Substrate processing method and substrate processing device

Abstract

To provide a substrate processing method capable of reducing the amount of IPA used when discharging an IPA liquid film from an upper surface of a substrate.SOLUTION: A substrate processing method includes: a hole forming step of forming an exposed hole HL exposing a central part of an upper surface of a substrate W, at a center of a liquid film by discharging gas from a gas nozzle 37 toward the central part of the upper surface of the substrate W while rotating the substrate W with an IPA nozzle 35 stopping the discharge of IPA; and a hole enlargement step of enlarging an outer edge HLe of the exposed hole HL to the outer periphery of the upper surface of the substrate W by horizontally moving the gas nozzle 37 from a gas center position to a gas edge position while rotating the substrate W, stopping spaying IPA by the IPA nozzle 35, and discharging gas toward the upper surface of the substrate W by the gas nozzle 37.SELECTED DRAWING: Figure 5D-F

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus for processing substrates, including, for example, semiconductor wafers, substrates for FPDs (Flat Panel Displays) such as liquid crystal displays and organic EL (electroluminescence) displays, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, and substrates for solar cells. [Background technology]

[0002] Patent Document 1 discloses that a drying liquid such as IPA (isopropyl alcohol) is supplied to a substrate, and then the substrate is dried. More specifically, Patent Document 1 discloses that the supply position of the drying liquid relative to the substrate is moved from the center to the peripheral edge of the substrate, and that the supply position of the drying gas relative to the substrate is moved from the center to the peripheral edge of the substrate in accordance with the movement of the supply position of the drying liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-4996 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the substrate processing described in Patent Document 1, drying liquid is supplied to the substrate even when the supply position of the drying gas to the substrate is moved from the center to the peripheral edge of the substrate, so a large amount of drying liquid is required.

[0005] At least one embodiment of the present invention provides a substrate processing method and a substrate processing apparatus that can reduce the amount of IPA used when discharging the IPA liquid film from the upper surface of a substrate. [Means for solving the problem]

[0006] One embodiment of the present invention includes a liquid film forming process in which IPA (isopropyl alcohol) is discharged from an IPA nozzle toward an upper surface of a substrate while the substrate is being rotated around a vertical rotation axis passing through a center of the substrate, the substrate being held horizontally, to thereby cover the entire upper surface of the substrate with a liquid film that is a film of the IPA; and a liquid film forming process in which, while the substrate is being rotated around the rotation axis with the IPA nozzle stopping from discharging the IPA, a gas is discharged from a gas nozzle toward the center of the upper surface of the substrate, thereby forming an exposure hole that exposes the center of the upper surface of the substrate at the center of the liquid film. and a hole enlarging step of enlarging an outer edge of the exposed hole to the outer periphery of the upper surface of the substrate by horizontally moving the gas nozzle from a gas center position where the gas discharged from the gas nozzle collides with the center part of the upper surface of the substrate to a gas edge position where the gas discharged from the gas nozzle collides with the outer periphery of the upper surface of the substrate while the substrate is rotating around the rotation axis, the IPA nozzle has stopped discharging the IPA, and the gas nozzle is discharging gas toward the upper surface of the substrate.

[0007] In the above embodiment, at least one of the following features may be added to the substrate processing method.

[0008] The substrate processing method further includes a photographing process for generating an image by a camera by photographing the top surface of the substrate while the gas nozzle is moving toward the gas edge position in the hole enlargement process, and an image determination process for determining, based on the image, whether at least one of concentric interference fringes and a concentric temperature distribution in which temperature alternately increases and decreases as the distance from the rotation axis increases is occurring on the top surface of the substrate.

[0009] The image assessment process includes a process of determining whether or not at least one of the interference fringes and the temperature distribution occurs on the top surface of the substrate based on the image, thereby determining whether or not liquid residue of the IPA occurs in the inner portion, which is closer to the rotation axis than the collision position where the gas ejected from the gas nozzle collides with the top surface of the substrate in the hole enlargement process.

[0010] The hole enlargement process is a process of horizontally moving the gas nozzle from the gas center position to the gas edge position at a nozzle movement speed, and the substrate processing method further includes a speed maintaining process of moving the gas nozzle to the gas edge position while having the camera photograph the top surface of the substrate without changing the nozzle movement speed if it is determined in the image determination process that at least one of the interference fringes and the temperature distribution is occurring, and a speed change process of changing the nozzle movement speed when performing the hole enlargement process on another substrate after it is determined in the image determination process that at least one of the interference fringes and the temperature distribution is occurring.

[0011] The image determination process includes a process of determining whether or not at least one of the interference fringes and the temperature distribution occurs on the top surface of the substrate based on the image, thereby determining whether or not a liquid decrease occurs in the thickness of the liquid film at the outer periphery of the top surface of the substrate before the gas nozzle reaches the gas edge position during the hole enlargement process.

[0012] The moving speed of the gas nozzle in the hole enlarging step is a speed at which the outer edge of the exposed hole reaches the outer periphery of the upper surface of the substrate before the outer periphery is exposed from the liquid film due to rotation of the substrate.

[0013] The moving speed of the gas nozzle in the hole enlarging step is set so that the boundary between the liquid film and the outer edge of the exposed hole is always within the atmosphere formed by the gas nozzle.

[0014] In an xy coordinate system in which the x-axis represents the rotation speed of the substrate and the y-axis represents the movement speed of the gas nozzle, the combination of the rotation speed of the substrate and the movement speed of the gas nozzle in the hole enlargement step falls within the region from the line represented by the following formula (1) to the line represented by formula (2) when the rotation speed of the substrate is in the range of 300 to 2500 rpm (revolutions per minute). y=0.1209x+39 (1) y=0.0991x-10.65 (2)

[0015] In the xy coordinate system, the combination of the rotation speed of the substrate and the moving speed of the gas nozzle in the hole enlargement step, when the rotation speed of the substrate is in the range of 300 to 2500 rpm, belongs to a region where the region from the line expressed by the formula (1) to the line expressed by the formula (2) overlaps with the region from the line expressed by the following formula (3) to the line expressed by the formula (4). y=0.1209x+17.1 (3) y=0.1209x-21.35 (4)

[0016] Another embodiment of the present invention is a method for manufacturing a substrate holder that holds a substrate horizontally; a spin motor that rotates the substrate held by the substrate holder about a vertical rotation axis that passes through a center of the substrate; an IPA nozzle that, while the spin motor is rotating the substrate, ejects IPA (isopropyl alcohol) toward an upper surface of the substrate held by the substrate holder, thereby covering the entire upper surface of the substrate with a liquid film that is a film of the IPA; and, while the spin motor is rotating the substrate and the IPA nozzle stops ejecting the IPA, ejects gas toward a center of the upper surface of the substrate held by the substrate holder, thereby covering the entire upper surface of the substrate. a gas nozzle configured to form an exposure hole in the center of the liquid film, exposing the center of the liquid film, and a nozzle actuator configured to expand an outer edge of the exposure hole to the outer periphery of the upper surface of the substrate by horizontally moving the gas nozzle from a gas center position where the gas discharged from the gas nozzle collides with the center of the upper surface of the substrate to a gas edge position where the gas discharged from the gas nozzle collides with the outer periphery of the upper surface of the substrate, while the spin motor is rotating the substrate, the IPA nozzle has stopped discharging the IPA, and the gas nozzle is discharging gas toward the upper surface of the substrate held by the substrate holder. At least one of the features described above regarding the substrate processing method may be added to the substrate processing apparatus. [Brief explanation of the drawings]

[0017] [Figure 1A] FIG. 1 is a schematic plan view showing a layout of a substrate processing apparatus according to a first embodiment. [Figure 1B] FIG. 2 is a schematic side view of the substrate processing apparatus. [Figure 2] 1 is a schematic diagram showing the interior of a processing unit provided in a substrate processing apparatus as viewed horizontally. [Figure 3] FIG. 2 is a block diagram showing an electrical configuration of the substrate processing apparatus. [Figure 4] 5A to 5C are process diagrams for explaining an example of substrate processing performed by the substrate processing apparatus. [Figure 5A-C] 5A and 5B are schematic diagrams showing a cross section and a plan view of a substrate when the example of the process shown in FIG. 4 is being performed. [Figure 5D-F] 5A and 5B are schematic diagrams showing a cross section and a plan view of a substrate when the example of the process shown in FIG. 4 is being performed. [Figure 6] 10 is a graph showing the relationship between the rotation speed of the substrate and the moving speed of the gas nozzle. [Figure 7] FIG. 10 is a schematic cross-sectional view of a substrate when IPA remains inside the ring-shaped liquid film. [Figure 8] 10 is a schematic cross-sectional view of a substrate when the outer periphery of the upper surface of the substrate is exposed before the inner periphery of the ring-shaped liquid film reaches the outer periphery of the upper surface of the substrate. FIG. [Figure 9] FIG. 10 is a conceptual diagram for explaining the change over time in the thickness of an IPA liquid film on the upper surface of a substrate. [Figure 10] FIG. 10 is a conceptual diagram showing the relationship between the moving speed of the gas nozzle and the distribution of IPA on the substrate. [Figure 11] FIG. 1 is a schematic diagram showing a horizontal view of a spin chuck, a gas nozzle, and a camera. [Figure 12] FIG. 1 is a schematic top view of a spin chuck, a gas nozzle, and a camera. [Figure 13] 10 is a flowchart illustrating another example of substrate processing performed by the substrate processing apparatus. [Figure 14] 10 is a schematic diagram of an IPA nozzle and a gas nozzle according to another embodiment, viewed horizontally. FIG. [Figure 15] FIG. 10 is a schematic diagram showing an IPA nozzle and a gas nozzle according to yet another embodiment, viewed horizontally. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] FIG. 1A is a schematic plan view showing the layout of a substrate processing apparatus 1 according to a first embodiment. FIG. 1B is a schematic side view of the substrate processing apparatus 1. 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 a carrier CA that accommodates a substrate W, a plurality of processing units 2 that treat the substrate W transferred from the carrier CA on the load port LP with processing fluids such as processing liquids and processing gases, 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 an enclosed space accommodating the plurality of processing units 2 and the transfer system TS, and a controller 3 that controls the substrate processing apparatus 1.

[0020] 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 on top of 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 (left and right directions on the paper surface of FIG. 1A) in a plan view. In a plan view, the two rows face each other via a transport path TP.

[0021] 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.

[0022] The indexer robot IR includes one or more hands Hi that support a substrate W horizontally. 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 to 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.

[0023] The center robot CR includes one or more hands Hc that support the substrate W horizontally. 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 the substrate W to and from the indexer robot IR, and can transport the substrate W into and out of any of the processing units 2.

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

[0025] 2 is a horizontal schematic diagram of the interior of a processing unit 2 provided in the substrate processing apparatus 1. The processing unit 2 includes a box-shaped chamber 4 having an internal space, a spin chuck 10 that holds one substrate W horizontally in the chamber 4 and rotates the substrate W about a vertical rotation axis A1 that passes through the center of the substrate W, and a cylindrical processing cup 21 that surrounds the spin chuck 10 about the rotation axis A1.

[0026] The chamber 4 includes a box-shaped partition 5 having 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 air discharged into the exhaust duct 8 is changed according to the opening of an exhaust valve 9 disposed within the exhaust duct 8.

[0027] 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.

[0028] 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 the 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 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.

[0029] The processing cup 21 includes a plurality of guards 24 that receive the processing liquid discharged outward from the substrate W held on 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. Figure 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.

[0030] 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 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 that surrounds 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.

[0031] The processing unit 2 includes a guard lifting actuator 27 that individually raises and lowers the multiple guards 24. The guard lifting actuator 27 positions the guards 24 at any position within a range from the upper position to the lower position. FIG. 2 shows two guards 24 in the lower position. The upper position is a position where the upper end 24u of the guard 24 is located above the holding position where the substrate W held by the spin chuck 10 is located. The lower position is a position where the upper end 24u of the guard 24 is located below the holding position.

[0032] An actuator is a device that converts driving energy, such as electrical, fluid, magnetic, thermal, or chemical energy, into mechanical work, i.e., the movement of a tangible object. Actuators include electric motors (rotary motors), linear motors, air cylinders, and other devices. When the movement of the actuator differs from the movement of the object, a motion converter may be provided to convert the movement of the actuator into linear motion or rotation. For example, if the actuator is an electric motor that moves the object linearly, the rotation of the electric motor may be converted into linear motion by a motion converter such as a ball screw and ball nut.

[0033] The processing unit 2 includes a chemical nozzle 31 that discharges a chemical solution toward the upper surface of the substrate W held on the spin chuck 10, and a rinse solution nozzle 33 that discharges a rinse solution toward the upper surface of the substrate W held on the spin chuck 10. The processing unit 2 further includes an IPA nozzle 35 that discharges IPA toward the upper surface of the substrate W held on the spin chuck 10, and a gas nozzle 37 that discharges a gas toward the upper surface of the substrate W held on the spin chuck 10. Figure 2 shows an example in which the chemical solution is HF (hydrofluoric acid), the rinse solution is DIW (pure water), and the gas is nitrogen gas.

[0034] Chemical nozzle 31 is connected to chemical pipe 32p that guides the chemical. When chemical valve 32v attached to chemical pipe 32p is opened, the discharge port of chemical nozzle 31 continuously discharges the chemical downward. 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, organic acid (e.g., citric acid, oxalic acid, etc.), organic alkali (e.g., TMAH: tetramethylammonium hydroxide, etc.), surfactant, and corrosion inhibitor, or may be other liquids.

[0035] Although not shown, the chemical liquid valve 32v 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 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 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 or close the chemical liquid valve 32v, etc.

[0036] The rinse liquid nozzle 33 is connected to a rinse liquid pipe 34p that guides the rinse liquid. When a rinse liquid valve 34v attached to the rinse liquid pipe 34p is opened, the outlet of the rinse liquid nozzle 33 continuously discharges the rinse liquid downward. The rinse liquid may be any of pure water (deionized water: DIW), 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.

[0037] The IPA nozzle 35 is connected to an IPA pipe 36p to which an IPA valve 36v and a flow rate adjustment valve 36f are attached. When the IPA valve 36v is opened, IPA is supplied from the IPA pipe 36p to the IPA nozzle 35 at a flow rate corresponding to the aperture of the flow rate adjustment valve 36f, and is continuously ejected downward from the outlet of the IPA nozzle 35. Figure 2 shows an example in which the IPA nozzle 35 ejects IPA perpendicular to the top surface of the substrate W. When the control device 3 changes the aperture of the flow rate adjustment valve 36f, the flow rate of IPA ejected from the IPA nozzle 35 increases or decreases.

[0038] The IPA discharged from the IPA nozzle 35 is liquid IPA. IPA is an example of an organic solvent that is more volatile than water and has a lower surface tension than water. The temperature of the IPA discharged from the IPA nozzle 35 may be room temperature (for example, 20 to 30°C), or may be a value above room temperature but below the boiling point of IPA. In the latter case, a heater 36h may be provided to heat the IPA supplied to the IPA nozzle 35.

[0039] The gas nozzle 37 is connected to a gas pipe 38p to which a gas valve 38v and a flow rate control valve 38f are attached. When the gas valve 38v is opened, gas is supplied from the gas pipe 38p to the gas nozzle 37 at a flow rate corresponding to the opening of the flow rate control valve 38f, and is continuously discharged downward from the outlet of the gas nozzle 37. FIG. 2 shows an example in which the gas nozzle 37 discharges gas perpendicular to the upper surface of the substrate W. The gas discharged from the gas nozzle 37 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. The temperature of the gas discharged from the gas nozzle 37 may be room temperature or may be a value higher than room temperature.

[0040] The chemical liquid nozzle 31 may be a scan nozzle that moves the collision position of the chemical liquid 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 liquid on the substrate W. The same applies to the other nozzles. Figure 2 shows an example in which the chemical liquid nozzle 31, the rinse liquid nozzle 33, the IPA nozzle 35, and the gas nozzle 37 are scan nozzles.

[0041] Chemical liquid nozzle 31 is connected to nozzle actuator 32a, which moves chemical liquid nozzle 31 in at least one of the vertical and horizontal directions. Rinse liquid nozzle 33 is connected to nozzle actuator 34a, which moves rinse liquid nozzle 33 in at least one of the vertical and horizontal directions. Nozzle actuator 32a moves chemical liquid nozzle 31 horizontally between a processing position where the chemical liquid discharged from chemical liquid nozzle 31 is supplied to the upper surface of substrate W and a standby position where chemical liquid nozzle 31 is positioned around processing cup 21 in a plan view. The same applies to nozzle actuator 34a.

[0042] The IPA nozzle 35 and the gas nozzle 37 are connected to a nozzle actuator 38a that moves the IPA nozzle 35 and the gas nozzle 37 in at least one of the vertical and horizontal directions. The nozzle actuator 38a is connected to the IPA nozzle 35 and the gas nozzle 37 via a nozzle arm 38. The IPA nozzle 35 and the gas nozzle 37 extend downward from the nozzle arm 38.

[0043] The nozzle actuator 38a may rotate the nozzle arm 38 about a vertical axis positioned around the processing cup 21 in a plan view, or may translate the nozzle arm 38 horizontally. In the former case, the IPA nozzle 35 and the gas nozzle 37 move horizontally along a path that is arc-shaped in a plan view (see FIG. 5A). The radius of curvature of the path through which the IPA nozzle 35 passes may be equal to or different from the radius of curvature of the path through which the gas nozzle 37 passes. FIG. 5A shows an example of the former case.

[0044] The nozzle actuator 38a moves the IPA nozzle 35 and the gas nozzle 37 while maintaining constant relative positions of the IPA nozzle 35 and the gas nozzle 37. The nozzle actuator 38a moves the IPA nozzle 35 and the gas nozzle 37 horizontally between a processing position where a fluid ejected from at least one of the IPA nozzle 35 and the gas nozzle 37 is supplied to the upper surface of the substrate W and a standby position where the IPA nozzle 35 and the gas nozzle 37 are positioned around the processing cup 21 in a plan view.

[0045] The processing positions include an IPA center position, a gas center position, and a gas edge position. The IPA center position is a position where IPA discharged from the IPA nozzle 35 collides with the center of the upper surface of the substrate W. The gas center position is a position where gas discharged from the gas nozzle 37 collides with the center of the upper surface of the substrate W. The gas edge position is a position where gas discharged from the gas nozzle 37 collides with the outer periphery of the upper surface of the substrate W. While the IPA nozzle 35 and the gas nozzle 37 move from the gas center position to the gas edge position, the positions of the IPA nozzle 35 and the gas nozzle 37 in the vertical direction do not change.

[0046] Next, the electrical configuration of the substrate processing apparatus 1 will be described.

[0047] 3 is a block diagram showing the electrical configuration of the substrate processing apparatus 1. The substrate processing apparatus 1 includes a control device 3 that 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 computer main body 3a and a peripheral device 3d connected to the computer main body 3a.

[0048] The computer main body 3a includes a CPU 3b (central processing unit) that executes various commands, and a memory 3c that stores information to be transmitted and received between the CPU 3b. 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 HC. 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.

[0049] The control device 3 is connected to an input device 3h and a display device 3i. The input device 3h 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 3i. The input device 3h may be any of a keyboard, a pointing device, and a touch panel, or may be a device other than these. The substrate processing apparatus 1 may be provided with a touch panel display that serves as both the input device 3h and the display device 3i.

[0050] 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, or may be one that has been sent from a removable medium RM to the storage 3e via a reader 3f, or may be one that has been sent from an external device such as a host computer HC via a communication device 3g to the storage 3e.

[0051] 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.

[0052] The storage 3e stores a plurality of recipes RC. The recipes RC are information that specifies the processing content, processing conditions, and processing procedures for the substrates W. The plurality of recipes RC differ from one another in at least one of the processing content, processing conditions, and processing procedures for the substrates W. The control device 3 controls the substrate processing apparatus 1 so that the substrates W are processed in accordance with the recipes RC specified by the host computer HC. The control device 3 is programmed to execute each of the processes described below.

[0053] Next, an example of processing of the substrate W performed by the substrate processing apparatus 1 will be described.

[0054] FIG. 4 is a process diagram illustrating an example of processing of a substrate W performed by the substrate processing apparatus 1. FIGS. 5A, 5B, 5C, 5D, 5E, and 5F are schematic diagrams showing a cross section and a plan view of the substrate W when the example of processing shown in FIG. 4 is being performed. In FIGS. 5A to 5E, the cross-hatched area represents IPA (liquid). In FIGS. 5C to 5F, the three straight lines extending downward from the gas nozzle 37 represent the gas discharged from the gas nozzle 37. In the following, reference will be made to FIGS. 2 and 4. FIGS. 5A to 5F will be referred to as appropriate.

[0055] 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 on which a pattern is formed, or a substrate W on which no pattern is formed. In the latter case, the pattern may be formed in a chemical solution supplying process described below.

[0056] When the substrate W is processed by the substrate processing apparatus 1, a loading step (step S1 in FIG. 4) of loading the substrate W into the chamber 4 is performed.

[0057] Specifically, with all guards 24 in the lower position and all scan nozzles in the standby position, the center robot CR (see FIG. 1A) supports the substrate W with the hand Hc and causes the hand Hc to enter the chamber 4. The center robot CR places the substrate W on the hand Hc on the multiple chuck pins 11 with the surface of the substrate W facing upward. The multiple chuck pins 11 are then pressed against the edge surface of the substrate W to hold it in place. After placing the substrate W on the spin chuck 10, the center robot CR retracts the hand Hc from the interior of the chamber 4.

[0058] After the substrate W is held by the spin chuck 10, a chemical liquid supplying step (step S2 in FIG. 4) is performed in which a chemical liquid is supplied to the upper surface of the substrate W to form a liquid film of the chemical liquid covering the entire upper surface of the substrate W.

[0059] Specifically, the nozzle actuator 32a moves the chemical 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 rotating the substrate W. This causes the substrate W to rotate at the chemical supply speed. The guard 24 may start rising simultaneously with the chemical nozzle 31 reaching the processing position, or may start before or after it reaches the processing position. The same applies to the timing at which the rotation of the substrate W starts.

[0060] With the chemical liquid nozzle 31 in the processing position, at least one guard 24 in the upper position, and the substrate W rotating at the chemical liquid supply speed, the chemical liquid valve 32v is opened and the chemical liquid nozzle 31 starts to discharge 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. As a result, the chemical liquid is supplied to the entire upper surface of the substrate W, and a liquid film of the chemical liquid is formed that covers the entire upper surface of the substrate W.

[0061] 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. Thereafter, the nozzle actuator 32a moves the chemical liquid nozzle 31 to the standby position. While the chemical liquid nozzle 31 is discharging the chemical liquid, the nozzle actuator 32a may move the collision position of the chemical liquid against the upper surface of the substrate W so that the collision position passes through the center and the outer periphery, or may keep the collision position stationary at the center. Whether or not the collision position is moved applies similarly to the processing liquid supplied to the upper surface of the substrate W after the chemical liquid.

[0062] After the chemical liquid is supplied to the substrate W, a rinse liquid supply step (step S3 in FIG. 4) is performed in which pure water, which is an example of a rinse liquid, is supplied to the upper surface of the substrate W to rinse away the chemical liquid on the substrate W with the pure water.

[0063] Specifically, with at least one guard 24 in 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 to discharge the rinse liquid. Before the discharge of pure water starts, the guard lifting actuator 27 may move at least one guard 24 vertically to switch the guard 24 that receives the liquid discharged from the substrate W.

[0064] The pure water discharged from the rinse liquid nozzle 33 collides with the upper surface of the substrate W, which is rotating at the rinse liquid supply speed, and then flows outward along the upper surface of the substrate W. The rinse liquid supply speed may be equal to or different from the chemical liquid supply speed. The chemical liquid on the substrate W is replaced with the pure water discharged from the rinse liquid nozzle 33. This forms a liquid film of pure water that covers the entire upper surface of the substrate W. 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.

[0065] After supplying the pure water to the substrate W, an organic solvent supply process (step S4 in Figure 4) is performed in which IPA, 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.

[0066] Specifically, with at least one guard 24 in the upper position, the nozzle actuator 38a moves the IPA nozzle 35 from the standby position to the IPA center position. Then, the IPA valve 36v is opened, and the IPA nozzle 35 starts discharging IPA. Before the discharging of IPA starts, the guard lifting / lowering actuator 27 may move at least one guard 24 vertically to switch the guard 24 that receives the liquid discharged from the substrate W.

[0067] The IPA discharged from the IPA nozzle 35 collides with the upper surface of the substrate W, which is rotating at the solvent supply speed, and then flows outward along the upper surface of the substrate W. The solvent supply speed may be equal to or different from the rinse liquid supply speed. The pure water on the substrate W is replaced with the IPA discharged from the IPA nozzle 35. This forms a liquid film of IPA that covers the entire upper surface of the substrate W (see FIG. 5A). When a predetermined time has elapsed since the IPA valve 36v was opened, the IPA valve 36v is closed, and the discharge of IPA is stopped (see FIG. 5B).

[0068] After the liquid film of pure water is replaced with the liquid film of IPA, a drying process is performed to dry the substrate W by discharging the liquid film of IPA from the upper surface of the substrate W. The drying process includes a hole forming process (step S5 in FIG. 4) of forming an exposure hole HL (see FIG. 5D) in the center of the liquid film of IPA to expose the center of the upper surface of the substrate W from the liquid film of IPA, and a hole enlarging process (step S6 in FIG. 4) of enlarging the outer edge HLe (see FIG. 5D) of the exposure hole HL to the outer periphery of the upper surface of the substrate W.

[0069] In the organic solvent supplying step described above, the IPA nozzle 35 and the gas nozzle 37 are disposed at an IPA center position (position shown in FIG. 5A) where the IPA nozzle 35 discharges IPA toward the center of the upper surface of the substrate W. Simultaneously with, before, or after the IPA nozzle 35 stops discharging IPA, the nozzle actuator 38a moves the IPA nozzle 35 and the gas nozzle 37 to a gas center position (position shown in FIG. 5C) where the gas nozzle 37 discharges gas toward the center of the upper surface of the substrate W.

[0070] At the same time as or after the gas nozzle 37 reaches the gas center position, the gas valve 38v is opened, and the gas nozzle 37 starts to discharge the inert gas. Therefore, the gas nozzle 37 discharges the inert gas toward the center of the upper surface of the substrate W, while the IPA nozzle 35 stops discharging IPA, the substrate W is rotating, the entire upper surface of the substrate W is covered with a liquid film of IPA, and at least one guard 24 is in the upper position. The IPA nozzle 35 may continue to discharge IPA until the gas nozzle 37 starts to discharge the inert gas at the gas center position.

[0071] The inert gas discharged from the gas nozzle 37 collides with the IPA liquid film at the center of the upper surface of the substrate W, and then flows outward in all directions along the surface of the IPA liquid film. This reduces the thickness of the IPA liquid film at the center, and a substantially circular exposure hole HL is formed in the center of the IPA liquid film (see FIG. 5D). Once the exposure hole HL is formed, the inert gas discharged from the gas nozzle 37 is sprayed onto the center of the upper surface of the substrate W. Even if a trace amount of IPA that is too small to be seen with the naked eye remains at the center of the upper surface of the substrate W, this IPA is evaporated by the supply of inert gas. This dries the center of the upper surface of the substrate W.

[0072] Furthermore, the inert gas flowing outward along the upper surface of the substrate W tends to move the IPA on the substrate W outward. The centrifugal force generated by the rotation of the substrate W also tends to move the IPA on the substrate W outward. While the gas nozzle 37 is discharging the inert gas at the gas center position, the outer edge HLe (see FIG. 5E) of the exposure hole HL, which corresponds to the inner periphery of the ring-shaped liquid film, gradually becomes larger while remaining circular or nearly circular and concentric with the substrate W. As a result, the diameter of the exposure hole HL, which corresponds to the inner diameter of the ring-shaped liquid film, gradually increases.

[0073] When forming the exposure holes HL, the IPA nozzle 35 and the gas nozzle 37 are positioned at the gas center position (the position shown in FIGS. 5C and 5D). Simultaneously with or after the exposure holes HL are formed, the nozzle actuator 38a horizontally moves the IPA nozzle 35 and the gas nozzle 37 toward the gas edge position (the position shown in FIG. 5F) where the gas nozzle 37 discharges gas toward the outer periphery of the upper surface of the substrate W. Therefore, with the IPA nozzle 35 stopping the discharge of IPA, the substrate W rotating, and at least one guard 24 positioned in the upper position, the gas nozzle 37 moves horizontally from the gas center position toward the gas edge position while discharging inert gas toward the upper surface of the substrate W.

[0074] The combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37 when the IPA nozzle 35 and the gas nozzle 37 are being moved toward the gas edge position will be described later. The spin motor 14 may maintain the rotation speed of the substrate W constant or may change it while the IPA nozzle 35 and the gas nozzle 37 are moving from the gas center position to the gas edge position. The nozzle actuator 38a may maintain the movement speed of the IPA nozzle 35 and the gas nozzle 37 constant or may change it during this period.

[0075] When the IPA nozzle 35 and the gas nozzle 37 move horizontally from the gas center position toward the gas edge position, the horizontal distance from the rotation axis A1 of the substrate W to the gas nozzle 37 (hereinafter also referred to as the "distance to the gas nozzle 37") increases. The outer edge HLe of the exposure hole HL, which corresponds to the inner periphery of the ring-shaped liquid film, increases by the amount of the increase in the distance to the gas nozzle 37. The outer edge HLe of the exposure hole HL may reach the outer periphery of the top surface of the substrate W at the same time that the gas nozzle 37 reaches the gas edge position, or may reach the outer periphery before the gas nozzle 37 reaches the gas edge position.

[0076] When the exposure hole HL is widened while the gas nozzle 37 is moved toward the gas edge position, the gas nozzle 37 may continue to discharge the inert gas toward the inner periphery of the ring-shaped liquid film, or may continue to discharge the inert gas toward a position within the upper surface of the substrate W that is surrounded by the ring-shaped liquid film in a plan view. In the former case, the interface between the inner periphery of the ring-shaped liquid film and the upper surface of the substrate W is always placed under a high-pressure atmosphere formed by the gas nozzle 37. Therefore, the outer periphery of the exposed portion of the upper surface of the substrate W can be instantly dried.

[0077] When the exposure hole HL is formed, the IPA liquid film changes from a circle with a diameter equal to the diameter of the substrate W to a ring shape concentric with the substrate W. Thereafter, the outer periphery of the upper surface of the substrate W remains covered with the ring-shaped liquid film, that is, the inner diameter of the ring-shaped liquid film gradually increases while the outer diameter of the ring-shaped liquid film remains equal to the diameter of the substrate W. Accordingly, the IPA flows down from the outer periphery of the upper surface of the substrate W. The area of the exposed portion of the upper surface of the substrate W that is not covered with the IPA liquid film increases as the inner diameter of the ring-shaped liquid film increases. When the outer edge HLe of the exposure hole HL extends to the outer periphery of the upper surface of the substrate W, the liquid film disappears from the upper surface of the substrate W, and the entire upper surface of the substrate W is exposed.

[0078] When the gas nozzle 37 is moved from the gas center position toward the gas edge position while the substrate W is being rotated, the inner diameter of the ring-shaped liquid film increases, and the outer diameter of the exposed portion of the upper surface of the substrate W also increases. At this time, even if a trace amount of IPA that is not visible to the naked eye remains in the portion where the liquid film has disappeared, that is, on the periphery of the exposed portion of the upper surface of the substrate W, this IPA evaporates due to the supply of inert gas. Therefore, the periphery of the exposed portion of the upper surface of the substrate W quickly dries.

[0079] In this way, the exposed portion of the upper surface of the substrate W is quickly dried. When the gas nozzle 37 reaches the gas edge position, the inert gas discharged from the gas nozzle 37 collides with the entire upper surface of the substrate W. This dries the entire upper surface of the substrate W. When the gas nozzle 37 reaches the gas edge position, the gas valve 38v is closed, and the gas nozzle 37 stops discharging the inert gas. Thereafter, the nozzle actuator 38a moves the IPA nozzle 35 and the gas nozzle 37 from the gas edge position to the standby position.

[0080] After the substrate W is dried, an unloading step (step S7 in FIG. 4) is performed in which the substrate W is unloaded from the chamber 4.

[0081] Specifically, the guard lifting actuator 27 lowers all of the guards 24 to the lower position. Thereafter, the center robot CR causes the hand Hc to enter the chamber 4. After the plurality of chuck pins 11 release the substrate W, the center robot CR supports the substrate W on the spin chuck 10 with the hand Hc. Thereafter, the center robot CR retracts the hand Hc from the inside of the chamber 4 while still supporting the substrate W with the hand Hc. As a result, the processed substrate W is removed from the chamber 4.

[0082] Next, the rotation speed of the substrate W and the movement speed of the gas nozzle 37 will be described.

[0083] 6 is a graph created based on the results of a discharge test performed multiple times in which an IPA liquid film was discharged from the top surface of the substrate W as shown in FIGS. 5A to 5F at a substrate W rotation speed ranging from 300 to 2500 rpm (revolutions per minute). FIG. 6 shows a Cartesian coordinate system in which the horizontal axis (x-axis) represents the rotation speed of the substrate W and the vertical axis (y-axis) represents the movement speed of the gas nozzle 37. In the following description, the speed condition refers to a combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37.

[0084] The discharge tests were carried out in an environment where the temperature was room temperature and the pressure was at or near 1 atmosphere. The conditions were the same for all discharge tests except for at least one of the rotation speed of the substrate W and the movement speed of the gas nozzle 37. The temperature and flow rate of IPA discharged from the IPA nozzle 35 when forming the liquid film to be discharged in the discharge tests were 70°C and 300 ml / min. The diameter of the substrate W used in the discharge tests was 300 mm.

[0085] 6, the cross-hatched area represents the middle region, the hatched area extending to the upper right represents the upper region, and the hatched area extending to the upper left represents the lower region. The upper region is the region above the middle region, and the lower region is the region below the middle region.

[0086] The intermediate region is a region defined by the speed conditions of multiple discharge tests in which the outer periphery of the top surface of the substrate W remains covered with a liquid film until the inner periphery of the ring-shaped liquid film reaches the outer periphery of the top surface of the substrate W, and no visually visible IPA (liquid) remains inside the ring-shaped liquid film.

[0087] The upper region is a region defined by the speed conditions of multiple draining tests in which the outer periphery of the upper surface of the substrate W remains covered with a liquid film until the inner periphery of the ring-shaped liquid film reaches the outer periphery of the upper surface of the substrate W, but visually visible IPA (liquid) remains inside the ring-shaped liquid film. Figure 7 shows the liquid film when the liquid film is drained under speed conditions that belong to the upper region. The cross-hatched region in Figure 7 represents IPA (liquid). If we consider that the IPA remaining inside, which is thinner than the ring-shaped liquid film, also constitutes a ring-shaped liquid film, under speed conditions that belong to the upper region, the interface between the inner periphery of the ring-shaped liquid film and the upper surface of the substrate W is outside the high-pressure atmosphere created by the gas nozzle 37.

[0088] The lower region is a region defined by the speed conditions of multiple discharge tests in which no visible IPA (liquid) remained inside the ring-shaped liquid film, but the outer periphery of the top surface of the substrate W was exposed before the inner periphery of the ring-shaped liquid film reached the outer periphery of the top surface of the substrate W. Figure 8 shows the liquid film when it is being discharged under speed conditions that belong to the lower region. The cross-hatched region in Figure 8 represents IPA (liquid). Under speed conditions that belong to the lower region, the outer periphery of the top surface of the substrate W is exposed due to the rotation of the substrate W.

[0089] The intermediate region includes the approximation line L5. The approximation line L5 is the regression line with the smallest sum of errors with respect to each speed condition included in the intermediate region when calculated using the least squares method. The third boundary line L3 is the line with the largest y-intercept among the lines that have the same slope as the approximation line L5 and pass through any of the speed conditions of the discharge test that belong to the intermediate region. The fourth boundary line L4 is the line with the smallest y-intercept among the lines that have the same slope as the approximation line L5 and pass through any of the speed conditions of the discharge test that belong to the intermediate region. The region between the third boundary line L3 and the fourth boundary line L4 is the central region. Part of the central region is included in the lower region. The remaining part of the central region is included in the intermediate region.

[0090] The intermediate region is the region between the upper region and the lower region. The first boundary line L1 and the second boundary line L2 are lines included in the intermediate region. Figure 6 shows an example in which the portion of the contour of the intermediate region that contacts the upper region is the first boundary line L1, and the portion of the contour line that contacts the lower region is the second boundary line L2. In this example, the region between the first boundary line L1 and the second boundary line L2 is the intermediate region.

[0091] The first boundary line L1 may be a straight line defined by the speed condition that is closest to the approximation line L5 for each of multiple values of the rotation speed of the substrate W among the speed conditions of the multiple discharge tests belonging to the lower region, or it may be another line. The same applies to the second boundary line L2. In the former case, at least one of the first boundary line L1 and the second boundary line L2 may be a straight line whose slope is the same as or approximately the same as that of the approximation line L5.

[0092] The first boundary line L1 is expressed by formula (1), the second boundary line L2 by formula (2), the third boundary line L3 by formula (3), the fourth boundary line L4 by formula (4), and the approximation line L5 by formula (5). In formulas (1) to (5), x represents the rotation speed of the substrate W, and y represents the movement speed of the gas nozzle 37. y=0.1209x+39 (1) y=0.0991x-10.65 (2) y=0.1209x+17.1 (3) y=0.1209x-21.35 (4) y=0.1209x+3.4197 (5)

[0093] In the hole enlargement step (step S6 in FIG. 4), the combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37 when the IPA nozzle 35 and the gas nozzle 37 are being moved toward the gas edge position may be set to belong to the intermediate region, or may be set to not belong to the intermediate region. In the former case, the combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37 that belongs to the intermediate region may be specified in the recipe RC (see FIG. 3).

[0094] When a combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37 that belongs to the intermediate region is specified in the recipe RC, when the control device 3 controls the substrate processing apparatus 1 in accordance with the recipe RC, the substrate W rotates and the gas nozzle 37 moves under speed conditions that belong to the intermediate region when discharging the IPA liquid film from the upper surface of the substrate W. This allows the exposed portion of the upper surface of the substrate W to spread from the center of the upper surface of the substrate W to the outer periphery of the upper surface of the substrate W, while keeping the outer periphery of the upper surface of the substrate W covered with the liquid film until the inner periphery of the ring-shaped liquid film reaches the outer periphery of the upper surface of the substrate W.

[0095] Next, the effects of this embodiment will be described.

[0096] In this embodiment, IPA is discharged from the IPA nozzle 35 toward the upper surface of the substrate W while the substrate W is being rotated. This forms a liquid film of IPA that covers the entire upper surface of the substrate W. Thereafter, the IPA nozzle 35 is caused to stop discharging IPA, and the gas nozzle 37 is caused to discharge gas. While the substrate W is rotating, the gas nozzle 37 discharges gas toward the exposure hole HL formed in the center of the liquid film. The gas discharged from the gas nozzle 37 collides with the upper surface of the substrate W within the exposure hole HL.

[0097] After the gas nozzle 37 starts discharging gas, the substrate W is rotated, the IPA nozzle 35 stops discharging IPA, and the gas nozzle 37 is moved horizontally while discharging gas toward the upper surface of the substrate W. The position at which the gas discharged from the gas nozzle 37 collides with the substrate W moves from the center of the upper surface of the substrate W to the outer periphery of the upper surface of the substrate W as the gas nozzle 37 moves. As the gas nozzle 37 moves, the outer edge HLe of the exposure hole HL expands to the outer periphery of the upper surface of the substrate W, and all of the liquid film is discharged from the substrate W. Therefore, the amount of IPA used can be reduced compared to when the liquid film is removed from the substrate W while the IPA nozzle 35 is discharging IPA.

[0098] If the gas nozzle 37, which is discharging gas, is moved horizontally toward the outer periphery of the substrate W while the IPA nozzle 35 stops discharging IPA, the IPA may disappear from the outer periphery of the upper surface of the substrate W before the outer edge HLe of the exposure hole HL reaches the outer periphery of the upper surface of the substrate W, and the outer periphery of the upper surface of the substrate W may become exposed from the liquid film. In this case, the outer diameter of the ring-shaped liquid film decreases from a value approximately equal to the diameter of the substrate W to a value smaller than that diameter. During this process, the pattern may collapse on the outer periphery of the upper surface of the substrate W or in the area inside it. If the gas nozzle 37 is moved quickly to prevent such collapse, IPA may remain inside the ring-shaped liquid film.

[0099] In an xy coordinate system in which the x-axis represents the rotation speed of the substrate W and the y-axis represents the movement speed of the gas nozzle 37, the combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37 in the hole enlargement process falls within the region from the first boundary line L1 represented by equation (1) to the second boundary line L2 represented by equation (2) when the rotation speed of the substrate W is in the range of 300 to 2500 rpm (this region includes the lines represented by equations (1) and (2)).

[0100] In this case, it is possible to prevent the outer diameter of the ring-shaped liquid film from decreasing from a value substantially equal to the diameter of the substrate W to a value smaller than that diameter before the outer edge HLe of the exposure hole HL reaches the outer periphery of the upper surface of the substrate W. In addition, it is possible to prevent IPA from remaining in the region on the upper surface of the substrate W to which the gas discharged from the gas nozzle 37 is supplied. This reduces pattern collapse that occurs on or near the outer periphery of the upper surface of the substrate W, and prevents IPA from remaining inside the ring-shaped liquid film.

[0101] In the xy coordinate system, the combination of the rotation speed of the substrate W and the movement speed of the gas nozzle 37 in the hole enlargement process, when the rotation speed of the substrate W is in the range of 300 to 2500 rpm, belongs to a region where the region from the first boundary line L1 represented by equation (1) to the second boundary line L2 represented by equation (2) overlaps with the region from the third boundary line L3 represented by equation (3) to the fourth boundary line L4 represented by equation (4) (this region includes the lines represented by equations (3) and (4)).

[0102] The overlapping region between the first boundary line L1 expressed by formula (1) and the second boundary line L2 expressed by formula (2) and the region between the third boundary line L3 expressed by formula (3) and the fourth boundary line L4 expressed by formula (4) is narrower than the region between the first boundary line L1 expressed by formula (1) and the second boundary line L2 expressed by formula (2). In this case, the possibility that the outer diameter of the ring-shaped liquid film will decrease from a value approximately equal to the diameter of the substrate W to a value smaller than that diameter before the outer edge HLe of the exposure hole HL reaches the outer periphery of the top surface of the substrate W can be further reduced. In addition, the possibility that IPA will remain in the region on the top surface of the substrate W to which the gas discharged from the gas nozzle 37 is supplied can be further reduced.

[0103] Next, a second embodiment will be described.

[0104] 9 to 13 below, the same components as those shown in the above-described FIGS. 1A to 8 are denoted by the same reference numerals as in FIG. 1A etc., and the description thereof will be omitted.

[0105] The main difference between the second embodiment and the first embodiment is that the hole enlarging step (step S6 in FIG. 4) according to the first embodiment is performed while the top surface of the substrate W is photographed by a camera 43 (see FIG. 11).

[0106] When the IPA on the upper surface of the substrate W decreases while the substrate W is rotating about the rotation axis A1 (see FIG. 10), the thickness of the IPA liquid film may decrease unevenly rather than uniformly. In this case, the thickness of the IPA liquid film on the upper surface of the substrate W may alternately increase and decrease as the distance from the rotation axis A1 increases. In other words, areas where the IPA liquid film is relatively thick and areas where the IPA liquid film is relatively thin may alternate concentrically.

[0107] FIG. 9 is a conceptual diagram for explaining the change over time in the thickness of the IPA liquid film on the upper surface of the substrate W. The left-right direction of the paper in FIG. 9 corresponds to the radial direction of the substrate W (the direction perpendicular to the rotation axis A1). Lines LA, LB, and LC in FIG. 9 indicate the surface of the IPA liquid film. Line LA in FIG. 9 indicates the surface of the liquid film before its thickness decreases. Lines LB and LC in FIG. 9 indicate the surface of the liquid film when its thickness is decreasing. The elapsed time after the IPA on the upper surface of the substrate W starts to decrease increases in the order of line LB and line LC.

[0108] When the thickness of the IPA liquid film on the upper surface of the substrate W decreases while the substrate W is rotating around the rotation axis A1, the thickness of the IPA liquid film may continuously increase and decrease alternately as the distance from the rotation axis A1 increases. Lines LB and LC in Figure 9 show an example in which the thickness of the IPA liquid film changes periodically as the distance from the rotation axis A1 increases.

[0109] When the IPA on the upper surface of the substrate W decreases while the substrate W is rotating about the rotation axis A1, the IPA liquid film may include multiple peaks 41 where the liquid film is relatively thick and multiple valleys 42 where the liquid film is relatively thin. The multiple peaks 41 are multiple band-shaped or linear portions surrounding the center of the substrate W. The same applies to the multiple valleys 42. The valley 42 is the portion between two peaks 41 that are adjacent in the radial direction of the substrate W. The peaks 41 and the valleys 42 are concentric with the substrate W. If the same elapsed time is used, the thickness of the peaks 41 is greater than the thickness of the valleys 42.

[0110] When the IPA on the upper surface of the substrate W decreases while the substrate W is rotating around the rotation axis A1, multiple peaks 41 and multiple valleys 42 may form in the IPA liquid film, as shown by the line LB in Figure 9.

[0111] As the amount of IPA decreases from the state indicated by line LB in FIG. 9 , the thicknesses of the peaks 41 and valleys 42 decrease, and the distance between adjacent peaks 41 and valleys 42 in the radial direction of the substrate W increases, as indicated by line LC in FIG. 9 . Therefore, the number of peaks 41 and valleys 42 decreases. As the amount of IPA decreases further, the thicknesses of the peaks 41 and valleys 42 decrease further, and the distance between adjacent peaks 41 and valleys 42 in the radial direction of the substrate W increases further. If this phenomenon continues, one or more valleys 42 will partially or completely disappear, and the upper surface of the substrate W will be exposed from the valleys 42. After that, one or more peaks 41 will partially or completely disappear, and the upper surface of the substrate W will be exposed from the peaks 41.

[0112] FIG. 10 is a conceptual diagram showing the relationship between the moving speed of the gas nozzle 37 and the distribution of IPA on the substrate W. The cross-hatched area in FIG. 10 represents IPA (liquid). The upper side of FIG. 10 shows the distribution of IPA when the moving speed of the gas nozzle 37 is appropriate. The lower left side of FIG. 10 shows a state in which there is residual liquid, as described below. The lower right side of FIG. 10 shows a state in which there is a decrease in liquid, as described below. The IPA nozzle 35 (see FIG. 11) is omitted from FIG. 10.

[0113] If the speed at which the gas nozzle 37 moves from the gas center position to the gas edge position is fast in the hole enlargement step (step S6 in FIG. 4), IPA may remain in an inner portion (in FIG. 10, the inner portion of the circle passing through the gas nozzle 37) that is closer to the rotation axis A1 than the collision position where the gas discharged from the gas nozzle 37 collides with the upper surface of the substrate W. In this case, as shown in the lower left of FIG. 10, multiple IPA peaks 41 and multiple IPA valleys 42 may occur in the inner portion, or only multiple IPA peaks 41 may occur in the inner portion.

[0114] If the speed at which the gas nozzle 37 moves from the gas center position to the gas edge position in the hole enlargement step (step S6 in FIG. 4) is slow, the outer periphery of the upper surface of the substrate W may become exposed from the IPA liquid film before the gas nozzle 37 reaches the gas edge position. In this case, as shown in the lower right of FIG. 10, before the outer periphery of the upper surface of the substrate W becomes exposed from the IPA liquid film, multiple IPA peaks 41 and multiple IPA valleys 42 may appear on the same outer periphery, or only multiple IPA peaks 41 may appear on the same outer periphery.

[0115] In other words, the stage where multiple IPA peaks 41 have appeared on the outer periphery of the upper surface of the substrate W is the stage before the outer periphery of the upper surface of the substrate W is exposed from the IPA liquid film. The presence of multiple IPA peaks 41 on the outer periphery of the upper surface of the substrate W is a sign that the outer periphery of the upper surface of the substrate W will soon be exposed from the IPA liquid film. Therefore, by detecting this, it is possible to predict whether the outer periphery of the upper surface of the substrate W is about to be exposed or when the outer periphery of the upper surface of the substrate W will be exposed.

[0116] When multiple IPA peaks 41 are generated on the upper surface of the substrate W, concentric interference fringes are generated on the upper surface of the substrate W. Furthermore, since the temperature of the peaks 41 is different from the temperature between two peaks 41 (the temperature of the valleys 42 or the substrate W), a concentric temperature distribution occurs on the upper surface of the substrate W in which the temperature alternately rises and falls as the distance from the rotation axis A1 increases.

[0117] Therefore, it is possible to determine whether or not at least one of liquid remaining and liquid reduction has occurred by observing at least one of the appearance and temperature of the upper surface of the substrate W. Liquid remaining is a phenomenon in which IPA remains on the inner portion of the upper surface of the substrate W during the hole enlargement process. Liquid reduction is a phenomenon in which the thickness of the liquid film decreases on the outer periphery of the upper surface of the substrate W before the gas nozzle 37 reaches the gas edge position during the hole enlargement process.

[0118] The spacing between the interference fringes corresponds to the spacing between two adjacent peaks 41 in the radial direction of the substrate W. The spacing between two high-temperature or low-temperature portions also corresponds to the spacing between two adjacent peaks 41 in the radial direction of the substrate W. An increase in this spacing means that the IPA on the substrate W is decreasing. Therefore, by observing at least one of the spacing between the interference fringes and the spacing between two high-temperature or low-temperature portions, it is possible to determine whether the IPA is decreasing.

[0119] Next, the camera 43 and the processing of the substrate W will be described.

[0120] Fig. 11 is a schematic view of the spin chuck 10, the gas nozzle 37, and the camera 43 viewed horizontally. Fig. 12 is a schematic view of the spin chuck 10, the gas nozzle 37, and the camera 43 viewed from above. In Figs. 11 and 12, the IPA nozzle 35 and the gas nozzle 37 are indicated by solid lines when the gas nozzle 37 is located at the gas center position, and the IPA nozzle 35 and the gas nozzle 37 are indicated by two-dot chain lines when the gas nozzle 37 is located at the gas edge position.

[0121] 11 and 12, the substrate processing apparatus 1 is provided with a camera 43 that captures an image of the upper surface of the substrate W held by the spin chuck 10. The camera 43 may be any of a visible light camera, an infrared camera, and a thermograph, or may be other cameras.

[0122] A visible light camera is a camera that generates an image by converting visible light into an electrical signal. An infrared camera and a thermograph are cameras that generate an image by converting infrared light into an electrical signal. A visible light camera and an infrared camera are cameras that generate an image of the appearance of a subject, such as a substrate W. A thermograph is a camera that generates an image that shows the temperature distribution of a subject.

[0123] The camera 43 is disposed in the chamber 4. The camera 43 is disposed above the substrate W held by the spin chuck 10. The camera 43 may be attached to the partition wall 5 of the chamber 4, or may be attached to a member inside the chamber 4 other than the partition wall 5. The camera 43 may photograph the entire upper surface of the substrate W, or may photograph a portion of the upper surface of the substrate W including the central and outer periphery of the upper surface of the substrate W.

[0124] FIG. 13 is a flowchart for explaining another example of processing of the substrate W performed by the substrate processing apparatus 1. In FIG.

[0125] The control device 3 (see FIG. 11) processes the substrate W in the same manner as in the first embodiment. The hole enlargement step according to the second embodiment is the same as the hole enlargement step according to the first embodiment (step S6 in FIG. 4) except that the camera 43 is caused to photograph the top surface of the substrate W. The steps according to the second embodiment other than the hole enlargement step are the same as those according to the first embodiment. Therefore, the hole enlargement step according to the second embodiment will be described below.

[0126] The control device 3 starts an imaging process in which the camera 43 images the top surface of the substrate W (step S11 in FIG. 13). Thereafter, the control device 3 causes the gas nozzle 37 located at the gas center position to start discharging inert gas (step S12 in FIG. 13). Thereafter, the control device 3 causes the IPA nozzle 35 to stop discharging IPA and causes the gas nozzle 37 to move horizontally from the gas center position toward the gas edge position while the substrate W is rotating (step S13 in FIG. 13). Scanning in FIG. 13 refers to the movement of the gas nozzle 37.

[0127] While the gas nozzle 37 is moving toward the gas edge position, the control device 3 performs an image determination step of determining whether or not a liquid residue (a phenomenon in which IPA remains on the inner portion of the upper surface of the substrate W) has occurred, based on an image generated by the camera 43 (step S14 in FIG. 13). The control device 3 further performs an image determination step of determining whether or not a liquid decrease (a phenomenon in which the thickness of the liquid film decreases on the outer periphery of the upper surface of the substrate W before the gas nozzle 37 reaches the gas edge position) has occurred, based on an image generated by the camera 43, while the gas nozzle 37 is moving toward the gas edge position (step S15 in FIG. 13). The control device 3 may determine whether or not a liquid decrease has occurred before determining whether or not a liquid residue has occurred, or may simultaneously determine whether or not a liquid residue and a liquid decrease have occurred.

[0128] When the control device 3 determines based on the image from the camera 43 that concentric interference fringes or a concentric temperature distribution have occurred in the inner portion of the upper surface of the substrate W, it determines that residual liquid has occurred (Yes in step S14 of FIG. 13). Similarly, when the control device 3 determines based on the image from the camera 43 that concentric interference fringes or a concentric temperature distribution have occurred in the outer periphery of the upper surface of the substrate W, it determines that a liquid decrease has occurred (Yes in step S15 of FIG. 13).

[0129] In the example shown in FIG. 13, when the control device 3 determines that no remaining liquid has occurred (No in step S14 in FIG. 13), it determines whether or not a decrease in liquid has occurred (step S15 in FIG. 13). When the control device 3 determines that no decrease in liquid has occurred (No in step S15 in FIG. 13), it moves the gas nozzle 37 to the gas edge position and stops it at that position (step S16 in FIG. 13). Thereafter, the control device 3 stops the gas nozzle 37 from discharging the inert gas (step S17 in FIG. 13). Thereafter, the control device 3 stops the photographing process (step S18 in FIG. 13). As a result, the outer edge HLe of the exposure hole HL (see FIG. 10) expands to the outer periphery of the top surface of the substrate W, and all of the IPA liquid film is discharged from the substrate W.

[0130] When the control device 3 determines that residual liquid has occurred (Yes in step S14 of FIG. 13 ), the control device 3 may perform a speed maintaining step in which the gas nozzle 37 reaches the gas edge position without changing the moving speed of the gas nozzle 37, that is, while moving the gas nozzle 37 at the planned speed. FIG. 13 shows an example of performing the speed maintaining step. In this case, the control device 3 may continue to cause the camera 43 to capture images of various parts of the upper surface of the substrate W while performing the speed maintaining step. When processing another substrate W after determining that residual liquid has occurred in step S14 of FIG. 13 , the control device 3 may perform a speed reducing step in which the moving speed of the gas nozzle 37 is reduced in the hole enlargement step (step S19 of FIG. 13 ). The next scan speed in FIG. 13 refers to the moving speed of the gas nozzle 37 when performing the hole enlargement step on the next substrate W. The speed reducing step is an example of a speed changing step.

[0131] When the control device 3 determines that a liquid decrease is occurring (Yes in step S15 of FIG. 13), it may perform the speed maintaining step described above, or may increase the speed at which the gas nozzle 37 moves so that the gas nozzle 37 reaches the gas edge position before the outer periphery of the top surface of the substrate W is exposed. FIG. 13 shows an example of performing the speed maintaining step. In either case, the control device 3 may continue to have the camera 43 capture images of various parts of the top surface of the substrate W until the gas nozzle 37 reaches the gas edge position.

[0132] When the control device 3 determines that a liquid decrease has occurred (Yes in step S15 of FIG. 13), it may record the liquid decrease start time based on the time when the image indicating that a liquid decrease has occurred was generated (step S20 of FIG. 13). The liquid decrease start time is the time from when the gas nozzle 37 starts to move from the gas center position to when a liquid decrease occurs. The liquid decrease start time is the difference between the time when the gas nozzle 37 starts to move from the gas center position and the time when the image indicating that a liquid decrease has occurred was generated.

[0133] When the control device 3 records the liquid reduction start time, the control device 3 may have a clock or timer. Fig. 11 shows an example in which a clock 44 is provided in each of the control device 3 and the camera 43. When the clock 44 is provided in the camera 43, the camera 43 may add information about the time at which an image of a subject, such as the substrate W, was captured to the image of the subject. In this way, the control device 3 can confirm the time at which the image was generated by referring to the image of the camera 43.

[0134] When processing another substrate W after determining that a liquid decrease has occurred in step S15 of FIG. 13, the control device 3 may perform a speed increase step of increasing the speed at which the gas nozzle 37 moves (step S21 of FIG. 13). The speed increase step is an example of a speed change step. The speed increase step is a step of setting the speed at which the gas nozzle 37 moves so that the nozzle movement speed, which is the time it takes for the gas nozzle 37 to move from the gas center position to the gas edge position in the hole enlargement step, is equal to or shorter than the liquid decrease start time. If the control device 3 determines that a liquid residue or liquid decrease has occurred after performing the speed decrease step or the speed increase step, the control device 3 may increase or decrease the speed at which the gas nozzle 37 moves in the hole enlargement step when processing another substrate W thereafter.

[0135] Next, the effects of this embodiment will be described.

[0136] In addition to the effects of the first embodiment, the second embodiment can achieve the following effects. Specifically, in this embodiment, the camera 43 captures an image of the upper surface of the substrate W while the exposure hole HL surrounded by the ring-shaped IPA liquid film is being widened. Then, based on the image from the camera 43, it is determined whether or not at least one of concentric interference fringes and a concentric temperature distribution is occurring on the upper surface of the substrate W.

[0137] The residual liquid is a phenomenon in which IPA remains in an inner portion, which is closer to the rotation axis A1 than the collision position where the gas discharged from the gas nozzle 37 collides with the upper surface of the substrate W during the hole enlargement process. The liquid decrease is a phenomenon in which the thickness of the liquid film decreases on the outer periphery of the upper surface of the substrate W before the gas nozzle 37 reaches the gas edge position during the hole enlargement process.

[0138] When residual liquid occurs, multiple concentric peaks 41 with a relatively thick liquid film may form on the inner part of the upper surface of the substrate W. When a decrease in liquid occurs, multiple such peaks 41 may form on the outer periphery of the upper surface of the substrate W. When multiple such peaks 41 form on the upper surface of the substrate W, concentric interference fringes are generated. Furthermore, because the temperature of a peak 41 is different from the temperature between two peaks 41, a concentric temperature distribution occurs on the upper surface of the substrate W in which the temperature alternates between rising and falling as the distance from the rotation axis A1 increases.

[0139] The occurrence of concentric interference fringes means that residual liquid or a decrease in liquid has occurred. The same applies to the occurrence of a concentric temperature distribution. Therefore, by determining whether at least one of concentric interference fringes and a concentric temperature distribution has occurred on the top surface of the substrate W, it is possible to determine whether residual liquid or a decrease in liquid has occurred. This allows the substrate W to be processed while checking whether it is being processed as intended.

[0140] In this embodiment, it is determined based on the image from the camera 43 whether at least one of concentric interference fringes and a concentric temperature distribution is occurring on the upper surface of the substrate W. This determines whether IPA remains inside the position where the gas discharged from the gas nozzle 37 collides with the upper surface of the substrate W. Therefore, even if the amount of remaining IPA is small, it is possible to determine whether IPA remains inside the upper surface of the substrate W.

[0141] In this embodiment, it is determined based on the image from the camera 43 whether at least one of concentric interference fringes and a concentric temperature distribution is occurring on the top surface of the substrate W. This determines whether the thickness of the liquid film is decreasing at the outer periphery of the top surface of the substrate W before the gas nozzle 37 reaches the gas edge position. Liquid decrease is a phenomenon that occurs before the outer periphery of the top surface of the substrate W is exposed from the IPA liquid film. In other words, liquid decrease is a phenomenon that occurs before the outer diameter of the ring-shaped IPA liquid film becomes smaller than the diameter of the substrate W. Therefore, by detecting liquid decrease based on the image from the camera 43, it is possible to detect a sign of exposure of the outer periphery of the top surface of the substrate W.

[0142] In this embodiment, when it is determined that at least one of concentric interference fringes and a concentric temperature distribution is occurring on the top surface of the substrate W, the gas nozzle 37 is moved to the gas edge position at the planned speed, rather than changing the planned speed. If the planned speed is changed, the change in the speed of the gas nozzle 37 will affect the phenomena occurring on the top surface of the substrate W. Therefore, such effects can be eliminated, and the phenomena occurring on the top surface of the substrate W can be captured by the camera 43 until the gas nozzle 37 reaches the gas edge position.

[0143] On the other hand, when the hole enlargement process is performed again, the speed at which the gas nozzle 37 moves (nozzle movement speed) is changed based on the determination made using the image from the camera 43. One of the causes of residual liquid is a slow nozzle movement speed. One of the causes of liquid reduction is a fast nozzle movement speed. Therefore, if it is determined that residual liquid has occurred, the nozzle movement speed is decreased. If it is determined that liquid reduction has occurred, the nozzle movement speed is increased.

[0144] In this way, when it is determined that at least one of concentric interference fringes and a concentric temperature distribution is occurring on the top surface of the substrate W, the substrate W is observed until the hole enlargement process is completed without changing the planned speed. When performing the hole enlargement process on the next substrate W, the gas nozzle 37 is moved from the gas center position to the gas edge position at a speed different from the speed used in the previous hole enlargement process. Therefore, control of the phenomenon occurring on the top surface of the substrate W can be simplified compared to when the planned speed is changed midway.

[0145] Next, another embodiment will be described.

[0146] At least one of the IPA nozzle 35 and the gas nozzle 37 may discharge at least one of the IPA and the gas in a direction inclined with respect to the upper surface of the substrate W. Figure 14 shows an example in which the gas nozzle 37 discharges the gas in a direction inclined with respect to the upper surface of the substrate W.

[0147] 14, the lower end of the gas nozzle 37 is inclined toward the gas edge position (the position indicated by the two-dot chain line). The position at which the gas discharged from the gas nozzle 37 shown in Fig. 14 collides with the upper surface of the substrate W may be the same as or different from the position at which the IPA discharged from the IPA nozzle 35 collides with the upper surface of the substrate W. Fig. 14 shows the former example.

[0148] 15 shows, by a two-dot chain line, a state in which the gas nozzle 37 is positioned at the gas edge position. When the gas nozzle 37 is positioned at the gas edge position, the IPA nozzle 35 and the gas nozzle 37 may be positioned so that the gas nozzle 37 is positioned outside the IPA nozzle 35, that is, so that the gas nozzle 37 is positioned on the opposite side of the rotation axis A1 of the substrate W with respect to the IPA nozzle 35. In this case, the horizontal distance between the IPA nozzle 35 and the guard 24 can be increased compared to when the gas nozzle 37 is positioned inside the IPA nozzle 35.

[0149] The IPA nozzle 35 may be connected to a nozzle actuator other than the nozzle actuator 38a that moves the gas nozzle 37, or may be a fixed nozzle. In the former case, when discharging the IPA liquid film from the upper surface of the substrate W, the IPA nozzle 35 may be moved so that the relative positions of the IPA nozzle 35 and the gas nozzle 37 are maintained constant, or at least one of the IPA nozzle 35 and the gas nozzle 37 may be moved so that the relative positions of the IPA nozzle 35 and the gas nozzle 37 change. In the latter case, the IPA nozzle 35 may be kept waiting at a waiting position.

[0150] 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.

[0151] Any two or more of the above-described configurations may be combined. Any two or more of the above-described steps may be combined.

[0152] 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. [Explanation of symbols]

[0153] 1: substrate processing apparatus, 10: spin chuck, 11: chuck pin, 14: spin motor, 35: IPA nozzle, 36f: flow rate adjustment valve, 36h: heater, 36p: IPA pipe, 36v: IPA valve, 37: gas nozzle, 38: nozzle arm, 38a: nozzle actuator, 38f: flow rate adjustment valve, 38p: gas pipe, 38v: gas valve, 41: peak, 42: valley, 43: camera, 44: clock, A1: rotation axis, HL: exposure hole, HLe: outer edge, L1: first boundary line, L2: second boundary line, L3: third boundary line, L4: fourth boundary line, L5: approximation line, W: substrate

Claims

1. a liquid film forming step of discharging IPA (isopropyl alcohol) from an IPA nozzle onto an upper surface of the substrate while rotating the substrate around a vertical rotation axis passing through a center of the substrate, the upper surface of the substrate being held horizontally, to form a liquid film of the IPA. a hole forming step of forming an exposure hole in the center of the liquid film, exposing the center of the upper surface of the substrate, by discharging gas from a gas nozzle toward the center of the upper surface of the substrate while rotating the substrate around the rotation axis in a state where the IPA nozzle stops discharging the IPA; a hole enlargement process for enlarging an outer edge of the exposed hole to the outer periphery of the top surface of the substrate by horizontally moving the gas nozzle from a gas center position where the gas discharged from the gas nozzle collides with the center part of the top surface of the substrate to a gas edge position where the gas discharged from the gas nozzle collides with the outer periphery of the top surface of the substrate while the substrate is rotating around the rotation axis, the IPA nozzle has stopped discharging the IPA, and the gas nozzle is discharging gas toward the top surface of the substrate.

2. a photographing step of photographing the top surface of the substrate with a camera while the gas nozzle is moving toward the gas edge position in the hole enlarging step, thereby generating an image with the camera; 2. The substrate processing method of claim 1, further comprising an image determination step of determining, based on the image, whether at least one of concentric interference fringes and a concentric temperature distribution in which temperature increases and decreases alternately as the distance from the rotation axis increases is occurring on the top surface of the substrate.

3. 3. The substrate processing method of claim 2, wherein the image assessment process includes a process for determining whether or not at least one of the interference fringes and the temperature distribution occurs on the top surface of the substrate based on the image, thereby determining whether or not a liquid residue of the IPA remains in an inner portion that is closer to the rotation axis than the collision position where the gas ejected from the gas nozzle collides with the top surface of the substrate in the hole enlargement process.

4. the hole enlarging step is a step of horizontally moving the gas nozzle from the gas center position to the gas edge position at a nozzle moving speed; The substrate processing method includes: a speed maintaining step of moving the gas nozzle to the gas edge position while causing the camera to capture an image of the top surface of the substrate without changing the nozzle movement speed when it is determined in the image determining step that at least one of the interference fringes and the temperature distribution is occurring; 4. The substrate processing method according to claim 3, further comprising a speed change process of changing the nozzle movement speed when performing the hole enlargement process on another substrate after determining that at least one of the interference fringes and the temperature distribution is occurring in the image determination process.

5. 4. The substrate processing method of claim 3, wherein the image assessment process includes a process for determining whether or not at least one of the interference fringes and the temperature distribution occurs on the top surface of the substrate based on the image, thereby determining whether or not a liquid decrease occurs in the thickness of the liquid film at the outer periphery of the top surface of the substrate before the gas nozzle reaches the gas edge position in the hole enlargement process.

6. 3. The substrate processing method of claim 2, wherein the image assessment process includes a process for determining whether at least one of the interference fringes and the temperature distribution occurs on the top surface of the substrate based on the image, thereby determining whether a liquid reduction occurs in the thickness of the liquid film at the outer periphery of the top surface of the substrate before the gas nozzle reaches the gas edge position in the hole enlargement process.

7. the hole enlarging step is a step of horizontally moving the gas nozzle from the gas center position to the gas edge position at a nozzle moving speed; The substrate processing method includes: a speed maintaining step of moving the gas nozzle to the gas edge position while causing the camera to capture an image of the top surface of the substrate without changing the nozzle movement speed when it is determined in the image determining step that at least one of the interference fringes and the temperature distribution is occurring; 7. The substrate processing method according to claim 6, further comprising a speed change process of changing the nozzle movement speed when performing the hole enlargement process on another substrate after determining that at least one of the interference fringes and the temperature distribution is occurring in the image determination process.

8. 8. A substrate processing method according to claim 1, wherein the moving speed of the gas nozzle in the hole enlarging process is a speed at which the outer edge of the exposed hole reaches the outer periphery of the top surface of the substrate before the outer periphery is exposed from the liquid film due to rotation of the substrate.

9. A substrate processing method according to any one of claims 1 to 7, wherein the moving speed of the gas nozzle in the hole enlargement process is set so that the boundary between the liquid film and the outer edge of the exposed hole is always within an atmosphere formed by the gas nozzle.

10. In an xy coordinate system in which the x-axis represents the rotation speed of the substrate and the y-axis represents the movement speed of the gas nozzle, the combination of the rotation speed of the substrate and the movement speed of the gas nozzle in the hole enlarging step belongs to a region from a line represented by the following formula (1) to a line represented by the following formula (2) when the rotation speed of the substrate is in a range of 300 to 2500 rpm (revolutions per minute): y=0.1209x+39...(1) y=0.0991x-10.65...(2) The substrate processing method according to any one of claims 1 to 7.

11. In the xy coordinate system, a combination of the rotation speed of the substrate and the moving speed of the gas nozzle in the hole enlarging step belongs to a region where a region from the line expressed by the formula (1) to the line expressed by the formula (2) overlaps with a region from the line expressed by the formula (3) to the line expressed by the formula (4) below, when the rotation speed of the substrate is in a range of 300 to 2500 rpm: y=0.1209x+17.1...(3) y=0.1209x-21.35...(4) The substrate processing method according to claim 10.

12. a substrate holder that holds the substrate horizontally; a spin motor that rotates the substrate held by the substrate holder about a vertical rotation axis that passes through a center of the substrate; an IPA nozzle that discharges IPA (isopropyl alcohol) toward an upper surface of the substrate held by the substrate holder while the spin motor is rotating the substrate, thereby covering the entire upper surface of the substrate with a liquid film that is a film of the IPA; a gas nozzle that discharges gas toward a central portion of the upper surface of the substrate held by the substrate holder while the spin motor is rotating the substrate and the IPA nozzle stops discharging the IPA, thereby forming an exposure hole in the central portion of the liquid film, exposing the central portion of the upper surface of the substrate; a nozzle actuator that expands the outer edge of the exposure hole to the outer periphery of the top surface of the substrate by horizontally moving the gas nozzle from a gas center position where the gas discharged from the gas nozzle collides with the center of the top surface of the substrate to a gas edge position where the gas discharged from the gas nozzle collides with the outer periphery of the top surface of the substrate, while the spin motor is rotating the substrate, the IPA nozzle has stopped discharging the IPA, and the gas nozzle is discharging gas toward the top surface of the substrate held by the substrate holder.

Images