Substrate processing method and substrate processing device

Abstract

The present invention relates to a substrate processing method and a substrate processing apparatus. The substrate processing method for removing a resist having a hardened layer from a substrate surface comprises a hardened layer removal step and a wet treatment step. The hardened layer removal step includes a heating step of heating the substrate to a temperature of 150°C or higher, and an ozone gas supply step of supplying ozone gas to the surface of the substrate heated in the heating step, thereby generating oxygen radicals near the substrate surface and removing the hardened layer. The wet treatment step involves supplying a treatment solution containing sulfuric acid to the substrate surface after the hardened layer removal step to remove the resist from the substrate surface.

Description

[0001] Related applications

[0002] This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2020-146099, filed on August 31, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a method and apparatus for processing substrates. The substrates to be processed include, for example, semiconductor wafers, FPD (Flat Panel Display) substrates such as liquid crystal displays and organic EL (electroluminescence) displays, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and solar cell substrates. Background Art

[0004] The manufacturing process for semiconductor devices includes irradiating a semiconductor substrate (typically a silicon wafer) with ions. For example, this corresponds to an ion implantation step for introducing impurity ions into the semiconductor substrate, or an ion etching step for forming a pattern. In this step, a resist pattern is formed on the surface of the semiconductor substrate, and the semiconductor substrate is irradiated with ions using the resist as a mask. This allows for selective ion irradiation of the semiconductor substrate.

[0005] Ions are also irradiated onto the resist used as a mask. This causes the surface of the resist to carbonize and deteriorate, forming a hardened layer. In particular, a strong hardened layer forms on the surface of the resist that has been injected with a high dose of ions.

[0006] One treatment for removing a resist having a hardened layer from a substrate surface is a high-temperature SPM treatment in which a high-temperature sulfuric acid / hydrogen peroxide mixture (SPM) is supplied to the substrate surface (see Japanese Patent Application Laid-Open No. 2016-181677). Summary of the Invention

[0007] However, since the hardened layer cannot be easily removed, SPM treatment requires a long, high-temperature process. Consequently, SPM consumption increases. In particular, sulfuric acid, the liquid that constitutes SPM, carries a significant environmental burden, and even neutralization requires significant costs, so reducing its usage is desirable. Furthermore, since prolonged treatment hinders productivity improvements, shortening the treatment time is desirable.

[0008] Therefore, one embodiment of the present invention provides a substrate processing method and a substrate processing apparatus that can reduce the amount of processing liquid containing sulfuric acid used and remove a resist having a hardened layer from a substrate. Furthermore, one embodiment of the present invention provides a substrate processing method and a substrate processing apparatus that can remove a resist having a hardened layer from a substrate in a short processing time.

[0009] One embodiment of the present invention provides a substrate processing method for removing a resist having a hardened layer from a substrate surface. The method includes: a hardened layer removal step (ozone treatment step), comprising a heating step of heating the substrate to a temperature of 150°C or higher, and an ozone gas supply step of supplying ozone gas to the surface of the substrate heated in the heating step, thereby generating oxygen radicals near the substrate surface to remove the hardened layer; and a wet treatment step of supplying a treatment solution containing sulfuric acid to the substrate surface after the hardened layer removal step to remove the resist from the substrate surface.

[0010] According to the method, ozone gas is supplied to the surface of a substrate heated to above 150°C. The ozone gas receives heat from the substrate surface and thermally decomposes, thereby generating oxygen free radicals. The oxygen free radicals act on the hardened layer, thereby removing the hardened layer. Subsequently, if a wet treatment step is performed in which a treatment liquid containing sulfuric acid is supplied to the substrate surface, the treatment liquid quickly reaches the non-hardened layer of the resist and dissolves the non-hardened layer. Therefore, the resist can be removed by wet treatment in a short time. As a result, the consumption of the treatment liquid containing sulfuric acid can be reduced. In addition, since the resist can be removed by wet treatment in a short time, the processing time can be shortened, which helps to improve productivity.

[0011] In the hardened layer removal step, which is performed by heating the substrate and supplying ozone gas, a portion of the hardened layer can be removed, or the entire hardened layer can be removed. Even if a portion of the hardened layer remains at the beginning of the wet treatment, the time it takes for the treatment liquid containing sulfuric acid to reach the non-hardened layer of the resist and the amount of treatment liquid consumed are shorter than in the case where the hardened layer removal step is performed without supplying ozone gas to the heated substrate. In the hardened layer removal step, it is preferred to remove at least the hardened layer until a path for the treatment liquid to penetrate the hardened layer and reach the non-hardened layer is formed. Thus, during the wet treatment, the treatment liquid containing sulfuric acid quickly reaches the non-hardened layer, so even if a portion of the hardened layer remains, it can be peeled off together with the non-hardened layer.

[0012] In order to avoid cracking of the resist due to heating of the substrate, the temperature of the substrate in the heating step is preferably set to 170° C. or lower.

[0013] In one embodiment of the present invention, the heating step is performed by placing the substrate on a hot plate disposed within a heat treatment chamber (preferably a sealed chamber). Furthermore, the ozone gas supplying step is performed by introducing ozone gas into the heat treatment chamber. Furthermore, after stopping the ozone gas supplying step and completing the hardened layer removal step, the substrate processing method further includes a high-temperature inert gas supplying step of introducing an inert gas having a temperature of 150°C or higher into the heat treatment chamber.

[0014] According to the method, a substrate is placed on a hot plate within a heat treatment chamber and heated to a temperature of 150°C or higher. Ozone gas is then introduced into the heat treatment chamber, where it reaches the substrate surface and decomposes due to heat from the substrate. After the ozone gas supply is stopped and the hardened layer removal step is completed, an inert gas at a temperature of 150°C or higher is introduced into the heat treatment chamber.

[0015] Since the temperature of the ozone gas does not reach 150°C at a position in the heat treatment chamber away from the hot plate and the substrate, thermal decomposition of the ozone gas does not occur here. Since ozone is harmful, it is necessary to exhaust the ozone from the heat treatment chamber before opening the heat treatment chamber to remove the substrate. However, it takes a considerable amount of time to replace the atmosphere in the heat treatment chamber until the ozone concentration in the heat treatment chamber becomes below the allowable value. Therefore, in this embodiment, a high-temperature inert gas above 150°C is introduced into the heat treatment chamber. As a result, the ozone remaining in the heat treatment chamber is rapidly thermally decomposed. Although oxygen free radicals are generated by thermal decomposition, since their lifespan is short, the ozone in the heat treatment chamber can be eliminated in a short time. In this way, since the time between the hardening layer removal step and the wet treatment step can be shortened, productivity can be further improved.

[0016] In one embodiment of the present invention, the substrate processing method further includes, after the high-temperature inert gas supplying step, a room-temperature inert gas supplying step of introducing a room-temperature inert gas into the heat treatment chamber.

[0017] Since the heat treatment chamber reaches a high temperature due to substrate heating and the supply of high-temperature inert gas, the chamber can be rapidly cooled by subsequently supplying room-temperature inert gas to replace the internal atmosphere. This shortens the time until the substrate is removed from the heat treatment chamber. Since ozone in the heat treatment chamber is eliminated by thermal decomposition caused by the supply of high-temperature inert gas, the prolonged supply of room-temperature inert gas is unnecessary.

[0018] Room temperature refers to the ambient temperature in which the substrate processing method is performed, and is typically the temperature in the factory in which the substrate processing method is performed. Specifically, the inert gas at room temperature is an inert gas supplied from an inert gas supply source without being heated.

[0019] In one embodiment of the present invention, the ozone gas supplying step supplies ozone gas having a temperature lower than 150° C. to the surface of the substrate.

[0020] By supplying ozone gas at a temperature below 150°C, it reaches the substrate surface in an undecomposed state. Consequently, the heat from the substrate causes thermal decomposition of ozone near the substrate surface, generating oxygen radicals. This ensures that the oxygen radicals act reliably on the hardened resist layer, enabling efficient processing.

[0021] One embodiment of the present invention provides a substrate processing device, comprising: a substrate heating unit, having a heat treatment chamber for accommodating a substrate, capable of heating the substrate to above 150° C. in the heat treatment chamber; an ozone gas supply unit, supplying ozone gas into the heat treatment chamber; and a processing liquid supply unit, supplying a processing liquid containing sulfuric acid to the substrate.

[0022] With this configuration, the aforementioned substrate processing method can be implemented. Specifically, the substrate can be heated to above 150°C in a heat treatment chamber, and ozone gas can be supplied to the heated substrate surface. This thermal decomposition of the ozone on the substrate surface generates oxygen radicals, which can remove the hardened resist layer. Consequently, subsequent treatment with a treatment solution containing sulfuric acid can achieve resist removal in a shorter time, thereby reducing consumption of the treatment solution containing sulfuric acid and improving productivity.

[0023] In one embodiment of the present invention, the substrate processing apparatus further includes a high-temperature inert gas supply unit for supplying an inert gas at a temperature of 150° C. or higher into the heat treatment chamber.

[0024] With this configuration, ozone can be supplied into the heat treatment chamber while the substrate is heated. After removing the hardened resist layer, an inert gas at a temperature of 150°C or higher can be supplied into the heat treatment chamber. This allows for thermal decomposition of any remaining undecomposed ozone within the heat treatment chamber. This allows for rapid reduction of ozone levels within the heat treatment chamber, shortening the time required to remove the processed substrate from the heat treatment chamber and improving productivity.

[0025] In one embodiment of the present invention, the substrate processing apparatus further includes a room temperature inert gas supply unit for supplying room temperature inert gas into the heat treatment chamber.

[0026] According to the above configuration, the atmosphere in the heat treatment chamber can be replaced with an inert gas at room temperature, thereby accelerating the cooling of the heat treatment chamber and shortening the time until the substrate is removed from the heat treatment chamber, thereby improving productivity.

[0027] In one embodiment of the present invention, the ozone gas supply unit supplies ozone gas having a temperature lower than 150° C. into the heat treatment chamber.

[0028] This configuration allows ozone gas to reach the substrate surface in an undecomposed state. Since the lifetime of oxygen radicals generated by thermal decomposition of ozone is short, it is desirable to thermally decompose ozone near the substrate surface in order to allow the oxygen radicals to act on the hardened resist layer. Therefore, by supplying ozone gas at a temperature below 150°C, thermal decomposition can occur near the substrate surface, allowing the generated oxygen radicals to act on the hardened resist layer.

[0029] In one embodiment of the present invention, the substrate heating unit includes a hot plate on which the substrate is placed. Heating the hot plate allows the substrate to be heated without heating the entire heat treatment chamber. This allows for efficient thermal decomposition of ozone on the substrate surface.

[0030] In one embodiment of the present invention, the treatment liquid supply unit is configured to supply a treatment liquid containing sulfuric acid to the substrate within a liquid treatment chamber separate from the heat treatment chamber. This allows for efficient substrate treatment by performing dry treatment (hardened layer removal) and wet treatment in separate chambers. This eliminates the need to clean the chamber environment after dry treatment for wet treatment, or vice versa.

[0031] The above and other further objects, features and effects of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a plan view schematically showing the structure of a substrate processing apparatus according to one embodiment of the present invention.

[0033] Figure 2 This is a schematic cross-sectional view for explaining a configuration example of a dry processing unit provided in the substrate processing apparatus.

[0034] Figure 3 It is a system diagram for explaining a configuration example of a gas supply system and an exhaust system for the heat treatment unit.

[0035] Figure 4 This is a schematic cross-sectional view for explaining a configuration example of a wet processing unit provided in the substrate processing apparatus.

[0036] Figure 5 This is a block diagram for explaining a configuration example related to control of the substrate processing apparatus.

[0037] Figures 6A to 6C A typical example of substrate processing performed by the substrate processing apparatus is shown.

[0038] Figure 7 This is a diagram used to illustrate the thermal decomposition of ozone gas.

[0039] Figure 8A and Figure 8B This is a flowchart for explaining a specific substrate processing flow of the substrate processing apparatus.

[0040] Figure 9A and Figure 9B These are diagrams for explaining the effects of resist stripping treatments by ozone treatment and high-temperature SPM treatment.

[0041] Figure 10A and Figure 10B Represents the results of experiments investigating the effects of treatments on substrates. DETAILED DESCRIPTION

[0042] Figure 1 This is a top view schematically illustrating the configuration of a substrate processing apparatus according to one embodiment of the present invention. The substrate processing apparatus 1 is a single-wafer apparatus that processes substrates W one by one. Substrates W are, for example, semiconductor wafers. The substrate processing apparatus 1 includes a plurality of load ports LP, each holding a plurality of carriers C that hold substrates W, and a plurality of processing units 2 that process the substrates W transferred from the load ports LP using a processing fluid such as a processing liquid or a processing gas.

[0043] The substrate processing apparatus 1 further includes a transport unit (IR, SH, CR) for transporting substrates W, and a control unit (controller) 3 for controlling the substrate processing apparatus 1. The control unit 3 is typically a computer and includes a memory 3m for storing information such as programs, and a processor 3p for controlling the substrate processing apparatus 1 according to the information stored in the memory 3m.

[0044] The transport units (IR, SH, CR) include an indexer robot IR, a shuttle SH, and a center robot CR, arranged along a transport path extending from multiple load ports LP to multiple processing units 2. The indexer robot IR transports substrates W between the multiple load ports LP and the shuttle SH. The shuttle SH reciprocates between the indexer robot IR and the center robot CR to transport substrates W. The center robot CR transports substrates W between the shuttle SH and the multiple processing units 2. The center robot CR also transports substrates W between the multiple processing units 2. Figure 1 The bold arrows shown indicate the moving directions of the indexer robot IR and the shuttle SH.

[0045] The processing units 2 form four towers arranged at four horizontally spaced locations. Each tower contains multiple processing units 2 stacked vertically. Two of the four towers are located on each side of the transport path. The processing units 2 include dry processing units 2D, which process substrates W while keeping them dry, and wet processing units 2W, which process substrates W with a processing liquid. The two towers on the load port LP side are composed of dry processing units 2D, while the remaining two towers are composed of wet processing units 2W.

[0046] Figure 2 This is a schematic cross-sectional view illustrating an example configuration of a dry processing unit 2D. The dry processing unit 2D includes a dry chamber 4 having a loading / unloading port 4a through which substrates W pass; a shutter 5 that opens and closes the loading / unloading port 4a; a thermal treatment unit 8 that supplies processing gas to the substrates W while heating them within the dry chamber 4; a cooling unit 7 that cools the substrates W heated by the thermal treatment unit 8 within the dry chamber 4; and an in-chamber transfer mechanism 6 that transfers substrates W within the dry chamber 4. The central robot CR loads and places substrates W into and out of the dry chamber 4 via the loading / unloading port 4a. The cooling unit 7 is located within the dry chamber 4 near the loading / unloading port 4a.

[0047] The cooling unit 7 includes a cold plate 20; lift pins 22 that penetrate the cold plate 20 and move vertically; and a pin lift drive mechanism 23 that moves the lift pins 22 vertically. The cold plate 20 includes a cooling surface 20a on which a substrate W is placed. A coolant path (not shown) circulates a coolant (typically cooling water) within the cold plate 20. The lift pins 22 move vertically between an upper position, where they support the substrate W above the cooling surface 20a, and a lower position, where their tips are sunk below the cooling surface 20a.

[0048] The heat treatment unit 8 includes a heater 33. More specifically, the heat treatment unit 8 comprises a heat plate 30; a heat treatment chamber 34 that houses the heat plate 30; lift pins 38 that penetrate the heat plate 30 and move vertically; and a pin lift drive mechanism 39 that moves the lift pins 38 vertically. The heat plate 30 includes a heating surface 30a on which the substrate W is placed and a built-in heater 33.

[0049] The heater 33 is configured to heat the substrate W placed on the heating surface 30a to a temperature of 150°C or higher. For example, the heater 33 may be configured to heat the substrate W to 250°C. The heating surface 30a mimics the shape of the substrate W and has a planar shape that is slightly larger than the substrate W. Specifically, if the substrate W is circular, the heating surface 30a is formed in a circular shape that is slightly larger than the substrate W.

[0050] The thermal processing chamber 34 includes a chamber body 35 and a lid 36 that moves vertically above the chamber body 35. The thermal processing unit 8 includes a lid lift drive mechanism 37 that lifts and lowers the lid 36. The chamber body 35 has an opening 35a that opens upward, and the lid 36 opens and closes the opening 35a. The lid 36 moves vertically between a closed position (lower position), in which it covers the opening 35a of the chamber body 35, forming a sealed processing space within the chamber body 35, and an upper position, in which it retracts upward, opening the opening 35a. Lift pins 38 move vertically between an upper position, in which they support the substrate W above the heating surface 30a, and a lower position, in which their tips are retracted below the heating surface 30a.

[0051] An exhaust port 41 is formed at the bottom of the chamber body 35. The exhaust ports 41 are preferably arranged at multiple locations (e.g., 3 locations) with intervals in the circumferential direction. The exhaust port 41 is connected to an exhaust device 43 (see FIG. 1 ) via an exhaust line 42. Figure 3 )combined.

[0052] The lid 36 includes a plate portion 45 extending parallel to the heating surface 30a, and a cylindrical portion 46 extending downward from the periphery of the plate portion 45. Specifically, the plate portion 45 is generally circular, and the cylindrical portion 46 has a corresponding cylindrical shape. The lower end of the cylindrical portion 46 faces the upper end of the chamber body 35. Thus, the opening 35a of the chamber body 35 can be opened and closed by moving the lid 36 up and down.

[0053] A gas inlet port 48 is formed through the plate portion 45. In this embodiment, the gas inlet port 48 is formed in the center of the plate portion 45. The gas inlet port 48 is connected to a gas supply line 49. Gas introduced through the gas inlet port 48 is supplied to the processing space below it. Thus, gas is supplied to the substrate W placed in the processing space. The gas is evenly supplied to substantially the entire area of ​​the heating surface 30a (and thus substantially the entire area of ​​the upper surface of the substrate W).

[0054] The indoor transfer mechanism 6 transfers substrates W within the dry chamber 4. More specifically, the indoor transfer mechanism 6 includes an indoor transfer hand 6H that transfers substrates W between the cooling unit 7 and the thermal treatment unit 8. The indoor transfer hand 6H is configured to receive and deliver substrates W between the lift pins 22 of the cooling unit 7 and between the lift pins 38 of the thermal treatment unit 8. Thus, the indoor transfer hand 6H can operate to receive substrates W from the lift pins 22 of the cooling unit 7 and transfer them to the lift pins 38 of the thermal treatment unit 8. Furthermore, the indoor transfer hand 6H can operate to receive substrates W from the lift pins 38 of the thermal treatment unit 8 and transfer them to the lift pins 22 of the cooling unit 7.

[0055] Typical operations of the dry processing unit 2D are as follows.

[0056] Center robot CR (refer to Figure 1 ) When a substrate W is loaded into the dry chamber 4, the shutter 5 is controlled to the open position, opening the loading / unloading port 4a. In this state, the hand H of the central robot CR enters the dry chamber 4 and places the substrate W above the cold plate 20. The lift pins 22 then rise to the upper position, receiving the substrate W from the hand H of the central robot CR. The hand H of the central robot CR then retreats out of the dry chamber 4. Next, the indoor transfer hand 6H of the indoor transfer mechanism 6 receives the substrate W from the lift pins 22 and transfers it to the lift pins 38 of the thermal treatment unit 8. At this point, the lid 36 is in the open position (upper position), and the lift pins 38 support the received substrate W in the upper position. After the indoor transfer hand 6H retreats from the thermal treatment chamber 34, the lift pins 38 descend to the lower position, placing the substrate W on the heated surface 30a. Meanwhile, the lid 36 descends to the closed position (lower position), forming a sealed processing space enclosing the hot plate 30. In this state, thermal treatment of the substrate W proceeds.

[0057] When the heat treatment is completed, the lid 36 rises to the open position (upper position), opening the heat treatment chamber 34. Furthermore, the lift pins 38 rise to the upper position, pushing the substrate W upward above the heating surface 30a. In this state, the indoor transfer hand 6H of the indoor transfer mechanism 6 receives the substrate W from the lift pins 38 and transfers it to the lift pins 22 of the cooling unit 7. The lift pins 22 support the received substrate W in the upper position. Waiting for the indoor transfer hand 6H to retract, the lift pins 22 descend to the lower position, placing the substrate W on the cooling surface 20a of the cold plate 20. This cools the substrate W.

[0058] When cooling of the substrate W is complete, the lift pins 22 rise to their upper positions, thereby pushing the substrate W upwards above the cooling surface 20a. In this state, the shutter 5 opens, and the hand H of the central robot CR enters the dry chamber 4 and is positioned below the substrate W, which is supported by the lift pins 22 in the upper position. In this state, the lift pins 22 descend, transferring the substrate W to the hand H of the central robot CR. The hand H, holding the substrate W, retreats outside the dry chamber 4, and the shutter 5 closes the loading / unloading port 4a.

[0059] Figure 3 This is a system diagram for explaining a configuration example of a gas supply system and an exhaust system for the heat treatment unit 8 .

[0060] Ozone gas supply line 51, room temperature inert gas supply line 52, and high temperature inert gas supply line 53 are connected to gas supply line 49 (piping) connected to gas inlet port 48. Gas supply line 49 is provided with filter 50 for filtering foreign matter in the circulating gas.

[0061] Ozone gas supply line 51 includes piping for supplying ozone gas generated by ozone gas generator 55. The temperature of the ozone gas is less than 150°C, typically at room temperature. An ozone gas valve 56 is installed in ozone gas supply line 51 to open and close its flow path. Ozone gas supply line 51 and ozone gas valve 56 are one example of ozone gas supply means.

[0062] The room-temperature inert gas supply line 52 includes piping for supplying room-temperature inert gas supplied from an inert gas supply source 58. The inert gas is a chemically inert gas such as nitrogen or argon. The room-temperature inert gas supply line 52 supplies the inert gas supplied from the inert gas supply source 58 to the gas supply line 49 without heating. The room-temperature inert gas supply line 52 is equipped with a room-temperature inert gas valve 59 for opening and closing the flow path, a flow control valve 60 for adjusting the flow rate, and a flow meter 61. The room-temperature inert gas supply line 52 and the room-temperature inert gas valve 59 are examples of a room-temperature inert gas supply unit.

[0063] The high-temperature inert gas supply line 53 includes piping for supplying an inert gas at a temperature higher than room temperature. Specifically, the high-temperature inert gas supply line 53 heats and supplies room-temperature inert gas supplied from an inert gas supply source 58. More specifically, a heater 63 is installed in the high-temperature inert gas supply line 53. The heater 63 heats the inert gas flowing through the high-temperature inert gas supply line 53 to a temperature exceeding 150°C. More specifically, the heater 63 heats the inert gas flowing through the high-temperature inert gas supply line 53 so that the processing space within the heat treatment chamber 34 is filled with inert gas at a temperature exceeding 150°C. Upstream of the heater 63, the high-temperature inert gas supply line 53 includes a high-temperature inert gas valve 64 for opening and closing the flow path, a flow control valve 65 for adjusting the flow rate, and a flow meter 66. The high-temperature inert gas supply line 53, heater 63, and high-temperature inert gas valve 64 are examples of a high-temperature inert gas supply unit.

[0064] An exhaust line (pipe) 42 is connected to an exhaust port 41 of the heat treatment chamber 34 . The exhaust line 42 is connected to an exhaust device 43 . Exhaust from the exhaust line 42 is mainly to prevent ozone gas from leaking out of the heat treatment chamber 34 .

[0065] An ozone exhaust line (piping) 68 is connected to the ozone gas supply line 51 upstream of the ozone gas valve 56. The ozone exhaust line 68 is connected to the exhaust device 43. An ozone exhaust valve 69 is installed in the ozone exhaust line 68. The ozone exhaust valve 69 opens to exhaust ozone gas remaining in the ozone gas supply line 51 after the ozone gas generator 55 stops operating.

[0066] Figure 4 It is a schematic cross-sectional view for explaining a configuration example of the wet processing unit 2W.

[0067] The wet processing unit 2W is a single-wafer liquid processing unit that processes substrates W one by one. The wet processing unit 2W includes a box-shaped wet chamber 9 (see Figure 1 ), which divides the internal space; a rotating chuck 70 (substrate holding mechanism, substrate holder), which holds a substrate W in a horizontal position within the wet chamber 9 and rotates the substrate W around a vertical rotation axis A1 passing through the center of the substrate W; an SPM supply unit 71, which supplies a processing liquid containing sulfuric acid (in this embodiment, a sulfuric acid / hydrogen peroxide mixture (SPM)) to the substrate W held on the rotating chuck 70; a cleaning liquid supply unit 72; and a cylindrical cup 73, which surrounds the rotating chuck 70. Figure 1 As shown, the wet chamber 9 has a loading / unloading port 9a through which substrates W pass, and is provided with a shutter 10 for opening and closing the loading / unloading port 9a. The wet chamber 9 is an example of a liquid processing chamber in which substrate processing using a processing liquid is performed.

[0068] The spin chuck 70 includes a disk-shaped spin base 74 that maintains a horizontal position; a plurality of chuck pins 75 above the spin base 74 that maintain the substrate W in a horizontal position; a rotation shaft 76 extending downward from the center of the spin base 74; and a rotation motor 77 that rotates the rotation shaft 76 to rotate the substrate W and the spin base 74 about a rotation axis A1. The spin chuck 70 is not limited to a clamping chuck in which the plurality of chuck pins 75 contact the peripheral end surface of the substrate W. It may also be a vacuum chuck that holds the substrate W horizontally by suctioning the back surface (lower surface) of the substrate W, which is not the device forming surface, against the upper surface of the spin base 74.

[0069] The cup 73 is arranged outside the substrate W held by the spin chuck 70 (in a direction away from the rotation axis A1). The cup 73 surrounds the spin base 74. When the processing liquid is supplied to the substrate W while the spin chuck 70 rotates the substrate W, the cup 73 receives the processing liquid discharged around the substrate W. The processing liquid received by the cup 73 is sent to a recovery device or a liquid drain device (not shown).

[0070] The cleaning liquid supply unit 72 includes a cleaning liquid nozzle 80 for discharging cleaning liquid onto the substrate W held on the spin chuck 70; a cleaning liquid pipe 81 for supplying cleaning liquid to the cleaning liquid nozzle 80; and a cleaning liquid valve 82 for switching the supply of cleaning liquid from the cleaning liquid pipe 81 to the cleaning liquid nozzle 80. The cleaning liquid nozzle 80 may also be a fixed nozzle that discharges cleaning liquid while the nozzle of the cleaning liquid nozzle 80 is stationary. The cleaning liquid supply unit 72 may also include a cleaning liquid nozzle moving unit that moves the cleaning liquid nozzle 80 to adjust the landing position of the cleaning liquid on the upper surface of the substrate W.

[0071] When the cleaning liquid valve 82 is opened, the cleaning liquid supplied from the cleaning liquid pipe 81 to the cleaning liquid nozzle 80 is ejected from the cleaning liquid nozzle 80 toward the center of the upper surface of the substrate W. The cleaning liquid is, for example, pure water (deionized water). The cleaning liquid is not limited to pure water; it may also be carbonated water, electrolytic ionized water, hydrogen water, ozone water, or hydrochloric acid water with a diluted concentration (e.g., approximately 10 to 100 ppm). The temperature of the cleaning liquid may be room temperature or a temperature higher than room temperature (e.g., 70 to 90°C).

[0072] The SPM supply unit 71 includes an SPM nozzle 85 for ejecting SPM onto the upper surface of the substrate W, a nozzle arm 86 having the SPM nozzle 85 mounted at its tip, and a nozzle moving unit 87 for moving the SPM nozzle 85 by moving the nozzle arm 86 .

[0073] The SPM nozzle 85 is, for example, a linear nozzle that discharges SPM in a continuous stream, and is mounted on a nozzle arm 86 in a vertical position for discharging the processing liquid in a direction perpendicular to the upper surface of the substrate W. The nozzle arm 86 extends horizontally and is rotatably provided around the spin chuck 70 about a swing axis (not shown) extending in the vertical direction.

[0074] The nozzle moving unit 87 rotates the nozzle arm 86 about the swing axis to horizontally move the SPM nozzle 85 along a trajectory that passes through the center of the upper surface of the substrate W when viewed from above. The nozzle moving unit 87 moves the SPM nozzle 85 between a processing position where the SPM liquid ejected from the SPM nozzle 85 lands on the upper surface of the substrate W and an initial position where the SPM nozzle 85 is located around the spin chuck 70 when viewed from above. The processing positions include a central position where the SPM liquid ejected from the SPM nozzle 85 lands on the center of the upper surface of the substrate W and a peripheral position where the SPM liquid ejected from the SPM nozzle 85 lands on the peripheral edge of the upper surface of the substrate W.

[0075] The SPM supply unit 71 includes a sulfuric acid pipe 89 connected to the SPM nozzle 85 and supplied with sulfuric acid (H 2 SO 4 ) from a sulfuric acid supply source 88 ; and a hydrogen peroxide solution pipe 95 connected to the SPM nozzle 85 and supplied with hydrogen peroxide solution (H 2 O 2 ) from a hydrogen peroxide solution supply source 94 .

[0076] The sulfuric acid supplied from the sulfuric acid supply source 88 and the hydrogen peroxide solution supplied from the hydrogen peroxide solution supply source 94 are both aqueous solutions. The concentration of the sulfuric acid is, for example, 90 to 98%, and the concentration of the hydrogen peroxide solution is, for example, 30 to 50%.

[0077] A sulfuric acid valve 90 for opening and closing the flow path of sulfuric acid piping 89, a sulfuric acid flow regulating valve 91 for adjusting the flow rate of sulfuric acid, and a heater 92 for heating sulfuric acid are installed in this order from the SPM nozzle 85 side. Heater 92 heats the sulfuric acid to a temperature higher than room temperature (a constant temperature within the range of 70 to 190°C, for example, 90°C).

[0078] A hydrogen peroxide solution valve 96 for opening and closing the flow path of the hydrogen peroxide solution pipe 95 and a hydrogen peroxide solution flow rate regulating valve 97 for adjusting the flow rate of the hydrogen peroxide solution are interposed in this order from the SPM nozzle 85 side. Unregulated hydrogen peroxide solution at room temperature (e.g., approximately 23° C.) is supplied to the hydrogen peroxide solution valve 96 through the hydrogen peroxide solution pipe 95.

[0079] The SPM nozzle 85 has, for example, a substantially cylindrical housing. A mixing chamber is formed within the housing. A sulfuric acid pipe 89 is connected to a sulfuric acid inlet located on a side wall of the SPM nozzle 85 housing. A hydrogen peroxide solution pipe 95 is connected to a hydrogen peroxide solution inlet located on a side wall of the SPM nozzle 85 housing.

[0080] When the sulfuric acid valve 90 and the hydrogen peroxide solution valve 96 are opened, sulfuric acid (high-temperature sulfuric acid) from the sulfuric acid piping 89 is supplied from the sulfuric acid inlet of the SPM nozzle 85 to the mixing chamber inside it, and hydrogen peroxide solution from the hydrogen peroxide solution piping 95 is supplied from the hydrogen peroxide solution inlet of the SPM nozzle 85 to the mixing chamber inside it.

[0081] The sulfuric acid and hydrogen peroxide solution flowing into the mixing chamber of the SPM nozzle 85 are thoroughly stirred and mixed in the mixing chamber. Through the mixing, the sulfuric acid and hydrogen peroxide solution are uniformly mixed, and SPM (sulfuric acid hydrogen peroxide solution mixture) is generated through the reaction. SPM contains peroxymonosulfuric acid (H2SO5) with strong oxidizing power. Since the sulfuric acid heated to a high temperature is supplied, and the mixing of the sulfuric acid and hydrogen peroxide solution is an exothermic reaction, high-temperature SPM is generated. Specifically, SPM is generated at a temperature higher than the temperature of either the sulfuric acid or hydrogen peroxide solution before mixing (above 100°C, for example, 160°C). The high-temperature SPM generated in the mixing chamber of the SPM nozzle 85 is ejected toward the substrate W from the ejection port opening toward the front end (lower end) of the housing.

[0082] Figure 5This is a block diagram illustrating an example configuration related to control of a substrate processing apparatus 1. The control apparatus 3 is comprised of, for example, a microcomputer. The control apparatus 3 includes a memory 3m that stores information such as programs, and a processor 3p (CPU (Central Processing Unit)) that controls the substrate processing apparatus 1 according to the information stored in the memory 3m. A program indicating the processing sequence and steps for substrates W is stored in the memory 3m. The control apparatus 3 is configured (programmed) to control the substrate processing apparatus 1 based on the program stored in the memory 3m to execute processing on the substrates W.

[0083] The specific control objects of the control device 3 are the indexer robot IR, the shuttle SH, the center robot CR, the indoor conveying mechanism 6, the pin lifting drive mechanisms 23 and 39, the heater 33, the cover lifting drive mechanism 37, the ozone gas generator 55, the ozone gas valve 56, the room temperature inert gas valve 59, the flow adjustment valve 60, the heater 63, the high temperature inert gas valve 64, the flow adjustment valve 65, the ozone exhaust valve 69, the rotary motor 77, the cleaning liquid valve 82, the nozzle moving unit 87, the sulfuric acid valve 90, the sulfuric acid flow adjustment valve 91, the heater 92, the hydrogen peroxide water valve 96, the hydrogen peroxide water flow adjustment valve 97, etc.

[0084] Figures 6A to 6C A typical example of substrate processing performed using the substrate processing device 1 is shown. The substrate W to be processed is, for example, a silicon substrate (silicon wafer). A film of resist 100 is formed on the surface of the substrate W. The resist 100 is a resist used as a mask for selectively injecting ions into the substrate W. In particular, in the resist 100 on the substrate W after a high-dose ion implantation process, a hardened layer 101 is formed on its surface portion. The hardened layer 101 is formed by carbonization or other deterioration of the resist 100. On the lower side of the hardened layer 101 (on the surface side of the substrate W), there is an unhardened resist layer 102 (hereinafter referred to as "non-hardened layer 102"). Here, a substrate processing in which the resist 100 having the hardened layer 101 on the surface portion is peeled off or removed from the surface of the substrate W, that is, a resist peeling process or a resist removal process, is described.

[0085] The substrate treatment includes ozone treatment ( Figure 6A ) and SPM treatment ( Figure 6B ).

[0086] Ozone treatment (refer to Figure 6A) is a process of heating the substrate W and supplying ozone gas to the surface of the heated substrate W (more specifically, the hardened layer 101 of the resist 100). The heating temperature, that is, the temperature of the substrate W in the heated state is set to above 150°C. When the ozone gas reaches the surface of the substrate W, the ozone gas receives heat from the substrate W and is heated. As a result, the ozone gas is decomposed into oxygen and oxygen free radicals. The oxygen free radicals thus generated react with the hardened layer 101, and the hardened layer 101 volatilizes in the atmosphere. As a result, the hardened layer 101 is removed. In other words, the ozone treatment is a hardened layer removal treatment for removing the hardened layer 101 of the resist 100. The hardened layer 101 is at least partially removed, preferably completely removed.

[0087] SPM treatment (refer to Figure 6B ) is performed after the ozone treatment (hardened layer removal treatment). The SPM treatment is a liquid treatment in which SPM is supplied to the surface of the substrate W (the surface on which the resist 100 is formed). SPM has the function of removing the hardened layer 101 and the non-hardened layer 102 of the resist 100, but the removal rate of the hardened layer is much lower than the removal rate of the non-hardened layer. Therefore, if there is a hardened layer 101 on the surface of the resist 100, the resist 100 (non-hardened layer 102) on the surface of the substrate W can be quickly removed by supplying SPM (refer to Figure 6C ). Even if a small amount of hardened layer 101 remains on the surface of the resist 100, the removal of the small amount of hardened layer 101 can also be achieved by a short-time SPM treatment, so the resist 100 can still be removed in a short time. Moreover, even if a hardened layer 101 remains on the surface of the resist 100, if there is an exposed portion of the non-hardened layer 102, that is, there is a liquid path that penetrates the hardened layer 101 to reach the non-hardened layer 102, then the SPM will also penetrate into the non-hardened layer 102 and remove the non-hardened layer 102. Thus, the hardened layer 101 is peeled off together with the non-hardened layer 102, so the entire resist 100 can still be removed from the surface of the substrate W by a short-time SPM treatment.

[0088] Thus, by using ozone treatment ( Figure 6A ) After removing the hardened layer 101, SPM treatment is performed ( Figure 6B ), compared with the case where the SPM treatment is performed without the ozone treatment, the resist 100 can be removed quickly from the surface of the substrate W ( Figure 6C ).

[0089] Figure 7 This is a diagram used to illustrate the thermal decomposition of ozone gas. It is known that ozone (O3) causes thermal decomposition by imparting energy greater than the active energy, generating oxygen free radicals. The decomposition rate (chemical reaction rate constant k1) increases as the temperature rises. Figure 7It can be seen that the chemical reaction rate constant k1 is greater than 0, and oxygen radicals are generated at temperatures above 150°C. Therefore, by setting the temperature of the ozone-treated substrate W to 150°C or higher, a thermal decomposition reaction can occur near the substrate surface, allowing the generated oxygen radicals to act on the hardened resist layer. To avoid cracking of the resist, the temperature of the substrate W during heating is preferably set to 170°C or lower.

[0090] Thermal decomposition of ozone gas can also be used to render it harmless. Specifically, if ozone gas remains in the heat treatment chamber 34 after ozone treatment, it can be thermally decomposed by heating the ozone gas to a temperature of 150°C or higher. Oxygen radicals generated by thermal decomposition have a short lifespan and quickly disappear into oxygen, making them essentially harmless.

[0091] Figure 8A and Figure 8B This is a flowchart for explaining a specific substrate processing flow in the substrate processing apparatus 1 . Figure 8A Indicates the details of ozone treatment (hardened layer removal treatment), Figure 8B The following SPM processing is detailed. The processing is achieved by the control device 3 controlling the corresponding control object.

[0092] An unprocessed substrate W is removed by the indexer robot IR and transferred to the shuttle SH. The center robot CR receives the substrate W and transports it into the dry chamber 4. The substrate W transported into the dry chamber 4 is transferred to the lift pins 38 of the thermal treatment unit 8 via the indoor transfer mechanism 6. The lift pins 38 descend and place the substrate W on the heated surface 30a of the hot plate 30 (step S1). The lid 36 then descends, leaving the substrate W placed on the hot plate 30 within the sealed space formed by the chamber body 35 and the lid 36.

[0093] The hot plate 30 performs a heating step (step S2) of heating the substrate W placed on the heating surface 30a to 150°C to 170°C (for example, 170°C). In parallel with the heating step, ozone gas is introduced into the heat treatment chamber 34, and an ozone gas supply step (step S3) is performed. That is, by opening the ozone gas valve 56, ozone gas is introduced from the gas inlet port 48, and the internal atmosphere of the heat treatment chamber 34 is exhausted from the exhaust port 41. As a result, the air in the heat treatment chamber 34 is replaced with ozone gas, and the ozone gas reaches the surface of the substrate W heated on the hot plate 30 (more specifically, the surface of the hardened layer). As a result, thermal decomposition of the ozone gas occurs on the surface of the substrate W, generating oxygen free radicals. The hardened layer of the resist is removed by the action of the oxygen free radicals. The treatment is carried out for a predetermined specific time (for example, about 30 seconds). The ozone gas introduced into the heat treatment chamber 34 does not reach 150°C (typically room temperature). The concentration of the ozone gas may also be, for example, 100 to 200 g / cm 3 In addition, the supply flow rate of ozone gas may be approximately 5 to 20 liters per minute.

[0094] When the hardened layer removal treatment using oxygen free radicals is completed, the control device 3 closes the ozone gas valve 56, stops the supply of ozone gas (step S4), and instead opens the high-temperature inert gas valve 64. Thus, the high-temperature inert gas is introduced into the heat treatment chamber 34 from the gas inlet port, and the high-temperature inert gas supply step (step S5) is performed. The high-temperature inert gas is supplied to the heat treatment chamber 34 while maintaining a temperature of 150°C or above (for example, 170°C). Thus, the ozone gas remaining in the heat treatment chamber 34 is thermally decomposed. In particular, there is a portion where gas stagnation occurs in the heat treatment chamber 34, such as the periphery of the cylindrical portion 46 of the cover 36 (refer to Figure 2 By supplying high-temperature inert gas to such a stagnant area, the stagnant ozone gas is thermally decomposed and quickly rendered harmless. The supply of high-temperature inert gas is carried out for about 10 seconds, for example.

[0095] Furthermore, even when the substrate W is heated to 150°C or higher (e.g., approximately 170°C) by the hot plate 30, the temperature of the lid 36 and other components does not reach 150°C (e.g., approximately 100°C), and thermal decomposition of ozone does not occur at locations away from the substrate W and the hot plate 30. In other words, even within the heat treatment chamber 34, the temperature of components located away from the substrate W, particularly components in the ozone gas supply path toward the substrate W, remains below 150°C, thereby suppressing thermal decomposition of ozone before it reaches the substrate W. Consequently, thermal decomposition of ozone can be effectively induced near the surface of the substrate W, thereby improving processing efficiency.

[0096] Next, the control device 3 closes the high-temperature inert gas valve 64 and opens the room-temperature inert gas valve 59 instead. Thus, room-temperature inert gas is introduced into the heat treatment chamber 34 from the gas inlet port 48, and the room-temperature inert gas supply step (step S6) is performed. Thus, the atmosphere inside the heat treatment chamber 34 is replaced with room-temperature inert gas. Thus, the heat treatment chamber 34 is cooled. The room-temperature inert gas supply can be, for example, for 30 seconds or less. Thereafter, the control device 3 closes the room-temperature inert gas valve 59.

[0097] Next, the controller 3 retracts the lid 36 upward, opening the heat treatment chamber 34. The lift pins 38 then push the substrate W upward, and the lifted substrate W is transported to the cooling unit 7 by the in-chamber transport mechanism 6 and transferred to the lift pins 22. As the lift pins 22 descend, the substrate W is placed on the cold plate 20 and cooled (step S7). This cools the substrate W to approximately room temperature. After the substrate cooling process, the lift pins 22 push the substrate W upward, and the central robot CR unloads the substrate W out of the dry chamber 4 (step S8).

[0098] The central robot CR carries the substrate W into the wet chamber 9 (step S11) for SPM processing (wet processing step). Specifically, the control device 3 controls the central robot CR holding the substrate W (see Figure 1 ), the hand H enters the wet chamber 9, thereby placing the substrate W on the spin chuck 70 with its surface (the surface on which the resist is formed) facing upward. The control device 3 then starts rotating the substrate W using the rotation motor 77 (step S12). The rotation speed of the substrate W is increased to a predetermined processing rotation speed (within the range of 100 to 500 rpm, for example, approximately 300 rpm) and maintained at that processing rotation speed.

[0099] When the rotation speed of the substrate W reaches the processing rotation speed, the control device 3 performs an SPM processing step (step S13) in which a processing liquid containing sulfuric acid, namely, SPM, is supplied to the substrate W. Specifically, the control device 3 controls the nozzle moving unit 87 to move the SPM nozzle 85 from the initial position to the processing position. This positions the SPM nozzle 85 above the substrate W.

[0100] After the SPM nozzle 85 is positioned above the substrate W, the controller 3 opens the sulfuric acid valve 90 and the hydrogen peroxide solution valve 96. Thus, the hydrogen peroxide solution flowing through the hydrogen peroxide solution pipe 95 and the sulfuric acid flowing through the sulfuric acid pipe 89 are supplied to the SPM nozzle 85. As a result, the sulfuric acid and the hydrogen peroxide solution are mixed in the mixing chamber of the SPM nozzle 85, generating high-temperature (e.g., 160°C) SPM (generating step). The high-temperature SPM is ejected from the ejection port of the SPM nozzle 85 and lands on the upper surface of the substrate W (supplying step). The controller 3 controls the nozzle moving unit 87 to move the SPM landing position relative to the upper surface of the substrate W between the center and the periphery.

[0101] After the SPM ejected from the SPM nozzle 85 lands on the upper surface of the substrate W rotating at a processing rotational speed (e.g., 300 rpm), it flows outward along the upper surface of the substrate W due to centrifugal force. As a result, the SPM is supplied to the entire upper surface of the substrate W, forming an SPM liquid film covering the entire upper surface of the substrate W. This process is performed for a specific SPM processing time (e.g., approximately 30 seconds), thereby removing the resist on the surface of the substrate W by the SPM.

[0102] When a specific SPM processing time has elapsed since the start of SPM discharge, the SPM processing step ends (step S13). Specifically, the control device 3 closes the hydrogen peroxide valve 96 and the sulfuric acid valve 90. Furthermore, the control device 3 controls the nozzle moving unit 87 to move the SPM nozzle 85 from the processing position to the initial position. This causes the SPM nozzle 85 to retract from above the substrate W.

[0103] Next, a cleaning liquid supply step (step S14) is performed to supply cleaning liquid to the substrate W. Specifically, the control device 3 opens the cleaning liquid valve 82, and the cleaning liquid is sprayed from the cleaning liquid nozzle 80 toward the center of the upper surface of the substrate W. The cleaning liquid sprayed from the cleaning liquid nozzle 80 displaces and rinses the SPM on the substrate W. When a specific cleaning liquid supply time has elapsed since the cleaning liquid valve 82 was opened, the control device 3 closes the cleaning liquid valve 82, stopping the spraying of cleaning liquid from the cleaning liquid nozzle 80.

[0104] Next, a drying step is performed to dry the substrate W (step S15). Specifically, the control device 3 controls the spin motor 77 to accelerate the substrate W to a drying rotation speed (e.g., several thousand rpm), rotating the substrate W at the drying rotation speed. This causes a large centrifugal force to be applied to the liquid adhering to the substrate W, causing the liquid to be flung toward the periphery of the substrate W. This removes the liquid from the substrate W, drying the substrate W. Furthermore, after a predetermined period of time has elapsed since the start of the high-speed rotation of the substrate W, the control device 3 controls the spin motor 77 to stop the rotation of the substrate W by the spin chuck 70 (step S16).

[0105] Next, a carry-out step (step S17) is performed to carry the substrate W out of the wet chamber 9. Specifically, the controller 3 causes the hand H of the central robot CR to enter the wet chamber 9, hold the substrate W on the spin chuck 70, and then withdraw the hand H from the wet chamber 9. This allows the processed substrate W to be carried out of the chamber.

[0106] The center robot CR transfers the substrate W to the shuttle SH. The shuttle SH transports the substrate W to the indexer robot IR. The indexer robot IR receives the processed substrate W from the shuttle SH and stores it in a carrier C.

[0107] Figure 9A and Figure 9B This figure is used to illustrate the effect of resist stripping by ozone treatment and high temperature SPM treatment. Specifically, a resist is formed on the surface of a silicon wafer, and an ozone treatment is performed with an energy of 10 keV and a dose of 1×10 15 ions / cm 2 A substrate to be treated with phosphorus ion implantation is set as a treatment target.

[0108] Figure 9A The following table shows the results of a comparative example in which such a substrate was treated with only high-temperature SPM, i.e., without ozone treatment, and subjected to resist removal. As Comparative Example 1, after supplying high-temperature SPM at a flow rate of 900 ml / min for 90 seconds, the number of foreign particles (particles with a diameter of 88 nm or larger) on the substrate was measured using a particle counter. The result was over 110. As Comparative Example 2, after supplying high-temperature SPM at the same flow rate (900 ml / min) for 120 seconds, the number of foreign particles (particles with a diameter of 88 nm or larger) on the substrate was measured using a particle counter. The result was approximately 10.

[0109] on the other hand, Figure 9B As Example 1, the results of resist removal treatment are shown for the substrate as described above through ozone treatment and subsequent high-temperature SPM treatment. The substrate temperature is set to 170°C and the treatment time is set to 30 seconds for the ozone treatment. After the ozone treatment, the high-temperature SPM is supplied at a flow rate of 900 ml / min for 60 seconds, and the number of foreign matter (particle diameter of 88 nm or more) on the substrate is measured by a particle counter. The measurement result is about 10. As Example 2, after the same ozone treatment as Example 1, the high-temperature SPM is supplied at a flow rate of 900 ml / min for 30 seconds, and the number of foreign matter (particle diameter of 88 nm or more) on the substrate is measured by a particle counter. The measurement result is about 10. Therefore, a high-temperature SPM treatment time of about 30 seconds is sufficient, thereby obtaining a result roughly equivalent to the case of a 120-second high-temperature SPM treatment.

[0110] Figure 10A and Figure 10BRepresents the results of experiments investigating the effects of treatments on substrates.

[0111] Figure 10A The following table shows the results of measuring SiN film reduction (thickness reduction) on substrates (silicon wafers) with a SiN film formed on their surfaces, subjected to Comparative Example 2 (120-second high-temperature SPM treatment) and Example 2 (ozone treatment followed by 30-second high-temperature SPM treatment). It can be seen that Example 2 exhibits less film reduction than Comparative Example 2, indicating less impact on the SiN film.

[0112] Figure 10B The results of measuring oxide film growth are shown for bare silicon wafers subjected to the treatments of Comparative Example 2 (120 seconds of high-temperature SPM treatment) and Example 2 (ozone treatment and 30 seconds of high-temperature SPM treatment). It is found that the oxide film growth is substantially the same.

[0113] As described above, the resist removal process of the ozone treatment followed by the high-temperature SPM treatment is comparable to the resist removal process using only the high-temperature SPM treatment in terms of the effect on the substrate.

[0114] As described above, according to this embodiment, a hardened layer removal step is performed by supplying ozone gas at a temperature below 150°C to the surface of substrate W while the substrate W is heated to above 150°C. Since a wet treatment step is performed after removing the hardened layer, in which high-temperature SPM is supplied to the surface of substrate W, SPM easily enters the non-hardened layer (bulk resist layer) between the hardened layer and the surface of substrate W, stripping the resist from the surface of substrate W in a short period of time. This shortens the liquid treatment time using SPM, thereby improving productivity. Furthermore, SPM consumption, particularly sulfuric acid, its raw material, can be reduced. This reduces the environmental impact. As described above, compared to a process that removes a hardened layer of resist primarily using liquid treatment with high-temperature SPM without ozone treatment, this method is advantageous in terms of reducing SiN film and oxide film growth, and the substrate processing quality is not compromised. In other words, SPM (especially sulfuric acid) consumption can be reduced in a short period of time, while achieving a resist stripping process equivalent to a liquid treatment using only SPM.

[0115] In this embodiment, a hot plate 30 for heating a substrate W is placed within a heat treatment chamber 34 that can be sealed by closing a lid 36. Ozone gas at a temperature below 150°C is introduced into the heat treatment chamber 34. Therefore, the ozone gas thermally decomposes near the surface of the substrate W, which has been heated to a temperature above 150°C. The oxygen radicals generated by the thermal decomposition can then reliably act on the hardened layer of the resist. Consequently, the hardened layer can be effectively removed.

[0116] On the other hand, in this embodiment, after the hardened layer removal step using ozone treatment, a high-temperature inert gas heated to above 150°C is introduced into the heat treatment chamber 34. This rapidly thermally decomposes the ozone present in the heat treatment chamber 34. This allows the atmosphere within the heat treatment chamber 34 to be quickly rendered harmless, allowing for rapid removal of the processed substrate W. Consequently, the time required for the ozone treatment can be shortened, contributing to improved productivity.

[0117] Before opening the lid 36 of the heat treatment chamber 34, room temperature inert gas is introduced into the heat treatment chamber 34. This is not to replace the ozone gas within the heat treatment chamber 34, but rather to cool the heat treatment chamber 34 (particularly its internal atmosphere). Therefore, a short inert gas supply is sufficient. Furthermore, this short inert gas supply allows for rapid cooling of the heat treatment chamber 34, shortening the time until the substrate W is removed. This, in turn, shortens processing time, thereby contributing to improved productivity.

[0118] If the high-temperature inert gas supply step is omitted, it is appropriate to supply the room-temperature inert gas to the heat treatment chamber 34 for about 180 seconds, for example, in order to remove the ozone in the heat treatment chamber 34 with the room-temperature inert gas.

[0119] As mentioned above, although one embodiment of the present invention has been described, the present invention can be implemented in other forms.

[0120] For example, the above embodiments describe an example in which a dry process with ozone treatment and a wet process with SPM are performed in separate processing units (i.e., separate chambers). However, ozone treatment and wet process with SPM can also be performed in the same processing unit (within the same chamber). However, since switching between dry (ozone) and wet processes requires maintaining the chamber environment, performing both dry and wet processes in separate chambers is preferred for more efficient substrate processing.

[0121] In addition, in the above embodiment, SPM is cited as an example of a resist stripping liquid as a processing liquid containing sulfuric acid, but other examples of the resist stripping liquid include a sulfuric acid-ozone liquid obtained by mixing ozone with sulfuric acid, a fluoric acid-sulfuric acid-hydrogen peroxide water mixture obtained by adding fluoric acid to sulfuric acid-hydrogen peroxide water, and sulfuric acid alone.

[0122] Although the embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical content of the present invention. The present invention should not be construed as being limited to these specific examples, and the scope of the present invention is defined only by the appended claims.

Claims

1. A substrate processing method for removing a resist having a hardened layer from a substrate surface, comprising: a hardened layer removing step comprising a heating step of heating the substrate to 150° C. or higher, and an ozone gas supplying step of supplying ozone gas to the surface of the substrate heated in the heating step, thereby generating oxygen radicals near the surface of the substrate to remove the hardened layer; and a wet treatment step of supplying a treatment liquid containing sulfuric acid to the substrate surface after the hardened layer removal step to remove the resist from the substrate surface; The heating step is performed by placing the substrate on a hot plate disposed in a heat treatment chamber. The ozone gas supplying step is performed by introducing ozone gas into the heat treatment chamber. The substrate processing method further includes, after stopping the ozone gas supply step and completing the hardened layer removal step, a high-temperature inert gas supply step of introducing an inert gas at a temperature of 150° C. or higher into the heat treatment chamber, supplying the inert gas at a temperature of 150° C. or higher to a retention area in the heat treatment chamber where gas retention occurs, and thermally decomposing the ozone gas retained in the retention area to render it harmless. 2 . The substrate processing method according to claim 1 , further comprising, after the high-temperature inert gas supplying step, a room-temperature inert gas supplying step of introducing a room-temperature inert gas into the heat treatment chamber. 3 . The substrate processing method according to claim 1 , wherein the ozone gas supplying step supplies ozone gas having a temperature lower than 150° C. to the surface of the substrate.

4. A substrate processing apparatus comprising: a substrate heating unit having a heat treatment chamber for accommodating a substrate, capable of heating the substrate to a temperature above 150° C. within the heat treatment chamber; an ozone gas supply unit for supplying ozone gas into the heat treatment chamber; a processing liquid supply unit for supplying a processing liquid containing sulfuric acid to the substrate; a high-temperature inert gas supply unit for supplying an inert gas having a temperature of 150° C. or higher into the heat treatment chamber; and a control device for controlling the substrate heating unit, the ozone gas supply unit, and the high-temperature inert gas supply unit, After stopping the introduction of ozone gas from the ozone gas supply unit into the heat treatment chamber, the control device controls the high-temperature inert gas supply unit to introduce an inert gas with a temperature of 150° C. or higher into the heat treatment chamber, so that the inert gas with a temperature of 150° C. or higher is supplied to a retention area in the heat treatment chamber where gas retention occurs, and the ozone gas retained in the retention area is thermally decomposed and rendered harmless.

5. The substrate processing apparatus according to claim 4, further comprising a room temperature inert gas supply unit for supplying room temperature inert gas into the heat treatment chamber. The control device controls the room temperature inert gas supply unit to introduce the room temperature inert gas into the heat treatment chamber after the high temperature inert gas supply unit introduces the inert gas at a temperature of 150° C. or higher into the heat treatment chamber. 6 . The substrate processing apparatus according to claim 4 , wherein the ozone gas supply unit supplies ozone gas having a temperature lower than 150° C. into the heat treatment chamber. 7 . The substrate processing apparatus according to claim 4 , wherein the substrate heating unit includes a hot plate on which a substrate is placed. 8 . The substrate processing apparatus according to claim 4 , wherein the processing liquid supply unit is configured to supply the processing liquid containing sulfuric acid to the substrate in a liquid processing chamber separate from the heat processing chamber.

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