Substrate processing apparatus and substrate processing method

Abstract

A control unit of a substrate processing apparatus executes: a first step of supplying a processing fluid to a processing container during a first period from the start of supply of the processing fluid to the processing container until the pressure in the processing container is increased and the processing fluid in the processing container is in a supercritical state, and a second step of supplying the processing fluid to the processing container during a second period from the start of supply of the processing fluid to the processing container; supplying a processing fluid to the processing container via a first supply line and a first fluid release unit; a second step for supplying the processing fluid to the processing container via the second supply line and the second fluid release unit at a flow rate greater than the flow rate of the processing fluid supplied to the first fluid release unit in the first step during a second period after the processing fluid in the processing container becomes a supercritical state; and a density adjustment step in which, after the completion of the first step and before the start of the second step, the difference between the density of the processing fluid in a region upstream of the second on-off valve of the second supply line and the density of the processing fluid in the processing container is set to be less than a predetermined threshold value by means of a density adjustment mechanism.

Description

Technical Field

[0001] The invention relates to a substrate processing device and a substrate processing method. Background Art

[0002] In the manufacture of semiconductor devices having a stacked structure in which integrated circuits are formed on the surface of a substrate such as a semiconductor wafer, liquid treatment such as chemical cleaning or wet etching is performed. In recent years, in order to more reliably prevent the collapse of patterns caused by the continuous advancement of miniaturization, a drying method using a processing fluid in a supercritical state in a drying process as the final process of liquid treatment has been used (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication WO2023 / 013435 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a technique for reducing the particle level of a substrate after supercritical drying.

[0008] Technical solutions for solving technical problems

[0009] According to one embodiment of the present invention, a substrate processing device can be provided, which includes: a processing container capable of processing a substrate using a processing fluid in a supercritical state; a processing fluid supply unit for supplying the processing fluid to the processing container; and a control unit, the processing fluid supply unit including: a first fluid release unit for releasing the processing fluid into the processing container; a second fluid release unit for releasing the processing fluid into the processing container; a first supply pipeline for supplying the processing fluid to the first fluid release unit; a first opening and closing valve provided on the first supply pipeline; a second supply pipeline for supplying the processing fluid to the second fluid release unit; a second opening and closing valve provided on the second supply pipeline; and a density adjustment mechanism capable of adjusting the density of the processing fluid at a position upstream of the second opening and closing valve of the second supply pipeline, wherein the control unit is configured to control the substrate processing device to perform the following steps: the first step, at least from the start of supplying the processing fluid to the processing container to the time when the pressure in the processing container rises and the processing fluid in the processing container The first step comprises: a first step of supplying the treatment fluid to the first fluid release part via the first supply line by opening the first opening and closing valve and closing the second opening and closing valve during a first period from the time when the treatment fluid in the treatment container becomes supercritical, and supplying the treatment fluid to the second fluid release part via the second supply line at a flow rate greater than the flow rate of the treatment fluid supplied from the first supply line to the first fluid release part during the first period; and a density adjustment step of making the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold value by the density adjustment mechanism after the first supply period ends and before the second supply period begins, wherein the density in the pipeline is defined as the density of the treatment fluid in the area upstream of the second opening and closing valve of the second supply line, and the density in the container is defined as the density of the treatment fluid in the treatment container. In this specification, a "pipeline" may also be referred to as a "line".

[0010] Effects of the Invention

[0011] According to the above-mentioned one embodiment of the present invention, the particle level of the substrate after supercritical drying can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a cross-sectional view showing a schematic structure of a substrate processing system according to an embodiment.

[0013] Figure 2 It means assembly in Figure 1A schematic cross-sectional view of an example of the structure of a liquid processing unit in a substrate processing system.

[0014] Figure 3 It means assembly in Figure 1 A schematic longitudinal cross-sectional view of an example of the structure of a supercritical drying unit in a substrate processing system.

[0015] Figure 4 yes Figure 3 Schematic cross-sectional view of the supercritical drying unit along IV-IV in .

[0016] Figure 5 It means Figure 3 and Figure 4 FIG. 1 is a piping system diagram showing an example of a supply / exhaust system connected to a processing container of a supercritical drying unit shown in FIG.

[0017] Figure 6A-6E This is a diagram showing an example of the state of the supply / discharge system in each step of the supercritical drying process.

[0018] Figure 7 This is a graph showing an example of the density adjustment process (pressure relief process) and pressure changes before and after it.

[0019] Figure 8 It is a piping system diagram of a modified implementation.

[0020] Fig. 9 This is a piping system diagram of another modified embodiment.

[0021] Fig.10 This is a schematic longitudinal sectional view showing a modified embodiment of the supercritical drying unit.

[0022] Description of Reference Numerals

[0023] W substrate (wafer)

[0024] 311 Processing Container

[0025] 4 Control Unit

[0026] 321 1st fluid release part

[0027] 322 second fluid release unit

[0028] 234 1st supply line

[0029] 236 2nd supply line

[0030] AV203 No.1 on-off valve

[0031] AV204, AV205 second on-off valve

[0032] 266 Exhaust line

[0033] AV202 On / Off Valve

[0034] H (heater) density adjustment mechanism. DETAILED DESCRIPTION

[0035] Hereinafter, with reference to the accompanying drawings, embodiments of the substrate processing method and substrate processing device described in the present application will be described in detail. In addition, the present invention is not limited to the embodiments shown below. In addition, it should be noted that the accompanying drawings are schematic, and the relationship between the dimensions of the elements, the ratio of the elements, etc. are sometimes different from reality. Furthermore, the drawings sometimes include parts with different dimensional relationships and ratios.

[0036] <Overview of substrate processing system>

[0037] First, refer to Figure 1 A schematic configuration of a substrate processing system 1 according to the embodiment will be described. Figure 1 1 is a diagram showing a schematic configuration of a substrate processing system 1 according to an embodiment. In order to clarify the positional relationship, the X-axis, Y-axis, and Z-axis are defined to be orthogonal to each other, and the positive direction of the Z-axis is defined as the vertical upward direction.

[0038] like Figure 1 As shown, the substrate processing system 1 includes a feeding station 2 and a processing station 3. The substrate processing system 1 is an example of a substrate processing device. The feeding station 2 and the processing station 3 are arranged adjacent to each other.

[0039] The loading and unloading station 2 includes a carrier placement unit 11 and a conveying unit 12. A plurality of carriers C storing a plurality of semiconductor wafers W (hereinafter referred to as "wafers W") in a horizontal state are placed on the carrier placement unit 11. Wafers W are an example of substrates.

[0040] The conveying unit 12 is provided adjacent to the carrier placement unit 11, and includes a substrate conveying device 13 and an interface 14 therein. The substrate conveying device 13 includes a wafer holding mechanism for holding a wafer W. The substrate conveying device 13 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and conveys the wafer W between the carrier C and the interface 14 using the wafer holding mechanism.

[0041] The processing station 3 is disposed adjacent to the conveying section 12. The processing station 3 includes a conveying section 15, a plurality of liquid processing units 16, and a plurality of supercritical drying units 17. The plurality of liquid processing units 16 and the plurality of supercritical drying units 17 are arranged on both sides of the conveying section 15. The arrangement and number of the liquid processing units 16 and the supercritical drying units 17 are not limited to Figure 1 Configuration and quantity shown.

[0042] The conveying section 15 is provided with a substrate conveying device 18 inside. The substrate conveying device 18 includes a wafer holding mechanism for holding the wafer W. In addition, the substrate conveying device 18 can move in the horizontal direction and the vertical direction and rotate around the vertical axis, and uses the wafer holding mechanism to convey the wafer W between the interface 14, the liquid processing unit 16, and the supercritical drying unit 17.

[0043] The liquid processing unit 16 performs a series of liquid processing (wet etching processing and cleaning processing using chemical liquid, rinsing processing, etc.) on the wafer W, and then performs a protective liquid film forming process for forming a protective liquid film such as IPA as a final process. The configuration example of the liquid processing unit 16 will be described later.

[0044] The supercritical drying unit 17 performs supercritical drying treatment on the wafer W having the protective liquid film formed on the surface (ie, the front surface) by the liquid processing unit 16. An example of the configuration of the supercritical drying unit 17 will be described later.

[0045] In addition, the substrate processing system 1 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.

[0046] The control unit 19 includes a microcomputer and various circuits including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, etc. The CPU of the microcomputer realizes the control described below by reading and executing a program stored in the ROM.

[0047] In addition, the program may be recorded in a computer-readable recording medium and installed from the recording medium into the storage unit 20 of the control device 4. Examples of the computer-readable recording medium include a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), and a memory card.

[0048] The storage unit 20 can be 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.

[0049] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the transfer station 2 takes out a wafer W from the carrier C placed on the carrier placement portion 11, and places the taken-out wafer W on the delivery portion 14. The wafer W placed on the delivery portion 14 is taken out from the delivery portion 14 by the substrate transfer device 18 of the processing station 3, and is transferred to the liquid processing unit 16.

[0050] The wafer W sent to the liquid treatment unit 16 is sent out from the liquid treatment unit 16 by the substrate conveying device 18 after a predetermined liquid treatment is performed by the liquid treatment unit 16, with a protective liquid film such as IPA formed on the surface. The wafer W sent out from the liquid treatment unit 16 is sent to the supercritical drying unit 17 by the substrate conveying device 18, and the supercritical drying unit 17 performs supercritical drying treatment.

[0051] The wafer W processed by the supercritical drying unit 17 is transferred from the supercritical drying unit 17 by the substrate transfer device 18 and placed on the delivery unit 14. The processed wafer W placed on the delivery unit 14 is returned to the carrier C of the carrier placement unit 11 by the substrate transfer device 13.

[0052] <Structure of liquid processing unit>

[0053] Next, refer to Figure 2 The structure of the liquid processing unit 16 will be described. The liquid processing unit 16 is configured as a single-chip liquid processing unit. The liquid processing unit 16 itself can use a liquid processing unit having a known structure, and an example thereof will be briefly described below.

[0054] like Figure 2 As shown, liquid processing unit 16 includes wafer holding mechanism 24 disposed in outer chamber 23 forming a processing space. Wafer holding mechanism 24 is configured to hold wafer W in a horizontal posture and to rotate wafer W around a vertical axis.

[0055] In the liquid processing unit 16, the processing liquid (chemical solution, rinse liquid, IPA, etc.) required for liquid processing is sequentially supplied from the nozzle 26a located above the wafer W which is carried and rotated by the nozzle arm 26, thereby performing liquid processing on the surface (device formation surface) of the wafer W. Figure 2 Only one nozzle arm 26 and one nozzle 26a are shown in the figure, but they can be provided in desired numbers.

[0056] In the final step of the liquid treatment, IPA (protective liquid) is supplied from the nozzle 26a for supplying IPA to the surface of the wafer W, and the liquid (usually DIW as a rinse liquid) covering the surface of the wafer W is replaced with IPA. After that, the thickness of the IPA liquid film covering the surface of the wafer W is adjusted by adjusting the supply flow rate of IPA from the nozzle and the rotation speed of the wafer W, and then the release of IPA from the nozzle and the rotation of the wafer W are stopped. As a result, the surface of the wafer W is covered with a protective liquid film of a desired film thickness.

[0057] As a treatment liquid (protection liquid) for forming a protective liquid film, IPA (isopropyl alcohol) is currently used in most cases. As a protection liquid, a mixture of a low-alcohol (such as ethanol, methanol, etc.) other than IPA and a liquid having a polarity different from that of the low-alcohol can also be used. The protection liquid is a liquid that has a high affinity with CO2 (carbon dioxide) used as a treatment fluid in the supercritical drying process.

[0058] <Structure of supercritical drying unit>

[0059] Next, refer to Figure 3 to Figure 5 The structure of the supercritical drying unit 17 will be described. The supercritical drying unit 17 is used to perform a supercritical drying process in which a substrate having a protective liquid film (IPA in this case) formed on the surface is dried using a process fluid in a supercritical state.

[0060] like Figure 3 and Figure 4 As shown, the supercritical drying unit 17 includes a processing container 311 and a substrate holding tray 312 (hereinafter, simply referred to as “tray 312 ”) that holds the wafer W in the processing container 311 .

[0061] The tray 312 includes a cover 313 that closes an opening 311C provided in the side wall of the processing container 311, and a substrate holding portion 314 that is integrally connected to the cover 313 and extends in the horizontal direction. The substrate holding portion 314 includes a plate 315 and a plurality of support pins 316 provided on the upper surface of the plate 315. The wafer W is placed on the support pins 316 in a horizontal posture with its surface (the surface on which the device or pattern is formed) facing upward. When the wafer W is placed on the support pins 116, a gap 17 is formed between the upper surface of the plate 15 and the lower surface (back surface) of the wafer W.

[0062] The plate 315 has a plurality of through holes 318 extending vertically through the plate 315. The plurality of through holes 318 serve to connect the space above the plate 315 with the space below the plate 315 and to allow the substrate conveying device 18 (see Figure 1 ) and the plate 315 through which the lifting pins (not shown) pass for transferring the chip W.

[0063] The tray 312 can pass Figure 3 The tray moving mechanism 312M schematically shown in FIG. 1 moves in the horizontal direction (Y direction) between the closed position and the open position. In the closed position of the tray 312, the substrate holding portion 314 is located in the internal space of the processing container 311, and the cover portion 313 closes the opening of the side wall of the processing container 311. In the open position of the tray 312, the substrate holding portion 314 is outside the processing container 311 (see FIG. 11 ). Figure 1) can transfer the chip W between the substrate holding portion 314 and the substrate transfer arm (not shown) via lift pins (not shown).

[0064] When the tray 312 is in the closed position (refer to Figure 3 and Figure 4 ), the internal space of the processing container 311 is divided into an upper space 311A ​​above the plate 315 (where the wafer W is arranged) and a lower space 311B below the plate 315 by the plate 315. However, the upper space 311A ​​and the lower space 311B are not completely separated. The upper space 311A ​​and the lower space 311B are fluidically connected via the through hole 318 and the gap between the peripheral edge of the plate 315 and the inner wall surface of the processing container 111.

[0065] The processing container 311 is provided with a first fluid release part 321 and a second fluid release part 322. The first fluid release part 321 and the second fluid release part 322 release the processing fluid (in this example, carbon dioxide (hereinafter, for simplicity, also referred to as "CO2")) supplied from a supply source 230 of a supercritical fluid (processing fluid in a supercritical state) into the internal space of the processing container 311.

[0066] The first fluid release part 321 is disposed below the plate 315 of the tray 312 in the closed position. The first fluid release part 321 faces the lower surface of the plate 315 (upward) and releases CO2 (process fluid) into the lower space 311B. The first fluid release part 321 can be composed of a through hole formed in the bottom wall of the processing container 311. The first fluid release part 321 can also be a nozzle body mounted on the bottom wall of the processing container 311.

[0067] The second fluid release part 322 is provided so as to be located to the side (position advanced in the positive direction Y) of the wafer W placed on the substrate holding part 314 of the tray 312 in the closed position. The second fluid release part 322 supplies CO2 into the upper space 311A. In the illustrated embodiment, the second fluid release part 322 is provided on the side wall of the processing container 311 on the opposite side of the cover part 313.

[0068] In the illustrated embodiment, the second fluid release portion 322 is formed as a so-called "strip nozzle". Specifically, the second fluid release portion 322 is formed by penetrating a plurality of release ports 322b in a tube 322a extending in the width direction (X direction) of the wafer W. The plurality of release ports 322b are arranged at equal intervals in the X direction, for example. Each release port 322b releases CO2 into the upper space 311A ​​in a horizontal direction or a slightly oblique downward direction toward the opening 313.

[0069] The structure of the second fluid release part 322 is not limited to the above structure. The second fluid release part 322 can be formed near the surface of the wafer W in one direction ( Figure 4 If the supercritical CO2 can be released in a laminar flow of supercritical CO2 flowing in the Y direction (in the Y direction) of the wafer, and the supercritical CO2 can be released in a manner that is substantially the same at the flow rate of the supercritical CO2 in the entire region of the wafer, then its structure is arbitrary. Therefore, as the structure of the second fluid release portion 322, in most cases, a structure similar to the structure shown in the figure can be adopted. The second fluid release portion 322 can also be formed by providing a hole extending in the X direction inside an elongated block extending in the X direction, and providing a plurality of release ports extending in a substantially Y direction and connected to the hole in the block. Regardless of the structure adopted, there is also some space (in the example shown, the internal space of the tube 322a) immediately upstream of the release port of the second fluid release portion 322. In the present invention, the technology for suppressing particles will be described in detail later, wherein the particles come from pollutants that enter the (internal) space or accumulate in the (internal) space.

[0070] The processing container 311 is also provided with a fluid discharge portion 324 for discharging the processing fluid from the internal space of the processing container 311. The fluid discharge portion 324 may also have a structure substantially the same as the second fluid release portion 322. The fluid discharge portion 324 can be formed by providing a plurality of discharge ports 324b on a tube 324a extending in a horizontal direction, similarly to the second fluid release portion 322. The plurality of discharge ports 324b are arranged at equal intervals in the X direction, for example. Each discharge port 324b faces upward and toward the long hole 319 of the plate 315.

[0071] In the illustrated embodiment, the fluid discharge portion 324 is disposed in a recess formed in the bottom wall of the processing container 311 near the opening 311C. Figure 3 As shown by the middle arrow F, after CO2 flows through the area above the chip W in the upper space 311A, it flows into the lower space 311B through the connecting path provided in the peripheral portion of the plate 315 (or the through hole 319 formed in the plate 315), and is then discharged from the fluid discharge portion 324.

[0072] The configuration of the second fluid release part 322 and the fluid discharge part 324 is not limited to the configuration shown in the figure, and can be configured at any position as long as the CO2 supplied from the second fluid release part 322 to the processing container 311 passes through the area above the substantially entire surface of the chip W in a substantially horizontal direction and is then discharged from the fluid discharge part 324.

[0073] The supercritical processing unit 17 is provided with a locking mechanism 325 for maintaining the tray 312 in the closed position even when the interior of the processing container 311 becomes high pressure. The locking mechanism 325 has a latch-shaped locking member 325C, which is raised and lowered in a guide hole 325A formed in the processing container 311 by a lifting mechanism 325B.

[0074] Next, refer to Figure 5 A supply / exhaust system for supplying and exhausting carbon dioxide (hereinafter, also referred to as “CO 2 ” for simplicity) to and from the processing container 311 of the supercritical drying unit 17 will be described.

[0075] exist Figure 5 In the piping system diagram shown, the component T surrounded by a square is a temperature sensor. In order to distinguish each other, the temperature sensor is given a reference numeral in the form of "T+3 digits". The component P surrounded by a circle is a pressure sensor. In order to distinguish each other, each pressure sensor is marked with a reference numeral in the form of "P+3 digits". The component with the reference numeral OLF is a throttle hole (fixed throttling part) that reduces the pressure of CO2 flowing through it. The component with the reference numeral F is a filter for removing pollutants such as particulates contained in CO2. The component with the reference numeral CV is a one-way valve (check valve). The component with the reference numeral FM is a flow meter. The component H surrounded by a quadrilateral is a heater for regulating the temperature of CO2. The component with the reference numeral in the form of "AV+3 digits" is an on-off valve.

[0076] The supercritical processing device has a supercritical fluid supply device 230. In the present embodiment, the supercritical fluid is CO2 in a supercritical state (hereinafter, also referred to as "supercritical CO2"). The supercritical fluid supply device 230 has a known structure including, for example, a carbon dioxide gas cylinder, a pressure pump, a heater, etc. The supercritical fluid supply device 230 has the ability to deliver supercritical CO2 at a pressure that can reliably increase the pressure in the processing container 311 to a supercritical state guarantee pressure (specifically, for example, about 16 MPa) described later, for example, about 20 MPa.

[0077] The supercritical fluid supply device 230 is connected to a main supply line 232. CO2 flows out from the supercritical fluid supply device 230 to the main supply line 232 in a supercritical state, but may also become a gas state due to subsequent expansion (pressure reduction) or temperature change. In this specification, the component referred to as a "pipeline" can be composed of a pipe (piping component).

[0078] The main supply line 232 branches (forks) at a branch point 233 into a first supply line 234 and a second supply line 236. The first supply line 234 is connected to the first fluid discharge portion 321 of the processing container 311.

[0079] The second supply line 236 is connected to the second fluid release portion 322 of the processing container 311. Figure 3 and Figure 4 As shown in the figure, when the second fluid release part 322 is formed by a tube 322a extending in the horizontal direction and having a plurality of holes 322b, the second supply line 236 branches on the downstream side of the branch point 233 to form two second branch supply lines 236A and 236B. The downstream ends of the second branch supply lines 236A and 236B are connected to both ends of the tube 322a (at Figure 4 The two components are connected as shown in the figure by reference numerals 323A and 323B).

[0080] The discharge line 238 is connected to the fluid discharge part 324 of the processing container 311. When the fluid discharge part 324 is formed of a tube extending in the horizontal direction and having a plurality of holes therethrough, as in the second fluid discharge part 322, the second fluid discharge part 322 is composed of branch discharge lines 238A and 238B connected to both ends of the tube. These branch discharge lines 238A and 238B merge to form a single discharge line 238.

[0081] The discharge line 238 is provided with a pressure regulating valve 240. By adjusting the opening of the pressure regulating valve 240, the primary side pressure of the pressure regulating valve 240 can be adjusted, and thus the pressure in the processing container 311 can be adjusted. As the pressure regulating valve 240, a valve designed as a back pressure valve (BPV) can be used.

[0082] Depend on Figure 1 The control device 4 (or its lower controller) shown schematically performs feedback control on the opening of the pressure regulating valve 240 based on the deviation between the measured value (PV) and the set value (SV) of the pressure in the processing container 311, so as to maintain the pressure in the processing container 311 at the set value. The pressure substantially the same as the pressure in the processing container 311 can be detected by the pressure sensor PS203 provided between the on-off valve AV207 and the processing container 311, wherein the on-off valve AV207 is provided in the discharge line 238 (branch discharge line 238A). Therefore, in the above-mentioned feedback control, the detection value of the pressure sensor PS203 can also be used as the above-mentioned measured value (PV). The pressure in the processing container 311 can also be directly measured by the pressure sensor provided in the processing container 311.

[0083] The bypass line 244 branches from the first supply line 234 at a branch point 242 set on the first supply line 234. The bypass line 244 is connected to the discharge line 238 at a confluence point 246 set on the discharge line 238. The confluence point 246 is located on the upstream side of the pressure regulating valve 240.

[0084] A branch discharge line 250 branches from the discharge line 238 at a branch point 248 set on the discharge line 238 upstream of the pressure regulating valve 240. The downstream end of the branch discharge line 250 is open to the air space outside the supercritical processing device or connected to a plant exhaust pipe.

[0085] At a branch point 252 set in the discharge line 238, two branch discharge lines 254 and 256 are branched from the discharge line 238. The downstream ends of the branch discharge lines 254 and 256 merge with the discharge line 238 again. The downstream end of the discharge line 238 is connected to, for example, a fluid recovery device (not shown). The useful components (for example, IPA (isopropyl alcohol)) contained in the CO2 recovered by the fluid recovery device are appropriately separated and reused.

[0086] A purge gas supply line 262 is connected to a junction 260 set in the first supply line 234 between the branch point 242 and the processing container 311. A purge gas (for example, nitrogen gas) can be supplied to the processing container 311 through the purge gas supply line 262.

[0087] The exhaust line 266 branches from a branch point 264 set to the main supply line 232 immediately on the upstream side of the branch point 233 .

[0088] Next, refer to Figure 6A to Figure 6E An embodiment of a drying method (substrate processing method) performed using the above-mentioned supercritical processing apparatus is described. The drying method described below is automatically performed under the control of the control device 4 based on the processing plan and control program stored in the storage unit 19 of the control device 4.

[0089] exist Figure 6A to Figure 6E In the figure, the on-off valves painted black indicate a closed state, the on-off valves not painted black (hollow) indicate an open state, and the pipeline containing high-pressure CO 2 is indicated by a thick solid line.

[0090] [Feeding process]

[0091] use Figure 1The substrate transfer device 18 shown in the figure places the wafer W having been subjected to liquid treatment by the liquid treatment unit 16 and having a protective liquid film of IPA formed on the surface on the plate 315 of the tray 314 waiting at the substrate transfer position. When the tray 314 carrying the wafer W moves to the processing position, a closed processing space is formed in the processing container 311, and the wafer W is located in the processing space.

[0092] [Pressure Boosting Step (1st Step)]

[0093] Next, a pressure increasing step is performed, which includes an initial deceleration pressure increasing stage and a normal pressure increasing stage following the deceleration pressure increasing stage.

[0094] In addition, the on-off valve AV213 can also be set to always be closed in the pressure-increasing / circulation process, and to be opened in the pressure-reducing process. From the start time of the pressure-increasing process to the end time of the pressure-reducing process, the on-off valve AV213 can always be in a closed state, or it can be set to an open state at an appropriate time as needed. When the on-off valve AV213 is in an open state, exhaust can be performed without passing through the pressure regulating valve 240, thereby shortening the exhaust or pressure-reducing time. In addition, the on-off valve AV206 is also opened only when the processing container 311 is purged. In the following description, in the processing of the wafer W, the description is made on the premise that the on-off valve AV206 and the on-off valve V213 are always in a closed state.

[0095] <Deceleration and pressure increase stage>

[0096] First, if Fig. 6A As shown, the on-off valves AV204, AV205, AV211, and AV212 are closed, and the on-off valves AV201, AV202, AV203, AV209, and AV210 are opened. In this deceleration and pressure increase stage, the pressure regulating valve 240 may also be fixed to an appropriate opening, for example, the same opening as the initial opening in the circulation process described later. A portion of the CO2 sent from the supercritical fluid supply device 230 to the main supply line 232 in a supercritical state is discharged from the exhaust line 266, and the remaining portion of the CO2 flows into the first supply line 234, and a portion of it flows into the processing container 311 via the first fluid release portion 321. In addition, a portion of the CO2 flowing in the first supply line 234 does not go to the processing container 311 but flows into the exhaust line 238 through the bypass line 244, and after flowing through the exhaust line 238, it is discarded in the factory exhaust pipe or recovered for reuse.

[0097] At the beginning of the deceleration and pressure increase phase, the pressure of CO2 delivered in a supercritical state from the supercritical fluid supply device 230 is greatly reduced when it flows into the larger processing container 311 at normal pressure. That is, at the beginning of the introduction of CO2 into the processing container 311, the pressure of CO2 in the processing container 311 is lower than the critical pressure (about 8MPa), so CO2 becomes a gas state. Since the difference between the pressure in the first supply line 234 and the pressure in the processing container 311 at normal pressure is very large, CO2 flows into the processing container 311 at a high flow rate at the beginning of the deceleration and pressure increase phase. When CO2 (especially high-speed and gaseous CO2) collides with the wafer W or flows near the wafer W, the paddle of the IPA at the peripheral portion of the wafer W collapses (partially evaporates or shakes), and pattern collapse may occur.

[0098] In this embodiment, in the deceleration and pressure increase stage, that is, at the beginning of the introduction of CO2 into the processing container 311, a part of CO2 flowing through the main supply line 232 is released to the exhaust line 266 (release operation A), and a part of CO2 flowing through the first supply line 234 is released to the bypass line 244 (release operation B). In this way, CO2 is prevented from flowing into the processing container 311 at a high flow rate.

[0099] Furthermore, in this embodiment, since the orifice (OLF) is provided in the first supply line 234, the flow rate of CO2 flowing from the first fluid release portion 321 into the processing container 311 is lower than that in the case without the orifice. Therefore, the pattern collapse based on the above mechanism can be suppressed.

[0100] The pattern collapse based on the above mechanism can only occur at the beginning of the introduction of CO2 into the processing container 112. This is because as the internal pressure of the processing container 112 increases, the flow rate of CO2 flowing into the processing container 112 through the first fluid release part 121 gradually decreases. Therefore, the deceleration and pressure increase stage can be performed in a short time, such as about 10 to 20 seconds. In addition, it is not necessary to perform the release operations A and B during the entire period of the deceleration and pressure increase stage, and the release operation A can also be stopped first. In addition, the on-off valve AV210 of the exhaust pipeline 238 can also be closed in the middle of the deceleration and pressure increase stage.

[0101] <Normal voltage boost stage>

[0102] Then, if Figure 6BAs shown, the on-off valves AV202 and AV210 are also closed. This switching can be performed, for example, when the pressure in the processing container 311 (for example, the detection value of the pressure sensor PS203) exceeds a predetermined threshold value. Alternatively, the switching can be performed when a predetermined time (for example, about 10 seconds mentioned above) has passed since the start of the deceleration and pressure increase phase. In this normal pressure increase phase, in order to smoothly transfer to the circulation process described later, it is preferred to fix the opening of the pressure regulating valve 240 in advance to the initial opening in the circulation process described later.

[0103] With the switching of the above-mentioned on-off valves, CO2 flowing from the bypass line 244 into the exhaust line 238 and discharged through the exhaust line 238 is blocked by the on-off valves AV210 to AV212. In addition, the pipeline 250 is also closed by the on-off valve V213 in the closed state. Therefore, CO2 is filled into the pipelines 244, 238, 250, 254, and 256, and the pressure in the pipelines gradually increases. As a result, the flow rate of CO2 flowing out from the first supply line 234 to the bypass line 244 is also reduced, and the pressure in the processing container 112 increases at a higher pressure increase rate than the deceleration pressure increase stage.

[0104] When the pressure in the processing container 311 exceeds the critical pressure of CO2 (about 8 MPa), the CO2 (CO2 not mixed with IPA) in the processing container 311 becomes supercritical. When the CO2 in the processing container 312 becomes supercritical, the IPA on the wafer W begins to dissolve in the supercritical CO2.

[0105] After the pressure in the processing container 112 exceeds the critical pressure of CO2, the above-mentioned normal pressure increase stage is continued until the predetermined pressure increase target pressure is reached. In this embodiment, the pressure increase target pressure is set to a pressure that can ensure that the CO2 in the processing container 112 is maintained in a supercritical state (hereinafter, for the sake of simplicity, it is also referred to as "supercritical state guarantee pressure"), that is, 16 MPa, regardless of the IPA concentration and temperature in the mixed fluid (CO2+IPA) on the wafer W.

[0106] [Pressure relief process (density adjustment process)]

[0107] Through the pressure sensor (such as Figure 5 After the pressure sensor PS203 confirms that the pressure in the processing container 12 has reached the supercritical state guarantee pressure, Figure 6CAs shown, while all the on-off valves except the on-off valve AV202 are closed, the on-off valve AV202 is opened for a short time (e.g., about 1 second) to temporarily reduce the pressure in the area upstream of the on-off valves AV204 and AV205 of the second branch supply lines 236A and 236B and the area connected thereto (the area with a thick dotted line). The technical significance of this pressure relief process will be described in detail later.

[0108] [Distribution process (second process)]

[0109] Then, if Fig.6D As shown, the on-off valve AV202 is closed, the on-off valves AV201, AV204, AV205, AV207, AV208, and AV210 are opened, an appropriate initial opening command signal is given to the pressure regulating valve 240, and the opening control of the pressure regulating valve 240 is switched to feedback control, and the process is transferred to the circulation process. The above-mentioned "initial opening" can be, for example, the same opening as the opening when the pressure in the processing container 311 in the above-mentioned supercritical state ensures the pressure stability in the circulation process. The opening of the on-off valve AV210 is preferably performed at the same time as the opening of the on-off valves AV207 and AV208 or later than the opening of the on-off valves AV207 and AV208. With the above-mentioned switching, CO2 is supplied to the processing container 311 via the second supply line 236, the second branch supply lines 236A, 236B and the second fluid release part 322.

[0110] In the circulation process, the pressure in the processing container 311 is maintained at the above-mentioned supercritical state guarantee pressure (16 MPa) by feedback control of the pressure regulating valve 240, and the supercritical CO2 supplied from the second fluid release part 322 to the processing container 311 flows in the upper area of ​​the substrate and is then discharged from the fluid discharge part 324. At this time, a laminar flow of supercritical CO2 is formed in the processing container 311, which flows roughly parallel to the surface of the wafer W. The IPA in the mixed fluid (IPA+CO2) on the surface of the wafer W exposed to the laminar flow of supercritical CO2 is replaced by supercritical CO2. Finally, almost all of the IPA on the surface of the wafer W is replaced by supercritical CO2.

[0111] The mixed fluid consisting of IPA and supercritical CO2 discharged from the fluid discharge part 324 is recovered after flowing through the discharge pipeline 238. The IPA contained in the mixed fluid can be separated and reused. In addition, in the circulation process, the on-off valves AV211 and AV212 can be set to an open state or a closed state according to the required flow rate, etc.

[0112] [Discharging process]

[0113] After the replacement from IPA to supercritical CO2 is completed, Fig. 6E As shown, the on-off valves AV204 and AV205 are closed to stop supplying supercritical CO2 to the processing container 311, and the set pressure of the processing container 311 is reduced to normal pressure. At this time, the on-off valve AV209 of the bypass line 244 may be opened. As a result, the opening of the pressure regulating valve 240 is greatly increased (for example, fully opened), and the pressure in the processing container 311 is reduced to normal pressure. Subsequently, the supercritical CO2 in the pattern of the wafer W becomes gas and detaches from the pattern, and the gaseous CO2 is discharged from the processing container 311 (see the thick dotted line). Instead of reducing the set pressure of the processing container 311 to normal pressure, a command signal for increasing the opening of the pressure regulating valve 240 may be given from the control unit 4 to the pressure regulating valve 240. In the discharge process, the set pressure of the processing container 311 may also be reduced to normal pressure in stages. Thus, the drying of the wafer W is completed.

[0114] [Sending process]

[0115] The plate 315 of the tray 314 carrying the dried wafer W is taken out of the processing container 311 and moved to the substrate transfer position. The wafer W is transferred by the substrate transfer device 18 ( Figure 1 ) is taken out from the plate 315 and sent out from the supercritical drying unit 17. Thus, the supercritical drying process for one wafer is completed.

[0116] [Detailed description of the pressure relief process]

[0117] Next, the pressure relief step (see Figure 6C ) for detailed description. Figure 6B As shown, just before the pressure boosting process (usually the pressure boosting stage) is about to end, CO2 flows from the main supply line 232 to the processing container 311 via the first supply line 234, and a throttling hole OLF is provided in the first supply line 234 (for the sake of convenience, the throttling hole is also referred to as "throttling hole OLF1"), so a pressure drop occurs at the throttling hole OLF1. That is, the pressure in the area upstream of the throttling hole OLF1 (the pressure in the pipeline) is higher than the pressure in the processing container 311 (the pressure in the container). When the flow of CO2 through the throttling hole OLF1 stops, the pressure difference between the upstream and downstream areas of the throttling hole OLF1 gradually decreases, but does not immediately become zero. The upstream area of ​​the throttling hole OLF1 is, for example, a pressure slightly lower than the CO2 delivery pressure of the supercritical fluid supply device 230, which is 20MPa. In addition, the detection pressure of the pressure sensor PS201 at this time is about 19MPa (also refer to Figure 7 The pressure in the downstream area of ​​the orifice OLF1 becomes substantially equal to the pressure increase target pressure (16 MPa) of the processing container.

[0118] Sometimes, the IPA liquid film on the wafer W contains (or dissolves) contaminants. Contaminants include: substances attached to the wafer W before processing by the liquid processing unit 16, substances attached in the liquid processing unit 16, substances attached during transportation, etc. When the pressurization process is implemented, the IPA containing contaminants or dissolved IPA detaches from the IPA liquid film on the wafer W, floats in the processing container 311, and invades the internal space of the tube 322a of the second fluid release part 322 (the pressure in this space is approximately normal pressure at the beginning of the pressurization process). In addition, by repeatedly processing the wafer W in the processing container 311, contaminants adhere to and accumulate on the inner wall of the tube 322a. The accumulation of contaminants on the inner wall of the tube 322a is inevitable. When the pressurization process is implemented, the CO2 supplied to the processing container 311 also invades the interior of the tube 322a. When the internal pressure of the tube 322a increases in the later stage of the pressure increasing process and CO2 inside the tube 322a reaches a critical state, at least a part of the pollutants existing inside the tube 322a dissolves into CO2.

[0119] The higher the density of supercritical CO 2 (ie, the higher the pressure of supercritical CO 2), the greater the amount of pollutants dissolved in supercritical CO 2. Therefore, the solubility of pollutants present inside the tube 322a in supercritical CO 2 becomes maximum at the final stage of the pressure increase process.

[0120] Here, it is assumed that the pressure is not released and the pressure is transferred from the pressure increasing process to the circulation process. In this case, if the on-off valves AV204 and AV205 are opened, the supercritical CO2 of the upstream high pressure (e.g., about 18 to 19 MPa) flows into the pipe 322a of which the pressure is approximately the same as the pressure in the processing container 311 (e.g., about 16 MPa). As a result, the CO2 pressure (i.e., CO2 density) in the pipe 322a rises rapidly, and part of the pollutants in the pipe 322a that have not been dissolved in the supercritical CO2 are dissolved ("additional dissolution") and released into the processing container 311. Furthermore, due to the large pressure difference (about 2 to 3 MPa) between the pipe 322a and the processing container 311, CO2 is sprayed violently from the release port 322b of the pipe 322a. At this time, the pollutants in the pipe 322a are likely to flow into the pipe 322a together with the CO2.

[0121] During the initial release from the tube 322a, the high-pressure CO2 in the tube 322a is released into the low-pressure processing container 311, causing the pressure of CO2 to drop rapidly. As a result, the solubility of the pollutants in CO2 decreases, and the pollutants dissolved in CO2 precipitate. The precipitated pollutants may adhere to the wafer W and contaminate the wafer W. In addition, when CO2 flows stably at a relatively large flow rate through the processing container 311 after the circulation process starts, the pressure in the main supply line 232 decreases (see Figure 7 Therefore, the large pressure difference between the internal space of the processing container 311 and the internal space of the pipe 322a is eliminated. That is, the above-mentioned problem is a problem that occurs only at the beginning of the circulation process.

[0122] By performing the pressure relief process, the above-mentioned problem can be solved. First, by performing the pressure relief process, the above-mentioned "additional dissolution" is less likely to occur. Near the time when CO2 release starts, the difference between the pressure in the processing container 311 and the pressure in the tube 322a becomes smaller, so it is possible to prevent CO2 from being violently sprayed from the release port 322b. In addition, the pollutants from the CO2 released from the tube 322a into the processing container 311 are not likely to precipitate. Therefore, the possibility of wafer W being contaminated is reduced.

[0123] Regarding the pressure relief process, the pressure relief process is performed so that as a result of the pressure relief process, the pressure of the area on the upstream side closest to the opening and closing valves AV204 and AV205 is higher than the pressure in the processing container 311 by 2 MPa or less, preferably higher than 1 MPa or less. As described above, when the pressure increase target pressure is set to 16 MPa, the pressure relief process can be performed so that the pressure of the area on the upstream side closest to the opening and closing valves AV204 and AV205 becomes, for example, about 17 MPa to 18 MPa. In addition, since a backflow of CO2 is generated, the pressure of the area on the upstream side closest to the opening and closing valves AV204 and AV205 cannot be lower than the pressure in the processing container 311.

[0124] The pressure relief process may also be performed by a pressure sensor (for example, pressure sensor P201 (see Figure 1 The process ends when the detected value of the pressure sensor P201 is lower than the predetermined value. A pressure sensor (e.g., Figure 5 The pressure sensor P205 indicated by a dotted line in FIG. 1 ends when the detection value of the pressure sensor becomes lower than a predetermined value (eg, 17 MPa).

[0125] exist Figure 7The graph shows an example of the change in the detection value of the pressure sensor PS201 (corresponding to the pressure on the upstream side of the on-off valves AV204 and AV205) before and after the pressure relief process and the change in the detection value of the pressure sensor PS203 (corresponding to the pressure inside the processing container 311). The vertical axis of the graph is the detection pressure of the pressure sensor (unit: MPa), and the horizontal axis is time (5 seconds in the graph). Lines PS201-1 and PS203-1 respectively show the change in the detection values ​​of the pressure sensors PS201 and PS203 when the pressure relief process is not performed (comparative example). In addition, lines PS201-2 and PS203-2 respectively show the change in the detection values ​​of the pressure sensors PS201 and PS203 when the pressure relief process is performed (implementation). In the graph, the period of about 1 second sandwiched by two vertical dotted lines represents the period during which the pressure relief process is implemented (the period during which the on-off valve AV202 is open). In addition, in Figure 7 In the example, the period to the left of the interval PR corresponds to the end period of the pressure-increasing process (usually the pressure-increasing stage), and the period to the right of the interval PR corresponds to the initial period of the circulation process. Figure 7 As can be seen from the curve graph, by implementing the pressure relief process for about 1 second, the pressure on the upstream side of the on-off valves AV204 and AV205 is reduced by about 2 MPa.

[0126] According to the above-mentioned embodiment, by implementing the pressure relief process, the amount of particles existing on the surface of the wafer W after the supercritical drying process can be greatly reduced. According to the experiment, it was confirmed that by implementing the pressure relief process, the amount of particles larger than 19nm can be reduced by hundreds of units (the ratio of the number can be reduced to about 1 / 3 to 1 / 4) compared with the case where the pressure relief process is not implemented. In addition, it was confirmed that when CO2 is supplied using a strip nozzle in the circulation process, particles are mostly concentrated on one side (left or right) of the wafer W, but such uneven particle generation will not occur.

[0127] [First Modification of Pressure Relief Step and Pressure Boosting Step]

[0128] In the above-described embodiment, the pressure increasing step is continued until the pressure in the processing container 311 reaches the supercritical state ensuring pressure (16 MPa), and then the process is transferred to the flow step, but the present invention is not limited thereto.

[0129] That is, the normal pressure-raising stage of the pressure-raising process may be constituted by the first normal pressure-raising stage (first process) and the second normal pressure-raising stage (second process) thereafter, wherein in the first normal pressure-raising stage, CO2 is supplied to the processing container 311 via the first supply line 234 and the first fluid release part 321, while the pressure in the processing container 311 is raised to an appropriate pressure higher than the critical pressure (about 8 MPa) and lower than the supercritical state guarantee pressure (16 MPa), and in the second normal pressure-raising stage, CO2 is supplied to the processing container 311 via the second supply line 236 and the second fluid release part 322, while the pressure in the processing container 311 is raised to the supercritical state guarantee pressure. Moreover, a pressure relief process (density adjustment process) may be performed between the first normal pressure-raising stage and the second normal pressure-raising stage. The state of each on-off valve in the first normal pressure-raising stage may be the same as that in the normal pressure-raising stage in the above-mentioned embodiment. In addition, the state of each opening and closing valve in the second normal pressure increase stage can be the same as the normal pressure increase stage in the above embodiment, except that the opening and closing valve AV203 is closed and AV204 and AV205 are opened. The pressure relief process can be performed in the same order as the pressure relief process in the above embodiment (which is performed between the pressure increase process and the circulation process). The pressure relief process in this modified embodiment can also be implemented in a manner that the pressure in the area closest to the upstream side of the opening and closing valves AV204 and AV205 is higher than the pressure in the processing container 311 by 2 MPa or less, preferably higher by 1 MPa or less.

[0130] As described above, when the normal pressurization stage of the pressurization process is divided into the first normal pressurization stage (first process) and the second normal pressurization stage (second process), and a pressure relief process (density adjustment process) is performed between the first normal pressurization stage and the second normal pressurization stage, after the second normal pressurization stage is completed (after reaching the supercritical state guarantee pressure), CO2 is started to be discharged from the processing container 311 through the fluid discharge part 324, and the circulation process is transferred to the circulation process.

[0131] As described above, by switching the release part that releases CO2 into the processing container 311 from the first fluid release part 321 to the second fluid release part 322 in advance, and performing a pressure relief process (density adjustment process) when switching, the effect of reducing particles can be improved. That is, at the moment when the release from the second fluid release part 322 begins, the pressure in the processing container 311 is low, so the pressure in the second fluid release part 322 (strip nozzle) is also low. Therefore, since the dissolution of the pollutants in the second fluid release part 322 is suppressed, the pollutants contained in the CO2 released from the second fluid release part 322 can be reduced. In addition, by supplying CO2 into the processing container 311 from the second fluid release part 322 that can release CO2 at a relatively large flow rate after the pressure in the processing container 311 exceeds the critical pressure, the pressure increase process can be performed in a short time.

[0132] [Second Modification of Pressure Relief Step and Pressure Boosting Step]

[0133] The density of supercritical CO2 also changes depending on the temperature. The higher the temperature, the lower the density of supercritical CO2. Therefore, when the pressure relief process is performed, the supercritical CO2 in the area upstream of the opening and closing valves AV204 and AV205 may be heated by a heater instead of the pressure relief process or in addition to the pressure relief process. Thus, the temperature of the supercritical CO2 flowing into the pipe 322a is higher than the temperature of the supercritical CO2 in the processing container 311 immediately after the pressure increase process starts. In other words, the density of the supercritical CO2 flowing into the pipe 322a is lower than the density of the supercritical CO2 in the processing container 311 immediately after the pressure increase process starts. As described above, the solubility of the contaminant is positively correlated with the density of the solvent (supercritical CO2), so the wafer contamination caused by the above mechanism can be suppressed. The density of supercritical CO2 is inversely proportional to the absolute temperature, so when the pressure is changed within the practical temperature range of the supercritical drying process (about 80 to 120°C), the particle suppression effect is high. However, the particle suppression effect can be obtained by adjusting the density only by adjusting the temperature of the supercritical CO 2. In addition, the particle suppression effect can be improved by adjusting the density by not only adjusting the temperature of the supercritical CO 2 but also releasing the pressure.

[0134] When implementing the second variant embodiment described above, it is preferable to be able to independently adjust the temperature of CO2 flowing into the processing container 311 through the first supply line 234 and the temperature of CO2 flowing into the processing container 311 through the second supply line 236. Figure 8 As shown in FIG. 2 , it is preferable to provide heaters H in the first supply line 234 and the second supply line 236 branched from the main supply line 232 instead of providing heaters H in the main supply line 232. Alternatively, as shown in FIG. Fig. 9As shown, instead of branching the first supply line 234 and the second supply line 236 from the main supply line 232, the first supply line 234 and the second supply line 236 may be provided independently of each other, and a heater H may be provided in each of the first supply line 234 and the second supply line 236. In this case, a supercritical fluid supply device may be provided in each of the first supply line 234 and the second supply line 236.

[0135] Therefore, since it is preferable to adjust the temperature of CO2 located near the opening and closing valves AV204 and AV205, a heater of a pipe winding type such as a strip heater or a pipe embedding type may be provided in the piping immediately upstream of the opening and closing valves AV204 and AV205. In addition, a buffer tank including a heater may be provided in the piping immediately upstream of the opening and closing valves AV204 and AV205, and the CO2 heated in the buffer tank may be delivered immediately after the opening and closing valves AV204 and AV205 are opened.

[0136] exist Figure 8 and Fig. 9 In the piping system diagram of the modified embodiment shown, when density adjustment is performed only by temperature adjustment, the exhaust line 233 and the on-off valve AV203 may not be provided.

[0137] In the case of density regulation by pressure relief only, it is also possible to use Figure 8 and Fig. 9 The piping structure shown.

[0138] The structure of the processing container 311 is not limited to Figure 3 and Figure 4 The structure shown, for example, can be used Fig.10 The structure shown. Fig.10 In the variant implementation, the next 3 bits are Figure 3 and Figure 4 Components that are identical to the components shown are components that perform the same functions. Fig.10 The supply / discharge system connected to the processing container 1311 can be directly used Figure 5 , Figure 8 , Fig. 9 The system shown. Fig.10The modified embodiment shown functions as follows. That is, in the pressurization process, CO2 is supplied into the processing container 1311 via the first supply line 234 and the first fluid release part 1321. CO2 just released from the first fluid release part 1321 hits the blocking plate 1340 and does not flow directly to the wafer W. In the flow process, CO2 is supplied into the processing container 1311 via the second supply line 234 and the second fluid release part 1322. The second fluid release part 1322 is provided above the wafer W held in a horizontal posture by the wafer holding part 1321, and releases CO2 to the surface of the wafer W. The CO2 is discharged from the processing container 1311 via the fluid discharge part 1324.

[0139] exist Fig.10 In the modified embodiment shown, by performing the pressure relief step (density adjustment step) when switching from the pressure increasing step (or the first step) to the flow step (or the second step), the particles can be reduced by the same mechanism as described above.

[0140] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, Unless it deviates from the summary, various changes can be made.

[0141] The embodiments described in the specification are illustrative in all aspects and are not to be considered restrictive. In fact, the above embodiments can be implemented in many ways. In addition, the above embodiments can be omitted, replaced, and changed in various ways without departing from the content and gist of the invention.

Claims

1. A substrate processing device, characterized in that: include: A processing container capable of processing a substrate using a processing fluid in a supercritical state; a treatment fluid supply unit for supplying a treatment fluid to the treatment container; and Control Department, The processing fluid supply unit comprises: a first fluid release unit for releasing the processing fluid into the processing container; a second fluid release unit for releasing the processing fluid into the processing container; a first supply line for supplying the treatment fluid to the first fluid release portion; a first on-off valve provided on the first supply line; a second supply line for supplying the treatment fluid to the second fluid release portion; a second on-off valve provided on the second supply line; and a density adjustment mechanism capable of adjusting the density of the treatment fluid located upstream of the second on-off valve of the second supply line, The control unit is configured to control the substrate processing device to perform the following steps: The first step is to open the first on-off valve and close the second on-off valve to supply the processing fluid to the first fluid release part via the first supply line, at least during a first period from when the processing fluid starts to be supplied to the processing container to when the pressure in the processing container rises and the processing fluid in the processing container becomes a supercritical state; a second step of closing the first on-off valve and opening the second on-off valve at least during a second period after the treatment fluid in the treatment container becomes supercritical, and supplying the treatment fluid to the second fluid release portion via the second supply line at a flow rate greater than the flow rate of the treatment fluid supplied from the first supply line to the first fluid release portion during the first period; and A density adjustment process, after the first process is completed and before the second process begins, the density adjustment mechanism is used to make the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold, wherein the density in the pipeline is defined as the density of the treatment fluid in the area upstream of the second on-off valve of the second supply pipeline, and the density in the container is defined as the density of the treatment fluid in the treatment container.

2. The substrate processing device according to claim 1, characterized in that: The density adjustment mechanism includes a pressure adjustment mechanism, The control unit is configured to be able to make the difference between the pressure in the pipeline and the pressure in the container smaller than a predetermined threshold value through the pressure regulating mechanism in the density adjustment process, thereby making the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold value, wherein the pressure in the pipeline is defined as the pressure of the treatment fluid in the area upstream of the second on-off valve of the second supply pipeline, and the pressure in the container is defined as the pressure of the treatment fluid in the treatment container.

3. The substrate processing device according to claim 2, characterized in that: The control unit is configured to open the second on-off valve and start the second step when the pressure in the line is greater than the pressure in the container and the difference between the pressure in the line and the pressure in the container is less than 2 MPa in the density adjustment step.

4. The substrate processing device according to claim 3, characterized in that: The pressure regulating mechanism comprises: a bleed line connected to a region upstream of the second on-off valve of the second supply line; and The on-off valve for deflation provided on the deflation pipeline, The control unit is configured to open the air release on-off valve to reduce the pressure in the pipeline while the first on-off valve and the second on-off valve are closed during the density adjustment process, thereby making the pressure in the pipeline greater than the pressure in the container and the difference between the pressure in the pipeline and the pressure in the container less than 2 MPa.

5. The substrate processing device according to claim 4, characterized in that: Also includes a main supply line connected to a supply source of the treatment fluid in a supercritical state, The first supply line and the second supply line are lines branched from the main supply line at a branch point set in the main supply line. The purge line is connected to the main supply line at a position upstream of the branch point, or is connected to the second supply line between the branch point and the second on-off valve.

6. The substrate processing device according to claim 4, characterized in that: The first supply line and the second supply line are connected to a supply source of a process fluid in a supercritical state, and the gas release line is connected to the second supply line at a position upstream of the second on-off valve.

7. The substrate processing device according to claim 1, characterized in that: The density adjustment mechanism includes a temperature adjustment mechanism, The control unit is configured to make the difference between the temperature in the pipeline and the temperature in the container smaller than a predetermined threshold value through the temperature adjustment mechanism in the density adjustment process, thereby making the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold value, wherein the temperature in the pipeline is defined as the temperature of the treatment fluid in the area upstream of the second on-off valve of the second supply pipeline, and the temperature in the container is defined as the temperature of the treatment fluid in the treatment container.

8. The substrate processing device according to claim 7, characterized in that: The temperature adjustment mechanism includes a heater provided in a region upstream of the second on-off valve of the second supply line.

9. The substrate processing device according to claim 1, characterized in that: The control unit is configured to terminate the first process when the pressure in the processing container becomes a first pressure higher than the critical pressure of the processing fluid, then perform the density adjustment process, and then perform the second process. In the second process, the pressure in the processing container is increased to a second pressure higher than the first pressure.

10. The substrate processing device according to claim 1, wherein: The processing container further includes a substrate holding portion, which holds the substrate having the liquid film formed on the surface thereof horizontally in such a manner that the surface faces upward. The first fluid release portion is configured to release the processing fluid into the processing container from below the substrate held by the substrate holding portion. The second fluid releasing portion is provided to release the processing fluid into the processing container from a side of the substrate held by the substrate holding portion.

11. A substrate processing method, which is a substrate processing method performed using a substrate processing device, wherein the substrate processing method is characterized in that: The substrate processing device comprises: A processing container capable of processing a substrate using a processing fluid in a supercritical state; a treatment fluid supply unit for supplying a treatment fluid to the treatment container; and Control Department, The processing fluid supply unit comprises: a first fluid release unit for releasing the processing fluid into the processing container; a second fluid release unit for releasing the processing fluid into the processing container; a first supply line for supplying the treatment fluid to the first fluid release portion; a first on-off valve provided on the first supply line; a second supply line for supplying the treatment fluid to the second fluid release portion; a second on-off valve provided on the second supply line; and a density adjustment mechanism capable of adjusting the density of the treatment fluid located upstream of the second on-off valve of the second supply line, The substrate processing method comprises: The first step is to open the first on-off valve and close the second on-off valve to supply the processing fluid to the first fluid release part via the first supply line, at least during a first period from when the processing fluid starts to be supplied to the processing container to when the pressure in the processing container rises and the processing fluid in the processing container becomes a supercritical state; a second step of closing the first on-off valve and opening the second on-off valve at least during a second period after the treatment fluid in the treatment container becomes supercritical, and supplying the treatment fluid to the second fluid release portion via the second supply line at a flow rate greater than the flow rate of the treatment fluid supplied from the first supply line to the first fluid release portion during the first period; and A density adjustment process, after the first process is completed and before the second process begins, the density adjustment mechanism is used to make the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold, wherein the density in the pipeline is defined as the density of the treatment fluid in the area upstream of the second on-off valve of the second supply pipeline, and the density in the container is defined as the density of the treatment fluid in the treatment container.

12. The substrate processing method according to claim 11, characterized in that: The density adjustment mechanism includes a pressure adjustment mechanism, The density adjustment process, through the pressure adjustment mechanism, makes the difference between the pressure in the pipeline and the pressure in the container smaller than a predetermined threshold value, thereby making the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold value, wherein the pressure in the pipeline is defined as the pressure of the treatment fluid in the area upstream of the second on-off valve of the second supply pipeline, and the pressure in the container is defined as the pressure of the treatment fluid in the treatment container.

13. The substrate processing method according to claim 12, characterized in that: When the density adjustment step makes the pressure in the line greater than the pressure in the container and the difference between the pressure in the line and the pressure in the container is less than 2 MPa, the second on-off valve is opened to start the second step.

14. The substrate processing device according to claim 13, characterized in that: The pressure regulating mechanism comprises: a bleed line connected to a region upstream of the second on-off valve of the second supply line; and The on-off valve for deflation provided on the deflation pipeline, The density adjustment process is to open the air release valve to reduce the pressure in the pipeline while the first on-off valve and the second on-off valve are closed, thereby making the pressure in the pipeline greater than the pressure in the container and the difference between the pressure in the pipeline and the pressure in the container less than 2MPa.

15. The substrate processing method according to claim 14, characterized in that: The substrate processing device further comprises a main supply line connected to a supply source of a processing fluid in a supercritical state, The first supply line and the second supply line are lines branched from the main supply line at a branch point set in the main supply line. The purge line is connected to the main supply line at a position upstream of the branch point, or is connected to the second supply line between the branch point and the second on-off valve.

16. The substrate processing method according to claim 14, wherein: The first supply line and the second supply line are connected to a supply source of a process fluid in a supercritical state, and the gas release line is connected to the second supply line at a position upstream of the second on-off valve.

17. The substrate processing method according to claim 11, wherein: The density adjustment mechanism includes a temperature adjustment mechanism, The density adjustment process makes the difference between the temperature in the pipeline and the temperature in the container smaller than a predetermined threshold value through the temperature adjustment mechanism, thereby making the difference between the density in the pipeline and the density in the container smaller than a predetermined threshold value, wherein the temperature in the pipeline is defined as the temperature of the treatment fluid in the area upstream of the second on-off valve of the second supply pipeline, and the temperature in the container is defined as the temperature of the treatment fluid in the treatment container.

18. The substrate processing method according to claim 17, wherein: The temperature adjustment mechanism includes a heater provided in a region upstream of the second on-off valve of the second supply line.

19. The substrate processing method according to claim 11, wherein: The first step is terminated when the pressure in the processing container reaches a first pressure higher than the critical pressure of the processing fluid, followed by the density adjustment step, and then the second step, in which the pressure in the processing container is increased to a second pressure higher than the first pressure.

20. The substrate processing method according to claim 11, characterized in that: The substrate processing apparatus further includes a substrate holding portion which holds the substrate having the liquid film formed on the surface thereof horizontally in the processing container so that the surface faces upward. The first fluid release portion is configured to release the processing fluid into the processing container from below the substrate held by the substrate holding portion. The second fluid releasing portion is provided to release the processing fluid into the processing container from a side of the substrate held by the substrate holding portion.

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