Substrate processing apparatus

Abstract

A substrate processing apparatus includes: a first supply unit that supplies a processing fluid as a gas pressurized to a first pressure lower than a critical pressure to a processing chamber; a second supply unit that supplies a processing fluid having a second pressure higher than the critical pressure; an introduction flow path for introducing a processing fluid into the internal space of the processing chamber; a first pipe that connects the first supply unit and the introduction flow path via a first valve; a second pipe that connects the second supply unit and the introduction flow path via a second valve; and a control unit that controls the first valve and the second valve such that the processing fluid of the first pressure and the processing fluid of the second pressure selectively flow into the internal space. The second supply unit has: a storage unit for storing the liquid processing fluid; and a pressurizing part which is inserted into a second pipe from the storage part to the second valve, pressurizes the processing fluid to a second pressure, and sends the processing fluid out.

Description

TECHNICAL FIELD

[0001] The present application relates to a technology of housing a substrate in a processing chamber to be processed with a processing fluid in a supercritical state. BACKGROUND

[0002] In a processing procedure of various substrates such as semiconductor substrates, glass substrates for display devices, and the like, a procedure of processing a front surface of a substrate with various processing fluids is included. A wet processing using a liquid such as a chemical solution or a cleaning solution as a processing fluid has been widely performed. In recent years, a processing using a processing fluid in a supercritical state has been put into practical use in order to dry a substrate after the wet processing. In particular, in a drying processing of a substrate having a patterned surface in which a fine pattern is formed, a processing with a supercritical processing fluid is advantageous. This is because a processing fluid in a supercritical state has a characteristic of entering a deep portion of a gap of a pattern due to a low surface tension compared to a liquid. By using the processing fluid, a drying processing can be performed with high efficiency. In addition, a risk of pattern collapse due to surface tension at the time of drying can be reduced.

[0003] For example, in a substrate processing apparatus described in Japanese Patent Application Publication No. 2022-132400 (Patent Literature 1), a processing fluid is stored in a tank connected to a circulation line, and the processing fluid is maintained in a liquid state by being circulated in the circulation line in which a condenser is interposed. Further, a connection line branched from the circulation line is connected to a processing chamber, and a processing fluid in a supercritical state is supplied to the processing chamber by heating from a heater provided in the flow path. SUMMARY

[0004] [PROBLEMS TO BE SOLVED BY THE INVENTION]

[0005] In the substrate processing apparatus of the related art as described above, in order to further reduce the risk of pattern collapse, the following problem remains to be solved. That is, according to the present inventor's insight, as described above, in a processing mode in which a processing fluid in a supercritical state is supplied to a processing chamber in which a substrate is housed, a phenomenon that can cause pattern collapse sometimes occurs immediately after the processing fluid is supplied. That is, by the rapid inflow of a processing fluid at a high pressure into a processing chamber at a low pressure of atmospheric pressure or close to atmospheric pressure, a temperature reduction of the processing fluid due to adiabatic expansion occurs. Thereby, the processing fluid sometimes partially phase changes from a supercritical state to a liquid or a solid. In this case, if the liquefied or solidified processing fluid adheres to the substrate, particles can remain on the substrate or pattern collapse can occur.

[0006] In the related art, this problem has not been considered. That is, from the viewpoint of processing a substrate without causing particle adhesion or pattern collapse, it can be said that the related art leaves room for improvement.

[0007] [Technical means for solving the problem]

[0008] The present application has been achieved in view of the above-described problems, and reduces processing failures such as particle adhesion or pattern collapse that can occur due to a temperature decrease when a supercritical processing fluid is introduced into a processing chamber, in a technique of processing a substrate with a supercritical processing fluid.

[0009] One aspect of the present application is a substrate processing apparatus that processes a substrate with a processing fluid in a supercritical state, including: a processing chamber having an internal space that can accommodate the substrate; a first supply section that supplies the processing fluid as a gas pressurized to a first pressure that is lower than a critical pressure; a second supply section that supplies the processing fluid at a second pressure that is higher than the critical pressure; an introduction flow path that communicates with the internal space and introduces the processing fluid into the internal space; a first pipe that connects the first supply section and the introduction flow path via a first valve; a second pipe that connects the second supply section and the introduction flow path via a second valve; and a control section that controls the first valve and the second valve to selectively flow the processing fluid at the first pressure and the processing fluid at the second pressure into the internal space. Here, the second supply section includes: a storage section that stores the processing fluid in a liquid state; and a pressurizing section that is interposed in the second pipe from the storage section to the second valve, pressurizes the processing fluid to the second pressure, and sends it out.

[0010] In the present application thus configured, the processing chamber can be supplied with the processing fluid at the first pressure that is relatively low pressure and the processing fluid at the second pressure that is higher than the first pressure. The processing fluid at the first pressure is supplied to the processing chamber as a gas at a pressure lower than the critical pressure. On the other hand, the second pressure exceeds the critical pressure, and depending on the temperature setting, the processing fluid at the second pressure can be supplied to the processing chamber in a supercritical state.

[0011] If, as in the conventional technique, a processing fluid at a high pressure exceeding the critical pressure is directly introduced into a processing chamber whose internal pressure is substantially atmospheric pressure, there is a concern that processing failures due to partial liquefaction or solidification of the processing fluid will occur. In contrast, in the present application, for example, the internal space of the processing chamber is first filled with the processing fluid from the first supply section, whereby the internal space is preliminarily pressurized to an intermediate first pressure. From this state, the processing fluid in a supercritical state can be introduced. Therefore, the temperature decrease due to adiabatic expansion is more limited, and the problems in the conventional technique can be eliminated.

[0012] [Effects of the invention]

[0013] As described above, according to the present application, the pressure of the internal space of the processing chamber can be raised to an intermediate first pressure prior to the introduction of the processing fluid in the second pressure and supercritical state. By thus introducing the processing fluid in two stages, the sharp temperature drop of the processing fluid due to adiabatic expansion is suppressed. As a result, processing defects such as particle attachment or pattern collapse due to partial liquefaction or solidification of the processing fluid can be prevented.

[0014] The application will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Figure 1 The above and other objects and novel features of the present application will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a diagram showing the schematic configuration of a substrate processing system equipped with an embodiment of the substrate processing apparatus of the present application.

[0016] Figure 2 is a side view showing the entire configuration of the wet processing apparatus.

[0017] Figure 3 is a diagram for explaining the operation of the wet processing apparatus.

[0018] Figure 4 is a side view showing the configuration of the supercritical processing apparatus.

[0019] Figure 5 is a diagram showing the details of the supply and discharge paths of the processing fluid.

[0020] Figure 6 is a flowchart showing the processing performed by the supercritical processing apparatus.

[0021] Figure 7 is a diagram showing the pressure changes in the processing chamber and the reservoir.

[0022] Figure 8 is a diagram showing the open / close states of the valves in the standby operation.

[0023] Figure 9 is a diagram showing the open / close states of the valves at the time of gas introduction.

[0024] Figure 10 is a diagram showing the open / close states of the valves at the time of supercritical processing fluid introduction.

[0025] Figure 11 is a diagram showing the open / close states of the valves at the time of processing fluid replenishment.

[0026] Figure 12 is a diagram showing the state of the processing fluid, i.e., carbon dioxide. DETAILED DESCRIPTION

[0027] Figure 1 FIG. 1 is a diagram showing the schematic configuration of a substrate processing system 1 representing an embodiment of the substrate processing apparatus of the present application. The substrate processing system 1 is, for example, a processing system for supplying a processing liquid to the upper surface of a substrate such as a semiconductor wafer, wet processing the substrate, and then drying the substrate. The substrate processing system 1 has a system configuration suitable for implementing the substrate processing method of the present application. The substrate processing system 1 has, as its main components, a wet processing apparatus 2, a substrate conveyance apparatus 3, a supercritical processing apparatus 4, and a control apparatus 9.

[0028] The wet processing apparatus 2 receives a substrate to be processed and performs a prescribed wet processing. The processing content is not particularly limited. The wet processing includes a development processing or a cleaning processing, etc., but after the development processing or the like is performed, the pattern formation surface of the substrate is in a liquid filled state filled with an organic solvent such as an IPA (Iso-Propyl Alcohol) liquid. The substrate conveyance apparatus 3 conveys the substrate out of the wet processing apparatus 2 while maintaining the liquid filled state and conveys the substrate into the supercritical processing apparatus 4. The supercritical processing apparatus 4 corresponds to the substrate processing apparatus of the present application and performs a drying processing (supercritical drying processing) using a processing fluid in a supercritical state on the substrate conveyed in. These apparatuses are disposed in a clean room. Therefore, the substrate conveyance apparatus 3 conveys the substrate in an atmospheric atmosphere and at an atmospheric pressure.

[0029] The control apparatus 9 controls the operation of the respective apparatuses and realizes a prescribed processing. For the purpose, the control apparatus 9 has a CPU (Central Processing Unit) 91, a memory 92, a storage 93, an interface 94, and the like. The CPU 91 executes various control programs. The memory 92 temporarily stores processing data. The storage 93 stores the control programs executed by the CPU 91. The interface 94 exchanges information with a user or an external apparatus. The operation of the apparatuses described later is realized by the CPU 91 executing the control programs written in advance to the storage 93, causing the respective parts of the apparatuses to perform prescribed operations.

[0030] By the CPU 91 executing prescribed control programs, the control apparatus 9 realizes, in software, functional blocks of a wet processing control section 95 that controls the operation of the wet processing apparatus 2, a conveyance control section 96 that controls the operation of the substrate conveyance apparatus 3, a supercritical processing control section 97 that controls the operation of the supercritical processing apparatus 4, and the like. In addition, at least a part of each of the functional blocks can be configured by a dedicated software.

[0031] As the "substrate" in the present embodiment, various substrates such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for a FED (Field Emission Display), a substrate for an optical disc, a substrate for a magnetic disc, and a substrate for a magneto-optical disc can be applied. Hereinafter, a substrate processing apparatus for processing a disc-shaped semiconductor wafer will be mainly described with reference to the drawings. However, the present embodiment can also be applied to processing of the various substrates exemplified above. In addition, various shapes can be applied to the shape of the substrate.

[0032] In addition, in the following description, a substrate in which a pattern is formed on only one main surface will be exemplified. Here, the main surface on which a pattern or the like is formed will be referred to as the "front surface", and the main surface on the opposite side thereof on which no pattern is formed will be referred to as the "back surface". In addition, the main surface of the substrate facing downward will be referred to as the "lower surface", and the main surface of the substrate facing upward will be referred to as the "upper surface". Hereinafter, the upper surface will be described as the front surface.

[0033] Figure 2 and Figure 3 is a view showing a configuration example of a wet processing apparatus. More specifically, Figure 2 is a side view showing the entire configuration of the wet processing apparatus, Figure 3 is a view for explaining the operation of the wet processing apparatus. The wet processing apparatus 2 is an apparatus that processes a substrate S by supplying a processing liquid to the upper surface of the substrate S. The operation of the wet processing apparatus 2 is controlled by the wet processing control section 95 of the control apparatus 9.

[0034] The wet processing apparatus 2 supplies a processing liquid to the front surface (pattern formation surface) Sa of the substrate S, and performs wet processing such as front surface processing or cleaning of the substrate S. For this purpose, the wet processing apparatus 2 has a substrate holding section 21, a splash guard 22, and processing liquid supply sections 23 and 24 inside a processing chamber 200. These operations are controlled by the wet processing control section 95 provided in the control apparatus 9. The substrate holding section 21 has a circular plate-shaped spin chuck 211 having substantially the same diameter as the substrate S, and a plurality of chuck pins 212 are provided at the peripheral portion of the spin chuck 211. The substrate S is supported by the chuck pins 212 abutting against the peripheral portion of the substrate S, and the spin chuck 211 can hold the substrate S in a horizontal posture in a state in which the upper surface of the substrate S is separated.

[0035] The rotary chuck 211 is supported in a manner that the upper surface thereof becomes horizontal by a rotary support shaft 213 extending downward from the center portion of the lower surface thereof. The rotary support shaft 213 is rotatably supported by a rotary mechanism 214 installed at the bottom of the processing chamber 200. The rotary mechanism 214 has a rotary motor not shown therein. The rotary chuck 211 directly coupled to the rotary support shaft 213 is rotated about the rotary axis AX shown by a one-dot chain line by the rotation of the rotary motor according to a control command from the control device 9. Figure 2 The substrate S is rotated about the rotary axis AX in a horizontal posture.

[0036] A splash guard 22 is provided in a manner that the substrate holding portion 21 is surrounded from the side. The splash guard 22 has a substantially cylindrical cup 221 provided in a manner that the peripheral portion of the rotary chuck 211 is covered, and a liquid receiving portion 222 provided at the lower portion of the outer peripheral portion of the cup 221. The cup 221 is raised and lowered according to a control command from the control device 9. The cup 221 is moved up and down between a lower position shown in Figure 2 and an upper position shown in Figure 3 The lower position is a position where the upper end portion of the cup 221 is lowered below the peripheral portion of the substrate S held on the rotary chuck 211. The upper position is a position where the upper end portion of the cup 221 is positioned above the peripheral portion of the substrate S.

[0037] When the cup 221 is positioned at the lower position, the substrate S held on the rotary chuck 211 is exposed to the outside of the cup 221 as shown in Figure 2 Therefore, for example, the cup 221 does not become an obstacle when the substrate S is carried into and out of the rotary chuck 211.

[0038] When the cup 221 is positioned at the upper position, the peripheral portion of the substrate S held on the rotary chuck 211 is surrounded as shown in Figure 3 Therefore, the processing liquid splashed from the peripheral portion of the substrate S is prevented from flying into the chamber 200, and the processing liquid can be surely recovered. That is, the droplets of the processing liquid splashed from the peripheral portion of the substrate S by the rotation of the substrate S adhere to the inner wall of the cup 221, and flow downward to be collected and recovered by the liquid receiving portion 222 provided at the lower portion of the cup 221. In order to individually recover a plurality of processing liquids, a plurality of cups can be concentrically provided.

[0039] The processing liquid supply portion 23 has a configuration in which a rotary support shaft 232 is rotatably provided with respect to a base 231 fixed to the processing chamber 200, and a nozzle 234 is installed at the front end of an arm 233 extending horizontally from the rotary support shaft 232. The arm 233 is swung by the rotation of the rotary support shaft 232 according to a control command from the control device 9. Therefore, the nozzle 234 at the front end of the arm 233 is retracted from the upper direction of the substrate S to a retracted position shown in Figure 2 and is projected to a projection position shown inFigure 3 moves between the processing positions above the substrate S.

[0040] The nozzle 234 is connected to a processing liquid supply source 238, and when an appropriate processing liquid is sent from the processing liquid supply source 238, the processing liquid is sprayed from the nozzle 234 toward the substrate S. As shown in Figure 3 As shown, the substrate S is rotated by the spin chuck 211 rotating at a relatively low speed, and the processing liquid Ll is supplied from the nozzle 234 positioned above the center of rotation of the substrate S. In this way, the front surface Sa of the substrate S is processed by the processing liquid Ll. As the processing liquid Ll, a liquid having various functions such as a developing liquid, an etching liquid, a cleaning liquid, a rinsing liquid, and the like can be used, and the composition thereof is arbitrary. Furthermore, processing can be performed by combining a plurality of processing liquids.

[0041] The other set of processing liquid supply sections 24 also has a configuration corresponding to the first processing liquid supply section 23. That is, the second processing liquid supply section 24 has a base 241, a rotating shaft 242, an arm 243, and a nozzle 244, and the like. The configurations of these are the same as the corresponding configurations in the first processing liquid supply section 23. The arm 243 swings by the rotating shaft 242 rotating in accordance with a control command from the control device 9. The nozzle 244 at the front end of the arm 243 supplies a processing liquid to the front surface Sa of the substrate S.

[0042] In the embodiment, the second processing liquid supply section 24 is used for the purpose of forming a liquid film for preventing drying on the substrate S after wet processing. That is, the substrate S after wet processing is carried to the supercritical processing device 4, and subjected to supercritical drying processing. At this time, in order to prevent the front surface of the substrate S from being oxidized or a fine pattern formed on the front surface from collapsing during the carrying, the substrate S is carried in a state in which the front surface is covered with a paddle-shaped liquid film.

[0043] As the liquid constituting the liquid film, a main component of a processing liquid used for cleaning processing, that is, a substance having a surface tension smaller than water, such as an organic solvent such as isopropyl alcohol (IPA) or acetone, is used. These organic solvents are supplied from an organic solvent supply source 248.

[0044] Here, two sets of processing liquid supply sections are provided in the wet processing device 2, but the number of sets of processing liquid supply sections or the configuration and function thereof are not limited to this. For example, the processing liquid supply sections can be only one set, and furthermore, three or more sets can be provided. Furthermore, one processing liquid supply section can have a plurality of nozzles. For example, a plurality of nozzles can be provided at the front end of one arm. Furthermore, not only aspects in which the nozzles as described above spray a processing liquid in a state in which they are positioned at a prescribed position, but also aspects in which, for example, the nozzles spray a processing liquid while scanning and moving along the front surface Sa of the substrate S can be included.

[0045] Returning to Figure 1Continuing the explanation. The substrate conveying device 3 is provided with a conveying robot 30 in which a hand 31 is provided at the tip of an arm that is capable of extending and retracting and rotating freely. The hand 31 is capable of supporting a substrate by coming into contact with the lower surface portion of the substrate, as shown in Figure 1 The substrate conveying robot 30 is capable of moving in and out with respect to the wet processing device 2 and the supercritical processing device 4, as shown by the dotted line. Thus, the substrate can be conveyed in and out of each of the wet processing device 2 and the supercritical processing device 4. The operation of the substrate conveying robot 30 is controlled by the conveying control section 96 of the control device 9. There are many known technologies for such a substrate conveying robot, and since these technologies can be appropriately selected for use in the present embodiment, a detailed explanation will be omitted.

[0046] Figure 4 is a side view showing the configuration of the supercritical processing device. The supercritical processing device 4 corresponds to the first embodiment of the substrate processing device of the present application, and is a device that performs drying processing on a substrate S after wet processing using a processing fluid in a supercritical state. More specifically, the supercritical processing device 4 is a device that receives a substrate S after wet processing, replaces the liquid remaining on the substrate S with a processing fluid in a supercritical state, and then discharges the processing fluid, thereby bringing the substrate S to a final dry state.

[0047] The supercritical processing device 4 is provided with a processing unit 41, a transfer unit 43, and a supply unit 45. The processing unit 41 is the main body that performs supercritical drying processing. The transfer unit 43 receives a substrate S after wet processing that is conveyed by the substrate conveying device 3, and conveys it into the processing unit 41. In addition, the processed substrate S is handed over from the processing unit 41 to an external conveying device. The supply unit 45 supplies chemicals, power, and energy, etc. required for processing to the processing unit 41 and the transfer unit 43. These operations are controlled by the control device 9, particularly the supercritical processing control section 97.

[0048] The processing unit 41 has a configuration in which a processing chamber 412 is mounted on a pedestal 411. The processing chamber 412 is composed of a combination of several metal blocks, and has an internal cavity that constitutes a processing space SP. A substrate S that is the object of processing is conveyed into the processing space SP, and receives processing. On the (-Y) side surface of the processing chamber 412, a slit-shaped opening 421 is formed that extends long in the X direction. The processing space SP communicates with the outside space via the opening 421. The cross-sectional shape of the processing space SP is substantially the same as the opening shape of the opening 421. That is, the processing space SP is a cavity that extends in the Y direction, and has a cross-sectional shape that is longer in the X direction and shorter in the Z direction.

[0049] On the (-Y) side of the processing chamber 412, a lid member 413 is provided so as to occlude the opening 421. By occluding the opening 421 of the processing chamber 412 with the lid member 413, a gas-tight processing container is constituted. Thus, processing of the substrate S at high pressure can be performed in the internal processing space SP. On the (+Y) side of the lid member 413, a flat plate-shaped support tray 415 is installed in a horizontal posture. The upper surface of the support tray 415 becomes a support surface on which the substrate S can be placed. The lid member 413 is supported so as to be movable in the Y direction by a support mechanism, which is not shown.

[0050] The lid member 413 is movable in and out with respect to the processing chamber 412 by a feed and withdrawal mechanism 453 provided in the supply unit 45. Specifically, the feed and withdrawal mechanism 453 has, for example, a linear motor, a direct-acting guide, a ball screw mechanism, a solenoid, or a cylinder, or the like direct-acting mechanism. This direct-acting mechanism moves the lid member 413 in the Y direction. The feed and withdrawal mechanism 453 is actuated in accordance with a control command from the control device 9.

[0051] The lid member 413 is moved in the (-Y) direction to be away from the processing chamber 412. As shown by the broken line, when the support tray 415 is pulled out to the outside from the processing space SP via the opening 421, the support tray 415 can be accessed. That is, the placement of the substrate S on the support tray 415 and the extraction of the substrate S placed on the support tray 415 can be performed. On the other hand, by moving the lid member 413 in the (+Y) direction, the support tray 415 is housed in the processing space SP. In the case where the substrate S is placed on the support tray 415, the substrate S is carried into the processing space SP together with the support tray 415.

[0052] By moving the lid member 413 in the (+Y) direction, the opening 421 is covered and the processing space SP is sealed. Between the (+Y) side of the lid member 413 and the (-Y) side of the processing chamber 412, a seal member 422 is provided to maintain the gas-tight state of the processing space SP. The seal member 422 is made of rubber, for example. Further, the lid member 413 is fixed with respect to the processing chamber 412 by a locking mechanism, which is not shown. In this way, in the present embodiment, the lid member 413 is switched between a state of occluding the opening 421 to seal the processing space SP (solid line) and a state of being largely separated from the opening 421 so that the substrate S can be accessed (broken line).

[0053] In a state in which the airtightness of the processing space SP is ensured, processing of the substrate S is performed in the processing space SP. In the present embodiment, the fluid supply unit 45 supplies, as the processing fluid, a substance that can be used for supercritical processing, such as carbon dioxide, to the processing chamber 412. Further, the processing fluid is brought to a supercritical state by being pressurized in the processing chamber 412. The processing fluid is supplied to the processing unit 41 in a gaseous or liquid state. Carbon dioxide becomes a supercritical state at a relatively low temperature and low pressure, and, in addition, has the property of dissolving an organic solvent that is often used for substrate processing, and thus is a chemical substance that is suitable for supercritical drying processing. The critical point at which carbon dioxide becomes a supercritical state is a gas pressure (critical pressure) of 7.38 MPa and a temperature (critical temperature) of 31.1°C.

[0054] When the processing space SP is filled with the processing fluid, and the processing space SP reaches an appropriate temperature and pressure, the processing space SP is filled with the processing fluid in a supercritical state. Thus, the substrate S is processed in the processing chamber 412 with the processing fluid in a supercritical state. The fluid supply unit 45 is provided with a fluid recovery unit 455, and the processed fluid is recovered by the fluid recovery unit 455. The fluid supply unit 457 and the fluid recovery unit 455 are controlled by the supercritical processing control unit 97.

[0055] The processing space SP has a shape and a volume that can receive the support tray 415 and the substrate S supported on the support tray 415. That is, the processing space SP has a substantially rectangular cross-sectional shape that is wider than the width of the support tray 415 in the horizontal direction, and is greater than the total height of the support tray 415 and the substrate S in the vertical direction, and a depth that can receive the support tray 415. Thus, the processing space SP has a shape and a volume that receive only the support tray 415 and the substrate S. However, the gap between the support tray 415 and the substrate S and the inner wall surface of the processing space SP is small. Therefore, the amount of processing fluid required to fill the processing space SP is relatively small.

[0056] The fluid supply unit 457 supplies the processing fluid to the processing space SP further on the (+Y) side than the (+Y) side end portion of the substrate S. On the other hand, the fluid recovery unit 455 discharges the processing fluid that flows through the space above the substrate S and the space below the support tray 415 in the processing space SP further on the (-Y) side than the (-Y) side end portion of the substrate S. Thus, in the processing space SP, a laminar flow of the processing fluid is formed from the (+Y) side toward the (-Y) side in each of the space above the substrate S and the space below the support tray 415.

[0057] The supercritical processing control section 97 of the control device 9 specifies the pressure and temperature in the processing space SP based on the detection results of a detection section not shown, and controls the fluid supply section 457 and the fluid recovery section 455 based on the results thereof. Thus, the supply of the processing fluid to the processing space SP and the discharge of the processing fluid from the processing space SP are appropriately managed. The pressure and temperature in the processing space SP are adjusted according to a processing recipe determined in advance.

[0058] The transfer unit 43 takes over the substrate S between the substrate conveyance device 3 and the support tray 415. For this purpose, the transfer unit 43 is provided with a body 431, a lifting member 433, a base member 435, and a plurality of lift pins 437. The lifting member 433 is a columnar member extending in the Z direction, and is movably supported in the Z direction with respect to the body 431 by a support mechanism not shown. On the upper portion of the lifting member 433, the base member 435 having a substantially horizontal upper surface is mounted. The plurality of lift pins 437 are erected upward from the upper surface of the base member 435. The lift pins 437 each support the substrate S in a horizontal posture from below by abutting the lower surface of the substrate S with the upper end portion thereof. In order to stably support the substrate S in the horizontal posture, it is desirable to provide three or more lift pins 437 whose upper end portions are equal in height to each other.

[0059] The lifting member 433 is movable up and down by a lifting mechanism 451 provided in the supply unit 45. Specifically, the lifting mechanism 451 has, for example, a linear motor, a direct-acting guide, a ball screw mechanism, a solenoid, or a cylinder, or the like. Such a direct-acting mechanism moves the lifting member 433 in the Z direction. The lifting mechanism 451 operates according to a control command from the control device 9.

[0060] By the up-and-down movement of the lifting member 433, the base member 435 moves up and down, and the plurality of lift pins 437 move up and down integrally therewith. Thus, the transfer of the substrate S between the transfer unit 43 and the support tray 415 is achieved. More specifically, as shown by a broken line in FIG. 6, the substrate S is transferred while the support tray 415 is pulled out to the outside of the chamber. For this purpose, the support tray 415 is provided with through-holes 419 through which the lift pins 437 are inserted. When the base member 435 is raised, the upper end portions of the lift pins 437 reach above the upper surface of the support tray 415 through the through-holes 419. In this state, the substrate S conveyed by the conveyance robot 30 is transferred from the hand 31 of the conveyance robot 30 to the lift pins 437. By lowering the lift pins 437, the substrate S is transferred from the lift pins 437 to the support tray 415. The conveyance of the substrate S out can be performed in the reverse order. Figure 4

[0061] ​Next, the supply path of the processing fluid to the processing chamber 412 and the discharge path of the processing fluid from the processing chamber 412 will be described in more detail. Above, the supply of processing fluid from the fluid supply unit 457 to the processing chamber 412 and the recovery of processing fluid from the processing chamber 412 to the fluid recovery unit 455 were briefly described. In the actual device, the fluid supply unit 457 and the fluid recovery unit 455 have the following configuration.

[0062] Figure 5 It is a diagram showing the details of the supply and discharge paths for the processed fluid. Additionally, Figure 5 In the diagram, for ease of illustration, the orientation of the processing chamber 412 is shown in the figure. Figure 4 On the contrary, that is to say, Figure 4 In the middle, the processing fluid is introduced into the processing chamber 412 from the right side of the paper and discharged to the left side of the paper. On the other hand, Figure 5 Conversely, the flow becomes one where the processing fluid is introduced into the processing chamber 412 from the left side of the paper and discharged to the right side of the paper. That is to say, Figure 5 In the processing chamber 412, a diagram showing the relationship with... Figure 4 The processing chamber 412 is on the opposite side.

[0063] First, the detailed structure of the fluid supply unit 457 will be described. The fluid supply unit 457 mainly consists of a fluid supply source 700, a purification unit 710, a supply unit 720, and piping groups 730 and 740 connecting these. These operate according to control commands from the supercritical processing control unit 97.

[0064] The fluid supply source 700 outputs the substance used as a processing fluid in the supercritical process (carbon dioxide in this embodiment) as needed. The fluid supply source 700 may also be provided as part of the substrate processing system 1 and may be constituted by a container for storing the substance, such as a high-pressure gas cylinder. Alternatively, it may be an external supply source separately provided with the substrate processing system 1.

[0065] At the fluid supply source 700, a portion of the piping group 730, namely piping 731, is connected. The processed fluid delivered from the fluid supply source 700... Figure 5 The fluid flows through piping 731 from center to right. In piping 731, along the flow direction of the processed fluid, valves V70 and V71, purifier 711, filter 712, condenser 713, and valve V72 are sequentially arranged. Valve V70 is, for example, a pressure regulating valve that functions to adjust the pressure of the processed fluid flowing through piping 731. The other valves, V71 and V72, are on / off valves that switch the flow of fluid.

[0066] The valve V70 causes the treatment fluid at a pressure specified in accordance with a control command from the supercritical treatment control section 97 to flow in the pipe 731. The purifier 711 and the filter 712 remove impurities contained in the treatment fluid, and increase the purity. The condenser 713 condenses the treatment fluid sent out as a gas from the fluid supply source 700. When the valves V71 and V72 are opened, the treatment fluid is output from the pipe 731.

[0067] The pipe 731 merges with the pipe 735 connected to the tank 717 described later on the output side of the valve V72. In the pipe 732 after the merging, the condenser 714, the pressurizing pump 715, and the filter 716 are provided. The condenser 714 is provided to more surely maintain the treatment fluid in a liquid phase. The pressurizing pump 715 pressurizes and sends out the treatment fluid in a liquid state. The filter 716 removes impurities from the treatment fluid.

[0068] The pipe 732 branches into two pipes 733 and 734 on the output side of the filter 716. The pipe 733 is connected to the upper portion of the tank 717, and an on-off valve, that is, the valve V74 is interposed in the middle of the way. Further, the on-off valve, that is, the valve V75 is interposed in the pipe 734.

[0069] The tank 717 is a high-pressure container having a function of storing the treatment fluid pressurized in a liquid state. A liquid level sensor 718 is provided in the tank 717, and the height of the liquid surface is managed. Therefore, the inside space of the tank 717 does not become a liquid-tight state, and the treatment fluid gasified is stored in a state pressurized to the same degree as the liquid in the space above the liquid surface. Further, a heater 719 is installed in the tank 717, and the heater 719 can heat the treatment fluid in the tank in accordance with a control command from the supercritical treatment control section 97.

[0070] The pipe 735 is connected to the lower portion of the tank 717, and merges with the pipe 731, and is connected to the pipe 732. When the on-off valve, that is, the valve V73 interposed in the pipe 735 is opened, the liquid of the treatment fluid in the tank 717 flows into the pipe 732 via the pipe 735. If the valve V74 on the pipe 733 is further opened, a reflux flow path from the tank 717 through the pipes 735, 732, and 733 to the tank 717 is formed. If the treatment fluid is pressurized by the pressurizing pump 715 while circulating the treatment fluid in the reflux path, the pressure of the treatment fluid can be increased in stages. Finally, the treatment fluid is stored in the tank 717 in a state increased to a pressure specified in accordance with a control command from the supercritical treatment control section 97.

[0071] An output pipe 736 is connected to the upper part of the storage tank 717. Pipe 736 merges with pipe 734 via an on / off valve, namely valve V76. Processing fluid that fills the upper part of the internal space of the storage tank 717 is output from pipe 736. After merging with pipes 734 and 736, pipe 741 selectively receives either the gaseous processing fluid when valve V76 is open or the liquid processing fluid when valve V75 is open.

[0072] Thus, the refining unit 710 of the fluid supply section 457 has the following function: after removing impurities from the processing fluid supplied by the fluid supply source 700, it selectively outputs the phase required for subsequent processing, specifically, the gas phase and the liquid phase of the processing fluid.

[0073] Pipe 741 is part of a piping group 740 that forms the inlet flow path for introducing the processed fluid from the refining unit 710 to the processing chamber 412. Pipe 741 branches into two pipes 743 and 744 downstream of the on / off valve, namely valve V77, and filters 721 and 722 are installed on each pipe. These pipes 743 and 744 temporarily merge to form pipe 745, which further branches into two pipes 747 and 748.

[0074] In piping 747, along the flow direction of the processed fluid (to the right in the figure), a flow meter 723, a heater 725, an on / off valve (valve V78), and a filter 727 are sequentially inserted. Piping 747 is finally connected to the processing chamber 412. More specifically, piping 747 is located on the support tray 415 of the support substrate S (… Figure 4 Above, it communicates with the internal space SP. On the other hand, along the flow direction of the processed fluid, a flow meter 724, a heater 726, an on / off valve (valve V79), and a filter 728 are sequentially inserted in the piping 748. Furthermore, the piping 748 is located above the support tray 415 of the support substrate S. Figure 4 Below, it communicates with the internal space SP of the processing chamber 412. Thus, processing fluid is supplied to the spaces above and below each of the substrate S placed on the support tray 415 in the internal space SP.

[0075] Flow meters 723 and 724 measure the flow rate of the processed fluid at various locations and send the results to the supercritical processing control unit 97. Heaters 725 and 726 heat the processed fluid to a specified temperature according to control commands from the supercritical processing control unit 97. Filters 727 and 728 ultimately remove impurities from the processed fluid introduced into the processing chamber 412.

[0076] Thus, the fluid supply unit 457 can supply the processing chamber 412 with purified processing fluid, the temperature of which is adjusted to a predetermined target value. The sequence of supplying the processing fluid from the fluid supply unit 457 to the processing chamber 412 will be described in detail below.

[0077] The processing fluid supplied to the processing chamber 412 is sent from the tank 717, and the processing fluid pressurized by the pressurizing pump 715 is stored in the tank 717. Therefore, the pressure of the processing fluid sent from the fluid supply source 700 can also be lower than the pressure required for processing. In addition, in the case where the fluid supply source 700 is capable of stably sending the processing fluid at a pressure suitable for processing, as shown by a dashed line, the processing fluid in the gaseous phase can also be supplied directly from the fluid supply source 700 via the pipe 737 without being taken from the tank 717. Furthermore, the processing fluid after pressure adjustment can also be supplied from the output side of the valve V70. Figure 5

[0078] Next, the detailed configuration of the fluid recovery section 455 will be described. The fluid recovery section 455 is provided with the high-pressure exhaust tank 505, the low-pressure exhaust tank 508, and the pipe group 530 connecting these exhaust tanks, as the main components. These act in accordance with the control instructions from the supercritical processing control section 97.

[0079] In the upper portion of the processing chamber 412, the pipe 531, which is a part of the pipe group 530, is connected. On the other hand, the pipe 532 is connected in the lower portion of the processing chamber 412. These pipes 531, 532 respectively exhaust the processing fluid flowing above and below the support tray 415 in the internal space SP from the processing chamber 412 to the outside. The pressure gauge 503 is provided in the pipe 531.

[0080] In the pipe 531, along the flow direction of the processing fluid, the flowmeter 501 and the on-off valve, that is, the valve V51, are sequentially interposed. On the other hand, in the pipe 532, along the flow direction of the processing fluid, the flowmeter 502 and the on-off valve, that is, the valve V52, are sequentially interposed. In the output sides of the valves V51, V52, the pipes 531, 532 are merged. In the merged pipe 533, the pressure regulating valve, that is, the valve V53, and the on-off valve, that is, the valve V54, are interposed.

[0081] The pipe 533 is connected to the high-pressure exhaust tank 505, and the processing fluid exhausted from the processing chamber 412 is stored in the high-pressure exhaust tank 505 via the pipe 533. The heater 506 is provided in the high-pressure exhaust tank 505, and the temperature of the processing fluid stored in the inside is appropriately maintained.

[0082] ​A pipe 544 is connected to the upper portion of the high-pressure exhaust tank 505, and a valve V55, a pressure regulator valve V56, and a heater 507 are interposed in the pipe 544, which is finally connected to a low-pressure exhaust tank 508. Thus, the processing fluid, which is a gas after appropriate adjustment of the pressure and temperature, flows into the low-pressure exhaust tank 508. The processing fluid in the low-pressure exhaust tank 508 is finally recovered by an external recovery device, not shown, via a pipe 545. In the pipe 545, a heater 509 for adjusting the temperature of the gas to be discharged to the outside and a pressure gauge 510 for detecting the pressure of the gas are provided.

[0083] Further, a pipe 546 is connected to the lower portion of the high-pressure exhaust tank 505, and a pipe 547 is connected to the lower portion of the low-pressure exhaust tank 508. These pipes are combined to become a pipe 548, and a valve V57 is connected to the pipe 548. When the valve V57 is opened, the processing fluid, which is the liquid stored in the high-pressure exhaust tank 505 and the low-pressure exhaust tank 508, is discharged to the external recovery device.

[0084] Reference Figure 6 and Figure 7 The operation of the supercritical processing device 4 configured as described above will be described. The supercritical processing device 4 performs a process of bringing the substrate S after wet processing to a dry state using a processing fluid in a supercritical state, that is, a supercritical dry processing. The process is realized by controlling the components of the control device 9 by executing a control program prepared in advance by the CPU 91 of the control device.

[0085] Figure 6 is a flowchart showing the process performed by the supercritical processing device. Further, Figure 7 is a graph showing the change in the pressure in the processing chamber and the tank during the process. The fluid supply section 457 supplies the processing fluid of the gas and the liquid from the tank 717 storing the processing fluid to the processing chamber 412. Thus, the pressure in the processing space SP of the processing chamber 412 (hereinafter referred to as "chamber internal pressure") and the pressure in the internal space of the tank 717 (hereinafter referred to as "tank internal pressure") change as the process progresses.

[0086] First, the substrate carrying device 3 cooperates with the supercritical processing device 4 to carry the substrate S into the processing chamber 412 (step S101). Specifically, the carrying robot 30 of the substrate carrying device 3 holds the substrate S on which the liquid film formation process in the wet processing device 2 has been completed, and places the substrate S on the support tray 415 in a state pulled out from the processing chamber 412. More specifically, first, the substrate S is handed over from the hand 31 of the carrying robot 30 to the lift pins 437 of the supercritical processing device 4, and then the substrate S is handed over from the lift pins 437 to the support tray 415.

[0087] The support tray 415 on which the substrate S is placed is housed in the processing chamber 412. The processing space SP inside the processing chamber 412 is sealed by closing the opening 421 of the processing chamber 412 with the lid member 413. Thus, the loading of the substrate S is completed. Since the processing chamber 412 is opened to the atmosphere in order to load the substrate S, as Figure 7 As shown in the upper stage, the internal pressure of the processing chamber 412 is atmospheric pressure Pa in the initial state.

[0088] Thus, during the handover of the substrate S, a prescribed standby operation is performed in the fluid supply section 457 (step S102). Details of the standby operation are described later, but the standby operation is an operation in the fluid supply section 457 for preparing an appropriate amount of processing fluid at a temperature and pressure suitable for use in the subsequent processing. As described later, in the embodiment, carbon dioxide in a gaseous state at a temperature of 20°C and a pressure of 6 MPa, and carbon dioxide supercriticalized by heating from a temperature of 20°C and a pressure of 11 MPa are used for processing.

[0089] After the substrate S is loaded, the introduction of the processing fluid in a gaseous phase from the fluid supply section 457 is started (step S103; time Tl), whereby the internal pressure of the chamber gradually increases. When the internal pressure of the chamber increases to a predetermined first pressure Pl (step S104; time T2), the processing fluid in a supercritical state is supplied from the fluid supply section 457 to the processing chamber 412 in place of the gas (step S105; time T3).

[0090] Thus, the processing space SP of the processing chamber 412 is filled with the processing fluid in a supercritical state, and the internal pressure of the chamber is maintained at the first pressure Pl and a certain second pressure P2 that is greater than the critical pressure of the processing fluid (times T4 to T5). During this period, the liquid adhering to the substrate S is replaced by the supercritical processing fluid and dissolved in the processing fluid, and is removed from the front surface of the substrate S.

[0091] When the internal pressure of the chamber is maintained at substantially the pressure P2 for a prescribed period of time (step S106), the processing fluid is discharged from the processing chamber 412 (step S107; time T5), whereby the processing space SP is depressurized. After the internal pressure of the chamber decreases to the vicinity of the atmospheric pressure Pa at time T7, the substrate S is unloaded by the transfer robot 30 (step S108), and the processing of one piece of the substrate S is completed. Then, when there is a substrate to be processed, the processing returns to step S101 (step S109), and the processing is repeated.

[0092] As Figure 7 As shown in the lower stage, the internal pressure of the tank gradually decreases by consuming the processing fluid stored in the tank 717. In order to restore it and supplement the processing fluid to the tank 717, a standby operation is performed (step S111). The standby operation can be performed after the time T6 at which the supply of the processing fluid from the tank 717 to the processing chamber 412 is stopped. Thus, asFigure 7 As shown, during the pressure reduction in the processing chamber 412, the standby operation can be started.

[0093] When performing the supercritical drying process of the substrate S, it is desirable to raise the tank pressure to a pressure that is the same as or slightly higher than the first pressure P1 in the standby operation in order to raise the pressure in the chamber to the first pressure P1 in the step S103 of the process.

[0094] Figures 8 to 11 The figures show the state of the valves in each stage of the process. In these figures, the flow of the process fluid that flows as a gas on the flow path is indicated by a thick dotted arrow, and the flow of the process fluid that flows as a liquid is indicated by a thick solid arrow. In addition, in particular Figure 10 In the supercritical state, the flow of the process fluid is indicated by a hollow arrow.

[0095] In addition, in these figures, the open / close valves, that is, the valves in which a white circle (O) is marked near the figure symbol and a single underscore is marked on the symbol, indicate that the valve is open. On the other hand, the valves in which a black circle (·) is marked near the figure symbol and a double underscore is marked on the symbol indicate that the valve is closed. The valves that are not marked in this way are valves that do not directly affect the process described below, and thus, the open / close state thereof is not particularly limited here.

[0096] Figure 8 The open / close state of the valves in the standby operation is shown. In the standby operation, the process fluid output from the fluid supply source 700 is pressurized by the pressurizing pump 715 and is caused to flow into the storage tank 717. Thus, the tank pressure is raised to a target value. For this purpose, as shown in the figure, Figure 8 The valves V71, V72, and V74 are opened, and on the other hand, the valves V73, V75, and V76 are closed.

[0097] Thus, the process fluid that is output from the fluid supply source 700 and whose pressure is adjusted by the valve V70 is accumulated in the storage tank 717 as a liquid that is pressurized to a prescribed pressure by the pressurizing pump 715. The amount of liquid in the tank is monitored by the liquid level sensor 718. The supply of the process fluid is continued until a liquid of a predetermined pressure is accumulated to a predetermined amount. In addition, the temperature of the process fluid in the tank is adjusted by the heater 719.

[0098] Thus, during the standby period in which the supply of the process fluid from the storage tank 717 to the processing chamber 412 is not performed Figure 7before time Tl and after time T6), a process for maintaining the amount of liquid, pressure, and temperature in the tank at a predetermined value is executed as standby operation. The target value of the pressure is the first pressure PI or a pressure slightly higher than the first pressure PI, and in this embodiment, 6 MPa. Further, the target temperature is 20°C in this embodiment. Further, the target value of the amount of liquid is set to an amount that can sufficiently supply the processing chamber 412 with the processing fluid in the supercritical drying process.

[0099] Figure 9 The opening and closing states of the valves at the time of gas introduction are shown. In step S103 (time Tl to T2), the processing chamber 412 is introduced with the processing fluid in a gaseous state, and the pressure in the chamber is increased. In the pressure increasing stage, the valves V72, V74, and the like on the path for supplying the tank 717 with the processing fluid are closed, and the supply path is cut off, whereas the valves V76 on the pipe 736 connected to the upper portion of the tank and the valves V77 to V79 provided in the pipe group 740 and the like are opened. Thus, the gas filled in the inside of the tank 717 above the liquid surface is supplied to the processing chamber 412 through the pipe group 740.

[0100] Thus, Figure 7 The chamber pressure shown in the upper stage is increased from the atmospheric pressure Pa to the first pressure PI. At this time, Figure 7 The tank pressure shown in the lower stage is decreased from time Tl at which the processing fluid starts to be output. However, the decrease in the tank pressure gradually becomes slow by the operation of the heater 719 in a manner to compensate for the decrease in the temperature in the tank due to the sharp decrease in the pressure.

[0101] On the other hand, in the fluid recovery section 455, the valves V51 to V57 provided in the pipe group 530 are opened, and an exhaust flow path of the processing fluid is formed. Thus, in the pressure increasing stage, a certain amount of the processing fluid is also exhausted. Thus, the atmosphere or liquid, impurities, and the like remaining in the processing chamber 412 are also exhausted to the outside of the chamber.

[0102] Further, as for the chamber pressure, it can be indirectly measured by the pressure gauge 503 provided in the pipe 531 on the exhaust flow path communicating with the processing space SP. Thus, in step S106, the measurement result of the pressure gauge 503 can be used to make a determination of the chamber pressure. However, if the correlation between the amount of the processing fluid supplied to the processing chamber 412 and the chamber pressure is obtained in advance, the time until the chamber pressure reaches the target value can be predicted. Thus, in the actual apparatus, by determining in advance the length of the period during which the valve V76 that governs the gas supply is opened, the actual measurement of the chamber pressure can be omitted. That is, as explained above, in step S106, a determination based on the elapsed time can be adopted.

[0103] Figure 10The open / close state of the valve at the time of introduction of the supercritical processing fluid is shown. In step S105 (time T3 to T5), the processing chamber 412 is supplied with the processing fluid in a supercritical state. Therefore, it is necessary to make the temperature of the processing fluid to be supplied higher than the critical temperature and the pressure higher than the critical pressure, respectively. Therefore, by closing the valve V76 to stop the supply of the gas, the valves V73 and V75 are opened instead, whereby the liquid of the processing fluid stored in the tank 717 is supplied to the processing chamber 412.

[0104] The flow path of the processing fluid at this time is provided with the pressurizing pump 715, and the processing fluid is supplied in the pipe group 740 in a state in which the pressure is increased to a pressure (the second pressure P2 in this embodiment) exceeding the critical pressure. The processing fluid is heated to a temperature above the critical temperature by the heaters 725 and 726 provided in the flow path, and the processing fluid flows into the processing chamber 412 in a supercritical state. In this way, the processing space SP is filled with the processing fluid in a supercritical state.

[0105] In this case, the discharge flow path for discharging a small amount of the processing fluid from the processing chamber 412 is opened. Therefore, by the processing fluid replacement and the liquid or the like separated from the substrate S is discharged to the outside together with the processing fluid, reattachment to the substrate S is prevented. The tank pressure is sharply decreased as the liquid starts to be supplied, but the degree of decrease in the pressure is made small by heating by the heater 719.

[0106] At time T5, the flow rate of the processing fluid output from the pressurizing pump 715 is decreased, and thus the pressure in the chamber starts to decrease. In order to prevent the processing fluid from being liquefied or solidified due to a sharp decrease in pressure, causing damage to the substrate S, the speed of decrease in pressure is adjusted in such a manner that the processing fluid directly changes from a supercritical state to a gas phase. If the pressure in the chamber is sufficiently decreased (for example, to below the critical pressure), the risk of liquefaction and solidification disappears, and then the supply of the processing fluid to the processing chamber 412 is stopped, and the discharge flow rate is increased to discharge the remaining processing fluid. Thus, rapid decrease in pressure can be performed.

[0107] For example, a method such as from Figure 10 The state shown in FIG. 8 is changed in the order of closing the valve V75 at time T6 and opening the valve V74 instead. Then, the processing fluid supplied from the pressurizing pump 715 is returned to the tank 717, and thus the decrease in the pressure in the tank is suppressed. In addition, after the supply of the processing fluid to the processing chamber 412 is stopped, the processing fluid can be replenished from the fluid supply source 700 to the tank 717.

[0108] Figure 11The open / close state of the valve at the time of processing fluid replenishment is shown. In the fluid recovery section 455, even during the pressure reduction process, it is possible to restart the sending of the processing fluid from the fluid supply source 700 after stopping the supply of the processing fluid to the processing chamber 412, that is, after the time T6 when the valve V75 is closed. Thus, it is possible to supply the processing fluid to the reservoir 717 via the pressurizing pump 715. Thus, it is possible to recover the tank pressure and the liquid amount, ready for processing of the next substrate.

[0109] The operation of the fluid supply section 457 at this time is as compared Figure 8 with Figure 11 It is understood that the same as the standby operation. That is, it is possible to perform the standby operation of the fluid supply section 457 simultaneously with the pressure reduction operation in the fluid recovery section 455 and the subsequent processing such as the unloading of the substrate S by the transfer robot 31. Therefore, after the unloading of the processed substrate, it is possible to quickly receive a new substrate and perform processing.

[0110] As described above, in the supercritical drying process of the present embodiment, first, carbon dioxide as a gas (20°C, 6 MPa) is introduced as the processing fluid to the processing chamber 412 to increase the pressure of the processing space SP. Subsequently, carbon dioxide as a liquid (20°C, 11 MPa) is heated to be supercritical and introduced to the processing chamber 412. The reason for thus supplying the processing fluid in two stages will be described below.

[0111] Figure 12 is a state diagram of the processing fluid, that is, carbon dioxide. In the diagram, point C indicates the critical point of carbon dioxide, and the critical pressure Pc of carbon dioxide is 7.38 MPa and the critical temperature Tc is 31.1°C. The state of the processing fluid introduced in the initial stage of the supercritical drying process is indicated by point A. As described above, the pressure of the processing fluid at this time (1st pressure P1) is 6 MPa and the temperature is 20°C. Therefore, the processing fluid is introduced to the processing chamber 412 as a gas.

[0112] As can be understood from the state diagram, point A specified by the pressure and the temperature is at the boundary between the liquid phase and the gas phase, that is, a position slightly into the region of the gas phase side from the gas-liquid equilibrium state. That is, the pressure at this time is a pressure slightly less than the maximum pressure that the processing fluid at a temperature lower than the critical temperature Tc and in the gas phase can take. In other words, the 1st pressure P1 is set in such a manner as to satisfy this condition. Point A is more preferably as close as possible to the critical point C within a range in which the processing fluid does not liquefy or become supercritical.

[0113] After the pressure in the chamber is increased to the 1st pressure P1, the processing fluid in the supercritical state is introduced to the processing chamber 412. The state of the processing fluid at this time is indicated by point B. The pressure of the processing fluid is greater than the critical pressure Pc, and in the present embodiment, is 11 MPa (2nd pressure P2). In addition, the temperature is set to an appropriate value exceeding the critical temperature Tc.

[0114] Thus, the reason for raising the pressure in two stages, that is, first filling the processing chamber 412 with the processing fluid in a relatively low pressure and gas phase, and then introducing the processing fluid in a higher pressure and supercritical state, is as follows. In the case of directly introducing the supercritical processing fluid in a high pressure into the processing chamber in an atmospheric pressure as in the prior art, sometimes processing failures such as generation of particle adhesion or pattern collapse on the substrate occur. According to the inventors' insight, the reason is that when the processing fluid in a low pressure is introduced into the processing chamber in a high pressure and high density, a part of the processing fluid cooled by adiabatic expansion solidifies or liquefies, and adheres to the substrate.

[0115] To avoid this phenomenon, in the present embodiment, the processing fluid in a gas phase is first introduced into the processing chamber 412, and the pressure in the chamber is raised to a pressure slightly lower than the critical pressure Pc. In this state, the supercritical processing fluid in a higher pressure is introduced. By raising the pressure in the chamber in two stages as such, liquefaction and solidification of the processing fluid in the chamber can be prevented.

[0116] Further, by contacting the processing fluid in a gas phase with the liquid film of the organic solvent covering the front surface of the substrate S, the processing fluid dissolves into the liquid, and has an effect of reducing the surface tension of the liquid. First, by introducing the processing fluid as a gas into the processing chamber 412, the surface tension of the liquid is reduced in advance, and the replacement efficiency when the supercritical processing fluid is introduced can be improved.

[0117] According to the inventors' experiments, in the case of directly introducing the supercritical processing fluid in a pressure of 11 MPa into the processing chamber 412, or in the case of pre-introducing the gas in a pressure of 4 to 5 MPa, sometimes processing failures causing damage to the substrate occur. On the other hand, in the case of setting the pressure of the gas (the first pressure PI) to 6 MPa, such processing failures can be effectively suppressed. If the pressure is further raised, the risk of liquefaction of the processing fluid becomes higher.

[0118] In the case of setting the first pressure PI to 6 MPa and the second pressure P2 to 11 MPa, the pressure difference when the processing fluid in a gas phase is raised from the atmospheric pressure Pa to the first pressure PI is larger than the pressure difference when the supercritical processing fluid is raised from the first pressure PI to the second pressure P2. That is, the processing fluid in a gas phase bears more than half of the pressure difference from the atmospheric pressure Pa to the second pressure P2 which is the final target. Thus, liquefaction or solidification due to the introduction of the processing fluid in a large pressure difference is prevented.

[0119] In the present embodiment, by selectively opening the valves V75 and V76, the processing fluid in a gas phase and the processing fluid in a liquid are switched, and the common piping group 740 serves as their flow paths. Thus, the piping configuration can be simplified, and further, the inclusion of impurities due to the piping system including the valves can be reduced.

[0120] As described above, in the embodiment, the supercritical processing apparatus 4 corresponds to the "substrate processing apparatus" of the present application, and the processing chamber 412 having the processing space SP as the "internal space" functions as the "processing chamber" of the present application. Further, the fluid supply section 457 functions as both the "first supply section" and the "second supply section" of the present application.

[0121] More specifically, the tank 717 functions as the "storage section" of the present application, and the pressurizing pump 715 functions as the "pressurizing section" of the present application. Further, the pipe 736 corresponds to the "first pipe" of the present application, and the valve V76 functions as the "first valve" of the present application. Further, the pipe 732 and the valve V75 function as the "second pipe" and the "second valve" of the present application, respectively. Further, the pipe group 740 constitutes the "introduction flow path" of the present application.

[0122] Further, the tank 717 functions as the "first supply section" of the present application when the processing fluid of gas is sent out through the pipe 736, and functions as the "second supply section" of the present application when the processing fluid of liquid is sent out through the pipe 732. In addition, as shown by a dotted line in FIG. 7, in a case where the processing fluid of gas is sent out from the fluid supply source 700 to the processing chamber 412 through the pipe 737, the fluid supply source 700 corresponds to the "first supply section" of the present application, and the pipe 737 corresponds to the "first pipe" of the present application. Figure 5

[0123] Further, the control apparatus 9 of the embodiment, and more specifically, the supercritical processing control section 97 functions as the "control section" of the present application. Further, the heaters 725 and 726 correspond to the "first heater" of the present application, and the heater 719 corresponds to the "second heater" of the present application. Further, the valve V74 functions as the "third valve" of the present application, and the pipe 733 functions as the "return pipe" of the present application.

[0124] Further, the present application is not limited to the embodiment, and various modifications can be made without departing from the gist thereof. For example, the fluid supply section 457 of the embodiment includes a flow meter or a filter and the like which are generally provided in a flow path of a processing fluid, but is not directly related to the present application. Even if these are omitted, the present application can be established.

[0125] Further, for example, in the embodiment, the introduction of the processing fluid into the processing chamber 412 and the discharge of the processing fluid from the processing chamber 412 are performed individually on each of the upper side and the lower side of the support tray 415. However, this is not an essential requirement of the technical idea of the present application.

[0126] ​Further, in the embodiment, the processing fluid of gas and liquid is taken out from a single tank 717, and the tank 717 functions as both the "first supply part" and the "second supply part" of the present application. However, they can be provided as independent configurations. For example, a configuration in which gas and liquid are stored separately can be provided.

[0127] Further, the various chemicals used in the processing of the embodiment are examples of chemicals, and various chemicals can be used instead of them if they are consistent with the technical idea of the present application.

[0128] Further, in the substrate processing apparatus of the present application, the control part can be configured to, for example, open the first valve, fill the internal space with the processing fluid at the first pressure, close the first valve, and open the second valve to fill the internal space with the processing fluid at the second pressure, as explained above with reference to the specific embodiment. According to this configuration, the switching from the processing fluid at the first pressure to the processing fluid at the second pressure can be performed surely.

[0129] Further, for example, the storage part can be configured to store the processing fluid in liquid form pressurized to the first pressure, and the first pipe can be connected in communication with the space above the liquid surface, and the second pipe can be connected in communication with the space below the liquid surface, and the processing fluid in gas form above the liquid surface can be sent to the first pipe, thereby functioning as the first supply part. According to this configuration, the processing fluid in gas and liquid form can be stored in a single storage part, and the apparatus configuration can be simplified.

[0130] In this case, the pressurizing part can be configured to pressurize the processing fluid at the first pressure sent from the storage part to the second pipe to the second pressure and output it. According to this configuration, the processing fluid at the first pressure in gas form and the processing fluid at the second pressure in liquid form can be supplied from a single storage part.

[0131] Further, for example, the second supply part can be configured to have a return pipe connected to the second pipe between the pressurizing part and the second valve, and connected to the storage part via the third valve. In this case, the pressurizing part can be configured to pressurize the processing fluid supplied from the external supply source and make it flow into the storage part in a state in which the second valve is closed and the third valve is opened by the control part. According to this configuration, the processing fluid can be stored in the storage part after being pressurized by the pressurizing part, and therefore the processing fluid itself supplied from the more upstream side can be at a lower pressure than the first pressure. That is, the degree of freedom of the processing fluid with respect to the supply source is increased.

[0132] Further, for example, a first heater that heats the treatment fluid flowing through the introduction flow path from the second pipe can be provided. According to this configuration, the treatment fluid can be supercritical by heating the treatment fluid to a temperature above the critical temperature, so the second supply portion does not need to output the treatment fluid in a supercritical state.

[0133] Further, for example, a second heater that heats the treatment fluid stored in the storage portion can be provided. According to this configuration, the decrease in the internal pressure of the storage portion that can occur due to the consumption of the stored treatment fluid can be compensated for by heating, and the pressure of the treatment fluid being delivered can be stably maintained.

[0134] Further, for example, the first pressure can be configured to be lower than the pressure at which the treatment fluid liquefies at the temperature of the treatment fluid delivered from the first supply portion. According to this configuration, the treatment fluid delivered from the first supply portion can be reliably maintained in a gaseous state.

[0135] Further, according to the inventor's insight, the internal pressure of the processing chamber is sufficiently increased in advance by the introduction of the gas, thereby preventing liquefaction or solidification when the critical treatment fluid is subsequently introduced. For example, the pressure difference between the atmospheric pressure and the first pressure can be set to be greater than the pressure difference between the first pressure and the second pressure.

[0136] The application has been described above with reference to specific embodiments. The description is not intended to be construed as a limitation on the present application. Those skilled in the art can readily produce various modifications of the disclosed embodiments without departing from the scope of the application, with the reference to the description of the application. Therefore, it is considered that the appended claims encompass the modifications or embodiments.

[0137] [Industrial Applicability]

[0138] The present application can be applied to the entire technology of processing a substrate with a treatment fluid in a supercritical state in a processing chamber.

[0139] [Explanation of Symbols]

[0140] 4 supercritical processing device (substrate processing device)

[0141] 97 supercritical processing control portion (control portion)

[0142] 412 processing chamber

[0143] 457 fluid supply portion (first supply portion, second supply portion)

[0144] 700 fluid supply source (first supply portion)

[0145] 715 pressurizing pump (pressurizing portion)

[0146] 717 tank (storage section, first supply section, second supply section)

[0147] 719 heater (second heater)

[0148] 725, 726 heater (first heater)

[0149] 732 piping (second piping)

[0150] 736 piping (first piping)

[0151] 733 piping (return piping)

[0152] 737 piping (first piping)

[0153] 740 piping group (introduction flow path)

[0154] SP processing space (internal space)

[0155] V74 valve (third valve)

[0156] V75 valve (second valve)

[0157] V76 valve (first valve)

Claims

1. A substrate processing apparatus that processes a substrate with a processing fluid in a supercritical state, comprising: a processing chamber having an internal space capable of accommodating the substrate; a first supply section that supplies the processing fluid as a gas pressurized to a first pressure lower than a critical pressure; a second supply section that supplies the processing fluid at a second pressure higher than the critical pressure; an introduction flow path that communicates with the internal space and introduces the processing fluid into the internal space; a first pipe that connects the first supply section and the introduction flow path via a first valve; a second pipe that connects the second supply section and the introduction flow path via a second valve; and a control section that controls the first valve and the second valve to selectively flow the processing fluid at the first pressure and the processing fluid at the second pressure into the internal space; and wherein the second supply section has: a storage section that stores the processing fluid in a liquid state; and a pressurizing section that is interposed in the second pipe from the storage section to the second valve, pressurizes the processing fluid to the second pressure, and sends it out.

2. The substrate processing apparatus according to claim 1, wherein the control section opens the first valve, fills the internal space with the processing fluid at the first pressure, closes the first valve, and opens the second valve to fill the internal space with the processing fluid at the second pressure.

3. The substrate processing apparatus according to claim 1, wherein the storage section stores the processing fluid in a liquid state pressurized to the first pressure, and connects the first pipe in a manner that communicates with a space above a liquid surface of the processing fluid, and connects the second pipe in a manner that communicates with a space below the liquid surface, and functions as the first supply section by sending the processing fluid in a gaseous state above the liquid surface to the first pipe.

4. The substrate processing apparatus according to claim 3, wherein the pressurizing section pressurizes the processing fluid at the first pressure sent from the storage section to the second pipe to the second pressure and outputs it.

5. The substrate processing apparatus according to any one of claims 1 to 4, wherein the second supply section has a return pipe connected to the second pipe between the pressurizing section and the second valve, and connected to the storage section via a third valve.

6. The substrate processing apparatus according to claim 5, wherein in a state where the second valve is closed by the control section and the third valve is opened, the pressurizing section pressurizes the processing fluid supplied from an external supply source and flows it into the storage section.

7. The substrate processing apparatus according to any one of claims 1 to 4, comprising a first heater that heats the processing fluid flowing through the introduction flow path from the second pipe.

8. The substrate processing apparatus according to any one of claims 1 to 4, comprising a second heater that heats the processing fluid stored in the storage section. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 9. The substrate processing apparatus according to any one of claims 1 to 4, wherein the first pressure is lower than a pressure at which the processing fluid is liquefied at a temperature of the processing fluid delivered by the first supply section.

10. The substrate processing apparatus according to any one of claims 1 to 4, wherein a pressure difference between an atmospheric pressure and the first pressure is larger than a pressure difference between the first pressure and the second pressure.

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