Wafer processing method and wafer processing device

Abstract

To provide a wafer processing method capable of reducing a possibility that a liquid is left in a hole when the hole is formed in a liquid film covering a top face of a wafer, and capable of reducing or weakening disturbance of an air current which is generated when widening the hole.SOLUTION: A wafer processing method includes: a liquid film formation step of covering an entire area of a top face of a wafer W with a liquid film; a hole formation step of forming an exposure hole HL, where a central part of the top face of the wafer W is exposed, in a central part of the liquid film by discharging a gas at a hole formation flow rate from a central discharge port 45c of a fluid nozzle 45, which is positioned at a central lower position that is a position at an upper side of the wafer, to a central part of the top face of the wafer W; and a hole enlargement step of expanding an outer edge HLe of the exposure hole HL to an outer periphery of the top face of the wafer W by discharging a gas at a hole enlargement flow rate, which is larger than the hole formation flow rate, from the central discharge port 45c of the fluid nozzle 45, which is positioned at a central upper position that is a position upper than the central lower position, to the central part of the top face of the wafer W.SELECTED DRAWING: Figure 5A-F

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus for processing a substrate. Examples of the substrate include semiconductor wafers, substrates for FPD (Flat Panel Display) such as liquid crystal display devices and organic EL (electroluminescence) display devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, substrates for solar cells, and the like.

Background Art

[0002] Patent Document 1 discloses discharging an inert gas from a first moving nozzle toward the upper surface of a substrate to form a hole in the center of a liquid film of an organic solvent and expand this hole. FIG. 9 of Patent Document 1 shows that the first moving nozzle is disposed at a position below the center both when forming the hole and when expanding the hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The gas discharged from the nozzle toward the upper surface of the substrate flows along the upper surface of the substrate after colliding with the upper surface of the substrate. However, if the nozzle is disposed close to the substrate and a large flow rate of gas is discharged from the nozzle, airflows other than the airflow parallel or substantially parallel to the upper surface of the substrate may increase or become stronger.

[0005] On the other hand, the gas discharged from the nozzle located above the substrate forms a columnar or linear air current extending from the nozzle to the upper surface of the substrate. The diameter of the air current increases as it moves away from the nozzle. When an air current with a large diameter collides with the liquid film on the substrate when forming a hole in the liquid film, liquid is likely to remain in the hole. To reduce or weaken the above-mentioned air current turbulence, if the nozzle is moved farther away from the substrate, the possibility that liquid remains in the hole when the hole is formed increases.

[0006] Therefore, one object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of reducing the possibility that liquid remains in a hole when forming a hole in a liquid film covering the upper surface of a substrate, and capable of reducing or weakening the air current turbulence generated when enlarging the hole.

Means for Solving the Problems

[0007] One embodiment of the present invention includes a liquid film forming step of covering the entire upper surface of the substrate with a liquid film that is a film of the processing liquid by discharging the processing liquid toward the upper surface of the horizontally held substrate, and a hole forming step of forming an exposed hole in which the central portion of the upper surface of the substrate is exposed in the central portion of the liquid film by discharging gas at a hole forming flow rate from a central discharge port of a fluid nozzle located at a central lower position above the substrate toward the central portion of the upper surface of the substrate, and a hole enlarging step of expanding the outer edge of the exposed hole to the outer periphery of the upper surface of the substrate by discharging gas at a hole enlarging flow rate larger than the hole forming flow rate from the central discharge port of the fluid nozzle located at a central upper position above the central lower position toward the central portion of the upper surface of the substrate.

[0008] In the above embodiment, at least one of the following features may be added to the substrate processing method.

[0009] The hole enlarging step includes a step of increasing the flow rate of the gas discharged from the central discharge port to the hole enlarging flow rate when the fluid nozzle is located at the central upper position.

[0010] The hole enlargement step includes increasing the flow rate of the gas discharged from the central discharge port to the hole enlargement flow rate while increasing the increase amount of the gas flow rate per unit time as time elapses when the fluid nozzle is located at the central upper position.

[0011] The substrate processing method further includes a radial airflow forming step of covering the upper surface of the substrate with gas discharged radially from an annular discharge port surrounding a vertical line passing through the central portion of the upper surface of the substrate after the exposed hole is formed.

[0012] The substrate processing method further includes a spin drying step of rotating the substrate around a vertical axis passing through the central portion of the upper surface of the substrate while discharging gas toward the central portion of the upper surface of the substrate from the central discharge port at a drying flow rate that is greater than the hole forming flow rate and less than the hole enlargement flow rate after the outer edge of the exposed hole has spread to the outer periphery of the upper surface of the substrate.

[0013] The substrate processing method further includes a radial airflow forming step of covering the upper surface of the substrate with gas discharged radially from an annular discharge port surrounding a vertical line passing through the central portion of the upper surface of the substrate while the spin drying step is being performed, and the drying flow rate is less than the flow rate of the gas discharged from the annular discharge port while the radial airflow forming step is being performed.

[0014] The substrate processing method further includes a liquid film floating step of forming a vapor layer of the processing liquid that floats the liquid film from the upper surface of the substrate between the liquid film and the upper surface of the substrate by heating the substrate before the exposed hole is formed.

[0015] Other embodiments of the present invention include a substrate holder that holds a substrate horizontally, a processing liquid nozzle that discharges a processing liquid toward the upper surface of the substrate held by the substrate holder to cover the entire upper surface of the substrate with a liquid film that is a film of the processing liquid, and a central discharge port that discharges gas at a hole forming flow rate toward the central portion of the upper surface of the substrate held by the substrate holder when located at a central lower position that is a position above the substrate. A fluid nozzle that forms an exposed hole in which the central portion of the upper surface of the substrate is exposed in the central portion of the liquid film, a nozzle actuator that raises the fluid nozzle from the central lower position to the central upper position, and a change in the flow rate of the gas discharged from the central discharge port of the fluid nozzle. By doing so, when the fluid nozzle is located at the central upper position, gas is discharged from the central discharge port toward the central portion of the upper surface of the substrate held by the substrate holder at a hole expansion flow rate that is larger than the hole forming flow rate, and an outer edge of the exposed hole is expanded to the outer periphery of the upper surface of the substrate. A flow rate adjustment valve is provided, and a substrate processing apparatus is provided. At least one of the above-described features regarding the substrate processing method may be added to the substrate processing apparatus.

Brief Description of the Drawings

[0016]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5A-F

Figure 6

Best Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] FIG. 1A is a schematic plan view showing the layout of a substrate processing apparatus 1 according to an embodiment of the present invention. FIG. 1B is a schematic side view of the substrate processing apparatus 1. The substrate processing apparatus 1 is a single-wafer type apparatus that processes disk-shaped substrates W such as semiconductor wafers one by one. The substrate processing apparatus 1 includes a load port LP that holds a carrier CA for accommodating the substrate W, a plurality of processing units 2 that process the substrate W conveyed from the carrier CA on the load port LP with a processing fluid such as a processing liquid or a processing gas, a transfer system TS that transfers the substrate W between the carrier CA on the load port LP and the plurality of processing units 2, an outer wall 1a that forms a sealed space accommodating the plurality of processing units 2 and the transfer system TS, and a control device 3 that controls the substrate processing apparatus 1.

[0019] The plurality of processing units 2 form a plurality of towers TW. FIG. 1A shows an example in which four towers TW are formed. As shown in FIG. 1B, the plurality of processing units 2 included in one tower TW are stacked vertically. As shown in FIG. 1A, the plurality of towers TW form two rows extending in the depth direction (the left-right direction of the paper surface of FIG. 1A) of the substrate processing apparatus 1 in plan view. In plan view, the two rows face each other via a transfer path TP.

[0020] The transfer system TS includes an index robot IR that transfers the substrate W between the carrier CA on the load port LP and the plurality of processing units 2, and a center robot CR that transfers the substrate W between the index robot IR and the plurality of processing units 2. The index robot IR is disposed between the load port LP and the center robot CR in plan view. The center robot CR is disposed on the transfer path TP.

[0021] The indexer robot IR includes one or more hands Hi that horizontally support the substrate W. The hand Hi is movable parallel to both the horizontal and vertical directions. The hand Hi is rotatable about a vertical straight line. The hand Hi can carry the substrate W into and out of the carrier CA on any load port LP and can transfer the substrate W with the center robot CR.

[0022] The center robot CR includes one or more hands Hc that horizontally support the substrate W. The hand Hc is movable parallel to both the horizontal and vertical directions. The hand Hc is rotatable about a vertical straight line. The hand Hc can transfer the substrate W with the indexer robot IR and can carry the substrate W into and out of any processing unit 2.

[0023] The control device 3 controls the electrical and electronic devices provided in the substrate processing apparatus 1. The control device 3 includes at least one computer. The computer includes a memory 3m that stores information such as programs, and a CPU 3c (central processing unit) that controls the substrate processing apparatus 1 according to the programs stored in the memory 3m. The control device 3 performs the conveyance and processing of the substrate W described below by controlling the substrate processing apparatus 1. In other words, the control device 3 is programmed to perform the conveyance and processing of the substrate W described below.

[0024] Next, the processing unit 2 will be described.

[0025] FIG. 2 is a schematic view of the inside of the processing unit 2 provided in the substrate processing apparatus 1 as seen horizontally. FIG. 3 is a schematic view showing a vertical cross section of the fluid nozzle 45 provided in the processing unit 2.

[0026] As shown in FIG. 2, the processing unit 2 includes a box-shaped chamber 4 having an internal space, a spin chuck 10 that rotates around a vertical rotation axis A1 passing through the central portion of the substrate W while horizontally holding one substrate W in the chamber 4, and a cylindrical processing cup 21 that surrounds the spin chuck 10 around the rotation axis A1.

[0027] The chamber 4 includes a box-shaped partition wall 5 provided with a loading / unloading port 5b through which the substrate W passes, and a door 7 that opens and closes the loading / unloading port 5b. The FFU 6 (Fan Filter Unit) is disposed above the air supply port 5a provided at the upper portion of the partition wall 5. The FFU 6 constantly supplies clean air (air filtered by a filter) into the chamber 4 from the air supply port 5a. The gas in the chamber 4 is discharged from the chamber 4 through an exhaust duct 8 connected to the bottom of the processing cup 21. Thereby, a downflow of clean air is constantly formed in the chamber 4. The flow rate of the exhaust gas discharged into the exhaust duct 8 is changed according to the opening degree of an exhaust valve 9 disposed in the exhaust duct 8.

[0028] The spin chuck 10 includes a disk-shaped spin base 12 held horizontally, a plurality of chuck pins 11 that horizontally hold the substrate W above the spin base 12, a spin shaft 13 extending downward from the central portion of the spin base 12, and a spin motor 14 that rotates the spin shaft 13 to rotate the spin base 12 and the plurality of chuck pins 11.

[0029] The spin chuck 10 is not limited to a clamping type chuck that brings the plurality of chuck pins 11 into contact with the end face of the substrate W, and may be a vacuum type chuck that horizontally holds the substrate W by adsorbing the back surface (lower surface) of the substrate W, which is a non-device forming surface, to the upper surface 12u of the spin base 12. When the spin chuck 10 is a clamping type chuck, the plurality of chuck pins 11 correspond to a substrate holder. When the spin chuck 10 is a vacuum type chuck, the spin base 12 corresponds to a substrate holder.

[0030] The processing cup 21 includes a plurality of guards 24 that receive the processing liquid discharged outward from the substrate W held by the spin chuck 10, a plurality of cups 23 that receive the processing liquid guided downward by the plurality of guards 24, and a cylindrical outer wall 22 that surrounds the plurality of guards 24 and the plurality of cups 23. FIG. 2 shows an example in which two guards 24 and two cups 23 are provided, and the outer cup 23 is integrated with the inner guard 24.

[0031] The guard 24 includes a cylindrical portion 25 that surrounds the spin chuck 10 and an annular ceiling portion 26 that extends obliquely upward from the upper end portion of the cylindrical portion 25 toward the rotation axis A1. The plurality of ceiling portions 26 overlap vertically, and the plurality of cylindrical portions 25 are arranged concentrically. The annular upper end of the ceiling portion 26 corresponds to the upper end 24u of the guard 24 that surrounds the substrate W and the spin base 12 in plan view. The plurality of cups 23 are respectively disposed below the plurality of cylindrical portions 25. The cup 23 forms an annular groove for receiving the processing liquid guided downward by the guard 24.

[0032] The processing unit 2 includes a guard lifting actuator 27 that individually raises and lowers the plurality of guards 24. The guard lifting actuator 27 positions the guard 24 at an arbitrary position within the range from the upper position to the lower position. FIG. 2 shows a state in which two guards 24 are disposed at the lower position. The upper position is a position where the upper end 24u of the guard 24 is disposed above the holding position where the substrate W held by the spin chuck 10 is disposed. The lower position is a position where the upper end 24u of the guard 24 is disposed below the holding position.

[0033] An actuator is a device that converts driving energy representing electrical, fluid, magnetic, thermal, or chemical energy into mechanical work, that is, the movement of a physical object. Actuators include electric motors (rotary motors), linear motors, air cylinders, and other devices. When the movement of the actuator is different from the movement of the object, a motion converter that converts the movement of the actuator into linear motion or rotation may be provided. For example, when the actuator is an electric motor and the object is to be moved linearly, the rotation of the electric motor may be converted into linear motion by a motion converter such as a ball screw and a ball nut.

[0034] The processing unit 2 includes a chemical solution nozzle 31 that discharges a chemical solution toward the upper surface of the substrate W held by the spin chuck 10, and a rinse solution nozzle 33 that discharges a rinse solution toward the upper surface of the substrate W held by the spin chuck 10. FIG. 2 shows an example in which the chemical solution is HF (hydrofluoric acid) and the rinse solution is DIW (pure water).

[0035] The chemical solution nozzle 31 is connected to a chemical solution pipe 32p that guides the chemical solution. When the chemical solution valve 32v attached to the chemical solution pipe 32p is opened, the discharge port of the chemical solution nozzle 31 continuously discharges the chemical solution downward. The chemical solution may be a liquid containing at least one of sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, aqueous ammonia, hydrogen peroxide water, organic acids (for example, citric acid, oxalic acid, etc.), organic alkalis (for example, TMAH: tetramethylammonium hydroxide, etc.), surfactants, and corrosion inhibitors, or may be other liquids.

[0036] Although not shown, the chemical solution valve 32v includes a valve body provided with an annular valve seat through which the chemical solution passes, a valve element movable with respect to the valve seat, and an actuator that moves the valve element between a closed position where the valve element contacts the valve seat and an open position where the valve element is separated from the valve seat. The same applies to other valves. The actuator may be a pneumatic actuator or an electric actuator, or may be other actuators. The control device 3 opens and closes the chemical solution valve 32v and the like by controlling the actuator.

[0037] The rinse liquid nozzle 33 is connected to a rinse liquid pipe 34p that guides the rinse liquid. When the rinse liquid valve 34v attached to the rinse liquid pipe 34p is opened, the discharge port of the rinse liquid nozzle 33 continuously discharges the rinse liquid downward. The rinse liquid may be any one of pure water (deionized water: DIW (Deionized Water)), carbonated water, electrolyzed ion water, hydrogen water, ozone water, and hydrochloric acid water with a dilution concentration (for example, about 10 to 100 ppm), or may be a liquid other than these.

[0038] The chemical liquid nozzle 31 may be a scan nozzle that moves the collision position of the chemical liquid with respect to the substrate W within the upper surface of the substrate W, or may be a fixed nozzle that cannot move the collision position of the chemical liquid with respect to the substrate W. The same applies to other nozzles. FIG. 2 shows an example in which the chemical liquid nozzle 31 and the rinse liquid nozzle 33 are scan nozzles.

[0039] The chemical liquid nozzle 31 is connected to a nozzle actuator 32a that moves the chemical liquid nozzle 31 in at least one of the vertical direction and the horizontal direction. The rinse liquid nozzle 33 is connected to a nozzle actuator 34a that moves the rinse liquid nozzle 33 in at least one of the vertical direction and the horizontal direction. The nozzle actuator 32a horizontally moves the chemical liquid nozzle 31 between a processing position where the chemical liquid discharged from the chemical liquid nozzle 31 is supplied to the upper surface of the substrate W and a standby position where the chemical liquid nozzle 31 is located around the processing cup 21 in plan view. The same applies to the nozzle actuator 34a.

[0040] The processing unit 2 includes a fluid nozzle 45 that discharges a processing fluid above the substrate W held by the spin chuck 10. The fluid nozzle 45 includes a solvent discharge port 45d that discharges an organic solvent toward the upper surface of the substrate W held by the spin chuck 10, a central discharge port 45c that discharges a gas toward the upper surface of the substrate W, and at least one annular discharge port that radially discharges a gas above the substrate W. FIG. 2 shows an example in which two annular discharge ports, that is, a first annular discharge port 45a and a second annular discharge port 45b are provided.

[0041] As shown in FIG. 3, the fluid nozzle 45 includes a solvent nozzle 45D that forms the solvent discharge port 45d, a first gas nozzle 45C that forms the central discharge port 45c, and a second gas nozzle 45A that forms the first annular discharge port 45a and the second annular discharge port 45b. FIG. 3 shows an example in which the second gas nozzle 45A is an integrated single member, and each of the solvent nozzle 45D and the first gas nozzle 45C is a member different from the second gas nozzle 45A held by the second gas nozzle 45A. The second gas nozzle 45A may be composed of a plurality of members fixed to each other. The solvent nozzle 45D may be integral with at least a part of the second gas nozzle 45A. The same applies to the first gas nozzle 45C.

[0042] The fluid nozzle 45 includes a cylindrical outer peripheral surface 45o that surrounds the vertical center line L1 of the fluid nozzle 45, an annular horizontal lower surface 45L that extends inward from the lower end of the outer peripheral surface 45o of the fluid nozzle 45, and a recess 45r that is recessed upward from the lower surface 45L of the fluid nozzle 45 inside the lower surface 45L of the fluid nozzle 45. The outer peripheral surface 45o of the fluid nozzle 45 corresponds to the outer peripheral surface of the second gas nozzle 45A. The lower surface 45L of the fluid nozzle 45 corresponds to the lower surface of the second gas nozzle 45A. The solvent discharge port 45d and the central discharge port 45c are disposed in the recess 45r. The first annular discharge port 45a and the second annular discharge port 45b open on the outer peripheral surface 45o of the fluid nozzle 45. The outer diameter of the fluid nozzle 45, that is, the diameter of the outer peripheral surface 45o of the fluid nozzle 45 is smaller than the diameter of the substrate W.

[0043] The solvent nozzle 45D and the first gas nozzle 45C extend vertically along the center line L1 of the fluid nozzle 45. The solvent nozzle 45D and the first gas nozzle 45C protrude upward from the second gas nozzle 45A. The lower end of the solvent nozzle 45D and the lower end of the first gas nozzle 45C are disposed in the recess 45r. The solvent discharge port 45d opens at the lower end of the solvent nozzle 45D. The central discharge port 45c opens at the lower end of the first gas nozzle 45C. At least a part of the solvent discharge port 45d may be disposed at the same height as the central discharge port 45c, or may be disposed above or below the central discharge port 45c. FIG. 3 shows an example in which the solvent discharge port 45d and the central discharge port 45c are disposed at the same height as each other.

[0044] The solvent nozzle 45D is connected to a solvent pipe 49p to which a solvent valve 49v is attached. When the solvent valve 49v is opened, the organic solvent is supplied from the solvent pipe 49p to the solvent nozzle 45D, and is continuously discharged downward from the solvent discharge port 45d of the solvent nozzle 45D. The organic solvent discharged from the solvent discharge port 45d is a liquid of the organic solvent. FIG. 3 shows an example in which the organic solvent is IPA (isopropyl alcohol). The organic solvent discharged from the solvent discharge port 45d may be an alcohol other than IPA, or may be a fluorinated organic solvent such as HFE (hydrofluoroether).

[0045] The first gas nozzle 45C is connected to a gas pipe 48p to which a gas valve 48v and a flow rate adjustment valve 48f are attached. When the gas valve 48v is opened, gas is supplied from the gas pipe 48p to the first gas nozzle 45C at a flow rate corresponding to the opening degree of the flow rate adjustment valve 48f, and is continuously discharged downward from the central discharge port 45c of the first gas nozzle 45C. When the control device 3 (see FIG. 2) changes the opening degree of the flow rate adjustment valve 48f, the flow rate of the gas discharged from the central discharge port 45c increases or decreases. FIG. 3 shows an example in which nitrogen gas is discharged from the central discharge port 45c. The gas discharged from the central discharge port 45c may be an inert gas other than nitrogen gas, or may be a gas other than an inert gas such as clean air or dry air.

[0046] The first annular discharge port 45a and the second annular discharge port 45b are annular slits that are continuous in the circumferential direction of the fluid nozzle 45 over the entire circumference of the fluid nozzle 45. The second annular discharge port 45b is disposed above the first annular discharge port 45a. When the fluid nozzle 45 is disposed at the central upper position and the central lower position described later, the center line L1 of the fluid nozzle 45 is disposed on the rotation axis A1 of the substrate W. The first annular discharge port 45a and the second annular discharge port 45b surround the rotation axis A1 of the substrate W. The diameters of the first annular discharge port 45a and the second annular discharge port 45b are smaller than the outer diameter of the substrate W. The diameters of the first annular discharge port 45a and the second annular discharge port 45b may be equal to each other or different from each other.

[0047] At least a part of the first annular discharge port 45a may be disposed at the same height as the solvent discharge port 45d, or may be disposed above or below the solvent discharge port 45d. At least a part of the first annular discharge port 45a may be disposed at the same height as the central discharge port 45c, or may be disposed above or below the central discharge port 45c. The same applies to the second annular discharge port 45b. FIG. 3 shows an example in which at least a part of the first annular discharge port 45a is disposed below the solvent discharge port 45d and the central discharge port 45c, and the entire second annular discharge port 45b is disposed above the solvent discharge port 45d and the central discharge port 45c.

[0048] The first annular discharge port 45a is connected to a first gas pipe 46p to which a first gas valve 46v and a first flow rate adjustment valve 46f are attached. The second annular discharge port 45b is connected to a second gas pipe 47p to which a second gas valve 47v and a second flow rate adjustment valve 47f are attached. When the first gas valve 46v is opened, gas is supplied from the first gas pipe 46p to the first annular discharge port 45a at a flow rate corresponding to the opening degree of the first flow rate adjustment valve 46f and is discharged from the first annular discharge port 45a. Similarly, when the second gas valve 47v is opened, gas is supplied from the second gas pipe 47p to the second annular discharge port 45b at a flow rate corresponding to the opening degree of the second flow rate adjustment valve 47f and is discharged from the second annular discharge port 45b. FIG. 3 shows an example in which nitrogen gas is discharged from the first annular discharge port 45a and the second annular discharge port 45b.

[0049] When the first annular discharge port 45a discharges gas, an air flow that radially spreads from the first annular discharge port 45a is formed. Similarly, when the second annular discharge port 45b discharges gas, an air flow that radially spreads from the second annular discharge port 45b is formed. Most of the gas discharged from the first annular discharge port 45a passes under the gas discharged from the second annular discharge port 45b. Therefore, when both the first gas valve 46v and the second gas valve 47v are opened, a plurality of vertically overlapping air flows are formed around the fluid nozzle 45.

[0050] FIG. 3 shows an example in which both the first annular discharge port 45a and the second annular discharge port 45b discharge gas radially in the horizontal direction. At least one of the first annular discharge port 45a and the second annular discharge port 45b may discharge gas radially in an obliquely downward direction. In this case, when the fluid nozzle 45 is disposed at any position within the range from the central upper position to the central lower position, at least one of the first annular discharge port 45a and the second annular discharge port 45b may discharge gas radially in an obliquely downward direction toward an annular region within the upper surface of the substrate W surrounding the center of the substrate W.

[0051] As shown in FIG. 3, the fluid nozzle 45 includes a first inlet 50a that opens on the surface of the fluid nozzle 45, and a first gas passage 51a that guides gas from the first inlet 50a to the first annular discharge port 45a. The fluid nozzle 45 further includes a second inlet 50b that opens on the surface of the fluid nozzle 45, and a second gas passage 51b that guides gas from the second inlet 50b to the second annular discharge port 45b. The gas in the first gas pipe 46p flows into the first gas passage 51a through the first inlet 50a, and is guided to the first annular discharge port 45a by the first gas passage 51a. Similarly, the gas in the second gas pipe 47p flows into the second gas passage 51b through the second inlet 50b, and is guided to the second annular discharge port 45b by the second gas passage 51b.

[0052] The first inlet 50a and the second inlet 50b are disposed above the first annular discharge port 45a and the second annular discharge port 45b. The first gas passage 51a extends from the first inlet 50a to the first annular discharge port 45a, and the second gas passage 51b extends from the second inlet 50b to the second annular discharge port 45b. As shown in FIG. 3, the first gas passage 51a and the second gas passage 51b are cylindrical and surround the vertical center line L1 of the fluid nozzle 45. The first gas passage 51a and the second gas passage 51b are arranged concentrically. The first gas passage 51a is surrounded by the second gas passage 51b.

[0053] The processing unit 2 includes a nozzle arm 52 that holds the fluid nozzle 45, and a nozzle actuator 52a that moves the nozzle arm 52 to move the fluid nozzle 45 in the vertical and horizontal directions. The nozzle arm 52 is connected to the fluid nozzle 45 at a position above the first annular discharge port 45a and the second annular discharge port 45b. When the nozzle actuator 52a moves the second gas nozzle 45A, the solvent nozzle 45D and the second gas nozzle 45A also move.

[0054] The nozzle actuator 52a horizontally moves the fluid nozzle 45 between the central upper position (the position shown in FIG. 2) and the standby position (the position shown by the two-dot chain line in FIG. 2). The nozzle actuator 52a further vertically moves the fluid nozzle 45 between the central upper position and the central lower position (the position shown in FIG. 3). The standby position is the position where the fluid nozzle 45 is located around the processing cup 21 in plan view. The central upper position and the central lower position are the positions where the fluid nozzle 45 overlaps the central portion of the substrate W in plan view. The central upper position is above the central lower position. When the fluid nozzle 45 is disposed at the central lower position, the vertical distance from the upper surface of the substrate W to the lower surface 45L of the fluid nozzle 45 may be smaller than the radius of the fluid nozzle 45 or may be equal to or greater than the radius.

[0055] Hereinafter, the central upper position and the central lower position may be collectively referred to as the central position. When the fluid nozzle 45 is disposed at the central position, the fluid nozzle 45 overlaps the central portion of the upper surface of the substrate W in plan view. However, since the fluid nozzle 45 is smaller than the substrate W in plan view, the respective portions of the upper surface of the substrate W other than the central portion do not overlap the fluid nozzle 45 in plan view. When at least one of the first gas valve 46v and the second gas valve 47v is opened while the fluid nozzle 45 is disposed at the central position, an air flow spreading radially from the fluid nozzle 45 flows above the respective portions of the upper surface of the substrate W other than the central portion. Thereby, the entire area of the upper surface of the substrate W is protected by the fluid nozzle 45 and the air flow.

[0056] As shown in FIG. 2, the processing unit 2 includes a hot plate 61 which is an example of a heater for heating the substrate W held by the spin chuck 10. The hot plate 61 is disposed between the substrate W supported by the plurality of chuck pins 11 and the spin base 12. The hot plate 61 is vertically movable in parallel between an upper position and a lower position (the position shown in FIG. 2) above the spin base 12. The substrate W is transferred between the plurality of chuck pins 11 and the hot plate 61 by the ascent or descent of the hot plate 61. The hot plate 61 is an example of a substrate holder.

[0057] The hot plate 61 includes a heating element 62 that generates Joule heat when energized, and an outer case 63 that houses the heating element 62. The outer case 63 is disposed between a substrate W supported by a plurality of chuck pins 11 and a spin base 12. The temperature of the heating element 62 is changed by the control device 3. When the control device 3 causes the heating element 62 to generate heat, the entire substrate W is uniformly heated.

[0058] The outer case 63 of the hot plate 61 includes a disk-shaped base portion 63b disposed below the substrate W supported by a plurality of chuck pins 11, and a plurality of hemispherical protrusions 63p protruding upward from the upper surface of the base portion 63b. The upper surface of the base portion 63b is parallel to the lower surface of the substrate W and has an outer diameter smaller than the diameter of the substrate W. The plurality of protrusions 63p contact the lower surface of the substrate W at positions spaced upward from the upper surface of the base portion 63b. The plurality of protrusions 63p are arranged at a plurality of positions within the upper surface of the base portion 63b so that the substrate W is horizontally supported. The substrate W is horizontally supported in a state where the lower surface of the substrate W is spaced upward from the upper surface of the base portion 63b.

[0059] The hot plate 61 is horizontally supported by a support shaft 64 extending downward from the central portion of the hot plate 61. The plurality of chuck pins 11 are arranged around the hot plate 61. The center line of the hot plate 61 is disposed on the rotation axis A1 of the substrate W. Even when the spin chuck 10 rotates, the hot plate 61 does not rotate. The outer diameter of the hot plate 61 is smaller than the diameter of the substrate W.

[0060] The hot plate 61 is connected to a plate lifting actuator 64a via the support shaft 64. The plate lifting actuator 64a vertically raises and lowers the hot plate 61 with respect to the spin base 12 between an upper position (the position shown in FIG. 5A) and a lower position (the position shown in FIG. 2). The upper position is a contact position where the hot plate 61 contacts the lower surface of the substrate W. The lower position is a proximity position where the hot plate 61 is disposed between the lower surface of the substrate W and the upper surface 12u of the spin base 12 in a state where the hot plate 61 is separated from the substrate W.

[0061] The plate lifting actuator 64a positions the hot plate 61 at an arbitrary position within the range from the upper position to the lower position. The substrate W is supported by a plurality of chuck pins 11. When the hot plate 61 rises to the upper position with all the chuck pins 11 arranged in the open position, a plurality of protrusions 63p of the hot plate 61 come into contact with the lower surface of the substrate W, and the substrate W is lifted by the hot plate 61. As a result, the substrate W moves upward away from the plurality of chuck pins 11.

[0062] When the substrate W is supported by the hot plate 61 positioned at the upper position and all the chuck pins 11 are arranged in the open position, and the hot plate 61 descends, before the hot plate 61 reaches the lower position, the substrate W on the hot plate 61 is placed on the plurality of chuck pins 11, and the hot plate 61 moves downward away from the substrate W. In this way, the substrate W is transferred between the plurality of chuck pins 11 and the hot plate 61.

[0063] Next, an example of the processing of the substrate W performed by the substrate processing apparatus 1 will be described.

[0064] FIG. 4 is a process diagram for explaining an example of the processing of the substrate W performed by the substrate processing apparatus 1. FIGS. 5A, 5B, 5C, 5D, 5E, and 5F are schematic cross-sectional views showing the state of the substrate W when an example of the processing shown in FIG. 4 is being performed. The region hatched in FIGS. 5A to 5D represents the liquid film of IPA. Hereinafter, reference will be made to FIGS. 2 and 4. Appropriate reference will be made to FIGS. 5A to 5F.

[0065] The substrate W to be processed is, for example, a semiconductor wafer such as a silicon wafer. The surface of the substrate W corresponds to a device formation surface on which devices such as transistors and capacitors are formed. The substrate W may be a substrate W having a pattern PA (see FIG. 5A) formed on the surface of the substrate W, or a substrate W having no pattern PA formed on the surface of the substrate W. In the latter case, the pattern PA may be formed in the chemical solution supply step described later.

[0066] When processing the substrate W by the substrate processing apparatus 1, a loading process (step S1 in FIG. 4) of loading the substrate W into the chamber 4 is performed.

[0067] Specifically, with all the guards 24 in the lower position and all the scan nozzles in the standby position, the center robot CR (see FIG. 1A) enters the chamber 4 with the hand Hc while supporting the substrate W with the hand Hc. The center robot CR places the substrate W on the hand Hc with the surface of the substrate W facing upward on the plurality of chuck pins 11. Thereafter, the plurality of chuck pins 11 are pressed against the end surface of the substrate W, and the substrate W is held. After the center robot CR places the substrate W on the spin chuck 10, the hand Hc is retracted from the inside of the chamber 4.

[0068] After the substrate W is held by the spin chuck 10, a chemical solution supply process (step S2 in FIG. 4) of forming a liquid film of the chemical solution covering the entire upper surface of the substrate W by supplying the chemical solution to the upper surface of the substrate W is performed.

[0069] Specifically, the nozzle actuator 32a moves the chemical solution nozzle 31 from the standby position to the processing position. The guard lifting actuator 27 raises at least one guard 24 from the lower position to the upper position. The spin motor 14 starts the rotation of the substrate W. Thereby, the substrate W rotates at the chemical solution supply rate. The raising of the guard 24 may be started simultaneously with the chemical solution nozzle 31 reaching the processing position, or may be started before or after reaching the processing position. The same applies to the timing of starting the rotation of the substrate W.

[0070] The chemical liquid nozzle 31 is located at the processing position, at least one guard 24 is located at the upper position, and with the substrate W rotating at the chemical liquid supply speed, the chemical liquid valve 32v is opened, and the chemical liquid nozzle 31 starts discharging the chemical liquid. The chemical liquid discharged from the chemical liquid nozzle 31 collides with the upper surface of the substrate W rotating at the chemical liquid supply speed and then flows outward along the upper surface of the substrate W. Thereby, the chemical liquid is supplied to the entire area of the upper surface of the substrate W, and a liquid film of the chemical liquid covering the entire area of the upper surface of the substrate W is formed.

[0071] When a predetermined time has elapsed since the chemical liquid valve 32v was opened, the chemical liquid valve 32v is closed, and the discharge of the chemical liquid is stopped. Then, the nozzle actuator 32a moves the chemical liquid nozzle 31 to the standby position. When the chemical liquid nozzle 31 is discharging the chemical liquid, the nozzle actuator 32a may move the collision position so that the collision position of the chemical liquid with the upper surface of the substrate W passes through the central portion and the outer peripheral portion, or may keep the collision position stationary at the central portion. Whether to move the collision position or not is the same for the processing liquid supplied to the upper surface of the substrate W after the chemical liquid.

[0072] After supplying the chemical liquid to the substrate W, a rinse liquid supply step (step S3 in FIG. 4) of washing away the chemical liquid on the substrate W with pure water is performed by supplying pure water, which is an example of the rinse liquid, to the upper surface of the substrate W.

[0073] Specifically, with at least one guard 24 located at the upper position, the nozzle actuator 34a moves the rinse liquid nozzle 33 from the standby position to the processing position. Then, the rinse liquid valve 34v is opened, and the rinse liquid nozzle 33 starts discharging the rinse liquid. Before the discharge of pure water starts, the guard lifting actuator 27 may vertically move at least one guard 24 to switch the guard 24 for receiving the liquid discharged from the substrate W.

[0074] The pure water discharged from the rinse liquid nozzle 33 impinges on the upper surface of the substrate W rotating at the rinse liquid supply rate and then flows outward along the upper surface of the substrate W. The rinse liquid supply rate may be equal to or different from the chemical liquid supply rate. The chemical liquid on the substrate W is replaced with the pure water discharged from the rinse liquid nozzle 33. Thereby, a liquid film of pure water covering the entire area of the upper surface of the substrate W is formed. When a predetermined time has elapsed since the rinse liquid valve 34v was opened, the rinse liquid valve 34v is closed and the discharge of the rinse liquid is stopped. Thereafter, the nozzle actuator 34a moves the rinse liquid nozzle 33 to the standby position.

[0075] After supplying pure water to the substrate W, an organic solvent supply step (step S4 in FIG. 4) is performed in which IPA, which is an example of an organic solvent, is supplied to the upper surface of the substrate W to replace the liquid film of the rinse liquid on the substrate W with a liquid film of IPA.

[0076] Specifically, with at least one guard 24 in the upper position, the nozzle actuator 52a moves the fluid nozzle 45 from the standby position to the central position. Thereafter, the solvent valve 49v is opened and the solvent discharge port 45d of the fluid nozzle 45 starts discharging IPA. Before the discharge of IPA is started, the guard lift actuator 27 may vertically move at least one guard 24 in order to switch the guard 24 that receives the liquid discharged from the substrate W.

[0077] The IPA discharged from the solvent discharge port 45d of the fluid nozzle 45 impinges on the upper surface of the substrate W rotating at the solvent supply rate and then flows outward along the upper surface of the substrate W. The solvent supply rate may be equal to or different from the rinse liquid supply rate. The pure water on the substrate W is replaced with the IPA discharged from the solvent discharge port 45d. Thereby, a liquid film of IPA covering the entire area of the upper surface of the substrate W is formed (see FIG. 5A). When a predetermined time has elapsed since the solvent valve 49v was opened, the solvent valve 49v is closed and the discharge of IPA is stopped.

[0078] From the start of the organic solvent supply process until the completion of the spin-drying process described later, the fluid nozzle 45 is arranged at the central position. Whether the fluid nozzle 45 stops at the upper central position or the lower central position and at what timing it moves between the upper central position and the lower central position will be described later.

[0079] After replacing the pure water liquid film with the IPA liquid film, a paddle process may be performed to stagnate IPA on the upper surface of the substrate W while maintaining the state where the entire upper surface of the substrate W is covered with the IPA liquid film.

[0080] Specifically, with the entire upper surface of the substrate W covered with the IPA liquid film, the rotation speed of the substrate W may be decreased to the paddle speed (for example, a speed of more than 0 and 50 rpm or less) or to zero. In this way, IPA does not move or hardly moves relative to the upper surface of the substrate W and stagnates on the upper surface of the substrate W. When the rotation speed of the substrate W is decreased to zero, the hot plate 61 may be raised to the upper position with the holding of the substrate W by the plurality of chuck pins 11 released, so that the substrate W is supported by the hot plate 61. When the substrate W is rotating or stationary at the paddle speed, the supply of new IPA to the upper surface of the substrate W may be continued or stopped.

[0081] After supplying IPA to the substrate W, a liquid film floating process (step S5 in FIG. 4) is performed to form a vapor layer VL of IPA (see FIG. 5B) that floats the IPA liquid film between the IPA liquid film and the upper surface of the substrate W.

[0082] Specifically, with the substrate W disposed above the hot plate 61, the hot plate 61 generates heat to start heating the substrate W. The heat generation of the hot plate 61 may start before or after the IPA is supplied to the substrate W, or may start simultaneously with the supply of the IPA to the substrate W. The hot plate 61 may heat the substrate W while being in contact with the lower surface of the substrate W, or may heat the substrate W while being separated from the lower surface of the substrate W. The temperature of the substrate W may be changed by changing the temperature of the hot plate 61, or may be changed by changing the distance between the substrate W and the hot plate 61.

[0083] When the hot plate 61 heats the substrate W while being in contact with the lower surface of the substrate W, the substrate W remains stationary on the hot plate 61. When the hot plate 61 heats the substrate W while being separated from the lower surface of the substrate W, the spin chuck 10 rotates the substrate W at a liquid discharge rate. The liquid discharge rate is greater than the paddle speed. The liquid discharge rate may be equal to or different from the solvent supply rate.

[0084] When the supply of power to the hot plate 61 is started, the entire or substantially the entire upper surface of the hot plate 61 generates heat. Therefore, the substrate W can be heated uniformly as compared with the case where a heating fluid such as warm water is discharged toward the central portion of the lower surface of the substrate W. The IPA on the upper surface of the substrate W is heated by the hot plate 61 via the substrate W. If it is higher than room temperature (for example, 20 to 30 °C), the temperature of the hot plate 61 when heating the substrate W may be any value. The temperature of the hot plate 61 may be equal to or different from the boiling point of the liquid (IPA in this example) on the substrate W.

[0085] When the temperature of the upper surface of the substrate W (including the surface of the pattern PA when the pattern PA is formed) is equal to or higher than the boiling point of IPA, IPA vaporizes at the interface between IPA and the substrate W, and a large number of small bubbles are generated at the interface between IPA and the substrate W. When IPA vaporizes at every location at the interface between IPA and the substrate W, a vapor layer VL containing IPA vapor (see FIG. 5B) is formed between IPA and the substrate W. As a result, the liquid film of IPA separates from the upper surface of the substrate W, and the liquid film of IPA floats from the upper surface of the substrate W (the upper surface of the pattern PA when the pattern PA is formed). At this time, the frictional resistance applied from the substrate W to the liquid film of IPA can be regarded as being almost zero.

[0086] After floating the liquid film of IPA from the upper surface of the substrate W, a liquid discharging step of discharging the liquid film of IPA from the upper surface of the substrate W is performed. The liquid discharging step includes a hole forming step (step S6 in FIG. 4) of forming an exposure hole HL for exposing the central portion of the upper surface of the substrate W from the liquid film of IPA at the central portion of the liquid film of IPA, and a hole enlarging step (step S7 in FIG. 4) of expanding the outer edge HLe (see FIG. 5D) of the exposure hole HL to the outer periphery of the upper surface of the substrate W.

[0087] When forming the exposure hole HL, the fluid nozzle 45 is located at the central position, and with at least one guard 24 located at the upper position, the gas valve 48v is opened, and the discharge of the inert gas is started from the central discharge port 45c of the fluid nozzle 45. The temperature of the inert gas discharged from the central discharge port 45c may be room temperature or may exceed room temperature. The inert gas discharged from the central discharge port 45c collides with the liquid film of IPA at the central portion of the upper surface of the substrate W, and then flows outward in all directions along the surface of the liquid film of IPA. As a result, the thickness of the central portion of the liquid film of IPA decreases, and a substantially circular exposure hole HL is formed at the central portion of the liquid film of IPA (see FIG. 5C). Further, a force for moving IPA outward is applied from the inert gas to the IPA on the substrate W, and IPA flows outward along the upper surface of the substrate W.

[0088] When the exposure hole HL is formed, the liquid film of IPA changes from a substantially circular shape to a ring shape concentric with the outer periphery of the substrate W. IPA flows down from the outer periphery of the upper surface of the substrate W. Along with this, the inner diameter of the ring-shaped liquid film of IPA continuously increases to a value equal to the outer diameter of the upper surface of the substrate W. In other words, the outer edge HLe of the exposure hole HL spreads to the outer periphery of the upper surface of the substrate W without stopping while remaining substantially circular and concentric with the outer periphery of the substrate W (see Fig. 5D). At this time, all of the IPA on the substrate W is discharged from the upper surface of the substrate W without splitting while remaining connected. As a result, droplets of visible size disappear from the upper surface of the substrate W, and the entire area of the upper surface of the substrate W is exposed (see Fig. 5E).

[0089] After all of the liquid film of IPA has disappeared from the upper surface of the substrate W, a spin-drying process (step S8 in Fig. 4) for drying the substrate W by high-speed rotation of the substrate W is performed.

[0090] Specifically, when the hot plate 61 supports the lower surface of the substrate W, the substrate W is transferred from the hot plate 61 to the plurality of chuck pins 11, and the plurality of chuck pins 11 hold the substrate W. In this state, the spin chuck 10 rotates the substrate W at the drying speed (see Fig. 5F). The drying speed may be equal to or different from the solvent supply speed. Even if droplets of invisible size remain on the upper surface of the substrate W, such droplets evaporate while the substrate W is rotating at the drying speed. As a result, the substrate W dries. When a predetermined time has elapsed since the start of the high-speed rotation of the substrate W, the spin chuck 10 stops rotating. As a result, the rotation of the substrate W is stopped. During at least a part of the period in which the substrate W is rotating at the drying speed, the hot plate 61 may generate heat to promote the evaporation of the droplets.

[0091] The central discharge port 45c of the fluid nozzle 45 may stop discharging the inert gas before starting the high-speed rotation of the substrate W, that is, before starting the spin-dry process, or may continue discharging the inert gas until after starting the high-speed rotation of the substrate W. In the latter case, the central discharge port 45c may stop discharging the inert gas simultaneously with the stop of the rotation of the substrate W, or may stop discharging the inert gas before or after the stop of the rotation of the substrate W.

[0092] The first annular discharge port 45a and the second annular discharge port 45b of the fluid nozzle 45 may start discharging the inert gas before starting the high-speed rotation of the substrate W, or may start discharging the inert gas after starting the high-speed rotation of the substrate W. In the former case, the first annular discharge port 45a and the second annular discharge port 45b may start discharging the inert gas simultaneously with the start of discharging the inert gas from the central discharge port 45c of the fluid nozzle 45, or may start discharging the inert gas before or after the central discharge port 45c starts discharging the inert gas.

[0093] When discharging the inert gas from the central discharge port 45c of the fluid nozzle 45 while rotating the substrate W at the drying speed, close the gas valve 48v simultaneously with, before, or after the stop of the rotation of the substrate W. Thereby, the central discharge port 45c stops discharging the inert gas. When discharging the inert gas from the first annular discharge port 45a and the second annular discharge port 45b while rotating the substrate W at the drying speed, close the first gas valve 46v and the second gas valve 47v simultaneously with, before, or after the stop of the rotation of the substrate W. Thereby, the first annular discharge port 45a and the second annular discharge port 45b stop discharging the inert gas. The nozzle actuator 52a moves the fluid nozzle 45 from the central position to the standby position after the rotation of the substrate W stops, with the central discharge port 45c, the first annular discharge port 45a, and the second annular discharge port 45b not discharging the inert gas.

[0094] After drying the substrate W, perform a carry-out process (step S9 in FIG. 4) of carrying out the substrate W from the chamber 4.

[0095] Specifically, the guard lifting actuator 27 lowers all the guards 24 to the lower position. After that, the center robot CR causes the hand Hc to enter the chamber 4. After the plurality of chuck pins 11 release the holding of the substrate W, the center robot CR supports the substrate W on the spin chuck 10 with the hand Hc. Then, while supporting the substrate W with the hand Hc, the center robot CR retracts the hand Hc from inside the chamber 4. Thereby, the processed substrate W is carried out of the chamber 4.

[0096] Next, an example of the process from forming the exposure holes HL in the liquid film to drying the substrate W will be described.

[0097] FIG. 6 is a time chart for explaining an example of the process from forming the exposure holes HL in the liquid film to drying the substrate W. Before starting the hole forming step shown in FIG. 4 (before time T1), the fluid nozzle 45 is arranged at the central upper position, and the central discharge port 45c, the first annular discharge port 45a, and the second annular discharge port 45b of the fluid nozzle 45 are not discharging inert gas. The substrate W is supported by the hot plate 61 located at the upper position, and the hot plate 61 is maintained at a constant heating temperature exceeding room temperature. The liquid film of IPA covers the entire upper surface of the substrate W and is supported on the upper surface of the substrate W via the vapor layer VL (see FIG. 5B).

[0098] When starting the hole forming step shown in FIG. 4, at time T1, the fluid nozzle 45 is lowered from the central upper position to the central lower position, and the discharge of inert gas is started from the central discharge port 45c of the fluid nozzle 45. FIG. 6 shows an example in which the central discharge port 45c starts discharging inert gas simultaneously when the fluid nozzle 45 reaches the central lower position. The central discharge port 45c may start discharging inert gas after the fluid nozzle 45 reaches the central lower position. After starting the discharge of inert gas, the central discharge port 45c continues to discharge inert gas at the hole forming flow rate. During this time, the exposure holes HL are formed in the liquid film of IPA (see FIG. 5C).

[0099] After the exposure hole HL is formed in the liquid film of IPA, at time T2, the fluid nozzle 45 is raised from the central lower position to the central upper position, and the flow rate of the inert gas discharged from the central discharge port 45c of the fluid nozzle 45 (hereinafter also referred to as "central gas flow rate") is increased. FIG. 6 shows an example in which the central gas flow rate is increased simultaneously with the fluid nozzle 45 reaching the central upper position. After the fluid nozzle 45 reaches the central upper position, the central gas flow rate may be increased.

[0100] The central gas flow rate (the flow rate of the inert gas discharged from the central discharge port 45c of the fluid nozzle 45) increases stepwise or continuously from the hole formation flow rate to the hole expansion flow rate without decreasing. FIG. 6 shows an example in which the flow rate of the inert gas increases stepwise. In this example, the hole formation flow rate is 1.9 L / min, the hole expansion flow rate is 70 L / min, the central discharge port 45c is circular with a diameter of 2 mm, and the diameter of the substrate W is 300 mm. The period during which the central discharge port 45c continuously discharges gas at the hole formation flow rate (the period from time T1 to time T2) is 1 second. This period is shorter than the period until the central gas flow rate increases from the hole formation flow rate to the hole expansion flow rate. The hole expansion flow rate and the like are not limited to these values.

[0101] The hole formation flow rate is the flow rate of the gas discharged from the central discharge port 45c of the fluid nozzle 45 when forming the exposure hole HL in the central portion of the liquid film covering the entire upper surface of the substrate W. The hole expansion flow rate is the flow rate of the gas discharged from the central discharge port 45c of the fluid nozzle 45 when expanding the outer edge HLe of the exposure hole HL corresponding to the inner circumference of the ring-shaped liquid film to the outer circumference of the upper surface of the substrate W. The hole expansion flow rate is equal to or greater than the minimum value of the flow rate of the gas that can expand the outer edge HLe of the exposure hole HL to the outer circumference of the upper surface of the substrate W. If the hole expansion flow rate is greater than the hole formation flow rate, the hole formation flow rate may be equal to or greater than the same minimum value, or may be less than the same minimum value.

[0102] In the example shown in FIG. 6, the central gas flow rate gradually increases from the hole formation flow rate to the hole expansion flow rate during the period from time T2 to time T4. In this example, the central gas flow rate gradually increases by a first increase amount during the period from time T2 to time T3, and gradually increases by a second increase amount during the period from time T3 to time T4. The second increase amount is larger than the first increase amount. Therefore, the increase amount of the flow rate of the inert gas per unit time gradually increases with the passage of time. The second increase amount may be less than or equal to the first increase amount. The central gas flow rate reaches the hole expansion flow rate at time T4 and is maintained at the hole expansion flow rate until time T5.

[0103] The central gas flow rate (the flow rate of the inert gas discharged from the central discharge port 45c of the fluid nozzle 45) increases to the hole expansion flow rate in a state where the fluid nozzle 45 is disposed at the central upper position. The inner diameter of the ring-shaped IPA liquid film surrounding the exposed hole HL increases with the passage of time during which the central discharge port 45c discharges the inert gas. The increase in the central gas flow rate accelerates the increase in the inner diameter. The outer edge HLe of the exposed hole HL may reach the outer periphery of the substrate W before the central gas flow rate reaches the hole expansion flow rate, or may reach the outer periphery of the substrate W after the central gas flow rate reaches the hole expansion flow rate.

[0104] After all of the IPA liquid film has disappeared from the upper surface of the substrate W, at time T5, the hot plate 61 is lowered from the upper position to the separated position. When the lowering of the hot plate 61 is started, the plurality of chuck pins 11 are disposed at the open position. Therefore, the substrate W is supported by the plurality of open chuck pins 11 and separated from the hot plate 61 before the hot plate 61 reaches the separated position. Thereafter, at time T6, the plurality of chuck pins 11 are disposed at the closed position, and at time T7, the rotation of the substrate W is started.

[0105] When a plurality of chuck pins 11 move from the open position to the closed position (time T6), the hot plate 61 is arranged at the separated position while being maintained at the heating temperature. Therefore, compared with the case where the plurality of chuck pins 11 are moved from the open position to the closed position with the hot plate 61 arranged at the lower position, a decrease in the temperature of the substrate W can be reduced. The hot plate 61 descends from the separated position to the lower position simultaneously with the start of the rotation of the substrate W at time T7. The hot plate 61 may start to descend from the separated position before or after the rotation of the substrate W is started.

[0106] After the rotation of the substrate W is started at time T7, the rotation speed of the substrate W increases to the drying speed and is maintained at the drying speed. FIG. 6 shows an example in which the rotation speed of the substrate W increases stepwise to the drying speed via an intermediate speed. In this example, the intermediate speed is 100 rpm and the drying speed is 800 rpm. The time during which the rotation speed of the substrate W is maintained at the intermediate speed may be equal to or different from the time during which the rotation speed of the substrate W is maintained at the drying speed. After the rotation speed of the substrate W is maintained at the drying speed, the rotation of the substrate W is stopped at time T8.

[0107] On the other hand, after the central gas flow rate (the flow rate of the inert gas discharged from the central discharge port 45c of the fluid nozzle 45) is maintained at the hole expansion flow rate, at time T5, the central gas flow rate is decreased from the hole expansion flow rate to the drying flow rate and maintained at the drying flow rate. FIG. 6 shows an example in which the central gas flow rate is maintained at the drying flow rate during the period from time T5 to time T8 and decreased to zero at time T8. The drying flow rate is larger than the hole formation flow rate and smaller than the hole expansion flow rate. In the example shown in FIG. 6, the hole formation flow rate is 1.9 L / min, the hole expansion flow rate is 70 L / min, and the drying flow rate is 30 L / min. When the central gas flow rate is the drying flow rate, the substrate W may be maintained at a temperature higher than room temperature or may be at room temperature.

[0108] The fluid nozzle 45 is disposed at the central upper position during the period from time T2 to time T8. Therefore, when the central discharge port 45c of the fluid nozzle 45 discharges the inert gas at the drying flow rate, the fluid nozzle 45 is disposed at the central upper position. The fluid nozzle 45 may discharge the inert gas at the drying flow rate from the central discharge port 45c while being located at the central lower position. When the central discharge port 45c stops discharging the inert gas at time T8, the fluid nozzle 45 simultaneously starts to move from the central upper position toward the standby position. The fluid nozzle 45 may start to move from the central upper position toward the standby position after the central discharge port 45c stops discharging the inert gas.

[0109] When the central discharge port 45c of the fluid nozzle 45 discharges the inert gas at the drying flow rate, all of the liquid film of IPA has disappeared from the upper surface of the substrate W (see FIG. 5F). The inert gas discharged from the central discharge port 45c forms a columnar or linear air flow extending from the central discharge port 45c to the central portion of the upper surface of the substrate W. The inert gas collides perpendicularly or almost perpendicularly with the collision position within the central portion of the upper surface of the substrate W and then flows outward in all directions along the upper surface of the substrate W. Therefore, an outward air flow is formed in the region within the upper surface of the substrate W other than the central portion.

[0110] On the other hand, in the central portion of the upper surface of the substrate W, a small amount of vapor of IPA may be pressed against the substrate W by the inert gas discharged from the central discharge port 45c and remain. When this vapor returns to the liquid state, there is a possibility that stains such as watermarks are formed in the central portion of the upper surface of the substrate W, or the pattern PA collapses in the central portion of the upper surface of the substrate W. As described above, the drying flow rate is smaller than the hole expansion flow rate. Therefore, compared with the case where the central discharge port 45c continuously discharges the inert gas at the hole expansion flow rate, the vapor of IPA remaining in the central portion of the upper surface of the substrate W can be reduced. Thereby, while protecting the entire area of the upper surface of the substrate W with the inert gas discharged from the central discharge port 45c, it is possible to prevent or reduce the deterioration of the quality of the substrate W.

[0111] FIG. 6 shows an example in which the first annular discharge port 45a and the second annular discharge port 45b of the fluid nozzle 45 continuously discharge an inert gas during the period from time T4 to time T8. In this example, each of the first annular discharge port 45a and the second annular discharge port 45b discharges an inert gas at 100 L / min. The velocity of the inert gas discharged from the first annular discharge port 45a is greater than the velocity of the inert gas discharged at the drying flow rate from the central discharge port 45c. The same applies to the velocity of the inert gas discharged from the second annular discharge port 45b. The first annular discharge port 45a and the second annular discharge port 45b may start discharging the inert gas before the exposure holes HL are formed in the liquid film of IPA, or may start discharging the inert gas after all of the liquid film of IPA has disappeared from the upper surface of the substrate W.

[0112] When the inner diameter of the ring-shaped liquid film of IPA increases, the area of the exposed portion exposed from the liquid film of IPA on the upper surface of the substrate W increases. The exposed portion within the upper surface of the substrate W is protected not only by the inert gas discharged from the central discharge port 45c of the fluid nozzle 45 but also by the inert gas discharged from the first annular discharge port 45a and the second annular discharge port 45b of the fluid nozzle 45. Thereby, the evaporation of IPA from the substrate W can be promoted, and the particles adhering to the upper surface of the substrate W can be reduced.

[0113] Next, the effects of the present embodiment will be described.

[0114] In the present embodiment, a gas is discharged at a hole-forming flow rate from the central discharge port 45c of the fluid nozzle 45 located above the horizontally held substrate W toward the central portion of the upper surface of the substrate W. Thereby, the exposure holes HL are formed in the central portion of the liquid film, and the central portion of the upper surface of the substrate W is exposed from the liquid film. Thereafter, a gas is discharged at a hole-expanding flow rate greater than the hole-forming flow rate from the central discharge port 45c toward the central portion of the upper surface of the substrate W. Thereby, the velocity of the gas discharged from the central discharge port 45c increases as compared with when the gas is discharged at the hole-forming flow rate from the central discharge port 45c.

[0115] The gas discharged from the central discharge port 45c collides with the upper surface of the substrate W in the exposure hole HL and then flows outward in all directions along the upper surface of the substrate W. IPA, which is an example of the processing liquid, is pushed outward by this gas. Furthermore, since the flow rate of the gas discharged from the central discharge port 45c is increased compared to when the exposure hole HL was formed, the outward movement of IPA is promoted. As a result, the outer edge HLe of the exposure hole HL corresponding to the inner circumference of the ring-shaped liquid film spreads to the outer circumference of the upper surface of the substrate W, and all of the liquid film is discharged from the upper surface of the substrate W.

[0116] When forming the exposure hole HL, the fluid nozzle 45 is disposed at the central lower position which is above the substrate W and discharges gas at the hole formation flow rate. The gas discharged from the central discharge port 45c forms a columnar or linear air flow extending from the central discharge port 45c to the upper surface of the substrate W. The diameter of the air flow increases as it moves away from the central discharge port 45c. When forming the exposure hole HL, if an air flow with a large diameter collides with the liquid film, IPA is likely to remain in the exposure hole HL. Therefore, compared with the case of forming the exposure hole HL with the gas discharged from the central discharge port 45c of the fluid nozzle 45 located at the central upper position, the air flow colliding with the liquid film on the substrate W can be made thinner, and the possibility of IPA remaining in the exposure hole HL when the exposure hole HL is formed can be reduced.

[0117] When expanding the exposure hole HL, the fluid nozzle 45 is disposed at the central upper position which is above the central lower position and discharges gas at a hole expansion flow rate larger than the hole formation flow rate. If gas is discharged at a large flow rate from the central discharge port 45c while keeping the central discharge port 45c close to the substrate W, air flows other than the air flow parallel or substantially parallel to the upper surface of the substrate W may increase or become stronger. Such air flow turbulence may generate droplets scattered toward the exposure hole HL or may prevent the outward movement of IPA. Therefore, compared with the case of discharging gas at the hole expansion flow rate from the central discharge port 45c of the fluid nozzle 45 located at the central lower position, the air flow turbulence can be reduced or weakened.

[0118] In the present embodiment, not only when discharging gas from the central discharge port 45c of the fluid nozzle 45 at the hole expansion flow rate, but also when increasing the flow rate of the gas discharged from the central discharge port 45c to the hole expansion flow rate, the fluid nozzle 45 is positioned at the central upper position. Therefore, when increasing the flow rate of the gas discharged from the central discharge port 45c, the turbulence of the air flow generated above the substrate W can be reduced or weakened, and the outer edge HLe of the exposure hole HL can be smoothly brought closer to the outer periphery of the upper surface of the substrate W.

[0119] In the present embodiment, when increasing the flow rate of the gas discharged from the central discharge port 45c of the fluid nozzle 45 positioned at the central upper position to the hole expansion flow rate, the increase amount of the gas flow rate per unit time is continuously or stepwise increased with the passage of time. The rate at which the inner diameter of the ring-shaped IPA liquid film increases is approximately proportional to the flow rate of the gas discharged from the central discharge port 45c. Therefore, the same rate increases with the passage of time. In other words, the inner circumference of the ring-shaped IPA liquid film spreads slowly first and then spreads rapidly. As a result, it is possible to shorten the time for discharging the IPA liquid film while preventing the IPA liquid film from splitting on the upper surface of the substrate W or droplets from being generated from the IPA liquid film and scattering toward the exposure hole HL.

[0120] In the present embodiment, gas is discharged radially from the first annular discharge port 45a and the second annular discharge port 45b surrounding the rotation axis A1 of the substrate W, which is an example of a vertical line passing through the central portion of the upper surface of the substrate W. Thereby, the upper surface of the substrate W can be covered with the gas discharged from the first annular discharge port 45a and the second annular discharge port 45b. Further, the first annular discharge port 45a and the second annular discharge port 45b start discharging gas after the exposure hole HL is formed, not before. Therefore, the gas discharged from the first annular discharge port 45a and the second annular discharge port 45b does not prevent the formation of the exposure hole HL. After the exposure hole HL is formed, the gas discharged from the first annular discharge port 45a and the second annular discharge port 45b guides the gas discharged from the central discharge port 45c outward along the upper surface of the substrate W. Thereby, the outer edge HLe of the exposure hole HL can be surely brought closer to the outer periphery of the upper surface of the substrate W.

[0121] In this embodiment, while discharging gas at a drying flow rate from the central discharge port 45c of the fluid nozzle 45 toward the central portion of the upper surface of the substrate W, the substrate W is rotated. Even if droplets of a size that cannot be visually observed remain on the upper surface of the substrate W, such droplets evaporate while the substrate W is rotating. Thereby, the upper surface of the substrate W can be dried while protecting the upper surface of the substrate W with the gas discharged from the central discharge port 45c. The drying flow rate is larger than the hole forming flow rate and smaller than the hole expanding flow rate. In the central portion of the upper surface of the substrate W, a small amount of IPA vapor may be pressed against and retained on the substrate W by the gas discharged from the central discharge port 45c. Therefore, compared with the case where the central discharge port 45c continuously discharges gas at the hole expanding flow rate, the IPA vapor retained in the central portion of the upper surface of the substrate W can be reduced, and the deterioration of the quality of the substrate W caused by the vapor can be prevented or reduced.

[0122] In this embodiment, not only is the substrate W rotated while discharging gas at a drying flow rate from the central discharge port 45c of the fluid nozzle 45 toward the central portion of the upper surface of the substrate W, but also gas is discharged radially from the first annular discharge port 45a and the second annular discharge port 45b. Therefore, not only the gas discharged from the central discharge port 45c but also the gas discharged from the first annular discharge port 45a and the second annular discharge port 45b can protect the upper surface of the substrate W. The flow rate of the gas discharged from the central discharge port 45c when drying the substrate W is smaller than the flow rate of the gas discharged from the first annular discharge port 45a and the second annular discharge port 45b when drying the substrate W. Thereby, the IPA vapor retained in the central portion of the upper surface of the substrate W can be reduced. On the other hand, in the region within the upper surface of the substrate W other than the central portion, the gas discharged from the first annular discharge port 45a and the second annular discharge port 45b accelerates the gas discharged from the central discharge port 45c outward along the upper surface of the substrate W. Thereby, the drying of the substrate W can be promoted.

[0123] In this embodiment, by heating the substrate W, IPA is evaporated at the interface between the liquid film of IPA and the upper surface of the substrate W. As a result, a vapor layer VL containing IPA is formed between the liquid film of IPA and the upper surface of the substrate W. All or part of the liquid film of IPA is supported on the upper surface of the substrate W via the vapor layer VL of IPA and floats from the upper surface of the substrate W. In this state, an exposure hole HL is formed, and the outer edge HLe of the exposure hole HL is expanded to the outer periphery of the upper surface of the substrate W. Since the substrate W is being heated, if droplets remain in the exposure hole HL when the exposure hole HL is formed, or if droplets scattered from the liquid film enter the exposure hole HL when the exposure hole HL is being expanded, the droplets will immediately evaporate. By eliminating or reducing such droplets, it is possible to reduce the possibility of stains such as watermarks forming on the upper surface of the substrate W or the pattern PA collapsing on the upper surface of the substrate W.

[0124] Next, another embodiment will be described.

[0125] If the fluid nozzle 45 can be vertically translated above the substrate W held by the spin chuck 10, the fluid nozzle 45 does not necessarily have to be horizontally movable.

[0126] At least one of the solvent nozzle 45D and the first gas nozzle 45C of the fluid nozzle 45 does not necessarily have to be held by the second gas nozzle 45A of the fluid nozzle 45. In this case, if the solvent nozzle 45D is a scan nozzle, a nozzle actuator dedicated to the solvent nozzle 45D may be provided. The same applies to the first gas nozzle 45C.

[0127] If it is not immediately after the exposure hole HL is formed, that is, after the exposure hole HL has become a certain size, while positioning the fluid nozzle 45 at the central lower position, the flow rate of the gas discharged from the central discharge port 45c of the fluid nozzle 45 may be increased to the hole expansion flow rate. Thereafter, while discharging gas at the hole expansion flow rate from the central discharge port 45c, the fluid nozzle 45 may be raised to the central upper position.

[0128] Before forming the exposure hole HL, gas discharge may be started from the first annular discharge port 45a of the fluid nozzle 45. The same applies to the second annular discharge port 45b of the fluid nozzle 45. The flow rate of the gas discharged from at least one of the first annular discharge port 45a and the second annular discharge port 45b may be equal to or less than the maximum value of the flow rate of the gas discharged from the central discharge port 45c. After forming the exposure hole HL and before drying the substrate W by spin drying, gas discharge from the first annular discharge port 45a and the second annular discharge port 45b may be stopped.

[0129] Rather than in a state where the liquid film of IPA has floated from the upper surface of the substrate W, the liquid film of IPA may be discharged from the upper surface of the substrate W by widening the exposure hole HL in a state where the liquid film of IPA is in contact with the upper surface of the substrate W. In this case, the hot plate 61 may be omitted.

[0130] The substrate processing apparatus 1 is not limited to an apparatus for processing a disc-shaped substrate W, and may be an apparatus for processing a polygonal substrate W.

[0131] Two or more of all the above-described configurations may be combined. Two or more of all the above-described steps may be combined.

[0132] Although the embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical content of the present invention, and the present invention should not be construed as being limited to these specific examples. The spirit and scope of the present invention are limited only by the appended claims.

Explanation of Reference Numerals

[0133] 1: Substrate processing apparatus, 10: Spin chuck, 11: Chuck pin, 12: Spin base, 45: Fluid nozzle, 45a: First annular discharge port, 45b: Second annular discharge port, 45c: Central discharge port, 45d: Solvent discharge port, 45D: Solvent nozzle, 48f: Flow rate adjustment valve, 52a: Nozzle actuator, 61: Hot plate, A1: Axis of rotation, HL: Exposure hole, HLe: Outer edge, L1: Center line, VL: Vapor layer, W: Substrate

Claims

1. A liquid film forming step of covering the entire upper surface of the substrate with a liquid film which is a film of the processing liquid by discharging the processing liquid toward the upper surface of the substrate held horizontally; A hole forming step of forming an exposed hole in which the central portion of the upper surface of the substrate is exposed at the central portion of the liquid film by discharging a gas at a hole forming flow rate from a central discharge port of a fluid nozzle located at a central lower position which is a position above the substrate, toward the central portion of the upper surface of the substrate; A substrate processing method, comprising: a hole expanding step of expanding the outer edge of the exposed hole to the outer periphery of the upper surface of the substrate by discharging a gas at a hole expanding flow rate larger than the hole forming flow rate from the central discharge port of the fluid nozzle located at a central upper position which is a position higher than the central lower position, toward the central portion of the upper surface of the substrate.

2. The substrate processing method according to claim 1, wherein the hole expanding step includes a step of increasing the flow rate of the gas discharged from the central discharge port to the hole expanding flow rate when the fluid nozzle is located at the central upper position.

3. The substrate processing method according to claim 2, wherein the hole expanding step includes a step of increasing the flow rate of the gas discharged from the central discharge port to the hole expanding flow rate while increasing an increase amount of the flow rate of the gas per unit time as time elapses when the fluid nozzle is located at the central upper position.

4. The substrate processing method according to any one of claims 1 to 3, further comprising a radial air flow forming step of covering the upper surface of the substrate with a gas discharged radially from an annular discharge port surrounding a vertical line passing through the central portion of the upper surface of the substrate after the exposed hole is formed.

5. The substrate processing method according to any one of claims 1 to 3, further comprising a spin drying step of rotating the substrate around a vertical rotation axis passing through the central portion of the upper surface of the substrate while discharging a gas toward the central portion of the upper surface of the substrate at a drying flow rate larger than the hole forming flow rate and smaller than the hole expanding flow rate from the central discharge port after the outer edge of the exposed hole has spread to the outer periphery of the upper surface of the substrate.

6. The substrate processing method further includes a radial air flow forming step of covering the upper surface of the substrate with a gas discharged radially from an annular discharge port surrounding a vertical line passing through the central portion of the upper surface of the substrate when the spin drying step is being performed. The substrate processing method according to claim 5, wherein the drying flow rate is smaller than the flow rate of the gas discharged from the annular discharge port when the radial airflow forming step is being performed.

7. The substrate processing method according to any one of claims 1 to 3, further comprising a liquid film floating step of forming a vapor layer of the processing liquid that floats the liquid film from the upper surface of the substrate between the liquid film and the upper surface of the substrate by heating the substrate before the exposure hole is formed.

8. A substrate holder that holds the substrate horizontally, A processing liquid nozzle that covers the entire upper surface of the substrate with a liquid film that is a film of the processing liquid by discharging the processing liquid toward the upper surface of the substrate held by the substrate holder, A fluid nozzle that forms an exposure hole in which the central portion of the upper surface of the substrate is exposed at the central portion of the liquid film by discharging gas from a central discharge port toward the central portion of the upper surface of the substrate held by the substrate holder when located at a central lower position that is above the substrate, A nozzle actuator that raises the fluid nozzle from the central lower position to a central upper position, A flow rate adjustment valve that discharges gas at a hole expansion flow rate larger than the hole formation flow rate from the central discharge port of the fluid nozzle toward the central portion of the upper surface of the substrate held by the substrate holder when the fluid nozzle is located at the central upper position, by changing the flow rate of the gas discharged from the central discharge port of the fluid nozzle, and expands the outer edge of the exposure hole to the outer periphery of the upper surface of the substrate. A substrate processing apparatus comprising:

Images