Substrate processing method and substrate processing device

Abstract

To stably encapsulate a process fluid in a supercritical state inside of a processing container for a long time.SOLUTION: Disclosed is a substrate processing method for a substrate processing device which processes a substrate in contact with a process fluid in a supercritical state. The substrate processing device comprises: a processing container including a processing space in which the substrate can be stored; a main supply line which includes a second opening / closing valve and supplies the process fluid to the processing space; a discharge line which includes a first opening / closing valve and discharges the process fluid from the processing space; and a bypass line which is branched at a branch point upstream of the second opening / closing valve in the main supply line and confluent at a confluence point downstream of the first opening / closing valve in the discharge line. The substrate processing method includes a boosting step and a holding step. In the boosting step, a pressure in the processing space is boosted to a critical pressure or higher by supplying the process fluid from the main supply line to the processing space in a state where the substrate is stored in the processing space. In the holding step, the process fluid is circulated in the bypass line in a state where the second opening / closing valve and the first opening / closing valve are closed after the boosting step.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus. [Background technology]

[0002] In the manufacturing process of a semiconductor device in which a laminated structure of integrated circuits is formed on the surface of a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer), a substrate processing method is known in which a processing fluid in a supercritical state to which an additive has been added is sealed in a processing vessel for a long period of time (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2008-532268 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can stably contain a processing fluid in a supercritical state within a processing vessel for an extended period of time. [Means for solving the problem]

[0005] A substrate processing method according to one aspect of the present disclosure is a substrate processing method for a substrate processing apparatus that processes a substrate by contacting it with a processing fluid in a supercritical state. The substrate processing apparatus includes a processing vessel, a main supply line, a discharge line, and a bypass line. The processing vessel has a processing space capable of accommodating the substrate. The main supply line has a second on-off valve and supplies the processing fluid to the processing space. The discharge line has a first on-off valve and discharges the processing fluid from the processing space. The bypass line branches off from the main supply line at a branch point upstream of the second on-off valve and joins the discharge line at a junction downstream of the first on-off valve. The substrate processing method according to one aspect of the present disclosure also includes a pressurization step and a holding step. The pressurization step supplies the processing fluid from the main supply line to the processing space while the substrate is accommodated in the processing space, thereby increasing the pressure in the processing space to or above critical pressure. In the holding step, after the pressurizing step, the treatment fluid is circulated through the bypass line with the second on-off valve and the first on-off valve closed. [Effects of the Invention]

[0006] According to the present disclosure, a processing fluid in a supercritical state can be stably contained within a processing vessel for a long period of time. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the configuration of the supply processing unit according to the embodiment. [Figure 3] FIG. 3 is an external perspective view showing an example of the configuration of the substrate processing unit according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of supply lines and discharge lines connected to the substrate processing unit according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of the procedure of each process performed by the substrate processing unit according to this embodiment. [Figure 6] FIG. 6 is a diagram showing an example of the change over time in pressure in the processing space during the pressure increase process, the holding process, the circulation process, and the pressure reduction process according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the operation of the boosting process according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the operation of the holding process according to the embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of the operation of the distribution process according to the embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of the operation of the decompression process according to the embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the operation of the decompression process according to the embodiment. [Figure 12] FIG. 12 is a diagram showing an example of the operation of the holding process according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a substrate processing method and a substrate processing apparatus disclosed herein will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments described below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from the actual situation. Furthermore, the dimensional relationships and ratios may differ between the drawings.

[0009] In the manufacturing process of a semiconductor device in which a laminated structure of integrated circuits is formed on the surface of a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer), a substrate processing method is known in which a processing fluid in a supercritical state to which an additive has been added is sealed in a processing vessel for a long period of time.

[0010] On the other hand, when confining a high-pressure supercritical processing fluid in a processing vessel, leakage occurs from valves, etc., making it difficult to stably contain the supercritical processing fluid in the processing vessel for a long period of time.

[0011] Therefore, there is a need for a technology that can overcome the above-mentioned problems and stably confine a processing fluid in a supercritical state within a processing vessel for a long period of time.

[0012] <Outline of the substrate processing system> First, a schematic configuration of a substrate processing system 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing a schematic configuration of a substrate processing system 1 according to an embodiment. In the following, to clarify the positional relationship, mutually orthogonal X-axis, Y-axis, and Z-axis are defined, and the positive direction of the Z-axis is defined as the vertically upward direction.

[0013] 1, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3. The substrate processing system 1 is an example of a substrate processing apparatus. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0014] The loading / unloading station 2 includes a carrier placement section 11 and a transport section 12. A plurality of carriers C, each of which accommodates a plurality of semiconductor wafers W (hereinafter referred to as "wafers W") in a horizontal position, are placed on the carrier placement section 11. The wafers W are an example of a substrate.

[0015] The transfer section 12 is provided adjacent to the carrier placement section 11 and includes a substrate transfer device 13 and a transfer section 14. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 13 is capable of moving horizontally and vertically and rotating about a vertical axis, and transfers the wafer W between the carrier C and the transfer section 14 using the wafer holding mechanism.

[0016] The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport section 15, a plurality of supply processing units 16, and a plurality of substrate processing units 17. The plurality of supply processing units 16 and the plurality of substrate processing units 17 are provided side by side on both sides of the transport section 15. The arrangement and number of supply processing units 16 and substrate processing units 17 shown in FIG. 1 are merely an example and are not limited to those shown in the figure.

[0017] The transfer section 15 includes a substrate transfer device 18 therein. The substrate transfer device 18 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 18 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the delivery section 14, the supply processing unit 16, and the substrate processing unit 17 using the wafer holding mechanism.

[0018] The supply processing unit 16 performs a given additive supply process on the wafer W transferred by the substrate transfer device 18. An example of the configuration of the supply processing unit 16 will be described later.

[0019] The substrate processing unit 17 performs a given substrate processing on the wafer W to which the additive has been supplied by the supply processing unit 16. An example of the configuration of the substrate processing unit 17 will be described later.

[0020] The substrate processing system 1 also includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 19 and a storage unit 20.

[0021] The control unit 19 includes a microcomputer and various circuits that have a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output ports, etc. The CPU of the microcomputer reads and executes programs stored in the ROM to realize the control described below.

[0022] Such a program may be recorded on a computer-readable recording medium and installed from that recording medium into the storage unit 20 of the control device 4. Examples of computer-readable recording media include hard disks (HDs), flexible disks (FDs), compact disks (CDs), magnetic optical disks (MOs), and memory cards.

[0023] The storage unit 20 is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk.

[0024] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 in the loading / unloading station 2 removes the wafer W from the carrier C placed on the carrier placement unit 11 and places the removed wafer W on the delivery unit 14. The wafer W placed on the delivery unit 14 is then removed from the delivery unit 14 by the substrate transfer device 18 in the processing station 3 and carried into the supply processing unit 16.

[0025] The wafer W carried into the supply processing unit 16 is subjected to an additive supply process by the supply processing unit 16, and then carried out from the supply processing unit 16 by the substrate transfer device 18. The wafer W carried out from the supply processing unit 16 is carried into the substrate processing unit 17 by the substrate transfer device 18, and is subjected to substrate processing by the substrate processing unit 17.

[0026] The wafer W that has been processed by the substrate processing unit 17 is carried out of the substrate processing unit 17 by the substrate transfer device 18 and placed on the transfer section 14. Then, the processed wafer W placed on the transfer section 14 is returned to the carrier C on the carrier placement section 11 by the substrate transfer device 13.

[0027] <Configuration of supply processing unit> Next, the configuration of the supply processing unit 16 will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing an example of the configuration of the supply processing unit 16 according to the embodiment. The supply processing unit 16 is configured as, for example, a single-wafer supply processing unit that supplies additive A to the upper surfaces of wafers W one by one.

[0028] As shown in FIG. 2, the supply processing unit 16 holds the wafer W substantially horizontally using a wafer holding mechanism 25 disposed in an outer chamber 23 that forms the processing space, and rotates the wafer W by rotating the wafer holding mechanism 25 around a vertical axis.

[0029] The supply processing unit 16 then advances the nozzle arm 26 above the rotating wafer W and supplies the additive A from the nozzle 26 a provided at the tip of the nozzle arm 26, thereby performing an additive supply process on the upper surface of the wafer W.

[0030] The additive A supplied in the additive supply process is, for example, a mixture of a low-hydric alcohol (e.g., ethanol, methanol, IPA (isopropyl alcohol), etc.) and a liquid having a different polarity from the low-hydric alcohol. The additive A is also a liquid that has a high affinity with CO2 (carbon dioxide) used as the processing fluid.

[0031] The additive A is mixed in advance at a given ratio and stored in the storage unit 28. The storage unit 28 has a tank 28a and a sealed container 28b. The additive A, which has been mixed in advance at a given ratio, is stored in the tank 28a.

[0032] It is preferable that the tank 28a is provided with an internal stirring mechanism (not shown), so that the additive A, which is a mixture of multiple chemicals with different polarities, can be supplied to the wafer W in a well-mixed state.

[0033] The sealed container 28b stores the tank 28a therein and separates the internal space in which the tank 28a is housed from the external space.

[0034] Furthermore, the control unit 19 (see FIG. 1) operates the nitrogen gas supply unit 27 to supply nitrogen gas into the inside of the tank 28a, thereby increasing the pressure inside the sealed container 28b. As a result, the additive A is supplied to the nozzle 26a through the additive supply path 29a of the additive supply unit 29 connected between the inside of the tank 28a and the nozzle 26a.

[0035] Nitrogen gas supply unit 27 includes nitrogen gas supply source 27a, nitrogen gas supply path 27b, flow rate regulator 27c, and filter 27d. Nitrogen gas supply source 27a is, for example, a tank that stores nitrogen gas. Nitrogen gas supply path 27b connects nitrogen gas supply source 27a to the inside of tank 28a and supplies nitrogen gas from nitrogen gas supply source 27a to the inside of tank 28a.

[0036] Flow rate regulator 27c is disposed in nitrogen gas supply path 27b and regulates the flow rate of nitrogen gas supplied to tank 28a. Flow rate regulator 27c includes an on-off valve, a flow rate control valve, a flow meter, etc. Filter 27d filters the nitrogen gas flowing through nitrogen gas supply path 27b.

[0037] Furthermore, a valve 29b is provided in the additive supply path 29a of the additive supply unit 29. The control unit 19 can control whether or not the additive A is supplied to the nozzle 26a by opening and closing the valve 29b.

[0038] In the additive supplying process according to the embodiment, additive A is supplied to the entire upper surface of the wafer W while rotating the wafer holding mechanism 25, and then the rotation of the wafer holding mechanism 25 is gradually stopped.

[0039] The wafer W having completed the additive supply process in this manner is transferred to the substrate transfer device 18 by a transfer mechanism (not shown) provided in the wafer holding mechanism 25 with a mound of additive A on its upper surface, in other words, with a liquid film of additive A formed on the upper surface of the wafer W. Thereafter, the wafer W is unloaded from the supply processing unit 16.

[0040] In this additive supplying process, the additive A that overflows from the wafer W is received by the outer chamber 23 or the inner cup 24 disposed in the outer chamber 23.

[0041] Then, additive A is discharged from drain port 23a provided at the bottom of outer chamber 23 and drain port 24a provided at the bottom of inner cup 24. Furthermore, the atmosphere inside outer chamber 23 is exhausted from exhaust port 23b provided at the bottom of outer chamber 23.

[0042] After the additive supply process in the supply process unit 16 is completed, the wafer W having a puddle of additive A on its upper surface is transferred to the substrate process unit 17.

[0043] Then, in the substrate processing unit 17, the additive A on the upper surface of the wafer W is mixed with a processing fluid in a supercritical state (hereinafter referred to as "supercritical fluid"), and the supercritical fluid is brought into contact with the wafer W, thereby performing substrate processing on the wafer W.

[0044] <Configuration of the substrate processing unit> Next, the configuration of the substrate processing unit 17 will be described with reference to Fig. 3. Fig. 3 is an external perspective view showing an example of the configuration of the substrate processing unit 17 according to this embodiment.

[0045] 3, the substrate processing unit 17 includes a processing vessel 31, a holding plate 32, and a lid member 33. The processing vessel 31 has an opening 34 for loading and unloading the wafer W. The holding plate 32 holds the wafer W to be processed in a horizontal direction. The lid member 33 supports the holding plate 32 and seals the opening 34 when the wafer W is loaded into the processing vessel 31.

[0046] The processing vessel 31 has an internal processing space capable of accommodating a wafer W having a diameter of, for example, 300 mm. A first supply header 36, a second supply header 37, and a discharge header 38 are provided in the processing space.

[0047] The first supply header 36, the second supply header 37 and the discharge header 38 have a plurality of openings formed in the longitudinal direction, specifically, aligned along the horizontal direction (X-axis direction) perpendicular to the direction in which the wafer W is loaded and unloaded (Y-axis direction).

[0048] The first supply header 36 is connected to a main supply line 50 and supplies the processing fluid supplied from the main supply line 50 to the processing space.

[0049] Specifically, the first supply header 36 is installed at the bottom of the processing space with multiple openings facing upward, and supplies processing fluid from below the wafer W (not shown) contained in the processing space toward the underside of the wafer W.

[0050] The first supply header 36 only needs to supply the processing fluid to the processing space from at least below the wafer W, and does not necessarily need to supply the processing fluid upward.

[0051] The second supply header 37 is connected to the sub-supply line 51 and supplies the processing fluid from the sub-supply line 51 to the processing space. The downstream end of the sub-supply line 51 branches into branch supply lines 51b and 51c.

[0052] The branch supply line 51b is connected to one end of the second supply header 37 in the longitudinal direction, and the branch supply line 51c is connected to the other end of the second supply header 37 in the longitudinal direction.

[0053] The second supply header 37 is provided adjacent to the side surface of the processing space opposite the opening 34. The multiple openings formed in the second supply header 37 are positioned above the wafers W (not shown) accommodated in the processing space and face the opening 34. The second supply header 37 supplies the processing fluid supplied from the sub-supply line 51 substantially horizontally from the side surface of the processing space opposite the opening 34 toward the opening 34.

[0054] The discharge header 38 is connected to the discharge line 52 and is provided adjacent to the side of the processing space on the opening 34 side and below the opening 34. A plurality of openings formed in the discharge header 38 face the second supply header 37. The discharge header 38 discharges the processing fluid in the processing space to the discharge line 52.

[0055] The upstream end of the discharge line 52 branches into branch discharge lines 52a and 52b. The branch discharge line 52a is connected to one end of the discharge header 38 in the longitudinal direction, and the branch discharge line 52b is connected to the other end of the discharge header 38 in the longitudinal direction.

[0056] The substrate processing unit 17 supplies a processing fluid from the main supply line 50 to the processing space of the processing vessel 31 via the first supply header 36, thereby increasing the pressure in the processing space (pressure increase process, which will be described later).

[0057] Thereafter, in the substrate processing unit 17, the valves 109, 111, 118 (see FIG. 4) provided on the main supply line 50, the sub-supply line 51, and the discharge line 52, respectively, are all closed.

[0058] As a result, the processing space of the processing vessel 31 is maintained at a given processing pressure P1 (see FIG. 5) (maintenance process described below), and the wafer W is subjected to a given substrate process using the processing fluid containing the additive A. Examples of such substrate processes include oxidation, deuteration, and hydroxylation.

[0059] Thereafter, the substrate processing unit 17 supplies the processing fluid from the sub-supply line 51 to the processing space via the second supply header 37, while discharging the processing fluid supplied to the processing space to the discharge line 52 via the discharge header 38 (a circulation process described below).

[0060] This forms a laminar flow of the processing fluid in a predetermined direction around the wafer W in the processing space. This laminar flow of the processing fluid flows, for example, from the second supply header 37 above the wafer W, along the upper surface of the wafer W, toward the top of the opening 34. Furthermore, the laminar flow of the processing fluid turns downward above the opening 34, passes near the opening 34, and flows toward the discharge header 38.

[0061] Next, the configuration of the supply lines and discharge lines connected to the substrate processing unit 17 will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of the configuration of the supply lines and discharge lines connected to the substrate processing unit 17.

[0062] 4, the supply line for the processing fluid according to the embodiment includes a main supply line 50 and a sub-supply line 51. One end of the main supply line 50 is connected to a fluid supply source 100 that supplies the processing fluid, and the other end is connected to a first supply header 36 (see FIG. 3) inside the processing vessel 31.

[0063] The fluid supply source 100 is, for example, a tank that stores CO 2 , which is an example of a processing fluid. The processing fluid stored in the fluid supply source 100 is supplied to the main supply line 50 and the sub-supply line 51.

[0064] The main supply line 50 is provided with, in order from upstream to downstream, a valve 101, a junction 50a, a heater 102, a pressure sensor 103, a branching section 50b, an orifice 104, a temperature sensor 105, a branching section 50c, a valve 106, and a pressure sensor 107.

[0065] Furthermore, in the main supply line 50, a temperature sensor 108, a branching section 50d, a valve 109, and a filter 110 are provided in this order from the pressure sensor 107 toward the downstream side. The branching section 50d is an example of a branch point. Note that the terms upstream and downstream in this disclosure are based on the flow direction of the processing fluid.

[0066] Valve 101 is a valve that adjusts the on / off state of the supply of processing fluid from fluid supply source 100, and when open, allows supercritical fluid to flow into the downstream main supply line 50, and when closed, does not allow supercritical fluid to flow into the downstream main supply line 50.

[0067] For example, when the valve 101 is in an open state, the processing fluid that has been pressurized to about 19 to 20 MPa and brought to a supercritical state is supplied from the fluid supply source 100 to the main supply line 50 via the valve 101 .

[0068] The heater 102 heats the processing fluid flowing downstream of the valve 101. The pressure sensor 103 detects the pressure of the processing fluid flowing through the main supply line 50 between the heater 102 and the branching portion 50b.

[0069] Orifice 104 adjusts the pressure of the processing fluid supplied from fluid supply source 100. Temperature sensor 105 detects the temperature of the processing fluid flowing through main supply line 50 between orifice 104 and branch portion 50c. Valve 106 is a valve that adjusts the supply of processing fluid to branch portion 50d of main supply line 50 on and off.

[0070] The pressure sensor 107 detects the pressure of the processing fluid flowing through the main supply line 50 between the valve 106 and the temperature sensor 108. The temperature sensor 108 detects the temperature of the processing fluid flowing through the main supply line 50 between the pressure sensor 107 and the branch point 50d.

[0071] The valve 109 is an example of a second on-off valve, and is a valve that adjusts the supply of the processing fluid to the first supply header 36 of the substrate processing unit 17 on and off. The filter 110 removes foreign matter contained in the processing fluid flowing through the main supply line 50.

[0072] The main supply line 50 is connected to a purge line 55 at a junction 50a. One end of the purge line 55 is connected to a purge gas supply source 126, and the other end is connected to the main supply line 50 at the junction 50a.

[0073] Purge gas supply source 126 is, for example, a tank that stores purge gas. The purge gas is, for example, an inert gas such as nitrogen gas. A check valve 127 and a valve 128 are provided in the middle of purge line 55, in this order from the purge gas supply source 126 side toward main supply line 50 side.

[0074] The purge gas stored in the purge gas supply source 126 is supplied to the processing space of the substrate processing unit 17 via the purge line 55 and the main supply line 50, for example, while the supply of processing fluid to the processing space of the substrate processing unit 17 is stopped.

[0075] Furthermore, the main supply line 50 is connected to a branch line 56 at a branch point 50b. One end of the branch line 56 is connected to the branch point 50b of the main supply line 50, and the other end is connected to the exhaust section EXH. A valve 129 is provided midway through the branch line 56.

[0076] The secondary supply line 51 is connected to a branch point 50c of the main supply line 50 on the upstream side, and branches into a branch supply line 51b and a branch supply line 51c at a branch point 51a on the downstream side, and is connected to a second supply header 37 (see Figure 3) inside the processing vessel 31.

[0077] The sub-supply line 51 is provided with a valve 111, a filter 112, and a branch 51a in this order from the branch 50c toward the downstream side. The valve 111 controls the on / off state of the supply of the processing fluid to the second supply header 37 of the substrate processing unit 17. The filter 112 removes foreign matter contained in the processing fluid flowing through the sub-supply line 51.

[0078] The branch supply lines 51b and 51c are provided with temperature sensors 113 and 114, respectively. The temperature sensors 113 and 114 detect the temperature of the processing fluid flowing through the sub-supply line 51 in the branch supply lines 51b and 51c.

[0079] The processing vessel 31 of the substrate processing unit 17 is provided with a temperature sensor 115. The temperature sensor 115 detects the temperature of the processing space inside the processing vessel 31.

[0080] The discharge line 52 is connected at one end to the discharge header 38 (see FIG. 3) inside the treatment vessel 31, and at the other end to the exhaust section EXH.

[0081] The discharge line 52 branches into a branch discharge line 52a and a branch discharge line 52b on the upstream side connected to the discharge header 38. The branch discharge line 52a and the branch discharge line 52b join at a joining point 52c on the downstream side.

[0082] A temperature sensor 116 and a pressure sensor 117 are provided in branch discharge line 52a, in that order from upstream to downstream. In branch discharge line 52a, temperature sensor 116 detects the temperature of the processing fluid flowing through discharge line 52. In branch discharge line 52a, pressure sensor 117 detects the pressure of the processing fluid flowing through discharge line 52.

[0083] Discharge line 52 is provided with, in this order from junction 52c toward the downstream side, a valve 118, junction 52d, pressure adjustment valve 119, temperature sensor 120, pressure sensor 121, and valve 122. Junction 52d is an example of a junction point.

[0084] The valve 118 is an example of a first on-off valve, and is a valve that adjusts the discharge of the processing fluid from the substrate processing unit 17 on and off.

[0085] The pressure regulating valve 119 is a valve that regulates the pressure of the processing fluid flowing through the exhaust line 52, and is configured by, for example, a back pressure valve. The aperture of the pressure regulating valve 119 can be adaptively adjusted under the control of the control device 4 in accordance with the pressure in the processing space of the substrate processing unit 17. The aperture of the pressure regulating valve 119 can be adjusted by, for example, PID (Proportional-Integral-Differential) control.

[0086] The temperature sensor 120 detects the temperature of the process fluid flowing through the discharge line 52 downstream of the pressure regulating valve 119. The pressure sensor 121 detects the pressure of the process fluid flowing through the discharge line 52 downstream of the pressure regulating valve 119.

[0087] The valve 122 is a valve that adjusts the on / off state of the discharge of the processing fluid to the exhaust section EXH. When the processing fluid is to be discharged to the exhaust section EXH, the valve 122 is opened, and when the processing fluid is not to be discharged, the valve 122 is closed.

[0088] In the embodiment, a bypass line 53 is connected between the main supply line 50 and the discharge line 52. One end of the bypass line 53 is connected to a branching portion 50d of the main supply line 50, and the other end is connected to a junction 52d of the discharge line 52.

[0089] In the bypass line 53, an orifice 123, a branching portion 53a, and a valve 124 are provided in this order from the branching portion 50d toward the confluence portion 52d. The orifice 123 adjusts the pressure of the processing fluid flowing through the bypass line 53. The valve 124 is a valve that adjusts the flow of the processing fluid in the bypass line 53 between on and off.

[0090] The bypass line 53 is connected to a branch line 54 at a branch point 53a. One end of the branch line 54 is connected to the branch point 53a of the bypass line 53, and the other end is connected to the exhaust section EXH. A valve 125 is provided midway through the branch line 54.

[0091] <Embodiment> Next, details of the substrate processing according to the embodiment will be described with reference to Fig. 5 to Fig. 11. Fig. 5 is a flowchart showing an example of the procedure of each process executed by the substrate processing unit 17 according to the embodiment, and Fig. 6 is a diagram showing an example of the change in pressure in the processing space over time during the pressure increase process, the holding process, the circulation process, and the depressurization process according to the embodiment.

[0092] Each processing procedure shown in Figure 5 is executed by the control unit 19 (see Figure 1) reading out a program stored in the memory unit 20 (see Figure 1) of the control device 4 (see Figure 1) and controlling the substrate processing unit 17 based on the read instructions.

[0093] At the start of the loading process in step S101, all of the valves 101, 106, 109, 111, 118, 122, 124, 125, 128, and 129 and the pressure adjustment valve 119 shown in FIG. 4 are in a closed state.

[0094] 5, in the substrate processing unit 17, first, a loading process is performed in which the wafer W on which the additive A is puddled is loaded into the processing space (step S101). In this loading process, the wafer W on which the additive A is puddled is first held by the holding plate 32 (see FIG. 3). Thereafter, the holding plate 32 and the lid member 33 are housed inside the processing vessel 31 together with the wafer W, and the opening 34 is sealed by the lid member 33.

[0095] Next, a pressure increase process is performed in the substrate processing unit 17 (step S102). In this pressure increase process, the valves 101, 106, and 109 of the main supply line 50 are opened as shown in Fig. 7. Fig. 7 is a diagram showing an example of the operation of the pressure increase process according to the embodiment.

[0096] 7, the processing fluid in a supercritical state is supplied to the processing space from the fluid supply source 100 via the main supply line 50. During this pressurization process, the valve 111 of the sub-supply line 51, the valves 118 and 122 and the pressure adjustment valve 119 of the exhaust line 52, the valve 124 of the bypass line 53, and the valve 125 of the branch line 54 are maintained in a closed state.

[0097] Therefore, the pressure in the processing space increases when the processing fluid is supplied to the processing space in the substrate processing unit 17. Specifically, as shown in Fig. 6, a pressure increase process is performed from time T1 to time T2, and the pressure in the processing space increases from atmospheric pressure to processing pressure P1.

[0098] The processing pressure P1 is a pressure exceeding the critical pressure Ps (approximately 7.2 MPa) at which the processing fluid CO2 becomes supercritical, and is, for example, approximately 18 MPa. By this pressure increase process, the processing fluid in the processing space changes phase to a supercritical state and mixes with the additive A puddled on the upper surface of the wafer W.

[0099] In the pressurization process, the processing fluid is supplied to the lower surface of the wafer W from a first supply header 36 (see FIG. 3) disposed below the wafer W. This prevents the additive A piled on the upper surface of the wafer W from spilling due to the processing fluid hitting the upper surface of the wafer W.

[0100] 7 to 12, for ease of understanding, illustrations are omitted for the main supply line 50, the sub-supply line 51, the discharge line 52, the bypass line 53, the branch line 54, and the multiple valves provided on each of these lines. In addition, in FIGS. 7 to 12, valves in an open state are marked with an "O," and valves in a closed state are marked with a "C."

[0101] 5, a holding process is performed in the substrate processing unit 17 (step S103). In this holding process, the processing space in the substrate processing unit 17 is isolated, and the pressure in the processing space is held at processing pressure P1 from time T2 to time T3 (for example, several hours) as shown in FIG. 6. This allows the wafer W to undergo a given substrate process in the processing space.

[0102] Then, in the retention process according to the embodiment, as shown in FIG. 8, the valve 109 of the main supply line 50 is changed to a closed state, and the pressure adjustment valve 119 of the discharge line 52 is changed to a PID control state (referred to as "PID" in the following drawings).

[0103] Furthermore, in the holding process, the valve 122 of the discharge line 52 and the valve 124 of the bypass line 53 are changed to an open state. Figure 8 is a diagram showing an example of the operation of the holding process according to the embodiment.

[0104] As a result, as shown by the thick dashed line in FIG. 8, the processing fluid in a supercritical state is supplied from the fluid supply source 100 via the main supply line 50 to the bypass line 53 and the discharge line 52 downstream of the junction 52d.

[0105] During this holding process, the valves 101 and 106 of the main supply line 50 are maintained in an open state, and the valve 111 of the secondary supply line 51, the valve 118 of the discharge line 52, and the valve 125 of the branch line 54 are maintained in a closed state.

[0106] As shown in FIG. 8, in the holding process according to the embodiment, all of the valves 109, 111, and 118 isolating the processing vessel 31 of the substrate processing unit 17 are in contact with a supercritical fluid flowing at a high pressure (e.g., 18 MPa) on the side opposite to the side connected to the processing vessel 31.

[0107] In other words, in the embodiment, by circulating the supercritical fluid through the bypass line 53, in addition to the valves 109 and 111, the valve 118 of the exhaust line 52 also comes into contact with the supercritical fluid flowing at high pressure on the side opposite to the side connected to the processing vessel 31.

[0108] This makes it possible to prevent leakage of the supercritical processing fluid held in the processing vessel 31 even if a malfunction occurs in the valves 109, 111, and 118 isolating the processing vessel 31 due to, for example, a foreign object being caught in the valves 109, 111, and 118. This is because there is almost no pressure difference that could cause leakage on both sides of all of the valves 109, 111, and 118 (especially valve 118) isolating the processing vessel 31.

[0109] Therefore, according to the embodiment, the processing fluid in a supercritical state can be stably confined within the processing vessel 31 for a long period of time.

[0110] Furthermore, in the embodiment, the processing fluid in a supercritical state can be stably contained in the processing vessel 31 for a long period of time while suppressing replenishment of the processing fluid, and therefore the concentration of the additive A in the processing vessel 31 can be stably maintained. Therefore, according to the embodiment, a given substrate processing can be stably performed.

[0111] In the embodiment, the control unit 19 may detect the pressure in the processing space during the holding process using the pressure sensor 117 (see FIG. 4) and perform PID control of the pressure adjustment valve 119 according to the pressure in the processing space.

[0112] For example, when the pressure in the processing space tends to decrease, the control unit 19 may reduce the opening of the pressure adjustment valve 119 to increase the pressure upstream of the pressure adjustment valve 119 (i.e., the side opposite to the side where the valves 109, 111, and 118 connect to the processing vessel 31).

[0113] This allows the processing fluid in a supercritical state to be confined in the processing vessel 31 more stably for a long period of time.

[0114] Furthermore, in the holding process according to the embodiment, the valve 109 provided in the main supply line 50 may be periodically opened and closed. This allows the pressure in the processing space to easily return to the processing pressure P1 even when the pressure in the processing space tends to decrease.

[0115] Therefore, according to the embodiment, the processing fluid in a supercritical state can be more stably confined within the processing vessel 31 for a long period of time.

[0116] In addition, in an embodiment, the fluid supply source 100 that supplies the processing fluid may have a pressure reduction mechanism that can reduce the pressure of the processing fluid supplied to the bypass line 53, etc. to a given pressure (for example, approximately 18.5 MPa) during the retention process.

[0117] This reduces the amount of processing fluid discharged into the exhaust section EXH during the retention process according to the embodiment, thereby reducing the amount of processing fluid used and, therefore, the running costs of the retention process according to the embodiment can be reduced.

[0118] Note that the present disclosure is not limited to the case where the pressure of the processing fluid supplied to the bypass line 53, etc. is reduced by the pressure reduction mechanism of the fluid supply source 100. For example, the valves 111 and 106 may each be replaced with pressure reduction valves that can reduce the pressure on the downstream side, and the pressure of the processing fluid supplied to the bypass line 53, etc. may be reduced using these two pressure reduction valves during the retention process.

[0119] This also reduces the amount of processing fluid discharged into the exhaust section EXH during the retention process according to the embodiment, thereby reducing the amount of processing fluid used and, therefore, the running costs of the retention process according to the embodiment can be reduced.

[0120] Returning to the description of Fig. 5, next, a circulation process is performed in the substrate processing unit 17 (step S104). In this circulation process, as shown in Fig. 9, the valve 111 of the sub-supply line 51 and the valve 118 of the discharge line 52 are changed to an open state, and the valve 106 of the main supply line 50 and the valve 124 of the bypass line 53 are changed to a closed state. Fig. 9 is a diagram showing an example of the operation of the circulation process according to the embodiment.

[0121] As a result, a laminar flow of the processing fluid is formed in the processing space from the second supply header 37 (see FIG. 3) above the wafer W, along the upper surface of the wafer W, and toward the discharge header 38 (see FIG. 3).

[0122] During this circulation process, valve 101 of main supply line 50 and valve 122 of discharge line 52 are maintained in an open state, and valve 109 of main supply line 50 and valve 125 of branch line 54 are maintained in a closed state. Also, during this circulation process, pressure adjustment valve 119 of discharge line 52 is maintained in a PID controlled state.

[0123] In this flow treatment, the pressure in the treatment space is maintained at a pressure that maintains the supercritical state of the treatment fluid. Specifically, as shown in Fig. 6, from time T3 to time T4 during which the flow treatment is performed, the pressure in the treatment space is maintained at a given pressure P2 (for example, about 16 MPa).

[0124] By this circulation process, the processing fluid containing additive A that has been remaining on the upper surface of the wafer W is replaced with a processing fluid that does not contain additive A. The circulation process is carried out until the additive A remaining in the processing space is sufficiently reduced, for example, until the concentration of additive A in the processing space reaches 0% to several percent.

[0125] In the embodiment, the control unit 19 may detect the pressure in the processing space during the circulation process using the pressure sensor 117 (see FIG. 4) and perform PID control of the pressure adjustment valve 119 according to the pressure in the processing space. This allows the pressure of the processing fluid in the processing container 31 to be stably maintained.

[0126] In the example of FIG. 6, the processing fluid is circulated so that the pressure in the processing space is constant during the flow processing, but the pressure in the processing space does not necessarily have to be constant during the flow processing.

[0127] Furthermore, in the example of FIG. 6, the given pressure P2 is shown as being lower than the processing pressure P1, but the present disclosure is not limited to such an example, and the pressure P2 may be approximately equal to the processing pressure P1, or the pressure P2 may be higher than the processing pressure P1.

[0128] Returning to the description of Fig. 5, next, a depressurization process is performed in the substrate processing unit 17 (step S105). In this depressurization process, as shown in Fig. 10, the valve 101 of the main supply line 50 and the valve 111 of the sub-supply line 51 are changed to a closed state, and the pressure adjustment valve 119 of the exhaust line 52 is changed to a fully open state. Fig. 10 is a diagram showing an example of the operation of the depressurization process according to the embodiment.

[0129] This stops the supply of the processing fluid to the processing space. Meanwhile, because the valves 118 and 122 of the exhaust line 52 and the pressure control valve 119 are open, the processing fluid in the processing space is discharged to the outside through the exhaust line 52. This reduces the pressure in the processing space.

[0130] During this decompression process, the valves 118 and 122 on the discharge line are maintained in an open state, and the valves 106 and 109 on the main supply line 50, the valve 124 on the bypass line 53, and the valve 125 on the branch line 54 are maintained in a closed state.

[0131] This depressurization process is performed until the pressure in the processing space drops to atmospheric pressure. Specifically, as shown in Figure 6, the depressurization process is performed from time T4 to time T5, and the pressure in the processing space drops from processing pressure P1 to atmospheric pressure.

[0132] In addition, in an embodiment, after the pressure in the processing space is reduced to a given pressure (for example, about 3 MPa) and the processing fluid in the processing space changes phase from a supercritical state to a gaseous state, the processing fluid may also be discharged via the bypass line 53 and the branch line 54.

[0133] Specifically, the valve 124 of the bypass line 53 and the valve 125 of the branch line 54 are changed to an open state, as shown in Fig. 11. Fig. 11 is a diagram showing an example of the operation of the depressurization process according to the embodiment.

[0134] As a result, the processing fluid in the processing space is discharged to the outside through the bypass line 53 and the branch line 54 in addition to the discharge line 52, so that the decompression process can be completed quickly.

[0135] Returning to the explanation of FIG. 5, next, in the substrate processing unit 17, an unloading process is performed (step S106). In this unloading process, the holding plate 32 and the lid member 33 move, and the wafer W that has been dried is unloaded from the processing space. When this unloading process is completed, the series of substrate processing steps for one wafer W is completed.

[0136] <Another embodiment> Next, substrate processing according to another embodiment will be described with reference to Fig. 12. In the following embodiment, the same components as those in the embodiment will be designated by the same reference numerals, and redundant description will be omitted.

[0137] In this another embodiment, each processing procedure for substrate processing is as shown in Fig. 5, and the change in pressure in the processing space over time during each processing procedure is as shown in Fig. 6. Furthermore, the loading process (step S101) and the pressure increase process (step S102) according to this another embodiment are similar to those in the above embodiment, and therefore detailed description thereof will be omitted.

[0138] In the holding process (step S103) according to another embodiment, similarly to the above-described embodiment, the processing space in the substrate processing unit 17 is isolated, and the pressure in the processing space is held at processing pressure P1 from time T2 to time T3, as shown in Fig. 6. This allows the wafer W to undergo a given substrate process in the processing space.

[0139] In the holding process according to another embodiment, the valve 109 of the main supply line 50 is periodically opened and closed, as shown in Fig. 12. Fig. 12 is a diagram showing an example of the operation of the holding process according to another embodiment.

[0140] During this holding process, valves 101 and 106 of main supply line 50 are maintained in an open state. Also, during this holding process, valve 111 of sub-supply line 51, valves 118 and 122 and pressure adjustment valve 119 of discharge line 52, valve 124 of bypass line 53, and valve 125 of branch line 54 are maintained in a closed state.

[0141] As a result, as shown by the thick dashed line in Figure 12, high-pressure processing fluid is periodically supplied from the fluid supply source 100, so even if the pressure in the processing space tends to decrease, the pressure in the processing space can be easily restored to processing pressure P1.

[0142] Therefore, according to the other embodiment, the processing fluid in a supercritical state can be stably contained for a long period of time within the processing vessel 31. Note that the circulation process (step S104), the decompression process (step S105), and the carry-out process (step S106) according to the other embodiment are similar to those in the above embodiment, and therefore detailed description thereof will be omitted.

[0143] The substrate processing method according to the embodiment is a substrate processing method for a substrate processing apparatus (substrate processing system 1) that processes a substrate (wafer W) by bringing it into contact with a processing fluid in a supercritical state. The substrate processing apparatus (substrate processing system 1) includes a processing vessel 31, a main supply line 50, a discharge line 52, and a bypass line 53. The processing vessel 31 has a processing space capable of accommodating a substrate (wafer W). The main supply line 50 supplies the processing fluid to the processing space. The discharge line 52 has a first on-off valve (valve 118) and discharges the processing fluid from the processing space. The bypass line 53 branches from the main supply line 50 at a branch point (branch portion 50d) and joins the discharge line 52 at a junction point (junction portion 52d) downstream of the first on-off valve (valve 118). The substrate processing method according to one aspect of the present disclosure also includes a pressurization step (step S102) and a holding step (step S103). In the pressurization step (step S102), with a substrate (wafer W) accommodated in the processing space, a processing fluid is supplied to the processing space from the main supply line 50, thereby increasing the pressure in the processing space to a given processing pressure P1. In the maintaining step (step S103), after the pressurization step (step S102), the processing fluid is circulated through the bypass line 53 with the first on-off valve (valve 118) closed, thereby maintaining the pressure in the processing space at the processing pressure P1. This allows the processing fluid in a supercritical state to be stably contained within the processing vessel 31 for a long period of time.

[0144] In the substrate processing method according to the embodiment, the main supply line 50 includes a second on-off valve (valve 109) provided downstream of the branch point (branch portion 50d), which allows the processing fluid to flow through the bypass line 53 even when the supply of the processing fluid from the main supply line 50 to the processing space is stopped.

[0145] In the substrate processing method according to the embodiment, the second on-off valve (valve 109) is periodically opened and closed in the holding step (step S103), which allows the processing fluid in a supercritical state to be contained in the processing vessel 31 more stably for a long period of time.

[0146] In the substrate processing method according to the embodiment, the substrate processing apparatus (substrate processing system 1) further includes a sub-supply line 51 that supplies a processing fluid to the processing space. The main supply line 50 supplies the processing fluid toward the underside of the substrate (wafer W) held horizontally in the processing vessel 31, and the sub-supply line 51 supplies the processing fluid horizontally toward above the substrate (wafer W) held horizontally in the processing vessel 31. This prevents the additive A puddled on the upper surface of the wafer W from spilling due to the processing fluid hitting the upper surface of the wafer W, and also allows the processing fluid containing additive A that has accumulated on the upper surface of the wafer W to be efficiently replaced with a processing fluid that does not contain additive A.

[0147] In the substrate processing method according to the embodiment, the substrate processing apparatus (substrate processing system 1) further includes a sub-supply line 51 that supplies a processing fluid to the processing space. The main supply line 50 is provided upstream of the branch point (branch portion 50d) and includes a first pressure reducing valve that can reduce the pressure on the downstream side. The sub-supply line 51 also includes a second pressure reducing valve that can reduce the pressure on the downstream side. In the holding step (step S103), the pressure of the processing fluid downstream of the first and second pressure reducing valves is reduced to a given pressure. This reduces the running costs of the holding process.

[0148] In the substrate processing method according to the embodiment, the substrate processing apparatus (substrate processing system 1) includes a fluid supply source 100 that supplies a processing fluid to the processing container 31. The fluid supply source 100 has a pressure reduction mechanism that can reduce the pressure of the processing fluid to be supplied. In the holding step (step S103), the pressure of the processing fluid supplied from the fluid supply source 100 is reduced to a given pressure. This reduces the running cost of the holding process.

[0149] Another embodiment of the substrate processing method is a substrate processing method for a substrate processing apparatus (substrate processing system 1) that processes a substrate (wafer W) by contacting the substrate with a processing fluid in a supercritical state. The substrate processing apparatus (substrate processing system 1) includes a processing vessel 31 and a main supply line 50. The processing vessel 31 has a processing space capable of accommodating a substrate (wafer W). The main supply line 50 has a second on-off valve (valve 109) and supplies the processing fluid to the processing space. The substrate processing method according to one embodiment of the present disclosure also includes a pressurization step (step S102) and a holding step (step S103). In the pressurization step (step S102), the pressure in the processing space is increased to a given processing pressure P1 by supplying the processing fluid from the main supply line 50 to the processing space while the substrate (wafer W) is accommodated in the processing space. In the pressure maintaining step (step S103), after the pressure increasing step (step S102), the pressure in the processing space is maintained at the processing pressure P1 by periodically opening and closing the second on-off valve (valve 109). This allows the processing fluid in a supercritical state to be stably contained within the processing vessel 31 for a long period of time.

[0150] In the substrate processing method according to each embodiment, the holding step (step S103) fills the processing vessel 31 with a processing fluid containing an additive A, and the additive A contains a low-hydric alcohol. This allows a given substrate processing to be performed.

[0151] In the substrate processing method according to each embodiment, the processing fluid is CO. This allows a given substrate process to be performed.

[0152] The substrate processing apparatus (substrate processing system 1) according to the embodiment includes a processing vessel 31, a main supply line 50, a discharge line 52, a bypass line 53, and a controller 19. The processing vessel 31 has a processing space capable of accommodating a substrate (wafer W). The main supply line 50 supplies a processing fluid in a supercritical state to the processing space. The discharge line 52 has a first on-off valve (valve 118) and discharges the processing fluid from the processing space. The bypass line 53 branches from the main supply line 50 at a branch point (branch point 50d) and joins the discharge line 52 at a junction point (junction point 52d) downstream of the first on-off valve (valve 118). The controller 19 controls each component. With the substrate (wafer W) accommodated in the processing space, the controller 19 supplies the processing fluid from the main supply line 50 to the processing space, thereby increasing the pressure in the processing space to a given processing pressure P1. Furthermore, after increasing the pressure in the processing space to processing pressure P1, the control unit 19 maintains the pressure in the processing space at processing pressure P1 while circulating the processing fluid through the bypass line 53 with the first on-off valve (valve 118) closed. This allows the processing fluid in a supercritical state to be stably contained within the processing vessel 31 for a long period of time.

[0153] In the substrate processing apparatus (substrate processing system 1) according to the embodiment, the main supply line 50 has a second on-off valve (valve 109) provided downstream of the branch point (branch portion 50d), which allows the processing fluid to flow through the bypass line 53 even when the supply of the processing fluid from the main supply line 50 to the processing space is stopped.

[0154] The substrate processing apparatus (substrate processing system 1) according to each embodiment further includes a sub-supply line 51 that supplies a processing fluid to the processing space. The main supply line 50 supplies the processing fluid toward the underside of the substrate (wafer W) held horizontally in the processing vessel 31, and the sub-supply line 51 supplies the processing fluid horizontally toward above the substrate (wafer W) held horizontally in the processing vessel 31. This prevents the additive A puddled on the upper surface of the wafer W from spilling due to the processing fluid hitting the upper surface of the wafer W, and also allows the processing fluid containing additive A that has accumulated on the upper surface of the wafer W to be efficiently replaced with a processing fluid that does not contain additive A.

[0155] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0156] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0157] W wafer (an example of a substrate) 1. Substrate processing system (an example of a substrate processing device) 16. Supply Processing Unit 17 Substrate Processing Unit 19 Control Unit 31 Processing vessel 50 Main Supply Line 50d Branching point (example of branching point) 51 Sub-supply line 52 Discharge line 52d Confluence (example of a confluence) 53 Bypass Line 100 Fluid Source 109 Valve (Example of second on-off valve) 118 Valve (Example of first shut-off valve) A. Additives P1 Processing pressure

Claims

1. A substrate processing method for a substrate processing apparatus that processes a substrate by contacting it with a processing fluid in a supercritical state, comprising: The substrate processing apparatus includes: a processing vessel having a processing space capable of accommodating the substrate; a main supply line having a second on-off valve for supplying the processing fluid to the processing space; a discharge line having a first on-off valve and configured to discharge the processing fluid from the processing space; a bypass line that branches off from the main supply line at a branch point upstream of the second on-off valve and joins with the discharge line at a joining point downstream of the first on-off valve; Equipped with a pressure increasing step of increasing the pressure in the processing space to a critical pressure or higher by supplying the processing fluid from the main supply line to the processing space while the substrate is accommodated in the processing space; a holding step of circulating the treatment fluid through the bypass line with the second on-off valve and the first on-off valve closed after the pressurization step; A substrate processing method comprising:

2. the discharge line has a back pressure valve; In the maintaining step, the back pressure valve is PID controlled while the processing fluid is circulated through the bypass line, and the pressure in the processing space is maintained at or above the critical pressure. The substrate processing method according to claim 1 .

3. In the holding step, the second on-off valve is periodically opened and closed. The substrate processing method according to claim 2 .

4. The substrate processing apparatus includes: a secondary supply line for supplying the processing fluid to the processing space; the main supply line supplies the processing fluid toward a lower surface of the substrate held horizontally in the processing chamber; The sub-supply line supplies the processing fluid horizontally above the substrate held horizontally in the processing vessel. The substrate processing method according to any one of claims 1 to 3.

5. The substrate processing apparatus includes: a secondary supply line for supplying the processing fluid to the processing space; the main supply line has a first pressure reducing valve that is provided upstream of the branch point and is capable of reducing pressure downstream, the auxiliary supply line has a second pressure reducing valve capable of reducing the pressure on the downstream side; In the maintaining step, the pressure of the processing fluid downstream of the first pressure reducing valve and the second pressure reducing valve is reduced to a given pressure. The substrate processing method according to any one of claims 1 to 3.

6. the substrate processing apparatus includes a fluid supply source that supplies the processing fluid to the processing vessel; the fluid supply source has a pressure reducing mechanism capable of reducing the pressure of the processing fluid to be supplied, In the maintaining step, the pressure of the processing fluid supplied from the fluid supply source is reduced to a given pressure. The substrate processing method according to any one of claims 1 to 3.

7. The holding step includes filling the processing vessel with the processing fluid containing the additive; The additive includes a low-hydric alcohol. The substrate processing method according to any one of claims 1 to 3.

8. The treatment fluid is CO ２ is The substrate processing method according to any one of claims 1 to 3.

9. a processing vessel having a processing space capable of accommodating a substrate; a main supply line having a second on-off valve and supplying a processing fluid in a supercritical state to the processing space; a discharge line having a first on-off valve and configured to discharge the processing fluid from the processing space; a bypass line that branches off from the main supply line at a branch point upstream of the second on-off valve and joins with the discharge line at a joining point downstream of the first on-off valve; a control unit that controls each unit; Equipped with The control unit supplying the processing fluid from the main supply line to the processing space while the substrate is accommodated in the processing space, thereby increasing the pressure in the processing space to a critical pressure or higher; After the pressure in the processing space is increased to the critical pressure or higher, the processing fluid is circulated through the bypass line with the second on-off valve and the first on-off valve closed. Substrate processing equipment.

10. the discharge line has a back pressure valve; When the processing fluid is circulated, the control unit performs PID control of the back pressure valve while circulating the processing fluid through the bypass line, thereby maintaining the pressure in the processing space at or above the critical pressure. The substrate processing apparatus according to claim 9 .

11. a secondary supply line for supplying the processing fluid to the processing space; the main supply line supplies the processing fluid toward a lower surface of the substrate held horizontally in the processing chamber; The sub-supply line supplies the processing fluid horizontally above the substrate held horizontally in the processing vessel. The substrate processing apparatus according to claim 9 or 10.

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