Substrate processing method and information processing apparatus

Abstract

In this substrate processing apparatus (300), a processing liquid that contains a sublimable substance and a solvent is supplied to a main surface of a substrate (W) on which a pattern is formed, thereby forming a liquid film of the processing liquid. A solidified film that contains the sublimable substance is formed on the main surface by evaporating the solvent from the thus-formed liquid film. The solidified film is removed from the main surface by sublimating the solidified film. Here, in the information processing apparatus (300), the change with time of the concentration of the sublimable substance is acquired by a concentration acquisition unit (15) on the basis of the absorbance of the liquid film that is formed on the main surface during the time period in which the solvent is evaporated. The collapse rate of the pattern when the solidified film is sublimated is predicted by a prediction unit (16) on the basis of the acquired change with time of the concentration. When the predicted collapse rate is equal to or greater than a specific threshold value, the prediction result is output by an output unit (17) before the solidified film is sublimated.

Description

Substrate processing method and information processing apparatus

[0001] The present invention relates to a substrate processing method for processing a substrate and an information processing apparatus.

[0002] In recent years, the miniaturization of patterns formed on substrates has tended to weaken the pattern strength. In this case, when a liquid applied to a substrate is dried, the pattern is prone to collapse due to the surface tension acting between the liquid and the surface of the pattern formed on the substrate. Sublimation drying is known as a method for drying a substrate while suppressing pattern collapse. Sublimation drying is a technique for drying a liquid applied to the surface of a substrate by converting it into a solid and then changing the phase from solid to gas.

[0003] In the substrate processing method described in Patent Document 1, a pre-drying treatment liquid containing a sublimable substance and a solvent is supplied to a surface of a substrate on which a pattern has been formed. Next, the solvent is evaporated from the pre-drying treatment liquid on the surface of the substrate, thereby forming a solidified substance containing the sublimable substance on the surface of the substrate. Here, the ratio of the thickness of the solidified substance to the height of the pattern is limited to a predetermined range. Thereafter, the solidified substance is removed from the surface of the substrate by sublimating it.

[0004] Japanese Patent Application Laid-Open No. 2020-4948

[0005] Patent Document 1 describes that the above-described sublimation drying reduces pattern collapse that occurs when the substrate is dried even when the pattern strength is extremely low. It is desired to further reduce pattern collapse in sublimation drying.

[0006] An object of the present invention is to provide a substrate processing method and information processing apparatus that can reduce pattern collapse during sublimation drying.

[0007] A substrate processing method according to one aspect of the present invention is a substrate processing method executed by a computer, in which a processing liquid containing a sublimable substance and a solvent is supplied to a main surface of a substrate on which a pattern has been formed, to form a liquid film of the processing liquid, the solvent is evaporated from the formed liquid film to form a solidified film containing the sublimable substance on the main surface, and the solidified film is removed from the main surface by sublimating it, the method including: acquiring a change over time in concentration of the sublimable substance based on an absorbance of the liquid film formed on the main surface during a period in which the solvent is evaporated; predicting a collapse rate of the pattern when the solidified film is sublimated based on the acquired change over time in concentration; and, if the predicted collapse rate is equal to or greater than a predetermined threshold, outputting a process using the prediction result before sublimating the solidified film.

[0008] According to another aspect of the present invention, an information processing apparatus is used for substrate processing, which comprises supplying a processing liquid containing a sublimable substance and a solvent onto a main surface of a substrate on which a pattern has been formed, thereby forming a liquid film of the processing liquid, evaporating the solvent from the formed liquid film to form a solidified film containing the sublimable substance on the main surface, and removing the solidified film from the main surface by sublimating the solidified film, and includes: an acquisition unit that acquires a change in concentration of the sublimable substance over time based on the absorbance of the liquid film formed on the main surface during a period in which the solvent is evaporated; a prediction unit that predicts a collapse rate of the pattern when the solidified film is sublimated, based on the change in concentration over time acquired by the acquisition unit; and an output unit that outputs a process using the prediction result before sublimating the solidified film if the collapse rate predicted by the prediction unit is equal to or greater than a predetermined threshold value.

[0009] An object of the present invention is to reduce pattern collapse during sublimation drying.

[0010] FIG. 1 is a diagram showing an example of the configuration of a substrate processing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the configuration of a processing unit. FIG. 3 is a block diagram showing the functional configuration of an information processing apparatus. FIG. 4 is a block diagram showing the functional configuration of a processing unit. FIG. 5 is a flowchart showing an example of the flow of sublimation drying processing by the processing unit. FIG. 6 is a flowchart showing an example of the flow of prediction processing by the information processing apparatus. FIG. 7 is a diagram showing an example of a measurement unit in a second modified example.

[0011] 1. Substrate Processing Apparatus A substrate processing method and information processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In the following description, the term "substrate" refers to a semiconductor substrate (wafer), a substrate for an FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (Electro Luminescence) display device, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, or a substrate for a solar cell. One surface of the substrate is called the main surface, and the surface opposite the main surface is called the back surface. A predetermined pattern is formed on the main surface of the substrate.

[0012] FIG. 1 is a diagram showing an example of the configuration of a substrate processing apparatus including an information processing apparatus according to an embodiment of the present invention. As shown in FIG. 1, a substrate processing apparatus 300 includes an information processing apparatus 100 and a processing unit 200. FIG. 1 mainly shows the hardware configuration of the information processing apparatus 100. Specifically, the information processing apparatus 100 includes a control unit 110, a RAM (random access memory) 120, a ROM (read only memory) 130, a storage unit 140, an operation unit 150, a display unit 160, an input / output I / F (interface) 170, and a bus 180. The information processing apparatus 100 may be configured, for example, by a computer.

[0013] The control unit 110, RAM 120, ROM 130, storage unit 140, operation unit 150, display unit 160, and input / output I / F 170 are connected to a bus 180. The control unit 110 includes a processor such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), or DSP (Digital Signal Processor). The control unit 110 may be configured by combining two or more of the above processors, or may be configured as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0014] The RAM 120 is used as a work area for the control unit 110. The ROM 130 stores a system program. The storage unit 140 includes a storage medium such as a hard disk or a semiconductor memory, and stores a prediction program. The prediction program is a computer program for executing a prediction process that predicts a pattern collapse rate during substrate processing by the processing unit 200.

[0015] The prediction program may be stored in ROM 130. Alternatively, the prediction program may be provided in a form stored in a computer-readable storage medium 190 such as a CD (compact disc)-ROM or an SD memory card, and may be installed in storage unit 140 or ROM 130 by being read out via input / output I / F 170 or the like. Furthermore, if input / output I / F 170 is connected to a communication network, a prediction program distributed from a server connected to the communication network may be installed in storage unit 140 or ROM 130.

[0016] The operation unit 150 is an input device such as a keyboard, mouse, or touch panel. By operating the operation unit 150, a user can store predetermined information used in the prediction process, such as a reference light reception signal or a trained model (described later), in the storage unit 140 in advance. The display unit 160 is a display device such as a liquid crystal display device, and is capable of displaying the results of the prediction process, etc. The input / output I / F 170 is connected to the processing unit 200. This allows the information processing device 100 to acquire various information from the processing unit 200 and to issue control commands to the processing unit 200.

[0017] The processing unit 200 processes the substrate by supplying a processing solution to the substrate under set processing conditions. In this example, the substrate processing is a sublimation drying process. Specifically, the processing unit 200 applies a processing solution in which a sublimable substance is dissolved in a solvent to the surface of the substrate on which a pattern has been formed, and then performs a series of processes in which the solvent is evaporated while the substrate is rotated, thereby precipitating the sublimable substance on the substrate. The processing unit 200 then sublimes and dries the sublimable substance by blowing an inert gas onto the substrate. The sublimable substance includes, for example, pinacoline oxime or cyclohexanone oxime. The solvent includes, for example, isopropyl alcohol.

[0018] 2. Processing Unit FIG. 2 is a schematic cross-sectional view showing the configuration of the processing unit 200. As shown in FIG. 2, the processing unit 200 includes a control unit 210, a processing chamber 220, a spin holder 230, a processing liquid supply unit 240, a gas supply unit 250, and a measurement unit 260. The control unit 210 includes, for example, a processor and a memory. The processor of the control unit 210 may have a configuration similar to that of the control unit 110 of the information processing device 100 in FIG. 1. A sublimation drying program for executing a sublimation drying process is stored in the memory of the control unit 210. The control unit 210 controls the operations of the spin holder 230, the processing liquid supply unit 240, the gas supply unit 250, and the measurement unit 260 in accordance with the sublimation drying program.

[0019] The processing chamber 220 defines a processing space therein for processing the substrate W. The processing chamber 220 is provided with windows 221 and 222 that face each other across the processing space. The windows 221 and 222 are made of a material that has high transmittance over a wide wavelength range, including the ultraviolet and infrared ranges. In this example, the windows 221 and 222 are made of calcium fluoride glass or sapphire glass.

[0020] The rotation holder 230 includes a spin motor 231 and a spin chuck 232. The spin motor 231 has a rotation shaft. In FIG. 2 , only the rotation shaft of the spin motor 231 is shown, and the main body of the spin motor 231 is not shown. The main body of the spin motor 231 is disposed below the processing chamber 220 so that the rotation shaft faces upward. The upper part of the rotation shaft of the spin motor 231 is located inside the processing chamber 220.

[0021] The spin chuck 232 is housed inside the processing chamber 220 and attached to the upper end of the rotation shaft of the spin motor 231. The spin chuck 232 holds the back surface of the substrate W in a substantially horizontal position with the main surface of the substrate W facing upward. Therefore, the spin chuck 232 rotates the substrate W around a vertical axis when the rotation shaft of the spin motor 231 is rotationally driven.

[0022] The processing liquid supply unit 240 includes a processing liquid nozzle that discharges the processing liquid, and is housed inside the processing chamber 220. The processing liquid supply unit 240 supplies the processing liquid to approximately the center of the main surface of the substrate W held by the spin chuck 232. The processing liquid supplied to approximately the center of the main surface of the substrate W is spread over the entire main surface of the substrate W as the substrate W rotates. As a result, a liquid film of the processing liquid is formed on the main surface of the substrate W. The processing liquid supply unit 240 also includes a removing liquid nozzle that discharges a removing liquid. The removing liquid is a chemical liquid for removing a liquid film formed on the main surface of the substrate W, and is supplied to the main surface of the substrate W based on a command from the information processing apparatus 100.

[0023] The gas supply unit 250 is housed inside the processing chamber 220 and supplies gas to the processing space. The gas is, for example, nitrogen gas, but may be another inert gas. Alternatively, the gas may be clean air. By supplying gas to the processing space at a relatively small flow rate, the solvent evaporates from the liquid film formed on the main surface of the substrate W. In this case, a solidified film containing a sublimable substance is formed on the main surface of the substrate W. Furthermore, by supplying gas to the processing space at a relatively large flow rate, the solidified film formed on the main surface of the substrate W sublimes. As a result, the solidified film is removed from the main surface of the substrate W.

[0024] The measurement unit 260 includes a light-projecting unit 261, light-receiving units 262 and 263, optical fibers 264 and 265, and collimating lenses 266 and 267, and is disposed outside the processing chamber 220. The light-projecting unit 261 includes a light source and emits light containing components in the ultraviolet and infrared regions. In this example, the light source is a deuterium halogen lamp. The light-receiving units 262 and 263 each include a spectroscope and a light-receiving element. The light-receiving unit 262 receives light of a specific wavelength in the ultraviolet region and outputs a light-receiving signal indicating the amount of received light. The light-receiving unit 263 receives light of a specific wavelength in the infrared region and outputs a light-receiving signal indicating the amount of received light.

[0025] The optical fiber 264 optically connects the light projecting unit 261 and the collimating lens 266. The optical fiber 265 is a bifurcated fiber, and optically connects the light receiving units 262 and 263 and the collimating lens 267. Specifically, the optical fiber 265 has first to third ends. The first to third ends of the optical fiber 265 are connected to the collimating lens 267, the light receiving unit 262, and the light receiving unit 263, respectively.

[0026] In this example, light is continuously emitted from the light-projecting unit 261 over a predetermined period for evaporating the solvent. The light emitted by the light-projecting unit 261 is collimated through the optical fiber 264 and the collimating lens 266. The collimated light passes through the window 221 and is guided into the processing chamber 220, where it is irradiated onto the main surface of the substrate W on which the liquid film has been formed. The light irradiated onto the main surface of the substrate W is reflected by the main surface of the substrate W, passes through the window 222, and is guided to the outside of the processing chamber 220. The light guided to the outside of the processing chamber 220 passes through the collimating lens 267 and is input to the optical fiber 265 from a first end.

[0027] A portion of the light input to the optical fiber 265 is output from the second end and enters the light receiving unit 262. The light input to the light receiving unit 262 is split by a spectroscope, and light with a specific wavelength in the ultraviolet region is received by a light receiving element. The remaining portion of the light input to the optical fiber 265 is output from the third end and enters the light receiving unit 263. The light input to the light receiving unit 263 is split by a spectroscope, and light with a specific wavelength in the infrared region is received by the light receiving element. As a result, a light receiving signal is output from the light receiving units 262, 263. The amount of received light indicated by the light receiving signal corresponds to the intensity of light irradiated onto the liquid film on the substrate W. The light receiving signals output by the light receiving units 262, 263 are provided to the information processing apparatus 100, for example, via the control unit 210.

[0028] Furthermore, in the processing unit 200, a preliminary measurement is performed before the execution of the prediction process described below. In the preliminary measurement, a liquid film is formed on the substrate W by the processing liquid supply unit 240 using a processing liquid whose solvent does not contain a sublimable substance. The light projector 261 irradiates the substrate W with light, causing each of the light receivers 262, 263 to output a light reception signal. The light reception signals output by each of the light receivers 262, 263 in the preliminary measurement are called reference light reception signals. The reference light reception signals output by the light receivers 262, 263 over a predetermined period are stored in the memory unit 140 or the like of the information processing device 100.

[0029] In the preliminary measurement, the wavelength of light received by the light receiving units 262 and 263 may be determined. Specifically, light of multiple wavelengths in the ultraviolet region is received by the light receiving unit 262, and a graph showing the relationship between wavelength in the ultraviolet region and the amount of received light (light intensity) is generated. In the graph, wavelengths in the ultraviolet region where the change in the amount of received light is significant are determined as the wavelength of light in the ultraviolet region to be received by the light receiving unit 262 in the prediction process. A similar preliminary measurement is also performed on the light receiving unit 263, and the wavelength of light in the infrared region to be received by the light receiving unit 262 in the prediction process is determined.

[0030] 3. Information Processing Device Fig. 3 is a block diagram showing the functional configuration of the information processing device 100. As shown in Fig. 3, the information processing device 100 includes, as a functional unit 10, a light intensity acquisition unit 11, a transmittance acquisition unit 12, an absorbance acquisition unit 13, a thickness acquisition unit 14, a concentration acquisition unit 15, a prediction unit 16, and an output unit 17. The functional unit 10 of the information processing device 100 is realized by the control unit 110 of Fig. 1 executing a prediction program. Part or all of the functional unit 10 of the information processing device 100 may be realized by hardware such as an electronic circuit.

[0031] The light intensity acquisition unit 11 continuously acquires in real time from the processing unit 200 the light reception signals output by the light receiving unit 262 in Fig. 2. This allows the intensity of light in the ultraviolet region irradiated onto the liquid film on the substrate W at multiple points in time, i.e., the change over time of the intensity of light in the ultraviolet region. Similarly, the light intensity acquisition unit 11 continuously acquires in real time from the processing unit 200 the light reception signals output by the light receiving unit 263 in Fig. 2. This allows the intensity of light in the infrared region irradiated onto the liquid film on the substrate W at multiple points in time, i.e., the change over time of the intensity of light in the infrared region.

[0032] The transmittance acquisition unit 12 acquires the ultraviolet transmittance of the liquid film at multiple time points, i.e., the time change of the ultraviolet transmittance of the liquid film, based on the time change of the intensity of ultraviolet light acquired by the light intensity acquisition unit 11 and the time change of the reference ultraviolet light reception signal stored in the memory unit 140 or the like. The ultraviolet transmittance at each time point is acquired by dividing the intensity of ultraviolet light at each time point by the amount of light received in the reference ultraviolet light reception signal at the same time point. Similarly, the transmittance acquisition unit 12 acquires the time change of the infrared transmittance of the liquid film based on the time change of the intensity of infrared light acquired by the light intensity acquisition unit 11 and the time change of the reference infrared light reception signal stored in the memory unit 140 or the like.

[0033] The absorbance acquisition unit 13 acquires the absorbance in the ultraviolet region of the liquid film at multiple time points, i.e., the time change in the absorbance in the ultraviolet region of the liquid film, based on the time change in the transmittance in the ultraviolet region acquired by the transmittance acquisition unit 12. If the transmittance in the ultraviolet region at each time point is T, the absorbance A in the ultraviolet region at each time point is expressed as A = -log １０ Similarly, the absorbance acquisition unit 13 acquires the time change in the absorbance of the liquid film in the infrared region based on the time change in the transmittance in the infrared region acquired by the transmittance acquisition unit 12.

[0034] The thickness acquisition unit 14 acquires the thickness of the liquid film at multiple points in time, i.e., the time change in the thickness of the liquid film, based on the time change in the absorbance of the liquid film in the infrared region acquired by the absorbance acquisition unit 13. In the infrared region, the absorbance of the solvent is dominant over the absorbance of the sublimable substance. For example, in the infrared region, when the supply of the processing liquid to the substrate W begins, the absorbance increases. Thereafter, as time passes, the absorbance gradually decreases as the solvent evaporates, and reaches approximately zero when the evaporation of the solvent is completed. In this way, the time change in absorbance indicates the time change in the thickness of the liquid film. Therefore, the absorbance in the infrared region is correlated with the thickness of the liquid film so that the thickness of the liquid film converted from the amount of processing liquid supplied and the diameter of the substrate W corresponds to the maximum value of the absorbance in the infrared region. In this way, the time change in the thickness of the liquid film is acquired.

[0035] The concentration acquisition unit 15 acquires the concentration of the sublimable substance at multiple points in time, i.e., the time change of the concentration of the sublimable substance, based on the time change of the absorbance in the ultraviolet region acquired by the absorbance acquisition unit 13 and the time change of the thickness of the liquid film acquired by the thickness acquisition unit 14. The concentration at each point in time is acquired by dividing the absorbance at each point in time by the thickness (optical path length) of the liquid film at the same point in time, in accordance with the Beer-Lambert law. In this way, the light intensity acquisition unit 11, the transmittance acquisition unit 12, the absorbance acquisition unit 13, the thickness acquisition unit 14, and the concentration acquisition unit 15 constitute an acquisition unit for acquiring the time change of the concentration of the sublimable substance.

[0036] The prediction unit 16 uses the trained model to predict the pattern collapse rate when the solidified film is sublimated from the change over time in the concentration of the sublimable substance acquired by the concentration acquisition unit 15. The trained model is a machine learning model that has learned the relationship between the change over time in the concentration of the sublimable substance and the pattern collapse rate, and is stored in advance in, for example, the storage unit 140. The trained model is generated by the machine learning model learning using the substrate processing recipe and the change over time in the concentration of the sublimable substance as explanatory variables and the pattern collapse rate as a target variable. The trained model may be generated by the information processing device 100 or may be generated by a device other than the information processing device 100 (for example, a cloud server, etc.).

[0037] If the collapse rate predicted by the prediction unit 16 is equal to or greater than a predetermined threshold, the output unit 17 outputs a process using the prediction result before sublimating the solidified film. As an example of the output of the process using the prediction result by the output unit 17, a character string indicating that the pattern collapse rate is predicted to be high may be displayed on the display unit 160. If the information processing device 100 includes an audio output device, a voice indicating the same content may be output, or a warning sound such as a buzzer may be output. If the information processing device 100 includes an indicator light such as a lamp, the indicator light may be turned on, off, or flashing in a manner corresponding to the same content. In these cases, the user can recognize that a large number of patterns will collapse when the solidified film is sublimated.

[0038] As another example of output of a process using the prediction result by the output unit 17, the output unit 17 may issue a control command to the control unit 210 of the processing unit 200 in Figure 2 to perform a recovery process that prevents the formation of a solidified film. The recovery process may be a first recovery process that additionally supplies a processing liquid onto the liquid film formed on the main surface of the substrate W, or a second recovery process that supplies a removal liquid onto the liquid film formed on the main surface of the substrate W to remove the liquid film. In these cases, preventing the formation of a solidified film prevents the collapse of the pattern. After the recovery process is performed, the processing of the substrate W is performed again.

[0039] 4. Substrate Processing The substrate processing in the substrate processing apparatus 300 includes a sublimation drying process, which is a process for a substrate W executed by the processing unit 200, and a prediction process executed by the information processing apparatus 100. FIG. 4 is a block diagram showing the functional configuration of the processing unit 200. As shown in FIG. 4, the processing unit 200 includes, as functional sections 20, a liquid film forming section 21, a solidified film forming section 22, a measurement execution section 23, a recovery execution section 24, and a sublimation execution section 25. The functional sections 20 of the processing unit 200 are realized by the control section 110 of FIG. 2 executing a sublimation drying program. Part or all of the functional sections 20 of the processing unit 200 may be realized by hardware such as electronic circuits.

[0040] FIG. 5 is a flowchart showing an example of the flow of sublimation drying processing by the processing unit 200. The sublimation drying processing of FIG. 5 will be described below with reference to the processing unit 200 of FIG. 4 . First, the liquid film forming unit 21 controls the processing liquid supply unit 240 to supply the processing liquid to the main surface of the substrate W (step S1). At this time, the liquid film forming unit 21 may control the spin holder 230 to rotate the substrate W at a relatively low speed (e.g., 10 rpm or less). Next, the liquid film forming unit 21 controls the spin holder 230 to increase the rotation speed of the substrate W, thereby diffusing the processing liquid to form a liquid film on the main surface of the substrate W (step S2). At this time, the rotation speed of the substrate W is, for example, 10 rpm or more and 100 rpm or less.

[0041] Next, the solidified film forming unit 22 evaporates the solvent from the liquid film formed on the main surface of the substrate W by controlling the gas supply unit 250 to supply gas at a relatively small flow rate while controlling the spin holder 230 to further increase the rotation speed of the substrate W (step S3). The rotation speed of the substrate W at this time is, for example, not less than 500 rpm and not more than 1500 rpm. During the execution of step S3, the measurement executing unit 23 controls the measuring unit 260 to measure the behavior of the liquid film formed on the main surface of the substrate W (step S4). Specifically, the measurement executing unit 23 continuously acquires light reception signals output by the light receiving units 262 and 263 shown in FIG. 2 and provides the signals to the information processing device 100.

[0042] Thereafter, the recovery execution unit 24 determines whether or not a first recovery process has been commanded by the information processing apparatus 100 (step S5). If the first recovery process has been commanded, the recovery execution unit 24 controls the processing liquid supply unit 240 to additionally supply processing liquid to the main surface of the substrate W (step S6). At this time, the liquid film formation unit 21 may rotate the substrate W at a relatively low speed (for example, 10 rpm or less) by controlling the spin holding unit 230. Thereafter, the process returns to step S2.

[0043] If the first recovery process is not commanded in step S5, the recovery execution unit 24 determines whether the second recovery process has been commanded by the information processing apparatus 100 (step S7). If the second recovery process has been commanded, the recovery execution unit 24 controls the processing liquid supply unit 240 to supply the removal liquid to the main surface of the substrate W (step S8). At this time, the liquid film formation unit 21 may rotate the substrate W at a relatively low speed (e.g., 10 rpm or less) by controlling the spin holding unit 230. Thereafter, the process returns to step S1.

[0044] If the second recovery process is not commanded in step S7, the solvent evaporates in step S3, thereby forming a solidified film on the main surface of the substrate W. Finally, the sublimation execution unit 25 controls the gas supply unit 250 to supply gas at a relatively high flow rate, thereby sublimating the solidified film formed on the main surface of the substrate W (step S9). The rotation speed of the substrate W at this time is maintained at the rotation speed in step S3 (e.g., not less than 500 rpm and not more than 1500 rpm). In this case, the solidified film is removed from the main surface of the substrate W. This completes the sublimation drying process.

[0045] Fig. 6 is a flowchart showing an example of the flow of a prediction process by the information processing device 100. The prediction process is a process executed by the control unit 110 of the information processing device 100 as the control unit 110 executes a prediction program. In this example, the prediction process is executed in response to the processing unit 200 executing step S4 of the sublimation drying process in Fig. 5. The prediction process in Fig. 6 will be described below with reference to the information processing device 100 in Fig. 3.

[0046] First, the light intensity acquisition unit 11 acquires the time change in light intensity by continuously receiving light reception signals in real time from the processing unit 200 (step S11). The light intensity includes the intensity of light in the ultraviolet region and the intensity of light in the infrared region. Next, the transmittance acquisition unit 12 acquires the time change in the transmittance of the liquid film based on the time change in light intensity acquired in step S11 (step S12). The transmittance of the liquid film includes the transmittance of the liquid film in the ultraviolet region and the transmittance of the liquid film in the infrared region. A reference light reception signal stored in the memory unit 140 or the like is used to acquire the transmittance of the liquid film at each time point.

[0047] Next, the absorbance acquisition unit 13 acquires the time change in absorbance of the liquid film based on the time change in transmittance acquired in step S12 (step S13). The absorbance of the liquid film includes the absorbance of the liquid film in the ultraviolet region and the absorbance of the liquid film in the infrared region. Thereafter, the thickness acquisition unit 14 acquires the time change in the thickness of the liquid film based on the time change in the absorbance of the liquid film in the infrared region acquired in step S13 (step S14).

[0048] Next, the concentration acquisition unit 15 acquires the time change in the concentration of the sublimable substance based on the time change in absorbance in the ultraviolet region acquired in step S13 and the time change in the thickness of the liquid film acquired in step S14 (step S15). Subsequently, the prediction unit 16 predicts the pattern collapse rate when the solidified film is sublimated based on the time change in the concentration of the sublimable substance acquired in step S15 (step S16). The prediction of the pattern collapse rate uses a trained model stored in the storage unit 140 or the like.

[0049] Thereafter, the output unit 17 determines whether the pattern corruption rate predicted in step S16 is equal to or greater than a first threshold value (step S17). The first threshold value is, for example, 5%. If the pattern corruption rate is less than the first threshold value, the output unit 17 terminates the prediction process. If the pattern corruption rate is equal to or greater than the first threshold value, the output unit 17 determines whether the pattern corruption rate is equal to or greater than a second threshold value (step S18). The second threshold value is greater than the first threshold value, for example, 10%.

[0050] If the pattern collapse rate is less than the second threshold value, the output unit 17 commands the processing unit 200 to perform the first recovery process (step S19) and ends the prediction process. In this case, it is determined that the first recovery process has been commanded in step S5 of the sublimation drying process in FIG. 5 . As a result, the first recovery process is executed in the processing unit 200. If the pattern collapse rate is equal to or greater than the second threshold value, the output unit 17 commands the processing unit 200 to perform the second recovery process (step S20) and ends the prediction process. In this case, it is determined that the second recovery process has been commanded in step S7 of the sublimation drying process in FIG. 5 . As a result, the second recovery process is executed in the processing unit 200.

[0051] 5. Effects The information processing apparatus 100 according to this embodiment is used together with the processing unit 200. In the processing unit 200, a processing liquid containing a sublimable substance and a solvent is supplied to the main surface of the substrate W on which a pattern has been formed, thereby forming a liquid film of the processing liquid. The solvent is evaporated from the formed liquid film, thereby forming a solidified film containing the sublimable substance on the main surface. The solidified film is removed from the main surface by sublimation.

[0052] During the period in which the solvent is evaporated in the processing unit 200, the concentration acquisition unit 15 or the like acquires a time change in concentration indicating a time change in the concentration of the sublimable substance based on the absorbance of the liquid film formed on the main surface in the information processing device 100. The prediction unit 16 predicts the pattern collapse rate when the solidified film is sublimated based on the time change in concentration acquired by the concentration acquisition unit 15 or the like. If the collapse rate predicted by the prediction unit 16 is equal to or greater than a predetermined threshold, the output unit 17 outputs the prediction result before the solidified film is sublimated. In this case, measures can be taken to reduce pattern collapse according to the output by the output unit 17. This makes it possible to reduce pattern collapse during sublimation drying.

[0053] The output unit 17 outputs the prediction result by executing a recovery process that prevents the formation of a solidified film. According to this configuration, if the predicted pattern collapse rate is equal to or greater than a threshold, the recovery process is executed to prevent the formation of a solidified film. This reduces pattern collapse during sublimation drying. Specifically, the output unit 17 executes the first recovery process by further supplying a processing liquid onto the liquid film formed on the main surface. Alternatively, the output unit 17 may execute the second recovery process by supplying a removal liquid onto the liquid film formed on the main surface to remove the liquid film. In these cases, the formation of a solidified film can be easily prevented in each of the first and second recovery processes.

[0054] The prediction unit 16 predicts the collapse rate using a trained model that has learned the relationship between the time change in the concentration of the sublimable substance and the collapse rate. In this case, the collapse rate of the pattern can be easily predicted from the time change in the concentration of the sublimable substance.

[0055] The absorbance includes a first absorbance at a first wavelength and a second absorbance at a second wavelength longer than the first wavelength. The thickness of the liquid film is obtained based on the second absorbance of the liquid film. The concentration of the sublimable substance is calculated based on the first absorbance of the liquid film and the thickness of the liquid film, thereby obtaining a change in concentration over time. In this case, the concentration of the sublimable substance can be easily quantified. In this example, the first wavelength is in the ultraviolet region, and the second wavelength is in the infrared region. In this case, the absorbance corresponding to the concentration of the sublimable substance can be more easily obtained as the first absorbance. Furthermore, the thickness of the liquid film can be more easily obtained based on the second absorbance. This makes it easier to quantify the concentration of the sublimable substance.

[0056] 6. First Modification In this embodiment, the behavior of a portion of the liquid film formed on the main surface of the substrate W is measured by the measurement unit 260, but the embodiment is not limited to this. In the first modification, the behavior of multiple portions of the liquid film formed on the main surface of the substrate W is measured by the measurement unit 260. For example, the light projecting unit 261 and the light receiving units 262, 263 may be scanned during measurement while maintaining their relative positional relationship so that light is irradiated onto multiple portions of the liquid film formed on the main surface of the substrate W. In this case, the behavior of multiple portions of the liquid film is measured.

[0057] Alternatively, a plurality of pairs of light-projecting unit 261 and light-receiving units 262, 263 may be provided. In this case, the plurality of light-projecting units 261 irradiate light onto a plurality of portions of the liquid film formed on the main surface of the substrate W, respectively. Furthermore, the light reflected by the plurality of portions of the liquid film formed on the main surface of the substrate W is received by the plurality of light-receiving units 262, 263, respectively. Even in this case, the behavior of a plurality of portions of the liquid film is measured.

[0058] In these configurations, the change over time in the concentration of the sublimable substance at a plurality of portions of the main surface of the substrate W, i.e., the spatial distribution of the change over time in the concentration of the sublimable substance, is acquired by the light intensity acquisition unit 11, the transmittance acquisition unit 12, the absorbance acquisition unit 13, the thickness acquisition unit 14, and the concentration acquisition unit 15. Therefore, by using a machine learning model that has learned the relationship between the spatial distribution of the change over time in the concentration of the sublimable substance and the collapse rate of the pattern, it is possible to more accurately predict the collapse rate of the pattern when the solidified film is sublimated, based on the spatial distribution of the change over time in the concentration of the sublimable substance.

[0059] 7. Second Modification In this embodiment, the measuring unit 260 is disposed outside the processing chamber 220, but the embodiment is not limited to this. The measuring unit 260 may be disposed inside the processing chamber 220. In this case, the processing chamber 220 does not need to be provided with the windows 221 and 222. Furthermore, when the measuring unit 260 is disposed inside the processing chamber 220, at least a part of the optical path for light projection and the optical path for light reception may be common.

[0060] FIG. 7 is a diagram showing an example of a measuring unit 260 in the second modified example. As shown in FIG. 7, the measuring unit 260 includes an optical fiber 268 instead of the optical fibers 264 and 265, and a collimating lens 269 instead of the collimating lenses 266 and 267. The optical fiber 268 is a trifurcated fiber that optically connects the light-projecting unit 261 and the light-receiving units 262 and 263 to the collimating lens 269. Specifically, the optical fiber 268 has first to fourth ends. The first to fourth ends of the optical fiber 268 are connected to the collimating lens 269, the light-projecting unit 261, the light-receiving unit 262, and the light-receiving unit 263, respectively. The collimating lens 269 is disposed above the substrate W so that its optical axis is parallel to the vertical direction.

[0061] According to this arrangement, the light emitted by the light-projecting unit 261 is input to the optical fiber 268 from the second end. The light input to the optical fiber 268 is output from the first end and collimated through the collimating lens 269. The collimated light is irradiated from directly above onto the main surface of the substrate W on which the liquid film has been formed. The light irradiated onto the main surface of the substrate W is reflected directly upward by the main surface of the substrate W, and input to the optical fiber 268 from the first end through the collimating lens 269. A portion of the light input to the optical fiber 268 is output from the third end and enters the light-receiving unit 262. The remaining portion of the light input to the optical fiber 268 is output from the fourth end and enters the light-receiving unit 263.

[0062] 8. Other Embodiments (1) In the above embodiment, the prediction unit 16 predicts the pattern collapse rate from the time change in the concentration of the sublimable substance using a trained model, but the embodiment is not limited to this. The prediction unit 16 may predict the pattern collapse rate from the time change in the concentration of the sublimable substance using another method. For example, the prediction unit 16 may predict the pattern collapse rate from the time change in the concentration of the sublimable substance using information indicating the correspondence relationship between the time change in the concentration of the sublimable substance and the collapse rate.

[0063] (2) In the above embodiment, the output unit 17 outputs the prediction result using the display unit 160 or the like, but the embodiment is not limited to this. The output unit 17 does not need to output the prediction result using the display unit 160 or the like as long as it is possible to issue a control command to the control unit 210 of the processing unit 200 to execute recovery processing. On the other hand, if the output unit 17 is able to output the prediction result using the display unit 160 or the like, it does not need to issue a control command to the control unit 210 of the processing unit 200 to execute recovery processing.

[0064] (3) In the above embodiment, the substrate processing apparatus 300 includes one processing unit 200. However, the embodiment is not limited to this. The substrate processing apparatus 300 may include multiple processing units 200. In this case, a common trained model capable of predicting the pattern collapse rates in the multiple processing units 200 may be generated, or multiple trained models capable of predicting the pattern collapse rates in the multiple processing units 200 may be generated.

[0065] (4) In the above embodiment, the information processing apparatus 100 is provided as a part of the substrate processing apparatus 300, but the embodiment is not limited to this. The information processing apparatus 100 may be provided as a separate entity from the substrate processing apparatus 300.

[0066] 9. Correspondence between each component of the claims and each part of the embodiment Examples of correspondence between each component of the claims and each element of the embodiment are described below, but the present invention is not limited to the following examples. Various other elements having the configuration or function described in the claims may also be used as each component of the claims. In the above embodiment, the substrate W is an example of a substrate, the information processing device 100 is an example of an information processing device, the light intensity acquisition unit 11, the transmittance acquisition unit 12, the absorbance acquisition unit 13, the thickness acquisition unit 14, and the concentration acquisition unit 15 are examples of acquisition units, the prediction unit 16 is an example of a prediction unit, and the output unit 17 is an example of an output unit.

[0067] 10. Summary of Embodiments (Item 1) A substrate processing method according to item 1 is a computer-executed substrate processing method for supplying a processing liquid containing a sublimable substance and a solvent onto a main surface of a substrate on which a pattern has been formed, thereby forming a liquid film of the processing liquid, evaporating the solvent from the formed liquid film to form a solidified film containing the sublimable substance on the main surface, and removing the solidified film from the main surface by sublimating it, the method comprising: acquiring a change over time in concentration of the sublimable substance based on absorbance of the liquid film formed on the main surface during a period in which the solvent is evaporated; predicting a collapse rate of the pattern when the solidified film is sublimated based on the acquired change over time in concentration; and, if the predicted collapse rate is equal to or greater than a predetermined threshold, outputting a process using the prediction result before sublimating the solidified film.

[0068] According to this substrate processing method, the rate of pattern collapse when a solidified film is sublimated is predicted based on the time change in concentration of a sublimable substance during the period in which a solvent is evaporated during sublimation drying of a substrate. If the predicted rate of pattern collapse is equal to or greater than a threshold, processing using the prediction result is output before the solidified film is sublimated. In this case, measures to reduce pattern collapse can be taken according to the output result. This makes it possible to reduce pattern collapse during sublimation drying.

[0069] (Item 2) In the substrate processing method described in Item 1, outputting the processing using the prediction result may include executing a recovery processing to prevent the formation of the solidified film.

[0070] According to this configuration, if the predicted pattern collapse rate is equal to or greater than the threshold value, the recovery process is executed to prevent the formation of a solidified film, thereby reducing pattern collapse during sublimation drying.

[0071] (Item 3) In the substrate processing method described in Item 2, performing the recovery process may include additionally supplying the processing liquid onto the liquid film formed on the main surface.

[0072] In this case, the formation of a solidified film can be easily prevented in the recovery process.

[0073] (4) In the substrate processing method described in (2), performing the recovery process may include supplying a removal liquid onto the liquid film formed on the main surface to remove the liquid film.

[0074] In this case, the formation of a solidified film can be easily prevented in the recovery process.

[0075] (5) In the substrate processing method described in any one of paragraphs 1 to 4, predicting the collapse rate may include predicting the collapse rate using a trained model that has learned the relationship between the time change in concentration of the sublimable substance and the collapse rate.

[0076] In this case, the rate of pattern collapse can be easily predicted from the change in concentration of the sublimable substance over time.

[0077] (Item 6) In the substrate processing method described in any one of Items 1 to 5, the absorbance may include a first absorbance at a first wavelength and a second absorbance at a second wavelength longer than the first wavelength, and acquiring the change in concentration over time may include acquiring a thickness of the liquid film based on the second absorbance of the liquid film, and calculating the concentration of the sublimable substance based on the first absorbance of the liquid film and the thickness of the liquid film.

[0078] In this case, the concentration of the sublimable substance can be easily quantified.

[0079] (Item 7) In the substrate processing method described in Item 6, the first wavelength may be in the ultraviolet region, and the second wavelength may be in the infrared region.

[0080] In this case, the absorbance corresponding to the concentration of the sublimable substance can be more easily obtained as the first absorbance, and the thickness of the liquid film can be more easily obtained based on the second absorbance, thereby making it easier to quantify the concentration of the sublimable substance.

[0081] (Item 8) In the substrate processing method described in any one of Items 1 to 7, acquiring the change in concentration over time may include acquiring a spatial distribution of the change in concentration over time on the main surface, and predicting the collapse rate may include predicting the collapse rate when the solidified film is sublimated based on the spatial distribution of the change in concentration over time.

[0082] In this case, the rate of pattern collapse when the solidified film is sublimated can be predicted more accurately.

[0083] (Item 9) An information processing device according to item 9 is an information processing device used for substrate processing, which forms a liquid film of a processing liquid containing a sublimable substance and a solvent by supplying the processing liquid to a main surface of a substrate on which a pattern is formed, forms a solidified film containing the sublimable substance on the main surface by evaporating the solvent from the formed liquid film, and removes the solidified film from the main surface by sublimating it, and is equipped with: an acquisition unit that acquires a change in concentration over time indicating a change in concentration of the sublimable substance over time based on the absorbance of the liquid film formed on the main surface during a period in which the solvent is evaporating; a prediction unit that predicts a collapse rate of the pattern when the solidified film is sublimated based on the change in concentration over time acquired by the acquisition unit; and an output unit that outputs processing using the prediction result before sublimating the solidified film if the collapse rate predicted by the prediction unit is equal to or greater than a predetermined threshold.

[0084] In this information processing device, the pattern collapse rate when the solidified film is sublimated is predicted based on the time change in concentration of the sublimable substance during the period in which the solvent is evaporated during sublimation drying of the substrate. If the predicted pattern collapse rate is equal to or greater than a threshold, processing using the prediction result is output before the solidified film is sublimated. In this case, measures to reduce pattern collapse can be taken according to the output result. This makes it possible to reduce pattern collapse during sublimation drying.

[0085] (Item 10) In the information processing device described in item 9, the output unit may output a process using the prediction result by executing a recovery process that prevents the formation of the solidified film.

[0086] According to this configuration, if the predicted pattern collapse rate is equal to or greater than the threshold value, the recovery process is executed to prevent the formation of a solidified film, thereby reducing pattern collapse during sublimation drying.

[0087] (Item 11) In the information processing device described in Item 10, the output section may perform the recovery process by further supplying the processing liquid onto the liquid film formed on the main surface.

[0088] In this case, the formation of a solidified film can be easily prevented in the recovery process.

[0089] (Item 12) In the information processing device described in Item 10, the output unit may perform the recovery process by supplying a removal liquid onto the liquid film formed on the main surface to remove the liquid film.

[0090] In this case, the formation of a solidified film can be easily prevented in the recovery process.

[0091] (Item 13) In the information processing device described in any one of Items 9 to 12, the prediction unit may predict the collapse rate using a trained model that has learned the relationship between the time change in concentration of the sublimable substance and the collapse rate.

[0092] In this case, the rate of pattern collapse can be easily predicted from the change in concentration of the sublimable substance over time.

[0093] (Item 14) In the information processing device described in any one of items 9 to 13, the absorbance includes a first absorbance at a first wavelength and a second absorbance at a second wavelength longer than the first wavelength, and the acquisition unit may acquire a thickness of the liquid film based on the second absorbance of the liquid film, and acquire a change in concentration over time by calculating the concentration of the sublimable substance based on the first absorbance of the liquid film and the thickness of the liquid film.

[0094] In this case, the concentration of the sublimable substance can be easily quantified.

[0095] (Item 15) In the information processing device described in item 14, the first wavelength may be in the ultraviolet region, and the second wavelength may be in the infrared region.

[0096] In this case, the absorbance corresponding to the concentration of the sublimable substance can be more easily obtained as the first absorbance, and the thickness of the liquid film can be more easily obtained based on the second absorbance, thereby making it easier to quantify the concentration of the sublimable substance.

[0097] (Item 16) In the information processing device described in any one of items 9 to 15, the acquisition unit may acquire a spatial distribution of the change in concentration over time on the main surface, and the prediction unit may predict the collapse rate when the solidified film is sublimated based on the spatial distribution of the change in concentration over time acquired by the acquisition unit.

[0098] In this case, the rate of pattern collapse when the solidified film is sublimated can be predicted more accurately.

Claims

1. A substrate processing method executed by a computer in which a processing liquid containing a sublimable substance and a solvent is supplied to a main surface of a substrate on which a pattern has been formed, thereby forming a liquid film of the processing liquid, the solvent being evaporated from the formed liquid film to form a solidified film containing the sublimable substance on the main surface, and the solidified film is removed from the main surface by sublimating it, the substrate processing method comprising: acquiring a change over time in concentration of the sublimable substance based on the absorbance of the liquid film formed on the main surface during a period in which the solvent is evaporated; predicting a collapse rate of the pattern when the solidified film is sublimated based on the acquired change over time in concentration; and if the predicted collapse rate is equal to or greater than a predetermined threshold, outputting a process using the predicted result before sublimating the solidified film.

2. The substrate processing method according to claim 1, wherein outputting a process using the prediction result includes executing a recovery process to prevent the formation of the solidified film.

3. The substrate processing method according to claim 2, wherein performing the recovery process includes additionally supplying the processing liquid onto the liquid film formed on the main surface.

4. The substrate processing method according to claim 2, wherein the recovery process includes supplying a remover onto the liquid film formed on the main surface to remove the liquid film.

5. A substrate processing method according to any one of claims 1 to 4, wherein predicting the collapse rate includes predicting the collapse rate using a trained model that has learned the relationship between the time change in concentration of the sublimable substance and the collapse rate.

6. A substrate processing method according to any one of claims 1 to 5, wherein the absorbance includes a first absorbance at a first wavelength and a second absorbance at a second wavelength longer than the first wavelength, and acquiring the change in concentration over time includes acquiring a thickness of the liquid film based on the second absorbance of the liquid film, and calculating the concentration of the sublimable substance based on the first absorbance of the liquid film and the thickness of the liquid film.

7. A method for processing a substrate according to claim 6, wherein said first wavelength is in the ultraviolet region and said second wavelength is in the infrared region.

8. A substrate processing method according to any one of claims 1 to 7, wherein acquiring the change in concentration over time includes acquiring a spatial distribution of the change in concentration over time on the main surface, and predicting the collapse rate includes predicting the collapse rate when the solidified film is sublimated based on the spatial distribution of the change in concentration over time.

9. An information processing device used in substrate processing, which forms a liquid film of a processing liquid containing a sublimable substance and a solvent by supplying the processing liquid to a main surface of a substrate on which a pattern has been formed, forms a solidified film containing the sublimable substance on the main surface by evaporating the solvent from the formed liquid film, and removes the solidified film from the main surface by sublimating it, comprising: an acquisition unit that acquires a change in concentration of the sublimable substance over time based on the absorbance of the liquid film formed on the main surface during a period in which the solvent is evaporating; a prediction unit that predicts a collapse rate of the pattern when the solidified film is sublimated based on the change in concentration over time acquired by the acquisition unit; and an output unit that outputs processing using the prediction result before sublimating the solidified film if the collapse rate predicted by the prediction unit is equal to or greater than a predetermined threshold.

10. The information processing device according to claim 9, wherein the output unit outputs a process using the prediction result by executing a recovery process to prevent the formation of the solidified film.

11. The information processing device according to claim 10, wherein the output section executes the recovery process by further supplying the processing liquid onto the liquid film formed on the main surface.

12. The information processing device according to claim 10, wherein the output section carries out the recovery process by supplying a removal liquid onto the liquid film formed on the main surface to remove the liquid film.

13. An information processing device according to any one of claims 9 to 12, wherein the prediction unit predicts the collapse rate using a trained model that has learned the relationship between the time change in concentration of the sublimable substance and the collapse rate.

14. An information processing device according to any one of claims 9 to 13, wherein the absorbance includes a first absorbance at a first wavelength and a second absorbance at a second wavelength longer than the first wavelength, and wherein the acquisition unit acquires the thickness of the liquid film based on the second absorbance of the liquid film, and acquires the change in concentration over time by calculating the concentration of the sublimable substance based on the first absorbance of the liquid film and the thickness of the liquid film.

15. An information processing device according to claim 14, wherein said first wavelength is in the ultraviolet region and said second wavelength is in the infrared region.

16. An information processing device according to any one of claims 9 to 15, wherein the acquisition unit acquires a spatial distribution of the change in concentration over time on the main surface, and the prediction unit predicts the collapse rate when the solidified film is sublimated based on the spatial distribution of the change in concentration over time acquired by the acquisition unit.

Images