Parameter optimization device and parameter optimization method

Abstract

To provide a technique capable of appropriately optimizing parameters using a measured film thickness distribution.SOLUTION: A control unit 9 comprises a film thickness distribution acquisition section 911, an edge cut width setting section 913, a feature quantity calculation section 915, a cost value calculation section 917, and a parameter determination section 919. The film thickness distribution acquisition section 911 acquires a film thickness distribution of a coating film formed on a substrate S. The edge cut width setting section 913 sets an edge cut width WE, which is a width dimension of an edge cut region AE extending inward from an end of the substrate S. The feature quantity calculation section 915 calculates a feature quantity F of a film thickness distribution TTD in a target region AT, which is a region on an upper surface Sf of the substrate S excluding the edge cut region AE, using a variation amount from a film thickness representative value. The cost value calculation section 917 calculates a cost value using the feature quantity F. The parameter determination section 919 determines a control parameter on the basis of the cost value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The subject matter disclosed herein relates to a parameter optimization apparatus and a parameter optimization method. [Background technology]

[0002] In the manufacturing process of flat panel displays, a device called a coater is used. A coater is a substrate processing device that uses a pump to eject a processing liquid from a slit nozzle and apply the processing liquid to the entire substrate being transported. In recent years, with the trend toward higher product quality, coaters are being required to apply the processing liquid so that the film thickness of the processing liquid is uniform across the entire substrate.

[0003] For example, Patent Document 1 discloses that the parameters for controlling a pump are adjusted and optimized by repeatedly measuring the discharge characteristics when a treatment liquid is discharged. Also, Patent Document 2 discloses that a feature amount is calculated from a discharge pressure waveform and the discharge pressure waveform is evaluated based on this feature amount. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-040046 [Patent Document 2] Japanese Patent Publication No. 2022-138109 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the prior art does not take into consideration the optimization of parameters based on the film thickness distribution of the coating film actually formed on the substrate.

[0006] An object of the present invention is to provide a technique that can appropriately optimize parameters using a measured film thickness distribution. [Means for solving the problem]

[0007] In order to solve the above problem, a first aspect is a parameter optimization device that optimizes parameters used in a coating process that applies a processing liquid to a substrate, and includes a film thickness distribution acquisition unit that acquires the film thickness distribution of a coating film formed on the substrate, an edge cut width setting unit that sets the edge cut width, which is the width dimension of an edge cut region that extends inward from the edge of the substrate, a feature calculation unit that calculates a feature indicating the amount of change from a representative film thickness value for the film thickness distribution in a target region on the surface of the substrate excluding the edge cut region, a cost value calculation unit that calculates a cost value using the feature value, and a parameter determination unit that determines the parameters based on the cost value.

[0008] A second aspect is the parameter optimization device of the first aspect, wherein an upper threshold value greater than the film thickness representative value and a lower threshold value smaller than the film thickness representative value are set in advance, and the feature amount calculation unit calculates the feature amount using the amount of change and an excess amount when the film thickness distribution exceeds the upper threshold value or the lower threshold value.

[0009] A third aspect is a parameter optimization device according to the first or second aspect, wherein the edge cut width setting unit is capable of setting a plurality of different edge cut widths, the feature amount calculation unit calculates the feature amount from the film thickness distribution for each target area of ​​the substrate excluding areas of the plurality of edge cut widths, and the cost value calculation unit calculates the cost value using the feature amount for each target area.

[0010] A fourth aspect is the parameter optimization device according to the third aspect, wherein the cost value calculation unit calculates the cost value using a weighted sum obtained by weighting and adding the feature amounts for each edge cut width.

[0011] A fifth aspect is a parameter optimization method for optimizing parameters used in a coating process for applying a processing liquid to a substrate, and includes the steps of: a) acquiring a film thickness distribution of a coating film formed on a substrate; b) setting an edge cut width, which is the width dimension of an edge cut region extending inward from an edge of the substrate; c) calculating a feature value indicating the amount of change from a representative film thickness value for the film thickness distribution in a target region on the surface of the substrate excluding the edge cut region; d) calculating a cost value using the feature value; and e) determining the parameters based on the cost value.

[0012] A sixth aspect is a computer program executable by a computer, causing the computer to execute the parameter optimization method of the fifth aspect. [Effects of the Invention]

[0013] According to the first to sixth aspects, the uniformity of the film thickness distribution can be appropriately quantified by calculating a feature value indicating the amount of change from a representative film thickness value, thereby enabling the parameters used in the coating process to be appropriately optimized based on the film thickness distribution.

[0014] According to the parameter optimization device of the second aspect, the degree of abnormality in the film thickness distribution can be reflected in the feature amount by adding the excess amount when the threshold is exceeded to the feature amount.

[0015] According to the parameter optimization device of the third aspect, it is possible to calculate a cost value by integrating feature amounts calculated with different edge cut widths.

[0016] According to the parameter optimization device of the fourth aspect, the importance of each edge cut width can be reflected in the cost value. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram schematically illustrating an overall configuration of a coating apparatus according to an embodiment. [Figure 2]2 is a diagram showing the configuration of a treatment liquid supply mechanism included in the coating apparatus shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control unit. [Figure 4] FIG. 2 is a top view showing the top surface of the substrate. [Figure 5] FIG. 4 is a diagram showing an example of a film thickness distribution acquired by a film thickness distribution acquisition unit. [Figure 6] FIG. 10 is a diagram conceptually illustrating an example of calculating a feature amount from a target membrane pressure distribution. [Figure 7] FIG. 10 is a diagram illustrating the relationship between the edge cut width and the feature amount. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the components described in the embodiment are merely examples and are not intended to limit the scope of the present invention. In the drawings, the dimensions and numbers of each part may be exaggerated or simplified as necessary to facilitate understanding.

[0019] <1. Embodiment> 1 is a diagram schematically illustrating the overall configuration of a coating apparatus 1 according to an embodiment. The coating apparatus 1 is a substrate processing apparatus that forms a coating film on the substrate S by discharging a processing liquid onto the upper surface Sf of the substrate S. As will be described later, the coating apparatus 1 has a control unit 9. The control unit 9 functions as a parameter optimization device that optimizes parameters for controlling the discharge of the processing liquid.

[0020] The substrate S is, for example, a glass substrate for a liquid crystal display device. The substrate S may also be a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a plasma display, a glass or ceramic substrate for a magnetic or optical disk, a glass substrate for an organic EL display, a glass or silicon substrate for a solar cell, or any other substrate to be processed for electronic devices such as a flexible substrate or a printed circuit board. The coating device 1 is, for example, a slit coater.

[0021] In FIG. 1, an XYZ coordinate system is defined to explain the positional relationship of each element of the coating apparatus 1. The transport direction of the substrate S is the "X direction." The direction in which the substrate S advances in the X direction (toward downstream in the transport direction) is the +X direction, and the opposite direction (toward upstream in the transport direction) is the -X direction. The direction perpendicular to the X direction is the Y direction, and the direction perpendicular to the X and Y directions is the Z direction. In the following description, the Z direction is the vertical direction, and the X and Y directions are the horizontal directions. In the Z direction, the +Z direction is the upward direction, and the -Z direction is the downward direction. Note that these directions are not intended to limit the arrangement of the coating apparatus.

[0022] The coating apparatus 1 includes, in order in the +X direction, an input conveyor 100, an input transfer unit 2, a floating stage unit 3, an output transfer unit 4, and an output conveyor 110. The input conveyor 100, the input transfer unit 2, the floating stage unit 3, the output transfer unit 4, and the output conveyor 110 form a transport path along which the substrate S passes. The coating apparatus 1 also includes a substrate transport unit 5, a coating mechanism 7, a treatment liquid supply mechanism 8, and a control unit 9.

[0023] The substrate S is transported to the input conveyor 100 from a device upstream of the coating device 1. The input conveyor 100 includes a roller conveyor 101 and a rotation drive mechanism 102. The rotation drive mechanism 102 rotates each roller of the roller conveyor 101. Due to the rotation of each roller of the roller conveyor 101, the substrate S is transported downstream (+X direction) in a horizontal position. The "horizontal position" refers to a state in which the main surface (the surface with the largest area) of the substrate S is parallel to the horizontal plane (XY plane).

[0024] The input transfer section 2 is equipped with a roller conveyor 21 and a rotation / lifting drive mechanism 22. The rotation / lifting drive mechanism 22 rotates each roller of the roller conveyor 21 and raises and lowers the roller conveyor 21. The rotation of the roller conveyor 21 transports the substrate S downstream (+X direction) in a horizontal position. The elevation of the roller conveyor 21 also changes the position of the substrate S in the Z direction. The substrate S is transferred from the input conveyor 100 to the floating stage section 3 via the input transfer section 2.

[0025] As shown in FIG. 1 , the floating stage unit 3 is substantially flat. The floating stage unit 3 is divided into three sections along the X direction. The floating stage unit 3 includes, in order along the +X direction, an entrance floating stage 31, a coating stage 32, and an exit floating stage 33. The upper surfaces of the entrance floating stage 31, the coating stage 32, and the exit floating stage 33 are on the same plane. The floating stage unit 3 further includes a lift pin drive mechanism 34, a floating control mechanism 35, and an elevation drive mechanism 36. The lift pin drive mechanism 34 raises and lowers the multiple lift pins arranged on the entrance floating stage 31. The floating control mechanism 35 supplies compressed air to the entrance floating stage 31, the coating stage 32, and the exit floating stage 33 to float the substrate S. The elevation drive mechanism 36 raises and lowers the exit floating stage 33.

[0026] A large number of nozzle holes for ejecting compressed air supplied from the levitation control mechanism 35 are arranged in a matrix on the upper surface of the entrance levitation stage 31 and the upper surface of the exit levitation stage 33. When compressed air is ejected from each nozzle hole, the substrate S is levitated upward relative to the levitation stage part 3. As a result, the lower surface Sb of the substrate S is separated from the upper surface of the levitation stage part 3, and the substrate S is supported in a horizontal position. When the substrate S is in a levitated state, the distance (levitation amount) between the lower surface Sb of the substrate S and the upper surface of the levitation stage part 3 is, for example, 10 μm or more and 500 μm or less.

[0027] The upper surface of the coating stage 32 is provided with jet holes for jetting compressed air supplied from the levitation control mechanism 35 and suction holes for sucking gas. The jet holes and suction holes are arranged alternately in the X and Y directions. The levitation control mechanism 35 controls the amount of compressed air jetted from the jet holes and the amount of air sucked from the suction holes. This precisely controls the amount of levitation of the substrate S relative to the coating stage 32 so that the position in the Z direction of the upper surface Sf of the substrate S passing above the coating stage 32 is a specified value. The levitation amount of the substrate S relative to the coating stage 32 is calculated by the control unit 9 based on the detection results of a sensor 61 or a sensor 62, which will be described later. The levitation amount of the substrate S relative to the coating stage 32 is preferably adjustable with high precision by airflow control.

[0028] The substrate S carried into the floating stage unit 3 is imparted with a propulsive force in the +X direction by the roller conveyor 21, and is transported onto the entrance floating stage 31. The entrance floating stage 31, the coating stage 32, and the exit floating stage 33 support the substrate S in a floating state. For example, the configuration described in Japanese Patent No. 5346643 can be used as the floating stage unit 3.

[0029] The substrate transport unit 5 is disposed below the floating stage unit 3. The substrate transport unit 5 includes a chuck mechanism 51 and a suction / travel control mechanism 52. The chuck mechanism 51 includes a suction pad (not shown) provided on a suction member. The chuck mechanism 51 supports the substrate S from below by bringing the suction pad into contact with the peripheral edge of the lower surface Sb of the substrate S. The suction / travel control mechanism 52 applies negative pressure to the suction pad, thereby suctioning the substrate S to the suction pad. The suction / travel control mechanism 52 also causes the substrate transport unit 5 to travel back and forth in the X direction.

[0030] The chuck mechanism 51 holds the substrate S in a state where the lower surface Sb of the substrate S is positioned higher than the upper surface of the floating stage part 3. With the peripheral edge of the substrate S held by the chuck mechanism 51, the buoyancy applied by the floating stage part 3 keeps the substrate S in a horizontal position.

[0031] 1, the coating device 1 includes a sensor 61 for measuring plate thickness. The sensor 61 is disposed near the roller conveyor 21. The sensor 61 detects the position in the Z direction of the upper surface Sf of the substrate S held by the chuck mechanism 51. Furthermore, a chuck (not shown) that is not holding the substrate S is positioned directly below the sensor 61, so that the sensor 61 can detect the position in the vertical direction Z of the suction surface, which is the upper surface of the suction member.

[0032] The chuck mechanism 51 moves in the +X direction while holding the substrate S that has been carried into the floating stage section 3. As a result, the substrate S is transported from above the entrance floating stage 31, via above the coating stage 32, to above the exit floating stage 33. Then, the substrate S is moved from the exit floating stage 33 to the output transfer section 4.

[0033] The output transfer unit 4 moves the substrate S from a position above the exit floating stage 33 to the output conveyor 110. The output transfer unit 4 includes a roller conveyor 41 and a rotation / lifting drive mechanism 42. The rotation / lifting drive mechanism 42 drives the roller conveyor 41 to rotate and also raises and lowers the roller conveyor 41 in the Z direction. As each roller of the roller conveyor 41 rotates, the substrate S moves in the +X direction. Furthermore, as the roller conveyor 41 rises and falls, the substrate S is displaced in the Z direction.

[0034] The output conveyor 110 includes a roller conveyor 111 and a rotation drive mechanism 112. The output conveyor 110 transports the substrate S in the +X direction by the rotation of each roller of the roller conveyor 111, and delivers the substrate S to the outside of the coating apparatus 1. The input conveyor 100 and the output conveyor 110 are part of the coating apparatus 1. However, the input conveyor 100 and the output conveyor 110 may be incorporated into a device separate from the coating apparatus 1.

[0035] The coating mechanism 7 coats the upper surface Sf of the substrate S with a processing liquid. The coating mechanism 7 is disposed above the transport path of the substrate S. The coating mechanism 7 has a nozzle 71. The nozzle 71 is a slit nozzle having a slit-shaped outlet on its lower surface. The nozzle 71 is connected to a positioning mechanism (not shown). The positioning mechanism moves the nozzle 71 between a coating position above the coating stage 32 (the position indicated by the solid line in FIG. 1) and a maintenance position, which will be described later. The processing liquid supply mechanism 8 is connected to the nozzle 71. The processing liquid supply mechanism 8 supplies the processing liquid to the nozzle 71, causing the processing liquid to be ejected from an outlet disposed on the lower surface of the nozzle 71.

[0036] FIG. 2 is a diagram showing the configuration of a treatment liquid supply mechanism 8 included in the coating apparatus 1 shown in FIG. 1. The treatment liquid supply mechanism 8 includes a pump 81, a pipe 82, a treatment liquid replenishment unit 83, a pipe 84, an on-off valve 85, a pressure sensor 86, and a drive unit 87. The pump 81 is a supply source for supplying the treatment liquid to the nozzle 71 and supplies the treatment liquid by changing its volume. For example, a bellows-type pump as described in Japanese Patent Application Laid-Open No. 10-61558 can be used as the pump 81. As shown in FIG. 2, the pump 81 has a flexible tube 811 that is elastically expandable and contractible in the radial direction. One end of the flexible tube 811 is connected to the treatment liquid replenishment unit 83 via the pipe 82. The other end of the flexible tube 811 is connected to the nozzle 71 via the pipe 84.

[0037] The pump 81 has a bellows 812 that is elastically deformable in the axial direction. The bellows 812 has a small bellows section 813, a large bellows section 814, a pump chamber 815, and an operating disk section 816. The pump chamber 815 is disposed between the flexible tube 811 and the bellows 812. An incompressible medium is sealed in the pump chamber 815. The operating disk section 816 is connected to the drive section 87.

[0038] The processing liquid replenishment unit 83 has a storage tank 831 that stores the processing liquid. The storage tank 831 is connected to the pump 81 via a pipe 82. An on-off valve 833 is inserted in the pipe 82. The on-off valve 833 opens and closes in response to a command from the control unit 9. When the on-off valve 833 is opened, the processing liquid can be replenished from the storage tank 831 to the flexible tube 811 of the pump 81. When the on-off valve 833 is closed, the replenishment of the processing liquid from the storage tank 831 to the flexible tube 811 of the pump 81 is restricted.

[0039] The pipe 84 is connected to the output side of the pump 81. The on-off valve 85 is provided in the pipe 84. The on-off valve 85 opens and closes the pipe 84 in response to a command from the control unit 9. The on-off valve 85 opens and closes the pipe 84, switching between sending and stopping the processing liquid to the nozzle 71. The pressure sensor 86 is provided in the pipe 84. The pressure sensor 86 detects the pressure (discharge pressure) applied to the processing liquid sent to the nozzle 71, and outputs a signal indicating the detected pressure value to the control unit 9.

[0040] 1 and 2, a sensor 62 is disposed in the nozzle 71 to which the processing liquid is supplied from the processing liquid supply mechanism 8. The sensor 62 detects the height of the substrate S in the Z direction in a non-contact manner. The sensor 62 is electrically connected to the control unit 9. Based on the detection result of the sensor 62, the control unit 9 measures the distance (separation distance) between the floating substrate S and the upper surface of the coating stage 32. Then, based on the measured separation distance, the control unit 9 adjusts the coating position of the nozzle 71 using the positioning mechanism. Note that the sensor 62 can be, for example, an optical sensor or an ultrasonic sensor.

[0041] The substrate S carried out from the output conveyor 110 is dried in a drying device or the like to form a coating film. Then, as shown in Fig. 1, the substrate S on which the coating film has been formed is transported to a film thickness measuring instrument AP1 as needed, where the film thickness of the coating film is measured. As the film thickness measuring instrument AP1, for example, a spectroscopic ellipsometer, an X-ray reflectance measuring instrument, or the like can be used.

[0042] The coating mechanism 7 is equipped with a nozzle cleaning standby unit 72. The nozzle cleaning standby unit 72 performs predetermined maintenance on the nozzle 71 placed at the maintenance position. The nozzle cleaning standby unit 72 has a roller 721, a cleaning section 722, and a roller vat 723. The nozzle cleaning standby unit 72 cleans the nozzle 71 and forms a liquid pool, thereby preparing the discharge port of the nozzle 71 for a coating process.

[0043] FIG. 3 is a block diagram showing the configuration of the control unit 9. The control unit 9 controls the operation of each component in the coating apparatus 1. A computer can be used as the control unit 9. The control unit 9 includes a processor 91 and a memory 93. The processor has, for example, a CPU (Central Processing Unit). The memory 93 has a transient storage device such as a RAM (Random Access Memory). The memory 93 may also have a non-transient storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The memory 93 is connected to the processor 91 via a bus wiring.

[0044] The control unit 9 has a display device 95 that displays various information and an input device 97 that accepts user command inputs. The display device 95 and the input device 97 are connected to the processor 91 via a wiring bus. The display device 95 is, for example, a liquid crystal display. The input device 97 has, for example, a mouse or a keyboard. Note that the display device 95 may have a touch panel so that it functions as an input device.

[0045] The memory 93 stores a computer program 931. The computer program 931 is provided to the control unit 9 via a recording medium M. That is, the computer program 931 is recorded on the recording medium M so as to be readable by the control unit 9, which is a computer. The recording medium M is specifically a USB (Universal Serial Bus) memory, an optical disk such as a DVD (Digital Versatile Disc), a magnetic disk, or the like.

[0046] The processor 91 executes the computer program 931 to function as a discharge control unit 910, a film thickness distribution acquisition unit 911, an edge cut width setting unit 913, a feature amount calculation unit 915, a cost value calculation unit 917, and a parameter determination unit 919.

[0047] The discharge control unit 910 controls, based on preset control parameters, the operation (supply operation) of the pump 81 that supplies the processing liquid to the nozzle 71. In the coating apparatus 1, the control parameters are optimized so that the processing liquid discharged from the nozzle 71 is applied to the upper surface Sf of the substrate S with a uniform film thickness.

[0048] The control parameters are, for example, setting values ​​for pump control, and specifically, various parameters that define the movement of the operating disk unit 816 (for example, acceleration time, steady speed, time to maintain steady speed, deceleration time, etc.). The control parameters are optimized by the film thickness distribution acquisition unit 911, the edge cut width setting unit 913, the feature amount calculation unit 915, the cost value calculation unit 917, and the parameter determination unit 919. In other words, the film thickness distribution acquisition unit 911, the edge cut width setting unit 913, the feature amount calculation unit 915, the cost value calculation unit 917, and the parameter determination unit 919 constitute a parameter optimization device that optimizes the control parameters.

[0049] The film thickness distribution acquisition unit 911 acquires the film thickness distribution, which is the measurement result of the coating film formed on the substrate S, by controlling the coating apparatus 1 using the control parameters. The film thickness distribution of the coating film is measured by the film thickness measuring instrument AP1. The film thickness distribution acquisition unit 911 stores the acquired film thickness distribution in the memory 93.

[0050] FIG. 4 is a top view showing the upper surface Sf of the substrate S. As shown in FIG. 4, in this embodiment, when evaluating the film thickness of a coating film formed on the substrate S, the film thickness distribution on a reference line Ln set for the substrate S is acquired. The reference line Ln extends parallel to a direction that coincides with the transport direction (X direction) of the substrate S during the coating process of the coating apparatus 1. However, this is not essential, and for example, the reference line Ln may coincide with a diagonal line of the substrate S. Furthermore, although the reference line Ln passes through the center CP, this is also not essential. For example, the reference line Ln may be set at a position closer to one end of the substrate S.

[0051] The edge cut width setting unit 913 sets an edge cut width WE, which is the width of an edge cut region AE that extends inward from the edge (periphery) of the substrate S. As shown in FIG. 4, the edge cut region AE is annular (here, rectangular frame-shaped) that extends inward from the edge of the substrate S by the edge cut width WE. The region several millimeters inward from the edge of the substrate S includes areas where no coating film is formed and edge portions of the coating film, resulting in an uneven film thickness distribution and making it unsuitable for evaluating film thickness uniformity. Therefore, in order to perform edge cutting that excludes the film thickness distribution of the edge cut region AE from the overall film thickness distribution, the edge cut width WE, which is the width of the edge cut region AE, is set in advance. The edge cut width WE may be specified appropriately by the user or may be preset in the computer program 931.

[0052] The feature amount calculation unit 915 calculates feature amounts from the film thickness distribution acquired by the film thickness distribution acquisition unit 911. More specifically, the feature amount calculation unit 915 acquires the film thickness distribution in the target area AT excluding the edge cut area AE from the upper surface Sf of the substrate S (hereinafter also referred to as "target film thickness distribution"), and acquires the feature amounts.

[0053] Fig. 5 is a diagram showing an example of the film thickness distribution TD acquired by the film thickness distribution acquisition unit 911. In Fig. 5, the horizontal axis indicates the position on the substrate S (more specifically, the position on the reference line Ln). 5, the film thickness distribution can be divided into two parts: a coating start part PS and a coating end part PE. The coating start part PS corresponds to the part where the coating of the treatment liquid on the substrate S starts, and the coating end part PE corresponds to the part where the coating of the treatment liquid ends.

[0054] Typically, the film thickness distribution rises sharply from zero at the coating start point PS, then fluctuates upward and downward before converging to a nearly constant magnitude. At the coating end point PE, the film thickness distribution rises from a constant state, then falls sharply toward zero.

[0055] 5, the feature amount calculation unit 915 obtains the target film thickness distributions TTD1 and TTD2 by excluding data on the edge cut width WE (here, WE1 and WE2) set by the edge cut width setting unit 913 from the film thickness distribution TD. Then, the feature amount calculation unit 915 calculates the feature amount for each of the obtained target film thickness distributions TTD1 and TTD2.

[0056] The feature amount calculation unit 915 calculates feature amounts for each of the application start portion PS and the application end portion PE of the target film thickness distribution TTD. By optimizing the control parameters using the feature amount of the application start portion PS, the film thickness distribution of the application start portion PS can be made uniform. Furthermore, by evaluating the film thickness distribution of the application end portion PE and optimizing the control parameters, the film thickness distribution of the application end portion PE can be made uniform. The following mainly describes the calculation of the feature amount of the application start portion PS, but the feature amount of the application end portion PE can also be calculated using the same method.

[0057] When calculating a feature from the target film thickness distribution TTD, the feature calculation unit 915 calculates the amount of change from a film thickness representative value for the target film thickness distribution as the feature. The film thickness representative value is specifically a value calculated from the film thickness distribution in the target region AT, and is the median, average, or mode. In the following explanation, the film thickness representative value is the median (hereinafter referred to as the "median film thickness"). The median film thickness may be the median of the entire target film thickness distribution TTD, or the median of the remaining portion of the target film thickness distribution TTD excluding the upper and lower deviation portions. For example, the median film thickness may be the median of the inner portion excluding the portion several hundred mm inward from the edge of the substrate S.

[0058] In this embodiment, a threshold value TH1 (upper threshold value) that is a predetermined value greater than the median film thickness and a threshold value TH2 (lower threshold value) that is a predetermined value less than the median film thickness are set. Threshold values ​​TH1 and TH2 are threshold values ​​within an allowable range of variation from the median film thickness. It is preferable that the difference between the median film thickness and threshold value TH1 be the same as the difference between the median film thickness and threshold value TH2.

[0059] The feature amount calculation unit 915 acquires the amount of change from the median film thickness in the target film thickness distribution TTD as a feature amount. Specifically, the feature amount calculation unit 915 calculates the maximum value of the amount of change (difference) from the median film thickness in the target film thickness distribution TTD (hereinafter referred to as the "maximum amount of change QD").

[0060] Furthermore, the feature calculation unit 915 identifies peaks in the target film thickness distribution TTD at positions different from the position where the maximum change amount QD is obtained, in regions (excess regions) where the film thickness exceeds the thresholds TH1 and TH2, and obtains an excess amount QE, which is the difference between the peak value and the threshold. The feature calculation unit 915 also calculates the feature by adding the obtained excess amount QE to the maximum change amount QD. Note that if there are multiple locations where the thresholds TH1 and TH2 are exceeded, the excess amounts QE at each location are added together to calculate the feature.

[0061] 6 is a diagram conceptually showing an example of calculating the feature quantity F from the target film thickness distribution TTD. For example, the target film thickness distribution TTD shown in FIG. a In this case, the maximum change QD is taken in the upper fluctuation part that is larger than the median film thickness. a does not exceed the threshold value TH1 and the threshold value TH2. a In this case, only the maximum change QD is used as the feature.

[0062] In addition, the target film thickness distribution TTD b In this case, the maximum change QD is taken in the upward fluctuation part. b exceeds the threshold value TH1 at the position of the maximum change amount QD, but does not exceed the threshold value at other positions. b In this case, the target film thickness distribution TTD a Similarly, only the maximum change QD is taken as the feature.

[0063] Furthermore, the target film thickness distribution TTD c In this case, the maximum change QD is taken in the upward fluctuation part. c exceeds the threshold value TH1 at the position of the maximum change amount QD, and has an excess region RE that exceeds the threshold value TH2 in the downward deflection portion at other positions. c In this case, the value obtained by adding the excess amount QE, which is the difference between the peak value in the excess region RE and the threshold value TH2, to the maximum change amount QD is set as the feature amount.

[0064] <Cost value calculation> 3, a cost value calculation unit 917 calculates a cost value from the feature amount calculated by the feature amount calculation unit 915. Furthermore, a parameter determination unit 919 uses the cost value calculated by the cost value calculation unit 917 to determine a control parameter to be evaluated next.

[0065] As described above, in this embodiment, the feature amount calculation unit 915 calculates the feature amount F for each of the plurality of edge cut widths WE set by the edge cut width setting unit 913. Therefore, the cost value calculation unit 917 integrates the feature amounts F calculated for each edge cut width WE to calculate a cost value. In the following description, the plurality of edge cut widths are referred to as WE k (k is a positive integer). Also, the edge cut width WE k The feature value F of k " may be written as ".

[0066] FIG. 7 is a diagram showing the relationship between the edge cut width WE and the feature amount F. In FIG. 7, the horizontal axis represents the edge cut width WE, and the vertical axis represents the feature amount F. As shown in FIG. 7, the larger the value of the edge cut width WE (edge ​​cut), the smaller the value of the feature amount F, since the edge of the substrate S, which has large variations in film thickness, is ignored. Conversely, the smaller the value of the edge cut width WE, the larger the value of the feature amount F. In other words, the edge cut width WE and the feature amount F show an inverse correlation curve C, as shown in FIG. 7. Therefore, in this embodiment, the feature amount F k The area S below the curve C is calculated as the integrated value of

[0067] In calculating this area S, both the edge cut width WE on the horizontal axis and the feature quantity F on the vertical axis are normalized to match the scale. Normalization is performed to reflect the importance of each axis, bringing them within the range of 0 to 1, so that the final area value also takes a value between 0 and 1. This normalization makes it possible to appropriately compare and evaluate the differences between data on different film thickness distributions.

[0068] The cost value calculation unit 917 first normalizes each feature amount Fk so that the value falls within the range of 0 to 1 using the following equation (1).

[0069]

number

[0070] In the above formula (1), the tanh function is used, but the feature value F is a value greater than or equal to 0, so the normalized feature value F k can take a value between 0 and 1. The cost value calculation unit 917 normalizes the feature amount Fk, and then calculates the area S based on equation (2).

[0071]

number

[0072] According to equation (2), the normalized feature F k The weight W k The weighted sum weighted by (coefficient) is calculated as the area S. k are set in advance so that the sum of these is 1. In other words, the area S calculated by equation (2) is the weighted average of the feature amount Fk.

[0073] When evaluating the film thickness uniformity, the importance of the film thickness varies depending on the position on the substrate S. That is, the feature value F k The importance of the edge cut width WE k Therefore, the edge cut width WE k By setting the weight for each edge, the edge cut width WE k The importance of each item can be reflected in the evaluation.

[0074] Next, the cost value calculation unit 917 calculates a cost value from the obtained area S based on the cost function expressed by equation (3).

[0075]

number

[0076] By adopting the cost function of the above formula (3), the final cost value falls within the range of 0 to 10. Formula (3) assumes a minimization problem as automatic optimization adjustment, and the better the film thickness state, the closer the cost value approaches 0. The parameter determination unit 919 determines the control parameters to be evaluated next by an optimization method using the cost value calculated based on formula (3). As the optimization method, for example, Bayesian optimization can be used.

[0077] As described above, the control unit 9, which functions as a parameter optimization device according to this embodiment, optimizes control parameters used in a coating process for coating a substrate S with a processing liquid. The parameter optimization device includes a film thickness distribution acquisition unit 911, an edge cut width setting unit 913, a feature value calculation unit 915, a cost value calculation unit 917, and a parameter determination unit 919. The film thickness distribution acquisition unit 911 acquires the film thickness distribution of a coating film formed on the substrate S. The edge cut width setting unit 913 sets an edge cut width WE, which is the width dimension of an edge cut region AE extending inward from an edge of the substrate S. The feature value calculation unit 915 calculates a feature value F of the film thickness distribution using the amount of change from a film thickness representative value for a target film thickness distribution TTD in a target region AT, which is the upper surface Sf of the substrate S excluding the edge cut region AE. The cost value calculation unit 917 calculates a cost value using the feature value F. The parameter determination unit 919 determines the control parameters based on the cost value. This configuration allows the uniformity of the film thickness distribution to be appropriately quantified by calculating a feature value indicating the amount of change from a film thickness representative value. This allows the control parameters used in the coating process to be appropriately optimized based on the film thickness distribution.

[0078] Furthermore, a threshold value TH1, which is an upper threshold value greater than the representative film thickness value, and a threshold value TH2, which is a lower threshold value smaller than the representative film thickness value, are set in advance. The feature value calculation unit 915 calculates a feature value F using the change amount QD and an excess amount QE when the target film thickness distribution TTD exceeds the threshold value TH1 or TH2. With this configuration, by adding the excess amount QE when the threshold values ​​TH1 and TH2 are exceeded to the feature value F, the degree of abnormality in the film thickness distribution can be reflected in the feature value F.

[0079] Furthermore, the edge cut width setting unit 913 can set a plurality of edge cut widths WE that are different from one another. The feature amount calculation unit 915 calculates a feature amount F from the target film thickness distribution TTD for each target area AT, excluding edge cut areas AE of the substrate S with each of the plurality of edge cut widths WE. The cost value calculation unit 917 calculates a cost value using the feature amount F for each target area AT. With this configuration, the feature amounts calculated for the different edge cut widths WE can be integrated to calculate a cost value.

[0080] The cost value calculation unit 917 calculates a cost value using a weighted sum obtained by weighting and adding the feature amount F for each edge cut width WE. With this configuration, it is possible to calculate a cost value that reflects the importance of each edge cut width.

[0081] The control unit 9 executes an optimization method for optimizing parameters used in a coating process for coating a processing liquid on the substrate S. The parameter optimization method includes the steps of: a) acquiring a film thickness distribution of a coating film formed on the substrate S; b) setting an edge cut width WE, which is the width dimension of an edge cut region AE that extends inward from an edge of the substrate S; c) calculating a feature value F indicating the amount of change from a representative film thickness value for a target film thickness distribution TTD in a target region AT excluding the edge cut region AE on the upper surface Sf, which is the surface of the substrate S; d) calculating a cost value using the feature value F; and f) determining parameters based on the cost value.

[0082] The computer program 931 can be executed by the control unit 9, which is a computer. The computer program 931 causes the control unit 9 to execute the parameter optimization method.

[0083] <2. Modifications> Although the embodiments have been described above, the present invention is not limited to the above and various modifications are possible.

[0084] For example, in the above embodiment, the film thickness distribution is divided into a coating start portion PS and a coating end portion PE, and the feature amount is calculated for each portion. However, the feature amount may be calculated from the entire film thickness distribution without dividing it into the coating start portion PS and the coating end portion PE.

[0085] In the above embodiment, the parameter optimization device is realized by the control unit 9 provided in the coating device 1. However, the parameter optimization device may be configured as a device different from the coating device 1.

[0086] Although the present invention has been described in detail, the above description is merely illustrative in all respects and does not limit the present invention. It is understood that countless variations not illustrated can be envisioned without departing from the scope of the present invention. The configurations described in the above embodiments and variations can be combined or omitted as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0087] 9: Control unit (parameter optimization device) 911: Film thickness distribution acquisition unit 913: Edge cut width setting section 915: Feature calculation unit 917: Cost value calculation unit 919: Parameter determination unit 931: Computer Program AE: Edge cut area AT: Target area S: Substrate Sf: Top surface (surface of substrate)

Claims

1. A parameter optimization apparatus for optimizing parameters used in a coating process for coating a substrate with a processing liquid, comprising: a film thickness distribution acquisition unit that acquires a film thickness distribution of a coating film formed on a substrate; an edge cut width setting unit that sets an edge cut width, which is a width dimension of an edge cut region that spreads inward from an edge of the substrate; a feature value calculation unit that calculates a feature value indicating a change amount from a representative film thickness value for the film thickness distribution in a target region excluding the edge cut region on the surface of the substrate; a cost value calculation unit that calculates a cost value using the feature amount; a parameter determination unit that determines the parameters based on the cost values; A parameter optimization device comprising:

2. 2. The parameter optimization device according to claim 1, an upper threshold value that is greater than the representative film thickness value and a lower threshold value that is smaller than the representative film thickness value are set in advance; The feature amount calculation unit calculates the feature amount using the amount of change and an excess amount when the film thickness distribution exceeds the upper threshold or the lower threshold.

3. 3. The parameter optimization device according to claim 1 or 2, the edge cut width setting unit is capable of setting a plurality of different edge cut widths, the feature amount calculation unit calculates the feature amount from the film thickness distribution for each target region of the substrate excluding each of the regions of the plurality of edge cut widths; The cost value calculation unit calculates the cost value using the feature amount for each of the target regions.

4. 4. The parameter optimization device according to claim 3, The cost value calculation unit calculates the cost value using a weighted sum obtained by weighting and adding the feature amounts for each edge cut width.

5. A parameter optimization method for optimizing parameters used in a coating process for coating a substrate with a processing liquid, comprising: a) obtaining a film thickness distribution of a coating film formed on a substrate; b) setting an edge cut width, which is a width dimension of an edge cut region extending inward from an edge of the substrate; c) calculating a feature value indicating a variation from a representative film thickness value for the film thickness distribution in a target region excluding the edge cut region on the surface of the substrate; d) calculating a cost value using the feature amount; e) determining said parameters based on said cost values; A parameter optimization method comprising:

6. A computer-executable computer program, A computer program that causes a computer to execute the parameter optimization method according to claim 5.

Images