Substrate processing device and substrate processing method

Abstract

The present invention provides a substrate processing device and a substrate processing method capable of suppressing the collapse of a pattern formed on the surface of a substrate. The substrate processing device performs: a process of supplying a processing fluid into a processing container containing a substrate with a liquid attached to the surface to increase the pressure in the processing container to a processing pressure higher than the critical pressure of the processing fluid; a process of supplying the processing fluid to the processing container while maintaining the pressure in the processing container at a pressure that maintains the processing fluid in a supercritical state, and discharging the processing fluid from the processing container. The former includes: a process of increasing the pressure in the processing container to a first pressure that is higher than the critical pressure and lower than the processing pressure; a process of increasing the pressure in the processing container from the first pressure to the processing pressure. In the process of increasing the pressure in the processing container to the first pressure, the temperature of the substrate is controlled to a first temperature, and in the process of increasing the pressure to the processing pressure, the temperature of the substrate is controlled to a second temperature higher than the first temperature.

Description

Technical Field

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

[0002] In the manufacturing process of semiconductor devices in which a stacked structure of an integrated circuit is formed on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as a wafer), liquid treatment such as chemical solution cleaning or wet etching is performed. In recent years, a drying method using a processing fluid in a supercritical state has been adopted to remove liquids attached to the surface of the wafer during such liquid treatment.

[0003] Patent Document 1 discloses a substrate processing apparatus including a first fluid supply unit provided below a substrate held by a substrate holding unit and a second fluid supply unit provided beside the substrate held by the substrate holding unit.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-74103 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The present disclosure provides a substrate processing apparatus and a substrate processing method capable of suppressing the collapse of a pattern formed on a surface of a substrate.

[0009] Solutions for solving problems

[0010] A substrate processing device according to a technical solution of the present disclosure is a substrate processing device that uses a processing fluid in a supercritical state to dry a substrate with liquid attached to the surface, wherein the substrate processing device comprises: a processing container that accommodates the substrate; a substrate holding part that holds the substrate horizontally in the processing container in a manner such that the surface faces upward; a fluid supply part that supplies the processing fluid into the processing container; a fluid discharge part that discharges the processing fluid from the processing container; and a control part that at least controls the operations of the fluid supply part and the fluid discharge part and the temperature of the substrate held by the substrate holding part, wherein the control part performs the following steps by controlling the operations of the fluid supply part and the fluid discharge part: supplying the processing fluid into the processing container that accommodates the substrate with liquid attached to the surface so that the pressure in the processing container rises to a level higher than the critical pressure of the processing fluid The process of increasing the pressure in the processing container to the processing pressure comprises the following steps: increasing the pressure in the processing container to a first pressure which is higher than the critical pressure and lower than the processing pressure; and increasing the pressure in the processing container from the first pressure to the processing pressure, the control unit controls the temperature of the substrate to a first temperature in the process of increasing the pressure in the processing container to the first pressure, and the control unit controls the temperature of the substrate to a second temperature which is higher than the first temperature in the process of increasing the pressure in the processing container to the processing pressure.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to suppress the collapse of a pattern formed on the surface of a substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional plan view showing the overall structure of the substrate processing system.

[0014] Figure 2 This is a perspective view of the appearance of a processing container of a supercritical processing device.

[0015] Figure 3 is a cross-sectional view of a processing vessel.

[0016] Figure 4 This is a piping system diagram of a supercritical treatment device.

[0017] Figure 5(a) to (d) are diagrams for explaining the drying mechanism of IPA.

[0018] Figure 6 It is a piping system diagram of a supercritical processing apparatus included in the substrate processing apparatus according to the first embodiment.

[0019] Figure 7 This is a diagram (part 1) showing an outline of the drying method in the first embodiment.

[0020] Figure 8 This is a diagram (part 2) showing the outline of the drying method in the first embodiment.

[0021] Fig. 9 This is a diagram (part 3) showing the outline of the drying method in the first embodiment.

[0022] Fig.10 This is a diagram (part 4) showing the outline of the drying method in the first embodiment.

[0023] Fig.11 (a) and (b) are views showing a holding plate included in the substrate processing apparatus according to the second embodiment.

[0024] Fig.12 (a) to (d) are schematic diagrams showing the contents of experiments related to cleaning efficiency.

[0025] Fig.13 (a) and (b) are graphs showing changes in pressure during cleaning. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In each of the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals and their description may be omitted.

[0027] [Structure of substrate processing system]

[0028] like Figure 1 As shown, the substrate processing system 1 includes: a plurality of cleaning devices 2 (in Figure 1 In the example shown, there are two cleaning devices 2) that supply cleaning liquid to the wafer W to perform cleaning treatment; and a plurality of supercritical processing devices 3 (in Figure 1 In the example shown, there are six supercritical processing devices 3) which remove the liquid for preventing drying (IPA: isopropyl alcohol in this embodiment) attached to the wafer W after the cleaning process by contacting it with a processing fluid in a supercritical state (CO2: carbon dioxide in this embodiment).

[0029] In the substrate processing system 1, a FOUP (Front-Opening Unified Pod) 100 is placed on a loading section 11, and wafers W contained in the FOUP 100 are transferred to a cleaning section 14 and a supercritical processing section 15 by means of a transfer section 12 and a transfer section 13. In the cleaning section 14 and the supercritical processing section 15, first, the wafers W are transferred to a cleaning device 2 disposed in the cleaning section 14 to undergo a cleaning process, and then are transferred to a supercritical processing device 3 disposed in the supercritical processing section 15 to undergo a drying process to remove IPA from the wafers W. Figure 1 In the figure, reference numeral "121" indicates a first conveying mechanism for conveying wafer W between FOUP100 and the transfer section 13, and reference numeral "131" indicates a transfer rack, which serves as a buffer section for temporarily placing wafer W conveyed between the loading and unloading section 12, the cleaning processing section 14 and the supercritical processing section 15.

[0030] The opening of the interface 13 is connected to a wafer conveying path 162, and a cleaning processing section 14 and a supercritical processing section 15 are arranged along the wafer conveying path 162. In the cleaning processing section 14, one cleaning device 2 is arranged across the wafer conveying path 162, and a total of two cleaning devices 2 are arranged. On the other hand, in the supercritical processing section 15, three supercritical processing devices 3 are arranged across the wafer conveying path 162, and a total of six supercritical processing devices 3 are arranged. The supercritical processing device 3 functions as a substrate processing device for performing a drying process to remove IPA from the wafer W. A second conveying mechanism 161 is arranged on the wafer conveying path 162, and the second conveying mechanism 161 is configured to be movable within the wafer conveying path 162. The wafer W placed on the transfer rack 131 is received by the second conveying mechanism 161, and the second conveying mechanism 161 delivers the wafer W to the cleaning device 2 and the supercritical processing device 3. In addition, the number and configuration of the cleaning devices 2 and the supercritical processing devices 3 are not particularly limited. An appropriate number of cleaning devices 2 and supercritical processing devices 3 are configured in an appropriate manner based on the number of wafers W processed per unit time and the processing time of each cleaning device 2 and each supercritical processing device 3.

[0031] The cleaning device 2 is configured as a single-sheet device that cleans the wafers W one by one by using, for example, spin cleaning. In this case, the wafer W can be rotated around a vertical axis while being held horizontally, while a chemical solution for cleaning and a rinse liquid for rinsing the chemical solution are supplied to the processing surface of the wafer W at an appropriate time, thereby performing a cleaning process on the wafer W. The chemical solution and rinse liquid used in the cleaning device 2 are not particularly limited. For example, SC1 liquid (i.e., a mixture of ammonia, hydrogen peroxide, and water) as an alkaline chemical solution can be supplied to the wafer W to remove particles and organic contaminants from the wafer W. Thereafter, deionized water (DIW: DeIonized Water) can be supplied to the wafer W as a rinse liquid to rinse the SC1 liquid from the wafer W. Furthermore, a dilute hydrofluoric acid aqueous solution (DHF: Diluted HydroFluoric acid) as an acidic chemical solution can be supplied to the wafer W to remove the natural oxide film, and thereafter, DIW can also be supplied to the wafer W to rinse the dilute hydrofluoric acid aqueous solution from the wafer W.

[0032] After the cleaning device 2 finishes the rinsing process by DIW, IPA is supplied to the wafer W as a liquid for preventing drying while the wafer W is rotated, and the DIW remaining on the processing surface of the wafer W is replaced with IPA. After that, the rotation of the wafer W is slowly stopped. At this time, a sufficient amount of IPA is supplied to the wafer W, and the surface of the wafer W on which the semiconductor pattern is formed is filled with liquid IPA, and a liquid film of IPA is formed on the surface of the wafer W. The wafer W is kept filled with liquid IPA and is sent out from the cleaning device 2 by the second conveying mechanism 161.

[0033] The IPA thus applied to the surface of the wafer W plays a role in preventing the wafer W from drying. In particular, the so-called pattern collapse on the wafer W due to evaporation of IPA during the transportation of the wafer W from the cleaning device 2 to the supercritical processing device 3 is prevented. Therefore, the cleaning device 2 applies a sufficient amount of IPA to the wafer W so that an IPA film with a relatively large thickness is formed on the surface of the wafer W.

[0034] The wafer W conveyed from the cleaning apparatus 2 is conveyed into the processing container of the supercritical processing apparatus 3 by the second conveying mechanism 161 in a state filled with liquid IPA, and is subjected to a drying process of the IPA in the supercritical processing apparatus 3 .

[0035] [Supercritical treatment equipment]

[0036] Below, refer to Figure 2 to Figure 4 A configuration common to each embodiment of the supercritical processing apparatus 3 will be described.

[0037] like Figure 2 and Figure 3As shown, the processing container 301 includes: a container body 311, which is formed with an opening portion 312 for carrying in and out the wafer W; a retaining plate 316, which holds the wafer W to be processed horizontally; and a cover member 315, which supports the retaining plate 316 and closes the opening portion 312 when the wafer W is carried into the container body 311.

[0038] The container body 311 is a container having a processing space formed therein that can accommodate, for example, a wafer W having a diameter of 300 mm. A fluid supply manifold 317 is provided at one end side of the interior of the container body 311, and a fluid discharge manifold 318 is provided at the other end side. In the example shown in the figure, the fluid supply manifold 317 is composed of a block provided with many openings, and the fluid discharge manifold 318 is composed of a pipe provided with many openings (fluid discharge ports). It is preferred that the first fluid supply port of the fluid supply manifold 317 is located at a position slightly higher than the upper surface of the wafer W held by the holding plate 316.

[0039] The structures of the fluid supply header 317 and the fluid discharge header 318 are not limited to the illustrated example. For example, the fluid discharge header 318 may be formed of a block, and the fluid supply header 317 may be formed of a tube.

[0040] When the holding plate 316 is viewed from below, the holding plate 316 covers substantially the entire area of ​​the lower surface of the wafer W. The holding plate 316 has an opening 316a at the end portion on the cover member 315 side. The processing fluid in the space above the holding plate 316 is guided to the fluid discharge manifold 318 through the opening 316a (see FIG. Figure 3 arrow F5).

[0041] The fluid supply manifold 317 supplies the processing fluid into the container body 311 (processing container 301) in a substantially horizontal direction. The horizontal direction here is a direction perpendicular to the vertical direction in which gravity acts, and is generally a direction parallel to the direction in which the flat surface of the wafer W held on the holding plate 316 extends.

[0042] The fluid in the processing container 301 is discharged to the outside of the processing container 301 through the fluid discharge manifold 318. The fluid discharged through the fluid discharge manifold 318 includes, in addition to the processing fluid supplied into the processing container 301 through the fluid supply manifold 317, IPA attached to the surface of the wafer W and dissolved in the processing fluid.

[0043] A fluid supply nozzle 341 for supplying a processing fluid into the processing container 301 is provided at the bottom of the container body 311. In the illustrated example, the fluid supply nozzle 341 is formed by an opening penetrating the bottom wall of the container body 311. The fluid supply nozzle 341 is located below (e.g., directly below) the center of the wafer W, and supplies the processing fluid into the processing container 301 toward the center of the wafer W (e.g., vertically upward).

[0044] The processing container 301 is also provided with a pressing mechanism (not shown). The pressing mechanism overcomes the internal pressure caused by the supercritical processing fluid supplied into the processing space and presses the cover member 315 toward the container body 311, thereby sealing the processing space. In addition, it is preferred that a heat insulating material, a belt heater, etc. (not shown) are provided on the top wall and the bottom wall of the container body 311 so that the processing fluid supplied into the processing space can maintain the temperature of the supercritical state.

[0045] like Figure 4 As shown, the supercritical treatment device 3 has a fluid supply tank 51 as a supply source of the treatment fluid. The fluid supply tank 51 is connected to a main supply line 50. The main supply line 50 is branched into a first supply line 63 connected to the fluid supply manifold 317 in the treatment container 301 and a second supply line 64 connected to the fluid supply nozzle 341.

[0046] Between the fluid supply tank 51 and the fluid supply manifold 317 (that is, between the main supply line 50 and the first supply line 63 connected thereto), a vaporizer 71 and an on-off valve 55a are provided in order from the upstream side. The vaporizer 71 vaporizes the processing fluid supplied from the fluid supply tank 51 and supplies a gas of a predetermined temperature to the downstream side. The second supply line 64 branches from the main supply line 50 at a position between the vaporizer 71 and the on-off valve 55a. The second supply line 64 is provided with an on-off valve 55b.

[0047] A discharge line 65 is connected to the fluid discharge manifold 318 in the processing container 301. An on-off valve 55c and a pressure regulating valve 55d are provided in the discharge line 65 in order from the upstream side. The opening of the pressure regulating valve 55d is adjusted by the control unit 4. The control unit 4 performs, for example, PID control (Proportional-Integral-Differential Controller) of the opening of the pressure regulating valve 55d.

[0048] A line heater H1 is provided between the vaporizer 71 and the on-off valve 55a and the on-off valve 55b. Line heaters H2 and H3 are provided between the on-off valve 55b and the fluid supply nozzle 341. The line heater H2 is provided at an upstream side of the line heater H3. A line heater H4 is provided between the on-off valve 55a and the fluid supply header 317. The set temperatures of the line heaters H1 to H4 can be independently controlled by the control unit 4.

[0049] Pressure sensors for detecting the pressure in the pipeline and temperature sensors for detecting the temperature of the fluid are installed at various locations such as pipelines for the flow of fluid in the supercritical processing device 3. In addition, a pressure sensor 53 for detecting the pressure in the processing container 301 and a temperature sensor 54 for detecting the temperature of the fluid in the processing container 301 are installed.

[0050] The control unit 4 Figure 4 The various sensors shown (pressure sensor 53, temperature sensor 54, etc.) receive measurement signals and send control signals (opening and closing signals of opening and closing valves 55a~55c, opening signals of pressure regulating valve 55d, etc.) to various functional elements. The control unit 4 is, for example, a computer, which has a calculation unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various processes to be performed in the substrate processing system 1. The calculation unit 18 controls the operation of the substrate processing system 1 by reading out and executing the program stored in the storage unit 19. The program is a program recorded on a storage medium that can be read by a computer, and can also be a program loaded from the storage medium to the storage unit 19 of the control unit 4. As a storage medium that can be read by a computer, there are, for example, a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), a memory card, etc.

[0051] [Supercritical drying treatment]

[0052] Next, refer to Figure 5 (a) to (d) briefly illustrate the drying mechanism of IPA using a processing fluid in a supercritical state (such as carbon dioxide (CO2)).

[0053] After the supercritical processing fluid R is introduced into the processing container 301, Figure 5 As shown in (a), IPA exists only in the concave portion of the pattern P on the wafer W.

[0054] The IPA in the concave portion gradually dissolves in the processing fluid R by contacting with the processing fluid R in a supercritical state. Figure 5 As shown in (b), the liquid is gradually replaced with the treatment fluid R. At this time, in addition to IPA and the treatment fluid R, a mixed fluid M in which IPA and the treatment fluid R are mixed exists in the concave portion.

[0055] As the replacement of IPA to the treatment fluid R progresses in the recess, the IPA present in the recess decreases, and eventually Figure 5 As shown in (c), only the processing fluid R in a supercritical state exists in the recess.

[0056] After the IPA is removed from the recess, the pressure in the processing container 301 is reduced to atmospheric pressure, so that Figure 5 As shown in (d), the processing fluid R changes from a supercritical state to a gas state, and the concave portion is occupied only by the gas. In this way, the IPA in the concave portion of the pattern P is removed, and the drying process of the wafer W is completed.

[0057] On the other hand, in the drying process using the processing fluid R of the substrate processing system 1 described above, pattern collapse sometimes occurs. The inventors of the present application have repeatedly conducted in-depth research on the cause of pattern collapse, and as a result, it has been found that before the IPA in the recess is replaced by the processing fluid R, the temperature of the IPA in the recess rises due to the heat of the processing fluid R, and a part of the IPA evaporates. In addition, it has been found that when the temperature of the processing fluid R is set to a temperature at which it is difficult for IPA to evaporate and the drying process is performed, IPA is difficult to dissolve in the processing fluid R in a supercritical state, and IPA is not fully replaced by the processing fluid R in a supercritical state, so that pattern collapse is likely to occur.

[0058] Based on these insights, the inventors of the present application have further repeatedly conducted in-depth research, and as a result, have also found out that by appropriately adjusting the temperature of the wafer W during the period of increasing the pressure in the processing container 301, the temperature increase and evaporation of the IPA before replacement can be suppressed, and the pattern collapse can be suppressed. For example, it has been found out that the temperature of the wafer W is set to a first temperature until the pressure in the processing container 301 reaches a preset first pressure, and after the pressure in the processing container 301 reaches the first pressure, the temperature of the wafer W is set to a second temperature higher than the first temperature, so that the pattern collapse can be suppressed.

[0059] The first temperature can be set to a temperature at which IPA is difficult to evaporate before replacement, for example, 80° C. to 90° C. The second temperature can be set to a temperature at which IPA is easily dissolved in the treatment fluid R in a supercritical state, for example, 100° C. to 120° C. The first pressure can be set to a pressure higher than the critical pressure of the treatment fluid R. When CO2 is used as the treatment fluid R, the critical pressure of CO2 is about 7 MPa, and the first pressure can be set to about 8 MPa, for example.

[0060] (First embodiment)

[0061] A substrate processing apparatus according to a first embodiment having a structure suitable for adjusting the temperature of a wafer W will be described. Figure 6It is a piping system diagram of a supercritical processing apparatus included in the substrate processing apparatus according to the first embodiment.

[0062] like Figure 6 As shown, the supercritical processing device 300 provided in the substrate processing device of the first embodiment has Figure 4 In addition to the structure of the supercritical treatment device 3 shown, it also has a fluid supply tank 52 as a supply source of the treatment fluid. The third supply line 66 is connected to the fluid supply tank 52. The third supply line 66 is connected to the second supply line 64 at a position downstream of the on-off valve 55b. In other words, the third supply line 66 is connected to the fluid supply nozzle 341.

[0063] Between the fluid supply tank 52 and the fluid supply nozzle 341 (that is, the third supply line 66), a vaporizer 72 and an on-off valve 55e are provided in order from the upstream side. The vaporizer 72 vaporizes the processing fluid supplied from the fluid supply tank 52 and supplies a gas of a predetermined temperature to the downstream side. The third supply line 66 is connected to the second supply line 64 at a position downstream of the on-off valve 55e.

[0064] A line heater H6 is provided between the vaporizer 72 and the on-off valve 55e. A line heater H5 is provided between the portion where the third supply line 66 is connected to the second supply line 64 and the on-off valve 55e. The set temperatures of the line heaters H5 and H6 can be independently controlled by the control unit 4.

[0065] For example, the first path includes a portion of the second supply line 64 and the third supply line 66. The vaporizer 72 is an example of the first vaporizer. For example, the second path includes the main supply line 50, the first supply line 63, and the second supply line 64. The vaporizer 71 is an example of the second vaporizer. For example, the first fluid supply unit includes the main supply line 50, the second supply line 64, the third supply line 66, and the fluid supply nozzle 341. For example, the second fluid supply unit includes the main supply line 50, the first supply line 63, and the fluid supply manifold 317. For example, the fluid discharge unit includes the fluid discharge manifold 318 and the discharge line 65.

[0066] In the first embodiment, the vaporizer 71 converts the processing fluid supplied from the fluid supply tank 51 into a gas at a second temperature, for example, 100° C. to 120° C., and the vaporizer 72 converts the processing fluid supplied from the fluid supply tank 52 into a gas at a first temperature, for example, 80° C. to 90° C. The second temperature is higher than the first temperature.

[0067] Next, in the first embodiment, a drying method (substrate processing method) performed using the supercritical processing apparatus 300 is described. The drying method described below is automatically performed under the control of the control unit 4 based on the processing recipe and control program stored in the storage unit 19. Figure 7 to Figure 10 It is a diagram showing an outline of the drying method (substrate processing method) in the first embodiment.

[0068] <Feeding process>

[0069] The wafer W that has been cleaned in the cleaning device 2 is conveyed out of the cleaning device 2 by the second conveying mechanism 161 in a state where the recessed portions of the pattern on the surface are filled with IPA and a liquid mass of IPA is formed on the surface. The second conveying mechanism 161 places the wafer W on the holding plate 316, and then the holding plate 316 on which the wafer W is placed enters the container body 311, and the cover member 315 is sealedly engaged with the container body 311. With the above, the conveying of the wafer W is completed.

[0070] After the carrying step, CO 2 , for example, is supplied into the processing container 301 as the processing fluid R, and a drying process of the wafer W using CO 2 is performed.

[0071] <First pressure increasing step>

[0072] First, the first pressure increasing step is performed. In the first pressure increasing step, CO 2 is supplied from the fluid supply tank 52 into the processing container 301 as the processing fluid R. Specifically, Figure 7 As shown in FIG. 5 , the on-off valve 55e is set to an open state, and the on-off valves 55a, 55b, and 55c are set to a closed state. As a result, CO2 at the first temperature is ejected from the fluid supply tank 52 from the fluid supply nozzle 341 located just below the center of the wafer W toward the lower surface of the holding plate 316. By supplying CO2 at the first temperature into the processing container 301, the temperature of the wafer W changes to the first temperature.

[0073] CO2 (see Figure 3 After the arrow F1) collides with the holding plate 316 covering the lower surface of the wafer W, it spreads radially along the lower surface of the holding plate 316 (refer to Figure 3 Then, the liquid flows into the space on the upper surface side of the wafer W through the gap between the edge of the holding plate 316 and the side wall of the container body 311 and the opening 316a of the holding plate 316 (refer to Figure 3 Since the on-off valve 55c is in a closed state, CO 2 does not flow out of the processing container 301. Therefore, the pressure in the processing container 301 gradually increases.

[0074] In the first pressure-increasing step, the pressure of CO2 flowing into the processing container 301 is lower than the critical pressure (e.g., about 7 MPa). Therefore, CO2 flows into the processing container 301 in the state of gas. Afterwards, as the filling of CO2 into the processing container 301 proceeds, the pressure in the processing container 301 gradually increases. If the pressure in the processing container 301 exceeds the critical pressure, the CO2 in the processing container 301 becomes a supercritical state. If the CO2 in the processing container 301 becomes a supercritical state, the IPA on the wafer W begins to dissolve in the supercritical CO2. As a result, the mixing ratio of IPA and CO2 in the mixed fluid composed of CO2 and IPA gradually changes.

[0075] The pressure in the processing container 301 is detected by the pressure sensor 53, and the first pressure increasing step is continued until the pressure in the processing container 301 reaches the first pressure, for example, 8 MPa.

[0076] <Second pressure increasing step>

[0077] When the pressure in the processing container 301 reaches the first pressure, for example, 8 MPa, the first pressure increasing step is terminated and the second pressure increasing step is started. In the second pressure increasing step, the supply path of CO2 to the processing container 301 is changed. Specifically, Figure 8 As shown in FIG. 5 , the on-off valve 55b is set to an open state, and the on-off valves 55a, 55c, and 55e are set to a closed state. As a result, CO2 at the second temperature is ejected from the fluid supply tank 51 from the fluid supply nozzle 341 located just below the center of the wafer W toward the lower surface of the holding plate 316. In other words, the temperature of CO2 supplied into the processing container 301 increases rapidly. By supplying CO2 at the second temperature into the processing container 301, the temperature of the wafer W changes rapidly to the second temperature.

[0078] The mixing ratio of IPA and CO2 may not be uniform over the entire surface of the wafer W. In order to prevent the pattern from collapsing due to the unpredictable vaporization of the mixed fluid, in the second pressure-increasing step, the pressure in the processing container 301 is increased to a pressure that ensures that the CO2 in the processing container 301 is in a supercritical state regardless of the CO2 concentration in the mixed fluid, which is 15 MPa here. Here, "pressure that ensures a supercritical state" refers to a pressure that is higher than the maximum value of the critical pressure in a graph showing the change in critical pressure relative to critical temperature. This pressure (15 MPa) is called the "processing pressure." The first pressure is lower than the processing pressure. While the pressure in the processing container 301 rises from the first pressure (8 MPa) to the processing pressure (15 MPa), CO2 at the second temperature is continuously supplied from the fluid supply nozzle 341 to the processing container 301 via the opening and closing valve 55b.

[0079] <Distribution process>

[0080] After the second pressure-increasing step, a circulation step is performed. In the circulation step, CO2 at the second temperature is supplied from the fluid supply tank 51 to the processing container 301 through the on-off valve 55a and the fluid supply manifold 317. Specifically, Fig. 9 As shown, the on-off valves 55a and 55c are set to an open state, and the on-off valves 55b and 55e are set to a closed state. Thus, CO2 at a second temperature is supplied from the fluid supply tank 51 to the processing container 301 using the fluid supply manifold 317 (see Figure 3 The fluid supply manifold 317 can supply CO2 at a flow rate greater than that of the fluid supply nozzle 341. During the circulation process, the pressure in the processing container 301 is maintained at a pressure sufficiently higher than the critical pressure, so there will be no drying problem even if a large flow of CO2 collides with the surface of the wafer W or flows near the surface of the wafer W. Therefore, the fluid supply manifold 317 is used with emphasis on shortening the processing time. In addition, during the circulation process, the temperature of the wafer W is maintained at the second temperature.

[0081] In the flow process, CO2 is supplied into the processing container 301 through the fluid supply manifold 317, and CO2 is exhausted from the processing container 301 through the fluid exhaust manifold 318, so that a laminar flow of CO2 flowing substantially parallel to the surface of the wafer W is formed in the processing container 301 (see Figure 3 arrow F6).

[0082] By performing the flow process, the replacement of IPA with CO 2 is promoted in the recessed portions of the pattern of the wafer W. As the replacement of IPA with CO 2 in the recessed portions proceeds, the critical pressure of the mixed fluid gradually decreases.

[0083] <Discharging process>

[0084] The flow process completes the replacement of IPA with CO2 in the concave portion of the pattern, and then the discharge process is performed. Fig.10 As shown, the on-off valve 55c is set to an open state, and the on-off valves 55a, 55b and 55e are set to a closed state. If the pressure in the processing container 301 is lower than the critical pressure of CO2 by the exhaust process, the supercritical CO2 gasifies and escapes from the concave portion of the pattern. Thus, the drying process for one wafer W is completed.

[0085] According to the first embodiment, in the first and second pressure increasing steps, CO 2 is supplied into the processing container 301 from the fluid supply nozzle 341 located below the wafer W. Therefore, pattern collapse can be more reliably prevented. This point will be described below.

[0086] If the liquid IPA on the surface of the wafer W is exposed to the flow of gaseous CO2, the IPA evaporates, and pattern collapse may occur. In the first and second pressurization steps, if gaseous CO2 is supplied from the fluid supply manifold 317 located on the side of the wafer W into the processing container 301, the flow of CO2 with a relatively high flow rate directly collides with the liquid mass of IPA or passes near the liquid mass of IPA, so there is a tendency for evaporation of IPA to occur easily.

[0087] In contrast, in the present embodiment, the CO2 ejected from the fluid supply nozzle 341 does not flow directly toward the surface of the wafer W or the space near the surface, but after colliding with the central portion of the lower surface of the retaining plate 316, it radially expands along the lower surface of the retaining plate 316, and then flows into the space on the upper surface side of the wafer W. That is, in the present embodiment, there is no flow of CO2 from the processing fluid ejection port directly toward the surface of the wafer W or the space near the surface. Therefore, the evaporation of IPA caused by the supply of gaseous CO2 into the processing container 301 is greatly suppressed. In addition, when the gaseous CO2 flows into the space on the upper surface side of the wafer W, the flow rate of CO2 is significantly smaller than the flow rate of CO2 when it is ejected from the fluid supply nozzle 341. As a result, the evaporation of IPA is further suppressed.

[0088] In addition, the temperature of CO2 supplied into the processing container 301 in the first pressure increase step is the first temperature at which IPA is difficult to evaporate, so the temperature of the wafer W becomes the first temperature, and IPA is also difficult to evaporate due to the heat of CO2. Therefore, pattern collapse caused by evaporation of IPA can be further suppressed.

[0089] Furthermore, the temperature of CO2 supplied into the processing container 301 in the second pressure increasing step and the flow step is higher than the first temperature, and is the second temperature at which IPA is easily dissolved in the supercritical CO2. Therefore, the temperature of the wafer W becomes the second temperature, which makes IPA easily dissolved in the supercritical CO2. Therefore, pattern collapse caused by insufficient replacement can be suppressed.

[0090] In addition, CO2 of the first temperature is supplied from the vaporizer 72, and CO2 of the second temperature is supplied from the vaporizer 71. Therefore, the temperature of CO2 supplied to the processing container 301 can be changed rapidly, and the temperature of the wafer W can be changed rapidly. By changing the temperature of the wafer W rapidly, the waiting time until the temperature is stabilized can be shortened, ensuring good productivity. In addition, while the temperature of the wafer W is changing, IPA also gradually evaporates. Therefore, the longer the waiting time, the more IPA is likely to evaporate. According to the first embodiment, by changing the temperature rapidly, the waiting time can be shortened and the evaporation of IPA can be suppressed.

[0091] In the first embodiment, CO2 is supplied from the fluid supply nozzle 341 to the processing container 301 throughout the first and second pressurization steps, but the present invention is not limited thereto. For example, in the second pressurization step, CO2 may be supplied from the fluid supply manifold 317 to the processing container 301, or from both the fluid supply manifold 317 and the fluid supply nozzle 341 to the processing container 301. In these cases, pattern collapse can be prevented.

[0092] However, it is preferred that CO2 is supplied only from the fluid supply nozzle 341 into the processing container 301 throughout the entire period spanning the first and second pressure-raising steps, as in the first embodiment. This is because, if CO2 is supplied from the fluid supply manifold 317 into the processing container 301, the supplied CO2 directly collides with the liquid mass composed of IPA or a mixed fluid of IPA and CO2 and stirs the liquid mass, which tends to easily generate particles. In addition, this is because it is possible to more reliably prevent the collapse of the pattern.

[0093] The use of the fluid supply manifold 317 can increase the pressurization speed compared to the use of the fluid supply nozzle 341. Therefore, depending on the required particle level, the fluid supply manifold 317 can be used to supply CO2 into the processing container 301 in the second pressurization step, with an emphasis on productivity.

[0094] (Second embodiment)

[0095] A substrate processing apparatus according to a second embodiment having a structure suitable for adjusting the temperature of the wafer W will be described. Fig.11 (a) and (b) are views showing a holding plate included in the substrate processing apparatus according to the second embodiment. Fig.11 (a) is a top view showing the retaining plate, Fig.11 (b) is a cross-sectional view showing a cooling device for cooling the holding plate.

[0096] The supercritical processing device 3 provided in the substrate processing device of the second embodiment is, for example, Figure 4 The supercritical processing apparatus 3 shown in the figure. In the second embodiment, the vaporizer 71 converts the processing fluid supplied from the fluid supply tank 51 into a gas at a third temperature. The third temperature may be equal to the first temperature or the second temperature, or may be higher than the first temperature and lower than the second temperature.

[0097] like Fig.11As shown in (a), the holding plate 316 provided in the substrate processing apparatus of the second embodiment has a temperature control element 319. The temperature control element 319 is used to adjust the temperature of the holding plate 316. The temperature control element 319 includes, for example, a heater and a Peltier element. The temperature control element 319 is an element capable of adjusting the temperature of at least the holding plate 316 to a first temperature and a second temperature.

[0098] like Fig.11 As shown in (b), the cover member 315 and the holding plate 316 can be located outside the container body 311 during the period of waiting for the transfer of the wafer W. In the second embodiment, there is a cooling device 320 for cooling the holding plate 316 while the holding plate 316 is waiting outside the container body 311. The cooling device 320 is, for example, a blower that blows dry air 321 toward the holding plate 316. The temperature of the dry air 321 is, for example, room temperature such as 10°C to 30°C.

[0099] The position where the temperature adjustment element 319 is set is not limited. Preferably, in order to uniformly adjust the temperature of the wafer W, a plurality of temperature adjustment elements 319 are set at equal intervals along the circumference of the wafer W on a circle equidistant from the center of the wafer W.

[0100] Next, the second embodiment uses Figure 4 The drying method (substrate processing method) performed by the supercritical processing apparatus 3 shown in FIG. 1 is described below. The drying method described below is automatically performed under the control of the control unit 4 based on the processing recipe and control program stored in the storage unit 19.

[0101] <Feeding process>

[0102] As in the first embodiment, the wafer W having the concave portions of the pattern on the surface filled with IPA and having a liquid mass of IPA formed on the surface is placed on the holding plate 316, and then the holding plate 316 on which the wafer W is placed enters the container body 311, and the cover member 315 is sealedly engaged with the container body 311. In addition, until the wafer W is placed, the holding plate 316 is arranged outside the container body 311, and dry air 321 is blown to the holding plate 316 by the cooling device 320. As a result, when the wafer W is placed, the temperature of the holding plate 316 becomes a room temperature of 10°C to 30°C.

[0103] After the carrying step, CO 2 , for example, is supplied into the processing container 301 as the processing fluid R, and a drying process of the wafer W using CO 2 is performed.

[0104] <First pressure increasing step>

[0105] First, the first pressurization process is performed. In the first pressurization process, CO2 as the processing fluid R is supplied from the fluid supply tank 51 to the processing container 301. That is, the on-off valve 55b is set to an open state, and the on-off valves 55a and 55c are set to a closed state. As a result, CO2 at the third temperature is ejected from the fluid supply tank 51 from the fluid supply nozzle 341 located directly below the central portion of the wafer W toward the lower surface of the retaining plate 316. In addition, the control unit 4 controls the output of the temperature regulating element 319 so that the temperature of the retaining plate 316 is adjusted to the first temperature by the temperature regulating element 319. By adjusting the temperature of the retaining plate 316 to the first temperature, the temperature of the wafer W changes to the first temperature. Although the temperature of the wafer W is also affected by the heat of the CO2 supplied to the processing container 301, the temperature of the retaining plate 316 that retains the wafer W has a greater influence on the temperature of the wafer W.

[0106] As in the first embodiment, CO2 is ejected from the fluid supply nozzle 341, so that the pressure in the processing container 301 gradually increases. Furthermore, if the pressure in the processing container 301 exceeds the critical pressure, the CO2 in the processing container 301 becomes supercritical, and the IPA on the wafer W begins to dissolve in the supercritical CO2, and the mixing ratio of IPA and CO2 in the mixed fluid composed of CO2 and IPA gradually changes.

[0107] The pressure in the processing container 301 is detected by the pressure sensor 53, and the first pressure increasing step is continued until the pressure in the processing container 301 reaches the first pressure, for example, 8 MPa.

[0108] <Second pressure increasing step>

[0109] If the pressure in the processing container 301 reaches the first pressure, for example, 8Mpa, the first pressure increasing process ends and turns to the second pressure increasing process. In the second pressure increasing process, the set temperature of the temperature regulating element 319 is changed. Specifically, the set temperature of the temperature regulating element 319 is set to the second temperature, and the control unit 4 controls the output of the temperature regulating element 319 so that the temperature of the holding plate 316 is adjusted to the second temperature by the temperature regulating element 319. As a result, the temperature of the holding plate 316 increases rapidly. As the temperature of the holding plate 316 increases, the temperature of the wafer W changes rapidly to the second temperature. In the second pressure increasing process, the on-off valve 55b remains in an open state, the on-off valves 55a and 55c remain in a closed state, and CO2 at the third temperature is continuously ejected from the fluid supply nozzle 341 toward the lower surface of the holding plate 316 from the fluid supply tank 51.

[0110] In the second embodiment, the pressure in the processing container 301 is also increased to a pressure that ensures that the CO2 in the processing container 301 is in a supercritical state regardless of the CO2 concentration in the mixed fluid, which is 15 MPa in this case. While the pressure in the processing container 301 is increasing from the first pressure (8 MPa) to the processing pressure (15 MPa), CO2 at the third temperature is continuously supplied from the fluid supply nozzle 341 to the processing container 301 via the on-off valve 55b.

[0111] <Distribution process>

[0112] After the second pressure-increasing step, a circulation step is performed. In the circulation step, CO2 at the third temperature is supplied from the fluid supply tank 51 to the processing container 301 via the on-off valve 55a from the fluid supply manifold 317. Specifically, the on-off valves 55a and 55c are set to an open state, and the on-off valve 55b is set to a closed state. Thus, CO2 at the third temperature is supplied from the fluid supply tank 51 to the processing container 301 using the fluid supply manifold 317 (see Figure 3 During the flow process, the set temperature of the temperature control element 319 is maintained at the second temperature, and the temperature of the wafer W is maintained at the second temperature.

[0113] <Discharging process>

[0114] The flow process is used to complete the replacement of IPA with CO2 in the concave portion of the pattern, and then the discharge process is performed. In the discharge process, the on-off valve 55c is set to an open state, and the on-off valves 55a and 55b are set to a closed state. In the discharge process, the temperature regulating element 319 can also be disconnected. In other words, the temperature adjustment of the holding plate 316 can also be stopped. If the pressure in the processing container 301 is lower than the critical pressure of CO2 by the discharge process, the CO2 in the supercritical state is gasified and separated from the concave portion of the pattern. Thus, the drying process for one wafer W is completed.

[0115] After the discharge process, the holding plate 316 on which the wafer W is placed moves out of the container body 311 and delivers the wafer W to the second transport mechanism 161. Then, the cooling device 320 blows dry air 321 to the holding plate 316. As a result, the temperature of the holding plate 316 reaches about room temperature.

[0116] The set temperatures of the heaters H1 to H4 can be set to a constant value during the drying process for one wafer W. The set temperatures of the heaters H1 to H4 may be equal to each other, or may be partially or entirely different from each other.

[0117] According to the second embodiment as well, since the temperature of the wafer W is appropriately adjusted in the first and second pressure increasing steps, the same effects as those of the first embodiment can be obtained.

[0118] In addition, the holding plate 316 is cooled to a temperature around room temperature while the wafer W is on standby, so that the temperature deviation of the holding plate 316 at the start of the first pressurization step can be suppressed. Therefore, during the first pressurization step, the temperature of the holding plate 316 can be easily adjusted to the first temperature.

[0119] (Third embodiment)

[0120] A substrate processing apparatus according to a third embodiment having a structure suitable for adjusting the temperature of the wafer W will be described. As in the second embodiment, the supercritical processing apparatus 3 provided in the substrate processing apparatus according to the third embodiment is, for example, Figure 4 The supercritical processing apparatus 3 shown in FIG. 3 is also a vaporizer 71 that can convert the processing fluid supplied from the fluid supply tank 51 into a gas at the third temperature. In the third embodiment, the set temperatures of the heaters H1 to H4 are appropriately changed.

[0121] In the third embodiment, Figure 4 The drying method (substrate processing method) performed by the supercritical processing apparatus 3 shown in FIG. 1 is described below. The drying method described below is automatically performed under the control of the control unit 4 based on the processing recipe and control program stored in the storage unit 19.

[0122] <Feeding process>

[0123] Similar to the first embodiment, a wafer W having a surface pattern recess filled with IPA and having a liquid mass of IPA formed on its surface is placed on a retaining plate 316. Thereafter, the retaining plate 316 carrying the wafer W enters the container body 311, and the cover member 315 is sealedly engaged with the container body 311.

[0124] After the carrying step, CO 2 , for example, is supplied into the processing container 301 as the processing fluid R, and a drying process of the wafer W using CO 2 is performed.

[0125] <First pressure increasing step>

[0126] First, the first pressure increase process is performed. CO2 as the processing fluid R is supplied from the fluid supply tank 51 to the processing container 301. That is, the on-off valve 55b is set to an open state, and the on-off valves 55a and 55c are set to a closed state. As a result, CO2 is ejected from the fluid supply nozzle 341 located directly below the center of the wafer W from the fluid supply tank 51 toward the lower surface of the retaining plate 316. In addition, the combination of the set temperatures of the heaters H1 to H4 is set to the first combination. The first combination is a combination of the set temperatures of the heaters H1 to H4 so that the temperature of the CO2 supplied to the processing container 301 via the main supply line 50 and the second supply line 64 provided with the heaters H1, H2, and H3 becomes the first temperature. The control unit 4 controls the output of the heaters H1 to H4 to supply CO2 of the first temperature to the processing container 301. By supplying CO2 of the first temperature to the processing container 301, the temperature of the wafer W changes to the first temperature.

[0127] As in the first embodiment, CO2 is ejected from the fluid supply nozzle 341, so that the pressure in the processing container 301 gradually increases. Furthermore, if the pressure in the processing container 301 exceeds the critical pressure, the CO2 in the processing container 301 becomes supercritical, and the IPA on the wafer W begins to dissolve in the supercritical CO2, and the mixing ratio of IPA and CO2 in the mixed fluid composed of CO2 and IPA gradually changes.

[0128] The pressure in the processing container 301 is detected by the pressure sensor 53, and the first pressure increasing step is continued until the pressure in the processing container 301 reaches the first pressure, for example, 8 MPa.

[0129] <Second pressure increasing step>

[0130] If the pressure in the processing container 301 reaches the first pressure, for example, 8 MPa, the first pressure increasing process is terminated and the second pressure increasing process is started. In the second pressure increasing process, the combination of the set temperatures of the heaters H1 to H4 is changed to the second combination. The second combination is a combination of the set temperatures of the heaters H1 to H4 so that the temperature of CO2 supplied to the processing container 301 via the main supply line 50 and the second supply line 64 provided with the heaters H1, H2 and H3 becomes the second temperature. The control unit 4 controls the output of the heaters H1 to H4 to supply CO2 of the second temperature to the processing container 301. By supplying CO2 of the second temperature to the processing container 301, the temperature of the wafer W changes to the second temperature. In the second pressure increasing process, the on-off valve 55b remains in the open state, the on-off valves 55a and 55c remain in the closed state, and CO2 of the third temperature is continuously ejected from the fluid supply nozzle 341 from the fluid supply tank 51 toward the lower surface of the retaining plate 316.

[0131] In the third embodiment, the pressure in the processing container 301 is also increased to a pressure that ensures that the CO2 in the processing container 301 is in a supercritical state regardless of the CO2 concentration in the mixed fluid, which is 15 MPa in this case. While the pressure of CO2 in the processing container 301 is increased from the first pressure (8 MPa) to the processing pressure (15 MPa), CO2 at the second temperature is continuously supplied from the fluid supply nozzle 341 to the processing container 301 via the on-off valve 55b.

[0132] <Distribution process>

[0133] After the second pressurizing step, a circulation step is performed. In the circulation step, CO2 at the third temperature is supplied from the fluid supply tank 51 to the processing container 301 from the fluid supply manifold 317 via the on-off valve 55a. Specifically, the on-off valves 55a and 55c are set to an open state, and the on-off valve 55b is set to a closed state. In addition, the combination of the set temperatures of the heaters H1 to H4 is set to a third combination. The third combination is a combination of the set temperatures of the heaters H1 to H4 that are set so that the temperature of the CO2 supplied to the processing container 301 via the main supply line 50 provided with the heaters H1 and H4 and the first supply line 63 becomes the second temperature. The third combination may also be consistent with the second combination. Thus, CO2 at the second temperature is supplied to the processing container 301 using the fluid supply manifold 317 (refer to Figure 3 During the flow process, the temperature of the wafer W is maintained at the second temperature.

[0134] <Discharging process>

[0135] The flow process is used to complete the replacement of IPA with CO2 in the concave portion of the pattern, and then the exhaust process is performed. In the exhaust process, the on-off valve 55c is set to an open state, and the on-off valves 55a and 55b are set to a closed state. In the exhaust process, the combination of the set temperatures of the heaters H1 to H4 can also be changed to the first combination. If the pressure in the processing container 301 is lower than the critical pressure of CO2 by the exhaust process, the CO2 in the supercritical state is gasified and separated from the concave portion of the pattern. Thus, the drying process for one wafer W is completed.

[0136] According to the third embodiment as well, since the temperature of the wafer W is appropriately adjusted in the first pressure increasing step and the second pressure increasing step, pattern collapse can be suppressed similarly to the first embodiment.

[0137] In the second and third embodiments, it is also possible to use Figure 6 The supercritical processing device 300 shown replaces Figure 4The supercritical processing device 3 shown in the figure. For example, in the first pressure increasing step, the output of the temperature regulating element 319 is controlled while the CO2 of the first temperature is supplied using the vaporizer 72, or the output of the line heaters H1, H2, H3, H5 and H6 is controlled. In addition, the second embodiment and the third embodiment may be combined to control the output of the temperature regulating element 319 while controlling the output of the line heaters H1, H2 and H3.

[0138] (Cleaning method)

[0139] In any embodiment, there is a situation where particles adhere to the wafer during the drying process. The inventors of the present application have repeatedly conducted in-depth research to suppress the adhesion of particles to the wafer. As a result, it was found that it is effective to use a processing fluid in a supercritical state to clean the processing container 301 between drying processes. The inventors of the present application have further conducted in-depth research to improve the cleaning efficiency. As a result, it was found that during cleaning, the cleaning efficiency of repeatedly increasing and decreasing the pressure is excellent compared to maintaining the pressure in the processing container 301 at a constant while allowing the processing fluid to continue to flow.

[0140] An experiment on cleaning efficiency conducted by the inventors of the present application will be described. Fig.12 (a) to (d) are schematic diagrams showing the contents of experiments related to cleaning efficiency.

[0141] First, if Fig.12 As shown in (a) of FIG. 1 , a wafer W having a liquid mass of IPA 41 formed on the surface is placed on the holding plate 316 and the wafer W is transported into the container body 311. Next, as shown in FIG. Fig.12 As shown in (b), IPA41 is gasified by natural drying in the container body 311. A portion of the gasified IPA41 adheres to the container body 311 and the discharge line 65. Fig.12 As shown in (c) of FIG. 1 , the container body 311 and the discharge line 65 were cleaned using the treatment fluid 42. This cleaning was performed in two ways. Fig.13 (a) and (b) are diagrams showing changes in pressure during cleaning. Fig.13 As shown in (a), the pressure in the processing container 301 is maintained at a certain processing pressure while the processing fluid 42 continues to flow. Fig.13 As shown in (b), the pressure of the treatment is repeatedly increased and decreased. Supercritical CO2 is used as the treatment fluid 42. Fig.13 (b) shows an example of repeating 3 times of pressure increase and 3 times of pressure reduction. Fig.12 As shown in (d), a drying process is performed on another wafer W having a liquid mass of IPA 41 formed on the surface. In this drying process, the temperature of the wafer W in the pressure increasing step is kept constant without taking the pattern collapse into consideration.

[0142] Then, the particles are counted after the drying process, and the evaluation is A when the number of particles increased compared to before the drying process is less than a preset threshold value, and the evaluation is B when it is greater than the threshold value.

[0143] In the first method, the circulation time was set to 0 seconds, 100 seconds, 400 seconds, 500 seconds, and 600 seconds, and in the second method, the number of repetitions of pressure increase and pressure decrease was set to 0, 2, 3, 4, and 5. Five evaluations were performed continuously under each condition (circulation time, number of repetitions). The number of evaluations A and B at each circulation time in the first method are shown in Table 1, and the number of evaluations A and B at each number of repetitions in the second method are shown in Table 2.

[0144]

Table 1

[0145]

[0146]

Table 2

[0147]

[0148] In this experiment, in the first method, the circulation time is set to more than 500 seconds, so that the increase in the number of particles in the entire drying process can be less than the threshold. In addition, in the second method, the pressure increase and pressure reduction are repeated more than three times, so that the increase in the number of particles in the entire drying process can be less than the threshold. In the first method, it is necessary to increase the pressure before circulation and to reduce the pressure after circulation. In addition, the total processing time in the case of repeating the pressure increase and pressure reduction three times in the second method is about 57% of the total processing time obtained by adding the circulation time of 500 seconds in the first method to the pressure increase time and the pressure reduction time. In addition, the total consumption of CO2 in the case of repeating the pressure increase and pressure reduction three times in the second method for the treatment fluid (CO2) used for drying treatment is about 33% of the total consumption of CO2 obtained by adding the consumption of CO2 in the circulation time of 500 seconds in the first method to the consumption of CO2 during the pressure increase and pressure reduction.

[0149] Thus, according to the second method, the total processing time and total consumption of the processing fluid required to suppress the increase of particles can be significantly reduced compared to the first method. That is, according to the second method, it is possible to obtain a cleaning efficiency superior to that of the first method.

[0150] In addition, in each of the above-mentioned embodiments, the position of the fluid supply nozzle 341 is set to be, for example, directly below the center of the wafer W accommodated in the processing container 301, but it is not limited to this. It is preferred that the position of the fluid supply nozzle 341 is below the holding plate 316, that is, the position where the fluid supply nozzle 341 cannot be seen when the holding plate 316 on which the wafer W is placed is observed from directly above. In other words, it is preferred that the CO2 gas ejected from the fluid supply nozzle 341 collides with the lower surface of the holding plate 316 or the back surface (lower surface) of the wafer W.

[0151] However, if the position of the fluid supply nozzle 341 deviates significantly from directly below the center of the wafer W, the flow of the CO2 gas in the processing container 301 becomes uneven, and the flow of the CO2 gas may go around the surface of the wafer W. Therefore, it is desirable that the fluid supply nozzle 341 is disposed at a position close to directly below the center of the wafer W. In addition, from the viewpoint of preventing or suppressing the flow of the CO2 gas from going around the surface of the wafer W, it is desirable that the fluid supply nozzle 341 ejects CO2 vertically upward or approximately vertically upward.

[0152] A holding step may be performed between the second pressure increasing step and the flow step. For example, after the pressure in the processing container 301 rises to the processing pressure (15 MPa), the flow step may not be performed immediately but the pressure in the processing container 301 may be maintained.

[0153] In the above-mentioned embodiments, the process is switched according to the change in pressure in the processing container 301. However, the relationship between the elapsed time of the process and the change in pressure in the processing container 301 may be obtained in advance, and the process may be switched according to the elapsed time. In this case, the change in pressure in the processing container 301 and the switching of the process are also substantially related.

[0154] Although preferred embodiments and the like have been described in detail above, the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions may be made to the above-described embodiments and the like without departing from the scope described in the claims.

[0155] For example, the processing fluid used in the drying process may be a fluid other than CO2 (e.g., a fluorine-based fluid), and any fluid that can remove the liquid used to prevent drying that fills the substrate in a supercritical state may be used as the processing fluid. In addition, the liquid used to prevent drying is not limited to IPA, and any liquid that can be used as a liquid to prevent drying may be used. The substrate to be processed is not limited to the semiconductor wafer W described above, and may also be other substrates such as a glass substrate for LCD, a ceramic substrate, etc.

Claims

1. A substrate processing device, which uses a processing fluid in a supercritical state to dry a substrate having liquid attached to the surface thereof, wherein: The substrate processing device comprises: a processing container for receiving the substrate; a substrate holding portion that holds the substrate horizontally in the processing container so that the surface faces upward; a fluid supplying part, which supplies a processing fluid into the processing container; a fluid discharge portion for discharging the processing fluid from the processing container; as well as a control unit that controls at least the operations of the fluid supply unit and the fluid discharge unit and the temperature of the substrate held by the substrate holding unit, The control unit performs the following steps by controlling the operations of the fluid supply unit and the fluid discharge unit: The process of supplying the processing fluid into the processing container containing the substrate with the liquid attached to the surface thereof to increase the pressure in the processing container to a processing pressure higher than the critical pressure of the processing fluid; and After the pressure in the processing container rises to the processing pressure, the processing fluid is supplied to the processing container while the pressure in the processing container is maintained at a pressure that allows the processing fluid to maintain a supercritical state, and the processing fluid is discharged from the processing container. The step of increasing the pressure in the processing container to the processing pressure includes the following steps: a step of increasing the pressure in the processing container to a first pressure that is higher than the critical pressure and lower than the processing pressure; and a step of increasing the pressure in the processing container from the first pressure to the processing pressure, The control unit controls the temperature of the substrate to a first temperature in the step of increasing the pressure in the processing container to the first pressure, The control unit controls the temperature of the substrate to a second temperature higher than the first temperature in the step of increasing the pressure in the processing container to the processing pressure. The first temperature is a temperature at which the liquid attached to the surface of the substrate is difficult to evaporate before being replaced by the processing fluid, and the second temperature is a temperature at which the liquid attached to the surface of the substrate is easily dissolved in the processing fluid.

2. The substrate processing apparatus according to claim 1, wherein: The fluid supply unit comprises: a first path for supplying the processing fluid into the processing container at a first temperature; as well as The second path supplies the processing fluid into the processing container at a second temperature higher than the first temperature.

3. The substrate processing apparatus according to claim 2, wherein: The substrate processing device comprises: a first vaporizer disposed in the first path and converting the processing fluid into a gas at the first temperature; and The second vaporizer is provided in the second path and converts the processing fluid into a gas at the second temperature.

4. The substrate processing apparatus according to claim 3, wherein: The fluid supply unit comprises: a first fluid supply unit for supplying the processing fluid into the processing container from below the substrate held by the substrate holding unit; as well as a second fluid supply unit for supplying the processing fluid into the processing container from a side of the substrate held by the substrate holding unit, The first fluid supply unit includes a portion of the second path and the first path, The second fluid supply portion includes another portion of the second path.

5. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The substrate processing apparatus includes a temperature control element, which is disposed on the substrate holding portion and is controlled by the control portion.

6. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The fluid supply unit includes a supply pipeline for the treatment fluid and a heater provided on the supply pipeline. The control unit controls the temperature of the substrate by adjusting the temperature of the processing fluid supplied into the processing container through the control of the heater.

7. The substrate processing apparatus according to claim 5, wherein: The fluid supply unit includes a supply pipeline for the treatment fluid and a heater provided on the supply pipeline. The control unit controls the temperature of the substrate by adjusting the temperature of the processing fluid supplied into the processing container through the control of the heater.

8. A substrate processing method, wherein: The substrate processing method has the following steps: A step of placing the substrate with the liquid attached to the surface in a processing container; A step of supplying a processing fluid into the processing container containing the substrate having the liquid attached to the surface thereof, so as to increase the pressure in the processing container to a processing pressure higher than a critical pressure of the processing fluid; and After the pressure in the processing container rises to the processing pressure, the processing fluid is supplied to the processing container while the pressure in the processing container is maintained at a pressure that allows the processing fluid to maintain a supercritical state, and the processing fluid is discharged from the processing container. The step of increasing the pressure in the processing container to the processing pressure includes the following steps: a step of increasing the pressure in the processing container to a first pressure that is higher than the critical pressure and lower than the processing pressure; and a step of increasing the pressure in the processing container from the first pressure to the processing pressure, The step of increasing the pressure in the processing container to the first pressure includes the step of controlling the temperature of the substrate to a first temperature. The step of increasing the pressure in the processing container to the processing pressure includes the step of controlling the temperature of the substrate to a second temperature higher than the first temperature. The first temperature is a temperature at which the liquid attached to the surface of the substrate is difficult to evaporate before being replaced by the processing fluid, and the second temperature is a temperature at which the liquid attached to the surface of the substrate is easily dissolved in the processing fluid.

9. The substrate processing method according to claim 8, wherein: The step of controlling the temperature of the substrate to the first temperature includes the step of supplying the processing fluid into the processing container at the first temperature. The step of controlling the temperature of the substrate to the second temperature includes the step of supplying the processing fluid into the processing container at the second temperature.

10. The substrate processing method according to claim 9, wherein: The step of supplying the processing fluid into the processing container at the first temperature includes the step of supplying the processing fluid from a first vaporizer. The step of supplying the processing fluid into the processing container at the second temperature includes the step of supplying the processing fluid from a second vaporizer.

11. The substrate processing method according to any one of claims 8 to 10, wherein: The step of controlling the temperature of the substrate to the first temperature includes the step of controlling the output of a temperature control element provided on a substrate holding portion that holds the substrate horizontally in the processing container with the surface facing upward. The step of controlling the temperature of the substrate to the second temperature includes the step of controlling the output of the temperature control element.

12. The substrate processing method according to any one of claims 8 to 10, wherein: The step of controlling the temperature of the substrate to the first temperature includes the step of controlling the output of a heater provided in a supply line of the processing fluid. The step of controlling the temperature of the substrate to the second temperature includes the step of controlling the output of the heater.

13. The substrate processing method according to claim 11, wherein: The step of controlling the temperature of the substrate to the first temperature includes the step of controlling the output of a heater provided in a supply line of the processing fluid. The step of controlling the temperature of the substrate to the second temperature includes the step of controlling the output of the heater.

Images