Substrate processing device and substrate processing method

Abstract

A substrate processing device comprises a processing liquid nozzle 30 that ejects a processing liquid downward toward an upper surface of a substrate. An outer surface 30s of the processing liquid nozzle 30 includes a water-repellent surface 72.

Description

Substrate processing apparatus and substrate processing method Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2023-159046 filed on September 22, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a substrate processing apparatus and a substrate processing method for processing substrates, including, for example, semiconductor wafers, substrates for FPDs (Flat Panel Displays) 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, and substrates for solar cells.

[0003] Patent Document 1 discloses that a processing liquid is ejected from an upper processing liquid nozzle located at a processing position toward the upper surface of a substrate rotating in a horizontal position, and that the upper processing liquid nozzle located at a standby position is washed with a cleaning liquid and dried.

[0004] JP 2013-26379 A

[0005] In the substrate processing apparatus and substrate processing method described in Patent Document 1, mist and droplets of the processing liquid ejected from the upper processing liquid nozzle may adhere to the upper processing liquid nozzle and fall from the upper processing liquid nozzle onto the substrate. If the upper processing liquid nozzle is not sufficiently dried, liquid such as a cleaning liquid may fall from the upper processing liquid nozzle onto the substrate when the upper processing liquid nozzle is moved toward the processing position. However, the liquid falling from the upper processing liquid nozzle onto the substrate may degrade the quality of the substrate.

[0006] At least one embodiment of the present invention provides a substrate processing apparatus and a substrate processing method that can reduce liquid dropping onto a substrate from a processing liquid nozzle at unexpected times.

[0007] One embodiment of the present invention provides a substrate processing apparatus comprising a substrate holder that holds a substrate horizontally and a processing liquid nozzle that ejects a processing liquid downward toward the upper surface of the substrate held by the substrate holder, wherein the outer surface of the processing liquid nozzle includes a water-repellent surface.

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

[0009] The water-repellent surface includes an uneven surface including recesses at least partially filled with air and protrusions in contact with water that is in contact with the air in the recesses.

[0010] The uneven surface is made of a fluororesin.

[0011] The outer surface of the treatment liquid nozzle includes the water-repellent surface and a mirror surface.

[0012] The processing liquid nozzle includes an arm portion extending horizontally and a nozzle portion extending downward from the arm portion and discharging the processing liquid downward, and the mirror surface is provided on the nozzle portion.

[0013] The water-repellent surface is provided on the arm portion.

[0014] The contact angle of water on the mirror surface is greater than 90 degrees.

[0015] The substrate processing apparatus further includes a spin motor that rotates the substrate held by the substrate holder around a vertical axis of rotation that passes through the center of the substrate; a horizontal actuator that generates power to move the processing liquid nozzle horizontally between a processing position where the processing liquid nozzle overlaps the substrate held by the substrate holder in a planar view and a standby position where the processing liquid nozzle does not overlap the substrate held by the substrate holder in a planar view; and a control device that, after the processing liquid nozzle located at the processing position supplies the processing liquid to the top surface of the substrate held by the substrate holder, moves the processing liquid nozzle from the processing position to the standby position by the horizontal actuator while drying the substrate by rotating the substrate with the spin motor.

[0016] The substrate processing apparatus further includes a horizontal actuator that generates power to move the processing liquid nozzle horizontally between a processing position where the processing liquid nozzle overlaps the substrate held by the substrate holder in a planar view and a standby position where the processing liquid nozzle does not overlap the substrate held by the substrate holder in a planar view, a cleaning nozzle that sprays a cleaning liquid toward the outer surface of the processing liquid nozzle located at the standby position, and a drying nozzle that sprays a drying gas toward the outer surface of the processing liquid nozzle located at the standby position.

[0017] Another embodiment of the present invention provides a substrate processing method, the method including the steps of: discharging a processing liquid downward from a processing liquid nozzle toward an upper surface of a substrate held horizontally by a substrate holder; and contacting mist and droplets generated while the processing liquid nozzle is discharging the processing liquid with a water-repellent surface provided on an outer surface of the processing liquid nozzle. At least one of the above-described features of the substrate processing apparatus may be added to the substrate processing method.

[0018] The above and other objects, features and advantages of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings.

[0019] 1 is a schematic plan view showing a layout of a substrate processing apparatus according to an embodiment of the present invention; FIG. 2 is a schematic side view of the substrate processing apparatus; FIG. 3 is a schematic view showing the interior of a processing unit provided in the substrate processing apparatus when viewed horizontally; FIG. 4 is a schematic plan view showing the interior of the processing unit; FIG. 5 is a schematic view showing a processing liquid nozzle when viewed horizontally, perpendicular to the center line of an arm; FIG. 6 is a block diagram showing the electrical configuration of the substrate processing apparatus; FIG. 7 is a process diagram for explaining an example of substrate processing performed by the substrate processing apparatus; FIG. 8 is a schematic plan view showing a processing liquid nozzle, a cleaning nozzle, a first drying nozzle, and a second drying nozzle; FIG. 9 is a schematic view showing the processing liquid nozzle, the cleaning nozzle, the first drying nozzle, and the second drying nozzle when viewed horizontally; FIG. 10 is a schematic view showing an example of a water-repellent surface and a mirror surface provided on the outer surface of the processing liquid nozzle; FIG. 11 is a schematic cross-sectional view showing an example of a droplet coming into contact with a smooth surface; FIG. 12 is a schematic cross-sectional view showing an example of a droplet coming into contact with a rough surface in a Wenzel state; FIG. 13 is a schematic cross-sectional view showing an example of a droplet coming into contact with a rough surface in a Cassie-Baxter state; FIG. 14 is a schematic view for explaining mist and droplets generated when the processing liquid nozzle is discharging the processing liquid; and FIG. 15 is a schematic view showing a state in which the processing liquid nozzle is being moved from a processing position to a standby position while drying the substrate. FIG. 10 is a schematic diagram showing a processing liquid nozzle according to another embodiment of the present invention, viewed horizontally.

[0020] 1A is a schematic plan view showing the layout of a substrate processing apparatus 1 according to an embodiment of the present invention, and FIG.

[0021] The substrate processing apparatus 1 is a single-wafer processing 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 carriers CA that accommodate substrates W, a plurality of processing units 2 that process the substrates W transferred from the carriers CA on the load port LP with processing fluids such as processing liquids and processing gases, a transport system TS that transports the substrates W between the carriers CA on the load port LP and the plurality of processing units 2, and a control device 3 that controls the substrate processing apparatus 1.

[0022] The multiple processing units 2 form multiple towers TW. Fig. 1A shows an example in which four towers TW are formed. As shown in Fig. 1B, the multiple processing units 2 included in one tower TW are stacked one above the other. As shown in Fig. 1A, the multiple towers TW form two rows extending in the depth direction of the substrate processing apparatus 1 in a plan view. In a plan view, the two rows face each other across a transport path TP.

[0023] The transport system TS includes an indexer robot IR that transports substrates W between a carrier CA on a load port LP and the plurality of processing units 2, and a center robot CR that transports substrates W between the indexer robot IR and the plurality of processing units 2. The indexer robot IR is disposed between the load port LP and the center robot CR in a plan view. The center robot CR is disposed on the transport path TP.

[0024] The indexer robot IR includes one or more hands Hi that horizontally support a substrate W. The hands Hi can move parallel to both the horizontal and vertical directions. The hands Hi can rotate about a vertical line. The hands Hi can load and unload a substrate W into and from a carrier CA on any of the load ports LP, and can transfer a substrate W to and from the center robot CR.

[0025] The center robot CR includes one or more hands Hc that horizontally support a substrate W. The hands Hc can move parallel to both the horizontal and vertical directions. The hands Hc can rotate about a vertical line. The hands Hc can transfer substrates W to and from the indexer robot IR, and can transport substrates W into and out of any of the processing units 2.

[0026] Next, the processing unit 2 will be described.

[0027] Fig. 2 is a horizontal schematic view of the interior of the processing unit 2 provided in the substrate processing apparatus 1. Fig. 3 is a schematic plan view showing the interior of the processing unit 2. Fig. 4 is a schematic view of the processing liquid nozzle 30 viewed in a horizontal direction perpendicular to the center line of the arm portion 28.

[0028] As shown in Figure 2, the processing unit 2 includes a box-shaped chamber 4 having an internal space, a spin chuck 10 that holds a single substrate W horizontally within the chamber 4 and rotates it around a vertical rotation axis A1 passing through the center of the substrate W, and a cylindrical processing cup 21 that surrounds the spin chuck 10 around the rotation axis A1.

[0029] The chamber 4 includes a box-shaped partition 5 provided with an inlet / outlet port 5b through which the substrate W passes, and a door 7 for opening and closing the inlet / outlet port 5b. An FFU 6 (fan filter unit) is disposed above an air outlet 5a disposed at the top of the partition 5. The FFU 6 constantly supplies clean air (air filtered by a filter) into the chamber 4 through the air outlet 5a. The gas within the chamber 4 is exhausted from the chamber 4 through an exhaust duct 8 connected to the bottom of the processing cup 21. This constantly creates a downflow of clean air within the chamber 4. The flow rate of the exhaust gas discharged into the exhaust duct 8 is changed depending on the opening degree of an exhaust valve 9 disposed in the exhaust duct 8.

[0030] The spin chuck 10 includes a disk-shaped spin base 12 held horizontally, a plurality of chuck pins 11 that hold the substrate W horizontally above the spin base 12, a spin shaft 13 that extends downward from the center 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.

[0031] The spin chuck 10 is not limited to a clamping type chuck in which multiple chuck pins 11 contact the edge surface of the substrate W, but may also be a vacuum type chuck that holds the substrate W horizontally by adsorbing the back surface (lower surface) of the substrate W, which is not a device formation surface, to the upper surface 12u of the spin base 12. When the spin chuck 10 is a clamping type chuck, the multiple chuck pins 11 correspond to the substrate holder. When the spin chuck 10 is a vacuum type chuck, the spin base 12 corresponds to the substrate holder.

[0032] The processing cup 21 includes a plurality of guards 24 that receive the processing liquid discharged outward from the substrate W, a plurality of cups 23 that receive the processing liquid guided downward by the plurality of guards 24, and a cylindrical outer wall member 22 that surrounds the plurality of guards 24 and the plurality of cups 23. Figure 2 shows an example in which four guards 24 and three cups 23 are provided, and the outermost cup 23 is integrated with the third guard 24 from the top.

[0033] The guard 24 includes a cylindrical portion 25 surrounding the spin chuck 10 and an annular ceiling portion 26 extending obliquely upward from the upper end of the cylindrical portion 25 toward the rotation axis A1. The multiple ceiling portions 26 are stacked one on top of the other, and the multiple cylindrical portions 25 are arranged concentrically. The upper end of the annular ceiling portion 26 corresponds to an upper end 24u of the guard 24 surrounding the substrate W and the spin base 12 in a plan view. The multiple cups 23 are respectively arranged below the multiple cylindrical portions 25. The cups 23 form annular grooves that receive the processing liquid guided downward by the guard 24.

[0034] The processing unit 2 includes a guard lifting unit 27 that individually lifts and lowers the multiple guards 24. The guard lifting unit 27 positions the guards 24 at any position within a range from the upper position to the lower position. Fig. 2 shows a state in which two guards 24 are positioned at the upper position and the remaining two guards 24 are positioned at the lower position. The upper position is a position in which the upper ends 24u of the guards 24 are positioned above the holding position in which the substrate W held by the spin chuck 10 is positioned. The lower position is a position in which the upper ends 24u of the guards 24 are positioned below the holding position.

[0035] The processing unit 2 includes three processing liquid nozzles 30 that discharge processing liquid downward toward the upper surface of the substrate W held on the spin chuck 10. The three processing liquid nozzles 30 are composed of a chemical liquid nozzle 31 that discharges a chemical liquid downward toward the upper surface of the substrate W, a rinse liquid nozzle 32 that discharges a rinse liquid downward toward the upper surface of the substrate W, and a solvent nozzle 33 that discharges an organic solvent downward toward the upper surface of the substrate W. FIG. 2 shows an example in which the rinse liquid nozzle 32 discharges deionized water (DIW) and the solvent nozzle 33 discharges isopropyl alcohol (IPA). DIW stands for pure water (deionized water). Unless otherwise specified, organic solvent refers to a liquid organic solvent. The same applies to IPA. Hereinafter, when there is no need to distinguish between the chemical liquid nozzle 31, rinse liquid nozzle 32, and solvent nozzle 33, they may be simply referred to as processing liquid nozzles 30.

[0036] The chemical nozzle 31 is connected to a chemical pipe 31p that guides the chemical. When a chemical valve 31v attached to the chemical pipe 31p is opened, the chemical is continuously discharged downward from the discharge port of the chemical nozzle 31. The chemical may be a liquid containing at least one of sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia water, hydrogen peroxide, an organic acid (e.g., citric acid, oxalic acid, etc.), an organic alkali (e.g., TMAH: tetramethylammonium hydroxide, etc.), a surfactant, and a corrosion inhibitor, or may be another liquid.

[0037] Although not shown, the chemical liquid valve 31v includes a valve body with an annular valve seat through which the chemical liquid passes, a valve element that is movable relative to the valve seat, and an actuator that moves the valve element between a closed position in which the valve element contacts the valve seat and an open position in which the valve element is separated from the valve seat. The same applies to the other valves. The actuator may be a pneumatic actuator, an electric actuator, or another type of actuator. The control device 3 controls the actuator to open and close the chemical liquid valve 31v, etc.

[0038] The rinse liquid nozzle 32 is connected to a rinse liquid pipe 32p that guides the rinse liquid. When a rinse liquid valve 32v attached to the rinse liquid pipe 32p is opened, the rinse liquid is continuously discharged downward from the discharge port of the rinse liquid nozzle 32. The rinse liquid may be any one of pure water, carbonated water, electrolytic ionized water, hydrogen water, ozone water, and hydrochloric acid water with a diluted concentration (for example, about 10 to 100 ppm), or may be any other liquid.

[0039] The solvent nozzle 33 is connected to a solvent pipe 33p that guides the organic solvent. When a solvent valve 33v attached to the solvent pipe 33p is opened, the organic solvent is continuously discharged downward from the discharge port of the solvent nozzle 33. The organic solvent may be an alcohol other than IPA, or an organic solvent other than alcohol, such as HFE (hydrofluoroether). IPA has a higher vapor pressure than water and a lower surface tension than water.

[0040] The chemical nozzle 31 may be a scan nozzle that moves the collision position of the chemical solution on 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 solution on the substrate W. The same applies to the other nozzles. Figure 2 shows an example in which the chemical nozzle 31, the rinse liquid nozzle 32, and the solvent nozzle 33 are scan nozzles.

[0041] The processing unit 2 includes a nozzle moving unit 30m that moves at least one nozzle horizontally. Fig. 3 shows an example in which three processing liquid nozzles 30 are connected to the nozzle moving unit 30m. In this example, the nozzle moving unit 30m moves the three processing liquid nozzles 30 in the horizontal and vertical directions while maintaining constant relative positions of the three processing liquid nozzles 30. The processing unit 2 may include three nozzle moving units 30m that respectively correspond to the three processing liquid nozzles 30.

[0042] The three processing liquid nozzles 30 are connected to a nozzle movement unit 30m via brackets 30b. The processing liquid nozzle 30 includes a nozzle portion 29 that discharges the processing liquid downward and an arm portion 28 that supports the nozzle portion 29. FIG. 4 shows an example in which the processing liquid nozzle 30 is L-shaped rotated by 90 degrees. In this example, the nozzle portion 29 is cylindrical and extends vertically, and the arm portion 28 is cylindrical and extends horizontally. The nozzle portion 29 extends downward from a tip 28d of the arm portion 28. The tip 28d of the arm portion 28 is the end-most portion in the direction along the center line of the arm portion 28 when viewed from directly above (see FIG. 3).

[0043] The arm portion 28 is connected to the nozzle moving unit 30m via a bracket 30b. The power of the nozzle moving unit 30m is transmitted to the nozzle portion 29 via the arm portion 28. Figures 3 and 4 show an example in which three processing liquid nozzles 30 are held by the nozzle moving unit 30m so that the three nozzle portions 29 are arranged parallel to one another and the three arm portions 28 are arranged parallel to one another.

[0044] The length of the nozzle portion 29, i.e., the shortest vertical distance from the upper end of the nozzle portion 29 to the lower end of the nozzle portion 29, is shorter than the length of the arm portion 28, i.e., the shortest horizontal distance from the tip 28d of the arm portion 28 to the base of the arm portion 28. The thickness of the nozzle portion 29, i.e., the maximum value of the length of a straight line connecting two points on the outline of the cross section of the nozzle portion 29 perpendicular to the center line of the nozzle portion 29, is shorter than the length of the nozzle portion 29. The thickness of the arm portion 28, i.e., the maximum value of the length of a straight line connecting two points on the outline of the cross section of the arm portion 28 perpendicular to the center line of the arm portion 28, is shorter than the length of the arm portion 28. The thickness of the nozzle portion 29 may be equal to or different from the thickness of the arm portion 28.

[0045] The thickness of the nozzle portion 29 may be constant from the upper end to the lower end of the nozzle portion 29, or may change continuously or stepwise as the nozzle portion 29 approaches the lower end. In the latter case, the nozzle portion 29 may include a portion where the thickness of the nozzle portion 29 changes continuously as the nozzle portion 29 approaches the lower end, and a portion where the thickness of the nozzle portion 29 changes stepwise as the nozzle portion 29 approaches the lower end. The nozzle portion 29 may have a columnar shape other than a circular column, such as a rectangular prism. The center line of the nozzle portion 29 may be vertical or may be inclined relative to a vertical straight line. A portion of the center line of the nozzle portion 29 may be vertical, and the remaining portion of the center line of the nozzle portion 29 may be inclined relative to a vertical straight line.

[0046] The arm portion 28 is continuous from the bracket 30b to the nozzle portion 29. The arm portion 28 is integral with the nozzle portion 29. The arm portion 28 may be a columnar shape other than a cylinder, such as a rectangular prism. As long as the arm portion 28 is continuous from the bracket 30b to the nozzle portion 29, the center line of the arm portion 28 may be a straight line extending horizontally from the base of the arm portion 28 to the tip 28d of the arm portion 28, or may include a portion extending horizontally toward the tip 28d of the arm portion 28 and a portion curved horizontally or downward. FIG. 4 shows an example in which the arm portion 28 includes a horizontal portion 28h extending horizontally toward the tip 28d of the arm portion 28 and a corner portion 28c curved downward from the tip of the horizontal portion 28h. In this example, when the arm portion 28 is viewed in a horizontal direction perpendicular to the center line of the arm portion 28, the corner portion 28c has an arc shape that protrudes obliquely upward.

[0047] 4, the nozzle portion 29 includes a discharge port 30p that discharges the treatment liquid downward, a lower surface 29L in which the discharge port 30p opens, and a cylindrical outer peripheral surface 29o that extends upward from the outer edge of the lower surface 29L. The thickness of the outer peripheral surface 29o of the nozzle portion 29 corresponds to the thickness of the nozzle portion 29. The center line of the nozzle portion 29 corresponds to the center line of the outer peripheral surface 29o of the nozzle portion 29. The outer edge of the discharge port 30p surrounds the center line of the nozzle portion 29. The shape of the discharge port 30p may be a circle, a ring, or some other shape.

[0048] 4 shows an example in which the treatment liquid nozzle 30 includes a resin tube 30t that guides the treatment liquid, a cylindrical core 30c that surrounds the resin tube 30t, and a cylindrical resin coating 30r that surrounds the core 30c. The resin tube 30t forms a flow path extending along the treatment liquid nozzle 30. The treatment liquid guided by a pipe such as the chemical liquid pipe 31p (see FIG. 2) is supplied into the resin tube 30t. A tip 30d of the resin tube 30t protrudes downward from the core 30c and the resin coating 30r. The lower surface of the tip 30d of the resin tube 30t corresponds to the lower surface 29L of the nozzle portion 29. The discharge port 30p opens at the lower surface of the tip 30d of the resin tube 30t.

[0049] The nozzle moving unit 30m moves the three processing liquid nozzles 30 horizontally between a processing position (position indicated by two-dot chain lines in FIG. 3 ) where the processing liquid ejected from any of the three processing liquid nozzles 30 is supplied to the upper surface of the substrate W, and a standby position (position indicated by solid lines in FIG. 3 ) where the three processing liquid nozzles 30 are positioned around the processing cup 21 in a plan view. The nozzle moving unit 30m rotates the three processing liquid nozzles 30 about a vertical rotation axis A2 located outside the processing cup 21, thereby moving the three processing liquid nozzles 30 horizontally along an arc-shaped path passing through the center of the substrate W in a plan view. The nozzle moving unit 30m may horizontally translate the three processing liquid nozzles 30 instead of rotating them.

[0050] The nozzle movement unit 30m includes a horizontal actuator 30h that generates power to move the three processing liquid nozzles 30 horizontally, and a vertical actuator 30v that generates power to move the three processing liquid nozzles 30 vertically. The horizontal actuator 30h moves the three processing liquid nozzles 30 horizontally between a processing position and a standby upper position. The vertical actuator 30v moves the three processing liquid nozzles 30 vertically between a standby upper position (position indicated by a solid line in FIG. 8 ) and a standby lower position (position indicated by a two-dot chain line in FIG. 8 ). The standby lower position is a position directly below the standby upper position. Both the standby upper position and the standby lower position are standby positions.

[0051] An actuator is a device that converts driving energy, such as electrical, fluid, magnetic, thermal, or chemical energy, into mechanical work. Actuators include electric motors (rotary motors), linear motors, air cylinders, and other devices. When an actuator is an electric motor that translates an object horizontally, the rotation of the actuator may be converted into linear motion of the object using a motion converter such as a ball screw and ball nut. The contents of this paragraph also apply to actuators other than the horizontal actuator 30h and the vertical actuator 30v.

[0052] 3 , the processing unit 2 includes a standby pot 44 that receives the processing liquid discharged downward from the three processing liquid nozzles 30 positioned at the lower standby position. The standby pot 44 is disposed outside the processing cup 21. The upper standby position and the lower standby position are positions where the three processing liquid nozzles 30 overlap with the standby pot 44 in a plan view. The standby pot 44 is disposed below the three processing liquid nozzles 30 positioned at the upper standby position. When the three processing liquid nozzles 30 move downward in parallel from the upper standby position to the lower standby position, the three processing liquid nozzles 30 are inserted into the standby pot 44 through openings provided in the upper surface of the standby pot 44.

[0053] Next, the electrical configuration of the substrate processing apparatus 1 will be described.

[0054] 5 is a block diagram showing the electrical configuration of the substrate processing apparatus 1. The control device 3 includes at least one computer. The computer includes a computer main body 3a and a peripheral device 3d connected to the computer main body 3a. The computer main body 3a includes a CPU 3b (central processing unit) that executes various commands and a memory 3c that stores information. The peripheral device 3d includes a storage 3e that stores information to be transmitted and received between the memory 3c, such as a program P, a reader 3f that reads information from removable media RM, and a communication device 3g that communicates with other devices, such as a host computer. The memory 3c and the storage 3e are both examples of storage devices that store information to be transmitted and received between the CPU 3b and the peripheral device 3d.

[0055] The control device 3 is connected to an input device and a display device. The input device is operated when an operator such as a user or a maintenance technician inputs information into the substrate processing apparatus 1. The information is displayed on the screen of the display device. The input device may be any of a keyboard, a pointing device, and a touch panel, or may be other devices. The substrate processing apparatus 1 may be provided with a touch panel display that serves as both an input device and a display device.

[0056] The CPU 3b executes a program P stored in the storage 3e. The program P in the storage 3e may be one that has been pre-installed in the control device 3, one that has been sent from a removable medium RM to the storage 3e via the reader 3f, or one that has been sent from an external device such as a host computer to the storage 3e via the communication device 3g.

[0057] The memory 3c is a volatile memory that retains its memory only when power is supplied. The storage 3e and the removable medium RM are non-volatile memories that retain their memory even when power is not supplied. The storage 3e is, for example, a magnetic storage device such as a hard disk drive. The removable medium RM is, for example, an optical disk such as a compact disk or a semiconductor memory such as a memory card. The removable medium RM is an example of a computer-readable recording medium on which the program P is recorded. The removable medium RM is a non-transitory tangible recording medium.

[0058] The storage 3e stores a plurality of recipes. A recipe is information that defines the processing content, processing conditions, and processing procedure of a substrate W. The plurality of recipes differ from one another in at least one of the processing content, processing conditions, and processing procedure of a substrate W. The control device 3 controls the substrate processing apparatus 1 so that the substrate W is processed in accordance with the recipe specified by the host computer. The control device 3 is programmed to execute the following steps.

[0059] Next, an example of processing of the substrate W will be described.

[0060] 6 is a process diagram for explaining an example of processing of a substrate W performed by the substrate processing apparatus 1. In the following, reference will be made to FIGS. 1A, 2, and 6. FIG.

[0061] When a substrate W is to be processed, the indexer robot IR takes the substrate W out of the carrier CA on one of the load ports LP. The center robot CR carries the substrate W taken out by the indexer robot IR into one of the processing units 2 and places it on the spin chuck 10. Thereafter, a plurality of chuck pins 11 are pressed horizontally against the edge surface of the substrate W, and the spin motor 14 starts to rotate. This starts the rotation of the substrate W.

[0062] After the center robot CR moves the hand Hc out of the processing unit 2, the nozzle moving unit 30m moves the three processing liquid nozzles 30 to the processing positions. Then, the chemical liquid valve 31v is opened. When the chemical liquid valve 31v is opened, the chemical liquid nozzle 31 discharges the chemical liquid toward the upper surface of the rotating substrate W. This forms a liquid film of the chemical liquid that covers the entire upper surface of the substrate W (step S1 in FIG. 6).

[0063] When the chemical liquid nozzles 31 are discharging the chemical liquid, the nozzle moving unit 30m may move the three processing liquid nozzles 30 so that the collision position of the chemical liquid against the upper surface of the substrate W passes through the center and the outer periphery, or may keep the three processing liquid nozzles 30 stationary so that the collision position is stationary at the center. In the former case, the nozzle moving unit 30m may horizontally move the three processing liquid nozzles 30 between a center position (position shown in FIG. 2 ) where the chemical liquid discharged from the chemical liquid nozzles 31 collides with the center of the upper surface of the substrate W, and an edge position where the chemical liquid discharged from the chemical liquid nozzles 31 collides with the outer periphery of the upper surface of the substrate W. The center position and the edge position are both processing positions. Whether or not the collision position is moved is the same for other processing liquids.

[0064] When a predetermined time has elapsed since the chemical liquid valve 31v was opened, the chemical liquid valve 31v is closed and the rinse liquid valve 32v is opened. In response, the rinse liquid nozzle 32 ejects pure water, an example of a rinse liquid, toward the upper surface of the rotating substrate W. As a result, the chemical liquid on the substrate W is replaced with pure water, and a liquid film of pure water is formed covering the entire upper surface of the substrate W (step S2 in FIG. 6 ). Thereafter, the rinse liquid valve 32v is closed and the solvent valve 33v is opened. In response, the solvent nozzle 33 ejects IPA, an example of an organic solvent, toward the upper surface of the rotating substrate W. As a result, the pure water on the substrate W is replaced with IPA, and a liquid film of IPA is formed covering the entire upper surface of the substrate W (step S3 in FIG. 6 ). Thereafter, the solvent valve 33v is closed.

[0065] When the solvent valve 33v is closed, the spin motor 14 rotates the substrate W held by the multiple chuck pins 11 at a high rotational speed (e.g., several thousand rpm). This removes the liquid from the substrate W and dries the substrate W (step S4 in FIG. 6). After the substrate W has dried, the spin motor 14 stops and the multiple chuck pins 11 move away from the edge of the substrate W. This stops the rotation of the substrate W and releases the substrate W from its hold. The center robot CR then unloads the substrate W from the processing unit 2. The indexer robot IR loads the substrate W unloaded by the center robot CR into a carrier CA on one of the load ports LP.

[0066] The nozzle moving unit 30m moves the three processing liquid nozzles 30 to the lower standby position via the upper standby position after the discharge of the processing liquid, such as IPA, that is last supplied to the substrate W has stopped. The nozzle moving unit 30m may cause the three processing liquid nozzles 30 to reach positions where the three processing liquid nozzles 30 do not overlap the substrate W in a plan view before starting to dry the substrate W, i.e., before starting to accelerate the substrate W, or may cause the three processing liquid nozzles 30 to reach the same positions after starting to dry the substrate W.

[0067] In this manner, one substrate W is treated with a treatment liquid such as a chemical solution. The control device 3 controls the indexer robot IR and the like to cause the substrate treatment apparatus 1 to repeat the above-described series of operations. In this manner, a plurality of substrates W are treated one by one.

[0068] Next, a description will be given of the cleaning nozzle 51 that cleans the processing liquid nozzle 30 and the drying nozzle that dries the processing liquid nozzle 30. First, the cleaning nozzle 51 will be described.

[0069] Fig. 7 is a schematic plan view showing the processing liquid nozzle 30, the cleaning nozzle 51, the first drying nozzle 56, and the second drying nozzle 61. Fig. 8 is a schematic view showing the processing liquid nozzle 30, the cleaning nozzle 51, the first drying nozzle 56, and the second drying nozzle 61 viewed horizontally. Fig. 7 shows the processing liquid nozzle 30 positioned at the upper standby position. Fig. 8 shows the processing liquid nozzle 30 positioned at the upper standby position by a solid line, and the processing liquid nozzle 30 positioned at the lower standby position by a two-dot chain line.

[0070] 8 , the processing unit 2 includes a cleaning nozzle 51 that ejects pure water, which is an example of a cleaning liquid, toward the three processing liquid nozzles 30. The cleaning nozzle 51 is connected to a cleaning liquid pipe 54 to which a cleaning liquid valve 55 is attached. The cleaning nozzle 51 includes a plurality of cleaning liquid ejection ports 52 that eject pure water toward the three processing liquid nozzles 30, and a cleaning liquid supply path 53 that supplies pure water to the plurality of cleaning liquid ejection ports 52.

[0071] The cleaning nozzle 51 is disposed above the three processing liquid nozzles 30 positioned at the upper standby position. The three processing liquid nozzles 30 pass below the cleaning nozzle 51. As shown in FIG. 7 , the cleaning nozzle 51 is disposed to the side of the three processing liquid nozzles 30 positioned at the upper standby position in a plan view. The cleaning nozzle 51 extends in an axial direction (left-right direction in FIG. 7 ) that is parallel to the three processing liquid nozzles 30 positioned at the upper standby position in a plan view. The cleaning nozzle 51 is disposed on the processing cup 21 side of the three processing liquid nozzles 30 positioned at the upper standby position in a plan view (see FIG. 3 ).

[0072] The cleaning nozzle 51 is a shower nozzle that discharges pure water obliquely downward from multiple cleaning liquid discharge ports 52. The multiple cleaning liquid discharge ports 52 are aligned in a straight line at equal intervals in the axial direction of the cleaning nozzle 51. By discharging the pure water, the cleaning nozzle 51 forms a sheet-like liquid flow that flows obliquely downward from the cleaning nozzle 51. The cleaning nozzle 51 may discharge the pure water so that the thickness of the liquid flow is constant, or may discharge the pure water so that the thickness of the liquid flow increases with increasing distance from the cleaning nozzle 51.

[0073] When the three processing liquid nozzles 30 are positioned at any position from the upper standby position to the lower standby position, the horizontal portion 28h, the corner portion 28c, and the nozzle portion 29 of the chemical liquid nozzle 31 are visible from the cleaning nozzle 51. On the other hand, when viewed from the cleaning nozzle 51, the horizontal portion 28h, the corner portion 28c, and the nozzle portion 29 of the rinse liquid nozzle 32 and the horizontal portion 28h, the corner portion 28c, and the nozzle portion 29 of the solvent nozzle 33 are hidden by the horizontal portion 28h, the corner portion 28c, and the nozzle portion 29 of the chemical liquid nozzle 31.

[0074] When cleaning the three processing liquid nozzles 30 with the pure water discharged from the cleaning nozzle 51, the control device 3 controls the nozzle movement unit 30m to raise and lower the three processing liquid nozzles 30 between the upper standby position and the lower standby position. At the upper standby position, the pure water discharged from the cleaning nozzle 51 mainly hits the horizontal portion 28h of the chemical liquid nozzle 31. At the lower standby position, the pure water discharged from the cleaning nozzle 51 mainly hits the horizontal portion 28h of the solvent nozzle 33. As the three processing liquid nozzles 30 move between the upper standby position and the lower standby position, the three processing liquid nozzles 30 sequentially pass through the sheet-like liquid flow. As a result, the pure water discharged from the cleaning nozzle 51 is supplied to the horizontal portions 28h of all of the processing liquid nozzles 30.

[0075] Next, the first drying nozzle 56 that dries the nozzle portions 29 of the three processing liquid nozzles 30 will be described.

[0076] 7 , the first drying nozzle 56 includes a plurality of first gas outlets 57 that discharge nitrogen gas, which is an example of a drying gas, into the waiting pot 44, and a first gas supply path 58 that supplies nitrogen gas to the plurality of first gas outlets 57. The first gas supply path 58 is connected to a first gas pipe 59 to which a first gas valve 60 is attached.

[0077] 8, the standby pot 44 includes a cylindrical peripheral wall 45 that surrounds the nozzle portions 29 of the three processing liquid nozzles 30 that are positioned at the lower standby position (the position indicated by the two-dot chain line in FIG. 8), and a bottom wall 46 that closes the lower end of the peripheral wall 45. The bottom surface of the standby pot 44 extends obliquely downward toward a discharge port 47 (see FIG. 7) that opens at the bottom surface of the standby pot 44. The liquid in the standby pot 44 is discharged from the discharge port 47.

[0078] The first gas discharge port 57 opens on the inner peripheral surface of the waiting pot 44. The multiple first gas discharge ports 57 are arranged in the circumferential direction of the waiting pot 44. The multiple first gas discharge ports 57 discharge nitrogen gas in two or more directions that are different from each other in a plan view. The first gas supply path 58 is provided inside the peripheral wall 45 of the waiting pot 44. As shown in FIG. 7 , the first gas supply path 58 includes a first gas flow path 58a that guides the nitrogen gas supplied to the multiple first gas discharge ports 57, two second gas flow paths 58b branching from the first gas flow path 58a, and multiple third gas flow paths 58c branching from the two second gas flow paths 58b.

[0079] When the first gas valve 60 is opened, multiple air currents flowing inward from the multiple first gas discharge ports 57 are formed in the waiting pot 44. The first gas discharge ports 57 discharge nitrogen gas supplied from the first gas supply path 58, thereby forming linear air currents flowing inward from the first gas discharge ports 57. The third gas flow path 58c of the first gas supply path 58 extends obliquely downward toward the first gas discharge ports 57. The first gas discharge ports 57 discharge the nitrogen gas obliquely downward. The first gas discharge ports 57 may discharge the nitrogen gas horizontally or obliquely upward.

[0080] Next, the second drying nozzle 61 that dries the horizontal portions 28h of the three processing liquid nozzles 30 will be described.

[0081] 8 , the processing unit 2 includes a second drying nozzle 61 that discharges nitrogen gas, which is an example of a drying gas, toward the three processing liquid nozzles 30. The second drying nozzle 61 is connected to a second gas pipe 64 to which a second gas valve 65 is attached. The second drying nozzle 61 includes a plurality of (e.g., two) second gas discharge ports 62 that discharge nitrogen gas toward the three processing liquid nozzles 30, and a second gas supply path 63 that supplies nitrogen gas to the plurality of second gas discharge ports 62.

[0082] As shown in Fig. 7, the second gas discharge port 62 horizontally faces the nozzle portion 29 of the chemical liquid nozzle 31 that is positioned at the upper standby position. The second gas discharge port 62 is located on the opposite side of the nozzle portion 29 from the horizontal portion 28h. As shown in Fig. 8, when the three processing liquid nozzles 30 are positioned at the upper standby position, the upper second gas discharge port 62 is located at the same height as the horizontal portion 28h, and the lower second gas discharge port 62 is located at the same height as the corner portion 28c. The second gas discharge port 62 is located above the standby pot 44. The second drying nozzles 61 are located around the processing cup 21 in a plan view (see Fig. 3).

[0083] The second drying nozzle 61 may be a nozzle that forms a linear airflow, or may be a nozzle that forms a conical airflow whose diameter increases with increasing distance from the second drying nozzle 61. When the three processing liquid nozzles 30 are located in the upper standby position, the nitrogen gas discharged from the upper second gas discharge port 62 hits the corner portion 28 c of the chemical liquid nozzle 31 and flows along the upper edge of the horizontal portion 28 h of the chemical liquid nozzle 31 toward the base of the horizontal portion 28 h. The nitrogen gas discharged from the lower second gas discharge port 62 hits the corner portion 28 c of the chemical liquid nozzle 31 and flows along the lower edge of the horizontal portion 28 h of the chemical liquid nozzle 31 toward the base of the horizontal portion 28 h.

[0084] When drying the three processing liquid nozzles 30 with nitrogen gas discharged from the second drying nozzle 61, the control device 3 controls the nozzle movement unit 30m to move the three processing liquid nozzles 30 horizontally around the rotation axis A2 between two turning positions. Both of the two turning positions are at the same height as the processing position and the upper standby position. The first turning position (the position shown in FIG. 7) is, for example, the upper standby position, and the second turning position is, for example, a position between the processing position and the upper standby position.

[0085] At the first turning position, the nitrogen gas discharged from the second drying nozzle 61 mainly hits the horizontal portion 28 h and the corner portion 28 c of the chemical solution nozzle 31. At the second turning position, the nitrogen gas discharged from the second drying nozzle 61 mainly hits the horizontal portion 28 h and the corner portion 28 c of the solvent nozzle 33. When the three processing liquid nozzles 30 move between the first turning position and the second turning position, the position at which the nitrogen gas hits the three processing liquid nozzles 30 moves horizontally. As a result, the nitrogen gas discharged from the second drying nozzle 61 is supplied to the horizontal portion 28 h and the corner portion 28 c of all of the processing liquid nozzles 30.

[0086] When cleaning and drying the three processing liquid nozzles 30, the three processing liquid nozzles 30 are raised and lowered between the upper standby position and the lower standby position while pure water is being discharged from the cleaning nozzle 51. As a result, the pure water discharged from the cleaning nozzle 51 is supplied to all of the processing liquid nozzles 30. After the cleaning nozzle 51 stops discharging the pure water, the three processing liquid nozzles 30 are raised and lowered between the upper standby position and the lower standby position while nitrogen gas is being discharged from the first drying nozzle 56. Thereafter, the three processing liquid nozzles 30 are horizontally reciprocated between the two turning positions while nitrogen gas is being discharged from the second drying nozzle 61. As a result, the three processing liquid nozzles 30 cleaned with pure water, which is an example of a cleaning liquid, are dried. The supply of nitrogen gas from the first drying nozzle 56 to the three processing liquid nozzles 30 may be performed after the supply of nitrogen gas from the second drying nozzle 61 to the three processing liquid nozzles 30.

[0087] Next, the outer surface 30s of the processing liquid nozzle 30 will be described.

[0088] Fig. 9 is a schematic diagram showing an example of a water-repellent surface 72 and a mirror surface 71 provided on the outer surface 30s of the processing liquid nozzle 30. Fig. 10 is a schematic cross-sectional view showing an example of a droplet contacting a smooth surface. Fig. 11 is a schematic cross-sectional view showing an example of a droplet contacting a rough surface in a Wenzel state. Fig. 12 is a schematic cross-sectional view showing an example of a droplet contacting a rough surface in a Cassie-Baxter state.

[0089] At least a portion of the outer surface 30s of the processing liquid nozzle 30 is made of a resin such as a fluororesin. Therefore, at least one of the lower surface 29L of the nozzle portion 29, the outer peripheral surface 29o of the nozzle portion 29, and the outer peripheral surface 28o of the arm portion 28 is made of a resin. The fluororesin may be PTFE (Polytetrafluoroethylene) or PFA (Perfluoroalkoxyalkane), or may be other materials. The entire outer surface 30s of the processing liquid nozzle 30 may be made of the same material, or a portion of the outer surface 30s of the processing liquid nozzle 30 may be made of a material different from the remaining portion of the outer surface 30s of the processing liquid nozzle 30.

[0090] 9 , the outer surface 30s of the processing liquid nozzle 30 includes a water-repellent surface 72 and a mirror surface 71. The mirror surface 71 is a surface that has been subjected to a mirror finish to reduce surface roughness. The mirror finish may be a polishing process or a process other than this. The water-repellent surface 72 is a rough surface that has a greater surface roughness than the mirror surface 71. In other words, the mirror surface 71 is a smooth surface that has a smaller surface roughness than the water-repellent surface 72.

[0091] The entire outer surface 30s of the processing liquid nozzle 30 may be the water-repellent surface 72, or only a portion of the outer surface 30s of the processing liquid nozzle 30 may be the water-repellent surface 72. In the latter case, the entire remaining portion of the outer surface 30s of the processing liquid nozzle 30 may be the mirror surface 71, or only a portion of the remaining portion of the outer surface 30s of the processing liquid nozzle 30 may be the mirror surface 71. Figure 9 shows an example in which the entire outer surface of the arm portion 28, including the outer peripheral surface 28o of the arm portion 28, is the water-repellent surface 72, and the entire outer surface of the nozzle portion 29, including the lower surface 29L and the outer peripheral surface 29o of the nozzle portion 29, is the mirror surface 71. In Figure 9, the area surrounded by a two-dot chain rectangle B1 indicates the area where the mirror surface 71 is provided, and the area surrounded by a two-dot chain rectangle B2 indicates the area where the water-repellent surface 72 is provided.

[0092] The water-repellent surface 72 is a solid surface that has been subjected to a water-repellent treatment that increases the contact angle of water. The water-repellent treatment may be at least one of cutting, laser processing, plastic processing, extrusion molding, blasting, and etching, or may be other than these.

[0093] The cutting process may be at least one of lathe processing and milling processing, or may be other processes. The blasting process is a process in which solid particles are collided with the surface of an object (such as shot blasting). The etching process is a process in which the surface of an object is corroded with a chemical. The water-repellent process may be a process in which the irregularities on the surface of a mold are transferred to the object. In this case, the water-repellent process may be at least one of plastic processing and extrusion molding, or may be other processes.

[0094] The water-repellent surface 72 is an uneven surface provided with a plurality of recesses 72u and a plurality of protrusions 72h. The recesses 72u are recessed from the tips 72d of the protrusions 72h. The protrusions 72h protrude from the bottoms 72b of the recesses 72u. The bottoms 72b of the recesses 72u correspond to the bases of the protrusions 72h. The tips 72d of the protrusions 72h correspond to the opening ends of the recesses 72u. The tips 72d of two adjacent protrusions 72h form the entrance of the recess 72u located between them.

[0095] The convex portion 72h may be linear with a depth greater than its width, or may be dot-shaped with a depth equal to or approximately equal to its width, or may have other shapes. The same applies to the concave portion 72u. The cross section of the convex portion 72h may be rectangular, square, triangular, inverted triangle, trapezoid, inverted trapezoid, or semicircular, or may have other shapes. The same applies to the cross section of the concave portion 72u. Figure 9 shows an example in which the cross sections of the convex portion 72h and the concave portion 72u are rectangular. The height of the convex portion 72h (length in the vertical direction in Figure 9) may be uniform or non-uniform. The same applies to the depth of the concave portion 72u. The height of the convex portion 72h may be equal to or different from the width of the convex portion 72h (length in the horizontal direction in Figure 9). The depth of the concave portion 72u may be equal to or different from the width of the concave portion 72u.

[0096] If the water contact angle is less than 90 degrees, the solid surface is said to be hydrophilic. If the water contact angle is 90 degrees or greater, the solid surface is said to be water-repellent or hydrophobic. If the water contact angle is 150 degrees or greater, the solid surface is said to be super-water-repellent. The water contact angle with a smooth fluororesin surface may be greater than 90 degrees or less than 90 degrees. The water contact angle with a smooth PTFE surface is said to be 104 to 114 degrees. The water contact angle with a smooth PFA surface is said to be 105 to 118 degrees. The water contact angle with the water-repellent surface 72 may be 119 degrees or greater, preferably 150 degrees or greater. The water contact angle with the mirror surface 71 may be greater than 90 degrees or less than 90 degrees. Figure 10 shows an example of the former.

[0097] As shown in FIG. 12 , when a water droplet is placed on the horizontal water-repellent surface 72 under normal temperature and pressure (room temperature and 1 atmosphere), the bottom 72b of the recess 72u is separated from the water droplet, and the tip 72d of the protrusion 72h comes into contact with the water droplet. In other words, the water-repellent surface 72 is a surface that enters the Cassie-Baxter state when a water droplet is placed on the horizontal water-repellent surface 72 under normal temperature and pressure. As shown in FIG. 11 , the water-repellent surface 72 may be a surface that enters the Wenzel state when a water droplet is placed on the horizontal water-repellent surface 72 under normal temperature and pressure. Room temperature is, for example, a constant or approximately constant temperature within a range of 10 to 30°C.

[0098] The Cassie-Baxter model and the Wenzel model are models used to explain wetting of rough surfaces. As shown in Figure 11, in the Wenzel state (hereinafter also referred to as the W state), a water droplet on a horizontal rough surface penetrates into the depressions. In contrast, as shown in Figure 12, in the Cassie-Baxter state (hereinafter also referred to as the CB state), the depressions 72u are filled with air, and the water droplets are supported by the tips 72d of the protrusions 72h.

[0099] Whether a water droplet on a rough surface adopts the W state or the CB state is influenced by factors such as the surface tension of the liquid, the surface free energy of the rough surface (solid), and the surface texture of the rough surface. It is thought that the higher the surface tension of the liquid and the lower the surface free energy of the rough surface (the more water-repellent the rough surface), the more likely the water droplet on the rough surface will adopt the CB state.

[0100] The outer surface 30s of the treatment liquid nozzle 30 is made of a water-repellent material that has a contact angle of water exceeding 90 degrees with respect to a horizontal, smooth surface. Therefore, if the surface properties of the water-repellent surface 72 satisfy certain conditions, a water droplet will contact the horizontal water-repellent surface 72 in a CB state. In other words, when a water droplet is placed on the horizontal water-repellent surface 72 under an environment of room temperature and normal pressure, the tip 72d of the convex portion 72h will contact the water droplet with the bottom 72b of the concave portion 72u separated from the water droplet. The water-repellent treatment described above is a treatment that changes the outer surface 30s of the treatment liquid nozzle 30 so that the water droplet will contact the water-repellent surface 72 in a CB state.

[0101] 11 and 12, when a water droplet contacts the horizontal water-repellent surface 72 in the CB state and when a water droplet contacts the horizontal water-repellent surface 72 in the W state, the contact area between the water droplet and the water-repellent surface 72 is smaller when the water droplet contacts the horizontal water-repellent surface 72 in the CB state. Furthermore, the contact angle of water with the water-repellent surface 72 is larger when the water droplet contacts the horizontal water-repellent surface 72 in the CB state.

[0102] When a liquid such as a cleaning liquid comes into contact with the water-repellent surface 72, the liquid flows downward along the water-repellent surface 72 and falls from the water-repellent surface 72. This allows the liquid to be quickly discharged from the water-repellent surface 72. Even if some liquid remains, this liquid does not form a liquid film that covers part of the water-repellent surface 72, but rather forms multiple hemispherical droplets dispersed on the water-repellent surface 72. When vibrations are applied to the water-repellent surface 72 or when an air current hits the droplets, the droplets are discharged from the water-repellent surface 72. Even if the droplets are not discharged from the water-repellent surface 72, because only a small amount of liquid remains on the water-repellent surface 72, the droplets disappear from the water-repellent surface 72 in a short period of time due to evaporation of the liquid. This allows the amount of liquid remaining on the water-repellent surface 72 to be reduced to zero or almost zero.

[0103] On the other hand, because the mirror surface 71 is smooth, when liquid comes into contact with the mirror surface 71, the liquid flows downward along the mirror surface 71 and falls off the mirror surface 71. Therefore, only relatively small droplets or liquid films remain on the mirror surface 71. This means that little liquid remains on the mirror surface 71. The mirror surface 71 is a smooth surface with no or very few indentations such as scratches or grooves. The grooves on a rough surface are deeper than the indentations on the mirror surface 71. Liquid droplets or liquid films on a rough surface may accumulate in the grooves of the rough surface and flow along these grooves. This phenomenon is less likely to occur on the mirror surface 71 than on a rough surface. Furthermore, because the liquid droplets or liquid films remaining on the mirror surface 71 are relatively small, they are held to the mirror surface 71 by forces acting between the liquid droplets or liquid film and the mirror surface 71 (e.g., intermolecular forces and frictional forces). This reduces the amount of liquid remaining on the mirror surface 71 and makes it more difficult for the remaining liquid to fall off the mirror surface 71.

[0104] When the processing liquid nozzle 30 is moved from the standby position to the processing position with a liquid such as a cleaning liquid adhering to the outer surface 30s of the processing liquid nozzle 30, the liquid may fall from the processing liquid nozzle 30 before or when the processing liquid nozzle 30 reaches the processing position. When droplets falling from the processing liquid nozzle 30 collide with the upper surface of the substrate W before it is covered with the liquid such as the processing liquid, a pattern like a watermark may be left at that position. When droplets falling from the processing liquid nozzle 30 collide with a liquid film covering the upper surface of the substrate W, such a pattern may also be left on the upper surface of the substrate W. These patterns may cause a deterioration in the quality of the substrate W (particularly the cleanliness of the substrate W).

[0105] Liquid is unlikely to remain on the water-repellent surface 72. Even if liquid remains on the mirror surface 71, it is only a small amount. Therefore, when the outer surface 30s of the processing liquid nozzle 30 located at the standby position is dried with a dry gas, liquid such as a cleaning liquid is unlikely to remain on the outer surface 30s of the processing liquid nozzle 30. Even if some cleaning liquid remains on the outer surface 30s of the processing liquid nozzle 30, the amount of remaining cleaning liquid is so small that it evaporates and disappears from the outer surface 30s of the processing liquid nozzle 30 before the processing liquid nozzle 30 is moved from the standby position. Therefore, when the processing liquid nozzle 30 is moved toward the processing position after being dried at the standby position, it is possible to prevent droplets from falling from the outer surface 30s of the processing liquid nozzle 30 toward the upper surface of the substrate W. This makes it possible to prevent deterioration in the quality of the substrate W.

[0106] Next, the mist and droplets that are generated when the treatment liquid nozzle 30 ejects the treatment liquid will be described.

[0107] Fig. 13 is a schematic diagram for explaining the mist and droplets generated when the processing liquid nozzle 30 discharges the processing liquid. Fig. 14 is a schematic diagram showing a state in which the processing liquid nozzle 30 is being moved from the processing position to the standby position while drying the substrate W. The multiple dots near the nozzle portion 29 in Fig. 13 represent mist, and the teardrop-shaped particles in Fig. 13 represent droplets. The straight arrows in Fig. 13 represent the direction in which the mist or droplets move.

[0108] 13, when the processing liquid nozzle 30 moves to the processing position and starts supplying the processing liquid to the substrate W, mist and droplets are generated. Specifically, when the processing liquid nozzle 30 ejects the processing liquid toward the upper surface of the rotating substrate W, mist is generated from the ejection port 30p of the processing liquid nozzle 30 (see FIG. 14). Mist is also generated when the processing liquid collides with the upper surface of the substrate W or with the liquid on the substrate W. Gases such as fumes may also be generated from the liquid on the substrate W.

[0109] The processing liquid discharged from the processing liquid nozzle 30 flows outward along the upper surface of the substrate W and splashes from the outer periphery of the substrate W. At this time, multiple droplets are generated. Most of the droplets splash horizontally or diagonally downward from the outer periphery of the substrate W, but some droplets splash diagonally upward from the outer periphery of the substrate W. Such droplets are particularly likely to be generated when the processing liquid collides with the chuck pin 11. The droplets splashed from the outer periphery of the substrate W collide with the inner circumferential surface of the guard 24. Therefore, some droplets bounce off the inner circumferential surface of the guard 24 toward the substrate W.

[0110] Comparing the nozzle part 29 with the arm part 28, mist generated by the discharge or collision of the processing liquid is likely to come into contact with the nozzle part 29. Comparing the nozzle part 29 with the arm part 28, when the nozzle part 29 is disposed at the center position shown in Fig. 13, droplets scattered from the outer periphery of the substrate W or the inner circumferential surface of the guard 24 are likely to come into contact with the arm part 28. When the processing liquid nozzle 30 is moved to the edge position, droplets also come into contact with the nozzle part 29, but because the time that the processing liquid nozzle 30 is disposed at or near the edge position is short, only a small amount of droplets come into contact with the nozzle part 29.

[0111] The droplets adhering to the outer surface 30s of the processing liquid nozzle 30 fall from the processing liquid nozzle 30 or combine with other droplets or particles of other liquid on the outer surface 30s of the processing liquid nozzle 30. The liquid particles constituting the mist also combine with other droplets or particles of other liquid on the outer surface 30s of the processing liquid nozzle 30. Larger droplets fall from the processing liquid nozzle 30. However, there are cases where such falling of droplets is undesirable. For example, if drying of the substrate W starts before the processing liquid nozzle 30 reaches the standby position, droplets may fall on the exposed portion of the top surface of the substrate W from which the liquid has run out.

[0112] If at least one of the water-repellent surface 72 and the mirror surface 71 is provided on the outer surface 30s of the processing liquid nozzle 30, the mist and droplets immediately fall from the outer surface 30s of the processing liquid nozzle 30, thereby reducing the amount of liquid remaining on the outer surface 30s of the processing liquid nozzle 30 to zero or almost zero. If only a small amount of liquid remains on the outer surface 30s of the processing liquid nozzle 30, the liquid evaporates on the outer surface 30s of the processing liquid nozzle 30, or moves toward the standby position together with the processing liquid nozzle 30 without falling from the outer surface 30s of the processing liquid nozzle 30. Therefore, when the processing liquid nozzle 30 is moved from the processing position to the standby position, droplets can be prevented from falling from the outer surface 30s of the processing liquid nozzle 30 onto the upper surface of the substrate W.

[0113] The multiple dots adhering to the nozzle portion 29 in Fig. 14 represent mist. Fig. 14 shows a state in which the processing liquid nozzle 30 is moving from the processing position to the standby position with the mist adhering to the nozzle portion 29. As shown in Fig. 14, even if the processing liquid nozzle 30 is moved from the processing position to the standby position while the substrate W is being dried, all or almost all of the mist does not fall from the nozzle portion 29 but moves toward the standby position together with the nozzle portion 29. This reduces the probability that mist or droplets will fall on the exposed portion of the top surface of the substrate W from which the liquid has run out.

[0114] Next, the effects of this embodiment will be described.

[0115] In this embodiment, the processing liquid is ejected from the nozzle portion 29 of the processing liquid nozzle 30 toward the upper surface of the substrate W. Mist and droplets of the processing liquid generated when the nozzle portion 29 ejects the processing liquid may come into contact with the processing liquid nozzle 30. At least a portion of the outer surface 30s of the processing liquid nozzle 30 is a water-repellent surface 72. The mist and droplets that come into contact with the water-repellent surface 72 immediately fall from the water-repellent surface 72. Therefore, the time it takes for a liquid such as the processing liquid to fall after coming into contact with the outer surface 30s of the processing liquid nozzle 30 can be shortened. This makes it possible to reduce the amount of liquid that unexpectedly falls from the processing liquid nozzle 30 onto the substrate W.

[0116] In this embodiment, all or part of the water-repellent surface 72 of the treatment liquid nozzle 30 is made uneven. The uneven surface includes a recess 72u at least partially filled with air and a protrusion 72h that contacts water (including an aqueous solution) that contacts the air in the recess 72u. Because at least a portion of the recess 72u is filled with air, the contact area between the water and the water-repellent surface 72 is reduced compared to when the entire recess 72u is filled with water. This reduces the force acting between the water and the water-repellent surface 72. Furthermore, according to the Cassie-Baxter equation, the contact angle of water with the water-repellent surface 72 is increased compared to when the recess 72u is filled with water (Wenzel state). This reduces the time it takes for water droplets or mist-like water to be discharged from the outer surface 30s of the treatment liquid nozzle 30.

[0117] In this embodiment, all or part of the water-repellent surface 72 is made of fluororesin. Fluororesin is a highly water-repellent material. Whether a liquid droplet on a rough surface adopts the Wenzel or Cassie-Baxter state depends on factors such as the surface tension of the liquid, the surface free energy of the rough surface (solid), and the surface properties of the rough surface. By making the water-repellent surface 72 out of a highly water-repellent material, it is possible to maintain a state in which at least a portion of the recesses 72u is filled with air. This reduces the contact area between the liquid and the water-repellent surface 72 while limiting the area in contact with the water-repellent surface 72.

[0118] In this embodiment, not only the water-repellent surface 72 but also a mirror surface 71 is provided on the outer surface 30s of the processing liquid nozzle 30. Because the mirror surface 71 is smooth, when liquid comes into contact with the mirror surface 71, the liquid flows downward along the mirror surface 71 and falls from the mirror surface 71. Therefore, only relatively small droplets or liquid films remain on the mirror surface 71. This means that little liquid remains on the mirror surface 71. The mirror surface 71 is a smooth surface with no or very few indentations such as scratches or grooves. The grooves on the rough surface are deeper than the indentations on the mirror surface 71. Liquid droplets or liquid films on the rough surface may accumulate in the grooves of the rough surface and flow along these grooves. This phenomenon is less likely to occur on the mirror surface 71 than on a rough surface. Furthermore, because the liquid droplets or liquid films remaining on the mirror surface 71 are relatively small, the liquid droplets or liquid films are held to the mirror surface 71 by forces (e.g., intermolecular forces and frictional forces) acting between the liquid droplets or liquid films and the mirror surface 71. This makes it possible to reduce the amount of liquid remaining on the mirror surface 71 and also makes it difficult for the remaining liquid to fall off the mirror surface 71.

[0119] In this embodiment, at least a portion of the outer surface of the nozzle portion 29 is formed as a mirror surface 71. In addition to the mist of the processing liquid being generated near the nozzle portion 29, the distance from the substrate W to the nozzle portion 29 is shorter than the distance from the substrate W to the arm portion 28. Therefore, the mist is more likely to come into contact with the nozzle portion 29 than with the arm portion 28. The contact angle of water with the mirror surface 71 is smaller than the contact angle of water with the water-repellent surface 72. When the mirror surface 71 is provided on the outer surface of the nozzle portion 29, liquid particles constituting the mist are less likely to fall from the outer surface of the nozzle portion 29 than when the water-repellent surface 72 is provided on the outer surface of the nozzle portion 29. Therefore, some liquid particles are retained on the mirror surface 71 without falling from the mirror surface 71. This reduces the amount of liquid falling from the nozzle portion 29 onto the substrate W. Contaminants may adhere to the outer surface of the nozzle portion 29 before or after the supply of the processing liquid to the substrate W is initiated. In such cases, the amount of contaminants falling from the nozzle portion 29 onto the upper surface of the substrate W along with the liquid can be reduced.

[0120] In this embodiment, the water-repellent surface 72 and the mirror surface 71 are arranged according to the size of liquid particles that come into contact with the outer surface 30s of the treatment liquid nozzle 30. Comparing the nozzle portion 29 and the arm portion 28, mist of the treatment liquid generated when the nozzle portion 29 is discharging the treatment liquid is likely to come into contact with the nozzle portion 29, and droplets of the treatment liquid generated when the nozzle portion 29 is discharging the treatment liquid are likely to come into contact with the arm portion 28. The mist is an aggregate of liquid particles that are smaller than droplets. By providing the mirror surface 71 on the outer surface of the nozzle portion 29 and the water-repellent surface 72 on the outer surface of the arm portion 28, it is possible to retain relatively small liquid particles in the nozzle portion 29 and quickly discharge relatively large liquid particles from the arm portion 28.

[0121] In this embodiment, the contact angle of water with the mirror surface 71 exceeds 90 degrees. According to Wenzel's equation, when the contact angle of liquid with a smooth surface exceeds 90 degrees, the contact angle of liquid with the smooth surface is smaller than the contact angle of liquid with a rough surface when comparing smooth and rough surfaces made of the same material. This means that when the contact angle of liquid with a smooth surface exceeds 90 degrees, changing the rough surface into a smooth surface reduces the contact angle of liquid. The mirror surface 71 is a smooth surface with no or very few indentations such as scratches or grooves. Therefore, the contact angle of water can be reduced compared to when the outer surface 30s of the processing liquid nozzle 30 is a rough surface, and the mirror surface 71 can increase the force with which the liquid is retained on the mirror surface 71.

[0122] In this embodiment, the processing liquid nozzle 30 is moved from the processing position to the standby position while the substrate W is being dried. When drying of the substrate W begins, an exposed portion of the upper surface of the substrate W is formed where the liquid has disappeared. If drying of the substrate W begins before the processing liquid nozzle 30 reaches the standby position, droplets of liquid falling from the processing liquid nozzle 30 may adhere to the exposed portion of the upper surface of the substrate W. Such adhesion may cause a deterioration in the quality of the substrate W (particularly the cleanliness of the substrate W). However, by providing a water-repellent surface 72 on the outer surface 30s of the processing liquid nozzle 30, the amount of liquid remaining on the outer surface 30s of the processing liquid nozzle 30 can be reduced. This reduces the number of droplets falling from the processing liquid nozzle 30 while the processing liquid nozzle 30 is being moved from the processing position to the standby position, thereby reducing the probability that the droplets will adhere to the exposed portion of the upper surface of the substrate W.

[0123] In this embodiment, the processing liquid nozzle 30 is moved between a processing position and a standby position. The cleaning nozzle 51 ejects a cleaning liquid toward the outer surface 30 s of the processing liquid nozzle 30 positioned at the standby position. The first drying nozzle 56 and the second drying nozzle 61, which are examples of drying nozzles, eject a drying gas toward the outer surface 30 s of the processing liquid nozzle 30 positioned at the standby position. This removes liquid such as a cleaning liquid from the processing liquid nozzle 30, drying the processing liquid nozzle 30. If the processing liquid nozzle 30 is not sufficiently dried, droplets may fall from the processing liquid nozzle 30 onto the substrate W when the processing liquid nozzle 30 is moved from the standby position to the processing position. However, by providing a water-repellent surface 72 on the outer surface 30 s of the processing liquid nozzle 30, the amount of liquid remaining on the outer surface 30 s of the processing liquid nozzle 30 can be reduced. Even if liquid remains on the outer surface 30 s of the processing liquid nozzle 30 after the supply of drying gas to the processing liquid nozzle 30 is stopped, the amount of remaining liquid is small, and therefore the liquid evaporates and disappears before the processing liquid nozzle 30 is moved to the processing position. This makes it possible to prevent droplets dropping from the processing liquid nozzle 30 from adhering to the upper surface of the substrate W before the processing liquid is supplied.

[0124] Next, another embodiment will be described.

[0125] All or part of the water-repellent surface 72 may be a water-repellent surface other than an uneven surface. For example, all or part of the water-repellent surface 72 may be a smooth surface having a higher water contact angle than the mirror surface 71. This smooth surface may be a coating layer made of a highly water-repellent material such as a fluororesin.

[0126] The nozzle portion 29 may be a separate member from the arm portion 28, but is fixed to the arm portion 28. Fig. 15 shows an example in which the nozzle portion 29 is fixed to the arm portion 28 in a state in which the nozzle portion 29 is inserted into a mounting hole provided at the tip of the arm portion 28.

[0127] If a member other than the arm portion 28 is provided to support the nozzle portion 29, the arm portion 28 may be omitted.

[0128] Instead of or in addition to providing the water-repellent surface 72 on the outer surface 30s of the processing liquid nozzle 30, which is a scan nozzle, the water-repellent surface 72 may be provided on the outer surface of a fixed nozzle that ejects the processing liquid downward toward the upper surface of the substrate W. In this case, the fixed nozzle may be disposed at a position that overlaps the substrate W in a plan view. For example, the fixed nozzle may be a central nozzle inserted into a hole that opens in the lower surface of a shielding plate that vertically faces the upper surface of the substrate W. When the water-repellent surface 72 is provided on the fixed nozzle, both the water-repellent surface 72 and the mirror surface 71 may be provided on the outer surface of the fixed nozzle.

[0129] The processing liquid nozzle 30 may be an external or internal mixing two-fluid nozzle that generates mist that scatters downward toward the upper surface of the substrate W by colliding liquid and gas.

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

[0131] Any two or more of the above-described features may be combined. Any two or more of the above-described steps may be combined.

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

Claims

1. A substrate processing apparatus comprising: a substrate holder that holds a substrate horizontally; and a processing liquid nozzle that ejects a processing liquid downward toward an upper surface of the substrate held by the substrate holder, wherein the outer surface of the processing liquid nozzle includes a water-repellent surface.

2. The substrate processing apparatus according to claim 1, wherein the water-repellent surface includes an uneven surface including a recess at least partially filled with air and a protrusion in contact with the water that is in contact with the air in the recess.

3. The substrate processing apparatus according to claim 2, wherein the uneven surface is made of a fluororesin.

4. The substrate processing apparatus according to claim 1, wherein the outer surface of the processing liquid nozzle includes the water-repellent surface and a mirror surface.

5. The substrate processing apparatus according to claim 4, wherein the processing liquid nozzle includes an arm portion extending horizontally and a nozzle portion extending downward from the arm portion and ejecting the processing liquid downward, and the mirror surface is provided on the nozzle portion.

6. The substrate processing apparatus according to claim 5, wherein the water-repellent surface is provided on the arm portion.

7. The substrate processing apparatus of claim 4, wherein the contact angle of water with said mirror surface is greater than 90 degrees.

8. A substrate processing apparatus according to any one of claims 1 to 3, further comprising: a spin motor that rotates the substrate held by the substrate holder about a vertical axis of rotation passing through a center of the substrate; a horizontal actuator that generates power to move the processing liquid nozzle horizontally between a processing position where the processing liquid nozzle overlaps with the substrate held by the substrate holder in a planar view and a standby position where the processing liquid nozzle does not overlap with the substrate held by the substrate holder in a planar view; and a control device that moves the processing liquid nozzle from the processing position to the standby position by the horizontal actuator while drying the substrate by rotating the substrate by the spin motor after the processing liquid nozzle located at the processing position supplies the processing liquid to the top surface of the substrate held by the substrate holder.

9. A substrate processing apparatus as described in any one of claims 1 to 3, further comprising: a horizontal actuator that generates power to horizontally move the processing liquid nozzle between a processing position where the processing liquid nozzle overlaps with the substrate held by the substrate holder in a planar view and a standby position where the processing liquid nozzle does not overlap with the substrate held by the substrate holder in a planar view; a cleaning nozzle that sprays a cleaning liquid toward the outer surface of the processing liquid nozzle located at the standby position; and a drying nozzle that sprays a drying gas toward the outer surface of the processing liquid nozzle located at the standby position.

10. A substrate processing method comprising: a step of ejecting a processing liquid downward from a processing liquid nozzle toward an upper surface of a substrate held horizontally by a substrate holder; and a step of bringing mist and droplets generated when the processing liquid nozzle ejects the processing liquid into contact with a water-repellent surface provided on the outer surface of the processing liquid nozzle.

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