Determination method, information processing device, exposure apparatus, and method for manufacturing articles

Abstract

This provides a technique that is advantageous for determining a threshold value for assessing the validity of baseline measurements. [Solution] A determination method for determining a judgment value for determining the validity of a baseline measurement value, which represents the distance between the optical axis of a first scope that detects marks via a projection optical system that projects light from a master plate onto a substrate, and the optical axis of a second scope that detects marks without using a projection optical system, comprising: a first step of obtaining a reference baseline from the detection results of a first number of times by the first scope and the second scope; a second step of obtaining a baseline measurement value from the detection results of a second number of times which is less than the first number of times by the first scope and the second scope; and a third step of determining a judgment value to be used after obtaining the baseline measurement value, based on the reference baseline obtained in the first step and the measurement value of the previous baseline obtained in the second step.

Description

[Technical Field]

[0001] The present invention relates to a determination method, an information processing device, an exposure apparatus, and a method for manufacturing articles. [Background technology]

[0002] One type of lithography equipment used in the manufacturing process of devices such as semiconductor elements and liquid crystal panels is an exposure device that transfers the pattern from a master plate onto a substrate. In order to transfer the pattern from the master plate onto the substrate with high precision, it is necessary to align the master plate and the substrate. Therefore, before exposing the substrate, alignment measurement is performed by detecting (imaging) alignment marks provided on both the master plate and the substrate and measuring the position of the alignment marks.

[0003] There are broadly two methods for measuring alignment. One is a measurement method called the through-the-mirror method, which detects the alignment marks on both the master plate and the substrate via a projection optical system. The other is a measurement method called the off-axis method, which detects only the alignment marks on the substrate without using a projection optical system. Generally, exposure equipment is equipped with alignment scopes for each of these methods, and they are operated according to their respective roles.

[0004] In order to perform alignment measurement using the off-axis method, alignment measurement using the through-mirror method must be performed beforehand. This is because a baseline is required, which is the relative positional relationship between the detection position obtained from the through-mirror alignment measurement (the projection position of the pattern on the original plate) and the detection position obtained from the off-axis alignment measurement. Specifically, in off-axis alignment measurement, it is necessary to use the baseline to correct the detection position obtained from the alignment measurement. The baseline can be measured with high accuracy by performing mark detection using both the through-mirror method and the off-axis method multiple times.

[0005] On the other hand, in exposure equipment, it is known that the baseline fluctuates and is not constant due to the influence of heat generated by exposure light and the driving of the stage, which cause time-dependent errors in the relationship between the original plate coordinate system and the substrate coordinate system. Therefore, if the same baseline is used continuously, it will cause a decrease in exposure accuracy, including overlay accuracy (baseline drift), and it is necessary to remeasure the baseline at regular intervals.

[0006] While exposure accuracy can be maintained by remeasuring the baseline, productivity decreases. Therefore, techniques have been proposed to optimize the timing of baseline updates in order to maintain exposure accuracy while maintaining productivity (i.e., to achieve both exposure accuracy and productivity) (see Patent Documents 1 and 2). Patent Document 1 discloses a technique for updating the baseline by performing through-the-mirror mark detection and off-axis mark detection separately at the necessary timings. Patent Document 2 discloses a technique for updating the baseline only when the baseline is fluctuating, based on the interaction between the heat generated by the exposure light and the baseline.

[0007] Furthermore, a technique is known that selectively uses high-precision measurement with multiple mark detections and high-speed measurement with fewer mark detections for baseline measurement. For example, first, high-precision measurement is performed to obtain a baseline and generate reference data. At subsequent measurement timings, only high-speed measurement is performed, and if there is no difference greater than the tolerance between the measurement and the reference data, the reference data is used for correction. On the other hand, if a difference greater than the tolerance occurs, it is determined that the amount of baseline fluctuation (change over time) is large, and the reference data is regenerated using high-precision measurement. With this technique, high-precision measurement is performed when the baseline fluctuates significantly, and high-speed measurement is performed otherwise, thus achieving both exposure accuracy and productivity. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2006-344739 [Patent Document 2] Japanese Patent Publication No. 2005-64371 [Overview of the project] [Problems that the invention aims to solve]

[0009] In technologies that selectively use high-precision and high-speed measurements for baseline measurement, the frequency of high-precision measurements significantly impacts productivity. In such technologies, if the current baseline correction value is deemed close to the true baseline value, re-measuring the baseline (reference baseline) is unnecessary. However, if the difference between the reference data (judgment value) and the measurement result obtained by high-speed measurement exceeds the tolerance due to changes in the baseline over time, the baseline will be re-measured, leading to a decrease in productivity.

[0010] This invention has been made in view of the problems of the prior art, and its exemplary objective is to provide a technique that is advantageous for determining a judgment value for determining the validity of baseline measurements. [Means for solving the problem]

[0011] To achieve the above objective, a determination method as one aspect of the present invention is a determination method for determining a determination value for determining the validity of a baseline measurement value representing the distance between the optical axis of a first scope that detects a mark via a projection optical system that projects light from a master plate onto a substrate and the optical axis of a second scope that detects a mark without using the projection optical system, characterized by comprising: a first step of obtaining a reference baseline from the detection results of a first number of times by the first scope and the second scope; a second step of obtaining a baseline measurement value from the detection results of a second number of times less than the first number of times by the first scope and the second scope; and a third step of determining the determination value to be used after obtaining the baseline measurement value, based on the reference baseline obtained in the first step and the baseline measurement value obtained in the second step.

[0012] Further objects or other aspects of the present invention will be revealed by embodiments described below with reference to the accompanying drawings. [Effects of the Invention]

[0013] According to the present invention, for example, it is possible to provide a technique that is advantageous for determining a judgment value for determining the validity of baseline measurements. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram showing the configuration of an exposure apparatus as one aspect of the present invention. [Figure 2] This is a flowchart illustrating the method for determining the baseline correction amount in the first embodiment. [Figure 3] This is a flowchart illustrating the method for determining the baseline correction amount in the second embodiment. [Modes for carrying out the invention]

[0015] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0016] Figure 1 is a schematic diagram showing the configuration of an exposure apparatus 100 as one aspect of the present invention. The exposure apparatus 100 is used in the lithography process, which is a process for manufacturing articles including devices, and is a lithography apparatus that forms a pattern on a substrate (wafer or plate) by exposing it through a master plate (reticle or mask). In this embodiment, the exposure apparatus 100 is embodied as an exposure apparatus for manufacturing flat panel displays (FPDs). The exposure apparatus 100 projects the pattern of the master plate onto the substrate via a projection optical system, thereby transferring the pattern of the master plate to the substrate.

[0017] In this specification and the accompanying drawings, directions are indicated using an XYZ coordinate system, where the Z-axis is defined as the direction perpendicular to the surface of the substrate (vertical direction), and the X-axis and Y-axis are defined as two directions parallel to the plane perpendicular to the Z-axis and perpendicular to each other. Furthermore, the directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are defined as the X direction, Y direction, and Z direction, respectively.

[0018] As shown in Figure 1, the exposure apparatus 100 includes an illumination optical system 1, an alignment scope 2, a projection optical system 4, a master plate stage 9, a substrate stage 10, a control unit 11, and an off-axis scope 12.

[0019] The illumination optical system 1 includes, for example, optical elements such as lenses and mirrors, and illuminates the original plate 3 with light from a light source (not shown). The light source includes, for example, a mercury lamp and an elliptical mirror. In this embodiment, the illumination optical system 1 forms an illumination area of ​​a predetermined shape and illuminates a portion of the original plate 3.

[0020] The projection optical system 4 projects the pattern (image) of the master plate 3, illuminated by the illumination optical system 1, onto the substrate 8. The projection optical system 4 may be composed of any of the following optical systems: a 1:1 imaging optical system, a magnifying imaging optical system, or a reduction imaging optical system. The master plate 3 is positioned at the object plane of the projection optical system 4, and the substrate 8 is positioned at the image plane of the projection optical system 4.

[0021] In this embodiment, the projection optical system 4 is configured as a reflective optical system including a concave mirror 5, a mirror 6, and a convex mirror 7. The light from the original plate 3 illuminated by the projection optical system 4 (the image of the pattern on the original plate 3) passes through the mirror 6, the concave mirror 5, the convex mirror 7, the concave mirror 5, and the mirror 6 in the projection optical system 4, and is imaged onto the substrate 8 at 1:1 magnification. The projection optical system 4 may be configured as a refractive optical system mainly using lenses, or as a reflective-refractive optical system using lenses and mirrors, or as a plurality of imaging optical systems.

[0022] The master plate stage 9 includes a master plate holding mechanism for holding the master plate 3, a position adjustment mechanism for adjusting the position of the master plate 3 in the X and Y directions, and a rotation adjustment mechanism for adjusting the rotation angle of the master plate 3 around the X and Y axes.

[0023] The substrate stage 10 includes a substrate holding mechanism for holding the substrate 8, a position adjustment mechanism for adjusting the position of the substrate 8 in the X, Y, and Z directions, and a rotation adjustment mechanism for adjusting the rotation angle of the substrate 8 around the X, Y, and Z axes.

[0024] Alignment Scope 2 is a scope (first scope) for performing alignment measurements using a through-the-mirror method. Alignment Scope 2 detects (images) the alignment marks provided on the original plate 3 and the substrate 8 via the projection optical system 4 and measures the position of the alignment marks.

[0025] The off-axis scope 12 is a scope (second scope) for performing alignment measurement using the off-axis method. The off-axis scope 12 detects (images) the alignment marks provided on the substrate 8 without going through the projection optical system 4 and measures the position of the alignment marks.

[0026] The control unit 11 is composed of a computer (information processing device) including, for example, a CPU and memory. The control unit 11 comprehensively controls each part of the exposure apparatus 100 according to a program stored in a memory unit or the like to operate the exposure apparatus 100. The control unit 11 controls the exposure process of transferring the pattern of the master plate 3 onto the substrate 8 and various processes related to the exposure process.

[0027] For example, the control unit 11 indirectly controls the position and angle of the master plate 3 and the substrate 8 by driving the master plate stage 9 and the substrate stage 10 based on the position and angle measured by position measuring instruments such as an interferometer and an encoder. The control unit 11 also determines a baseline representing the positional relationship between the alignment scope 2 and the off-axis scope 12 based on the alignment mark detection results from the alignment scope 2 and the alignment mark detection results from the off-axis scope 12. Then, the control unit 11 uses the baseline to determine a correction amount for the position of the substrate stage 10 and transfers the pattern of the master plate 3 to the substrate 8 while moving the master plate 3 and the substrate 8 synchronously in a predetermined direction.

[0028] Here, the baseline refers to the distance the same mark needs to travel (the distance the substrate stage 10 needs to travel) to detect the same mark and obtain the same detection result with both the alignment scope 2 and the off-axis scope 12. Therefore, in this embodiment, the baseline is defined as the distance between the optical axis of the alignment scope 2 and the optical axis of the off-axis scope 12.

[0029] In the exposure apparatus 100, the baseline fluctuates due to factors such as heat generated by the exposure light and the driving of the substrate stage 10. Therefore, if the same baseline is used continuously, it will cause a decrease in exposure accuracy, including overlay accuracy (baseline drift). Consequently, it is necessary to determine the baseline correction amount, that is, to determine the baseline correction amount, in accordance with the fluctuations in the baseline.

[0030] The baseline reference value, which serves as the basis for the baseline correction amount, can be obtained with high accuracy while suppressing variance by performing high-precision measurements through multiple mark detections. However, multiple mark detections may reduce productivity. Therefore, in this embodiment, a judgment value and tolerance are provided to determine the validity of the baseline measurement value, and a new baseline reference value is determined; that is, the necessity of updating the baseline reference value is confirmed, and the frequency (number of times) of updating the baseline reference value is optimized.

[0031] <First Embodiment> Figure 2 is a flowchart illustrating the method for determining the baseline correction amount in the first embodiment. This determination method includes a step (determination method) for determining a judgment value for determining the validity of the baseline measurement value, and is executed by the control unit 11 comprehensively controlling each part of the exposure apparatus 100. Thus, in this embodiment, the control unit 11 functions as a processing unit that performs the process of determining a judgment value for determining the validity of the baseline measurement value.

[0032] In S11, the control unit 11 determines whether the job currently running is the first job. If the job currently running is not the first job, i.e., if it has been executed once before, the baseline reference value M is set. base A baseline (reference value) is required. Therefore, the baseline reference value M baseDepending on the presence or absence of [[ID=]], it is possible to determine whether the job being executed is the first job. If the job being executed is the first job, the process proceeds to S12. If the job being executed is not the first job, the process proceeds to S14.

[0033] In S12, the control unit 11 causes the alignment scope 2 and the off-axis scope 12 to perform high-precision measurement, and obtains the baseline reference value M base . Specifically, the detection of the alignment mark by the alignment scope 2 and the detection of the alignment mark by the off-axis scope 12 are performed a number of times (the first number including a plurality of times), for example, 16 times, and the respective detection results are obtained. Here, the results of the multiple detections are the results of detecting the alignment mark for one substrate 8 (the shot area thereof) by each of the alignment scope 2 and the off-axis scope 12. However, the results of the multiple detections may be the results of detecting the alignment mark for a plurality of substrates 8. Then, the baseline reference value M base is obtained from the 16 detection results by the alignment scope 2 and the off-axis scope 12. In the present embodiment, the average value of the 16 detection results by the alignment scope 2 and the off-axis scope 12 is used as the baseline reference value M base . Thus, by averaging the multiple detection results, the measurement errors of the alignment scope 2 and the off-axis scope 12 are averaged out, and the baseline reference value M base can be made closer to the true value of the baseline. However, when obtaining the baseline reference value M base , as long as the baseline reference value M base can be made closer to the true value of the baseline, it is not limited to averaging the multiple detection results. For example, by using statistical processing (statistical methods), the statistical value of the 16 detection results by the alignment scope 2 and the off-axis scope 12 may be used as the baseline reference value M base . Also, by a method using the standard deviation, the baseline reference value M is obtained from the 16 detection results by the alignment scope 2 and the off-axis scope 12.base You may also request this.

[0034] In S13, the control unit 11 determines a judgment value T1 for determining the validity of the baseline measurement value to be used in the first lot. In this embodiment, the baseline reference value M obtained in S12 base This is determined as the judgment value T1. A lot is the unit (manufacturing unit) for processing substrate 8.

[0035] In S14, the control unit 11 determines whether the substrate 8 to be aligned is the first substrate in the lot. Substrates from the same lot tend to be stored in the same environment and have the same characteristics in the manufacturing plant. Therefore, in this embodiment, the baseline is corrected and exposure is performed using the same baseline correction amount for substrates from the same lot. If substrate 8 is the first substrate in the lot, the process proceeds to S15; if substrate 8 is not the first substrate in the lot, the process proceeds to S20.

[0036] In S15, the control unit 11 causes the alignment scope 2 and the off-axis scope 12 to perform high-speed measurements and acquire baseline measurement values ​​(baseline measurement values). Specifically, the detection of alignment marks by the alignment scope 2 and the detection of alignment marks by the off-axis scope 12 are performed a small number of times (a second number of times which is fewer than the first number of times), for example, once, and the detection results are acquired. These detection results are the results of detecting alignment marks on one substrate 8 (shot area) by the alignment scope 2 and the off-axis scope 12, respectively. Then, the baseline measurement value is determined from the single detection result by the alignment scope 2 and the off-axis scope 12. Here, the baseline measurement value acquired in the nth lot (n is an integer of 1 or more) is called the baseline measurement value M. n This is how it is written.

[0037] In this embodiment, the number of times alignment marks are detected in high-speed measurement (S15) is set to one. However, the purpose of high-speed measurement is to measure faster than high-precision measurement (S12). Therefore, the number of times alignment marks are detected in high-speed measurement (second count) can be less than the number of times alignment marks are detected in high-precision measurement (first count). For example, the number of times alignment marks are detected in high-speed measurement may be one or more, or multiple times. Note that if the number of times alignment marks are detected in high-speed measurement is multiple, the baseline reference value M base Similarly, the baseline measurement value M is the average value obtained by averaging multiple detection results or the statistical value obtained by statistically processing multiple detection results. n That is also acceptable.

[0038] In S16, the control unit 11 determines the determination value T for the nth lot. n And the baseline measurement value M obtained in S15 n The following equation (1) is used to compare the two values ​​and determine whether the difference exceeds the tolerance (acceptable range). The judgment value T n and baseline measurement M n If the difference exceeds the tolerance, proceed to S17 and the judgment value T n and baseline measurement M n If the difference does not exceed the tolerance, proceed to S19. Note that in equation (1), Tol is the judgment value T n and baseline measurement M n Difference T n -M n This represents the tolerance (acceptable amount of error). Also, if the substrate 8 to be aligned is the first lot, the baseline measurement value M obtained in S15 is also represented. n The judgment value T to be compared with (M1) n This becomes the judgment value T1 determined in S13. |T n -M n |>Tol ···(1) The baseline correction amount is set to the baseline reference value M in subsequent sequences. baseThe judgment value T is calculated (determined) using the following: n (For example, baseline reference value M) base ) and baseline measurement M n If the difference exceeds the tolerance, the actual baseline is the baseline reference value M. base It is thought that there has been a significant change from the baseline. Therefore, after the baseline change, the baseline reference value M before the change base If correction is performed using the baseline correction amount calculated using [the specified method], exposure accuracy, including overlay accuracy, will decrease. Therefore, the judgment value T n and baseline measurement M n If the difference exceeds the tolerance, i.e., if the difference is large, it is necessary to determine the baseline reference value after the baseline change.

[0039] In S17, the control unit 11 causes the alignment scope 2 and the off-axis scope 12 to perform high-precision measurements, and sets the baseline reference value M base The results are reacquired. Specifically, similar to S12, the detection of alignment marks using the alignment scope 2 and the detection of alignment marks using the off-axis scope 12 are performed multiple times (first number of times), for example 16 times, and the detection results for each are acquired. Then, a new baseline reference value M is obtained from the new 16 detection results from the alignment scope 2 and the off-axis scope 12. base We calculate the baseline reference value M. base By updating this, it is possible to adapt to the baseline after the change. Also, since the high-precision measurement in S16 is performed on the nth lot, the baseline measurement value M n Baseline reference value M base Update with the same value as above.

[0040] In S18, the control unit 11 determines the decision value T to be used for the (n+1)th lot. n+1 Determine the baseline reference value M obtained in S17. base The judgment value T n+1 This will be decided.

[0041] In S19, the control unit 11 sets the baseline reference value M base And the baseline measurement value M n Based on this, the (n+1)th lot (baseline measurement M) n The judgment value T used after obtaining it n+1 Determine (calculate) the baseline reference value M. base Because it is measured with high precision, it is superior in terms of reliability. Baseline measurement value M n Since it was measured with the current lot, it is superior in terms of responsiveness. Therefore, the baseline reference value M base And the baseline measurement value M n By combining these, the judgment value T is closer to the true value of the baseline than before. n+1 It becomes possible to make a decision.

[0042] Note that the judgment value T n+1 Baseline reference value M used when determining base If S17 has not been performed, the baseline reference value M obtained in S12 is not used. base Therefore, if S17 has been completed, the baseline reference value M obtained (updated) in S17 will be used. base Similarly, the judgment value T n+1 Baseline measurement value M used when determining n If S17 has not been performed, the baseline measurement value M obtained in S15 will not be used. n Therefore, if S17 has been completed, the baseline reference value M updated in S17 will be used. base This is equivalent to [the above].

[0043] Here, in S19, the judgment value T n+1 An example of a specific method for determining the baseline reference value M will be described. base and baseline measurement value M n By assigning weights to each of them, the judgment value T n+1 Determine the baseline measurement value M. n If we denote the weight assigned to it as weight W, then the baseline reference value M baseA weight (1-W) is assigned to it. Therefore, the decision value T n+1 And the baseline measurement value M n And, baseline reference value M base The relationship can be formalized as follows: (2) T i+1 =WM i +(1-W)M base ...(2) In equation (2), i represents the elapsed time since the start of measurement and is interchangeable with the lot number, i.e., n, which represents periodic measurement. i represents the baseline measurement obtained by high-speed measurement after i time has elapsed, and W represents the weight (weighting ratio) assigned to the baseline measurement obtained by performing high-speed measurement.

[0044] Referring to equation (2), the baseline measurement M i and baseline reference value M base These are measured values, and by assigning weights W and (1-W) to each (multiplying them), a judgment value T is obtained. i+1 The baseline measurement value M is determined. i Because the measurement was performed at high speed, i.e., under low-precision conditions, it contains variability. In other words, the baseline measurement M i This value reflects the measurement reproducibility of the alignment scope 2 and the off-axis scope 12, respectively. Therefore, as shown in equation (2), the baseline measurement value M i Judgment value T including i+1 It will also be distributed.

[0045] In the exposure apparatus 100, the baseline fluctuation caused by continuous exposure is shown in the following equation (3). M true (i) = A(i) + M base0 ...(3) In equation (3), i represents the elapsed time from the start of measurement, and M true (i) represents the baseline (experimental value), A(i) represents the change over time from the baseline, and M base0represents the first measured value of the baseline. Equation (3) schematically represents the baseline (variation), which is formulated by statistical processing from the values obtained in the experiment.

[0046] Here, the determination value T shown in Equation (2) i+1 is a value for determining the baseline M true (i). Therefore, the difference between the determination value T i+1 and the baseline M true (i) preferably becomes small. The standard deviation S of the determination value T i+1 is represented by the following Equation (4).

[0047]

Equation

[0048] Referring to Equation (4), when the standard deviation S is sufficiently small, the distribution of the determination value T i+1 is close to the baseline M true (i) shown in Equation (3), indicating correctness. Also, as shown in Equation (2), since the determination value T i+1 is determined by the weight W, when the standard deviation S is sufficiently small, it also indicates that the weight W is correct.

[0049] Therefore, in this embodiment, the weight W is calculated according to the following Equation (5). Equation (5) is obtained by substituting Equations (2) and (3) into Equation (4).

[0050]

Equation

[0051] The weight W is substituted in the range from 0 to 1 so that the standard deviation S shown in Equation (5) is minimized. Since the weight W when the standard deviation S is minimized is considered to be closest to the true value, the weight W when the standard deviation S is minimized is adopted as the weight given to the baseline measurement value M n . Referring to Equation (5), for the baseline measurement value M iis a value that reflects the measurement reproducibility of each of the alignment scope 2 and the off-axis scope 12, and the amount of change A(i) of the baseline over time is a value that reflects the change of the baseline over time. Thus, the weight W is calculated (determined) based on the reliability of the detection results obtained by each of the alignment scope 2 and the off-axis scope 12. Specifically, it is calculated based on the measurement reproducibility of each scope and the change of the baseline over time.

[0052] Also, the weight W can be temporarily changed (increased or decreased) according to the number of times (the first number and the second number) that the alignment scope 2 and the off-axis scope 12 detect the alignment mark, so as to reflect the reliability of each alignment measurement value. In addition, by changing the weight W according to the job, it is also possible to reflect the reliability for each job.

[0053] In S20, the control unit 11 uses the baseline reference value M base , or the baseline reference value M base and the baseline measurement value M n to determine (calculate) the baseline correction amount X n to be used in the nth lot. In this embodiment, when passing through S19, based on the baseline reference value M base and the baseline measurement value M n , for example, similar to the determination value T n+1 , the baseline correction amount X n is determined. Also, when only passing through S12 or when passing through S17, the baseline correction amount X base is determined based on the baseline reference value M n . For example, the baseline reference value M base obtained in S12, or the baseline reference value M base obtained in S17, is determined as the baseline correction amount X n . However, the method for determining the baseline correction amount Xn can apply techniques well-known in the art and is not limited to the above-described method.

[0054] Thus, according to this embodiment, a judgment value for determining the validity of baseline measurements can be determined (updated as needed) in response to fluctuations in the baseline. Therefore, it is possible to confirm the need to newly determine a baseline reference value, that is, to update the baseline reference value, and to optimize the frequency (number of times) that the baseline reference value is updated. This makes it possible to achieve both exposure accuracy and productivity in the exposure apparatus 100.

[0055] <Second Embodiment> Figure 3 is a flowchart illustrating the method for determining the baseline correction amount in the second embodiment. This determination method includes a step (determination method) for determining a judgment value for determining the validity of the baseline measurement value, and is executed by the control unit 11 comprehensively controlling each part of the exposure apparatus 100. Thus, in this embodiment, the control unit 11 functions as a processing unit that performs the process of determining a judgment value for determining the validity of the baseline measurement value.

[0056] In this embodiment, as shown in Figure 3, S24 is provided instead of S19 in the first embodiment, i.e., determining the decision value according to equation (2). Furthermore, in this embodiment, S21, S22, and S23 are provided in order to use the confidence level regarding the baseline correction amount.

[0057] In S21, the control unit 11 determines (calculates) the confidence level R for the baseline correction value. The confidence level R is the baseline reference value M that serves as the basis for the baseline correction value. base This indicates the confidence level that the difference between the measured value and the baseline true value is within an acceptable range. In this embodiment, as an example of a specific method, a method for determining the confidence level R based on the elapsed time after high-precision measurement is described.

[0058] If a long time has elapsed since the high-precision measurement was performed, the baseline measurement reproducibility may decrease due to factors such as heat generation from exposure light and driving of the substrate stage 10. In this case, in S20, the baseline reference value M base or baseline measurement Mn Errors may occur in the baseline correction value determined using this method. Therefore, it is preferable to lower the confidence level R when a long time has elapsed since the high-precision measurement was performed. For example, the confidence level R is calculated using the elapsed time ET since the high-precision measurement was performed according to the following equation (6). R = 1 / ET ... (6) Furthermore, the calculation of the confidence level R is not limited to being based on the elapsed time since the high-precision measurement was performed. For example, the confidence level R may be determined based on the measurement reproducibility of the alignment scope 2 and the off-axis scope 12, the change in the baseline over time, the number of processing lots after the high-precision measurement was performed, and the number of times the judgment value or baseline correction amount was updated (determined). In other words, the confidence level R may be determined based on at least one of these factors.

[0059] In S22, the control unit 11 determines whether the confidence level R determined in S21 is greater than the threshold TolR, according to the following equation (7). R>TolR ···(7) In equation (7), the threshold TolR represents the acceptable value of the confidence level R.

[0060] When comparing the confidence level R with the threshold TolR, if the confidence level R is not greater than the threshold TolR, i.e., less than or equal to the threshold TolR (a low confidence level R), it is highly likely that the current baseline correction amount is far from the true value of the baseline. In this case, determining (updating) a new judgment value may lead to the misconception that the difference between the baseline correction amount and the true value of the baseline is small. Therefore, if the confidence level R is not greater than the threshold TolR, the system proceeds to S20 without determining a new judgment value (without going through S24).

[0061] On the other hand, when comparing the confidence level R with the threshold TolR, if the confidence level R is greater than the threshold TolR (i.e., the confidence level R is high), it can be inferred that the current baseline correction amount is close to the true value of the baseline. In this case, it is preferable to update the judgment value to reduce the frequency of misjudgments (and the resulting reacquisition of the baseline reference value) in determining whether the difference between the judgment value and the baseline measurement value exceeds the tolerance (S16). Therefore, if the confidence level R is greater than the threshold TolR, the process proceeds to S23.

[0062] In S23, the control unit 11 calculates the baseline measurement value M based on the confidence level R determined in S21, according to the following equation (8). n Determine the weight W (weighting ratio) to be assigned to it. W=R ···(8) In S24, the control unit 11 receives the baseline measurement value M obtained in the nth lot (where n is an integer greater than or equal to 1). n The judgment value T used in the nth lot. n Based on this, the decision value T to be used for the (n+1)th lot. n+1 The baseline measurement value M is determined (calculated) by having the alignment scope 2 and the off-axis scope 12 perform high-speed measurements. n and the judgment value T used in the previous lot. n Therefore, the judgment value T to be used in this lot n+1 Determine the following. Note that the judgment value T n This is the baseline reference value M obtained in S12. base , and the baseline measurements M1~M for each lot up to the nth lot obtained in S15. n-1 (Baseline M1~M) n It is determined based on the following.

[0063] Here, in S24, the judgment value T n+1 An example of a specific method for determining this will be explained. For the first lot, since the judgment value T0 used in the previous lot does not exist, the judgment value T1 is determined according to the following equation (9), similar to the first embodiment. T1 = WM1 + (1 - W)M base ...(9) For the second lot, the judgment value T2 is determined using the judgment value T1 according to the following formula (10). T2 = WM2 + (1 - W)T1 ... (10) Generalizing equation (10), the decision value T used for the (n+1)th lot is n+1 This can be expressed by the following equation (11). T n+1 =WM n+1 +(1-W)T n ...(11) Thus, in this embodiment, the nth decision value T n And the baseline measurement value M n By combining this, the decision value T used for the (n+1)th lot is n+1 Determine the following: In this case, the determination value T is determined, as in the first embodiment. n and baseline measurement value M n Each of these is given a weight. Specifically, the baseline measurement M n If we denote the weight assigned to the judgment value as weight W, then the judgment value X n It is recommended to assign a weight (1-W) to it. The weight W is the weight W determined in S23.

[0064] Comparing equation (11) and equation (2), equation (11) includes information about baseline measurements obtained from the high-speed measurements performed on the previous lot. Therefore, in equation (11), the baseline measurement M n-1 Baseline measurement M n The judgment value T includes information on the change over time, such as how it changed. n+1 It becomes possible to determine the judgment value T. n+1 Since the total number of baseline measurements used in determining the alignment scope increases, the influence of the measurement reproducibility of the alignment scope 2 and the off-axis scope 12 can be suppressed.

[0065] In this embodiment as well, the determination value T n and baseline measurement M nIf the difference exceeds the tolerance, high-precision measurement will be performed to determine the baseline reference value M base and baseline measurement value M n Reacquire the baseline measurement value M (S17). n This is the baseline measurement value M obtained by high-speed measurement. n Compared to that, it is superior in terms of reliability and reproducibility.

[0066] Thus, according to this embodiment, a judgment value for determining the validity of the baseline measurement value can be determined (updated as needed) according to the baseline fluctuation and the reliability of the baseline correction amount. Therefore, it is possible to confirm the need to newly determine the baseline reference value, that is, to update the baseline reference value, and to optimize the frequency (number of times) of updating the baseline reference value. This makes it possible to achieve both exposure accuracy and productivity in the exposure apparatus 100.

[0067] In the first and second embodiments, the case in which high-speed measurement is performed on the leading substrate of a lot to obtain baseline measurement values ​​was described, but the invention is not limited to this. For example, baseline measurement values ​​may be obtained by performing high-speed measurement on a substrate-by-substrate basis.

[0068] 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 having 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.

[0069] The method for manufacturing articles in the embodiments of the present invention is suitable for manufacturing articles such as flat panel displays, liquid crystal display elements, semiconductor elements, and MEMS. This manufacturing method includes the steps of exposing a substrate coated with a photosensitive material using the exposure apparatus 100 (exposure process) described above, and developing the exposed photosensitive material. Furthermore, an etching process or ion implantation process is performed on the substrate using the pattern of the developed photosensitive material as a mask to form a circuit pattern on the substrate. These processes of exposure, development, etching, etc., are repeated to form a circuit pattern consisting of multiple layers on the substrate. In a subsequent process, dicing (processing) is performed on the substrate on which the circuit pattern has been formed, followed by chip mounting, bonding, and inspection processes. This manufacturing method may also include other well-known processes (oxidation, film formation, vapor deposition, doping, planarization, resist peeling, 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.

[0070] The disclosures herein include the following determination methods, information processing devices, exposure devices, and methods for manufacturing articles.

[0071] (Item 1) A determination method for determining a determination value for determining the validity of a baseline measurement value representing the distance between the optical axis of a first scope that detects a mark via a projection optical system that projects light from the original plate onto a substrate, and the optical axis of a second scope that detects a mark without using the projection optical system, A first step of obtaining a reference baseline from the detection results of the first number of times by the first scope and the second scope, A second step of obtaining a baseline measurement value from the detection results of a second number of times, which is less than the first number of times, using the first scope and the second scope. A third step in which, based on the reference baseline obtained in the first step and the measured value of the baseline obtained in the second step, a determination value to be used after obtaining the measured value of the baseline is determined, A determination method characterized by having the following:

[0072] (Item 2) The determination method according to item 1, characterized in that the detection result for the first number of times is the result of detecting a mark on one substrate.

[0073] (Item 3) In the second step, the baseline measurement value is obtained for the nth lot (where n is an integer greater than or equal to 1), In the third step, the judgment value to be used for the (n+1)th lot is determined. The determination method according to item 1 or 2, characterized by the above.

[0074] (Item 4) The process further includes a fourth step of determining whether the difference between the baseline measurement value obtained in the second step and the judgment value exceeds the tolerance. If the difference does not exceed the tolerance, the third step is performed. A determination method described in any one of items 1 to 3, characterized by the above.

[0075] (Item 5) If the difference exceeds the tolerance, instead of the third step, The determination method according to item 4, characterized in that a new reference baseline is obtained from the new detection results of the first number of times by the first scope and the second scope, and the new reference baseline is determined as the determination value.

[0076] (Item 6) The determination method according to any one of items 1 to 5, characterized in that in the third step, the determination value is determined by assigning weights to the reference baseline obtained in the first step and the measured value of the baseline obtained in the second step.

[0077] (Item 7) The determination method according to any one of items 1 to 5, characterized in that in the third step, a weight (1-W) is assigned to the reference baseline obtained in the first step, and the determination value is determined by assigning the weight W to the measured value of the baseline obtained in the second step.

[0078] (Item 8) A fifth step is to determine the confidence level, which indicates the degree to which the difference between the reference baseline obtained in the first step and the true value of the baseline is within an acceptable range. A sixth step involves determining whether the confidence level determined in the fifth step is greater than a threshold, It further possesses, The determination method according to item 1 or 2, characterized in that, if the confidence level determined in the fifth step is greater than a threshold, the third step determines the judgment value to be used for the first lot by assigning weights determined based on the confidence level determined in the fifth step to each of the reference baseline obtained in the first step and the baseline measurement values ​​obtained in the second step.

[0079] (Item 9) The determination method according to item 8, characterized in that in the third step, the determination value to be used in the (n+1)th lot is determined by assigning weights determined based on the confidence level determined in the fifth step to each of the determination value used in the nth lot (where n is an integer of 1 or more) and the baseline measurement value of the (n+1)th lot obtained in the second step.

[0080] (Item 10) The determination method according to item 9, characterized in that, in the third step, the determination value is determined by assigning a weight (1-W) to the determination value used in the nth lot and assigning a weight W to the baseline measurement value of the (n+1)th lot.

[0081] (Item 11) The determination method according to item 6 or 8, characterized in that the weight is calculated based on the measurement reproducibility of the first scope, the measurement reproducibility of the second scope, and the change in the baseline over time.

[0082] (Item 12) The determination method according to item 8, characterized in that the reliability is determined based on at least one of the following: the measurement reproducibility of the first scope, the measurement reproducibility of the second scope, the change in the baseline over time, the elapsed time after the first process is performed, the number of processing lots after the first process is performed, and the number of times the judgment value has been determined.

[0083] (Item 13) An information processing device, The system includes a processing unit that determines a determination value for determining the validity of a baseline measurement value, which represents the distance between the optical axis of a first scope that detects marks via a projection optical system that projects light from the original plate onto the substrate, and the optical axis of a second scope that detects marks without using the projection optical system. The aforementioned processing unit, A reference baseline is obtained from the detection results of the first count by the first scope and the second scope. A baseline measurement value is obtained from the detection results of a second number of times, which is less than the first number of times, obtained by the first and second scopes. Based on the aforementioned reference baseline and the measured value of the baseline, the determination value to be used after obtaining the measured value of the baseline is determined. An information processing device characterized by having the following:

[0084] (Item 14) An exposure apparatus for exposing a substrate via a master plate, A projection optical system that projects light from the original plate onto the substrate, A first scope that detects a mark via the aforementioned projection optical system, A second scope for detecting marks without using the aforementioned projection optical system, The information processing device described in item 13, An exposure apparatus characterized by having the following.

[0085] (Item 15) The process of exposing a substrate using the exposure apparatus described in item 14, A step of developing the exposed substrate, A process for manufacturing an article from the developed substrate, A method for manufacturing an article, characterized by having the following:

[0086] 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]

[0087] 100: Exposure apparatus 2: Alignment scope 3: Master plate 4: Projection optics 8: Substrate 11: Control unit 12: Off-axis scope

Claims

1. A determination method for determining a determination value for determining the validity of a baseline measurement value representing the distance between the optical axis of a first scope that detects a mark via a projection optical system that projects light from the original plate onto a substrate, and the optical axis of a second scope that detects a mark without using the projection optical system, A first step of obtaining a reference baseline from the detection results of the first number of times by the first scope and the second scope, A second step of obtaining a baseline measurement value from the detection results of a second number of times, which is less than the first number of times, obtained by the first scope and the second scope. A third step in which, based on the reference baseline obtained in the first step and the measured value of the baseline obtained in the second step, a determination value to be used after obtaining the measured value of the baseline is determined, A determination method characterized by having the following:

2. The determination method according to claim 1, characterized in that the detection result for the first number of times is the result of detecting a mark on one substrate.

3. In the second step, the baseline measurement value is obtained for the nth lot (where n is an integer of 1 or more), In the third step, the determination value to be used for the (n+1)th lot is determined. The determination method according to feature 1.

4. The process further includes a fourth step of determining whether the difference between the baseline measurement value obtained in the second step and the judgment value exceeds the tolerance. If the difference does not exceed the tolerance, the third step is performed. The determination method according to feature 1.

5. If the difference exceeds the tolerance, instead of the third step, The determination method according to claim 4, characterized in that a new reference baseline is obtained from the new detection results of the first number of times by the first scope and the second scope, and the new reference baseline is determined as the determination value.

6. The determination method according to claim 1, characterized in that, in the third step, the determination value is determined by assigning weights to the reference baseline obtained in the first step and the measured value of the baseline obtained in the second step.

7. The determination method according to claim 1, characterized in that, in the third step, the determination value is determined by assigning a weight (1-W) to the reference baseline obtained in the first step and assigning a weight W to the measured value of the baseline obtained in the second step.

8. A fifth step is to determine a confidence level that indicates the degree to which the difference between the reference baseline obtained in the first step and the true value of the baseline is within an acceptable range, A sixth step involves determining whether the confidence level determined in the fifth step is greater than a threshold, It further possesses, The determination method according to claim 1, characterized in that, if the confidence level determined in the fifth step is greater than a threshold, the third step determines the judgment value to be used for the first lot by assigning weights determined based on the confidence level determined in the fifth step to each of the reference baseline obtained in the first step and the baseline measurement values ​​obtained in the second step.

9. The determination method according to claim 8, characterized in that in the third step, the determination value to be used in the (n+1)th lot is determined by assigning weights determined based on the confidence level determined in the fifth step to each of the determination value used in the nth lot (where n is an integer of 1 or more) and the baseline measurement value of the (n+1)th lot obtained in the second step.

10. The determination method according to claim 9, characterized in that, in the third step, the determination value is determined by assigning a weight (1-W) to the determination value used in the nth lot and assigning a weight W to the baseline measurement value of the (n+1)th lot.

11. The determination method according to claim 6 or 8, characterized in that the weight is calculated based on the measurement reproducibility of the first scope, the measurement reproducibility of the second scope, and the change in the baseline over time.

12. The determination method according to claim 8, characterized in that the reliability is determined based on at least one of the following: the measurement reproducibility of the first scope, the measurement reproducibility of the second scope, the change in the baseline over time, the elapsed time after the first process is performed, the number of processing lots after the first process is performed, and the number of times the judgment value has been determined.

13. An information processing device, The system includes a processing unit that determines a determination value for determining the validity of a baseline measurement value, which represents the distance between the optical axis of a first scope that detects marks via a projection optical system that projects light from the original plate onto the substrate, and the optical axis of a second scope that detects marks without using the projection optical system. The aforementioned processing unit, A reference baseline is obtained from the detection results of the first count by the first scope and the second scope. A baseline measurement value is obtained from the detection results of a second number of times, which is less than the first number of times, obtained by the first and second scopes. Based on the aforementioned reference baseline and the measured value of the baseline, the determination value to be used after obtaining the measured value of the baseline is determined. An information processing device characterized by having the following:

14. An exposure apparatus for exposing a substrate via a master plate, A projection optical system that projects light from the original plate onto the substrate, A first scope that detects a mark via the aforementioned projection optical system, A second scope for detecting marks without using the aforementioned projection optical system, The information processing apparatus according to claim 13, An exposure apparatus characterized by having the following.

15. A step of exposing a substrate using the exposure apparatus described in claim 14, A step of developing the exposed substrate, A process for manufacturing an article from the developed substrate, A method for manufacturing an article, characterized by having the following:

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