Position sensing method, position sensor, exposure method, aligner, recording medium and manufacturing method of device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a position detection method, a position detection device, an exposure method, an exposure device, a recording medium, and a device manufacturing method, and more specifically, a position detection method and a position for detecting the position information of a mark formed on an object. A detection device, an exposure method using the position detection method, an exposure device including the position detection device, a recording medium in which program contents for executing the position detection method are stored, and a device manufacturing method using the exposure method. Regarding.

【0002】

[Conventional technology]

Conventionally, in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, etc., a resist or the like is applied to a pattern formed on a mask or a reticle (hereinafter, collectively referred to as a "reticle") via a projection optical system. An exposure apparatus that transfers onto a substrate such as a wafer or a glass plate (hereinafter, appropriately referred to as a "substrate or wafer") is used. As such an exposure apparatus, a static exposure type projection exposure apparatus such as a so-called stepper and a scanning exposure type projection exposure apparatus such as a so-called scanning stepper are mainly used.

【0003】

In such an exposure apparatus, it is necessary to perform high-precision alignment of the reticle and the wafer prior to exposure. In order to perform this alignment, a position detection mark (alignment mark) formed (exposure transfer) in the previous lithography process is attached to each shot region on the wafer, and the position of the alignment mark is detected. This makes it possible to detect the position of the wafer (or the circuit pattern on the wafer). Then, alignment is performed based on the detection result of the position of the wafer (or the circuit pattern on the wafer).

【0004】

Currently, several methods have been put into practical use for detecting the position of an alignment mark on a wafer. Recently, an optical image of an alignment mark is imaged by an imaging device, and the imaging signal, that is, the light intensity distribution of the image is captured. Position detection by image detection, in which the alignment mark position is detected by analysis, has become the mainstream. As a method of analyzing such a signal waveform, there is a pattern matching (template matching) method in which the position of the imaged alignment mark is used as a parameter and the correlation with the template waveform prepared in advance is examined within the imaging range of the alignment mark. By analyzing the signal waveform using this pattern matching method and obtaining the parameter value having the highest correlation with the template waveform, the position of the alignment mark was detected with high accuracy.

【0005】

[Problems to be Solved by the Invention]

The conventional method of template matching of the above-mentioned mark imaging signal (hereinafter, also referred to as raw waveform) is called noise having a period sufficiently smaller than the arrangement period of the line pattern (hereinafter, referred to as high frequency noise). ) Has high resistance. For example, in the case of a line-and-space mark in which a plurality of line patterns are arranged in a predetermined direction at a predetermined interval, the raw waveform template matching is performed even when high-frequency noise is superimposed on the imaging signal. Therefore, the mark position can be detected with high accuracy. This is because template matching generally has a kind of noise averaging effect, and in the case of high-frequency noise, the noise effect can be efficiently removed by the noise averaging effect.

【0006】

However, the noise superimposed on the image pickup signal is not always limited to high frequency noise. For example, in the case of the line-and-space mark, noise having a period equal to or longer than the arrangement period of the line pattern (hereinafter, referred to as low frequency noise) may be superimposed on the imaging signal. In such a case, the influence of noise due to the noise averaging effect due to the template matching of the raw waveform cannot be efficiently removed. Therefore, when low-frequency noise is superimposed on the imaging signal, it becomes impossible to accurately detect the mark position by template matching of the raw waveform.

【0007】

The present invention has been made under such circumstances, and the first object thereof is a position detection method and a position detection device capable of accurately detecting the position information of a mark formed on an object. Is to provide.

【0008】

A second object of the present invention is to provide an exposure method and an exposure apparatus capable of transferring a predetermined pattern to a substrate with high accuracy.

【0009】

A third object of the present invention is to provide a recording medium in which a program capable of accurately detecting the position information of a mark formed on an object by reading and executing it is stored. ..

【0010】

A fourth object of the present invention is to provide a device manufacturing method capable of producing a highly integrated device having a fine pattern.

【0011】

[Means for solving problems]

As a result of research on the position detection of the position detection mark composed of the alignment line pattern and the space pattern formed on the object, the present inventor has obtained the signal level of the imaging signal (that is, that is, in the position detection of the mark. It is important to detect the position of the boundary (hereinafter referred to as "edge") between the line part and the space part where the signal brightness changes rapidly, and the position where the absolute value of the rate of change is maximum in the signal waveform of the imaged signal. It was also found that the edge position can be detected by detecting the position of the curved point in the signal waveform of the imaging signal. Further, the width of the edge portion is very narrow compared to the width of the line portion and the width of the space portion, and the waveform of the edge portion is greatly affected when high frequency noise is superimposed. It was also found that when the superimposed noise is low frequency noise, it is hardly affected. The present invention has been made based on these findings.

【0012】

The first position detection method of the present invention is a position detection method for detecting the position information of a mark (MX, MY) formed on an object (W), and is a first step of imaging the mark; The second step of obtaining the differential waveform of the predetermined order of the signal waveform obtained in the first step; and the third step of detecting the position information of the mark based on the correlation between the differential waveform and the predetermined template waveform. It is a position detection method including.

【0013】

According to this, the mark imaging signal obtained in the first step is differentiated in the second step, and the signal level of the imaging signal changes abruptly, so that the waveform focuses on the edge that is not easily affected by low frequency noise. A differential waveform of a predetermined order of the imaging signal is obtained. Here, for example, if the differential waveform of the predetermined order is the differential waveform of the first order, the change depending on the position of the change rate of the signal level of the image pickup signal is obtained as a waveform, so that the edge portion where the signal level of the image pickup signal changes abruptly. A waveform showing the characteristics of is obtained. Further, for example, if the differential waveform of the predetermined order is the differential waveform of the second order, the change depending on the position of the rate of change of the signal level in the differential waveform of the first order can be obtained as a waveform, so that the waveform showing the characteristics of the edge portion is also obtained. can get. Further, even if the differential waveform of the predetermined order is used as the differential waveform of the third order or higher, a waveform showing the characteristics of the edge portion can be obtained. The position information of the mark is detected by template matching the differential waveform of the predetermined order in which the characteristics of the edge portion appear, which is obtained in this way, in the third step.

【0014】

Therefore, even when low-frequency noise is superimposed on the image pickup signal of the mark and the mark position information cannot be detected accurately by the raw waveform template matching, the mark position information can be detected accurately.

【0015】

In the first position detection method of the present invention, the third step changes the relative positional relationship between the differential waveform and the template waveform, and the correlation coefficient between the differential waveform and the template waveform at each relative position. The fourth step of determining the mark and the fifth step of detecting the position information of the mark based on the relative positional relationship in which the correlation coefficient is the largest can be included. In such a case, in the fourth step, the relative positional relationship between the differential waveform and the template waveform is used as a parameter, the correlation coefficient between the differential waveform and the template waveform is obtained for each parameter value, and then the phase is obtained in the fifth step. The position information of the mark is detected by obtaining the parameter value having the largest number of relationships, that is, the relative positional relationship between the differential waveform and the template waveform. Therefore, the position of the mark can be detected with high accuracy.

【0016】

The second position detection method of the present invention is a position detection method for detecting the position of a mark (MX, MY) formed on an object (W), and is a first step of imaging the mark; The signal waveform obtained in one step is subjected to a predetermined machining process to obtain at least one machining waveform in the second step; the signal waveform obtained in the first step and the signal waveform obtained in the second step are obtained. A third step of obtaining mark information regarding the position of the mark based on each processing waveform; and detecting the position information of the mark based on a plurality of mark information among the mark information obtained in the third step. This is a position detection method including the fourth step.

【0017】

According to this, the raw waveform of the imaging signal is obtained in the first step, at least one processed waveform of the imaging signal is obtained in the second step, and the raw waveform and at least one processed waveform are obtained in the third step, respectively. Based on this, mark information regarding the mark position such as the estimated mark position is obtained. Then, in the fourth step, the position information of the mark is detected based on a plurality of mark information among the obtained mark information. Therefore, the waveform used for detecting the mark position information is appropriately selected according to the mode of the noise signal superimposed on the image pickup signal, and the mark position information is detected using the selected waveform. Regardless of the mode, the position of the mark can be detected with high accuracy. The plurality of waveforms used for detecting the position information of the mark may or may not include a raw waveform.

【0018】

In the second position detection method of the present invention, the processing waveform obtained in the second step can be a waveform having a signal intensity distribution different from the signal waveform obtained in the first step.

【0019】

Further, in the second position detection method of the present invention, the signal waveform may be subjected to a process of changing the distribution of frequency components of the signal waveform as the predetermined processing process in the second step. , A differential waveform of at least a predetermined order of the signal waveform may be obtained.

【0020】

Here, at least one processed waveform can be a plurality of differential waveforms up to the predetermined floor. In such a case, the mark position information can be detected in consideration of the mark information obtained from each of the differential waveforms of a plurality of floors, in which the influence of the mark position information detection error differs depending on the mode of noise superimposed on the imaging signal. Therefore, the mark position information can be detected with high accuracy.

【0021】

Further, in the second position detection method of the present invention, the position of the mark can be detected by the weighting calculation of the plurality of mark information in the fourth step. In such a case, since the mark position is calculated by appropriately setting weights for each of the plurality of mark information, the mark position can be detected with high accuracy regardless of the mode of noise superimposed on the imaging signal.

【0022】

Here, the weight of each of the plurality of mark information used in the weighting operation can be obtained based on the plurality of mark information and the reference mark information obtained in advance. In such a case, the weight of each of the plurality of mark information is obtained based on the relationship between the reference mark information obtained in advance with high accuracy and the plurality of mark information obtained for each waveform, so that the mark position can be obtained with high accuracy. Can be detected.

【0023】

Further, the third step is a template for each of the signal waveform of the mark and an arbitrary processing waveform in the at least one processing waveform, and each of the signal waveform of the mark and an arbitrary processing waveform in the at least one processing waveform. The fifth step of obtaining the correlation coefficient at each relative position while changing the relative positional relationship with the waveform; based on the relative positional relationship at which the correlation coefficient is the largest, the signal waveform of the mark and at least one of the above. The sixth step of obtaining the estimated position of the mark, which is the mark information for each of the arbitrary processing waveforms in the processing waveform, can be included. In such a case, since the estimated position of the mark when each of the signal waveform of the mark and an arbitrary processed waveform in at least one processed waveform is used is obtained by template matching, the estimated position of the mark with high reliability is obtained. As a result, the position information of the mark can be detected with high accuracy.

【0024】

In the position detection method of the present invention in which the above weight calculation is performed, in the fourth step, all of the signal waveform and the processing waveform obtained in the second step are used for detecting the position information of the mark. It can be a waveform for detection. In such a case, since various waveforms are used and the mark position is calculated by appropriately setting weights for each mark information obtained from each waveform, the mark position is calculated with high accuracy regardless of the mode of noise superimposed on the imaging signal. The position of the mark can be detected.

【0025】

Further, the weight of the plurality of mark information can be obtained based on the same number of reference mark information as the number of the position detection waveforms. In such a case, since the number of the plurality of mark information and the number of the reference mark information are the same, the weight of each of the plurality of mark information used at the time of detecting the position of the mark is uniquely obtained.

【0026】

Further, the weights of the plurality of mark information can be statistically obtained based on a number of the reference mark information larger than the number of the position detection waveforms. In such a case, the weights of the plurality of mark information used when detecting the position of the mark are obtained by effectively utilizing the obtained plurality of mark information, so that the weights of the plurality of mark information can be accurately obtained. You can ask.

【0027】

In the second position detection method of the present invention, in the fourth step, one waveform estimated to be the mark information closest to the reference mark information is determined as the position detection waveform, and the determined position detection waveform is used. The position of the mark can be detected based on the waveform. In such a case, since the mark position is detected based on the waveform estimated to be most suitable for position detection, the mark position can be detected quickly while ensuring the detection accuracy.

【0028】

The first position detection device of the present invention is a position detection device that detects the position information of a mark (MX, MY) formed on an object (W), and is an imaging device that images a region on the subject. (AS); With the differential calculation device (32) that obtains the differential waveform of the predetermined order of the signal waveform of the mark obtained as a result of imaging by the imaging device; the correlation between the differential waveform and the predetermined template waveform. Based on this, it is a position detection device including a position calculation device (33) that detects the position information of the mark.

【0029】

According to this, the imaging signal (raw waveform) obtained by the imaging device imaging the mark is differentiated by the differential arithmetic unit to obtain a differential signal of a predetermined order. Then, the position calculation device detects the position information of the mark by performing template matching between the obtained differential signal and the template waveform. That is, the position information of the mark can be detected by using the first position detection method of the present invention. Therefore, since the position of the mark formed on the object can be detected by the first position detection method of the present invention, low-frequency noise is superimposed on the image pickup signal of the mark, and the mark position information is accurately obtained in the raw waveform template matching. Even when the detection is not possible, the position information of the mark can be detected with high accuracy.

【0030】

In the first position detection device of the present invention, the position calculation device changes the relative positional relationship between the differential waveform and the template waveform, and the correlation coefficient between the differential waveform and the template waveform at each relative position. It is possible to have a configuration including a correlation coefficient calculation device for calculating the mark and a position calculation device for calculating the position of the mark based on the relative positional relationship in which the correlation coefficient is the largest. In such a case, the correlation coefficient calculation device uses the relative positional relationship between the differential waveform and the template waveform as a parameter, obtains the correlation coefficient between the differential waveform and the template waveform for each parameter value, and then the position calculation device performs the position calculation device. , The position information of the mark is detected by obtaining the parameter value having the largest correlation coefficient, that is, the relative positional relationship between the differential waveform and the template waveform. Therefore, the position of the mark can be detected with high accuracy.

【0031】

The second position detection device of the present invention is a position detection device that detects the position information of a mark (MX, MY) formed on the object (W), and is an image pickup device (AS) that images the object. And; a waveform processing device (32) that performs a predetermined processing process on the signal waveform obtained as a result of imaging by the imaging device to obtain a processing waveform; and the signal waveform and the waveform processing device obtained. A mark information calculation device (33) for obtaining mark information regarding the position of the mark based on each of the processed waveforms; the mark based on a plurality of mark information among the mark information obtained by the mark information calculation device. It is a position detection device including a position calculation device (34) for detecting the position information of the above.

【0032】

According to this, the mark information calculation device is based on each of the image pickup signal (raw waveform) obtained by the image pickup device capturing the mark and the processed waveform obtained by the waveform processing device processing the image pickup signal. Obtains mark information regarding the mark position such as the estimated mark position for each waveform. Then, the position calculation device detects the position information of the mark based on a plurality of mark information among the obtained mark information. That is, the waveform used for detecting the position information of the mark is appropriately selected according to the mode of the noise signal superimposed on the image pickup signal, and the mark position is detected using the selected waveform. Therefore, since the position information of the mark formed on the object can be detected by the second position detection method of the present invention, the position information of the mark can be detected accurately regardless of the mode of noise.

【0033】

In the second position detection device of the present invention, the waveform processing device (a) performs a process of changing the distribution of the frequency component of the signal waveform as the predetermined processing process on the signal waveform. (B) As the predetermined processing process, a differential calculation device (32) for obtaining a differential waveform of at least a predetermined order of the signal waveform may be provided.

【0034】

The differential arithmetic unit may obtain differential waveforms of a plurality of floors up to the predetermined floor, and the position arithmetic unit may detect the position of the mark by weighting the plurality of mark information. it can. In such a case, it is obtained from each of the differential waveforms of a plurality of floors in which the influence of the mark position detection error differs depending on the mode of noise superimposed on the imaging signal, and the marks are appropriately weighted for each of the plurality of mark information obtained in this way. Since the position information is calculated, the position information of the mark can be detected with high accuracy regardless of the mode of noise superimposed on the imaging signal.

【0035】

Here, the position calculation device obtains the weight of each of the plurality of mark information used in the weighting calculation based on the plurality of mark information and the reference mark information obtained in advance (35). It can be configured to be provided. In such a case, the weights of the plurality of mark information are obtained based on the relationship between the reference mark information obtained with high accuracy and the plurality of mark information obtained for each waveform, so that the mark position information can be obtained with high accuracy. Can be detected.

【0036】

The exposure method of the present invention is an exposure method in which a predetermined pattern is transferred to a partition region (SA) on a substrate (W), and position information of a position detection mark (MX, MY) formed on the substrate is used. A sequence calculation step of detecting by the position detection method of the present invention, obtaining a predetermined number of parameters relating to the position of the partition region, and calculating the arrangement information of the partition region on the substrate; This is an exposure method including a transfer step of transferring the pattern to the partition region while controlling the position of the substrate based on the arrangement information of the compartment region.

【0037】

According to this, in the sequence calculation step, the position information of the position detection mark formed on the substrate is detected with high accuracy by using the position detection method of the present invention, and the partition on the substrate is based on the detection result. Calculate the array coordinates of the area. Then, in the transfer step, the pattern is transferred to the partition region while aligning the substrate based on the calculation result of the arrangement coordinates of the compartment region. Therefore, a predetermined pattern can be accurately transferred to the compartment region.

【0038】

The exposure apparatus of the present invention is an exposure apparatus that transfers a predetermined pattern to a partition region (SA) on a substrate (W), and is a stage apparatus (WST) that moves the substrate along a moving surface; It is an exposure apparatus including the position detection apparatus of the present invention that detects mark (MX, MY) position information on the substrate mounted on the apparatus. According to this, the position detection device of the present invention can accurately detect the position information of the mark on the substrate and thus the position information of the substrate. Therefore, the stage device can move the substrate based on the position information of the substrate obtained with high accuracy. As a result, the accuracy can be improved and a predetermined pattern can be transferred to the partition region on the substrate.

【0039】

The first recording medium of the present invention is a recording medium on which a control program executed by a position detection device that detects the position of a mark formed on an object is recorded, and is a signal obtained by imaging the mark. A differential waveform of a predetermined order of the waveform is obtained; the position information of the mark is detected based on the correlation between the differential waveform and the predetermined template waveform; the recording medium on which the control program is recorded.

【0040】

According to this, the position detection device can measure the position of the mark on the object by the second position detection method of the present invention by reading and executing the control program recorded on the recording medium. Therefore, even when low-frequency noise is superimposed on the image pickup signal of the mark and the mark position information cannot be detected accurately by the raw waveform template matching, the mark position information can be detected accurately.

【0041】

The second recording medium of the present invention is a recording medium on which a control program executed by a position detection device that detects the position of a mark formed on an object is recorded, and is a signal obtained by imaging the mark. A predetermined processing process is applied to the waveform to obtain at least one processing waveform; the mark information regarding the position of the mark is obtained based on the signal waveform and the at least one processing waveform, respectively; the determination is performed. The position information of the mark is detected based on a plurality of mark information among the marked mark information; the control program is recorded on the recording medium.

【0042】

According to this, the position detection device can read and execute the control program recorded on the recording medium, so that the position information of the mark on the object can be detected by the second position detection method of the present invention. Therefore, even when low-frequency noise is superimposed on the image pickup signal of the mark and the mark position cannot be detected accurately by the raw waveform template matching, the mark position information can be detected accurately.

【0043】

The device manufacturing method of the present invention is a device manufacturing method including a lithography step, characterized in that exposure is performed using the exposure method of the present invention in the lithography step. According to this, by performing exposure using the exposure method of the present invention, a predetermined pattern can be accurately transferred to the partition region, so that the productivity of a highly integrated device having a fine circuit pattern can be obtained. Can be improved.

【0044】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 9.

【0045】

FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to an embodiment of the present invention. The exposure apparatus 100 is a step-and-scan type projection exposure apparatus. The exposure device 100 includes an illumination system 10, a reticle stage RST holding a reticle R, a projection optical system PL, a wafer stage WST on which a wafer W as a substrate (object) is mounted, an alignment microscope AS as an image pickup device, and an apparatus. It is equipped with a main control system 20 etc. that controls the entire system.

【0046】

The illumination system 10 includes a light source, an illuminance uniforming optical system including a fly-eye lens, a relay lens, a variable ND filter, a reticle blind, a dichroic mirror, and the like (all not shown). The configuration of such a lighting system is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-112433. In this illumination system 10, the slit-shaped illumination region portion defined by the reticle blind on the reticle R on which the circuit pattern or the like is drawn is illuminated by the illumination light IL with substantially uniform illuminance.

【0047】

The reticle R is fixed on the reticle stage RST by, for example, vacuum adsorption. Here, the reticle stage RST is an optical axis of the illumination system 10 (the optical axis of the projection optical system PL described later) for positioning the reticle R by a reticle stage drive unit (not shown) consisting of a magnetically levitated two-dimensional linear actuator. It can be driven minutely in the XY plane perpendicular to AX), and can be driven at a specified scanning speed in a predetermined scanning direction (here, the Y direction). Further, in the present embodiment, since the magnetic levitation type two-dimensional linear actuator includes a Z drive coil in addition to the X drive coil and the Y drive coil, it can be driven minutely in the Z direction as well.

【0048】

The position of the reticle stage RST in the stage moving surface is constantly detected by the reticle laser interferometer (hereinafter referred to as reticle interferometer) 16 through the moving mirror 15 with a resolution of, for example, about 0.5 to 1 nm. The position information (or speed information) RPV of the reticle stage RST from the reticle interferometer 16 is sent to the stage control system 19, and the stage control system 19 is the reticle stage drive unit (not shown) based on the position information RPV of the reticle stage RST. Drive the reticle stage RST via. The position information RPV of the reticle stage RST is also sent to the main control system 20 via the stage control system 19.

【0049】

The projection optical system PL is arranged below the reticle stage RST in FIG. 1, and the direction of its optical axis AX is the Z-axis direction. As the projection optical system PL, a refracting optical system having a predetermined reduction magnification (for example, 1/5 or 1/4) with telecentricity on both sides is used. Therefore, when the illumination area of the reticle R is illuminated by the illumination light IL from the illumination optical system, the illumination light IL passing through the reticle R causes the circuit of the reticle R in the illumination area via the projection optical system PL. A reduced image (partially inverted image) of the pattern is formed on the wafer W on which the resist (photosensitive agent) is coated on the surface.

【0050】

The wafer stage WST is arranged on the base BS at the lower side in FIG. 1 of the projection optical system PL, and the wafer holder 25 is placed on the wafer stage WST. The wafer W is fixed on the wafer holder 25 by, for example, vacuum suction. The wafer holder 25 can be tilted in any direction with respect to the plane orthogonal to the optical axis of the projection optical system PL by a drive unit (not shown), and can be finely moved in the optical axis AX direction (Z direction) of the projection optical system PL. ing. Further, the wafer holder 25 can also perform a minute rotation operation around the optical axis AX.

【0051】

The wafer stage WST not only moves in the scanning direction (Y direction), but also moves in the direction perpendicular to the scanning direction (X) so that a plurality of shot regions on the wafer W can be positioned in an exposure region conjugate to the illumination region. It is configured to be movable in the direction as well, and performs a step-and-scan operation that repeats the operation of scanning and exposing each shot area on the wafer W and the operation of moving to the exposure start position of the next shot. Do. This wafer stage WST is driven in the XY two-dimensional direction by the wafer stage drive unit 24 including a motor and the like.

【0052】

The position of the wafer stage WST in the XY plane is constantly detected by the wafer laser interferometer 18 via the moving mirror 17 with a resolution of, for example, about 0.5 to 1 nm. The position information (or speed information) WPV of the wafer stage WST is sent to the stage control system 19, and the stage control system 19 controls the wafer stage WST based on this position information WPV. The position information WPV of the wafer stage WST is also sent to the main control system 20 via the stage control system 19.

【0053】

The alignment microscope AS is an off-axis alignment sensor arranged on the side surface of the projection optical system PL. This alignment microscope AS outputs the imaging result of the alignment mark (wafer mark) attached to each shot region on the wafer W. The imaging result is sent to the main control system 20 as imaging data IMD.

【0054】

The alignment marks include, for example, the marks MX and Y for detecting the position in the X direction as alignment marks formed on the street line around the shot area SA on the wafer W as shown in FIG. 2 (A). The mark MY for detecting the direction position is used. As each mark MX and MY, for example, a line and space mark having a periodic structure in the detection position direction can be used as represented by the enlarged mark MX in FIG. 2 (B). The alignment microscope AS outputs the imaging data IMD, which is the imaging result, toward the main control system 20 (see FIG. 1). Although the line and space mark with five lines is shown in FIG. 2 (B), the number of lines in the line and space mark adopted as the mark MX (or mark MY) is limited to five. It may be another number instead of being used. Further, in the following description, when the marks MX and the mark MY are individually indicated, they are described as the mark MX (i, j) and the mark MY (i, j) according to the arrangement position of the corresponding shot area SA. And.

【0055】

As shown in the XZ cross section of FIG. 3A, the line pattern 53 and the space pattern 54 are alternately formed in the X direction on the surface of the base layer 51 in the mark MX forming region on the wafer W, and the line pattern is formed. The resist layer covers 53 and the space pattern 54. The material of the resist layer is, for example, a positive resist material or a chemically amplified resist, and has high light transmittance. Further, the material of the base layer 51 and the material of the line pattern 53 are different from each other, and generally the reflectance and the transmittance are different from each other. In the present embodiment, the material of the line pattern 53 has a high reflectance, and the material of the base layer 51 has a higher reflectance than the material of the line pattern 53. It is assumed that the upper surfaces of the base layer 51, the line pattern 53, and the space pattern 54 are substantially flat.

【0056】

At this time, when the illumination light is irradiated from above and the image due to the reflected light in the formation region of the mark MX is observed from above, the X-direction distribution of the light intensity I in the image is shown in FIG. 3 (B) by design. Will be. That is, in the observation image, the light intensity is the largest and constant at the position corresponding to the upper surface of the base layer 51, the light intensity is the next largest and constant at the position corresponding to the upper surface of the line pattern 53, and the line pattern 53. The light intensity changes in a J-shape (or a letter) between the upper surface of the base layer 51 and the upper surface of the base layer 51. In this embodiment, the waveform shown in FIG. 3 (B) is used as a raw waveform template waveform XT.⁽⁰⁾It is adopted as (X). Then, the differential waveform of the template waveform XT (X) is adopted as the template waveform of the differential waveform of the raw waveform. Among such template waveforms, the template waveform d (XT (X)) / dX of the first derivative waveform and the template waveform d of the second derivative waveform²(XT (X)) / dX²Is typically shown in FIGS. 3 (C) and 3 (D).

【0057】

The mark MY is also configured in the same manner as the mark MX, except that the arrangement direction of the line pattern and the space pattern is the Y direction.

【0058】

In recent years, with the miniaturization of semiconductor circuits, a process of flattening the surface of each layer formed on the wafer W (flattening process) has been adopted in order to form a finer circuit pattern more accurately. Is becoming. The most prominent of these is the CMP (Chemical & Mechanical Polishing) process, in which the surface of a film formed is polished and the surface of the film is almost completely flattened. Such a CMP process is often applied to an interlayer insulating film (dielectric such as silicon dioxide) between wiring layers (metals) of a semiconductor integrated circuit.

【0059】

Recently, for example, an STI (Shallow Trench Isolation) process has been developed in which a shallow groove having a predetermined width is formed to insulate adjacent fine elements from each other and an insulating film such as a dielectric is embedded in the groove. In this STI process, the surface of the layer in which the insulator is embedded is flattened by a CMP process, and then polycrystalline silicon (hereinafter referred to as polysilicon) is formed on the surface. An example in which another pattern is formed at the same time with respect to the mark MX formed through such a step will be described with reference to FIGS. 4 (A) to 4 (E).

【0060】

First, as shown by the cross-sectional view in FIG. 4 (A), the mark MX (recess and space portion 54 corresponding to the line portion 53) and the circuit pattern 59 (more accurately) are placed on the silicon wafer (base material) 51. Is formed with a recess 59a).

【0061】

Next, as shown in FIG. 4 (B), silicon dioxide (SiO) was placed on the surface 51a of the wafer 51.₂An insulating film 60 made of a dielectric such as) is formed. Subsequently, by applying a CMP process to the surface of the insulating film 60, the clearing film 60 is removed and flattened until the surface 51a of the wafer 51 appears as shown in FIG. 4 (C). As a result, in the circuit pattern region, the circuit pattern 59 in which the insulator 60 is embedded in the recess 59a is formed, and in the mark MX region, the mark MX in which the green body 60 is embedded in the plurality of line portions 53 is formed.

【0062】

Next, as shown in FIG. 4D, a polysilicon film 63 is formed on the upper layer of the surface 51a of the wafer 51, and the photoresist PR is applied on the polysilicon film 63.

【0063】

When the mark MX on the wafer 51 shown in FIG. 4 (D) is observed using the alignment microscope AS, no unevenness reflecting the mark MX of the lower layer is formed on the surface of the polysilicon layer 63. Further, the polysilicon layer 63 does not transmit a luminous flux in a predetermined wavelength range (visible light of 550 nm to 780 nm). For this reason, the mark MX cannot be detected by the alignment method that uses visible light as the detection light for alignment, or the amount of detected light is reduced by the alignment method in which visible light occupies most of the detection light for alignment. , The detection accuracy may decrease.

【0064】

Further, in FIG. 4D, a metal film (metal layer) 63 may be formed instead of the polysilicon layer 63. In this case, no unevenness reflecting the alignment mark of the lower layer is formed on the surface of the metal layer 63. Further, since the detection light for alignment usually does not pass through the metal layer, there is a possibility that the mark MX cannot be detected.

【0065】

Therefore, when observing the wafer 51 (the wafer shown in FIG. 4D) on which the polysilicon layer 63 is formed through the CMP process as described above with the alignment microscope AS, the wavelength of the alignment detection light. If switching (selection or arbitrary setting) is possible, set the wavelength of the alignment detection light to the detection light having a wavelength other than visible light (for example, infrared light having a wavelength in the range of about 800 nm to about 1500 nm). , Mark MX should be observed.

【0066】

If the wavelength of the alignment detection light cannot be selected, or if the metal layer 63 is formed on the wafer 51 that has undergone the CMP process, the mark MX portion is as shown in FIG. 4 (E). The metal layer 63 (or polysilicon layer 63) in the region corresponding to the above may be peeled off with a photolithography, and then observed by the alignment microscopic competition AS.

【0067】

The mark MY can also be formed by interposing a CMP process in the same manner as the mark MX described above.

【0068】

As shown in FIG. 5, the main control system 20 includes a main control device 30 and a storage device 40. The main control device 30 includes a control device 39 that controls the operation of the exposure device 100 by supplying stage control data SCD to the stage control system 19, and an imaging data collecting device 31 that collects imaging data from the alignment microscope AS. , The differential arithmetic unit 32 as a waveform processing device for obtaining the differential waveform of the 1st to P (for example, P = 2) order of the raw waveform in the imaging data collected by the imaging data collecting device 31, and the raw waveform and the differential waveform. Estimated position calculation device 33 as a mark information calculation device for obtaining an estimated mark position which is mark information regarding a position for each waveform based on the above, and a position for obtaining the positions of alignment marks MX and MY based on the estimated mark position for each waveform. It is composed of an arithmetic unit 34. Then, the position calculation device 34 is a weight calculation device 35 that calculates the weight of each estimated mark position based on the estimated mark position and the reference mark position for each waveform, and the weight information obtained by the weight calculation device 35. It is equipped with a position calculation device 36 that calculates the positions of the alignment marks MX and MY based on the estimated mark position for each waveform. In addition, the storage device 40 contains a template waveform storage area 41 for storing raw waveform and differential waveform template waveform data, and QX (> P + 1) alignment marks MX (i)._R, j_R) Preliminarily determined reference X position data DX_R(R = 1 ~ QX) and QY (> P + 1) alignment marks MY (i)_T, j_T) Preliminarily obtained reference Y position data DY_TReference mark position storage area 42 for storing (T = 1 to QY), imaging data storage area 43, differential waveform storage area 44, estimated position storage area 45, weight storage area 46, and mark position storage area 47. And have. In FIG. 5, the data flow is indicated by a solid line arrow, and the control flow is indicated by a dotted line arrow. The operation of each device of the main control system 20 will be described later.

【0069】

In the present embodiment, the main control device 30 is configured by combining various devices as described above, but the main control device 30 is configured as a computer system, and each of the above devices constituting the main control device 30. It is also possible to realize the function by a program built in the main controller 30.

【0070】

Further, when the main control device 30 is configured as a computer system, all the programs for realizing the functions described later of the above-mentioned devices constituting the main control device 30 may be built in the main control device 30 in advance. , Not necessarily required. For example, as shown by the dotted line in FIG. 1, a storage medium 91 as a recording medium in which the program is stored is prepared, the program contents can be read from the storage medium 91, and the storage medium 91 can be attached and detached. The reading device 90 is connected to the main control system 20, and the program content required for the main control system 20 to realize the function from the storage medium 91 loaded in the reading device 90 (for example, the program content for performing the processing of FIG. 5). ) Can be read and configured to execute the program.

【0071】

Further, the main control system 20 can read the program contents from the storage medium 91 loaded in the reading device 90 and install them internally. Further, the program contents required for realizing the functions can be installed in the main control system 20 via the communication network using the Internet or the like.

【0072】

The storage medium 91 includes a magnetic storage medium (magnetic disk, magnetic tape, etc.), an electrically storage medium (PROM, RAM with battery backup, EEPROM, other semiconductor memory, etc.), and magneto-optically. Those that are stored in various storage forms, such as those that are stored (magneto-optical disk, etc.) and those that are electromagnetically stored (digital audio tape (DAT), etc.), can be adopted.

【0073】

As described above, by configuring the storage medium that stores the program contents to realize the functions so that it can be used or installed, the program contents can be modified later and the performance can be improved. Will be able to be easily upgraded.

【0074】

Returning to FIG. 1, the exposure optics supplies the exposure apparatus 100 with an imaging luminous flux for forming a plurality of slit images toward the best imaging surface of the projection optical system PL from an oblique direction with respect to the optical axis AX direction. The oblique incident type multipoint focus detection system including the system 13 and the light receiving optical system 14 that receives each reflected light flux on the surface of the wafer W of the imaged luminous flux through a slit supports the projection optical system PL. It is fixed to the support part (not shown). As the multipoint focus detection system (13, 14), for example, a system having the same configuration as that disclosed in Japanese Patent Application Laid-Open No. 5-190423 is used, and the stage control system 19 is the multipoint focus detection system (13). , 14) drives the wafer holder 25 in the Z direction and the tilt direction based on the wafer position information.

【0075】

In the exposure apparatus 100 configured as described above, the array coordinates of the shot region on the wafer W are detected as follows. As a premise for detecting the array coordinates of the shot area, the marks MX (i, j) and MY (i, j) are already on the wafer W in the process up to the previous layer (for example, the process of the first layer). It shall be formed. Further, the wafer W is loaded on the wafer holder 25 by a wafer loader (not shown), and the movement of the wafer W via the stage control system 19 by the main control system 20 causes each mark MX (i, It is assumed that coarse precision alignment (pre-alignment) has already been performed so that j) and MY (i, j) can be inserted. Such pre-alignment is used for observing the outer shape of the wafer W, observing the marks MX (i, j), MY (i, j) in a wide field of view, and position information (or velocity information) from the wafer interferometer 18. Based on this, it is performed by the main control system 20 (more specifically, the control device 39) via the stage control system 19. In addition, three or more X alignment marks MX (i) that are measured to detect the array coordinates of the shot area and are not aligned by design._m, j_m) (M = 1 ~ M; M 3, M QX), and 3 or more Y alignment marks MY (i) that do not line up in a straight line by design_n, j_n) (N = 1 ~ N; N 3, N QY) is assumed to have already been selected. However, the total number of selected marks (= M + N) must be greater than six.

【0076】

Also, X Alignment Mark MX (i_m, j_mMark MX (i) in)₁, j₁) ~ MX (i_QX, j_QX) Reference X position data DX₁~ DX_QX, And Y alignment mark MY (i_n, j_n) Mark MY (i)₁, j₁) ~ MY (i)_QY, j_QY) Reference Y position data DY₁~ DY_QYIs already stored in the reference mark position storage area 42. Reference X position data DX₁~ DX_QXAnd reference Y position data DY₁~ DY_QYMay use a value measured in advance by another measurement, or may use a value obtained by calculation from design data or the like.

【0077】

In addition, the template waveform XT (X) related to the raw waveform of the imaging result of the X alignment mark MX (hereinafter, "XT"⁽⁰⁾(X) ), and the template waveform d (XT (X)) / dX, ..., d related to the 1st to Pth order differential waveforms of the raw waveform.^P(XT (X)) / dX^P(Hereafter, "XT⁽¹⁾(X), ..., XT^(P)(X) ), and the template waveform YT (Y) related to the raw waveform of the imaging result of the Y alignment mark MY (hereinafter, YT .⁽⁰⁾(X) ), and the template waveform d (YT (Y)) / dY, ..., d related to the derivative waveforms of the 1st to Pth orders of the raw waveform.^P(YT (Y)) / dY^P(Hereafter, "YT⁽¹⁾(Y), ..., YT^(P)(Y) ) is assumed to have already been stored in the template waveform storage area 41. In this embodiment, the template waveform XT⁽⁰⁾(X) ~ XT^(P)(X), YT⁽⁰⁾(Y) ~ YT⁽^P)Although (Y) is obtained by using the design value in advance, it may be obtained by adding the mark imaging result up to that point to the design value.

【0078】

Hereinafter, the detection of the arrangement coordinates of the shot region on the wafer W will be described with reference to other drawings as appropriate, based on the flowchart shown in FIG.

【0079】

First, the mark MX (i) selected in step 201 of FIG._m, j_m), MY (i_n, j_nThe first mark in) (X alignment mark MX (i)₁, j₁) And) move the wafer W so that it is the imaging position by the alignment microscope AS. Such movement is performed by the main control system 20 (more specifically, the control device 39) under the control of the stage control system 19.

【0080】

Subsequently, in step 202, the alignment microscope AS, under the control of controller 39, marks the mark MX (i).₁, j₁) Is imaged. Then, as described above, the imaging data IMD, which is the imaging result by the alignment microscope AS, is captured by the imaging data collecting device 31 in response to the instruction from the control device 39 and stored in the imaging data storage area 43. Imaging data IMD is collected.

【0081】

Next, in step 203, the differential arithmetic unit 32 reads the imaging data IMD from the imaging data storage area 43 under the control of the control device 39, and the imaged mark MX (i) is captured.₁, j₁) Signal intensity distribution (light intensity distribution) on multiple (for example, 50) scanning lines in the X direction near the center with respect to the Y direction₁(X) ~ I₅₀Extract (X). Then, according to the following equation (1), the waveform of the signal intensity distribution in the average X direction, that is, the raw waveform I (X) (hereinafter, "I"⁽⁰⁾(X) ).

【0082】

[Number 1]

<img file="JP2001237177A_D0001.tif" />【0083】

Raw waveform obtained in this way I⁽⁰⁾(X) is the signal intensity distribution I₁(X) ~ I₅₀The high-frequency noise that is superimposed on each of (X) is reduced. Raw waveform obtained in this way I⁽⁰⁾(X) is shown in Figure 7 (B).

【0084】

Subsequently, the differential arithmetic unit 32 uses the raw waveform I.⁽⁰⁾Differentiation is performed as a process for processing (X), and the raw waveform I as shown in FIGS. 7 (C) and 7 (D).⁽⁰⁾Derivative waveform as a processed waveform with a different form (signal strength form, etc.) from (X) dI (X) / dX, ..., d^PI (X) / dX^P(Hereafter, "I⁽¹⁾(X), ..., I^(P)(X) ) is calculated. Derivative waveform obtained in this way I⁽¹⁾(X) ~ I^(P)First-order differential waveform in (X) I⁽¹⁾(X) and second derivative waveform I⁽²⁾(X) is typically shown in FIGS. 7 (C) and 7 (D).

【0085】

Then, the differential arithmetic unit 32 uses the raw waveform I.⁽⁰⁾(X) and differential waveform I⁽¹⁾(X) ~ I^(P)(X) is stored in the differential waveform storage area 44.

【0086】

Next, in step 204, the estimation position calculation device 33 controls the waveform I under the control of the control device 39.^(p)Template waveform XT for each of (X) (p = 0 ~ P)^(p)Perform template matching using (X) and waveform I^(p)Mark MX (i) required for each (X)₁, j₁) Estimated X position X₁^(p)Is calculated. In the following description, the estimated X position and the estimated Y position described later are also collectively referred to as "estimated mark position".

【0087】

In calculating the estimated X position, the waveform I^(p)(X) and template waveform XT^(p)Correlation coefficient CR with (X + δX)_pFind (δX) and find the value of the parameter δX that maximizes it. This correlation coefficient CR_p(δX) is the waveform I^(p)The average value of (X) is μ_pAnd template waveform XT^(p)The average value of (X) is μT_pAs a result, the predetermined domain XD related to the X position is obtained by the following equation (2).

【0088】

[Number 2]

<img file="JP2001237177A_D0002.tif" />【0089】

Here, mark the predetermined domain XD MX (i₁, j₁) Can be set to the entire area related to the X direction (hereinafter referred to as "entire area template matching"), and when template matching of a differential waveform is performed, each edge related to the X direction where a large peak exists in the differential waveform. It can also be an area for each part (hereinafter referred to as "partial template matching"). Correlation coefficient CR for global template matching_pMark MX (i) from the value δX that maximizes (δX) and the position information WPV of the wafer W described above.₁, j₁) Estimated X position X₁^(p)Is directly required. In the case of partial template matching, the correlation coefficient CR_pMark MX (i) from the value δX that maximizes (δX) and the position information WPV of the wafer W described above.₁, j₁The X position of each edge of) is obtained, and the mark MX (i) is obtained from these edge positions.₁, j₁) Estimated X position X₁^(p)Is required. In the case of partial template matching, it is not affected by noise superposition outside the domain XD, and the result is biased near the peak pole, so the true peak pole X The position can be obtained accurately.

【0090】

In this way, each waveform I^(p)Estimated position X obtained for each (X)₁^(p)Is stored in the estimated position storage area 45 by the estimated position calculation device 32.

【0091】

Next, it is determined whether or not the calculation of the estimated mark position for each waveform of the raw waveform and the differential waveform is completed for all the marks selected in step 205. In the above, one mark MX (i₁, j₁) Only the estimated mark position, i.e. mark MX (i)₁, j₁) Only the calculation of the estimated X position is completed, so the determination in step 205 is negative, and the process shifts to step 206.

【0092】

In step 206, the control device 39 moves the wafer W to a position where the next mark is in the imaging field of view of the alignment microscope AS. The movement of the wafer W is performed by the control device 39 controlling the wafer driving device 24 via the stage control system 19 to move the wafer stage WST.

【0093】

After that, in step 205, the above-mentioned mark MX (i) is described until it is determined that the estimated mark positions have been calculated for all the selected marks.₁, j₁), Mark MX (i)_m, j_m) (M = 2 ~ M) Estimated X position X_m^(p)(p = 0 ~ P) and mark MY (i)_n, j_n) (N = 1 ~ N) Estimated Y position Y_n^(p)Is calculated. In this way, the estimated mark positions of all the selected marks are calculated and stored in the position information storage area 43, and when a positive determination is made in step 205, the process proceeds to step 207.

【0094】

In step 207, the weight calculation device 35 uses the mark MX (i)._m, j_m) Weight WX for each estimated X position obtained from the raw waveform and differential waveform for each (m = 1 ~ M)^(p)(p = 0 ~ P) and mark MY (i)_n, j_n) Weight WY for each estimated Y position obtained from the raw waveform and differential waveform for each (n = 1 to N)^(p)Is calculated as follows.

【0095】

First, the weight calculation device 35 uses the weight WX.^(p)With each as an unknown, this weight WX^(p)Mark MX (i) calculated using₁, j₁) ~ MX (i_QX, j_QX) Each X position X_RLet (R = 1 ~ QX) be the following equation (3).

【0096】

[Number 3]

<img file="JP2001237177A_D0003.tif" />【0097】

Subsequently, the weight calculation device 35 reads the X position X from the reference mark position storage area 42._RReference X position DX_RDegree of variation SX against, weight WX^(p)With the unknown number, it is calculated by the following equation (4).

【0098】

[Number 4]

<img file="JP2001237177A_D0004.tif" />【0099】

Then, the weight calculation device 35 uses the weight WX so that the degree of variation SX is minimized.^(p⁾To ask. Specifically, Eq. (4) is expressed by each weight WX.^(p)By solving the simultaneous equations obtained by partially differentiating with and setting each partial differential result to 0, the optimum weight WX^(p)Calculate each value of.

【0100】

Continue to Mark MY (i)_n, j_n) Weight WY for each estimated Y position obtained from the raw waveform and differential waveform for each (n = 1 to N)^(p), The above weight WX^(p)Obtain in the same way as. That is, the mark MY (i) calculated by the weighting operation.₁, j₁) ~ MY (i)_QY, j_QY) Each Y position Y_TReference Y position DY of (T = 1 ~ QY)_TWeight WY that minimizes the degree of variation SY with respect to^(p)To ask.

【0101】

The weight WX thus obtained^(p)And WY^(p)Is stored in the weight information storage area 46 by the weight calculation device 35.

【0102】

Next, in step 208, the position calculation device 36 determines the mark MX (i) from the estimated position storage area 45._m, j_m) (M = 1 ~ M) Estimated X position X_m^(p)(p = 0 ~ P) and mark MY (i)_n, j_n) (N = 1 ~ N) Estimated Y position Y_n^(p)Is read, and the weight WX is read from the weight storage area 46.^(p)And WY^(p)Is read. Continuing, the weight WX is no longer unknown^(p)And estimated X position X_m^(p)Using and, by the same equation as in equation (3), mark MX (i)_m, j_m) X position X_mAnd in the same way, the weight WY, which is no longer an unknown^(p)And estimated Y position Y_n^(p)And use the mark MY (i_n, j_n) Y position Y_nIs calculated. Then, the position calculation device 36 uses the calculated mark MX (i)._m, j_m) X position X_mAnd mark MY (i_n, j_n) Y position Y_nIs stored in the mark position storage area 47.

【0103】

Thus, Mark MX (i_m, j_m) X position X_mAnd mark MY (i_n, j_n) Y position Y_nDetection is completed.

【0104】

After that, the control device 39 starts from the mark position storage area 47 and marks MX (i)._m, j_m) (M = 1 ~ M) X position X_m, And Mark MY (i_n, j_n) Y position Y of (n = 1 ~ N)_nIs read out, and the parameter (error parameter) value for calculating the array coordinates of the shot region SA on the wafer W is calculated by, for example, the statistical calculation disclosed in Japanese Patent Application Laid-Open No. 61-44429. Then, under the control of the control device 39, the slit-shaped illumination region (the center is almost the same as the optical axis AX) in the reticle R is illuminated while using the shot region array obtained by using the calculated parameter values. While illuminated by the optical IL, the wafer W and the reticle R are moved in opposite directions along the scanning direction (Y direction) at a speed ratio according to the projection magnification. As a result, the pattern in the pattern region of the reticle R is reduced and transferred onto the shot region on the wafer W.

【0105】

As described above, according to the present embodiment, the raw waveform of the imaging signal and the raw waveform thereof are subjected to the mode of noise superimposed on the imaging signals of the alignment marks MX and MY formed on the wafer W. Since the positions of the alignment marks MX and MY are detected using the differential waveform as the processed waveform, the positions of the alignment marks MX and MY can be detected accurately regardless of the mode of noise. Then, in the present embodiment, the array coordinates of the shot region SA (i, j) on the wafer W are calculated with high accuracy based on the positions of the alignment marks MX and MY obtained with high accuracy, and based on these calculation results. Since the wafer W can be aligned with high accuracy, the pattern formed on the reticle R can be accurately transferred to each shot region SA (i, j).

【0106】

The above weight WX^(p), WY^(p)For example, for the first wafer in an exposure lot, and for other wafers in the same exposure lot, the same weight WX as the first wafer.^(p), WY^(p)Can be applied to detect the position of the alignment mark. In addition, even if the exposure lot is different, the same weight WX is used for wafers processed by the same process.^(p), WY^(p)Can be applied. In addition, the weight WX for the first few wafers of the same lot or process^(p), WY^(p)It is also possible to obtain and apply their average value as a weight to other wafers in the same lot or the same process.

【0107】

Further, in the present embodiment, the estimated mark positions obtained for each of the raw waveform and the differential waveform are appropriately weighted, and the positions of the alignment marks MX and MY are detected by the weighting calculation, so that they are superimposed on the imaging signal. Regardless of the mode of noise generated, the positions of the alignment marks MX and MY can be detected with high accuracy.

【0108】

Further, in the present embodiment, since the weight of each estimated mark position obtained for each waveform is obtained based on the obtained estimated mark position and the reference mark position obtained in advance, a weighting operation by appropriate weighting is performed. The positions of the alignment marks MX and MY can be detected with high accuracy.

【0109】

Further, since the estimated mark position for each waveform is obtained by template matching, the estimated mark position with high estimation reliability can be obtained, and the positions of the alignment marks MX and MY can be detected with high accuracy.

【0110】

Further, in the present embodiment, the weight of each of the estimated mark positions used in the weighting calculation is based on the reference mark positions related to the alignment marks MX and MY, which are larger than the number of estimated mark positions obtained for each of the alignment marks MX and MY. Therefore, since it is obtained statistically, it is possible to accurately obtain the weight of each estimated mark position while utilizing the obtained information on the estimated mark position.

【0111】

In the above embodiment, a differential waveform is used as the waveform obtained by processing the raw waveform, but the present invention is not limited to this. As the process for processing the raw waveform, in addition to differentiating the raw waveform, for example, a filtering process (a process for changing the frequency component of the raw waveform) for the raw waveform can be used. As the filtering process, various methods such as known low-pass filtering, high-pass filtering, and filtering using a predetermined filtering function such as a SYNC function can be considered. In addition, the degree of filtering is not limited to one type, and can be performed to various degrees.

【0112】

In short, any processing can be performed if a processing waveform that is related to the raw waveform and has a waveform form different from that of the raw waveform is required. Any number of types of processing waveforms can be obtained. For example, in the above embodiment, two types of processing waveforms, a first-order differential waveform and a second-order differential waveform, are obtained as the processing waveforms. Then, the mark position information is obtained for each waveform (including the raw waveform), and the obtained mark position information is subjected to integrated calculation processing by a method such as a weighting calculation as described in the above-described embodiment. Therefore, the position information of the mark may be obtained.

【0113】

When performing the integrated arithmetic processing, the integrated arithmetic processing can be performed regardless of what kind of processing is performed on the processed waveform. For example, it is also possible to perform integrated calculation processing of the mark position information obtained from the above-mentioned raw waveform and the mark position information obtained from the first-order differential waveform. It is also possible to perform integrated calculation processing of the mark position information obtained from the first-order differential waveform and the mark position information obtained from the second-order differential waveform. Further, it is also possible to perform integrated calculation processing of the mark position information obtained from the differential waveform and the mark position information obtained from the processed waveform that has been processed differently from the differential processing (for example, low-pass filtering processing).

【0114】

In the above embodiment, the weight of each of the estimated mark positions used in the weighting calculation is set to the reference mark position related to the alignment mark MX, MY, which is larger than the number of the estimated mark positions obtained for each alignment mark MX, MY. Although it was obtained based on the above, it is also possible to make the number of reference mark positions the same as the number of estimated mark positions obtained for each of the alignment marks MX and MY. In such a case, the weights related to each estimated mark position can be uniquely obtained by solving the above equations (3) as simultaneous equations.

【0115】

Further, in the above embodiment, the positions of the alignment marks MX and MY are detected by using all of the estimated mark positions obtained for each of the alignment marks MX and MY, but the positions are selected from the obtained estimated mark positions. It is also possible to detect the positions of the alignment marks MX and MY using only the ones. As a method of selecting such an estimated mark position, for example, there is a method of selecting a method in which the difference from the corresponding reference mark position is equal to or less than a predetermined value. In addition, as a method of selecting the estimated mark position, one of the raw waveform and the differential waveform estimated to be the closest estimated mark position to the reference mark position as a result of comparison between the obtained estimated mark position and the reference mark position. A method of selecting a waveform can also be adopted.

【0116】

Further, when the mode of noise superimposed on the raw waveform is known to some extent, it is possible to detect the positions of the alignment marks MX and MY by using only the waveform for which the estimated mark position having a small influence of noise is required. .. Here, when the waveform to be used is a differential waveform, the edge portion where the signal level changes significantly in the raw waveform is emphasized, so the position of each edge is detected by using the above-mentioned partial template matching method. However, it is desirable to detect the positions of the alignment marks MX and MY from these edge positions. This enables, for example, position detection with reduced effects of low-frequency noise.

【0117】

Further, in the above embodiment, the case of the scanning exposure apparatus has been described, but the present invention has a reduction projection exposure apparatus using ultraviolet rays as a light source, a reduction projection exposure apparatus using soft X-rays having a wavelength of about 30 nm as a light source, and a wavelength. It can be applied to all types of wafer exposure equipment, liquid crystal exposure equipment, etc., such as X-ray exposure equipment that uses around 1 nm as a light source, exposure equipment that uses EB (electron beam) and ion beams. In addition, the step-and-repeat machine, the step-and-scan machine, and the step-and-stitching machine are not limited.

【0118】

Further, in the above embodiment, the case of the position detection of the alignment mark on the wafer and the alignment of the wafer in the exposure apparatus has been described, but the positioning and alignment to which the present invention is applied are the alignment on the reticle. It can also be used for mark detection, position detection, and reticle alignment, and is also an object in devices other than exposure equipment, such as object observation equipment using a microscope, factory assembly line, processing line, and inspection line. It can also be used for position detection of an object and alignment of the object in an object positioning device or the like.

【0119】

&lt;&lt; Manufacturing of Device &gt;&gt; Next, manufacturing of a device using the exposure apparatus and method of the present embodiment will be described.

【0120】

FIG. 8 shows a flowchart of production of devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin film magnetic heads, micromachines, etc.) according to the present embodiment. As shown in FIG. 8, first, in step 301 (design step), the function design of the device (for example, the circuit design of the semiconductor device, etc.) is performed, and the pattern design for realizing the function is performed. Subsequently, in step 302 (mask manufacturing step), a mask forming the designed circuit pattern is manufactured. On the other hand, in step 303 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

【0121】

Next, in step 304 (wafer processing step), an actual circuit or the like is formed on the wafer by a lithography technique using the mask and the wafer prepared in steps 301 to 303, as described later. Then, in step 305 (device assembly step), the wafer processed in step 304 is used for chipping. This step 305 includes steps such as an assembly step (dicing, bonding) and a packaging step (chip encapsulation).

【0122】

Finally, in step 306 (inspection step), an inspection such as an operation confirmation test and a durability test of the device manufactured in step 305 is performed. After going through these steps, the device is completed and shipped.

【0123】

FIG. 9 shows a detailed flow example of step 304 in the case of a semiconductor device. In FIG. 9, in step 311 (oxidation step), the surface of the wafer is oxidized. In step 312 (CVD step), an insulating film is formed on the wafer surface. In step 313 (electrode forming step), electrodes are formed on the wafer by thin film deposition. In step 314 (ion driving step), ions are driven into the wafer. Each of the above steps 311 to 314 constitutes a pretreatment step of each stage of the wafer process, and is selected and executed according to the processing required in each stage.

【0124】

When the pretreatment step is completed at each stage of the wafer process, the posttreatment step is executed as follows. In this post-treatment step, first, in step 315 (resist forming step), a photosensitive agent is applied to the wafer, and then in step 316 (exposure step), the mask is subjected to the exposure apparatus and exposure method of the embodiment described above. The circuit pattern is baked and exposed on the wafer. Next, in step 317 (development step), the exposed wafer is developed, and subsequently, in step 318 (etching step), the exposed member of the portion other than the portion where the resist remains is removed by etching. Then, in step 319 (resist removal step), the resist that has been etched and is no longer needed is removed.

【0125】

By repeating these pretreatment steps and posttreatment steps, multiple circuit patterns are formed on the wafer.

【0126】

As described above, a device in which a fine pattern is formed with high accuracy is manufactured with high mass productivity.

【0127】

[Effect of the invention]

As described above, according to the position detection method of the present invention, depending on the mode of noise superimposed on the image pickup signal of the mark formed on the object, the raw waveform and the differential waveform of the image pickup signal are appropriately used to form the mark. Since the position is detected, the position of the mark can be detected accurately regardless of the mode of noise.

【0128】

Further, according to the position detection device of the present invention, the position of the mark is detected by using the position detection method of the present invention, so that the mark position can be detected with high accuracy.

【0129】

Further, according to the exposure method of the present invention, the position of the position detection mark formed on the substrate is detected with high accuracy by using the position detection method of the present invention, and the substrate is aligned based on the detection result. Since the pattern is transferred to the compartmental area while performing the above, the predetermined pattern can be accurately and quickly transferred to the compartmentalized area.

【0130】

Further, according to the exposure apparatus of the present invention, the position of the position detection mark can be detected with high accuracy by the position detection apparatus of the present invention, so that the accuracy can be improved and a predetermined pattern can be obtained as a partition region on the substrate. Can be transferred to.

【0131】

Further, according to the recording medium of the present invention, an object is used by using the position detection method of the present invention by reading or installing the program contents recorded on the recording medium and executing the program contents. Since the position information of the upper mark can be detected, the position information of the mark can be detected with high accuracy.

【0132】

Further, according to the device manufacturing method of the present invention, in the lithography process, a predetermined pattern is transferred to the substrate by using the exposure method of the present invention, so that a device in which a fine pattern is formed with high accuracy can be manufactured. Can be done.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the schematic structure of the exposure apparatus of one Embodiment.

[Figure 2]

2 (A) and 2 (B) are diagrams for explaining an example of the alignment mark.

[Fig. 3]

3 (A) to 3 (D) are diagrams for explaining the template waveform related to the alignment mark.

[Fig. 4]

FIGS. 4 (A) to 4 (E) are diagrams for explaining a process in which marks are formed through a CMP process.

[Fig. 5]

It is a figure which shows the schematic structure of the main control system.

[Fig. 6]

It is a flowchart for demonstrating the position detection operation of a mark.

[Fig. 7]

7 (A) to 7 (D) are diagrams for explaining the imaging result of the alignment mark in one embodiment.

[Fig. 8]

It is a flowchart for demonstrating the device manufacturing method using the exposure apparatus of FIG.

[Fig. 9]

It is a flowchart of processing in the wafer processing step of FIG.

[Explanation of symbols]

32 ... differential arithmetic unit (waveform processing unit), 33 ... estimated position calculation device (mark information calculation device, correlation coefficient calculation device), 34 ... position calculation device, 35 ... weight calculation device, 36 ... mark position calculation device (position calculation device), 91 ... storage medium (recording medium), AS ... alignment microscope (imaging device), MX, MY ... alignment mark (mark, for position detection) Mark), SA ... Shot area (partition area), W ... Wafer (object, substrate), WST ... Wafer stage (stage device).