Substrate processing method and substrate processing apparatus

Abstract

The invention relates to a substrate processing method and a substrate processing apparatus. The substrate processing method includes: an ozone gas etching step in which an amorphous carbon film (AC) formed on the surface of a substrate (W) is etched with the surface of the substrate (W) in a dry state by supplying an ozone gas as an etching gas to the amorphous carbon film (AC) while heating the substrate (W); and a sulfuric acid ozone etching step for etching the amorphous carbon film (AC) by supplying ozone gas to the amorphous carbon film (AC) and then supplying ozone-containing sulfuric acid, which is sulfuric acid in which the ozone gas as the dissolved gas is dissolved, to the amorphous carbon film (AC).

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus for processing a substrate. The substrate includes, for example, a semiconductor wafer, a substrate for an FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (electroluminescence) display device, a substrate for an optical disc, a substrate for a magnetic disk, a substrate for a magneto-optical disc, a substrate for a photomask, a ceramic substrate, a substrate for a solar cell, and the like. Background Art

[0002] JP 2023-34828 A discloses heating a substrate in a processing chamber filled with ozone gas with a liquid film of sulfuric acid formed on the main surface of the substrate. Paragraph 0008 of JP 2023-34828 A describes "rapidly and sufficiently removing an organic film such as a resist from the substrate".

[0003] Although JP 2023-34828 A describes an organic film such as a resist, there is no description of an organic film other than the resist.

[0004] At least one embodiment of the present invention provides a substrate processing method and a substrate processing apparatus capable of increasing the etching rate of an amorphous carbon film. Summary of the Invention

[0005] One embodiment of the present invention provides a substrate processing method including the following steps: an ozone gas etching step of supplying ozone gas as an etching gas to an amorphous carbon film formed on the surface of the substrate while heating the substrate, thereby etching the amorphous carbon film in a dry state on the surface of the substrate; and a sulfuric acid ozone etching step of supplying sulfuric acid containing ozone gas, which is ozone gas as a dissolved gas, to the amorphous carbon film after supplying the ozone gas to the amorphous carbon film, thereby etching the amorphous carbon film.

[0006] In the above embodiment, at least one of the following features may be added to the substrate processing method.

[0007] The sulfuric acid ozone etching step includes the step of supplying the sulfuric acid containing ozone gas to the amorphous carbon film while heating the substrate.

[0008] The ozone gas etching process includes the following steps: by oxidizing the surface of the amorphous carbon film exposed due to the etching of the amorphous carbon film, an oxide film of the amorphous carbon film is formed on the surface layer of the amorphous carbon film; the sulfuric acid ozone etching process includes the following steps: by supplying the ozone-containing sulfuric acid to the amorphous carbon film, the oxide film of the amorphous carbon film is etched.

[0009] The following one cycle is repeated multiple times, and the one cycle includes the ozone gas etching process and the sulfuric acid ozone etching process.

[0010] The sulfuric acid ozone etching process includes the following steps: while horizontally holding the substrate with the surface of the substrate facing upward and the accommodation space where the substrate is disposed being filled with ozone gas, sulfuric acid is sprayed toward the surface of the substrate, thereby forming a liquid film of the ozone-containing sulfuric acid covering the entire area of the surface of the substrate.

[0011] The sulfuric acid ozone etching process includes the following steps: while maintaining the state where the entire area of the surface of the substrate is covered with the liquid film of the ozone-containing sulfuric acid, the ozone-containing sulfuric acid is allowed to stay on the surface of the substrate.

[0012] 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 etching the amorphous carbon film on the surface of the substrate in a dry state by supplying ozone gas as an etching gas to the amorphous carbon film formed on the surface of the substrate; and a nozzle for supplying sulfuric acid containing ozone gas as a dissolved gas, i.e., ozone-containing sulfuric acid, to the amorphous carbon film formed on the surface of the substrate after supplying the ozone gas to the amorphous carbon film, thereby etching the amorphous carbon film. At least one feature of the features regarding the substrate processing method may be added to the substrate processing apparatus.

[0013] In the above embodiment, at least one feature of the following features may be added to the substrate processing apparatus.

[0014] The nozzle supplies the ozone-containing sulfuric acid to the amorphous carbon film while the heater heats the substrate.

[0015] The ozone gas supply port forms 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 due to the etching of the amorphous carbon film, and the nozzle etches the oxide film of the amorphous carbon film by supplying the ozone-containing sulfuric acid to the amorphous carbon film.

[0016] The ozone gas supply port and the nozzle repeat the following one cycle multiple times. The one cycle includes etching of the amorphous carbon film using the ozone gas and etching of the amorphous carbon film using the ozone-containing sulfuric acid.

[0017] The nozzle horizontally holds the substrate with the surface of the substrate facing upward, and in a state where the accommodation space for the substrate is filled with ozone gas, sprays sulfuric acid toward the surface of the substrate, thereby forming a liquid film of the ozone-containing sulfuric acid that covers the entire area of the surface of the substrate.

[0018] The nozzle keeps the ozone-containing sulfuric acid staying on the surface of the substrate while maintaining the state where the entire area of the surface of the substrate is covered with the liquid film of the ozone-containing sulfuric acid. Description of the Drawings

[0019] Figures 1A - 1F It is a schematic cross-sectional view of a substrate for explaining the etching of an amorphous carbon film according to an embodiment.

[0020] Figure 2 It is a process diagram for explaining the etching of an amorphous carbon film according to an embodiment.

[0021] Figures 3A - 3B It is a schematic diagram showing an example of the cross-section of the substrate before and after etching the amorphous carbon film.

[0022] Figure 4A It is a schematic top view showing the layout of a substrate processing apparatus according to an embodiment.

[0023] Figure 4B It is a schematic side view of the substrate processing apparatus.

[0024] Figure 5A It is a schematic diagram showing a vertical cross-section of the ozone gas etching unit.

[0025] Figure 5B It is a schematic diagram showing a vertical cross-section of the ozone gas etching unit.

[0026] Figure 6A It is a schematic diagram showing a vertical cross-section of the sulfuric acid-ozone etching unit.

[0027] Figure 6B It is a schematic diagram showing a vertical cross-section of the sulfuric acid-ozone etching unit.

[0028] Figure 7A It is a schematic diagram showing a vertical cross-section of the multiple etching unit.

[0029] Figure 7B It is a schematic diagram showing a vertical cross-section of the multiple etching unit. Detailed Embodiments

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0031] Figures 1A - 1F It is a schematic cross-sectional view of a substrate W for explaining the etching of an amorphous carbon film AC in an embodiment. Figure 2 It is a process chart for explaining the etching of an amorphous carbon film AC in an embodiment. The etching rate is equivalent to the etching amount per unit time, that is, the etching speed.

[0032] 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 contain atoms other than carbon atoms such as hydrogen atoms, or may not contain them. 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) or less and an sp3 structure of 20 to 50%, or may be amorphous carbon other than a-C.

[0033] When etching the amorphous carbon film AC exposed on the surface of the substrate W, the following processes are performed: an ozone gas etching process ( Figure 2 step S1), by supplying ozone gas as an etching gas to the substrate W, the amorphous carbon film AC is etched in a state where the substrate W is dried; and a sulfuric acid-ozone etching process ( Figure 2 step S2), by supplying SOM (Sulfuric acid and Ozone Mixture, sulfuric acid-ozone mixture) containing ozone sulfuric acid to the substrate W, the amorphous carbon film AC is etched.

[0034] When performing the ozone gas etching process, as Figure 1A shown, the substrate W is horizontally disposed in the accommodation space SP1 with the surface of the substrate W facing upward. In this state, while heating the substrate W, ozone gas as an etching gas is supplied to the upper surface of the substrate W. The accommodation space SP1 is a space formed by a physical object such as a partition wall. 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 also be an open space.

[0035] When performing an ozone gas etching process, the substrate W is heated at a temperature higher than room temperature (e.g., 20 to 30 °C). During the ozone gas etching process, the temperature of the substrate W can be maintained at a fixed value higher than room temperature, or can vary within a range higher than room temperature. The heating of the substrate W can be performed using a contact heater such as a hot plate that contacts the substrate W, or can be performed using a non-contact heater such as a lamp that does not contact the substrate W. For example, the substrate W can be heated while being kept horizontal by bringing the hot plate into contact with the lower surface of the substrate W. As long as the heated hot plate is brought close to the substrate W without bringing the hot plate into contact with the substrate W, the substrate W can be heated. Therefore, the hot plate can also be an example of a non-contact heater.

[0036] As Figure 1A shown, in the ozone gas etching process, the ozone gas is filled into the accommodation space SP1 so that the ozone gas contacts the upper surface of the substrate W. When the ozone gas contacts the upper surface of the substrate W, the ozone gas can be supplied while keeping the substrate W stationary, or the ozone gas can be supplied while rotating the substrate W around a vertical rotation axis passing through the central portion of the substrate W. The supply of the ozone gas to the accommodation space SP1 can be started simultaneously with the start of heating the substrate W, or can be started before or after the start of heating the substrate W. The supply of the ozone gas to the accommodation space SP1 can be performed after discharging the gas in the accommodation space SP1 or while discharging.

[0037] The ozone gas is a gas having an ozone concentration higher than the ozone concentration in the atmosphere (e.g., 0.005 ppm). The ozone molecules contained in the ozone gas oxidize the amorphous carbon film AC exposed on the surface of the substrate W. As Figure 1B shown, the ozone molecules contained in the ozone gas change into oxygen radicals and other oxygen atom-containing radicals. Such radicals also oxidize the amorphous carbon film AC. When two carbon atoms contained in the amorphous carbon film AC form a double bond, the oxidation may include an oxidative cleavage reaction in which the double bond of the two carbon atoms changes into a single bond.

[0038] The surface layer of the amorphous carbon film AC is oxidized and vaporized by a chemical reaction with ozone molecules or the like, and separated from the amorphous carbon film AC. There is also a case where the heat of the substrate W vaporizes the oxidized amorphous carbon film AC. Gases such as carbon dioxide generated by the vaporization of the amorphous carbon film AC can be removed from the accommodation space SP1 by discharging the gas from the accommodation space SP1. As Figure 1C shown, in this way, the surface layer of the amorphous carbon film AC is removed, and the volume of the amorphous carbon film AC decreases.

[0039] As Figure 1CAs shown, the ozone molecules contained in the ozone gas are not only changed into free radicals such as oxygen free radicals, but also changed into oxygen molecules. There is also a case where oxygen molecules are generated through the chemical reaction of such free radicals with the amorphous carbon film AC. If 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 surface of the amorphous carbon film AC is sequentially replaced. The oxygen molecules contained in the gas in the accommodation space SP1 come into contact with the surface of the amorphous carbon film AC exposed due to the etching of the amorphous carbon film AC.

[0040] When starting to supply ozone gas to the amorphous carbon film AC, the concentration of oxidants such as ozone molecules or free radicals is high, and the oxygen concentration is low. As the etching amount of the amorphous carbon film AC increases, at least one of the decrease in the oxidant concentration and the increase in the oxygen concentration 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 it, and the oxygen molecules contained in the gas in the accommodation space SP1 oxidize the surface layer of the amorphous carbon film AC. Figure 1C ACl in [description] represents the oxide film ACl of the amorphous carbon film AC.

[0041] At least a part of the amorphous carbon film AC oxidized by the oxygen molecules contained in the gas in the accommodation space SP1 remains in the amorphous carbon film AC without being vaporized. The amorphous carbon film AC oxidized by such oxygen molecules may contain at least one of carbon atoms and oxygen atoms forming a double bond (C=O), carbon atoms and oxygen atoms forming a single bond (C-O), and carbon atoms and hydroxyl groups bonded to the carbon atoms (C-O-H), and may also contain others in addition to these.

[0042] If the oxygen molecules contained in the gas in 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 into an amorphous carbon oxide, and the remaining part of the amorphous carbon film AC does not change from the amorphous carbon. Hereinafter, the surface layer of the amorphous carbon film AC that changes into an amorphous carbon oxide is sometimes referred to as the oxide film AC1 of the amorphous carbon film AC, and the remaining part of the amorphous carbon film AC that does not change into an amorphous carbon oxide is referred to as the bulk AC2 of the amorphous carbon film AC.

[0043] After performing the ozone gas etching process, a sulfuric acid ozone etching process is performed: the amorphous carbon film AC is etched by supplying SOM, which is sulfuric acid containing ozone, to the substrate W. The sulfuric acid ozone etching process can be performed after moving the substrate W that has undergone the ozone gas etching process, or can be performed without moving the substrate W. In other words, the chamber accommodating the substrate W for the sulfuric acid ozone etching process can be different from the chamber accommodating the substrate W for the ozone gas etching process, or can be the same.

[0044] When performing the sulfuric acid ozone etching process, as Figure 1D shown, while heating the substrate W horizontally disposed in the accommodation space SP1, sulfuric acid containing ozone (SOM) is supplied to the upper surface of the substrate W. During the sulfuric acid ozone etching process, the temperature of the substrate W can be maintained at a fixed value higher than room temperature, or can vary within a range higher than room temperature. The temperature of the substrate W during the sulfuric acid ozone etching process (the maximum value in the case of temperature variation) can be equal to or different from the temperature of the substrate W during the ozone gas etching process (the maximum value in the case of temperature variation). Heating of the substrate W can be performed using a contact type or non-contact type heater, or can be performed using a contact type heater and a non-contact type heater.

[0045] SOM is sulfuric acid containing ozone, that is, sulfuric acid in which ozone gas as a dissolved gas is dissolved. Unless otherwise specified, SOM refers to a liquid. The sulfuric acid used to produce SOM is concentrated sulfuric acid (an aqueous solution of sulfuric acid with a sulfuric acid concentration of 90% or more). As long as the etching of the amorphous carbon film AC is not hindered, an aqueous solution of sulfuric acid with a sulfuric acid concentration lower than that of concentrated sulfuric acid can also be used to produce SOM. Hereinafter, unless otherwise specified, sulfuric acid refers to an aqueous solution of sulfuric acid.

[0046] SOM is supplied to the entire area of the upper surface of the substrate W. Therefore, a liquid film of SOM covering the entire area of the upper surface of the substrate W is formed. When supplying SOM to the upper surface of the substrate W, SOM can be supplied while keeping the substrate W stationary, or SOM can be supplied while rotating the substrate W around a vertical rotation axis passing through the central portion of the substrate W. As long as the state where the entire area of the upper surface of the substrate W is covered with the liquid film of SOM is maintained, SOM can be continuously added to the upper surface of the substrate W while allowing SOM to scatter from the outer periphery of the substrate W, or SOM can be allowed to stay 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 can also be kept stationary or rotated at a low speed in a state where the entire area of the upper surface of the substrate W is covered with SOM or sulfuric acid.

[0047] The ozone gas as a dissolved gas can be dissolved in sulfuric acid before contacting the substrate W, or can be dissolved in sulfuric acid in contact with the substrate W. Figure 1D An example of the latter is shown. In this example, while the entire area of the upper surface of the substrate W is covered 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 in contact with the upper surface of the substrate W into the interior of the liquid film and is dissolved in sulfuric acid. Thereby, SOM is supplied to the upper surface of the substrate W.

[0048] 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 to heat 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 carried out after discharging the gas in the accommodation space SP1 or may be carried out while discharging.

[0049] It is possible to dissolve ozone gas as an etching gas in the sulfuric acid in contact with the substrate W, or it is possible to dissolve ozone gas different from the etching gas in the sulfuric acid in contact with the substrate W. In the latter case, as long as the ozone gas as an etching gas is discharged from the accommodation space SP1, the ozone gas as a dissolved gas may be supplied to the accommodation space SP1. In this case, it is also possible to supply a gas containing little or almost no ozone, such as an inert gas or air, to the accommodation space SP1 after discharging the ozone gas as an etching gas from the accommodation space SP1 and before supplying the ozone gas as a dissolved gas to the accommodation space SP1.

[0050] 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 heated, heat energy is applied to the peroxydisulfate ions in the SOM. As a result, as shown in Chemical Formula 3, the peroxydisulfate ions change into sulfate radicals (also called sulfuric acid radicals). In addition to or instead of heating the substrate W, it is also possible to change the peroxydisulfate ions into sulfate radicals by irradiating light such as ultraviolet rays to the SOM in contact with the substrate W.

[0051] [Chem. 1]

[0052]

[0053] [Chem. 2]

[0054] 2HSO 4 - +O 3 →O 2 +H 2 O+S 2 O 8 2-

[0055] [Chem. 3]

[0056] S 2 O 8 2- →2SO4 -·

[0057] The SOM in contact with the substrate W contains not only ozone molecules but also free radicals such as oxygen free radicals. The SOM in contact with the substrate W also contains the persulfate ions and sulfate ion radicals. When the ozone gas etching process is carried out, in the case where the surface layer of the amorphous carbon film AC changes to the oxide film AC1 of the amorphous carbon film AC, the oxidizing agents in the SOM such as sulfate ion radicals decompose the oxide film AC1 of the amorphous carbon film AC and dissolve it in the SOM. Thus, as Figure 1E shown, the oxide film AC1 of the amorphous carbon film AC is removed, and the bulk AC2 of the amorphous carbon film AC, that is, a part of the amorphous carbon film AC that has not changed to the oxide of the amorphous carbon film AC, is exposed. Hereinafter, the bulk AC2 of the amorphous carbon film AC will be simply referred to as the amorphous carbon film AC.

[0058] As Figure 1F shown, the ozone molecules or oxygen free radicals in the SOM oxidize the surface layer of the amorphous carbon film AC. The oxidized amorphous carbon film AC dissolves in the SOM. Thus, the surface of the amorphous carbon film AC is etched. If the surface of the amorphous carbon film AC is etched, then a new surface of the amorphous carbon film AC is exposed, and this new surface is etched. By continuously repeating this phenomenon, the surface of the amorphous carbon film AC is sequentially 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.

[0059] The etching rate of the amorphous carbon film AC in the ozone gas etching process is greater than the etching rate of the amorphous carbon film AC in the sulfuric acid ozone etching process. As long as the etching amount of the amorphous carbon film AC in the ozone gas etching process is more than the etching amount of the amorphous carbon film AC in the sulfuric acid ozone etching process, the etching time of the ozone gas etching process can be equal to or different from the etching time of the sulfuric acid ozone etching process.

[0060] After etching the amorphous carbon film AC using the SOM, a rinsing liquid such as pure water (deionized water: DIW (Deionized Water)) is used to rinse the SOM ( Figure 2 step S3), and the substrate W is dried ( Figure 2Step S4). When filling the accommodation space SP1 with ozone gas, the rinse liquid can be supplied to the substrate W while discharging the ozone gas from the accommodation space SP1, or the rinse liquid can 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 area of the upper surface of the substrate W, the substrate W with the attached liquid such as the rinse liquid is dried. The method of drying the substrate W can be spin drying in which the liquid is removed from the substrate W by rotating the substrate W at high speed, or other methods other than spin drying such as reduced pressure drying in which the liquid in contact with the substrate W is evaporated by reducing the air pressure in the accommodation space SP1.

[0061] After drying the substrate W, the processing of the substrate W can be terminated, or the ozone gas etching process ( Figure 2 Steps S1) to the drying process ( Figure 2 Step S4). That is, one cycle including the ozone gas etching process, the sulfuric acid ozone etching process, the rinsing process, and the drying process can be performed multiple times ( Figure 2 Step S5). When forming the oxide film AC1 of the amorphous carbon film AC, the etching rate of the amorphous carbon film AC in the ozone gas etching process decreases to zero or near it. As long as the sulfuric acid ozone etching process is performed, the oxide film AC1 of the amorphous carbon film AC can be removed. Therefore, by performing the above cycle multiple times, the amorphous carbon film AC can be etched efficiently.

[0062] Next, the cross-section of the substrate W on which the amorphous carbon film AC is formed will be described.

[0063] Figure 3A is a schematic diagram showing an example of the cross-section of the substrate W before etching the amorphous carbon film AC. Figure 3B is a schematic diagram showing an example of the cross-section of the substrate W after etching the amorphous carbon film AC. Figure 3A and Figure 3B In, the relative thickness of the thin film such as the resist film 101 does not necessarily match the actual relative thickness.

[0064] The amorphous carbon film AC before etching can 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. Figure 3A shows an example of the former. In the case of the latter, the recesses can penetrate the amorphous carbon film AC in the thickness direction of the amorphous carbon film AC ( Figure 3A the vertical direction of the paper surface of this figure), or may not penetrate. The recesses can be holes or grooves, or other than these.

[0065] Figures 1A - 1FThe etching of the amorphous carbon film AC shown may be uniform etching that uniformly etches the entire amorphous carbon film AC, or selective etching that etches only a part of the amorphous carbon film AC. The selective etching may be etching for forming a recess that penetrates in the thickness direction of the amorphous carbon film AC in the amorphous carbon film AC, or etching for forming a recess that does not penetrate in the thickness direction of the amorphous carbon film AC in the amorphous carbon film AC. Figure 3B An example showing the former is given.

[0066] Figure 3A The substrate W shown 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 of a memory cell array constituting a 3D NAND type flash memory. The memory cell array is a part that includes a plurality of memory cells three-dimensionally arranged in three orthogonal directions.

[0067] The laminated film includes a plurality of pairs of silicon oxide films 106 and silicon nitride films 105, which are laminated in the thickness direction of the substrate W in such a manner 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.

[0068] 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 portion of the amorphous carbon film AC to be etched and cover the portion of the amorphous carbon film AC not to be etched. A part of the amorphous carbon film AC is exposed at the bottom of a recess 108 that penetrates the silicon oxynitride film 103, etc. in the thickness direction. Figures 1A - 1F In the etching of the amorphous carbon film AC shown, only the portion of the silicon oxynitride film 103, etc. not covered by the mask is etched to form a recess 109 that exposes the silicon oxide film 104.

[0069] Next, an explanation is given of the substrate processing apparatus 1 that performs Figures 1A - 1F the etching of the amorphous carbon film AC shown.

[0070] Figure 4A It is a schematic top view showing the layout of the substrate processing apparatus 1 according to an embodiment. Figure 4BIt is a schematic side view of the substrate processing apparatus 1. The substrate processing apparatus 1 is a single-chamber apparatus that processes circular-plate-shaped substrates W such as semiconductor wafers one by one. The substrate processing apparatus 1 includes: a load port LP that holds and houses a carrier CA for holding the substrate W; a plurality of processing units 2 that process the substrate W transferred 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 housing the plurality of processing units 2 and the transfer system TS; and a control device 3 that controls the substrate processing apparatus 1.

[0071] The plurality of processing units 2 form a plurality of towers TW. Figure 4A An example in which four towers TW are formed is shown. As Figure 4B shown, the plurality of processing units 2 included in one tower TW are stacked vertically. As Figure 4A shown, the plurality of towers TW form two columns extending in the depth direction ( Figure 4A the left-right direction of the paper surface) of the substrate processing apparatus 1 in plan view. In plan view, the two columns face each other with a transfer path TP interposed therebetween.

[0072] The plurality of processing units 2 may also include an ozone gas etching unit 2A that performs an ozone gas etching process (see Figure 5A ), and a sulfuric acid ozone etching unit 2B that performs a sulfuric acid ozone etching process (see Figure 6A ). Alternatively, at least one processing unit 2 may be a multiple etching unit 2C that performs both an ozone gas etching process and a sulfuric acid ozone etching process (see Figure 7A ). The plurality of processing units 2 may also include an ozone gas etching unit 2A, a sulfuric acid ozone etching unit 2B, and a multiple etching unit 2C.

[0073] The transfer system TS includes: an indexing 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 indexing robot IR and the plurality of processing units 2. The indexing robot IR is arranged between the load port LP and the center robot CR in plan view. The center robot CR is arranged on the transfer path TP.

[0074] The indexing robot IR includes one or more manipulators Hi that horizontally support the substrate W. The manipulator Hi can move parallel in either the horizontal direction or the vertical direction. The manipulator Hi can rotate around a vertical line. The manipulator 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.

[0075] The central robot CR includes one or more manipulators Hc that horizontally support the substrate W. The manipulator Hc can move parallel in either the horizontal direction or the vertical direction. The manipulator Hc can rotate around a vertical line. The manipulator Hc can transfer the substrate W with the indexing robot IR, and can carry the substrate W into and out of any processing unit 2.

[0076] The control device 3 controls the electrical and electronic devices included in the substrate processing device 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 (central processing unit) 3c that controls the substrate processing device 1 according to the programs stored in the memory 3m. The control device 3 performs the transfer and processing of the substrate W described below by controlling the substrate processing device 1. In other words, the control device 3 is programmed to perform the transfer and processing of the substrate W described below.

[0077] Hereinafter, the ozone gas etching unit 2A, the sulfuric acid ozone etching unit 2B, and the multiple etching unit 2C will be described. First, the ozone gas etching unit 2A will be described.

[0078] Figure 5A and Figure 5B is a schematic vertical cross-sectional view showing 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 processing gases 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.

[0079] The cooling unit 44c and the oxidation unit 44o are arranged in the chamber 41. The cooling unit 44c is closer to the entrance / exit 42 than the oxidation unit 44o. The central robot CR (refer to Figure 4A ) picks up and places the substrate W in the chamber 41 via the entrance / exit 42. The local transfer robot 45 receives the substrate W from the central robot CR and delivers the substrate W to the central robot CR. The local transfer robot 45 also transfers the substrate W between the cooling unit 44c and the oxidation unit 44o.

[0080] 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 lift actuator 48 that moves the lift pin 47 up and down. The cooling plate 46 has a cooling surface 46a for placing the substrate W. 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 the substrate W is supported above the cooling surface 46a and a lower position where the front end of the lift pin 47 is located below the cooling surface 46a.

[0081] An actuator is a device that converts driving energy representing electrical, fluid, magnetic, thermal, or chemical energy into mechanical work, i.e., the movement of a physical object. Actuators include electric motors (rotary motors), linear motors, cylinders, and other devices. When the movement of the actuator is different from the movement of the object, a motion converter that converts the movement of the actuator into a linear motion or rotation can also be provided. For example, when the actuator is an electric motor and the object is to move linearly, a motion converter such as a ball screw and a ball nut can be used to convert the rotation of the electric motor into a linear motion.

[0082] The oxidation unit 44o includes: a heating plate 49 for heating the substrate W, an inner chamber 50 that houses the heating plate 49, a lift pin 54 that moves up and down through the heating plate 49, and a pin lift actuator 55 that moves the lift pin 54 up and down. The heating plate 49 is an example of a substrate holder. The heating plate 49 has a heating surface 49a for placing the substrate W. A heating element 49b that generates heat by supplying power is built into the heating 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 a top view.

[0083] The inner chamber 50 forms a housing space SP1. The inner chamber 50 includes: a fixed housing 52 fixed to the chamber 41, and a cover 51 that moves up and down above the fixed housing 52. The heating plate 49 is disposed between the cover 51 and the fixed housing 52. The cover 51 includes: a disc-shaped plate portion 51p that is horizontally held above the heating plate 49, and a cylindrical portion 51t that extends 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.

[0084] The oxidation unit 44o includes a cover lift actuator 53 that lifts and lowers the cover 51. The fixed housing 52 has an opening 52a that opens upward, and the cover 51 opens and closes the opening 52a. As Figure 5BAs shown, the cover 51 moves up and down between a closed position (lower position) where a sealed accommodation space SP1 is formed between the cover 51 and the fixed housing 52, and an open position (upper position) where the lower end of the cylindrical portion 51t moves upward away from the upper end of the fixed housing 52. The lifting pin 54 moves up and down between an upper position that supports the substrate W above the heating surface 49a and a lower position where the front end of the lifting pin 54 is located below the heating surface 49a.

[0085] The oxidation unit 44o includes an ozone gas supply port 19a that supplies ozone gas to the accommodation space SP1. Figure 5A and Figure 5B An example is shown in which the ozone gas supply port 19a opens on the lower surface of the plate portion 51p of the cover 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 in the direction of the ozone gas supply port 19a; and an ozone gas valve 19c that opens and closes between an open state where ozone gas flows from the ozone gas pipe 19b to the ozone gas supply port 19a and a closed state where ozone gas does not flow from the ozone gas pipe 19b to the ozone gas supply port 19a.

[0086] 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 ozone gas is continuously supplied, the accommodation space SP1 will be filled with ozone gas. The supply of ozone gas to the accommodation space SP1 can be carried out while discharging the gas in the accommodation space SP1 at the exhaust port 21a, or can be carried out after discharging the gas in the accommodation space SP1 at the exhaust port 21a.

[0087] The oxidation unit 44o includes: an inert gas pipe 20a that guides nitrogen, 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 where nitrogen flows from the inert gas pipe 20a to the accommodation space SP1 and a closed state where nitrogen does not flow from the inert gas pipe 20a to the accommodation space SP1. Figure 5A and Figure 5B An example is shown in which nitrogen in the inert gas pipe 20a is supplied to the accommodation space SP1 via the ozone gas supply port 19a. Nitrogen in the inert gas pipe 20a can also be supplied to the accommodation space SP1 via a supply port different from the ozone gas supply port 19a.

[0088] The local transfer robot 45 is provided with a robot hand 45h that transfers the substrate W between the cooling unit 44c and the oxidation unit 44o. The robot hand 45h is configured to be able to transfer the substrate W between the lifting pins 47 of the cooling unit 44c and the lifting pins 54 of the oxidation unit 44o. Thus, the robot hand 45h can operate in such a manner that it receives the substrate W from the lifting pins 47 of the cooling unit 44c and delivers the substrate W to the lifting pins 54 of the oxidation unit 44o. Further, the robot hand 45h can operate in such a manner that it receives the substrate W from the lifting pins 54 of the oxidation unit 44o and delivers the substrate W to the lifting pins 47 of the cooling unit 44c.

[0089] When performing the ozone gas etching process, the door 43 is disposed at the open position where the entrance / exit 42 is open. In this state, the robot hand Hc of the center robot CR (refer to Figure 4A ) enters the chamber 41 and disposes the substrate W above the cooling plate 46. Then, the lifting pins 47 rise to the upper position and receive the substrate W from the robot hand Hc of the center robot CR. Then, the robot hand Hc of the center robot CR retreats outside the chamber 41.

[0090] Next, the robot hand 45h of the local transfer robot 45 receives the substrate W from the lifting pins 47 and transfers the substrate W to the lifting pins 54 of the oxidation unit 44o. At this time, the cover 51 is at the open position (upper position), and the lifting pins 54 support the received substrate W at the upper position. After the robot hand 45h retreats from the inner chamber 50, the lifting pins 54 descend to the lower position and place the substrate W on the heating surface 49a. On the other hand, the cover 51 descends to the closed position (lower position) to form a sealed accommodation space SP1 that encloses the heating plate 49. In this state, the ozone gas etching process is performed on the substrate W.

[0091] During the ozone gas etching process, while supplying ozone gas flowing out from the ozone gas supply port 19a to the substrate W on the heating plate 49, the substrate W is heated by the heating plate 49. Specifically, when the lifting pins 54 place the substrate W received from the robot hand 45h of the local transfer robot 45 on the heating surface 49a of the heating plate 49, heating of the substrate W by the heating plate 49 is started. After the cover 51 is disposed at the closed position (lower position), 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. Thus, the ozone gas fills the accommodation space SP1 and is supplied to the substrate W on the heating plate 49. After the ozone gas etching process is performed, the gas in the accommodation space SP1 such as ozone gas is discharged through the exhaust port 21a, and a gas other than ozone gas such as an inert gas fills the accommodation space SP1.

[0092] When the ozone gas etching process is completed, the cover 51 rises to the open position (upper position), opening the inner chamber 50. Further, the lift pin 54 rises to the upper position, lifting the substrate W above the heating surface 49a. In this state, the robot 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 in the upper position. After waiting for the robot hand 45h to retract, the lift pin 47 descends to the lower position, thereby placing the substrate W on the cooling surface 46a of the cooling plate 46. Thereby, the substrate W is cooled.

[0093] When the cooling of the substrate W is completed, the lift pin 47 rises to the upper position, thereby lifting the substrate W above the cooling surface 46a. In this state, the door 43 is opened, and the robot hand Hc of the central robot CR enters the chamber 41 and is disposed below the substrate W supported by the lift pin 47 located in the upper position. In this state, by lowering the lift pin 47, the substrate W is delivered to the robot hand Hc of the central robot CR. The robot hand Hc holding the substrate W retracts outside the chamber 41, and then the door 43 closes the entrance / exit 42.

[0094] Next, the sulfuric acid ozone etching unit 2B that performs the sulfuric acid ozone etching process will be described.

[0095] Figure 6A and Figure 6B is a schematic vertical cross-sectional view showing the sulfuric acid ozone etching unit 2B. The sulfuric acid ozone etching unit 2B includes a chamber 22 that forms a housing space SP1. The chamber 22 includes a partition wall 23 that forms the housing space SP1 and a door 25 that opens and closes an entrance / exit 24 provided in the partition wall 23. The 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.

[0096] The sulfuric acid ozone etching unit 2B includes a rotary chuck 27a that rotates one substrate W horizontally in the housing space SP1 around a vertical rotation axis A1 passing through the central portion of the substrate W. The rotary chuck 27a includes an electric motor 27d that rotates the substrate W held in the rotary chuck 27a in a horizontal posture around the rotation axis A1.

[0097] The rotary chuck 27a may be a clamping chuck that brings a plurality of chuck pins 27b into contact with the end surface 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 the non-device formation surface, to the upper surface of the rotary base 27c. Figure 6A and Figure 6BAn example of the former is shown. When the rotary chuck 27a is a clamping chuck, the plurality of chuck pins 27b correspond to the substrate holder. When the rotary chuck 27a is a vacuum chuck, the rotary base 27c corresponds to the substrate holder.

[0098] 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 rotary chuck 27a; and a rinse liquid nozzle 29a that supplies a rinse liquid to the upper surface of the substrate W held by the rotary chuck 27a. Figure 6A An example where the rinse liquid is pure water (DIW) is shown. The rinse liquid is not limited to pure water and can be any one of IPA (isopropyl alcohol), carbonated water, electrolyzed ion water, hydrogen water, ozone water, hydrochloric acid water with a dilution concentration (e.g., around 10 to 100 ppm), and ammonium hydroxide with a dilution concentration (e.g., around 10 to 100 ppm).

[0099] As Figure 6A shown, the sulfuric acid ozone etching unit 2B includes: a sulfuric acid pipe 28b that guides sulfuric acid in the direction of the sulfuric acid nozzle 28a; and a sulfuric acid valve 28c that opens and closes between an open state where sulfuric acid flows from the sulfuric acid pipe 28b to the sulfuric acid nozzle 28a and a closed state where 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 continuously sprays downward from the discharge port of the sulfuric acid nozzle 28a.

[0100] The sulfuric acid ozone etching unit 2B includes: a rinse liquid pipe 29b that guides the rinse liquid in the direction of the rinse liquid nozzle 29a; and a rinse liquid valve 29c that opens and closes between an open state where the rinse liquid flows from the rinse liquid pipe 29b to the rinse liquid nozzle 29a and a closed state where 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 continuously sprays downward from the discharge port of the rinse liquid nozzle 29a.

[0101] The sulfuric acid nozzle 28a can be a scanning nozzle that can move the collision position of the processing liquid on the substrate W within the upper surface or the lower surface of the substrate W, or a fixed nozzle that cannot move the collision position of the processing liquid on the substrate W. The same applies to the rinse liquid nozzle 29a. Figure 6A An example where the sulfuric acid nozzle 28a is a scanning nozzle and the rinse liquid nozzle 29a is a fixed nozzle is shown.

[0102] 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 moves the sulfuric acid nozzle 28a horizontally between a processing position where sulfuric acid ejected 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 located around the rotary chuck 27a in plan view.

[0103] The sulfuric acid ozone etching unit 2B includes a cylindrical processing susceptor 30 that catches liquid scattered from the substrate W held by the rotary chuck 27a. The processing susceptor 30 includes: a plurality of protection baffles 31 that catch liquid scattered outward from the substrate W; a plurality of susceptors 32 that catch the liquid guided downward by the plurality of protection baffles 31; and a cylindrical outer wall 33 that surrounds the plurality of protection baffles 31 and the plurality of susceptors 32. Figure 6A An example is shown in which two protection baffles 31 and two susceptors 32 are provided, and one susceptor 32 is integrated with one protection baffle 31.

[0104] The sulfuric acid ozone etching unit 2B includes a protection baffle lifting actuator 34 that individually raises and lowers the plurality of protection baffles 31. The protection baffle lifting actuator 34 positions the protection baffle 31 at any position within a range from an upper position to a lower position. The upper position is a position where the upper end of the protection baffle 31 is disposed above the holding position of the substrate W held by the rotary chuck 27a. The lower position is a position where the upper end of the protection baffle 31 is disposed below the holding position. The upper end of the protection baffle 31 surrounds the substrate W and the rotary base 27c in plan view.

[0105] If the processing liquid is supplied to the substrate W while the rotary chuck 27a is rotating, the processing liquid supplied to the substrate W will be flung off from the substrate W. When the processing liquid is supplied to the substrate W, the upper end of at least one protection baffle 31 is disposed above the substrate W. Therefore, the processing liquid such as the chemical solution or the rinse liquid discharged from the substrate W is caught by any one of the protection baffles 31 and guided into the susceptor 32 corresponding to that protection baffle 31.

[0106] An exhaust port 21a is formed at the bottom of the chamber 22. The exhaust port 21a is connected to an exhaust device via an exhaust pipe 21b. An ozone gas supply port 19a is formed in 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 to the inside of 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.

[0107] As Figure 6B shown, the sulfuric acid ozone etching unit 2B includes a lamp 35, which is an example of a heater that heats the substrate W held by the rotary 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 located around the rotary chuck 27a in a plan view. By horizontally moving the lamp 35 using the lamp actuator 35a while rotating the substrate W using the rotary chuck 27a, the entire substrate W can be uniformly heated.

[0108] When performing the sulfuric acid ozone etching process, after the central robot CR (refer to Figure 4A ) places the substrate W on the rotary chuck 27a, the manipulator Hc moves out of the sulfuric acid ozone etching unit 2B through the access port 24. Then, the access port 24 is closed by the door 25. When the substrate W is placed on the rotary chuck 27a, the rotary chuck 27a holds the substrate W using a plurality of chuck pins 27b and rotates the substrate W using an electric motor 27d. The protective baffle lifting actuator 34 raises at least one protective baffle 31 from a lower position to an upper position.

[0109] After holding the substrate W on the rotary chuck 27a, with the rotary chuck 27a rotating, the sulfuric acid valve 28c is opened to cause the sulfuric acid nozzle 28a to start spraying sulfuric acid. Thus, as Figure 6B shown, sulfuric acid is supplied to the entire area of the upper surface of the substrate W. After the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid, it is also possible to stop supplying new sulfuric acid to the substrate W and perform a liquid covering process, that is, while keeping the substrate W stationary or rotating at a low speed (for example, 30 rpm or less), maintaining the state where the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid.

[0110] After the entire area of the 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, in a state where the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid, while causing the lamp 35 to emit light, the distance between the rotation axis A1 of the substrate W and the lamp 35 is changed. The ozone gas in the chamber 22 dissolves into the liquid film of sulfuric acid covering the entire area of the upper surface of the substrate W. Thus, 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. Thus, the sulfuric acid ozone etching process is performed.

[0111] If the substrate W is stationary in a state where the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid, the sulfuric acid does not move or hardly moves relative to the upper surface of the substrate W and stays on the upper surface of the substrate W. The same applies when the substrate W is rotated at a low speed in a state where the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid. Thus, the state where the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid is maintained. A film thickness reduction process can also be performed, that is, by increasing the rotation speed of the substrate W before or after the substrate W is stationary or rotated at a low speed, the thickness of the liquid film is reduced in a state where the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid. In this way, the time for ozone dissolved in sulfuric acid to reach the upper surface of the substrate W can be shortened, and the concentration of ozone in sulfuric acid can be increased.

[0112] If a specified time has elapsed since the start of supplying sulfuric acid, the gas in the chamber 22 such as ozone gas is discharged 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 process 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. In a state where the rotating chuck 27a rotates the substrate W and the entire area of the upper surface of the substrate W is covered with a liquid film of sulfuric acid, the rinsing liquid valve 29c is opened, and the rinsing liquid nozzle 29a starts to spray the rinsing liquid. Thus, the rinsing liquid is supplied to the entire area of the upper surface of the substrate W, and the SOM on the substrate W is rinsed.

[0113] If a specified time has elapsed since the start of supplying the rinsing liquid, the rinsing liquid valve 29c is closed. Then, a drying process is performed to dry the substrate W by high-speed rotation of the substrate W. Specifically, in a state where the rinsing liquid stops spraying from the rinsing liquid nozzle 29a, the electric motor 27d accelerates the substrate W in the rotation direction, and the substrate W is rotated at a high rotation speed (for example, several thousand rpm) higher than the rotation speed of the substrate W in the sulfuric acid ozone etching process to the rinsing process. Thus, the liquid is removed from the substrate W, and the substrate W is dried. If a specified time has elapsed since the substrate W started to rotate at a high speed, the electric motor 27d stops rotating.

[0114] After the substrate W stops rotating, all the protective baffles 3l are arranged at the lower positions. In this state, the entrance / exit 24 is opened, and the central robot CR makes the mechanical hand Hc enter the sulfuric acid ozone etching unit 2B. The central robot CR supports the substrate W on the rotating chuck 27a by moving the mechanical hand Hc. Then, the central robot CR moves the mechanical hand Hc out of the sulfuric acid ozone etching unit 2B through the entrance / exit 24. Thus, the substrate W is carried out of the sulfuric acid ozone etching unit 2B.

[0115] Next, the multiple etching unit 2C that performs both the ozone gas etching process and the sulfuric acid ozone etching process will be described.

[0116] Figure 7A and Figure 7B is a schematic diagram showing a vertical cross-section of the multiple etching unit 2C. The multiple etching unit 2C includes Figure 6A and Figure 6B the chamber 22, the rotary chuck 27a, the sulfuric acid nozzle 28a, the rinse liquid nozzle 29a, and the processing susceptor 30 shown. As Figure 7A and Figure 7B shown, the multiple etching unit 2C further includes: a heating plate 36, which is an example of a heater that heats the substrate W held by the rotary chuck 27a; a cover 37, which forms a housing space SP1; and a cover actuator 37a, which vertically moves the cover 37 between a housing position where the substrate W is disposed in the cover 37 and a standby position where the substrate W is disposed outside the cover 37.

[0117] The heating plate 36 is disposed between the substrate W and the rotary base 27c. The heating plate 36 includes a heating element (not shown) that generates Joule heat by being energized, and a housing that houses the heating element. The heating element and the housing are disposed 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 (refer to Figure 4A ). When the control device 3 causes the heating element to generate heat, the entire substrate W is uniformly heated.

[0118] The housing of the heating plate 36 includes: a disk-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 disposed at a plurality of positions within the upper surface of the base portion so as to horizontally support the substrate W. 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.

[0119] The heating plate 36 is horizontally supported by a mandrel 36s that extends downward from the central portion of the heating plate 36. A plurality of chuck pins 27b are disposed around the heating plate 36. The center line of the heating plate 36 is disposed on the rotation axis A1 of the substrate W. Even if the rotary chuck 27a rotates, the heating plate 36 does not rotate. The outer diameter of the heating plate 36 is smaller than the diameter of the substrate W.

[0120] The heating plate 36 can move up and down relative to the rotary base 27c. The heating plate 36 is connected to a plate lifting actuator 36a via the mandrel 36s. The plate lifting actuator 36a moves the heating plate 36 between an upper position and a lower position ( Figure 7A and Figure 7Bvertically move up and down between the positions shown. The upper position is the contact position where the heating plate 36 contacts the lower surface of the substrate W. The lower position is the proximity position where the heating plate 36 is disposed between the lower surface of the substrate W and the upper surface of the rotary base 27c in a state where the heating plate 36 is separated from the substrate W.

[0121] The heating plate 36 is an example of a substrate holder. The plate lifting actuator 36a positions the heating plate 36 at any position within the range from the upper position to the lower position. When the substrate W is supported by a plurality of chuck pins 27b and the holding of the substrate W is released, and the heating plate 36 rises to the upper position, the plurality of protrusions of the heating plate 36 contact the lower surface of the substrate W, and the substrate W is supported by the heating plate 36. Then, the substrate W is lifted by the heating plate 36 and moves upward away from the plurality of chuck pins 27b. In this state, when the heating plate 36 descends to the lower position, the substrate W on the heating plate 36 is located above the plurality of chuck pins 27b, and the heating plate 36 moves downward away from the substrate W. In this way, the substrate W is transferred between the plurality of chuck pins 27b and the heating plate 36.

[0122] The cover 37 is disposed in the chamber 22. The cover 37 is disposed above the rotary chuck 27a. The cover 37 includes: a disk-shaped plate portion 37p that is horizontally held, and a cylindrical portion 37t that extends downward from the outer peripheral portion of the plate portion 37p. The inner space of 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 rotary base 27c. The outer diameter of the cylindrical portion 37t is smaller than the inner diameter of the upper end of the protective baffle 31.

[0123] When the cover actuator 37a positions the cover 37 at the Figure 7B accommodation position shown, the lower end of the cylindrical portion 37t of the cover 37 is disposed below the substrate W held by the rotary chuck 27a, and the substrate W is surrounded by the cylindrical portion 37t. When the cover actuator 37a positions the cover 37 at the Figure 7A standby position shown, the lower end of the cylindrical portion 37t of the cover 37 is disposed above the substrate W held by the rotary chuck 27a. The same applies when the heating plate 36, rather than the rotary chuck 27a, holds the substrate W. The scanning nozzles such as the sulfuric acid nozzle 28a can horizontally move between the processing position and the standby position in a state where the cover 37 is disposed at the standby position.

[0124] The ozone gas supply port 19a opens on the lower surface of the plate portion 37p of the cover 37. Figure 7A An example showing that a plurality of ozone gas supply ports 19a open on the lower surface of the plate portion 37p is shown. 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 rotary chuck 27a. Figure 7A and Figure 7BIn the illustrated example, the exhaust port 21a opens on the inner circumferential surface of the cylindrical outer wall 33 of the processing susceptor 30.

[0125] When performing the ozone gas etching process, with the cover 37 in the accommodation position and the substrate W held by the rotary chuck 27a or the heating plate 36, the ozone gas supply port 19a ejects ozone gas, and the heating plate 36 heats the substrate W. Thereby, the space between the substrate W and the cover 37 is filled with ozone gas. Then, the ozone gas supply port 19a ejects an inert gas. The ozone gas is discharged from between the substrate W and the cover 37 due to the inert gas and is extruded outside the chamber 22 through the exhaust port 21a.

[0126] When performing the sulfuric acid ozone etching process, with the substrate W held by the rotary chuck 27a or the heating plate 36, the cover 37 is moved to the standby position. When the substrate W is held by the rotary chuck 27a, the rotary chuck 27a can rotate or not rotate. In this state, the sulfuric acid nozzle 28a ejects sulfuric acid. Thereby, a liquid film of sulfuric acid covering the entire area of the upper surface of the substrate W is formed. Then, the sulfuric acid nozzle 28a stops ejecting sulfuric acid, and the sulfuric acid nozzle 28a retracts from between the substrate W and the cover 37.

[0127] After the sulfuric acid nozzle 28a retracts from between the substrate W and the cover 37, the cover 37 is lowered from the standby position to the accommodation position. In this state, the ozone gas supply port 19a ejects ozone gas. When the heating plate 36 stops generating heat, the heating plate 36 starts generating heat again. In this way, the ozone gas dissolves in the liquid film of sulfuric acid covering the entire area of the upper surface of the substrate W, and SOM is supplied to the entire area of the upper surface of the substrate W.

[0128] After supplying SOM to the entire area of the upper surface of the substrate W, the ozone gas supply port 19a ejects an inert gas to discharge the ozone gas from between the substrate W and the cover 37. When the substrate W is held by the heating plate 36, the substrate W is moved to the plurality of chuck pins 27b, and the substrate W is rotated by the rotary chuck 27a. In this state, the Figure 7A illustrated rinse liquid nozzle 29a ejects a rinse liquid to rinse 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 using the rotary chuck 27a. Thereby, the substrate W is dried.

[0129] Next, the effects of the present embodiment will be described.

[0130] In the present embodiment, ozone gas as an etching gas is supplied to the amorphous carbon film AC. As a result, the amorphous carbon film AC can be etched without wetting the surface of the substrate W serving as the device formation surface. Furthermore, since the 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 the ozone gas as the etching gas is supplied to the amorphous carbon film AC, ozone-containing sulfuric acid as an etchant, that is, sulfuric acid in which ozone gas as a dissolved gas is dissolved, is supplied to the amorphous carbon film AC. As a result, the amorphous carbon film AC can be further etched.

[0131] The etching rate of the amorphous carbon film AC when supplying the ozone-containing sulfuric acid is less than the etching rate of the amorphous carbon film AC when supplying the ozone gas. Therefore, the etching rate can be increased as compared with the case where the ozone gas etching process is not performed. Furthermore, as compared with the case where the sulfuric acid-ozone etching process is performed before the ozone gas etching process, 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 process and the etching amount of the amorphous carbon film AC in the sulfuric acid-ozone etching process) can be adjusted precisely more easily. In addition, as compared with the case where SPM (Sulfuric acid-Hydrogen Peroxide Mixture) is used instead of the ozone-containing sulfuric acid, the environmental load can be reduced.

[0132] In the present embodiment, the ozone-containing sulfuric acid is supplied to the substrate W while heating the substrate W. As a result, the ozone-containing sulfuric acid can be heated. Peroxydisulfate ions are generated in the ozone-containing sulfuric acid. The peroxydisulfate ions change into sulfate radical ions with stronger oxidizing power. By applying heat energy to the ozone-containing sulfuric acid, the change into sulfate radical ions can be promoted. As a result, the etching rate of the amorphous carbon film AC when supplying the ozone-containing sulfuric acid can be increased.

[0133] In the present 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 free radicals such as oxygen free radicals but also into oxygen molecules. There is also a case where oxygen molecules are generated by the chemical reaction of the free radicals with the amorphous carbon film AC. The oxygen molecules oxidize the surface of the amorphous carbon film AC exposed by the etching of the amorphous carbon film AC, and an oxide film AC1 of the amorphous carbon film AC is formed on the surface layer of the amorphous carbon film AC. The ozone-containing sulfuric acid containing sulfate radical ions etches not only the amorphous carbon film AC but also the oxide film AC1 of the amorphous carbon film AC. Therefore, in the case where the oxide film AC1 of the amorphous carbon film AC is formed, the amorphous carbon film AC can also be etched by the ozone-containing sulfuric acid.

[0134] In this embodiment, one cycle including an ozone gas etching process and a sulfuric acid ozone etching process is performed multiple times. That is, after supplying ozone gas as an etching gas to the substrate W, sulfuric acid containing ozone is supplied to the substrate W as an etching solution. Then, ozone gas as an etching gas is supplied to the substrate W, and sulfuric acid containing ozone is supplied to the substrate W. The oxide film AC1 of the amorphous carbon film AC sometimes reduces the etching rate of the amorphous carbon film AC in the ozone gas etching process. By performing the above cycle multiple times, the oxide film AC1 of the amorphous carbon film AC can be removed, and such a reduction in the etching rate can be prevented.

[0135] In this embodiment, the substrate W is horizontally held with the surface of the substrate W facing upward, and the accommodation space SP1 in which the substrate W is disposed is filled with ozone gas. In this state, sulfuric acid is sprayed toward the surface of the substrate W. Thereby, a liquid film of sulfuric acid covering the entire area of the 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 sulfuric acid containing ozone covering the entire area of the surface of the substrate W is formed. Furthermore, since ozone gas is dissolved in the sulfuric acid in contact with the substrate W, rather than in the sulfuric acid before contacting the substrate W, the time for oxidizing agents such as ozone molecules to reach the amorphous carbon film AC can be shortened.

[0136] In this embodiment, while keeping sulfuric acid containing ozone staying on the surface of the substrate W, sulfuric acid containing ozone is supplied to the entire area of the surface of the substrate W. In other words, sulfuric acid containing ozone is not discharged from the substrate W or is hardly discharged therefrom, and sulfuric acid containing ozone is supplied to the entire area of the surface of the substrate W. Sulfuric acid containing ozone generates oxidizing agents such as peroxydisulfate ions or sulfate radical ions. If sulfuric acid containing ozone is discharged from the substrate W, sometimes such oxidizing agents are discharged from the substrate W before reacting with the amorphous carbon film AC. By keeping sulfuric acid containing ozone staying on the surface of the substrate W, the oxidizing agents discharged from the substrate W before reacting with the amorphous carbon film AC can be reduced.

[0137] Next, other embodiments will be described.

[0138] In the ozone gas etching process, the supply of ozone gas to the substrate W may also be stopped before forming the oxide film ACl of the amorphous carbon film AC.

[0139] In the sulfuric acid ozone etching process, sulfuric acid containing ozone may also be supplied to the substrate W without heating the substrate W.

[0140] Sulfuric acid in which ozone gas is dissolved may also be supplied to the substrate W before contacting the substrate W, rather than dissolving ozone gas in the sulfuric acid in contact with the substrate W. For example, ozone gas may also 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.

[0141] In the sulfuric acid ozone etching process, instead of maintaining the state where the entire upper surface region 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, it is also possible to maintain the state where the entire upper surface region of the substrate W is covered with a liquid film of sulfuric acid while adding new sulfuric acid to the upper surface of the substrate W. The same applies when spraying SOM equivalent to sulfuric acid containing ozone onto the substrate W.

[0142] The substrate processing apparatus 1 is not limited to an apparatus for processing a disk-shaped substrate W, and may also be an apparatus for processing a polygonal substrate W.

[0143] It is also possible to combine two or more of all the above configurations. It is also possible to combine two or more of all the above processes.

[0144] The embodiments of the present invention have been described in detail, but these are merely specific examples for clarifying 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 defined only by the appended claims.

[0145] This application claims priority based on Japanese Patent Application No. 2023-202325 filed on November 30, 2023, the entire content of which is incorporated herein by reference.

Claims

1. A substrate processing method, comprising: an ozone gas etching step of supplying ozone gas as an etching gas to the amorphous carbon film formed on the surface of the substrate while heating the substrate, thereby etching the amorphous carbon film in a dry state on the surface of the substrate; and In the sulfuric acid ozone etching step, after the ozone gas is supplied to the amorphous carbon film, sulfuric acid in which the ozone gas as a dissolved gas is dissolved, that is, ozone-containing sulfuric acid is supplied to the amorphous carbon film, thereby etching the amorphous carbon film. 2 . The substrate processing method according to claim 1 , wherein 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.

3. The substrate processing method according to claim 2, wherein the ozone gas etching step includes the 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. 4 . The substrate processing method according to claim 3 , wherein the following cycle is performed multiple times, wherein the cycle includes the ozone gas etching step and the sulfuric acid ozone etching step.

5. A substrate processing method according to any one of claims 1 to 4, wherein the sulfuric acid ozone etching process includes the following process: while the substrate is horizontally held with the surface of the substrate facing upward and a storage space in which the substrate is arranged is filled with ozone gas, sulfuric acid is sprayed toward the surface of the substrate, thereby forming a liquid film of the ozone-containing sulfuric acid covering the entire area of ​​the surface of the substrate.

6. The substrate processing method according to claim 5, wherein the sulfuric acid ozone etching step includes the following step: while maintaining the entire area of ​​the surface of the substrate covered with the liquid film of the ozone-containing sulfuric acid, the ozone-containing sulfuric acid is allowed to remain on the surface of the substrate.

7. A substrate processing device, comprising: A heater for heating a substrate having an amorphous carbon film formed on the surface thereof; an ozone gas supply port for supplying ozone gas as an etching gas to the amorphous carbon film formed on the surface of the substrate to thereby etch the amorphous carbon film in a state where the surface of the substrate is dry; and The nozzle supplies sulfuric acid, i.e., ozone-containing sulfuric acid, in which ozone gas as a dissolved 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, thereby etching the amorphous carbon film.

8. The substrate processing apparatus according to claim 7, wherein the nozzle supplies the ozone-containing sulfuric acid to the amorphous carbon film while the heater heats the substrate.

9. The substrate processing apparatus according to claim 8, wherein the ozone gas supply port forms 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 nozzle etches the oxide film of the amorphous carbon film by supplying the ozone-containing sulfuric acid to the amorphous carbon film.

10. The substrate processing apparatus according to claim 9, wherein the ozone gas supply port and the nozzle perform a cycle including etching the amorphous carbon film with the ozone gas and etching the amorphous carbon film with the ozone-containing sulfuric acid a plurality of times.

11. A substrate processing device according to any one of claims 7 to 10, wherein the nozzle sprays sulfuric acid toward the surface of the substrate while the substrate is horizontally held with the surface of the substrate facing upward and a storage space containing the substrate is filled with ozone gas, thereby forming a liquid film of the ozone-containing sulfuric acid covering the entire area of ​​the surface of the substrate. 12 . The substrate processing apparatus according to claim 11 , wherein the nozzle allows the ozone-containing sulfuric acid to remain 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.

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