Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method capable of enhancing an etching rate of an amorphous carbon film.SOLUTION: A substrate processing method includes: an ozone gas etching step of etching an amorphous carbon film AC in a state where a front surface of a substrate W is dried by supplying an ozone gas as an etching gas to the amorphous carbon film AC formed onto the front surface of the substrate W while heating the substrate W; and a sulfuric acid ozone etching step of etching the amorphous carbon film AC by supplying an ozone-containing sulfuric acid as a sulfuric acid into which the ozone gas is melted as a melting gas to the amorphous carbon film AC after the ozone gas is supplied to the amorphous carbon film AC.SELECTED DRAWING: Figure 1A-F

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses heating a substrate while the substrate is disposed in a processing chamber filled with ozone gas and a liquid film of sulfuric acid is formed on the main surface of the substrate. Paragraph 0008 of Patent Document 1 describes that "an organic film such as a resist is quickly and sufficiently removed from the substrate."

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although Patent Document 1 mentions an organic film such as a resist, there is no description about organic films other than the resist.

[0005] Therefore, one object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of increasing the etching rate of an amorphous carbon film.

Means for Solving the Problems

[0006] One embodiment of the present invention provides a substrate processing method including an ozone gas etching step of etching an amorphous carbon film on a surface of a substrate in a dry state by supplying ozone gas, which is an etching gas, to the amorphous carbon film while heating the substrate, and a sulfuric acid ozone etching step of etching the amorphous carbon film by supplying ozone-containing sulfuric acid, which is sulfuric acid in which ozone gas, a dissolving gas, is dissolved, to the amorphous carbon film after supplying the ozone gas to the amorphous carbon film.

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

[0008] The sulfuric acid ozone etching step includes a step of supplying the ozone-containing sulfuric acid to the amorphous carbon film while heating the substrate.

[0009] The ozone gas etching step includes a step of forming an oxide film of the amorphous carbon film on a surface layer of the amorphous carbon film by oxidizing a surface of the amorphous carbon film exposed by etching the amorphous carbon film, and the sulfuric acid ozone etching step includes a step of etching the oxide film of the amorphous carbon film by supplying the ozone-containing sulfuric acid to the amorphous carbon film.

[0010] One cycle including the ozone gas etching step and the sulfuric acid ozone etching step is performed multiple times.

[0011] The sulfuric acid ozone etching step includes a step of forming a liquid film of the ozone-containing sulfuric acid that covers the entire surface of the substrate by discharging sulfuric acid toward the surface of the substrate in a state where the substrate is horizontally held so that the surface of the substrate faces upward and the accommodation space in which the substrate is disposed is filled with ozone gas.

[0012] The sulfuric acid ozone etching step includes a step of stagnating the ozone-containing sulfuric acid on the surface of the substrate while maintaining a state in which the entire surface of the substrate is covered with a liquid film of the ozone-containing sulfuric acid.

[0013] Another embodiment of the present invention provides a substrate processing apparatus including a heater for heating a substrate having an amorphous carbon film formed on its surface, an ozone gas supply port for supplying ozone gas, which is an etching gas, to the amorphous carbon film formed on the surface of the substrate so as to etch the amorphous carbon film with the surface of the substrate being in a dry state, and a nozzle for supplying ozone-containing sulfuric acid, which is sulfuric acid in which ozone gas, which is a dissolving gas, is dissolved, to the amorphous carbon film formed on the surface of the substrate so as to etch the amorphous carbon film after supplying the ozone gas to the amorphous carbon film. At least one of the foregoing features related to the substrate processing method may be added to the substrate processing apparatus.

Brief Description of the Drawings

[0014]

Fig. 1A-F

Fig. 2

Fig. 3A-B

Fig. 4A

Fig. 4B

Fig. 5A

Fig. 5B

Fig. 6A

Fig. 6B

Fig. 7A

Fig. 7B

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0016] Figures 1A to 1F are schematic cross-sectional views of a substrate W for explaining the etching of an amorphous carbon film AC according to an embodiment of the present invention. Figure 2 is a process diagram for explaining the etching of an amorphous carbon film AC according to an embodiment of the present invention. The etching rate corresponds to the etching speed which is the amount of etching per unit time.

[0017] The amorphous carbon film AC is a film mainly composed of amorphous carbon (non-crystalline carbon). The amorphous carbon contained in the amorphous carbon film AC may or may not contain atoms other than carbon atoms such as hydrogen atoms. The amorphous carbon contained in the amorphous carbon film AC may be a-C (amorphous carbon) with a hydrogen content of 5 at% (atomic percent: atomic percentage) or less and an sp3 structure of 20 to 50%, or may be amorphous carbon other than a-C.

[0018] When etching the amorphous carbon film AC exposed on the surface of the substrate W, an ozone gas etching step (step S1 in FIG. 2) of etching the amorphous carbon film AC while keeping the substrate W dry by supplying ozone gas, which is an etching gas, to the substrate W, and a sulfuric acid ozone etching step (step S2 in FIG. 2) of etching the amorphous carbon film AC by supplying SOM (Sulfuric acid and Ozone Mixture), which is sulfuric acid containing ozone, to the substrate W are performed.

[0019] When performing the ozone gas etching step, as shown in FIG. 1A, the substrate W is horizontally arranged in the accommodation space SP1 with the surface of the substrate W facing upward. In this state, ozone gas, which is an etching gas, is supplied to the upper surface of the substrate W while heating the substrate W. The accommodation space SP1 is a space formed by a physical object such as a partition. As long as ozone gas with a concentration capable of etching the amorphous carbon film AC can be supplied to the upper surface of the substrate W, the accommodation space SP1 may be an open space.

[0020] When the ozone gas etching step is being performed, the substrate W is heated at a temperature higher than room temperature (for example, 20 to 30°C). During the ozone gas etching step, the temperature of the substrate W may be maintained at a constant value higher than room temperature, or may be changed within a range higher than room temperature. The heating of the substrate W may be performed by a contact-type heater that contacts the substrate W, such as a hot plate, or by a non-contact-type heater that does not contact the substrate W, such as a lamp. For example, the substrate W may be heated while being horizontally held by bringing a hot plate into contact with the lower surface of the substrate W. If the heated hot plate is brought close to the substrate W, the substrate W can be heated without bringing the hot plate into contact with the substrate W. Therefore, the hot plate is also an example of a non-contact-type heater.

[0021] As shown in FIG. 1A, in the ozone gas etching process, ozone gas is brought into contact with the upper surface of the substrate W by filling the accommodation space SP1 with ozone gas. When bringing ozone gas into contact with the upper surface of the substrate W, the ozone gas may be supplied while the substrate W is stationary, or the ozone gas may be supplied while rotating the substrate W around a vertical rotation axis passing through the central portion of the substrate W. The supply of ozone gas to the accommodation space SP1 may start simultaneously with the start of heating the substrate W, or may start before or after the start of heating the substrate W. The supply of ozone gas to the accommodation space SP1 may be performed after or while discharging the gas in the accommodation space SP1.

[0022] Ozone gas is a gas in which the concentration of ozone is higher than the concentration of ozone in the atmosphere (for example, 0.005 ppm). Ozone molecules contained in the ozone gas oxidize the amorphous carbon film AC exposed on the surface of the substrate W. As shown in FIG. 1B, ozone molecules contained in the ozone gas change into radicals containing oxygen atoms such as oxygen radicals. Such radicals also oxidize the amorphous carbon film AC. When two carbon atoms contained in the amorphous carbon film AC are double-bonded, the oxidation may include an oxidative cleavage reaction that changes the double bond between the two carbon atoms to a single bond.

[0023] The surface layer of the amorphous carbon film AC is oxidized and vaporized by a chemical reaction with ozone molecules or the like and separates from the amorphous carbon film AC. In some cases, the heat of the substrate W vaporizes the oxidized amorphous carbon film AC. The gas generated by the vaporization of the amorphous carbon film AC such as carbon dioxide may be removed from the accommodation space SP1 by discharging the gas from the accommodation space SP1. As shown in FIG. 1C, in this way, the surface layer of the amorphous carbon film AC is removed and the volume of the amorphous carbon film AC decreases.

[0024] As shown in FIG. 1C, ozone molecules contained in ozone gas change not only into radicals such as oxygen radicals but also into oxygen molecules. Oxygen molecules may be generated by a chemical reaction between the radicals and the amorphous carbon film AC. When the surface of the amorphous carbon film AC is etched, a new surface of the amorphous carbon film AC is exposed, and this new surface is etched. By continuously repeating this phenomenon, the surfaces of the amorphous carbon film AC are successively replaced. Oxygen molecules contained in the gas in the accommodation space SP1 come into contact with the surface of the amorphous carbon film AC exposed by the etching of the amorphous carbon film AC.

[0025] When the supply of ozone gas to the amorphous carbon film AC is started, the concentration of oxidants such as ozone molecules and radicals is high and the concentration of oxygen is low. As the etching amount of the amorphous carbon film AC increases, at least one of a decrease in the concentration of the oxidant and an increase in the concentration of oxygen occurs. Therefore, the relative concentration of oxygen increases. When the etching amount of the amorphous carbon film AC reaches a certain value, the etching rate of the amorphous carbon film AC decreases to zero or near zero, and oxygen molecules contained in the gas in the accommodation space SP1 oxidize the surface layer of the amorphous carbon film AC. AC1 in FIG. 1C represents the oxide film AC1 of the amorphous carbon film AC.

[0026] At least a part of the amorphous carbon film AC oxidized by oxygen molecules contained in the gas in the accommodation space SP1 remains in the amorphous carbon film AC without vaporizing. The amorphous carbon film AC oxidized by the oxygen molecules may contain at least one of double-bonded carbon atoms and oxygen atoms (C=O), single-bonded carbon atoms and oxygen atoms (C-O), and carbon atoms and hydroxy groups (C-O-H) bonded thereto, or may contain other than these.

[0027] When oxygen molecules contained in the gas within the accommodation space SP1 oxidize the surface layer of the amorphous carbon film AC, only the surface layer of the amorphous carbon film AC changes to an oxide of amorphous carbon, and the remaining portion of the amorphous carbon film AC does not change from amorphous carbon. Hereinafter, the surface layer of the amorphous carbon film AC that has changed to an oxide of amorphous carbon may be referred to as the oxide film AC1 of the amorphous carbon film AC, and the remaining portion of the amorphous carbon film AC that has not changed to an oxide of amorphous carbon may be referred to as the bulk AC2 of the amorphous carbon film AC.

[0028] After performing the ozone gas etching process, a sulfuric acid ozone etching process is performed to etch the amorphous carbon film AC by supplying SOM, which is sulfuric acid containing ozone, to the substrate W. The sulfuric acid ozone etching process may be performed after moving the substrate W on which the ozone gas etching process has been performed, or may be performed without moving the same substrate W. In other words, the chamber that accommodates the substrate W on which the sulfuric acid ozone etching process is performed may be different from the chamber that accommodates the substrate W on which the ozone gas etching process is performed, or may be the same.

[0029] When performing the sulfuric acid ozone etching process, as shown in FIG. 1D, while heating the substrate W horizontally disposed within the accommodation space SP1, SOM is supplied to the upper surface of the substrate W. While the sulfuric acid ozone etching process is being performed, the temperature of the substrate W may be maintained at a constant value higher than room temperature, or may be changed within a range higher than room temperature. The temperature of the substrate W (the maximum value when the temperature is changed) when the sulfuric acid ozone etching process is being performed may be equal to or different from the temperature of the substrate W (the maximum value when the temperature is changed) when the ozone gas etching process is being performed. The heating of the substrate W may be performed by a contact-type or non-contact-type heater, or may be performed by a contact-type heater and a non-contact-type heater.

[0030] SOM is sulfuric acid containing ozone, that is, sulfuric acid in which ozone gas, which is a dissolved gas, is dissolved. Unless otherwise specified, SOM means a liquid. The sulfuric acid used when producing SOM is concentrated sulfuric acid (an aqueous solution of sulfuric acid with a sulfuric acid concentration of 90% or more). If there is no hindrance to the etching of the amorphous carbon film AC, SOM may be produced using an aqueous solution of sulfuric acid with a lower sulfuric acid concentration than concentrated sulfuric acid. Hereinafter, unless otherwise specified, sulfuric acid means an aqueous solution of sulfuric acid.

[0031] SOM is supplied to the entire upper surface of the substrate W. Accordingly, a liquid film of SOM that covers the entire upper surface of the substrate W is formed. When supplying SOM to the upper surface of the substrate W, SOM may be supplied while keeping the substrate W stationary, or SOM may be supplied while rotating the substrate W around a vertical axis passing through the central portion of the substrate W. As long as the entire upper surface of the substrate W is maintained in a state covered with the liquid film of SOM, SOM may be continuously added to the upper surface of the substrate W while scattering SOM from the outer periphery of the substrate W, or SOM may be stagnated on the upper surface of the substrate W while stopping the addition of SOM to the substrate W. In the latter case, the substrate W may be stationary or rotated at a low speed in a state where the entire upper surface of the substrate W is covered with SOM or sulfuric acid.

[0032] The ozone gas, which is a dissolved gas, may be dissolved in the sulfuric acid before contacting the substrate W, or may be dissolved in the sulfuric acid contacting the substrate W. FIG. 1D shows an example of the latter. In this example, while covering the entire upper surface of the substrate W with a liquid film of sulfuric acid, the accommodation space SP1 is filled with ozone gas. The ozone gas contained in the gas in the accommodation space SP1 diffuses from the surface of the liquid film of sulfuric acid contacting the upper surface of the substrate W into the inside of the same liquid film and dissolves in the sulfuric acid. Thereby, SOM is supplied to the upper surface of the substrate W.

[0033] The supply of ozone gas to the accommodation space SP1 may start simultaneously with the start of the supply of sulfuric acid to the substrate W, or may start before or after the start of the supply of sulfuric acid to the substrate W. The same applies to the timing of starting the heating of the substrate W. The supply of ozone gas to the accommodation space SP1 may start simultaneously with the start of the heating of the substrate W, or may start before or after the start of the heating of the substrate W. The supply of ozone gas to the accommodation space SP1 may be performed after or while discharging the gas in the accommodation space SP1.

[0034] The ozone gas as the etching gas may be dissolved in the sulfuric acid in contact with the substrate W, or another ozone gas different from the etching gas may be dissolved in the sulfuric acid in contact with the substrate W. In the latter case, after discharging the ozone gas as the etching gas from the accommodation space SP1, the ozone gas as the dissolution gas may be supplied to the accommodation space SP1. In this case, a gas containing no or almost no ozone, such as an inert gas or air, may be supplied to the accommodation space SP1 after discharging the ozone gas as the etching gas from the accommodation space SP1 and before supplying the ozone gas as the dissolution gas to the accommodation space SP1.

[0035] As shown in Chemical Formula 1, the sulfuric acid contained in the SOM dissociates into hydrogen ions and hydrogen sulfate ions. The SOM contains not only sulfuric acid but also ozone molecules. As shown in Chemical Formula 2, the hydrogen sulfate ions and ozone molecules in the SOM react with each other to generate water and peroxydisulfate ions. Since the substrate W is being heated, thermal energy is added to the peroxydisulfate ions in the SOM. As a result, as shown in Chemical Formula 3, the peroxydisulfate ions change into sulfate ion radicals (also called sulfuric acid radicals). In addition to or instead of heating the substrate W, the peroxydisulfate ions may be changed into sulfate ion radicals by irradiating light such as ultraviolet light on the SOM in contact with the substrate W.

[0036]

Chemical Formula

[0037] [Chemistry]

[0038] [Chemistry] The SOM in contact with the substrate W contains not only ozone molecules but also radicals such as oxygen radicals. The SOM in contact with the substrate W further contains the aforementioned peroxydisulfate ions and sulfate radicals. When the surface layer of the amorphous carbon film AC changes to the oxide film AC1 of the amorphous carbon film AC during the ozone gas etching process, the oxidizing agents in the SOM such as sulfate radicals decompose the oxide film AC1 of the amorphous carbon film AC and dissolve it in the SOM. As a result, as shown in Fig. 1E, the oxide film AC1 of the amorphous carbon film AC is removed, and a part of the bulk AC2 of the amorphous carbon film AC, that is, the part of the amorphous carbon film AC that has not changed to an oxide of the amorphous carbon film AC, is exposed. Hereinafter, the bulk AC2 of the amorphous carbon film AC is simply referred to as the amorphous carbon film AC.

[0039] As shown in Fig. 1F, ozone molecules, oxygen radicals, etc. in the SOM oxidize the surface layer of the amorphous carbon film AC. The oxidized amorphous carbon film AC dissolves in the SOM. As a result, the surface of the amorphous carbon film AC is etched. When the surface of the amorphous carbon film AC is etched, a new surface of the amorphous carbon film AC is exposed, and this new surface is etched. By continuously repeating this phenomenon, the surfaces of the amorphous carbon film AC are successively replaced. In this way, the surface layer of the amorphous carbon film AC is removed, and the volume of the amorphous carbon film AC decreases.

[0040] The etching rate of the amorphous carbon film AC in the ozone gas etching process is higher than that of the amorphous carbon film AC in the sulfuric acid ozone etching process. If the etching amount of the amorphous carbon film AC in the ozone gas etching process is larger than that of the amorphous carbon film AC in the sulfuric acid ozone etching process, the etching time in the ozone gas etching process may be equal to or different from the etching time in the sulfuric acid ozone etching process.

[0041] After etching the amorphous carbon film AC by SOM, the SOM is rinsed away with a rinse liquid such as pure water (deionized water: DIW) (step S3 in FIG. 2), and the substrate W is dried (step S4 in FIG. 2). When filling the accommodation space SP1 with ozone gas, the rinse liquid may be supplied to the substrate W while discharging the ozone gas from the accommodation space SP1, or the rinse liquid may be supplied to the substrate W before or after discharging the ozone gas from the accommodation space SP1. After supplying the rinse liquid to the entire upper surface of the substrate W, the substrate W with the liquid such as the rinse liquid attached is dried. The method of drying the substrate W may be spin drying that removes the liquid from the substrate W by rotating the substrate W at high speed, or a method other than spin drying such as vacuum drying that evaporates the liquid in contact with the substrate W by reducing the air pressure in the accommodation space SP1.

[0042] After drying the substrate W, the processing of the substrate W may be terminated, or the steps from the ozone gas etching step (step S1 in FIG. 2) to the drying step (step S4 in FIG. 2) may be performed again. That is, one cycle including the ozone gas etching step, the sulfuric acid ozone etching step, the rinsing step, and the drying step may be performed multiple times (step S5 in FIG. 2). When the oxide film AC1 of the amorphous carbon film AC is formed, the etching rate of the amorphous carbon film AC in the ozone gas etching step decreases to zero or near it. By performing the sulfuric acid ozone etching step, the oxide film AC1 of the amorphous carbon film AC can be removed. Therefore, by performing the above-described cycle multiple times, the amorphous carbon film AC can be efficiently etched.

[0043] Next, a cross-section of the substrate W on which the amorphous carbon film AC is formed will be described.

[0044] FIG. 3A is a schematic view showing an example of a cross-section of the substrate W before etching the amorphous carbon film AC. FIG. 3B is a schematic view showing an example of a cross-section of the substrate W after etching the amorphous carbon film AC. In FIGS. 3A and 3B, the relative thicknesses of thin films such as the resist film 101 are not necessarily the same as the actual relative thicknesses.

[0045] The amorphous carbon film AC before being etched may be a thin film without recesses recessed from the surface of the amorphous carbon film AC, or a thin film with recesses recessed from the surface of the amorphous carbon film AC. FIG. 3A shows an example of the former. In the latter case, the recesses may or may not penetrate the amorphous carbon film AC in the thickness direction of the amorphous carbon film AC (the vertical direction of the paper surface in FIG. 3A). The recesses may be holes or grooves, or may be other than these.

[0046] The etching of the amorphous carbon film AC shown in FIGS. 1A to 1F may be uniform etching that uniformly etches the entire amorphous carbon film AC, or may be selective etching that etches only a part of the amorphous carbon film AC. The selective etching may be etching that forms a recess penetrating in the thickness direction of the amorphous carbon film AC in the amorphous carbon film AC, or may be etching that forms a recess not penetrating in the thickness direction of the amorphous carbon film AC in the amorphous carbon film AC. FIG. 3B shows an example of the former.

[0047] The substrate W shown in FIG. 3A includes a disk-shaped base material 107 such as a silicon wafer and a laminated film formed on the base material 107. The laminated film is, for example, a part constituting a memory cell array of a three-dimensional NAND type flash memory. The memory cell array is a part including a plurality of memory cells three-dimensionally arranged in three orthogonal directions.

[0048] The laminated film includes a plurality of pairs of silicon oxide films 106 and silicon nitride films 105 laminated in the thickness direction of the substrate W so that the silicon oxide films 106 and the silicon nitride films 105 alternate with each other. The laminated film further includes a silicon oxide film 104 formed on the plurality of pairs of silicon oxide films 106 and silicon nitride films 105, an amorphous carbon film AC formed on the silicon oxide film 104, a silicon oxynitride film 103 formed on the amorphous carbon film AC, an antireflection film 102 formed on the silicon oxynitride film 103, and a resist film 101 formed on the antireflection film 102.

[0049] The amorphous carbon film AC is etched using the patterns of the silicon oxynitride film 103, the antireflection film 102, and the resist film 101 as masks. That is, the silicon oxynitride film 103, the antireflection film 102, and the resist film 101 are masks that expose only the portions of the amorphous carbon film AC to be etched and cover the portions of the amorphous carbon film AC that should not be etched. A part of the amorphous carbon film AC is exposed at the bottom of the recess 108 that penetrates the silicon oxynitride film 103, etc. in the thickness direction. In the etching of the amorphous carbon film AC shown in FIGS. 1A to 1F, only the portions not covered by the masks such as the silicon oxynitride film 103 are etched, and a recess 109 is formed to expose the silicon oxide film 104.

[0050] Next, the substrate processing apparatus 1 for etching the amorphous carbon film AC shown in FIGS. 1A to 1F will be described.

[0051] FIG. 4A is a schematic plan view showing the layout of the substrate processing apparatus 1 according to an embodiment of the present invention. FIG. 4B is a schematic side view of the substrate processing apparatus 1. The substrate processing apparatus 1 is a single-wafer type apparatus that processes a disk-shaped substrate W such as a semiconductor wafer one by one. The substrate processing apparatus 1 includes a load port LP that holds a carrier CA for accommodating the substrate W, a plurality of processing units 2 that process the substrate W conveyed from the carrier CA on the load port LP with a processing fluid such as a processing liquid or a processing gas, a transfer system TS that transfers the substrate W between the carrier CA on the load port LP and the plurality of processing units 2, an outer wall 1a that forms a sealed space accommodating the plurality of processing units 2 and the transfer system TS, and a control device 3 that controls the substrate processing apparatus 1.

[0052] The plurality of processing units 2 form a plurality of towers TW. FIG. 4A shows an example in which four towers TW are formed. As shown in FIG. 4B, the plurality of processing units 2 included in one tower TW are stacked vertically. As shown in FIG. 4A, the plurality of towers TW form two columns extending in the depth direction of the substrate processing apparatus 1 (the left-right direction of the paper surface in FIG. 4A) in plan view. In plan view, the two columns face each other via the transfer path TP.

[0053] The plurality of processing units 2 may include an ozone gas etching unit 2A (see FIG. 5A) that performs an ozone gas etching process and a sulfuric acid ozone etching unit 2B (see FIG. 6A) that performs a sulfuric acid ozone etching process. Alternatively, at least one processing unit 2 may be a multi-etching unit 2C (see FIG. 7A) that performs both the ozone gas etching process and the sulfuric acid ozone etching process. The plurality of processing units 2 may include an ozone gas etching unit 2A, a sulfuric acid ozone etching unit 2B, and a multi-etching unit 2C.

[0054] The transfer system TS includes an index robot IR that transfers the substrate W between the carrier CA on the load port LP and the plurality of processing units 2, and a center robot CR that transfers the substrate W between the index robot IR and the plurality of processing units 2. The index robot IR is disposed between the load port LP and the center robot CR in plan view. The center robot CR is disposed on the transfer path TP.

[0055] The index robot IR includes one or more hands Hi that horizontally support the substrate W. The hand Hi is movable parallel to both the horizontal direction and the vertical direction. The hand Hi is rotatable about a vertical straight line. The hand Hi can carry the substrate W into and out of the carrier CA on any load port LP and can transfer the substrate W with the center robot CR.

[0056] The center robot CR includes one or more hands Hc that horizontally support the substrate W. The hand Hc is movable parallel to both the horizontal and vertical directions. The hand Hc is rotatable about a vertical straight line. The hand Hc can transfer the substrate W with the index robot IR and can carry the substrate W into and out of any processing unit 2.

[0057] The control device 3 controls the electrical and electronic devices provided in the substrate processing apparatus 1. The control device 3 includes at least one computer. The computer includes a memory 3m that stores information such as programs, and a CPU 3c (central processing unit) that controls the substrate processing apparatus 1 according to the programs stored in the memory 3m. By controlling the substrate processing apparatus 1, the control device 3 performs the conveyance and processing of the substrate W described below. In other words, the control device 3 is programmed to perform the conveyance and processing of the substrate W described below.

[0058] Hereinafter, the ozone gas etching unit 2A, the sulfuric acid ozone etching unit 2B, and the multi-etching unit 2C will be described. First, the ozone gas etching unit 2A will be described.

[0059] FIGS. 5A and 5B are schematic views showing a vertical cross section of the ozone gas etching unit 2A. The ozone gas etching unit 2A includes a chamber 41 that forms the internal space of the ozone gas etching unit 2A, a door 43 that opens and closes an entrance / exit 42 formed in the chamber 41, an oxidation unit 44o that supplies a processing gas such as ozone gas to the substrate W while heating the substrate W in the chamber 41, a cooling unit 44c that cools the substrate W heated by the oxidation unit 44o in the chamber 41, and a local transfer robot 45 that transfers the substrate W in the chamber 41.

[0060] The cooling unit 44c and the oxidation unit 44o are arranged inside the chamber 41. The cooling unit 44c is closer to the entrance / exit 42 than the oxidation unit 44o. The center robot CR (see Fig. 4A) takes in and out the substrate W through the entrance / exit 42 to / from the chamber 41. The local transfer robot 45 receives the substrate W from the center robot CR and delivers the substrate W to the center robot CR. The local transfer robot 45 further transfers the substrate W between the cooling unit 44c and the oxidation unit 44o.

[0061] The cooling unit 44c includes a cooling plate 46 for cooling the substrate W, a lift pin 47 that moves up and down through the cooling plate 46, and a pin lifting actuator 48 for moving the lift pin 47 up and down. The cooling plate 46 is provided with a cooling surface 46a on which the substrate W is placed. Inside the cooling plate 46, a refrigerant path (not shown) through which a refrigerant (typically cooling water) circulates is formed. The lift pin 47 moves up and down between an upper position where it supports the substrate W above the cooling surface 46a and a lower position where the tip of the lift pin 47 is located below the cooling surface 46a.

[0062] An actuator is a device that converts driving energy representing electrical, fluid, magnetic, thermal, or chemical energy into mechanical work, that is, the movement of a physical object. Actuators include electric motors (rotary motors), linear motors, air cylinders, and other devices. When the movement of the actuator is different from the movement of the object, a motion converter for converting the movement of the actuator into linear motion or rotation may be provided. For example, when the actuator is an electric motor and the object is to be moved linearly, the rotation of the electric motor may be converted into linear motion by a motion converter such as a ball screw and a ball nut.

[0063] The acidification unit 44o includes a hot plate 49 for heating the substrate W, an inner chamber 50 for housing the hot plate 49, a lift pin 54 that moves up and down through the hot plate 49, and a pin lifting actuator 55 for moving the lift pin 54 up and down. The hot plate 49 is an example of a substrate holder. The hot plate 49 has a heating surface 49a on which the substrate W is placed. A heating element 49b that generates heat by power supply is built into the hot plate 49. When the substrate W is placed on the heating surface 49a, the substrate W is surrounded by the outer periphery of the heating surface 49a in plan view.

[0064] The inner chamber 50 forms an accommodation space SP1. The inner chamber 50 includes a fixed housing 52 fixed to the chamber 41 and a hood 51 that moves up and down above the fixed housing 52. The hot plate 49 is disposed between the hood 51 and the fixed housing 52. The hood 51 includes a disc-shaped plate portion 51p horizontally held above the hot plate 49 and a cylindrical portion 51t extending downward from the outer peripheral portion of the plate portion 51p. The lower end of the cylindrical portion 51t faces the upper end of the fixed housing 52 vertically.

[0065] The acidification unit 44o includes a hood lifting actuator 53 for lifting and lowering the hood 51. The fixed housing 52 has an upwardly open opening 52a, and the hood 51 opens and closes this opening 52a. As shown in FIG. 5B, the hood 51 is moved up and down between a closed position (lower position) where a sealed accommodation space SP1 is formed between the hood 51 and the fixed housing 52 and an open position (upper position) where the lower end of the cylindrical portion 51t is separated upward from the upper end of the fixed housing 52. The lift pin 54 is moved up and down between an upper position where it supports the substrate W above the heating surface 49a and a lower position where the tip of the lift pin 54 is located below the heating surface 49a.

[0066] The oxidation unit 44o includes an ozone gas supply port 19a that supplies ozone gas to the accommodation space SP1. FIGS. 5A and 5B show an example in which the ozone gas supply port 19a opens on the lower surface of the plate portion 51p of the hood 51. The oxidation unit 44o further includes an ozone gas generator 19d that generates ozone gas to be supplied to the ozone gas supply port 19a, an ozone gas pipe 19b that guides the ozone gas generated by the ozone gas generator 19d toward the ozone gas supply port 19a, and an ozone gas valve 19c that opens and closes between an open state in which ozone gas flows from the ozone gas pipe 19b to the ozone gas supply port 19a and a closed state in which ozone gas does not flow from the ozone gas pipe 19b to the ozone gas supply port 19a.

[0067] The oxidation unit 44o further includes an exhaust port 21a that discharges the gas in the accommodation space SP1, and an exhaust pipe 21b that guides the gas flowing into the exhaust port 21a in a direction away from the accommodation space SP1. When the ozone gas valve 19c is opened, ozone gas flows out from the ozone gas supply port 19a and is supplied to the accommodation space SP1. If the supply of ozone gas continues, the accommodation space SP1 is filled with ozone gas. The supply of ozone gas to the accommodation space SP1 may be performed while discharging the gas in the accommodation space SP1 to the exhaust port 21a, or may be performed after discharging the gas in the accommodation space SP1 to the exhaust port 21a.

[0068] The oxidation unit 44o includes an inert gas pipe 20a that guides nitrogen gas, which is an example of an inert gas to be supplied to the accommodation space SP1, and an inert gas valve 20b that opens and closes between an open state in which nitrogen gas flows from the inert gas pipe 20a to the accommodation space SP1 and a closed state in which nitrogen gas does not flow from the inert gas pipe 20a to the accommodation space SP1. FIGS. 5A and 5B show an example in which the nitrogen gas in the inert gas pipe 20a is supplied to the accommodation space SP1 via the ozone gas supply port 19a. The nitrogen gas in the inert gas pipe 20a may be supplied to the accommodation space SP1 via a supply port different from the ozone gas supply port 19a.

[0069] The local transfer robot 45 is provided with a hand 45h that transfers the substrate W between the cooling unit 44c and the oxidation unit 44o. The hand 45h is configured to be able to transfer the substrate W to and from the lift pin 47 of the cooling unit 44c and to and from the lift pin 54 of the oxidation unit 44o. Thereby, the hand 45h can operate to receive the substrate W from the lift pin 47 of the cooling unit 44c and transfer the substrate W to the lift pin 54 of the oxidation unit 44o. Further, the hand 45h can operate to receive the substrate W from the lift pin 54 of the oxidation unit 44o and transfer the substrate W to the lift pin 47 of the cooling unit 44c.

[0070] When performing the ozone gas etching process, the door 43 is arranged at the open position where it opens the entrance / exit 42. In that state, the hand Hc of the center robot CR (see FIG. 4A) enters the chamber 41 and places the substrate W above the cooling plate 46. Then, the lift pin 47 rises to the upper position and receives the substrate W from the hand Hc of the center robot CR. After that, the hand Hc of the center robot CR retreats outside the chamber 41.

[0071] Next, the hand 45h of the local transfer robot 45 receives the substrate W from the lift pin 47 and transfers the substrate W to the lift pin 54 of the oxidation unit 44o. At this time, the hood 51 is in the open position (upper position), and the lift pin 54 supports the received substrate W at the upper position. After the hand 45h retreats from the inner chamber 50, the lift pin 54 descends to the lower position and places the substrate W on the heating surface 49a. On the other hand, the hood 51 descends to the closed position (lower position) to form a sealed accommodation space SP1 that encloses the hot plate 49. In this state, the ozone gas etching process for the substrate W is performed.

[0072] In the ozone gas etching process, while supplying the ozone gas flowing out from the ozone gas supply port 19a to the substrate W on the hot plate 49, the substrate W is heated by the hot plate 49. Specifically, when the lift pin 54 places the substrate W received from the hand 45h of the local transfer robot 45 on the heating surface 49a of the hot plate 49, the heating of the substrate W by the hot plate 49 is started. After the hood 51 is arranged at the closed position (lower position), the ozone gas is supplied from the ozone gas supply port 19a to the accommodation space SP1, that is, the internal space of the inner chamber 50, and the gas in the accommodation space SP1 is discharged through the exhaust port 21a. Thereby, the ozone gas fills the accommodation space SP1 and is supplied to the substrate W on the hot plate 49. After performing the ozone gas etching process, the gas in the accommodation space SP1 such as ozone gas is discharged through the exhaust port 21a, and the accommodation space SP1 is filled with a gas other than ozone gas such as an inert gas.

[0073] When the ozone gas etching process is completed, the hood 51 rises to the open position (upper position) and the inner chamber 50 is opened. Further, the lift pin 54 rises to the upper position and pushes up the substrate W above the heating surface 49a. In that state, the hand 45h of the local transfer robot 45 receives the substrate W from the lift pin 54 and transfers the substrate W to the lift pin 47 of the cooling unit 44c. The lift pin 47 supports the received substrate W at the upper position. Waiting for the retraction of the hand 45h, the lift pin 47 descends to the lower position, whereby the substrate W is placed on the cooling surface 46a of the cooling plate 46. Thereby, the substrate W is cooled.

[0074] When the cooling of the substrate W is completed, the lift pin 47 rises to the upper position, thereby pushing up the substrate W above the cooling surface 46a. In that state, the door 43 is opened, the hand Hc of the center robot CR enters the chamber 41, and is arranged below the substrate W supported by the lift pin 47 at the upper position. In that state, when the lift pin 47 descends, the substrate W is passed to the hand Hc of the center robot CR. The hand Hc holding the substrate W retracts outside the chamber 41, and then the door 43 closes the entrance 42.

[0075] Next, the sulfuric acid ozone etching unit 2B that performs the sulfuric acid ozone etching process will be described.

[0076] FIGS. 6A and 6B are schematic views showing a vertical cross section of the sulfuric acid ozone etching unit 2B. The sulfuric acid ozone etching unit 2B includes a chamber 22 that forms an accommodation space SP1. The chamber 22 includes a partition wall 23 that forms the accommodation space SP1 and a door 25 that opens and closes an entrance / exit 24 provided in the partition wall 23. An opening / closing actuator 26 moves the door 25 between an open position where the substrate W can pass through the entrance / exit 24 and a closed position where the entrance / exit 24 is closed by the door 25.

[0077] The sulfuric acid ozone etching unit 2B includes a spin chuck 27a that rotates around a vertical rotation axis A1 passing through the central portion of the substrate W while horizontally holding one substrate W in the accommodation space SP1. The spin chuck 27a includes an electric motor 27d that rotates the substrate W held by the spin chuck 27a in a horizontal posture around the rotation axis A1.

[0078] The spin chuck 27a may be a clamping chuck that brings a plurality of chuck pins 27b into contact with the end face of the substrate W, or may be a vacuum chuck that horizontally holds the substrate W by adsorbing the back surface (lower surface) of the substrate W, which is a non-device formation surface, to the upper surface of a spin base 27c. FIGS. 6A and 6B show the former example. When the spin chuck 27a is a clamping chuck, the plurality of chuck pins 27b correspond to a substrate holder. When the spin chuck 27a is a vacuum chuck, the spin base 27c corresponds to a substrate holder.

[0079] The sulfuric acid ozone etching unit 2B includes a sulfuric acid nozzle 28a that supplies sulfuric acid to the upper surface of the substrate W held by the spin chuck 27a, and a rinse liquid nozzle 29a that supplies a rinse liquid to the upper surface of the substrate W held by the spin chuck 27a. FIG. 6A shows an example in which the rinse liquid is pure water (DIW). The rinse liquid is not limited to pure water, and may be any of IPA (isopropyl alcohol), carbonated water, electrolyzed ion water, hydrogen water, ozone water, hydrochloric acid water with a dilution concentration (for example, about 10 to 100 ppm), and ammonium hydroxide with a dilution concentration (for example, about 10 to 100 ppm).

[0080] As shown in FIG. 6A, the sulfuric acid ozone etching unit 2B includes a sulfuric acid pipe 28b that guides sulfuric acid toward the sulfuric acid nozzle 28a, and a sulfuric acid valve 28c that opens and closes between an open state in which sulfuric acid flows from the sulfuric acid pipe 28b to the sulfuric acid nozzle 28a and a closed state in which sulfuric acid does not flow from the sulfuric acid pipe 28b to the sulfuric acid nozzle 28a. When the sulfuric acid valve 28c is opened, sulfuric acid is continuously discharged downward from the discharge port of the sulfuric acid nozzle 28a.

[0081] The sulfuric acid ozone etching unit 2B includes a rinse liquid pipe 29b that guides the rinse liquid toward the rinse liquid nozzle 29a, and a rinse liquid valve 29c that opens and closes between an open state in which the rinse liquid flows from the rinse liquid pipe 29b to the rinse liquid nozzle 29a and a closed state in which the rinse liquid does not flow from the rinse liquid pipe 29b to the rinse liquid nozzle 29a. When the rinse liquid valve 29c is opened, the rinse liquid is continuously discharged downward from the discharge port of the rinse liquid nozzle 29a.

[0082] The sulfuric acid nozzle 28a may be a scan nozzle that can move the collision position of the processing liquid with respect to the substrate W within the upper or lower surface of the substrate W, or may be a fixed nozzle that cannot move the collision position of the processing liquid with respect to the substrate W. The same applies to the rinse liquid nozzle 29a. FIG. 6A shows an example in which the sulfuric acid nozzle 28a is a scan nozzle and the rinse liquid nozzle 29a is a fixed nozzle.

[0083] The sulfuric acid nozzle 28a is connected to a nozzle actuator 28e that moves the sulfuric acid nozzle 28a in at least one of the vertical and horizontal directions. The sulfuric acid nozzle 28a extends downward from the tip of a horizontally extending nozzle arm 28d. The nozzle actuator 28e is connected to the sulfuric acid nozzle 28a via the nozzle arm 28d. The nozzle actuator 28e horizontally moves the sulfuric acid nozzle 28a between a processing position where sulfuric acid discharged from the sulfuric acid nozzle 28a is supplied to the upper surface of the substrate W and a standby position where the sulfuric acid nozzle 28a is positioned around the spin chuck 27a in plan view.

[0084] The sulfuric acid ozone etching unit 2B includes a cylindrical processing cup 30 that receives liquid scattered from the substrate W held by the spin chuck 27a. The processing cup 30 includes a plurality of guards 31 that receive liquid scattered outward from the substrate W, a plurality of cups 32 that receive liquid guided downward by the plurality of guards 31, and a cylindrical outer wall 33 that surrounds the plurality of guards 31 and the plurality of cups 32. FIG. 6A shows an example in which two guards 31 and two cups 32 are provided and one cup 32 is integral with one guard 31.

[0085] The sulfuric acid ozone etching unit 2B includes a guard lifting actuator 34 that individually raises and lowers the plurality of guards 31. The guard lifting actuator 34 positions the guard 31 at an arbitrary position within a range from an upper position to a lower position. The upper position is a position where the upper end of the guard 31 is disposed above the holding position where the substrate W held by the spin chuck 27a is disposed. The lower position is a position where the upper end of the guard 31 is disposed below the holding position. The upper end of the guard 31 surrounds the substrate W and the spin base 27c in plan view.

[0086] When the processing liquid is supplied to the substrate W while the spin chuck 27a is rotating, the processing liquid supplied to the substrate W is flung off from the substrate W. When the processing liquid is supplied to the substrate W, the upper ends of at least one guard 31 are disposed above the substrate W. Accordingly, the processing liquid such as the chemical liquid or the rinse liquid discharged from the substrate W is received by one of the guards 31 and guided to the cup 32 corresponding to this guard 31.

[0087] An exhaust port 21a is formed at the bottom of the chamber 22. The exhaust port 21a is connected to an exhaust facility via an exhaust pipe 21b. An ozone gas supply port 19a is formed at the upper part of the chamber 22. The ozone gas supply port 19a is connected to an ozone gas pipe 19b and an inert gas pipe 20a. The gas flowing out from the ozone gas supply port 19a is supplied into the chamber 22. Thereby, the gas supplied from the ozone gas supply port 19a such as ozone gas fills the inside of the chamber 22 and is supplied to the substrate W disposed in the chamber 22.

[0088] As shown in FIG. 6B, the sulfuric acid ozone etching unit 2B includes a lamp 35 which is an example of a heater for heating the substrate W held by the spin chuck 27a. The sulfuric acid ozone etching unit 2B includes a lamp actuator 35a that horizontally moves the lamp 35 between a processing position where the lamp 35 emits light toward the upper surface of the substrate W and a standby position where the lamp 35 is positioned around the spin chuck 27a in plan view. By rotating the substrate W by the spin chuck 27a while horizontally moving the lamp 35 by the lamp actuator 35a, the entire substrate W can be uniformly heated.

[0089] When performing the sulfuric acid ozone etching process, after the center robot CR (see Fig. 4A) places the substrate W on the spin chuck 27a, the hand Hc is moved outside the sulfuric acid ozone etching unit 2B through the entrance / exit 24. Then, the entrance / exit 24 is closed by the door 25. When the substrate W is placed on the spin chuck 27a, the spin chuck 27a holds the substrate W by a plurality of chuck pins 27b and rotates the substrate W by the electric motor 27d. The guard lifting actuator 34 raises at least one guard 31 from the lower position to the upper position.

[0090] After the substrate W is held by the spin chuck 27a, with the spin chuck 27a rotating, the sulfuric acid valve 28c is opened to start discharging sulfuric acid from the sulfuric acid nozzle 28a. Thereby, as shown in Fig. 6B, sulfuric acid is supplied to the entire upper surface of the substrate W. After the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid, the supply of new sulfuric acid to the substrate W is stopped, and a paddle process may be performed while keeping the substrate W stationary or rotating at a low speed (e.g., 30 rpm or less) to maintain the state where the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid.

[0091] After the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid, while exhausting the gas in the chamber 22 from the exhaust port 21a, ozone gas is supplied into the chamber 22 from the ozone gas supply port 19a. Further, while causing the lamp 35 to emit light in the state where the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid, the distance from the rotation axis A1 of the substrate W to the lamp 35 is changed. The ozone gas in the chamber 22 dissolves into the liquid film of sulfuric acid covering the entire upper surface of the substrate W. Thereby, SOM is supplied to the upper surface of the substrate W. Further, since the lamp 35 generates heat, the substrate W and SOM are uniformly heated. Thereby, the sulfuric acid ozone etching process is performed.

[0092] When the substrate W is stationary with the entire upper surface thereof covered with a liquid film of sulfuric acid, the sulfuric acid does not move or hardly moves with respect to the upper surface of the substrate W and stagnates on the upper surface of the substrate W. The same applies when the substrate W is rotated at a low speed with the entire upper surface thereof covered with a liquid film of sulfuric acid. Thereby, the state where the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid is maintained. Before or after the substrate W is stationary or rotated at a low speed, a film thickness reduction step of reducing the thickness of the liquid film may be performed in a state where the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid by increasing the rotation speed of the substrate W. By doing so, the time until ozone dissolved in sulfuric acid reaches the upper surface of the substrate W can be shortened, and the concentration of ozone in sulfuric acid can be increased.

[0093] When a predetermined time has elapsed since the supply of sulfuric acid was started, the gas in the chamber 22 such as ozone gas is exhausted through the exhaust port 21a, and a gas other than ozone gas such as an inert gas is supplied into the chamber 22 from the ozone gas supply port 19a. Further, the lamp 35 is stopped from emitting light. In this state, a rinsing step of supplying a rinsing liquid to the substrate W is performed. Specifically, when the sulfuric acid valve 28c is open, the sulfuric acid valve 28c is closed. With the spin chuck 27a rotating the substrate W and the entire upper surface of the substrate W covered with a liquid film of sulfuric acid, the rinsing liquid valve 29c is opened and the discharge of the rinsing liquid from the rinsing liquid nozzle 29a is started. Thereby, the rinsing liquid is supplied to the entire upper surface of the substrate W, and the SOM on the substrate W is washed away.

[0094] When a predetermined time has elapsed since the supply of the rinsing liquid was started, the rinsing liquid valve 29c is closed. Thereafter, a drying step of drying the substrate W by high-speed rotation of the substrate W is performed. Specifically, with the discharge of the rinsing liquid from the rinsing liquid nozzle 29a stopped, the electric motor 27d accelerates the substrate W in the rotation direction and rotates the substrate W at a high rotation speed (for example, several thousand rpm) higher than the rotation speed of the substrate W from the sulfuric acid ozone etching step to the rinsing step. Thereby, the liquid is removed from the substrate W and the substrate W is dried. When a predetermined time has elapsed since the high-speed rotation of the substrate W was started, the electric motor 27d stops rotating.

[0095] After the rotation of the substrate W stops, all the guards 31 are arranged at the lower positions. In this state, the entrance / exit 24 is opened, and the center robot CR causes the hand Hc to enter the sulfuric acid ozone etching unit 2B. The center robot CR supports the substrate W on the spin chuck 27a with the hand Hc by moving the hand Hc. Then, the center robot CR moves the hand Hc outside the sulfuric acid ozone etching unit 2B through the entrance / exit 24. Thereby, the substrate W is carried out from the sulfuric acid ozone etching unit 2B.

[0096] Next, the multi-etching unit 2C that performs both the ozone gas etching process and the sulfuric acid ozone etching process will be described.

[0097] FIGS. 7A and 7B are schematic views showing a vertical cross-section of the multi-etching unit 2C. The multi-etching unit 2C includes the chamber 22, the spin chuck 27a, the sulfuric acid nozzle 28a, the rinse liquid nozzle 29a, and the processing cup 30 shown in FIGS. 6A and 6B. As shown in FIGS. 7A and 7B, the multi-etching unit 2C further includes a hot plate 36 which is an example of a heater for heating the substrate W held by the spin chuck 27a, a hood 37 that forms an accommodation space SP1, and a hood actuator 37a that vertically moves the hood 37 between an accommodation position where the substrate W is arranged inside the hood 37 and a standby position where the substrate W is arranged outside the hood 37.

[0098] The hot plate 36 is arranged between the substrate W and the spin base 27c. The hot plate 36 includes a heating element (not shown) that generates Joule heat by energization and an outer case that houses the heating element. The heating element and the outer case are arranged below the substrate W. The heating element is connected to a wiring (not shown) that supplies power to the heating element. The temperature of the heating element is changed by the control device 3 (see FIG. 4A). When the control device 3 causes the heating element to generate heat, the entire substrate W is uniformly heated.

[0099] The outer case of the hot plate 36 includes a disc-shaped base portion disposed below the substrate W and a plurality of hemispherical protrusions protruding upward from the upper surface of the base portion. The upper surface of the base portion is parallel to the lower surface of the substrate W and has an outer diameter smaller than the diameter of the substrate W. The plurality of protrusions contact the lower surface of the substrate W at positions spaced upward from the upper surface of the base portion. The plurality of protrusions are arranged at a plurality of positions within the upper surface of the base portion so that the substrate W is horizontally supported. The substrate W is horizontally supported in a state where the lower surface of the substrate W is spaced upward from the upper surface of the base portion.

[0100] The hot plate 36 is horizontally supported by a support shaft 36s extending downward from the central portion of the hot plate 36. A plurality of chuck pins 27b are arranged around the hot plate 36. The center line of the hot plate 36 is arranged on the rotation axis A1 of the substrate W. The hot plate 36 does not rotate even when the spin chuck 27a rotates. The outer diameter of the hot plate 36 is smaller than the diameter of the substrate W.

[0101] The hot plate 36 is movable up and down with respect to the spin base 27c. The hot plate 36 is connected to a plate lifting actuator 36a via the support shaft 36s. The plate lifting actuator 36a vertically raises and lowers the hot plate 36 between an upper position and a lower position (the positions shown in FIGS. 7A and 7B). The upper position is a contact position where the hot plate 36 contacts the lower surface of the substrate W. The lower position is a proximity position where the hot plate 36 is disposed between the lower surface of the substrate W and the upper surface of the spin base 27c in a state where the hot plate 36 is separated from the substrate W.

[0102] The hot plate 36 is an example of a substrate holder. The plate lifting actuator 36a positions the hot plate 36 at an arbitrary position within the range from the upper position to the lower position. When the substrate W is supported by the plurality of chuck pins 27b and the hot plate 36 rises to the upper position with the gripping of the substrate W released, the plurality of protrusions of the hot plate 36 come into contact with the lower surface of the substrate W, and the substrate W is supported by the hot plate 36. Thereafter, the substrate W is lifted by the hot plate 36 and moves upward away from the plurality of chuck pins 27b. In this state, when the hot plate 36 descends to the lower position, the substrate W on the hot plate 36 is placed on the plurality of chuck pins 27b, and the hot plate 36 moves away downward from the substrate W. In this way, the substrate W is transferred between the plurality of chuck pins 27b and the hot plate 36.

[0103] The hood 37 is disposed inside the chamber 22. The hood 37 is disposed above the spin chuck 27a. The hood 37 includes a disk-shaped plate portion 37p held horizontally and a cylindrical portion 37t extending downward from the outer peripheral portion of the plate portion 37p. The space inside the cylindrical portion 37t corresponds to the accommodation space SP1. The center of the plate portion 37p is disposed on the rotation axis A1 of the substrate W. The inner diameter of the cylindrical portion 37t is larger than the outer diameter of the spin base 27c. The outer diameter of the cylindrical portion 37t is smaller than the inner diameter of the upper end of the guard 31.

[0104] When the hood actuator 37a positions the hood 37 at the accommodation position shown in FIG. 7B, the lower end of the cylindrical portion 37t of the hood 37 is disposed below the substrate W held by the spin chuck 27a, and the substrate W is surrounded by the cylindrical portion 37t. When the hood actuator 37a positions the hood 37 at the standby position shown in FIG. 7A, the lower end of the cylindrical portion 37t of the hood 37 is disposed above the substrate W held by the spin chuck 27a. The same applies when the hot plate 36 holds the substrate W instead of the spin chuck 27a. The scan nozzle such as the sulfuric acid nozzle 28a is horizontally movable between the processing position and the standby position with the hood 37 disposed at the standby position.

[0105] The ozone gas supply port 19a opens on the lower surface of the plate portion 37p of the hood 37. FIG. 7A shows an example in which a plurality of ozone gas supply ports 19a open on the lower surface of the plate portion 37p. In this example, the ozone gas pipe 19b and the inert gas pipe 20a are connected to the plurality of ozone gas supply ports 19a. The exhaust port 21a is disposed below the substrate W held by the spin chuck 27a. In the examples shown in FIGS. 7A and 7B, the exhaust port 21a opens on the inner peripheral surface of the cylindrical outer wall 33 of the processing cup 30.

[0106] When performing the ozone gas etching process, the hood 37 is in the accommodation position, and with the spin chuck 27a or the hot plate 36 holding the substrate W, ozone gas is discharged from the ozone gas supply port 19a, and the substrate W is heated by the hot plate 36. Thereby, the space between the substrate W and the hood 37 is filled with ozone gas. Thereafter, inert gas is discharged from the ozone gas supply port 19a. The ozone gas is discharged from between the substrate W and the hood 37 by the inert gas and is pushed out of the chamber 22 through the exhaust port 21a.

[0107] When performing the sulfuric acid ozone etching process, the hood 37 is moved to the standby position while the substrate W is held by the spin chuck 27a or the hot plate 36. When the substrate W is held by the spin chuck 27a, the spin chuck 27a may or may not be rotating. In this state, sulfuric acid is discharged from the sulfuric acid nozzle 28a. Thereby, a liquid film of sulfuric acid covering the entire upper surface of the substrate W is formed. Thereafter, the discharge of sulfuric acid from the sulfuric acid nozzle 28a is stopped, and the sulfuric acid nozzle 28a is retracted from between the substrate W and the hood 37.

[0108] After the sulfuric acid nozzle 28a has retracted from between the substrate W and the hood 37, the hood 37 is lowered from the standby position to the accommodation position. In this state, ozone gas is discharged from the ozone gas supply port 19a. When the hot plate 36 has stopped generating heat, the hot plate 36 is restarted to generate heat. In this way, ozone gas dissolves into the liquid film of sulfuric acid covering the entire upper surface of the substrate W, and SOM is supplied to the entire upper surface of the substrate W.

[0109] After SOM has been supplied to the entire upper surface of the substrate W, an inert gas is discharged from the ozone gas supply port 19a, and the ozone gas is discharged from between the substrate W and the hood 37. When the substrate W is held by the hot plate 36, the substrate W is moved to the plurality of chuck pins 27b, and the substrate W is rotated by the spin chuck 27a. In this state, a rinse liquid is discharged from the rinse liquid nozzle 29a shown in FIG. 7A to wash away the SOM adhering to the substrate W. Then, the liquid is removed from the substrate W by rotating the substrate W at a high speed by the spin chuck 27a. Thereby, the substrate W is dried.

[0110] Next, the effects of the present embodiment will be described.

[0111] In the present embodiment, ozone gas, which is an etching gas, is supplied to the amorphous carbon film AC. Thereby, the amorphous carbon film AC can be etched without wetting the surface of the substrate W, which is the device formation surface. Further, since ozone gas is supplied to the amorphous carbon film AC while heating the substrate W, the etching rate of the amorphous carbon film AC can be increased. After ozone gas, which is an etching gas, is supplied to the amorphous carbon film AC, ozone-containing sulfuric acid, which is an etching liquid, that is, sulfuric acid in which ozone gas, which is a dissolved gas, is dissolved is supplied to the amorphous carbon film AC. Thereby, the amorphous carbon film AC can be further etched.

[0112] When supplying ozone-containing sulfuric acid, the etching rate of the amorphous carbon film AC is lower than that of the amorphous carbon film AC when supplying ozone gas. Therefore, the etching rate can be increased as compared with the case where the ozone gas etching step is not performed. Further, the total etching amount of the amorphous carbon film AC (the sum of the etching amount of the amorphous carbon film AC in the ozone gas etching step and the etching amount of the amorphous carbon film AC in the sulfuric acid-ozone etching step) can be easily and precisely adjusted as compared with the case where the sulfuric acid-ozone etching step is performed before the ozone gas etching step. In addition, the environmental load can be reduced as compared with the case where SPM (Sulfuric acid-Hydrogen Peroxide Mixture) is used instead of ozone-containing sulfuric acid.

[0113] In this embodiment, while heating the substrate W, ozone-containing sulfuric acid is supplied to the substrate W. Thereby, the ozone-containing sulfuric acid can be heated. The ozone-containing sulfuric acid generates peroxydisulfate ions in the ozone-containing sulfuric acid. The peroxydisulfate ions change into sulfate ion radicals having a strong oxidizing power. By applying thermal energy to the ozone-containing sulfuric acid, the change into sulfate ion radicals can be promoted. Thereby, the etching rate of the amorphous carbon film AC when supplying ozone-containing sulfuric acid can be increased.

[0114] In this embodiment, by supplying ozone gas as an etching gas to the substrate W, the surface of the amorphous carbon film AC is continuously removed. The ozone molecules contained in the ozone gas change not only into radicals such as oxygen radicals but also into oxygen molecules. Oxygen molecules may be generated by the chemical reaction between the radicals and the amorphous carbon film AC. The oxygen molecules form an oxide film AC1 of the amorphous carbon film AC on the surface layer of the amorphous carbon film AC by oxidizing the surface of the amorphous carbon film AC exposed by the etching of the amorphous carbon film AC. Ozone-containing sulfuric acid containing sulfate ions etches not only the amorphous carbon film AC but also the oxide film AC1 of the amorphous carbon film AC. Therefore, even when the oxide film AC1 of the amorphous carbon film AC is formed, the amorphous carbon film AC can be etched with ozone-containing sulfuric acid.

[0115] In this embodiment, one cycle including an ozone gas etching step and a sulfuric acid ozone etching step is performed multiple times. That is, after supplying ozone gas as an etching gas to the substrate W, ozone-containing sulfuric acid as an etching solution is supplied to the substrate W. Thereafter, ozone gas as an etching gas is supplied to the substrate W, and ozone-containing sulfuric acid as an etching solution is supplied to the substrate W. The oxide film AC1 of the amorphous carbon film AC may reduce the etching rate of the amorphous carbon film AC in the ozone gas etching step. By performing the above cycle multiple times, the oxide film AC1 of the amorphous carbon film AC can be removed, and such a decrease in the etching rate can be prevented.

[0116] In this embodiment, the substrate W is horizontally held so that the surface of the substrate W faces upward, and the accommodation space SP1 in which the substrate W is disposed is filled with ozone gas. In this state, sulfuric acid is discharged toward the surface of the substrate W. Thereby, a liquid film of sulfuric acid covering the entire surface of the substrate W is formed. The ozone gas in the accommodation position dissolves in the liquid film of sulfuric acid. Thereby, a liquid film of ozone-containing sulfuric acid covering the entire surface of the substrate W is formed. Further, since ozone gas is dissolved not in the sulfuric acid before contacting the substrate W but in the sulfuric acid contacting the substrate W, the time until an oxidizing agent such as an ozone molecule reaches the amorphous carbon film AC can be shortened.

[0117] In this embodiment, while the ozone-containing sulfuric acid is stagnated on the surface of the substrate W, the ozone-containing sulfuric acid is supplied to the entire surface of the substrate W. In other words, the ozone-containing sulfuric acid is supplied to the entire surface of the substrate W without discharging or hardly discharging the ozone-containing sulfuric acid from the substrate W. The ozone-containing sulfuric acid generates oxidizing agents such as peroxydisulfate ions and sulfate radicals. If the ozone-containing sulfuric acid is discharged from the substrate W, such oxidizing agents may be discharged from the substrate W before reacting with the amorphous carbon film AC. By stagnating the ozone-containing sulfuric acid on the surface of the substrate W, the oxidizing agent discharged from the substrate W before reacting with the amorphous carbon film AC can be reduced.

[0118] Next, another embodiment will be described.

[0119] The supply of ozone gas to the substrate W may be stopped before the oxide film AC1 of the amorphous carbon film AC is formed in the ozone gas etching process.

[0120] In the sulfuric acid ozone etching process, the ozone-containing sulfuric acid may be supplied to the substrate W without heating the substrate W.

[0121] Instead of dissolving ozone gas in sulfuric acid that contacts the substrate W, sulfuric acid in which ozone gas is dissolved may be supplied to the substrate W before contacting the substrate W. For example, ozone gas may be dissolved in sulfuric acid at any position on the path through which sulfuric acid passes from the tank storing sulfuric acid to the substrate W.

[0122] In the sulfuric acid ozone etching process, instead of maintaining a state in which the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid while stopping the supply of new sulfuric acid to the substrate W, a state in which the entire upper surface of the substrate W is covered with a liquid film of sulfuric acid may be maintained while adding new sulfuric acid to the upper surface of the substrate W. This is the same when discharging SOM corresponding to ozone-containing sulfuric acid toward the substrate W.

[0123] The substrate processing apparatus 1 is not limited to an apparatus that processes a disk-shaped substrate W, and may be an apparatus that processes a polygonal substrate W.

[0124] Two or more of all the above-described configurations may be combined. Two or more of all the above-described steps may be combined.

[0125] Although the embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical content of the present invention, and the present invention should not be construed as being limited to these specific examples. The spirit and scope of the present invention are limited only by the appended claims.

Explanation of Reference Numerals

[0126] 1: Substrate processing apparatus, 2A: Ozone gas etching unit, 2B: Sulfuric acid ozone etching unit, 2C: Multi-etching unit, 19a: Ozone gas supply port, 19b: Ozone gas pipe, 20a: Inert gas pipe, 21a: Exhaust port, 27a: Spin chuck, 27b: Chuck pin, 27c: Spin base, 27d: Electric motor, 28a: Sulfuric acid nozzle, 29a: Rinse liquid nozzle, 35: Lamp, 36: Hot plate, 37: Hood, 37p: Plate part, 37t: Cylindrical part, 49: Hot plate, 49a: Heating surface, 49b: Heating element, 50: Inner chamber, 51: Hood, 51p: Plate part, 51t: Cylindrical part, 52: Fixed housing, 52a: Opening, 101: Resist film, 102: Anti-reflection film, 103: Silicon oxynitride film, 104: Silicon oxide film, 105: Silicon nitride film, 106: Silicon oxide film, 107: Substrate, 108: Concave part, 109: Concave part, A1: Axis of rotation, AC: Amorphous carbon film, AC1: Oxide film of amorphous carbon film, AC2: Bulk of amorphous carbon film, SP1: Accommodation space, W: Substrate

Claims

1. An ozone gas etching step of etching the amorphous carbon film in a state where the surface of the substrate is dry by supplying ozone gas, which is an etching gas, to the amorphous carbon film formed on the surface of the substrate while heating the substrate; A sulfuric acid ozone etching step of etching the amorphous carbon film by supplying ozone-containing sulfuric acid, which is sulfuric acid in which ozone gas, which is a dissolving gas, is dissolved, to the amorphous carbon film after supplying the ozone gas to the amorphous carbon film. A substrate processing method comprising:

2. The sulfuric acid ozone etching step includes a step of supplying the ozone-containing sulfuric acid to the amorphous carbon film while heating the substrate. The substrate processing method according to Claim 1.

3. The ozone gas etching step includes a step of forming an oxide film of the amorphous carbon film on the surface layer of the amorphous carbon film by oxidizing the surface of the amorphous carbon film exposed by etching the amorphous carbon film. The sulfuric acid ozone etching step includes a step of etching the oxide film of the amorphous carbon film by supplying the ozone-containing sulfuric acid to the amorphous carbon film. The substrate processing method according to Claim 2.

4. The substrate processing method according to Claim 3, wherein one cycle including the ozone gas etching step and the sulfuric acid ozone etching step is performed a plurality of times.

5. The sulfuric acid ozone etching step includes a step of forming a liquid film of the ozone-containing sulfuric acid that covers the entire surface of the substrate by discharging sulfuric acid toward the surface of the substrate in a state where the substrate is held horizontally so that the surface of the substrate faces upward and the accommodation space in which the substrate is disposed is filled with ozone gas. The substrate processing method according to any one of Claims 1 to 4.

6. The sulfuric acid ozone etching step includes a step of stagnating the ozone-containing sulfuric acid on the surface of the substrate while maintaining a state where the entire surface of the substrate is covered with the liquid film of the ozone-containing sulfuric acid. The substrate processing method according to Claim 5.

7. A heater for heating a substrate having an amorphous carbon film formed on its surface; An ozone gas supply port for etching the amorphous carbon film while the surface of the substrate is in a dry state by supplying ozone gas, which is an etching gas, to the amorphous carbon film formed on the surface of the substrate, A nozzle for etching the amorphous carbon film by supplying ozone-containing sulfuric acid, which is sulfuric acid in which ozone gas, which is a dissolving gas, is dissolved, to the amorphous carbon film formed on the surface of the substrate after supplying the ozone gas to the amorphous carbon film. A substrate processing apparatus including the nozzle.

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