Substrate processing device and substrate processing method

Abstract

The purpose of this invention is to reduce impurities present on the surface of a processed substrate. The substrate processing apparatus of the present invention includes: a processing container having an opening for moving a substrate in and out; a cover that is movable and blocks the opening of the processing container; a cover moving mechanism that moves the cover between a closed position that blocks the opening and an open position that opens the opening; a substrate holding portion that holds the substrate horizontally with its surface facing upward within the processing container; and a fluid supply mechanism that can supply a supercritical processing fluid and a gaseous fluid composed of the same substance as the supercritical processing fluid to the processing container. The apparatus also includes at least one supply line and a flow control device, and a control unit that controls the fluid supply mechanism as follows: in a first state where the substrate is held in the substrate holding portion and the cover is in the closed position, the supercritical processing fluid is supplied to the processing container; and in a second state where the cover is in the open position, the gaseous fluid is supplied to the processing container.

Description

Technical Field

[0001] This invention relates to a substrate processing apparatus and a substrate processing method. Prior Technology

[0002] In the manufacture of semiconductor devices in which integrated circuits are formed on the surface of substrates such as semiconductor wafers, liquid treatments such as chemical cleaning or wet etching are performed. In order to more reliably prevent the collapse of increasingly miniaturized patterns in recent years, drying methods that utilize supercritical processing fluids in the final step of liquid treatment, namely the drying step, are used in recent years (for example, see Patent Document 1). [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-074103 Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] This invention provides a technique for reducing impurities present on the surface of a processed substrate. [Methods for solving problems]

[0006] One embodiment of the present invention provides a substrate processing apparatus for drying a substrate with liquid adhering to its surface using supercritical drying technology. The apparatus includes: a processing container having an opening for moving the substrate into or out of the processing container; a cover that closes the opening of the processing container and is movable; a cover moving mechanism that moves the cover between a closed position (closing the opening) and an open position (opening the opening); a substrate holding portion that horizontally holds the substrate with its surface facing upward within the processing container; and a fluid supply mechanism that supplies supercritical processing fluid and fluid from the supercritical state... A gaseous fluid of the same composition as the processing fluid is supplied to the processing container, and the container includes at least one supply line and a flow control device; and a control unit that controls the fluid supply mechanism as follows: in a first state where the substrate is held in the processing container by the substrate holding part and the cover is in the closed position, the supercritical processing fluid is supplied to the processing container; and in a second state where the substrate is not held in the processing container by the substrate holding part and the cover is in the open position, the gaseous fluid is supplied to the processing container. [Invention Effects]

[0007] By implementing the above-described embodiments, impurities present on the surface of the processed substrate can be reduced. Simple Explanation of the Diagram

[0008] Figure 1 is a schematic longitudinal cross-sectional view of a supercritical drying unit in one embodiment of a substrate processing apparatus. Figure 2 is a schematic cross-sectional view of the supercritical drying unit along line II-II in Figure 1. Figure 3 is a schematic longitudinal cross-sectional view of a supercritical drying unit in which the rinsing step is performed. Figure 4 is a diagram of the piping system used for supplying / discharging fluids into the processing container. Figure 5A is a diagram illustrating the function of one step in the supercritical drying process. Figure 5B shows the function of one step in the supercritical drying process. Figure 5C shows the function of one step in the supercritical drying process. Figure 5D is a diagram illustrating the function of one step in the supercritical drying process. Figure 5E shows the function of one step in the supercritical drying process. Figure 6 is a schematic side view of one configuration example of the housing of a supercritical drying unit. Figure 7 is a schematic longitudinal cross-sectional view showing the other components of the supercritical drying unit. Implementation

[0009] Referring to Figures 1 to 4, the configuration of a supercritical drying apparatus, as one embodiment of a substrate processing apparatus, is described. The supercritical drying apparatus can be used to perform supercritical drying processing on a substrate W whose surface is coated with a liquid film (e.g., IPA (isopropyl alcohol)) using a supercritical processing fluid (e.g., carbon dioxide). The substrate W is, for example, a semiconductor wafer, but can also be other types of substrates used in the field of semiconductor device manufacturing (glass substrates, ceramic substrates, etc.). Because supercritical drying technology does not subject the pattern to surface tension that could cause pattern collapse, it is suitable for drying substrates with small, high aspect ratio patterns.

[0010] To facilitate the explanation of directions and positions, the XYZ rectangular coordinate system is established below, and this coordinate system will be used as a reference when necessary. Also, note that the X direction is also called the forward / backward direction (the positive X direction is forward), the Y direction is also called the left / right direction (the positive Y direction is left), and the Z direction is also called the up / down direction (the positive Y direction is up).

[0011] The supercritical drying apparatus includes a processing unit 10. Supercritical drying is performed inside the processing unit 10. The processing unit 10 has a processing container 11 and a substrate holding tray 12 (hereinafter referred to as "tray 12") that holds the substrate W inside the processing container 11.

[0012] The tray 12 has a cover 13 that closes an opening 11C on the side wall of the processing container 11, and a substrate holding portion 14 integrally connected to the cover 13 and extending horizontally. The substrate holding portion 14 has a plate 15 and a plurality of support pins 16 provided on the top surface of the plate 15. The substrate W is placed horizontally on the support pins 16 with its surface (the surface where elements or patterns are formed) facing upward. When the substrate W is placed on the support pins 16, a gap 17 is formed between the top surface of the plate 15 and the bottom surface (back surface) of the substrate W.

[0013] The plate 15 is, for example, rectangular or square. The area of ​​the plate 15 is larger than that of the substrate W. When the substrate W is placed in a predetermined position on the substrate holding part 14, the plate 15 is completely covered by the substrate W when viewed from directly below.

[0014] A plurality of through holes 18 are formed in the plate body 15, extending vertically through the plate body 15. The plurality of through holes 18 serve to allow the processing fluid supplied to the lower space of the plate body 15 to flow into the upper space of the plate body 15. Several of the plurality of through holes 18 also serve to allow the lifting pins (indicated by reference numeral 300 in the lower part of FIG. 6) that transfer the substrate W between the substrate holding part 14 and the substrate transport mechanism (not shown) outside the processing unit 10 to pass through, but a detailed description of this point is omitted in this specification.

[0015] The tray 12 can move horizontally (X direction) between the closed position (the position shown in Figures 1 and 2) and the open position via the tray moving mechanism 12M (shown schematically only in Figure 1). Although the tray moving mechanism 12M is not shown in detail, it may, for example, consist of a guide rail extending in the X direction and a moving body connected to the cover 13 and moving along the guide rail.

[0016] In the closed position of tray 12, the substrate holding part 14 is located within the internal space of the processing container 11, and the cover part 13 closes the opening of the side wall of the processing container 11. In the open position of tray 12, the substrate holding part 14 extends out of the processing container 11 (see Figure 6), and the substrate W can be transferred between the substrate holding part 14 and the substrate transport arm (not shown) via the aforementioned lifting pin. Furthermore, when tray 12 is in the open position, the cover part 13 opens the opening 11C of the side wall of the processing container 11. Therefore, the tray moving mechanism 12M can also be referred to as a cover opening and closing mechanism.

[0017] When the tray 12 is in the closed position, the internal space of the processing container 11 is divided by the plate 15 into an upper space 11A above the plate 15 where the substrate W is located during processing, and a lower space 11B below the plate 15. However, the upper space 11A and the lower space 11B are not completely separated.

[0018] That is, in the illustrated embodiment, the upper space 11A and the lower space 11B are connected through the aforementioned through hole 18 and through the elongated hole 19 (which is also a through hole) located near the connection between the plate 15 and the cover 13. The upper space 11A and the lower space 11B are also connected through the gap between the periphery of the plate 15 and the inner wall of the processing container 11. The aforementioned gap, through hole 18, and elongated hole 19 can also be referred to as the connecting path that connects the upper space 11A and the lower space 11B.

[0019] A substrate mounting stage (substrate holding part) that is fixed in a non-movable manner can be provided inside the processing container 11 to replace the movable tray 12. In this case, with the cover (not shown) of the processing container 11 open, the substrate transport arm (not shown) enters the container body and transfers the substrate W between the substrate mounting stage and the substrate transport arm.

[0020] The processing container 11 is provided with a first spray section 21 and a second spray section 22. The first spray section 21 and the second spray section 22 spray the processing fluid (in this example, carbon dioxide (hereinafter referred to as "CO 2")) supplied by the supercritical fluid (processing fluid in a supercritical state) supply source 30 into the internal space of the processing container 11.

[0021] Furthermore, it should be noted that the ordinal numbers ("first", "second", etc.) preceding the names of the constituent elements (e.g., "ejector") described in the description of the embodiments may not be consistent with the ordinal numbers preceding the names of the corresponding constituent elements described in the claims.

[0022] The first spray section 21 is located below the plate 15 of the tray 12 in the closed position. The first spray section 21 sprays CO2 (processing fluid) into the space 11B below, facing the bottom surface (upward) of the plate 15. The first spray section 21 may be formed by a through hole in the bottom wall of the processing container 11. The first spray section 21 may also be a nozzle installed on the bottom wall of the processing container 11.

[0023] The second ejection section 22 is located in front of the substrate W (in the positive X direction) on the substrate holding section 14 of the tray 12 in the closed position. The second ejection section 22 supplies CO2 into the upper space 11A. In the illustrated embodiment, the second ejection section 22 is located on the side wall of the processing container 11 opposite to the cover section 13.

[0024] The second ejection section 22 is composed of a rod-shaped nozzle. Specifically, the second ejection section 22 is formed by a plurality of ejection ports 22b extending from a tube 22a extending in the width direction (Y direction) of the substrate W. The plurality of ejection ports 22b are arranged at equal intervals in the Y direction, for example. Each ejection port 22b supplies CO2 into the upward space 11A towards the opening 11C (generally in the negative X direction).

[0025] The processing container 11 is further provided with a fluid discharge section 24 for discharging the processed fluid from the internal space of the processing container 11. The fluid discharge section 24 is configured as a manifold having a configuration substantially the same as that of the second spray section 22. Specifically, the fluid discharge section 24 is formed by a plurality of outlets 24b extending through a horizontally extending pipe 24a. The plurality of outlets 24b are arranged at equal intervals, for example, in the Y direction. Each outlet 24b faces upward and toward the elongated hole 19 of the plate 15.

[0026] In the illustrated embodiment, the fluid discharge section 24 is located near the opening 11C, in a recess that penetrates the bottom wall of the processing container 11. As shown by arrow F in Figure 1, CO2 flows through the area above the substrate W in the upper space 11A, then flows into the lower space 11B through a connecting path provided on the periphery of the plate body 15 (or through hole 19 formed in the plate body 15), and is then discharged from the fluid discharge section 24.

[0027] The arrangement of the second ejection section 22 and the fluid discharge section 24 is not limited to those shown in the figure. As long as the CO2 supplied from the second ejection section 22 to the processing container 11 passes over approximately the entire surface area above the substrate W in a slightly horizontal direction and is then discharged from the fluid discharge section 24, it can be arranged in any position. Specifically, for example, the second ejection section 22 and the fluid discharge section 24 can be arranged on both sides of the substrate W in the left-right direction (Y direction). Alternatively, a fluid discharge section with the same configuration (but with the discharge port facing downwards) can be provided on the top cover wall of the processing container 11 instead of the fluid discharge section 24 shown in FIG1.

[0028] The processing unit 10 is provided with a locking mechanism 25 for fixing the tray 12 in the closed position. The locking mechanism 25 has a guide hole 25A formed in the processing container 11, and a latch-like locking member 25C that moves up and down (Z direction) along the guide hole 25A through a lifting mechanism 25B (such as a pneumatic cylinder or ball screw). Figure 3 shows the locking member 25C in the lowered position (unlocked position). After the tray 12 is moved to the closed position and the locking member 25C is moved to the raised position (locked position) shown in Figure 1, even if the internal pressure of the processing container 11 increases, the tray 12 will not move in the open direction (negative X direction).

[0029] A gas recovery unit 28 is provided near the opening 11C of the processing container 11 (e.g., areas 29A or 29B in Figure 2). During the rinsing step described later, this unit attracts and recovers the CO2 gas that flows out of the opening 11C after being supplied to the processing container 11 in a gaseous state, or the CO2 gas about to flow out. The main reason for providing the gas recovery unit 28 is to comply with safety regulations regarding CO2 concentration.

[0030] The gas recovery unit 28 may be provided in a suitable component of the processing unit 10 near the opening 11C (e.g., locking member 25C, the wall of the processing container 11, the interior of the guide hole 25A, etc.). The gas recovery unit 28 may be configured as a manifold having a configuration substantially the same as that of the fluid discharge unit 24.

[0031] Figures 1 and 3 show the gas recovery unit 28 located in region 29A of Figure 2. The gas recovery unit 28 described here is constructed of a tube with the same structure as the fluid discharge unit 24 located in the recess formed in region 29A shown in Figure 2 (which has a plurality of suction ports arranged in the Y direction and opening upwards).

[0032] When the gas recovery unit 28 is located in region 29B as shown in Figure 2, it can be located on the wall of the processing container 11 facing the locking member 25C in the vertical direction, rather than on the locking member 25C. Although it can also be located on the top surface of the locking member 25C, if the gas recovery unit 28 is located on the movable locking member 25C, the piping connected to the gas recovery unit 28 will become complicated.

[0033] The gas recovery unit 28 may also be located on the wall of the processing container 11 on the opposite side (upper side) from the position shown in Figures 1 and 3 (for example, the position indicated by reference symbol 28' in Figure 3).

[0034] An air curtain spray section 26, which sprays shielding gas downwards, can be provided at a position facing the gas recovery section 28 vertically. The air curtain spray section 26 can also be configured as a manifold with a configuration substantially the same as the gas recovery section 28. Through the shielding gas sprayed from the air curtain spray section 26, an air curtain is formed in front of the opening 11C. By forming an air curtain, atmospheric air can be prevented from entering the processing container 11 from the opening 11C when the tray 12 is in the open position. The shielding gas system for forming the air curtain is the same gas as the processing fluid and the rinsing gas, namely CO2 gas. Alternatively, the gas recovery section 28 can be located on the upper side, and the air curtain spray section 26 on the lower side.

[0035] Next, the supply / discharge system for supplying and discharging CO2 to the processing container 11 in the supercritical drying apparatus will be described with reference to FIG4. Also, in FIG4, it should be noted that: for the sake of simplifying the diagram, the processing unit 10 is greatly simplified, and the processing unit 10 shown in FIG1 to FIG3 is reversed left and right, and the fluid discharge section 24 is shown in a position different from the actual situation, etc.

[0036] In the piping system diagram shown in Figure 4, the component indicated by the circled T is a temperature sensor, and the component indicated by the circled P is a pressure sensor. The component marked with the symbol OLF is an orifice (fixed diameter), which reduces the pressure of CO2 flowing in the piping downstream to the desired value. The component marked with the square SV is a safety valve (pressure relief valve), which prevents accidental excessive pressure from damaging components of the supercritical drying device such as piping or processing container 11. The component marked with the symbol FL is a filter, which removes particulate matter and other contaminants contained in CO2. The component marked with the symbol CV is a one-way valve (check valve). The component marked with the circled FM is a flow meter. The component marked with the square H is a heater used to regulate the temperature of CO2. When it is necessary to distinguish one of the above components from the others, a number is added to the end of the letter (e.g., "Filter FL2"). The component marked with the reference symbol VN (N is a natural number) is an on / off valve. Figure 1 shows 13 on / off valves V1 to V13.

[0037] The supercritical drying apparatus includes a supercritical fluid supply device (first fluid supply unit) 30, which serves as a supply source (30) for the supercritical processing fluid (supercritical CO2). The supercritical fluid supply device 30 has conventional components such as a carbon dioxide cylinder, a pressurizing pump, and a heater. The supercritical fluid supply device 30 has the capability to deliver CO2 at a pressure exceeding the supercritical state pressure (specifically, approximately 16 MPa), as described later.

[0038] The supercritical fluid supply device 30 is connected to the main supply line 32. The supercritical fluid supply device 30 supplies CO2 to the main supply line 32 in a supercritical state, but it may also become gaseous due to subsequent pressure or temperature changes. In this specification, the component referred to as "line" may be composed of piping (piping components).

[0039] The main supply line 32 branches into a first supply line 34 and a second supply line 36 at a branch point (first branch point) 33. The first supply line 34 is connected to the first spray section 21 of the processing container 11. The second supply line 36 is connected to the second spray section 22 of the processing container 11.

[0040] A discharge line 38 is connected to the fluid discharge section 24 of the processing container 11. An adjustable valve (regulating valve) 40 is provided on the discharge line 38. By adjusting the opening of the regulating valve 40, the primary pressure of the valve 40 can be adjusted, thereby regulating the pressure inside the processing container 11. The discharge rate of the processed fluid discharged from the processing container 11 can also be adjusted by adjusting the opening of the regulating valve 40.

[0041] Although not shown in Figure 4, the second supply line 36 branches into two near its connection to the second spray section 22 (downstream of the filter FL2). The ends of these two branches connect to opposite ends 23A and 23B of the pipe 22a of the second spray section 22 shown in Figure 2. This uniformizes the pressure distribution along the long side of the pipe 22a, resulting in a substantially uniform jet of the treated fluid from each spray port 22b. Similarly, the discharge line 38 also branches into two near its connection to the fluid discharge section 24 (upstream of the pressure relief valve SV). The ends of these two branches connect to opposite ends of the pipe 24a of the fluid discharge section 24. This allows the treated fluid to flow substantially uniformly into the pipe 24a from each discharge port 24b. Furthermore, the temperature sensor T and pressure sensor PS12 only need to be located at one of the two branches.

[0042] The control unit 100, schematically shown in Figure 4, provides feedback control over the opening degree of valve 40 (specifically, the position of the valve body) by maintaining the pressure within the processing container 11 at the set value based on the deviation between the measured pressure (PV) and the set value (SV) within the processing container 11. The measured pressure within the processing container 11, as shown in Figure 4, can be obtained from the pressure sensor indicated by the reference symbol PS located between the on / off valve V3 on the discharge line 38 and the processing container 11. That is, the pressure within the processing container 11 can be directly measured by the pressure sensor located within the processing container 11, or indirectly measured by the pressure sensor (PS12) located outside the processing container 11 (on the discharge line 38). Valve 40 can be set to a fixed opening degree based on a command value (non-feedback control) from the control unit 100.

[0043] The control unit 100 is, for example, a computer, and includes a calculation unit 101 and a storage unit 102. The storage unit 102 stores programs that control various processes executed in the supercritical drying apparatus (or a substrate processing system including a supercritical drying apparatus). The calculation unit 101 controls the operation of the supercritical drying apparatus by reading and executing the programs stored in the storage unit 102. The programs may be recorded on a computer-readable recording medium and installed from that recording medium into the storage unit 102 of the control unit 100. Examples of computer-readable recording media include hard disks (HD), floppy disks (FD), optical discs (CD), magneto-optical discs (MO), and memory cards.

[0044] At the branch point 42 located on the first supply line 34, a branch line 44 branches off from the first supply line 34. The branch line 44 is connected to the discharge line 38 at the connection point (merging point) 46 located on the discharge line 38. The connection point 46 is located upstream of the regulating valve 40.

[0045] Upstream of the regulating valve 40, the branch discharge line 50 branches off from the discharge line 38 at a branch point 48 located at the branch point 48, and then merges back into the discharge line 38. At a branch point 52 located at the branch point 58, two branch discharge lines 54 and 56 branch off from the discharge line 38. The downstream ends of the branch discharge lines 54 and 56 merge back into the discharge line 38. The downstream end of the discharge line 38 is connected, for example, to a fluid recovery device (not shown). Useful components (e.g., IPA (isopropanol)) contained in the CO2 recovered by the fluid recovery device are reused after appropriate separation. The downstream end of the branch discharge line 50 may also be open to the atmosphere without merging with the discharge line 38.

[0046] Upstream of the branch point (first branch point) 33, a discharge line 66 for discharging the treated fluid branches off from the branch point (second branch point) 64 of the main supply line 32.

[0047] Between the branch point 42 and the processing container 11, the flushing gas supply line 62 is connected to the junction point 60 of the first supply line 34. A flushing gas supply source (second fluid supply unit) 81 is connected to the flushing gas supply line 62. The flushing gas supply source 81 supplies flushing gas to the processing container 11 via the flushing gas supply line 62, the junction point 60, the first supply line 34, and the first ejector 21. The gas supplied from the flushing gas supply source 81 is the same substance as the processing fluid used in supercritical drying, differing only in phase. Specifically, the processing fluid used in supercritical drying is CO2 in a supercritical state (supercritical phase), while the flushing gas supplied from the flushing gas supply source 81 is CO2 in a gaseous state (gas phase).

[0048] Alternatively, the flushing gas supply source 81 and the flushing gas supply line 62 connected thereto (with a one-way valve CV and an on / off valve V11 located therebetween) can be connected to the junction point 74 of the second supply line 36 (see Figure 4(B)). In this case, the flushing gas flows into the processing container 11 from the second spray section 22.

[0049] A gas recovery pipeline 70 equipped with an on / off valve V12 is connected to the gas recovery unit 28. This gas recovery pipeline can be connected to the discharge pipeline 38 downstream of the on / off valve V5, for example. In Figure 4, the gas recovery pipeline 70 is shown cut off at (A) for ease of reading.

[0050] CO2 (CO2 gas) in a gaseous state (gas phase) is supplied to the air curtain spray section 26 from the air curtain supply source 71 (third fluid supply unit) via the air curtain supply line 72 equipped with an on / off valve V13. Alternatively, CO2 (CO2 gas) in a gaseous state (gas phase) can be supplied to the air curtain spray section 26 from the flushing gas supply source 81. In this case, for example, an air curtain supply line (not shown) with an on / off valve can be branched off from the flushing gas supply line 62 and connected to the air curtain spray section 26.

[0051] Next, an example of a supercritical drying method (substrate processing method) using the aforementioned supercritical drying apparatus will be briefly described. The following description is based on the processing formula and control program stored in the storage unit 102, which are automatically executed under the control of the control unit 100.

[0052] [Rinsing steps and substrate handling steps] Before the substrate W, such as a semiconductor wafer, is moved into the processing container 11, the tray 12 is moved to the open position. That is, the cover (lid body) 13 of the tray 12 opens the opening 11C of the processing container 11. Then, using a conventional method, the substrate W is placed on the substrate holding portion 14 of the tray 12, which is in the open position. For example, the substrate W can be placed on the substrate holding portion 14 by lowering the lifting pin (refer to the lifting pin 300 in the lower position shown in FIG6) after it is picked up by the substrate transport arm not shown in the figure.

[0053] Furthermore, the substrate W placed on tray 12 undergoes the following processes sequentially in a single-piece cleaning apparatus (not shown): (1) wet etching, chemical cleaning, etc.; (2) cleaning process to remove the chemical solution through a cleaning solution; and (3) IPA replacement process to replace the cleaning solution with IPA and form an IPA pool (liquid film). With an IPA pool formed on the surface of the substrate W, the substrate W is placed on tray 12.

[0054] During the period from when tray 12 moves to the open position until tray 12 holding substrate W returns to the closed position, a flushing step is performed to flush the internal space of the treatment container 11 with CO2 gas. The flushing step will be described in detail later.

[0055] After the rinsing step, the tray 12 holding the substrate W returns to the closed position, and the processing container 11 is sealed with the cover 13 before the supercritical process begins. The steps of the supercritical process are briefly explained below with reference to Figures 5A-5E. In Figures 5A-5E, the on / off valves fully coated with gray are in the closed state, and the partially coated valves are in the open state. For the sake of simplicity, gas lines and flow adjustment equipment (on / off valves, etc.) related to the rinsing step are omitted in Figures 5A-5E.

[0056] [Boosting Procedure] First, the pressurization process is implemented. The pressurization process is divided into an initial deceleration pressurization phase and a subsequent normal pressurization phase.

[0057] <Deceleration and Pressure Boost Phase> First, set all the on / off valves to the state shown in Figure 5A, and fix the opening of the regulating valve 40 to an appropriate fixed opening, for example, 2.5%. A portion (e.g., about 35%) of the CO2 supplied from the supercritical fluid supply device 30 to the main supply line 32 in a supercritical state is discharged from the pressure relief line 66 with an orifice OLF, and the remainder flows into the first supply line 34. A portion (e.g., about 35%) of the CO2 flowing into the first supply line 34 flows into the processing container 11 via the first spray section 21. Furthermore, the remaining CO2 flowing through the first supply line 34 does not flow into the processing container 11 but flows into the discharge lines 38 and 50 through the diversion line 44, and is blocked by the closed on / off valves V5 to V8.

[0058] After the initial deceleration and pressurization phase, the pressure of CO2 supplied from the supercritical fluid supply device 30 in a supercritical state gradually decreases, especially significantly when it flows into the larger processing container 11 under atmospheric pressure. That is, in the initial stage of introducing CO2 into the processing container 11, the pressure of CO2 inside the processing container 11 is lower than the critical pressure (e.g., approximately 8 MPa), so CO2 is in a gaseous state. The pressure difference between the first supply line 34 and the pressure inside the processing container 11 under atmospheric pressure is very large, so the gaseous CO2 flows into the processing container 11 at a high flow rate, raising concerns about disturbing the IPA pool on the surface of the substrate W and causing pattern collapse.

[0059] During the aforementioned deceleration and pressurization phase, a portion of the CO2 flowing in the main supply line 32 is diverted to the pressure relief line 66, and a portion of the CO2 flowing in the first supply line 34 is diverted to the branch line 44, thus reducing the velocity of CO2 flowing into the processing container 11. The orifice (OLF) of the first supply line 34 also contributes to reducing the flow rate of CO2 flowing into the processing container 11. Furthermore, the CO2 flowing into the processing container 11 from the first ejector 21 impacts the plate 15 of the tray 12, bypasses the plate 15, and enters the space 11A above the substrate W, thus reducing the flow rate of CO2 gas near the substrate W. Through these countermeasures, the possibility of pattern collapse is significantly reduced.

[0060] After the pressure inside the processing container 11 rises to a certain level, the flow rate of CO2 flowing into the processing container 11 decreases, making it less likely for pattern collapse to occur due to CO2 flowing at a high velocity around the substrate W. At this point, the process transitions to the normal pressurization stage. <Normal Pressure Boosting Phase>

[0061] That is, firstly, all the on / off valves are set to the state shown in Figure 5B, and the discharge of CO2 from the main supply line 32 through the pressure relief line 66 is stopped. This allows the pressure inside the processing container 11 to gradually increase at a rate higher than that of the deceleration and pressurization phase. At this time, the pressure in the downstream lines 44, 38, 50, 54, and 56, which are blocked by on / off valves V5 to V8, also gradually increases. This prevents the pressure inside the processing container 11 from dropping sharply immediately after the transition to the flow step.

[0062] When the pressure inside processing container 11 exceeds the critical pressure of CO2 (approximately 8 MPa), the CO2 present in processing container 11 (CO2 not mixed with IPA) becomes supercritical. After the CO2 inside processing container 11 becomes supercritical, the IPA on substrate W begins to dissolve into the supercritical CO2. The pressurization phase typically continues until the pressure inside processing container 11 reaches a level that ensures the mixture (CO2 + IPA) on substrate W remains in a supercritical state regardless of the IPA concentration and temperature of the mixture (supercritical state guarantee pressure). The supercritical state guarantee pressure is approximately 16 MPa.

[0063] <Circulation Steps> When the pressure sensor PS12 detects that the pressure inside the processing container 11 has reached the supercritical state guarantee pressure (16MPa), the opening and closing valves are set to the state shown in Figure 5C, and the operation mode of the regulating valve 40 is switched to feedback control mode. At this time, the control unit 100 (or its lower-level controller) performs feedback control based on the deviation between the pressure inside the processing container 11 (measured value PV) detected by the pressure sensor PS12 and the set value SV, so as to maintain the pressure inside the processing container 11 at the set value (set value SV = 16MPa).

[0064] In the flow step, supercritical CO2 supplied from the second ejector 22 to the processing container 11 flows over the area above the substrate and is then discharged from the fluid discharge section 24. At this time, a laminar flow of supercritical CO2 is formed inside the processing container 11, flowing slightly parallel to the surface of the substrate W. The IPA in the mixed fluid (IPA+CO2) on the surface of the substrate W exposed to the laminar flow of supercritical CO2 is gradually replaced by supercritical CO2. Finally, almost all of the IPA on the surface of the substrate W is replaced by supercritical CO2.

[0065] The mixed fluid, consisting of IPA discharged from fluid outlet 24 and supercritical CO2, is recovered after flowing through outlet line 38 (and branch outlet lines 54 and 56). The IPA contained in the mixed fluid can be separated and reused.

[0066] <Extraction Steps> After the replacement of IPA with supercritical CO2 is completed, all on / off valves are set to the state shown in Figure 5D, and the supply of CO2 to the processing container 11 is stopped. Furthermore, the set pressure of the processing container 11 is reduced to atmospheric pressure. This causes the opening of regulating valve 40 to increase significantly, gradually reducing the pressure inside the processing container 11 to atmospheric pressure. Simultaneously, the supercritical CO2 present within the pattern of the substrate W becomes gas and detaches from the pattern, and the gaseous CO2 is gradually discharged from the processing container 11. Finally, all on / off valves are set to the state shown in Figure 5E to discharge the CO2 remaining between on / off valves V1 and V4. This concludes the drying process of the substrate W.

[0067] <Substrate Removal Steps> The tray 12, on which the dried substrate W is placed, is moved to the open position, and the substrate W is removed from the processing unit 10 (from the housing of the processing unit 10) using a conventional method. At this time, for example, the aforementioned lifting pin can be used to lift the substrate W from the tray 12 in the open position, and then a substrate transport arm (not shown) can retrieve the substrate W from the lifting pin. Furthermore, the substrate transport arm can place the next substrate W on the lifting pin, and the substrate loading step for the next substrate W can continue. In this case, a rinsing step is also performed while the tray 12 is in the open position.

[0068] [Rinsing Procedure] Next, the rinsing step will be described in detail. The rinsing step is performed while the tray 12 is in the open position to move the substrate W into the processing container 11. After the opening 11C of the processing container 11 is opened, ambient gases (usually the atmosphere) around the processing container 11 enter the processing container 11, for example, through mutual diffusion. The atmosphere contains gases such as oxygen (O2), nitrogen (N2), water vapor (H2O), and ammonia, which are different from the processing fluid, i.e., carbon dioxide (CO2). (For ease of explanation, gases other than carbon dioxide are referred to as "impurity gases"). If supercritical drying is started in the presence of impurity gases in the processing container 11, there is a concern that foreign matter caused by the impurity gases may remain on the surface of the substrate after supercritical drying. Furthermore, since the critical temperature and critical pressure of water and ammonia are higher than those of carbon dioxide, there is also a concern that defects such as pattern collapse may occur. To solve this potential problem, in the rinsing step, CO2 gas is supplied into the processing container 11 as a rinsing gas while the processing container 11 is open, in order to reduce the concentration of impurity gases in the processing container 11.

[0069] <First Implementation of the Flushing Step> In the first embodiment, CO2 gas (flushing gas) is supplied to the treatment container 11 via the flushing gas supply source 81 through the flushing gas supply line 62, the manifold 60, the first supply line 34, and the first nozzle 21, following the path shown by the thick line in Figure 4. That is, the on-off valves V1, V2, V3, and V4 are set to the closed state, and the on-off valve V11 is set to the open state. The states of other on-off valves (on-off valves that are not directly related to the flow of fluid into and out of the treatment container) are arbitrary; for example, they can be set to a state that allows for smooth transition to the subsequent step, namely the pressurization step.

[0070] CO2 gas flowing into the processing container 11 from the first spray section 21 diffuses into the processing container 11 as indicated by arrow F2 in Figure 3, and flows out from the opening 11C of the processing container 11 as indicated by arrow F3. In this way, the concentration of CO2 gas in the processing container 11 increases while the concentration of impurity gases decreases.

[0071] At this time, valves V5, V6, V7, and V8 can be set to the closed state, and valve V12 can be set to the open state. The discharge line 38 is connected to a fluid recovery device (not shown) and becomes negative pressure, thus generating a suction force in the gas recovery section 28. Therefore, as shown by arrow F3, the CO2 gas flowing out from the opening 11C of the processing container 11 is attracted to the gas recovery section 28 and flows into the fluid recovery device through the gas recovery line 70 and the discharge line 38. Because the gas recovery section 28 generates a strong suction force, a negative pressure generating machine such as a suction pump or ejector can be installed in the flow path of the gas recovery line 70 or its downstream side.

[0072] At this time, the on / off valve V13 can be set to the open state, and CO2 gas (shielding gas) can be sprayed from the air curtain spray section 26. The CO2 gas sprayed from the air curtain spray section 26 flows towards the gas recovery section 28 as shown by arrow F4 in Figure 3, forming an air curtain between the air curtain spray section 26 and the gas recovery section 28. This prevents air located outside the air curtain from entering the inner side of the air curtain, thus improving flushing efficiency.

[0073] <Flushing Step 2 Implementation Example> In the second embodiment, CO2 gas (flushing gas) is supplied to the treatment container 11 from the flushing gas supply source via the manifold 74, the second supply line 36, and the second nozzle 22 (see Figure 4(B)). In this case, the on / off valves V1, V2, V3, and V4 can be set to the closed state, and the states of other on / off valves (on / off valves that are not directly related to the flow of fluid into and out of the treatment container) are arbitrary.

[0074] In this case, CO2 gas flows into the processing container 11 from the second ejector 22 and flows toward the opening 11C of the processing container 11, for example, as indicated by arrow F1 in Figure 3, and flows out from the opening 11C. Through the second embodiment, CO2 gas is ejected toward the opening 11C from the position furthest from the opening 11C (the position with the larger distance in the X direction from the opening 11C), thus improving the flushing efficiency.

[0075] In the second embodiment, the gas recovery unit 28 and the air curtain ejection unit 26 can also perform the same operations as in the first embodiment.

[0076] <Scene 3 of the rinsing procedure> In the third embodiment, the air curtain spray section 26 is also used as a spray section for flushing gas, and the first spray section 21 is used as a gas recovery section. By closing the on / off valves V1, V2, V3, V6, V7, and V8 and opening the on / off valves V4 and V5, the first spray section 21 can be connected to the discharge line 38 via a portion of the first supply line 34 and the branch line 44, thereby creating negative pressure on the first spray section 21. As shown by arrow F6 in FIG3, CO2 gas can be discharged from the processing container 11 via the first spray section 21, and the CO2 gas sprayed from the air curtain spray section 26 is simultaneously drawn into the processing container 11. This also allows for CO2 gas flushing of the processing container 11.

[0077] <Flushing Step 4 Implementation Mode> In the fourth embodiment, the processing fluid (CO2) supplied from the supercritical fluid supply device 30 is gasified and used as flushing gas. By closing the on / off valves V2, V3, and V4 and opening the on / off valves V9 and V1, gaseous CO2 can be ejected from the first ejector 21 into the processing container 11 as flushing gas, similar to the initial stage of the pressurization step. Except for the point where the processing fluid (CO2) supplied from the supercritical fluid supply device 30 is gasified and used as flushing gas, it is the same as the first embodiment.

[0078] Alternatively, flushing gas, which is formed by gasifying the processing fluid supplied by the supercritical fluid supply device 30, can be sprayed from the second spray section 22 into the processing container 11. However, in this case, the filter FL2, which does not have an orifice OLF on the upstream side, may be damaged due to the pressure difference. Therefore, it is preferable to install an appropriate pressure reducing means (such as an adjustable valve) on the upstream side of the filter FL2.

[0079] When the fluid discharge section 24 is located near the opening 11C of the processing container 11, in embodiments 1 to 4 of the rinsing step, the fluid discharge section 24 can be used as a gas recovery section. In this case, by opening the on / off valves V3 and V5 during the rinsing step and also appropriately fixing the opening of the regulating valve 40 at a larger opening, a suction force is generated in the fluid discharge section 24. Furthermore, in this case, the CO2 gas ejected from the air curtain ejection section 26 is drawn into the processing container 11, and the CO2 gas ejected from the first ejection section 21 (or the second ejection section 22) also flows toward the fluid discharge section 24, so the gas rinsing of the processing container 11 can be performed normally.

[0080] [Time point at which the rinsing process ends] In one embodiment, when the CO2 concentration inside the processing container 11 is detected to exceed a predetermined threshold (e.g., 80%), the control unit 100 ends the rinsing step and moves the tray 12 containing the substrate W to the closed position, thereby housing the substrate W inside the processing container 11 and closing the opening 11C of the processing container 11. Then, the control unit 100 performs a pressurization step.

[0081] CO2 concentration can be detected, for example, by a CO2 concentration meter (concentration sensor) located between the processing container 11 and the on / off valve V3 in the discharge line 38. In Figure 4, the circled S represents the CO2 concentration meter located inside the processing container 11.

[0082] In addition to the above-mentioned state, "supplying CO2 gas to the treatment container 11 for a predetermined time" can also be regarded as the CO2 concentration exceeding a predetermined threshold. The "predetermined time" can be determined through experiments using actual supercritical treatment devices.

[0083] The supply of CO2 gas (rinsing gas) to the processing container 11 is preferably continued until just before the tray 14 holding the substrate W moves to the closed position. Alternatively, CO2 gas can be continuously supplied to the processing container 11 at a flow rate that will not adversely affect the IPA pool on the substrate W while the tray 14 holding the substrate W moves to the closed position.

[0084] [First variant implementation of the processing unit] As shown in Figure 6, a means can also be provided to create a CO2 gas environment around the opening 11C of the processing container 11. In the configuration example shown in Figure 6, a gas ejector 102 is provided inside the housing 100 surrounding the processing unit 10 (e.g., the top cover of the housing 100). The gas ejector 102 is located above the tray 12 in the open position and can eject CO2 gas downward toward the tray 12. The downward flow of CO2 gas from the gas ejector 102 creates a CO2 gas environment around the tray 12 and around the opening 11C of the processing container 11. Therefore, in this case, it is not necessary to provide an air curtain ejector 26. This configuration is advantageous because it reduces the amount of impurity gas flowing into the processing container 11 from the time the supply of CO2 gas (rinsing gas) to the processing container 11 is stopped until the tray 12 carrying the substrate W is moved to the closed position.

[0085] A gas recovery unit 104 is provided below the tray 12 in the open position to recover the gas inside the outer casing 100. Therefore, high concentrations of CO2 gas can be prevented from leaking to the outside of the outer casing 100. If the gas recovery unit 104 is provided, the gas recovery unit 28 can be omitted. The main purpose of providing the gas recovery units (28, 104) is to comply with relevant safety regulations regarding hazardous gases; the method of CO2 gas recovery is arbitrary.

[0086] Clean air can also be ejected from the gas ejection section 102. When it is necessary to set the inside of the casing 100 to a harmless environment for humans during maintenance, clean air can be ejected from the gas ejection section 102 while the gas is recovered by the gas recovery section 104, thereby flushing the inside of the casing 100 with air.

[0087] If the configuration shown in Figure 6 is adopted, the area around the opening 11C of the treatment container 11 can be made into a CO2 gas environment, thus enabling efficient implementation of the rinsing steps according to embodiments 1 to 4, especially the rinsing step according to embodiment 3. In the rinsing step of embodiment 3, the CO2 gas rinsing inside the treatment container 11 can be performed by drawing ambient gas from the first spray section 21 and drawing CO2 gas around the opening 11C into the treatment container 11.

[0088] Furthermore, the component indicated by symbol 300 in Figure 6 is a lifting pin that can lift the substrate W on the tray 12. The lifting pin 300 can be raised and lowered through the through hole 18 of the tray 12. The substrate W, lifted upwards by the lifting pin, can be retrieved by a substrate transport arm (not shown) that enters the housing 100. When the substrate W is loaded, the substrate transport arm (not shown) places the substrate W on the lifting pin 300 in the raised position, and then lowers the lifting pin 300 below the tray 12 to place the substrate W on the tray 12. [Second variant implementation of the processing unit]

[0089] Figure 7 shows the second modified embodiment of the processing unit. In Figure 7, reference symbols indicating components that achieve the same function in the embodiments shown in Figures 1 to 4 are marked with 200.

[0090] The processing unit 200 shown in Figure 7 includes a cylindrical processing container 211 with an opening 211C at its upper end, and a movable cover 213 that closes the opening 211C of the processing container 211. A substrate holding portion 214 for holding the substrate W is provided on the cover 213. In Figure 7, the cover 213 in the closed position is indicated by a solid line, and the cover 213 in the open position is indicated by a chain line. When the cover 213 is in the open position, the substrate W can be transferred between the substrate holding portion 214 and a substrate transport arm (not shown). Supercritical drying is performed with the cover 213, in which the substrate W is held by the substrate holding portion 214, in the closed position.

[0091] A first spray section 221 and a fluid discharge section 224 are provided at the bottom of the processing container 211. A second spray section 222 is provided on the cover 213. Above the first spray section 221, a baffle plate 215 is provided to prevent the processing fluid sprayed from the first spray section 221 from directly spraying onto the substrate W. During supercritical drying, the first spray section 221 and the first spray section 21 of the aforementioned processing unit 10, the second spray section 222 and the first spray section 22 of the aforementioned processing unit 10, and the fluid discharge section 224 and the fluid discharge section 24 of the aforementioned processing unit 10 respectively achieve the same function.

[0092] The same CO2 flushing as that performed in the aforementioned processing unit 10 can also be performed in the processing unit 200 shown in Figure 7. To achieve this, a gas line 262 can be connected to the supply line 234 that supplies the processing fluid (supercritical CO2) to the first spray section 221. With the cover 213 in the open position, CO2 gas is supplied from the CO2 gas supply source 264 through the gas line 262 and the supply line 234 from the first spray section 221 into the processing container 211. This allows for gas flushing inside the processing container 211. At this time, a gas recovery section 228 is provided around the gap between the opening 211C of the processing container 211 and the cover 213 to recover the CO2 gas leaking out from the gap.

[0093] All embodiments of this invention are illustrative and not intended to be limiting. The above embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended patent applications.

[0094] The substrate is not limited to semiconductor wafers, but can also be other types of substrates used in the manufacture of semiconductor devices, such as glass substrates and ceramic substrates.

[0095] W: substrate 10: Processing Unit 11: Handling Containers 11A: Above Space 11B: Lower Space 11C: Opening 12: Pallet 12M: Cover Moving Mechanism 13: Cover 14:Substrate holding part 15:Plate body 16: Support pin 18: Through hole 19: Long hole 21: First jet section 22: Second jet section 22a: pipe 22b: Spray nozzle 23A, 23B: Ends 24: Fluid Discharge Section 24a: pipe 24b: Discharge outlet 25: Locking mechanism 25A: Guide hole 25B: Lifting mechanism 25C: Locking component 26: Air curtain spray section 28: Gas Recovery Department 28': Gas Recovery Section 29A, 29B: Areas 30: Supercritical fluid supply unit (First fluid supply section) 32: Main supply pipeline 33: Bifurcation point (first bifurcation point) 34: Supply Pipeline 1 36: Second Supply Pipeline 38: Discharge pipeline 40: Valve 42: Divergence point 44: Diversion Pipeline 46: Connection point 48: Divergence point 50: Branch discharge line 52: Divergence point 54, 56: Discharge lines 60: Convergence Point 62: Flushing gas supply line 64: Bifurcation point (second bifurcation point) 66: Discharge pipeline 70: Gas recovery pipeline 71: Air curtain supply source 72: Air curtain supply pipeline 74: Convergence Point 81: Fluid supply source for flushing gas (Second fluid supply unit) 100: Control Department 101: Calculation Department 102: Storage Department 104: Gas Recovery Department 200: Processing Unit 211: Handling Containers 211C: Open 213: Cover 214:Substrate holding part 215: Baffle 221: First jet section 222: Second jet section 224: Fluid Discharge Section 228: Gas Recovery Department 234: Supply pipeline 262: Gas pipeline 264: Supply Source 300: Lifting Pin F1~F6: Arrows V1~V13: On / off valves OLF: Orifice T: Temperature sensor SV: Safety valve (pressure relief valve) PS (PS12): Pressure sensor FL(FL1,FL2): Filter CV: Check valve

Claims

1. A substrate processing apparatus for drying a substrate with liquid adhering to its surface using supercritical drying technology, comprising: a processing container having an opening for moving the substrate in and out of the processing container; a cover that closes the opening of the processing container and is movable; a cover moving mechanism that moves the cover between a closed position that closes the opening and an open position that opens the opening; a substrate holding portion that horizontally holds the substrate in the processing container with the surface facing upwards; a fluid supply mechanism that supplies a supercritical processing fluid and a gaseous fluid composed of the same substance as the supercritical processing fluid to the processing container, and includes at least one supply line and a flow control device; and a control unit that controls the fluid supply mechanism as follows: In a first state, where the substrate is held in the processing container by the substrate holding part and the cover is in the closed position, the supercritical processing fluid is supplied to the processing container; and in a second state, where the substrate is not held in the processing container by the substrate holding part and the cover is in the open position, the gaseous fluid is supplied to the processing container. The fluid supply mechanism is connected to a first fluid supply unit capable of delivering the processing fluid in a supercritical state and a second fluid supply unit capable of delivering the gaseous fluid. The control unit controls the fluid supply mechanism as follows: in the first state, the processing fluid is supplied from the first fluid supply unit to the processing container; and in the second state, the gaseous fluid is supplied from the second fluid supply unit to the processing container. The processing container includes: a first ejection section disposed at the lower part of the processing container; and a second ejection section that ejects the processing fluid from a position away from the opening into the opening. The first fluid supply unit is connected to a first supply line and a second supply line; the first supply line is connected to the first spray unit; the second supply line is connected to the second spray unit; the second fluid supply unit is connected to the second supply line; the control unit controls the fluid supply mechanism to supply the gaseous fluid to the processing container via the second spray unit in the second state.

2. The substrate processing apparatus as described in claim 1, wherein, The control unit controls the fluid supply mechanism as follows: after supplying the gaseous fluid to the processing container in the second state, after moving the substrate into the processing container and closing the cover to enter the first state, the control unit supplies the processing fluid to the processing container.

3. The substrate processing apparatus of claim 1 further includes: a fluid recovery unit disposed near the opening, which attracts and recovers the gaseous fluid flowing out of the opening after being supplied to the processing container, or the gaseous fluid about to flow out.

4. The substrate processing apparatus as described in claim 3, wherein, The processing container is used to move the substrate horizontally out and in through the opening; the fluid recovery unit is located below the movement trajectory of the substrate when it is moved out and into the processing container, and the gaseous fluid flowing out from the opening flows downward into the fluid recovery unit.

5. The substrate processing apparatus as described in any one of claims 1 to 4 further includes: an air curtain ejection unit that ejects the processing fluid near the opening to form an air curtain that inhibits the inflow of external gas into the opening.

6. The substrate processing apparatus according to any one of claims 1 to 4 further comprises: a concentration sensor for measuring the concentration of the processing fluid in the processing container; and a control unit, in the second state, if the value of the concentration sensor becomes above a predetermined threshold when the gaseous fluid is supplied to the processing container, controlling the fluid supply mechanism to stop supplying the gaseous fluid to the processing container.

7. The substrate processing apparatus as described in any one of claims 1 to 4 further comprises: a concentration sensor for measuring the concentration of the processing fluid in the processing container; and a control unit, in the second state, if the value of the concentration sensor becomes above a predetermined threshold when the gaseous fluid is supplied to the processing container, controlling the cover moving mechanism to move the cover to the closed position and transfer to the first state.

8. The substrate processing apparatus as described in any one of claims 1 to 4, wherein, The cover and the substrate holding part are integrated into one unit. By moving the cover to the closed position, the substrate held by the substrate holding part is moved into the processing container.

9. The substrate processing apparatus as described in claim 8, wherein, When the substrate, which is held by the substrate holding part, is moved into the processing container, the direction is horizontal.

10. The substrate processing apparatus as described in claim 8, wherein, The processing container has the opening at its upper end; the direction in which the substrate held by the substrate holding part is moved into the processing container is up and down.

11. The substrate processing apparatus as claimed in claim 10 further includes: a fluid recovery unit disposed around the opening, which, when the cover is in the open position, recovers the gaseous fluid that flows out of the opening after being supplied to the processing container.

12. A substrate processing method, performed by a substrate processing apparatus, the substrate processing apparatus comprising: a processing container having an opening for moving a substrate in and out of the processing container; a cover that closes the opening of the processing container and is movable; a substrate holding portion that horizontally holds the substrate in the processing container with its surface facing upward; and a fluid supply mechanism that supplies a supercritical processing fluid and a gaseous fluid composed of the same substance as the supercritical processing fluid to the processing container, and includes at least one supply line and a flow control device; a first fluid supply portion having the capability to deliver the processing fluid in a supercritical state and a second fluid supply portion for delivering the gaseous fluid are connected to the fluid supply mechanism; the processing container having: a first ejection portion disposed at the lower part of the processing container; and a second ejection portion ejecting the processing fluid from a position away from the opening into the opening; and a first supply line and a second supply line connected to the first fluid supply portion; The first supply line is connected to the first spray section; the second supply line is connected to the second spray section; the second fluid supply section is connected to the second supply line; the substrate processing method includes the following steps: a supercritical drying process, which includes, while the substrate with liquid adhering to its surface is being moved into the processing container through the substrate holding section, supplying supercritical processing fluid to the processing container through the first fluid supply section and allowing it to circulate within the processing container, thereby replacing the liquid with the supercritical processing fluid; and a rinsing process, which, before the supercritical drying process, when the cover opens the opening to move the substrate into the processing container, supplies rinsing gas into the processing container through the second fluid supply section via the second spray section to create a rinsing gas environment inside the processing container.

13. The substrate processing method as described in claim 12, wherein, After stopping the supply of rinsing gas into the processing container, the substrate is moved into the processing container and the cover is closed, and then the supercritical drying process is performed.

14. The substrate processing method as described in claim 13, wherein, When the concentration of the rinsing gas in the processing container is detected by the concentration sensor to be above a predetermined threshold, the supply of rinsing gas to the processing container is stopped, and the substrate is moved into the processing container.

15. The substrate processing method as described in claim 12, wherein, The rinsing step includes a process of drawing in and recovering the rinsing gas that has been supplied to the processing container and is flowing out of the opening or is about to flow out.

16. The substrate processing method as described in claim 12, wherein, In this rinsing step, rinsing gas is supplied from a rinsing gas supply source to the supply line used to supply the supercritical processing fluid to the processing container, and the rinsing gas is supplied to the processing container through the supply line.

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