HARDMASK, SUBSTRATE PROCESSING METHOD, AND HARDMASK REMOVAL METHOD

Abstract

To provide a hard mask which improves a selection ratio with respect to a processing target and can be thinned, a substrate processing method, and a removal method for the hard mask.SOLUTION: A hard mask used for etching a processing target includes an oxide containing one or two or more of gallium, indium and zinc.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to hard masks, substrate processing methods, and methods for removing hard masks. [Background technology]

[0002] The manufacturing process of semiconductor devices involves a process in which a specific film, such as a Si-containing film, is processed by plasma etching to form trenches, holes, etc. Resist masks have traditionally been used as masks during etching, but as patterns become finer, resist masks alone do not have sufficient etching resistance, so hard masks are now being used.

[0003] Patent Document 1 describes the use of a combination of any of a SiN film, SiO2 film, SiON film, SiC film, amorphous Si film (a-Si film), and TiN film as a hard mask. Meanwhile, Patent Document 2 describes the use of an a-Si film or an amorphous carbon film (aC film) as a hard mask used when forming recesses such as trenches in a SiO2 film. Furthermore, Patent Document 3 describes the use of a film containing tungsten and a film containing zirconium or titanium and oxygen as a hard mask when etching a silicon-containing film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-37162 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-179218 [Patent Document 3] Patent Publication No. 2021-141260 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a hard mask that has a high selectivity to an object to be processed and can be thinned, a substrate processing method, and a method for removing the hard mask. [Means for solving the problem]

[0006] A hard mask according to one embodiment of the present disclosure is a hard mask used for etching an object to be processed, and includes an oxide containing one or more of gallium, indium, and zinc. The oxide containing one or more of gallium, indium, and zinc is amorphous, and the oxide containing one or more of gallium, indium, and zinc is InGaZnO. 4 , In 2 ZnO 4 , Ga 2 ZnO 4 , In 2 O 3 Either . [Effects of the Invention]

[0007] According to the present disclosure, there are provided a hard mask that has a high selectivity to an object to be processed and can be thinned, a substrate processing method, and a method for removing the hard mask. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a flowchart illustrating a substrate processing method including a series of steps for etching a workpiece using a hard mask according to an embodiment. [Figure 2] 2 is a diagram showing an example of a substrate in step ST1 of the substrate processing method of FIG. 1. FIG. [Figure 3] 1. FIG. 4 is a diagram showing an example of a state in step ST2 of the substrate processing method of FIG. [Figure 4] 1. FIG. 4 is a diagram showing an example of a state in step ST3 of the substrate processing method of FIG. [Figure 5] 1. FIG. 4 is a diagram showing an example of a state of step ST4 of the substrate processing method of FIG. [Figure 6] 1. FIG. 4 is a diagram showing an example of a state of step ST5 of the substrate processing method of FIG. [Figure 7] 1. FIG. 4 is a diagram showing an example of a state of step ST6 of the substrate processing method of FIG. [Figure 8]10A and 10B are diagrams for explaining a method for removing a hard mask by a modification treatment and washing with pure water. [Figure 9] FIG. 1 is a cross-sectional view showing an example of a film formation apparatus used to form a hard mask. [Figure 10] FIG. 1 is a cross-sectional view showing an example of a plasma etching apparatus used for etching a hard mask and an object to be processed. [Figure 11] FIG. 1 is a diagram showing the results of Experimental Example 1. [Figure 12] FIG. 10 is a diagram showing the results of Experimental Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be specifically described with reference to the accompanying drawings.

[0010] <Background and Overview> First, the background and overview will be explained. In the manufacturing process of semiconductor devices, miniaturization is progressing, and the number of etching processes with higher aspect ratios is increasing. In particular, DRAM capacitors and 3D NAND require etching with extremely high aspect ratios. For example, DRAM capacitors require processing with a CD (Critical Dimension) of 20 nm or less, a depth of 1.0 μm or more, and an aspect ratio of 50 or more.

[0011] In high-aspect-ratio etching processes, the etching rate of the workpiece tends to decrease, resulting in increased hard mask wear, necessitating the formation of a thick hard mask. However, increasing the hard mask thickness ultimately leads to deterioration of the roughness of the opening in the workpiece. Conventional hard masks that offer relatively high selectivity include amorphous silicon films, poly-Si films, amorphous carbon films, TiN films, and tungsten-containing films (e.g., WSi films). However, there is a demand for hard masks that offer even higher selectivity and can be made thinner.

[0012] The inventors have investigated hard masks that can be made thinner and have a high selectivity, and have found that an oxide containing one or more of gallium (Ga), indium (In), and zinc (Zn) is effective as a hard mask.

[0013] An example of a processing method using such a hard mask includes the steps of preparing a substrate having a workpiece formed on a base, depositing a hard mask containing an oxide containing one or more of Ga, In, and Zn on the workpiece, etching the hard mask into a desired pattern, and etching the workpiece film using the etched hard mask. This processing method allows the use of a thin hard mask and suppresses deterioration of roughness at openings in the workpiece film.

[0014] <Specific embodiment> Specific embodiments will be described below. Here, a substrate processing method including a series of steps for etching an object to be processed using a hard mask according to one embodiment will be described.

[0015] A flowchart showing such a substrate processing method is shown in Fig. 1. As shown in Fig. 1, this method includes preparing a substrate having a workpiece (step ST1), depositing a hard mask on the workpiece (step ST2), patterning the hard mask (step ST3), etching the hard mask (step ST4), etching the workpiece (step ST5), and removing the hard mask (step ST6).

[0016] As shown in FIG. 2, the substrate in step ST1 may be a substrate 200 having a base 201 on which a workpiece 202 to be etched is formed. A base film for the workpiece 202 may be formed on the base 201. The substrate 200 is not particularly limited and may be, for example, a semiconductor wafer having a semiconductor base such as silicon. The workpiece 202 is not particularly limited, but suitable examples include Si-containing films such as silicon (Si), silicon oxide (SiO), silicon nitride (SiN), silicon oxycarbonitride (SiOCN), and silicon oxynitride (SiON). Si may be single-crystal Si, polycrystalline Si (poly-Si), or amorphous Si. For example, if the target device is a DRAM capacitor, the workpiece is a SiO film. In the case of 3D NAND, the workpiece is a laminated film of a SiO film and a SiN film.

[0017] In step ST2, as shown in Fig. 3, a hard mask 203 according to one embodiment is formed on the object 202 of Fig. 2. The hard mask 203 includes an oxide (IGZO-based film) containing one or more of Ga, In, and Zn. The hard mask 203 according to this embodiment may be entirely or partially composed of such an oxide.

[0018] Such a hard mask 203 allows etching of the workpiece 202 with a high selectivity. This allows for thinning and suppresses roughness deterioration of the opening of the workpiece. In particular, when the workpiece 202 is a Si-containing film, the workpiece 202 can be etched with a high selectivity and can be further thinned.

[0019] In addition, such a hard mask 203 can be formed by etching the workpiece 202 using a fluorocarbon gas (C x F y gas), fluorocarbons (C x H y F zWhen a fluorine (F)-containing gas such as fluorine hexafluoride (SF6) gas is used, the workpiece 202 can be etched with a high selectivity. In particular, such a hard mask 203 is highly effective when the workpiece 202 is a Si-containing film and is etched with an F-containing gas.

[0020] The hard mask 203 is preferably amorphous with no grain boundaries to ensure good shapeability during etching. The method for forming the hard mask 203 is not particularly limited, and any thin film formation technique, such as PVD, CVD, or ALD, or coating (spin coating), can be used. To obtain an amorphous hard mask, PVD, such as sputtering, can be preferably used.

[0021] As oxides (IGZO-based films) containing one or more of Ga, In, and Zn that constitute the hard mask 203, InGaZnO4, In2ZnO4, Ga2ZnO4, In2O3, and ZnO are preferred. These have higher selectivity to the workpiece, particularly Si-containing films, than conventional hard masks such as a-Si films, poly-Si films, aC films, TiN films, and WSi films. Among these, ZnO has a high selectivity, but is prone to crystallization. Even when deposited by PVD, it crystallizes at room temperature and is difficult to form an amorphous film. On the other hand, InGaZnO4, In2ZnO4, Ga2ZnO4, and In2O3 are more preferred because they are prone to amorphization and amorphous films can be easily obtained by PVD.

[0022] The patterning of the hard mask in step ST3 can be performed using, for example, photolithography. Specifically, as shown in FIG. 4, an anti-reflective film 204 and a photoresist film 205 are sequentially formed on a hard mask 203, and then exposed and developed to perform patterning. At this time, the thickness of the photoresist film 205 is adjusted according to the thickness of the hard mask 203. When performing processing with a high selectivity, a film with a high selectivity may be added between the anti-reflective film 204 and the hard mask 203.

[0023] In step ST4, the hard mask is etched using the pattern formed in step ST3. Specifically, as shown in Fig. 5, the hard mask 203 is etched by anisotropic etching using plasma using the photoresist film 205 as a mask.

[0024] As etching gases for etching the hard mask 203 made of an IGZO-based film, HBr gas, Cl2 gas, CH4 gas, CH3OH gas, BCl3 gas, etc. can be used. When using HBr gas or Cl2 gas, halogen-based residues tend to remain, so it is preferable to perform etching at a high temperature of about 120°C and then perform ashing after etching. In addition, when using HBr gas as an etching gas, gas or Cl2 gas When using HBr gas or Cl 2 To gas, One or more of O2 gas, Ar gas, and N2 gas may be added.

[0025] Etching gases include CH4 gas, CH3OH gas, or BCl3 gas In this case, low temperature treatment is possible. CH 4 Gas, CH 3 OH gas, or BCl 3 To gas, H2 gas and Cl2 gas may also be added.

[0026] In step ST5, the object 202 is etched using the hard mask etched in step ST4. Specifically, as shown in Fig. 6, the object 202 is etched by anisotropic etching using plasma using the etched hard mask 203 as a mask.

[0027] Used in step ST5 The etching gas is not particularly limited, but the above-mentioned C x F y Gas, C x H y F z Gas, SF6 gas F-containing gases such as the following can be suitably used. F-containing gas O2 gas, N2 gas, Ar gas, etc. may be added to the gas.

[0028] Such an F-containing gas can be suitably used as an etching gas when the workpiece 202 is the above-mentioned Si-based film. Furthermore, the IGZO-based film constituting the hard mask 203 has high resistance to such an F-containing gas. Furthermore, since the melting and boiling points of the fluorides of In, Ga, and Zn are high, the hard mask 203 made of these elements basically has high etching resistance to an F-containing gas even at high temperatures. However, the lower the temperature, the more difficult it is to etch the hard mask 203, resulting in a higher selectivity.

[0029] 7, the hard mask 203 is removed after etching the object 202. The hard mask 203 can be removed by wet cleaning using a normal chemical solution, or by modification treatment and cleaning with pure water.

[0030] Wet cleaning is performed by selecting an appropriate chemical solution depending on the material of the workpiece 202 that is the base of the hard mask 203. For example, if the workpiece is Si, dilute hydrofluoric acid (DHF) (HF = about 1%) is suitable. Also, if the workpiece is SiO2, a mixed solution (PAN) of phosphoric acid, nitric acid, and acetic acid is suitable. Wet cleaning may be performed by immersing the substrate in a chemical solution stored in a container, or by applying the chemical solution onto the substrate.

[0031] A method for removing the hard mask 203 by modification and rinsing with pure water is described with reference to FIG. 8. First, a modification process is performed by introducing a mixed gas of BCl3 and O2 into the etching chamber used to etch the workpiece 202. During this process, the mixed gas of BCl3 and O2 induces a modification reaction on the surface of the IGZO-based film that constitutes the hard mask 203. For example, if the hard mask 203 is composed of oxides of Ga, In, and Zn (IGZO), these oxides react with BCl3 and O2 on the surface, as shown in FIG. 8(a), and are modified to Zn(ClO3)2, Ga(ClO4)3, and In(ClO4)3. Of these, Zn(ClO3)2 is volatile and evaporates within the chamber. Ga(ClO4)3 and In(ClO4)3 remain, but they are water-soluble. The Zn(ClO3)2 residue can also be removed with pure water. Therefore, as shown in Figure 8(b), after the modification process, the substrate is removed from the chamber and treated with pure water, thereby removing the hard mask 203. This method is unique to IGZO-based films and has the great advantage of easily removing the hard mask 203 even when chemical treatment is not preferred. Furthermore, this method allows the hard mask to be removed with an almost infinite selectivity (with almost no etching of the SiO2) relative to the underlying SiO2 film, which is the processing target.

[0032] The modification process is preferably carried out at temperatures below 60°C, since the film-forming reaction may become dominant at higher temperatures. Furthermore, since the modification rate of the modification process depends on the composition ratio of BCl3 and O2, it is preferable to adjust these composition ratios to obtain the desired modification rate.

[0033] Next, an example of a film forming apparatus for forming a hard mask according to an embodiment will be described in detail. 9 is a cross-sectional view showing an example of a film formation apparatus used to form a hard mask. The film formation apparatus 1 is an apparatus that forms a film by sputtering, which is the preferred film formation method described above. The film formation apparatus 1 has a chamber 10 that is substantially cylindrical and defines a processing space 11. The chamber 10 is made of a metal such as aluminum and is connected to ground potential.

[0034] An exhaust port 14a is provided at the bottom of the chamber 10, and an exhaust device 14 is connected to the exhaust port 14a. The exhaust device 14 includes a pressure control valve and a vacuum pump, and is configured to evacuate the inside of the chamber 10 and control the pressure therein to a desired vacuum level. A load / unload port 12 is provided at the side wall of the chamber 10 for loading / unloading the substrate W into / from the chamber 10, and the load / unload port 12 is opened and closed by a gate valve 13.

[0035] A gas inlet port 15 is provided at the top of the chamber 10 for introducing gas into the processing space 11. The gas inlet port 15 is connected to a gas supply unit (not shown), and gas is supplied from the gas supply unit to the processing space 11 via the gas inlet port 15. The gas supplied may be a rare gas such as Ar gas or an inert gas such as N2 gas.

[0036] A stage 16 on which a substrate W is placed is provided within the chamber 10. The stage 16 may have an electrostatic chuck that electrostatically attracts the substrate W. The stage 16 may also have a temperature control mechanism such as a heater or a coolant flow path. The stage 16 is connected to a drive unit 18. The drive unit 18 includes a support shaft 18a and a drive device 18b. The support shaft 18a extends from the center of the back surface of the stage 16, passing through the bottom of the chamber 10, to the outside. The drive device 18b is configured to rotate and elevate the stage 16 via the support shaft 18a. The space between the support shaft 18a and the bottom wall of the chamber 10 is sealed by a sealing member 40, such as a magnetic fluid seal.

[0037] The ceiling of the chamber 10 is conical and has an inclined surface, to which metal target holders 20 and 22 are attached via insulating members 24 and 26, respectively, facing the stage 16. The target holders 20 and 22 are positioned opposite each other and hold targets 28 and 30, respectively. Power supplies 32 and 34 are electrically connected to the target holders 20 and 22, respectively. The power supplies 32 and 34 may be DC power supplies or radio frequency power supplies. The targets 28 and 30 contain some or all of the material that constitutes the film to be deposited. Note that the number and arrangement of the target holders are not limited to those in this example.

[0038] Magnets 36 and 38 are provided on the backsides of target holders 20 and 22, respectively. Magnets 36 and 38 apply a leakage magnetic field to targets 28 and 30 to perform magnetron sputtering. Magnets 36 and 38 are configured to oscillate along the backsides of target holders 20 and 22 by magnet drivers 36a and 38a, respectively.

[0039] In the film forming apparatus 1 configured as above, the substrate W is carried into the chamber 10 and placed on the stage 16. Then, the driving unit 18 adjusts the vertical position of the stage 16 and rotates the stage 16.

[0040] With the stage 16 rotating, an inert gas such as Ar gas is supplied as a sputtering gas from the gas supply unit into the chamber 10, and the pressure inside the chamber 10 is reduced by the exhaust device 14. Then, power is supplied to the targets 28 and 30 from the power supplies 32 and 34, and the magnets 36 and 38 are driven by the magnet drivers 36a and 38a. As a result, plasma is concentrated near the targets 28 and 30, and positive ions in the plasma collide with the targets 28 and 30, releasing constituent materials from the targets 28 and 30, which are then deposited on the substrate W. In this way, a film that serves as a hard mask is formed on the substrate W.

[0041] The compositions of targets 28 and 30 are adjusted so that the film formed on substrate W will be an IGZO-based film of the desired composition. Targets 28 and 30 may have the same composition or different compositions depending on the composition of the film to be formed. If the compositions are the same, only one of the targets may be used. If the compositions are different, materials released from both targets may be deposited on substrate W to form a film of the desired composition.

[0042] By depositing the IGZO-based film that constitutes the hard mask by sputtering using such a film deposition apparatus 1, it is easy to form an amorphous film that has good shapeability during etching.

[0043] Next, an example of a plasma etching apparatus used for etching the hard mask and the object to be processed in the above-described substrate processing method will be described in detail.

[0044] 10 is a cross-sectional view showing an example of a plasma etching apparatus. Plasma etching apparatus 101 is configured as a capacitively coupled plasma processing apparatus. Plasma etching apparatus 101 has a substantially cylindrical chamber 110 that defines a processing space 111. Chamber 110 is made of metal, for example, aluminum whose surface has been anodized, and is installed in a secure location.

[0045] A cylindrical metal support base 114 is disposed at the bottom of the chamber 110 via an insulating plate 112, and a stage 116 is provided on the support base 114, on which a substrate W made of metal, such as aluminum, is placed. The stage 116 constitutes a lower electrode. An electrostatic chuck 118 is provided on the upper part of the stage 116. The electrostatic chuck 118 has a structure in which an electrode 120 is provided inside an insulator, and by applying a DC voltage to the electrode 120 from an attraction DC power supply 122, the substrate W is attracted and held by electrostatic force such as Coulomb force.

[0046] A focus ring 124 made of a conductive material, such as silicon, is disposed around the electrostatic chuck 118. A cylindrical inner wall member 126 made of an insulating material, such as quartz, is provided on the side surfaces of the stage 116 and the support base 114.

[0047] A coolant chamber 128 is provided inside the support table 114, and a coolant, such as cooling water, is circulated and supplied to the coolant chamber 128 from an external chiller unit (not shown) via pipes 130a and 130b to control the processing temperature of the substrate W on the stage 116. Furthermore, a heat transfer gas, such as He gas, is supplied between the upper surface of the electrostatic chuck 118 and the back surface of the substrate W via a gas supply line 132.

[0048] A first high-frequency power supply 188 for generating plasma and a second high-frequency power supply 191 for applying a bias are electrically connected to the stage 116, which serves as the lower electrode. A matching box 187 is provided on a power feed line 189 that feeds power from the first high-frequency power supply 188 to the stage 116. A power feed line 192 from the second high-frequency power supply 191 is connected to the power feed line 189, and a matching box 190 is provided on the power feed line 192. The matching boxes 187 and 190 are used to match the load (plasma) impedance to the impedance on the first and second high-frequency power supplies 188 and 191 sides, respectively. The first high-frequency power supply 188 for generating plasma has a higher frequency than the second high-frequency power supply 191 for applying a bias.

[0049] Above the stage 116, which is the lower electrode, an upper electrode 134 is provided so as to face the stage 116. Plasma is generated between the upper electrode 134 and the stage (lower electrode) 116.

[0050] The upper electrode 134 is supported above the chamber 110 via an insulating shielding member 143. The upper electrode 134 is composed of an electrode plate 136, which forms the surface facing the stage 116 and has numerous gas outlet holes 137, and a water-cooled electrode support 138 that detachably supports the electrode plate 136. The electrode plate 136 is made of a conductor, such as silicon. The upper electrode 134 is connected to ground potential. A gas diffusion chamber 140 is provided inside the electrode support 138, and numerous gas flow holes 141 extending downward from the gas diffusion chamber 140 and communicating with the gas outlet holes 137. A gas inlet 142 is formed in the electrode support 138 to introduce processing gas into the gas diffusion chamber 140. A gas pipe 151 extending from a gas supply unit 150 (described later) is connected to the gas inlet 142. In other words, the upper electrode 134 is configured as a showerhead.

[0051] The gas supply unit 150 supplies an appropriate etching gas depending on the hard mask and the workpiece. The gas supply unit 150 also supplies an inert gas as a purge gas or a plasma generating gas. As described above, when etching a hard mask, HBr gas, Cl2 gas, CH4 gas, CH3OH gas, BCl3 gas, etc. can be suitably used as the etching gas. When HBr gas or Cl2 gas is used as the etching gas, O2 gas, Ar gas, or N2 gas can be used as an additive gas, and CH4 gas, CH3OH gas, or BCl3 gas can be used as an additive gas. gas When using the above-mentioned gas, H2 gas and Cl2 gas may be used as the additive gas. x F y Gas, C x H y F z Gas, SF6 gasThe F-containing gas may preferably be O2 gas, N2 gas, Ar gas, or the like.

[0052] An exhaust port 160 is provided at the bottom of the chamber 110, and an exhaust device 164 is connected to the exhaust port 160 via an exhaust pipe 162. The exhaust device 164 includes a pressure control valve and a vacuum pump, and is configured to evacuate the inside of the chamber 110 using the exhaust device 164 and control the pressure inside the chamber 110 to a desired vacuum level. A load / unload port 165 is provided at the side wall of the chamber 110 for loading and unloading the substrate W into and out of the chamber 110, and the load / unload port 165 is opened and closed by a gate valve 166.

[0053] In the etching apparatus 101 configured as described above, the substrate W is loaded into the chamber 110 and placed on the stage 116. Then, an inert gas is supplied into the chamber 110 from the gas supply unit 150, and the pressure inside the chamber 110 is reduced by the exhaust unit 164. In this state, while an etching gas is supplied from the gas supply unit 150, plasma-generating high-frequency power is applied from the first high-frequency power supply 188 to the stage 116, which serves as the lower electrode, and bias-applying high-frequency power is applied to the stage 116 from the second high-frequency power supply 191. As a result, a capacitively coupled plasma is formed between the upper electrode 134 and the stage 116, which serves as the lower electrode, and ions in the plasma are attracted to the stage 116, thereby anisotropically etching the hard mask or the workpiece on the substrate W.

[0054] <Experimental Example> Next, an experimental example will be described.

[0055] [Experimental Example 1] In Experimental Example 1, we conducted an experiment on the etching of SiO2 films used in processes such as the formation of DRAM. Here, we etched the SiO2 films using various IGZO-based films, as well as conventional poly-Si films and WSi films as hard masks, to determine the selectivity. The IGZO-based films used were InGaZnO4 film, In2ZnO4 film, Ga2ZnO4 film, In2O3 film, and ZnO film. The hard masks were formed by sputtering using the film formation system shown in Figure 9. The workpiece was etched using the system shown in Figure 10, using C4F8 gas, C4F6 gas, and O2 gas as etching gases.

[0056] The results are shown in Figure 11. Figure 11 is a diagram showing the selectivity of various hard masks to the SiO2 material to be processed, normalized with the selectivity of the poly-Si film set to 1. As shown in Figure 11, the hard masks used for etching the SiO2 film were the above IGZO-based membrane If you use Both are conventional poly-Si films and WSi films. When using A higher selectivity was obtained than that of the conventional IGZO-based film. In other words, it was confirmed that by using the IGZO-based film of this embodiment as a hard mask when etching an SiO2 film in the DRAM formation process, the selectivity to the object to be processed was higher than that of conventional hard masks, making it possible to reduce the thickness. Furthermore, among these IGZO-based films, the InGaZnO4 film, In2ZnO4 film, Ga2ZnO4 film, and In2O3 film were amorphous as deposited, while the ZnO film was crystalline as deposited. This confirmed that the InGaZnO4 film, In2ZnO4 film, Ga2ZnO4 film, and In2O3 film were more preferable in terms of shape.

[0057] [Experimental Example 2] In Experimental Example 2, we conducted an experiment on the etching of SiO2 / SiN laminated films used in processes such as the formation of 3D NAND. Here, we performed etching of SiO2 / SiN laminated films using various IGZO-based films, a conventional amorphous carbon (ACL) film, and a WSi film as hard masks to determine the selectivity. The IGZO-based films used were InGaZnO4, In2ZnO4, Ga2ZnO4, In2O3, and ZnO. The hard masks were deposited by sputtering using the deposition system shown in Figure 9. Furthermore, the target film was etched using the system shown in Figure 10, using C4F8, C4F6, O2, and CH2F2 gases as etching gases.

[0058] The results are shown in Figure 12. Figure 12 is a diagram showing the selectivity of various hard masks to the SiO2 / SiN laminated film, which is the processing target, normalized with the selectivity of the ACL film set to 1. As shown in Figure 12, the hard masks used for etching the SiO2 / SiN laminated film were the above IGZO-based membrane If you use Both are conventional ACL membranes and WSi membranes. When using A higher selectivity was obtained than in the conventional method. That is, it was confirmed that by using the IGZO-based film of this embodiment as a hard mask when etching an SiO2 / SiN stacked film in the 3D NAND formation process, the selectivity to the workpiece was higher than in the conventional method, and thinning was possible. Furthermore, as in Experimental Example 1, among these IGZO-based films, the InGaZnO4 film, In2ZnO4 film, Ga2ZnO4 film, and In2O3 film were amorphous as formed, while the ZnO film was crystalline as formed. From this, it was confirmed that the InGaZnO4 film, In2ZnO4 film, Ga2ZnO4 film, and In2O3 film were more preferable in terms of shapeability.

[0059] <Other applications> Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0060] For example, in the above embodiment, the sputtering apparatus shown in Fig. 9 is used as an example of the film formation apparatus, but the present invention is not limited to this. It may be a PVD apparatus with a different structure, or a film formation apparatus using other film formation techniques such as CVD or ALD, or may even be an apparatus that performs coating (spin coating).

[0061] 10 is used as an example of an etching apparatus, but the present invention is not limited to this. A capacitively coupled plasma processing apparatus having a different structure may be used, or an apparatus using other plasma such as an inductively coupled plasma processing apparatus or a microwave plasma processing apparatus may be used. [Explanation of symbols]

[0062] 1; Film deposition equipment 10; Chamber 16 Stage 32,34;Power supply 28,30; Target 101; Plasma etching equipment 110;Chamber 116: Stage (lower electrode) 134;Top electrode 150 Gas supply unit 188: First high frequency power supply 191; Second high frequency power supply 200;Substrate 201;Substrate 202;Processing object 203;Hard Mask W; substrate

Claims

1. A hard mask used in etching an object to be processed, comprising an oxide containing one or more of gallium, indium, and zinc; the oxide containing one or more of gallium, indium, and zinc is amorphous; The hard mask, wherein the oxide containing one or more of gallium, indium, and zinc is any one of InGaZnO 4 , In 2 ZnO 4 , Ga 2 ZnO 4 , and In 2 O 3 .

2. The hard mask of claim 1 , wherein the workpiece is a silicon-containing film.

3. 3. The hard mask according to claim 1, wherein the etching of the object is performed using a fluorine-containing gas.

4. providing a substrate having a workpiece; forming a hard mask containing an oxide containing one or more of gallium, indium, and zinc on the object to be processed; Etching the hard mask into a desired pattern; Etching the object using the hard mask as a mask; and the oxide containing one or more of gallium, indium, and zinc is amorphous; The substrate processing method, wherein the oxide containing one or more of gallium, indium, and zinc is any one of InGaZnO 4 , In 2 ZnO 4 , Ga 2 ZnO 4 , and In 2 O 3 .

5. The substrate processing method according to claim 4 , wherein the object to be processed is a silicon-containing film.

6. 6. The substrate processing method according to claim 4, wherein the step of etching the object is performed using a fluorine-containing gas.

7. 7. The substrate processing method according to claim 4, wherein the step of forming the hard mask is performed by physical vapor deposition.

8. 8. The substrate processing method according to claim 4, wherein the step of etching the hard mask into a desired pattern and the step of etching the object are performed by anisotropic etching using plasma.

9. 9. The substrate processing method according to claim 4, wherein the step of etching the hard mask into a desired pattern includes patterning the hard mask by photolithography, and then etching the hard mask with the pattern formed by the patterning.

10. After the step of etching the object, the hard mask is ３ and O ２ 10. The substrate processing method according to claim 4, further comprising the steps of modifying the hard mask by supplying a mixed gas of the above and the above and then removing the hard mask by washing with pure water.

11. A hard mask removal method for etching an object to be processed using a hard mask containing an oxide containing one or more of gallium, indium, and zinc as a mask, and then removing the hard mask, the method comprising: The hard mask is ３ and O ２ modifying the hard mask by supplying a mixed gas of After modifying the hard mask, the hard mask is washed with pure water and then removed. A method for removing a hard mask comprising:

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