Substrate processing device and substrate processing method

Abstract

To suppress the variation in substrate processing quality due to clogging of a filter provided 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 accommodates a substrate, a supply part that supplies process fluid to the processing chamber, a discharge part that discharges the process fluid from the processing chamber, a control part that controls the supply part and the discharge part and changes the pressure in the internal space in accordance with a predetermined process recipe, a filter part that is provided in an introduction flow channel of the process fluid from the supply part to the process chamber and filters the process fluid, a first detection part that is provided between the filter part and the supply part in the introduction flow channel and detects the flow rate of the process fluid flowing in the introduction flow channel, and a second detection part that is provided in a discharge flow channel of the process fluid from the processing chamber to the discharge part and detects the flow rate of the process fluid flowing in the discharge flow channel.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technique for placing a substrate in a processing chamber and processing it with a processing fluid in a supercritical state. [Background technology]

[0002] Processing processes for various substrates, such as semiconductor substrates and glass substrates for display devices, include treating the surface of the substrate with various processing fluids. Wet processing using liquids such as chemicals and rinses as processing fluids has been widely used. In recent years, processing using processing fluids in a supercritical state has also been put to practical use to dry substrates after such wet processing. This is particularly useful in drying substrates having a patterned surface on which a fine pattern is formed. This is because processing fluids in a supercritical state have a lower surface tension than liquids and have the property of penetrating deep into the gaps in the pattern. Using such processing fluids enables efficient drying processing. It is also possible to reduce the risk of pattern collapse due to surface tension during drying.

[0003] For example, in the substrate processing apparatus described in Patent Document 1, a processing fluid in a supercritical state is introduced into the internal space of a processing chamber containing a substrate, and after the pressure in the internal space is maintained constant for a predetermined time, the processing fluid is discharged. A filter is inserted in the flow path that supplies the processing fluid to the internal space to filter the processing fluid and remove contaminants such as particles that may be contained therein. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-036123 Summary of the Invention [Problem to be solved by the invention]

[0005] In a filter that filters high-pressure fluid, the flow rate of the fluid passing through it varies depending on the magnitude of the pressure loss in the filter. Furthermore, the filter gradually becomes clogged with foreign matter such as particles, which causes the magnitude of the pressure loss to change over time. As a result, the amount of processing fluid passing through the filter and flowing into the processing chamber fluctuates over time. This means that the quality of processing for substrates fluctuates. This is because, in substrate processing using supercritical fluids, fluctuations in fluid density significantly affect processing quality. In particular, when the apparatus is used continuously over a long period of time, such as when processing multiple substrates sequentially, the processing quality for each substrate becomes unstable.

[0006] The above-mentioned prior art does not address this issue, and its control is based on the premise that the flow rate of the processing fluid is determined by the valve opening. In reality, as mentioned above, the flow rate can change over time due to filter clogging, and so it is necessary to address this issue.

[0007] As described above, supercritical processing technology, which places a filter in the flow path through which high-pressure fluid flows, involves an unstable factor of flow rate fluctuations due to clogging, and there is still room for improvement, particularly from the perspective of long-term stability of processing quality.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a technology for processing a substrate with a supercritical processing fluid, which can suppress fluctuations in the processing quality of the substrate caused by clogging of a filter provided in the flow path of the processing fluid. [Means for solving the problem]

[0009] One aspect of the present 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 supply unit for supplying the processing fluid to the processing chamber; an exhaust unit for exhausting the processing fluid from the processing chamber; a control unit for controlling the supply unit and the exhaust unit to change the pressure of the internal space in accordance with a predetermined processing recipe; a filter unit provided in an inlet flow path of the processing fluid from the supply unit to the processing chamber and filtering the processing fluid; a first detection unit provided in the inlet flow path between the supply unit and the filter unit and detecting the flow rate of the processing fluid flowing through the inlet flow path; and a second detection unit provided in an exhaust flow path of the processing fluid from the processing chamber to the exhaust unit and detecting the flow rate of the processing fluid flowing through the exhaust flow path.

[0010] Another aspect of the present invention is a substrate processing method for processing a substrate with a processing fluid in a supercritical state, comprising: a first step of accommodating the substrate in an internal space of a processing chamber; a second step of supplying the processing fluid to the internal space and discharging the processing fluid from the internal space to fill the internal space with the processing fluid in a supercritical state; and a third step of discharging the processing fluid from the internal space. Here, in the second step, the processing fluid filtered by a filter unit is supplied to the internal space, and the supply amount of the processing fluid flowing into the filter unit and the discharge amount of the processing fluid discharged from the internal space are detected, while the supply amount and the discharge amount of the processing fluid are adjusted so that the pressure in the internal space changes in accordance with a predetermined processing recipe.

[0011] In the invention configured as described above, the flow rate of the processing fluid is detected along the flow path of the processing fluid that passes through the filter unit and reaches the processing chamber. The flow rate of the processing fluid discharged from the processing chamber is also detected. That is, in this invention, the amount of processing fluid actually flowing into the processing chamber and the amount of processing fluid actually flowing out of the processing chamber are detected. While the inflow rate of the processing fluid is preferably measured immediately before the processing chamber, it is detected upstream of the filter unit in the flow direction of the processing fluid to maintain the purity of the inflowing processing fluid.

[0012] As described above, the flow rate of the processing fluid passing through the filter section fluctuates over time due to an increase in pressure loss caused by clogging, etc. In response to this problem, the present invention detects both the inflow and outflow rates of the processing fluid into the processing chamber, so that even if the flow rate fluctuates due to clogging, etc., this fact can be detected. In addition, the balance between the inflow and outflow rates can also be determined.

[0013] Substrate processing in a processing chamber is performed by controlling the pressure within the processing chamber according to a predetermined processing recipe. However, controlling the pressure alone does not guarantee that the density of the processing fluid within the processing chamber will be maintained appropriately. In contrast, the present invention can grasp not only the pressure but also the amount of processing fluid actually flowing into and out of the processing chamber, making it possible to appropriately control the density of the processing fluid within the processing chamber by combining pressure control.

[0014] The detection results can be used in various ways. For example, if the pressure loss in the flow path increases due to clogging of the filter, this is expected to manifest as a decrease in the amount of processing fluid flowing into the processing chamber. Therefore, in such a case, the inflow rate can be restored by, for example, increasing the pressure on the processing fluid upstream of the filter or reducing the amount of processing fluid discharged. [Effects of the Invention]

[0015] As described above, according to the present invention, the flow rate of the processing fluid flowing into the processing chamber is detected in the flow path that supplies the processing fluid to the processing chamber, and the flow rate of the processing fluid flowing out of the processing chamber is also detected. Therefore, it is possible to appropriately respond to fluctuations in the inflow rate of the processing fluid caused by clogging of the filter, etc., and thereby stabilize the processing quality. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing a schematic configuration of a substrate processing system equipped with an embodiment of a substrate processing apparatus according to the present invention; [Figure 2] 1 is a side view showing the overall configuration of a wet treatment apparatus. [Figure 3] 4A and 4B are diagrams for explaining the operation of the wet treatment apparatus. [Figure 4] FIG. 1 is a side view showing the configuration of a supercritical processing apparatus. [Figure 5] FIG. 2 is a diagram showing details of supply and discharge paths of processing fluids. [Figure 6] 1 is a flowchart showing a process executed by a supercritical processing apparatus. [Figure 7] 1A and 1B are diagrams showing pressure changes in a processing chamber and a storage tank. [Figure 8] 10 is a flowchart showing an outline of supply and discharge control of a processing fluid. [Figure 9] 10 is a flowchart showing a modified example of the supply and discharge control of the processing fluid. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1 is a diagram showing the schematic configuration of a substrate processing system equipped with one embodiment of a substrate processing apparatus according to the present invention. This substrate processing system 1 is a processing system for wet-processing various substrates, such as semiconductor wafers, by supplying a processing liquid to the upper surface of the substrate and then drying the substrate, and has a system configuration suitable for carrying out a substrate processing method according to the present invention. The substrate processing system 1 mainly comprises a wet-processing apparatus 2, a substrate transfer apparatus 3, a supercritical processing apparatus 4, and a control apparatus 9.

[0018] The wet processing device 2 receives a substrate to be processed and performs a predetermined wet processing. The type of processing is not particularly limited. Wet processing includes development processing, cleaning processing, etc., and after the development processing, etc., a puddle of an organic solvent such as IPA liquid is created on the pattern-forming surface of the substrate. The substrate transport device 3 transports the substrate from the wet processing device 2 while maintaining the puddle state, and transports it into the supercritical processing device 4. The supercritical processing device 4 corresponds to the substrate processing device according to the present invention, and performs a drying process (supercritical drying process) on the transported substrate using a processing fluid in a supercritical state. These are installed in a clean room. Therefore, the substrate transport device 3 transports the substrate in the air atmosphere and at atmospheric pressure.

[0019] The control device 9 controls the operation of each of these devices to achieve predetermined processing. For this purpose, the control device 9 is equipped with 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 the control programs executed by the CPU 91. The interface 94 exchanges information with users and external devices. The operations of the devices described below are achieved by the CPU 91 executing control programs written in advance in the storage 93 and causing each part of the device to perform a predetermined operation.

[0020] When the CPU 91 executes a predetermined control program, functional blocks such as a wet processing control unit 95 that controls the operation of the wet processing apparatus 2, a transport control unit 96 that controls the operation of the substrate transport apparatus 3, and a supercritical processing control unit 97 that controls the operation of the supercritical processing apparatus 4 are realized in software in the control device 9. Note that at least a part of each of these functional blocks may be configured by dedicated hardware.

[0021] The "substrate" in this embodiment can be any of a variety of substrates, including semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, and substrates for magneto-optical disks. The following description will be given with reference to the drawings, taking as an example a substrate processing apparatus used primarily for processing disc-shaped semiconductor wafers. However, the present invention can be similarly applied to processing the various substrates exemplified above. Various substrate shapes can also be used.

[0022] In the following description, a substrate having a pattern formed on only one main surface will be used as an example. Here, the main surface on which a pattern or the like is formed will be referred to as the "front surface," and the opposite main surface on which no pattern is formed will be referred to as the "rear surface." Furthermore, the main surface of the substrate facing downward will be referred to as the "bottom surface," and the main surface of the substrate facing upward will be referred to as the "top surface." In the following description, the top surface will be referred to as the front surface.

[0023] 2 and 3 are diagrams showing an example of the configuration 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 S by supplying a processing liquid to the upper surface of the substrate. The operation of the wet-processing apparatus 2 is controlled by a wet-processing control unit 95 of the control device 9.

[0024] The wet processing apparatus 2 supplies a processing liquid to the surface (pattern formation surface) Sa of the substrate S to perform wet processing such as surface processing and cleaning of the substrate S. For this purpose, the wet processing apparatus 2 includes a substrate holding unit 21, a splash guard 22, and processing liquid supply units 23 and 24 inside a processing chamber 200. The operations of these units are controlled by a wet processing control unit 95 provided in the control device 9. The substrate holding unit 21 has a disk-shaped spin chuck 211 having approximately the same diameter as the substrate S, and a plurality of chuck pins 212 are provided on the periphery of the spin chuck 211. The chuck pins 212 abut against the periphery of the substrate S to support the substrate S, allowing the spin chuck 211 to hold the substrate S in a horizontal position while spaced apart from its upper surface.

[0025] The spin chuck 211 is supported by a rotation support shaft 213 extending downward from the center of its lower surface so that its upper surface is horizontal. The rotation support shaft 213 is rotatably supported by a rotation mechanism 214 attached to the bottom of the processing chamber 200. The rotation mechanism 214 has a built-in rotation motor (not shown), and when the rotation motor rotates in response to a control command from the control device 9, the spin chuck 211 directly connected to the rotation support shaft 213 rotates around the rotation axis AX indicated by the dashed dotted line. In FIG. 2, the up-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.

[0026] A splash guard 22 is provided to surround the substrate holding part 21 from the side. The splash guard 22 has a generally cylindrical cup 221 provided to cover the peripheral part of the spin chuck 211, and a liquid receiving part 222 provided below the outer periphery of the cup 221. The cup 221 moves up and down in response to a control command from the control device 9. The cup 221 moves up and down between a lower position where the upper end of the cup 221 is lowered below the peripheral part of the substrate S held by the spin chuck 211 as shown in FIG. 2, and an upper position where the upper end of the cup 221 is located above the peripheral part of the substrate S as shown in FIG. 3.

[0027] 2, when the cup 221 is in the lower position, 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, the substrate S is loaded onto or unloaded from the spin chuck 211.

[0028] 3, when the cup 221 is in the upper position, it surrounds the peripheral edge of the substrate S held by the spin chuck 211. This prevents the processing liquid shaken off from the peripheral edge of the substrate S during liquid supply, which will be described later, from scattering inside the chamber 200, making it possible to reliably collect the processing liquid. That is, droplets of the processing liquid shaken off from the peripheral edge of the substrate S as the substrate S rotates adhere to the inner wall of the cup 221 and flow downward, and are collected by the liquid receiving portion 222 arranged below the cup 221. In order to collect multiple processing liquids individually, multiple stages of cups may be provided concentrically.

[0029] 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 pivotal support shaft 232 that is rotatably provided on a base 231 fixed to the processing chamber 200. The pivotal support shaft 232 rotates in response to a control command from the control device 9, causing the arm 233 to swing, and the nozzle 234 at the tip of the arm 233 moves between a retracted position retracted laterally from above the substrate S as shown in FIG. 2 and a processing position above the substrate S as shown in FIG.

[0030] The nozzle 234 is connected to a processing liquid supply source 238, and when an appropriate processing liquid is delivered from the processing liquid supply source 238, the processing liquid is ejected from the nozzle 234 toward the substrate S. As shown in FIG. 2B , the spin chuck 211 rotates at a relatively slow speed to rotate the substrate S, and a processing liquid L1 is supplied from the nozzle 234 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 having various functions, such as a developer, an etching liquid, a cleaning liquid, or a rinse liquid, and the composition thereof is optional. Furthermore, processing may be performed using a combination of multiple types of processing liquids.

[0031] The other processing liquid supply unit 24 also has a configuration corresponding to that of the above-described first processing liquid supply unit 23. 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 corresponding to those in 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 the processing liquid to the surface Sa of the substrate S.

[0032] In this embodiment, the second processing liquid supply unit 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 transported to the supercritical processing device 4 and subjected to supercritical drying processing, but in order to prevent the surface of the substrate S from being exposed and oxidized during transportation or the fine pattern formed on the surface from collapsing, the substrate S is transported with its surface covered with a puddle-shaped liquid film.

[0033] The liquid that constitutes the liquid film is a substance with a surface tension lower than that of water, which is the main component of the processing liquid used in the cleaning process, such as an organic solvent such as isopropyl alcohol (IPA) or acetone, which is supplied from an organic solvent supply source 248.

[0034] Here, two sets of processing liquid supply units are provided in the wet processing apparatus 2, but the number of processing liquid supply units provided, their structures, and functions are not limited to this. For example, only one set of processing liquid supply units may be provided, or three or more sets may be provided. Furthermore, one processing liquid supply unit may be provided with multiple nozzles. For example, multiple nozzles may be provided at the tip of one arm. Furthermore, in addition to the above-mentioned mode in which the processing liquid is discharged while the nozzle is positioned at a predetermined position, for example, a mode in which the nozzle discharges the processing liquid while scanning and moving along the surface Sa of the substrate S may also be included.

[0035] Returning to FIG. 1, the explanation will be continued. The substrate transfer device 3 is provided with a transfer robot 30 having a hand 31 attached to the tip of an extendable and rotatable arm. The hand 31 can support the substrate by partially abutting against the underside of the substrate, and as shown by the dotted line in FIG. 1, is movable toward and away from both the wet treatment device 2 and the supercritical treatment device 4. This allows substrates to be loaded into and unloaded from both the wet treatment device 2 and the supercritical treatment device 4. The operation of the transfer robot 30 is controlled by a transfer control unit 96 of the control device 9. There are many well-known technologies for this type of transfer robot, and any of these can be appropriately selected and used in this embodiment, so a detailed description will be omitted.

[0036] 4 is a side view showing the configuration of a supercritical processing apparatus. The supercritical processing apparatus 4 corresponds to a first embodiment of the substrate processing apparatus according to the present invention, and is an apparatus that performs a drying process using a processing fluid in a supercritical state on a substrate S after wet processing. More specifically, the supercritical processing apparatus 4 is an apparatus that receives the substrate S after wet processing, replaces the liquid remaining on the substrate S with the processing fluid in a supercritical state, and then discharges the processing fluid, thereby finally bringing the substrate S to a dry state.

[0037] The supercritical processing apparatus 4 includes a processing unit 41, a transfer unit 43, and a supply unit 45. The processing unit 41 is the main unit that performs the supercritical drying process. The transfer unit 43 receives the substrate S after wet processing that is transported by the substrate transport device 3 and transports 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 chemical substances, power, 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 unit 97.

[0038] The processing unit 41 has a structure in which a processing chamber 412 is mounted on a base 411. The processing chamber 412 is constructed by combining several metal blocks, and its interior is hollow, constituting a processing space SP. The substrate S to be processed is loaded into the processing space SP and undergoes processing. A slit-shaped opening 421 that is elongated in the X direction is formed on the (-Y) side surface of the processing chamber 412. The processing space SP communicates with the outside space via the opening 421. The cross-sectional shape of the processing space SP is approximately the same as the opening shape of the opening 421. In other words, 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 that extends in the Y direction.

[0039] A lid member 413 is provided on the (-Y) side surface 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 attached in a horizontal position to the (+Y) side surface of the lid member 413. The upper surface of the support tray 415 forms a support surface on which the substrate S can be placed. The lid member 413 is supported by a support mechanism (not shown) so as to be freely movable horizontally in the Y direction.

[0040] The lid member 413 can be moved toward and away from the processing chamber 412 by an advancing / retracting mechanism 453 provided in the supply unit 45. Specifically, the advancing / retracting mechanism 453 has a linear motion mechanism such as a linear motor, a linear motion guide, a ball screw mechanism, a solenoid, or an air cylinder. Such a linear motion mechanism moves the lid member 413 in the Y direction. The advancing / retracting mechanism 453 operates in response to a control command from the control device 9.

[0041] When the cover member 413 moves in the (-Y) direction to move away from the processing chamber 412 and the support tray 415 is pulled out from the processing space SP through the opening 421 as shown by the dotted line, access to the support tray 415 becomes possible. That is, it becomes possible to place the substrate S on the support tray 415 and to remove the substrate S placed on the support tray 415. On the other hand, when the cover member 413 moves in the (+Y) direction, the support tray 415 is accommodated in the processing space SP. When a 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.

[0042] The lid member 413 moves in the (+Y) direction to close the opening 421, thereby sealing the processing space SP. A seal member 422 is provided between the (+Y) side surface of the lid member 413 and the (-Y) side surface of the processing chamber 412, thereby maintaining the processing space SP in an airtight state. The seal member 422 is made of, for example, rubber. In addition, the lid member 413 is fixed to the processing chamber 412 by a locking mechanism (not shown). As described above, in this embodiment, the lid member 413 can be switched between a closed state (solid line) in which the lid member 413 closes the opening 421 to seal the processing space SP, and a separated state (dotted line) in which the lid member 413 is separated significantly from the opening 421 to allow the substrate S to be inserted or removed.

[0043] The processing space SP is kept airtight while the substrate S is processed within the processing space SP. In this embodiment, the fluid supply unit 457 in the supply unit 45 delivers a processing fluid, such as carbon dioxide, that is a substance suitable for supercritical processing. The processing fluid is then pressurized within the processing chamber 412 to bring it to a supercritical state. The processing fluid is supplied to the processing unit 41 in a gaseous or liquid state. Carbon dioxide is a chemical suitable for supercritical drying because it reaches a supercritical state at relatively low temperatures and pressures and has the property of dissolving organic solvents commonly used in substrate processing. The critical point at which carbon dioxide reaches a supercritical state is an atmospheric pressure (critical pressure) of 7.38 MPa and a temperature (critical temperature) of 31.1°C.

[0044] 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. In this manner, the substrate S is processed by the processing fluid in the processing chamber 412. The supply unit 45 is provided with a fluid recovery part 455, and the processed fluid is recovered by the fluid recovery part 455. The fluid supply part 457 and the fluid recovery part 455 are controlled by the supercritical processing control part 97.

[0045] The processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S supported thereon. That is, the processing space SP has a roughly rectangular cross-sectional shape that is wider than the width of the support tray 415 in the horizontal direction and greater than the combined height of the support tray 415 and the substrate S in the vertical direction, and a depth that can accommodate the support tray 415. In this way, the processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S. However, there is only a small gap between the support tray 415 and the substrate S and the inner wall surface of the processing space SP. Therefore, a relatively small amount of processing fluid is required to fill the processing space SP.

[0046] The fluid supply unit 457 supplies the processing fluid to the processing space SP further to the (+Y) side than the (+Y) side end of the substrate S. Meanwhile, the fluid recovery unit 55 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 to the (-Y) side than the (-Y) side end of the substrate S. As a result, laminar flows of the processing fluid from the (+Y) side to the (-Y) side are formed above the substrate S and below the support tray 415 in the processing space SP.

[0047] The supercritical processing control unit 97 of the control device 9 determines the pressure and temperature in the processing space SP based on the detection results from a detection unit (not shown), and controls the fluid supply unit 457 and the fluid recovery unit 455 based on the results. This appropriately manages the supply of the processing fluid to the processing space SP and the discharge of the processing fluid from the processing space SP, and adjusts the pressure and temperature in the processing space SP in accordance with a predetermined processing recipe.

[0048] 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 includes a main body 431, a lifting member 433, a base member 435, and multiple 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 top of the lifting member 433. Multiple 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 abutting its upper end with 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 ends have the same height.

[0049] The lifting member 433 can be moved 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, a linear motion guide, a ball screw mechanism, a solenoid, or an air cylinder, and this linear motion mechanism moves the lifting member 433 in the Z direction. The lifting mechanism 451 operates in response to a control command from the control device 9.

[0050] The base member 435 moves up and down as the lifting member 433 moves up and down, and the plurality of lift pins 437 move up and down integrally therewith. This allows 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 FIG. 4 , the substrate S is transferred with the support tray 415 pulled out to the outside 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 moves up, the upper ends of the lift pins 437 pass through the through holes 419 and reach a position higher than the upper surface of the support tray 415. In this state, the substrate S transferred by the transfer robot 30 is transferred from the hand 31 of the transfer robot 30 to the lift pins 437. When the lift pins 437 move down, the substrate S is transferred from the lift pins 437 to the support tray 415. The substrate S can be removed by reversing the above procedure.

[0051] Next, a more detailed description will be given of 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. In the above, it has been simply explained that the processing fluid is supplied from the fluid supply unit 457 to the processing chamber 412 and recovered from the processing chamber 412 to the fluid recovery unit 455. In an actual device, the fluid supply unit 457 and the fluid recovery unit 455 have the following configurations.

[0052] FIG. 5 is a diagram showing the details of the supply and discharge paths of the processing fluid. Note that in FIG. 5, for convenience of illustration, the orientation of the processing chamber 412 is opposite to that in FIG. 4. That is, in FIG. 4, the processing fluid is introduced into the processing chamber 412 from the right side of the page and discharged to the left side of the page. On the other hand, in FIG. 5, the processing fluid is introduced into the processing chamber 412 from the left side of the page and discharged to the right side of the page, which is the opposite of the above. That is, the processing chamber 412 in FIG. 5 shows the side opposite to that of the processing chamber 412 in FIG. 4.

[0053] First, we will explain the detailed structure of fluid supply unit 457. Fluid supply unit 457 mainly comprises a fluid supply source 700, a refinement unit 710, a supply unit 720, and piping groups 730 and 740 that connect these. These operate in response to control commands from supercritical process control unit 97.

[0054] The fluid supply source 700 outputs a substance (carbon dioxide in this embodiment) that acts as a processing fluid in supercritical processing as needed. The fluid supply source 700 may be provided as a part of the substrate processing system 1 and may be configured as a container, such as a cylinder, that stores the substance. Alternatively, the fluid supply source 700 may be an external supply source provided separately from the substrate processing system 1.

[0055] A pipe 731, which is part of a pipe group 730, is connected to the fluid supply source 700. The processing fluid delivered from the fluid supply source 700 passes through the pipe 731 in a rightward direction in FIG. 1. Valves V70, V71, a purifier 711, a filter 712, a condenser 713, and a valve V72 are inserted in this order in the processing fluid flow direction of the pipe 731. The valve V70 is, for example, a pressure regulating valve that has the function of adjusting the pressure of the processing fluid passed through the pipe 731. The other valves V71, V72 are on-off valves that switch the flow of the fluid on and off.

[0056] Valve V70 circulates the processing fluid at a pressure specified by a control command from the supercritical processing control unit 97 through pipe 731. Purifier 711 and filter 712 remove impurities from the processing fluid to improve its purity. Condenser 713 condenses the processing fluid sent out as a gas from fluid supply source 700. When valves V71 and V72 are opened, the processing fluid is output from pipe 731.

[0057] Pipe 731 merges with pipe 735, which is connected to a storage tank 717 (described later), on the output side of valve V72. Pipe 732 after the merger is equipped with a condenser 714, a pressure pump 715, and a filter 716. Condenser 714 is provided to more reliably maintain the processing fluid in a liquid state. Pressure pump 715 pressurizes the liquid processing fluid and sends it out. Filter 716 removes impurities from the processing fluid.

[0058] Pipe 732 branches into two pipes 733 and 734 on the output side of filter 716. Pipe 733 is connected to the top of storage tank 717, and has valve V74, which is an on-off valve, inserted midway through. Also, pipe 734 has valve V75, which is an on-off valve, inserted therein.

[0059] The storage tank 717 is a high-pressure vessel capable of storing pressurized liquid processing fluid. A level sensor 718 is provided in the storage tank 717 to control the liquid level. Therefore, the internal space of the storage tank 717 is not liquid-tight, and the vaporized processing fluid is stored in the space above the liquid level under pressure similar to that of the liquid. The storage tank 717 is also equipped with a heater 719, which can heat the processing fluid in the tank in response to a control command from the supercritical processing control unit 97.

[0060] A pipe 735 is connected to the bottom of the storage tank 717, and the pipe 735 merges with the pipe 731 and is connected to the pipe 732. When a valve V73, which is an on-off valve inserted in the pipe 735, is opened, the liquid processing fluid in the storage tank 717 flows into the pipe 732 via the pipe 735. If a valve V74 on the pipe 733 is also opened, a reflux path is formed that refluxes the processing fluid from the storage tank 717 via the pipes 735, 732, and 733 back to the storage tank 717. If the pressure pump 715 pressurizes the processing fluid while circulating it through this reflux path, 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 increased to a pressure designated by a control command from the supercritical processing control unit 97.

[0061] An output pipe 736 is connected to the top of the storage tank 717, and the pipe 736 merges with the pipe 734 via the valve V76, which is an on-off valve. The gaseous treatment fluid that fills the upper part of the internal space of the storage tank 717 is output from the pipe 736. The gaseous treatment fluid flows into the pipe 741 after the pipes 734 and 736 are merged, and when the valve V76 is opened, the gaseous treatment fluid flows into the pipe 741, and when the valve V75 is opened, the liquid treatment fluid flows into the pipe 741.

[0062] In this way, the purification unit 710 of the fluid supply section 457 has the function of removing impurities from the processing fluid supplied from the fluid supply source 700 and selectively outputting the processing fluid in the phase required for subsequent processing, specifically the gas phase and liquid phase.

[0063] Pipe 741 is part of a group of pipes 740 that constitutes an introduction flow path for introducing a processing fluid from purification unit 710 to processing chamber 412. Pipe 741 branches into two pipes 743 and 744, each of which is provided with filters 721 and 722. These pipes 743 and 744 merge to form pipe 745, which further branches into two pipes 747 and 748.

[0064] A flow meter 723, a heater 725, and an on-off valve V78 are inserted in this order into the pipe 742 along the flow direction of the processing fluid (toward the right in the figure), and the pipe 742 is ultimately connected to the processing chamber 412. More specifically, the pipe 742 communicates with the internal space SP above the support tray 415 (FIG. 4) that supports the substrate S. Meanwhile, a flow meter 724, a heater 726, and an on-off valve V79 are inserted in this order into the pipe 743 along the flow direction of the processing fluid. The pipe 742 communicates with the internal space SP of the processing chamber 412 below the support tray 415 (FIG. 4) that supports the substrate S. As a result, in the internal space SP, the processing fluid is supplied to the spaces above and below the substrate S placed on the support tray 415.

[0065] Flow meters 723 and 724 measure the flow rates of the processing fluid at their respective positions and transmit the results to the supercritical processing control unit 97. Heaters 725 and 726 heat the processing fluid to a predetermined temperature in response to control commands from the supercritical processing control unit 97. Filters 727 and 728 finally remove impurities from the processing fluid introduced into the processing chamber 412.

[0066] In this manner, the fluid supply unit 457 can supply a processing fluid that has been purified and whose temperature and pressure have been adjusted to predetermined target values ​​to the processing chamber 412. The supply sequence of the processing fluid from the fluid supply unit 457 to the processing chamber 412 will be described in detail later.

[0067] The processing fluid supplied to processing chamber 412 is delivered from storage tank 717, which stores processing fluid pressurized by pressure pump 715. Therefore, the pressure of the processing fluid delivered from fluid supply source 700 may be lower than the pressure required for processing. If fluid supply source 700 can stably deliver processing fluid at a pressure appropriate for processing, the gas-phase processing fluid may be supplied directly from fluid supply source 700 via piping 737, as shown by the dotted line in Figure 5, rather than being taken from storage tank 717. Alternatively, pressure-regulated processing fluid may be supplied from the output side of valve V70.

[0068] Next, we will explain the detailed structure of the fluid recovery unit 455. The fluid supply unit 455 mainly comprises a high-pressure exhaust tank 505, a low-pressure exhaust tank 508, and a group of pipes 530 connecting these. These operate in response to control commands from the supercritical process control unit 97.

[0069] A pipe 531, which is part of a pipe group 530, is connected to the upper part of the processing chamber 412. Meanwhile, a pipe 532 is connected to the lower part of the processing chamber 412. These pipes 531, 532 respectively 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 the pipe 531.

[0070] A flow meter 501 and a valve V51, which is an on-off valve, are inserted in this order into pipe 531 along the flow direction of the processing fluid. On the other hand, a flow meter 502 and a valve V52, which is an on-off valve, are inserted in this order into pipe 532 along the flow direction of the processing fluid. Pipes 531 and 532 join at the output sides of valves V51 and V52. After joining, pipe 533 has valve V53, which is a pressure adjustment valve, and valve V54, which is an on-off valve, inserted therein.

[0071] The pipe 533 is connected to a high-pressure exhaust tank 505, and the processing fluid discharged from the processing chamber 412 is stored in the high-pressure exhaust tank 505 via the pipe 533. The high-pressure exhaust tank 505 is provided with a heater 506, which maintains the temperature of the processing fluid stored therein at an appropriate level.

[0072] A pipe 544 is connected to the top of the high-pressure exhaust tank 505, and a valve V55 which is an on-off valve, a valve V56 which is a pressure adjusting valve, and a heater 507 are inserted in the pipe 544, and the pipe 544 is finally connected to a low-pressure exhaust tank 508. Therefore, a processing fluid as a gas whose pressure and temperature have been appropriately adjusted 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 the pipe 545. A pressure sensor 510 is provided in the pipe 545 to detect the pressure of the gas discharged to the outside.

[0073] Furthermore, a pipe 546 is connected to the bottom of the high-pressure exhaust tank 505, while a pipe 547 is connected to the bottom of the low-pressure exhaust tank 508. These pipes join to form pipe 548, to which a valve V57, which is 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.

[0074] Various types of flow meters capable of detecting the flow rate of a fluid in a flow path can be applied as the flow meters 501, 502, 723, and 724. It is preferable that the flow meters be capable of detecting the density of the fluid, and for example, a mass flow meter, or more specifically, a Coriolis flow meter, can be used.

[0075] The operation of the supercritical processing apparatus 4 configured as described above will be described with reference to Figures 6 and 7. The supercritical processing apparatus 4 performs a process of drying the substrate S after wet processing using a processing fluid in a supercritical state, i.e., a supercritical drying process. This process is realized by the CPU 91 of the control unit 9 executing a prepared control program and controlling each part of the apparatus.

[0076] Fig. 6 is a flowchart showing the process performed by the supercritical processing apparatus. Fig. 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 to the processing chamber 412 from a storage tank 717 that stores the processing fluids. Therefore, 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 storage tank 717 (hereinafter referred to as "tank internal pressure") change as the process progresses.

[0077] 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 that has undergone the liquid film formation process in the wet processing device 2, and places the substrate S on the support tray 415 that 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 pins 437 of the supercritical processing device 4, and then the substrate S is transferred from the lift pins 437 to the support tray 415.

[0078] 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. In this way, 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, the internal pressure of the processing chamber 412 is atmospheric pressure Pa in the initial state, as shown in the upper part of FIG.

[0079] While the substrate S is being transferred in this manner, a predetermined standby operation is performed in the fluid supply unit 457 (step S102). As will be described in detail later, the standby operation is an operation for preparing a required amount of processing fluid at a temperature and pressure suitable for use in subsequent processing in the fluid supply unit 457. As will be described later, in this embodiment, gaseous carbon dioxide at a temperature of 20°C and a pressure of 6 MPa and carbon dioxide heated to a temperature of 20°C and a pressure of 11 MPa to become supercritical are used for processing.

[0080] After the substrate S is loaded, the fluid supply unit 457 starts to introduce a gaseous processing fluid (step S103; time T1), which gradually increases the pressure inside the chamber. When the pressure inside the chamber increases to a predetermined first pressure P1 (step S104; time T2), the fluid supply unit 457 supplies a supercritical processing fluid, instead of the gas, into the processing chamber 412 (step S105; time T3).

[0081] As a result, the processing space SP of the processing chamber 412 is filled with the processing fluid in a supercritical state, and the chamber internal pressure is maintained at a constant second pressure P2 that is greater than the first pressure P1 and the critical pressure of the processing fluid (times T4 to T5). During this time, the liquid remaining on the substrate S is replaced by the supercritical processing fluid, dissolved in the processing fluid, and removed from the surface of the substrate S.

[0082] After a predetermined time has elapsed while the chamber internal pressure is maintained at approximately pressure P2 (step S106), discharge of the processing fluid from the processing chamber 412 begins (step S107; time T5), thereby depressurizing the processing space SP. After time T7, when the chamber internal pressure has decreased to near atmospheric pressure Pa, the transfer robot 30 unloads the substrate S (step S108), completing the processing of one substrate S. If there is another substrate to be processed, the process returns to step S101 (step S109), and the above processing is repeated.

[0083] 7, as the processing fluid stored in the storage tank 717 is consumed, the pressure inside the tank gradually decreases. To restore this pressure, a standby operation is performed to replenish the storage tank 717 with pressurized processing fluid (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 FIG. 7, the standby operation can be started while the processing chamber 412 is being depressurized.

[0084] When performing supercritical drying processing on a substrate S, it is desirable to increase the tank internal pressure to a pressure that is approximately the same as or slightly higher than the first pressure P1 during the standby operation so that the chamber internal pressure can be increased to the first pressure P1 in step S103 of the processing.

[0085] Specifically, the processing fluid output from the fluid supply source 700 is pressurized by the pressure pump 715 and flows into the storage tank 717, thereby increasing the pressure inside the tank to a target value. For this purpose, the valves V71, V72, and V74 are opened, while the valves V73, V75, and V76 are closed.

[0086] Therefore, the processing fluid output from the fluid supply source 700 and having its pressure adjusted by the valve V70 is pressurized to a predetermined pressure by the pressure 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 the processing fluid continues until a predetermined amount of liquid at a predetermined pressure has accumulated. In addition, the temperature of the processing fluid in the tank is adjusted by the heater 719.

[0087] Thus, during the standby 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 FIG. 7), a process for maintaining the liquid volume, pressure, and temperature in the tank at predetermined values ​​is performed as a standby operation. The target pressure value is the first pressure P1 or a pressure slightly higher than this, which is 6 MPa in this embodiment. The target temperature is 20°C in this embodiment. The target liquid volume value is set to an amount that is sufficient to supply the processing fluid to the processing chamber 412 in the supercritical drying process described above.

[0088] Next, the supply and discharge control of the processing fluid in the above-mentioned supercritical drying process will be described. In the above explanation, it was simply assumed that the supercritical control unit 97 controls the fluid supply unit 457 and the fluid recovery unit 455 in accordance with a predetermined processing recipe, thereby controlling the pressure and temperature in the processing chamber 412 to target values. Here, the operation of the supercritical control unit 97 at this time will be described in more detail.

[0089] Figure 8 is a flowchart showing an overview of the supply and discharge control of processing fluids. In supercritical drying processing, a supercritical control unit 97 controls the operation of each part of the apparatus based on a processing recipe that defines the operation of each part for each time. Each of the valves V71 to V79 and V51 to V57 shown in Figure 5 is opened and closed based on the processing recipe. Specifically, the opening of the valve at each time is specified by the processing recipe, and processing fluid flows through each pipe at a flow rate according to the pressure of the processing fluid on the input side of each valve and the valve opening.

[0090] When processing starts, the opening of each valve is adjusted based on the processing recipe (step S201). When the supply of processing fluid to the processing space SP starts (time T1 in FIG. 7), the fluid supply unit 457 opens the valves V76 to V79 to the openings specified by the processing recipe, and the processing fluid is supplied as a gas to the processing chamber 412.

[0091] At this time, each valve of the fluid recovery unit 455 may be closed, or some valves may be opened to discharge air from the processing space SP. This allows the processing fluid to purge the outside air that entered the processing space SP when the substrate S was loaded. By making the outflow rate of the processing fluid smaller than the inflow rate, the processing SP can be pressurized.

[0092] During processing, the flow rate of the processing fluid and the pressure inside the chamber are detected constantly or periodically (step S202). Specifically, flow meter 723 detects the flow rate of the processing fluid supplied to the space above the substrate S in the processing space SP, and flow meter 724 detects the flow rate of the processing fluid supplied to the space below the support tray 415 in the processing space SP. Furthermore, flow meter 501 detects the flow rate of the processing fluid discharged from the space above the substrate S in the processing space SP, and flow meter 502 detects the flow rate of the processing fluid discharged from the space below the support tray 415 in the processing space SP. Furthermore, pressure meter 503 provided on piping 531 communicating with the processing space SP detects the pressure inside the processing space SP, i.e., the chamber pressure.

[0093] It is determined whether the detected value by each flow meter 723, 724, 501, 502 is a predetermined appropriate flow rate (step S203). The appropriate flow rate may be determined as a numerical range having a certain width. If the flow rate of the processing fluid is not appropriate, the processing quality cannot be guaranteed. Therefore, in such a case (NO in step S203), exception processing (step S220) is executed to terminate the processing. The content of the exception processing is arbitrary, and some examples will be described later.

[0094] If the flow rates of the processing fluids in each flow path are all appropriate (YES in step S203), the processing continues. That is, it is determined whether the chamber internal pressure detected by the pressure gauge 503 is the appropriate pressure specified in the processing recipe (step S204). If the pressure is appropriate (YES in step S204), the processing returns to step S201 and continues until the determined processing recipe is completed (step S205).

[0095] That is, at time T2, valve V76 is closed, and valve V75 is opened instead. As a result, liquid processing fluid is delivered to pipe 741. The liquid is heated by heaters 725, 726 to a supercritical state and flows into processing chamber 412. After time T4, processing fluid is simultaneously supplied to and discharged from processing chamber 412, thereby maintaining processing space SP at a constant pressure P2. Then, at time T5, the supply rate of processing fluid is reduced while the discharge rate is increased, thereby lowering the pressure inside the chamber. Each of these steps is achieved by changing the opening of each valve according to the processing recipe.

[0096] During these processes, if step S204 returns NO, meaning the detected chamber pressure is not appropriate, the valve openings are changed to restore the pressure (step S210). That is, if the chamber pressure is lower than the target value, the valve openings are adjusted to increase the inflow rate of the processing fluid, decrease the outflow rate, or both. Conversely, if the chamber pressure is too high relative to the target value, the valve openings are adjusted to decrease the inflow rate of the processing fluid, increase the outflow rate, or both. Then, the process returns to step S202, where the flow rate and pressure are detected. The operations described above are then repeated.

[0097] Next, an example of exception handling (step S220) will be described. There are various possible reasons why the flow rate of the processing fluid in the flow path deviates from the appropriate value, but a major reason for a decrease in the inflow rate is clogging of the filter in the flow path. Because clogging increases irreversibly, recovery of the flow rate is not expected. Therefore, as an exception handling in this case, for example, it is possible to notify the operator of the abnormality or display a message urging replacement of the filter element.

[0098] More specifically, for example, if the flow rate detection result of flow meter 723 is below the appropriate value while the detection result of flow meter 724 is the appropriate value, then clogging of filter 727 on pipe 747 where flow meter 723 is installed is suspected. Conversely, if the detection result of flow meter 723 is appropriate and the detection result of flow meter 724 is below the appropriate value, then clogging of filter 728 on pipe 748 where flow meter 724 is installed is suspected. If a decrease in flow rate is detected by both flow meters, then clogging of filters 721, 722 is suspected. It is also possible to issue a notification appropriate to each of these cases depending on the detection results of each flow meter.

[0099] Furthermore, if the fluctuation in the flow rate is slight, it is possible to optimize the flow rate by adjusting the valve opening. For example, this can be done as follows.

[0100] Figure 9 is a flowchart showing a modified example of the control mode for supplying and discharging the processing fluid. This process differs from the process of Figure 8 in that step S211 has been added, but the rest is the same. In step S211, which is executed when the pressure detection result is outside the appropriate value, the valve to be adjusted is selected based on the detection result of the flow rate in each flow path.

[0101] Specifically, for example, if the pressure is lower than the appropriate value, it can be determined from the flow rate detection results in each flow path whether the cause is a decrease in the inflow rate or an excessive outflow rate. If the inflow rate is lower, the pressure can be restored by, for example, increasing the opening of one or both of V78 and V79 in step S210 to increase the inflow rate. If it is determined that the outflow rate is increasing, the pressure can be restored by, for example, decreasing the opening of one or both of V51 and V52 to decrease the outflow rate.

[0102] Similarly, if the pressure is excessive, the valve opening can be changed to reduce the inflow if the inflow is large, or to increase the outflow if the outflow is small, thereby restoring the pressure inside the chamber to an appropriate value.

[0103] As such, there are various ways to consider how the flow rate detection results can be used, and the content of the exception processing to be performed when the flow rate is inappropriate is arbitrary. However, if the problem is due to a clogged filter, the situation may worsen over time, but recovery is not expected. Therefore, even if it is possible to temporarily maintain processing quality by feeding back the detection results to the valve opening and increasing the supply amount, it is not desirable to continue processing in this state in the long term. Therefore, it is effective to display a warning to the operator to prompt maintenance, such as replacing the filter element.

[0104] As described above, in the supercritical processing apparatus 4 of this embodiment, the opening degree of each valve arranged in the flow path that supplies processing fluid to the processing chamber 412 or discharges processing fluid from the processing chamber 412 is adjusted based on a predetermined processing recipe so that the change in chamber internal pressure over time follows a predetermined profile. The amount of processing fluid actually flowing through each flow path is detected. In particular, since both the amount of processing fluid flowing into the processing chamber 412 and the amount of processing fluid flowing out of the processing chamber 412 are detected, it is possible to grasp the balance between them.

[0105] The problem of filter clogging manifests as a decrease in flow rate due to increased pressure loss, and so changes in the flow rate of the processing fluid passing through the filter can be detected by monitoring the flow rate. Filter clogging is not necessarily a temporary phenomenon. Since recovery is unlikely and the condition will gradually worsen over time, a practical response is to issue a notification to the operator urging them to perform maintenance, such as replacing the filter element. This can stabilize the processing quality of substrates over the long term.

[0106] As described above, in the above embodiment, the supercritical processing apparatus 4 corresponds to the "substrate processing apparatus" of the present invention, and the processing chamber 412 having the processing space SP as an "internal space" functions as the "processing chamber" of the present invention. The fluid supply unit 457 and the fluid recovery unit 455 function as the "supply unit" and the "discharge unit," respectively. The supercritical processing control unit 97 functions as the "control unit" of the present invention. The support tray 415 corresponds to the "support member" of the present invention. The piping groups 730 and 740 and the valve groups disposed thereon collectively constitute the "introduction flow path" of the present invention. The pressure pump 715 functions as the "pressure boosting mechanism" of the present invention.

[0107] Furthermore, filters 727 and 728 function as the "filter section" of the present invention. Of these, pipe 747 in which filter 727 is provided corresponds to the "upper inlet flow path" of the present invention, and pipe 748 in which filter 728 is provided corresponds to the "lower inlet flow path" of the present invention. Furthermore, flow meters 723 and 724 function as the "first detection section" of the present invention. Furthermore, heaters 725 and 726 function as the "heating section" of the present invention.

[0108] Furthermore, pipe group 530 and the valve group disposed therein together constitute the "discharge flow path" of the present invention. Among them, pipe 531 corresponds to the "upper discharge flow path" of the present invention, and pipe 532 corresponds to the "lower discharge flow path" of the present invention. Furthermore, flow meters 501 and 502 function as the "second detection unit" of the present invention.

[0109] The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the processing fluid is introduced into the processing chamber 412 and discharged from the processing chamber 412 separately from the upper and lower sides of the support tray 415. However, this is not an essential requirement.

[0110] For example, in the above embodiment, the flow rate detection results of the processing fluid in the flow path are reflected in the notification to the operator, but the manner in which the flow rate detection results are used is not limited to this. For example, as exemplified above as a modified example, a valve whose opening is changed based on the flow rate detection results can be selected. Furthermore, for example, the inflow and outflow rates of the processing fluid, in addition to the pressure, can be set by a processing recipe, and a control sequence can be constructed in which these flow rates change according to the processing recipe.

[0111] However, even in this case, it is preferable to notify the operator when the inflow rate drops, because, as mentioned above, the drop in flow rate caused by filter clogging is an irreversible phenomenon, and in the long run, it will inevitably become impossible to deal with the problem even with the above-mentioned control.

[0112] Furthermore, the various chemical substances and numerical values ​​used in the processing of the above-described embodiments are only examples, and various other substances can be used instead as long as they are consistent with the technical concept of the present invention described above.

[0113] As described above with reference to specific embodiments, in the present invention, a plurality of inlet flow paths may be connected to a processing chamber, and flow rate detection may be performed individually for each of the plurality of inlet flow paths. In this case, it is preferable that a filter unit is provided in each of the plurality of pre-inlet flow paths. Also, a plurality of outlet flow paths may be connected to the processing chamber, and flow rate detection may be performed individually for each of the plurality of outlet flow paths. With these configurations, it is possible to determine in which flow path a flow rate fluctuation is occurring, and therefore it is possible to take appropriate measures depending on the situation.

[0114] Furthermore, for example, the inlet flow path may be provided with a heating unit that heats the processing fluid to a temperature equal to or higher than the critical temperature. With such a configuration, for example, a processing fluid supplied as a liquid can be brought to a supercritical state by heating. Furthermore, for example, the inlet flow path may be provided with a pressure-boosting mechanism that pressurizes the processing fluid to a pressure higher than the critical pressure. With such a configuration, the processing fluid is circulated through the inlet flow path in a pressurized state, and is finally heated to a temperature equal to or higher than the critical temperature, thereby bringing the processing fluid to a supercritical state. In this case, the flow rate can be detected, for example, in a liquid state.

[0115] Furthermore, when the substrate device according to the present invention includes, for example, a flat support member that supports the substrate in a horizontal position within the internal space, the inlet flow path may include an upper inlet flow path that supplies the processing fluid to a space within the internal space above the substrate and a lower inlet flow path that supplies the processing fluid to a space within the internal space below the support member, and the flow rate may be detected in each of the upper inlet flow path and the lower inlet flow path.Furthermore, the outlet flow path may include an upper outlet flow path that discharges the processing fluid from a space within the internal space above the substrate and a lower outlet flow path that discharges the processing fluid from a space within the internal space below the support member, and the flow rate may be detected in each of the upper outlet flow path and the lower outlet flow path.

[0116] With this configuration, a flow of processing fluid is formed above the substrate and below the support member within the processing chamber, and the inflow and outflow amounts of the processing fluid forming each flow are detected separately, making it possible to detect fluctuations that may disturb the flows early and take appropriate action.

[0117] In the present invention, the flow rate of the processing fluid may be measured using a mass flow meter. The ultimate purpose of detecting the pressure and flow rate of the processing fluid is to maintain an appropriate density of the processing fluid in the processing chamber. Therefore, it is desirable to detect the flow rate by detecting the mass of the processing fluid passing through.

[0118] Furthermore, the present invention can be configured to issue a warning if the flow rate detection result of the processing fluid in any of the flow paths differs from a predetermined optimum value. Filter clogging is a major factor that causes flow rate fluctuations, but this is an irreversible phenomenon, and it is difficult to fundamentally solve the resulting flow rate fluctuations and the resulting degradation in processing quality. Therefore, issuing a warning to the operator to prompt them to, for example, perform filter maintenance will help maintain processing quality in the long term. [Industrial Applicability]

[0119] The present invention can be applied to any technique for processing a substrate with a processing fluid in a supercritical state in a processing chamber. [Explanation of symbols]

[0120] 4. Supercritical processing equipment (substrate processing equipment) 97 Supercritical Processing Control Unit (Control Unit) 412 Processing Chamber 415 Support tray (support member) 455 Fluid recovery section (discharge section) 457 Fluid supply section (supply section) 501, 502 Flow meter (second detection unit) 530 Piping group (exhaust flow path) 531 Piping (upper discharge flow path) 532 Piping (lower discharge channel) 715 Pressure pump (boosting mechanism) 723,724 Flow meter (first detection part) 725,726 Heater (heating part) 727,728 Filter (filter section) 730,740 Piping group (inlet flow path) 747 Piping (upper inlet flow path) 748 Piping (lower inlet flow path) S board SP Processing space (internal space)

Claims

1. 1. A substrate processing apparatus for processing a substrate with a processing fluid in a supercritical state, a processing chamber having an interior space capable of accommodating the substrate; a supply section for supplying the processing fluid to the processing chamber; a discharge section for discharging the processing fluid from the processing chamber; a control unit that controls the supply unit and the exhaust unit to change the pressure in the internal space in accordance with a predetermined processing recipe; a filter unit provided in an introduction flow path of the processing fluid from the supply unit to the processing chamber, the filter unit filtering the processing fluid; a first detection unit provided in the inlet flow path between the supply unit and the filter unit, the first detection unit detecting a flow rate of the treatment fluid flowing through the inlet flow path; a second detection unit provided in a discharge flow path of the processing fluid extending from the processing chamber to the discharge unit, the second detection unit detecting a flow rate of the processing fluid flowing through the discharge flow path; A substrate processing apparatus comprising:

2. The substrate processing apparatus according to claim 1 , wherein a plurality of the introduction channels are connected to the processing chamber, and the first detection unit detects the flow rate for each of the plurality of introduction channels individually.

3. The substrate processing apparatus according to claim 2 , wherein the filter unit is provided in each of the plurality of introduction channels.

4. The substrate processing apparatus according to claim 1 , further comprising a heating unit provided in the inlet passage for heating the processing fluid to a critical temperature or higher.

5. The substrate processing apparatus according to claim 1 , wherein a plurality of the exhaust flow paths are connected to the processing chamber, and the second detection unit detects the flow rate individually for each of the plurality of the exhaust flow paths.

6. a flat support member that supports the substrate in a horizontal position within the internal space; the introduction flow path has an upper introduction flow path that supplies the processing fluid to a space in the internal space above the substrate, and a lower introduction flow path that supplies the processing fluid to a space in the internal space below the support member, and the first detection unit detects the flow rate in each of the upper introduction flow path and the lower introduction flow path; 2. The substrate processing apparatus of claim 1, wherein the discharge flow path has an upper discharge flow path that discharges the processing fluid from a space in the internal space above the substrate, and a lower discharge flow path that discharges the processing fluid from a space in the internal space below the support member, and the second detection unit detects the flow rate in each of the upper discharge flow path and the lower discharge flow path.

7. The substrate processing apparatus according to claim 1 , wherein the inlet passage is provided with a pressure increasing mechanism for increasing the pressure of the processing fluid to a pressure higher than a critical pressure.

8. 8. The substrate processing apparatus according to claim 1, wherein the first detection unit and the second detection unit each have a mass flow meter that detects the flow rate.

9. The substrate processing apparatus according to claim 1 , wherein the control unit issues a warning when a detection result of either the first detection unit or the second detection unit differs from a predetermined optimum value.

10. 1. A substrate processing method for processing a substrate with a processing fluid in a supercritical state, comprising: a first step of accommodating the substrate in an internal space of a processing chamber; a second step of supplying the processing fluid to the internal space and discharging the processing fluid from the internal space to fill the internal space with the processing fluid in a supercritical state; a third step of discharging the treatment fluid from the internal space; Equipped with In the second step, The treatment fluid filtered by the filter unit is supplied to the internal space, a supply amount of the processing fluid flowing into the filter unit and a discharge amount of the processing fluid discharged from the internal space, and adjusting the supply amount and the discharge amount so that the pressure in the internal space changes in accordance with a predetermined processing recipe.

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