WO2024180821A1 - Substrate processing method and substrate processing device - Google Patents

Abstract

Provided is a method for processing a substrate on a main surface of which a resist film has been formed. This method comprises: a nozzle disposition step for disposing a plurality of fluid nozzles so as to face the main surface of the substrate; a supply step for supplying water vapor, ozone gas, and sulfuric acid to the plurality of fluid nozzles; and a mixed fluid supply step for supplying a mixed fluid of the water vapor, the ozone gas, and the sulfuric acid from the plurality of fluid nozzles toward the main surface of the substrate, thereby removing the resist film from the main surface of the substrate. The supply step may comprise a wet ozone gas supply step for supplying wet ozone gas in which water vapor and ozone gas are mixed with each other to the plurality of fluid nozzles.

Description

SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS Related Applications

This application claims priority to Japanese Patent Application No. 2023-028824, filed on February 27, 2023, the entire contents of which are incorporated herein by reference.

This invention relates to a substrate processing method and substrate processing apparatus for processing substrates. Substrates to be processed include, 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, substrates for solar cells, etc.

In the manufacturing process of semiconductor devices, resist (photoresist) is used as a mask for forming patterns on a substrate and implanting ions into active regions. A known wet process for removing used resist from a substrate is one that uses a mixture of sulfuric acid and hydrogen peroxide (SPM). Specifically, as described in Patent Document 1, sulfuric acid and hydrogen peroxide are mixed to generate SPM, which is then supplied to the surface of the substrate to remove the resist on the substrate.

JP 2009-16497 A

Both sulfuric acid and hydrogen peroxide are expensive chemicals, so reducing their usage would reduce substrate processing costs. In addition, sulfuric acid is an environmentally hazardous chemical, so reducing its usage is also required from the perspective of reducing the environmental impact. Research is also being conducted to recover used SPM, regenerate sulfuric acid, and reuse the regenerated sulfuric acid. However, the SPM produced by mixing SPM with hydrogen peroxide contains a large amount of water. Therefore, in order to evaporate the water from the SPM and obtain sulfuric acid of the target concentration, it is necessary to overcome technical and cost challenges.

Therefore, one embodiment of the present invention provides a substrate processing method and substrate processing apparatus that can efficiently remove resist films on substrates while reducing the amount of chemical solution used.

One embodiment of the present invention provides a substrate processing method and substrate processing apparatus having the following exemplary features:

1. A method for treating a substrate having a resist film formed on a main surface thereof, comprising the steps of:
a nozzle arrangement step of arranging a multi-fluid nozzle toward a main surface of the substrate;
a supply step of supplying water vapor, ozone gas, and sulfuric acid to the multiple fluid nozzle;
a mixed fluid supplying step of supplying a mixed fluid of water vapor, ozone gas, and sulfuric acid from the multiple fluid nozzle toward the main surface of the substrate to remove the resist film from the main surface of the substrate;
A method for processing a substrate, comprising:

In this method, a mixed fluid of water vapor, ozone gas, and sulfuric acid (typically sulfuric acid heated to a temperature higher than room temperature) is supplied to the main surface of the substrate, and the mixed fluid removes the resist film from the main surface of the substrate. Heat of dilution is generated when the sulfuric acid comes into contact with the water vapor, and the heat of dilution causes ozone to decompose at the interface of the heated sulfuric acid, generating Caro's acid (peroxomonosulfuric acid). The action of this Caro's acid (particularly active oxygen) breaks down the resist, allowing the resist film to be efficiently removed (peeled off) from the main surface of the substrate.

As this is a process that does not require (use) costly hydrogen peroxide, it is possible to realize a process that is inexpensive and has high stripping performance. In addition, the sulfuric acid contained in the mixed fluid flows down from the substrate as liquid, and this can be recovered and reused. Because the water content in the recovered sulfuric acid is small, the technical and cost barriers to regenerating sulfuric acid of the target concentration from the recovered sulfuric acid are not high. Therefore, because this is a process that makes it easy to reuse sulfuric acid, it is possible to reduce the amount of sulfuric acid used. In this way, it is possible to realize substrate processing that can efficiently remove resist films on substrates while reducing the amount of chemicals used.

2. The substrate processing method described in item 1, wherein the supplying step includes a wet ozone gas supplying step of supplying wet ozone gas, which is a mixture of water vapor and ozone gas, to the multiple fluid nozzle.

When the wet ozone gas comes into contact with sulfuric acid in the multiple fluid nozzle, heat of dilution is generated by the moisture (water vapor) in the wet ozone gas, and the ozone can be brought into contact with the interface of the sulfuric acid heated by the heat of dilution. This allows Caro's acid to be efficiently generated, and the Caro's acid immediately after generation can be supplied to the main surface of the substrate to react with the resist film. This allows for efficient resist removal processing.

3. The substrate processing method according to item 2, wherein the wet ozone gas supply process includes a wet ozone gas generation process in which ozone gas is bubbled in water to generate wet ozone gas.

Wet ozone gas can be produced in a simple manner by bubbling ozone gas through water (typically deionized water).

In addition, wet ozone gas can be generated by mixing water vapor with ozone gas. However, since ozone gas decomposes at approximately 130°C, it is preferable to mix it with water vapor at a temperature that can avoid decomposition. When generating wet ozone gas by bubbling in water, the boiling point of water is lower than the decomposition temperature of ozone gas, so temperature control to avoid decomposition of ozone gas is not necessary.

The water through which the ozone gas is bubbled may be heated. Bubbling in the heated water can encourage the generation of water vapor, producing moist ozone gas containing a moderate amount of water vapor that can be pumped to the multiple-fluid nozzle.

4. The substrate processing method described in item 2, wherein the wet ozone gas supplying step includes a step of bubbling ozone gas supplied from an ozone gas supply source in water in a closed space to generate wet ozone gas in the closed space, and pressure-feeding the wet ozone gas from the closed space to the multiple fluid nozzle.

By supplying ozone gas into water contained in a closed space and bubbling it, wet ozone gas can be generated and pumped out, and fluid mixing can be performed in a multiple fluid nozzle with a simple configuration.

5. The substrate processing method according to any one of claims 1 to 4, wherein the mixed fluid supply step supplies the mixed fluid containing Caro's acid produced by mixing the ozone gas and the sulfuric acid toward the main surface of the substrate.

By supplying a mixed fluid containing Caro's acid to the main surface of the substrate, the resist on the substrate can be broken down and efficiently removed.

6. The substrate processing method according to item 5, wherein the mixed fluid supply step supplies the mixed fluid containing the Caro's acid, which is hotter than the sulfuric acid, toward the main surface of the substrate by heat of dilution generated by contact between the water vapor and the sulfuric acid.

Due to the heat of dilution generated by mixing water vapor and sulfuric acid, the Caro's acid supplied to the main surface of the substrate becomes hotter than the sulfuric acid. This promotes the decomposition of the resist on the substrate, allowing the resist film to be removed efficiently.

7. The substrate processing method according to any one of claims 1 to 6, wherein the water vapor supplied to the multiple fluid nozzle is at or below 100°C.

By keeping the temperature of the water vapor at 100°C or less, which is lower than the decomposition temperature of ozone, it is possible to prevent the ozone from decomposing before coming into contact with sulfuric acid. This allows Caro's acid to be generated efficiently when the ozone gas comes into contact with sulfuric acid, achieving high resist removal performance.

8. The substrate processing method according to any one of claims 1 to 7, wherein the main surface of the substrate is a dry surface without a liquid film before the mixed fluid is supplied in the mixed fluid supplying step.

By supplying the mixed fluid to a dry main surface with no liquid film, the Caro's acid in the mixed fluid acts on the resist film without being diluted. This allows the resist decomposition reaction by Caro's acid to occur efficiently, enabling highly efficient resist removal.

9. The method further includes a substrate rotation step of rotating the substrate about a rotation axis passing through the main surface,
9. The substrate processing method according to any one of items 1 to 8, wherein the mixed fluid supplying step is performed in parallel with the substrate rotating step, and includes a scanning step of discharging the mixed fluid from the multiple-fluid nozzle while moving a landing point of the mixed fluid on the main surface from an outer periphery of the substrate toward the rotation axis.

When the substrate rotates, the liquid on the main surface of the substrate flows toward the outer periphery due to centrifugal force. Therefore, by starting the scanning of the main surface of the substrate with the mixed fluid discharged from the multi-fluid nozzle from the outer edge of the substrate, the mixed fluid is supplied to a surface that is essentially free of liquid film. As a result, the Caro's acid in the mixed fluid acts on the resist film on the main surface of the substrate without being diluted, achieving highly efficient resist removal.

10. The substrate processing method according to any one of claims 1 to 9, wherein the resist film on the main surface of the substrate is removed without contacting the sulfuric acid with hydrogen peroxide solution.

Since there is no contact between the sulfuric acid and hydrogen peroxide, it is possible to avoid mixing a large amount of water into the sulfuric acid. This reduces the amount of processing required to remove the water from the sulfuric acid, making it easier to regenerate and reuse the sulfuric acid, and therefore reducing the amount of sulfuric acid used.

11. A substrate holding unit that holds a substrate;
a multi-fluid nozzle arranged to face a main surface of a substrate held by the substrate holding unit;
a water vapor/ozone supply unit for supplying water vapor and ozone gas to the multiple fluid nozzle;
a sulfuric acid supply unit for supplying sulfuric acid (typically sulfuric acid heated above room temperature) to the multi-fluid nozzle;
a substrate processing apparatus configured to supply a mixed fluid of water vapor, ozone gas, and sulfuric acid from the multiple fluid nozzle toward a main surface of a substrate held by the substrate holding unit.

12. The substrate processing apparatus according to item 11, wherein the water vapor/ozone supply unit supplies wet ozone gas, which is a mixed gas of water vapor and ozone gas.

13. The substrate processing apparatus according to item 12, wherein the water vapor/ozone supply unit includes a wet ozone gas generation unit that generates the wet ozone gas by bubbling ozone gas in water.

14. The substrate processing apparatus described in item 13, wherein the wet ozone gas generation unit includes a sealed container that forms a closed space and an ozone gas supply unit that supplies ozone gas into the water stored in the sealed container, and pressure-feeds the wet ozone gas toward the multiple fluid nozzle.

15. The features described in paragraphs 11 to 14 may be combined with one or more of the features described above with respect to the substrate processing method.

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

FIG. 1 is a schematic plan view for explaining an example of the configuration of a substrate processing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the configuration of a processing unit provided in the substrate processing apparatus. FIG. 3 shows an example of the configuration of a supply system for supplying a mixed fluid of water vapor, ozone gas, and sulfuric acid. FIG. 4 is a block diagram for explaining the electrical configuration of the substrate processing apparatus. FIG. 5 is a flow chart for explaining an example of the substrate processing. FIG. 6A is a schematic diagram for explaining the state of a substrate and its surroundings during substrate processing, showing a nozzle arrangement step. FIG. 6B is a schematic diagram for explaining the state of the substrate and its surroundings during substrate processing, showing a mixed fluid supplying step. FIG. 6C is a schematic diagram for explaining the state of the substrate and its surroundings during substrate processing, showing a rinsing step. FIG. 7 shows an example of the scanning process (step S52 in FIG. 5). FIG. 8 is a diagram for explaining the configuration of a mixed fluid supply system in another embodiment of the present invention.

FIG. 1 is a schematic plan view for explaining an example of the configuration of a substrate processing apparatus 1 according to one embodiment of the present invention. The substrate processing apparatus 1 is a single-wafer type apparatus that processes substrates W one by one. In this embodiment, the substrate W has a disk shape. The substrate W is a substrate W such as a silicon wafer, and has a pair of main surfaces.

The substrate processing apparatus 1 includes a plurality of processing units 2 for processing substrates W, a load port LP (container holding unit) on which a carrier C (container) is placed that contains a plurality of substrates W to be processed in the processing units 2, transport robots (first transport robot IR and second transport robot CR) that transport the substrates W between the load port LP and the processing units 2, and a controller 3 that controls each component provided in the substrate processing apparatus 1.

The first transport robot IR transports substrates W between the carrier C and the second transport robot CR. The second transport robot CR transports substrates W between the first transport robot IR and the processing unit 2. Each transport robot is, for example, a multi-joint arm robot.

The multiple processing units 2 are arranged on both sides of the transport path TR along which the substrate W is transported by the second transport robot CR, and are stacked vertically. The multiple processing units 2 have, for example, the same configuration. The multiple processing units 2 form four processing towers TW arranged at four horizontally spaced positions. Each processing tower TW includes multiple processing units 2 stacked vertically. The four processing towers TW are arranged, two on each side, of the transport path TR extending from the load port LP toward the second transport robot CR.

The substrate processing apparatus 1 includes a plurality of fluid boxes 4 that house valves, piping, etc., and a storage box 5 that houses tanks for storing sulfuric acid, chemicals, rinsing liquids, organic solvents, or these raw materials. The processing units 2 and fluid boxes 4 are arranged inside a frame 6 that is roughly rectangular in plan view.

The processing unit 2 has a chamber 7 that houses the substrate W during substrate processing. The chamber 7 includes an entrance (not shown) through which the second transport robot CR loads the substrate W into the chamber 7 and loads the substrate W out of the chamber 7, and a shutter unit (not shown) that opens and closes the entrance. Processing liquids supplied to the substrate W in the chamber 7 include sulfuric acid, chemical liquids, rinse liquids, organic solvents, etc., which will be described in detail later.

FIG. 2 is a schematic diagram for explaining the configuration of the processing unit 2. The processing unit 2 includes a spin chuck 8 that rotates the substrate W about a rotation axis A1 while holding the substrate W in a predetermined processing posture, and a number of nozzles (a first mobile nozzle 9, a second mobile nozzle 10, and a third mobile nozzle 11) that eject a processing liquid toward the substrate W.

The processing unit 2 further includes a substrate heating member 14 that heats the substrate W held on the spin chuck 8, and a processing cup 15 that receives processing liquid that splashes from the substrate W held on the spin chuck 8.

The spin chuck 8, multiple moving nozzles, substrate heating member 14, and processing cup 15 are disposed within chamber 7.

The rotation axis A1 passes through the center of the substrate W and is perpendicular to each main surface of the substrate W held in the processing posture. The processing posture is, for example, the posture of the substrate W shown in FIG. 2, which is a horizontal posture in which the main surface of the substrate W is in a horizontal plane, but is not limited to a horizontal posture. In other words, the processing posture may be a posture in which the main surface of the substrate W is inclined relative to the horizontal plane, unlike that shown in FIG. 2. When the processing posture is a horizontal posture, the rotation axis A1 extends vertically.

The spin chuck 8 is an example of a substrate holding member (substrate holding unit, substrate holder) that holds the substrate W in a processing position, and is also an example of a rotating holding member that rotates the substrate W around the rotation axis A1 while holding the substrate W in a processing position.

The spin chuck 8 includes a spin base 21 having a disk shape along the horizontal direction, a plurality of gripping pins 20 that grip the substrate W above the spin base 21 and grip the peripheral portion of the substrate W above the spin base 21, a rotation shaft 22 that is connected to the spin base 21 and extends in the vertical direction, and a rotation drive mechanism 23 that rotates the rotation shaft 22 around its central axis (rotation axis A1). The spin base 21 is an example of a disk-shaped base.

The multiple gripping pins 20 are arranged on the upper surface of the spin base 21 at intervals in the circumferential direction of the spin base 21. The rotation drive mechanism 23 includes an actuator such as an electric motor. The rotation drive mechanism 23 rotates the rotation shaft 22, thereby rotating the spin base 21 and the multiple gripping pins 20 around the rotation axis A1. As a result, the substrate W is rotated around the rotation axis A1 together with the spin base 21 and the multiple gripping pins 20.

The multiple gripping pins 20 are movable between a closed position in which they contact the peripheral edge of the substrate W to grip the substrate W, and an open position in which they release their grip on the substrate W. The multiple gripping pins 20 are moved by an opening/closing mechanism (not shown).

When the multiple gripping pins 20 are in the closed position, they grip the peripheral edge of the substrate W and hold the substrate W horizontally. When the multiple gripping pins 20 are in the open position, they release their grip on the substrate W while supporting the peripheral edge of the substrate W from below. The opening and closing mechanism includes, for example, a link mechanism and an actuator that applies a driving force to the link mechanism.

The multiple mobile nozzles include a first mobile nozzle 9 that ejects a mixed fluid of water vapor, ozone gas, and sulfuric acid toward the top surface (upper main surface) of the substrate W held on the spin chuck 8, a second mobile nozzle 10 that selectively ejects a continuous flow of chemical liquid and a continuous flow of rinsing liquid toward the top surface of the substrate W held on the spin chuck 8, and a third mobile nozzle 11 that ejects an organic solvent toward the top surface of the substrate W held on the spin chuck 8.

The first moving nozzle 9 is an example of a multiple fluid nozzle that supplies a mixed fluid of water vapor, ozone gas, and sulfuric acid toward the main surface (top surface) of the substrate W held by the spin chuck 8. The second moving nozzle 10 is an example of a chemical liquid nozzle that ejects a chemical liquid toward the main surface (top surface) of the substrate W held by the spin chuck 8, and is an example of a rinsing liquid nozzle that ejects a rinsing liquid toward the main surface (top surface) of the substrate W held by the spin chuck 8. The third moving nozzle 11 is an example of an organic solvent nozzle that ejects an organic solvent toward the main surface (top surface) of the substrate W held by the spin chuck 8.

The multiple moving nozzles are each moved horizontally by multiple nozzle driving mechanisms (first nozzle driving mechanism 25, second nozzle driving mechanism 26, and third nozzle driving mechanism 27).

Each nozzle driving mechanism can move the corresponding mobile nozzle between a central position and a retracted position. The central position is a position where the mobile nozzle faces the central region of the top surface of the substrate W. The central region of the top surface of the substrate W is a region on the top surface of the substrate W that includes the center of rotation (central portion) and the area surrounding the center of rotation. The retracted position is a position where the mobile nozzle does not face the top surface of the substrate W, and is a position outside the processing cup 15.

Each nozzle drive mechanism includes an arm (first arm 25a, second arm 26a, and third arm 27a) that supports the corresponding moving nozzle, and an arm drive mechanism (first arm drive mechanism 25b, second arm drive mechanism 26b, and third arm drive mechanism 27b) that moves the corresponding arm in the horizontal direction. Each arm drive mechanism includes an actuator such as an electric motor or an air cylinder.

The moving nozzle may be a rotating nozzle that rotates around a predetermined axis of rotation, or a linear nozzle that moves linearly in the direction in which the corresponding arm extends. The moving nozzle may also be configured to be able to move vertically.

The treatment unit 2 further includes a sulfuric acid supply unit 16 that supplies sulfuric acid to the first moving nozzle 9, and a water vapor/ozone supply unit 13 that supplies water vapor and ozone gas to the first moving nozzle 9. The sulfuric acid supply unit 16 includes a sulfuric acid pipe 40, a sulfuric acid valve 50A, and a sulfuric acid flow rate control valve 50B.

The sulfuric acid piping 40 is connected to the first moving nozzle 9 and guides the sulfuric acid to the first moving nozzle 9. The sulfuric acid valve 50A and the sulfuric acid flow rate control valve 50B are provided in the sulfuric acid piping 40.

The sulfuric acid valve 50A being provided in the sulfuric acid pipe 40 may mean that the sulfuric acid valve 50A is interposed in the sulfuric acid pipe 40. The same applies to the other valves described below.

The sulfuric acid valve 50A opens and closes the flow path in the sulfuric acid pipe 40. The sulfuric acid flow control valve 50B adjusts the flow rate of sulfuric acid flowing through the flow path in the sulfuric acid pipe 40. When the sulfuric acid valve 50A is opened, sulfuric acid is supplied to the first moving nozzle 9 at a flow rate adjusted by the sulfuric acid flow control valve 50B.

Although not shown, sulfuric acid valve 50A includes a valve body with a valve seat inside, a valve element that opens and closes the valve seat, and an actuator that moves the valve element between an open position and a closed position. The other valves have a similar configuration.

In this embodiment, the water vapor/ozone supply unit 13 is a wet ozone gas supply unit that supplies wet ozone gas, which is a mixed gas of water vapor and ozone gas, to the first moving nozzle 9. The water vapor/ozone supply unit 13 has a wet ozone gas pipe 45 connected to the first moving nozzle 9. In this embodiment, the first moving nozzle 9 is configured as a two-fluid nozzle. A mixed fluid is generated by mixing sulfuric acid supplied from the sulfuric acid supply unit 16 and wet ozone gas supplied from the water vapor/ozone supply unit 13 in the two-fluid nozzle that constitutes the first moving nozzle 9. The mixed fluid is ejected toward the upper surface of the substrate W held by the spin chuck 8. The configuration of the water vapor/ozone supply unit 13 will be described later.

The chemical solution discharged from the second moving nozzle 10 may be, for example, an APM solution (ammonia-hydrogen peroxide mixture, more specifically, so-called SC1). In addition, a chemical solution containing hydrofluoric acid (HF), dilute hydrofluoric acid (DHF), buffered hydrofluoric acid (BHF), hydrochloric acid (HCl), HPM solution (hydrochloric acid-hydrogen peroxide mixture), ammonia water, TMAH solution (tetramethylammonium hydroxide solution), or hydrogen peroxide water (H ₂ O ₂ ) may be discharged from the second moving nozzle 10.

The rinse liquid discharged from the second moving nozzle 10 is, for example, water such as deionized water (DIW). However, the rinse liquid is not limited to deionized water, and may be deionized water, carbonated water, electrolytic ionized water, hydrochloric acid water with a dilute concentration (for example, 1 ppm or more and 100 ppm or less), ammonia water with a dilute concentration (for example, 1 ppm or more and 100 ppm or less), reduced water (hydrogen water), or a mixture containing at least two of these.

The second moving nozzle 10 is connected to a common pipe 41 that guides fluid to the second moving nozzle 10. A chemical liquid pipe 42 that supplies a chemical liquid to the common pipe 41 and a rinsing liquid pipe 43 that supplies a rinsing liquid to the common pipe 41 are connected to the common pipe 41. The common pipe 41 may be connected to the chemical liquid pipe 42 and the rinsing liquid pipe 43 via a mixing valve (not shown).

The common pipe 41 is provided with a common valve 51 that opens and closes the common pipe 41. The chemical pipe 42 is provided with a chemical valve 52A that opens and closes the chemical pipe 42, and a chemical flow rate adjustment valve 52B that adjusts the flow rate of the chemical in the chemical pipe 42. The rinsing liquid pipe 43 is provided with a rinsing liquid valve 53A that opens and closes the rinsing liquid pipe 43, and a rinsing liquid flow rate adjustment valve 53B that adjusts the flow rate of the rinsing liquid in the rinsing liquid pipe 43.

When the chemical liquid valve 52A and the common valve 51 are opened, a continuous flow of chemical liquid is discharged from the second moving nozzle 10. When the rinse liquid valve 53A and the common valve 51 are opened, a continuous flow of rinse liquid is discharged from the second moving nozzle 10.

The organic solvent discharged from the third moving nozzle 11 contains at least one of the following: alcohols such as ethanol (EtOH) and isopropanol (IPA); ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether (PGEE); lactate esters such as methyl lactate and ethyl lactate (EL); aromatic hydrocarbons such as toluene and xylene; and ketones such as methyl ethyl ketone, 2-heptanone, and cyclohexanone.

An organic solvent pipe 44 that guides the organic solvent to the third moving nozzle 11 is connected to the third moving nozzle 11. The organic solvent pipe 44 is provided with an organic solvent valve 54A that opens and closes the organic solvent pipe 44, and an organic solvent flow rate adjustment valve 54B that adjusts the flow rate of the organic solvent in the organic solvent pipe 44.

The processing cup 15 includes a plurality of guards 28 (three in FIG. 2) that receive processing liquid splashed outward from the substrate W held by the spin chuck 8, a plurality of cups 29 (three in FIG. 2) that each receive processing liquid guided downward by the plurality of guards 28, and a cylindrical outer wall member 30 that surrounds the plurality of guards 28 and the plurality of cups 29.

Each guard 28 has a cylindrical shape surrounding the spin chuck 8 in a plan view. The upper end of each guard 28 is inclined inward toward the center of the guard 28. Each cup 29 has the shape of an annular groove that opens upward. The multiple guards 28 and the multiple cups 29 are arranged coaxially.

The multiple guards 28 are individually raised and lowered by a guard lifting drive mechanism (not shown). The guard lifting drive mechanism includes, for example, multiple actuators that drive the multiple guards 28 to raise and lower. The multiple actuators include at least one of an electric motor and an air cylinder.

The processing unit 2 includes a blower unit 31, such as an FFU (fan filter unit), that sends an inert gas from outside the chamber 7 into the chamber 7, and an exhaust pipe 32 that exhausts the air from inside the chamber 7. The blower unit 31 is disposed on the upper wall 7a of the chamber 7. The exhaust pipe 32 is connected to the outer wall member 30. The inert gas sent to the chamber 7 by the blower unit 31 may be, for example, nitrogen gas, a rare gas, or a mixture of these. The rare gas is, for example, argon gas.

The exhaust pipe 32 is connected to an exhaust duct (not shown). The atmosphere in the exhaust duct is sucked in by a suction device (not shown). The atmosphere in the chamber 7 is exhausted to the exhaust duct via the exhaust pipe 32. The suction device includes a suction pump that sucks the exhaust duct. The suction device is installed in the exhaust duct or connected to the exhaust duct. The exhaust duct and the suction device are provided in a clean room in which the substrate processing apparatus 1 is installed or in a facility associated with the clean room. The exhaust duct and the suction device may be part of the substrate processing apparatus 1.

An ozone remover 33 (ozone detoxifier) is provided between the exhaust pipe 32 and the exhaust duct, or in the exhaust pipe 32. The ozone gas contained in the atmosphere exhausted from the chamber 7 is decomposed as it passes through the ozone remover 33.

By the action of the blower unit 31 and the exhaust pipe 32, an air current moving from top to bottom is formed in the internal space 7c of the chamber 7. The air current passes through the inside of the processing cup 15 and flows into the exhaust pipe 32.

The processing liquid supplied to the substrate W splashes off the periphery of the substrate W and is received by one of the guards 28. The processing liquid received by the guard 28 is guided to the corresponding cup 29 and is collected or discarded through the drainage pipe 35 corresponding to each cup 29.

The substrate heating member 14 has the form of a disk-shaped hot plate that heats the substrate W from below. The substrate heating member 14 is disposed between the upper surface of the spin base 21 and the lower surface of the substrate W. The substrate heating member 14 has a heating surface 14a that faces the lower surface of the substrate W from below.

The substrate heating member 14 includes a plate body 60 and a heater 61. The plate body 60 is slightly smaller than the substrate W in a plan view. The upper surface of the plate body 60 constitutes the heating surface 14a. The heater 61 may be a resistor built into the plate body 60. The heating surface 14a is heated by passing electricity through the heater 61.

The heater 61 is configured to heat the substrate W at a temperature range above room temperature (for example, a temperature of 5°C or higher and 25°C or lower) and, for example, below 400°C.

The processing unit 2 further includes a temperature sensor 62 that detects the temperature of the substrate heating member 14. In the example shown in FIG. 2, the temperature sensor 62 is built into the plate body 60, but the arrangement of the temperature sensor 62 is not particularly limited. The temperature sensor 62 may be attached to the plate body 60 from the outside, for example.

The heater 61 is connected to a current supply unit 63 via a power supply line 64. The temperature of the heater 61 is adjusted by adjusting the current supplied from the current supply unit 63 to the heater 61. For example, the current supplied from the current supply unit 63 to the heater 61 is adjusted based on the temperature detected by the temperature sensor 62.

A heater lift shaft 65 is connected to the underside of the substrate heating member 14. The heater lift shaft 65 is inserted into a through hole 21a formed in the center of the spin base 21 and into the internal space of the rotation shaft 22.

The processing unit 2 further includes a heater drive mechanism 66 that drives the movement of the substrate heating member 14 in the vertical direction. The heater drive mechanism 66 includes, for example, a heater actuator (not shown) that drives the movement of the heater lift shaft 65 in the vertical direction. The heater actuator includes, for example, at least one of an electric motor and an air cylinder. The heater drive mechanism 66 moves the substrate heating member 14 in the vertical direction via the heater lift shaft 65. The substrate heating member 14 is movable in the vertical direction between the lower surface of the substrate W and the upper surface of the spin base 21.

When the substrate heating member 14 rises, it can receive the substrate W from the multiple gripping pins 20 that are positioned in the open position. The substrate heating member 14 can heat the substrate W by being positioned at a contact position where the heating surface 14a is in contact with the underside of the substrate W, or at a proximity position where the heating surface 14a is in close proximity to the underside of the substrate W but not in contact with it. A position where the substrate heating member 14 is sufficiently retracted from the underside of the substrate W so that the heating of the substrate W by the substrate heating member 14 is alleviated is called a retracted position. The fact that the heating of the substrate W is sufficiently alleviated can be said to be another way of saying that the heating of the substrate W is stopped.

The amount of heat transferred from the substrate heating member 14 to the substrate W when the substrate heating member 14 is located in the retracted position is smaller than the amount of heat transferred from the substrate heating member 14 to the substrate W when the substrate heating member 14 is located in the close position. The contact position and close position are also called heating positions. The retracted position is also called the heating relaxation position or heating stop position.

FIG. 3 shows an example of the configuration of a supply system for supplying a mixed fluid of water vapor, ozone gas, and sulfuric acid. In this example, the mixed fluid supply system includes a sulfuric acid supply unit 16, a water vapor/ozone supply unit 13, and a first moving nozzle 9 consisting of a multiple-fluid nozzle (a two-fluid nozzle in this example).

The sulfuric acid supply unit 16 includes a sulfuric acid pipe 40 that flows sulfuric acid from a sulfuric acid tank 55, which is a sulfuric acid supply source, to the first moving nozzle 9, a sulfuric acid valve 50A that is installed in the sulfuric acid pipe 40, and a sulfuric acid flow rate control valve 50B that is also installed in the sulfuric acid pipe 40. It is preferable that the sulfuric acid flow rate control valve 50B adjusts the flow rate of sulfuric acid in the sulfuric acid pipe 40 to 1 liter/minute or less. Furthermore, in this example, the sulfuric acid supply unit 16 includes a filter 50C, a pump 50D, and a heater unit 50E that are installed in the sulfuric acid pipe 40. The pump 50D pumps sulfuric acid from the sulfuric acid tank 55 and sends it from the sulfuric acid pipe 40 to the first moving nozzle 9. The filter 50C removes foreign matter in the sulfuric acid flowing through the sulfuric acid pipe 40. The heater unit 50E heats the sulfuric acid that is supplied to the first moving nozzle 9 through the sulfuric acid pipe 40. The heater unit 50E heats the sulfuric acid so that the temperature of the sulfuric acid when it reaches the first moving nozzle 9 is 120°C or higher and 190°C or lower.

The sulfuric acid supplied by the sulfuric acid supply unit 16 is, strictly speaking, a sulfuric acid-containing liquid, typically a sulfuric acid aqueous solution of a predetermined concentration, containing sulfuric acid (H ₂ SO ₄ ) and water (H ₂ O). The sulfuric acid aqueous solution is, for example, dilute sulfuric acid or concentrated sulfuric acid. The sulfuric acid-containing liquid may be an aqueous sulfuric acid solution prepared by mixing sulfuric acid with water such as deionized water. The sulfuric acid-containing liquid may contain substances other than sulfuric acid and water, but in this embodiment, at least hydrogen peroxide water is not contained. In this specification, "sulfuric acid" means the sulfuric acid-containing liquid as described above.

The water vapor/ozone supply unit 13 includes a wet ozone gas generation unit 56 that generates wet ozone gas by bubbling ozone gas in water, and a wet ozone gas pipe 45 that supplies the wet ozone gas generated by the wet ozone gas generation unit 56 to the first moving nozzle 9. The wet ozone gas generation unit 56 includes an airtight container 57 that forms an enclosed space, and an ozone gas supply unit 58 that supplies ozone gas into water (e.g., deionized water) stored in the airtight container 57. In this embodiment, the wet ozone gas generation unit 56 further includes a heater unit 59 that heats the water stored in the airtight container 57. The heater unit 59 may be configured to heat the airtight container 57. The ozone gas supply unit 58 includes an ozone gas pipe 70 that distributes ozone gas from an ozone gas supply source to the sealed container 57, an ozone gas valve 70A (on/off valve) provided in the ozone gas pipe 70, and an ozone gas flow rate adjustment valve 70B provided in the ozone gas pipe 70. The ozone gas pipe 70 may further be provided with a filter 70C for removing foreign matter. The tip of the ozone gas pipe 70 is placed in the water stored in the sealed container 57.

When the ozone gas valve 70A is opened, ozone gas flows through the ozone gas pipe 70 at a flow rate (for example, 1 to 2 liters/min) regulated by the ozone gas flow rate control valve 70B, and is released into the water stored in the sealed container 57. This allows the ozone gas to bubble in the water. As a result, water vapor is mixed with the ozone gas to generate wet ozone gas (wet ozone gas generation process). The inlet of the wet ozone gas pipe 45 opens in the sealed container 57 and is disposed in a closed space above the water level of the water stored in the sealed container 57. Therefore, the wet ozone gas generated in the sealed container 57 is guided through the wet ozone gas pipe 45 to the first moving nozzle 9. By continuing to supply ozone gas from the ozone gas supply unit 58 to the sealed container 57, the air pressure in the sealed container 57 increases, and the wet ozone gas can be pressure-fed from the sealed container 57 to the first moving nozzle 9 via the wet ozone gas pipe 45.

The water in the sealed container 57 is heated by the heater unit 59, and the water temperature is kept higher than room temperature (for example, room temperature to 80°C), which promotes evaporation of the water, and thus produces wet ozone gas in which water vapor is mixed with ozone gas at an appropriate ratio. It is preferable to keep the temperature of the water stored in the sealed container 57 below 100°C to prevent decomposition of the ozone gas.

The first moving nozzle 9 may be configured as, for example, an external mixing type two-fluid nozzle. More specifically, the first moving nozzle 9 has a nozzle housing 90 and a first passage 91 and a second passage 92 formed in the nozzle housing 90. The first passage 91 is connected to the sulfuric acid pipe 40, and the second passage 92 is connected to the wet ozone gas pipe 45. At the tip of the nozzle housing, a first outlet 91a for discharging a fluid (sulfuric acid in this example) that has flowed through the first passage 91 and a second outlet 92a for discharging a fluid (wet ozone gas in this example) that has flowed through the second passage 92 are opened. The fluids discharged from the first outlet 91a and the second outlet 92a collide and mix outside the nozzle housing 90 near the outlets 91a and 92a, generating a mixed fluid 100. The mixed fluid 100 is typically a fluid in which wet ozone gas and sulfuric acid droplets are mixed. This mixed fluid 100 is supplied from the first moving nozzle 9 to the upper surface of the substrate W.

Of course, an internal mixing type two-fluid nozzle that mixes fluids within the nozzle housing may also be used as the first moving nozzle 9.

The sulfuric acid tank 55 can be supplied with unused sulfuric acid (new liquid) by opening the new liquid valve 71A provided on the new liquid piping 71, or regenerated sulfuric acid can be supplied from the sulfuric acid recovery/regeneration unit 80. The sulfuric acid recovery/regeneration unit 80 recovers used sulfuric acid from the drainage piping 35 (recovery line) connected to the cup 29 corresponding to the guard 28 that receives the liquid discharged from the substrate W during processing with the mixed fluid in the processing cup 15 (see FIG. 2), and regenerates the sulfuric acid for reuse. For example, the sulfuric acid recovery/regeneration unit 80 can be configured to heat the recovered sulfuric acid and evaporate the water in the sulfuric acid to restore it to a target concentration.

Specifically, the sulfuric acid recovery/regeneration unit 80 includes a regeneration tank 81 that stores the sulfuric acid to be regenerated, a heater unit 82 that heats the sulfuric acid in the regeneration tank 81, and a regenerated sulfuric acid piping 83 that supplies the regenerated sulfuric acid from the regeneration tank 81 to the sulfuric acid tank 55. A regenerated sulfuric acid valve 83A, a pump 83B, and a filter 83C are arranged in the regenerated sulfuric acid piping 83. When the regenerated sulfuric acid valve 83A is opened, the regenerated sulfuric acid pumped out of the regeneration tank 81 by the pump 83B and from which foreign matter has been removed by the filter 83C is supplied to the sulfuric acid tank 55. In this way, the amount of sulfuric acid used can be reduced by regenerating and reusing the sulfuric acid.

In this example, a waste pipe 36 branches off from the drain pipe 35 (recovery line). By opening and closing a valve 37 provided on the drain pipe 35 between the branch point of the waste pipe 36 and the regeneration tank 81, and a valve 38 provided on the waste pipe 36, it is possible to select whether the liquid collected in the cup 29 is recovered for regeneration or discarded. For example, depending on the processing status on the substrate W, the liquid may be discarded when there is a large amount of foreign matter in the liquid, and recovered in the regeneration tank 81 when there is a small amount of foreign matter in the liquid.

FIG. 4 is a block diagram for explaining the electrical configuration of the substrate processing apparatus 1. The controller 3 is a computer including a computer main body 3a and a peripheral device 3d connected to the computer main body 3a. The computer main body 3a includes a processor (CPU) 3b that executes various commands and a memory 3c that stores information.

The peripheral device 3d includes an auxiliary storage device 3e that stores information such as programs, a reading device 3f that reads information from removable media (not shown), and a communication device 3g that communicates with other devices such as a host computer (not shown).

The controller 3 is connected to an input device 3A, a display device 3B, and an alarm device 3C. The input device 3A is operated when an operator such as a user or maintenance personnel inputs information to the substrate processing apparatus 1. The information is displayed on the screen of the display device 3B. The input device 3A may be any one 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 both as the input device 3A and the display device 3B. The alarm device 3C issues an alarm using one or more of light, sound, characters, and figures. If the input device 3A is a touch panel display, the input device 3A may also serve as the alarm device 3C.

The auxiliary storage device 3e is a non-volatile memory that retains memory even when power is not supplied. The auxiliary storage device 3e is, for example, a magnetic storage device such as a hard disk drive.

The auxiliary storage device 3e stores multiple recipes. A recipe is information that specifies the processing content, processing conditions, and processing procedure of the substrate W. The multiple recipes differ from each other in at least one of the processing content, processing conditions, and processing procedure of the substrate W.

The controller 3 controls each component of the substrate processing apparatus 1 so that the substrate W is processed according to a recipe specified by an external device such as a host computer.

　Controlled objects of the controller 3 include the first transport robot IR, the second transport robot CR, the rotation drive mechanism 23, the first nozzle drive mechanism 25, the second nozzle drive mechanism 26, the third nozzle drive mechanism 27, the heater drive mechanism 66, the power supply unit 63, the blower unit 31, the temperature sensor 62, the pumps 50D, 83B, the heater units 50E, 59, 82, the sulfuric acid valve 50A, the sulfuric acid flow rate control valve 50B, the common valve 51, the chemical solution valve 52A, the chemical solution flow rate control valve 52B, the rinse solution valve 53A, the rinse solution flow rate control valve 53B, the organic solvent valve 54A, the organic solvent flow rate control valve 54B, the ozone gas valve 70A, the ozone gas flow rate control valve 70B, the regenerated sulfuric acid valve 83A, and the valves 37, 38.

Although representative components are illustrated in FIG. 4, this does not mean that components not illustrated are not controlled by the controller 3, and the controller 3 can appropriately control each component provided in the substrate processing apparatus 1.

The following steps are performed by the controller 3 controlling the substrate processing apparatus 1. In other words, the controller 3 is programmed to perform the following steps.

FIG. 5 is a flow chart for explaining an example of substrate processing performed by the substrate processing apparatus 1. FIGS. 6A to 6C are schematic diagrams for explaining the state of the substrate W and its surroundings when the substrate processing is being performed. A resist film is formed on at least one of the pair of main surfaces of the substrate W used in the substrate processing. The resist film is typically an organic material film, and may be a resist film after being used as a mask for a pattern formation process (dry etching or wet etching), an ion implantation process, or the like.

In substrate processing by the substrate processing apparatus 1, for example, a substrate loading process (step S1), a substrate heating process (step S2), a nozzle arrangement process (step S3), a supply process (step S4; wet ozone gas supply process, sulfuric acid supply process), a mixed fluid supply process (step S5), a first rinsing process (step S6), a chemical supply process (step S7), a second rinsing process (step S8), an organic solvent supply process (step S9), a spin drying process (step S10), and a substrate removal process (step S11) are performed.

An unprocessed substrate W is carried into the processing unit 2 from the carrier C by the second transport robot CR (see FIG. 1) and handed over to the spin chuck 8 (substrate carrying process: step S1). As a result, the substrate W is held horizontally by the spin chuck 8 (substrate holding process). At this time, the substrate W is held by the spin chuck 8 so that the main surface on which the resist film is formed faces up. Before processing, the main surface of the substrate W (the main surface on which the resist film is formed) is a dry surface with no liquid film present. The substrate W continues to be held by the spin chuck 8 until the spin dry process (step S10) is completed.

With the substrate W held by the spin chuck 8, the rotation drive mechanism 23 starts rotating the substrate W (substrate rotation process). During substrate processing, an airflow from above to below is constantly formed in the internal space 7c of the chamber 7, and the airflow passes through the inside of the processing cup 15 and flows into the exhaust pipe 32.

After the second transport robot CR retreats from the chamber 7, a substrate heating step (step S2) is performed to heat the substrate W. Specifically, the current supply unit 63 supplies current to the heater 61, and the temperature of the heater 61 begins to rise. Then, the heater drive mechanism 66 moves the substrate heating member 14 from the retreated position to the proximal position. As shown in FIG. 6A, the temperature of the heater 61 begins to rise, and the substrate heating member 14 is positioned in the proximal position, thereby beginning heating of the substrate W (substrate heating start step: step S21).

Meanwhile, a nozzle arrangement process (step S3) is performed in which the first nozzle drive mechanism 25 moves the first moving nozzle 9 to a processing position. The processing position is a position where the first moving nozzle 9 faces the main surface of the substrate W (the main surface on which the resist film is formed) and can supply the mixed fluid 100 to the main surface of the substrate W.

When the temperature detected by the temperature sensor 62 reaches the processing temperature range, the ozone gas valve 70A and the sulfuric acid valve 50A are opened with the first moving nozzle 9 positioned at the processing position, thereby starting the supply of wet ozone gas and sulfuric acid to the first moving nozzle 9 (wet ozone gas supply start step: step S41; sulfuric acid supply start step: S42). As a result, as shown in FIG. 6B, a mixed fluid 100 of wet ozone gas and sulfuric acid is discharged from the first moving nozzle 9, and the supply of the mixed fluid 100 to the upper surface of the substrate W is started (mixed fluid supply start step: step S51). Meanwhile, the first nozzle driving mechanism 25 moves the first moving nozzle 9 to move the landing point of the mixed fluid on the upper surface of the substrate W in the radial direction of the substrate W (scan step: step S52). Since the substrate W is rotating around the rotation axis A1, the mixed fluid 100 discharged from the first moving nozzle 9 scans the entire upper surface of the substrate W.

After the supply of the mixed fluid 100 has started, when a predetermined time has elapsed, the ozone gas valve 70A and the sulfuric acid valve 50A are closed, and the supply of wet ozone gas and sulfuric acid to the first moving nozzle 9 is stopped (wet ozone gas supply stopping step: step S43; sulfuric acid supply stopping step: S44). This stops the supply of the mixed fluid 100 to the upper surface of the substrate W (mixed fluid supply stopping step: step S53).

After the ejection of the mixed fluid 100 has stopped, the first nozzle driving mechanism 25 retracts the first moving nozzle 9 (step S54). Meanwhile, the heater driving mechanism 66 moves the substrate heating member 14 from the close position to the retracted position. By placing the substrate heating member 14 in the retracted position (the position shown in FIG. 6C), the heating of the substrate W is stopped (substrate heating stopping step: step S22). This ends the substrate heating step (step S2).

By scanning the upper surface of the substrate W with a mixed fluid 100 of wet ozone gas and sulfuric acid, the mixed fluid 100 can be supplied to the entire upper surface of the substrate W. The action of this mixed fluid 100 breaks down the resist on the main surface of the substrate W, and the resist film is removed (peeled off) from the main surface of the substrate W. Then, the liquid components (mainly sulfuric acid) in the mixed fluid 100 flow outward along the upper surface of the substrate W in the direction of the rotation radius due to the centrifugal force associated with the rotation of the substrate W, thereby removing at least a portion of the resist film peeled off from the main surface of the substrate W outside the substrate W.

In the first moving nozzle 9, the sulfuric acid and the water vapor in the wet ozone gas come into contact with each other, generating heat of dilution, and the ozone in the wet ozone gas decomposes at the interface of the sulfuric acid heated by the heat of dilution. This generates Caro's acid (peroxomonosulfuric acid). By supplying the mixed fluid 100 containing this Caro's acid (particularly active oxygen) to the upper surface of the substrate W, the resist is decomposed, and the resist film can be efficiently removed (peeled off) from the main surface of the substrate W. Moreover, since the sulfuric acid and the water vapor come into contact with each other just before being supplied to the substrate W, the heat of dilution can be efficiently used to decompose the ozone gas and generate Caro's acid, and the Caro's acid immediately after generation can be supplied to the main surface of the substrate W. Moreover, the Caro's acid is heated by the heat of dilution, and the Caro's acid is supplied to the main surface of the substrate W at a higher temperature than the sulfuric acid before mixing. In this way, the resist can be efficiently decomposed by the high-temperature Caro's acid immediately after generation. Furthermore, in this embodiment, the substrate heating process (step S2) is performed in parallel, so that the resist film can be removed even more efficiently.

After the substrate heating process (step S2) and the mixed fluid supply process (step S5), a first rinsing process (step S6) is performed to clean the top surface of the substrate W by supplying a top surface rinsing liquid for the substrate W.

Specifically, the second nozzle driving mechanism 26 moves the second moving nozzle 10 to the processing position. The processing position is, for example, the central position. With the second moving nozzle 10 positioned at the processing position, the common valve 51 and the rinsing liquid valve 53A are opened. As a result, as shown in FIG. 6C, rinsing liquid is ejected from the second moving nozzle 10, and the supply of rinsing liquid to the upper surface of the substrate W begins (rinsing liquid supply start process, rinsing liquid supply process). The rinsing liquid that has landed on the upper surface of the substrate W moves toward the peripheral portion of the upper surface of the substrate W, and the rinsing liquid spreads over the entire upper surface of the substrate W.

After the supply of rinsing liquid has started and a predetermined time has elapsed, the common valve 51 and the rinsing liquid valve 53A are closed. This stops the supply of rinsing liquid to the upper surface of the substrate W (rinsing liquid supply stopping process). This ends the first rinsing process. The first rinsing process drains sulfuric acid from the upper surface of the substrate W. The resist film that has been peeled off from the upper surface of the substrate W is washed away together with the sulfuric acid and is removed from the upper surface of the substrate W to the outside of the substrate W.

After the supply of rinsing liquid to the upper surface of the substrate W is stopped, a chemical liquid supplying process (step S7) is performed to supply a chemical liquid to the upper surface of the substrate W. Specifically, the common valve 51 and the chemical liquid valve 52A are opened while the second moving nozzle 10 is positioned at the processing position. This stops the ejection of the rinsing liquid, and furthermore, a continuous flow of chemical liquid is ejected (supplied) from the second moving nozzle 10 toward the upper surface of the substrate W (chemical liquid ejecting process, chemical liquid supplying process). This causes the upper surface of the substrate W to be treated with the chemical liquid. This removes any residue remaining on the upper surface of the substrate W.

After the chemical supply process (step S7), a second rinse process (step S8) is performed in which a rinse liquid is supplied to the upper surface of the substrate W to clean the upper surface of the substrate W. Specifically, while the second moving nozzle 10 faces the upper surface of the substrate W and the common valve 51 is maintained in an open state, the chemical valve 52A is closed and the rinse liquid valve 53A is opened. This stops the discharge of the chemical liquid from the second moving nozzle 10, and furthermore, a continuous flow of the rinse liquid is discharged (supplied) from the second moving nozzle 10 toward the upper surface of the substrate W (rinsing liquid discharge process, rinsing liquid supply process). This causes the chemical liquid on the upper surface of the substrate W to be discharged outside the substrate W together with the rinse liquid, and the upper surface of the substrate W is cleaned.

After the second rinsing step (step S8), an organic solvent supplying step (step S9) is performed to supply organic solvent to the upper surface of the substrate W. Specifically, the ejection of rinsing liquid from the second moving nozzle 10 is stopped, and the second moving nozzle 10 is retracted. Then, the third nozzle driving mechanism 27 positions the third moving nozzle 11 facing the upper surface of the substrate W, and the organic solvent valve 54A is opened. As a result, a continuous flow of organic solvent is ejected (supplied) from the third moving nozzle 11 toward the upper surface of the substrate W (organic solvent ejecting step, organic solvent supplying step). As a result, the rinsing liquid on the upper surface of the substrate W is replaced with the organic solvent.

The organic solvent used in substrate processing is preferably more volatile than the rinse liquid. If so, then by replacing the rinse liquid with the organic solvent, the substrate W can be dried well in the subsequent spin drying process (step S10). The organic solvent used in substrate processing is preferably lower in surface tension than the rinse liquid. If so, then in the case where an uneven pattern is formed on the top surface of the substrate W, the surface tension acting on the uneven pattern when the top surface of the substrate W is dried can be reduced, and collapse of the uneven pattern can be suppressed.

Next, a spin-dry process (step S10) is performed in which the substrate W is rotated at high speed to dry the upper surface of the substrate W. Specifically, the organic solvent valve 54A is closed to stop the supply of organic solvent to the upper surface of the substrate W. Then, the rotation drive mechanism 23 accelerates the rotation of the substrate W, causing the substrate W to rotate at high speed (for example, 1500 rpm). As a result, a large centrifugal force acts on the rinsing liquid adhering to the substrate W, and the organic solvent is shaken off around the substrate W.

After the spin dry process (step S10), the rotation drive mechanism 23 stops the rotation of the substrate W. Then, the second transport robot CR enters the processing unit 2, receives the processed substrate W from the spin chuck 8, and removes it from the processing unit 2 (substrate removal process: step S11). The substrate W is passed from the second transport robot CR to the first transport robot IR, which stores it in the carrier C.

7 shows an example of the scanning process (step S52 in FIG. 5). In this example, the initial position of the first moving nozzle 9 when starting to discharge the mixed fluid 100 is a position where the landing point 100a of the mixed fluid 100 is located on the outer periphery of the substrate W. When the supply of the mixed fluid 100 starts, the first moving nozzle 9 starts to move, so that the landing point 100a of the mixed fluid 100 moves from the outer periphery of the substrate W toward the center of rotation (axis of rotation A1). Thereafter, if necessary, the first moving nozzle 9 may be moved so that the landing point of the mixed fluid 100 repeatedly moves back and forth between the outer periphery of the substrate W and the center of rotation (axis of rotation A1). In FIG. 7, the scanning range is shown to be approximately the radius of the substrate W, but the scanning range may be approximately the diameter of the substrate W.

The initial landing point of the mixed fluid 100 is set on the outer periphery of the substrate W, and as the landing point 100a moves toward the center of rotation (rotation axis A1), the mixed fluid 100 lands on a liquid film-free (substantially dry) surface on the substrate W. As a result, the Caro's acid in the mixed fluid 100 acts on the resist film without being diluted, allowing the resist decomposition reaction to occur efficiently. This enables highly efficient resist removal.

As described above, according to this embodiment, a mixed fluid 100 of water vapor, ozone gas, and sulfuric acid is supplied to the main surface of the substrate W, and the mixed fluid 100 removes the resist film from the main surface of the substrate W. Heat of dilution is generated when the sulfuric acid comes into contact with the water vapor, and the ozone is decomposed at the interface of the sulfuric acid heated by the heat of dilution to generate Caro's acid (peroxomonosulfuric acid). The action of this Caro's acid (particularly active oxygen) decomposes the resist, and the resist film can be efficiently removed (peeled off) from the main surface of the substrate W.

The resist removal process using the mixed fluid 100 does not require (use) costly hydrogen peroxide water, making it possible to realize a resist removal process that is inexpensive and has high stripping performance. Furthermore, the sulfuric acid in the mixed fluid 100 flows down from the substrate W as liquid, so it can be recovered and reused. And because the amount of water in the sulfuric acid that flows down from the substrate W is small, the technical and cost barriers to regenerating the recovered sulfuric acid to the target concentration are not high. Therefore, because sulfuric acid is easy to reuse, the amount of sulfuric acid used can be reduced. In this way, the resist film on the substrate W can be efficiently removed while reducing the amount of chemical used.

In this embodiment, ozone gas is bubbled in water to generate wet ozone gas in which water vapor and ozone gas are mixed in advance. Therefore, wet ozone gas and sulfuric acid can be mixed in the first moving nozzle 9 consisting of a two-fluid nozzle to generate a mixed fluid 100. When wet ozone gas and sulfuric acid come into contact with each other in the first moving nozzle 9 (two-fluid nozzle), heat of dilution is generated by the moisture (water vapor) in the wet ozone gas, and ozone can be brought into contact with the interface of the sulfuric acid heated by the heat of dilution. Therefore, Caro's acid can be efficiently generated, and the Caro's acid immediately after generation can be supplied to the main surface of the substrate to react with the resist film. This allows efficient resist removal processing to be achieved. Generating wet ozone gas by bubbling ozone gas in water is a relatively simple method, and has the advantage of being able to mix three fluids, namely water vapor, ozone gas, and sulfuric acid, using a two-fluid nozzle.

By heating the sulfuric acid in advance (for example, to 120°C to 190°C) and by heating the water through which the ozone gas is to be bubbled, when the wet ozone gas comes into contact with the sulfuric acid, the interface of the sulfuric acid will definitely exceed the decomposition temperature of ozone (about 130°C). This makes it possible to efficiently produce Caro's acid, which contains a large amount of active oxygen (oxygen radicals). When wet ozone gas is produced by bubbling in water, strict temperature control is not required to avoid the decomposition of the ozone gas, since the boiling point of water is lower than the decomposition temperature of ozone gas.

In addition, in this embodiment, wet ozone gas can be generated and pumped by supplying ozone gas into the water in the sealed container 57 that forms a closed space and bubbling it. This allows fluid mixing in the first moving nozzle 9 (multiple fluid nozzle) with a simple configuration. By heating the water in the sealed container 57, it is possible to promote the generation of water vapor by bubbling, so that wet ozone gas containing a moderate amount of water vapor can be generated and pumped to the first moving nozzle 9.

In addition, in this embodiment, at least immediately after the supply of the mixed fluid 100 begins, the main surface of the substrate W presents a dry surface free of any liquid film. Therefore, when the mixed fluid 100 is supplied, the Caro's acid in the mixed fluid 100 acts on the resist film without being diluted. Therefore, the resist decomposition reaction by the Caro's acid occurs efficiently, making it possible to remove the resist with high efficiency.

In particular, in this embodiment, in the scanning step (step S52 in FIG. 5) in which the first moving nozzle 9 is scanned while rotating the substrate W around the rotation axis A1, the landing point 100a of the mixed fluid 100 is moved from the outer periphery of the substrate W toward the rotation axis A1 while the mixed fluid 100 is discharged from the first moving nozzle 9. As the substrate W rotates, the liquid on the main surface of the substrate W flows toward the outer periphery due to centrifugal force. Therefore, by starting the scanning of the substrate main surface with the mixed fluid 100 discharged from the first moving nozzle 9, which is a multiple-fluid nozzle, from the outer periphery of the substrate W, the mixed fluid 100 is supplied to a dry surface that is substantially free of a liquid film. As a result, the Caro's acid in the mixed fluid 100 acts on the resist film on the substrate main surface without being diluted, thereby achieving highly efficient resist removal.

In addition, in this embodiment, the resist film on the main surface of the substrate W can be removed without contacting the sulfuric acid with hydrogen peroxide. Since the hydrogen peroxide does not come into contact with the sulfuric acid, it is possible to avoid mixing a large amount of moisture into the sulfuric acid. This reduces the process for removing the moisture in the sulfuric acid, making it easier to regenerate and reuse the sulfuric acid, and therefore reducing the amount of sulfuric acid used.

FIG. 8 is a diagram for explaining the configuration of another embodiment of the present invention. In this embodiment, a three-fluid nozzle is used as the first moving nozzle 9. The first moving nozzle 9 consisting of a three-fluid nozzle is supplied with sulfuric acid (preferably heated sulfuric acid) from a sulfuric acid supply unit 16, ozone gas from an ozone gas supply unit 13A, and water vapor from a water vapor supply unit 13B. The ozone gas supply unit 13A and the water vapor supply unit 13B are preferably configured to pressure-feed the ozone gas and water vapor, respectively, to the first moving nozzle 9.

The three-fluid nozzle constituting the first moving nozzle 9 is configured to mix sulfuric acid, ozone gas, and water vapor to generate a mixed fluid 100, and to eject the mixed fluid 100 toward the main surface of the substrate W. In this example, the ozone gas and water vapor are mixed (internal mixing) in the second passage 92 of the nozzle housing 90 and ejected from the second outlet 92a. Meanwhile, the sulfuric acid passes through the first passage 91 in the nozzle housing 90 and is ejected from the first outlet 91a. Then, the sulfuric acid and the mixed gas of ozone gas and water vapor collide and mix (external mixing) outside the nozzle housing 90 near the outlets 91a, 92a, thereby forming the mixed fluid 100.

Of course, this configuration is just one example, and a three-fluid nozzle may be used in which three separate flow paths for sulfuric acid, ozone gas, and water vapor are formed in the nozzle housing, and the sulfuric acid, ozone gas, and water vapor come into contact with each other and are mixed inside or outside the nozzle housing.

The water vapor supply unit 13B preferably supplies heated water vapor to the first moving nozzle 9. For example, the water vapor supply unit 13B preferably supplies water vapor that is higher than room temperature and not higher than 100°C (for example, about 80°C) to the first moving nozzle 9. This prevents ozone from being decomposed when the water vapor comes into contact with ozone gas, and allows high-temperature Caro's acid to be generated when the water vapor and ozone come into contact with sulfuric acid.

This invention is not limited to the embodiments described above, but can be embodied in other forms, as listed below as examples.

In each of the above-described embodiments, the processing liquid is configured to be ejected from multiple movable nozzles. However, unlike the above-described embodiments, the processing liquid may be ejected from a fixed nozzle whose position in the horizontal direction is fixed, or all processing liquid may be ejected from a single nozzle.

In the above-described embodiment, the sulfuric acid is heated by the heater unit 50E disposed in the sulfuric acid piping 40. However, the sulfuric acid may be heated in the sulfuric acid tank 55. Also, a circulation pipe for circulating the sulfuric acid in the sulfuric acid tank 55 may be provided, and a heater unit may be disposed in the circulation pipe to heat the sulfuric acid.

The heating of the substrate W is not limited to heating by the substrate heating member 14. Specifically, the substrate heating member may include an infrared lamp facing the upper surface of the substrate W, or may include a heater facing the upper surface of the substrate W. Alternatively, the substrate heating member may include a heating fluid nozzle that supplies a heating fluid such as nitrogen gas or hot water to the lower surface of the substrate W. The substrate heating member may be configured to heat the plate body 60 by circulating a heating fluid within the plate body 60. When a heating fluid is used, the temperature of the substrate W is adjusted by adjusting the opening of a valve that controls the flow rate of the heating fluid. The substrate heating member 14 is not an essential component of this invention, and the substrate heating member 14 and the substrate heating process (step S2) may be omitted.

The substrate processing apparatus 1 may be provided with a cooling plate (not shown) for cooling the substrate W. After the substrate heating stopping step (step S22), the substrate W may be cooled to room temperature by the cooling plate.

In each of the above-described embodiments, the spin chuck 8 is a gripping-type spin chuck that grips the periphery of the substrate W with a plurality of gripping pins 20, but the spin chuck 8 is not limited to a gripping-type spin chuck. For example, the spin chuck 8 may be a vacuum suction-type spin chuck that adsorbs the substrate W to the spin base 21.

In each of the above-described embodiments, the controller 3 controls the entire substrate processing apparatus 1. However, the controllers that control each component of the substrate processing apparatus 1 may be distributed to multiple locations. Furthermore, the controller 3 does not need to directly control each component, and the signal output from the controller 3 may be received by a slave controller that controls each component of the substrate processing apparatus 1.

In the above-described embodiment, the substrate processing apparatus 1 includes a transport robot (first transport robot IR and second transport robot CR), multiple processing units 2, and a controller 3. However, the substrate processing apparatus 1 may be configured with a single processing unit 2 and controller 3 and may not include a transport robot. Alternatively, the substrate processing apparatus 1 may be configured with only a single processing unit 2. In other words, the processing unit 2 may be an example of a substrate processing apparatus.

Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical content of the present invention, and the present invention should not be interpreted as being limited to these examples, and the scope of the present invention is limited only by the scope of the attached claims.

1: Substrate processing apparatus 2: Processing unit 3: Controller 7: Chamber 8: Spin chuck 9: First moving nozzle 10: Second moving nozzle 11: Third moving nozzle 13: Water vapor/ozone supply unit 13A: Ozone gas supply unit 13B: Water vapor supply unit 15: Processing cup 16: Sulfuric acid supply unit 23: Rotation drive mechanism 28: Guard 29: Cup 35: Drainage pipe 40: Sulfuric acid pipe 45: Wet ozone gas pipe 50A: Sulfuric acid valve 50B: Sulfuric acid flow rate control valve 50C: Filter 50D: Pump 50E: Heater unit 55: Sulfuric acid tank 56: Wet ozone gas generation unit 57: Sealed container 58: Ozone gas supply unit 59: Heater unit 70: Ozone gas pipe 70A: Ozone gas valve 70B: Ozone gas flow rate control valve 70C: Filter 71 : New liquid piping 71A : New liquid valve 80 : Sulfuric acid recovery/regeneration unit 81 : Regeneration tank 82 : Heater unit 83 : Regenerated sulfuric acid piping 83A : Regenerated sulfuric acid valve 83B : Pump 83C : Filter 90 : Nozzle housing 91 : First passage 91a : First discharge port 92 : Second passage 92a : Second discharge port 100 : Mixed fluid 100a : Landing point A1 : Rotation axis

Claims (14)

1. A method for treating a substrate having a resist film formed on a main surface thereof, comprising the steps of:
   a nozzle arrangement step of arranging a multi-fluid nozzle toward a main surface of the substrate;
   a supply step of supplying water vapor, ozone gas, and sulfuric acid to the multiple fluid nozzle;
   a mixed fluid supplying step of supplying a mixed fluid of water vapor, ozone gas, and sulfuric acid from the multiple fluid nozzle toward the main surface of the substrate to remove the resist film from the main surface of the substrate;
   A method for processing a substrate, comprising:
2. The substrate processing method according to claim 1, wherein the supplying step includes a wet ozone gas supplying step of supplying wet ozone gas, which is a mixture of water vapor and ozone gas, to the multiple fluid nozzle.
3. The substrate processing method according to claim 2, wherein the wet ozone gas supply process includes a wet ozone gas generation process in which ozone gas is bubbled in water to generate wet ozone gas.
4. The substrate processing method according to claim 2, wherein the wet ozone gas supplying step includes a step of bubbling ozone gas supplied from an ozone gas supply source in water in a closed space to generate wet ozone gas in the closed space, and pressure-feeding the wet ozone gas from the closed space to the multiple fluid nozzle.
5. The substrate processing method according to any one of claims 1 to 4, wherein the mixed fluid supplying step supplies the mixed fluid containing Caro's acid produced by mixing the ozone gas and the sulfuric acid toward the main surface of the substrate.
6. The substrate processing method according to claim 5, wherein the mixed fluid supply step supplies the mixed fluid containing the Caro's acid, which is hotter than the sulfuric acid, toward the main surface of the substrate by heat of dilution generated by contact between the water vapor and the sulfuric acid.
7. The substrate processing method according to any one of claims 1 to 6, wherein the water vapor supplied to the multiple fluid nozzle is at or below 100°C.
8. The substrate processing method according to any one of claims 1 to 7, wherein the main surface of the substrate is a dry surface without a liquid film before the mixed fluid is supplied in the mixed fluid supplying step.
9. The method further includes a substrate rotation step of rotating the substrate about a rotation axis passing through the main surface,
   9. The substrate processing method according to claim 1, wherein the mixed fluid supplying step is performed in parallel with the substrate rotating step, and includes a scanning step of moving a landing point of the mixed fluid on the main surface from an outer circumferential edge of the substrate toward the rotation axis while discharging the mixed fluid from the multiple-fluid nozzle.
10. The substrate processing method according to any one of claims 1 to 9, wherein the resist film on the main surface of the substrate is removed without contacting the sulfuric acid with hydrogen peroxide.
11. a substrate holding unit for holding a substrate;
    a multi-fluid nozzle arranged to face a main surface of a substrate held by the substrate holding unit;
    a water vapor/ozone supply unit for supplying water vapor and ozone gas to the multiple fluid nozzle;
    a sulfuric acid supply unit for supplying sulfuric acid to the multiple fluid nozzle;
    a substrate processing apparatus configured to supply a mixed fluid of water vapor, ozone gas, and sulfuric acid from the multiple fluid nozzle toward a main surface of a substrate held by the substrate holding unit.
12. The substrate processing apparatus of claim 11, wherein the water vapor/ozone supply unit supplies wet ozone gas, which is a mixed gas of water vapor and ozone gas.
13. The substrate processing apparatus of claim 12, wherein the water vapor/ozone supply unit includes a wet ozone gas generation unit that generates the wet ozone gas by bubbling ozone gas in water.
14. The substrate processing apparatus according to claim 13, wherein the wet ozone gas generating unit includes a sealed container that forms a closed space, and an ozone gas supply unit that supplies ozone gas into the water stored in the sealed container, and pressure-feeds the wet ozone gas toward the multiple fluid nozzle.

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