Analysis method and evaluation method

Abstract

To provide technology for quantitatively analyzing the state of a liquid film on a substrate in a substrate processing device.SOLUTION: Provided is an analysis method for analyzing the state of a liquid film on a rotating substrate of a liquid supplied to the substrate. The analysis method comprises: a step (S303) for calculating a first statistical amount from the luminance value of each pixel in a prescribed region of a video obtained by imaging the surface of the substrate; a step (S304) for calculating at least one second statistical amount which is a statistical amount of the time-series data of the first statistical amount; and a step (S305) for analyzing the state of a liquid film on the substrate on the basis of the first statistical amount and the at least one second statistical amount. The first statistical amount includes an average luminance value obtained by averaging luminance values and an average heterogeneity degree value obtained by averaging heterogeneity degrees of luminance values. The second statistical amount includes a statistical luminance amount representing a statistical amount of the average luminance value and / or a statistical heterogeneity degree amount representing a statistical amount of the average heterogeneity degree value. Thus, it is possible to quantitatively analyze the state of a liquid film on the substrate.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an analysis method for analyzing the state of a liquid film on a rotating substrate in a substrate processing apparatus.

Background Art

[0002] The cleaning process, which accounts for 30% to 40% of the semiconductor manufacturing process, has a significant impact on semiconductor quality and yield, and as semiconductor devices are miniaturized, there is an increasing need to address minute foreign matter and contamination. In semiconductor cleaning equipment, even a slight difference in operation can lead to a decline in output quality. In equipment inspections, it is necessary to observe not only the output quality of the equipment but also the control during operation as a factor contributing to the decline in output quality.

[0003] In the most common spin processor as a single-wafer cleaning apparatus for semiconductor substrates, chemicals or pure water are supplied to the rotating wafer for cleaning. Since the state of the liquid film on the substrate in the cleaning process is considered to affect the process result, it is required to observe, analyze, and evaluate the state of the liquid film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional efforts to install a video camera in the apparatus for inspecting the operation of the apparatus are described, for example, in Patent Document 1. In Patent Document 1, an event-based camera is used to observe the behavior of a substrate rotating at high speed. However, no mention is made of an index for quantifying and evaluating the state of the liquid film.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for quantitatively analyzing the state of a liquid film on a substrate in a substrate processing apparatus.

Means for Solving the Problems

[0007] In order to solve the above problems, a first invention of the present application is an analysis method for analyzing the state of a liquid film on a substrate of a liquid supplied to a rotating substrate in a substrate processing apparatus, comprising: a) obtaining luminance values of each pixel in a predetermined region from an image obtained by imaging the surface of the substrate, and calculating a first statistic from the luminance values; b) calculating a second statistic which is a statistic of time-series data of the first statistic; and c) analyzing the state of the liquid film on the substrate based on at least one of the first statistic and the second statistic, wherein the first statistic includes a luminance average value obtained by averaging the luminance values in the region and a non-uniformity average value obtained by averaging the non-uniformities of the luminance values in the region, and the second statistic includes at least one of a luminance statistic which is a statistic of time-series data of the luminance average value and a non-uniformity statistic which is a statistic of time-series data of the non-uniformity average value.

[0008] A second invention of the present application is the analysis method of the first invention, wherein the luminance statistic includes a luminance standard deviation value which is the standard deviation of the luminance values in the entire region.

[0009] A third invention of the present application is the analysis method of the first invention, wherein the non-uniformity statistic includes a non-uniformity standard deviation which is the standard deviation of the non-uniformities in the entire region.

[0010] A fourth invention of the present application is the analysis method of the first invention, wherein the non-uniformity statistic includes a non-uniformity differential moving average which is a moving average of a first derivative of a moving average of the non-uniformity average value obtained by averaging the non-uniformities in the entire region.

[0011] The fifth invention of the present application is the analysis method of the first invention, wherein the non-uniformity statistic includes a non-uniformity differential moving average which is a moving average of a first derivative of a moving average of a non-uniformity average value obtained by averaging the non-uniformity of the entire region. In the step a), the video captures the first state, a transition period from the first state to the second state, and the second state. In the step c), in the second state, the switching completion time when the liquid film on the substrate becomes stable is analyzed based on the non-uniformity differential moving average.

[0012] The sixth invention of the present application is the analysis method of the fifth invention, wherein the non-uniformity statistic includes a non-uniformity moving average differential value which is a first derivative of a moving average of a non-uniformity average value obtained by averaging the non-uniformity of the entire region, and a moving average of the non-uniformity moving average differential value. In the step c), the time when the moving average of the non-uniformity moving average differential value falls below a first threshold value which is a predetermined negative value is set as the start time of the transition period, and the time when the moving average of the non-uniformity moving average differential value exceeds a second threshold value after showing a negative peak a predetermined number of times is set as the switching completion time.

[0013] The seventh invention of the present application is an evaluation method for analyzing and evaluating the state of a liquid film on a rotating substrate of a liquid supplied to the substrate in a substrate processing apparatus, including: p) obtaining the luminance value of each pixel from a predetermined region of a video obtained by imaging the surface of each substrate when the same process is performed on a plurality of the substrates, and calculating a first statistic from the luminance values; q) calculating a second statistic which is a statistic of the time series data of the first statistic; and r) analyzing and evaluating the state of the liquid film on the substrate based on at least one of the first statistic and the second statistic. The first statistic includes a luminance average value obtained by averaging the luminance values of the region and a non-uniformity average value obtained by averaging the non-uniformity of the luminance values of the region. The second statistic includes at least one of a luminance statistic which is a statistic of the time series data of the luminance average value and a non-uniformity statistic which is a statistic of the time series data of the non-uniformity average value.

Advantages of the Invention

[0014] According to the first to seventh inventions of the present application, by analyzing the liquid film state using statistical values based on luminance values, the state of the liquid film on the substrate can be quantitatively analyzed.

[0015] In particular, according to the fifth and sixth inventions of the present application, the completion time of the switching of the state of the liquid film on the substrate can be analyzed.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

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Figure 11

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0018] <1. Overall Configuration of Substrate Processing Apparatus> FIG. 1 is a plan view of a substrate processing apparatus 100 which is an example of a manufacturing apparatus according to the present invention. This substrate processing apparatus 100 is an apparatus that supplies a processing liquid to the surface of a disk-shaped substrate W and processes the surface of the substrate W in a semiconductor wafer manufacturing process. The substrate W in the present embodiment is a silicon wafer. As shown in FIG. 1, the substrate processing apparatus 100 includes an indexer 101, a plurality of processing units 102, and a main transfer robot 103.

[0019] The indexer 101 is a part for loading the substrate W before processing from the outside and unloading the substrate W after processing to the outside. A plurality of carriers for accommodating a plurality of substrates W are arranged in the indexer 101. The indexer 101 also has a transfer robot (not shown). The transfer robot transfers the substrate W between the carriers in the indexer 101 and the processing unit 102 or the main transfer robot 103.

[0020] The processing unit 102 is a so-called single-substrate processing unit that processes the substrate W one by one. The plurality of processing units 102 are arranged around the main transfer robot 103. In the present embodiment, four processing units 102 arranged around the main transfer robot 103 are stacked in three stages in the height direction. That is, the substrate processing apparatus 100 in the present embodiment has a total of 12 processing units 102. The plurality of substrates W are processed in parallel in each processing unit 102. However, the number of processing units 102 provided in the substrate processing apparatus 100 is not limited to 12, and may be, for example, 1, 4, 8, 24, etc.

[0021] The main transfer robot 103 is a mechanism for transferring the substrate W between the indexer 101 and the plurality of processing units 102. The main transfer robot 103 has, for example, a hand for holding the substrate W and an arm for moving the hand. The main transfer robot 103 takes out the substrate W before processing from the indexer 101 and transfers it to the processing unit 102. Further, when the processing of the substrate W in the processing unit 102 is completed, the main transfer robot 103 takes out the substrate W after processing from the processing unit 102 and transfers it to the indexer 101.

[0022] <2. Configuration of the Processing Unit> Next, the detailed configuration of the processing unit 102 will be described. In the following, one of the plurality of processing units 102 included in the substrate processing apparatus 100 will be described, but the other processing units 102 have the same configuration.

[0023] FIG. 2 is a longitudinal sectional view of the processing unit 102. As shown in FIG. 2, the processing unit 102 includes a chamber 10, a substrate holding unit 20, a rotation mechanism 30, a processing liquid supply unit 40, a processing liquid collection unit 50, a shutter plate 60, a camera 70, and a control unit 80.

[0024] The chamber 10 is a housing that encloses a processing space 11 for processing the substrate W. The chamber 10 has a side wall 12 that surrounds the side portion of the processing space 11, a top plate portion 13 that covers the upper portion of the processing space 11, and a bottom plate portion 14 that covers the lower portion of the processing space 11. The substrate holding unit 20, the rotation mechanism 30, the processing liquid supply unit 40, the processing liquid collection unit 50, the shutter plate 60, and the camera 70 are housed inside the chamber 10. A carry-in / outlet for carrying the substrate W into and out of the chamber 10 and a shutter for opening and closing the carry-in / outlet are provided in a part of the side wall 12.

[0025] The substrate holding unit 20 is a mechanism that horizontally holds the substrate W inside the chamber 10. That is, the substrate holding unit 20 holds the substrate W in a posture in which the normal line of the substrate W faces the vertical direction. As shown in FIG. 2, the substrate holding unit 20 has a disk-shaped spin base 21 and a plurality of chuck pins 22.

[0026] The plurality of chuck pins 22 are provided at equal angular intervals along the outer peripheral portion of the upper surface of the spin base 21. The substrate W is held by the plurality of chuck pins 22 with the processed surface on which the pattern is formed facing upward. Each chuck pin 22 contacts the lower surface and the outer peripheral end surface of the peripheral portion of the substrate W, and supports the substrate W at a position above the upper surface of the spin base 21 with a slight gap therebetween.

[0027] Inside the spin base 21, a chuck pin switching mechanism 23 for switching the positions of a plurality of chuck pins 22 is provided. The chuck pin switching mechanism 23 switches the plurality of chuck pins 22 between a holding position for holding the substrate W and a release position for releasing the holding of the substrate W.

[0028] The rotation mechanism 30 is a mechanism for rotating the substrate holding portion 20. The rotation mechanism 30 is housed inside a motor cover 31 provided below the spin base 21. As shown by the dashed line in FIG. 2, the rotation mechanism 30 has a spin motor 32 and a support shaft 33. The support shaft 33 extends in the vertical direction, the lower end thereof is connected to the spin motor 32, and the upper end thereof is fixed to the center of the lower surface of the spin base 21. When the spin motor 32 is driven, the support shaft 33 rotates about its axis 330. Then, together with the support shaft 33, the substrate holding portion 20 and the substrate W held by the substrate holding portion 20 also rotate about the axis 330.

[0029] The processing liquid supply unit 40 is a mechanism for supplying a processing liquid to the upper surface of the substrate W held by the substrate holding portion 20. The processing liquid supply unit 40 has an upper surface nozzle 41 and a lower surface nozzle 42.

[0030] As shown in FIGS. 1 and 2, the upper surface nozzle 41 has a nozzle arm 411, a nozzle head 412 provided at the tip of the nozzle arm 411, and a nozzle motor 413. The nozzle arm 411 rotates horizontally about the base end portion of the nozzle arm 411 by driving of the nozzle motor 413. Thereby, the nozzle head 412 can be moved between a processing position above the substrate W held by the substrate holding portion 20 (the position of the two-dot chain line in FIG. 1) and a retracted position outside the processing liquid collection unit 50 (the position of the solid line in FIG. 1).

[0031] The nozzle head 412 is connected to a liquid supply section (not shown) for supplying a processing liquid. As the processing liquid, for example, SPM cleaning liquid, SC-1 cleaning liquid, SC-2 cleaning liquid, DHF cleaning liquid (dilute hydrofluoric acid), pure water (deionized water, DIW), IPA (isopropyl alcohol), etc. are used. Note that the SPM cleaning liquid is a mixture of sulfuric acid and hydrogen peroxide solution. The SC-1 cleaning liquid is a mixture of aqueous ammonia, hydrogen peroxide solution, and pure water. The SC-2 cleaning liquid is a mixture of hydrochloric acid, hydrogen peroxide solution, and pure water.

[0032] With the nozzle head 412 placed at the processing position, when the valve of the liquid supply section is opened, the processing liquid supplied from the liquid supply section is discharged from the nozzle head 412 toward the upper surface of the substrate W held by the substrate holding section 20. Note that the nozzle head 412 may be a so-called two-fluid nozzle that mixes the processing liquid and pressurized gas to generate droplets and injects a mixed fluid of the droplets and gas onto the substrate W. Also, a plurality of upper surface nozzles 41 may be provided in one processing unit 102.

[0033] The lower surface nozzle 42 is disposed inside a through hole provided at the center of the spin base 21. The discharge port of the lower surface nozzle 42 faces the lower surface of the substrate W held by the substrate holding section 20. The lower surface nozzle 42 is also connected to a liquid supply section for supplying a processing liquid. When the processing liquid is supplied from the liquid supply section to the lower surface nozzle 42, the processing liquid is discharged from the lower surface nozzle 42 toward the lower surface of the substrate W.

[0034] The processing liquid collection section 50 is a part for collecting the used processing liquid. As shown in FIG. 2, the processing liquid collection section 50 includes an inner cup 51, a middle cup 52, and an outer cup 53. The inner cup 51, the middle cup 52, and the outer cup 53 can move up and down independently of each other by a lifting mechanism (not shown).

[0035] The inner cup 51 has a cylindrical first guide plate 510 that surrounds the periphery of the substrate holding portion 20. The upper part of the first guide plate 510 narrows as it approaches the upper end. The middle cup 52 has a cylindrical second guide plate 520 that surrounds the periphery of the substrate holding portion 20. The upper part of the second guide plate 520 narrows as it approaches the upper end. The second guide plate 520 is located outside and above the first guide plate 510. The outer cup 53 has a cylindrical third guide plate 530 that surrounds the periphery of the substrate holding portion 20. The upper part of the third guide plate 530 narrows as it approaches the upper end. The third guide plate 530 is located outside and above the second guide plate 520.

[0036] The bottom of the inner cup 51 extends below the middle cup 52 and the outer cup 53. And on the upper surface of the bottom, a first drain groove 511, a second drain groove 512, and a third drain groove 513 are provided in order from the inside.

[0037] The processing liquid discharged from the upper nozzle 41 and the lower nozzle 42 of the processing liquid supply unit 40 is supplied to the substrate W, and then scatters outward due to the centrifugal force generated by the rotation of the substrate W. And the processing liquid scattered from the substrate W is collected by any one of the first guide plate 510, the second guide plate 520, and the third guide plate 530.

[0038] When collecting the processing liquid with the first guide plate 510, all of the inner cup 51, the middle cup 52, and the outer cup 53 are arranged at a collection position where their upper ends are located above the substrate W. In this case, the processing liquid scattered outward from the substrate W is collected by the first guide plate 510 and discharged to the outside of the processing unit 102 through the first drain groove 511.

[0039] When collecting the processing liquid with the second guide plate 520, the inner cup 51 is arranged at a standby position (the position shown in FIG. 2) below the substrate W, and the middle cup 52 and the outer cup 53 are arranged at the collection position. In this case, the processing liquid scattered outward from the substrate W is collected by the second guide plate 520 and discharged to the outside of the processing unit 102 through the second drain groove 512.

[0040] When collecting the processing liquid with the third guide plate 530, the inner cup 51 and the middle cup 52 are placed at the standby position, and the outer cup 53 is placed at the collection position. In this case, the processing liquid scattered outward from the substrate W is collected by the third guide plate 530 and discharged to the outside of the processing unit 102 through the third drain groove 513.

[0041] As described above, this processing unit 102 has a plurality of discharge paths for the processing liquid. Therefore, the processing liquid supplied to the substrate W can be separated and collected for each type. Thus, the disposal and regeneration processing of the collected processing liquid can also be performed separately according to the properties of each processing liquid.

[0042] The shielding plate 60 is a member for suppressing the diffusion of gas in the vicinity of the surface of the substrate W when performing some processes such as drying. The shielding plate 60 has a disc-shaped outer shape and is horizontally arranged above the substrate holding portion 20. As shown in FIG. 2, the shielding plate 60 is connected to the lifting mechanism 61. When the lifting mechanism 61 is operated, the shielding plate 60 moves up and down between an upper position away from the upper surface of the substrate W held by the substrate holding portion 20 and a lower position closer to the upper surface of the substrate W than the upper position. For the lifting mechanism 61, for example, a mechanism that converts the rotational motion of a motor into a linear motion by a ball screw is used.

[0043] In addition, a blowout port 62 for blowing out drying gas is provided at the center of the lower surface of the shielding plate 60. Hereinafter, the gas discharged from the blowout port 62 is referred to as "drying gas". The blowout port 62 is connected to a gas supply portion (not shown) that supplies the drying gas. For the drying gas, for example, heated nitrogen gas is used.

[0044] When supplying the processing liquid to the substrate W from the upper nozzle 41, the shielding plate 60 retracts to the upper position. After the supply of the processing liquid, when performing the drying process on the substrate W, the shielding plate 60 descends to the lower position by the lifting mechanism 61. Then, the drying gas is blown toward the upper surface of the substrate W from the blowout port 62. At this time, the shielding plate 60 prevents the diffusion of gas. As a result, the drying gas is efficiently supplied to the upper surface of the substrate W.

[0045] The camera 70 is a device that captures specific operations within the chamber 10. The camera 70 is installed, for example, at a position close to the inner surface of the side wall 12 of the chamber 10. The camera 70 is a high-speed frame-based camera. Therefore, the video data (video images) output by the camera 70 is a series of frame images with information on the luminance values of a large number of pixels arranged in time series. The camera 70 transmits the video data E obtained by shooting to the control unit 80.

[0046] FIG. 3 is a diagram conceptually showing the state of shooting by the camera 70. In the present embodiment, among the upper surface of the substrate W supported by the spin base 21, the observation target area including the end portion of the substrate W is set to be included in the shooting area A of the camera 70. When performing an operation of discharging the processing liquid from the nozzle head 412 onto the surface of the substrate W, or when performing a drying operation of the substrate W, the camera 70 shoots the operation within the shooting area A. In the example of FIG. 3, not all of the upper surface of the substrate W is included in the shooting area A, but it may be set such that all of the upper surface of the substrate W is included in the shooting area A.

[0047] The control unit 80 is a means for controlling the operation of each part within the processing unit 102. FIG. 4 is a block diagram showing the electrical connection between the control unit 80 and each part within the processing unit 102. As conceptually shown in FIG. 4, the control unit 80 is composed of a computer having a processor 81 such as a CPU, a memory 82 such as a RAM, and a storage unit 83 such as a hard disk drive.

[0048] Stored in the storage unit 83 are an operation control program P1 and a liquid film state analysis program P2. The operation control program P1 is a computer program for controlling the operation of each part of the processing unit 102 in order to execute the processing of the substrate W in the processing unit 102. The liquid film state analysis program P2 is a computer program for analyzing and evaluating the liquid film state on the substrate W based on the video data E obtained from the camera 70.

[0049] As shown in FIG. 4, the control unit 80 is communicably connected to the above-described chuck pin switching mechanism 23, spin motor 32, nozzle motor 413, valve of the processing liquid supply unit 40, lifting mechanism of the processing liquid collection unit 50, lifting mechanism 61 of the shutter plate 60, and camera 70, respectively, by wire or wirelessly. Further, the control unit 80 is also electrically connected to a display unit 84 such as a liquid crystal display and an input unit 85. The control unit 80 controls the operation of each of the above units based on the operation control program P1 and the liquid film state analysis program P2 stored in the storage unit 83.

[0050] <3. Operation of the Substrate Processing Apparatus> Next, the processing of the substrate W in the above processing unit 102 will be described. FIG. 5 is a flowchart showing the flow of the cleaning process (step S100) of the substrate W. This cleaning process (S100) is realized by the processor 81 operating according to the operation control program P1 stored in the storage unit 83.

[0051] When processing the substrate W in the processing unit 102, first, the main transfer robot 103 transfers the substrate W to be processed into the chamber 10 (step S101). The substrate W transferred into the chamber 10 is horizontally held by the plurality of chuck pins 22 of the substrate holding unit 20. Thereafter, the rotation of the substrate W is started by driving the spin motor 32 of the rotation mechanism 30 (step S102). Specifically, the support shaft 33, spin base 21, plurality of chuck pins 22, and the substrate W held by the chuck pins 22 rotate about the axis 330 of the support shaft 33.

[0052] Subsequently, the processing liquid is supplied from the processing liquid supply unit 40 (step S103). In step S103, by driving the nozzle motor 413, the nozzle head 412 moves to the processing position facing the upper surface of the substrate W. Then, the processing liquid is discharged from the nozzle head 412 disposed at the processing position toward the center of the upper surface of the substrate W. Parameters such as the discharge speed and discharge time of the processing liquid are preset in the storage unit 83 in the control unit 80. The control unit 80 executes the discharge operation of the processing liquid from the upper surface nozzle 41 according to the setting.

[0053] In step S103, a plurality of processing liquids are sequentially supplied to the upper surface of the substrate W. When the processing liquid to be supplied is switched, before the supply of the previously supplied processing liquid is completed, the supply of the next processing liquid to be supplied starts. That is, when the processing liquid to be supplied is switched, two types of processing liquids are temporarily supplied simultaneously. In step S103, while discharging the processing liquid from the upper surface nozzle 41, the upper surface nozzle 41 may be swung horizontally at the processing position. Further, if necessary, the processing liquid may be discharged from the lower surface nozzle 42.

[0054] During the processing liquid supply step of step S103, the shutter 60 is disposed at the upper position above the upper surface nozzle 41. When the supply of the processing liquid to the substrate W is completed and the upper surface nozzle 41 is disposed at the retracted position, the control unit 80 operates the elevating mechanism 61 to move the shutter 60 from the upper position to the lower position. Then, the rotation speed of the spin motor 32 is increased to increase the rotation speed of the substrate W, and drying gas is blown from the air outlet 62 provided on the lower surface of the shutter 60 toward the substrate W. Thereby, the surface of the substrate W is dried (step S104).

[0055] When the drying process of the substrate W is completed, the spin motor 32 is stopped to stop the rotation of the substrate W. Then, the holding of the substrate W by the plurality of chuck pins 22 is released. Thereafter, the main transfer robot 103 takes out the processed substrate W from the substrate holding unit 20 and carries it out of the chamber 10 (step S105).

[0056] Each processing unit 102 repeatedly executes the processes of steps S101 to S105 described above for a plurality of substrates W sequentially conveyed.

[0057] <4. Analysis and Evaluation of Liquid Film State> Subsequently, the analysis and evaluation of the liquid film state of the substrate W in the substrate processing apparatus 100 will be described. Hereinafter, the standard trend acquisition process (S200) performed prior to the analysis and evaluation process and the analysis and evaluation process (S300) of the liquid film state in the processing liquid supply step (S103) will be described.

[0058] These standard trend acquisition process (S200) and analysis and evaluation process of the liquid film state (S300) are realized by the processor 81 operating according to the liquid film state analysis program P2 stored in the storage unit 83.

[0059] FIG. 6 is a functional block diagram of the control unit 80. As shown in FIG. 6, the control unit 80 includes a data acquisition unit 801, a calculation unit 802, and an analysis / evaluation unit 803 as functional units based on the liquid film state analysis program P2.

[0060] The data acquisition unit 801 acquires video data E obtained by photographing the liquid film on the upper surface of the substrate W from the camera 70 and displays it on the display unit 84. Further, the data acquisition unit 801 acquires the range of the ROI (region of interest) in the video data E from the input unit 85. The calculation unit 802 calculates the luminance, non-uniformity, statistical amount of luminance, and statistical amount of non-uniformity of the ROI for each frame image F of the video data E. The analysis / evaluation unit 803 analyzes and evaluates the state of the liquid film on the upper surface of the substrate W based on each value calculated by the calculation unit 802.

[0061] FIG. 7 is a flowchart showing the flow of the standard trend acquisition process (step S200). The standard trend acquisition process shown in FIG. 7 is performed prior to the analysis and evaluation process of the liquid film state shown in FIG. 10.

[0062] In the standard trend acquisition process (S200), first, the data acquisition unit 801 performs shooting of the process liquid supply step (S103) by the camera 70 on a plurality of substrates W for the processing unit 102 to be evaluated (step S201). The camera 70 transmits the obtained moving image data E to the control unit 80. As a result, the data acquisition unit 801 acquires a plurality of moving image data E.

[0063] Subsequently, the data acquisition unit 801 displays the acquired moving image data E on the display unit 84. Then, for the moving image data E displayed on the display unit 84, the user sets an ROI (region of interest) at the input unit 85 and inputs it to the data acquisition unit 801 (step S202). In step S202, an ROI may be set for each of all the moving image data E, or an ROI common to a plurality of moving image data E may be set.

[0064] FIG. 8 is an image diagram showing an example of a plurality of frame images F included in the moving image data E. In the frame image F of FIG. 8, a part of the upper surface of the substrate W including the end portion of the disk-shaped substrate W is photographed. FIG. 9 is an image diagram showing the ROI set in the frame image F of FIG. 8. In FIG. 9, the ROI is indicated by a white frame and white diagonal lines. In FIG. 9, a region near the end of the substrate W is set as the ROI.

[0065] Next, the calculation unit 802 acquires the luminance value of each pixel of the ROI for each of the frame images F included in the moving image data E, and calculates a first statistic (step S203). The first statistic is the average luminance value obtained by averaging the luminance values of the entire ROI and the average non-uniformity value obtained by averaging the non-uniformity of the luminance values of the entire ROI. One value of the average luminance value and the average non-uniformity value is calculated for each of the frame images F. Therefore, the average luminance value and the average non-uniformity value each become one time-series data for one moving image data E.

[0066] The non-uniformity of the luminance value is specifically calculated from the luminance values of an n×n region centered on each pixel of the ROI. The n×n region is, for example, 3×3 or 5×5. The non-uniformity is calculated, for example, by calculating the GLCM (Gray-Level Co-occurrence Matrix) to normalize the image, and then calculating the non-uniformity (dissimilarity) for each pixel of the ROI. The average non-uniformity value is calculated by averaging the non-uniformity values of the entire ROI calculated in this way.

[0067] Thereafter, the calculation unit 802 calculates at least one of the second statistics based on the time-series data of the first statistics of the moving image data E (step S204). The second statistics include at least one of the luminance statistic, which is the statistic of the average luminance value of the ROI, and the non-uniformity statistic, which is the statistic of the average non-uniformity value of the ROI.

[0068] The luminance statistic includes, for example, the luminance moving average, which is the moving average of the average luminance value for each period of a predetermined length (for example, every 40 frames), and the luminance standard deviation, which is the standard deviation of the average luminance value for each period of a predetermined length (for example, every 40 frames). The non-uniformity statistic includes, for example, the non-uniformity moving average, which is the moving average of the average non-uniformity value for each period of a predetermined length (for example, every 40 frames), the non-uniformity standard deviation, which is the standard deviation of the average non-uniformity value for each period of a predetermined length (for example, every 40 frames), the non-uniformity moving average derivative value, which is the first derivative of the non-uniformity moving average, and the moving average of the non-uniformity moving average derivative value.

[0069] The calculation unit 802 stores the first statistics and the second statistics obtained and calculated in steps S203 and S204 in the storage unit 83 as the standard trends D of the respective values (step S205). It should be noted that the moving image data E input in step S201 to obtain the standard trend D is preferably the moving image data E of the substrate W that has been determined to have appropriate cleaning and drying processes as a result. In this way, in the subsequent step S300, by comparing the moving image data E to be analyzed with the standard trend D of only good products, the accuracy of the analysis and evaluation of whether the process of the substrate W captured in the moving image data E to be analyzed is appropriate is improved.

[0070] Figure 10 is a flowchart showing the flow of the analysis / evaluation process (step S300) of the liquid film state. In the analysis / evaluation process (step S300) of the liquid film state, first, the data acquisition unit 801 captures an image of the processing liquid supply step (S103) by the camera 70 for the substrate W to be evaluated (step S301). The camera 70 transmits the obtained moving image data E to the control unit 80. As a result, the data acquisition unit 801 acquires a plurality of moving image data E.

[0071] Subsequently, the data acquisition unit 801 displays the acquired moving image data E on the display unit 84. Then, for the moving image data E displayed on the display unit 84, the user sets an ROI (region of interest) at the input unit 85 and inputs it to the data acquisition unit 801 (step S302). In the case where an ROI common to a plurality of moving image data E is set in step S202 of the standard trend acquisition process (S200), the same ROI may be used in step S302.

[0072] Next, for each frame image F included in the moving image data E, the calculation unit 802 acquires the luminance value of each pixel of the ROI and calculates the luminance average value and the non-uniformity average value, which are the first statistical quantities (step S303). After that, in the same manner as in step S204, the calculation unit 802 calculates at least one of the luminance statistic and the non-uniformity statistic as the second statistical quantity for each of the moving image data E (step S304).

[0073] The calculation unit 802 analyzes the first statistical quantity and the second statistical quantity acquired and calculated in steps S303 and S304 (step S305). Specifically, it compares with the standard trend D of each value stored in the storage unit 83, or analyzes whether each value is within the standard range using a threshold value calculated based on the standard trend D. Then, based on the analysis result of step S305, the calculation unit 802 evaluates whether the state of the liquid film on the substrate W is appropriate (step S306).

[0074] FIG. 11 is a diagram showing an example of time-series data of the first statistic and the second statistic obtained and calculated in steps S304 and S305. The upper part of FIG. 11 shows the average luminance value (gray) and the moving average of the luminance, which is the luminance moving average (black). The middle part of FIG. 11 shows the average non-uniformity value (gray) and the moving average of the non-uniformity, which is the non-uniformity moving average (black). The lower part of FIG. 11 shows the differential value of the non-uniformity moving average (gray) and its moving average (black). FIG. 11 shows each value in the first state, the transition period during which the state of the supply liquid changes from the first state to the second state, and the subsequent second state in the processing liquid supply step (S103).

[0075] The transition from the first state to the second state is, for example, a change in flow rate, a change in the discharge nozzle, a change in the discharged liquid (including a change in the discharge nozzle), etc. Therefore, when changing the flow rate, the transition period is the period from the start of the flow rate change to the end of the change. Also, when changing the discharge nozzle or the discharged liquid involving a change in the discharge nozzle, the first state is the period during which discharge is performed only from the first nozzle, the transition period is the period during which discharge from the second nozzle is started and discharge is performed from both the first nozzle and the second nozzle, and then the second state is reached by stopping the discharge from the first nozzle. And after the second state is reached from the transition period, the time point when the state of the liquid surface becomes stable is referred to as the switching completion time.

[0076] In the data of FIG. 11, time t1 is the start time of the transition period, and time t2 is the end time of the transition period (start time of the second state). That is, from the start of the data in FIG. 11 to time t1, it is the first state. From time t1 to time t2, it is the transition period. After time t2, it is the second state. Also, time t4 is the switching completion time when the state of the liquid surface becomes stable after the second state is reached from the transition period.

[0077] The average luminance value is stable in the first state (before time t1). During the transition period (time t1 to t2), although there is a slight decrease in the average luminance value, no significant change is observed. After that, when it enters the second state (after time t2), the average luminance value rises while fluctuating up and down, and after time t4, it stabilizes at a value higher than that in the first liquid supply state (before time t1).

[0078] Looking at the moving average of the luminance value, which is the moving average of the average luminance value, two downward peaks and one upward peak are observed at times t1 to t4.

[0079] On the other hand, although the non-uniformity is stable in the first state (before time t1), a decrease is observed in the two-liquid supply state (time t1 to t2). After that, when it enters the second state (after time t2), it decreases while fluctuating, and after time t4, it stabilizes at a value lower than that in the first state (before time t1).

[0080] Looking at the moving average of the non-uniformity, which is the moving average of the non-uniformity, two downward peaks and two upward peaks are observed at times t1 to t4.

[0081] Also, the differential value of the moving average of the non-uniformity, which is the first derivative of the moving average of the non-uniformity, is stable near 0 both in the first state (before time t1) and after time t4. On the other hand, significant fluctuations are observed in the differential value of the moving average of the non-uniformity between the transition period (time t1 to t2) and before time t4 in the second state (after time t2).

[0082] In particular, the moving average of the differential value of the moving average of the non-uniformity does not fall below the negative first threshold value T1 shown by the dotted line both in the first state (before time t1) and after time t4. Also, looking at the moving average of the differential value of the moving average of the non-uniformity, three downward peaks and two upward peaks are observed at times t1 to t4.

[0083] In the substrate processing apparatus 100 of the present embodiment, when transitioning from the first state to the second state, the above tendency was observed for the ROI of all video data E for the substrate W that is a good product. In the actual video data E, since it is difficult to match which frames of the video data E the times t1 and t2 correspond to, the state switching period can be calculated by the following method.

[0084] The moving average of the non-uniformity moving average differential value is after the time t1 and below the first threshold value T1 having the above negative value at a time closer to the time t1 than the time t2. Therefore, the time t2 when the moving average of the non-uniformity moving average differential value falls below the first threshold value T1 is set as the switching start time t2. Note that the first threshold value T1 and the second threshold value T2 described later may be stored in the storage unit 83 in advance.

[0085] Also, the moving average of the non-uniformity moving average differential value stabilizes near 0 after becoming 0 or more after three downward peaks after the time t2. Therefore, the time t4 when the time t2 is exceeded after showing a negative peak a predetermined number of times (three times) and exceeding the second threshold value T2 = 0 is set as the switching completion time t4. Since both the luminance average value and the non-uniformity maintain stable values after the time t4 calculated in this way, it is considered that the state of the liquid film is stable.

[0086] Using such trends of the calculated values, the state of the liquid film on the substrate W can be quantitatively analyzed. And the evaluation of the liquid film state in the same process can be performed.

[0087] When evaluating the liquid film state in the same process, in the analysis step of step S305, the calculated values are compared for the video data E of the substrate W to be analyzed and the standard trend D of only good products. And, for example, those in which the peak value of the luminance value moving average or the non-uniformity moving average is significantly different from the standard trend D are evaluated as having a high possibility of a defective liquid film state in the evaluation step of step S306.

[0088] Although not shown in FIG. 11, in the analysis step of step S305, even for those with significantly different luminance standard deviation and non-uniformity standard deviation from the standard trend D, in the evaluation step of step S306, it is highly likely that the liquid film state is defective.

[0089] Also, when changing the amount of chemical solution to be supplied or the rotation speed of the substrate W, the liquid film state can be evaluated in different processes.

[0090] As an example, for instance, evaluation can be performed by comparing the state switching times. In that case, in the analysis step of step S305, using the above method, the time t2 and the time t4 are calculated from the moving average of the moving average differential value of the non-uniformity, and the period from time t2 to t4 is calculated as the state switching time. And when the calculated state switching time is longer than the standard trend D representing the conventional process, in the evaluation step of step S306, it is evaluated that the switching of the liquid is not smooth. On the other hand, when the calculated state switching time is shorter than the standard trend D, in the evaluation step of step S306, it is evaluated that the switching from the first state to the second state is smooth.

[0091] Also, as another example, for instance, evaluation can be performed by comparing each statistic within the state switching time. In that case, in the analysis step of step S305, when the standard deviation of the luminance value or the standard deviation of the non-uniformity is significantly larger than the standard deviation in the standard trend D, it may be evaluated that there is a possibility of exposure of the substrate W occurring during the switching from the first state to the second state.

[0092] <5. Modification Example> As described above, one embodiment of the present invention has been described, but the present invention is not limited to the above embodiment.

[0093] In the above-described embodiment, the movement of the values used for analysis and evaluation and the values of each value regarding the switching from a specific first state to a second state have been described. However, the present invention is not limited to this. The switching from the first state to the second state may be any state switching such as a change in flow rate, a change in the discharge nozzle, a change in the discharged liquid (including a change in the discharge nozzle). In that case, the behavior of each value is different from that described above. Therefore, after grasping the typical behavior of each value by the standard trend acquisition process (S200), the liquid film state analysis / evaluation process (S300) can be appropriately performed to analyze and evaluate the liquid film state.

[0094] Also, in the above-described embodiment, a specific operation has been photographed in one of the plurality of processing units 102, and the state of the liquid film of the supply liquid for each substrate W has been analyzed and evaluated. However, in the plurality of processing units 102, the same liquid supply process may be photographed a plurality of times, the standard trend D may be acquired based on the obtained moving image data E, and it may be used for evaluation.

Explanation of Reference Numerals

[0095] 80: Control Unit 801: Data Acquisition Unit 802: Calculation Unit 803: Evaluation Unit D: Standard Trend E: Moving Image Data F: Frame Image P2: Liquid Film State Analysis Program T1: First Threshold T2: Second Threshold W: Substrate t2: Switching Start Time t4: Switching Completion Time

Claims

1. In a substrate processing apparatus, an analysis method for analyzing the state of a liquid film on a rotating substrate supplied with a liquid, comprising: a) obtaining the luminance value of each pixel in a predetermined region from an image of the surface of the substrate, and calculating a first statistic from the luminance values; b) calculating a second statistic that is a statistic of the time-series data of the first statistic; c) analyzing the state of the liquid film on the substrate based on at least one of the first statistic and the second statistic; wherein the first statistic includes a luminance average value obtained by averaging the luminance values of the region, and a non-uniformity average value obtained by averaging the non-uniformity of the luminance values of the region; and the second statistic includes a luminance statistic that is a statistic of the time-series data of the luminance average value, and a non-uniformity statistic that is a statistic of the time-series data of the non-uniformity average value; An analysis method comprising at least one of the above.

2. The analysis method according to claim 1, wherein the luminance statistic includes a luminance standard deviation value that is the standard deviation of the luminance values of the entire region. An analysis method comprising the above.

3. The analysis method according to claim 1, wherein the non-uniformity statistic includes a non-uniformity standard deviation that is the standard deviation of the non-uniformity of the entire region. An analysis method comprising the above.

4. The analysis method according to claim 1, wherein the non-uniformity statistic includes a non-uniformity differential moving average that is the moving average of the first derivative of the moving average of the non-uniformity average value obtained by averaging the non-uniformity of the entire region. An analysis method comprising the above.

5. The analysis method according to claim 1, wherein the non-uniformity statistic includes a non-uniformity differential moving average that is the moving average of the first derivative of the moving average of the non-uniformity average value obtained by averaging the non-uniformity of the entire region; and in step a), the image is taken in a first state, a transition period from the first state to a second state, and the second state, and in step c), at the second state, the switching completion time when the liquid film on the substrate stabilizes is analyzed based on the non-uniformity differential moving average.

6. The analysis method according to claim 5, wherein the non-uniformity statistic includes a non-uniformity moving average differential value that is the first derivative of the moving average of the non-uniformity average value obtained by averaging the non-uniformity of the entire region, and a moving average of the non-uniformity moving average differential value; and in step c), the time when the moving average of the non-uniformity moving average differential value falls below a first threshold value that is a predetermined negative value is set as the start time of the transition period. An analysis method in which the time when the moving average of the unevenness moving average differential value exceeds a second threshold value after showing negative peaks a predetermined number of times is defined as the switching completion time.

7. An evaluation method for analyzing and evaluating the state of a liquid film on a rotating substrate in a substrate processing apparatus, the method comprising: p) obtaining the luminance value of each pixel from a predetermined region of an image obtained by imaging the surface of each substrate when the same process is performed on a plurality of the substrates, and calculating a first statistic from the luminance values; q) calculating a second statistic that is a statistic of the time-series data of the first statistic; r) analyzing and evaluating the state of the liquid film on the substrate based on at least one of the first statistic and the second statistic; comprising: The first statistic is: the average luminance value obtained by averaging the luminance values of the region; the average unevenness value obtained by averaging the unevenness of the luminance values of the region; including: The second statistic is: a luminance statistic that is a statistic of the time-series data of the average luminance value; an unevenness statistic that is a statistic of the time-series data of the average unevenness value; An evaluation method including at least one of them.

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