Substrate processing apparatus

Abstract

To provide a substrate processing apparatus that suppresses pattern collapse of a wafer during drying using a processing fluid in a supercritical state.SOLUTION: A substrate processing apparatus includes: a processing container having a processing space capable of accommodating a substrate whose surface is wet with liquid; and a processing fluid supply part configured to supply a processing fluid in a supercritical state toward the liquid to the processing container. The processing fluid supply part includes: a fluid supply line connected at one side to a fluid supply source and at the other side to the processing container; a pump provided in the fluid supply line; a heating part interposed in the fluid supply line and provided downstream of the pump and configured to heat the processing fluid in a liquid state to generate the processing fluid in a supercritical state; a branch point provided on the fluid supply line between the pump and the heating part; a connection point provided upstream of the pump on the fluid supply line; a pressure sensor provided between the heating part and the branch point; a branch line connecting the branch point and the connection point; and a first back pressure valve interposed in the branch line.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] In the manufacturing process of semiconductor devices, which involves forming a laminated structure of integrated circuits on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as wafer), liquid processing such as chemical cleaning or wet etching is performed. In recent years, drying methods using a processing fluid in a supercritical state have been increasingly used to remove liquids and the like adhering to the wafer surface during such liquid processing.

[0003] Patent Document 1 discloses a substrate processing apparatus in which a fluid supply tank is connected to a processing vessel through a supply line. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-81966 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a substrate processing apparatus that can prevent a pattern on a wafer from collapsing during a drying process using a processing fluid in a supercritical state. [Means for solving the problem]

[0006] a pressure sensor provided between the heating unit and the branch point; a branch line connecting the branch point and the connection point; a first back pressure valve provided in the branch line; a pressure sensor provided between the heating unit and the branch point; a pressure sensor provided between the heating unit and the branch point; a pressure sensor provided between the heating unit and the branch point; a pressure sensor provided between the pressure sensor and the branch point; a pressure sensor provided between the pressure sensor and the branch point; a pressure sensor provided between the pressure sensor and the branch point; a pressure sensor provided between the pressure sensor and the branch point; [Effects of the Invention]

[0007] According to the present disclosure, it is possible to prevent the pattern on the wafer from collapsing during a drying process using a processing fluid in a supercritical state. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of the configuration of a substrate processing apparatus according to an embodiment; [Figure 2] FIG. 2 is a diagram illustrating a configuration example of a liquid processing unit. [Figure 3] FIG. 2 is a schematic perspective view showing an example of the configuration of a drying unit. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a drying unit. [Figure 5] FIG. 2 is a diagram illustrating an example of the configuration of a supply unit. [Figure 6] FIG. 4 is a diagram illustrating a configuration example of a second flow rate adjusting unit and its periphery. [Figure 7] FIG. 10 is a diagram (part 1) showing specific operations of the supply unit and the drying unit. [Figure 8] FIG. 10 is a diagram (part 2) showing specific operations of the supply unit and the drying unit. [Figure 9]FIG. 10 is a diagram (part 3) showing specific operations of the supply unit and the drying unit. [Figure 10] FIG. 10 is a fourth diagram showing specific operations of the supply unit and the drying unit. [Figure 11] FIG. 5 is a diagram (part 5) showing specific operations of the supply unit and the drying unit. [Figure 12] FIG. 6 is a diagram (part 6) showing specific operations of the supply unit and the drying unit. [Figure 13] FIG. 7 is a diagram (part 7) showing specific operations of the supply unit and the drying unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of a substrate processing system and a processing fluid supply method disclosed herein will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments described below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from the actual situation. Furthermore, the dimensional relationships and ratios may differ between the drawings.

[0010] <Configuration of the substrate processing apparatus> First, the configuration of a substrate processing apparatus 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a substrate processing apparatus 1 according to an embodiment. In the following, to clarify the positional relationships, mutually orthogonal X-axis, Y-axis, and Z-axis are defined, and the positive direction of the Z-axis is defined as the vertically upward direction.

[0011] 1, the substrate processing apparatus 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0012] The loading / unloading station 2 includes a carrier placement section 11 and a transport section 12. A plurality of carriers C are placed on the carrier placement section 11, each of which accommodates a plurality of semiconductor wafers W (hereinafter referred to as "wafers W") in a horizontal position.

[0013] The transport section 12 is provided adjacent to the carrier placement section 11. Inside the transport section 12, a transport device 13 and a delivery section 14 are arranged.

[0014] The transfer device 13 includes a wafer holding mechanism that holds the wafer W. The transfer device 13 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the carrier C and the delivery unit 14 using the wafer holding mechanism.

[0015] The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport block 4, a plurality of processing blocks 5, and a plurality of supply units 19.

[0016] The transfer block 4 includes a transfer area 15 and a transfer device 16. The transfer area 15 is, for example, a rectangular parallelepiped region extending along the arrangement direction (X-axis direction) of the loading / unloading station 2 and the processing station 3. The transfer device 16 is arranged in the transfer area 15.

[0017] The transfer device 16 includes a wafer holding mechanism that holds the wafer W. The transfer device 16 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the delivery section 14 and the plurality of processing blocks 5 using the wafer holding mechanism.

[0018] The processing blocks 5 are arranged adjacent to the transfer area 15 on both sides of the transfer area 15. Specifically, the processing blocks 5 are arranged on one side (positive Y-axis direction side) and the other side (negative Y-axis direction side) of the transfer area 15 in a direction (Y-axis direction) perpendicular to the arrangement direction (X-axis direction) of the loading / unloading stations 2 and processing stations 3.

[0019] Although not shown, the processing blocks 5 are arranged in multiple stages (for example, three stages) along the vertical direction. The wafers W are transported between the processing blocks 5 arranged in each stage and the delivery part 14 by one transfer device 16 arranged in the transfer block 4. The number of stages of the processing blocks 5 is not limited to three.

[0020] Each processing block 5 includes a liquid processing unit 17 and a drying unit 18. The drying unit 18 is an example of a substrate processing section.

[0021] Liquid processing unit 17 performs a cleaning process to clean the upper surface, which is the pattern formation surface, of wafer W. Liquid processing unit 17 also performs a liquid film forming process to form a liquid film on the upper surface of wafer W after the cleaning process. The configuration of liquid processing unit 17 will be described later.

[0022] The drying unit 18 performs a supercritical drying process on the wafer W after the liquid film formation process. Specifically, the drying unit 18 dries the wafer W by bringing the wafer W after the liquid film formation process into contact with a processing fluid in a supercritical state (hereinafter also referred to as a "supercritical fluid"). The configuration of the drying unit 18 will be described later.

[0023] Liquid processing unit 17 and drying unit 18 are arranged along transport area 15 (that is, along the X-axis direction). Liquid processing unit 17 is arranged closer to loading / unloading station 2 than drying unit 18.

[0024] Thus, each processing block 5 includes one liquid processing unit 17 and one drying unit 18. That is, the substrate processing apparatus 1 is provided with the same number of liquid processing units 17 and drying units 18.

[0025] The drying unit 18 also includes a processing area 181 where supercritical drying processing is performed, and a delivery area 182 where the wafer W is delivered between the transfer block 4 and the processing area 181. The processing area 181 and the delivery area 182 are arranged along the transfer area 15.

[0026] Specifically, delivery area 182 is arranged closer to liquid processing unit 17 than processing area 181. That is, in each processing block 5, liquid processing unit 17, delivery area 182, and processing area 181 are arranged in this order along transport area 15.

[0027] One supply unit 19 is arranged for three processing blocks 5. For example, one supply unit 19 is arranged for three processing blocks 5 stacked in the vertical direction.

[0028] The supply unit 19 supplies the processing fluid to the drying unit 18. Specifically, the supply unit 19 includes a group of supply devices including a flow meter, a flow regulator, a back pressure valve, a heater, etc., and a housing that houses the group of supply devices. In this embodiment, the supply unit 19 supplies CO2 as the processing fluid to the drying unit 18. The configuration of the supply unit 19 will be described later. One supply unit 19 can supply the processing fluid to three processing blocks 5.

[0029] 1, the substrate processing apparatus 1 includes a control device 6. The control device 6 is, for example, a computer, and includes a control unit 7 and a storage unit 8.

[0030] Control unit 7 includes a microcomputer and various circuits having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output ports, etc. The CPU of the microcomputer reads and executes programs stored in the ROM to realize control of conveying devices 13 and 16, liquid processing unit 17, drying unit 18, supply unit 19, etc.

[0031] Such a program may be stored in a computer-readable storage medium and installed from that storage medium into the storage unit 8 of the control device 6. Examples of computer-readable storage media include hard disks (HDs), flexible disks (FDs), compact disks (CDs), magnetic optical disks (MOs), and memory cards.

[0032] The storage unit 8 is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk.

[0033] In substrate processing apparatus 1 configured as described above, first, transfer device 13 in load / unload station 2 removes wafer W from carrier C placed on carrier placement unit 11 and places the removed wafer W on delivery unit 14. Wafer W placed on delivery unit 14 is then removed from delivery unit 14 by transfer device 16 in processing station 3 and carried into liquid processing unit 17.

[0034] The wafer W carried into liquid processing unit 17 is subjected to cleaning processing and liquid film forming processing by liquid processing unit 17, and then carried out from liquid processing unit 17 by transfer device 16. The wafer W carried out from liquid processing unit 17 is carried into drying unit 18 by transfer device 16, and is subjected to drying processing by drying unit 18.

[0035] The wafer W that has been dried by the drying unit 18 is carried out of the drying unit 18 by the transfer device 16 and placed on the delivery section 14. Then, the processed wafer W placed on the delivery section 14 is returned to the carrier C on the carrier placement section 11 by the transfer device 13.

[0036] <Configuration of liquid processing unit> Next, the configuration of liquid processing unit 17 will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the configuration of liquid processing unit 17. Liquid processing unit 17 is configured as, for example, a single-wafer cleaning apparatus that cleans wafers W one by one by spin cleaning.

[0037] As shown in FIG. 2, in liquid processing unit 17, wafer W is held substantially horizontally by wafer holding mechanism 25 disposed in outer chamber 23 that forms the processing space, and wafer W is rotated by rotating wafer holding mechanism 25 around a vertical axis.

[0038] The liquid processing unit 17 then moves the nozzle arm 26 to above the rotating wafer W and supplies chemical liquid and rinsing liquid in a predetermined order from the chemical liquid nozzle 26a provided at the tip of the nozzle arm 26, thereby cleaning the top surface of the wafer W.

[0039] In liquid processing unit 17, chemical liquid supply path 25a is also formed inside wafer holding mechanism 25. The lower surface of wafer W is also cleaned by the chemical liquid and rinse liquid supplied from chemical liquid supply path 25a.

[0040] The cleaning process begins with the removal of particles and organic contaminants using an alkaline chemical called SC1 liquid (a mixture of ammonia and hydrogen peroxide), followed by a rinse using deionized water (hereinafter referred to as "DIW").

[0041] Next, the native oxide film is removed using an acidic chemical solution, diluted hydrofluoric acid (hereinafter referred to as "DHF"), and then rinse cleaning is performed using DIW.

[0042] The various chemical solutions described above are received in the outer chamber 23 or the inner cup 24 placed in the outer chamber 23, and are discharged from the drainage outlet 23a provided in the bottom of the outer chamber 23 or the drainage outlet 24a provided in the bottom of the inner cup 24. Furthermore, the atmosphere inside the outer chamber 23 is exhausted from the exhaust outlet 23b provided in the bottom of the outer chamber 23.

[0043] The liquid film forming process is performed after the rinsing process in the cleaning process. Specifically, liquid processing unit 17 supplies liquid IPA (IsoPropyl Alcohol) (hereinafter also referred to as "IPA liquid") to the upper and lower surfaces of wafer W while rotating wafer holding mechanism 25. This replaces the DIW remaining on both surfaces of wafer W with IPA. Thereafter, liquid processing unit 17 gently stops the rotation of wafer holding mechanism 25.

[0044] After the liquid film formation process, the wafer W, with the IPA liquid film formed on its upper surface, is transferred to the transfer device 16 by a transfer mechanism (not shown) provided in the wafer holding mechanism 25, and is then transported out of the liquid processing unit 17.

[0045] The liquid film formed on the wafer W prevents pattern collapse caused by evaporation (vaporization) of the liquid on the top surface of the wafer W during transport of the wafer W from the liquid processing unit 17 to the drying unit 18 or during loading into the drying unit 18.

[0046] <Drying unit configuration> Next, the configuration of the drying unit 18 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a schematic perspective view showing an example of the configuration of the drying unit 18. Fig. 4 is a view showing an example of the configuration of the drying unit 18.

[0047] 3, the drying unit 18 has a main body 31, a holding plate 32, and a lid member 33. The housing-like main body 31 has an opening 34 formed therein for loading and unloading the wafer W. The holding plate 32 holds the wafer W to be processed in a horizontal direction. The lid member 33 supports the holding plate 32 and also seals the opening 34 when the wafer W is loaded into the main body 31. The main body 31 is an example of a processing container.

[0048] The main body 31 is a container having a processing space formed therein capable of accommodating a wafer W having a diameter of, for example, 300 mm, and has a wall provided with supply ports 35, 36 and a discharge port 37. The supply ports 35, 36 and the discharge port 37 are connected to a supply flow path and a discharge flow path, respectively, for circulating a supercritical fluid to the drying unit 18.

[0049] Supply port 35 is connected to the side surface of housing-like main body 31 opposite opening 34. Supply port 36 is connected to the bottom surface of main body 31. Discharge port 37 is connected to the lower side of opening 34. Although two supply ports 35, 36 and one discharge port 37 are illustrated in FIG. 3, the numbers of supply ports 35, 36 and discharge ports 37 are not particularly limited.

[0050] Furthermore, fluid supply headers 38, 39 and a fluid discharge header 40 are provided inside the main body 31. The fluid supply headers 38, 39 are formed with a plurality of supply ports aligned in the longitudinal direction of the fluid supply headers 38, 39, and the fluid discharge header 40 is formed with a plurality of discharge ports aligned in the longitudinal direction of the fluid discharge header 40.

[0051] The fluid supply header 38 is connected to the supply port 35 and is provided adjacent to the side surface opposite the opening 34 inside the housing-like main body 31. The plurality of supply ports formed side by side on the fluid supply header 38 face the opening 34 side.

[0052] The fluid supply header 39 is connected to the supply port 36 and is provided at the center of the bottom surface inside the housing-like main body 31. A plurality of supply ports formed side by side on the fluid supply header 39 face upward.

[0053] The fluid discharge header 40 is connected to the discharge port 37 and is provided inside the housing-like main body 31 adjacent to the side surface on the opening 34 side and below the opening 34. In addition, the multiple discharge ports formed next to the fluid discharge header 40 face upward.

[0054] The fluid supply headers 38 and 39 supply the supercritical fluid into the main body 31. The fluid discharge header 40 guides the supercritical fluid in the main body 31 to the outside of the main body 31 and discharges it. The supercritical fluid discharged to the outside of the main body 31 via the fluid discharge header 40 includes IPA liquid that has been dissolved in the supercritical fluid in a supercritical state from the surface of the wafer W.

[0055] 4, a second supply line 72 of the supply unit 19 is connected to the drying unit 18. The second supply line 72 branches into two supply lines within the drying unit 18 (not shown in FIG. 4), one of which is connected to the supply port 35 and the other to the supply port 36 (not shown in FIG. 4). The second supply line 72 is provided with a valve 211, a first flow rate adjuster 250, and a heater 68, in this order from the upstream side (the supply unit 19 side).

[0056] Valve 211 is a valve that adjusts the flow of processing fluid on and off, and when open, it allows processing fluid to flow into the downstream second supply line 72, and when closed, it does not allow processing fluid to flow into the downstream second supply line 72.

[0057] The first flow rate adjusting unit 250 has an orifice 221, an orifice 222 connected in parallel to the orifice 221, and a valve 212 connected in series to the orifice 222, and adjusts the supply flow rate of the processing fluid supplied to the main body 31.

[0058] The orifices 221 and 222 serve to adjust the pressure by reducing the flow rate of the gaseous or liquid processing fluid supplied from the supply unit 19 through the valve 211. The orifices 221 and 222 allow the processing fluid with adjusted pressure to flow into the downstream second supply line 72. The orifice 221 is an example of a first orifice, and the orifice 222 is an example of a second orifice.

[0059] The valve 212 is a valve that adjusts the on / off state of the flow of the processing fluid, and when open, allows the processing fluid to flow into the downstream second supply line 72, and when closed, does not allow the processing fluid to flow into the downstream second supply line 72. The valve 212 is an example of a first on-off valve.

[0060] The heater 68 is, for example, a spiral heater. The heater 68 is wound around the second supply line 72 and heats the gaseous or liquid processing fluid flowing through the second supply line 72 to generate a supercritical processing fluid. The heater 68 is an example of a heating unit.

[0061] A discharge line 76 is connected to the discharge port 37. A pressure sensor 242, a valve 213, a flow meter 251, and a back pressure valve 231 are provided on the discharge line 76 in this order from the upstream side, i.e., from the main body 31 side.

[0062] The pressure sensor 242 measures the pressure of the process fluid flowing through the discharge line 76 immediately after the main body 31. That is, the pressure sensor 242 can measure the pressure of the process fluid inside the main body 31. The valve 213 is a valve that adjusts the flow of the process fluid on and off, and when open, allows the process fluid to flow through the downstream discharge line 76, and when closed, does not allow the process fluid to flow through the downstream discharge line 76. The flow meter 251 measures the flow rate of the process fluid flowing through the discharge line 76.

[0063] When the primary pressure of the discharge line 76 exceeds the set pressure, the back pressure valve 231 adjusts the valve opening to allow the fluid to flow to the secondary side, thereby maintaining the primary pressure at the set pressure. For example, the set pressure of the back pressure valve 231 is adjusted by the control unit 7 based on the output of the flow meter 251.

[0064] Furthermore, a temperature sensor 241 is provided to detect the temperature of the processing fluid inside the main body 31. The output of the temperature sensor 241 is sent to the control unit .

[0065] In the drying unit 18, the IPA liquid between the patterns formed on the wafer W comes into contact with the supercritical fluid under high pressure (for example, 16 MPa), and gradually dissolves in the supercritical fluid, gradually replacing the spaces between the patterns. Finally, the spaces between the patterns are filled only with the supercritical fluid.

[0066] After the IPA liquid is removed from between the patterns, the pressure inside the main body 31 is reduced from a high pressure state to atmospheric pressure, whereby the CO2 changes from a supercritical state to a gaseous state, and the spaces between the patterns are occupied only by gas. In this way, the IPA liquid between the patterns is removed, and the drying process of the wafer W is completed.

[0067] Here, the supercritical fluid has a lower viscosity than a liquid (e.g., IPA liquid) and a high ability to dissolve the liquid. In addition, there is no interface between the supercritical fluid and the liquid or gas in equilibrium. As a result, in a drying process using a supercritical fluid, the liquid can be dried without being affected by surface tension. Therefore, according to the embodiment, it is possible to prevent the pattern from collapsing during the drying process.

[0068] In the embodiment, an example is shown in which IPA liquid is used as the liquid for preventing drying and CO2 in a supercritical state is used as the processing fluid, but a liquid other than IPA may be used as the liquid for preventing drying, and a fluid other than CO2 in a supercritical state may be used as the processing fluid. The second supply line 72 constitutes a part of the second fluid supply line.

[0069] <Supply unit configuration> Next, the configuration of the supply unit 19 will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the configuration of the supply unit 19. The supply unit 19 shown in Fig. 5 supplies a processing fluid to three drying units 18A, 18B, and 18C. The drying units 18A to 18C correspond to the drying unit 18 in Fig. 4.

[0070] The supply unit 19 has a first supply line 71 connected to a processing fluid supply source 90 and a plurality of second supply lines 72A, 72B, and 72C connected to the first supply line 71. The second supply lines 72A, 72B, and 72C are connected to the first supply line 71 at a plurality of branch points 77A and 77B provided on the first supply line 71. Specifically, the second supply line 72A is connected to the first supply line 71 at the branch point 77A, and the second supply lines 72B and 72C are connected to the first supply line 71 at the branch point 77B. The second supply lines 72A to 72C correspond to the second supply line 72 in FIG. 4. The second supply line 72A is connected to the drying unit 18A, the second supply line 72B is connected to the drying unit 18B, and the second supply line 72C is connected to the drying unit 18C. The processing fluid supply source 90 is an example of a fluid supply source, the first supply line 71 is an example of a first fluid supply line, and the second supply lines 72A to 72C constitute a part of a second fluid supply line.

[0071] A connection point 61 is provided on the first supply line 71. The first supply line 71 is provided with, in this order from the upstream side (the treatment fluid supply source 90 side), a filter 64, a condenser 65, a tank 66, and a pump 67. The connection point 61 is provided upstream of the filter 64.

[0072] The filter 64 filters the gaseous processing fluid flowing through the first supply line 71 to remove foreign matter contained in the processing fluid. By removing foreign matter from the processing fluid using the filter 64, it is possible to suppress the generation of particles on the surface of the wafer W during the drying process of the wafer W using the supercritical fluid.

[0073] The condenser 65 is connected to, for example, a cooling water supply unit (not shown) and can exchange heat between the cooling water and the gaseous treatment fluid. As a result, the condenser 65 cools the gaseous treatment fluid flowing through the first supply line 71 to generate a liquid treatment fluid. The condenser 65 is an example of a cooling unit.

[0074] The tank 66 stores the liquid treatment fluid produced in the condenser 65. The pump 67 sends the liquid treatment fluid stored in the tank 66 to the downstream side of the first supply line 71.

[0075] In the supply unit 19, a valve 115A is provided on the second supply line 72A, a valve 115B is provided on the second supply line 72B, and a valve 115C is provided on the second supply line 72C. The valves 115A to 115C are valves that adjust the on / off state of the flow of the processing fluid, and when open, allow the processing fluid to flow through the downstream second supply lines 72A to 72C, and when closed, do not allow the processing fluid to flow through the downstream second supply lines 72A to 72C.

[0076] A branch point 62A is provided on second supply line 72A, a branch point 62B is provided on second supply line 72B, and a branch point 62C is provided on second supply line 72C. Branch point 62A is provided between branch point 77A and valve 115A, branch point 62B is provided between branch point 77B and valve 115B, and branch point 62C is provided between branch point 77B and valve 115C. Supply unit 19 has a first branch line 73A connected to branch point 62A, a first branch line 73B connected to branch point 62B, and a first branch line 73C connected to branch point 62C.

[0077] The supply unit 19 further includes a second branch line 74 connected to the first branch lines 73A to 73C. The first branch lines 73A to 73C are connected to the second branch line 74 at a plurality of connection points 75A and 75B provided on the second branch line 74. Specifically, the first branch line 73A is connected to the second branch line 74 at the connection point 75A, and the first branch lines 73B and 73C are connected to the second branch line 74 at the connection point 75B. The second branch line 74 is connected to the connection point 61. That is, the second branch line 74 connects the first branch lines 73A to 73C and the connection point 61. Alternatively, the second branch line 74 may not be provided, and the first branch lines 73A to 73C may be directly connected to the first supply line 71 upstream of the filter 64 at independent connection points.

[0078] In the second supply line 72A, a pressure sensor 141A and a second flow rate adjuster 150A are provided between the branch points 77A and 62A, in that order from the upstream side (the branch point 77A side). In the second supply line 72B, a pressure sensor 141B and a second flow rate adjuster 150B are provided between the branch points 77B and 62B, in that order from the upstream side (the branch point 77B side). In the second supply line 72C, a pressure sensor 141C and a second flow rate adjuster 150C are provided between the branch points 77B and 62C, in that order from the upstream side (the branch point 77B side). The second flow rate adjuster 150A adjusts the flow rate of the processing fluid flowing through the first branch line 73A, the second flow rate adjuster 150B adjusts the flow rate of the processing fluid flowing through the first branch line 73B, and the second flow rate adjuster 150C adjusts the flow rate of the processing fluid flowing through the first branch line 73C.

[0079] Here, the configuration of the second flow rate adjustment units 150A to 150C will be described. Fig. 6 is a diagram showing an example of the configuration of the second flow rate adjustment unit 150A and its surroundings.

[0080] As shown in FIG. 6, the second flow rate control unit 150A has an orifice 120, orifices 121, 122, and 123 connected in parallel to the orifice 120, a valve 111 connected in series to the orifice 121, a valve 112 connected in series to the orifice 122, and a valve 113 connected in series to the orifice 123.

[0081] The orifices 120-123 serve to reduce the flow rate of the processing fluid flowing through the second supply line 72A and adjust the pressure. The orifices 120-123 allow the processing fluid with adjusted pressure to flow through the downstream second supply line 72A. The orifice 120 is an example of a third orifice, and the orifices 121-123 are examples of a fourth orifice.

[0082] The valves 111 to 113 are valves that adjust the flow of the processing fluid on and off, and when open, allow the processing fluid to flow into the downstream second supply line 72A, and when closed, do not allow the processing fluid to flow into the downstream second supply line 72A. The valves 111 to 113 are an example of second on-off valves.

[0083] The second flow rate adjustment units 150B and 150C have the same configuration as the second flow rate adjustment unit 150A.

[0084] Here, the basic operation of the supply unit 19 will be described.

[0085] The gaseous process fluid supplied from the process fluid supply source 90 to the first supply line 71 is supplied to the condenser 65 via the filter 64, where it is cooled and liquefied. The liquefied process fluid is stored in the tank 66. The liquid process fluid stored in the tank 66 is made into a high-pressure fluid by the pump 67, and a portion of this is supplied to the drying units 18A to 18C. The high-pressure fluid supplied to the drying units 18A to 18C is made into a supercritical state by the heater 68 and used for drying. Another portion of the high-pressure fluid flows into the first branch lines 73A to 73C and returns to the first supply line 71 from the connection point 61. In this manner, the process fluid circulates within the supply unit 19.

[0086] <Specific operations of the supply unit and drying unit> Next, the specific operations of the supply unit 19 and the drying unit 18 will be described.

[0087] Specific operations of the supply unit 19 and the drying unit 18A will be described below based on a drying method (substrate processing method) performed using the drying unit 18A. FIGS. 7 to 13 are diagrams showing specific operations of the supply unit 19 and the drying unit 18A. As an example, FIGS. 7 to 13 show specific operations of the supply unit 19 when a processing fluid is supplied to the drying unit 18A. During the operations shown in FIGS. 7 to 13, the pump 67 continues to operate. As shown in FIGS. 7 to 13, the processing fluid supply unit 80 includes the supply unit 19, and the valve 211, first flow rate adjuster 250, and heater 68 in the drying unit 18.

[0088] <Waiting process> The standby process is a process of waiting for the supply of the processing fluid after the wafer W is transferred to the drying unit 18A. In the standby process, as shown in FIG. 7, the valves 111 to 113 are opened. Also, the valve 114A is opened, and the valve 115A is closed. The processing fluid introduced into the second supply line 72A passes through the orifice 120 and the orifices 121 to 123 to reach the branch point 62A and then flows into the first branch line 73A. The processing fluid introduced into the first branch line 73A passes through the back pressure valve 131A, the valve 114A, and the second branch line 74 to reach the connection point 61, and further returns to the tank 66 via the filter 64 and the condenser 65.

[0089] During this series of operations, the control unit 7 receives the output from the pressure sensor 142A and adjusts the set pressure of the backpressure valve 131A so that the pressure of the process fluid flowing downstream of the orifice 120 in the second supply line 72A becomes a preset pressure (e.g., 19.0 MPa). In other words, the control unit 7 controls the pressure of the process fluid at the branch point 62A by changing the amount of process fluid flowing through the first branch line 73A.

[0090] During standby processing, the processing fluid is not supplied from the processing fluid supply source 90, and the processing fluid circulates within the supply unit 19. At this time, the valves 111 to 113 are open, so the processing fluid is less likely to stagnate within the second flow rate control part 150A, and the generation of particles due to stagnation can be suppressed.

[0091] <Boost processing> After the standby process, a pressurization process is performed. The pressurization process is a process for increasing the pressure inside the main body 31. In the pressurization process, first, the pressure is increased by supplying the processing fluid in a supercritical state into the main body 31 at a first flow rate, and then the pressure is further increased by supplying the processing fluid in a supercritical state into the main body 31 at a second flow rate higher than the first flow rate. In other words, a two-stage pressurization is performed.

[0092] 8, when the pressure is increased at the first flow rate, the valves 111 to 113 are closed. The valves 114A and 115A are opened. The processing fluid introduced into the second supply line 72A passes through the single orifice 120 and reaches the branch point 62A without passing through the three orifices 121 to 123.

[0093] A portion of the processing fluid that reaches branch point 62A passes through valve 115A and is supplied to drying unit 18A, and another portion flows from branch point 62A to first branch line 73A. The processing fluid that has been guided to first branch line 73A passes through back pressure valve 131A, valve 114A, and second branch line 74 to reach connection point 61, and then returns to tank 66 via filter 64 and condenser 65.

[0094] During this series of operations, the control unit 7 receives the output from the pressure sensor 142A and adjusts the set pressure of the backpressure valve 131A so that the pressure of the process fluid flowing downstream of the orifice 120 in the second supply line 72A becomes a preset pressure (e.g., 7.0 MPa). In other words, the control unit 7 controls the pressure of the process fluid at the branch point 62A by changing the amount of process fluid flowing through the first branch line 73A.

[0095] In addition, in the drying unit 18A, the valve 211 is opened, and the valves 212 and 213 are closed. Therefore, the processing fluid supplied to the drying unit 18 reaches the heater 68 via the orifice 221 without passing through the orifice 222, and is heated by the heater 68 to be brought into a supercritical state. The processing fluid in the supercritical state is then supplied to the main body 31 at a first flow rate. The pressure inside the main body 31 to which the processing fluid in the supercritical state has been supplied gradually increases from 0 MPa. During the pressure increase at the first flow rate, the pressure of the processing fluid at the branch point 62A is maintained at a preset pressure, and therefore the supply pressure of the processing fluid in the supercritical state to the main body 31 is constant.

[0096] While the pressure is being increased at the first flow rate, the control unit 7 receives the output from the pressure sensor 242, and when the pressure inside the main body 31 reaches a preset pressure (for example, 5.0 MPa), the control unit 7 shifts to increasing the pressure at the second flow rate.

[0097] In the pressure increase at the second flow rate, first, valve 212 is opened as shown in Fig. 9. The states of the other valves are the same as those shown in Fig. 8. As a result, the processing fluid supplied to drying unit 18A passes through not only orifice 221 but also orifice 222 and reaches heater 68, where it is heated by heater 68 and brought to a supercritical state. Therefore, the flow rate of the processing fluid in a supercritical state supplied to main body 31 increases to the second flow rate.

[0098] During this series of operations, the control unit 7 receives the output from the pressure sensor 242 and adjusts the set pressure of the back pressure valve 131A so that the pressure inside the main body 31 gradually increases at a predetermined rate. In other words, the control unit 7 controls the pressure of the processing fluid at the branch point 62A by changing the amount of processing fluid flowing through the first branch line 73A. Because the pressure of the processing fluid at the branch point 62A gradually increases, the supply pressure of the supercritical processing fluid to the main body 31 also gradually increases.

[0099] During pressure increase at the second flow rate, as the pressure of the process fluid at the branch point 62A increases, the differential pressure between the upstream and downstream sides of the orifice 120 decreases. Therefore, when the pressure of the process fluid at the branch point 62A reaches a preset pressure (e.g., 11.0 MPa), the control unit 7 opens the valve 111 as shown in FIG. 10 . The states of the other valves are the same as those shown in FIG. 9 . As a result, even if the differential pressure between the upstream and downstream sides of the orifice 120 decreases, the process fluid can continue to flow through the first branch line 73A and the second branch line 74. During this period, the pressure inside the main body 31 increases, for example, from 5.0 MPa to 13.0 MPa.

[0100] When the pressure of the processing fluid at branch point 62A reaches a higher preset pressure (e.g., 14.5 MPa), control unit 7 also opens valve 112, as shown in Fig. 11. The states of the other valves are the same as those shown in Fig. 10. As a result, even if the pressure difference between the upstream and downstream sides of orifice 120 becomes smaller, processing fluid can continue to flow through first branch line 73A and second branch line 74. During this period, the pressure inside main body 31 increases, for example, from 13.0 MPa to 15.0 MPa.

[0101] When the pressure of the processing fluid at branch point 62A reaches a higher preset pressure (e.g., 17.0 MPa), control unit 7 also opens valve 113, as shown in Fig. 12. The states of the other valves are the same as those shown in Fig. 11. As a result, even if the pressure difference between the upstream and downstream sides of orifice 120 becomes smaller, processing fluid can continue to flow through first branch line 73A and second branch line 74. During this period, the pressure inside main body 31 increases, for example, from 15.0 MPa to 16.0 MPa.

[0102] In this way, the voltage boosting process is carried out.

[0103] <Distribution processing> After the pressure increase process, a flow process is performed. The flow process is a process in which the liquid film of IPA on the wafer W being transferred into the main body 31 is dried using a processing fluid in a supercritical state. In the flow process, as shown in FIG. 13, the valves 111 to 113 are opened. Also, the valves 114A and 115A are opened. The processing fluid introduced into the second supply line 72A passes through four orifices 120 to 123 and reaches the branch point 62A.

[0104] A portion of the processing fluid that reaches branch point 62A passes through valve 115A and is supplied to drying unit 18A, and another portion flows from branch point 62A to first branch line 73A. The processing fluid that has been guided to first branch line 73A passes through back pressure valve 131A, valve 114A, and second branch line 74 to reach connection point 61, and then returns to tank 66 via filter 64 and condenser 65.

[0105] In addition, in the drying unit 18A, the valves 211 to 213 are opened. Therefore, the processing fluid flows into the second supply line 72A and is supplied into the main body 31 from the supply port 35. The processing fluid also flows through the discharge line 76 from the discharge port 37 of the main body 31 and is discharged to the outside through the valve 213, the flow meter 251, and the back pressure valve 231.

[0106] During this series of operations, the control unit 7 receives the output from the pressure sensor 242 and adjusts the set pressure of the back pressure valve 131A so that the pressure inside the main body 31 is maintained at the set pressure during circulation treatment. The control unit 7 also receives the output from the flow meter 251 and adjusts the set pressure of the back pressure valve 231 so that the flow rate of the treatment fluid flowing through the discharge line 76 becomes a predetermined flow rate.

[0107] <Discharge processing> After the flow process, a discharge process is performed. The discharge process is a process of discharging the processing fluid from the main body 31. During the discharge process, the valves 115A and 211 are closed. The states of the other valves are the same as those shown in FIG. 13. When the pressure inside the main body 31 becomes lower than the critical pressure of the processing fluid due to the discharge process, the processing fluid in a supercritical state vaporizes and leaves the recesses of the pattern. This completes the drying process for one wafer W.

[0108] When the processing fluid is supplied to the drying units 18B and 18C, the valves 111 to 113 and 212 are controlled in the same manner as when the processing fluid is supplied to the drying unit 18A.

[0109] In this manner, the substrate processing apparatus 1 equipped with the first flow rate adjuster 250 can adjust the flow rate of the supercritical processing fluid supplied into the main body 31 during the pressurization process. For example, the processing fluid can be supplied at a small first flow rate and then at a large second flow rate. The surface of the wafer W loaded into the main body 31 may have a fine pattern formed thereon. In such a case, supplying the processing fluid at a large flow rate may cause the pattern to collapse. In response to this, supplying the processing fluid at the first flow rate before supplying the processing fluid at the second flow rate can spread the supercritical processing fluid between the patterns while suppressing pattern collapse, thereby suppressing pattern collapse even when the processing fluid is supplied at the second flow rate. Furthermore, since the processing fluid can be supplied at a second flow rate greater than the first flow rate, the time required for pressurization can be shortened by supplying the processing fluid at the second flow rate after the supercritical processing fluid has spread between the patterns.

[0110] Furthermore, in the substrate processing apparatus 1, the heater 68 is provided downstream (toward the main body 31) of the first flow rate adjuster 250. This makes it easier to stabilize the temperature of the processing fluid in a supercritical state when it is supplied into the main body 31. In particular, excellent temperature uniformity can be obtained among the multiple drying units 18A to 18C.

[0111] Furthermore, since the supply unit 19 is provided with the second flow rate adjusters 150A-150C, the flow rate (circulation flow rate) of the processing fluid circulating through the first branch lines 73A-73C can be stabilized. For example, when the pressure is increased at the first flow rate, the pressure inside the main body 31 is low, and the pressure of the processing fluid at the branch point 62A is also low, resulting in a large pressure difference between the upstream and downstream sides of the orifice 120. Even in this case, in this embodiment, the circulation flow rate can be reduced by closing the valves 111-113, thereby reducing the load on the pump 67. Furthermore, when the pressure is increased at the second flow rate, the processing fluid can continue to flow through the first branch line 73A and the second branch line 74 by appropriately opening the valves 111-113 depending on the pressure difference between the upstream and downstream sides of the orifice 120.

[0112] The trigger for transitioning from pressure increase at the first flow rate to pressure increase at the second flow rate is not limited to the output of the pressure sensor 242, and may be, for example, the elapsed time since pressure increase at the first flow rate.

[0113] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0114] For example, the processing fluid used in the drying process may be a fluid other than CO (e.g., a fluorine-based fluid), and any fluid capable of removing the anti-drying liquid piled on the substrate in a supercritical state may be used as the processing fluid. The anti-drying liquid is also not limited to IPA, and any liquid usable as an anti-drying liquid may be used. The substrate to be processed is not limited to the semiconductor wafer W described above, and may be other substrates such as LCD glass substrates and ceramic substrates. [Explanation of symbols]

[0115] 1. Substrate processing equipment 6. Control device 7 Control Unit 8 Memory section 18, 18A, 18B, 18C Drying Unit 19 Supply Unit 31 Main Unit 61, 75A, 75B connection points 62A, 62B, 62C, 77A, 77B Junction 64 filters 65 capacitor 66 Tank 67 Pump 68 Heater 71 First Supply Line 72, 72A, 72B, 72C Second supply line 73A, 73B, 73C First branch line 74 Second Branch Line 80 Processing fluid supply unit 90 Treatment fluid supply source 120, 121, 122, 123, 221, 222 Orifices 131A, 131B, 131C, 231 Back pressure valve 141A, 141B, 141C, 142A, 142B, 142C, 242 Pressure Sensors 150A, 150B, 150C 2nd flow adjustment section 250 1st flow rate adjustment section 251 Flow meter W wafer

Claims

1. a processing vessel having a processing space capable of accommodating a substrate whose surface is wetted with a liquid; a processing fluid supply unit that supplies a processing fluid in a supercritical state toward the liquid to the processing vessel; Equipped with The processing fluid supply unit a fluid supply line connected to a fluid supply source at one end and to the processing vessel at the other end; a pump provided in the fluid supply line; a heating unit that is interposed in the fluid supply line and provided downstream of the pump, and that heats the processing fluid in a liquid state to generate the processing fluid in a supercritical state; a branch point provided on the fluid supply line between the pump and the heating unit; a connection point provided on the fluid supply line upstream of the pump; a pressure sensor provided between the heating unit and the branch point; a branch line connecting the branch point and the connection point; a first back pressure valve interposed in the branch line; The substrate processing apparatus has:

2. The substrate processing apparatus according to claim 1 , further comprising a control unit that adjusts the pressure of the first back pressure valve based on an output from the pressure sensor.

3. a treatment fluid discharge part having a discharge line connected to the treatment vessel at one end and discharging the treatment fluid from the treatment vessel; the treatment fluid discharge unit has a flow meter and a second back pressure valve interposed in the discharge line; The substrate processing apparatus according to claim 2 , wherein the control unit adjusts the pressure of the second back pressure valve based on an output from the flow meter.

4. 4. The substrate processing apparatus of claim 2, wherein the control unit increases the pressure in the processing vessel by setting a supply flow rate of the processing fluid supplied to the processing vessel to a first flow rate, and then increases the pressure in the processing vessel by setting the supply flow rate to a second flow rate higher than the first flow rate.

5. 5. The substrate processing apparatus of claim 4, wherein the control unit sets the supply flow rate to the first flow rate until the pressure in the processing vessel reaches a first pressure, and sets the supply flow rate to the second flow rate when the pressure in the processing vessel reaches the first pressure.

6. The substrate processing apparatus according to claim 1 , wherein the processing fluid is in a gaseous state or a liquid state between the pump and the heating unit.

7. a first flow rate adjusting unit that is interposed in the fluid supply line and is provided between the pump and the heating unit, and that adjusts the supply flow rate of the processing fluid that is supplied to the processing vessel; The first flow rate adjustment unit is a first throttle and a second throttle connected in parallel to each other and disposed in the fluid supply line; a first on-off valve connected in series to the second throttle; The substrate processing apparatus according to claim 1 , further comprising:

8. The substrate processing apparatus according to claim 1 , further comprising a second flow rate adjusting unit disposed in the fluid supply line to adjust a flow rate of the processing fluid flowing through the branch line.

9. The second flow rate adjustment unit is a third throttle and a fourth throttle connected in parallel to each other and disposed in the fluid supply line; a second on-off valve connected in series to the fourth throttle; The substrate processing apparatus of claim 8 , further comprising:

10. a control unit that controls the first flow rate adjustment unit; a second flow rate adjusting unit that is interposed in the fluid supply line and adjusts the flow rate of the processing fluid flowing through the branch line; and The second flow rate adjustment unit is a third throttle and a fourth throttle connected in parallel to each other and disposed in the fluid supply line; a second on-off valve connected in series to the fourth throttle; and The substrate processing apparatus according to claim 7 , wherein the control unit controls the second opening / closing valve in accordance with a pressure difference between an upstream side and a downstream side of the third restrictor.

11. 11. The substrate processing apparatus according to claim 9, wherein a plurality of sets of the fourth throttle and the second on-off valve are provided in the second flow rate adjusting section.

12. The processing vessel has a plurality of the processing vessels, The fluid supply line a first fluid supply line in which the pump is interposed; a plurality of second fluid supply lines, each connected between the first fluid supply line and each of the plurality of processing vessels; and The substrate processing apparatus according to claim 1 , wherein the heating unit is provided for each of a plurality of the second fluid supply lines.

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