Exposure apparatus, exposure method, and article manufacturing method
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2023-04-25
- Publication Date
- 2026-05-07
AI Technical Summary
Existing exposure apparatuses face challenges in achieving high measurement accuracy and throughput for substrate height information due to the time-consuming process of capturing and processing high-resolution pattern images.
The apparatus projects a pattern onto a substrate using a projection optical system, incorporates a stage for moving the substrate, a measurement unit to measure height positions at multiple points, and a control unit to correct the stage position based on these measurements, with measurement points assigned to sub-regions to enhance accuracy and reduce data processing time.
This approach allows for high-precision height measurement of substrate surfaces with improved throughput by optimizing the number and placement of measurement points, ensuring accurate alignment without prolonging the measurement process.
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Abstract
Description
[Technical field]
[0001] The present invention relates to an exposure apparatus, an exposure method, and an article manufacturing method. [Background technology]
[0002] There are two types of exposure equipment used in the manufacture of semiconductor devices: step-and-repeat exposure equipment (steppers) and step-and-scan exposure equipment (scanners). Steppers are lower-cost equipment than scanners, and are used in processes that do not require high resolution or high-precision overlay. In a stepper, after the stage carrying the substrate is driven to the exposure shot position, a height measurement device measures the distance from the projection lens, and the stage is focused on the projection lens according to the measurement value, and then exposure is performed.
[0003] Patent Document 1 discloses a height measurement device that measures the height of a sample based on a projected image of a two-dimensional slit. The two-dimensional slit has multiple slits arranged at a fine pitch, and the measurement light that passes through each slit is received by a two-dimensional light receiving element. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Patent No. 6491833 Summary of the Invention [Problem to be solved by the invention]
[0005] In order to obtain height information for the entire exposure area, it is necessary to capture a pattern image of the exposure area with a high-resolution camera, transfer the image data obtained by capturing the image to a control unit, and process the image data in the control unit, and the time required for these operations can be a problem. In an exposure apparatus, productivity such as throughput is also an important performance index, so it is desirable to obtain height information with high accuracy in as short a time as possible.
[0006] The present invention provides a technique that is advantageous in achieving both measurement accuracy and throughput in relation to measuring the height of a substrate surface. [Means for solving the problem]
[0007] According to one aspect of the present invention, there is provided an exposure apparatus that projects a pattern of an original onto a substrate using a projection optical system to expose the substrate, the exposure apparatus comprising: a stage that holds and moves the substrate; a measurement unit that measures the height position of the substrate held by the stage at a plurality of measurement points in an exposure area; and a control unit that controls the measurement unit and corrects the position of the stage based on the results of the measurement so that the amount of deviation of the height position relative to the image plane of the projection optical system is reduced, wherein the control unit sets the plurality of measurement points so that one measurement point is assigned to each of a plurality of sub-areas obtained by dividing the exposure area based on the position or size of the exposure area. Effect of the Invention
[0008] According to the present invention, it is possible to provide a technique that is advantageous in achieving both measurement accuracy and throughput in relation to height measurement of a substrate surface. [Brief description of the drawings]
[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of an exposure apparatus. [Diagram 2] FIG. 2 is a diagram showing the configuration of a measurement unit. [Diagram 3] 5A and 5B are diagrams showing examples of light projection patterns projected onto a substrate. [Figure 4] FIG. 13 is a graph showing the relationship between the number of measurement points and a primary plane correction residual. [Diagram 5] FIG. 4 is a diagram for explaining a method of dividing a measurement area. [Figure 6] FIG. 4 is a diagram showing measurement positions in each sub-region. [Figure 7] 1A and 1B are diagrams showing examples of a plurality of chip regions formed in a shot region. [Figure 8]FIG. 4 is a diagram showing measurement positions in each chip area. [Figure 9] 1A and 1B are diagrams showing examples of partial shot regions located on the outer periphery of a substrate. [Figure 10] 6A and 6B are diagrams for explaining a method of dividing a measurement region in a partial shot region. [Figure 11] FIG. 13 is a diagram showing measurement positions determined for each sub-area of a partial shot area. [Figure 12] 4 is a flowchart of an exposure method. [Figure 13] FIG. 13 is a diagram showing an example of a height map within a sample shot area. [Figure 14] 11A and 11B are diagrams for explaining a method of determining a measurement position using a differential value of a height position measurement value. [Figure 15] 11A and 11B are diagrams for explaining a method of determining a measurement position based on measurement repeatability. [Figure 16] FIG. 13 is a diagram showing an example of distribution measurement points that exist in advance over the entire surface of an exposure area. [Figure 17] 11A and 11B are diagrams for explaining a process of setting a plurality of measurement points by selecting a part of the distribution measurement points. [Figure 18] 4 is a flowchart of an exposure method. [Figure 19] FIG. 11 is a diagram showing an example of a measurement point selection result. [Figure 20] 4 is a flowchart of an exposure method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.
[0011] First Embodiment Example 1 FIG. 1 is a diagram showing the configuration of an exposure apparatus 100 according to the first embodiment. The exposure apparatus 100 is one form of a lithography apparatus used in a photolithography process, which is a manufacturing process for devices or flat panels. The exposure apparatus 100 projects a pattern of an original onto a substrate using a projection optical system, thereby exposing the substrate. The exposure apparatus 100 exposes the substrate via an original (mask) by a step-and-repeat method or a step-and-scan method, and transfers the pattern of the mask onto the substrate. Although there is no limitation on the exposure method, the exposure apparatus 100 will be described below as being a step-and-repeat type exposure apparatus.
[0012] The illumination optical system 102 guides light from the light source 101 to illuminate a mask 103, which is an original. The light source 101 may be composed of an i-line mercury lamp, an excimer laser, or the like. A pattern to be projected is drawn on the mask 103. The light that passes through the mask 103 reaches a substrate 108 on a stage 105 through a projection optical system 104. The stage 105 is a substrate stage that holds and moves the substrate 108. The image of the mask pattern projected on the substrate 108 reacts with a photosensitive material such as a resist that has been applied to the surface of the substrate 108 in advance. By developing this, a pattern is formed on the surface of the substrate 108. Exposure is performed over the entire surface of the substrate 108 by repeatedly stepping the stage 105 that holds the substrate 108 and exposing a predetermined exposure area (shot area). During the exposure operation, the position and orientation of the stage 105 are measured with high precision by a position measurement device such as an interferometer or an encoder (not shown), thereby achieving high-precision overlay exposure.
[0013] During exposure, in order to align the height and inclination of the substrate with respect to the position of the mask pattern image, the height of substrate 108 is measured by measurement unit 106, and at least one of the height and inclination of stage 105 is controlled based on the measurement result. Note that, hereinafter, controlling at least one of the height and inclination of stage 105 may also be simply referred to as "aligning the height of the substrate."
[0014] The configuration of the measurement unit 106 will be described with reference to Fig. 2. The measurement unit 106 detects the height of a point of interest within a detection area. The measurement unit 106 has a light projecting unit 201 and a light receiving unit 205.
[0015] The light projection unit 201 may include a light source 202 that obliquely incidents light on the surface of the test object (substrate 108) on the stage 105, a two-dimensionally arranged light projection pattern 203, and a light projection optical system 204 for projecting the light projection pattern 203 onto the test object. However, depending on the type of the light source 202 and the distance between the light projection pattern 203 and the test object, the light projection optical system 204 may not be required. In addition, the light projection optical system 204 may be used to set the light projection pattern 203 and the test object in a Scheimpflug optical system relationship. The measurement accuracy can be improved by focusing the entire surface of the light projection pattern 203 on the test object. Furthermore, when measuring the height of the test object, it is possible to prevent the measurement value from changing due to a local tilt of the test object.
[0016] The light receiving unit 205 may include a light receiving optical system 207 and a camera 208. Light reflected by the test object is incident on the camera 208 via the light receiving optical system 207. The camera 208 may include a light receiving element 206 having a plurality of pixels arranged two-dimensionally. However, depending on the type of the light source 202 and the distance between the test object and the camera 208, the light receiving optical system 207 may not be required. In addition, the test object and the light receiving element 206 may be in a Scheimpflug optical relationship using the light receiving optical system 207. The measurement accuracy can be improved by focusing the entire surface of the test object on the light receiving element 206. Furthermore, when measuring the height of the test object, it is possible to prevent the measurement value from changing due to the inclination of the test object.
[0017] Each component of the exposure apparatus 100, including the measurement unit 106, the stage 105, and the projection optical system 104, is connected to a control unit 107. The control unit 107 can be configured, for example, as a computer device including a processor (CPU) and a memory. The control unit 107 can store information such as the height and tilt of the substrate measured by the measurement unit 106, and can control the stage 105 by issuing a drive command to the stage 105.
[0018] An example of a height measurement method using the measurement unit 106 is shown. When a height variation occurs in the test object (substrate 108), the position of the image of the light projection pattern 203 projected onto the test object varies. When the position of the image of the light projection pattern 203 projected onto the test object varies, the position of the pattern image on the light receiving element 206 also varies. The control unit 107 detects the positional deviation of the pattern image on the light receiving element 206 to determine the height position of the substrate 108.
[0019] FIG. 3 shows an example of a light projection pattern 301 projected onto the substrate. A light projection pattern 203 from the light projection unit 201 is projected onto an exposure area 302, which is a precision inspection area of the substrate 108. A light projection pattern 301 corresponding to the light projection pattern 203 appears on the exposure area 302. As shown in FIG. 3, the light projection pattern 301 has an image of a plurality of slits. In order to precisely measure the height of the precision inspection area of the substrate 108, it is necessary to narrow the pattern interval 303 of the light projection pattern 301 as much as possible. When the light receiving element 206 is a two-dimensional light receiving element, height map information of the entire exposure area can be obtained at a measurement interval defined by the light projection pattern 301 on the substrate and the size of the light receiving element.
[0020] The measurement unit 106 measures the height position of the substrate 108 held by the stage 105 at a plurality of measurement points in the exposure area. Thereafter, the control unit 107 corrects the position of the stage 105 (height alignment) based on the measurement result by the measurement unit 106 so as to reduce the amount of deviation of the height position of the substrate 108 relative to the image plane of the projection optical system 104. The height alignment of the substrate during exposure is performed by controlling the height and tilt of the stage 105. For this reason, even if the height map in the exposure area is measured in detail, control is only performed on the primary planar components of the height and tilt directions.
[0021] Therefore, in this embodiment, the control unit 107 determines the number of necessary measurement points based on a previously obtained relationship between the number of measurement points and the correction residual due to the correction of the position of the stage 105 for each size of the exposure area, and determines the division number of the exposure area according to the determined number of necessary measurement points. FIG. 4 is a diagram showing the relationship between the number of measurement points of height measurement in the exposure area and the primary plane correction residual in the exposure area. FIG. 4 shows the relationship when the size (dimension) of the exposure area (shot area) is 26 mm×33 mm and the relationship when the size of the exposure area is 10 mm×10 mm. The required accuracy is determined from the focal depth of the projection lens. The number of measurement points is determined so that the primary plane correction residual falls below the required accuracy. According to FIG. 4, when the size of the exposure area is 26 mm×33 mm, the number of measurement points needs to be b points or more in order for the primary plane correction residual to fall below the required accuracy. Also, according to FIG. 4, when the size of the exposure area is 10 mm×10 mm, the number of measurement points needs to be a points or more, which is less than b points, in order for the primary plane correction residual to fall below the required accuracy.
[0022] In this embodiment, in order to capture features within the exposure area, the control unit 107 sets a plurality of measurement points such that one measurement point is assigned to each of a plurality of sub-areas obtained by dividing the exposure area based on the position or size of the exposure area. A method of dividing the exposure area in this embodiment will be described with reference to FIG. 5. As shown in FIG. 4 above, the number of measurement points A required for height position measurement is calculated from the size of the exposure area. Based on the calculated number of required measurement points A, the division number N is determined as follows: When the number of required measurement points A = 1, the number of divisions N = 1 (Figure 5(a)), When 1<number of required measurement points A≦4, the number of divisions N=4 (Fig. 5(b)), 4<number of required measurement points A≦9, the number of divisions N=9 (Fig. 5(c)), Similarly, (n-1) 2 < Number of required measurement points A ≦ n 2 When N=n, the number of divisions is 2 (Figure 5(d)) (where n is an equal fraction of the length and width). The control unit 107 divides the exposure area by the determined division number N, and sets a plurality of measurement points so that one measurement point is assigned to each of the obtained plurality (N) of sub-areas. In one example, the control unit 107 determines the center of the sub-area as the measurement position, as shown in FIG.
[0023] The control unit 107 performs height position measurements at the multiple measurement positions determined as described above, using the measurement unit 106. Based on the results of the measurements by the measurement unit 106, the control unit 107 corrects the position of the stage 105 so that the substrate surface is aligned with the focal position of the projection optical system 104, i.e., so that the amount of deviation of the substrate surface from the image plane of the projection optical system 104 is reduced. Thereafter, the control unit 107 performs exposure.
[0024] As described above, the control unit 107 divides the exposure area based on the size of the exposure area so that the characteristics within the exposure area can be captured, and performs height position measurement for each of the multiple sub-areas obtained by division. This makes it possible to reduce data transfer time and processing time without sacrificing measurement accuracy.
[0025] In this embodiment, a method of dividing the measurement area so that the measurement positions are arranged in a square is shown as an example, but the division method is not limited to this, and various methods of evenly arranging the measurement positions can be adopted.
[0026] Example 2 In the second embodiment, the control unit 107 divides the exposure area based on the position of the exposure area so that the characteristics in the exposure area can be captured, and performs height position measurement for each of the multiple sub-areas obtained by the division. In general, multiple chip pattern areas are formed on the mask. The number of chip pattern areas is arbitrary. The multiple chip pattern areas have the same pattern. One chip pattern area corresponds to one chip (die) to be manufactured. A normal shot area (exposure area) has a size in which all of the multiple chip pattern areas of the mask are projected. For example, consider a case where 4×2=8 chip pattern areas are formed on the mask. In this case, 4×2=8 chip areas are formed in one shot area of the substrate in accordance with the arrangement of the chip pattern areas of the mask, as shown in FIG. 7. In this case, the multiple sub-areas correspond to the multiple chip areas.
[0027] When multiple chip areas in one shot area are exposed at once, it is important to align the height between the chips in the shot area. In this embodiment, as shown in Figure 8, the center of each chip area is set as the measurement position. This allows the height alignment of each chip area in the shot area to be performed with high accuracy.
[0028] Example 3 In this embodiment, the exposure area is one area of interest among the multiple shot areas of the substrate 108. The multiple shot areas of the substrate 108 may include a full shot area located at the center of the substrate and a partial shot area located at the periphery of the substrate. The full shot area has a size that allows all of the pattern area of the mask 103 to be transferred. Thus, the full shot area has multiple chip areas corresponding to the multiple chip pattern areas of the mask 103. The partial shot area has a size that allows only a portion of the pattern area of the mask 103 to be transferred. In particular, the partial shot area has one or more chip areas corresponding to only a portion of the multiple chip pattern areas of the mask 103.
[0029] With reference to FIG. 9, an example of measuring the height position of a partial shot area located on the outer periphery of a substrate and exposing the area is shown. In the outer periphery of a substrate, the shape change may be larger than that of a full shot area due to the influence of roll-off, warping, sagging, etc. In addition, in the exposure of a partial shot area, since there is no test object in the area outside the substrate, the height position information of the area cannot be obtained. In this case, a region division method is set that can accurately capture the characteristics of a sudden height change in the partial shot area. Note that an increase in the number of divisions leads to an increase in the processing time. For this reason, in this embodiment, the measurement positions are determined according to the shape of the partial shot area so that the number of divisions does not change.
[0030] 10 shows an example of division of a partial shot area. FIG. 10(a) shows an example of division of a full shot area. The control unit 107 divides the full shot area into multiple equal parts (n equal parts) in both the vertical direction (first direction) and horizontal direction (second direction perpendicular to the first direction) (n=3 in the example of FIG. 10(a)). In this case, the number of divisions is N=n 2 On the other hand, for the partial shot region, the control unit 107 divides only the region in the substrate into n equal parts vertically and horizontally as shown in Fig. 10(b). As shown in Fig. 11, the center of each sub-region in the region in the substrate is determined as the measurement position.
[0031] FIG. 20 shows a flowchart of the exposure method according to this embodiment. In S1, the control unit 107 assigns measurement points to the exposure area. In this embodiment, a plurality of measurement points are set so that one measurement point is assigned to each of a plurality of sub-areas obtained by dividing the exposure area based on the position or size of the exposure area in the above-mentioned method. In S2, the control unit 107 measures the height position of the substrate 108 held by the stage 105 at a plurality of measurement points in the exposure area on the substrate. In S3, the control unit 107 corrects the position of the stage 105 based on the result of the measurement in S2 so that the amount of deviation of the height position of the substrate 108 relative to the image plane of the projection optical system 104 is reduced. After correcting the position of the stage, in S4, the control unit 107 exposes the exposure area.
[0032] <Second embodiment> 12 shows a flow chart of the exposure method in the second embodiment. In the above-mentioned first embodiment, an example in which the attention area is equally divided is shown. However, in the exposure area, fine unevenness and materials with different reflectances are mixed due to wiring patterns such as various circuit patterns. When obtaining height position information from the light projection pattern reflected from the test object, the shape of the reflected light changes significantly at a location where the unevenness changes sharply or at a location of a wiring pattern with high reflectance, and the measurement accuracy may decrease.
[0033] Therefore, in this embodiment, in S1201, the control unit 107 precisely measures the height position of the entire area of one predetermined sample shot area among the multiple shot areas in the substrate. Fig. 13 shows an example of a height distribution (height map) obtained in advance by measuring the height position in one sample shot area (sample area). According to the height map, it can be seen that unevenness (changes in height position) exists in the exposure area. The measurement accuracy when the height position is measured at a location where the height position changes abruptly is lower than the measurement accuracy when the height position is measured at a location where the height position is flat.
[0034] Therefore, in S1202, the control unit 107 determines the positions of a plurality of measurement points in the exposure area based on the height distribution obtained in S1201, as shown in FIG. 13. For example, the control unit 107 sets the positions of the measurement points in one exposure area where the amount of change in height position in the height distribution is smaller than a predetermined value. A specific example is shown with reference to FIG. 14. FIG. 14 shows an example of partial areas in one sample shot area where precise measurement of the height position is performed. The size of the partial area can be determined based on the minimum measurement unit defined by the measurement resolution of the light receiving unit 205. A height map is obtained from a set of height measurement values of each partial area. The control unit 107 can obtain differential values of the measurement values in adjacent partial areas and determine the partial areas where the differential value is equal to or smaller than a predetermined threshold value T1 as the measurement positions.
[0035] As another method, the control unit 107 acquires information on the measurement repeatability by performing a process for obtaining the height distribution in the sample region (a process for performing height position measurement in each partial region) multiple times as shown in FIG. 15. The control unit 107 determines the positions of multiple measurement points in the exposure region based on the acquired information on the measurement repeatability. For example, the control unit 107 determines a partial region with high measurement repeatability as the measurement position. The measurement repeatability is represented by a variation σ of multiple measurement values obtained by performing height position measurement multiple times. It can be said that the smaller the variation σ, the higher the measurement repeatability, i.e., the higher the measurement accuracy, and the larger the variation σ, the lower the measurement repeatability, i.e., the lower the measurement accuracy. Therefore, the control unit 107 can determine a partial region in which the variation σ is equal to or less than a predetermined threshold value T2 as the measurement position.
[0036] Generally, each exposure area on a substrate has roughly the same uneven shape. That is, each exposure area on a substrate has a similar uneven shape to the sample shot area. By utilizing such a tendency, in S1203, the control unit 107 performs height position measurement for the entire substrate surface (i.e., all exposure areas) at the measurement positions determined in S1202.
[0037] Thereafter, the control unit 107 aligns the height of the substrate based on the measurement value obtained in S1203 (S1204), and performs exposure (S1205).
[0038] In addition, when exposing the same circuit pattern, the height position profile in each exposure area will be similar, so S1201 to S1202 may be performed in advance for each circuit pattern, thereby making it possible to further reduce the effect on throughput.
[0039] <Third embodiment> In the above-mentioned first and second embodiments, an example was shown in which a pattern image obtained from an exposure area is divided and measurement positions are determined from the divided image. In the third embodiment, multiple measurement points are set by selecting a part of the distributed measurement points distributed over the entire exposure area.
[0040] 16 shows an example of distribution measurement points uniformly distributed over the entire surface of the exposure area. This can be realized, for example, by providing light receiving sensors at a plurality of predetermined positions uniformly distributed over the entire surface of the exposure area. Alternatively, it can be realized by performing height position measurements at the predetermined positions in the exposure area while scanning or stepping a number of times using a number of light receiving sensors that is smaller than the predetermined positions.
[0041] In order to reduce the processing time, the control unit 107 selects the minimum number of measurement points necessary to capture the characteristics in the exposure area from among the distributed measurement points uniformly distributed over the entire exposure area as shown in Fig. 16, and performs height position measurement. Fig. 17(a) shows that there are m x n measurement positions in the exposure area. Here, for example, the number of required measurement points obtained from the relationship shown in Fig. 4 is set to A. In this case, if m x n is more than 2 x A, the measurement points used for height position measurement are thinned out as shown in Fig. 17(b) or Fig. 17(c). This process is repeated as long as the number of measurement points is ultimately more than the number of required measurement points A, thereby realizing high-precision height position measurement with the minimum number of measurement positions necessary.
[0042] <Fourth embodiment> Consider an example in which a plurality of measurement positions are uniformly distributed over the entire surface of the exposure area as shown in Fig. 16, which has been explained in the third embodiment. Fig. 18 shows a flowchart of the exposure method in this case.
[0043] In S1801, the control unit 107 performs height position measurement multiple times at each distribution measurement point in a predetermined sample shot area among multiple exposure areas on a substrate. The control unit 107 calculates the variation σ of multiple measurement values obtained by performing the height position measurement multiple times as a value representing the measurement repeatability.
[0044] In S1802, the control unit 107 excludes measurement points whose variation σ is equal to or less than a predetermined threshold value from the measurement points to be used. That is, the control unit 107 determines that only measurement points whose variation σ exceeds a predetermined threshold value are to be used for height position measurement. Fig. 19 shows an example of the result of selecting only measurement points whose variation σ exceeds a predetermined threshold value as measurement points to be used for height position measurement.
[0045] In S1803, the control unit 107 performs height position measurement on the entire surface of the substrate (that is, all exposure regions) at the measurement positions determined in S1802.
[0046] Thereafter, the control unit 107 aligns the height of the substrate based on the measurement value obtained in S1803 (S1804), and performs exposure (S1805).
[0047] In the height position measurement method according to this embodiment, when measurement errors are likely to occur due to circuit patterns, the height position measurement can be performed with high accuracy by not using those measurement points, thereby enabling high-precision exposure.
[0048] <Embodiment of the article manufacturing method> The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as microdevices such as semiconductor devices and elements having a fine structure. The article manufacturing method of the present embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the above-mentioned exposure apparatus (a step of exposing the substrate), and a step of developing the substrate on which the latent image pattern has been formed in the step. Furthermore, the manufacturing method includes other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method of the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to conventional methods.
[0049] (Other embodiments) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) for implementing one or more of the functions.
[0050] The disclosure of the present specification includes at least the following exposure apparatus, exposure method, and article manufacturing method. (Item 1) 1. An exposure apparatus that projects a pattern of an original onto a substrate by a projection optical system to expose the substrate, comprising: a stage for holding and moving the substrate; a measurement unit that measures a height position of the substrate held by the stage at a plurality of measurement points in an exposure area; a control unit that controls the measurement unit and corrects a position of the stage based on a result of the measurement so that a deviation amount of the height position with respect to an image plane of the projection optical system is reduced; having an exposure apparatus characterized in that the control unit sets the multiple measurement points so that one measurement point is assigned to each of multiple sub-areas obtained by dividing the exposure area based on the position or size of the exposure area. (Item 2) The exposure apparatus described in item 1, characterized in that the control unit determines a required number of measurement points based on a previously obtained relationship between the number of measurement points and a correction residual due to the correction for each size of the exposure area, and determines a division number of the exposure area according to the determined required number of measurement points. (Item 3) 3. The exposure apparatus according to item 1 or 2, wherein the control unit sets a measurement point at the center of each of the plurality of sub-regions. (Item 4) 4. The exposure apparatus according to any one of items 1 to 3, wherein the plurality of sub-areas correspond to a plurality of chip areas. (Item 5) the exposure area is one of a plurality of shot areas of the substrate, the plurality of shot areas include a full shot area to which the entire pattern area of the original is transferred, and a partial shot area to which only a part of the pattern area of the original is transferred, The control unit divides the full shot region into n equal parts in a first direction and a second direction perpendicular to the first direction, and divides only a region within the substrate into n equal parts in the first direction and the second direction, for the partial shot region. 3. The exposure apparatus according to item 1 or 2. (Item 6) 6. The exposure apparatus according to item 5, wherein the control unit sets measurement points at the centers of the respective sub-regions for the full shot region, and sets measurement points at the centers of the respective sub-regions in the region of the substrate for the partial shot region. (Item 7) 7. The exposure apparatus according to any one of items 1 to 6, wherein the control unit sets the plurality of measurement points by selecting a portion of distributed measurement points that are uniformly distributed across the entire exposure area. (Item 8) 1. An exposure apparatus that projects a pattern of an original onto a substrate by a projection optical system to expose the substrate, comprising: a stage for holding and moving the substrate; a measurement unit that measures a height position of the substrate held by the stage at a plurality of measurement points in an exposure area; a control unit that controls the measurement unit and corrects a position of the stage based on a result of the measurement so that a deviation amount of the height position with respect to an image plane of the projection optical system is reduced; having The exposure apparatus according to claim 1, wherein the control unit determines positions of the plurality of measurement points in the exposure area based on a height distribution in a sample area obtained in advance. (Item 9) 9. The exposure apparatus according to item 8, wherein the control unit determines a position where an amount of change in height position in the height distribution is smaller than a predetermined value as the position of the measurement point. (Item 10) 9. The exposure apparatus according to item 8, wherein the control unit determines the positions of the plurality of measurement points in the exposure area based on information on measurement reproducibility obtained by performing a process of determining a height distribution in the sample area multiple times. (Item 11) 11. The exposure apparatus according to any one of items 8 to 10, wherein the control unit sets the plurality of measurement points by selecting a portion of distributed measurement points that are uniformly distributed across the entire exposure area. (Item 12) 1. An exposure method for projecting a pattern of an original onto a substrate by a projection optical system to expose the substrate, comprising: measuring a height position of the substrate held by a stage at a plurality of measurement points in an exposure area on the substrate; correcting the position of the stage based on a result of the measurement so as to reduce a deviation amount of the height position with respect to an image plane of the projection optical system; exposing the exposure area after correcting the position of the stage; having an exposure method, characterized in that the multiple measurement points are set so that one measurement point is assigned to each of multiple sub-areas obtained by dividing the exposure area based on a position or size of the exposure area. (Item 13) 1. An exposure method for projecting a pattern of an original onto a substrate by a projection optical system to expose the substrate, comprising: measuring a height position of the substrate held by a stage at a plurality of measurement points in an exposure area on the substrate; correcting the position of the stage based on a result of the measurement so as to reduce a deviation amount of the height position with respect to an image plane of the projection optical system; exposing the exposure area after correcting the position of the stage; having An exposure method, comprising: determining positions of the plurality of measurement points in the exposure area based on a height distribution in a sample area obtained in advance. (Item 14) Exposing a substrate according to the exposure method according to item 12 or 13; developing the exposed substrate; and producing an article from the developed substrate.
[0051] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]
[0052] 100: exposure apparatus, 101: light source, 102: illumination optical system, 103: mask, 104: projection optical system, 105: stage, 106: measurement unit
Claims
1. An exposure apparatus for projecting a pattern from an original plate onto a substrate using a projection optical system and exposing the substrate, A stage that holds and moves the substrate, A measurement unit that measures the height position of the substrate held by the stage at multiple measurement points in the exposure area, A control unit controls the measurement unit and corrects the position of the stage based on the measurement results so that the amount of the height position deviation with respect to the image plane of the projection optical system is reduced. It has, The exposure apparatus is characterized in that the control unit sets the plurality of measurement points in the exposure region based on information relating to the exposure region.
2. The exposure apparatus according to claim 1, characterized in that the control unit sets the plurality of measurement points in the exposure area such that one measurement point is assigned to each of the plurality of sub-regions obtained by dividing the exposure area based on the position or size of the exposure area.
3. The exposure apparatus according to claim 2, characterized in that the control unit determines the required number of measurement points based on a pre-obtained relationship between the number of measurement points and the correction residual due to the correction for each size of the exposure area, and determines the number of divisions of the exposure area according to the determined required number of measurement points.
4. The exposure apparatus according to claim 2, characterized in that the control unit sets a measurement point at the center of each of the plurality of sub-regions.
5. The exposure apparatus according to claim 2, characterized in that the plurality of sub-regions correspond to a plurality of chip regions.
6. The exposure region is one of a plurality of shot regions of the substrate, The plurality of shot regions include full shot regions in which the entire pattern region of the master plate is transferred, and partial shot regions in which only a portion of the pattern region of the master plate is transferred. The control unit sets different measurement points in the full shot region and the partial shot region. The exposure apparatus according to feature 2.
7. The exposure apparatus according to claim 6, characterized in that the control unit divides the full shot region into n equal parts in a first direction and a second direction perpendicular to the first direction, and divides only the region within the substrate into n equal parts in a first direction and a second direction, respectively, with respect to the partial shot region.
8. The exposure apparatus according to claim 6, characterized in that the control unit sets a measurement point at the center of each of the plurality of sub-regions for the full shot region, and sets a measurement point at the center of each of the plurality of sub-regions in the region within the substrate for the partial shot region.
9. The exposure apparatus according to claim 1, characterized in that the control unit sets the plurality of measurement points by selecting a portion of the distributed measurement points that are uniformly distributed over the entire exposure area.
10. The exposure apparatus according to claim 1, characterized in that the control unit determines the positions of the plurality of measurement points in the exposure area based on the height distribution in the sample area obtained in advance.
11. The exposure apparatus according to claim 10, characterized in that the control unit determines the position of the measurement point to be a position where the amount of change in the height position in the height distribution is smaller than a predetermined value.
12. The exposure apparatus according to claim 10, characterized in that the control unit determines the positions of the plurality of measurement points in the exposure area based on reproducibility information obtained by performing the process of determining the height distribution in the sample area multiple times.
13. The exposure apparatus according to claim 8, characterized in that the control unit sets the plurality of measurement points by selecting a portion of the distributed measurement points that are uniformly distributed over the entire exposure area.
14. The exposure apparatus according to claim 1, characterized in that the measurement unit projects a pattern over the entire area of the exposure region to measure the height position of the substrate.
15. An exposure method comprising projecting a pattern from an original plate onto a substrate using a projection optical system and exposing the substrate, A step of measuring the height position of the substrate held by the stage at multiple measurement points in the exposure area on the substrate, A step of correcting the position of the stage based on the measurement results so that the amount of the height position deviation with respect to the image plane of the projection optical system is reduced, After correcting the position of the stage, the process involves exposing the exposure area, It has, An exposure method characterized in that the plurality of measurement points in the exposure region are set based on information relating to the exposure region.
16. A step of exposing a substrate according to the exposure method described in claim 15, The process of developing the exposed substrate, A method for manufacturing an article, characterized by having a developed substrate and manufacturing an article from the developed substrate.