Plasma Processing Equipment

Abstract

To provide a technology that protects a surface within a chamber from reactive species.SOLUTION: In one exemplary embodiment, an etching method is provided. The etching method comprises: a step (a) of forming a protection film on a surface within a chamber. The etching method further comprises: a step (b) of etching an etching film of a substrate using hydrogen fluoride within the chamber. The substrate includes the etching film, and a mask provided on the etching film. A protection film is formed from the same kind of material as a material of the mask.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] Exemplary embodiments of the present disclosure relate to an etching method and a plasma processing apparatus. [Background technology]

[0002] A plasma processing apparatus is used in plasma processing such as etching. The plasma processing apparatus includes a chamber. A surface in the chamber is exposed to reactive species used in the plasma processing and is removed by the reactive species. In order to protect the surface in the chamber from the reactive species, a technique is used in which a protective film is formed on the surface in the chamber before performing plasma processing on a substrate. The following Patent Documents 1 to 3 disclose such techniques. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-76625 A [Patent Document 2] JP 2009-188257 A [Patent Document 3] U.S. Patent No. 6,071,573 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for protecting surfaces within a chamber from reactive species. [Means for solving the problem]

[0005] In one exemplary embodiment, an etching method is provided. The etching method includes the step (a) of forming a protective film on a surface in a chamber. The etching method further includes the step (b) of etching the etch film of a substrate using hydrogen fluoride in the chamber. The substrate includes an etch film and a mask disposed on the etch film. The protective film is formed of the same material as the material of the mask. Effect of the Invention

[0006] According to one exemplary embodiment, surfaces within the chamber may be protected from reactive species. [Brief description of the drawings]

[0007] [Figure 1] 1 is a flow diagram of an etching method according to an exemplary embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a portion of an example substrate. [Diagram 3] 1 is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment; [Figure 4] FIG. 2 illustrates a state in which a protective film is formed on a surface within a chamber of a plasma processing apparatus according to an exemplary embodiment. [Diagram 5] FIG. 2 is a partial enlarged cross-sectional view of an example substrate after etching has been performed. [Figure 6] FIG. 2 illustrates the state of a chamber after etching has been performed in a plasma processing apparatus according to an exemplary embodiment. [Figure 7] FIG. 2 illustrates the state of a chamber after dry cleaning in a plasma processing apparatus according to an exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Various exemplary embodiments are described below.

[0009] In one exemplary embodiment, an etching method is provided. The etching method includes the step (a) of forming a protective film on a surface in a chamber. The etching method further includes the step (b) of etching the etching film of a substrate using hydrogen fluoride in the chamber. The substrate includes an etching film and a mask disposed on the etching film. The protective film is formed of the same material as the material of the mask.

[0010] In the above embodiment, a protective film is formed on the surface inside the chamber before etching the etching film using hydrogen fluoride. The protective film is made of the same material as the mask material and is therefore difficult to etch. Therefore, according to the above embodiment, it is possible to more effectively protect the surface inside the chamber from reactive species.

[0011] In one exemplary embodiment, hydrogen fluoride may be generated from a process gas that includes a hydrogen-containing gas and a fluorine-containing gas, or that includes hydrogen fluoride.

[0012] In one exemplary embodiment, the etch film may contain silicon and the mask and protective film may contain carbon, or the etch film may contain metal.

[0013] In one exemplary embodiment, the mask may be formed from an amorphous carbon film.

[0014] In one exemplary embodiment, the etching film may include a silicon oxide film, a polycrystalline silicon film, a silicon nitride film, or a multi-layer film including a silicon oxide film and a silicon nitride film.

[0015] In one exemplary embodiment, the protective coating may be formed using a hydrocarbon-containing gas.

[0016] In one exemplary embodiment, the mask may be formed from a metal-containing film and the protective film may contain a metal.

[0017] In one exemplary embodiment, the mask and protective film may be formed from polysilicon or silicon oxide.

[0018] In one exemplary embodiment, the etching method may further include, after step (b), a step (c) of performing dry cleaning to remove reaction products deposited on the protective film together with at least a portion of the protective film.

[0019] In one exemplary embodiment, dry cleaning may be performed such that the protective film remains partially coated on the surfaces within the chamber, in which case step (b) may be further performed on another substrate after step (c).

[0020] In one exemplary embodiment, after step (b), step (a) may be further performed, and step (b) may be performed on another substrate.

[0021] In another exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a gas supply unit, a plasma generation unit, and a control unit. The gas supply unit is configured to supply a gas into the chamber. The plasma generation unit is configured to generate plasma from the gas in the chamber. The control unit is configured to control the gas supply unit and the plasma generation unit. The control unit controls the gas supply unit to supply a deposition gas into the chamber to form a protective film on a surface in the chamber. The control unit controls the gas supply unit and the plasma generation unit to generate plasma from an etching gas to etch an etching film of a substrate with hydrogen fluoride in the chamber. The deposition gas includes a precursor that forms a protective film from the same material as a material of a mask provided on the etching film of the substrate.

[0022] Various exemplary embodiments will now be described in detail with reference to the drawings, in which the same or corresponding parts are designated by the same reference numerals.

[0023] 1 is a flow diagram of an etching method according to an exemplary embodiment. The etching method shown in FIG. 1 (hereinafter referred to as "method MT") is performed to etch an etch film of a substrate.

[0024] Fig. 2 is a partially enlarged cross-sectional view of an example substrate. The method MT may be applied to the substrate W shown in Fig. 2. The substrate W has a film EF and a mask MK. The substrate W may further have an underlayer region UR. The film EF may be provided on the underlayer region UR.

[0025] The film EF is an etching film to be etched in the method MT. The film EF is, for example, a silicon-containing film. The silicon-containing film may be a single-layer film or a multilayer film. The single-layer film is, for example, a silicon oxide film, a silicon nitride film, a polycrystalline silicon film, or a silicon-containing low dielectric constant film. The multilayer film is formed of two or more of a silicon oxide film, a silicon nitride film, and a polycrystalline silicon film. The multilayer film may be a stacked film including a silicon oxide film and a silicon nitride film. The film EF may be formed of other materials. For example, the film EF may be formed of a metal.

[0026] The mask MK is provided on the film EF. The mask MK can be made of any material as long as the film EF can be selectively etched with respect to the mask MK. The mask MK is made of, for example, an organic film such as a photoresist film, an amorphous carbon film, or a spin-on carbon film, a silicon-containing film, or a metal-containing film. The silicon-containing film is a polycrystalline silicon film or a silicon oxide film. The metal-containing film is made of titanium, titanium nitride, titanium carbide, titanium oxide, tungsten, tungsten carbide, ruthenium, ruthenium oxide, molybdenum, molybdenum carbide, or the like. The mask MK has a pattern to be transferred to the film EF. That is, the mask MK provides an opening OP.

[0027] In the method MT, a plasma processing apparatus is used. Fig. 3 is a schematic diagram of a plasma processing apparatus according to an exemplary embodiment. The plasma processing apparatus 1 shown in Fig. 3 is a capacitively coupled plasma processing apparatus.

[0028] The plasma processing apparatus 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The central axis of the chamber 10 is an axis AX extending in the vertical direction. In one embodiment, the chamber 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The internal space 10s is provided in the chamber body 12. The chamber body 12 is made of, for example, aluminum. The chamber body 12 is electrically grounded. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The corrosion-resistant film may be a film made of a ceramic such as aluminum oxide or yttrium oxide.

[0029] The chamber body 12 provides a passage 12p in its sidewall. The substrate W passes through the passage 12p when being transferred between the internal space 10s and the outside of the chamber 10. The passage 12p can be opened and closed by a gate valve 12g. The gate valve 12g is provided along the sidewall of the chamber body 12.

[0030] The plasma processing apparatus 1 further includes a substrate support 16. The substrate support 16 is configured to support a substrate W in the chamber 10. The substrate W may have a substantially disk-like shape. The substrate support 16 may be supported by a support 15. The support 15 extends upward from the bottom of the chamber body 12. The support 15 has a substantially cylindrical shape. The support 15 is made of an insulating material such as quartz.

[0031] The substrate support 16 may include a lower electrode 18 and an electrostatic chuck 20. The substrate support 16 may further include an electrode plate 19. The electrode plate 19 is made of a conductive material such as aluminum. The electrode plate 19 has a substantially disk-like shape, and its central axis is an axis line AX. The lower electrode 18 is provided on the electrode plate 19. The lower electrode 18 is made of a conductive material such as aluminum. The lower electrode 18 has a substantially disk-like shape, and its central axis is an axis line AX. The lower electrode 18 is electrically connected to the electrode plate 19.

[0032] The lower electrode 18 provides a flow path 18f therein. The flow path 18f is a flow path for a heat exchange medium (e.g., a coolant). The flow path 18f receives the heat exchange medium from a supply device (e.g., a chiller unit) via a pipe 23a. This supply device is provided outside the chamber 10. The heat exchange medium supplied to the flow path 18f flows through the flow path 18f and is returned to the supply device via a pipe 23b. The supply device for the heat exchange medium constitutes a temperature adjustment mechanism of the plasma processing device 1.

[0033] The electrostatic chuck 20 is provided on the lower electrode 18. The substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a body and an electrode. The body of the electrostatic chuck 20 is formed from a dielectric material. The electrostatic chuck 20 and its body each have a substantially disk shape, and the central axis is an axis line AX. The electrode of the electrostatic chuck 20 is a film-like electrode and is provided in the body of the electrostatic chuck 20. The electrode of the electrostatic chuck 20 is connected to a DC power supply via a switch. When a voltage from the DC power supply is applied to the electrode of the electrostatic chuck 20, an electrostatic attractive force is generated between the electrostatic chuck 20 and the substrate W. Due to the generated electrostatic attractive force, the substrate W is attracted to the electrostatic chuck 20 and held by the electrostatic chuck 20.

[0034] The substrate support 16 may further support an edge ring ER disposed thereon. The edge ring ER may be made of silicon, silicon carbide, or quartz. The substrate W is disposed on the electrostatic chuck 20 and within a region surrounded by the edge ring ER.

[0035] The plasma processing apparatus 1 may further include a gas supply line 25. The gas supply line 25 supplies a heat transfer gas (e.g., He gas) from a gas supply mechanism to the gap between the upper surface of the electrostatic chuck 20 and the rear surface (lower surface) of the substrate W.

[0036] The plasma processing apparatus 1 may further include a cylindrical portion 28 and an insulating portion 29. The cylindrical portion 28 extends upward from the bottom of the chamber body 12. The cylindrical portion 28 extends along the outer periphery of the support 15. The cylindrical portion 28 is formed of a conductive material and has a substantially cylindrical shape. The cylindrical portion 28 is electrically grounded. The insulating portion 29 is provided on the cylindrical portion 28. The insulating portion 29 is formed of a material having insulating properties. The insulating portion 29 is formed of a ceramic such as quartz. The insulating portion 29 has a substantially cylindrical shape. The insulating portion 29 extends along the outer periphery of the electrode plate 19, the outer periphery of the lower electrode 18, and the outer periphery of the electrostatic chuck 20.

[0037] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 16. The upper electrode 30 is supported on the upper part of the chamber body 12 via a member 32. The member 32 is made of an insulating material. The upper electrode 30 and the member 32 close the upper opening of the chamber body 12.

[0038] The upper electrode 30 may include a top plate 34 and a support 36. The bottom surface of the top plate 34 is the bottom surface on the side of the internal space 10s and defines the internal space 10s. The top plate 34 may be made of a low-resistance conductor or semiconductor with little Joule heat. In one embodiment, the top plate 34 is made of silicon. The top plate 34 provides a plurality of gas holes 34a. The plurality of gas holes 34a penetrate the top plate 34 in the plate thickness direction.

[0039] The support 36 detachably supports the top plate 34. The support 36 is made of a conductive material such as aluminum. The support 36 provides a gas diffusion chamber 36a therein. The support 36 further provides a plurality of gas holes 36b. The plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b communicate with the plurality of gas holes 34a, respectively. The support 36 further provides a gas inlet 36c. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0040] A gas source group 40 is connected to the gas supply pipe 38 via a valve group 41, a flow rate controller group 42, and a valve group 43. The gas source group 40, the valve group 41, the flow rate controller group 42, and the valve group 43 constitute a gas supply unit GS. The gas source group 40 includes a plurality of gas sources. The gas sources of the gas source group 40 include a plurality of gas sources used in the method MT. Each of the valve group 41 and the valve group 43 includes a plurality of opening and closing valves. The flow rate controller group 42 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers of the flow rate controller group 42 is a mass flow controller or a pressure control type flow rate controller. Each of the plurality of gas sources of the gas source group 40 is connected to the gas supply pipe 38 via a corresponding opening and closing valve of the valve group 41, a corresponding flow rate controller of the flow rate controller group 42, and a corresponding opening and closing valve of the valve group 43.

[0041] The plasma processing apparatus 1 may further include a shield 46. The shield 46 is detachably provided along the inner wall surface of the chamber body 12. The shield 46 prevents by-products of the plasma processing from adhering to the chamber body 12. The shield 46 is configured by forming a corrosion-resistant film on the surface of a member made of, for example, aluminum. The corrosion-resistant film may be a film made of a ceramic such as yttrium oxide.

[0042] The plasma processing apparatus 1 may further include a baffle member 48. The baffle member 48 is provided between a member (e.g., the cylindrical portion 28) surrounding the substrate support 16 and the shield 46. The baffle member 48 is formed by forming a corrosion-resistant film on the surface of a member made of, for example, aluminum. The corrosion-resistant film may be a film made of ceramic such as yttrium oxide. The baffle member 48 has a plurality of through holes. An exhaust port is provided below the baffle member 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port via an exhaust pipe 52. The exhaust device 50 has a pressure adjustment valve and a vacuum pump such as a turbo molecular pump.

[0043] The plasma processing apparatus 1 further includes a high-frequency power supply 61 and a bias power supply 62. The high-frequency power supply 61 is configured to generate high-frequency power (hereinafter, referred to as "high-frequency power HF"). The high-frequency power HF has a frequency suitable for generating plasma. The frequency of the high-frequency power HF is, for example, 27 MHz or more and 100 MHz or less. The high-frequency power supply 61 is connected to the lower electrode 18 via a matching device 61m. The matching device 61m has a circuit for matching the impedance of the load side (lower electrode 18 side) of the high-frequency power supply 61 to the output impedance of the high-frequency power supply 61. In one embodiment, the high-frequency power supply 61 can constitute a plasma generating unit. The high-frequency power supply 61 may be connected to the upper electrode 30 via the matching device 61m.

[0044] The bias power supply 62 is configured to apply an electric bias EB to the lower electrode 18. The electric bias EB has a frequency suitable for attracting ions to the substrate W. The frequency of the electric bias EB is, for example, 100 kHz or more and 40.68 MHz or less. When the electric bias EB is used together with the high frequency power HF, the electric bias EB has a frequency lower than the frequency of the high frequency power HF.

[0045] In one embodiment, the electric bias EB may be a high frequency bias power (hereinafter referred to as "high frequency power LF"). In this embodiment, the bias power supply 62 is connected to the lower electrode 18 via a matching device 62m. The matching device 62m has a circuit for matching the impedance of the load side (lower electrode 18 side) of the bias power supply 62 to the output impedance of the bias power supply 62. The plasma processing apparatus 1 may be configured to generate plasma using only the high frequency power LF. In this case, the bias power supply 62 constitutes a plasma generating unit of one embodiment. In this case, the plasma processing apparatus 1 does not need to include the high frequency power supply 61 and the matching device 61m.

[0046] In one embodiment, the electrical bias EB may be a pulse of negative DC voltage, which is periodically applied to the bottom electrode 18.

[0047] The plasma processing apparatus 1 further includes a control unit 80. The control unit 80 is a computer including a processor, a storage device, an input device, a display device, etc., and controls each part of the plasma processing apparatus 1. Specifically, the control unit 80 executes a control program stored in the storage device, and controls each part of the plasma processing apparatus 1 based on recipe data stored in the storage device. Under the control of the control unit 80, a process specified by the recipe data is executed in the plasma processing apparatus 1. The method MT can be executed in the plasma processing apparatus 1 under the control of the control unit 80 for each part of the plasma processing apparatus 1.

[0048] Method MT will be described in detail with reference to FIG. 1 again. Method MT will be described below by taking as an example a case where method MT is applied to a substrate W shown in FIG. 2 using a plasma processing apparatus 1. In the following description, reference will be made further to FIGS. 4 to 7. FIG. 4 is a diagram showing a state where a protective film is formed on a surface in a chamber of a plasma processing apparatus according to an exemplary embodiment. FIG. 5 is a partially enlarged cross-sectional view of an example of a substrate after etching has been performed. FIG. 6 is a diagram showing a state of a chamber after etching has been performed in a plasma processing apparatus according to an exemplary embodiment. FIG. 7 is a diagram showing a state of a chamber after dry cleaning has been performed in a plasma processing apparatus according to an exemplary embodiment.

[0049] As shown in FIG. 1, the method MT starts with step STa. In step STa, as shown in FIG. 4, a protective film PF is formed on a surface in the chamber 10. The surface in the chamber 10 is a surface to which a reaction product generated during etching in step STb described below may adhere if the protective film PF is not formed thereon. In one example, the surfaces in the chamber 10 include the lower surface of the upper electrode 30 (i.e., the lower surface of the top plate 34), the surface of the shield 46, the surface of the insulating part 29, and the surface of the edge ring ER. As shown in FIG. 4, step STa may be performed in a state in which a dummy substrate DW is placed on the substrate support 16.

[0050] The protective film PF is formed of the same material as the material of the mask MK. When the mask MK is formed of an organic film, the protective film PF is formed of a carbon-containing material. When the mask MK is formed of a silicon-containing film, the protective film PF is formed of a silicon-containing material (e.g., a silicon-containing film containing polycrystalline silicon, silicon oxide, or carbon). When the mask MK is formed of a metal-containing film, the protective film PF is formed of a metal-containing material. The metal-containing material includes any of titanium, titanium nitride, titanium carbide, titanium oxide, tungsten, tungsten carbide, ruthenium, ruthenium oxide, molybdenum, molybdenum carbide, etc.

[0051] The protective film PF made of a carbon-containing material is formed in the chamber 10 using a deposition gas. The deposition gas includes a carbon-containing gas. The deposition gas may be a gas that does not contain fluorine. The carbon-containing gas includes one or more of CO, CO2, COS, and a hydrocarbon as a precursor. The hydrocarbon may be CH4, C2H2, C3H6, etc. The protective film PF made of a carbon-containing material may be formed by a CVD (chemical vapor deposition) method or an MLD (molecular layer deposition) method. The CVD method may be a plasma-assisted CVD method or a thermal CVD method. The MLD method may be a plasma-assisted MLD method or a thermal MLD method. In the MLD method, a protective film having a urea bond may be formed by mixing two or more types of gases.

[0052] In step STa, in order to form a protective film PF made of a carbon-containing material, the control unit 80 controls the gas supply unit GS to supply a film formation gas into the chamber 10. The control unit 80 controls the exhaust unit 50 to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit 80 controls the plasma generation unit to generate plasma of the film formation gas in the chamber 10. In the plasma processing apparatus 1, the control unit 80 controls the high frequency power supply 61 and / or the bias power supply 62 to supply high frequency power HF and / or an electric bias EB.

[0053] The protective film PF made of a silicon-containing material is formed by using a CVD method or an ALD (atomic layer deposition) method. The CVD method may be a plasma-assisted CVD method or a thermal CVD method. The ALD method may be a plasma-assisted ALD method or a thermal ALD method. In order to form the protective film PF made of a silicon-containing material in the step STa, the control unit 80 controls the gas supply unit GS to supply a film-forming gas containing a silicon-containing material as a precursor into the chamber 10. When the protective film PF made of a silicon-containing material is formed, the film-forming gas contains, for example, SiH4, SiCl4, Si2Cl6, or SiF4. The film-forming gas may further contain a rare gas such as argon. When the protective film PF made of silicon oxide is formed, an oxygen-containing gas containing oxygen that reacts with the precursor may further be used.

[0054] The protective film PF made of a metal-containing material is formed by chemical vapor deposition, metal-organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD). When using these deposition methods, a deposition gas containing a metal-containing material as a precursor is supplied into the chamber 10. The deposition gas may be, for example, WF6, TiCl4, or CH. 24 The metal-containing gas includes N4Ti, RuCl3, or MoCl5. In order to form the protective film PF made of a metal-containing substance in the step STa, the control unit 80 controls the gas supply unit GS to supply a film formation gas into the chamber 10.

[0055] When the protective film PF is formed of tungsten, the deposition gas may include WF6. The deposition gas is supplied into the chamber 10 such that the precursor WF6 is adsorbed on the surfaces in the chamber 10. The WF6 is modified by chemical species from the plasma of a hydrogen-containing gas (e.g., H2 gas) generated in the chamber 10. As a result, the protective film PF made of tungsten is formed on the surfaces in the chamber 10. Alternatively, the protective film PF made of tungsten may be formed by a plasma-assisted CVD method or a thermal CVD method using a deposition gas containing WF6.

[0056] When the protective film PF is made of titanium, the deposition gas includes, for example, TiCl4 and H2, and the protective film PF is formed by a plasma-assisted CVD method or a thermal CVD method. When the protective film PF is made of titanium nitride, the deposition gas includes, for example, TiCl4 and N2, and the protective film PF is formed by a plasma-assisted CVD method or a thermal CVD method. Alternatively, when the protective film PF is made of titanium nitride, the deposition gas includes, for example, Ti[N(CH3)C2H5]4, and the protective film PF is formed by an MOCVD method.

[0057] In the method MT, the substrate W is then placed on the substrate support 16. Then, step STb is performed. In step STb, the film EF is etched as shown in FIG. 5. The depth of the opening OP is increased by etching the film EF in step STb. In step STb, the film EF can be etched until the underlying region UR is exposed.

[0058] In step STb, the film EF is etched by using hydrogen fluoride in the chamber 10. In order to generate hydrogen fluoride, in step STb, an etching gas is supplied into the chamber 10, and plasma is generated from the etching gas in the chamber 10.

[0059] The etching gas may include hydrogen fluoride (HF). Alternatively, the etching gas may include a fluorine-containing gas as a fluorine source and a hydrogen-containing gas as a hydrogen source. The etching gas may include one or more of H2, CH4, CH2F2, CH3F, CHF3, H2O, HF, HCl, HBr, HI, etc. as a hydrogen source. The etching gas may include one or more of CF4, C4F8, C4F6, C3F8, C5F8, SF 6、 It may contain one or more of NF3, XeF2, PF3, PF5, CF3I, C2F5I, C3F7I, IF5, IF7, WF6, HF, SiF4, etc.

[0060] The etching gas may further include one or more phosphorus-containing molecules. The one or more phosphorus-containing molecules may be tetraphosphorus decaoxide (PO 10 The one or more phosphorus-containing molecules may include oxides such as phosphorus trifluoride (PF3), phosphorus pentafluoride (PF5), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), phosphorus tribromide (PBr3), phosphorus pentabromide (PBr5), and phosphorus iodide (PI3). The one or more phosphorus-containing molecules may include phosphoryl halides such as phosphoryl fluoride (POF3), phosphoryl chloride (POCl3), and phosphoryl bromide (POBr3). The one or more phosphorus-containing molecules may include phosphine (PH3), calcium phosphide (e.g., Ca3P2), phosphoric acid (H3PO4), sodium phosphate (Na3PO4), hexafluorophosphoric acid (HPF6), and the like. The one or more phosphorus-containing molecules may include fluorophosphines (H x PF yHere, the sum of x and y is 3 or 5. Examples of fluorophosphines include HPF2 and H2PF3.

[0061] In one example, the etching gas may be a gas mixture including hydrogen fluoride gas, a fluorocarbon gas such as C4F8 gas, and a phosphorus-containing gas, the phosphorus-containing gas including one or more of the phosphorus-containing molecules described above.

[0062] To etch the film EF in step STb, the control unit 80 controls the gas supply unit GS to supply an etching gas into the chamber 10. The control unit 80 controls the exhaust unit 50 to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit 80 controls the plasma generation unit to generate plasma of the etching gas in the chamber 10. In the plasma processing apparatus 1, the control unit 80 controls the high frequency power supply 61 and / or the bias power supply 62 to supply high frequency power HF and / or an electric bias EB.

[0063] When etching is performed in step STb, reaction products RP are generated. The reaction products RP adhere to the surfaces in the chamber 10, as shown in FIG.

[0064] In the method MT, after the execution of the step STb, the substrate W is unloaded from the inside of the chamber 10. Then, the step STc is executed. In the step STc, the chamber 10 is dry-cleaned. The dry-cleaning in the step STc can be executed with or without a dummy substrate placed on the substrate support 16.

[0065] In step STc, a cleaning gas is supplied into the chamber 10, and plasma is generated from the cleaning gas. Chemical species from the generated cleaning gas remove the reaction product RP together with at least a portion of the protective film PF. The dry cleaning in step STc may completely remove the protective film PF as shown in FIG. 7. The dry cleaning in step STc may be performed such that the protective film PF partially remains while covering the surface inside the chamber 10.

[0066] When the protective film PF is made of a carbon-containing material, an oxygen-containing gas (e.g., O2 gas) is used as the cleaning gas. When the protective film PF is made of a silicon-containing material, a halogen-containing gas is used as the cleaning gas. When the protective film PF is made of a metal-containing material, the cleaning gas includes NF3, Cl2, BCl3, SiCl4, O2, CH3OH, C2H5OH, etc.

[0067] To perform dry cleaning in step STc, the control unit 80 controls the gas supply unit GS to supply a cleaning gas into the chamber 10. The control unit 80 controls the exhaust unit 50 to set the gas pressure in the chamber 10 to a designated pressure. The control unit 80 controls the plasma generation unit to generate plasma of the cleaning gas in the chamber 10. In the plasma processing apparatus 1, the control unit 80 controls the high frequency power supply 61 and / or the bias power supply 62 to supply high frequency power HF and / or an electric bias EB.

[0068] The method MT may further include a step STJ, in which it is determined whether a stop condition is satisfied. The stop condition is not satisfied if there are further substrates to be etched, whereas the stop condition is satisfied if etching of all substrates has been completed.

[0069] If it is determined that the stop condition is not satisfied in step STJ, the process continues to etch another substrate W. If the protective film PF is removed by the dry cleaning in step STc to expose the surface in the chamber 10, step STa is executed again. Thereafter, another substrate W is placed on the substrate support 16, and step STb is executed. Alternatively, if the protective film PF remains to cover the surface in the chamber 10 after the dry cleaning in step STc, another substrate W is placed on the substrate support 16, and step STb is executed without executing step STa. If it is determined that the stop condition is satisfied in step STJ, the method MT ends.

[0070] In method MT, a protective film PF is formed on the surface inside chamber 10 before etching film EF with hydrogen fluoride. The protective film PF is made of the same material as that of mask MK, and is therefore difficult to etch. Therefore, method MT makes it possible to more effectively protect the surface inside chamber 10 from reactive species. As a result, corrosion of the surface of chamber 10 caused by etching in step STc is suppressed. In turn, changes over time in the process (step STc) are suppressed. Furthermore, according to method MT, the surface inside chamber 10 is protected by the protective film PF, so that the surface of chamber 10 is made sputter-resistant, and particles of the material constituting the surface of chamber 10 are suppressed from scattering.

[0071] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. In addition, elements in different embodiments can be combined to form other embodiments.

[0072] For example, the plasma processing apparatus used to perform the method MT may be a capacitively coupled plasma processing apparatus different from the plasma processing apparatus 1. The plasma processing apparatus used to perform the method MT may be a type of plasma processing apparatus different from the capacitively coupled type. Such a plasma processing apparatus is, for example, an inductively coupled plasma processing apparatus, an electron cyclotron resonance (ECR) plasma processing apparatus, or a plasma processing apparatus that generates plasma from a gas by surface waves such as microwaves.

[0073] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0074] Reference Signs List 1: plasma processing apparatus, 10: chamber, 61: high frequency power supply, 62: bias power supply, GS: gas supply unit, 80: control unit, W: substrate, EF: film, MK: mask.

Claims

1. A chamber; a substrate support within the chamber; a plasma generating unit configured to generate a plasma from a gas in the chamber; A control unit; Equipped with The control unit is (a) providing a substrate on the substrate support with a surface of the chamber coated with a metal-containing material, the substrate having a silicon-containing film and a metal-containing mask on the silicon-containing film; (b) etching the silicon-containing film with a plasma generated in the chamber with the surface covered with the metal-containing material using an etching gas comprising hydrogen fluoride; configured to perform a process including Plasma processing equipment.

2. 2. The plasma processing apparatus of claim 1, wherein the metal-containing mask comprises titanium, titanium nitride, titanium carbide, titanium oxide, tungsten, tungsten carbide, ruthenium, ruthenium oxide, molybdenum, or molybdenum carbide.

3. 3. The plasma processing apparatus according to claim 1, wherein the control unit is configured to perform a process of covering the surface of the chamber with the metal-containing material by chemical vapor deposition, metal-organic chemical vapor deposition, or atomic layer deposition using a film-forming gas before (a).

4. The deposition gas is WF ６ , TiCl ４ , C ８ H ２４ N ４ Ti, RuCl ３ , or MoCl ５ The plasma processing apparatus of claim 3 .

5. 5. The plasma processing apparatus of claim 1, wherein the control unit is configured to execute a process including a step of dry cleaning the inside of the chamber after the step (b).

6. The plasma processing apparatus according to claim 5 , wherein the control unit is configured to execute the dry cleaning step so as to remove reaction products deposited on the metal-containing material covering the surface of the chamber together with at least a portion of the metal-containing material.

7. The plasma processing apparatus according to claim 5 , wherein the control unit is configured to execute the dry cleaning step in a state where a dummy substrate is placed on the substrate support.

8. 7. The plasma processing apparatus according to claim 5, wherein the control unit is configured to execute the dry cleaning step in a state where a dummy substrate is not placed on the substrate support.

9. The dry cleaning is performed by NF ３ , Cl ２ , BCl ３ , SiCl ４ , O ２ , C.H. ３ OH or C ２ H ５ The plasma processing apparatus according to any one of claims 5 to 8, wherein the plasma processing is carried out using a cleaning gas containing OH.

10. 10. The plasma processing apparatus according to claim 1, wherein the etching gas further contains a phosphorus-containing gas.

11. A chamber; a substrate support within the chamber; a plasma generating unit configured to generate a plasma from a gas in the chamber; A control unit; Equipped with The control unit is (a) providing a substrate on the substrate support with a surface of the chamber coated with a metal-containing material, the substrate having a silicon-containing film and a metal-containing mask on the silicon-containing film; (b) etching the silicon-containing film in the chamber with the surface coated with the metal-containing material using a plasma generated from an etching gas comprising a fluorine-containing gas and a hydrogen-containing gas; configured to perform a process including Plasma processing equipment.

12. The plasma processing apparatus according to claim 11 , wherein in the step (b), the silicon-containing film is etched with hydrogen fluoride generated from the etching gas.

13. The fluorine-containing gas is CF ４ , C ４ F ８ , C ４ F ６ , C ３ F ８ , C ５ F ８ , S.F. ６ , N.F. ３ , XeF ２ , P.F. ３ , P.F. ５ , C.F. ３ I.C. ２ F ５ I.C. ３ F ７ I, IF ５ , I.F. ７ , W.F. ６ , HF and SiF ４ The plasma processing apparatus according to claim 11 , comprising at least one selected from the group consisting of:

14. The hydrogen-containing gas is H ２ , C.H. ４ , C.H. ２ F ２ , C.H. ３ F, C.H.F. ３ , H ２ The plasma processing apparatus according to claim 11 or 13, comprising at least one selected from the group consisting of O, HF, HCl, HBr, and HI.

15. The plasma processing apparatus according to any one of claims 11 to 14, wherein the control unit is configured to perform a process of covering the surface of the chamber with the metal-containing material by chemical vapor deposition, metal-organic chemical vapor deposition, or atomic layer deposition using a film-forming gas before (a).

16. 16. The plasma processing apparatus of claim 11, wherein the control unit is configured to execute a process including a step of dry cleaning the inside of the chamber after the step (b).

17. The plasma processing apparatus of claim 16 , wherein the control unit is configured to execute the dry cleaning step to remove reaction products deposited on the metal-containing material covering the surface of the chamber together with at least a portion of the metal-containing material.

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