Parameter optimization device, parameter optimization method, and computer program

Abstract

To provide a technology capable of efficiently optimizing a control parameter.SOLUTION: A parameter determination part 913 uses a plurality of pieces of acquired film thickness information to determine the next control parameter to be evaluated. A film thickness information acquisition part 914 acquires film thickness information TH1 based on a measurement result of film thickness of a coating film formed by controlling a coating device by using a control parameter P1 determined by the parameter determination part 913. A film thickness information estimation part 915 estimates film thickness information corresponding to a control parameter P2 determined by the parameter determination part 913 by using an estimation model Y for outputting film thickness information with the control parameter and process information as inputs. A loop control part 918 performs control so as to alternately execute first processing including processing of the parameter determination part 913 and processing of the film thickness information acquisition part 914, and second processing including the processing of the parameter determination part 913 and processing of the film thickness information estimation part 915.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The subject matter disclosed in this specification relates to a parameter optimization device, a parameter optimization method, and a computer program. [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 discharges a processing liquid from a slit nozzle by driving a pump, thereby coating the processing liquid over the entire substrate being transported. With the recent trend toward higher product quality, such coaters are required to apply the processing liquid so that the film thickness of the processing liquid is uniform over the entire substrate. For example, in Patent Document 1, parameters for controlling the pump are adjusted and optimized by repeatedly measuring the discharge characteristics when discharging the processing liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-040046 [Patent Document 2] International Publication No. 2019 / 244474 [Non-patent literature]

[0004] [Non-Patent Document 1] K. Swersky et al., "Multi-Task Bayesian Optimization," [online], [Retrieved June 1, 2018], NIPS, 2013, Internet<https: / / papers.nips.cc / paper / 5086-multi-task-bayesian-optimization.pdf> Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of Patent Document 1, the control process and measurement of the ejection characteristics are repeated multiple times, which may result in a long time required to optimize the control parameters.

[0006] An object of the present invention is to provide a technique that can efficiently optimize control parameters. [Means for solving the problem]

[0007] In order to solve the above problem, a first aspect of the present invention is a parameter optimization device that optimizes control parameters for controlling a coating device that discharges a processing liquid onto a substrate to form a coating film, and includes: a parameter determination unit that determines a control parameter to be evaluated next using multiple pieces of film thickness information, each of which is associated with a specific control parameter; a film thickness information acquisition unit that acquires film thickness information based on measurement results of the film thickness of a coating film formed by controlling the coating device using the control parameters determined by the parameter determination unit; a film thickness information estimation unit that estimates film thickness information corresponding to the control parameter determined by the parameter determination unit using an estimation model that receives control parameters and process information as input and outputs film thickness information; and a loop control unit that controls the parameter determination unit, the film thickness information acquisition unit, and the film thickness information estimation unit so that a first process including a process by the parameter determination unit and a process by the film thickness information acquisition unit and a second process including a process by the parameter determination unit and a process by the film thickness information acquisition unit are alternately executed.

[0008] A second aspect is the parameter optimization device of the first aspect, further comprising a learning unit that learns the estimation model using the film thickness information acquired by the film thickness information acquisition unit.

[0009] A third aspect is a parameter optimization device according to the first or second aspect, wherein the second process is a process of repeating the process of the parameter determination unit and the process of the film thickness information estimation unit multiple times, and the loop control unit executes the first process when the number of times film thickness information is estimated by the film thickness information estimation unit in the second process reaches a predetermined number.

[0010] A fourth aspect is the parameter optimization device of the first or second aspect, wherein the parameter determination unit calculates an evaluation value from the film thickness information, and determines a control parameter to be evaluated next based on the evaluation value.

[0011] A fifth aspect is the parameter optimization device according to the fourth aspect, wherein the parameter determination unit determines the control parameter to be evaluated next using a multitask Bayesian optimization algorithm.

[0012] A sixth aspect is a parameter optimization method for optimizing parameters for controlling a coating apparatus that discharges a processing liquid onto a substrate to form a coating film, the method including: a) a parameter determination step of determining a control parameter to be evaluated next using a plurality of pieces of film thickness information, each of which is associated with a specific parameter; b) a film thickness information acquisition step of acquiring film thickness information based on measurement results of a coating film formed by controlling the coating apparatus using the control parameters determined by the parameter determination step; and c) a film thickness information estimation step of estimating film thickness information corresponding to the control parameters determined by the parameter determination step using an estimation model that receives control parameters and process information as input and outputs film thickness information, and the first process including the parameter determination step and the film thickness information acquisition step and the second process including the parameter determination step and the film thickness information estimation step are alternately performed.

[0013] A seventh aspect is a computer program executable by a computer, causing the computer to execute the parameter optimization method of the sixth aspect. [Effects of the Invention]

[0014] According to the first to seventh aspects, a search for control parameters via an estimation model and a search for control parameters based on time-consuming film thickness measurement results are alternately performed, thereby reducing the number of film thickness measurements and efficiently optimizing the control parameters. Furthermore, by including process information in the input of the estimation model, film thickness information obtained in a different process can be used as training data. Therefore, inputting process information can improve the output accuracy of the estimation model. Therefore, the control parameters can be optimized with high accuracy.

[0015] According to the parameter optimization device of the second aspect, the accuracy of the estimation model can be improved by performing learning using the film thickness information of the coating film measured during optimization.

[0016] According to the parameter optimization device of the third aspect, the parameter optimization time can be further reduced.

[0017] According to the parameter optimization device of the fifth aspect, even if there is a difference between the distribution of evaluation values ​​of film thickness information based on measurement results and the distribution of evaluation values ​​of film thickness information via an estimation model, it is possible to perform Bayesian optimization search more efficiently. [Brief explanation of the drawings]

[0018] [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 diagram showing the configuration of a control unit together with the flow of data. [Figure 5] FIG. 10 is a diagram illustrating an example of a flow of a control parameter optimization process performed by a control unit. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] <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 functions as a parameter optimization apparatus that optimizes parameters for controlling the discharge of the processing liquid.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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).

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The processor 91 executes the computer program 931 to function as a discharge control unit 910 , a parameter determination unit 913 , a film thickness information acquisition unit 914 , a film thickness information estimation unit 915 , a learning unit 916 and a loop control unit 918 .

[0048] 4 is a diagram showing the configuration of the control unit 9 together with the data flow. The discharge control unit 910 controls the operation (supply operation) of the pump 81 that supplies the processing liquid to the nozzle 71 based on preset control parameters. In the coating apparatus 1, in order to coat the processing liquid discharged from the nozzle 71 onto the upper surface Sf of the substrate S with a uniform film thickness, before starting production (or mass production) of the substrate S, control parameters closely related to the discharge pressure waveform are optimized in advance so that the discharge pressure waveform has an ideal shape.

[0049] The control parameters are set values ​​for pump control, such as various parameters that define the movement of the actuation disk unit 816 (e.g., acceleration time, steady speed, time to maintain steady speed, deceleration time, etc.). The control parameters are optimized by the parameter determination unit 913, film thickness information acquisition unit 914, film thickness information estimation unit 915, learning unit 916, and loop control unit 918. In other words, the parameter determination unit 913, film thickness information acquisition unit 914, film thickness information estimation unit 915, learning unit 916, and loop control unit 918 constitute a parameter optimization device that optimizes the control parameters.

[0050] The parameter determination unit 913 determines the next control parameter to be evaluated using a plurality of pieces of acquired film thickness information, each of which is associated with a specific control parameter. As shown in FIG. 4, the acquired film thickness information used by the parameter determination unit 913 is stored in a database DB1 in association with a specific control parameter. The database DB1 is a function realized by the memory 93. The film thickness information is information about the film thickness of the coating film formed on the substrate S, and is the film thickness distribution (film thickness profile) in one direction. Note that the film thickness information is not limited to the film thickness distribution. For example, an index representing the uniformity of the film thickness (such as the average value and variance) can also be used as the film thickness information.

[0051] The film thickness information acquisition unit 914 acquires film thickness information TH1, which is a measurement result of the coated film formed on the substrate S, by controlling the coating apparatus 1 using the control parameter P1 determined by the parameter determination unit 913. Specifically, the discharge control unit 910 performs a discharge process based on the control parameter P1 to form a coated film on the substrate S, and then the film thickness of the formed coated film is measured by the film thickness measuring device AP1. The film thickness information acquisition unit 914 acquires the film thickness information TH1 using the measured film thickness. The film thickness information acquisition unit 914 stores the acquired film thickness information TH1 in the database DB1 in association with the control parameter P1 (i.e., the corresponding control parameter P1), which is the control condition when the film thickness information TH1 was obtained.

[0052] The film thickness information estimation unit 915 uses an estimation model Y to estimate film thickness information TH2 corresponding to the control parameter P2 determined by the parameter determination unit 913. The estimation model Y is a trained model that receives control parameters and process information as inputs and outputs film thickness information. The process information is information related to the process conditions for forming the coating film and is different from the control parameters. Examples of the process information that can be used include the model name of the coating apparatus, the size and type of substrate (surface material, etc.) on which the coating film is formed, and information about the processing liquid (physical property information, etc.). The process information used as input may be one type of information or multiple types of information. The film thickness information estimation unit 915 stores the estimated film thickness information TH2 in database DB1 in association with the corresponding control parameter P2.

[0053] A parameter determination unit 913 determines the next control parameter to be evaluated using film thickness information TH1 stored in database DB1 by a film thickness information acquisition unit 914 or TH2 stored in database DB1 by a film thickness information estimation unit 915.

[0054] The learning unit 916 learns an estimation model Y by machine learning using training data in which the acquired control parameters and process information are input and film thickness information is output. For example, by using an RNN (Recurrent Neural Network) as the estimation model Y, it becomes possible to estimate the film thickness distribution, which is one-dimensional data, as film thickness information. Furthermore, when the film thickness information is used as an index showing uniformity, for example, random forest regression can be used as the estimation model Y.

[0055] As shown in FIG. 4, training data (learning data set) used by the learning unit 916 for machine learning is stored in a database DB2. The database DB2 is a function realized by the memory 93. In the database DB2, film thickness information is stored in association with the corresponding control parameters and corresponding process information. The film thickness information acquisition unit 914 stores the acquired film thickness information TH1 in the database DB2 in association with the corresponding control parameters and process information. Also, as shown in FIG. 4, the database DB2 also stores film thickness information provided from a database DB3 separate from the coating apparatus 1 via a network (not shown) or the like.

[0056] The loop control unit 918 controls the parameter determination unit 913, the film thickness information acquisition unit 914, and the film thickness information estimation unit 915 so that the first process and the second process are executed alternately. Here, the first process is a process including a process of determining control parameters by the parameter determination unit 913 and a process of acquiring film thickness information by the film thickness information acquisition unit 914. The second process is a process including a process of determining control parameters by the parameter determination unit 913 and a process of estimating film thickness information by the film thickness information estimation unit 915. As will be described later, the loop control unit 918 controls the second process so that the process by the parameter determination unit 913 and the process by the film thickness information estimation unit 915 are repeated multiple times. This will be described in detail with reference to FIG. 5.

[0057] <Parameter optimization process> Fig. 5 is a diagram showing an example of the flow of parameter optimization processing by the control unit 9. In the flow of Fig. 5, the parameter determination step S10 corresponds to the control parameter determination processing by the parameter determination unit 913. Furthermore, the estimation step S3 corresponds to the film thickness information estimation processing by the film thickness information estimation unit 915, and the acquisition step S5 corresponds to the film thickness information estimation processing by the film thickness information acquisition unit 914. In other words, the first processing corresponds to the parameter determination step S10 and the acquisition step S5, and the second processing corresponds to the parameter determination step S10 and the estimation step S3.

[0058] In addition, in the flow of FIG. 5, the estimated upper limit number N est is set. Estimated upper limit N est is the number of times the estimation step S3 should be repeated in one second process. In addition, the loop control unit 918 counts the number of times the estimation step S3 has been executed, and therefore, the loop control unit 918 counts the number of times the estimation step S3 has been executed. est Use as a variable.

[0059] In the flow of FIG. 5, the upper limit number of searches N all is set. Search limit N all is the number of times that the control parameters should be searched in one optimization process (i.e., the number of times that the parameter determination unit 913 determines the control parameters). The loop control unit 918 counts the number of times that the search is executed, and therefore, ser Use as a variable.

[0060] When the optimization process starts, first, the parameter determination unit 913 determines initial control parameters (initial parameter determination step S1). The initial control parameters may be values ​​that have already been used in the coating apparatus. Alternatively, the initial control parameters may be values ​​that are randomly determined.

[0061] Next, the loop control unit 918 calculates the estimated number of executions C est is the estimated upper limit N est In the determination step S2, it is determined whether the estimated number of executions C est is the estimated upper limit N est If it is determined that the number of times of execution of estimation C has not been reached, the loop control unit 918 causes the film thickness information estimation unit 915 to execute estimation processing. That is, the film thickness information estimation unit 915 inputs the control parameters determined in the initial parameter determination step S1 (or the parameter determination step S10 described later) into the estimation model Y, thereby estimating film thickness information (estimation step S3). In addition, the loop control unit 918 causes the number of times of execution of estimation C est (increment step S4). When the increment step S4 is completed, the control unit 9 proceeds to the evaluation value calculation step S9.

[0062] In the determination step S2, the estimated number of executions C est is the estimated upper limit N est If it is determined that the number of executions has reached the predetermined number, the film thickness information acquisition unit 914 executes an acquisition process (acquisition step S5). Specifically, the discharge control unit 910 controls the pump 81 using the control parameter P1 determined in the initial parameter determination step S1 (or the parameter determination step S10 described later), thereby forming a coating film on the substrate S. Then, the film thickness of the coating film is measured by the film thickness measuring device AP1. The film thickness information acquisition unit 914 acquires film thickness information, which is the measurement result of the film thickness. After the acquisition step S5, the loop control unit 918 executes the acquisition process for the estimated number of executions C est is set to 0 (reset step S6).

[0063] After the reset step S6, the loop control unit 918 determines whether or not to update the estimation model Y (determination step S7). The estimation model Y may be updated, for example, when the number of pieces of film thickness information TH1 acquired in the acquisition step S5 that have not been used for re-learning the estimation model Y reaches a predetermined number or more. If it is determined in the determination step S7 that the estimation model Y should be updated, the loop control unit 918 causes the learning unit 916 to update the estimation model Y (model update step S8). That is, the estimation model Y is re-learned using the film thickness information added to the database DB1 in the acquisition step S5. After the model update step S8 is completed, the control unit 9 proceeds to the evaluation value calculation step S9. On the other hand, if it is determined in the determination step S7 that the estimation model Y should not be updated, the control unit 9 skips the model update step S8 and proceeds to the evaluation value calculation step S9.

[0064] In an evaluation value calculation step S9, the parameter determination unit 913 calculates an evaluation value for the film thickness information TH2 estimated in the estimation step S3 or the film thickness information TH1 obtained in the acquisition step S5. For example, an index representing the magnitude of variation in film thickness distribution may be used as an evaluation value for achieving a uniform film thickness. In this case, the error from a predetermined target film thickness or the variation in the error may be used as the evaluation value.

[0065] Next, the parameter determination unit 913 determines the control parameters to be evaluated next based on the evaluation value obtained in the evaluation value calculation step S9 (parameter determination step S10). Specifically, techniques such as reinforcement learning (RL), Bayesian optimization, or particle swarm optimization can be used. These techniques enable the control parameters to be updated for each trial so that the evaluation value is optimized.

[0066] Alternatively, the parameter search method may be the multitask Bayesian optimization described in Non-Patent Document 1 or Patent Document 2 (WO 2019 / 244474). The film thickness information TH1 acquired in the acquisition step S5 may be affected by noise components generated by actual measurements. Therefore, there is a possibility that a difference in the distribution of evaluation values ​​may occur between the film thickness information TH2 estimated in the estimation step S3 and the film thickness information TH1 acquired in the acquisition step S5. Therefore, by using multitask Bayesian optimization with one set as target observation data and the other set as reference observation data, it becomes possible to perform Bayesian optimization search more efficiently even if there is a difference in the distribution of evaluation values ​​between the two sets.

[0067] After the parameter determination step S10, the loop control unit 918 determines the number of search executions C ser Then, the loop control unit 918 increments the search execution count C by 1 (increment step S11). ser is the search limit N all In the determination step S12, it is determined whether the search execution count C ser is the search limit N all If it is determined that the number of search executions C has not been reached, the control unit 9 returns to the determination step S2 again and continues the process. ser is the search limit N all If it is determined that the optimum control parameters have been reached, the control unit 9 ends the process. The optimized control parameters are stored in the memory 93 and are used in subsequent coating processes in the coating apparatus 1.

[0068] As described above, according to the control unit 9 of this embodiment, the search for control parameters via the estimation model Y and the search for control parameters based on film thickness measurement, which takes time, are alternately performed. This reduces the number of times a coating film is formed and the film thickness is measured, thereby shortening the time required to adjust the control parameters. Furthermore, since the number of times a coating film is formed can be reduced, the consumption of the substrate S and the processing liquid can be reduced, thereby reducing the environmental impact. Furthermore, by including process information in the input of the estimation model, film thickness information obtained in different processes can be used as training data. Therefore, inputting process information can improve the output accuracy of the estimation model. Therefore, the search for control parameters can be performed accurately, thereby enabling efficient optimization.

[0069] Furthermore, by re-learning the estimation model Y using film thickness information measured during optimization of the control parameters, the output accuracy of the estimation model Y can be improved along with optimization.

[0070] In the second process, the parameter determination unit determines the next control parameter and the film thickness information estimation unit estimates the film thickness information TH2. est This is performed multiple times until the parameter is optimized. This can further reduce the time required for parameter optimization.

[0071] <2. Variations> Although the embodiments have been described above, the present invention is not limited to the above and various modifications are possible.

[0072] For example, in the flow shown in FIG. 5, the parameter determination step S10 and the estimation step S3 are performed for the second process until the upper limit number of estimations N estIn the first process, the parameter determination step S10 and the acquisition step S5 are executed only once, whereas in the second process, the parameter determination step S10 and the acquisition step S5 are executed only once. However, in the first process, the loop control unit 918 may also perform control so that the parameter determination step S10 and the acquisition step S5 are executed twice or more times.

[0073] Furthermore, the film thickness information obtained in the estimation step S3 and the acquisition step S5 may be the same as the evaluation value obtained in the evaluation value calculation step S9. In this case, the estimation model Y may be trained so that the estimation model Y outputs the evaluation value from the control parameters. Furthermore, the film thickness information acquisition unit 914 may calculate the evaluation value from the film thickness distribution.

[0074] In the flow shown in FIG. 5, in the determination step S12, the search execution count C ser is the search limit N all Alternatively, the loop control unit 918 may perform control such that the generation of the control parameters is repeated until the evaluation value calculated in the evaluation value calculation step S9 exceeds a predetermined reference value.

[0075] Furthermore, in the above embodiment, the parameter optimization device is realized by the control unit 9 provided in the coating device 1, but it may be configured as a device different from the coating device 1.

[0076] 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]

[0077] 1: Coating device 9: Control unit (parameter optimization device) 913: Parameter determination unit 914: Film thickness information acquisition unit 915: Film Thickness Information Estimation Unit 916: Learning Department 918: Loop control section 931: Computer Program Y: Estimated model

Claims

1. A parameter optimization device for optimizing control parameters for controlling a coating device that discharges a treatment liquid onto a substrate to form a coating film, the parameter optimization device comprising: a parameter determination unit that determines a control parameter to be next evaluated using a plurality of pieces of film thickness information, each of which is associated with a specific control parameter; a film thickness information acquiring unit that acquires film thickness information based on a measurement result of a film thickness of a coating film formed by controlling a coating device using the control parameters determined by the parameter determining unit; a film thickness information estimation unit that estimates film thickness information corresponding to the control parameters determined by the parameter determination unit using an estimation model that receives control parameters and process information as inputs and outputs film thickness information; a loop control unit that controls the parameter determination unit, the film thickness information acquisition unit, and the film thickness information estimation unit so that a first process including a process by the parameter determination unit and a process by the film thickness information acquisition unit, and a second process including a process by the parameter determination unit and a process by the film thickness information estimation unit are alternately executed; A parameter optimization device comprising:

2. 2. The parameter optimization device according to claim 1, a learning unit that learns the estimation model using the film thickness information acquired by the film thickness information acquisition unit; The parameter optimization device further comprises:

3. 3. The parameter optimization device according to claim 1 or 2, the second process is a process of repeating the process of the parameter determination unit and the process of the film thickness information estimation unit a plurality of times; The parameter optimization device, wherein the loop control unit executes the first process when the number of times that the film thickness information has been estimated by the film thickness information estimation unit reaches a predetermined number in the second process.

4. 3. The parameter optimization device according to claim 1 or 2, The parameter determination unit calculates an evaluation value from the film thickness information, and determines a control parameter to be evaluated next based on the evaluation value.

5. 5. The parameter optimization device according to claim 4, The parameter determination unit determines the control parameter to be next evaluated using a multitask Bayesian optimization algorithm.

6. A parameter optimization method for optimizing parameters for controlling a coating apparatus that discharges a treatment liquid onto a substrate to form a coating film, comprising: a) a parameter determination step of determining a control parameter to be next evaluated using a plurality of pieces of film thickness information, each of which is associated with a specific parameter; b) a film thickness information acquisition step of acquiring film thickness information based on measurement results of a coating film formed by controlling a coating device using the control parameters determined in the parameter determination step; c) a film thickness information estimation step of estimating film thickness information corresponding to the control parameters determined in the parameter determination step using an estimation model that receives control parameters and process information as inputs and outputs film thickness information; wherein a first process including the parameter determination step and the film thickness information acquisition step and a second process including the parameter determination step and the film thickness information estimation step are alternately performed.

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

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