Etching method, substrate processing apparatus, and substrate processing system

Abstract

An etching method, a substrate processing apparatus, and a substrate processing system are provided that can improve the selectivity of etching of a region within a substrate relative to etching of a mask and improve the verticality of an opening formed in the region. An example embodiment etching method includes a step of forming a film on a surface of a substrate. The substrate has a region formed at least partially of silicon oxide and a mask. The mask is formed on the region of the substrate and provides an opening that partially exposes the region. The film is formed of a material of the same kind as a material of the region of the substrate. The film is formed in a manner that can correct a shape of a sidewall surface of the prescribed opening to a vertical shape. The etching method also includes a step of etching the region of the substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to an etching method, a substrate processing apparatus, and a substrate processing system. BACKGROUND

[0002] In order to form an opening in a film within a substrate, plasma etching can be used. Patent Literature 1 discloses plasma etching of a silicon oxide film. The silicon oxide film is etched with chemical species of a plasma formed from a fluorocarbon gas. In the etching of the silicon oxide film, the fluorocarbon is deposited on a side wall surface of a prescribed opening, and etching in a lateral direction of the silicon oxide film is suppressed.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2019-050305 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a technique for improving the selectivity of etching of a region within a substrate with respect to etching of a mask, and improving the verticality of an opening formed in the region.

[0008] MEANS OF SOLVING THE PROBLEMS

[0009] In one illustrative embodiment, an etching method is provided. The etching method includes a step of forming a film on a surface of a substrate. The substrate has a region formed at least partially of silicon oxide and a mask. The mask is formed on the region of the substrate and provides an opening that partially exposes the region. The film is formed of a material of the same kind as a material of the region of the substrate. The etching method also includes a step of etching the region of the substrate. The film corrects a shape of the mask so that the verticality of an opening formed in the region is improved in the step of etching the region.

[0010] EFFECTS OF THE INVENTION

[0011] According to one illustrative embodiment, the selectivity of etching of a region within a substrate with respect to etching of a mask can be improved, and the verticality of an opening formed in the region can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a flowchart of an etching method of one illustrative embodiment.

[0013] Figure 2 FIG. 2 is a partially enlarged cross-sectional view of a substrate of one example.

[0014] Figure 3FIG. 1 is a diagram schematically showing a substrate processing apparatus according to an embodiment.

[0015] Figure 4 FIG. 2 is an enlarged sectional view of an electrostatic chuck in the substrate processing apparatus according to an embodiment.

[0016] Figure 5 FIG. 3 is a flowchart of a film forming method that can be used in an etching method according to an embodiment.

[0017] Figure 6 (a) of FIG. 4 is a partial enlarged sectional view of a substrate in a state after a precursor layer is formed. Figure 6 (b) of FIG. 4 is a partial enlarged sectional view of a substrate in a state after a film PF is formed.

[0018] Figure 7 (a) of FIG. 5 is a diagram for explaining Figure 1 a step ST2 of the etching method shown in FIG. 5, Figure 7 (b) of FIG. 5 is a partial enlarged sectional view of a substrate in a state after the step ST2 is performed.

[0019] Figure 8 FIG. 6 is a diagram showing a substrate processing system according to an embodiment.

[0020] BRIEF DESCRIPTION OF DRAWINGS

[0021] 1... plasma processing apparatus; 10... chamber; 16... substrate support; GS... gas supply section; 80... control section; W... substrate; RE... region; MK... mask. DETAILED DESCRIPTION

[0022] Hereinafter, various embodiments will be described.

[0023] In an embodiment, an etching method is provided. The etching method includes a step of forming a film on a surface of a substrate. The substrate has a region formed at least partially of silicon oxide and a mask. The mask is formed on the region of the substrate and provides an opening that partially exposes the region. The film is formed of a material of the same kind as a material of the region of the substrate. The etching method also includes a step of etching the region of the substrate. The film modifies a shape of the mask so that a verticality of the opening formed in the region in the step of etching the region is improved.

[0024] In the etching method of the above embodiment, the film formed on the substrate protects the mask at the start of etching of the region. Therefore, according to the etching method of the above embodiment, a selectivity of etching of the region of the substrate relative to etching of the mask can be improved. Furthermore, since the shape of the mask is modified by the film, the verticality of the opening formed in the region by etching is improved.

[0025] In one illustrative embodiment, the film can be formed so that its thickness decreases in a depth direction of the opening from an upper end of the substrate.

[0026] In one illustrative embodiment, the step of forming the film and the step of etching the region can be alternately repeated.

[0027] In one illustrative embodiment, the step of forming the film can include a step of forming a precursor layer on the substrate by supplying a first gas to the substrate, and a step of forming the film from the precursor layer by supplying a second gas to the precursor layer.

[0028] In one illustrative embodiment, the region of the substrate can include a silicon oxide film. In one illustrative embodiment, the region of the substrate can include one or more silicon oxide films and one or more silicon nitride films alternately stacked. In one illustrative embodiment, the region of the substrate can include one or more silicon oxide films and one or more polysilicon films alternately stacked. In one illustrative embodiment, the region of the substrate can include one or more silicon oxide films, one or more silicon nitride films, and one or more polysilicon films stacked.

[0029] In one illustrative embodiment, the mask can be formed of silicon, a carbon-containing material, or a metal-containing material.

[0030] In another illustrative embodiment, a substrate processing apparatus is provided. The substrate processing apparatus includes a chamber, a gas supply portion, and a control portion. The gas supply portion is capable of supplying a gas into the chamber. The control portion controls the gas supply portion to supply the gas into the chamber to form a film on a substrate. The substrate has a region formed at least partially of silicon oxide and a mask. The film is formed of a material of the same kind as a material of the region of the substrate. The film is formed in a manner that enables to improve a verticality of an opening formed in the region by etching by modifying a shape of the mask. The control portion controls the gas supply portion to supply the gas into the chamber to etch the region of the substrate.

[0031] In yet another illustrative embodiment, a substrate processing system is provided. The substrate processing system includes a film forming apparatus and a substrate processing apparatus. The film forming apparatus is capable of forming a film on a substrate. The substrate has a region formed at least partially of silicon oxide and a mask. The film is formed of a material of the same kind as a material of the region of the substrate. The film is formed in a manner that enables to improve a verticality of an opening formed in the region by etching by modifying a shape of the mask. The substrate processing apparatus is capable of etching the region of the substrate.

[0032] Next, various exemplary embodiments will be described in detail with reference to the drawings. Furthermore, the same or corresponding portions will be denoted by the same reference numerals in each drawing.

[0033] Figure 1 is a flowchart of an etching method of an exemplary embodiment. The etching method shown in Figure 1 is executed to etch a region in a substrate. Figure 2 is a partially enlarged sectional view of a substrate of an example. Figure 2 The substrate W shown in has a region RE and a mask MK. The substrate W can also have a base region UR.

[0034] The region RE is a region to be etched in the method MT. In the method MT, the region RE is etched. Figure 2 In the substrate W shown in, the region RE is formed on the base region UR. The mask MK is formed on the region RE. The mask MK is patterned. That is, the mask MK provides one or more openings OP that partially expose the region RE. The width of the opening OP provided by the mask MK can be, for example, 100 nm or less.

[0035] The region RE is at least partially formed of silicon oxide. In the first example of the substrate W, the region RE can also include a silicon oxide film. In the first example of the substrate W, the region RE can also be formed of one silicon oxide film. In the second example of the substrate W, the region RE can also include one or more silicon oxide films and one or more silicon nitride films that are alternately stacked. In the second example of the substrate W, the region RE can also include one silicon oxide film and one silicon nitride film. One silicon nitride film can be provided between one silicon oxide film and the mask MK. In the third example of the substrate W, the region RE can also include one or more silicon oxide films and one or more polysilicon films that are alternately stacked. In the fourth example of the substrate W, the region RE can also include one or more silicon oxide films, one or more silicon nitride films, and one or more polysilicon films that are stacked.

[0036] The mask MK can be formed of any material as long as the region RE can be selectively etched with respect to the mask MK in the step ST2 described later. The mask MK can be formed of silicon, a carbon-containing material, or a metal-containing material. The silicon included in the mask MK is, for example, polysilicon or amorphous silicon. The carbon-containing material included in the mask MK is, for example, amorphous carbon or spin-on carbon material. The metal-containing material included in the mask MK is, for example, tungsten, tungsten carbide, or titanium nitride.

[0037] In one embodiment, the method MT is executed using a substrate processing apparatus. Figure 3 is a diagram that schematically shows a substrate processing apparatus of an exemplary embodiment. Figure 3 The substrate processing apparatus shown in is a capacitively coupled type plasma processing apparatus 1.

[0038] The plasma processing apparatus 1 has a chamber 10. The chamber 10 is provided with an internal space 10s therein. A central axis of the chamber 10 is an axis AX extending in a 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 formed of, for example, aluminum. The chamber body 12 is electrically grounded. A film having corrosion resistance is provided on an inner wall surface of the chamber body 12. The film can also be a film formed of a ceramic such as aluminum oxide, yttrium oxide, or the like.

[0039] A passage 12p is formed in a side wall of the chamber body 12. The substrate W passes through the passage 12p when the substrate W is transported between the internal space 10s and the outside of the chamber 10. The passage 12p is openable and closable by a gate valve 12g. The gate valve 12g is provided along the side wall of the chamber body 12.

[0040] The plasma processing apparatus 1 also has a substrate support 16. The substrate support 16 is capable of supporting the substrate W within the chamber 10. The substrate W can have a substantially disc shape. The substrate support 16 is supported by a support body 15. The support body 15 extends upward from a bottom of the chamber body 12. The support body 15 has a substantially cylindrical shape. The support body 15 is formed of an insulating material such as quartz.

[0041] The substrate support 16 includes a lower electrode 18 and an electrostatic chuck 20. The substrate support 16 can also include an electrode plate 19. The electrode plate 19 is formed of an electrically conductive material such as aluminum. The electrode plate 19 has a substantially disc shape with a central axis being the axis AX. The lower electrode 18 is provided on the electrode plate 19. The lower electrode 18 is formed of an electrically conductive material such as aluminum. The lower electrode 18 has a substantially disc shape with a central axis being the axis AX. The lower electrode 18 is electrically connected to the electrode plate 19.

[0042] A flow path 18f is formed in an inside of the lower electrode 18. The flow path 18f is a flow path for a heat exchange medium such as a refrigerant. The flow path 18f is connected to a supply device (e.g., a cooling unit) for the heat exchange medium. The supply device is provided outside the chamber 10. The flow path 18f is supplied with the heat exchange medium from the supply device via a pipe 23a. The heat exchange medium supplied to the flow path 18f is returned to the supply device via a pipe 23b. The supply device for the heat exchange medium constitutes a temperature adjusting mechanism of the plasma processing apparatus 1.

[0043] Figure 4 Fig. 1 is a schematic view of a substrate processing apparatus according to an embodiment of the present application. Fig. 2 is a schematic view of a substrate processing apparatus according to another embodiment of the present application. Fig. 3 is a schematic view of a substrate processing apparatus according to another embodiment of the present application. Fig. 4 is a schematic view of a substrate processing apparatus according to another embodiment of the present application. Figure 3 Fig. 5 is a schematic view of a substrate processing apparatus according to another embodiment of the present application. Figure 4An electrostatic chuck 20 is provided on the lower electrode 18. The substrate W can be placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body 20m and an electrode 20e. The main body 20m is formed of a dielectric. The electrostatic chuck 20 and the main body 20m each have a substantially disc shape with the central axis as the axis AX. The electrode 20e is a film-like electrode provided in the main body 20m. The electrode 20e is connected to a direct current power source 20p via a switch 20s. When a voltage from the direct current power source 20p is applied to the electrode 20e, electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. The substrate W is attracted to the electrostatic chuck 20 by the generated electrostatic attraction and is held by the electrostatic chuck 20.

[0044] The substrate support 16 can have one or more heaters HT. The one or more heaters HT can each be a resistive heating element. The plasma processing apparatus 1 can also have a heater controller HC. The one or more heaters HT each generate heat in response to electric power applied from the heater controller HC. As a result, the temperature of the substrate W on the substrate support 16 can be adjusted. The one or more heaters HT constitute a temperature adjustment mechanism of the plasma processing apparatus 1. In one embodiment, the substrate support 16 has a plurality of heaters HT. The plurality of heaters HT can also be provided in the electrostatic chuck 20.

[0045] An edge ring ER is disposed on the peripheral portion of the substrate support 16 in a manner to surround the edge of the substrate W. The substrate W is disposed on the electrostatic chuck 20 and in the area surrounded by the edge ring ER. The edge ring ER serves to improve the in-plane uniformity of the plasma processing of the substrate W. The edge ring ER can be formed of silicon, silicon carbide, or quartz.

[0046] The plasma processing apparatus 1 can also have a gas supply line 25. The gas supply line 25 supplies a heat-conducting gas (e.g., He gas) from a gas supply mechanism to between the upper surface of the electrostatic chuck 20 and the back surface (lower surface) of the substrate W.

[0047] The plasma processing apparatus 1 also includes a cylindrical portion 28 and an insulating portion 29. The cylindrical portion 28 extends upward from the bottom of the chamber main body 12. The cylindrical portion 28 extends along the outer periphery of the support body 15. The cylindrical portion 28 is formed of an electrically 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, for example, 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.

[0048] The plasma processing apparatus 1 also has an upper electrode 30. The upper electrode 30 is provided above the substrate support 16. The upper electrode 30 is supported to an upper portion of the chamber main body 12 via a member 32. The member 32 is formed of a material having insulating property. The upper electrode 30 and the member 32 close an upper opening of the chamber main body 12.

[0049] The upper electrode 30 can include a top plate 34 and a support body 36. A lower surface of the top plate 34 is a lower surface on the inner space 10s side, which defines the inner space 10s. The top plate 34 is formed of a conductor or a semiconductor having low electric resistance and less Joule heat. In one embodiment, the top plate 34 is formed of silicon. A plurality of gas release holes 34a are formed in the top plate 34. The plurality of gas release holes 34a penetrate the top plate 34 in a plate thickness direction of the top plate 34.

[0050] The support body 36 supports the top plate 34 in a detachable manner. The support body 36 is formed of an electrically conductive material such as aluminum. A gas diffusion chamber 36a is provided in the inside of the support body 36. A plurality of gas holes 36b are formed in the support body 36. The plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b respectively communicate with the plurality of gas release holes 34a. A gas introduction port 36c is formed in the support body 36. The gas introduction port 36c is connected to the gas diffusion chamber 36a. The gas introduction port 36c is connected to a gas supply pipe 38.

[0051] The gas supply pipe 38 is connected to a gas source group 40 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 section GS. The gas source group 40 includes a plurality of gas sources. The plurality of gas sources of the gas source group 40 include sources of a plurality of gases used in the method MT. In a case where one or more gases used in the method MT are formed of a liquid, the plurality of gas sources include one or more gas sources each having a liquid source and a vaporizer. The valve group 41 and the valve group 43 each include a plurality of on-off valves. The flow rate controller group 42 includes a plurality of flow rate controllers. The plurality of flow rate controllers of the flow rate controller group 42 are each a mass flow rate controller or a pressure control type flow rate controller. The plurality of gas sources of the gas source group 40 are each connected to the gas supply pipe 38 via a corresponding on-off valve of the valve group 41, a corresponding flow rate controller of the flow rate controller group 42, and a corresponding on-off valve of the valve group 43.

[0052] The plasma processing apparatus 1 also has a baffle member 48. The baffle member 48 is provided between the cylindrical portion 28 and the side wall of the chamber body 12. The baffle member 48 can be a plate-like member. The baffle member 48 is constituted, for example, by forming a film having corrosion resistance on the surface of a member formed of aluminum. The film having corrosion resistance can be a film formed of a ceramic such as yttrium oxide. A plurality of through-holes are formed in the baffle member 48. An exhaust port 12e is provided below the baffle member 48 and the bottom of the chamber body 12. The exhaust port 12e is connected to an exhaust device 50 via an exhaust pipe 52. The exhaust device 50 has a pressure regulating valve and a vacuum pump such as a turbo molecular pump.

[0053] The plasma processing apparatus 1 also includes a high-frequency power source 61. The high-frequency power source 61 is a power source that generates high-frequency electric power HF for generating plasma. The high-frequency electric power HF has a first frequency. The first frequency is, for example, a frequency in the range of 27 to 100 MHz. The high-frequency power source 61 is connected to the lower electrode 18 via a matcher 61m and the electrode plate 19 to supply the high-frequency electric power HF to the lower electrode 18. The matcher 61m has a matching circuit. The matching circuit of the matcher 61m has a variable impedance. The impedance of the matching circuit of the matcher 61m can be adjusted to reduce reflection from the load of the high-frequency power source 61. Further, the high-frequency power source 61 can also be connected to the upper electrode 30 via the matcher 61m instead of being electrically connected to the lower electrode 18. The high-frequency power source 61 constitutes one example of a plasma generating portion.

[0054] The plasma processing apparatus 1 also has a bias power source 62. The bias power source 62 generates bias electric power BP for attracting ions to the substrate W. The bias power source 62 is connected to the lower electrode 18 via the electrode plate 19.

[0055] In one embodiment, the bias power source 62 can be a high-frequency power source that generates high-frequency electric power LF as the bias electric power BP. The high-frequency electric power LF has a second frequency that is suitable for attracting ions in plasma to the substrate W. The second frequency can be a frequency lower than the first frequency. The second frequency is, for example, a frequency in the range of 400 kHz to 13.56 MHz. In this embodiment, the bias power source 62 is connected to the lower electrode 18 via a matcher 62m and the electrode plate 19. The matcher 62m has a matching circuit. The matching circuit of the matcher 62m has a variable impedance. The impedance of the matching circuit of the matcher 62m can be adjusted to reduce reflection from the load of the bias power source 62.

[0056] Further, the plasma can also be generated using only one of the high-frequency power source 61 and the bias power source 62. In this case, one power source constitutes a plasma generating section of one example. In this case, the frequency of the high-frequency electric power supplied from the one power source is a frequency larger than 13.56 MHz, for example, 40 MHz. In this case, the plasma processing apparatus can also not have the other one of the high-frequency power source 61 and the bias power source 62.

[0057] In another embodiment, the bias power source 62 can be a direct-current power source device that intermittently applies pulses of a direct-current voltage of a negative polarity as the bias electric power BP to the lower electrode 18. For example, the bias power source 62 can periodically apply pulses of a direct-current voltage of a negative polarity to the lower electrode 18 at a period defined by a frequency in the range of 1 kHz to 1 MHz.

[0058] In one embodiment, the plasma processing apparatus 1 can also have a direct-current power source device 64. The direct-current power source device 64 is connected to the upper electrode 30. The direct-current power source device 64 is capable of applying a direct-current voltage, for example, a direct-current voltage of a negative polarity to the upper electrode 30. The direct-current power source device 64 can intermittently or periodically apply pulses of a direct-current voltage to the upper electrode 30.

[0059] In the case where the plasma is generated in the plasma processing apparatus 1, a gas is supplied from the gas supply section GS to the internal space 10s. Further, by supplying the high-frequency electric power, a high-frequency electric field is generated between the upper electrode 30 and the lower electrode 18. The gas is excited by the generated high-frequency electric field. As a result, the plasma is generated in the chamber 10.

[0060] The plasma processing apparatus 1 also includes a control section 80. The control section 80 is a computer having a processor, a storage device, an input device, a display device, and the like, and controls the sections of the plasma processing apparatus 1. Specifically, the control section 80 executes a control program stored in the storage device, and controls the sections of the plasma processing apparatus 1 based on recipe data stored in the storage device. By the control of the control section 80, the processing specified by the recipe data is executed in the plasma processing apparatus 1. By the control of the sections of the plasma processing apparatus 1 by the control section 80, the method MT is executed in the plasma processing apparatus 1.

[0061] Referring again to Figure 1 The method MT will be described in detail. In the following description, a case where the substrate W shown in FIG. 1 is processed using the plasma processing apparatus 1 will be taken as an example, and the method MT will be described. Further, in the method MT, other substrate processing apparatuses can also be used. In the method MT, other substrates can also be processed. Figure 2 The method MT will be described in detail. In the following description, a case where the substrate W shown in FIG. 1 is processed using the plasma processing apparatus 1 will be taken as an example, and the method MT will be described. Further, in the method MT, other substrate processing apparatuses can also be used. In the method MT, other substrates can also be processed.

[0062] Method MT is performed with the substrate W placed on the substrate support 16. Method MT can be performed while maintaining a depressurized environment in the internal space of the chamber 10 for 10 seconds and without removing the substrate W from the internal space for 10 seconds.

[0063] Method MT includes steps ST1 and ST2. In step ST1, film PF is formed on the surface of substrate W (refer to...). Figure 6 (b) In step ST2, region RE is etched. Film PF is formed of the same type of material as region RE. While region RE is being etched in step ST2, film PF is simultaneously etched. In one embodiment, the etching rate of film PF in step ST2 can be greater than or equal to the etching rate of region RE. Alternatively, the value obtained by dividing the etching rate of film PF by the etching rate of region RE can be greater than or equal to 0.7 and less than 1.2. In one embodiment, film PF is formed of silicon oxide such as TEOS.

[0064] The membrane PF formed in step ST1 modifies the shape of the mask MK in a way that improves the perpendicularity of the opening formed in region RE in step ST2. The membrane PF enables the mask MK to have a tapered shape (see reference). Figure 2 It is formed in a gentle manner. In step ST1, the membrane PF can be formed as follows: Figure 6 As shown in (b), the shape of the sidewall surface SS of the specified opening OP is (refer to) Figure 2 The film PF is formed in a manner that corrects to a vertical shape. In one embodiment, the film PF is formed such that its thickness decreases from the top end of the substrate W along the depth direction of the opening OP.

[0065] The PF film can also be formed in step ST1 by CVD. The CVD method can be plasma-enhanced CVD or thermal CVD. In step ST1 using the CVD method, a film-forming gas is supplied to chamber 10. In step ST1 using the CVD method, plasma can also be generated from the film-forming gas within chamber 10. The film-forming gas includes silicon-containing gas and oxygen-containing gas. For example, the silicon-containing gas is SiCl4 gas. For example, the oxygen-containing gas is O2 gas.

[0066] In step ST1 of the CVD method, the control unit 80 controls the gas supply unit GS to supply film-forming gas into the chamber 10. Furthermore, the control unit 80 controls the exhaust device 50 to set the pressure within the chamber 10 to a specified pressure. In ST1 of the CVD method, the control unit 80 can control the plasma generation unit to generate plasma from the film-forming gas. Specifically, the control unit 80 can control the high-frequency power supply 61 and / or the bias power supply 62 to supply high-frequency electrical power HF and / or high-frequency electrical power LF.

[0067] Alternatively, the membrane PF can also be passed through in step ST1. Figure 5 The film is formed using the method shown. Figure 5 This is a flowchart of a film formation method that can be used in an etch method according to an exemplary embodiment. Below, refer to... Figure 5 , Figure 6 (a) and Figure 6 (b) Figure 6 (a) is a partially enlarged cross-sectional view of a substrate in an example state after the precursor layer has been formed. Figure 6 (b) is a partially enlarged cross-sectional view of an example substrate in the state after the formation of the PF film.

[0068] like Figure 5 As shown, in one embodiment, step ST1 includes steps ST11 and ST13. Step ST1 may also include steps ST12 and ST14. Step ST12 is performed between steps ST11 and ST13. Step ST14 is performed between steps ST13 and ST11.

[0069] In step ST11, as Figure 6 As shown in (a), a precursor layer PC is formed on the surface of the substrate W. In step ST11, a first gas is used to form the precursor layer PC. The first gas contains substances constituting the precursor layer PC. The first gas can be an oxygen-containing silicon gas. The first gas, for example, contains an aminosilane gas. In step ST11, the precursor layer PC may also be formed without generating plasma from the first gas. Alternatively, in step ST11, the precursor layer PC may also be formed using a chemical species derived from plasma generated from the first gas.

[0070] In step ST11, the control unit 80 controls the gas supply unit GS to supply the first gas into the chamber 10. In step ST11, the control unit 80 controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a specified pressure. If plasma is generated in step ST11, the control unit 80 controls the plasma generation unit to generate plasma from the first gas within the chamber 10. In one embodiment, to generate plasma from the first gas, the control unit 80 controls the high-frequency power supply 61 and / or the bias power supply 62 to supply high-frequency electrical power HF and / or high-frequency electrical power LF.

[0071] In order to Figure 6In the case of the condition (1), the pressure of the gas in the chamber 10 at the time of execution of the step ST11 is set to a pressure lower than the pressure at which the substance forming the precursor layer PC is adsorbed on the entire surface of the substrate W in the case where the other processing conditions are the same. In the case of the condition (2), the processing time of the step ST11 is set to a time shorter than the processing time at which the substance forming the precursor layer PC is adsorbed on the entire surface of the substrate W in the case where the other processing conditions are the same. In the case of the condition (3), the dilution degree of the first gas of the substance forming the precursor layer PC is set to a value higher than the dilution degree at which the substance forming the precursor layer PC is adsorbed on the entire surface of the substrate W in the case where the other processing conditions are the same. In the case of the condition (4), the temperature of the substrate support 16 at the time of execution of the step ST11 is set to a temperature lower than the temperature at which the substance forming the precursor layer PC is adsorbed on the entire surface of the substrate W in the case where the other processing conditions are the same. The condition (5) can be applied in the case where the plasma is generated in the step ST11. In the case of the condition (5), the absolute value of the high-frequency electric power (the high-frequency electric power HF and / or the high-frequency electric power LF) is set to a value smaller than the absolute value at which the substance forming the precursor layer PC is adsorbed on the entire surface of the substrate W in the case where the other processing conditions are the same.

[0072] In the step ST12, the purge of the internal space 10s is performed. In the step ST12, the control section 80 controls the exhaust device 50 to perform the exhaust of the internal space 10s. In the step ST12, the control section 80 can also control the gas supply section GS to supply the non-reactive gas into the chamber 10. By performing the step ST12, the first gas in the chamber 10 can be replaced with the non-reactive gas. By performing the step ST12, the excess substance adsorbed on the substrate W can be removed.

[0073] In the step ST13, the film PF is formed from the precursor layer PC, as shown in (b) of FIG. 1. Figure 6 In the step ST13, the film PF is formed from the precursor layer PC, as shown in (b) of FIG. 1.

[0074] In step ST13, the control unit 80 controls the gas supply unit GS to supply the second gas into the chamber 10. In step ST13, the control unit 80 controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a specified pressure. If plasma is generated in step ST13, the control unit 80 controls the plasma generation unit to generate plasma from the second gas within the chamber 10. In one embodiment, to generate plasma from the second gas, the control unit 80 controls the high-frequency power supply 61 and / or the bias power supply 62 to supply high-frequency electrical power HF and / or high-frequency electrical power LF.

[0075] In order to form Figure 6 The membrane PF shown in (b) may also satisfy at least one of the conditions (1) to (5) in step ST13. Under condition (1), the pressure of the gas in chamber 10 during step ST13 is set to a pressure lower than the pressure at which the reaction between the substance in the second gas and the substance forming the precursor layer PC is completed throughout the precursor layer PC under the same processing conditions. Under condition (2), the processing time of step ST13 is set to a time shorter than the processing time at which the reaction between the substance in the second gas and the substance forming the precursor layer PC is completed throughout the precursor layer PC under the same processing conditions. Under condition (3), the dilution of the substance forming the membrane PF in the second gas is set to a value higher than the dilution at which the reaction between the substance in the second gas and the substance forming the precursor layer PC is completed throughout the precursor layer PC under the same processing conditions. Under condition (4), the temperature of substrate support 16 during step ST13 is set to a temperature lower than the temperature at which the reaction between the substance in the second gas and the substance forming the precursor layer PC is completed throughout the precursor layer PC under the same processing conditions. The condition (5) can be applied to the case where plasma is generated in step ST13. Under the condition (5), the absolute value of the high-frequency electric power (high-frequency electric power HF and / or high-frequency electric power LF) is set to be smaller than the absolute value of the reaction between the substances in the second gas and the substances forming the precursor layer PC under the same other processing conditions.

[0076] In step ST14, the internal space is purged for 10 seconds. Step ST14 is the same as step ST12. By performing step ST14, the second gas in chamber 10 can be replaced with an inactive gas.

[0077] In step ST1, a plurality of film formation cycles CY1 each including steps ST11 and ST13 can be repeated sequentially. Each of the plurality of film formation cycles CY1 can also include steps ST12 and ST14. The thickness of the film PF can be adjusted with the number of repetitions of the film formation cycle CY1. In the case where the film formation cycle CY1 is repeated, it is determined in step ST15 whether a stop condition is satisfied. The stop condition is satisfied in the case where the number of executions of the film formation cycle CY1 reaches a prescribed number. In the case where it is determined in step ST15 that the stop condition is not satisfied, the film formation cycle CY1 is executed again. In the case where it is determined in step ST15 that the stop condition is satisfied, the execution of step ST1 ends, and the process proceeds to step ST2 as shown in Figure 1

[0078] After the film PF is formed on the substrate W in step ST1, step ST2 is executed. In step ST2, the region RE is etched. In one embodiment, the region RE is etched by chemical species from the plasma. In step ST2, the plasma P2 is generated from a process gas in the chamber 10.

[0079] The process gas used in step ST2 includes a fluorocarbon gas in the case where the region RE is formed of a silicon oxide film. In each of the second to fourth examples of processing the substrate W, the process gas used in step ST2 includes a fluorocarbon gas and / or a hydrofluorocarbon gas. In addition, in the case where the substrate W of any of the examples is processed, the process gas used in step ST2 can also include a non-reactive gas (e.g., a noble gas).

[0080] Figure 7 (a) of FIG. 8 is a view for explaining an example of step ST2 of the etching method shown in Figure 1 Figure 7 (b) is a partial enlarged sectional view of a substrate in a state after step ST2 is executed. In step ST2, as shown in Figure 7 (a) of FIG. 8, chemical species from the plasma P2 are irradiated to the region RE, and the region RE is etched by the chemical species. As a result of executing step ST2, as shown in Figure 7 (b) of FIG. 8, the depth of the opening OP is increased. In the region RE, the opening OP has an aspect ratio of 10 or more.

[0081] ​​In step ST2, the control section 80 controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a prescribed pressure. In step ST2, the control section 80 controls the gas supply section GS to supply a processing gas into the chamber 10. In step ST2, the control section 80 controls the plasma generation section to generate a plasma from the processing gas. In step ST2 of one embodiment, the control section 80 controls the high-frequency power supply 61 and the bias power supply 62 to supply the high-frequency electric power HF and the bias electric power BP. In step ST2, only one of the high-frequency electric power HF and the high-frequency electric power LF can be supplied for generating a plasma.

[0082] In the method MT, a plurality of cycles CY each including the step ST1 and the step ST2 can be sequentially performed. In the case where the plurality of cycles CY are sequentially performed, it is determined in step ST3 whether a stop condition is satisfied. The stop condition is satisfied in the case where the number of times of execution of the film formation cycle CY reaches a prescribed number of times. In the case where it is determined in step ST3 that the stop condition is not satisfied, the film formation cycle CY is executed again. In the case where it is determined in step ST3 that the stop condition is satisfied, the execution of the method MT is ended.

[0083] In the method MT, the film PF formed on the substrate W protects the mask MK at the start of etching of the region RE. Therefore, according to the method MT, the selectivity of etching of the region RE with respect to etching of the mask MK can be improved. Further, since the shape of the mask MK is corrected by the film PF, the verticality of an opening formed in the region RE by etching is made higher.

[0084] In addition, the conditions of the step ST1 for forming the film PF in at least one of the plurality of cycles CY can be different from the conditions of the step ST1 for forming the film PF in at least another of the plurality of cycles CY. The conditions of the step ST1 of all the cycles CY can be different from each other. In this case, in each cycle, the film PF can be formed to have a thickness or a coverage range different from that of the film PF formed in another cycle.

[0085] The conditions of the step ST2 for etching the region RE in at least one of the plurality of cycles CY can be different from the conditions of the step ST2 for etching the region RE in at least another of the plurality of cycles CY. The conditions of the step ST2 of all the cycles CY can be different from each other. In this case, in each cycle, the region RE is etched to an etching amount different from that of the region RE in another cycle.

[0086] In each of the plurality of cycles CY, the conditions for forming the film PF in one of the plurality of film forming cycles CY1 can be different from the conditions for forming the film PF in at least another one of the plurality of film forming cycles CY1. That is, in each of the plurality of cycles CY, the conditions of the step ST11 and / or the conditions of the step ST13 in one of the film forming cycles can be different from the conditions of the step ST11 and / or the conditions of the step ST13 in at least another one of the film forming cycles. In each of the plurality of cycles CY, the conditions for forming the film PF in all of the film forming cycles CY1 are different from each other. In this case, it is possible to control the distribution of the thickness of the film PF in each of the plurality of film forming cycles CY1 included in each of the plurality of cycles CY.

[0087] Hereinafter, the method MT will be described with reference to Figure 8 The method MT can also be executed using a substrate processing system including a film forming apparatus and a substrate processing apparatus. Figure 8 FIG. 1 is a view showing a substrate processing system PS according to an example embodiment. Figure 8 The substrate processing system PS shown in FIG. 1 can be used to execute the method MT.

[0088] The substrate processing system PS includes stages 2a to 2d, containers 4a to 4d, a load block LM, an aligner AN, load lock blocks LL1, LL2, processing blocks PM1 to PM6, a transfer block TF, and a control section MC. Further, the number of stages, the number of containers, and the number of load lock blocks in the substrate processing system PS can be any number of one or more. Further, the number of processing blocks in the substrate processing system PS can be any number of two or more.

[0089] The stages 2a to 2d are arranged along one side of the load block LM. The containers 4a to 4d are each mounted on the stages 2a to 2d, respectively. Each of the containers 4a to 4d is, for example, a container called a FOUP (Front Opening Unified Pod). Each of the containers 4a to 4d can accommodate a substrate W inside thereof.

[0090] The load block LM has a chamber. The pressure inside the chamber of the load block LM is set to be atmospheric pressure. The load block LM has a transfer device TU1. The transfer device TU1 is, for example, a multi-joint robot, and can be controlled by the control section MC. The transfer device TU1 can transfer the substrate W via the chamber of the load block LM. The transfer device TU1 can transfer the substrate W between each of the containers 4a to 4d and the aligner AN, between the aligner AN and each of the load lock blocks LL1, LL2, and between each of the load lock blocks LL1, LL2 and each of the containers 4a to 4d. The aligner AN is connected to the load block LM. The aligner AN can perform adjustment (correction) of the position of the substrate W.

[0091] Each of the load lock blocks LL1 and LL2 is provided between the load block LM and the transfer block TF. Each of the load lock blocks LL1 and LL2 provides a preliminary decompression chamber.

[0092] The transfer block TF is connected to each of the load lock blocks LL1 and LL2 via a gate valve. The transfer block TF has a transfer chamber TC which can be decompressed. The transfer block TF has a transfer device TU2. The transfer device TU2 is, for example, a multi-joint robot arm, and is controllable by the control section MC. The transfer device TU2 can transfer the substrate W via the transfer chamber TC. The transfer device TU2 can transfer the substrate W between each of the load lock blocks LL1 and LL2 and each of the processing blocks PM1 to PM6, and between any two of the processing blocks PM1 to PM6.

[0093] Each of the processing blocks PM1 to PM6 is a device capable of performing a dedicated substrate processing. One of the processing blocks PM1 to PM6 is a film forming device. The film forming device is used to form the film PF in the step ST1. Thus, the film forming device is a device capable of performing the step ST1 using the film forming method described above. In a case where the film forming device generates plasma in the step ST1, the film forming device can be a plasma processing device 1 or another plasma processing device, or the like. In a case where the film forming device forms the film PF in the step ST1 without generating plasma, the film forming device can also not have a structure for generating plasma.

[0094] Another one of the processing blocks PM1 to PM6 is a substrate processing device such as the plasma processing device 1 or another plasma processing device. The substrate processing device is used to etch the region RE in the step ST2.

[0095] In the substrate processing system PS, the control section MC can control each section of the substrate processing system PS. The control section MC controls the film forming device to form the film PF in the step ST1. After the film PF is formed, the control section MC controls the substrate processing device to etch the region RE. The substrate processing system PS can transfer the substrate W between the processing blocks without contacting the atmosphere.

[0096] The above describes various exemplified embodiments, but is not limited to the above-described exemplified embodiments, and various additions, omissions, substitutions, and changes can be made. Furthermore, elements in different embodiments can be combined to form other embodiments.

[0097] For example, the substrate processing apparatus for carrying out the method MT can be any type of plasma processing apparatus. For example, the substrate processing apparatus for carrying out the method MT can be a plasma processing apparatus other than the plasma processing apparatus 1 of the capacitive coupling type. The substrate processing apparatus for carrying out the method MT can also be a plasma processing apparatus of the inductive coupling type, an ECR (electron cyclotron resonance) plasma processing apparatus, or a plasma processing apparatus using a surface wave such as a microwave to generate plasma. Furthermore, in the method MT, the substrate processing apparatus can also not have a plasma generation section without using plasma.

[0098] According to the above description, various embodiments of the present application are described in the present specification for the purpose of illustration, it should be understood that various changes can be made without departing from the scope and spirit of the present application. Therefore, the various embodiments disclosed in the present application are not intended to be limiting, and the true scope and spirit of the present application are given by the scope of the appended claims.

Claims

1. An etching method, characterized in that, include: The step of forming a film on the surface of a substrate having a region at least partially formed of silicon oxide and a mask disposed on the region and providing an opening that partially exposes the region, the film being formed of a material of the same kind as the material of the region; and The step of etching the area, The film modifies the shape of the mask to improve the perpendicularity of the opening formed in the region during the etching step. The two steps are performed alternately and repeatedly, with the step of forming the film performed first and the step of etching the region performed later.

2. The etching method as described in claim 1, characterized in that: The film is formed such that its thickness decreases from the top end of the substrate along the depth direction of the opening.

3. The etching method as described in claim 1 or 2, characterized in that: The steps of forming the film include: The steps of forming a precursor layer on the substrate by supplying a first gas to the substrate; and The step of forming the membrane from the precursor layer by supplying a second gas to the precursor layer.

4. The etching method as described in claim 1 or 2, characterized in that: The region contains a silicon oxide film.

5. The etching method as described in claim 1 or 2, characterized in that: The region comprises one or more silicon oxide films and one or more silicon nitride films alternately stacked.

6. The etching method as described in claim 1 or 2, characterized in that: The region comprises one or more silicon oxide films and one or more polycrystalline silicon films alternately stacked.

7. The etching method as described in claim 1 or 2, characterized in that: The region comprises one or more stacked silicon oxide films, one or more silicon nitride films, and one or more polycrystalline silicon films.

8. The etching method as described in claim 1 or 2, characterized in that: The mask is formed of silicon, carbon-containing materials, or metal-containing materials.

9. The etching method as described in claim 1 or 2, characterized in that: The etching method sequentially performs multiple cycles including the steps of forming a film and etching the region. In each of the aforementioned cycles, the membrane is formed such that its thickness or coverage differs from the thickness or coverage of the membrane formed in the other cycles.

10. A substrate processing apparatus, characterized in that, include: Chamber; A gas supply unit capable of supplying gas into the chamber; and A control unit capable of controlling the gas supply unit. The control unit controls the gas supply unit to supply gas into the chamber, such that a film of the same kind of material as the region is formed on a substrate having a region at least partially formed of silicon oxide and a mask. This film, by modifying the shape of the mask, can improve the perpendicularity of the opening formed in the region by etching. The control unit controls the gas supply unit to supply gas into the chamber to etch the area. The control unit controls the gas supply unit to alternately and repeatedly perform the formation of the film and the etching of the region in a manner that first forms the film and then etches the region.

11. A substrate processing system, characterized in that, include: A film-forming apparatus capable of forming a film of the same kind of material as the region on a substrate having a region at least partially formed of silicon oxide and a mask, wherein the film is capable of improving the verticality of the opening formed in the region by etching by modifying the shape of the mask; and A substrate processing apparatus capable of etching the area described above. The substrate processing system is configured to alternately and repeatedly perform the formation of the film and the etching of the region by first forming the film using the film forming apparatus and then etching the region using the substrate processing apparatus.

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