Measurement method, program, measuring device, lithography device, and method for manufacturing articles.

Abstract

To provide a technique advantageous for improving a measurement accuracy of treatment for measuring strain of a substrate by measuring a cycle pattern of a device region.SOLUTION: A measurement method for measuring strain of a substrate includes: an imaging step of imaging a plurality of partial regions of a pattern formed in a device region of the substrate; a measurement step of measuring a position of the pattern based on the images obtained in the imaging step; and a treatment step of calculating a cycle of the pattern based on the images obtained in the imaging step, and calculating a strain of a region on which the pattern of the substrate is formed based on the calculated cycle, and a measurement result obtained in the measurement step.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a measurement method, a program, a measurement device, a lithography device, and an article manufacturing method.

Background Art

[0002] In recent years, in exposure devices used for manufacturing semiconductor elements and the like, as the resolution line width is miniaturized, improvement in the overlay accuracy between a reticle and a substrate is required. Since the overlay accuracy is usually required to be about 1 / 5 of the resolution line width, as the miniaturization of semiconductor elements progresses, improvement in the overlay accuracy becomes increasingly important.

[0003] In order to improve the overlay accuracy, there is a technique of obtaining the shape of a shot region by measuring the positions of alignment marks arranged in a plurality in the shot region on a substrate and correcting the shape (for example, Patent Document 1).

[0004] However, alignment marks are arranged in the peripheral region of the semiconductor device region that should be corrected. Since the amount of distortion generated in the semiconductor manufacturing process is different between the device region and the peripheral region, even if the alignment marks arranged in the peripheral region are measured, the device region cannot be accurately measured correctly. In order to accurately measure the device region correctly, it is necessary to directly measure the device region. As a method of directly measuring the semiconductor device region, there is a method of registering a specific pattern in the device region and measuring the amount of misalignment using the registered pattern (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] However, when a periodic pattern is formed in the device region of a semiconductor, errors can occur due to the period of the periodic pattern, potentially leading to a decrease in the measurement accuracy of the periodic pattern.

[0007] The present invention provides an advantageous technique for improving the measurement accuracy of a process that measures substrate distortion by measuring the periodic pattern of a device region. [Means for solving the problem]

[0008] According to one aspect of the present invention, a measurement method for measuring the strain of a substrate is provided, comprising: an imaging step of imaging a plurality of partial regions of a pattern formed in a device region of the substrate; a measurement step of measuring the position of the pattern based on the images obtained in the imaging step; and a processing step of determining the period of the pattern based on the images obtained in the imaging step, and determining the strain of the region on the substrate in which the pattern is formed based on the determined period and the measurement results obtained in the measurement step. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an advantageous technique for improving the measurement accuracy of a process that measures the distortion of a substrate by measuring the periodic pattern of a device region. [Brief explanation of the drawing]

[0010] [Figure 1] A diagram showing the configuration of an exposure apparatus. [Figure 2] A diagram illustrating multiple shot regions on a substrate. [Figure 3] A diagram showing an example of the structure of the shot region. [Figure 4] A diagram showing the relationship between the periodic pattern formation region and the field of view of the imaging unit in the first embodiment. [Figure 5] A diagram illustrating a position measurement method based on periodic pattern images. [Figure 6] Figure showing the relationship between the substrate stage position and the measured values of the periodic pattern. [Figure 7] Flowchart showing the strain measurement method in the first embodiment. [Figure 8] Figure for explaining the method of measuring the period. [Figure 9] Graph showing the measured values of the periodic pattern with respect to the substrate stage position. [Figure 10] Graph of the measured values of the periodic pattern after the unwrapping process. [Figure 11] Graph of the measured values of the periodic pattern after the uncertainty value correction. [Figure 12] Graph of the measured values of the periodic pattern after removing the change in the measured values due to the drive of the substrate stage. [Figure 13] Figure showing a specific example of the measurement conditions. [Figure 14] Flowchart showing the strain measurement method in the second embodiment. [Figure 15] Figure for explaining the process of obtaining the difference in strain. [Figure 16] Figure showing the relationship between the periodic pattern formation region and the field of view of the imaging unit in the third embodiment. [Figure 17] Flowchart showing the strain measurement method in the fourth embodiment. [Figure 18] Figure showing an example of the imaging region included in the measurement field of view in the fourth embodiment.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant explanations are omitted.

[0012] <First Embodiment> The following describes an embodiment of a configuration in which a measuring device for measuring substrate distortion is incorporated into a lithography apparatus. The lithography apparatus is a substrate to This is a device for transferring patterns, and may be, for example, an exposure device, an imprint device, or an electron beam lithography device. Below, in order to provide a specific example, an embodiment will be described in which the lithography device is an exposure device.

[0013] Figure 1 shows the configuration of an exposure apparatus 1 as an example of a lithography apparatus. The exposure apparatus 1 is a lithography apparatus used in the lithography process, which is a manufacturing process for articles or devices such as semiconductor elements or liquid crystal display elements, to form a pattern on a substrate W. In this specification and drawings, directions are indicated in an XYZ coordinate system in which the horizontal plane is the XY plane. Generally, the substrate W to be exposed is placed on a substrate stage WS such that its surface is parallel to the horizontal plane (XY plane). Therefore, below, the directions that are orthogonal to each other in the plane along the substrate mounting surface of the substrate stage WS are defined as the X axis and Y axis, and the direction perpendicular to the X axis and Y axis is defined as the Z axis. Also, below, the directions parallel to the X axis, Y axis and Z axis in the XYZ coordinate system are referred to as the X direction, Y direction and Z direction, respectively.

[0014] Exposure apparatus 1 may be a scanning exposure apparatus (scanner). A scanning exposure apparatus is a type of exposure apparatus that exposes the pattern formed on the mask R onto the substrate W while moving the mask R, which is the master plate, and the substrate W in a synchronous manner in the scanning direction (for example, the Y direction). However, the present invention is not limited to a scanning exposure apparatus. Exposure apparatus 1 may also be an exposure apparatus (stepper) that exposes the pattern of the mask R onto the substrate W while the mask R and the substrate W are fixed together. Furthermore, the present invention can be applied not only to exposure apparatuses but also to batch exposure apparatuses for imprinting, substrate inspection apparatuses, and the like.

[0015] In this embodiment, the exposure apparatus 1 is a step-and-scan scanning exposure apparatus that scans and exposes a substrate W using slit light. The exposure apparatus 1 may include an illumination optical system IL, a mask stage RS that holds a mask R, a projection optical system PL, a substrate stage WS that holds the substrate W, an imaging unit AS, a detection unit D, a control unit MC, and a processing unit IP. The control unit MC may be composed of a computer (information processing device) having, for example, a processor such as a CPU (Central Processing Unit) and a storage unit such as memory. The control unit MC controls the exposure process of the substrate W by controlling each part of the exposure apparatus 1 according to a program stored in the storage unit. The program may also include a program that causes the processor to execute each step of the measurement method described later.

[0016] The illumination optical system IL illuminates a portion of the mask R with light emitted from a light source (not shown), such as an excimer laser. The mask R and the substrate W are held by the mask stage RS and the substrate stage WS, respectively, and are positioned optically conjugate via the projection optical system PL. The projection optical system PL has a predetermined projection magnification (e.g., 1 / 2x or 1 / 4x) and projects the pattern formed on the mask R onto the substrate.

[0017] The region of the substrate W onto which the pattern of the mask R is projected is called the shot region. Multiple shot regions, including shot regions SH1, SH2, and SH3, are arranged on the substrate W as shown in Figure 2. Hereafter, if any one of the multiple shot regions is being referred to as "shot region SH" without using a subscript, and it is not necessary to specify which of the shot regions SH1, SH2, or SH3 it is, it will be referred to as "shot region SH".

[0018] The mask stage RS and substrate stage WS are configured to move perpendicular to the optical axis of the projection optical system PL, and are scanned relatively at a speed ratio corresponding to the projection magnification of the projection optical system PL, while synchronizing with each other. This allows the shot area SH to be scanned on the substrate, transferring the pattern of the mask R to the shot area SH on the substrate. By sequentially repeating this scanning exposure for each of the multiple shot areas on the substrate, the exposure process on a single substrate W can be completed.

[0019] The detection unit D includes, for example, a laser interferometer and detects the position of the substrate stage WS. The laser interferometer included in the detection unit D, for example, irradiates a laser beam toward a reflector M provided on the substrate stage WS, and detects the displacement of the substrate stage WS from a reference position based on the laser beam reflected by the reflector M. As a result, the detection unit D can obtain the current position of the substrate stage WS based on this displacement. Here, the detection unit D uses a laser interferometer to detect the position of the substrate stage WS, but is not limited to that, and may use, for example, an encoder.

[0020] The substrate stage WS holds the substrate W via a substrate chuck (not shown) that chucks the substrate W. The substrate stage WS may be driven by a substrate drive mechanism (not shown). The substrate drive mechanism is a positioning mechanism that positions the substrate W based on the measurement results of the measuring device of this embodiment. The substrate drive mechanism includes a linear motor or the like, and can move the substrate W held by the substrate stage WS by driving the substrate stage WS in the X, Y, Z directions and rotational directions around each axis.

[0021] The imaging unit AS may include an illumination unit (not shown). Light from the illumination unit illuminates the substrate W, and the reflected light enters the imaging unit AS. The imaging unit AS captures the incident light with an image sensor and generates an image signal. The image signal is transferred to the processing unit IP.

[0022] The processing unit IP performs mark position measurement processing using methods such as template matching or phase-limited correlation based on the image acquired by the imaging unit AS. The processing unit IP may be a computer device including a CPU and memory. The processing unit IP and the control unit MC may be configured as separate devices, or the functions of the processing unit IP and the control unit MC may be realized by a single computer device.

[0023] Figure 3 shows an example of the structure of a shot region SH. The shot region SH has a device region DD where the device pattern is formed and a peripheral region SL surrounding the device region DD. Multiple alignment marks are placed in the shot region SH. These alignment marks are generally placed at the four corners of the shot region SH. In the example in Figure 3, alignment marks AM1 to AM4 are placed at the four corners of the peripheral region SL within the shot region SH. On the other hand, the device region DD has a periodic pattern formation region CE 11 ~CE 32 These are arranged. There is a difference in pattern density between the device region DD and the peripheral region SL, resulting in differences in the way distortion occurs due to the semiconductor manufacturing process. Therefore, it is difficult to measure the distortion of the device region DD with high precision when measuring the shape of the shot region SH using alignment marks AM1 to AM4.

[0024] The relationship between the periodic pattern formation region and the measurement field of view of the imaging unit AS will be explained with reference to Figures 4(a) and (b). Figure 4(a) shows the distortion-free, ideal periodic pattern formation region CE. 32 This is shown. Periodic pattern formation region CE 32 The pattern formed is a line-and-space periodic pattern with a periodic structure in the Y direction. The period of the line-and-space pattern is P. Although this document describes the measurement of a line-and-space periodic pattern with a periodic structure in the Y direction, the technology of this disclosure is also applicable to periodic patterns with a periodic structure in the X direction, or periodic patterns with periodic structures in both the X and Y directions. Furthermore, the periodic pattern formation region CE may be understood as an already formed base pattern.

[0025] However, in reality, the substrate has distortion, and therefore the period of the pattern is not constant P. Figure 4(b) shows the distorted periodic pattern formation region CE. 33 This is shown.

[0026] One method for measuring the distortion of a periodic pattern is to image the entire area of ​​the periodic pattern at once and obtain the distortion distribution by calculating the period P of the periodic pattern. However, this method cannot be used if the measurement field of the imaging unit AS is narrow relative to the periodic pattern formation area CE. Therefore, it is necessary to measure the position of the pattern based on periodic pattern images obtained by imaging multiple partial areas of the pattern formed on the device area of ​​the substrate. Figure 4(b) shows an example of multiple measurement areas I1, I2, I3, and I4 as multiple partial areas. In Figure 4(b), the multiple measurement areas I1 to I4 are set to be aligned at a predetermined pitch (relative drive amount Ys between the imaging unit AS and the periodic pattern formation area CE) in a direction parallel to the periodic direction (Y direction) of the pattern.

[0027] Referring to Figure 5, a position measurement method based on a periodic pattern image will be explained. Figures 5(a) to (c) show examples of position measurement of a line-and-space periodic pattern by template matching. Figure 5(a) shows a template image 2 with a periodic pattern and a signal intensity waveform 3 acquired by the imaging unit AS. Figure 5(b) shows the acquired image 4 and signal intensity waveform 5 when the relative position between the imaging unit AS and the periodic pattern formation region CE is shifted by dy. By measuring the position of the periodic pattern and comparing the template image 2 (signal intensity waveform 3) and the acquired image 4 (signal intensity waveform 5), the amount of deviation from the template dy (phase difference) can be determined as a measured value. Figure 5(c) shows the acquired image 6 and signal intensity waveform 7 when the relative position between the imaging unit AS and the periodic pattern formation region CE is shifted by P, which corresponds to one period of the periodic pattern. When the change in the relative position between the imaging unit AS and the periodic pattern formation region CE is an integer multiple of P, the acquired image 6 (signal intensity waveform 7) and the template image 2 (signal intensity waveform 3) become the same image with a pitch shift.

[0028] Figure 6 shows the relationship between the relative position of the imaging unit AS and the periodic pattern formation region CE and the measured value dy of the periodic pattern. In Figure 6, the substrate stage position is plotted on the horizontal axis to represent the relative position of the imaging unit AS and the periodic pattern formation region CE. The vertical axis represents the measured value dy of the periodic pattern. As shown in Figure 6, the measured value dy is folded within the range of ±P / 2. Therefore, the substrate stage position WS n (where n is an integer greater than or equal to 1), the measured value becomes dy1 + n × P, resulting in an integer multiple of uncertainty (= n × P). This uncertainty can become the measurement error of the strain in the periodic pattern formation region.

[0029] Therefore, in this embodiment, the position information of the substrate stage WS acquired by the detection unit D and the period P obtained from the captured periodic pattern image are used to correct multiple position measurement results of the periodic pattern. By correcting the uncertain values, the distortion within the periodic pattern formation region can be measured with high accuracy.

[0030] Figure 7 is a flowchart showing the strain measurement process within the periodic pattern formation region. In S101, the control unit MC transports the substrate W to be processed from the substrate transport device (not shown) into the exposure apparatus 1. The substrate W is placed and held on the substrate stage WS. In S102, the control unit MC adjusts the relative position of the substrate W and the imaging unit AS using the substrate stage WS in order to image the periodic pattern of the object to be measured. In S103, the processing unit IP registers the periodic pattern image of the periodic pattern formation region CE as a mark and measures the period P based on that periodic pattern image. Note that S103 can be omitted if the registration of the periodic pattern image and the measurement of the period P of the periodic pattern are performed in advance.

[0031] In S104, the control unit MC sets the measurement conditions. The measurement conditions may include the shot region SH on the substrate W to be measured, the periodic pattern formation region CE, the number of measurement regions within the periodic pattern formation region (number of sub-regions), the relative drive amount Ys between the imaging unit AS and the periodic pattern formation region CE, etc. Figure 4(b) shows the shot region SH1 and the periodic pattern formation region CE. 33 The diagram shows the case where measurement areas I1 to I4 and relative drive amount Ys are set as measurement conditions. Here, the area captured by the imaging unit AS is the measurement area I1 to I4.

[0032] In S105, the control unit MC adjusts the relative position of the substrate W and the imaging unit AS using the substrate stage WS in order to image the measurement areas I1 to I4 (adjustment step). Then, one sub-area (for example, measurement area I1) is imaged by the imaging unit AS (imaging step). In S106, the processing unit IP measures the position of the periodic pattern based on the periodic pattern image obtained by imaging by the imaging unit AS (measurement step). This measurement step outputs the phase difference of the signal intensity waveforms obtained from each image of multiple sub-regions as the measured value. In S107, the control unit MC determines whether position measurement has been completed in all measurement areas (sample positions) on the substrate W set in S104. If there are any measurement areas that have not been measured (NO in S107), the process returns to S104. As a result, the adjustment process, imaging process, and measurement process are performed for each of the multiple sub-regions. If measurement has been completed in all measurement areas on the substrate W (YES in S107), the process proceeds to S108. In S108, the control unit MC calculates the amount of distortion in the periodic pattern formation region. S108 is a processing step in which the period of the pattern is determined based on the image obtained in the imaging step, and the distortion of the periodic pattern formation region on the substrate W is determined based on the determined period and the measurement results obtained in the measurement step.

[0033] Figure 8(a) shows the signal intensity waveform of a periodic pattern image obtained by imaging with the imaging unit AS. The horizontal axis indicates the position in the Y direction. In the processing step, the period of the pattern is determined based on the signal intensity waveform obtained from the periodic pattern image. For example, since the periodic pattern image contains one or more periods, multiple periods (e.g., P1 to P5) may be determined from the signal intensity, and their average value may be taken as the period P of the periodic pattern. Alternatively, the period may be determined after differentiating the signal intensity of the periodic pattern image. Or, in the processing step, the period of the pattern may be determined based on the relationship between the position of the substrate stage WS obtained by detection by the detection unit D and the measured value dy. Figure 8(b) shows the measured value dy of the periodic pattern with respect to the substrate stage position. Since the measured value is folded within the range of the period P of the periodic pattern, the periods P6 and P7 of the periodic pattern can be determined from the position information of the substrate stage WS acquired by the detection unit D. Similarly to the above, the periods may be determined in multiple regions, and their average value may be taken as the period P of the periodic pattern.

[0034] In the processing step, the measurement results obtained in the measurement step are corrected based on the position information of the substrate stage WS when imaging each of the multiple sub-regions in the imaging step, and the determined period. Based on the corrected measurement results, the distortion of the pattern formation region can be determined. The position information of the substrate stage WS is obtained from the detection unit D each time the relative position is adjusted in the adjustment step. A specific example of the process for determining the distortion of the pattern formation region is shown below.

[0035] Figure 9 is a graph showing the measured values ​​of the periodic pattern at multiple positions on the substrate stage, obtained in the processing steps S104 to S107. This shows the relationship between the position information of the substrate stage WS obtained by the detection unit D and the measured values. As described above, the measured values ​​of this periodic pattern are folded (wrapped) within the range of ±P / 2. Therefore, discontinuities in the measured values ​​(folding points, cusps, singularities) occur due to the folding of the measured values. Here, the occurrence of discontinuities in the measured values ​​may also include discontinuities in the slope of the relationship (graph) between the position information and the measured values. It may also include the fact that the measured values ​​are not differentiable at the discontinuities. Therefore, the processing step (S108) may include an unwrap process that continuousizes the discontinuities in the measured values ​​using the period P obtained in S103 for the measurement results in Figure 9.

[0036] Figure 10 shows the measured values ​​of the periodic pattern after unwrapping the measured values ​​of the periodic pattern shown in Figure 9. Since the measured values ​​of the periodic pattern include an uncertain value n × P component for each relative drive, it is necessary to correct the uncertain value using the position information of the substrate stage WS acquired by the detection unit D and the period P. In this embodiment, the value of n can be determined from the position information of the substrate stage WS acquired by the detection unit D. Therefore, the processing step (S108) may further include a step of correcting the unwrapped measured values ​​based on the position information of the substrate stage WS obtained by detection by the detection unit D and the determined period P.

[0037] Figure 11 shows the measured values ​​of the periodic pattern after correcting for uncertain values. Here, the correction of uncertain values ​​can only be performed if the condition that "the distortion of the periodic pattern that occurs during the relative drive amount Ys is less than the period P / 2" is met. Therefore, the relative drive amount Ys set in S104 may be set based on the strain distribution obtained in advance on a substrate W manufactured in the same process, or on the trend of measurement results from two or more points. In addition, the relative drive amount may not be constant, but may be set to a drive amount that fluctuates according to the strain distribution.

[0038] The processing step (S108) may further include a step of removing the change in the measured value due to the driving of the substrate stage WS from the unwrapped and corrected measured value, using the position information of the substrate stage WS obtained by detection by the detection unit D. This step makes it possible to determine the distortion of the periodic pattern formation region. Figure 12 shows the result of removing the change in the measured value due to the driving of the substrate stage WS from the measurement results shown in Figure 11, using the position information of the substrate stage WS acquired by the detection unit D. The amount of change in the measured value shown in Figure 12 corresponds to the distortion of the periodic pattern formation region.

[0039] As described above, in this embodiment, the position of the periodic pattern is measured based on periodic pattern images captured at multiple positions within the periodic pattern formation region. By correcting the measurement results based on the position information of the substrate stage WS acquired by the detection unit D and the period P obtained from the captured periodic pattern images, the distortion within the periodic pattern formation region can be measured.

[0040] During the exposure process, based on the measured distortion, it becomes possible to correct the pattern image of the mask M so that the overlapping error between the background pattern of the substrate W and the pattern image of the mask M falls within an acceptable range.

[0041] Referring to Figure 13, the setting of the measurement conditions shown in S104 will be explained with reference to three examples.

[0042] (Example 1) As Example 1, the conditions with a step width of 0.5 μm (P / 2 or less) are shown. In Figure 13, the step width Ys, the number of measurement areas, and the uncertainty value n×P generated in one relative drive are shown, with the measurement direction dimension of the periodic pattern formation region CE being 3 mm and the period P of the periodic pattern being 1500 nm. The number of measurement areas to measure the entire periodic pattern formation region CE is 6000 points, and the uncertainty value generated in one relative drive is 0. Therefore, it is possible to measure strain by performing unwrapping of the measurement results and removing the change in measurement values ​​due to the substrate stage WS drive. Correction becomes easier, but the number of measurement areas becomes enormous, and the measurement time per run becomes long.

[0043] (Example 2) As Example 2, we show the conditions with a step width of 200 μm (P / 2 or less). The number of measurement points for measuring the entire periodic pattern formation region CE is 15, and the uncertainty value generated in one relative drive is 199.8 μm. Therefore, by performing unwrapping of the measurement results, correction of uncertainty values, and removal of measurement value changes due to substrate stage WS drive, it is possible to measure strain. In this way, by correcting the measurement values ​​using a wide step width, the strain measurement time is shortened.

[0044] (Example 3) As Example 3, we show the condition with a step width of 150 μm (an integer multiple of P / 2). The number of measurement points for measuring the entire periodic pattern formation region CE is 20. Here, since the step width is an integer multiple of P / 2, no relative positional shift of the periodic pattern occurs due to the driving of the substrate stage WS. Therefore, under these conditions, it is possible to measure the strain by performing only the unwrapping process of the measurement results.

[0045] <Second Embodiment> A second embodiment will now be described. Note that the configuration of the exposure apparatus according to the second embodiment may follow that of the first embodiment, except for matters mentioned below.

[0046] In the first embodiment, the measurement results of the periodic pattern formation region were corrected using the substrate stage position and the periodic pattern period P, and the distortion was measured. In contrast, in the second embodiment, a measurement process including an imaging step, a measurement step, and a processing step was performed for each of the multiple shot regions of the substrate W, and the difference in distortion with respect to the reference shot region was determined.

[0047] Figure 14 is a flowchart showing the method for measuring the difference in strain in the periodic pattern formation region. Here, the measurement of the period P of the periodic pattern in S103, which was performed in the first embodiment, is unnecessary.

[0048] In S104, the control unit MC selects the measurement conditions. Here, as an example, consider the case where the three shot regions SH1, SH2, and SH3 shown in Figure 2 are selected.

[0049] In S109, the control unit MC calculates the strain change in the periodic pattern formation region. Figure 15 shows the measurement results for each of the three shot regions SH1 to SH3, and the change in the measured values ​​of shot regions SH2 and SH3 relative to shot region SH1. Since the measurement conditions are the same for the three shot regions SH1 to SH3, the difference in strain can be obtained even with folded measurement results.

[0050] Here, the measured value in the periodic pattern formation region of the reference shot area may be a measured value previously obtained from a substrate W manufactured in the same process. Also, the strain in the periodic pattern formation region of the reference shot area may be a value previously inspected by another inspection device. Furthermore, this embodiment may be applied to a process monitor that determines an abnormality when the change in strain from the reference shot area exceeds a predetermined threshold. Such a process monitor can, for example, detect strain in the substrate W that occurs in well-known semiconductor manufacturing processes (oxidation, film deposition, evaporation, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.) and determine an abnormality.

[0051] According to this embodiment, it is possible to measure the difference in strain in the periodic pattern formation region from multiple measurement results obtained in different regions.

[0052] <Third Embodiment> A third embodiment will now be described. The configuration of the exposure apparatus according to the third embodiment may follow that of the first embodiment, except for matters mentioned below.

[0053] In the first embodiment, the multiple measurement regions I1 to I4, which are multiple sub-regions, were aligned in a direction parallel to the periodic direction (Y direction) of the periodic pattern. Therefore, the relative driving direction between the imaging unit AS and the periodic pattern formation region CE was the periodic direction of the periodic pattern. As a result, the measured values ​​were folded into a range of ±P / 2, resulting in uncertain values ​​and a decrease in measurement accuracy. In contrast, in the third embodiment, the multiple measurement regions, which are multiple sub-regions, are set to be aligned in a direction intersecting the periodic direction of the periodic pattern. That is, the relative driving direction between the imaging unit AS and the periodic pattern formation region CE is set to a non-periodic direction (e.g., the X direction) that intersects the periodic direction of the periodic pattern. Therefore, there is no folding of measured values ​​or uncertain values, and the measurement result directly represents the amount of distortion in the periodic pattern formation region.

[0054] The flow for measuring the strain change in the periodic pattern formation region in this embodiment is the same as in the first embodiment (Figure 7). However, the measurement of the period P of the periodic pattern in S103, which was performed in the first embodiment, is unnecessary.

[0055] In S104, the control unit MC sets the measurement conditions. Figure 16 shows a specific example of the settings in the third embodiment. Shot region SH1, periodic pattern formation region CE 22 Selecting this option sets the number of measurement areas to 4 and the relative drive amount Xs. As a result, measurements are performed on multiple measurement areas I5 to I8. When measuring strain in a non-periodic direction, no displacement of the periodic pattern due to the board stage WS drive occurs.

[0056] According to this embodiment, by measuring the position based on periodic pattern images captured at multiple positions within the periodic pattern formation region, it is possible to measure the distortion in the non-periodic direction within the periodic pattern formation region.

[0057] <Fourth Embodiment> A fourth embodiment will now be described. Note that the configuration of the exposure apparatus according to the fourth embodiment may follow that of the first embodiment, except for matters mentioned below.

[0058] In the first embodiment, the measurement of the initial measurement area I1 is not aligned with sufficient precision, which can result in uncertain values. Therefore, the change in the measured value was measured as strain, with the measurement area I1 as the reference. In contrast, in the fourth embodiment, before starting the measurement of the strain of the substrate W, the relative position of the imaging unit AS and the substrate W is aligned based on alignment marks formed around the device area DD. This prior alignment makes it possible to measure the measurement area I1 as an absolute position.

[0059] Figure 17 is a flowchart showing the strain change measurement in the fourth embodiment. In Figure 17, S110 is added between the substrate loading in S101 and the substrate transport in S102. In S110, the control unit MC performs alignment measurement. For example, the control unit MC adjusts the relative position of the substrate W and the imaging unit AS using the substrate stage WS so that the alignment marks AM placed in the peripheral region SL can be measured, and then the imaging unit AS captures images of the alignment marks AM.

[0060] As an example of alignment measurement, Figure 18 shows an image of the periodic pattern configuration area of ​​the device region and the alignment mark AM located in the peripheral region SL being captured in the same field of view. Here, the alignment mark AM may be any circuit pattern around the device. The measurement field of view 8 includes an imaging area 9 that includes the alignment mark AM located in the peripheral region SL, and an imaging area 10 that includes the periodic pattern. The processing unit IP uses the imaging area 9 of the measurement field of view 8 for alignment measurement and the imaging area 10 of the measurement field of view 8 for position measurement of the periodic pattern.

[0061] According to this embodiment, by aligning with alignment marks and measuring the position based on periodic pattern images captured at multiple positions within the periodic pattern formation region, the distortion at the absolute position within the periodic pattern formation region can be measured.

[0062] <Embodiment of Article Manufacturing Method> A method for manufacturing articles using the lithography apparatus described above will be explained exemplified. The method is suitable for manufacturing articles such as devices (semiconductor elements, magnetic storage media, liquid crystal display elements, etc.). The manufacturing method includes the steps of exposing a substrate coated with a photosensitive agent (forming a pattern on the substrate) using an exposure apparatus EXA, and developing the exposed substrate (processing the substrate). The manufacturing method may also include other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The method for manufacturing articles in this embodiment is advantageous compared to conventional methods in at least one of the performance, quality, productivity, and production cost of the articles. The method for manufacturing articles described above may also be carried out using lithography apparatus such as an imprint apparatus or a drawing apparatus.

[0063] <Other Embodiments> The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by a process in which one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0064] The disclosures herein include at least the following technologies: (Item 1) A measurement method for measuring the distortion of a circuit board, An imaging step of imaging multiple sub-regions of a pattern formed on the device region of the substrate, A measurement step in which the position of the pattern is measured based on the image obtained in the imaging step, A processing step which involves determining the period of the pattern based on the image obtained in the imaging step, and determining the distortion of the region on the substrate where the pattern is formed based on the determined period and the measurement results obtained in the measurement step, A measurement method characterized by having the following features. (Item 2) The process includes an adjustment step for adjusting the relative position between the imaging unit used in the imaging step and the substrate, After the adjustment step, the imaging step captures an image of one subregion. In the measurement step, the position of the pattern is measured based on the image of the one subregion. For each of the plurality of subregions, the adjustment step, the imaging step, and the measurement step are performed. The measurement method described in item 1, characterized by the following: (Item 3) In the processing step, the measurement results obtained in the measurement step are corrected based on the position information of the stage holding the substrate when imaging each of the plurality of partial regions in the imaging step and the determined period, and the distortion of the region on the substrate where the pattern is formed is determined based on the corrected measurement results. The measurement method described in item 2, characterized by the following: (Item 4) The measurement method according to item 3, characterized in that the information on the position of the stage is obtained from a detection unit that detects the position of the stage each time the relative position is adjusted in the adjustment step. (Item 5) The measurement method according to any one of items 1 to 4, characterized in that the processing step involves determining the period of the pattern based on the signal intensity waveform obtained from the image. (Item 6) The measurement method according to item 4, characterized in that the measurement step outputs the phase difference of the signal intensity waveforms obtained from each image of the plurality of subregions as a measured value. (Item 7) The measurement method according to item 6, characterized in that the processing step involves determining the period of the pattern based on the relationship between the position of the stage obtained by detection by the detection unit and the measured value. (Item 8) The aforementioned processing step is: A step of performing an unwrapping process to make the discontinuities in the measured values ​​in the aforementioned relationship continuous, A step of correcting the unwrapped measured value based on the information of the stage position obtained by detection by the detection unit and the determined period, A step of determining the distortion of the region in which the pattern is formed by using the information of the stage position obtained by detection by the detection unit, and removing the change in the measured value due to the driving of the stage from the corrected measured value, The measurement method according to item 7, characterized by including the following: (Item 9) The measurement method according to any one of items 1 to 8, characterized in that the plurality of subregions are arranged in a direction parallel to the periodic direction of the pattern. (Item 10) In each of the multiple shot regions of the substrate, a measurement process including the imaging step, the measurement step, and the processing step is performed. To calculate the difference in distortion relative to the reference shot area, A measurement method according to any one of items 1 to 9, characterized by the above. (Item 11) The measurement method according to any one of items 1 to 8, characterized in that the plurality of subregions are arranged in a direction intersecting the periodic direction of the pattern. (Item 12) The measurement method according to any one of items 1 to 11, further comprising the step of performing relative alignment between the imaging unit and the substrate based on marks formed around the device area before starting to measure the distortion of the substrate. (Item 13) A program that causes a computer to perform each step of the measurement method described in one of items 1 through 12. (Item 14) A measuring device comprising an imaging unit and a control unit for measuring the strain of a substrate, The control unit, The imaging unit is controlled to image multiple partial regions of a pattern formed on the device region of the substrate. Based on the image obtained from the aforementioned imaging, the position of the pattern is measured. The system is configured to determine the period of the pattern based on the image obtained by the aforementioned imaging, and to determine the distortion of the region on the substrate where the pattern is formed based on the determined period and the measurement results. A measuring device characterized by the following features. (Item 15) Lithography apparatus, A measuring device as described in item 14, configured to measure the distortion of a circuit board, The system includes a positioning mechanism that positions the substrate based on the strain of the substrate measured using the measuring device, A lithography apparatus characterized by being configured to transfer the pattern of the aforementioned substrate. (Item 16) The process of transferring a pattern onto a substrate using the lithography apparatus described in item 15, A step of obtaining an article by processing the substrate onto which the pattern has been transferred, A method for manufacturing articles, characterized by including the following:

[0065] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0066] 1: Exposure apparatus, R: Mask, W: Substrate, IL: Illumination optics, WS: Substrate stage, PL: Projection optics, D: Detection unit, MC: Control unit, IP: Processing unit

Claims

1. A measurement method for measuring the distortion of a circuit board, An imaging step of imaging multiple sub-regions of a pattern formed on the device region of the substrate, A measurement step in which the position of the pattern is measured based on the image obtained in the imaging step, A processing step which involves determining the period of the pattern based on the image obtained in the imaging step, and determining the distortion of the region on the substrate where the pattern is formed based on the determined period and the measurement results obtained in the measurement step, A measurement method characterized by having the following features.

2. The process includes an adjustment step for adjusting the relative position between the imaging unit used in the imaging step and the substrate, After the adjustment step, the imaging step captures an image of one sub-region. In the measurement step, the position of the pattern is measured based on the image of the one subregion. For each of the plurality of subregions, the adjustment step, the imaging step, and the measurement step are performed. The measurement method according to feature 1.

3. In the processing step, the measurement results obtained in the measurement step are corrected based on the position information of the stage holding the substrate when imaging each of the plurality of partial regions in the imaging step and the determined period, and the distortion of the region on the substrate in which the pattern is formed is determined based on the corrected measurement results. The measurement method according to feature 2.

4. The measurement method according to claim 3, characterized in that the information on the position of the stage is obtained from a detection unit that detects the position of the stage each time the relative position is adjusted in the adjustment step.

5. The measurement method according to claim 1, characterized in that the processing step involves determining the period of the pattern based on the signal intensity waveform obtained from the image.

6. The measurement method according to claim 4, characterized in that the measurement step outputs the phase difference of the signal intensity waveforms obtained from each image of the plurality of subregions as a measured value.

7. The measurement method according to claim 6, characterized in that the processing step involves determining the period of the pattern based on the relationship between the position of the stage obtained by detection by the detection unit and the measured value.

8. The aforementioned processing step is: A step of performing an unwrapping process to make the discontinuities in the measured values ​​in the aforementioned relationship continuous, A step of correcting the unwrapped measured value based on the information of the stage position obtained by detection by the detection unit and the determined period, A step of determining the distortion of the region in which the pattern is formed by using the information of the stage position obtained by detection by the detection unit, and removing the change in the measured value due to the driving of the stage from the corrected measured value, The measurement method according to claim 7, characterized by including the following:

9. The measurement method according to claim 1, characterized in that the plurality of subregions are arranged in a direction parallel to the periodic direction of the pattern.

10. In each of the multiple shot regions of the substrate, a measurement process including the imaging step, the measurement step, and the processing step is performed. To calculate the difference in distortion relative to the reference shot area, The measurement method according to feature 1.

11. The measurement method according to claim 1, characterized in that the plurality of subregions are arranged in a direction intersecting the periodic direction of the pattern.

12. The measurement method according to claim 1, further comprising the step of performing relative alignment between the imaging unit and the substrate based on marks formed around the device region before starting to measure the distortion of the substrate.

13. A program for causing a computer to perform each step of the measurement method described in any one of claims 1 to 12.

14. A measuring device comprising an imaging unit and a control unit for measuring the strain of a substrate, The control unit, The imaging unit is controlled to image multiple partial regions of a pattern formed on the device region of the substrate. Based on the image obtained from the aforementioned imaging, the position of the pattern is measured. The system is configured to determine the period of the pattern based on the image obtained by the aforementioned imaging, and to determine the distortion of the region on the substrate where the pattern is formed based on the determined period and the measurement results. A measuring device characterized by the following features.

15. A lithography device, A measuring device according to claim 14, configured to measure the distortion of a substrate, The system includes a positioning mechanism that positions the substrate based on the strain of the substrate measured using the measuring device, A lithography apparatus characterized by being configured to transfer a pattern onto the aforementioned substrate.

16. A step of transferring a pattern onto a substrate using the lithography apparatus described in claim 15, A step of obtaining an article by processing the substrate onto which the pattern has been transferred, A method for manufacturing articles, characterized by including the following:

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