WO2011087129A1 - Exposure method, exposure device, and manufacturing method for device - Google Patents

Abstract

Disclosed is an exposure method in which: the relationship is derived between a first component of a non-linear distortion generated on a first substrate, said first component being calculated by measuring a first number of alignment marks, and a second component which can be calculated by measuring a second number of alignment marks which is lower than the first number of alignment marks measured; the second number of alignment marks on a second substrate is measured; deformation information for the second substrate is obtained on the basis of the result of the measurement of the second number of alignment marks and the derived relationship between the first component and the second component; and the second substrate is exposed to an exposure beam on the basis of the obtained deformation information.

Description

Exposure method, exposure apparatus, and device manufacturing method

The present invention relates to an exposure method, an exposure apparatus, and a device manufacturing method.
This application claims priority based on Japanese Patent Application No. 2010-8004 for which it applied on January 18, 2010, and uses the content here.

In a manufacturing process of an electronic device such as a flat panel display, for example, an exposure apparatus that exposes a substrate with exposure light as disclosed in Patent Document 1 is used. The device is formed by stacking a plurality of patterns (patterned films) on a substrate. In the exposure process, when the image of the next pattern is superimposed on the pattern already formed on the substrate, the alignment mark of the substrate is measured, and based on the measurement result of the alignment mark, the substrate and the image of the next pattern are measured. An alignment process for performing alignment is executed.

JP 2001-215718 A

In the exposure process, when the substrate is deformed, the pattern overlay accuracy is lowered, and as a result, an exposure failure and a defective device occur. Even when the substrate is deformed, it is effective to accurately acquire the deformation information of the substrate in order to suppress a decrease in pattern overlay accuracy. When the deformation of the substrate includes a nonlinear component (nonlinear distortion), the deformation information of the substrate including the nonlinear distortion can be accurately obtained by increasing the number of measurement points of the alignment mark. However, when the number of measurement points of the alignment mark is increased, it takes time for the measurement, and the throughput may be reduced.

An object of an aspect of the present invention is to provide an exposure method and an exposure apparatus that can accurately acquire substrate deformation information and suppress the occurrence of exposure failure while suppressing a decrease in throughput. Another object of the present invention is to provide a device manufacturing method capable of suppressing the occurrence of defective devices while suppressing a decrease in throughput.

According to the first aspect of the present invention, out of the non-linear distortion generated in the first substrate, the first component that requires a first point mark measurement on the first substrate for calculation, and the first component, Deriving a relationship with a second component that can be calculated by measuring a small number of second points, executing a second number of marks on the second substrate, and marking the second point on the second substrate An exposure including: acquiring deformation information of the second substrate based on a measurement result and the relationship; and exposing the second substrate with exposure light based on the acquired deformation information. A method is provided.

According to the second aspect of the present invention, there is provided a device manufacturing method including exposing a substrate using the exposure method of the first aspect and developing the exposed substrate.

According to the third aspect of the present invention, out of the non-linear distortion occurring in the first substrate, the first component that requires the first point mark measurement on the first substrate for calculation, and the first point number. A storage device that stores a relationship with a second component that can be calculated by a small second mark measurement, a mark measurement device that performs a second mark measurement on the second substrate, and a measurement result of the mark measurement device A controller that acquires deformation information of the second substrate based on information of the storage device, and an exposure apparatus that exposes the second substrate with exposure light based on the acquired deformation information Provided.

According to a fourth aspect of the present invention, there is provided a device manufacturing method including exposing a substrate using the exposure apparatus according to the third aspect and developing the exposed substrate.

According to the aspect of the present invention, it is possible to suppress the occurrence of exposure failure while suppressing a decrease in throughput. Moreover, according to the aspect of the present invention, it is possible to suppress the occurrence of defective devices while suppressing a decrease in throughput.

It is a schematic block diagram which shows an example of the exposure apparatus which concerns on 1st Embodiment. It is a perspective view which shows an example of the exposure apparatus which concerns on 1st Embodiment. It is a schematic block diagram for demonstrating an example of the projection system which concerns on 1st Embodiment. It is a schematic diagram which shows an example of the relationship between the projection area | region of the projection system which concerns on 1st Embodiment, the detection area | region of an alignment system, and a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a figure which shows an example of the nonlinear component of a deformation | transformation of a board | substrate. It is a schematic diagram which shows an example of the number of measurement points of an alignment mark. It is a flowchart which shows an example of the exposure method which concerns on 1st Embodiment. It is a schematic diagram which shows an example of a 1st component and a 2nd component among the nonlinear distortions which arise in a board | substrate. It is a schematic diagram which shows an example of the number of measurement points of an alignment mark. It is a flowchart which shows an example of the exposure method which concerns on 2nd Embodiment. It is a flowchart which shows an example of the device manufacturing method which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ orthogonal coordinate system. A predetermined direction in the horizontal plane is defined as an X-axis direction, a direction orthogonal to the X-axis direction in the horizontal plane is defined as a Y-axis direction, and a direction orthogonal to each of the X-axis direction and the Y-axis direction (that is, a vertical direction) is defined as a Z-axis direction. Further, the rotation (inclination) directions around the X axis, Y axis, and Z axis are the θX, θY, and θZ directions, respectively.

<First Embodiment>
A first embodiment will be described. FIG. 1 is a schematic block diagram showing an example of an exposure apparatus EX according to the first embodiment, and FIG. 2 is a perspective view. 1 and 2, an exposure apparatus EX includes a mask stage 1 that can move while holding a mask M, a substrate stage 2 that can move while holding a substrate P, and a drive system 3 that moves the mask stage 1. A driving system 4 that moves the substrate stage 2, an illumination system IS that illuminates the mask M with the exposure light EL, a projection system PS that projects an image of the pattern of the mask M illuminated by the exposure light EL onto the substrate P, A control device 5 that controls the operation of the entire exposure apparatus EX, and a storage device 5R that is connected to the control device 5 and stores various types of information related to exposure are provided.

The mask M includes a reticle on which a device pattern projected onto the substrate P is formed. The substrate P includes, for example, a base material such as a glass plate and a photosensitive film (coated photosensitizer) formed on the base material. In the present embodiment, the substrate P includes a large glass plate, and the size of one side of the substrate P is, for example, 500 mm or more. In the present embodiment, a rectangular glass plate having a side of about 3000 mm is used as the base material of the substrate P.

The exposure apparatus EX of the present embodiment also includes an interferometer system 6 that measures position information of the mask stage 1 and the substrate stage 2, and a first detection that detects position information of the surface (lower surface, pattern formation surface) of the mask M. The system 7 includes a second detection system 8 that detects position information on the surface (exposure surface, photosensitive surface) of the substrate P, and an alignment system 9 that performs alignment mark measurement on the substrate P.

Further, the exposure apparatus EX includes a body 13. The body 13 includes, for example, a base plate 10 disposed on a support surface (for example, floor surface) FL in a clean room via a vibration isolation table BL, a first column 11 disposed on the base plate 10, and a first column 11 And a second column 12 disposed on the surface. In the present embodiment, the body 13 supports each of the projection system PS, the mask stage 1 and the substrate stage 2. In the present embodiment, the projection system PS is supported by the first column 11 via the surface plate 14. The mask stage 1 is supported so as to be movable with respect to the second column 12. The substrate stage 2 is supported so as to be movable with respect to the base plate 10.

In the present embodiment, the projection system PS has a plurality of projection optical systems. The illumination system IS has a plurality of illumination modules corresponding to a plurality of projection optical systems. Further, the exposure apparatus EX of the present embodiment projects an image of the pattern of the mask M onto the substrate P while moving the mask M and the substrate P synchronously in a predetermined scanning direction. That is, the exposure apparatus EX of the present embodiment is a so-called multi-lens scan exposure apparatus.

In the present embodiment, the projection system PS has seven projection optical systems PL1 to PL7, and the illumination system IS has seven illumination modules IL1 to IL7. The number of projection optical systems and illumination modules is not limited to seven. For example, the projection system PS may have 11 projection optical systems, and the illumination system IS may have 11 illumination modules.

The illumination system IS can irradiate the predetermined illumination areas IR1 to IR7 with the exposure light EL. The illumination areas IR1 to IR7 are included in the irradiation areas of the exposure light EL emitted from the illumination modules IL1 to IL7. In the present embodiment, the illumination system IS illuminates each of the seven different illumination areas IR1 to IR7 with the exposure light EL. The illumination system IS illuminates portions of the mask M arranged in the illumination regions IR1 to IR7 with exposure light EL having a uniform illuminance distribution. In the present embodiment, for example, bright lines (g line, h line, i line) emitted from a mercury lamp are used as the exposure light EL emitted from the illumination system IS.

The mask stage 1 is movable with respect to the illumination areas IR1 to IR7 while holding the mask M. The mask stage 1 includes a mask holding unit 15 that can hold the mask M. The mask holding unit 15 includes a chuck mechanism that can vacuum-suck the mask M, and holds the mask M in a releasable manner. In the present embodiment, the mask holding unit 15 holds the mask M so that the lower surface (pattern forming surface) of the mask M and the XY plane are substantially parallel. The drive system 3 includes, for example, a linear motor, and can move the mask stage 1 on the guide surface 12G of the second column 12. In the present embodiment, the mask stage 1 operates in the three directions of the X axis, the Y axis, and the θZ direction on the guide surface 12G in a state where the mask M is held by the mask holding unit 15 by the operation of the drive system 3. It is movable.

The projection system PS can irradiate the predetermined projection areas PR1 to PR7 with the exposure light EL. The projection areas PR1 to PR7 correspond to the irradiation areas of the exposure light EL emitted from the projection optical systems PL1 to PL7. In the present embodiment, the projection system PS projects a pattern image on each of seven different projection regions PR1 to PR7. The projection optical system PS projects an image of the pattern of the mask M on the portion of the substrate P arranged in the projection areas PR1 to PR7 with a predetermined projection magnification.

The substrate stage 2 is movable with respect to the projection regions PR1 to PR7 while holding the substrate P. The substrate stage 2 includes a substrate holding unit 16 that can hold the substrate P. The substrate holding unit 16 includes a chuck mechanism capable of vacuum-sucking the substrate P, and holds the substrate P so that the substrate P can be released. In the present embodiment, the substrate holding unit 16 holds the substrate P so that the surface (exposure surface) of the substrate P and the XY plane are substantially parallel. The drive system 4 includes, for example, a linear motor, and can move the substrate stage 2 on the guide surface 10 </ b> G of the base plate 10. In the present embodiment, the substrate stage 2 operates on the guide surface 10G with the X-axis, Y-axis, Z-axis, θX, θY, and It can move in six directions of θZ direction.

The alignment system 9 measures an alignment mark provided on the substrate P. The alignment system 9 is a so-called off-axis alignment system, and includes a plurality of microscopes 9A to 9F arranged to face the surface of the substrate P held on the substrate stage 2. Each of the microscopes 9A to 9F includes a projection unit that irradiates detection light to the detection regions AL1 to AL6, and a light receiving unit that can acquire an optical image of the alignment marks arranged in the detection regions AL1 to AL6.

The control device 5 performs an exposure process so that the pattern image of the mask M formed by the projection system PS is superimposed on the pattern already formed on the substrate P. During the exposure process, the control device 5 measures the alignment mark of the substrate P, and executes an alignment process for aligning the substrate P and the pattern image of the mask M based on the measurement result of the alignment mark.

FIG. 3 is a diagram showing an example of the projection system PS, the alignment system 9, and the substrate stage 2 arranged in the projection regions PR1 to PR7 according to the present embodiment.

The first projection optical system PL1 will be described. In FIG. 3, the first projection optical system PL1 projects an image of the pattern of the mask M illuminated with the exposure light EL by the first illumination module IL1 onto the substrate P. The first projection optical system PL1 includes an image plane adjustment unit 33, a shift adjustment unit 34, two sets of catadioptric optical systems 31, 32, a field stop 35, and a scaling adjustment unit 36.

The exposure light EL irradiated to the illumination area IR1 and transmitted through the mask M enters the image plane adjustment unit 33. The image plane adjustment unit 33 can adjust the position of the image plane of the first projection optical system PL1 (position in the Z axis, θX, and θY directions). The image plane adjustment unit 33 is disposed at a position that is optically conjugate with respect to the mask M and the substrate P. The image plane adjustment unit 33 includes a first optical member 33A and a second optical member 33B, and a drive device (not shown) that can move the first optical member 33A relative to the second optical member 33B. The first optical member 33A and the second optical member 33B are opposed to each other through a predetermined gap by a gas bearing. The first optical member 33A and the second optical member 33B are glass plates capable of transmitting the exposure light EL, and each have a wedge shape. The control device 5 can adjust the position of the image plane of the first projection optical system PL1 by operating the drive device and adjusting the positional relationship between the first optical member 33A and the second optical member 33B. . The exposure light EL that has passed through the image plane adjustment unit 33 enters the shift adjustment unit 34.

The shift adjusting unit 34 can shift the pattern image of the mask M on the substrate P in the X-axis direction and the Y-axis direction. The exposure light EL transmitted through the shift adjustment unit 34 enters the first set of catadioptric optical system 31. The catadioptric optical system 31 forms an intermediate image of the pattern of the mask M. The exposure light EL emitted from the catadioptric optical system 31 is supplied to the field stop 35.

The field stop 35 is disposed at the position of the intermediate image of the pattern formed by the catadioptric optical system 31. The field stop 35 defines the projection region PR1. In the present embodiment, the field stop 35 defines the projection region PR1 on the substrate P in a trapezoidal shape. The exposure light EL that has passed through the field stop 35 enters the second set of catadioptric optical system 32.

The catadioptric optical system 32 is configured in the same manner as the catadioptric optical system 31. The exposure light EL emitted from the catadioptric optical system 32 enters the scaling adjustment unit 36. The scaling adjustment unit 36 can adjust the magnification (scaling) of the pattern image of the mask M. The exposure light EL that has passed through the scaling adjustment unit 36 is irradiated onto the substrate P. In the present embodiment, the first projection optical system PL1 projects an image of the pattern of the mask M onto the substrate P at an erecting equal magnification.

The above-described image plane adjustment unit 33, shift adjustment unit 34, and scaling adjustment unit 36 constitute an image formation characteristic adjustment device 30 that adjusts the image formation characteristic (optical characteristic) of the first projection optical system PL1. The imaging characteristic adjusting device 30 is capable of adjusting the position of the image plane of the first projection optical system PL1 with respect to the six directions of the X axis, the Y axis, the Z axis, the θX, the θY, and the θZ directions. The magnification can be adjusted.

The first projection optical system PL1 has been described above. The second to seventh projection optical systems PL2 to PL7 have the same configuration as the first projection optical system PL1. A description of the second to seventh projection optical systems PL2 to PL7 is omitted.

FIG. 4 is a schematic diagram showing an example of the positional relationship between the projection regions PR1 to PR7, the detection regions AL1 to AL6, and the substrate P, and shows the positional relationship in a plane including the surface of the substrate P. As shown in FIG. 4, in the present embodiment, the surface of the substrate P has a plurality of exposure areas (processed areas) PA1 to PA6 onto which an image of the pattern of the mask M is projected. In the present embodiment, the surface of the substrate P has six exposure areas PA1 to PA6. The exposure areas PA1, PA2, and PA3 are arranged at approximately equal intervals in the Y axis direction, and the exposure areas PA4, PA5, and PA6 are arranged at approximately equal intervals in the Y axis direction. The exposure areas PA1, PA2, and PA3 are arranged on the + X side with respect to the exposure areas PA4, PA5, and PA6.

In the present embodiment, each of the projection areas PR1 to PR7 is a trapezoid in the XY plane. In the present embodiment, projection regions PR1, PR3, PR5, PR7 by the projection optical systems PL1, PL3, PL5, PL7 are arranged at substantially equal intervals in the Y-axis direction, and projection regions PR2 by the projection optical systems PL2, PL4, PL6 are arranged. , PR4, PR6 are arranged at substantially equal intervals in the Y-axis direction. The projection areas PR1, PR3, PR5, PR7 are arranged on the −X side with respect to the projection areas PR2, PR4, PR6. Further, the projection areas PR2, PR4, and PR6 are arranged between the projection areas PR1, PR3, PR5, and PR7 with respect to the Y-axis direction.

In this embodiment, the detection areas AL1 to AL6 by the microscopes 9A to 9F are arranged on the −X side with respect to the projection areas PR1 to PR7. The detection areas AL1 to AL6 are arranged apart from each other in the Y-axis direction. Among the plurality of detection areas AL1 to AL6, the distance between the two outer detection areas AL1 and AL6 in the Y-axis direction is set so that the two outer exposure areas PA1 ( The distance between the −Y side edge of PA4) and the + Y side edge of exposure area PA3 (PA6) is substantially equal.

The alignment system 9 detects a plurality of alignment marks m1 to m6 provided on the substrate P. In the present embodiment, six alignment marks m1 to m6 are arranged on the substrate P so as to be separated from each other in the Y axis direction, and groups of these alignment marks m1 to m6 are arranged at four places separated in the X axis direction. . Alignment marks m1 and m2 are provided adjacent to both ends of exposure areas PA1 and PA4, and alignment marks m3 and m4 are provided adjacent to both ends of exposure areas PA2 and PA5. m6 is provided adjacent to both ends of the exposure areas PA3 and PA6.

In this embodiment, microscopes 9A to 9F (detection areas AL1 to AL6) are arranged corresponding to the six alignment marks m1 to m6 arranged on the substrate P so as to be separated from each other in the Y-axis direction. The microscopes 9A to 9F are provided so that the alignment marks m1 to m6 are simultaneously arranged in the detection areas AL1 to AL6. The alignment system 9 can simultaneously detect the six alignment marks m1 to m6 using the microscopes 9A to 9F.

Incidentally, the substrate P may be deformed. The substrate P may be heated by, for example, various process processes performed before and after the exposure process. As a result, the substrate P may be deformed (thermally deformed). Further, the substrate P may be deformed (distorted) due to the holding state of the substrate holding unit 16. Note that the holding state of the substrate holding unit 16 includes, for example, suction unevenness of the suction mechanism provided in the substrate holding unit 16.

The deformation of the substrate P can be divided into a linear component and a non-linear component. In the following description, the nonlinear component of the deformation of the substrate P is appropriately referred to as nonlinear distortion.

Non-linear component (non-linear distortion) can be expressed by a polynomial. The nonlinear component can be expressed by a cubic polynomial, for example. The nonlinear component can be expressed by, for example, the following third-order polynomial by developing by the method of least squares.

5, 6 and 7 show the developed second-order nonlinear components, and FIGS. 8, 9, 10 and 11 show the developed third-order nonlinear components. Equation (1) indicates the amount of displacement from the reference lattice point in the X-axis direction, and Equation (2) indicates the amount of displacement from the reference lattice point in the Y-axis direction.

As described above, the exposure process includes a process of projecting an image of the pattern of the mask M so as to be superimposed on the pattern already formed on the substrate P. In the exposure process, an alignment process is performed to align the substrate P and the pattern image. When the substrate P is deformed, it is effective to accurately acquire deformation information of the substrate P in order to suppress a decrease in pattern overlay accuracy.

When nonlinear distortion occurs in the substrate P, deformation information relating to the nonlinear distortion can be acquired by increasing the number of measurement points of the alignment mark. That is, as the number of alignment mark measurement points increases, information on higher-order components of nonlinear distortion can be acquired. In order to obtain information on higher-order nonlinear components among the deformation information of the substrate P, it is effective to arrange a large number of alignment marks on the substrate P and to measure these many alignment marks with the alignment system 9.

For example, in order to calculate the x ² component in the Y-axis direction among the nonlinear components, as shown in the schematic diagram of FIG. 12, alignment marks are arranged at a plurality of different positions on the substrate P at least in the X-axis direction, It is necessary to measure all of these alignment marks.

As described above, by arranging a large number of alignment marks on the substrate P and measuring the large number of alignment marks by the alignment system 9, information on higher-order nonlinear components can be acquired. By acquiring up to information about higher-order nonlinear components, it is possible to satisfactorily execute correction processing for suppressing a decrease in pattern overlay accuracy. The correction process includes a process of adjusting the projection areas PR1 to PR7 using the imaging characteristic adjusting device 30.

However, if the number of alignment mark measurement points is increased, it takes time for the measurement and the throughput may be reduced.

Therefore, in the present embodiment, as shown in the flowchart of FIG. 13, out of the non-linear distortion generated in the substrate P, the first component that requires the first number of alignment mark measurements on the substrate P for calculation, and the first component A process of deriving a relationship (correlation) with a second component that can be calculated by measuring an alignment mark with a second score smaller than the score (step SA1), and a process of executing alignment mark measurement of the second score on the substrate P (step SA1) Step SA2), a process of obtaining deformation information of the substrate P based on the result measured in Step SA2 and the relationship derived in Step SA1 (Step SA3), and the substrate P based on the obtained deformation information. A process of exposing with the exposure light EL (step SA4) is executed.

In the present embodiment, the process for deriving the correlation (step SA1) is executed in advance prior to the alignment process and the exposure process (steps SA2 to SA4) for the substrate P to be exposed.

Hereinafter, the principle of this embodiment will be described. As shown in the equations (1), (2), and FIGS. 5 to 11, the nonlinear distortion can be decomposed (developed) into a plurality of components. According to the knowledge of the present inventor, it has been found that among a plurality of components of nonlinear distortion, predetermined components have a correlation.

Hereinafter, in order to simplify the description, the nonlinear component shown in FIG. 14 will be described as an example. 14 nonlinear components shown in (C) is a second-order components shown in FIG. 14 (A) (x ² component in the Y-axis direction), a second order component (xy component of the X-axis direction) shown in FIG. 14 (B) And can be disassembled. In this case, there is a correlation to the secondary component (Y-axis direction of the x ² component) and the secondary component (xy component of the X-axis direction) shown in FIG. 14 (B) shown in FIG. 14 (A).

That is, when the secondary component shown in FIG. 14 (A) is generated, a force as shown by an arrow in FIG. 14 (A) is generated as an internal stress, and the secondary shown in FIG. As a result, a non-linear distortion as shown in FIG. 14C is considered to occur. In this case, the secondary component shown in FIG. 14 (A) and the secondary component shown in FIG. 14 (B) are correlated.

Therefore, by measuring one of the secondary component shown in FIG. 14 (A) and the secondary component shown in FIG. 14 (B), based on the measurement result and the above correlation, The other component can be determined.

When obtaining the secondary component shown in FIG. 14A or obtaining the nonlinear component shown in FIG. 14C, it is necessary to measure eight alignment marks as shown in FIG. On the other hand, when obtaining the secondary component shown in FIG. 14B, it is sufficient to measure four alignment marks as shown in FIG.

In this embodiment, the correlation between the secondary component shown in FIG. 14A and the secondary component shown in FIG. 14B is derived in advance prior to the exposure of the substrate P (step SA1). When the substrate P is actually exposed, measurement of four alignment marks is executed on the substrate P as shown in FIG. 15 (step SA2). Based on the measurement results of the four alignment marks, the secondary component shown in FIG. 14B is obtained. Based on the measurement results of the four alignment marks measured in step SA2, that is, the secondary component shown in FIG. 14B and the correlation derived in step SA1, the secondary component shown in FIG. Is required. Since the secondary component shown in FIG. 14 (A) and the secondary component shown in FIG. 14 (B) have been obtained, information on the nonlinear component as shown in FIG. 14 (C) can be acquired (step SA3). ).

Thus, in the present embodiment, among the nonlinear distortion occurring in the substrate P, a second order component shown in FIG. 14 (A) (x ² component in the Y-axis direction), a second order component shown in FIG. 14 (B) The correlation with (xy component in the X-axis direction) is derived in advance. As shown in FIG. 12, the secondary components shown in FIG. 14 (A) (x ² component in the Y-axis direction), that require alignment mark measurement of eight points in the substrate P for the calculation of the second order component It is an ingredient. On the other hand, as shown in FIG. 15, the secondary component (xy component in the X-axis direction) shown in FIG. 14B is a component that can be calculated by measuring four alignment marks on the substrate P. The correlation obtained in step SA1 is stored in the storage device 5R.

In the following description, the secondary component shown in FIG. 14A, which requires 6-point alignment mark measurement on the substrate P in order to calculate the component, is appropriately referred to as a first component, and is smaller than 6 points 4 The secondary component shown in FIG. 14B that can be calculated by measuring the alignment mark of the points is appropriately referred to as a second component.

The controller 5 measures the four alignment marks on the substrate P using the alignment system 9 when exposing the substrate P (step SA2). The control device 5 can acquire deformation information of the substrate P based on the measurement result of the four alignment marks measured in step SA2 and the information on the correlation stored in the storage device 5R (step). SA3).

The control device 5 exposes the substrate P with the exposure light EL based on the acquired deformation information (step SA4). The control device 5 adjusts the exposure conditions based on the acquired deformation information, and exposes the substrate P based on the adjusted exposure conditions. The adjustment of the exposure condition includes adjusting the projection regions PR1 to PR7 using the imaging characteristic adjusting device 30. Based on the acquired deformation information of the substrate P, the control device 5 uses the image formation characteristic adjustment device 30 to prevent the pattern overlay accuracy from degrading (so that an overlay error does not occur). At least one of the position, size, and shape of PR7 is adjusted, and the substrate P is exposed with the exposure light EL that is irradiated onto the adjusted projection areas PR1 to PR7.

In the present embodiment, the control device 5 obtains the correlation between the first component shown in FIG. 14 (A) and the second component shown in FIG. 14 (B) by multiple regression analysis. That is, in step SA1, the control device 5 calculates the first component shown in FIG. 14A based on the measurement results of the six alignment marks, and calculates the first component shown in FIG. The second component shown in FIG. 14B is calculated, and the calculated first component and second component are subjected to multiple regression analysis to derive the correlation (relationship) between the first component and the second component. In the present embodiment, the correlation between the first component and the second component includes a predetermined relational expression. In the present embodiment, a linear expression is adopted as the predetermined relational expression. That is, in the present embodiment, the derivation of the correlation (relationship) between the first component and the second component includes derivation of a linear relationship between the first component and the second component.

For example, a relational expression is calculated using multiple regression analysis with the second component shown in FIG. 14B as an explanatory variable and the first component shown in FIG. 14A as an objective function. At this time, it is preferable to use a stepwise method or the like for selecting an effective objective variable. The obtained relational expression is stored in the storage device 5R.

According to the knowledge of the present inventor, the correlation (relational expression) changes depending on, for example, the shape, size, and thickness of the substrate P, and various processing conditions applied to the substrate P. Conceivable.

As described above, according to the present embodiment, the correlation (relational expression) between the first component and the second component is obtained in advance (step SA1), and the four-point alignment is performed during the actual exposure of the substrate P. By knowing how much the second component shown in FIG. 14B is generated based on the measurement result of the mark, the first component shown in FIG. 14A can be known. Further, the nonlinear component shown in FIG. 14C can also be known.

As described above, according to the present embodiment, among the nonlinear components generated on the substrate P, the first component that cannot be calculated unless the six alignment marks are measured is based on the measurement results of the four alignment marks. Can be acquired. That is, according to the present embodiment, the deformation state of the substrate P that can be derived from the measurement results measured with a large number of alignment mark measurement points with a small number of alignment mark measurement points using the correlation (relational expression) obtained in advance. Can be estimated. Accordingly, the deformation information of the substrate P as shown in FIG. 14C can be acquired without requiring a long time for the alignment mark measurement. Therefore, it is possible to suppress a decrease in overlay accuracy while suppressing a decrease in throughput, and it is possible to suppress the occurrence of exposure failure and the generation of defective devices.

In the present embodiment, the measurement of the six alignment marks may be performed a plurality of times, and the average value of the measurement results of the six alignment marks may be used for calculating the first component. Alternatively, the measurement of the four alignment marks may be performed a plurality of times, and the average value of the measurement results of the four alignment marks may be used for calculating the second component.

In the present embodiment, the nonlinear component shown in FIG. 14 has been described as an example. As described with reference to the equations (1), (2), and FIGS. 5 to 11, when the nonlinear component is expanded into a third-order polynomial, for example, there are 20 expanded components. In the present embodiment, it is possible to derive which component is correlated with which component among the 20 components by using multiple regression analysis. Moreover, the relational expression between the components having the correlation can be derived using multiple regression analysis.

It should be noted that a component having a correlation (a coupled component) is determined according to the shape of the substrate P, for example. In addition, among the components having correlation, the deformation amount of the other component is determined according to the deformation amount of one component. The amount of deformation is considered to be determined according to, for example, the conditions of the process performed on the substrate P.

Second Embodiment
Next, a second embodiment will be described. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

In the second embodiment, a more detailed procedure will be described with reference to the flowchart of FIG. First, the control device 5 starts a process for deriving a correlation (relational expression) between the first component and the second component (step SB1). In the following description, the process for deriving the correlation (relational expression) is appropriately referred to as a derivation sequence.

In the derivation sequence, the control device 5 performs an exposure process of the substrate P for deriving the correlation (relational expression) between the first component and the second component (step SB2).

The exposure in step SB2 is an exposure for deriving a correlation (relational expression). In the following description, the exposure in step SB2 is appropriately referred to as test exposure.

In the test exposure, the control device 5 exposes the substrate P by correcting only the linear component without correcting the nonlinear component by the imaging characteristic adjusting device 30. In the present embodiment, a plurality (n) of substrates P are exposed in the test exposure.

Next, the control device 5 measures each of the plurality of alignment marks provided on the substrate P using the alignment system 9 (step SB3). In the present embodiment, the control device 5 measures at least 16 alignment marks among the 24 alignment marks m1 to m6 provided on one substrate P. In the present embodiment, the control device 5 measures all 24 alignment marks m1 to m6 provided on one substrate P by using the alignment system 9.

Based on the measurement result of the alignment system 9, the control device 5 derives the 20 coefficients C ₀₀ to C ₁₉ shown in the equations (1) and (2) (step SB4). The control device 5 performs 24 alignment mark measurements on each of the n substrates P, and derives 20 coefficients C ₀₀ to C ₁₉ . As a result, (20 × n) coefficients C ₀₀ (i) to C ₁₉ (i) (where i = 1 to n) are derived.

The controller 5 performs multiple regression analysis on the above-described (20 × n) coefficients C ₀₀ (i) to C ₁₉ (i) to derive a correlation (relational expression) (step SB5). Similar to the first embodiment described above, this embodiment also employs a linear expression as a relational expression. The derived correlation (relational expression) is stored in the storage device 5R (step SB6).

As an example, when it is derived by the multiple regression analysis that there is a correlation between C ₀₅ and C ₀₀ , the linear expression can be expressed as C ₀₅ = f ₀₅ × C ₀₀ + Const ₀₅ . When it is derived that there is a correlation between C ₀₅ and C ₀₁ , the linear expression can be expressed as C ₀₅ = f ₀₅ × C ₀₁ + Const ₀₅ .

Thus, the derivation sequence ends (step SB7).

After the derivation sequence is completed, the control device 5 starts an exposure sequence including an exposure process for the substrate P for manufacturing a device (step SB8).

In the exposure sequence, a plurality of substrates P included in a lot are sequentially exposed. In the present embodiment, the substrate P used in the above-described derivation sequence is a substrate P different from the substrate P in the lot exposed in the exposure sequence.

After the substrate P for manufacturing the device is held (loaded) on the substrate stage 2 (substrate holding unit 16), the control device 5 measures the alignment mark of the substrate P using the alignment system 9 (step SB9). ). The control device 5 performs alignment mark measurement with fewer measurement points than the alignment mark measurement points measured in the alignment mark measurement process (step SB3) in the derivation sequence. As described above, the number of alignment mark measurement points in step SB3 is 24 points. In the present embodiment, as shown in the schematic diagram of FIG. 12, the control device 5 performs eight alignment mark measurements in step SB9.

Control device 5 calculates the second component based on the measurement result of the eight alignment mark measurements (step SB10). In the present embodiment, examples of the second component that can be calculated by measuring eight alignment marks and the first component that cannot be calculated from the measurement result of eight alignment mark measurements are as follows.

<Second component> [X-axis direction]: C ₀₀ , C ₀₁ , C ₀₂ , C ₀₃ , C ₀₄ , C ₀₆ , C ₀₇ [Y-axis direction]: C ₁₀ , C ₁₁ , C ₁₂ , C ₁₃ , C ₁₄ , C ₁₆ , C ₁₇ <first component> [X-axis direction]: C ₀₅ , C ₀₈ , C ₀₉ [Y-axis direction]: C ₁₅ , C ₁₈ , C ₁₉

Also, an example of the relational expression for each of the first components is as follows.

Incidentally, in step SB9, based on the measurement result of the eight alignment marks, a second component that can be calculated from the eight alignment mark measurements is obtained. Therefore, there is a possibility that a predetermined component of nonlinear distortion that cannot be obtained from the measurement result of the eight alignment mark measurement is added to the second component calculated from the eight alignment mark measurement. . In other words, although the second component obtained from the measurement result of the eight alignment mark measurements cannot be obtained from the measurement result of the eight alignment mark measurement, the component of the nonlinear distortion actually generated There is a possibility that at least a part of is added. The component to be added is considered to change depending on the position of the alignment mark to be measured.

Therefore, in the present embodiment, the control device 5 calculates the second component of the substrate P based on the measurement results of the eight alignment mark measurements, and then based on the first component that affects the second component. The second component is corrected (step SB11).

That is, when the first component has a correlation with the predetermined second component, the control device 5 corrects the second component so as to remove the influence of the first component on the second component.

As described above, in the present embodiment, the first component is C ₀₅ , C ₀₈ , C ₀₉ , C ₁₅ , C ₁₈ , and C ₁₉ . The second component is C ₀₀ , C ₀₁ , C ₀₂ , C ₀₃ , C ₀₄ , C ₀₆ , C ₀₇ , C ₁₀ , C ₁₁ , C ₁₂ , C ₁₃ , C ₁₄ , C ₁₆ , C ₁₇ . . When the coefficient of the second component included in the first component is γ, the corrected second component C _00meas , C _01meas , C _02meas , C _03meas , C _04meas , C _06meas , C _07meas , C _10meas , C _11meas , _C12meas , _C13meas , _C14meas , _C16meas , _C17meas are as follows.

The control device 5 acquires the deformation information of the substrate P based on the corrected second component and the correlation (relational expression) stored in the storage device 5R (step SB12).

The control device 5 exposes the substrate P with the exposure light EL based on the acquired deformation information (step SB13). The control device 5 adjusts the exposure conditions based on the acquired deformation information, and exposes the substrate P based on the adjusted exposure conditions. The adjustment of the exposure condition includes adjusting the projection regions PR1 to PR7 using the imaging characteristic adjusting device 30. Based on the acquired deformation information of the substrate P, the control device 5 uses the image formation characteristic adjustment device 30 to prevent the pattern overlay accuracy from degrading (so that an overlay error does not occur). At least one of the position, size, and shape of PR7 is adjusted, and the substrate P is exposed with the exposure light EL that is irradiated onto the adjusted projection areas PR1 to PR7.

Thus, the exposure sequence ends (step SB14).

As described above, also in this embodiment, it is possible to suppress the occurrence of exposure failure and the occurrence of defective devices while suppressing a decrease in throughput.

In the present embodiment, a derivation sequence different from the exposure sequence is provided, and the correlation (relational expression) is derived based on the alignment mark measurement result of the substrate P subjected to test exposure in the derivation sequence. The substrate P used in the derivation sequence is different from the substrate P in the lot used in the exposure sequence, that is, the substrate P outside the lot. When sequentially exposing a plurality of substrates P included in a lot in order to manufacture a device in an exposure sequence, a predetermined number of substrates P in the lot including the first substrate P of the lot are exposed, and the exposed plurality of substrates P The correlation (relational expression) may be derived based on the alignment mark measurement result of the substrate P. That is, in the case where a plurality of substrates P included in a lot are sequentially exposed, a correlation (relational expression) is derived from the alignment mark measurement results of a predetermined number of substrates P in the lot including the top of the lot. In the exposure processing of the substrate P other than the substrate P used to derive the correlation (relational expression), the second component is calculated with a small number of alignment mark measurement points, and the second component and the correlation are calculated. Based on the acquired deformation information, the substrate P may be exposed based on the acquired deformation information of the substrate P.

In the first and second embodiments described above, the nonlinear component is expanded into a third-order polynomial, but of course, it may be expanded into a second-order polynomial, or expanded into a fourth-order polynomial. May be. The order is arbitrary.

As the substrate P in the above-described embodiment, not only a glass substrate for a display device but also a semiconductor wafer for manufacturing a semiconductor device, a ceramic wafer for a thin film magnetic head, or an original mask (reticle) used in an exposure apparatus ( Synthetic quartz, silicon wafer) or the like is applied.

As the exposure apparatus EX, a step-and-scan type scanning exposure apparatus (scanning stepper) that scans and exposes the substrate P with the exposure light EL through the pattern of the mask M by moving the mask M and the substrate P synchronously. In addition, the pattern of the mask M is collectively exposed while the mask M and the substrate P are stationary, and is applied to a step-and-repeat type projection exposure apparatus (stepper) that sequentially moves the substrate P stepwise. Can do.

The present invention also relates to a twin-stage type exposure having a plurality of substrate stages as disclosed in US Pat. No. 6,341,007, US Pat. No. 6,208,407, US Pat. No. 6,262,796, and the like. It can also be applied to devices.

Further, the present invention relates to a substrate stage for holding a substrate as disclosed in US Pat. No. 6,897,963, European Patent Application No. 1713113, etc., and a reference mark without holding the substrate. The present invention can also be applied to an exposure apparatus that includes a formed reference member and / or a measurement stage on which various photoelectric sensors are mounted. An exposure apparatus including a plurality of substrate stages and measurement stages can be employed.

The type of the exposure apparatus EX is not limited to an exposure apparatus for manufacturing a liquid crystal display element or a display, but an exposure apparatus for manufacturing a semiconductor element that exposes a semiconductor element pattern on a substrate P, a thin film magnetic head, an image sensor (CCD) In addition, the present invention can be widely applied to an exposure apparatus for manufacturing a micromachine, MEMS, DNA chip, reticle, mask, or the like.

In each of the above-described embodiments, the position information of each stage is measured using an interferometer system including a laser interferometer. However, the present invention is not limited to this. For example, a scale (diffraction grating) provided in each stage You may use the encoder system which detects this.

In the above-described embodiment, a light-transmitting mask in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate is used. As disclosed in US Pat. No. 6,778,257, a variable shaped mask (also called an electronic mask, an active mask, or an image generator) that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed. ) May be used. Further, a pattern forming apparatus including a self-luminous image display element may be provided instead of the variable molding mask including the non-luminous image display element.

The exposure apparatus EX of the above-described embodiment is manufactured by assembling various subsystems including each component so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. To ensure these various accuracies, before and after this assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

As shown in FIG. 17, a microdevice such as a semiconductor device includes a step 201 for designing a function / performance of the microdevice, a step 202 for manufacturing a mask (reticle) based on the design step, and a substrate which is a base material of the device. Manufacturing step 203, including substrate processing (exposure processing) including exposing the substrate with exposure light using a mask pattern and developing the exposed substrate (photosensitive material) according to the above-described embodiment The substrate is manufactured through a substrate processing step 204, a device assembly step (including processing processes such as a dicing process, a bonding process, and a packaging process) 205, an inspection step 206, and the like. In step 204, the photosensitive material is developed to form an exposure pattern layer (developd photosensitive material layer) corresponding to the mask pattern, and the substrate is processed through the exposure pattern layer. It is.

It should be noted that the requirements of the above-described embodiments and modifications can be combined as appropriate. Some components may not be used. In addition, as long as it is permitted by law, the disclosure of all published publications and US patents related to the exposure apparatus and the like cited in the above-described embodiments and modifications are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 ... Mask stage, 2 ... Substrate stage, 5 ... Control device, 5R ... Memory | storage device, 9 ... Alignment system, EL ... Exposure light, EX ... Exposure apparatus, P ... Substrate

Claims (11)

1. Of the non-linear distortion generated in the first substrate, it can be calculated by a first component that requires a first point mark measurement on the first substrate and a second point mark measurement less than the first point for calculation. Deriving a relationship with the second component;
   Performing a second point mark measurement on the second substrate;
   Obtaining deformation information of the second substrate based on the result of the mark measurement of the second score on the second substrate and the relationship;
   Exposing the second substrate with exposure light based on the acquired deformation information.
2. Calculating a second component of the second substrate based on the result of mark measurement of the second score;
   Correcting the second component based on the first component affecting the second component;
   Including
   The exposure method according to claim 1, wherein the deformation information of the second substrate is acquired based on the corrected second component and the relationship.
3. Adjusting exposure conditions based on the acquired deformation information,
   The exposure method according to claim 1, wherein the second substrate is exposed based on the adjusted exposure condition.
4. The derivation of the relationship is related to a plurality of the first substrates.
   Calculating the first component based on the result of mark measurement of the first score;
   Calculating the second component based on the result of mark measurement of the second score;
   Multiple regression analysis of the calculated first and second components;
   The exposure method according to any one of claims 1 to 3, comprising:
5. The calculation of the first component includes obtaining an average value of a plurality of mark measurement results of the first score,
   The exposure method according to any one of claims 1 to 4, wherein the calculation of the second component includes obtaining an average value of a plurality of mark measurement results of the second score.
6. The exposure method according to any one of claims 1 to 5, wherein the derivation of the relationship includes deriving a linear relationship between the first component and the second component.
7. A plurality of substrates included in a lot are sequentially exposed,
   The first substrate is a substrate outside the lot,
   The exposure method according to claim 1, wherein the second substrate is a substrate in the lot.
8. A plurality of substrates included in a lot are sequentially exposed,
   The first substrate is a predetermined number of substrates in the lot including the first substrate of the lot;
   The exposure method according to any one of claims 1 to 6, wherein the second substrate is a substrate other than the first substrate in the lot.
9. Exposing the substrate using the exposure method according to any one of claims 1 to 8,
   Developing the exposed substrate. A device manufacturing method.
10. Of the non-linear distortion generated in the first substrate, it can be calculated by a first component that requires a first point mark measurement on the first substrate and a second point mark measurement less than the first point for calculation. A storage device for storing the relationship with the second component;
    A mark measuring device for executing a second point mark measurement on the second substrate;
    A control device that acquires deformation information of the second substrate based on a measurement result of the mark measurement device and information of the storage device;
    An exposure apparatus that exposes the second substrate with exposure light based on the acquired deformation information.
11. Exposing the substrate using the exposure apparatus according to claim 10;
    Developing the exposed substrate. A device manufacturing method.

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