Substrate processing equipment

Abstract

To suggest the preferred arrangement of a filter in a flow channel of a process fluid in the technique of processing a substrate with a supercritical processing fluid.SOLUTION: A substrate processing device includes a processing chamber including an internal space that can accommodate a substrate, a supply part that can supply a process fluid as liquid, a heating part that heats the liquid process fluid supplied from the supply part at or above a supercritical temperature of the process fluid and makes the process fluid transit to a supercritical state, a flow channel formation part that forms a flow channel of the process fluid from the fluid supply part to the processing chamber through the heating part, a first filter part that is inserted in a flow channel between the supply part and the heating part and filters the liquid process fluid, and a second filter part that is inserted in a flow channel between the heating part and the processing chamber and filters the liquid process fluid in the supercritical state.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technology for accommodating a substrate in a processing chamber and processing the substrate with a supercritical processing fluid. [Background Art]

[0002] Processing steps for various substrates such as semiconductor substrates, glass substrates for display devices include those that treat the surface of the substrate with various processing fluids. Wet processing using liquids such as chemical solutions and rinsing liquids as processing fluids has been widely performed conventionally. In recent years, processing using a supercritical processing fluid has also been put into practical use to dry substrates after the wet processing. It is particularly beneficial in the drying process of substrates having a patterned surface on which fine patterns are formed. This is because the processing fluid in the supercritical state has lower surface tension than liquid, and has a characteristic of penetrating deep into the gaps between patterns. By using said processing fluid, it is possible to perform the drying process efficiently. It is also possible to reduce the risk of pattern collapse caused by surface tension during drying.

[0003] For example, in the substrate processing apparatus described in Patent Document 1, the substrate is placed on a flat support member and accommodated in the processing chamber. In the processing chamber, a processing fluid is introduced into each of the space above the substrate and the space below the support member, a laminar flow of the processing fluid is formed in these spaces to process the substrate. A filter for filtering the processing fluid and removing contamination-causing substances that may be contained therein is interposed in each of the pipe for supplying the processing fluid to the upper side of the substrate and the pipe for supplying the processing fluid to the lower side of the substrate. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2023-036123 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In substrate processing technology that uses supercritical fluids to process substrates, it is common for the processing fluid to undergo phase transitions between several states, such as gas, liquid, and supercritical states, during the processing process. Such phase transitions can also occur within the piping through which the processing fluid flows. On the other hand, the desired specifications for filters installed in the piping system vary depending on whether the fluid being processed is a gas or a liquid. In other words, if the type of fluid flowing and the purpose of its placement do not match the filter specifications, problems may arise such as not achieving the desired filtering performance or placing excessive stress on the filter or piping, negatively impacting them.

[0006] Therefore, the placement of filters in the piping system is crucial for obtaining good filtering results, but this point is not addressed in detail in the conventional technologies described above. Thus, careful consideration is required regarding the placement of filters in the piping system for equipment used for processing supercritical fluids, but sufficient knowledge from this perspective has not yet been accumulated, and the establishment of technologies for optimizing filter placement is desired.

[0007] This invention has been made in view of the above-mentioned problems, and aims to propose a preferred arrangement of filters in the flow path of a processing fluid in a technology for processing a substrate with a supercritical processing fluid. [Means for solving the problem]

[0008] One aspect of this invention is a substrate processing apparatus for processing a substrate with a processing fluid in a supercritical state, comprising: a processing chamber having an internal space capable of accommodating the substrate; a fluid supply unit capable of supplying the processing fluid as a liquid; a heating unit that heats the liquid processing fluid supplied from the fluid supply unit to a temperature above the critical temperature of the processing fluid to transition it to a supercritical state; a flow path forming unit that forms a flow path for the processing fluid from the fluid supply unit through the heating unit to the processing chamber; a first filter unit interposed in the flow path between the fluid supply unit and the heating unit to filter the liquid processing fluid; and a second filter unit interposed in the flow path between the heating unit and the processing chamber to filter the processing fluid in a supercritical state. The first filter section has a plurality of filter units of the same structure connected in parallel to one another. It is.

[0009] In this configuration, in order to supply a supercritical processing fluid to the processing chamber, the processing fluid supplied as a liquid from the fluid supply unit is heated and made supercritical by the heating unit before being introduced into the processing chamber. A first filter unit is provided in the liquid flow path from the fluid supply unit to the heating unit, and a second filter unit is provided in the flow path of the supercritical processing fluid (hereinafter sometimes simply referred to as "supercritical fluid") from the heating unit to the processing chamber.

[0010] Thus, the fluid flow path can be clearly zoned, with the heating section in between, into an area for liquid flow upstream and an area for supercritical fluid flow downstream. By placing filters in each area, it becomes possible to apply filters specifically suited to the fluid being processed. Specifically, a filter suitable for liquid processing can be used in the first filter section, and a filter suitable for supercritical fluid processing can be used in the second filter section. [Effects of the Invention]

[0011] As described above, according to the present invention, the flow path for transporting the processing fluid into the processing chamber is clearly zoned into an area for handling liquids and an area for handling supercritical fluids, and filters are placed in each area. Therefore, by selecting a filter according to the fluid being handled, its performance can be fully utilized, making it possible to process the substrate with a clean processing fluid from which contaminants have been removed. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows a schematic configuration of a substrate processing system equipped with one embodiment of the substrate processing apparatus according to the present invention. [Figure 2] This is a side view showing the overall configuration of the wet processing apparatus. [Figure 3] This is a diagram illustrating the operation of a wet processing apparatus. [Figure 4] This is a side view showing the configuration of a supercritical fluid processing apparatus. [Figure 5] This figure shows the details of the supply and discharge routes for the processed fluid. [Figure 6] This flowchart shows the processes performed by the supercritical fluid processing unit. [Figure 7] This figure shows the pressure changes inside the processing chamber and storage tank. [Figure 8] This figure shows a second embodiment of the substrate processing device. [Figure 9] This figure shows a third embodiment of the substrate processing apparatus. [Figure 10] This figure shows a fourth embodiment of the substrate processing device. [Modes for carrying out the invention]

[0013] <First Embodiment> FIG. 1 is a diagram showing a schematic configuration of a substrate processing system equipped with a first embodiment of a substrate processing apparatus according to the present invention. This substrate processing system 1 is a processing system for supplying a processing liquid to the upper surface of various substrates such as semiconductor wafers to perform wet processing on the substrate, and then drying the substrate, and has a system configuration suitable for carrying out the substrate processing method according to the present invention. The substrate processing system 1 includes, as its main components, a wet processing apparatus 2, a substrate transfer apparatus 3, a supercritical processing apparatus 4, and a control apparatus 9.

[0014] The wet processing apparatus 2 receives a substrate to be processed and performs predetermined wet processing. The content of the processing is not particularly limited. Wet processing includes development processing, cleaning processing, and the like. After development processing or the like, a liquid filled state in which an organic solvent such as an IPA liquid is filled on the pattern formation surface of the substrate is created. The substrate transfer apparatus 3 unloads and transfers the substrate from the wet processing apparatus 2 while the liquid filled state is maintained, and loads the substrate into the supercritical processing apparatus 4. The supercritical processing apparatus 4 corresponds to the substrate processing apparatus according to the present invention, and performs a drying process (supercritical drying process) using a processing fluid in a supercritical state on the loaded substrate. These apparatuses are installed in a clean room. Therefore, the substrate transfer apparatus 3 transfers the substrate in an air atmosphere under atmospheric pressure.

[0015] The control apparatus 9 controls the operations of each of these apparatuses to implement predetermined processing. For this purpose, the control apparatus 9 includes a CPU 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 control programs executed by the CPU 91. The interface 94 exchanges information with users and external apparatuses. The operations of the apparatus described below are implemented by the CPU 91 executing a control program pre-stored in the storage 93 and causing each part of the apparatus to perform predetermined operations.

[0016] When the CPU 91 executes a predetermined control program, functional blocks including a wet processing control unit 95 that controls the operation of the wet processing apparatus 2, a conveyance control unit 96 that controls the operation of the substrate conveyance apparatus 3, and a supercritical processing control unit 97 that controls the operation of the supercritical processing apparatus 4 are implemented by software in the control apparatus 9. Note that at least a part of each of these functional blocks may be configured by dedicated hardware.

[0017] As the "substrate" in the present embodiment, various substrates such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FED (Field Emission Display), substrates for optical disks, substrates for magnetic disks, and substrates for magneto-optical disks are applicable. In the following, a substrate processing apparatus mainly used for processing disk-shaped semiconductor wafers will be taken as an example and described with reference to the drawings. However, the present invention is also similarly applicable to the processing of various substrates exemplified above. Furthermore, various shapes of substrates are also applicable.

[0018] Furthermore, in the following description, a substrate having a pattern formed only on one main surface is used as an example. Here, the side of the main surface on which a pattern or the like is formed is referred to as a "front surface", and the opposite main surface on which no pattern is formed is referred to as a "back surface". Furthermore, the main surface of the substrate facing downward is referred to as a "lower surface", and the main surface of the substrate facing upward is referred to as an "upper surface". In the following description, the upper surface will be described as the front surface.

[0019] FIG. 2 and FIG. 3 are diagrams showing a configuration example of a wet processing apparatus. More specifically, FIG. 2 is a side view showing the overall configuration of the wet processing apparatus, and FIG. 3 is a diagram for explaining the operation of the wet processing apparatus. This wet processing apparatus 2 is an apparatus that processes a substrate by supplying a processing liquid onto the upper surface of the substrate S. The operation of the wet processing apparatus 2 is controlled by the wet processing control unit 95 of the control apparatus 9.

[0020] The wet processing apparatus 2 supplies a processing liquid to the surface (pattern forming surface) Sa of the substrate S to perform wet processing such as surface treatment and cleaning of the substrate S. For this purpose, the wet processing apparatus 2 is equipped with a substrate holding section 21, a splash guard 22, and processing liquid supply sections 23 and 24 inside the processing chamber 200. These operations are controlled by a wet processing control section 95 provided in the control device 9. The substrate holding section 21 has a disc-shaped spin chuck 211 with a diameter approximately the same as that of the substrate S, and a plurality of chuck pins 212 are provided on the periphery of the spin chuck 211. By having the chuck pins 212 contact the periphery of the substrate S and support the substrate S, the spin chuck 211 can hold the substrate S in a horizontal position with the substrate S spaced apart from its upper surface.

[0021] The spin chuck 211 is supported by a rotating support shaft 213 extending downward from the center of its lower surface, so that its upper surface is horizontal. The rotating support shaft 213 is rotatably supported by a rotating mechanism 214 attached to the bottom of the processing chamber 200. The rotating mechanism 214 incorporates a rotating motor (not shown), and when the rotating motor rotates in response to a control command from the control device 9, the spin chuck 211, which is directly connected to the rotating support shaft 213, rotates around the rotation axis AX shown by the dashed line. In Figure 2, the up and down direction is the vertical direction. As a result, the substrate S is rotated around the rotation axis AX while remaining in a horizontal position.

[0022] A splash guard 22 is provided so as to surround the substrate holding portion 21 from the side. The splash guard 22 has a roughly cylindrical cup 221 provided so as to cover the periphery of the spin chuck 211, and a liquid receiving portion 222 provided below the outer circumference of the cup 221. The cup 221 moves up and down in response to a control command from the control device 9. As shown in Figure 2, the cup 221 moves up and down between a lower position where the upper end of the cup 221 is below the periphery of the substrate S held by the spin chuck 211, and an upper position where the upper end of the cup 221 is above the periphery of the substrate S, as shown in Figure 3.

[0023] When the cup 221 is in the lower position, as shown in Figure 2, the substrate S held by the spin chuck 211 is exposed to the outside of the cup 221. This prevents the cup 221 from becoming an obstacle when, for example, loading or unloading the substrate S into or out of the spin chuck 211.

[0024] Furthermore, when the cup 221 is in the upper position, it surrounds the periphery of the substrate S held by the spin chuck 211, as shown in Figure 3. This prevents the processing liquid that is shaken off the periphery of the substrate S during liquid supply (described later) from scattering into the chamber 200, and ensures reliable collection of the processing liquid. In other words, droplets of processing liquid that are shaken off the periphery of the substrate S as the substrate S rotates adhere to the inner wall of the cup 221 and flow downward, where they are collected by the liquid receiving section 222 located below the cup 221. Multiple cups may be arranged concentrically to collect multiple processing liquids individually.

[0025] The processing liquid supply unit 23 has a structure in which a nozzle 234 is attached to the tip of an arm 233 that extends horizontally from a pivot shaft 232 rotatably mounted on a base 231 fixed to the processing chamber 200. When the pivot shaft 232 rotates in response to a control command from the control device 9, the arm 233 swings, and the nozzle 234 at the tip of the arm 233 moves between a retracted position, where it is moved to the side from above the substrate S as shown in Figure 2, and a processing position above the substrate S as shown in Figure 3.

[0026] The nozzle 234 is connected to a processing liquid supply source 238. When an appropriate processing liquid is supplied from the processing liquid supply source 238, the processing liquid is discharged from the nozzle 234 toward the substrate S. As shown in Figure 2B, the spin chuck 211 rotates at a relatively low speed to rotate the substrate S, and the processing liquid L1 is supplied from the nozzle 234, which is positioned above the center of rotation of the substrate S, thereby processing the surface Sa of the substrate S with the processing liquid L1. The processing liquid L1 can be a liquid with various functions such as a developer, etching solution, washing solution, or rinsing solution, and its composition is arbitrary. In addition, a combination of multiple types of processing liquids may be used to perform the processing.

[0027] The other processing liquid supply unit 24 also has a configuration corresponding to the first processing liquid supply unit 23 described above. That is, the second processing liquid supply unit 24 has a base 241, a pivot shaft 242, an arm 243, a nozzle 244, etc., and these configurations are equivalent to those of the first processing liquid supply unit 23. The pivot shaft 242 rotates in response to a control command from the control device 9, causing the arm 243 to swing. The nozzle 244 at the tip of the arm 243 supplies processing liquid to the surface Sa of the substrate S.

[0028] In this embodiment, the second processing liquid supply unit 24 is used to form a liquid film on the substrate S after wet processing to prevent drying. That is, the substrate S after wet processing is transported to the supercritical processing apparatus 4 to undergo supercritical drying processing, but in order to prevent the surface of the substrate S from being exposed and oxidized during transport, or for the fine patterns formed on the surface to collapse, the substrate S is transported with its surface covered with a paddle-shaped liquid film.

[0029] The liquid that constitutes the liquid film is a substance with a lower surface tension than water, which is the main component of the treatment solution used in the cleaning process, such as an organic solvent like isopropyl alcohol (IPA) or acetone. These organic solvents are supplied from the organic solvent supply source 248.

[0030] Here, the wet processing apparatus 2 is provided with two sets of processing liquid supply units, but the number of processing liquid supply units, their structure, and function are not limited to this. For example, there may be only one set of processing liquid supply units, or there may be three or more sets. Also, one processing liquid supply unit may be equipped with multiple nozzles. For example, multiple nozzles may be provided at the tip of a single arm. Furthermore, in addition to the mode in which the processing liquid is discharged with the nozzles positioned at a predetermined position as described above, a mode in which the processing liquid is discharged while the nozzles scan and move along the surface Sa of the substrate S may also be included.

[0031] Returning to Figure 1, let's continue the explanation. The substrate transport device 3 is equipped with a transport robot 30, which has a hand 31 at the end of an extendable and rotatable arm. The hand 31 can support the substrate by partially contacting the underside of the substrate, and as shown by the dotted line in Figure 1, it can move forward and backward relative to both the wet processing device 2 and the supercritical processing device 4. This allows for the loading and unloading of substrates to and from the wet processing device 2 and the supercritical processing device 4, respectively. The operation of the transport robot 30 is controlled by the transport control unit 96 of the control device 9. There are many known technologies for this type of transport robot, and in this embodiment, they can be appropriately selected and used, so a detailed explanation will be omitted.

[0032] Figure 4 is a side view showing the configuration of the supercritical fluid processing apparatus. The supercritical fluid processing apparatus 4 corresponds to the first embodiment of the substrate processing apparatus according to the present invention, and is an apparatus that performs a drying treatment on a substrate S after wet processing using a processing fluid in a supercritical state. More specifically, the supercritical fluid processing apparatus 4 is an apparatus that receives a substrate S after wet processing, replaces the liquid remaining in the substrate S with a processing fluid in a supercritical state, and then discharges the processing fluid to ultimately bring the substrate S to a dry state.

[0033] The supercritical processing apparatus 4 comprises a processing unit 41, a transfer unit 43, and a supply unit 45. The processing unit 41 is the main unit for executing the supercritical drying process. The transfer unit 43 receives the wet-processed substrate S transported by the substrate transport device 3 and loads it into the processing unit 41, and also transfers the processed substrate S from the processing unit 41 to an external transport device. The supply unit 45 supplies the chemical substances, power, and energy necessary for the process to the processing unit 41 and the transfer unit 43. These operations are controlled by the control device 9, in particular by the supercritical processing control unit 97.

[0034] The processing unit 41 has a structure in which a processing chamber 412 is mounted on a base 411. The processing chamber 412 is composed of a combination of several metal blocks, and its interior is hollow, forming a processing space SP. The substrate S to be processed is brought into the processing space SP and processed. A slit-shaped opening 421 extending elongated in the X direction is formed on the (-Y) side of the processing chamber 412. The processing space SP and the external space are in communication through the opening 421. The cross-sectional shape of the processing space SP is generally the same as the opening shape of the opening 421. That is, the processing space SP has a cross-sectional shape that is long in the X direction and short in the Z direction, and is a cavity extending in the Y direction.

[0035] A lid member 413 is provided on the (-Y) side of the processing chamber 412 so as to close the opening 421. By closing the opening 421 of the processing chamber 412 with the lid member 413, an airtight processing container is formed. This makes it possible to process the substrate S under high pressure in the internal processing space SP. A flat support tray 415 is mounted horizontally on the (+Y) side of the lid member 413. The upper surface of the support tray 415 is a support surface on which the substrate S can be placed. The lid member 413 is supported so as to be able to move horizontally in the Y direction by a support mechanism (not shown).

[0036] The lid member 413 is movable forward and backward relative to the processing chamber 412 by a forward / backward mechanism 453 provided on the supply unit 45. Specifically, the forward / backward mechanism 453 has a linear motion mechanism such as a linear motor, linear guide, ball screw mechanism, solenoid, or air cylinder. Such a linear motion mechanism moves the lid member 413 in the Y direction. The forward / backward mechanism 453 operates in response to control commands from the control device 9.

[0037] As the lid member 413 moves in the (-Y) direction, it separates from the processing chamber 412, and as shown by the dotted line, the support tray 415 is pulled out of the processing space SP through the opening 421, making the support tray 415 accessible. That is, it becomes possible to place a substrate S on the support tray 415 and to remove a substrate S that is placed on the support tray 415. On the other hand, as the lid member 413 moves in the (+Y) direction, the support tray 415 is housed inside the processing space SP. If a substrate S is placed on the support tray 415, the substrate S is transported into the processing space SP together with the support tray 415.

[0038] The processing space SP is sealed when the lid member 413 moves in the (+Y) direction and closes the opening 421. A sealing member 422 is provided between the (+Y) side surface of the lid member 413 and the (-Y) side surface of the processing chamber 412, maintaining the airtight state of the processing space SP. The sealing member 422 is made of rubber, for example. In addition, the lid member 413 is fixed to the processing chamber 412 by a locking mechanism (not shown). Thus, in this embodiment, the lid member 413 can be switched between a closed state (solid line) in which the opening 421 is closed and the processing space SP is sealed, and a separated state (dotted line) in which it is far enough away from the opening 421 that the substrate S can be inserted and removed.

[0039] With the processing space SP airtight, processing of the substrate S is performed within the processing space SP. In this embodiment, a fluid supply unit 457 provided in the supply unit 45 delivers a processing fluid of a substance usable for supercritical processing, such as carbon dioxide, as the processing fluid, and further pressurizes the processing fluid in the processing chamber 412 to bring it to a supercritical state. The processing fluid is supplied to the processing unit 41 in gaseous or liquid form. Carbon dioxide is a suitable chemical substance for supercritical drying processing because it becomes supercritical at relatively low temperatures and low pressures, and has the property of dissolving organic solvents, which are frequently used in substrate processing, well. The critical point at which carbon dioxide becomes supercritical is a pressure (critical pressure) of 7.38 MPa and a temperature (critical temperature) of 31.1°C.

[0040] When the processing fluid is filled into the processing space SP 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. In this way, the substrate S is processed by the supercritical processing fluid in the processing chamber 412. The supply unit 45 is provided with a fluid recovery unit 455, and the fluid after processing 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.

[0041] The processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S supported therein. Specifically, the processing space SP has a roughly rectangular cross-sectional shape that is wider horizontally than the width of the support tray 415 and greater vertically than the combined height of the support tray 415 and the substrate S, and has a depth that can accommodate the support tray 415. Thus, the processing space SP has a shape and volume that can accommodate 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.

[0042] The fluid supply unit 457 supplies processing fluid to the processing space SP further to the (+Y) side than the (+Y) side end of the substrate S. On the other hand, the fluid recovery unit 55 discharges the processing fluid that has flowed through the space above the substrate S and the space below the support tray 415 within the processing space SP, further to the (-Y) side than the (-Y) side end of the substrate S. As a result, a laminar flow of processing fluid is formed within the processing space SP, both above the substrate S and below the support tray 415, moving from the (+Y) side to the (-Y) side.

[0043] The supercritical fluid processing control unit 97 of the control device 9 determines the pressure and temperature in the processing space SP based on the detection results of a detection unit (not shown), and controls the fluid supply unit 457 and the fluid recovery unit 455 based on these results. This ensures that the supply of processing fluid to the processing space SP and the discharge of processing fluid from the processing space SP are appropriately managed, and the pressure and temperature in the processing space SP are adjusted according to a predetermined processing recipe.

[0044] The transfer unit 43 is responsible for transferring the substrate S between the substrate transport device 3 and the support tray 415. For this purpose, the transfer unit 43 comprises a main 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 supported by a support mechanism (not shown) so as to be movable in the Z direction relative to the main body 431. A base member 435 having a substantially horizontal upper surface is attached to the upper part of the lifting member 433. A plurality of lift pins 437 are erected upward from the upper surface of the base member 435. Each of the lift pins 437 supports the substrate S in a horizontal position from below by its upper end contacting the lower surface of the substrate S. In order to stably support the substrate S in a horizontal position, it is desirable to provide three or more lift pins 437 whose upper end heights are equal to each other.

[0045] 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 a linear motion mechanism such as a linear motor, linear guide, ball screw mechanism, solenoid, or air cylinder, and such a linear motion mechanism moves the lifting member 433 in the Z direction. The lifting mechanism 451 operates in response to control commands from the control device 9.

[0046] The base member 435 moves up and down as the lifting member 433 moves up and down, and multiple lift pins 437 move up and down in conjunction with it. This enables the transfer of the substrate S between the transfer unit 43 and the support tray 415. More specifically, as shown by the dotted line in Figure 4, the substrate S is transferred when the support tray 415 is pulled out of the chamber. For this purpose, the support tray 415 is provided with through holes 419 for inserting the lift pins 437. When the base member 435 rises, the upper ends 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 being transported by the transport robot 30 is transferred from the hand 31 of the transport robot 30 to the lift pins 437. As the lift pins 437 descend, the substrate S is transferred from the lift pins 437 to the support tray 415. The substrate S can be unloaded by the reverse procedure described above.

[0047] Next, the supply path for the processing fluid to the processing chamber 412 and the discharge path for the processing fluid from the processing chamber 412 will be described in more detail. Briefly above, it was explained that the processing fluid is supplied from the fluid supply unit 457 to the processing chamber 412, and the processing fluid is recovered from the processing chamber 412 to the fluid recovery unit 455. In the actual apparatus, the fluid supply unit 457 and the fluid recovery unit 455 have the following configurations.

[0048] Figure 5 shows the details of the supply and discharge paths of the processing fluid. Note that in Figure 5, for illustrative purposes, the orientation of the processing chamber 412 is reversed compared to Figure 4. That is, in Figure 4, the processing fluid is introduced into the processing chamber 412 from the right side of the page and discharged to the left side. On the other hand, in Figure 5, the opposite is true: the processing fluid is introduced into the processing chamber 412 from the left side of the page and discharged to the right side. In other words, the side of the processing chamber 412 in Figure 5 is shown as being opposite to the side of the processing chamber 412 in Figure 4.

[0049] 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 groups of piping 730 and 740 connecting them. These operate in response to control commands from the supercritical processing control unit 97.

[0050] The fluid supply source 700 outputs a substance (carbon dioxide in this embodiment) that acts as a processing fluid in the supercritical process as needed. The fluid supply source 700 may be provided as part of the substrate processing system 1, and can be composed of a container for storing the substance, such as a cylinder. Alternatively, it may be an external supply source provided separately from the substrate processing system 1.

[0051] A pipe 731, which is part of a piping group 730, is connected to the fluid supply source 700. The processed fluid delivered from the fluid supply source 700 is transported through the pipe 731 in a rightward direction in Figure 1. Along the direction of flow of the processed fluid, valves V70, V71, a purifier 711, a filter 712, a condenser 713, and valve V72 are interposed in this order within the pipe 731. Valve V70 is, for example, a pressure regulating valve that has the function of adjusting the pressure of the processed fluid transported through the pipe 731. The other valves V71 and V72 are on-off valves that switch the fluid flow on and off.

[0052] Valve V70 allows the processed fluid at a pressure specified by a control command from the supercritical fluid processing control unit 97 to flow through piping 731. The purifier 711 and filter 712 remove impurities contained in the processed fluid and improve its purity. The condenser 713 condenses the processed fluid that is sent out as a gas from the fluid supply source 700. When valves V71 and V72 are opened, the processed fluid is output from piping 731.

[0053] Piping 731 merges with piping 735, which is connected to the storage tank 717 (described later), on the output side of valve V72. After the merge, piping 732 is equipped with a condenser 714, a pressure pump 715, and a filter 716. The condenser 714 is provided to more reliably maintain the liquid phase state of the processing fluid. The pressure pump 715 pressurizes and delivers the liquid processing fluid. The filter 716 removes impurities from the processing fluid.

[0054] Piping 732 branches into two pipes 733 and 734 at the output side of filter 716. Piping 733 is connected to the top of storage tank 717, with valve V74, which is an on / off valve, inserted along its length. Piping 734 also has valve V75, which is an on / off valve, inserted along its length.

[0055] The storage tank 717 is a high-pressure vessel that has the function of storing pressurized liquid processing fluid. The storage tank 717 is equipped with a level sensor 718 to manage the liquid level. Therefore, the internal space of the storage tank 717 is not liquid-tight, and vaporized processing fluid is stored in the space above the liquid level under a pressure similar to that of the liquid. In addition, a heater 719 is attached to the storage tank 717, and in response to control commands from the supercritical processing control unit 97, the heater 719 can heat the processing fluid inside the tank.

[0056] A pipe 735 is connected to the bottom of the storage tank 717, and pipe 735 merges with pipe 731 and connects to pipe 732. When valve V73, an on / off valve inserted in pipe 735, is opened, the liquid of the processing fluid in the storage tank 717 flows into pipe 732 via pipe 735. If valve V74 on pipe 733 is further opened, a recirculation channel is formed that allows the fluid to return from the storage tank 717 to the storage tank 717 via pipes 735, 732, and 733. By circulating the processing fluid through this recirculation path and pressurizing the processing fluid with a pressure pump 715, the pressure of the processing fluid can be increased in stages. Finally, the processing fluid is stored in the storage tank 717 at a pressure specified by a control command from the supercritical processing control unit 97.

[0057] An output pipe 736 is connected to the top of the storage tank 717, and pipe 736 merges with pipe 734 via a valve V76, which is an on / off valve. From pipe 736, a gaseous processing fluid that fills the upper part of the internal space of the storage tank 717 is output. From pipe 741, where pipes 734 and 736 merge, a gaseous processing fluid flows in when valve V76 is open, and a liquid processing fluid flows in when valve V75 is open.

[0058] Thus, the purification unit 710 of the fluid supply unit 457 has the function of removing impurities from the processing fluid supplied from the fluid supply source 700 and then selectively outputting the processing fluids required for subsequent processing, specifically the gas phase and the liquid phase.

[0059] Pipe 741 is part of a group of pipes 740 that constitute an introduction channel for introducing the processing fluid from the purification unit 710 to the processing chamber 412. Pipe 741 branches into two pipes 743 and 744, each equipped with filters 721 and 722, respectively. These pipes 743 and 744 merge to form pipe 745, which then branches into two more pipes 747 and 748.

[0060] In piping 742, a flow meter 723, a heater 725, and a valve V78 (which acts as an on-off valve) are inserted in that order along the direction of fluid flow (to the right in the figure), and piping 742 is ultimately connected to the processing chamber 412. More specifically, piping 742 communicates with the internal space SP above the support tray 415 (Figure 4) that supports the substrate S. On the other hand, in piping 743, a flow meter 724, a heater 726, and a valve V79 (which acts as an on-off valve) are inserted in that order along the direction of fluid flow. And piping 742 communicates with the internal space SP of the processing chamber 412 below the support tray 415 (Figure 4) that supports the substrate S. As a result, the processing fluid is supplied to the spaces above and below the substrate S placed on the support tray 415 in the internal space SP.

[0061] Flow meters 723 and 724 measure the flow rate of the processing fluid at their respective locations and transmit the results to the supercritical fluid processing control unit 97. Heaters 725 and 726 heat the processing fluid to a predetermined temperature in response to control commands from the supercritical fluid processing control unit 97. Filters 727 and 728 ultimately remove impurities from the processing fluid introduced into the processing chamber 412.

[0062] In this way, the fluid supply unit 457 can supply the processing chamber 412 with a cleaned processing fluid whose temperature and pressure have been adjusted to predetermined target values. The sequence of supplying the processing fluid from the fluid supply unit 457 to the processing chamber 412 will be described in detail later.

[0063] The processing fluid supplied to the processing chamber 412 is delivered from the storage tank 717, and the processing fluid is stored in the storage tank 717 under pressure from the pressure pump 715. Therefore, the pressure of the processing fluid delivered from the fluid supply source 700 may be lower than the pressure required for processing. If the fluid supply source 700 can stably deliver processing fluid at a pressure suitable for processing, the gaseous processing fluid may be supplied directly from the fluid supply source 700 via the piping 737, as shown by the dotted line in Figure 5, instead of taking it from the storage tank 717. Alternatively, the pressure-regulated processing fluid may be supplied from the output side of valve V70.

[0064] As described above, in the fluid supply unit 457 of this embodiment, the purification unit 710 has the function of purifying and liquefying the processing fluid output as a gas from the fluid supply source 700 and then storing it. The processing fluid output as a liquid from the purification unit 710 is then heated in the supply unit 720 to become supercritical and introduced into the processing chamber 412.

[0065] Several filters are placed along the flow path of this processed fluid. Specifically, a filter 711 is inserted into the piping 731 through which the processed fluid flows as a gas. Since the processed fluid is always a gas and its pressure is regulated by a pressure regulating valve V70, a filter unit suitable for handling gas at that pressure can be applied to the filter 711. For example, a filter unit with a structure in which a filter element is housed in a resin housing can be used.

[0066] On the other hand, the upstream filters of the supply unit 720, namely filters 721 and 722, are interposed in the piping 741 through which the processing fluid flows as a high-pressure liquid. The processing fluid flowing through piping 741 is always a liquid, and its pressure is stable. Therefore, a filter unit suitable for processing such a liquid can be used, for example, a filter unit with a structure in which the filter element is housed in a metal housing. In this case, the filter units used for the two filters 721 and 722 are assumed to have the same structure.

[0067] Filters 721 and 722 are connected in parallel along the flow path. In other words, filter units of the same structure are arranged in parallel along the liquid flow path. The main reasons for this are as follows: The first reason is to ensure a sufficiently large flow rate of the processed fluid in this section. The second reason is to suppress the temperature drop of the filter units.

[0068] Let me explain the first reason in more detail. The fluid pathway for the processing fluid branches into two downstream of filters 721 and 722, supplying the processing fluid to the upper space of the substrate S and the lower space of the support tray 415 within the processing space SP, respectively. Since the processing fluid supplied to both of these areas is carried through piping 741, the filter that receives it needs to have a large capacity.

[0069] In this sense, it would be sufficient to use a single, larger-capacity filter unit. However, filter units with excellent particle removal performance are often small, and simply using a large-capacity filter unit will not provide the necessary filtering performance. Therefore, by connecting several small, high-performance filter units in parallel, it is possible to achieve both high filtering performance and large capacity.

[0070] Three or more filter units may be connected in parallel. However, since increasing the number of connecting pipes, fittings, and other components may actually increase the potential for contamination, it is preferable to determine the number of filter units to install while considering the balance between performance and capacity.

[0071] Next, let me explain the second reason in more detail. The filter in this position handles liquids, and since liquid-phase fluids have higher viscosity than other states, the pressure loss in the filter is relatively large. As a result, the rapid pressure drop of the processed fluid passing through the filter causes a decrease in temperature, which cools the filter unit. Experiments by the inventors of this application have confirmed that condensation actually occurs in the housing. In particular, filter units with metal housings may experience corrosion or rust due to condensation.

[0072] A more serious problem is that the processing fluid itself cools and partially solidifies within the filter unit, causing the filter to clog. This reduces the flow rate of the processing fluid and further increases pressure loss, making it difficult to clear the clog once it occurs. Furthermore, fluctuations in the flow rate of the processing fluid have a significant impact on the processing in the processing chamber 412.

[0073] By connecting filter units in parallel and distributing the flow of the processed fluid, pressure loss in each filter unit is reduced, and the temperature drop becomes more gradual. This significantly reduces the risk of clogging caused by condensation on the housing and solidification of the processed fluid within the filter units.

[0074] The filters 727 and 728, positioned directly before the processing chamber 412 in the flow path, ultimately determine the cleanliness of the processing fluid introduced into the processing space SP, and therefore require high particle removal performance. For this reason, a filter unit using a metal housing that is less likely to become a new source of contamination is suitable. In this case as well, the problem of temperature drop may occur, but unlike the filters 721 and 722 mentioned earlier, it is not a major problem. This is because the fluid being handled is a low-viscosity supercritical fluid, resulting in low pressure loss, and because the processing fluid is heated by heaters 725 and 726, there is little risk of the temperature dropping to a level low enough to cause condensation or solidification of the processing fluid.

[0075] Furthermore, since the processing fluid is pre-distributed into two flow paths, it is not necessarily required to connect filter units in parallel in each flow path. In addition, for filters 727 and 728, high-performance, compact filter units may be used in parallel connection if performance is a priority.

[0076] While filter units designed for processing supercritical fluids are not generally readily available, it is possible to treat supercritical fluids as liquids with extremely low viscosity and repurpose filters designed for such liquids. For example, filters 727 and 728 can be constructed using filter units with the same structure as filters 721 and 722. This approach offers cost advantages by standardizing the filter body and replacement parts.

[0077] The processing fluid flows as a liquid through the filter 716 located downstream of the pressurizing pump 715. Since this processing fluid is relatively large in volume and experiences significant pressure changes, it is desirable to use a filter unit suitable for such applications. For example, a filter unit with a metal housing containing the filter element can be used. While multiple filter units may be connected in parallel, high particle removal performance is not necessarily required for the filter at this location; therefore, a single filter unit with a large capacity but somewhat inferior performance can also be used.

[0078] Thus, several filters are placed in the fluid path, each of which is selected appropriately according to the state of the fluid being handled and the required performance.

[0079] Next, the detailed structure of the fluid recovery unit 455 will be described. The fluid supply unit 455 mainly consists of a high-pressure exhaust tank 505, a low-pressure exhaust tank 508, and a group of pipes 530 connecting them. These operate in response to control commands from the supercritical processing control unit 97.

[0080] A pipe 531, which forms part of a piping group 530, is connected to the upper part of the processing chamber 412. On the other hand, a pipe 532 is connected to the lower part of the processing chamber 412. These pipes 531 and 532 discharge the processing fluid that has flowed above and below the support tray 415 in the internal space SP from the processing chamber 412 to the outside. A pressure gauge 503 is provided on pipe 531.

[0081] In piping 531, a flow meter 501 and a valve V51 (which acts as an on-off valve) are inserted in that order along the direction of flow of the processed fluid. On the other hand, in piping 532, a flow meter 502 and a valve V52 (which acts as an on-off valve) are inserted in that order along the direction of flow of the processed fluid. At the output side of valves V51 and V52, piping 531 and 532 merge. In piping 533 after the merger, a pressure regulating valve V53 and a valve V54 (which acts as an on-off valve) are inserted.

[0082] The piping 533 is connected to the high-pressure exhaust tank 505, and the processed fluid discharged from the processing chamber 412 is contained in the high-pressure exhaust tank 505 via the piping 533. The high-pressure exhaust tank 505 is equipped with a heater 506 to maintain the temperature of the processed fluid stored inside at an appropriate level.

[0083] A pipe 544 is connected to the top of the high-pressure exhaust tank 505. A valve V55 (an on / off valve), a valve V56 (a pressure regulating valve), and a heater 507 are interposed in the pipe 544, and the pipe 544 is finally connected to the low-pressure exhaust tank 508. Thus, the processed fluid, as a gas with appropriately adjusted pressure and temperature, flows into the low-pressure exhaust tank 508. The processed fluid in the low-pressure exhaust tank 508 is finally recovered via a pipe 545 by an external recovery device (not shown). A pressure sensor 510 is provided in the pipe 545 for detecting the pressure of the gas being discharged to the outside.

[0084] Furthermore, piping 546 is connected to the lower part of the high-pressure exhaust tank 505, while piping 547 is connected to the lower part of the low-pressure exhaust tank 508. These pipes merge to form piping 548, to which valve V57, an on / off valve, is connected. When valve V57 is opened, the liquid treatment fluid stored in the high-pressure exhaust tank 505 and the low-pressure exhaust tank 508 is discharged to an external recovery device.

[0085] The operation of the supercritical processing apparatus 4 configured as described above will be explained with reference to Figures 6 and 7. The supercritical processing apparatus 4 performs a process to dry the substrate S after wet processing using a processing fluid in a supercritical state, that is, a supercritical drying process. This process is realized by the CPU 91 of the control unit 9 executing a pre-prepared control program to control each part of the apparatus.

[0086] Figure 6 is a flowchart showing the process performed by the supercritical fluid processing apparatus. Figure 7 is a diagram showing the pressure changes in the processing chamber and storage tank during this process. The fluid supply unit 457 supplies gaseous and liquid processing fluids from the storage tank 717, which stores the processing fluid, to the processing chamber 412. Therefore, the pressure in the processing space SP of the processing chamber 412 (hereinafter referred to as "chamber pressure") and the pressure in the internal space of the storage tank 717 (hereinafter referred to as "tank pressure") change as the process progresses.

[0087] First, the substrate transfer device 3 and the supercritical processing device 4 work together to load the substrate S into the processing chamber 412 (step S101). Specifically, the transfer robot 30 of the substrate transfer device 3 holds the substrate S after the liquid film formation process has been completed in the wet processing device 2, and places the substrate S on the support tray 415, which has been pulled out of the processing chamber 412. More precisely, the substrate S is first transferred from the hand 31 of the transfer robot 30 to the lift pin 437 of the supercritical processing device 4, and then from the lift pin 437 to the support tray 415.

[0088] The support tray 415 on which the substrate S is placed is housed in the processing chamber 412. The lid member 413 closes the opening 421 of the processing chamber 412, thereby sealing the processing space SP inside the processing chamber 412. This completes the loading of the substrate S. Since the processing chamber 412 is opened to the atmosphere for loading the substrate S, the internal pressure of the processing chamber 412 is atmospheric pressure Pa in the initial state, as shown in the upper part of Figure 7.

[0089] While the substrate S is being transferred in this manner, the fluid supply unit 457 performs a predetermined standby operation (step S102). As will be described in detail later, the standby operation is an operation in the fluid supply unit 457 to prepare the required amount of processing fluid at a temperature and pressure suitable for use in subsequent processing. As will be described later, in this embodiment, gaseous carbon dioxide at a temperature of 20°C and a pressure of 6 MPa, and supercritical carbon dioxide heated from a temperature of 20°C and a pressure of 11 MPa are used for processing.

[0090] After the substrate S is brought in, the introduction of the gaseous processing fluid is started from the fluid supply unit 457 (step S103; time T1), which causes the chamber pressure to gradually rise. When the chamber pressure rises to a predetermined first pressure P1 (step S104; time T2), a supercritical processing fluid is supplied from the fluid supply unit 457 to the processing chamber 412 instead of the gas (step S105; time T3).

[0091] As a result, the processing space SP of the processing chamber 412 is filled with a supercritical processing fluid, and the chamber pressure is maintained at a constant second pressure P2 which is greater than the first pressure P1 and the critical pressure of the processing fluid (times T4-T5). Meanwhile, any liquid remaining on the substrate S is replaced by the supercritical processing fluid, dissolves into the processing fluid, and is removed from the surface of the substrate S.

[0092] Once the chamber pressure has been maintained at approximately pressure P2 for a predetermined period of time (step S106), the discharge of the processing fluid from the processing chamber 412 begins (step S107; time T5), thereby reducing the pressure in the processing space SP. After time T7, when the chamber pressure has dropped to near atmospheric pressure Pa, the substrate S is unloaded by the transport robot 30 (step S108), completing the processing for one substrate S. If there is another substrate to be processed, the process returns to step S101 (step S109), and the above process is repeated.

[0093] As shown in the lower part of Figure 7, the internal pressure of the storage tank 717 gradually decreases as the processing fluid stored in the tank is consumed. To restore this pressure, a standby operation is performed to replenish the pressurized processing fluid in the storage tank 717 (step S111). The standby operation can be performed after time T6, when the supply of processing fluid from the storage tank 717 to the processing chamber 412 is stopped. Therefore, as shown in Figure 7, it is possible to start the standby operation while the pressure inside the processing chamber 412 is being reduced.

[0094] When performing supercritical drying on the substrate S, it is desirable to raise the tank pressure to approximately the same as or slightly higher than the first pressure P1 during standby operation, so that the chamber pressure can be raised to the first pressure P1 in step S103 of the process.

[0095] Specifically, the processing fluid output from the fluid supply source 700 is pressurized by the pressurizing pump 715 and then introduced into the storage tank 717, thereby raising the internal pressure of the tank to a target value. For this purpose, valves V71, V72, and V74 are opened, while valves V73, V75, and V76 are closed.

[0096] Therefore, the processing fluid, output from the fluid supply source 700 and whose pressure is adjusted by the valve V70, is pressurized to a predetermined pressure by the pressurizing pump 715 and stored in the storage tank 717. The amount of liquid in the tank is monitored by the level sensor 718, and the supply of processing fluid continues until a predetermined amount of liquid at a predetermined pressure is accumulated. In addition, the temperature of the processing fluid in the tank is adjusted by the heater 719.

[0097] Thus, during the waiting period when no processing fluid is supplied from the storage tank 717 to the processing chamber 412 (before time T1 and after time T6 in Figure 7), a process is performed as a standby operation to maintain the liquid volume, pressure, and temperature in the tank at predetermined values. The target pressure is the first pressure P1 or slightly higher, which in this embodiment is 6 MPa. The target temperature in this embodiment is 20°C. The target liquid volume is set to an amount sufficient to adequately supply the processing fluid to the processing chamber 412 in the supercritical drying process described above.

[0098] As described above, in the first embodiment of the substrate processing apparatus according to this invention, filters optimized according to the state of the processing fluid at each position are placed at multiple locations along the flow path of the processing fluid, which is output as a gas, liquefied, and finally introduced into the processing chamber in a supercritical state by heating, thereby purifying the processing fluid. In other words, each filter is placed at a location in the flow path of the processing fluid where the circulating processing fluid is a gas, a liquid, and a supercritical state, respectively.

[0099] This allows for the placement of filters optimized according to the state and purpose of the processing fluid. As a result, it becomes possible to perform good processing on the substrate using an effectively purified processing fluid. Furthermore, the substances contained in the processing fluid that can contaminate the substrate may include those that are easily removed when the processing fluid is in a gaseous state, those that are easily removed when it is in a liquid state, and those that are easily removed when it is in a supercritical state. By placing filters in each flow path of the processing fluid in each phase, these contaminants can be effectively removed.

[0100] As described above, in the above-described embodiment, the supercritical fluid processing apparatus 4 corresponds to the "substrate processing apparatus" of the present invention, and the processing chamber 412 having a processing space SP as an "internal space" functions as the "processing chamber" of the present invention. Furthermore, the fluid supply unit 457 has the function of a "supply unit" of the present invention.

[0101] Furthermore, in the above embodiment, the piping groups 730 and 740 and the valves arranged on those piping function as a whole as the "flow path forming section" of the present invention. Heaters 725 and 726 function as the "heating section" of the present invention. Filters 721 and 722 each correspond to the "filter unit" of the present invention, and together they constitute the "first filter section" of the present invention. On the other hand, filters 727 and 728 each correspond to the "second filter section" of the present invention individually. And the piping 747 and 748 on which these are arranged correspond to the "branching section" of the present invention.

[0102] Furthermore, in the above embodiment, the fluid supply source 700 functions as the "gas supply source" of the present invention, and the purification unit 710 functions as the "liquefaction mechanism" of the present invention. In addition, the filter 712 functions as the "third filter section" of the present invention.

[0103] <Second Embodiment> Figure 8 shows a second embodiment of the substrate processing apparatus. The substrate processing apparatus of the second embodiment and each embodiment described later has a partially modified configuration of the supply unit 720 in the first embodiment, but the other configurations are the same as those of the first embodiment. Therefore, in order to clearly show the changes from the supply unit 720, configurations whose structure and function are the same as those of the first embodiment will be omitted from description or will be given the same reference numerals and detailed explanations will be omitted.

[0104] As shown in Figure 8, in the supply unit 720A of the second embodiment, liquid filters 721A and 722A are provided in the piping after it branches off from piping 741. That is, piping 743 and 744, which were provided in the first embodiment, are removed, and two pipes 747A and 748A branch directly off from piping 741. One of the pipes, 747A, is equipped with a liquid filter 721A, a flow meter 723, a heater 725, a valve V78, and a filter 727 for supercritical fluid.

[0105] The filter 721A may be installed upstream of the flow meter 723, as shown by the solid line in the figure, or downstream of the flow meter 723, as shown by the dotted line. The figure shows that the filter 721A is installed at one of these locations, but does not show that it is installed at both locations.

[0106] In addition, the other pipe 748A is equipped with a liquid filter 722A, a flow meter 724, a heater 726, a valve V79, and a filter 728 for supercritical fluid. Here as well, the filter 722A can be positioned either before or after the flow meter 723.

[0107] With this configuration, the pipes 743 and 744 can be omitted, thereby reducing the number of structures that could be sources of contamination. In this case, the flow rate of the processed fluid in each filter 721A and 722A is about the same as that of filters 721 and 722 which were connected in parallel, so it is possible to use equivalent filter units individually.

[0108] <Third Embodiment> Figure 9 shows a third embodiment of the substrate processing apparatus. The difference between 720B in this embodiment and the first embodiment is that the filters for the supercritical fluid are connected in series. That is, another filter 727B is placed upstream or downstream of filter 727. Similarly, another filter 728B is placed upstream or downstream of filter 728. The two filters 727 and 727B connected in series may have the same structure, or they may have different structures to be used depending on the purpose. The same applies to the other two filters 728 and 728B.

[0109] While such series connections of filters can improve particle removal performance, they increase pressure loss in the flow path. Such configurations may be acceptable in the flow path of supercritical fluids with extremely low viscosity.

[0110] <Fourth Embodiment> Figure 10 shows a fourth embodiment of the substrate processing apparatus. The difference between 720C in this embodiment and the first embodiment is that the filters for the supercritical fluid are connected in parallel. Specifically, filter 727C is connected in parallel to filter 727, which is placed in the flow path of the supercritical fluid, and filter 728C is connected in parallel to filter 728. This configuration was also mentioned in the description of the first embodiment, but by adopting this parallel connection, it becomes possible to apply high-performance filter units even with small capacities. This makes it possible to further improve the cleanliness of the processing fluid introduced into the processing chamber 412.

[0111] <Other variations> It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the fluid supply unit 457 of the above embodiment includes components that are generally provided in the flow path of the processed fluid, such as a flow meter, but are not directly related to the present invention. The present invention can still be established even if these components are omitted.

[0112] Furthermore, in the above embodiment, for example, 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 separately for the upper and lower sides of the support tray 415, respectively. However, this is not a mandatory requirement.

[0113] Furthermore, in the above embodiment, since the fluid supply source 700 outputs the processed fluid as a gas, a gas filter 712 is inserted into the piping 731 which serves as the gas flow path. If the fluid supply source outputs the processed fluid as a liquid, this filter may be changed to one for liquids or omitted altogether.

[0114] Furthermore, as shown by the dotted line in Figure 5, if a pipe 737 is provided that connects directly from the fluid supply source 700 to the valve V76, it is desirable that a gas filter be inserted into this pipe 737.

[0115] Furthermore, the various chemical substances and numerical values ​​used in the processing of the above embodiments are merely examples, and various other substances can be used as substitutes, as long as they are consistent with the technical concept of the present invention as described above.

[0116] As described above with specific embodiments as examples, in the substrate processing apparatus according to the present invention, for example, the flow path may branch into a plurality of branch paths, each of which may be connected to a processing chamber, and a heating unit and a second filter unit may be individually provided for each of the branch paths. With such a configuration, it is possible to supply processing fluid to the processing chamber from multiple locations, and by arranging a heating unit and a second filter unit in each of these flow paths, the temperature and cleanliness of the supplied processing fluid can be properly maintained.

[0117] In this case, the flow path may be configured to branch, for example, on the output side of the first filter section, or a first filter section may be provided individually for each branch path. In either configuration, the processed fluid that has passed through the first filter section as a liquid can be supplied to the processing chamber as a supercritical fluid.

[0118] For example, the first filter section may have a configuration in which multiple filter units of the same structure are connected in parallel to each other. There is a trade-off relationship between filter performance and pressure loss, and pressure loss tends to be particularly large in the first filter section that handles liquids. In addition, it is not easy to prepare high-performance, high-capacity filters. Therefore, by connecting multiple filters with the required performance in parallel, it is possible to increase capacity without reducing performance.

[0119] Furthermore, a large pressure loss can lead to a decrease in the pressure of the processed fluid, which can cause a problem due to the resulting temperature drop of the processed fluid. In particular, if the filter unit has a structure in which the filter element is housed in a metal housing, condensation caused by the temperature drop of the processed fluid can cause rust and corrosion of the housing. By distributing the processed fluid through parallel connection of filters, it is possible to mitigate such temperature drops.

[0120] Furthermore, for example, the second filter section may have a filter unit with the same structure as the first filter unit. The fluid handled by the second filter section is in a supercritical state, but it cannot be said that there is a sufficient supply of filter units optimized for this on the market. If the supercritical fluid is considered to be a liquid with extremely low viscosity, then a filter unit for such a liquid can be applied. In that case, for example, it becomes possible to use a filter unit with the same structure as the one used to handle the liquid in the first filter section, thereby achieving cost benefits through the commonality of parts.

[0121] Furthermore, in this invention, for example, the supply unit may include a gas supply source that outputs a gaseous processing fluid, and a liquefaction mechanism that pressurizes or cools the processing fluid output from the gas supply source to liquefy it, wherein the liquefaction mechanism is configured to output a liquid processing fluid to a flow path. With such a configuration, it becomes possible to perform processing using, for example, a gas cylinder available on the market as the gas supply source. This makes it possible to reduce the processing cost of substrates.

[0122] In this case, it is desirable that the gas supply source and the liquefaction mechanism be connected via a third filter section that filters the gaseous fluid being processed. This allows for the removal of contaminants such as particles contained in the gas before liquefaction. Furthermore, it is possible to lower the required level of cleanliness for the gas supply source, thereby reducing its procurement costs. [Industrial applicability]

[0123] This invention can be applied to all techniques for processing substrates using a supercritical processing fluid in a processing chamber. [Explanation of Symbols]

[0124] 4. Supercritical fluid processing equipment (substrate processing equipment) 412 Processing Chamber 457 Fluid supply section (supply section) 700 Fluid supply source (gas supply source) 710 Purification Unit (Liquefaction Mechanism) 712 Filter (Third Filter Section) 715 Pressure pump (pressurizing section) 721,722 Filter (Filter unit, first filter section) 725,726 Heater (heating section) 727,728 Filter (Second Filter Section) 730,740 Piping group (flow channel forming section) 747,748 Piping (branch lines) S substrate SP processing space (internal space)

Claims

1. In a substrate processing apparatus that processes a substrate using a processing fluid in a supercritical state, A processing chamber having an internal space capable of accommodating the aforementioned substrate, A supply unit capable of supplying the aforementioned processing fluid as a liquid, A heating unit that heats the liquid processing fluid supplied from the supply unit to a temperature above the critical temperature of the processing fluid to transition it to a supercritical state, A flow path forming unit that forms a flow path for the processing fluid from the supply unit through the heating unit to the processing chamber, A first filter unit is inserted in the flow path between the supply unit and the heating unit to filter the liquid processing fluid, A second filter unit is inserted in the flow path between the heating unit and the processing chamber to filter the processing fluid in a supercritical state. Equipped with, The first filter section is a substrate processing apparatus having a plurality of filter units of the same structure connected in parallel to one another.

2. The substrate processing apparatus according to claim 1, wherein the flow path branches into a plurality of branch paths, each of which is connected to the processing chamber, and the heating unit and the second filter unit are individually provided for each of the branch paths.

3. The substrate processing apparatus according to claim 2, wherein the flow path is branched on the output side of the first filter section.

4. The substrate processing apparatus according to claim 2, wherein the first filter unit is provided individually for each of the branch paths.

5. The substrate processing apparatus according to claim 1, wherein the second filter section has a plurality of filter units connected in series with respect to each other.

6. The substrate processing apparatus according to claim 1, wherein the filter unit has a structure in which a filter element is housed in a metal housing.

7. The substrate processing apparatus according to claim 1, wherein the second filter section has a filter unit having the same structure as the filter unit.

8. The supply unit comprises a gas supply source that outputs the gaseous processing fluid, and a liquefaction mechanism that pressurizes or cools the processing fluid output from the gas supply source to liquefy it. The substrate processing apparatus according to any one of claims 1 to 7, wherein the liquefaction mechanism outputs the liquid processing fluid to the flow path.

9. The substrate processing apparatus according to claim 8, wherein the gas supply source and the liquefaction mechanism are connected via a third filter section that filters the gaseous processing fluid.

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