Substrate processing device and substrate processing method

Abstract

To provide a substrate processing device and substrate processing method which suppress pattern collapse on wafers during drying using processing fluid in the supercritical state.SOLUTION: In a substrate processing device, a processing fluid supply unit 80 which supplies processing fluid in the supercritical state to a processing container (main body 31) includes: fluid supply lines 71, 72A one of which is connected to a processing fluid supply source 90 and the other of which is connected to the processing container; a cooling unit (condenser 65) which cools the processing fluid in the gaseous state to generate the processing fluid in the liquid state; a pump 67; a heating unit (heater 68) which heats the processing fluid in the liquid state to generate the processing fluid in the supercritical state; a first flow rate adjustment unit 250 which adjusts the supply flow rate of the processing fluid supplied to the processing container; a control unit which controls the first flow rate adjustment unit; a branching point 62A which is provided between the pump and the first flow rate adjustment unit; a connection point 61 which is provided on the upstream side of the cooling unit; a branch line 73 which connects the branching point and the connection point; and a second flow rate adjustment unit 150A which adjusts the flow rate of the processing fluid flowing in the branch line.SELECTED DRAWING: Figure 8

Description

[Technical field]

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

[0002] In the manufacturing process of a semiconductor device in which a laminated structure of integrated circuits is formed on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as a 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 come to be used to remove liquids and the like adhering to the surface of the wafer 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] JP 2018-81966 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a substrate processing apparatus and a substrate processing method capable of suppressing collapse of a pattern on a wafer during a drying process using a processing fluid in a supercritical state. [Means for solving the problem]

[0006] A substrate processing apparatus according to one aspect of the present disclosure includes a processing vessel having a processing space capable of accommodating a substrate whose surface is wetted with a liquid, and a processing fluid supply unit configured to supply a processing fluid in a supercritical state to the processing vessel toward the liquid, the processing fluid supply unit including a fluid supply line having one end connected to a fluid supply source and the other end connected to the processing vessel, a cooling unit interposed in the fluid supply line and configured to cool the processing fluid in a gaseous state to generate the processing fluid in a liquid state, a pump interposed in the fluid supply line and provided downstream of the cooling unit, a heating unit interposed in the fluid supply line and provided downstream of the pump, the heating unit interposed in the fluid supply line and provided downstream of the pump, the heating unit interposed in the fluid supply line and provided downstream of the pump, the cooling unit, a first flow rate adjustment unit that adjusts a supply flow rate of the processing fluid supplied to the processing vessel, and a control unit that controls the first flow rate adjustment unit, the fluid supply line having a branch point between the pump and the first flow rate adjustment unit, a connection point that is provided on the fluid supply line upstream of the cooling unit, a branch line that connects the branch point and the connection point, and a second flow rate adjustment unit that is interposed in the fluid supply line and adjusts a flow rate of the processing fluid flowing through the branch line, the second flow rate adjustment unit having a first throttle and a second throttle connected in parallel to each other and interposed in the fluid supply line, and a first on-off valve connected in series to the second throttle. Effect of the Invention

[0007] According to the present disclosure, it is possible to suppress the collapse of a pattern on a wafer during a drying process using a processing fluid in a supercritical state. [Brief description 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; [Diagram 2] 3A and 3B are diagrams illustrating an example of the configuration of a liquid processing unit. [Diagram 3] FIG. 2 is a schematic perspective view showing a configuration example of a drying unit. [Figure 4] FIG. 2 is a diagram illustrating a configuration example of a drying unit. [Diagram 5] FIG. 4 is a diagram illustrating a configuration example of a supply unit. [Figure 6] 4 is a diagram showing a configuration example of a second flow rate adjustment unit and its periphery. FIG. [Figure 7] FIG. 1 is a diagram (part 1) showing specific operations of a supply unit and a drying unit. [Figure 8] FIG. 2 is a second diagram showing the specific operations of the supply unit and the drying unit. [Figure 9] FIG. 3 is a diagram (part 3) showing specific operations of the supply unit and the drying unit. [Figure 10] FIG. 4 is a diagram (part 4) showing specific operations of the supply unit and the drying unit. [Figure 11] FIG. 5 is a fifth diagram showing the specific operation 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 showing the specific operation of the supply unit and the drying unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, with reference to the attached drawings, an embodiment of the substrate processing system and the processing fluid supply method disclosed in the present application will be described in detail. Note that the present disclosure is not limited to the following embodiments. It should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, and the like may differ from reality. Furthermore, there may be parts in which the dimensional relationship and ratio 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 relationship, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are defined, and the positive direction of the Z-axis is defined as the vertical 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. On the carrier placement section 11, a plurality of carriers C are placed, each of which accommodates a plurality of semiconductor wafers W (hereinafter, referred to as "wafers W") in a horizontal state.

[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 transfer 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 transport block 4 includes a transport area 15 and a transport device 16. The transport area 15 is, for example, a rectangular parallelepiped region extending along the arrangement direction (X-axis direction) of the loading / unloading stations 2 and the processing stations 3. The transport device 16 is disposed in the transport 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 unit 14 and the multiple processing blocks 5 using the wafer holding mechanism.

[0018] The multiple processing blocks 5 are disposed adjacent to the transfer area 15 on both sides of the transfer area 15. Specifically, the multiple processing blocks 5 are disposed 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 load / unload stations 2 and the 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 interface 14 by one transport device 16 arranged in the transport 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 forming process. Specifically, the drying unit 18 dries the wafer W by bringing the wafer W after the liquid film forming 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 load / unload 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 a supercritical drying process 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, the delivery area 182 is disposed closer to the liquid processing unit 17 than the processing area 181. That is, in each processing block 5, the liquid processing unit 17, the delivery area 182, and the processing area 181 are disposed in this order along the 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 vertically.

[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] The control unit 7 includes a microcomputer and various circuits having a CPU (Central Processing Unit), a ROM (Read Only Memory), a 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 the transport devices 13, 16, the liquid processing unit 17, the drying unit 18, the 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 a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[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 the substrate processing apparatus 1 configured as described above, first, the transfer device 13 in the loading / unloading station 2 takes out the wafer W from the carrier C placed on the carrier placement unit 11, and places the taken-out wafer W on the delivery unit 14. The wafer W placed on the delivery unit 14 is taken out of the delivery unit 14 by the transfer device 16 in the processing station 3, and is carried into the liquid processing unit 17.

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

[0035] The wafer W that has been dried by the drying unit 18 is carried out from 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 of 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, for example, as a single-wafer cleaning device 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 approximately horizontally by wafer holding mechanism 25 arranged in outer chamber 23 which forms the processing space, and wafer W is rotated by rotating wafer holding mechanism 25 around a vertical axis.

[0038] Then, the liquid processing unit 17 performs a cleaning process on the upper surface of the wafer W by inserting the nozzle arm 26 into the area above the rotating wafer W and supplying chemical liquid and rinsing liquid in a predetermined order from the chemical liquid nozzle 26a provided at the tip of the nozzle arm 26.

[0039] In liquid processing unit 17, a 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 rinsing liquid supplied from chemical liquid supply path 25a.

[0040] The cleaning process, for example, first removes particles and organic contaminants using an alkaline chemical solution called SC1 liquid (a mixture of ammonia and hydrogen peroxide), then performs a rinse cleaning using deionized water (hereinafter referred to as "DIW"), which is a rinse solution.

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

[0042] The various chemical solutions described above are received in the outer chamber 23 or the inner cup 24 disposed within the outer chamber 23, and are discharged from a drainage outlet 23a provided in the bottom of the outer chamber 23 or a drainage outlet 24a provided in the bottom of the inner cup 24. Furthermore, the atmosphere within the outer chamber 23 is exhausted from an 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, the liquid processing unit 17 supplies IPA (IsoPropyl Alcohol) (hereinafter also referred to as "IPA liquid") in a liquid state to the upper and lower surfaces of the wafer W while rotating the wafer holding mechanism 25. As a result, the DIW remaining on both sides of the wafer W is replaced with IPA. Thereafter, the liquid processing unit 17 gently stops the rotation of the 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 transport device 16 by a transfer mechanism (not shown) provided in the wafer holding mechanism 25, and is 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 transportation 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 for loading and unloading the wafer W. The holding plate 32 holds the wafer W to be processed in a horizontal direction. The lid member 33 supports the holding plate 32 and seals the opening 34 when the wafer W is loaded into the 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. Note that, 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] Further, 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. In addition, a plurality of supply ports formed in line 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. Furthermore, 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, a plurality of discharge ports formed next to the fluid discharge header 40 face upward.

[0054] The fluid supply headers 38, 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] As shown in Fig. 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 adjustment unit 250, and a heater 68 in this order from the upstream side (the supply unit 19 side).

[0056] The valve 211 is a valve that adjusts the flow of the processing fluid on and off. When open, the processing fluid is allowed to flow into the downstream second supply line 72, and when closed, the processing fluid is not allowed to flow into the downstream second supply line 72.

[0057] The first flow rate adjustment 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 can circulate the processing fluid with the adjusted pressure to the downstream second supply line 72. The orifice 221 is an example of a third orifice, and the orifice 222 is an example of a fourth orifice.

[0059] The valve 212 is a valve that adjusts the on / off state of the flow of the processing fluid, and in the open state, the processing fluid flows through the downstream second supply line 72, and in the closed state, the processing fluid does not flow through the downstream second supply line 72. The valve 212 is an example of a second opening / closing 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, that is, 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 in the open state, the process fluid is allowed to flow into the downstream discharge line 76, and when in the closed state, the process fluid is not allowed to flow into 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 a 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 for detecting the temperature of the processing fluid within the main body 31. The output of the temperature sensor 241 is transmitted to the control unit .

[0065] In the drying unit 18, the IPA liquid between the patterns formed on the wafer W is gradually dissolved in the supercritical fluid by contacting the supercritical fluid in a high pressure state (for example, 16 MPa), and the spaces between the patterns are gradually replaced by the supercritical fluid. Finally, the spaces between the patterns are filled only with the supercritical fluid.

[0066] Then, 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 smaller viscosity than a liquid (e.g., IPA liquid), has a higher ability to dissolve liquid, and has no interface between the supercritical fluid and a 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 suppress 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. A filter 64, a condenser 65, a tank 66, and a pump 67 are provided on the first supply line 71 in this order from the upstream side (the treatment fluid supply source 90 side). 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 with the filter 64, it is possible to suppress 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 processing fluid. As a result, the condenser 65 cools the gaseous processing fluid flowing through the first supply line 71 to generate a liquid processing 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 pumps 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 for adjusting the on / off state of the flow of the processing fluid, and when in an open state, the processing fluid is allowed to flow through the downstream second supply lines 72A to 72C, and when in a closed state, the processing fluid is not allowed to flow through the downstream second supply lines 72A to 72C.

[0076] A branch point 62A is provided on the second supply line 72A, a branch point 62B is provided on the second supply line 72B, and a branch point 62C is provided on the second supply line 72C. The branch point 62A is provided between the branch point 77A and the valve 115A, the branch point 62B is provided between the branch point 77B and the valve 115B, and the branch point 62C is provided between the branch point 77B and the valve 115C. The supply unit 19 has a first branch line 73A connected to the branch point 62A, a first branch line 73B connected to the branch point 62B, and a first branch line 73C connected to the 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. Note that 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 on the upstream side of the filter 64 at their respective independent connection points.

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

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

[0080] As shown in FIG. 6, the second flow control section 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 can circulate the processing fluid with the adjusted pressure to the downstream second supply line 72A. The orifice 120 is an example of a first throttle, and the orifices 121-123 are an example of a second throttle.

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

[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, and is cooled and liquefied by the condenser 65. 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 part of it 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. In addition, another part 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] Hereinafter, specific operations of the supply unit 19 and the drying unit 18A will be described 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 section 80 includes the supply unit 19, and the valve 211, the first flow rate adjustment section 250, and the 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. 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 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 an output from the pressure sensor 142A and adjusts the set pressure of the back pressure valve 131A so that the pressure of the process fluid flowing downstream of the orifice 120 of the second supply line 72A becomes a preset pressure (e.g., 19.0 MPa). In other words, the control unit 7 changes the amount of the process fluid flowing through the first branch line 73A to control the pressure of the process fluid at the branch point 62A.

[0090] In the standby process, the processing fluid is not supplied from the processing fluid supply source 90, and the processing fluid circulates in the supply unit 19. At this time, the valves 111 to 113 are opened, so that the processing fluid is less likely to stagnate in the second flow rate adjustment part 150A, and the generation of particles due to the 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 at a first flow rate into the main body 31, and then the pressure is further increased by supplying the processing fluid in a supercritical state at a second flow rate higher than the first flow rate into the main body 31. That is, a two-stage pressurization is performed.

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

[0093] A part of the processing fluid that reaches the branch point 62A passes through the valve 115A and is supplied to the drying unit 18A, and the other part flows from the branch point 62A to the first branch line 73A. The processing fluid guided to 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 passes through the filter 64 and the condenser 65 to return to the tank 66.

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

[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 in a supercritical state. Then, the processing fluid in the supercritical state is supplied to the main body 31 at a first flow rate. The pressure in the main body 31 to which the processing fluid in the supercritical state is supplied gradually increases from 0 MPa. In 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, so that the supply pressure of the processing fluid in the supercritical state to the main body 31 is constant.

[0096] During pressure increase at the first flow rate, the control unit 7 receives an 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 starts pressure increase at the second flow rate.

[0097] In the pressure increase at the second flow rate, first, the 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 the drying unit 18A reaches the heater 68 through not only the orifice 221 but also the orifice 222, and is heated by the heater 68 to be brought into a supercritical state. Therefore, the flow rate of the processing fluid in a supercritical state supplied to the 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. That is, 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. Since the pressure of the processing fluid at the branch point 62A gradually increases, the supply pressure of the processing fluid in a supercritical state to the main body 31 also gradually increases.

[0099] In the pressurization at the second flow rate, as the pressure of the processing fluid at the branch point 62A increases, the pressure difference between the upstream side and the downstream side of the orifice 120 decreases. Therefore, when the pressure of the processing 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 pressure difference between the upstream side and the downstream side of the orifice 120 decreases, the processing 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 process fluid at the branch point 62A reaches a higher preset pressure (e.g., 14.5 MPa), the control unit 7 also opens the 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 the orifice 120 becomes smaller, 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 13.0 MPa to 15.0 MPa.

[0101] When the pressure of the process fluid at the branch point 62A reaches a higher preset pressure (e.g., 17.0 MPa), the control unit 7 also opens the 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 the orifice 120 becomes smaller, 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 15.0 MPa to 16.0 MPa.

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

[0103] <Distribution Processing> After the pressure increase process, a flow process is performed. The flow process is a process for drying the liquid film of the IPA liquid on the wafer W transferred into the main body 31 by 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 reaches the branch point 62A via the four orifices 120 to 123.

[0104] A part of the processing fluid that reaches the branch point 62A passes through the valve 115A and is supplied to the drying unit 18A, and the other part flows from the branch point 62A to the first branch line 73A. The processing fluid guided to 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 passes through the filter 64 and the condenser 65 to return to the tank 66.

[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 for discharging the processing fluid from the main body 31. In 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 the 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, etc. are controlled in the same manner as when the processing fluid is supplied to the drying unit 18A.

[0109] In this way, the substrate processing apparatus 1 equipped with the first flow rate adjustment unit 250 can adjust the flow rate of the supercritical processing fluid supplied into the main body 31 during the pressure increase process. For example, the processing fluid can be supplied at a small first flow rate, and then at a large second flow rate. A fine pattern may be formed on the surface of the wafer W carried into the main body 31, and in this case, supplying the processing fluid at a large flow rate may cause the pattern to collapse. In response to this, by supplying the processing fluid at the first flow rate before supplying the processing fluid at the second flow rate, the collapse of the pattern can be suppressed while the processing fluid in the supercritical state spreads between the patterns, and the collapse of the pattern can be suppressed even when the processing fluid is supplied at the second flow rate. Furthermore, since the processing fluid can be supplied at the second flow rate larger than the first flow rate, the time required for pressure increase can be shortened by supplying the processing fluid at the second flow rate after the processing fluid in the supercritical state spreads 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 adjustment unit 250. This makes it easy 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] In addition, since the second flow rate adjusting parts 150A-150C are provided in the supply unit 19, 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, so that the pressure difference between the upstream side and the downstream side of the orifice 120 becomes large. Even in this case, in this embodiment, the circulation flow rate can be reduced by closing the valves 111-113, and the load on the pump 67 can be suppressed. In addition, when the pressure is increased at the second flow rate, the valves 111-113 can be appropriately opened according to the pressure difference between the upstream side and the downstream side of the orifice 120, so that the processing fluid can continue to flow through the first branch line 73A and the second branch line 74.

[0112] The trigger for the transition 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. For example, the trigger may be the elapsed time of pressure increase at the first flow rate.

[0113] Although the preferred embodiments have been described in detail above, 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 CO2 (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 a glass substrate for an LCD, a ceramic substrate, etc. [Explanation of symbols]

[0115] 1. Substrate Processing Equipment 6. Control device 7 Control section 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 Processing fluid supply source 120, 121, 122, 123, 221, 222 Orifice 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 includes: a fluid supply line connected to a fluid supply source at one end and to the processing vessel at the other end; a cooling unit that is interposed in the fluid supply line and that cools the processing fluid in a gaseous state to generate the processing fluid in a liquid state; a pump provided in the fluid supply line downstream of the cooling unit; 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 first flow rate adjusting unit that is interposed in the fluid supply line and is provided between the pump and the heating unit, and adjusts a supply flow rate of the processing fluid supplied to the processing vessel; A control unit that controls the first flow rate adjustment unit; having a branch point provided on the fluid supply line between the pump and the first flow rate adjustment unit; a connection point provided on the fluid supply line upstream of the cooling portion; A branch line connecting the branch point and the connection point; a second flow rate adjusting unit that is interposed in the fluid supply line and adjusts a flow rate of the processing fluid flowing through the branch line; having The second 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 has

2. 2 . The substrate processing apparatus of claim 1 , wherein the control unit sets the supply flow rate to a first flow rate to increase pressure in the processing vessel, and then sets the supply flow rate to a second flow rate higher than the first flow rate to further increase pressure in the processing vessel.

3. 3. The substrate processing apparatus of claim 2, 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.

4. The first 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 according to claim 1 , further comprising:

5. 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 section.

6. The substrate processing apparatus according to claim 1 , wherein the control unit controls the first opening / closing valve in response to a pressure difference between an upstream side and a downstream side of the first throttle.

7. The substrate processing apparatus according to claim 1 , wherein a plurality of sets of the second throttle and the first on-off valve are provided in the second flow rate adjusting section.

8. The processing vessel includes a plurality of the processing vessels, The fluid supply line includes: a first fluid supply line in which the cooling unit and the pump are interposed; a plurality of second fluid supply lines, each connected between the first fluid supply line and each of the plurality of processing vessels; having The substrate processing apparatus according to claim 1 , wherein the heating unit and the first flow rate adjusting unit are provided for each of a plurality of the second fluid supply lines.

9. A substrate processing method using a substrate processing apparatus, comprising: The substrate processing apparatus includes: 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 includes: a fluid supply line connected to a fluid supply source at one end and to the processing vessel at the other end; a cooling unit that is interposed in the fluid supply line and that cools the processing fluid in a gaseous state to generate the processing fluid in a liquid state; a pump provided in the fluid supply line downstream of the cooling unit; 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 first flow rate adjusting unit that is interposed in the fluid supply line and is provided between the pump and the heating unit, and adjusts a supply flow rate of the processing fluid supplied to the processing vessel; having a branch point provided on the fluid supply line between the pump and the first flow rate adjustment unit; a connection point provided on the fluid supply line upstream of the cooling portion; A branch line connecting the branch point and the connection point; a second flow rate adjusting unit that is interposed in the fluid supply line and adjusts a flow rate of the processing fluid flowing through the branch line; having The second 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; having controlling the first flow rate adjusting unit and the first on-off valve to set the supply flow rate to a first flow rate and increase a pressure in the processing chamber; thereafter, controlling the first flow rate adjusting unit and the first on-off valve to set the supply flow rate to a second flow rate higher than the first flow rate, thereby further increasing the pressure inside the processing vessel; The substrate processing method comprises:

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