on the amount of liquid left behind on the substrate W. The amount of cooling that needs to be compensated is generally a complex function of both processes, resulting in a complex position-dependent cooling force. The heat conduction inside the substrate W is also an important factor, and the unexposed region of the substrate W starts to be cooled by cooling the exposed portion of the substrate W even before the sealing member 12 reaches the unexposed region. means. However, if one process is considered at a time, several estimates are possible. For example, the evaporation of the residual immersion liquid on the substrate W and the exposure of the substrate configured to take about 30 seconds including the time between the final exposure and the removal of the substrate for about 5 seconds, and FIG. Considering only the direct cooling with 150 and the exposure sequence as referenced, the heat is about 20% to 30% due to the mechanism at the first exposure point 160 rather than at the final exposure point 170. It is predictable that many will be extracted. In some of the above embodiments with substrate heater 85/86, such an effect was considered by delaying the operation of the individual heaters along the path of the sealing member 12. A similar effect is to provide a higher heating force to the target area on the substrate W where the projection system is configured to project the patterned radiant beam first, and to produce the patterned radiated beam. It can also be realized by configuring a substrate heater that supplies a gradually decreasing heating force to the target region of the substrate W that is configured so that the projection system PL projects later. Noh. Such an arrangement can be modified to provide a more complex position dependency, depending on the particular setting of cooling characteristics to be compensated for.
Although it is technically possible to position a large number of local heaters 85 at many different locations on the substrate W, in practice a more limited number of heaters are provided to substantially route the encapsulating member 12. Positioning them in a targeted manner is almost equally effective and much more economical. This type of arrangement is shown in Figure 7. In this figure, an elongated substrate heater 85, such as an incandescent wire, connects one individually controllable element to the main scanning axis or process axis 181-187 of the sealing member 12 above the substrate W (each corresponding to a row of dies). It is arranged so that it is aligned with one of the. In the illustrated embodiment, each incandescent wire 85 is arranged to emit a constant heating force per unit length, and the incandescent wire aligned with the main scanning axis or the process axis 187 exerts the greatest heating force. One after another, the final incandescent wire corresponding to the main scan axis or process axis 181 (the smallest heating force is assigned) is reached so that the incandescent wire aligned with 186 has the next largest heating force. It is configured so that the heating power gradually decreases until the temperature is increased.
If a large number of local heaters are provided at different locations (eg, between 100 and 700 per substrate), it is preferable to position them as close as possible to the surface of the substrate W. However, in the arrangement with fewer heaters shown in FIGS. 7 and 8, it is preferred that the heaters be positioned substantially further apart so that each heater effectively controls the substrate W over a larger portion.
FIG. 9 shows an arrangement in which a continuous incandescent wire heater 85 is provided to heat the substrate W. In the illustrated embodiment, the incandescent ray heater 85 is substantially parallel (ie, orthogonal to the scanning direction) with respect to the main scanning axes 181 to 187 (shown in FIG. 7) of the sealing member 12. By having a long section 195, it is arranged to follow the path of the sealing member 12 to some extent. However, the pitches 191 to 193 between these longer sections are arranged so that, as shown, the board W gradually narrows toward the lower end of the board W, which corresponds to the area where the board W is first exposed. (Ie, pitch 191> pitch 192> pitch 193). This is because the incandescent wire heater 85 has the simplest and most robust construction (if the heating power is constant per unit length, it can actually correspond to an elongated resistance element of a constant cross section), and still This means that a gradually increasing heating force can be supplied toward the region where the substrate W is to be first exposed, which is the region of the substrate W that needs the greatest compensation for the cooling effect. Alternatively and / or as an additional arrangement, the incandescent wire heater 85 is directed towards the bottom edge of the substrate W in the orientation shown, eg, to provide heating power per unit length that varies along its length. Can be placed (to increase). When the incandescent wire operates by the electrical dissipation associated with the current flowing along its length, the variable heating force is a change in cross-sectional area (eg, the incandescent wire that becomes thinner where more output is needed). It can be realized by (providing) or changing the material used. In the latter arrangement, care must be taken to avoid high resistance points where joints are made between materials of different compositions.
10 and 11 show an arrangement in which the substrate heater comprises a system of heaters 85 that can be individually controlled. In the embodiment shown in FIG. 10, the individually controllable heater 85 is arranged as an elongated member substantially parallel to the main scanning axes 181 to 187 (that is, orthogonal to the scanning direction) and of the substrate W. Limited to heating within geometric limits. However, alternative arrangements of heaters are also compatible with the present embodiment of the present invention as long as they can be individually controlled. The heater array controller 180 controls each of the heaters 85, which can be individually controlled via the address bus. The heater array controller 180 itself describes a predetermined algorithm 190 that describes how each heater should be controlled individually as a function of time (and thus a function of the position of the sealing member 12 with respect to the individual heater in question). Receive input from. Suitable algorithms to use can be derived from calibration measurements and / or calculated values (eg, based on the amount of time, the predicted amount of liquid is expected to remain on the substrate W). This measure has the advantage of not requiring a temperature sensor, which greatly simplifies the structure.
Evaporation of the immersion liquid can also lead to cooling of the sealing member 12 itself. Such effects then lead to cooling of the substrate W by, for example, cooling, convection, and / or heat dissipation of the immersion and / or compressed gas. According to one aspect of the present invention, a sealing member temperature stabilizer is provided to reduce the cooling of the substrate W by such a mechanism.
Particularly relevant regions are around the vacuum discharge port 17 and in the vacuum discharge pipe 14. When the immersion liquid is present in these areas, the net evaporation is particularly pronounced (the evaporated gas is immediately pumped) as the vapor condensation is maintained at a low level by the vacuum system. One method that can control the overall cooling of the sealing member 12 by such a mechanism is illustrated in FIG. 12, in which the sealing member temperature stabilizer is arranged around the vacuum discharge pipe 14. It is carried out by a heat insulating sleeve 210. The thermal insulation sleeve 210 should preferably be formed from a material that has very low thermal conductivity at the predicted operating temperature of the lithography equipment. General-purpose plastics, PTFE (polytetrafluoroethylene), etc. may be suitable materials for the heat insulating sleeve 210. Alternatively or additionally, all or part of the sealing member itself may be made from a heat insulating material. Such measures may be constrained in the selection of materials with suitable mechanical characteristics, but are more effective and easier to implement than having only the heat insulating sleeve 210.
An additional and / or alternative measure is to provide a dedicated sealing member heater 220 that is arranged to provide compensatory heating power to the region of the sealing member 12 that is cooled by the evaporation of the immersion liquid. .. On the one hand, the sealing member 12 itself is heated and thus indirectly heating the substrate W, but the sealing member heater 220 can be arranged so as to directly heat the substrate W. This can be achieved by using a radiant emission heater such as the infrared heater described above in connection with the feasible substrate heater 85/86. In the arrangement shown in FIG. 12, the sealing member heater 220 is arranged around the vacuum discharge port and is located in a plane orthogonal to the axis of the sealing member 12 (into the page in the illustrated orientation). You can follow the shape of.
The heating power of the sealing member heater 220 is controlled by the sealing member temperature stabilizer according to inputs from one or more sources of several feasible sources. For example, the output of the sealing member heater can be adjusted in response to the flow rate in the vacuum discharge tube 14 that can be supplied by the compressed gas supply system 30. In this case, it is expected that a larger flow rate will require a larger heating force.
The sealing member heater 220 can also be controlled with reference to the temperature of the substrate W and / or the substrate table / substrate cage, which can be measured at one or more locations by one or more temperature sensors 60. As in the previous embodiment, the feedback controller can be used to reduce the difference between one or more substrate temperatures and one or more predetermined target temperatures Tt.
The sealing member heater 220 can also be controlled in response to the relative humidity of the gas supplied by the compressed gas outlet 18. This information can be supplied by a humidity sensor that can be placed in the encapsulation member or placed as part of the compressed gas supply system 30 (the latter case is illustrated in FIG. 13).
Finally, the encapsulant temperature stabilizer 200 can control the output of the encapsulant heater 220 relative to the required correction calibration table 230, which is one or more of the following elements: It is composed of measured values of substrate temperature, compressed gas flow rate, compressed gas flow temperature, vacuum discharge flow rate, vacuum discharge temperature, relative humidity of compressed gas, and sealing member temperature as a function of immersion temperature. Calibration measurements must be performed, but this strategy significantly reduces the need to incorporate additional functional components into the final lithographic equipment to be shipped to the customer.
When considering the substrate cooling issues associated with the cooled sealing member 12, the most important region of the sealing member 12 is the region closest to and / or facing the substrate W. According to an embodiment of the present invention shown in FIG. 14, the sealing member 12 is configured to arrange a network structure of a flow path in a layer 400 in a portion of the sealing member 12 closest to the substrate W. ing. The sealing member temperature stabilizer 200 is configured to control the heat exchange fluid supply system 410 that supplies the heat exchange fluid to the network structure at a controlled temperature and / or a controlled flow rate. A feedback control device can be provided to help control the substrate temperature in an efficient manner, as in the previous embodiment. In this case, the temperature and / or flow rate of the heat exchange fluid supplied by the fluid supply system 400 is one with one or more substrate temperatures and / or substrate table temperatures measured by the system of the local temperature sensor 60. It can be adjusted to reduce one or more differences from the above target temperature Tt. That is, when a single temperature sensor 60 is present, the fluid supply system 400 compares this one measured temperature with a single target temperature Tt. When a plurality of temperature sensors 60 are present, the fluid supply system 400 compares the plurality of measured values with a single target temperature Tt or, for example, a specific region of the substrate W and / or the substrate table / substrate. Compare with multiple target temperature Tts corresponding to the corresponding area of the cage and therefore corresponding to a particular group of temperature sensor measurements (average measurements among these are available). The temperature and / or flow rate of the fluid can also be controlled relative to the required correction calibration table 230, which is one or more of the following factors: substrate temperature, compressed gas flow rate, It is composed of measured values of the temperature of the compressed gas flow, the vacuum discharge flow rate, the vacuum discharge temperature, the relative humidity of the compressed gas, and the sealing member temperature as a function of the immersion temperature. Calibration measurements must be performed, but this strategy significantly reduces the need to incorporate additional functional components into the final lithographic equipment to be shipped to the customer.
Thus, the general advantage of the mechanism-dependent embodiments described above that are located within the sealing member 12 is that they can be implemented without affecting the dynamic performance of the substrate table WT. (This applies to both fluid-based systems and electrical systems). By adjusting the temperature of the sealing member, not only the short-term (for each die) temperature variation of the substrate W but also the long-term temperature variation for each substrate W is improved. More generally, the development costs (and development times) associated with improving the encapsulant are expected to be significantly reduced compared to when the substrate table WT is involved. In addition to the issues related to the dynamic control of the substrate table WT, another factor that prioritizes efforts on the encapsulating member 12 over the substrate table WT is the flatness requirement, which is relaxed about 100 times in the encapsulating member 12. .. This is important, for example, when the flow path is machined into the sealing member 12. Introducing holes near the surface (where it is most effective) reduces the stiffness of the thin thickness of the material left between the outer surface of the encapsulant and the inner flow path edge due to variations in heat exchange fluid pressure. Tends to introduce surface irregularities (bulges) that can result in (by doing).
15 to 18 are arrangements having a network structure of the fluid transport flow path in the same manner, but in these cases, they are arranged in close contact with the substrate W in the substrate table WT. Such a flow path arrangement is configured to control the substrate temperature, which may be adversely affected by the evaporation of the immersion liquid from the top surface of the substrate W.
In this embodiment, the substrate table heat exchange fluid control device 510 is provided to control the temperature and flow rate of the heat exchange fluid arranged so as to flow through the network structure of the flow path 500.
A feedback control device can be provided to help control the substrate temperature in an efficient manner, as in the previous embodiment. In this case, the temperature and / or flow rate of the substrate table heat exchange fluid is one or more substrate temperature and / or substrate table / substrate cage temperature measured by the system of local temperature sensor 60 and one or more. It can be adjusted to reduce the difference from the target temperature Tt.
Such an arrangement can work particularly effectively when a local substrate heater, such as an incandescent wire, is provided to implement the "push-pull" principle of temperature control. According to this embodiment, the substrate temperature control device 520 controls the operations of the substrate heater control device 430 and the substrate table heat exchange fluid control device 510. Minimize one or more differences between the board temperature measured at one or more points on the board W and / or board table / board cage by the local temperature sensor 60 and one or more target temperatures Tt. A feedback controller can be included as part of the substrate temperature controller 520 arranged so as to. That is, when a single temperature sensor 60 is present, the substrate temperature controller 520 compares this one measured temperature value with a single target temperature Tt. When a plurality of temperature sensors 60 are present, the substrate temperature controller 520 compares the plurality of measured values with a single target temperature Tt or, for example, a specific region of the substrate W and / or the substrate table /. Compare with multiple target temperature Tts corresponding to a particular group of temperature sensor measurements corresponding to the corresponding area of the substrate cage (average measurements among these are available). Alternatively, a feedforward loop can be used if the heat flow can be calculated as a function of the velocity and position of the sealing member 12 with respect to the substrate W. According to the "pull-push" principle, the heat exchange fluid controller 510 is arranged to supply the fluid at a temperature below the target temperature Tt and can effectively operate to cool the substrate W. The local substrate heater, which can be the electrical resistance heater (incandescent wire) described above, is capable of responding to a rapid increase in evaporation rate much more quickly than a heat exchange fluid controller. Their response speed is further improved by being set for the cooling operation of the heat exchange fluid controller. Furthermore, if the substrate temperature is exceeded, the cooling heat exchange fluid can be supplied to enable a quicker return to equilibrium than if no additional cooling mechanism were provided.
To facilitate machining (especially for a number of reasons), the reticulated structure of the flow path 500 is a nearly straight hole (drilled hole) placed in the plane of the board table, as shown in FIG. Includes an array of). The ends of such straight holes must be connected and water-sealed. This can be done by gluing a plug into the hole. However, a typical configuration with 4 mm holes at an 8 mm pitch may require more than 80 plugs. In addition to the problem of having to make a large number of individual elements, such an arrangement can result in dead ends where no fluid reaches or the fluid does not circulate. According to an embodiment of the present invention, such a problem is a clever method that does not cause a dead end and provides an annular groove 420 (shown in FIGS. 16-18) into which all through holes can be connected. It is overcome by providing it at the edge of the board table WT. Such an arrangement also has the other advantage that the fluid can circulate closer to the edges of the substrate table WT. The annular groove 420 can be sealed with a much smaller number of components. Although the illustrated embodiment uses a sealing ring 410, it is divided into two components for ease of assembly and can be adhered to the groove by gluing or some other standard technique. Improved fluid distribution provides more uniform and controlled cooling of the substrate table WT, allowing for more effective thermal management and thus improved overlay.
In the embodiment described above, the local substrate temperature sensor 60 (if provided) is shown embedded in the substrate table WT close to the substrate W. These sensors can operate on a variety of principles based on measurements of generally calibrated and reproducible temperature-dependent characteristics (such as electrical resistance). Although the local sensor is shown embedded in the substrate table, it can also be positioned in the sealing member 12 as shown in FIG. Since the thermal connection is relatively poor between both ends of the gap 22 (unlike between the substrate W and the sensor embedded in the substrate table WT, where high heat conduction is more easily placed), the sealing member 12 The sensor 60 disposed therein preferably operates by analyzing the radiation emitted from the substrate W. According to an embodiment of the present invention, a sensor of this type 60 is provided, which comprises a radiation capture and analyzer capable of measuring the intensity spectrum of the captured radiation over a wavelength range. Generally speaking, temperature is most accurately measurable when a wide wavelength range is selected. However, with respect to the temperature targeted in this application example, it is economical to select a limited wavelength range that includes and / or is centered on the infrared radiation band.
FIG. 20 shows an embodiment of the present invention, in which a local small temperature control system 600 is incorporated in the substrate table WT. In the illustrated embodiment, these control systems 600 are positioned near the tip of a raised portion (hump top 640) of the substrate table WT, which itself is in contact with the substrate W. Each small control system 600 includes a small temperature sensor 610 that can be implemented as a micro power consumption integrated circuit temperature sensor, and a small heater 620 that can be implemented as an integrated circuit heater (heat is dissipated by resistance). The small control system 600 is arranged to drive the heater component 620 to release heat when the substrate local temperature measured by the small temperature sensor 610 falls below a predetermined threshold. Once the temperature rises and exceeds the threshold again, the small controller 600 is configured to turn off the small heater. Such an arrangement has the advantage that the small dimensions of the control system 600 allow for significantly localized temperature control and that there is no need for a separate external control system to control the heater 620. ing. Only two wires (connection 630) are required to supply voltage to all of the small control system 600 in the board table WT. By forming the substrate table WT from a silicon wafer, a small temperature sensor 600 can be made in the hump top 640. Using micromanufacturing techniques such as MEMS (Micro Electro Mechanical Systems) and CMOS (Complementary Metal Oxide Semiconductor) technology, the standard substrate table WT structure is accurately replicated, while integrated on each hump top 640. Circuit temperature sensors / heaters 610/620 can be added, and means (connection 630) for electrically connecting them to the outside world can be provided.
FIG. 21 comprises a projection system controller 710 configured to adjust the characteristics of the patterned radiated beam in response to measurements of substrate and / or substrate table temperature measured by temperature sensor 60. An embodiment is shown. In the illustrated embodiment, a plurality of temperature sensors 60 are embedded in the substrate table WT. However, it is also within the scope of the present invention to provide temperature sensors elsewhere, such as in the sealing member 12, and / or to provide only a single temperature sensor.
As discussed above, evaporation of the immersion liquid on the substrate W leads to cooling of the substrate, and the resulting deformation may lead to overlay error, defocusing, aberrations and the like. According to the present invention, the projection system control device 710 adjusts the parameters of the patterned projection beam, that is, its overall magnification change, misalignment, etc., so as to compensate for the heat-induced deformation of the substrate W. Can be done. In one simple embodiment, when the projection controller 710 receives an input from the temperature sensor 60 indicating that the substrate W is uniformly below the target temperature in the first approximation, this device is created on the substrate W. It can be configured to scale the patterned projected beam by a fraction so as to reduce the size of the image. When the temperature of the substrate W and / or the substrate table WT is measured by multiple temperature sensors 60 so that a temperature profile can be obtained, in order to reduce errors such as overlay error, defocusing, and aberration. More complex corrections can be performed by the projection system controller 710. This measure is costly to mount and / or does not require a heating element to be incorporated into the encapsulating member 12 or the substrate table WT, which can interfere with the dynamic performance of the substrate table WT, and the temperature is abrupt. It provides a quick means of responding to changes. Such a form of compensation has the additional advantage of being independent of a particular cooling mechanism during operation and is applicable when at least one contribution to the temperature change of the substrate W is caused by a process other than evaporation of the immersion liquid. Is.
In the embodiment shown in FIG. 21, a heat-induced deformation computer is also provided to convert the measured value read by the temperature sensor 60 into the estimated deformation of the substrate W. This is achieved by first deriving the temperature profile of the substrate W and then calculating the thermal induction deformation using known thermal properties of the substrate W, such as the coefficient of thermal expansion of the substrate material. In the first approximation, the relative deformation of a portion of the substrate W is proportional to the temperature difference between the temperature of that portion and the reference operating temperature (corresponding to zero relative deformation). In the illustrated embodiment, the temperature sensor 60 needs to be embedded in the substrate table WT and additional calculations must be performed to derive the substrate temperature distribution from the measured values of the temperature sensor. In connection with this embodiment and other embodiments of the present invention, methods for making this feasible will be described below.
The measurement of the temperature of the substrate W is performed by the temperature sensor 60 positioned in the substrate table WT, according to some of the embodiments discussed above. Such an arrangement is structured because there is a relatively large space for positioning the sensors, they can be positioned robustly and accurately, and power can be more easily supplied by any electrical wiring required. Advantages. As discussed earlier, positioning the sensor in the board table WT at a distance from the board W provides an effective means of sampling a larger board W area per sensor 60. However, while the temperature of the material that directly surrounds the temperature sensor 60 can approximate the temperature of the substrate W, further analysis described below can reveal a more accurate state of the substrate temperature distribution. .. Such analysis can be performed as part of any of the above embodiments with the temperature sensor 60 positioned in the substrate table WT.
The heat transfer from the substrate surface to the height in the substrate table WT where the temperature sensor 60 is positioned can be expressed by the following equation. That is,
<maths num="1"><img file="JP4852278B2_D0001.tif" /></maths>With the above formula
<img file="JP4852278B2_D0002.tif" />Is the initial temperature of the substrate W
<img file="JP4852278B2_D0003.tif" />Is the current temperature of the board area measured by the sensor 60 embedded in the board table WT, and<img file="JP4852278B2_D0004.tif" />Is the temperature difference at the substrate level for the region. The temperature of the substrate region, and thus the temperature file of the substrate as a whole (if necessary), can be obtained based on this relational expression. For example, the following models are available. That is,
<maths num="2"><img file="JP4852278B2_D0005.tif" /></maths>The following equation can be obtained from the above equation. That is,
<maths num="3"><img file="JP4852278B2_D0006.tif" /></maths>The above equation is an equation for the temperature difference at the substrate height based only on the parameters τ and κ (which can be estimated from the test data).
Similar analysis can be used to derive more accurate measurements of substrate temperature from infrared temperature sensor signals. The problem here is that silicon (often used as a substrate material) is significantly infrared transmissive, so an infrared sensor positioned inside a sealing member 12 that "looks down" at substrate W is with substrate W. It is to receive a mixture of radiation emitted from both the board table WT directly below it.
As described above, when the sealing member 12 moves with respect to the substrate W, a thin film of liquid may remain on the upper surface of the substrate W in the wake of the sealing member 12. Without effective remedies, evaporation of this liquid can extract heat from the substrate W and / or the substrate table WT. The resulting temperature drop of the substrate W and / or the substrate table WT can lead to shrinkage, which in turn can lead to overlay error, general loss of performance / resolution and / or yield loss of the integrated circuit to be manufactured. Some solutions to this problem are described above, including providing a network of heating channels and / or an array of individually controlled electric heaters. However, it is difficult to coordinate the operations of such a heating mechanism in a method in which heat is generated only in a place where evaporation actually occurs. Therefore, it is difficult to reliably minimize the temperature gradient inside the substrate W.
According to an embodiment of the present invention, the lithography apparatus is provided with means for heating the immersion liquid left in the wake of the sealing member 12 by using microwave radiation. The frequency of microwave radiation primarily heats the immersion liquid directly, but can be adjusted so that it does not couple to surrounding equipment elements (eg, substrate table WT, substrate W, sealing member 12, etc.). Therefore, it is possible to accurately induce the heating force to the required location, thereby minimizing the temperature gradient. In principle, the heat required to evaporate the liquid can be completely supplied by the microwave source so that heat is not extracted from the substrate W.
FIG. 22 shows a microwave source 800 configured to provide suitable microwave radiation to heat the immersion liquid used and immersion within the area of interest (and immersion where heating is undesirable). An exemplary configuration with a microwave confinement cage 810 designed (to protect areas such as the reservoir 25) is shown. In the illustrated embodiment, the region includes a substantially annular substrate W region around the sealing member 12. The size of the area covered by the microwave confinement cage 810 is such that the liquid is far enough away from the microwave exposure area that the microwave radiation seals before the sealing member 12 finishes moving relative to the substrate table WT. It can be selected to be large enough to completely evaporate the liquid left behind in the wake of the stop member 12. Therefore, the size of the microwave confinement cage 810 depends on the intensity of microwave radiation to be maintained within the confinement cage 810, the speed at which the encapsulating member 12 passes over the substrate table WT, and within the wake of the encapsulating member 12. It is a function of the amount of liquid that is expected to remain in.
The microwave confinement cage 810 is made of metal material and has an opening of appropriate size to ensure substantially perfect reflection of microwaves. Propagation of microwave radiation inside the microwave confinement cage 810 is schematically shown by arrow 830. The output of the microwave source 800, which determines the rate at which the liquid left behind on the substrate W is heated, can be selected based on the calibration measurements. For example, test measurements can be performed on several different microwave source outputs to determine which output leads to the minimum overlay error. Alternatively, the temperature sensor 60 can be provided and incorporated in the feedback loop via the data connection 850. Such an arrangement can be advantageous when the velocity of the sealing member 12 changes over time and / or when the amount of immersion liquid escaping from the sealing member 12 changes. The feedback mechanism is also useful when the microwave heating arrangement should be used in combination with other compensation methods whose efficiency can vary over time. As in the feedback arrangement discussed above, in this case the feedback loop may be accompanied by an output adjustment of the microwave source 800 in order for the temperature measured by the temperature sensor 60 to converge towards one or more target temperatures. .. The microwave source 800 is thought to emit radiation of microwave wavelengths. However, if the wavelength of radiation that most effectively binds to the immersion liquid used is outside the normal wavelength range normally associated with microwaves, then the source 800 is the appropriate wavelength of radiation ( For example, it should be understood that it is adaptable to emit (in the infrared or visible spectrum range).
FIG. 23 shows the arrangement of a substrate heater that can adjust the spatial change of heat output according to the spatial change of the substrate temperature without requiring the complicated arrangement of the temperature sensor and / or the external control system. This is achieved by forming conductive strips 900 near the surface of the substrate table WT in good thermal contact with the substrate W. For example, the conductive strip 900 can be formed by coating the upper surface of the substrate table WT with a conductive material. In the illustrated embodiment, an external current source 920 (not shown) is provided through which the constant current 910 flows through each of the conductive strips 900. According to the first variant, a single current source 920 is provided to carry the same current through each conductive strip 900. Alternatively, a plurality of current sources 920 configured to carry different currents through the conductive strip 900 can be provided. In each case, the amount of heat generated by the heat generated by the resistance depends only on the local resistance of the material forming the conductive strip 900. It is kept constant as it does. According to the present invention, such materials generate significantly more heat in the lower regions (having higher resistivity) than in the relatively warmer regions of each conductive strip 900. As such, it is chosen to have a negative temperature dependence (ie, such that an increase in temperature leads to a decrease in resistance), preferably a negative temperature dependence of intensity. In this way, more heating power is naturally induced in such areas that require the most heating, thus reducing the temperature gradient. In particular, for the current 910, the difference in heating power between the lower temperature region and the higher temperature region causes the evaporation of the liquid on the surface of the substrate W (as discussed above, the non-uniformity of the substrate temperature). It can be changed until it substantially compensates for the heat extracted by (which is expected to be the main contributor). It is predicted that the heat generated in any given part of one of the conductive pieces is proportional to the square of the current multiplied by the resistance of this part.
In the above embodiment, the temperature-dependent substrate was heated by directly using the conductive piece itself as a heater by utilizing the temperature-dependent resistivity of the conductive piece 900. According to another embodiment of the present invention, they can also be used as temperature sensors in a feasible combination with the function of the conductive strip 900 as a heating element. The arrangement according to such an embodiment is shown in FIG. Again, the current 910 is passed through the conductive strips 900 that are arranged to have a temperature-dependent resistivity. As before, the temperature-dependent resistivity is preferably strongly negative, but weaker temperature-dependent and / or positive temperature-dependent is acceptable. According to such an embodiment, separate substrate heaters 930 are provided, which are each fed by a local power supply / amplifier 950. The electric power supplied to each substrate heater 930 is controlled based on the measured value of the local resistivity in the portion of the conductive strip 900 closest to the substrate heater 930. This can be achieved by measuring the potential difference between the closest electrodes to the 940, as shown in FIG. As before, the local resistance of the conductive strip 900 is a function of local temperature.
Calibration measurements can be used to establish a relationship between substrate W resistivity and local temperature, and the power supply / amplifier 950 has a power supply / amplifier 950 between the measured resistivity and the resistivity corresponding to the desired temperature. It can be configured to adjust the output of the substrate heater 930 based on the difference between the two.
The above arrangement has the advantage that it is not constrained by the temperature-dependent strength of the resistivity of the conductive strip 900, and in principle can provide a stronger space-dependent heating force to the substrate W. High spatial resolution is possible with numerous pairs of power supply / amplifier 950 and board heater 930. Furthermore, since the heating force to be supplied to the substrate heater 930 is determined by a simple measurement of the resistivity in the vicinity of the conductive strip 900, it is complicated at the level of the substrate table and is complicated in a large electronic device or externally provided. No control electronics required. The amplification constant (or amplification function, i.e., a function that describes how much the local heater output should be changed when the temperature shifts from the desired temperature) provided by the power supply / amplifier 950 is pre-based on the calibration measurements. It is determinable and can be stored in hardware.
FIG. 25 shows an embodiment of the present invention in which the substrate W is heated by an induction heater. This measure has the advantage of heating mainly the parts that need to be heated (eg, in the vicinity of the sealing member 12). The induction source 960 operates to supply an induction heating force by coupling to an induction element 970 formed inside the substrate table WT, preferably at a position such that it is in proper thermal contact with the substrate W. Then, the output of the induction source 960 is controlled by the induction control device 980. The induction controller 980 can change the output of the induction source 960 according to a preset procedure (for example, such that the sealing member 12 mainly heats the substrate W region that has just passed above). Multiple spatially separated induction sources and / or elements can be provided. For example, each element can be configured to provide the same or different heating forces to heat the substrate W in such a way as to reduce the temperature gradient. Alternatively, the guidance controller 980 can use a feedback model. It can be configured to modify the output of one or more sources 960 so that the temperature measured by one or more temperature sensors 60 converges to one or more corresponding target temperatures. Using induction heating to heat the substrate table WT has the other advantage of requiring only minor changes to the substrate table WT (such as the addition of an induction element 970). Therefore, the mechanical operation of the board table WT is not so disturbed. The fact that the induction source 960 is mechanically separate from the induction element 970 is also advantageous from the viewpoint of expandability. That is, each component is highly freely adaptable to the other components.
As explained above, one measure to reduce the cooling caused by the evaporation of the immersion liquid from the surface of the substrate W is to supply a humidifier to the gas seal 27 (humidifier is the immersion). It is broadly interpreted to mean a gas that contains a significant portion of the liquid in the form of vapors). When the atmosphere above substrate W contains a high proportion of immersion vapor, the dynamic equilibrium established between the evaporation of immersion vapor from substrate W and the condensation of immersion vapor on substrate W is the substrate W. The net evaporation rate is designed to be lower than when the upper atmosphere is dry (ie, does not contain a significant amount of immersion vapor). In order for such a mechanism to work in a reproducible and consistent manner, it is necessary to provide reliable means for humidifying the gas supplied to the gas seal 27. According to an embodiment schematically illustrated in FIG. 26, a humidifying portion 1000 is provided for this purpose. Gas is input into the humidified section 1000 from a clean gas source (eg) through the conduit 1005 to the evaporation vessel 1010. The evaporation vessel 1010 comprises an internal heating element that heats one or more immersion tanks to generate immersion vapor. The immersion vapor thus generated is mixed with the clean gas supplied through the conduit 1005 and output from the evaporation vessel 1010 via the conduit 1015. The partially saturated gas is then input to the condensing vessel 1020 (also called the "cooling vessel"), where the mixture of gas and immersion vapor becomes supersaturated and the mixture is flooded. Is cooled to the extent that it condenses. What remains in the form of a gas is almost or just 100% saturated by the immersion vapor at the operating temperature of the condensing vessel 1020. A gas source thus 100% saturated is then entered into the mixing chamber 1040 via conduit 1025, where such a gas source is via conduit 1045 at a controlled temperature and / or controlled saturation level. The gas can be mixed with the dry gas source input at the controlled flow rate from the dry gas source 1030 via the conduit 1035 and then supplied to, for example, the gas seal 27.
An alternative system for humidifying a gas is to allow the gas to pass through a so-called bubbler, which is a perforation device immersed in a container containing liquids and liquid vapors. The gas is gradually saturated by the liquid as it passes through. With such an arrangement, it is difficult to control the level of saturation or humidity of the gas produced. All variations in flow rate, vessel temperature, or liquid level affect the amount of liquid vapor retained in the gas leaving the system. In particular, it is difficult to achieve 100% saturation using this method. Optimizing the performance of such systems may require the design of relatively complex devices, such as ensuring proper and reproducible contact between liquids and gases.
As described above, evaporation of the immersion liquid from the substrate W can adversely affect the performance of the lithography equipment. Foreign matter in the liquid can cause particle contamination (also known as aqueous contamination) on the substrate W. Evaporation can also adversely affect overlay performance, focusing and optical performance due to the cooling effect. Humidifiers in the gas seal 27 can be used to minimize evaporation. According to one strategy, a 100% saturated gas is desirable so that the net evaporation from the substrate W surface is zero. An embodiment designed to produce a 100% saturated gas in a controlled manner has been described above. However, when the gas is output from the gas seal 27, its expansion inevitably reduces the relative humidity of the gas. This means that, in practice, when the gas is delivered at the operating temperature of the substrate W (eg, 22 ° C), the maximum achievable humidity at the point of use (ie, the substrate surface) is substantially below 100%. For example, it can mean that it can be about 60%. If an atmosphere with a relative humidity below 100% is maintained above the substrate, some net evaporation will occur.
According to an embodiment schematically illustrated in FIG. 27, the gas humidity after the gas expands away from the gas seal 27 is controlled (reduced) by an increase in the temperature of the gas supplied to the gas seal.
In such a scenario, the hot gas leaving the gas seal 27 is rapidly exposed to an environment at a lower temperature (ie, the operating temperature of the lithographic apparatus) to cool. Cooling tends to reduce the level of saturation or relative humidity. The overall temperature drop can be controlled to tightly compensate for the expansion of the gas and the associated decrease in saturation.
In a system maintained at an operating temperature of 22 ° C, the gas is supplied to the gas seal 27 in a nearly saturated state (eg, 90% to 100% relative humidity), and the sealing member pressure typically drops by 0.4 bar. A temperature shift between 1K and 5K may be appropriate to maintain a relative humidity of about 100% in the gas left above the substrate W outside the gas seal 27. Careful system design is required to prevent the condensation of highly saturated gas before it leaves the gas seal 27. For example, the wall of the conduit that penetrates the sealing member 12 and reaches the gas seal 27 is thermally insulated to isolate the hot gas from the cold sealing member 12 and prevent condensation on the conduit wall. Should be.
FIG. 27 above shows, for example, an exemplary arrangement for controlling the temperature of the gas to be fed to the gas seal 27, which can be positioned, for example, between the humidified portion 1000 and the gas seal 27. .. A relatively cold saturated gas is supplied to the heat exchanger 1100 via the conduit 1045, which heats the saturated gas to the target temperature by exchanging heat with the heat exchange fluid supplied by the heater 1110. The heater 1110 supplies the heat exchange fluid at temperature T1 via the input pipe 1120 and receives the heat exchange fluid at temperature T2 via the input conduit 1130, where T1 is larger than T2. Heater 1110 heats the heat exchange fluid, for example, with a Peltier heater. According to the deployment as an example, a Peltier heater operating in the range of 500 watts to 1500 watts to produce temperature controlled water with an accuracy of ± 0.01 ° C for a set point of 27 ° C. Is provided.
According to one embodiment of the invention schematically illustrated in FIG. 28, a humidifying body is highly purified using a humidifying cabinet 1200 in which several evaporation units 1220 arranged in parallel operate to evaporate the liquid. The flow is generated. The temperature of the generated humidifier is controlled by supplying each of the evaporators 1220 with a temperature-controlled heat exchange fluid stream through conduit 1205. The heat exchange fluid can be supplied by the heat exchange fluid source 1110, which can also be used to control its temperature just before the saturated gas is delivered to the gas seal 27, as described above. Can be done. Alternatively, a separate heat exchange fluid source can be provided. The humidified and temperature controlled gas is fed through the hydrophobic filter 1210 to the output valve 1250 before being fed to the gas seal 27 via the heat exchanger 1100.
Even if the humidifier from the humidification cabinet 1200 changes or stops, it is stable for a long time until the equilibrium changes and the saturated gas can be supplied to the gas seal 27 again at a properly controlled temperature and saturation. Humidification time may be required. However, due to the dynamic nature of the roles played by the sealing member 12 and the gas seal 27, the gas flow rate required by the gas seal 27 can vary considerably over time, for example, for a short period of time when the gas seal 27 does not operate. Can exist. Rather than adapting a system that may require substantial and complex additional equipment to stabilize the system more quickly, the present invention allows the gas to be discharged to an external reservoir or outlet at a controlled flow rate. Includes discharge system 1240. The discharge system 1240 can be configured so that the flow rate from the humidification cabinet 1200 remains constant. This can actually be achieved by ensuring a constant total flow rate through the main valve 1250 and the discharge system 1240. This can be done by configuring the discharge system 1240 to have a flow impedance that corresponds to the measured value of the pressure gauge 1230 corresponding to the "feel" back pressure of the humidifier cabinet 1200. In particular, such pressure should be kept constant. This arrangement avoids the need for stabilization time between the different operating stages of the gas seal 27, which not only improves stability but also increases throughput.
All of the above features are possible in any combination and are applicable when relating to any type of liquid supply system, including the systems described in the Background Techniques section above.
Although the text specifically mentions the use of lithography equipment in the manufacture of ICs (Integrated Circuits), the lithography equipment described herein includes induction and detection for integrated optics, magnetic domain memory. It should be understood that there may be other applications such as the manufacture of patterns, liquid crystal displays (LCDs), thin film magnetic heads, etc. In the context of such alternative applications, any use of the terms "wafer" or "die" herein is synonymous with the more general terms "board" or "target portion", respectively. Those skilled in the art will understand that it can be considered to be. The substrates referred to herein are processed before or after exposure, for example, in a track (typically a means of coating a substrate with a layer of resist and developing an exposed resist) or measuring or inspecting means. It is possible. Where applicable, the disclosure of the present invention can be applied to such and other substrate processing means. Furthermore, as used herein, the term substrate may refer to a substrate that already contains layers that have been processed several times, for example, when the substrate is processed more than once to create a multilayer IC. There is also.
Although it has been mentioned above that the embodiments of the present invention are used in connection with optical lithography, the present invention can also be used for other application examples such as imprint lithography, and depending on the situation, optical It will be understood that it is not limited to lithography. In imprint lithography, the fine features of the pattern forming apparatus define the pattern created on the substrate. The fine features of the pattern forming apparatus can be embossed into a resist layer applied onto the substrate, on which the resist is cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. The pattern forming apparatus removes the resist from the resist when it cures, leaving a pattern in it.
As used herein, the terms "radiation" and "beam" refer to ultraviolet (UV) radiation (eg, having wavelengths at or near 365 nm, 248 nm, 193 nm, 157 nm, 126 nm) and extreme ultraviolet (EUV) radiation (eg, having wavelengths at or near 365 nm, 248 nm, 193 nm, 157 nm, 126 nm). Includes all types of electromagnetic radiation, including particle beams such as ion beams or electron beams as well as (having wavelengths in the range of 5 nm to 20 nm).
The term "lens" can, in some circumstances, refer to any one or a combination of various types of refractive, reflective, magnetic, electromagnetic, and electrostatic optical elements.
Although the specific embodiment of the present invention has been described above, it will be understood that the present invention can be implemented in other ways besides the description of the present invention. For example, the present invention presents a computer program comprising one or more sequences of machine-readable instructions describing the methods disclosed above, or a data storage medium (eg, a semiconductor memory) for storing such computer programs. , Magnetic or optical disc).
The present invention can be applied to any immersion lithography apparatus, particularly, but not limited to, the types described above.
The above description is exemplary and is not intended to be limiting. Therefore, it will be apparent to those skilled in the art that modifications can be made to the described invention without departing from the appended claims.
<figref num="1">It is a figure which shows the lithography apparatus by one Example of this invention.</figref><figref num="2">It is a figure which shows the liquid supply system used in the prior art lithography apparatus.</figref><figref num="3">It is a figure which shows the liquid supply system used in the prior art lithography apparatus.</figref><figref num="4a">It is a figure which shows the liquid supply system used in another prior art lithography apparatus.</figref><figref num="4b">It is a figure which shows the liquid supply system used in another prior art lithography apparatus.</figref><figref num="5">It is a figure which shows the sealing member by one Example of this invention, and shows the interaction with the compressed gas humidity control device, the immersion liquid temperature control device, and the compressed gas temperature control device.</figref><figref num="6">It is a figure which shows the sealing member, the gas shower outlet and the gas shower outlet control device by one Example of this invention.</figref><figref num="7">It is a top view which shows the substrate table which comprises the system of the local heater and the substrate temperature control device by one Example of this invention.</figref><figref num="8">FIG. 7 is a side view showing the substrate table of FIG. 7, and also shows a plurality of temperature sensors, a substrate table routing device, and a substrate heater arranged in a sealing member.</figref><figref num="9">It is a top view which shows the substrate table, and shows the arrangement of the substrate heater arranged so as to dissipate a larger output in the lower region than the upper region of a substrate.</figref><figref num="10">It is a figure which shows the array of the substrate heater which can be individually controlled by one Example of this invention.</figref><figref num="11">It is a side view which shows the arrangement of FIG. 10, and also shows the interaction with a heater array control device and a predetermined algorithm input device.</figref><figref num="12">It is a partial view which shows the sealing member by one Example of this invention, and shows the heat insulation sleeve for the vacuum discharge port, the vacuum discharge pipe, and the sealing member heater.</figref><figref num="13">It is a figure which shows the interaction between a sealing member and a sealing member temperature stabilizer by one Example of this invention.</figref><figref num="14">It is a figure which shows the sealing member provided with the network structure of the fluid transport flow path and the fluid supply system by one Example of this invention.</figref><figref num="15">It is a figure which shows the sealing member and the substrate table, and the substrate table is a network structure of a fluid transport flow path and an individually controllable heater controlled by a substrate temperature control device including a substrate table heat exchange fluid and a substrate heater control device. It has an array.</figref><figref num="16">It is a figure which shows the substrate table which has the network structure of the flow path and the annular groove by one Example of this invention.</figref><figref num="17">It is a figure which shows the substrate table which is sealed by the sealing ring by one Example of this invention, and includes the annular groove according to FIG.</figref><figref num="18">It is a figure which shows the substrate table which is sealed by the sealing ring by one Example of this invention, and includes the annular groove according to FIG.</figref><figref num="19">It is a figure which shows the lithography apparatus by one Example of this invention, and shows that the temperature sensor is positioned in the substrate table and the sealing member.</figref><figref num="20">It is an enlarged view which shows the substrate table in the substrate area, and shows the arrangement of the compact temperature control system by one Embodiment of this invention.</figref><figref num="21">It is a figure which shows the projection system control apparatus and the heat induction deformation computer according to one Example of this invention.</figref><figref num="22">It is a figure which shows the microwave source and the microwave confinement cage for heating the immersion liquid on the substrate surface.</figref><figref num="23">It is a figure which shows the arrangement of the resistance heating piece and the related current flow.</figref><figref num="24">It is a figure which shows the single resistance piece used as a local temperature sensor for a system of local heaters.</figref><figref num="25">It is a figure which shows the arrangement for induction heating of a substrate table WT.</figref><figref num="26">It is a figure which shows the apparatus for generating the flow of the gas which has a controlled humidity level.</figref><figref num="27">It is a figure which shows the heat exchange apparatus for controlling the temperature of a gas flow.</figref><figref num="28">It is a figure which shows the discharge system for enabling the stable operation of a humidifier cabinet.</figref>
35 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 Sheet 21 Sheet 22 Sheet 23 Sheet 24 Sheet 25 Sheet 26 Sheet 27 Sheet 28 Sheet 29 Sheet 30 Sheet 31 Sheet 32 Sheet 33 Sheet 34 Sheet 35
Every citation, both ways
| Document | Relation | Office | Cited during |
|---|---|---|---|
| KR20170008863A | Cited by | Republic of Korea | Examiner |
| WO2004086470A1 | Cites | World Intellectual Property Organization (WIPO) | – |
| WO2006003373A1 | Cites | World Intellectual Property Organization (WIPO) | – |
| JP2005236121A | Cites | Japan | – |
| JP2004086470A | Cites | Japan | – |
| JP2008504708A | Cites | Japan | – |
| WO2004053955A1 | Cites | World Intellectual Property Organization (WIPO) | – |
| JP10303114A | Cites | Japan | – |
| JP2004165666A | Cites | Japan | – |
| WO2004055803A1 | Cites | World Intellectual Property Organization (WIPO) | – |
| JP2006510146A | Cites | Japan | – |
35 members in 7 offices
Priority claims2
| Document | Office | Kind | Date |
|---|---|---|---|
| 10917535 | United States of America | – | |
| 91753504 | United States of America | A |
Members35
| Document | Office | Kind | |
|---|---|---|---|
| US2006033892A1 | United States of America | A1 | |
| US2006033898A1 | United States of America | A1 | |
| EP1628161A2 | European Patent Office (EPO) | A2 | |
| JP2006054468A | Japan | A | |
| CN1746775A | China | A | |
| SG120255A1 | Singapore | A1 | |
| KR20060050451A | Republic of Korea | A | |
| TW200617616A | Taiwan Province of China | A | |
| EP1628161A3 | European Patent Office (EPO) | A3 | |
| SG131107A1 | Singapore | A1 | |
| KR100760317B1 | Republic of Korea | B1 | |
| US7304715B2 | United States of America | B2 | |
| JP2009105443A | Japan | A | |
| TWI322929B | Taiwan Province of China | B | |
| CN1746775B | China | B | |
| US7804575B2 | United States of America | B2 | |
| CN101923290A | China | A | |
| US2010321650A1 | United States of America | A1 | |
| JP4852278B2This record | Japan | B2 | |
| JP2012064982A | Japan | A | |
| US2012113402A1 | United States of America | A1 | |
| CN101923290B | China | B | |
| EP1628161B1 | European Patent Office (EPO) | B1 | |
| JP5275067B2 | Japan | B2 | |
| JP2014027308A | Japan | A | |
| JP5699072B2 | Japan | B2 | |
| JP5699197B2 | Japan | B2 | |
| US9188880B2 | United States of America | B2 | |
| US2016048085A1 | United States of America | A1 | |
| US9268242B2 | United States of America | B2 | |
| US10254663B2 | United States of America | B2 | |
| US2019235397A1 | United States of America | A1 | |
| US10838310B2 | United States of America | B2 | |
| US2021063898A1 | United States of America | A1 | |
| US11378893B2 | United States of America | B2 |
28 legal events, as the office reported them to INPADOC
Over the term
Point at a mark for the eventEvents
| Event | Code | |
|---|---|---|
| Cancellation because of no payment of annual feesLAPS | LAPS | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Renewal fee payment (event date is renewal date of database)FPAY | FPAY | |
| Certificate of patent or registration of utility modelJAPANESE INTERMEDIATE CODE: R150R150 | R150 | |
| Certificate of patent or registration of utility modelJAPANESE INTERMEDIATE CODE: R150R150 | R150 | |
| First payment of annual fees (during grant procedure)JAPANESE INTERMEDIATE CODE: A61A61 | A61 | |
| Written decision to grant a patent or to grant a registration (utility model)JAPANESE INTERMEDIATE CODE: A01A01 | A01 | |
| Written decision to grant a patent or to grant a registration (utility model)JAPANESE INTERMEDIATE CODE: A01A01 | A01 | |
| Decision of grant or rejection writtenTRDD | TRDD | |
| Request for written amendment filedJAPANESE INTERMEDIATE CODE: A523A521 | A521 | |
| Written permission of extension of timeJAPANESE INTERMEDIATE CODE: A602A602 | A602 | |
| Written request for extension of timeJAPANESE INTERMEDIATE CODE: A601A601 | A601 | |
| Notification of reasons for refusalJAPANESE INTERMEDIATE CODE: A131A131 | A131 | |
| Request for written amendment filedJAPANESE INTERMEDIATE CODE: A523A521 | A521 | |
| Notification of reasons for refusalJAPANESE INTERMEDIATE CODE: A131A131 | A131 | |
| Request for written amendment filedJAPANESE INTERMEDIATE CODE: A523A521 | A521 | |
| Notification of reasons for refusalJAPANESE INTERMEDIATE CODE: A131A131 | A131 | |
| Notification of revocation of power of attorneyJAPANESE INTERMEDIATE CODE: A7425RD05 | RD05 | |
| Notification of appointment of power of attorneyJAPANESE INTERMEDIATE CODE: A7423RD03 | RD03 |
Numbers
- Publication
- 4852278
- Application
- 233909
Titles2
- Japanese
- リソグラフィ装置及びデバイス製造方法
- English
- Lithography equipment and device manufacturing method
Classification
- CPC, 5
- G03F7/70808
- H10P76/2041
- G03F7/70841
- G03F7/70875
- G03F7/70341
- IPC, 2
- H01L21 027
- G03F7 20
