Substrate processing method, substrate processing apparatus, and storage medium

Abstract

The substrate processing method includes: a liquid film forming step of forming a liquid film of a protective liquid covering the surface of a substrate by supplying the protective liquid for protecting a pattern on the surface of the substrate to the surface of the substrate after a liquid processing step performed with a processing liquid; a substrate loading step in which, after the liquid film formation step, the substrate is loaded into the processing container in a state in which the liquid film of the protective liquid is formed; and a substrate drying step in which, after the substrate loading step, the pressurized processing fluid is supplied to the processing container to maintain the pressure in the processing container at a pressure at which the processing fluid is maintained in a supercritical state, and the pressurized processing fluid is supplied to the processing container to replace the processing fluid on the substrate with the processing fluid, thereby drying the substrate. And discharging the processing fluid from the processing container to dry the substrate. And a back surface cleaning step in which a cleaning liquid for cleaning the back surface of the substrate is supplied to the back surface of the substrate, the back surface cleaning step being performed at least during the period in which the liquid film forming step is performed.

Description

Technical Field

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

[0002] In the manufacturing process of a semiconductor device having a stacked structure of integrated circuits formed on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as a wafer), liquid treatment such as chemical cleaning or wet etching is performed. In recent years, a drying method using a processing fluid in a supercritical state has been used to remove liquid or the like attached to the surface of the wafer during such liquid treatment (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-101241 Summary of the invention

[0006] The present disclosure provides a technology capable of suppressing adhesion of particles to a substrate.

[0007] A substrate processing method according to an embodiment of the present disclosure includes: a liquid film forming process, supplying a protective liquid having a pattern for protecting the surface of the substrate to the surface of the substrate after a liquid processing process using a processing liquid is performed, so as to form a liquid film of the protective liquid covering the surface of the substrate; a substrate carrying-in process, after the liquid film forming process, carrying the substrate into a processing container in a state where the liquid film of the protective liquid is formed; a substrate drying process, after the substrate carrying-in process, supplying a pressurized processing fluid to the processing container to maintain the pressure in the processing container at a pressure that maintains the processing fluid in a supercritical state, supplying the pressurized processing fluid to the processing container to replace the processing liquid on the substrate with the processing fluid, and discharging the processing fluid from the processing container to dry the substrate; and a back side cleaning process, supplying a cleaning liquid to the back side of the substrate for cleaning the back side of the substrate, wherein the back side cleaning process is performed at least during the period of performing the liquid film forming process.

[0008] According to the above-described embodiment of the present disclosure, it is possible to suppress adhesion of particles to the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic cross-sectional view of a substrate processing system according to one embodiment of a substrate processing apparatus.

[0010] Figure 2 This is a schematic longitudinal cross-sectional view of a liquid processing unit included in the substrate processing system.

[0011] Figure 3 This is a schematic longitudinal cross-sectional view of a supercritical drying unit included in the substrate processing system.

[0012] Figure 4A-4L This is a schematic diagram for explaining a series of steps performed in the liquid processing unit.

[0013] Figure 5 This is a schematic diagram showing a state in which a processing liquid supplied to the surface of a substrate flows around to the back surface. DETAILED DESCRIPTION

[0014] Below, refer to Figure 1 The structure of a substrate processing system 1 according to an embodiment of a substrate processing apparatus will be briefly described. In order to simplify the description, an XYZ orthogonal coordinate system (see Figure 1 ) for appropriate reference.

[0015] <Overall Structure of Substrate Processing System>

[0016] like Figure 1 As shown, the substrate processing system 1 includes a loading and unloading station 2 and a processing station 3 .

[0017] The loading / unloading station 2 includes a load port 11 and a transfer block 12. A plurality of carriers C are placed on the load port 11. Each carrier C stores a plurality of substrates W (eg, semiconductor wafers) in a horizontal posture at intervals in the vertical direction.

[0018] A transport device 13 and a delivery unit 14 are provided in the transport block 12. The delivery unit 14 has an unprocessed substrate placement portion for temporarily placing one or more unprocessed substrates W (substrates W before being processed in the processing station 3), and a processed substrate placement portion for temporarily placing one or more processed substrates W (substrates W processed in the processing station 3). The transport device 13 can transport substrates W between the delivery unit 14 and any carrier C placed on the load port 11.

[0019] The processing station 3 includes a conveying block 4 and a pair of processing blocks 5 arranged on both sides of the conveying block 4 in the Y direction. A liquid processing unit 100, a supercritical drying unit 200, and a processing fluid supply cabinet 19 are provided in each processing block 5. In the present embodiment, the liquid processing unit 100 and the supercritical drying unit 200 are monolithic processing units. The processing fluid required for processing is supplied from the processing fluid supply cabinet 19 to the liquid processing unit 100 and the supercritical drying unit 200.

[0020] The transfer block 4 includes a transfer area 15 and a transfer device 16 disposed in the transfer area 15 . The transfer device 16 can transfer the substrate W between the delivery unit 14 , any liquid processing unit 100 , and any supercritical drying unit 200 .

[0021] Each processing block 5 may also have a multi-layer (e.g., three-layer) structure. In this case, one liquid processing unit 100, one supercritical drying unit 200, and one processing fluid supply cabinet 19 are provided on each layer. In this case, one transport device 16 may be able to access the liquid processing units 100 and supercritical drying units 200 on all layers.

[0022] The substrate processing system 1 includes a control device 6. The control device 6 is, for example, a computer, and includes a processing unit 61 and a storage unit 62. The processing unit 61 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, and various circuits. The CPU of the microcomputer reads and executes the program stored in the ROM to control the conveying devices 13, 16, the liquid processing unit 100, the supercritical drying unit 200, and the processing fluid supply cabinet 19. In addition, the program can also be recorded in a storage medium (non-transitory storage medium) that can be read by a computer, and installed from the storage medium to the storage unit 62 of the control device 6. As a storage medium that can be read by a computer, there are, for example, a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), a memory card, and the like. The storage unit 62 is implemented by, for example, a semiconductor memory element such as a RAM, a flash memory, or a storage device such as a hard disk or an optical disk.

[0023] Next, a brief description will be given of a conveyance flow of the substrate W in the above-mentioned substrate processing system 1 .

[0024] An external transfer robot (not shown) places a carrier C containing unprocessed substrates W on the load port 11. The transfer device 13 takes out a substrate W from the carrier C and carries it into the delivery unit 14. The transfer device 16 takes out a substrate W from the delivery unit 14 and carries it into the liquid processing unit 100.

[0025] Liquid processing consisting of a plurality of steps is performed in liquid processing unit 100. The details of the liquid processing will be described later. In the final step, an IPA (isopropyl alcohol) liquid film (also referred to as an IPA paddle) having a predetermined film thickness is formed on the surface of substrate W.

[0026] Next, the substrate W with the IPA liquid mass formed on the surface is taken out from the liquid processing unit 100 by the conveying device 16 and moved into the supercritical drying unit 200. In the supercritical drying unit 200, the substrate W is dried according to the process described later using the supercritical drying technology. In the supercritical drying technology, no surface tension that may cause the pattern to collapse is applied to the pattern, so it can be advantageously used to dry a substrate formed with a fine and high aspect ratio pattern. Afterwards, the conveying device 16 takes the dried substrate W out of the supercritical drying unit 200 and moves it into the delivery unit 14. The conveying device 13 takes the substrate W out of the delivery unit 14 and accommodates it in the original carrier C placed on the loading port 11. Through the above, a series of processing on a substrate is completed.

[0027] <Liquid Processing Unit>

[0028] Next, refer to Figure 2 Next, the structure of liquid processing unit 100 will be described.

[0029] The liquid processing unit 100 includes a chamber 120 , a substrate holding and rotating mechanism 130 , a first processing fluid supply unit 140 , a second processing fluid supply unit 150 , and a recovery cup 160 .

[0030] The chamber 120 accommodates the substrate holding and rotating mechanism 130 and the recovery cup 160. A fan filter unit (FFU) 121 is provided on the top of the chamber 120. The FFU 121 is used to form a downflow in the chamber 20.

[0031] The substrate holding and rotating mechanism 130 includes a substrate holding portion 131, a support portion (rotation axis) 132, and a rotation driving portion 133. The substrate holding portion 131 is configured as a mechanical holding disk having a disk-shaped base 131a and a plurality of gripping claws 131b arranged at intervals in the circumferential direction on the outer peripheral edge of the base 131a. The substrate holding portion 131 holds the substrate W horizontally by the gripping claws 131b. When the gripping claws 131b grip the substrate, a gap is formed between the upper surface of the base 131a and the lower surface of the substrate W.

[0032] The support part 132 is a hollow member extending in the vertical direction. The upper end of the support part 132 is connected to the base 131a. The support part 132 is rotated by the rotation drive part 133 composed of, for example, an electric motor, so that the substrate holding part 131 and the substrate W held by the substrate holding part 131 rotate around the vertical axis.

[0033] The recovery cup 160 is configured to surround the substrate holding portion 131. The recovery cup 160 captures the processing liquid scattered from the substrate W that is held by the substrate holding portion 131 and rotates. A drain port 161 is formed at the bottom of the recovery cup 160. The processing liquid captured by the recovery cup 160 is discharged to the outside of the liquid processing unit 100 from the drain port 161. An exhaust port 162 is formed at the bottom of the recovery cup 160. The internal space of the recovery cup 160 is suctioned via the exhaust port 162. The gas supplied from the FFU 121 is discharged to the outside of the liquid processing unit 100 via the exhaust port 162 after being introduced into the inside of the recovery cup 160.

[0034] The first processing fluid supply unit 140 supplies various processing fluids (liquids, gases, gas-liquid mixed fluids, etc.) to the upper surface of the substrate W (the surface of the substrate W on which the device is formed) held by the substrate holding portion 131. The first processing fluid supply unit 140 has one or more surface nozzles 141 that eject the processing fluid toward the surface of the substrate W. The number of the surface nozzles 141 is set to the number required for performing the processing executed in the liquid processing unit 100. Figure 2 Five surface nozzles 141 are depicted therein, but the number is not limited thereto.

[0035] The first processing fluid supply unit 140 has one or more (two in the illustrated example) nozzle arms 142. Each nozzle arm 142 carries at least one of the plurality of surface nozzles 141. Each nozzle arm 142 can move the carried surface nozzle 141 between a position (processing position) substantially directly above the rotation center of the substrate W and a retracted position (original position) outside the upper end opening of the recovery cup 160.

[0036] Each surface nozzle 141 is supplied with the processing fluid by a corresponding processing fluid supply mechanism 143. The processing fluid supply mechanism 143 can be composed of a processing fluid supply source such as a tank, a gas cylinder, and a factory supply energy (Japanese: 工場用力), a supply pipe for supplying the processing fluid (processing liquid or processing gas) from the processing fluid supply source to the surface nozzle 141, and flow rate regulating devices such as an on-off valve and a flow rate control valve provided in the supply pipe. In order to discharge the processing fluid (especially the processing liquid) remaining in the supply pipe in the surface nozzle 141 and its vicinity, a discharge pipe can be connected to the supply pipe. Such a processing fluid supply mechanism 143 is widely known in the technical field of semiconductor manufacturing apparatuses, and thus the illustration and detailed description of its structure are omitted. A liquid receiver (not shown) is provided so that dummy-dispense can be performed when each surface nozzle 141 is in the retracted position.

[0037] The second processing fluid supply unit 150 supplies various processing fluids (processing liquid, processing gas, etc.) to the lower surface of the substrate W held by the substrate holding unit 131 (usually the back surface of the substrate W without devices formed thereon). The second processing fluid supply unit 150 has one or more (two in the example shown) back surface nozzles 151 for spraying the processing fluid toward the lower surface of the substrate W. Figure 2 As schematically shown in FIG. 1 , a processing liquid supply pipe 152 extends in the vertical direction inside the hollow support portion 132. The upper end openings of the two flow paths extending in the vertical direction in the processing liquid supply pipe 152 each serve as the back nozzle 151. The processing liquid supply pipe 152 is provided in the support portion 132 in such a manner that the non-rotating state can be maintained even when the substrate holding portion 131 and the support portion 132 rotate.

[0038] Each back side nozzle 151 is supplied with a treatment fluid by a corresponding treatment fluid supply mechanism 153. The treatment fluid supply mechanism 153 has the same structure as the treatment fluid supply mechanism 143 for the surface nozzle 141 described above.

[0039] The second processing fluid supply unit 150 is also configured to supply a drying gas to the space below the substrate W (specifically, the space between the back side of the substrate W and the disc-shaped base 131a of the substrate holding unit 131). This structure can be achieved by providing a gas supply path (not shown) in the processing liquid supply pipe 152 that is the same as the flow path for supplying the processing liquid, or by using the gap between the outer peripheral surface of the processing liquid supply pipe 152 and the inner peripheral surface of the support portion 132 and the base 131a as the gas supply path. As the drying gas, a gas with low humidity and low oxygen concentration is preferably used, and nitrogen (N 2 Such a drying gas can also be supplied from the processing fluid supply mechanism 153.

[0040] In addition, it is known that a plurality of flow paths that can be switched are provided inside the recovery cup 160, and a discharge port 161 corresponding to each flow path is provided to discharge different types of liquids (acid, alkali, organic) through different paths. In addition, it is also known that a switching mechanism is provided at the exhaust port 162 to make different types of liquids (acid, alkali, organic) flow to different discharge destinations. In order to simplify the drawings, the illustration of the structures associated with these functions is omitted.

[0041] <Supercritical Drying Unit>

[0042] Next, refer to Figure 3 The supercritical drying unit 200 will be described. The supercritical drying unit 200 includes a processing container 211 and a substrate holding tray 212 (hereinafter simply referred to as “tray 212 ”) that holds the substrate W in the processing container 211 .

[0043] The tray 212 includes a cover 213 for closing an opening 211C provided in a side wall of the processing container 211, and a substrate holding portion 214 integrally connected to the cover (cover body) 213 and extending in the horizontal direction. The substrate holding portion 214 includes a plate 215 and a plurality of support pins 216 provided on the upper surface of the plate 215. The substrate W is placed on the support pins 216 in a horizontal posture with its surface (the surface on which the device or pattern is formed) facing upward. When the substrate W is placed on the support pins 216, a gap 217 is formed between the upper surface of the plate 215 and the lower surface (back surface) of the substrate W.

[0044] The plate 215 has a plurality of through holes 218 extending vertically through the plate 215. The plurality of through holes 218 serve to allow the processing fluid supplied to the space below the plate 215 to flow into the space above the plate 215. Some of the plurality of through holes 218 also serve to allow the tray 212 (see FIG. 214 ) pulled out of the processing container 211 to flow into the space above the plate 215. Figure 1 ) of the substrate holding portion 214 and the conveying device 16 (refer to Figure 1 ) for transferring the substrate W between the lifting pins (in Figure 1 The effect of the passage of the tray 212 is shown directly below the tray 212 but is obscured by the tray 212 and cannot be observed.

[0045] The tray 212 can be moved by the tray moving mechanism 212M (only Figure 1 ) to the closed position ( Figure 3 Position shown) and open position ( Figure 1 The position shown in FIG. 1 is a perspective view of a moving part of a mobile phone. The moving part of the mobile phone is a horizontal position (X direction) between the positions shown in FIG. 1 and FIG.

[0046] In the closed position of the tray 212, the substrate holding portion 214 is located in the internal space of the processing container 211, and the cover portion 213 closes the opening 211C of the side wall of the processing container 211. In the open position of the tray 212, the substrate holding portion 214 is out of the processing container 211 (see Figure 1 ) The substrate W can be transferred between the substrate holding portion 214 and a substrate transfer arm (not shown) via the above-mentioned lifting pins.

[0047] When the tray 212 is in the closed position, the internal space of the processing container 211 is divided by the plate 215 into an upper space 211A above the plate 215 where the substrate W is located during processing, and a lower space 211B below the plate 215. However, the upper space 211A and the lower space 211B are not completely separated, and the upper space 211A and the lower space 211B are connected, for example, through the through hole 218, the long hole 219, and the gap between the peripheral edge of the plate 215 and the inner wall surface of the processing container 211.

[0048] The processing container 211 is provided with a first ejection part 221 and a second ejection part 22. The first ejection part 221 and the second ejection part 22 eject the processing fluid (in this example, carbon dioxide (hereinafter, for simplicity, also referred to as "CO2")) supplied from a supply source (not shown) of a supercritical fluid (processing fluid in a supercritical state) into the inner space of the processing container 211.

[0049] The first ejection part 221 is provided below the plate 215 of the tray 212 in the closed position. The first ejection part 221 ejects CO 2 (process fluid) toward the lower surface of the plate 215 (upward) into the lower space 211B.

[0050] The second discharge unit 22 is provided in front of the substrate W placed on the substrate holding unit 214 of the tray 212 in the closed position (a position advanced in the positive X direction). The second discharge unit 22 supplies CO 2 into the upper space 211A.

[0051] The second ejection part 22 is composed of a rod-shaped nozzle body. In detail, the second ejection part 22 is formed by penetrating a plurality of ejection ports 22b on a tube 22a extending in the width direction (Y direction) of the substrate W. The plurality of ejection ports 22b are arranged at equal intervals in the Y direction, for example. Each ejection port 222b supplies CO2 into the upper space 212A toward one side of the opening 211C (towards the substantially negative X direction).

[0052] The processing container 211 is also provided with a fluid discharge portion 224 for discharging the processing fluid from the internal space of the processing container 211. The fluid discharge portion 224 is configured as a manifold having a structure substantially the same as that of the second ejection portion 22. In detail, the fluid discharge portion 224 is formed by passing a plurality of discharge ports 224b through a tube 224a extending in a horizontal direction. The plurality of discharge ports 224b are arranged at equal intervals in the Y direction, for example. Each discharge port 224b faces upward and faces one side of the long hole 219 formed in the plate 215.

[0053] like Figure 1 As shown by the middle arrow F, after flowing through the area above the substrate W in the upper space 211A, CO2 flows into the lower space 211B through the connecting path provided in the peripheral portion of the plate 215 (or the long hole 219 formed in the plate 215), and is then discharged from the fluid discharge portion 224.

[0054] The processing unit 210 is provided with a locking mechanism 225 having a latch-shaped locking member 225C for fixing the tray 212 in the closed position and a latch-shaped locking member 225C for locking the locking member 225C in the locked position ( Figure 3 A lifting device 225B is provided for lifting between a locked position (as shown in the figure) and an unlocked position lowered from the locked position.

[0055] <Supercritical drying treatment>

[0056] Next, the process performed in the supercritical drying unit 200 will be briefly described.

[0057] [Substrate loading process]

[0058] The substrate W having the IPA liquid mass formed on the surface in the liquid processing unit 100 is taken out of the liquid processing unit 100 by the conveying device 16 in the conveying area 15 and is conveyed into the supercritical drying unit 200. In the supercritical drying unit 200, the tray 212 is in the open position ( Figure 1 The above-mentioned lifting pins (not shown) are inserted into through holes (not shown) formed in the substrate holding portion 214 of the tray 212, and the front ends of the lifting pins are located above the substrate holding portion 214. The transport device 16 places the substrate W on the lifting pins, and then the lifting pins are lowered, thereby placing the substrate W on the tray 212. Then, the tray 212 moves to the closed position, accommodates the substrate W in the processing container 211, and seals the processing container 211. In this state, the supercritical drying process is performed.

[0059] [Pressure Boosting Process]

[0060] First, a pressure increasing step is performed.

[0061] CO2 (processing fluid) supplied from the supply source of the supercritical processing fluid is ejected from the first ejection part 221 into the lower space 211B of the processing container 211. When the supply of CO2 just starts, the processing container 211 is at normal pressure, so the gaseous CO2 is ejected from the first ejection part 221 at a high flow rate. After the momentum of CO2 is weakened by colliding with the lower surface of the plate 215, it flows into the upper space 211A in the processing container 211 through the through hole 218 and the long hole 219 or through the gap between the peripheral portion of the plate 215 and the inner wall surface of the processing container 211. With the inflow of CO2, the internal pressure in the processing container 211 gradually increases.

[0062] When the pressure in the processing container 211 exceeds the critical pressure of CO2 (about 8 MPa), the CO2 (CO2 not mixed with IPA) in the processing container 211 becomes supercritical. When the CO2 in the processing container 211 becomes supercritical, the IPA on the substrate W begins to dissolve into the CO2 in the supercritical state. Then, CO2 is continuously ejected from the first ejection part 221 to further increase the pressure in the processing container 211.

[0063] [Distribution process]

[0064] When the pressure in the processing container 211 reaches a pressure (supercritical state guarantee pressure (about 16 MPa)) that ensures that the mixed fluid (CO2+IPA) on the substrate W is maintained in a supercritical state regardless of the IPA concentration in the mixed fluid (CO2+IPA) and the temperature of the mixed fluid, the CO2 is stopped from being ejected from the first ejection part 221, and the CO2 is started to be ejected from the second ejection part 22, and the CO2 is started to be discharged from the fluid discharge part 224. By controlling the discharge flow rate from the fluid discharge part 224, CO2 is allowed to flow in the processing container 211 while the pressure in the processing container 211 is maintained at the supercritical state guarantee pressure. In the circulation process, the supercritical CO2 supplied from the second ejection part 22 to the processing container 211 flows in the upper area of ​​the substrate, and is then discharged from the fluid discharge part 24 (refer to Figure 3 At this time, a laminar flow of supercritical CO2 is formed in the processing container 211, flowing substantially parallel to the surface of the substrate W. The IPA in the mixed fluid (IPA+CO2) on the surface of the substrate W exposed to the laminar flow of supercritical CO2 is replaced by supercritical CO2. Ultimately, almost all of the IPA on the surface of the substrate W is replaced by supercritical CO2.

[0065] [Discharging process]

[0066] After the replacement from IPA to supercritical CO2 is completed, the supply of CO2 to the processing container 211 is stopped, and the processing container 211 is connected to the atmospheric atmosphere via the fluid discharge unit 224. As a result, the pressure in the processing container 211 is reduced to normal pressure. Along with this, the supercritical CO2 in the pattern of the substrate W becomes gas and is separated from the pattern, and the gaseous CO2 is discharged from the processing container 211. Through the above, the drying of the substrate W (substrate drying process) is completed.

[0067] [Substrate removal process]

[0068] The tray 212 carrying the dried substrate W is moved to the open position, and the substrate is unloaded from the supercritical drying unit 200 using the lift pins (not shown) and the transfer device 16 in the reverse process of the substrate loading step.

[0069] <Liquid treatment>

[0070] Next, a series of steps performed in liquid processing unit 100 will be described.

[0071] In the following, the description will be given on the premise that liquid processing unit 100 has the following structure.

[0072] - The first processing fluid supply unit 140 includes two nozzle arms 142, one of the nozzle arms 142 is also referred to as "arm R", and the other of the nozzle arms 142 is also referred to as "arm L",

[0073] - A surface nozzle 141 (also called "surface nozzle F1") that selectively sprays HF (hydrofluoric acid) and DIW (pure water), and a surface nozzle 141 (also called "surface nozzle F2") that sprays IPA (isopropyl alcohol) are carried at the front end of the arm R.

[0074] - The front end of the arm L carries a surface nozzle 141 (also referred to as "surface nozzle F3") for ejecting DIW and a surface nozzle 141 (also referred to as "surface nozzle F4") for ejecting a water-repellent liquid (such as organosilane).

[0075] -The second processing fluid supply unit 150 has a back nozzle 151 (also referred to as "back nozzle B1") for ejecting DIW and a back nozzle 151 (also referred to as "back nozzle B2") for ejecting IPA. In addition, the back nozzles B1 and B2 are both configured to eject liquid in such a manner that the liquid lands on a position slightly away from the center of the back side of the substrate W (the rotation center of the substrate). Alternatively, one of the back nozzles B1 and B2 ejects liquid in such a manner that the liquid lands on the rotation center of the substrate W, and the other ejects liquid in such a manner that the liquid lands on a position slightly away from the rotation center of the substrate W. In either case, the back nozzles B1 and B2 eject liquid in such a manner that the liquid lands on the "center portion" of the substrate in the definition described below.

[0076] Next, each process is described. Figure 4A to Figure 4L ), in order to simplify the drawings, "R" and "L" are used as reference numerals for the nozzle arm 142, "F1", "F2", "F3", and "F4" are used as reference numerals for the surface nozzle 141, and "B1" and "B2" are used as reference numerals for the back nozzle 151. Figure 4A to Figure 4L In the figure, it is to be understood that the surface nozzle 141 located outside the substrate W is located at the home position (standby position).

[0077] [Chemical cleaning process]

[0078] The substrate W carried into the liquid processing unit 100 by the transport device 16 is held in a horizontal position by the substrate holding portion 131 of the substrate holding and rotating mechanism 130. The substrate W is rotated about a vertical axis by the substrate holding and rotating mechanism 130. The rotation speed of the substrate W is changed as required, and the rotation of the substrate W is continued until a series of steps are completed.

[0079] In this state, if Figure 4AAs shown, the surface nozzle F1 of the arm R is located directly above the center of the substrate W, and supplies the liquid, here HF, in such a way that the liquid lands on the center of the substrate W. Regarding the landing position, the center of the substrate W is not limited to the center (rotation center) of the substrate. The concept of the center of the substrate W also includes the following positions: a position on the surface of the substrate W that is slightly away from the center of the substrate W, and after the liquid (here HF) lands at this position, the liquid will expand to the center of the substrate along the momentum of the landing. HF flows toward the periphery of the substrate W while expanding in a manner covering the entire surface area of ​​the substrate W due to centrifugal force. As a result, the silicon oxide film on the surface of the substrate W is removed by HF.

[0080] It is preferred that DIW is ejected from the back nozzle B1 while HF is being supplied to the center of the substrate W by the surface nozzle F1. The DIW that has landed on the center of the back of the substrate flows toward the periphery of the substrate W while expanding to cover the entire back area of ​​the substrate W by centrifugal force. In other words, the entire back area of ​​the substrate W is covered by the liquid film of DIW. Therefore, it is possible to prevent HF on the surface of the substrate W from flowing toward the back through the periphery (APEX) of the substrate W, thereby preventing the back of the substrate W from being contaminated by contaminants derived from, for example, reaction products.

[0081] Furthermore, before the chemical liquid cleaning step, a pre-wetting process may be performed in which DIW is supplied from the surface nozzle F1 of the arm R to the center of the surface of the rotating substrate W to temporarily cover the entire surface of the substrate with a DIW liquid film.

[0082] [Rinsing process]

[0083] Then, if Figure 4B As shown in FIG. 1 , the position of the surface nozzle F1 is maintained unchanged, and the processing liquid ejected from the surface nozzle F1 is switched from HF to DIW. The DIW supplied to the center of the substrate W flows toward the periphery of the substrate W while spreading to cover the entire surface area of ​​the substrate W by centrifugal force. Thus, the HF remaining on the surface of the substrate W and the reaction products generated in the chemical solution cleaning step are washed away from the surface of the substrate W.

[0084] It is preferable that DIW is continuously discharged from the back surface nozzle B1 until the rinsing progresses to a certain extent and the HF remaining on the surface of the substrate W and the reaction products generated in the chemical solution cleaning step are sufficiently removed.

[0085] Then, if Figure 4CAs shown, while continuing to spray DIW from the surface nozzle F1, the surface nozzle F3 of arm L is positioned above the substrate W and starts to spray DIW from the surface nozzle F3. Then, while continuing to spray DIW from the surface nozzle F3, the surface nozzle F3 is moved closer to the surface nozzle F1. At this time, after arm L approaches arm R, arm R starts to retreat so that arm L does not collide with arm R. That is, before the surface nozzle F3 carried by arm L reaches directly above the center of substrate W, the surface nozzle F1 carried by arm R is retreated to a position slightly deviated from directly above the center of substrate W. When as Figure 4D When the surface nozzle F3 ejecting DIW reaches the center of the substrate W, the surface nozzle F1 stops ejecting DIW. The positions of the surface nozzle F1 and the arm R carrying the surface nozzle F1 (also referred to as "temporary retreat position") remain unchanged.

[0086] [IPA replacement process (DIW → IPA)]

[0087] Then, if Figure 4E As shown, while continuing to spray DIW from the surface nozzle F3 located just above the center of the substrate W, IPA starts to be sprayed from the surface nozzle F2 carried by the arm R in the temporary retreat position. Then, while continuing to spray DIW from the surface nozzle F3, the surface nozzle F2 is moved closer to the surface nozzle F3. At this time, when the arm R and the arm L are close, the arm L starts to retreat so that the arm R does not collide with the arm L. That is, before the surface nozzle F2 carried by the arm R reaches just above the center of the substrate W, the surface nozzle F1 carried by the arm L is moved from just above the center of the substrate W toward the peripheral side of the substrate W. As shown Figure 4F As shown in the figure, when the surface nozzle F2 ejecting IPA reaches the center of the substrate W, the surface nozzle F2 is stopped at this position, and the ejection of DIW from the surface nozzle F3 is stopped. Then, the surface nozzle F3 and the arm L carrying the surface nozzle F3 are moved to the home position and are made to wait at this position.

[0088] By continuing the ejection of IPA from the surface nozzle F2 located just above the center of the substrate W for a predetermined time, DIW on the surface of the substrate W (including the inside of the concave portion of the pattern formed on the surface) is replaced with IPA. Since the water-repellent used in the next step of the water-repellent treatment process has a low affinity with DIW, it is difficult to directly replace DIW with the water-repellent. Therefore, a process is followed in which DIW is temporarily replaced with IPA having a high affinity with DIW, and then replaced with a water-repellent agent having a high affinity with IPA.

[0089] In the next step of the water repellent treatment process, the water repellent agent (SM) supplied to the surface of the substrate W may flow around the periphery (APEX) of the substrate W and enter the back peripheral portion (see Figure 5 ). Such wrapping may occur in all liquids (PL), although the extent of the wrapping may vary. At this time, if the DIW supplied to the back side of the substrate W in the rinsing process is not dried and remains, for example, Figure 5 In the area surrounded by the dotted line, the water-repellent reacts with water to produce stains (attachments), which become the cause of particles during the subsequent supercritical drying process. In order to prevent this phenomenon, in the IPA replacement process (DIW→IPA), it is preferred to supply the above-mentioned drying gas (here nitrogen) to the back side of the substrate. By supplying a drying gas to remove the moisture remaining on the back side of the substrate W, the generation of the above-mentioned stains (attachments) can be prevented. In addition, in the IPA replacement process, sometimes the IPA supplied to the surface of the substrate W passes through the periphery (APEX) of the substrate W and is wrapped around the back peripheral portion. The IPA attached to the back peripheral portion promotes the wrapping of the water-repellent agent supplied to the surface of the substrate W in the water-repellent treatment process to the back side. That is, if the water-repellent agent contacts the IPA attached to the back peripheral portion, it will be attracted by the IPA. This is not preferred from the viewpoint of inhibiting the adhesion of substances derived from the water-repellent agent to the back side. From this point of view, it is also preferred to supply the above-mentioned drying gas to the back side of the substrate in the IPA replacement process (DIW→IPA), and from this point of view, it is preferred to continue to spray the drying gas until just before the switching process of the next process (IPA→waterproofing agent) starts.

[0090] [Switching process (IPA → water-repellent agent)]

[0091] Next, while continuing to spray IPA from the surface nozzle F2, the arm L is moved to bring the surface nozzle F4 closer to the surface nozzle F2. At this time, when the arm L and the arm R are close, the arm R is made to retreat so that the arm L does not collide with the arm R. In other words, the surface nozzle F2 is moved to move away from the position directly above the center of the substrate W. In addition, almost at the same time, the hydrophobic agent (marked with the reference symbol "SM" in the figure) is started to be sprayed from the surface nozzle F4 (refer to Figure 4G ).

[0092] When the surface nozzle F4 spraying the hydrophobizing agent reaches the center of the substrate W, the surface nozzle F4 is stopped at this position. At the same time, the spraying of IPA from the surface nozzle F2 is stopped, and the surface nozzle F2 and the arm R carrying the surface nozzle F2 are moved to the original position and made to stand by at this position (refer to Figure 4H ).

[0093] In addition, in this switching process (IPA→waterproofing agent), as long as the surface of the substrate W is kept covered with a liquid film, it is not necessary to strictly determine the timing of starting to spray the water-repellent agent from the surface nozzle F4 and the timing of stopping to spray the IPA from the surface nozzle F2. The timing of starting to spray the water-repellent agent can be advanced, and the timing of stopping to spray the IPA can be delayed. However, in general, since IPA and the water-repellent agent are relatively expensive liquid chemicals, the above timing is determined in a manner that can reduce useless consumption.

[0094] [Waterproofing process]

[0095] like Figure 4H As shown, the spraying of the water-repellent agent from the surface nozzle F4 is continued for a predetermined time starting from the time point when the surface nozzle F4 spraying the water-repellent agent is located directly above the center of the substrate W. As a result, the IPA on the surface of the substrate W (including the inside of the concave portion of the pattern formed on the surface) is replaced with the water-repellent agent. After that, the spraying of the water-repellent agent from the surface nozzle F4 is continued for a predetermined time, whereby the surface of the substrate W (including the inside of the concave portion of the pattern formed on the surface) is water-repellent to a desired level by the water-repellent agent.

[0096] As the water-repellent agent, for example, a silylating agent can be used, and examples of the silylating agent include trimethylsilyldimethylamine (TMSDMA), hexamethyldisilazane (HMDS), trimethylsilyldiethylamine (TMSDEA), dimethyl(dimethylamino)silane (DMSDMA), and 1,1,3,3-tetramethyldisilane (TMDS).

[0097] [Switching process (waterproofing agent → IPA)]

[0098] Then, if Fig. 4I As shown, while continuing to spray the water repellent from the surface nozzle F4 located just above the center of the substrate W, the arm R is moved to bring the surface nozzle F2 closer to the surface nozzle F4. At this time, after the arm R approaches the arm L, the arm L starts to retreat so that the arm R does not collide with the arm L. In other words, the surface nozzle F4 starts to move away from the position just above the center of the substrate W. In addition, almost simultaneously, IPA starts to be sprayed from the surface nozzle F2. When the surface nozzle F2 spraying IPA reaches just above the center of the substrate W, the surface nozzle F2 is stopped at this position, and almost simultaneously, the spraying of the water repellent from the surface nozzle F4 is stopped. The surface nozzle F4 that has stopped spraying the water repellent and the arm L carrying the surface nozzle F4 are moved to the original position and are placed on standby at this position.

[0099] In addition, in this switching process (water-repellent agent → IPA), as long as the surface of the substrate W is maintained covered with a liquid film, there is no need to strictly determine the timing for starting to spray IPA from the surface nozzle F2 and the timing for stopping to spray the water-repellent agent from the surface nozzle F4. The timing for starting to spray IPA can be advanced, and the timing for stopping to spray the water-repellent agent can be delayed.

[0100] [IPA liquid film forming step (IPA replacement step)]

[0101] Starting from the time when the surface nozzle F2 ejecting IPA reaches the center of the substrate W, the ejection of IPA from the surface nozzle F2 is continued for a predetermined time, so that the entire surface area of ​​the substrate W is covered with the liquid film of IPA, and the water repellent on the surface of the substrate W (including the inside of the concave part of the pattern formed on the surface) is replaced with IPA. In addition, at least during the period of performing the IPA liquid film forming process (liquid film forming process), the back side of the substrate W is subjected to a back side cleaning process, which will be described later.

[0102] [IPA film thickness adjustment process]

[0103] Next, while continuing to eject IPA from the surface nozzle F2 located just above the center of the substrate W, the rotation speed of the substrate W is reduced from, for example, 1000 rpm to a lower speed, for example, about 300 rpm to 700 rpm (see Figure 4K ). Next, the rotation speed of the substrate is reduced to a final rotation speed of extremely low speed, for example, 30 rpm, and the ejection of IPA from the surface nozzle F2 is stopped (see Figure 4L ). The thickness of the IPA liquid mass (liquid film) remaining on the surface of the substrate W can be adjusted by appropriately adjusting the final rotation speed. Finally, the rotation of the substrate W is stopped. Through the above, a series of steps performed in the liquid processing unit 100 are completed. As a result, the pattern on the surface of the substrate W is protected by the IPA as a protective liquid.

[0104] The substrate W on which the IPA liquid mass is formed is carried out from the liquid processing unit 100 by the transport device 16 and is carried into the supercritical drying unit 200 , where the substrate W is subjected to the above-described supercritical drying process.

[0105] [Back cleaning process (cleaning process)]

[0106] At least during the execution of the IPA liquid film forming step, the back cleaning step is performed. If the water repellent supplied to the surface of the substrate W in the water repellent treatment step flows around to the back of the substrate W and, for example, Figure 5If the area indicated by the dotted line in the figure is dry (including becoming a semi-dry state), it may dissolve into the supercritical fluid (CO2, or a mixture of CO2 and IPA) during supercritical drying and become the cause of particles. That is, in the above-mentioned supercritical drying process, the CO2 ejected from the first ejection part 221 into the lower space 211B of the processing container 211 flows along the back of the substrate W after passing through the through hole 218, and flows into the upper space 211A near the peripheral portion of the back of the substrate W. If a substance derived from the water-repellent agent is attached to the peripheral portion of the back of the substrate W, the substance dissolves in the CO2 and becomes the cause of particles. In addition, in the circulation process of the supercritical drying process, a part of the CO2 flowing near the surface of the substrate W flows from the gap between the peripheral portion of the substrate W and the plate 215 of the tray 212 to the gap between the upper surface of the plate 215 and the back of the substrate W. If the substance derived from the water-repellent agent attached to the peripheral portion of the back side of the substrate W contacts the CO2 flow, the substance dissolves in the CO2 and becomes a cause of particles. In order to prevent the generation of particles due to the above mechanism, a back side cleaning process is performed to remove the water-repellent agent that has been wound around the back side of the substrate W. The back side cleaning process is described below.

[0107] The back cleaning process can be performed by supplying a cleaning liquid such as IPA to the center of the back side of the rotating substrate W. Fig. 4I and Figure 4J Indicated by reference figure mark CL. The cleaning liquid supplied to the central part of the back side of the substrate W flows toward the peripheral part of the back side by centrifugal force, so that the entire area of ​​the back side is covered with the cleaning liquid. This state is continued for a predetermined time, whereby the back side of the substrate W is cleaned, and in particular, the water-repellent agent (or attachments derived from the water-repellent agent) attached to the peripheral part of the back side is removed. In addition, the temperature of the cleaning liquid is preferably set to a medium temperature range between 20°C and 75°C. In this way, the removal efficiency of the water-repellent agent (here, the silylating agent) can be improved.

[0108] Preferably, the supply flow rate of the cleaning liquid to the back side of the substrate W in the back side cleaning process is smaller than the supply flow rate of IPA (protective liquid) to the surface of the substrate W at the same time. In this way, the cleaning liquid can be prevented from flowing around from the back side to the surface. For example, contaminants from the back side attachments may be mixed into the cleaning liquid, so from the viewpoint of preventing contamination of the surface of the substrate W, it is preferable to prevent the cleaning liquid supplied to the back side from flowing around to the surface.

[0109] The end time point of the back cleaning process is when the water-repellent agent that has been carried around to the back is completely or almost completely removed (end condition 1), and the water-repellent agent is no longer able to carry around from the surface of the substrate W to the back (end condition 2). End condition 2 is equivalent to the water-repellent agent on the surface of the substrate W being completely or almost completely replaced by IPA. In addition, the above-mentioned "almost completely" means that even if there is a very small amount of water-repellent agent remaining, its effect on the generation of particles during supercritical drying can be ignored.

[0110] The time required from the start time point of the IPA liquid film forming process (the end time point of the switching process (water-repellent agent → IPA)), that is, the time point when the surface nozzle F2 ejecting IPA is located directly above the center of the substrate W (hereinafter, for simplicity, also referred to as "time point T1") to the time when the water-repellent agent on the surface of the substrate W is substantially completely replaced by IPA (hereinafter also referred to as "required replacement time") is, for example, 20 seconds (which varies depending on the processing conditions). In this case, the end condition 2 is satisfied at the time point after 20 seconds from the time point T1.

[0111] The time required for the water-repellent agent that has been wound into the back surface to be completely or almost completely removed (hereinafter also referred to as "time required for back cleaning") is at most the same level as the "time required for replacement". Therefore, the back cleaning process and the switching process (water-repellent agent → IPA) can be started at the same timing and ended at the same timing. In other words, if the back cleaning process is started at time point T1, the back cleaning process can be stopped (ended) at the end time point of the IPA liquid film formation process (IPA replacement process) (the time point after 20 seconds from time point T1).

[0112] The back cleaning process can also be started before time point T1, for example, at the same time as the switching process (waterproofing agent → IPA) starts or in the middle of the switching process (waterproofing agent → IPA). By starting the back cleaning process in advance, the removal of the water-repellent agent attached to the back side of the substrate W (especially the peripheral part of the back side) can be completed in advance, so that the back cleaning process can be ended in advance. When the back cleaning process is ended early, the subsequent drying of the back side can also be ended early. In the case of requiring drying of the back side, even if the IPA liquid film forming process (IPA replacement process) is completed, it is necessary to wait until the back side is dry before entering the IPA film thickness adjustment process implemented by low-speed rotation. Therefore, depending on the situation (for example, when the cleaning liquid is DIW), the IPA liquid film forming process (IPA replacement process) must be unnecessarily extended, which may cause problems such as unnecessary increase in the amount of IPA supplied to the surface of the substrate W and longer processing time (resulting in reduced throughput). Such problems can be solved by starting the back cleaning process in advance.

[0113] In addition, it may be thought that if the back cleaning process is ended before the IPA liquid film forming process (IPA replacement process) is completed, the water-repellent agent remaining on the surface of the substrate will go around to the back and contaminate the back, but this will not happen in actual processing. In actual processing, the processing time will be slightly longer to reliably avoid the water-repellent agent being included in the IPA liquid mass. In other words, the time obtained by adding the safety margin time to the time required to completely replace the water-repellent agent with IPA (replacement required time) is set as the processing time. In other words, at the end time point of the replacement required time, the IPA on the surface of the substrate W does not contain any water-repellent agent at all, or even if it does, it is only a very small amount. Even if such an IPA goes around to the back, it will not substantially cause problems in the state of the back. In other words, the back cleaning process can be ended at the start time point of the safety margin time at the latest. Therefore, there is no problem even if the start of the back cleaning process is advanced by at least the safety margin time.

[0114] In addition, Fig. 4I and Figure 4J 2 shows an example in which IPA as the cleaning liquid is ejected from the back nozzle B2 in the middle of the switching process (water repellent → IPA).

[0115] When the IPA is stopped from being ejected from the back nozzle B2 while the substrate W is being rotated, the cleaning liquid on the back side of the substrate W is shaken off and the back side is dried. In the case where the back side is expected to be fully dried, the substrate W can be rotated at a relatively high speed (e.g., 1000 rpm) for a predetermined time (e.g., about 10 seconds when the cleaning liquid is IPA) after the back side cleaning process is completed (i.e., after the cleaning liquid is stopped from being ejected from the back side nozzle B2).

[0116] Even if the substrate W is unloaded from the liquid processing unit, loaded into the supercritical processing unit, and subjected to supercritical processing while IPA is attached to the back side of the substrate W, there will be no problem in most cases. On the contrary, it may help maintain the IPA liquid mass in the processing container of the supercritical processing unit. Therefore, after stopping the spraying of IPA from the back side nozzle B2, the rotation speed of the substrate W may be immediately reduced without providing time for drying the back side to adjust the film thickness of IPA.

[0117] The cleaning liquid (CL) used in the back cleaning process is not limited to IPA, but can also be other cleaning liquids such as DIW. In this case, the cleaning liquid only needs to be sprayed from the back nozzle L1. DIW also has a removal performance of attachments from the waterproofing agent that is roughly equivalent to IPA. However, if supercritical drying is performed in a state where DIW is attached to the back of the substrate W, problems will arise as a result of supercritical drying (pattern collapse, particle generation). Therefore, it is necessary to fully dry the back side before the substrate W is removed from the liquid processing unit. For drying, as in the case of using IPA as a cleaning liquid, it is sufficient to rotate the substrate W at a relatively high speed (for example, 1000 rpm) for a predetermined time after the back cleaning process is completed (that is, after stopping the spraying of DIW from the back nozzle B1). It takes longer time to dry the DIW on the back side than to dry IPA (for example, about 40 seconds at 1000 rpm). In addition, a drying gas (nitrogen) can also be blown to the back side of the substrate W to promote the drying of the DIW on the back side.

[0118] DIW is cheaper than IPA, so it has the advantage of reducing the running cost of the device. On the other hand, IPA has a higher volatility than DIW, so it has the advantage of being able to shorten the required time for drying the back side. As for which one of DIW and IPA to use as the cleaning liquid on the back side, it is enough to decide by considering such a compromise relationship. In addition, some waterproofing agents also have problems when coexisting with moisture (water), so when using such waterproofing agents, it is desirable to use IPA as the cleaning liquid. In addition, as the cleaning liquid (CL) used in the back cleaning process, a mixed liquid of DIW and IPA can also be used.

[0119] [experiment]

[0120] The following experiment was conducted: using the liquid processing unit 100 and the supercritical drying unit 200, a substrate was subjected to liquid processing and supercritical drying processing by the following four methods, and the amount of particles was compared.

[0121] <Processing method 1 (reference example)>

[0122] DIW pre-wetting → chemical cleaning process (HF cleaning) → rinsing process (DIW rinsing) → IPA replacement process (DIW → IPA) → switching process (IPA → water-repellent agent) → water-repellent treatment process → switching process (water-repellent agent → IPA) → IPA liquid film formation process (IPA replacement process) → spin drying process (supercritical drying is not used in the final drying)

[0123] <Treatment Method 2 (Comparative Example 1)>

[0124] DIW pre-wetting → chemical cleaning process (HF cleaning) → rinsing process (DIW rinsing) → IPA replacement process (DIW→IPA) (no drying gas is supplied to the back side at this time) → switching process (IPA→waterproofing agent) → water-repellent treatment process → switching process (waterproofing agent→IPA) → IPA liquid film forming process (IPA replacement process) (the back side cleaning process is not performed at this time) → IPA film thickness adjustment process → supercritical drying of the substrate with the IPA liquid mass formed.

[0125] <Treatment Method 3 (Comparative Example 2)>

[0126] DIW pre-wetting → chemical cleaning process (HF cleaning) → rinsing process (DIW rinsing) → IPA replacement process (DIW→IPA) (drying gas is supplied to the back side at this time) → switching process (IPA→waterproofing agent) → water-repellent treatment process → switching process (waterproofing agent→IPA) → IPA liquid film forming process (IPA replacement process) (back side cleaning process is not performed at this time) → IPA film thickness adjustment process → supercritical drying of the substrate with the IPA liquid mass formed.

[0127] <Processing method 4 (Example)>

[0128] DIW pre-wetting → chemical cleaning process (HF cleaning) → rinsing process (DIW rinsing) → IPA replacement process (DIW→IPA) (drying gas is supplied to the back side at this time) → switching process (IPA→waterproofing agent) → water-repellent treatment process → switching process (waterproofing agent→IPA) → IPA liquid film forming process (IPA replacement process) (back side cleaning process is implemented at this time) → IPA film thickness adjustment process → supercritical drying of the substrate with the IPA liquid mass formed.

[0129] The increase in the number of particles larger than 19 nm before and after the treatment was investigated for each substrate W, and the increase was 205 in treatment method 1, 4301 in treatment method 2, 2168 in treatment method 3, and 286 in treatment method 4. In addition, in treatment methods 2 and 3, the particles were significantly distributed in a one-sided manner, which is believed to be caused by the following reasons: it is caused by the uneven flow of CO2 in the gap between the peripheral portion of the substrate W and the plate 215 of the tray 212 in the supercritical drying device (refer to the description at the beginning of the back cleaning process).

[0130] According to the above test results, when supercritical drying is performed after waterproofing treatment, if there is no back cleaning (treatment methods 2 and 3), the number of particles increases significantly (the estimated mechanism has been described above). However, it was confirmed that when the back is cleaned (treatment method 4), the increase in the number of particles is reduced to a level roughly the same as that of treatment method 1. In addition, it goes without saying that treatment method 4 for supercritical drying has an overwhelming advantage over treatment method 1 for spin drying from the perspective of suppressing pattern collapse. In addition, by comparing treatment methods 2 and 3, it can be seen that the increase in particles can be suppressed by supplying drying gas to the back in the IPA replacement process (DIW→IPA).

[0131] As described above, according to the above-mentioned embodiment, by performing the back surface cleaning step in the IPA liquid film forming step (IPA replacement step) on the surface of the substrate W, the amount of particles after supercritical drying can be significantly reduced.

[0132] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the appended claims and the gist thereof.

[0133] The substrate is not limited to a semiconductor wafer, and may be other types of substrates used in manufacturing semiconductor devices, such as a glass substrate and a ceramic substrate.

[0134] The protective liquid is not limited to IPA, and an organic solvent having high affinity with the water repellent and the supercritical fluid used in the supercritical drying process and low surface tension, such as HFE (hydrofluoroether) or a mixture of IPA and HFE, may be used instead of IPA.

[0135] In the above-mentioned embodiment, the process before the first IPA replacement process (DIW→IPA) can be arbitrarily changed. For example, two or more types of liquid treatments may be performed before the first IPA replacement process.

[0136] The purpose of the back cleaning process may be other than the removal of the water repellent or the substance derived from the water repellent. In the case where the peripheral portion of the back side of the substrate is attached with, for example, residues of a chemical solution or reaction products, which may also become particles during supercritical drying, the back cleaning process may be performed for the purpose of removing such substances. In other words, the back cleaning process may be performed for the following purpose: to remove the attachments that may be attached to the back side of the substrate due to the treatment with a treatment liquid (which is not limited to the water repellent, and may also be a chemical solution such as HF) performed prior to the IPA liquid film formation process.

Claims

1. A substrate processing method, comprising: a liquid film forming step of supplying a protective liquid having a pattern for protecting the surface of the substrate to the surface of the substrate after the liquid treatment step using the treatment liquid, so as to form a liquid film of the protective liquid covering the surface of the substrate; a substrate carrying step of carrying the substrate into a processing container after the liquid film forming step in a state where the liquid film of the protective liquid is formed; a substrate drying step, after the substrate carrying step, supplying a pressurized processing fluid to the processing container to maintain the pressure in the processing container at a pressure that allows the processing fluid to maintain a supercritical state, supplying the pressurized processing fluid to the processing container to replace the processing liquid on the substrate with the processing fluid, and discharging the processing fluid from the processing container to dry the substrate; as well as The back surface cleaning step is to supply a cleaning liquid for cleaning the back surface of the substrate to the back surface of the substrate, wherein the back surface cleaning step is performed at least during the period in which the liquid film forming step is performed.

2. The substrate processing method according to claim 1, wherein: The treatment liquid is a water-repellent agent for making the surface of the substrate water-repellent.

3. The substrate processing method according to claim 2, wherein: The cleaning liquid is any one of pure water, isopropyl alcohol, and a mixture of pure water and isopropyl alcohol.

4. The substrate processing method according to claim 2, wherein: The cleaning liquid is isopropanol, and the protection liquid is also isopropanol.

5. The substrate processing method according to claim 3 or 4, wherein: The temperature of the cleaning liquid supplied to the back surface of the substrate is 20°C to 75°C.

6. The substrate processing method according to claim 1, wherein: When the liquid film forming step is performed on the surface of the substrate and the back surface cleaning step is performed on the back surface of the substrate, the supply flow rate of the protection liquid to the surface is equal to or greater than the supply flow rate of the cleaning liquid to the back surface.

7. The substrate processing method according to claim 1, wherein: The back surface cleaning step is ended after a predetermined time has elapsed from the start of the liquid film forming step.

8. The substrate processing method according to claim 2, wherein: Supplying the cleaning liquid in the back surface cleaning step starts when the water repellent agent and the protective liquid are simultaneously supplied to the surface of the substrate to switch from the liquid treatment step using the water repellent agent as the treatment liquid to the liquid film forming step.

9. The substrate processing method according to claim 2, wherein: Supply of the cleaning liquid in the back surface cleaning step is started at the time when switching from the liquid treatment step using the water repellent agent as the treatment liquid to the liquid film forming step is completed, that is, when supply of the water repellent agent is stopped.

10. The substrate processing method according to claim 1, wherein: The protection liquid is supplied to the center of the surface of the rotating substrate, and the cleaning liquid is supplied to a position where the cleaning liquid departs from the center of the back side of the rotating substrate and lands on the back side and then spreads to reach the center of the back side of the substrate.

11. A substrate processing device comprising: at least one liquid processing unit; as well as at least one supercritical drying unit, in, The liquid processing unit comprises: a substrate holding and rotating mechanism that holds the substrate in a horizontal position and rotates the substrate about a vertical axis; as well as a processing fluid supply unit, comprising a processing fluid supply mechanism, at least one surface nozzle and at least one back nozzle, wherein the at least one surface nozzle is capable of supplying at least a processing liquid and a protective liquid to the surface of a substrate held and rotated by the substrate holding and rotating mechanism, and the at least one back nozzle is capable of supplying at least a cleaning liquid to the back of a substrate held and rotated by the substrate holding and rotating mechanism, and the processing fluid supply mechanism supplies liquid required for processing to the at least one surface nozzle and the at least one back nozzle, The substrate processing apparatus further includes a control unit configured to control operations of the liquid processing unit and the supercritical drying unit to cause the substrate processing apparatus to perform the substrate processing method according to any one of claims 1 to 10 .

12. A computer-readable storage medium, wherein: A computer program is stored, and when the computer constituting a control unit of a substrate processing apparatus is executed, the computer controls the substrate processing apparatus to execute the substrate processing method according to any one of claims 1 to 10.

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