JP3339079B2 - Alignment apparatus, exposure apparatus using the alignment apparatus, alignment method, exposure method including the alignment method, device manufacturing method including the exposure method, device manufactured by the device manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sequentially aligning a plurality of processing regions (shot regions, chip patterns, etc.) regularly arranged on a substrate with respect to a predetermined reference position. The present invention relates to an alignment method suitable for an exposure apparatus for transferring a pattern of a mask used in a lithography process for manufacturing a semiconductor element or a liquid crystal display element onto a photosensitive substrate.

[0002]

2. Description of the Related Art In recent years, in an exposure apparatus such as a step-and-repeat method or a step-and-scan method, a wafer prober, or a laser repair apparatus, a plurality of chip patterns regularly (matrix-like) are arranged on a substrate. Each of the areas (shot areas) is defined as a predetermined reference point (for example, a processing point of various devices) in a stationary coordinate system (that is, an orthogonal coordinate system defined by two sets of laser interferometers) that defines the movement position of the substrate. ) Needs to be very precisely aligned. Particularly, in an exposure apparatus, when a substrate (semiconductor wafer, glass plate, or the like) is aligned with an exposure position of a pattern formed on a mask or a reticle (hereinafter, referred to as a reticle), defective products are generated in chips in a manufacturing stage. Therefore, it is desired that the positioning accuracy (alignment) is always maintained with high accuracy and stably so as to prevent a decrease in the yield due to the above.

Usually, in the lithography process, one
A circuit pattern (reticle pattern) of zero or more layers is superposed and exposed, but if alignment (superposition) accuracy between the layers is poor, inconvenience may occur in circuit characteristics.
That is, the chip does not satisfy the expected characteristics, and in the worst case, the chip becomes a defective product, which may lower the yield.
Therefore, in the exposure step, an alignment mark is previously attached to each of a plurality of shot areas on the wafer, and the mark position (coordinate value) is detected with reference to a reticle pattern to be overlaid and exposed. Thereafter, based on the mark position information, wafer alignment for positioning (positioning) one shot area on the wafer with respect to the reticle pattern is performed.

There are roughly two types of wafer alignment methods. One is a die-by-die (D / D) alignment method in which alignment is detected by detecting an alignment mark for each shot area on a wafer. . The other is a global alignment method in which each shot area is aligned by detecting alignment marks of only some shot areas on the wafer and determining the regularity of the shot arrangement. At present, a global alignment method is mainly used in a device manufacturing line in consideration of throughput. In particular, at present, for example, JP-A-61-44429 and JP-A-62
As disclosed in Japanese Patent No. 84516, etc., enhanced global alignment (E) that precisely specifies the regularity of shot arrangement on a wafer by a statistical method.
GA) is the mainstream.

The EGA method measures the coordinate positions of only a plurality of (three or more, usually about 10 to 15) shot areas selected in advance as a specific shot area in one wafer. After calculating the coordinate positions (shot arrays) of all the shot areas on the wafer from the measured values of the statistical processing (least square method or the like), the wafer stage is uniquely stepped according to the calculated shot arrays. It goes. The EGA method has an advantage that the measurement time is short and an averaging effect can be expected for random measurement errors.

Here, the statistical processing method performed in the EGA system will be briefly described. Now, m (m
(Xn, Yn) (n = 1, 2)
2,..., M), and the deviation from the designed array coordinates (Δ
Xn, ΔYn) for a linear model, ie,

[0007]

(Equation 1)

Assume that Further, the actual array coordinates (measured values) of each of the m sample shots are represented by (Δx _n , Δ
y _n ), the residual sum of squares E when this model is applied is expressed by the following equation.

[0009]

(Equation 2)

Therefore, parameters a, b, c, d, e, and f that minimize this equation may be obtained. In the EGA method, the array coordinates of all shot areas on a wafer are calculated based on the parameters a to f calculated as described above and the array coordinates in design. As described above, in the EGA method, the shot arrangement error on the wafer is treated as being linear. In other words, the EGA calculation is a linear first-order approximation. For this reason, there has been a problem that it is not possible to cope with local arrangement error fluctuation on the wafer, that is, non-linear factors. So, for example,
As disclosed in Japanese Patent Application Laid-Open No. 291133, at least three shot areas present in a local partial area (block) on a wafer are designated as sample shots, and their coordinate positions are obtained. EGA
By calculating (statistical calculation), the coordinate positions (shot arrays) of all shot areas in the block are calculated.
A so-called blocked EGA (B-EGA) system has been proposed. The B-EGA method is characterized in that the sample shot used in the EGA calculation is changed for each shot area to be aligned. For example, three or more shot areas are designated as sample shots in order from the closest to the shot area to be aligned, and each measurement value of the designated sample shot is used. This makes it possible to cope with a local variation (non-linearity) of the alignment error on the wafer.

[0011]

However, in the prior art as described above, if the processing of selecting a sample shot to be used in the EGA calculation for each shot area to be aligned is performed by a computer, the calculation amount for the processing is increased. Is a huge problem. Further, it is difficult to optimize the selection of the sample shot for each shot area in the block. Therefore, although the B-EGA method can cope with a local variation in the alignment error (non-linear distortion), the alignment accuracy obtained therefrom does not sufficiently satisfy the required accuracy. Further, in the B-EGA method, since the sample shots are changed for each shot area, the number of sample shots on one wafer greatly increases, so that the processing time for one wafer becomes longer and the throughput decreases. There is also a problem.

When a wafer is placed on a wafer stage via a holder (holding member), if the wafer is greatly warped by, for example, heat treatment, the peripheral portion of the wafer is attracted to the holder, but the central portion of the wafer is attracted to the holder. May float without being adsorbed by the holder. Therefore, the shot area on the wafer where the above phenomenon occurs, especially each shot area near the center, is apparently farther from the center of the wafer than the corresponding shot area on the wafer whose entire surface is attracted to the holder. That is, the image is relatively shifted in the direction (position shift).

Here, when the B-EGA method is applied to a wafer on which a non-linear distortion due to the above-mentioned phenomenon has occurred, if the portion of the wafer that is raised is clearly known, the non-linear It is possible to prevent the alignment accuracy from lowering to some extent in response to the distortion. However, in this case as well, the same problems as those described above (such as an increase in the amount of calculation and the number of sample shots) occur, and it is actually difficult to specify the part of the wafer that is floating (swelling). In other words, the B-EGA method cannot optimize the block division of a plurality of shot areas on a wafer, and thus it is difficult to obtain a desired alignment accuracy even if the B-EGA method is applied.

If a nonlinear approximation using, for example, a higher-order function is applied to a wafer having a nonlinear distortion, instead of the first-order approximation as in the EGA method, a decrease in alignment accuracy can be prevented. However, in this case, the number of sample shots must be significantly increased as compared with the EGA method, and there is a problem that it takes time for mark measurement and the throughput is reduced.

The present invention has been made in view of the above points, and even if the wafer has a local alignment error (non-linear distortion), the number of sample shots is small and the amount of calculation is small. An object of the present invention is to provide a positioning method capable of performing high-precision and high-speed alignment of all shot regions with respect to a predetermined reference position while suppressing the position.

[0016]

According to the first aspect of the present invention, each of a plurality of processing regions regularly formed on a substrate (W) in accordance with a design arrangement coordinate is used. An alignment device for positioning with respect to a predetermined reference position in a stationary coordinate system for defining a moving position of the substrate, wherein at least three specific processing regions (sample shots) on the substrate in the stationary coordinate system. Detecting means (17, 2) for detecting first coordinate position information on the coordinate position
0), a plurality of first coordinate position information regarding three specific processing area even been said at detected by the detecting means, the
A processing area on the substrate and each of the plurality of specific processing areas;
Processing area on the substrate based on information about the distance between
Each of the plurality of processing regions in the stationary coordinate system is weighted for each of the plurality of first coordinate position information and statistically operated (least square method, simple averaging process, or the like) on the plurality of weighted first coordinate position information. Calculating means (10) for calculating second coordinate position information relating to the coordinate position of the above, and setting means (10, 101) for setting the degree of weighting in the calculating means
And configured.

[0017]

According to the third aspect of the present invention, each of the plurality of processing regions regularly formed on the substrate (W) in accordance with the arrangement coordinates in the design is defined by a stationary coordinate system for defining the movement position of the substrate. Detecting at least three specific processing areas (sample shots) on the substrate with first coordinate position information on coordinate positions in the stationary coordinate system with an alignment device that aligns with a predetermined reference position in the substrate. Means (17, 20), for each processing area on the substrate, first distance information relating to a distance between the processing area and a predetermined point of interest predefined on the substrate; Performing weighting on each of the plurality of pieces of the first coordinate position information on the at least three specific processing areas detected by the detection unit, based on second distance information on a distance to a specific processing area; and Statistical calculation (least squares method, simple averaging process, or the like) is performed on the weighted plurality of pieces of the first coordinate position information to obtain second coordinates related to the coordinate positions of the plurality of processing regions in the stationary coordinate system. And an operation means (10) for calculating position information.

According to the thirteenth aspect of the present invention, each of the plurality of processing regions regularly arranged on the substrate (W) in accordance with the arrangement coordinates in the design is used to determine the moving position of the substrate. First alignment position information on coordinate positions on the stationary coordinate system of at least three specific processing regions (sample shots) among the plurality of processing regions, the alignment device performing alignment with respect to a predetermined reference position within And correction means (10, 18, 1) for correcting each of the first coordinate position information of the at least three specific processing regions based on the flatness of the substrate.
9) and performing a statistical operation (such as a least squares method or a simple averaging process) on the plurality of corrected first coordinate position information to obtain the stationary coordinate system of each of the plurality of processing regions on the substrate. Calculating means (10) for calculating second coordinate position information relating to the coordinate position above, and controlling the moving position of the substrate according to the second coordinate position information and the flatness of the substrate, whereby the plurality of processes are performed. Control means (11) for sequentially positioning each of the regions with respect to the reference position is provided.
In the invention according to claim 15, predetermined in each of a plurality of processing areas which are regularly arranged on the substrate (W) according to the arrangement coordinates of the design, the stationary coordinate system for defining the moving position of the substrate Selecting at least three processing regions from among the plurality of processing regions as specific processing regions (sample shots); and aligning the surface of the selected specific processing region with the substrate. On the stationary coordinate system of each of the at least three specific processing regions when the moving plane of the at least three specific processing regions is substantially parallel to a stationary plane (ie, a plane including a rectangular coordinate system defined by two sets of interferometers). Detecting means (17, 18, 19) for detecting first coordinate position information relating to the coordinate position in (1), and statistically calculating (least square method or simple flattening) the plurality of detected first coordinate position information. Computing means (10) for calculating second coordinate position information on a coordinate position on the stationary coordinate system of each of the plurality of processing regions on the substrate by performing A control means (1) for sequentially positioning each of the plurality of processing regions with respect to the reference position by controlling the moving position of the substrate in accordance with the amount of inclination of each processing region with respect to the moving plane of the substrate.
0, 11, 18, 19). Claim 18
In the invention described in the above, each of the plurality of processing regions regularly formed on the substrate (W) in accordance with the arrangement coordinates on the design is moved to a predetermined reference position in a stationary coordinate system that defines the movement position of the substrate. In the alignment method, the first coordinate position information regarding the coordinate position in the stationary coordinate system of at least three specific processing regions (sample shots) on the substrate is detected, and the detected at least 3 positions are detected. One of a plurality of said first coordinate position information about a specific processing area, the plurality of specific processing region on the substrate
Based on information about the distance between each of the processing areas
Weighting each of the processing regions on the substrate , and statistically calculating the weighted plurality of the first coordinate position information, thereby obtaining a second coordinate position for each of the plurality of processing regions in the stationary coordinate system. Two coordinate position information is calculated, and the degree of weighting used in this calculation is set. In the invention according to claim 19 , each of the plurality of processing regions regularly formed on the substrate (W) in accordance with the arrangement coordinates in design is defined by a predetermined position in a stationary coordinate system that defines a movement position of the substrate. In the alignment method for performing positioning with respect to the reference position, first coordinate position information on a coordinate position in the stationary coordinate system of at least three specific processing regions on the substrate is detected. A first distance information relating to a distance between the processing area and a predetermined point of interest predefined on the substrate; a second distance information relating to a distance between the point of interest and the specific processing area; Weighting each of the plurality of the first coordinate position information regarding the at least three specific processing regions detected in the detecting step, and calculating the weighted plurality of the first coordinate position information. By statistically calculating a target position information, it was decided to calculate the second coordinate position information for each of the coordinate positions of the plurality of processing regions in the stationary coordinate system. Further, in the invention according to claim 24 , each of the plurality of processing regions regularly arranged on the substrate (W) in accordance with the arrangement coordinates on the design is converted into a predetermined position in the stationary coordinate system defining the movement position of the substrate. In the alignment method for performing positioning with respect to the reference position, first coordinate position information regarding a coordinate position on the stationary coordinate system of at least three specific processing regions among the plurality of processing regions is detected, and By correcting each of the first coordinate position information of the at least three specific processing regions based on the flatness, and statistically calculating the corrected plurality of first coordinate position information, a plurality of the first coordinate position information on the substrate can be corrected. Calculating the second coordinate position information on the coordinate position of each of the processing regions on the stationary coordinate system, and moving the substrate according to the second coordinate position information and the flatness of the substrate. By controlling the position, it was decided to fit sequentially position each of the plurality of processing regions relative to the reference position. The 請
According to the invention as set forth in claim 25 , each of the plurality of processing regions regularly arranged on the substrate (W) in accordance with the arrangement coordinates on the design is converted into a predetermined position in the stationary coordinate system that defines the movement position of the substrate. In the alignment method for performing positioning with respect to a reference position, at least three processing regions among the plurality of processing regions are selected as specific processing regions, and a surface of the selected specific processing region and a moving plane of the substrate are aligned. A first coordinate position of each of the at least three specific processing regions on the stationary coordinate system when substantially parallel to each other;
Detecting coordinate position information;
By statistically calculating the coordinate position information, second coordinate position information on the coordinate position of each of the plurality of processing regions on the substrate on the stationary coordinate system is calculated, and the second coordinate position information and the movement of the substrate are calculated. By controlling the movement position of the substrate according to the amount of inclination of each processing region with respect to a plane, each of the plurality of processing regions is sequentially aligned with respect to the reference position. It should be noted that the above-mentioned 請
When detecting the first coordinate position information in claims 15 and 25 , the inclination amount of the surface of the substrate with respect to the moving plane of the substrate when the coordinate position of the specific processing region is measured using, for example, a surface position detection system. What is necessary is just to detect it and correct the first coordinate position information of the specific processing area using this detected value. Or, after making the moving plane of the substrate substantially parallel to the surface of the specific processing area using the surface position detection system, measure the coordinate position of the area, or process the processing area that is almost parallel to the moving plane of the substrate. What is necessary is just to select as a specific processing area, and to detect the 1st coordinate position information of this selected processing area.

According to the third and nineteenth aspects of the present invention, the weighting and the statistical operation are performed on the alignment data of the specific processing area for each processing area. That is, in each of the plurality of processing regions located on the same circle centered on the noted point, the weight given to each coordinate position of the specific processing region is naturally the same. For this reason, when a plurality of processing regions are located on the same circle centered on the point of interest, weighting and statistical calculation as described above are performed on only one of the processing regions, and the parameters (a to
By calculating f), the coordinates of the remaining processing areas can be determined using the previously calculated parameters (a to f) as they are. Therefore, when a plurality of processing regions exist on the same circle, the coordinate positions of all the processing regions on the same circle may be calculated using the same parameters (a to f). In this case, there is an advantage that the amount of calculation for determining the coordinate position is reduced.

Further, the inventions of claims 13 and 24 are effective when, for example, the substrate is partially lifted (bulged) from the holder and held. further,
The inventions of claims 15 and 25 are also effective when the substrate is partially lifted (bulged) from the holder and held.

[0022]

[0023]

According to the present invention, there is provided an alignment method capable of accurately aligning all processing regions on a substrate with a "non-linear distortion" with respect to a predetermined reference position. It is intended to provide. Therefore, what is referred to as “non-linear distortion” that is the object of the present invention for improving the alignment accuracy will be briefly described with reference to FIG. FIG. 10 is a graph showing the position measurement results (indicated by circles in FIG. 10) of a plurality of (here, four) specific processing regions (sample shots) on the substrate, and the vertical axis indicates the amount of positional deviation. The horizontal axis indicates the position from the center of the substrate. For simplicity of explanation,
It is assumed that only scaling (expansion and contraction) exists on the substrate.

In FIG. 10A, when a first-order approximation formula is created from the alignment data (coordinate position) of the sample shot using the least squares method, a straight line as shown by a solid line in the drawing is obtained. In the case of FIG. 10A, the alignment data is sufficiently approximated by a linear function (straight line), and it can be said that a linear scaling error (distortion) occurs on the substrate. The conventional EGA method employs such an approximation method. On the other hand, in FIG. 10B, since the alignment data (marked by ○) is on a smooth curve indicated by a dotted line, it can be said that “regular non-linear distortion” has occurred in the substrate. Further, in FIG. 10C, since the alignment data (marked by ○) has no regularity, it can be said that “irregular nonlinear distortion” has occurred in the substrate.

By applying the conventional EGA method as it is to FIGS. 10B and 10C and obtaining a first-order approximate expression in the same manner as in FIG. 10A, a solid line is shown in the figure. It becomes a straight line as shown. As is clear from the figure, in any case, there is a shot region with poor positioning accuracy, in other words, there is a shot region that cannot be approximated by a linear function. That is, correction of nonlinear distortion is impossible in principle with the conventional EGA method. Therefore, in the present invention, among the non-linear distortions, in particular, the “regular non-linear distortion” as shown in FIG. 10B is to be corrected, and even if the “regular non-linear distortion” occurs on the substrate, Can be accurately aligned with the reference position.

According to the first and eighteenth aspects of the present invention, the degree of weighting (parameter S in Equations 4 and 6) can be changed. , Measurement reproducibility of the alignment sensor, etc.). If the value of the parameter S is made sufficiently large, the result of the statistical operation processing becomes almost equal to the result obtained by the conventional EGA method, and if the value of the parameter S is made sufficiently close to zero, it becomes almost equal to the result obtained by the D / D method. Become. That is, in the present invention, since the parameter S can be set to an appropriate value, an intermediate effect between the EGA method and the D / D method can be obtained.

[0027]

According to the third and 19th aspects of the present invention, the substrate is effective for "regular, especially point-symmetric non-linear distortion", and is a "substrate having point-symmetric regular non-linear distortion". However, the magnitudes of the array errors at positions on the substrate at the same distance from the center of point symmetry are substantially equal. " Therefore, in the inventions according to claims 5 and 23, when determining the coordinate position of one processing area (shot area) on the substrate on the stationary coordinate system, a predetermined point of interest ( The alignment data (coordinate position) of each specific processing area is weighted according to the distance to the point of interest and the distance between the point of interest and each of the at least three specific processing areas (sample shots). In other words, the weight given to the alignment data is set greater for a specific processing area whose distance to the point of interest is closer to the distance between the point of interest and the processing area. Therefore, in the present invention, for each processing area on the substrate, a statistical operation is performed after weighting each alignment data of the specific processing area in accordance with the above two distances, and a statistical calculation is performed on the stationary coordinate system of each processing area. Will be determined. In particular, when the substrate is thermally deformed with respect to the substrate center, or when the central portion is lifted (bulged) from the holder and is attracted, the center point of the substrate, which is the point symmetric center, is set as the point of interest.

For this reason, for a substrate in which local arrangement errors (regular non-linear distortion) are point-symmetrical, for example, a substrate whose center is lifted up and held with respect to the holder , By applying the invention described in Item 19 , the coordinate positions of all the processing regions on the substrate can be accurately determined without increasing the number of sample shots. In addition, by arbitrarily selecting a weighting function and appropriately changing the degree of weighting of the alignment data, the coordinate positions of all processing regions are determined under optimum processing conditions (calculation parameters) for each substrate. It becomes possible.

Further, according to the invention of the thirteenth and twenty-fourth aspects, the present invention is effective when, for example, the substrate is partially lifted (bulged) from the holder and held.
According to the thirteenth and twenty-fourth aspects , when an arbitrary portion of the substrate is lifted from the holder and adsorbed, each of the coordinate positions on the stationary coordinate system of at least three specific processing regions is corrected based on the flatness of the substrate (coordinates). Conversion) and statistically calculating the corrected plurality of coordinate positions, thereby calculating the coordinate positions on the stationary coordinate system of each of the plurality of substrates to be processed on the substrate. In aligning each of the plurality of processing regions with the reference position, the previously calculated coordinate position and the flatness of the substrate are used, that is, the calculated coordinate position is corrected again based on the flatness of the substrate ( The position of the substrate is controlled in accordance with the corrected coordinate position. For this reason, even if an arbitrary portion of the substrate has a bulge, the coordinate positions of all the processing regions on the substrate can be accurately determined, and the alignment accuracy can be improved without increasing the number of sample shots. Becomes

Further, similarly to the invention also the claims 13 and 24 according to claim 15, 25, the substrate is lifted from the partially holder (inflated at) is effective if it is maintained. According to the fifteenth and twenty-fifth aspects, the coordinate position of each of at least three specific processing regions when the surface of the specific processing region and the moving plane of the substrate are substantially parallel is detected, for example, using a surface position detection system. After making the moving plane of the substrate substantially parallel to the surface of the specific processing area, the coordinate position of the area is detected. Further, by statistically calculating the detected plurality of coordinate positions, the coordinate positions of each of the plurality of processing regions on the substrate on the stationary coordinate system are calculated. In aligning each of the plurality of processing regions with the reference position, the previously calculated coordinate position and the amount of tilt for each processing region with respect to the moving plane of the substrate are used, that is, the amount of tilt detected for each processing region. The coordinate position is corrected on the basis of the coordinates, and the movement position of the substrate is controlled according to the corrected coordinate position. For this reason, even if an arbitrary portion of the substrate has a bulge, the coordinate positions of all the processing regions on the substrate can be accurately determined, and the alignment accuracy can be improved without increasing the number of sample shots. Becomes

[0032]

FIG. 2 is a diagram showing a schematic configuration of a projection exposure apparatus suitable for applying the alignment method according to the present invention, and FIG. 3 is a block diagram of a control system of the projection exposure apparatus shown in FIG. is there. In FIG. 2, illumination light IL (i-line, KrF excimer laser, or the like) from an exposure illumination system (not shown) passes through a condenser lens CL through a pattern area P of a reticle R.
A is illuminated with uniform illuminance. The illumination light IL that has passed through the pattern area PA is projected on both sides by a telecentric projection optical system P.
L, the projection optical system PL forms and projects an image of the circuit pattern formed in the pattern area PA onto a wafer W having a resist layer formed on the surface. The wafer W is mounted on a Z stage LS via a wafer holder (not shown), and the Z stage LS is
It is configured to be finely movable in the optical axis AX direction (Z direction) of L and tiltable in any direction. Z stage LS
X, Y by step and repeat method by motor 12
It is mounted on a wafer stage WS that can move two-dimensionally in the direction. The position of the wafer stage WS in the X and Y directions is always detected by the laser interferometer 15 with a resolution of, for example, about 0.01 μm. A movable mirror 14 that reflects the laser beam from the interferometer 15 is fixed to an end of the Z stage LS. It is desirable that the movable mirror 14 be, for example, a corner cube.

In FIG. 2, a TTL laser step alignment (LSA) system 17 for detecting an alignment mark on the wafer W is provided. LS
As shown in FIG. 11A, the A-system 17 irradiates an elongated band-shaped spot light LXS to an alignment mark (diffraction grating mark) Mx attached to each shot area on the wafer via the projection optical system PL. Are subjected to photoelectric detection of diffracted light (or scattered light) generated from the mark Mx when the relative scanning is performed. Since the configuration of the LSA system 17 is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-130742, a detailed description is omitted here. Further, in FIG. 2, L for detecting the position of the alignment mark in the Y direction is used.
Although only the SA system is shown, another set of LSA systems for detecting the position in the X direction is actually arranged. LSA system 17
Are input to the alignment signal processing circuit 16 together with the position signal from the interferometer 15, where the position of the alignment mark is detected, and this position information is output to the main controller 10.

FIG. 2 shows, for example, Japanese Patent Application Laid-Open No. 2-54.
Off-axis type alignment sensor (hereinafter referred to as Field Image Alignment
t (FIA) system) 20 is also provided. The FIA system 20 includes illumination light (for example, white light) having a predetermined wavelength width.
12A, an image of the alignment mark (WM ₁ ) on the wafer as shown in FIG. 12A and an index mark (FM ₁ , FM ₁ , The image of FM ₂ ) is formed on a light receiving surface of an image pickup device (such as a CCD camera) and detected. FIA
The image signal from the system 20 is also sent to the alignment signal
, Where the position of the alignment mark is detected, and this position information is output to main controller 10.

The main control unit 10 includes a processing circuit 1 as described later.
6, the EGA calculation is performed based on the position information, and the coordinate positions of all shot areas on the wafer W (shot arrangement)
Is calculated, and overall control of the entire apparatus is performed. The stage controller 11 follows a drive command from the main control device 10,
Based on various information from the interferometer 15 and the surface position detection systems 18 and 19, the wafer stage W
The drive of the S and Z stages LS is controlled. FIG. 2 also shows oblique incident light type surface position detection systems 18 and 19. The surface position detection systems 18 and 19 are for detecting the height position (position in the Z direction) of the wafer surface and the inclination angle thereof.
The description is omitted here since it is disclosed in Japanese Patent Application Laid-Open No. 13706.

Next, a specific configuration of main controller 10 will be described with reference to FIG. In FIG. 3, an alignment signal processing circuit 16 receives a photoelectric signal from the LSA system 17 (or an image signal from the FIA system 20) and a position signal from the interferometer 15, and is attached to each shot area by predetermined signal processing. The detected position of the alignment mark (that is, the coordinate value in the orthogonal coordinate system XY defined by the interferometer 15) is detected. Alignment data storage unit 10
Reference numeral 5 indicates that mark position information from the alignment signal processing circuit 16 can be input. The EGA calculation unit 100
A plurality (3 or more, usually 1) stored in the storage unit 105
Shot area (sample shot) of about 0 to 15)
The coordinate positions of all shot areas on the wafer W are calculated by statistical calculation based on the respective mark position information and the weighting function determined by the weight generation unit 101. The storage unit 106 can input the shot array, calculation parameters, and the like calculated by the EGA calculation unit 100.

The exposure shot position data section 102 stores design array coordinate values of shot areas to be exposed on the wafer W, and these coordinate values are stored in the EGA calculation section 100, the weight generation section 101, and the sample shot designation section. It is output to 103. The sample shot specifying unit 103 includes the data unit 10
The sample shots used for the EGA calculation are determined based on the shot position information from No. 2 and the information (number and position) on the arrangement of the sample shots is determined by the weight generation unit 10.
1 and the sequence controller 104. The weight generation unit 101 determines a weighting function based on the shot position information from the position data unit 102 and the information on the arrangement of the sample shots from the designation unit 103, and provides this function to the EGA calculation unit 100. The sequence controller 104 determines a series of procedures for controlling the movement of the wafer stage WS at the time of alignment or step-and-repeat exposure based on the various data, and controls the entire apparatus.

Next, an alignment method according to the first embodiment of the present invention will be described with reference to FIG. The positioning method of the present embodiment is based on the conventional EGA method, and when determining the coordinate position of the i-th shot area ESi on the wafer W, m (9 = 9 in FIG. 1) the area ESi. Distance L _K1 between each of shots SA _{1 to} SA ₉
Depending on the L _K9, it is characterized by providing a weighting W _in each of the nine sample shots alignment data (coordinate position). Therefore, in this embodiment, two sets of LSA
After detecting the alignment marks (Mx ₁ , My ₂ ) of each sample shot using the system, the sum of squares Ei of the residual is evaluated by the following equation (Equation 3) in the same manner as in the above Equation 2, and the following equation is minimized. The calculation parameters a to f may be determined so that
In this embodiment, the sample shots (alignment data) used for each shot area are the same, but since the distance to each sample shot is different for each shot area, the alignment data (coordinate position of the sample shot) is used. weighting W _in giving to will change for each shot region. Therefore, by determining the parameters a to f for each shot area and calculating their coordinate positions, the coordinate positions (shot arrangement) of all the shot areas are determined.

[0039]

(Equation 3)

[0040] Here, for each shot area on the wafer W in the present embodiment, changing the weighting W _in for each sample shot alignment data. Therefore, the weight W _in the following equation, as a function of the distance L _kn the i th shot area ESi and n-th sample shot SA _n. Here, S is a parameter for changing the degree of weighting.

[0041]

(Equation 4)

[0042] As is clear from Equation 4, the distance L _kn to i-th shot area ESi is shorter sample shots, so that the weight W _in giving to the alignment data (coordinate position) increases . Here, when the value of the parameter S in Expression 4 is sufficiently large, the result of the statistical calculation processing is almost equal to the result obtained by the conventional EGA method. On the other hand, all shot areas to be exposed on the wafer are sample shots, and the parameter S
Is sufficiently close to zero, the result is almost equal to the result obtained by the D / D method. That is, in this embodiment, by setting the parameter S to an appropriate value, the EGA method and the D
An intermediate effect of the / D system can be obtained.

For example, for a wafer having a large non-linear component, the value of D / D
An effect (alignment accuracy) almost equivalent to that of the D method can be obtained. That is, in the positioning method (EGA calculation) according to the present embodiment, it is possible to satisfactorily remove alignment errors due to nonlinear components. When the measurement reproducibility of the alignment sensor is poor, by setting a large value of the parameter S, it is possible to obtain an effect almost equivalent to that of the EGA method, and it is possible to reduce an alignment error by an averaging effect. Becomes

[0044] Furthermore, the above-mentioned weighting function (Equation 4) are each are prepared in the X-direction alignment marks (Mx _1, etc.) and the Y-direction alignment mark (My _1, etc.), X-direction and Y it is possible to independently set the weighting W _in with the direction. For this reason, the degree (large or small) and regularity of the nonlinear distortion of the wafer, or the step pitch, that is, the distance between the centers of two adjacent shot areas (depending on the width of the street line on the wafer, almost corresponds to the shot size) Even if the values obtained in the X direction and the Y direction are different, the shot arrangement error on the wafer can be accurately corrected by independently setting the value of the parameter S. Here, the value of the parameter S may be different between the X direction and the Y direction as described above, and even if the value of the parameter S in the X and Y directions is the same or different, The value of S may be appropriately changed according to the magnitude and regularity of the “regular nonlinear distortion”, the step pitch, the measurement reproducibility of the alignment sensor, and the like.

As described above, by appropriately changing the value of the parameter S, the effect can be changed from the EGA system to the D / D system. Therefore, alignment is performed on various layers and further on each component (X direction and Y direction) according to, for example, characteristics of nonlinear components (for example, magnitude, regularity, etc.), step pitch, and measurement reproducibility of the alignment sensor. It is possible to flexibly change the alignment and to perform alignment under optimum conditions for each layer and each component.

In this embodiment, the arrangement (number, position) of the sample shots is not described. However, the preferred arrangement in this embodiment is to draw the sample shots around the wafer as in a conventional EGA system. Instead, the sample shots may be set evenly over the entire surface of the wafer as shown in FIG. 9A, for example. In particular, to increase the density of sample shots around the wafer,
As shown in FIG. 9B, a large number of sample shots may be set in a donut-shaped (ring-shaped) area. In FIG. 9B, a plurality of sample shots are naturally set inside the donut-shaped region. In the present embodiment, it is preferable to select a shot area in a partial area where the amount of displacement (that is, the amount of nonlinear distortion) on the wafer is large as a sample shot. It is better to set more than the area.

Next, an alignment method according to a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, a regular, particularly point-symmetric, non-linear distortion is generated in the wafer W. More specifically, as shown in FIG. 5, the wafer W is swelled with respect to its center Wc and held by the holder. The following describes a suitable alignment method. FIG. 6 is a vector map showing the shift amount of each shot area on the wafer having the nonlinear distortion shown in FIG. 5 from the ideal lattice.

As in the first embodiment, the present embodiment is based on the conventional EGA system, and the center of deformation of the wafer (the center of non-linear distortion point symmetry), which is the point of interest on the wafer, that is, the wafer center Wc, The distance (radius) L _Ei between the i-th shot area ESi on the wafer W and the wafer center Wc and m (m = 9 in FIG. 4) sample shots S
Depending on the distance (radius) L _W1 ~L _W9 between each of A ₁ -SA _9, it is characterized by providing a weighting W _in 'to each of the nine sample shots alignment data. Therefore, in this embodiment, the two sets of alignment marks (Mx ₁ , Mx ₁₎ are used for each sample shot using the LSA system.
After detecting y ₁ ), the sum of squares of the residual Ei ′ is evaluated by the following equation (Equation 5), and the calculation parameters a to f are determined so as to minimize the following equation. good. Similar to the well first embodiment in the present embodiment, the weighting W _in providing the alignment data 'to vary from shot area,
A statistical operation is performed for each shot area to determine the parameters a to f, and their coordinate positions are determined.

[0049]

(Equation 5)

Here, for each shot area on the wafer W,
'For changing the weighting W _in the following equation' weighting W _in for each sample shot it is expressed as a function of the distance (radius) L _Ei of the i-th shot area ESi and wafer center Wc of the wafer W. Here, S is a parameter for changing the degree of weighting.

[0051]

(Equation 6)

As is apparent from Equation 6, the distance (radius) L _Wn to the wafer center Wc is different from the wafer center Wc.
as sample shot closer to the distance (radius) L _Ei between the i-th shot area ESi on c and the wafer W, so that the weight W _in 'giving to the alignment data is increased. In other words, the largest weighting W _in respect to the sample shots alignment data located on a circle with a radius L _Ei around the wafer center Wc '
And giving, so as to reduce the weight W _in 'with respect to the alignment data in accordance with radially away from the yen.

The value of the parameter S in the equation (6) is the same as the alignment accuracy required in the first embodiment.
What is necessary is just to determine suitably according to the characteristic (for example, magnitude, regularity, etc.) of a nonlinear distortion, a step pitch, the quality of measurement reproducibility of an alignment sensor, etc. That is, when the nonlinear component is relatively large, by setting the value of the parameter S to be smaller, it is possible to reduce the influence of the sample shot in which the distance L _Wn from the wafer center Wc is largely different.
On the other hand, when the nonlinear component is relatively small, by setting the value of the parameter S to a larger value, it is possible to prevent a decrease in alignment accuracy in an alignment sensor (or layer) having poor measurement reproducibility.

Further, in this embodiment, weighting is performed on the alignment data of the sample shots for each shot area, and statistical calculation (ie, calculation of parameters a to f).
To do. However, in each of a plurality of shot areas at substantially the same distance from a point of interest (center of point symmetry) on the wafer, that is, a plurality of shot areas located on the same circle centered on the point of interest, the sample shot weighting W _in 'is the same to be given to the alignment data. For this reason, when a plurality of shot areas are located on the same circle centered on the point of interest, weighting and statistical calculation as described above are performed on only one of the shot areas to set the parameters a to f. With the calculation, the coordinates of the remaining shot areas can be determined using the previously calculated parameters a to f as they are. Therefore, when a plurality of shot areas exist on the same circle, the same parameters a to
The coordinate positions of all shot areas on the same circle may be determined using f. In this case, there is an advantage that the amount of calculation for determining the coordinate position is reduced.

By the way, in the arrangement of the sample shots suitable for the alignment method according to the present embodiment, it is desirable to designate the shot area so as to be symmetric with respect to the point symmetric center of the nonlinear distortion, that is, the wafer center Wc. What is necessary is just to select into the X-shape, cross shape, etc. used as a reference. Alternatively, the arrangement may be the same as that of the first embodiment (FIG. 9). If the point symmetry center of the non-linear distortion is other than the wafer center, the X-shaped or cross-shaped arrangement based on the point symmetry center may be used. Also, in this embodiment, when determining the parameters a to f, the weighting function shown in Expression 5 may be set independently in each of the X and Y directions, as in the first embodiment.
In this case, even if the magnitude, regularity, step pitch, and the like of the nonlinear distortion are different between the X direction and the Y direction, the parameter S
Is set independently, an advantage is obtained that the shot arrangement on the wafer can be calculated with high accuracy.

Further, when S = 120 in Equation 6 above and the alignment method according to the present embodiment is applied to the wafer shown in FIG. 5, the alignment accuracy is X + 3σ = 0.
09 μm. On the other hand, when the alignment of the sample shots was the same as that described above and the alignment was performed by the conventional EGA method, the alignment error was X + 3σ = 0.21.
μm, and it was confirmed that the alignment accuracy was clearly improved as compared with the conventional method.

In the first and second embodiments, equations (4) and (6) are used.
Weighting W _in, W _in 'shown in, it is determined by the weight generating unit 101 based on the arrangement of sample shots. Further, in the alignment methods of the first and second embodiments, the degree of weighting of the alignment data of the sample shot can be changed by the parameter S as described above. Hereinafter, a method of determining the parameter S in the weight generation unit 101 will be described. Equation 7 below is stored in the weight generation unit 101. For example, when the operator sets the weight parameter D to a predetermined value, the parameter S,
That is, the weighting W _in, or W _in 'is determined.

[0058]

(Equation 7)

Here, the physical meaning of the weight parameter D is the range of sample shots (hereinafter simply referred to as zones) effective for calculating the coordinate position of each shot area on the wafer. Therefore, when the zone is large, the number of effective sample shots increases, and the result is close to the result obtained by the conventional EGA method. Conversely, if the zone is small, the number of valid sample shots will be small, so D
/ D approach. However, the range (zone) mentioned here is only a reference value for weighting, and even if all the sample shots exist outside the zone, the coordinate position is determined in the same manner as in the above embodiment. The statistical calculation is performed by maximizing the weight for the alignment data of the sample shot closest to the shot area to be determined.

FIG. 7 shows that the weight parameter D is 30, 60,
This is a visual representation of the size of the zone at 90 and 120 [mm]. However, as shown in FIG. 8, the weight parameter, that is, the diameter D of the zone is “0.1 when the weight of one shot area whose coordinate position on the wafer is to be determined is 1”. The diameter (unit: mm) of the area (sampling zone) ". In addition, it has been confirmed that the optimum value of the diameter D generally exists between 30 and 150 [mm].

Therefore, in the above embodiment, the operator inputs the optimum zone diameter D determined based on the operator's experience or by experiment or simulation to the main controller 10 via an input device (keyboard or the like). Equation 7 shows the degree of weighting of the alignment data, that is, weights Win and W _in Equations 4 and 6.
_in 'will be determined. For this reason, the alignment of various layers can be flexibly changed according to, for example, the magnitude of the non-linear component, the quality of measurement reproducibility of the alignment sensor, and the like, and alignment can be performed under optimum conditions for each layer. .

By the way, in addition to the operator directly inputting the optimum zone diameter D to the main controller 10, for example, among the plurality of wafers stored in a lot, the first (first) wafer may be used. In contrast, mark detection is performed for almost all shot areas. Then, main controller 10 calculates the regularity and degree (size) of the nonlinear distortion of the wafer based on the detection result, and then calculates the optimal zone diameter D (in the second embodiment, the distortion center of the nonlinear distortion is further increased). May be determined). As a result, without the operator at all intervening automatically weighting function W _in equations 4, 6, W _in 'is determined, for second and subsequent wafers original in such a position of the foregoing of the weighting function A matching operation will be performed.

The first wafer may be aligned using the previous mark detection result, or may be calculated by calculating the shot array using the weighting function determined as described above. You may do it. Further, here, the mark detection (coordinate position measurement) of almost all shot areas is performed only for the first wafer, but the mark detection of almost all shot areas is performed for the first to several wafers. to perform the weighting to calculate the regularity and size of the non-linear distortion using the averaging processing or the like W _in, may be determined for W _in '. Further, the regularity and magnitude of the non-linear distortion calculated by the main control device 10 are displayed on a display device (CRT or the like) as a vector map as shown in FIG. 6, for example, and an operator is displayed based on the displayed map. May determine the optimal zone diameter D and input it to the main controller 10.

Here, in the above description, the operator inputs the value of the diameter D of the optimum zone to the main controller 10. However, for example, a wafer or a lot (loader cassette) for storing a plurality of wafers is used. The above value is described in the form of an identification code (a bar code or the like), and the code is read by a reading device (a bar code reader or the like).
May be determined. Also, the weight generation unit 101
Is not limited to Expression 7, and the following Expression 8 may be used.
Here, A is the area of the wafer (the unit is mm ² ), m is the number of sample shots, and C is a correction coefficient (positive real number).

[0065]

(Equation 8)

Equation 8 reflects the change in the wafer size (area) and the number of sample shots in the determination of the parameter S so that the optimum value of the correction coefficient C to be used in the determination does not change much. It is. Here, when the correction coefficient C is small, the value of the parameter S is large, so that the result is close to the result obtained by the conventional EGA method, just like the case of Expression 7. Conversely, when the correction coefficient C is large, the value of the parameter S is small, so that the result is close to the result obtained by the D / D method as in the case of Expression 7. Therefore, by simply inputting the correction coefficient C determined in advance by an experiment or a simulation to the main controller 10 via an operator or an identification code reader, the degree of weighting for the alignment data can be calculated from Equation 8 as follows:
That is, the weighting W _in formulas 4, 6, W _in 'is automatically determined. For this reason, alignment is performed on various layers and further on each component (X direction and Y direction) according to, for example, characteristics of nonlinear components (for example, large and small, regularity, etc.), step pitch, and measurement reproducibility of the alignment sensor. Can be flexibly changed, and alignment can be performed under optimum conditions for each layer and each component. In particular, when Expression 8 is used, even if the wafer size, the step pitch (shot size), the number of sample shots, and the like change, the coordinate positions of all shot areas on the wafer can be accurately determined regardless of the change, and are always stable. There is also an advantage that the alignment can be performed with a given accuracy.

In each of the above embodiments, m sample shots are selected from a plurality of shot areas on a wafer, and weighting is performed on each alignment data of the selected sample shots. Shall be performed. At this time, if any of the two sets of alignment marks cannot be measured, or if there is a sample shot whose measurement value is suspicious (low reliability), a shot area near the shot is designated as a substitute shot, and this designation is made. The alignment data of the alternative shot may be used. Alternatively, sample shots that cannot be measured or have low reliability may be rejected, or the weight given to the alignment data may be set to zero, and only the alignment data of the remaining sample shots may be used. Furthermore, if only one of the two sets of alignment marks (for example, the X mark) cannot be measured, or if the measured value of the sample shot has low reliability,
Only the coordinate position of the other alignment mark (Y mark) is used. Alternatively, an X mark in a shot area near the shot may be detected and its coordinate position may be used.

By the way, there is a case where the alignment accuracy is not improved even if the alignment method of each of the above embodiments is applied. This is because in the above embodiments, among the nonlinear distortions, particularly regular ones are used. This is because they are to be corrected. Therefore, when the alignment accuracy is not improved as described above, it is considered that the wafer has many irregular nonlinear components. Usually, it is difficult to improve the alignment accuracy by applying any of the alignment methods to a wafer having an irregular nonlinear distortion, but here, the wafer has an irregular nonlinear distortion, that is, the alignment accuracy is not improved. Let us consider the case where the measurement reproducibility of the alignment sensor is good and the case where the measurement reproducibility of the alignment sensor is bad.

If the measurement reproducibility of the alignment sensor is poor, a result is obtained as if the wafer had irregular nonlinear distortion even though the wafer itself did not have irregular nonlinear distortion. Sometimes.
In such a case, an alignment sensor and / or a signal processing condition that can obtain good measurement reproducibility for the wafer may be selected and used. More specifically, when the alignment mark on the wafer has a low step, for example, Japanese Patent Application Laid-Open Nos.
As disclosed in JP-A-272406, a one-dimensional interference fringe is formed by irradiating a one-dimensional diffraction grating mark on a wafer with a coherent parallel beam from two directions.
An alignment sensor (hereinafter referred to as “Lase”) that photoelectrically detects interference light of diffracted light generated from the mark in almost the same direction.
r Interferometric Alignment (LIA) system) may be used. When a metal layer is formed on the wafer surface, the FIA system 20 in FIG. 2 may be used.

Also, without changing the alignment sensor,
Only the signal processing condition of the sensor may be changed so as to correspond. The signal processing conditions in the LSA system indicate a waveform analysis algorithm, an algorithm slice level, a processing gate width, and the like. Note that the processing gate width is determined around a design mark position. Also,
As the waveform analysis algorithm, for example, the following 3
There are two algorithms.

In the first algorithm, after smoothing the signal waveform in the section determined by the predetermined processing gate width, this signal waveform is sliced at the level set by the algorithm slice level, and FIG. As shown, when there are intersections on the left and right of the signal waveform, the center point of the two intersections is detected as a mark position. In the second algorithm, after performing a smoothing of the signal waveform in a section equal to or higher than a predetermined level L ₁ (voltage value), a plurality of slice levels are set at regular intervals with a level L ₂ close to a peak value, Find the intersection at each slice level and its length. Then, based on the length at each slice level, a slice level at which the slope of the signal waveform is maximum in a portion below the level set at the algorithm slice level is selected, and the center point of the intersection at the level is set as a mark position. It is to detect. In the third algorithm, a signal waveform is sliced at a level set at an algorithm slice level, and a center point thereof is obtained as a reference position. Next, after smoothing the signal waveform in a section equal to or higher than a predetermined level L ₁ (voltage value), a plurality of slice levels are set at regular intervals between the signal level and a level L ₂ close to the peak value. , The center point of the two intersections, and the midpoint difference (that is, the difference from the center point at the adjacent slice level) is obtained. Then, a region where the center point at each slice level is not far away from the previously obtained reference position and each center point is stable (that is, the midpoint difference is minute,
The region where the slice level is the longest and continuous) is selected, and the center point in the region is detected as a mark position.

Further, referring to FIG. 12 and FIG.
The signal processing conditions in each of the LIA system and the LIA system will be briefly described. Figure 12 (A) shows a state of the wafer mark WM ₁ detected by the FIA system, and FIG. 12 (B) is shown the waveform of the image signal obtained at that time. As shown in FIG. 12A, the FIA system 20 (imaging element) has a wafer mark WM.
_{The image} of the three bar marks and the index marks FM ₁ and FM ₂ is electrically scanned along the scanning line VL. At this time, 1
Since the number of scanning lines alone is disadvantageous in terms of the S / N ratio, the levels of image signals obtained by a plurality of horizontal scanning lines entering the video sampling area VSA (dot-and-dash line) are averaged for each pixel in the horizontal direction. good. As shown in FIG. 12B, the image signal has index marks FM ₁ and FM _{2 on} both sides.
Each has a waveform portion corresponding to, the alignment signal processing section 16 obtains the center position of each mark (position of the pixel) by processing the waveform portion by the slice level SL _2, obtains the center position x ₀ ing. Instead of obtaining the respective center positions of the index mark FM _1, FM _2, by obtaining the respective positions of the right edge and the left edge of the index mark FM ₂ of the index mark FM _1, so as to obtain the center position x ₀ No problem. On the other hand, here, as shown in FIG. 12 (B), the waveform on the image signal has a bottom at a position corresponding to the left edge and the right edge of each bar mark, and the signal processing unit 16 determines the slice level SL ₁ after performing waveform processing obtains the center position of each bar marks, calculates the center position x _C of the wafer mark WM ₁ by averaging the positions. Further, the difference Δ between the previously obtained position x ₀ and the mark measurement position x _C
x (= x ₀ −x _C ) is calculated, and a value obtained by adding the difference Δx from the position of the wafer stage WS when the wafer mark WM ₁ is positioned in the observation area of the FIA system 20 to the mark position information Output as

Therefore, the signal processing conditions that can be changed in the FIA system 20 as described above include a waveform analysis algorithm, a slice level SL ₁ (voltage value), a contrast limit value, and a processing gate width Gx (width Gx on a pixel) Center position and its width). Further, as a waveform analysis algorithm, for example, as disclosed in Japanese Patent Laid-Open No. 4-65603, when determining the center position of each bar mark, waveform portions BS _1L , BS _1L , BS _{1 1R} , BS _2L and BS _2R
Outer slope BS _1L, mode using only BS _2R, inner slope BS _1R, mode using only BS _2L, the outer slope BS _1L, BS _2R, and an inner slope BS _1R, there is a mode using a BS _2L.

Next, signal processing conditions in the LIA system (particularly, the heterodyne system) will be described with reference to FIG.
As shown in FIG. 13, for one-dimensional diffraction grating mark WM ₂ on the wafer, the coherent beam (parallel beam) BM ₁ 2 pieces of the frequency difference Delta] f, BM ₂ is incident at an intersection angle (2ψ ₀₎ , the pitch P (except for on the mark WM _2,
One-dimensional interference fringes IF having a grating pitch 2P) are created. The interference fringes IF is moved in response to the frequency difference Delta] f in the pitch direction of the diffraction grating mark WM _2, the velocity V is V = Delta] f
Is represented by the relational expression P. As a result, diffraction light B ₁ (-1) and B ₂ from the diffraction grating mark WM ₂ as shown in FIG.
(+1),... Occur. The subscripts 1 and ₂ indicate the correspondence with the incident beams BM ₁ and BM _2, and the numbers in parentheses indicate the diffraction orders. Normally, in the LIA system, a reference signal separately generated from the photoelectric signal of the interference light of ± 1st-order diffracted light B ₁ (-1) and B ₂ (+1) traveling along the optical axis AX, and two transmitted light beams The position shift is detected by obtaining the phase difference between the interference signal and the photoelectric signal. Or, the 0th order diffracted light B ₂ (0) and −
The amount of displacement detected from the phase difference between the photoelectric signal of the interference light with the second-order diffracted light B ₁ (-2) and the photoelectric signal for reference, the 0-order diffracted light B ₁ (0) and the -2nd-order diffracted light B ₂ ( The position shift amount may be obtained by adding and averaging the position shift amount detected from the phase difference between the photoelectric signal of the interference light with (+2) and the reference photoelectric signal.

Accordingly, the only signal processing condition that can be changed in the LIA system as described above is the selection of interference light (order of diffracted light) to be photoelectrically detected. That is, in the LIA system, the first mode using ± 1st-order diffracted lights B ₁ (−1) and B ₂ (+1), the 0th-order diffracted light B ₂ (0) and the −2nd-order diffracted light B ₁ (-2), and 0 A second mode using the second-order diffracted light B ₁ (0) and the _second-order diffracted light B ₂ (+2),
Further, there is a third mode in which the intensity of the interference light in the first mode and the intensity of the interference light in the second mode are compared with each other and the one having the larger intensity value is selected and used.
The simulation is performed by changing the two modes.

As described above, when the measurement reproducibility of the alignment sensor is poor, by changing the alignment sensor and the signal processing conditions, the mark detection is performed under the optimum conditions for the layer. Just do it. Also,
When the alignment sensor and the signal processing conditions are not changed, measurement may be performed a plurality of times for one alignment mark.

On the other hand, when the measurement reproducibility of the alignment sensor is good, the case where the measured value is reliable and the case where the measured value is not reliable can be considered. When the reliability of the alignment data of the sample shot is high and irregular nonlinear distortion exists in the alignment data, it is considered that the wafer actually has irregular nonlinear distortion. In such a case, it is preferable to increase the number of sample shots, reduce the diameter D of the zone in Equation 7, or increase the correction coefficient C in Equation 8. If the alignment accuracy is not improved even after optimizing the parameter S and the arrangement (number and position) of the sample shots, the alignment sensor cannot accurately measure the mark position due to the influence of coverage or the like. It is considered low. In such a case, FIA that is not easily affected by coverage etc.
It is preferable to perform the alignment using the system 20.

The case where the wafer is considered to have irregular non-linear distortion has been described above. For a wafer having regular non-linear distortion, the parameter S (that is, the zone diameter D and the correction coefficient C), By changing at least one of the number of sample shots, the arrangement (position), the alignment sensor, and the signal processing conditions of the alignment sensor, alignment is performed under optimal conditions for each layer. good. In other words,
After selecting the optimal alignment sensor and signal processing conditions for the layer, it is desirable to optimize the parameters S, the number of sample shots, and the arrangement conditions.

In the EGA method, with respect to the regularity of the arrangement of shot areas on one wafer, the wafer scaling amounts Rx, Ry in the X and Y directions, the offset amounts Ox, Oy, The residual rotation error θ of the array coordinate system of the shot area and the amount of inclination (orthogonality) ω of the array coordinate system are introduced as variable elements. That is, these six elements are represented by the following parameters by the operation parameters a to f.

Rx = a Ry = d Ox = e Oy = f θ = c / d ω = − (b / a + c / d) Therefore, the first and second embodiments are applied to a single wafer. In determining the coordinate position of each shot area, two types of alignment sensors, for example, an LSA system and an FIA system are used. That is, the coordinate positions of all sample shots are measured using each of the LSA system and the FIA system,
Furthermore, after calculating the operation parameters a to f using the least square method, the coordinate position of one shot area is determined using the two sets of operation parameters a to f. Specifically, L
The above six variable elements are determined from the calculation parameters a to f calculated from the measurement results of the SA system, and the above six variable elements, especially scaling parameters Rx and Ry are calculated from the calculation parameters a to f calculated from the measurement results of the FIA system. To determine. Then, after replacing the scaling parameter of the LSA system with the scaling parameter of the FIA system, the operation parameter is calculated using the scaling parameters Rx, Ry and the remaining four variable elements (Ox, Oy, θ, ω) of the LSA system. a to f are determined, and the coordinate position of one shot area is calculated based on the parameters. As described above, by determining the calculation parameters a to f by using two types of alignment sensors properly, it becomes possible to improve the calculation accuracy of the coordinate position of the shot area as compared with the previous embodiments. However, the arrangement (number, position) of the sample shots in the LSA system and the FIA system is exactly the same. The degree of weighting (the value of the parameter S) is also the same. Although the LSA system and the FIA system are used here, the number of alignment sensors to be used,
Any combination may be used.

In the above description, L is set for each shot area.
Each of the SA system and the FIA system detects a mark of a sample shot and calculates a calculation parameter by the least square method. Here, when determining the coordinate position of one shot area on the wafer, if the difference between the calculation parameters calculated for each of the LSA system and the FIA system is large, the LSA
It is considered that the measurement error of one of the system and the FIA system is large, and it may be difficult to accurately calculate the coordinate position of the shot. Therefore, main controller 10 informs the operator of the state by an alarm, a screen display, or the like, or automatically performs re-measurement when the difference exceeds a predetermined allowable value. When remeasurement is performed, the type and combination of alignment sensors may be changed, a new alignment sensor may be added, and the like. Also,
If the difference is equal to or less than the allowable value, the parameters a to f determined after replacing some of the variable elements as described above, or one of the two sets of calculation parameters, or the average value thereof are used. What is necessary is just to determine the coordinate position of the shot area.

After measuring the coordinate positions of all sample shots using one type of alignment sensor, for example, FIA system, the degree of weighting (value of parameter S)
Are determined using each of two sets of weighting functions (Equation 4 or 6). At this time, the values of the two parameters S are set, for example, to a value at which a result almost equivalent to the EGA method is obtained and a value at which a result almost equivalent to the D / D method is obtained. When determining the coordinate position of the shot area using the two sets of calculation parameters calculated under the two sets of weighting functions, the calculation parameters determined under the EGA-like weighting function, ie, six Of the variable elements, the offset amounts Ox and Oy are used, and as for the remaining four variable elements, variable elements determined from operation parameters determined based on a D / D weighting function are used. Further, an operation parameter may be determined from these six variable elements, and the coordinate position may be determined using the parameter. Note that the two parameters S may have any values, and may be appropriately determined according to the type of layer, the characteristics of nonlinear distortion, and the like.

Next, an alignment method according to a third embodiment of the present invention will be described. Here, a preferred alignment method for the wafer W having the regular nonlinear distortion shown in FIG. 5 will be described. In the present embodiment, weighting is not performed for each sample shot as in the second embodiment. The method is characterized in that the swelling of the wafer is obtained by using, for example, the surface position detection systems 18 and 19 using the flatness (flatness) of the wafer surface, and the alignment is performed using this.

The pitches Px, Px in the X and Y directions
When a measurement point (for example, an alignment mark) is provided at y, and the height h (i, j) at an arbitrary position (i, j) on the wafer is measured, the X and Y directions at the position (i, j) are obtained. IncX, IncY (for example, the inclination with respect to the moving plane of the wafer, that is, the orthogonal coordinate system XY defined by the interferometer)
Is represented by the following equation.

[0085]

(Equation 9)

FIG. 14 is an enlarged view of a part of the cross section (part of the bulged portion) of the wafer having a partially bulged portion. Assuming that no displacement occurs in the central portion, the displacement amounts (lateral displacement amounts) ΔSx and ΔSy in the X and Y directions at the position (i, j) are expressed by the following equations.

[0087]

(Equation 10)

Therefore, the wafer (ie, shot area)
It is possible to determine the nonlinear distortion due to the bulging (warping) of the wafer based on the flatness (flatness) and the thickness t of the wafer. In addition, each inclination IncX in the X and Y directions at the position (i, j) using the surface position detection systems 18 and 19,
IncY is measured directly, and the result is used as ΔSx, ΔS
y may be obtained from Expression 10.

Next, the positioning operation of this embodiment will be described. In this embodiment, it is assumed that the wafer center is the highest swelling, and the flatness of the wafer, for example, the difference between the height of each shot area on the wafer and the wafer center is measured by using the surface position detection systems 18 and 19, and this data is obtained. Is stored in the storage unit 106. Also,
The storage unit 106 also stores information on the thickness t of the wafer. Here, the surface position detection systems 18 and 19 are, for example, a moving coordinate system (orthogonal coordinate system XY) of the wafer stage WS.
It is assumed that the calibration has been performed in advance so that the plane including is used as the zero point reference. Note that the alignment method according to the present embodiment can use the apparatus shown in FIGS. 2 and 3 as it is. However, in this embodiment, there is no need to perform weighting in the EGA calculation, so that the weight generation unit 101 becomes unnecessary.

In this embodiment, in the apparatus shown in FIGS. 2 and 3, each coordinate position of a plurality of sample shots selected in advance is measured by the LSA system 17, and the measured values are used to obtain the equation (9). , The lateral shift amounts ΔSx and ΔSy in each sample shot are calculated.
The coordinate position of each sample shot is corrected using x and ΔSy. That is, the coordinate position of each sample shot in a state where the apparent wafer is almost flatly sucked by the holder is obtained. Thereafter, using the corrected plurality of coordinate positions, a conventional EGA calculation (formulas 1 and 2) is performed to calculate the coordinate positions (first shot arrangement) of all shot areas on the wafer. Next, using the calculated coordinate positions, the lateral shift amounts in the X and Y directions of each shot area are calculated (back-calculated) from Expressions 9 and 10, and using the lateral shift amounts, each shot area is calculated. The coordinate position (first shot arrangement) is corrected. As a result, the coordinate positions (second shot arrays) of all the shot areas on the wafer shown in FIG. 5 are obtained. Therefore, by controlling the movement position of the wafer W (wafer stage WS) based on the second shot arrangement, each shot area is sequentially and accurately aligned (positioned) with respect to the reference position (exposure position). Becomes possible.

As described above, in the present embodiment, even if the wafer is partially expanded, high-precision and high-speed operation can be performed without increasing the number of sample shots and without performing special EGA calculation such as weighting. The coordinate position of the shot area can be calculated, and alignment accuracy can be improved over the entire surface of the wafer. In this embodiment, the case where the central portion of the wafer is bulged (FIG. 5) has been described. The effect can be obtained.

Next, an alignment method according to a fourth embodiment of the present invention will be described. This embodiment also describes a case where the wafer shown in FIG. 5 is aligned, but differs from the third embodiment in that the flatness of the wafer is not measured in advance. In this embodiment, in the apparatus shown in FIGS. 2 and 3, first, the LSA system 17 measures each coordinate position of a plurality of sample shots selected in advance. At this time, after using the surface position detection systems 18 and 19, the Z stage LS is tilted so that the surface is substantially parallel to a plane including the orthogonal coordinate system XY for each sample shot, and then the coordinate position of each sample shot is changed. It shall be measured. Each coordinate position obtained as a result is substantially equal to the coordinate position of each sample shot in a state where the wafer is apparently suctioned to the holder substantially flat. Thereafter, the conventional EGA calculation (formulas 1 and 2) is performed using the plurality of coordinate positions measured earlier.
Is performed to calculate the coordinate positions of all shot areas on the wafer. Next, the movement position of wafer stage WS is controlled according to the calculated coordinate position, and each shot area is positioned with respect to the exposure position. At this time, the shot area,
In particular, the shot area located at the center of the wafer is positioned shifted from the exposure position due to the swelling of the wafer. Therefore, after positioning any one shot area to be aligned in accordance with the previously calculated coordinate position, the inclination of the surface of the area (inclination with respect to the orthogonal coordinate system XY) is detected using the surface position detection systems 18 and 19. Then, using the detected values, the lateral shift amounts in the X and Y directions of the shot area to be aligned are calculated (back calculation) from Expressions 9 and 10. Then, by positioning the wafer stage WS with an offset corresponding to the amount of the lateral shift and shifted from the previously calculated coordinate position, the shot region to be aligned is accurately positioned with respect to the exposure position. Hereinafter, the above-described lateral displacement amount is detected for each shot area, and the previously calculated coordinate position is corrected using the detected amount as an offset.
By positioning S, each shot area can be sequentially and accurately aligned (positioned) with respect to the exposure position.

As described above, even in the present embodiment, even if the wafer to be aligned is partially expanded, the number of sample shots is not increased, and a special EGA calculation such as weighting is not performed. It is possible to calculate the coordinate positions of all shot areas at high speed, and it is not necessary to measure the flatness of the wafer in advance, so that the alignment accuracy can be improved over the entire surface of the wafer without lowering the throughput. It becomes possible.
In this embodiment, the case where the central portion of the wafer is bulged (FIG. 5) has been described. The effect can be obtained.

When the reticle pattern is overlaid and exposed for each shot area, the best imaging plane of the projection optical system PL must exactly match the surface of the shot area. The inclination of the shot area (inclination with respect to the best imaging plane) is detected using the detection systems 18 and 19, and the Z stage LS is inclined based on the detected value. At this time, the shot area also shifts relative to the exposure position in the orthogonal coordinate system XY with the inclination of the Z stage LS, and although the coordinate position of the shot area is accurately calculated, the final shot area is obtained. The alignment accuracy is reduced. Therefore, in the present embodiment, the surface position detection systems 18, 1
9, the amount of shift in the X and Y directions when the Z stage LS is tilted is predicted using the detected value, and the predicted shift amount is calculated together with the lateral shift amount. It is desirable to determine the final coordinate position of the shot area in consideration of the above.

Since the surface position detecting systems 18 and 19 are calibrated so that a plane including the orthogonal coordinate system XY is used as a zero point reference, the detected values can be used as they are in calculating the predicted shift amount. Can not. For this reason,
Projection optical system PL on a plane including rectangular coordinate system XY in advance
The inclination of the best imaging plane is obtained in advance, and this inclination amount is given as an offset to the detection values of the surface position detection systems 18 and 19,
It is desirable to predict the shift amount in the X and Y directions when the Z stage LS is tilted using the corrected value. Further, in this embodiment, the coordinate position of the sample shot is measured in a state where the shot surface and the plane including the rectangular coordinate system XY are substantially parallel to each other, but the position between the shot surface and the plane including the rectangular coordinate system XY is measured. The coordinate position is measured in a state where the tilt remains, and at this time, the surface position detecting systems 18 and 1 are used.
The coordinate position may be corrected based on the amount of inclination detected in step 9, and this correction value may be used for EGA calculation.

Here, when the shape of the wafer (the bulge) can be clearly specified, as shown in FIG. 5, for example, from inside the (flat) portion (the outer peripheral portion of the wafer in FIG. 5) which is not affected by the bulge. By selecting all the sample shots, there is no need to perform coordinate conversion (correction of the coordinate position based on the amount of lateral displacement) using the amount of inclination of the shot surface due to the bulging, and various errors that may be caused by performing the coordinate conversion are eliminated. It is possible to reduce the time required for removal and measurement / calculation.

As described above, when the positioning methods according to the third and fourth embodiments are applied, since the height position and the inclination of the shot surface are measured, it is necessary to realize a high-precision alignment. Ideally, there is no unevenness in the shot area. However, in actuality, unevenness occurs in the shot region due to unevenness in application of the resist or the like, but a decrease in alignment accuracy due to the unevenness is negligible. In order to reduce this effect, a collimator type sensor is used as a sensor for detecting the inclination of the shot surface, and a sensor for detecting the height position of the shot surface at a plurality of points in the shot area. It is desirable to use one that can detect the height position and use the average value of each height position in the above calculation. The collimator type is effective in that the average inclination of the entire shot can be detected. still,
A sensor capable of detecting height positions at a plurality of points in the shot area may be used as the surface position detection system. In this case, it is not necessary to separately provide a sensor for detecting the inclination of the shot surface.

In the above embodiment, the nonlinear distortion due to the bulging generated when the wafer is attracted to the holder is considered. However, the present invention can be applied to the nonlinear distortion caused by other factors. Can be obtained. Further, of the plurality of sample shots selected in advance, for a sample shot in which mark measurement is impossible or the measured value is suspect (a large error), a shot area near the shot is newly sampled. A shot may be designated, and the coordinate position of the designated sample shot may be used for the EGA calculation.

In all of the embodiments described above, the case where the LSA system is used as the alignment sensor has been described. However, any type of alignment sensor may be used. That is, regardless of the TTR system, the TTL system, or the off-axis system, the detection system is the LSA system as described above, the image processing system such as the FIA system 20, or the two-beam interference system such as the LIA system. Any of the methods may be used. Further, the alignment method of the present invention may be realized by software or hardware in the exposure apparatus. In addition, the present invention can be applied to various types of exposure apparatuses including a step-and-repeat type, a step-and-scan type, or a proximity type exposure apparatus (projection type exposure apparatus, X-ray exposure apparatus, etc.), a repair apparatus, The present invention can be applied to a wafer prober or the like.

As described above, according to the present invention, even if a local alignment error (nonlinear distortion) occurs in a substrate in which a plurality of processing regions are regularly arranged, local distortion in the substrate can be reduced. (Especially, non-linear components), it is possible to perform high-accuracy positioning on the entire surface of the substrate. Moreover, since the alignment data used to determine the coordinate position of each processing area on the substrate is always the same, there is no need to select the alignment data to be used for each processing area, and the amount of calculation can be reduced. At the same time, it is not necessary to increase the number of sample shots, and a decrease in throughput can be prevented. In particular, in the semiconductor manufacturing process which is increasingly diversified in the future, the size of the semiconductor substrate becomes larger, and the substrate itself undergoes various heat treatments, and the non-linear component of the expansion and contraction of the substrate itself may become large. Positioning satisfying the accuracy can be performed. According to the first and eighteenth aspects of the present invention, the degree of weighting (parameter S in Equations 4 and 6) can be changed, so that the situation (required alignment accuracy, characteristic of nonlinear distortion, step pitch, alignment) can be changed. It can be set to an optimum degree according to the measurement reproducibility of the sensor). That is, in the present invention, since the parameter S can be set to an appropriate value, an intermediate effect between the EGA method and the D / D method can be obtained. Also
The inventions according to claims 3 and 19 are particularly effective for “regular, especially point-symmetric, non-linear distortion”. Also
According to the invention of claims 13 , 15 , 24, and 25 ,
Even if there is a bulge in an arbitrary portion of the substrate, the coordinate positions of all the processing regions on the substrate can be accurately determined, and the alignment accuracy can be improved without increasing the number of sample shots.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an alignment method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a projection exposure apparatus suitable for applying the alignment method according to the embodiment of the present invention.

FIG. 3 is a block diagram of a control system of the projection exposure apparatus shown in FIG.

FIG. 4 is a diagram for explaining an alignment method according to a second embodiment of the present invention.

FIG. 5 is a view showing a state of a wafer to which the alignment method according to the embodiment of the present invention is applied.

FIG. 6 is a graph showing a shift amount of each shot area on the wafer having the nonlinear distortion shown in FIG. 5 from an ideal lattice.
map.

FIG. 7 is a diagram for explaining a method of determining a parameter S in the alignment method according to the first and second embodiments.

FIG. 8 is a diagram for explaining a method of determining a parameter S in the alignment method according to the first and second embodiments.

FIG. 9 is a diagram showing an example of an arrangement of sample shots suitable for the alignment method according to the first embodiment.

FIG. 10 is a diagram for explaining non-linear distortion to which the alignment method according to the first and second embodiments is applied;

FIG. 11 is a view for explaining a state of mark position measurement by the LSA system.

FIG. 12 is a view for explaining how mark positions are measured by the FIA system.

FIG. 13 is a view for explaining a state of mark position measurement by the LIA system.

FIG. 14 is a diagram for explaining the principle of a positioning method according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Main controller 18, 19 Surface position detection system W wafer WS Wafer stage 100 EGA calculation unit 101 Weight generation unit

Continuation of front page (56) References JP-A-2-294015 (JP, A) JP-A-4-116913 (JP, A) JP-A-3-287001 (JP, A) JP-A-4-148529 (JP) JP-A-5-217848 (JP, A) JP-A-6-196384 (JP, A) JP-A-4-134813 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) H01L 21/027 G03F 9/00 (54) [Title of the Invention] Alignment apparatus, exposure apparatus using the alignment apparatus, alignment method, exposure method including the alignment method, device manufacturing including the exposure method Method and device manufactured by the device manufacturing method

Claims (28)

(57) [Claims] 1. A method according to claim 1, wherein each of a plurality of processing regions regularly formed on a substrate in accordance with a design arrangement coordinate is aligned with a predetermined reference position in a stationary coordinate system which defines a movement position of the substrate. Detecting means for detecting first coordinate position information on a coordinate position in the stationary coordinate system of at least three specific processing regions on the substrate; and the at least three detected by the detecting means. One of a plurality of said first coordinate position information about a specific processing area, wherein
A processing area on the substrate and each of the plurality of specific processing areas
Processing on the substrate based on information about the distance between
The second coordinate position information relating to the coordinate positions of the plurality of processing regions in the stationary coordinate system is calculated by weighting each region and statistically calculating the weighted plurality of the first coordinate position information. An alignment apparatus comprising: a calculating unit; and a setting unit configured to set a degree of the weighting in the calculating unit. 2. The computer according to claim 1, wherein the calculating means is an arbitrary processing unit on the substrate.
When calculating the second coordinate position information for the management area,
The specific processing area whose distance to the arbitrary processing area is short
To the first coordinate position information of the specific processing area.
2. The alignment apparatus according to claim 1, wherein the weight is increased . 3. A rule on a substrate according to an array coordinate on design.
Each of the plurality of processing regions formed as described above is transferred to the substrate.
For a given reference position in the stationary coordinate system that defines the moving position
An alignment device for positioning at least three specific processing areas on the substrate.
First coordinate position information on a coordinate position in a stationary coordinate system
Detecting means for detecting the processing area, and for each processing area on the substrate,
The distance between a predetermined point of interest and the distance
1 Distance information, between the point of interest and the specific processing area
Based on the second distance information on the distance of
In the at least three specific processing areas detected in the step
Weighting each of the plurality of first coordinate position information items
And the weighted plurality of first coordinate position information
Statistical calculation of the information in the stationary coordinate system
Second seat about coordinates position of each of said plurality of processing areas that
Calculating means for calculating the target position information.
And alignment equipment. 4. The degree of the weighting by the calculating means.
Setting means for setting
Item 4. The alignment device according to item 3 . 5. The method according to claim 1, wherein the degree of weighting is
Accuracy of alignment and characteristics of nonlinear distortion generated on the substrate
Signature, step pitch, alignment included in the detection means
At least one of the measurement reproducibility of
Responsively, set by the setting means.
The alignment device according to claim 1, 2 or 4, wherein 6. When the nonlinear distortion is larger than a predetermined value.
The degree of the weighting is determined by the setting means in advance.
Was set when the non-linear distortion was equal to or less than the predetermined value.
Specially, it is set to a value smaller than the weighting degree.
The alignment device according to claim 5, wherein 7. When the measurement reproducibility is lower than a predetermined state.
The degree of the weighting is determined by the setting means in advance.
It is set when the measurement reproducibility is higher than the specified state.
Is set to a value greater than the degree of weighting
The alignment device according to claim 5, wherein: 8. The processing means according to claim 1 , wherein said processing means is an arbitrary processing unit on said substrate.
When calculating the second coordinate position information of the
The distance to the point of interest is the distance between the point of interest and the processing area.
The closer the specific processing area is to the separation, the more the specific processing area
The weight given to the first coordinate position information is increased.
The alignment device according to claim 3 or 4, wherein 9. The point of interest is a center point of deformation of the substrate.
The alignment device according to claim 3, 4 or 8, wherein: 10. The point of interest is a substantially center point of the substrate.
The alignment device according to claim 9, wherein 11. The first coordinate position of the specific processing area
The weight given to the placement information varies according to the deformation state of the substrate.
The method according to claim 1, wherein
An alignment apparatus according to item 1. 12. The deformation of the substrate is a non-linear distortion.
The alignment device according to claim 11, wherein: 13. The method according to claim 1, wherein the substrate is defined on a substrate in accordance with a design arrangement coordinate.
Each of a plurality of processing regions regularly arranged is placed on the substrate.
For a given reference position in the stationary coordinate system that defines the movement position,
An alignment apparatus for performing at least three specific processings among the plurality of processing areas.
A coordinate position of the logical region on the stationary coordinate system.
(1) detecting means for detecting coordinate position information; and the at least three features based on flatness of the substrate.
Correcting each of the first coordinate position information of a fixed processing area
Correcting means for statistically calculating the corrected plurality of pieces of first coordinate position information
Thereby, in front of each of the plurality of processing regions on the substrate.
A second coordinate position related to the coordinate position on the stationary coordinate system
Calculating means for calculating information, according to the second coordinate position information and the flatness of the substrate,
By controlling the moving position of the substrate, the plurality of
Each processing area is sequentially aligned with the reference position
Control means for controlling the alignment. 14. The control means according to claim 1 , wherein said control means includes a
Detects height positions at several points, and based on the average value of the height positions
And determining the flatness of the substrate.
Item 14. The alignment device according to item 13 . 15. A method according to claim 1 , further comprising the steps of:
Each of a plurality of processing regions regularly arranged is placed on the substrate.
For a given reference position in the stationary coordinate system that defines the movement position,
An alignment apparatus for performing positioning by using at least three processing areas among the plurality of processing areas.
Is selected as a specific processing area, and the selected specific processing area is selected.
The surface of the area and the plane of movement of the substrate are substantially parallel
Before each of the at least three specific processing areas when
First coordinate position related to the coordinate position on the stationary coordinate system
Detecting means for detecting information; and statistically calculating the detected plurality of first coordinate position information
Each of the plurality of processing regions on the substrate
Second coordinates related to the coordinate position on the stationary coordinate system
Calculating means for calculating position information; the second coordinate position information;
Moving position of the substrate according to the tilt amount for each processing area
By controlling each of the plurality of processing areas.
Control means for sequentially aligning the reference position with the reference position.
An alignment apparatus, comprising: 16. The control means comprises a collimator type sensor.
Detecting the amount of inclination of the processing area using a computer.
The alignment apparatus according to claim 15, wherein 17. according to any one of claims 1 to 16
Alignment relative to the specified pattern by the alignment device
Transferring the predetermined pattern onto the aligned substrate.
An exposure apparatus characterized by the following . 18. The method according to claim 1 , wherein the pattern is arranged on a substrate in accordance with a design arrangement coordinate.
Each of the plurality of processing regions that are regularly formed is transferred to the substrate.
For a given reference position in the stationary coordinate system that defines the moving position
An alignment method, wherein at least three specific processing regions on the substrate are aligned.
First coordinate position information on a coordinate position in a stationary coordinate system
Detecting the at least three specific processing areas
A plurality of pieces of the first coordinate position information related to the processing on the substrate.
Between the processing area and each of the plurality of specific processing areas
On the basis of the information on
A plurality of the first coordinate positions identified and weighted.
Statistical calculation of the position information allows the static coordinate system
The coordinate position of each of the plurality of processing areas in
A calculation step of calculating two-coordinate position information ; setting for setting the degree of weighting in the calculation step
And an alignment method . 19. The method according to claim 19, wherein the substrate is defined on a substrate in accordance with a design arrangement coordinate.
Each of the plurality of processing regions formed in a regular manner is
For a given reference position in the stationary coordinate system that defines the movement position,
An alignment method, wherein at least three specific processing regions on the substrate,
First coordinate position information on a coordinate position in a stationary coordinate system
A detection step of detecting, for each processing area on the substrate,
The distance between a predetermined point of interest and the distance
Between the first distance information, the noted point and the specific processing area
Based on the second distance information on the distance of the
The at least three specific processing areas detected in
Weighting each of the plurality of first coordinate position information items
And the weighted plurality of first coordinate position information
Statistical calculation of the information in the stationary coordinate system
A second position relating to each coordinate position of the plurality of processing areas
And calculating a target position information.
Alignment method . 20. A degree of the weighting in the calculation step
Claims further comprising a setting step of setting
Item 20. The alignment method according to Item 19 . 21. The degree of weighting is required
Alignment accuracy, nonlinear distortion generated on the substrate
Features, step pitch, used in the detection process
Of the measurement repeatability of the alignment sensor
2. The method according to claim 1, wherein the setting is made in accordance with one of the following.
21. The alignment method according to 8 or 20 . 22. The point of interest is a center of deformation of the substrate.
22. A point according to claim 19, wherein
Item . 23. The first coordinate position of the specific processing area
The weight given to the placement information depends on the nonlinear deformation state of the substrate.
23. The method according to claim 18, which is changed in response to the request.
The alignment method according to claim 1. 24. A substrate is defined on a substrate in accordance with a design arrangement coordinate.
Each of a plurality of processing regions regularly arranged is placed on the substrate.
For a given reference position in the stationary coordinate system that defines the movement position,
An alignment method, wherein at least three specific processings among the plurality of processing areas are performed.
A coordinate position of the logical region on the stationary coordinate system.
(1) a detecting step of detecting coordinate position information ; and the at least three features based on flatness of the substrate.
Correcting each of the first coordinate position information of a fixed processing area
Correcting step ; statistically calculating the corrected plurality of first coordinate position information
Thereby, in front of each of the plurality of processing regions on the substrate.
A second coordinate position related to the coordinate position on the stationary coordinate system
A calculating step of calculating information ; according to the second coordinate position information and the flatness of the substrate,
By controlling the moving position of the substrate, the plurality of
Each processing area is sequentially aligned with the reference position
And a control step of: 25. A substrate is defined on a substrate in accordance with a design arrangement coordinate.
Each of a plurality of processing regions regularly arranged is placed on the substrate.
For a given reference position in the stationary coordinate system that defines the movement position,
A plurality of processing regions , wherein at least three processing regions are selected from the plurality of processing regions.
Is selected as a specific processing area, and the selected specific processing area is selected.
The surface of the area and the plane of movement of the substrate are substantially parallel
Before each of the at least three specific processing areas when
First coordinate position related to the coordinate position on the stationary coordinate system
A detecting step of detecting information ; a statistical operation of the detected plurality of pieces of the first coordinate position information
Each of the plurality of processing regions on the substrate
Second coordinates related to the coordinate position on the stationary coordinate system
An operation step of calculating position information ; the second coordinate position information and the position of the substrate with respect to the moving plane;
Moving position of the substrate according to the tilt amount for each processing area
By controlling each of the plurality of processing areas.
A control step of sequentially aligning with respect to the reference position.
An alignment method comprising : (26) The method according to any one of (18) to (25).
Position relative to the predetermined pattern
Transferring the predetermined pattern onto the aligned substrate.
An exposure method, comprising the steps of: 27. An exposure method according to claim 26,
Exposing the substrate with the predetermined pattern.
A device manufacturing method . 28. The method according to claim 27, wherein the predetermined pattern is
Manufactured through a process of transferring onto the substrate using an exposure method
A device characterized by being done .