SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD

Abstract

To provide a technique capable of suppressing damages due to plasma.SOLUTION: There is provided a substrate processing apparatus in one exemplary embodiment. The substrate processing apparatus includes: a chamber; a board supporter provided in the chamber; a gas supply unit that is placed in the chamber and is connected to a reactive gas source containing HF gas and CxHyFz gas (x and z are integers of 1 or greater, and y is an integer of 0 or greater); and a plasma generator configured to generate plasma from reactant gases supplied into the chamber from the gas supply unit. At least a portion of the plasma-exposed portion in the chamber is composed of a conductive silicon-containing material.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY Exemplary embodiments of the present disclosure relate to substrate processing apparatus and methods. [Background technology]

[0002] For example, Patent Document 1 discloses a technique for coating the inside of a chamber for processing plasma. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-208034 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for suppressing damage caused by plasma. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, a method for manufacturing a substrate-supporting gas-liquid crystallography system includes the steps of: a chamber; a substrate support disposed in the chamber; and a gas mixture containing HF gas and C x H y F z The present invention provides a substrate processing apparatus comprising: a gas supply unit connected to a supply source of a reactive gas containing a gas (x and z are integers equal to or greater than 1, and y is an integer equal to or greater than 0); and a plasma generation unit configured to generate plasma from the reactive gas supplied from the gas supply unit into the chamber, wherein at least a portion of a portion exposed to the plasma in the chamber is made of a conductive silicon-containing material. Effect of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique for suppressing damage caused by plasma can be provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating a substrate processing apparatus 1. [Diagram 2] 2 is a diagram for explaining an example of a cross-sectional structure of a chamber body 12. FIG. [Diagram 3] 2 is a diagram showing an example of a cross-sectional structure of a substrate W. FIG. [Figure 4] 3 is a flowchart showing the present processing method. [Diagram 5] 13 is a diagram showing an example of the shape of the mask film MK after etching. FIG. [Figure 6] 11 is a diagram showing an example of a cross-sectional structure of the substrate W in step ST3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Each embodiment of the present disclosure will be described below.

[0009] In one exemplary embodiment, a substrate processing apparatus is provided. The substrate processing apparatus includes a chamber, a substrate support disposed within the chamber, and a gas mixture containing HF gas and C x H y F z The apparatus includes a gas supply unit connected to a supply source of a reactive gas containing a gas (x and z are integers of 1 or more, and y is an integer of 0 or more), and a plasma generation unit configured to generate plasma from the reactive gas supplied from the gas supply unit into the chamber, and at least a portion of the portion exposed to the plasma in the chamber is made of a conductive silicon-containing material.

[0010] In one exemplary embodiment, C is supplied to the chamber. x H y F z The flow rate of the gas is 5% by volume or more with respect to the total flow rate of the reaction gases.

[0011] In one exemplary embodiment, the interior walls of the chamber are constructed with a liner made of an electrically conductive silicon-containing material.

[0012] In one exemplary embodiment, the apparatus further comprises an upper electrode disposed opposite the substrate support, the upper electrode having a gas supply.

[0013] In one exemplary embodiment, the upper electrode includes a top plate having a plurality of gas outlet holes for supplying a reaction gas into the chamber, the top plate being made of a conductive silicon material.

[0014] In one exemplary embodiment, a power supply is provided for supplying a negative DC voltage or low frequency RF power to the chamber.

[0015] In one exemplary embodiment, a power supply is provided for supplying a negative DC voltage or low frequency RF power to the upper electrode.

[0016] In one exemplary embodiment, the sidewall defining the chamber has a gas supply.

[0017] In one exemplary embodiment, a method for processing a substrate is provided, the method comprising providing a substrate having a silicon-containing film on a substrate support in a chamber, and mixing HF gas and C x H y F z The method includes the steps of: supplying a reactive gas containing a gas (x and z are integers of 1 or more, and y is an integer of 0 or more) into a chamber; and generating a plasma from the reactive gas supplied into the chamber to etch a silicon-containing film, wherein at least a portion of a portion exposed to the plasma in the chamber is composed of a conductive silicon-containing material.

[0018] In one exemplary embodiment, C x H y F z The flow rate of the gas is 5% by volume or more with respect to the total flow rate of the reaction gases.

[0019] In one exemplary embodiment, the interior walls of the chamber are constructed with a liner made of an electrically conductive silicon-containing material.

[0020] In one exemplary embodiment, the step of generating the plasma includes providing a negative DC voltage or low frequency RF power to the chamber.

[0021] In one exemplary embodiment, a sidewall defining the chamber includes a gas supply that supplies a reactive gas into the chamber.

[0022] In one exemplary embodiment, the chamber further comprises an upper electrode disposed opposite the substrate support, the upper electrode comprising a gas supply for supplying a reactive gas into the chamber.

[0023] In one exemplary embodiment, the upper electrode includes a top plate having a plurality of gas outlet holes for supplying a reaction gas into the chamber, the top plate being made of a conductive silicon material.

[0024] In one exemplary embodiment, the step of generating the plasma includes providing a negative DC voltage or low frequency RF power to the upper electrode.

[0025] In one exemplary embodiment, C x H y F z Gas is C 4 H 2 F 6 Gas, C. 4 H 2 F 8 Gas, C. 3 H 2 F 4 Gas and C 3 H 2 F 6 The gas is at least one selected from the group consisting of gases.

[0026] In one exemplary embodiment, the reaction gas further comprises at least one selected from the group consisting of a phosphorus-containing gas, a halogen-containing gas, an oxygen-containing gas, and a nitrogen-containing gas.

[0027] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are given the same reference numerals, and duplicated explanations will be omitted. Unless otherwise specified, the positional relationship such as up, down, left, right, etc. will be described based on the positional relationship shown in the drawing. The dimensional ratio of the drawings does not indicate the actual ratio, and the actual ratio is not limited to the illustrated ratio.

[0028] <Configuration of the Substrate Processing Apparatus 1> Fig. 1 is a schematic diagram of a substrate processing apparatus 1 according to an exemplary embodiment. The substrate processing apparatus 1 shown in Fig. 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The chamber 10 includes a chamber body 12. The chamber body 12 has a generally cylindrical shape.

[0029] A passage 12p is formed in a sidewall of the chamber body 12. The substrate W is transferred between the internal space 10s and the outside of the chamber 10 through the passage 12p. The passage 12p is opened and closed by a gate valve 12g. The gate valve 12g is provided along the sidewall of the chamber body 12.

[0030] A support 13 is provided on the bottom of the chamber body 12. The support 13 is made of an insulating material. The support 13 has a generally cylindrical shape. The support 13 extends upward from the bottom of the chamber body 12 in the internal space 10s. The support 13 supports a substrate support 14. The substrate support 14 is configured to support a substrate W in the internal space 10s.

[0031] The substrate support 14 has a lower electrode 18 and an electrostatic chuck 20. The substrate support 14 may further have an electrode plate 16. The electrode plate 16 is made of a conductor such as aluminum and has a substantially disk-like shape. The lower electrode 18 is provided on the electrode plate 16. The lower electrode 18 is made of a conductor such as aluminum and has a substantially disk-like shape. The lower electrode 18 is electrically connected to the electrode plate 16.

[0032] 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 has a substantially disk shape and is formed from a dielectric material. 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 20p via a switch 20s. When a voltage from the DC power supply 20p 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. The substrate W is attracted to the electrostatic chuck 20 by the electrostatic attractive force and is held by the electrostatic chuck 20.

[0033] An edge ring 25 is disposed on the substrate support 14. The edge ring 25 is a ring-shaped member. The edge ring 25 may be made of silicon, silicon carbide, quartz, or the like. The substrate W is disposed on the electrostatic chuck 20 and within a region surrounded by the edge ring 25.

[0034] A flow path 18f is provided inside the lower electrode 18. A heat exchange medium (e.g., a refrigerant) is supplied to the flow path 18f from a chiller unit provided outside the chamber 10 via a pipe 22a. The heat exchange medium supplied to the flow path 18f is returned to the chiller unit via a pipe 22b. In the substrate processing apparatus 1, the temperature of the substrate W placed on the electrostatic chuck 20 is adjusted by heat exchange between the heat exchange medium and the lower electrode 18.

[0035] The substrate processing apparatus 1 is provided with a gas supply line 24. The gas supply line 24 supplies a heat transfer gas (for example, He gas) from a heat transfer gas supply mechanism to the gap between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0036] The substrate processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 14. 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.

[0037] 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 has a plurality of gas discharge holes 34a penetrating the top plate 34 in its plate thickness direction.

[0038] The support 36 detachably supports the top plate 34. The support 36 is made of a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support 36. The support 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are connected to the plurality of gas discharge holes 34a, respectively. A gas inlet 36c is formed in the support 36. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0039] A gas source group 40 is connected to the gas supply pipe 38 via a flow rate controller group 41 and a valve group 42. The gas supply pipe 38, the flow rate controller group 41, and the valve group 42 constitute a gas supply source. The gas supply source may further include a gas source group 40. The gas source group 40 includes a plurality of gas sources. The plurality of gas sources includes a source of a process gas. The gas source group 40 includes at least a source of HF gas and a source of C x H y F zThe gas source group 40 includes a source of gas (x and z are integers equal to or greater than 1, and y is an integer equal to or greater than 0). The flow rate controller group 41 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers in the flow rate controller group 41 is a mass flow controller or a pressure-controlled flow rate controller. The valve group 42 includes a plurality of on-off valves. Each of the plurality of gas sources in the gas source group 40 is connected to the gas supply pipe 38 via a corresponding flow rate controller in the flow rate controller group 41 and a corresponding on-off valve in the valve group 42.

[0040] In the substrate processing apparatus 1, a shield 46 is detachably provided along the inner wall surface of the chamber body 12 and the outer periphery of the support part 13. The shield 46 prevents reaction by-products from adhering to the chamber body 12. The shield 46 is formed by forming a corrosion-resistant film on the surface of a base material made of, for example, aluminum. The corrosion-resistant film may be made of a ceramic such as yttrium oxide.

[0041] A baffle plate 48 is provided between the support 13 and the side wall of the chamber body 12. The baffle plate 48 is formed, for example, by forming a corrosion-resistant film (a film of yttrium oxide or the like) on the surface of a member made of aluminum. A plurality of through holes are formed in the baffle plate 48. An exhaust port 12e is provided below the baffle plate 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 includes a pressure regulating valve and a vacuum pump such as a turbo molecular pump.

[0042] The substrate processing apparatus 1 includes a high-frequency power supply 62 and a bias power supply 64. The high-frequency power supply 62 is a power supply that generates high-frequency power HF. The high-frequency power HF has a first frequency suitable for generating plasma. The first frequency is, for example, within a range of 27 MHz to 100 MHz. The high-frequency power supply 62 is connected to the lower electrode 18 via a matching device 66 and the electrode plate 16. The matching device 66 has a circuit for matching the impedance of the load side (lower electrode 18 side) of the high-frequency power supply 62 to the output impedance of the high-frequency power supply 62. The high-frequency power supply 62 may be connected to the upper electrode 30 via the matching device 66. The high-frequency power supply 62 constitutes an example of a plasma generating unit.

[0043] The bias power supply 64 is a power supply that generates an electric bias. The bias power supply 64 is electrically connected to the lower electrode 18. The electric bias has a second frequency. The second frequency is lower than the first frequency. The second frequency is, for example, a frequency within a range of 400 kHz to 13.56 MHz. When the electric bias is used together with the high frequency power HF, it is applied to the substrate support 14 to attract ions to the substrate W. In one example, the electric bias is applied to the lower electrode 18. When the electric bias is applied to the lower electrode 18, the potential of the substrate W placed on the substrate support 14 fluctuates within a period defined by the second frequency. The electric bias may be applied to a bias electrode provided in the electrostatic chuck 20.

[0044] When plasma processing is performed in the substrate processing apparatus 1, a processing gas is supplied from a gas supply source (gas source group 40, gas supply pipe 38, etc.) to the internal space 10s via a gas supply unit of the upper electrode 30. In addition, a high-frequency electric field is generated between the upper electrode 30 and the lower electrode 18 by supplying high-frequency power HF and / or an electric bias. The generated high-frequency electric field generates plasma from the processing gas in the internal space 10s.

[0045] The substrate processing apparatus 1 may include a power supply 70. The power supply 70 is connected to the top plate 34 of the upper electrode 30 and the chamber body 12. The power supply 70 is configured to supply a negative DC voltage or low-frequency power to at least one of the upper electrode 30 and the chamber body 12 during plasma processing. Positive ions in the plasma are attracted to and collide with the upper electrode 30 and / or the chamber body 12, which are at a negative potential. The DC voltage or low-frequency power may be supplied as a pulse wave or a continuous wave. In one example, the DC power supply 70 may be connected to only one of the top plate 34 of the upper electrode 30 and the chamber body 12, and configured to supply a negative DC voltage to only that one.

[0046] The substrate processing apparatus 1 may further include a control unit 80. The control unit 80 may be a computer including a processor, a storage unit such as a memory, an input device, a display device, a signal input / output interface, and the like. The control unit 80 controls each unit of the substrate processing apparatus 1. In the control unit 80, an operator can use the input device to input commands and the like to manage the substrate processing apparatus 1. In addition, the control unit 80 can visualize and display the operating status of the substrate processing apparatus 1 using the display device. Furthermore, the storage unit stores a control program and recipe data. The control program is executed by the processor to execute various processes in the substrate processing apparatus 1. The processor executes the control program and controls each unit of the substrate processing apparatus 1 according to the recipe data. In one exemplary embodiment, a part or all of the control unit 80 may be provided as a part of the configuration of an external device of the substrate processing apparatus 1.

[0047] <Configuration of Plasma Exposed Part in Chamber 10> In one example, the portion of the chamber 10 that is exposed to the plasma generated in the interior space 10s is constructed of a conductive silicon-containing material.

[0048] Fig. 2 is a diagram for explaining an example of a cross-sectional structure of the chamber body 12. As shown in Fig. 2, the chamber body 12 includes a first layer 122 and a second layer 124 from the outside to the inside (the side facing the internal space 10s).

[0049] The first layer 122 constitutes the outer wall of the chamber body 12. The first layer 122 is made of, for example, aluminum. The second layer 124 constitutes the inner wall of the chamber body 12. The second layer 124 is a portion exposed to plasma generated in the internal space 10s. The second layer 124 is made of a silicon-containing material having electrical conductivity. The silicon-containing material may be, for example, silicon (single crystal silicon, polycrystalline silicon) or silicon carbide. The thickness of the second layer 124 may be, for example, 5 mm to 50 mm. The surface of the silicon-containing material constituting the second layer may be coated with carbon.

[0050] The second layer 124 may be removably attached to the first layer 122. For example, the second layer 124 may be configured as a liner shaped to cover the inner circumferential surface of the first layer 122, and the liner may be removably attached to the first layer 122. In one example, the second layer 124 may be integrally formed with the first layer 122. For example, the second layer 124 may be integrally formed by coating the inner circumferential surface of the first layer 122 with a silicon-containing material.

[0051] The chamber body 12 may have three or more layers, for example, may further have one or more layers between the first layer 122 and the second layer 124, which are made of a material different from the first layer 122 and the second layer 122. The chamber body 12 may be a single layer, and the entire chamber body 12 may be made of a silicon-containing material having electrical conductivity. The surface of the inside of the chamber body 12 (the side facing the internal space 10s) may be coated with carbon.

[0052] The lower surface of the top plate 34 of the upper electrode 30 faces the internal space 10s and is exposed to plasma, like the second layer of the chamber body 12. The top plate 34 is made of a conductive silicon-containing material. The top plate 34 may be made of, for example, silicon (single crystal silicon) or silicon carbide. The material constituting the top plate 34 and the second layer of the chamber body 12 may be the same material or different materials. The lower surface of the top plate 34 may be coated with, for example, carbon.

[0053] In one example, only a portion of the plasma-exposed portion of the chamber body 12 and the upper electrode 30 may be made of a conductive silicon-containing material. For example, the top plate 34 of the upper electrode 30 may be made of a conductive silicon-containing material, and the chamber body 12 may be made of aluminum having a corrosion-resistant film such as yttrium oxide formed on its surface. In addition, for example, a portion or the entire inner wall of the chamber body 12 may be made of a second layer 124 made of a conductive silicon-containing material, and the top plate 34 of the upper electrode 30 may be made of an insulating material such as quartz.

[0054] Furthermore, among other members within the chamber body 12, those that may be exposed to the plasma generated in the internal space 10s, such as the shield 46 and the baffle plate 48, may be made of a conductive silicon material.

[0055] <An example of the substrate W> 3 is a diagram showing an example of a cross-sectional structure of a substrate W. The substrate W is an example of a substrate to which the present processing method can be applied. The substrate W has a silicon-containing film SF. The substrate W may have a base film UF and a mask film MK. As shown in FIG. 3, the substrate W may be formed by stacking the base film UF, the silicon-containing film SF, and the mask film MK in this order.

[0056] The undercoat film UF may be, for example, a silicon wafer, an organic film formed on a silicon wafer, a dielectric film, a metal film, a semiconductor film, etc. The undercoat film UF may be configured by laminating a plurality of films.

[0057] The silicon-containing film SF may be a silicon oxide film, a silicon nitride film, a silicon oxynitride film (SiON film), or a Si-ARC film. The silicon-containing film SF may include a polycrystalline silicon film. The silicon-containing film SF may be configured by stacking a plurality of films. The silicon oxide film may be a stacked film including at least two selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polycrystalline silicon film. For example, the silicon-containing film SF may be configured by alternately stacking a silicon oxide film and a polycrystalline silicon film. Also, for example, the silicon-containing film SF may be configured by alternately stacking a silicon oxide film and a silicon nitride film.

[0058] The undercoat film UF and / or the silicon-containing film SF may be formed by a CVD method, a spin coating method, etc. The undercoat film UF and / or the silicon-containing film SF may be a flat film or may be a film having irregularities.

[0059] The mask film MK is formed on the silicon-containing film SF. The mask film MK defines at least one opening OP on the silicon-containing film SF. The opening OP is a space on the silicon-containing film SF and is surrounded by a sidewall S1 of the mask film MK. That is, in FIG. 3, the silicon-containing film SF has a region covered by the mask film MK and a region exposed at the bottom of the opening OP.

[0060] The openings OP may have any shape in a plan view of the substrate W (when the substrate W is viewed from top to bottom in FIG. 3). The shape may be, for example, a hole shape, a line shape, or a combination of a hole shape and a line shape. The mask film MK may have a plurality of side walls S1, which define a plurality of openings OP. The plurality of openings OP may each have a line shape and be arranged at regular intervals to form a line and space pattern. Also, the plurality of openings OP may each have a hole shape and form an array pattern.

[0061] The mask film MK is, for example, an organic film or a metal-containing film. The organic film may be, for example, a spin-on carbon film (SOC), an amorphous carbon film, or a photoresist film. The metal-containing film may contain, for example, tungsten, tungsten carbide, or titanium nitride. The mask film MK may be formed by a CVD method, a spin coating method, or the like. The opening OP may be formed by etching the mask film MK. The mask film MK may be formed by lithography.

[0062] <An example of this processing method> 4 is a flowchart showing an example of a substrate processing method (hereinafter referred to as "this processing method") in the substrate processing apparatus 1. This processing method is an example of supplying a processing gas into a chamber in which the substrate W is placed to generate plasma in order to etch a dielectric film DF of the substrate W. This processing method includes a step of preparing a substrate (step ST1), a step of supplying a processing gas (step ST2), and a step of generating plasma (step ST3). Note that steps ST2 and ST3 may be performed in parallel.

[0063] In the following example, a case will be described in which the present processing method shown in Fig. 4 is performed on a substrate W shown in Fig. 3. In the following example, a control unit 80 shown in Fig. 1 controls each unit of the substrate processing apparatus 1 to perform the present processing method.

[0064] (Step ST1: Preparation of the substrate) In step ST1, the substrate W is prepared in the internal space 10s of the chamber 10. In the internal space 10s, the substrate W is placed on an upper surface of a substrate support 14 and held by an electrostatic chuck 20. At least a part of the process for forming each component of the substrate W may be performed in the internal space 10s. Also, after all or a part of each component of the substrate W is formed in an apparatus or chamber outside the substrate processing apparatus 1, the substrate W may be carried into the internal space 10s and placed on an upper surface of the substrate support 14.

[0065] (Step ST2: Supply of processing gas) In step ST2, a processing gas is supplied from a gas supply unit into the internal space 10s. The processing gas is a gas used for etching the silicon-containing film SF formed on the substrate W.

[0066] The process gas is hydrogen fluoride (HF) gas and C x H y F z gas (where x and z are integers of 1 or more, and y is an integer of 0 or more; hereafter referred to as "CF·CHF-based gas").

[0067] The HF gas may have the largest flow rate in the total flow rate of the reactive gas in the processing gas. The flow rate of the HF gas may be, for example, 50 vol.% or more, 60 vol.% or more, 70 vol.% or more, 80 vol.% or more, 90 vol.% or more, or 95 vol.% or more with respect to the total flow rate of the reactive gas. The flow rate of the HF gas may be, for example, less than 100 vol.%, 99.5 vol.% or less, 98 vol.% or less, or 96 vol.% or less with respect to the total flow rate of the reactive gas. In one example, the flow rate of the hydrogen fluoride gas is adjusted to 70 vol.% or more and 96 vol.% or less with respect to the total flow rate of the reactive gas. In this embodiment, the reactive gas does not include an inert gas such as a noble gas.

[0068] In addition, a fluorine-containing gas capable of generating hydrogen fluoride (HF) species in the chamber during plasma processing may be used in place of a part or all of the HF gas. The HF species includes at least one of hydrogen fluoride gas, radicals, and ions. In one example, the fluorine-containing gas may be a hydrofluorocarbon gas. The fluorine-containing gas may also be a mixed gas containing a hydrogen source and a fluorine source. The hydrogen source may be, for example, H 2 , N.H. 3 , H 2 O, H 2 O 2 or hydrocarbons (CH 4 , C 3 H 6 The fluorine source may be NF3, SF6, WF 6 , XeF 2 , a fluorocarbon or a hydrofluorocarbon.

[0069] CF·CHF-based gases include, for example, CF 4 Gas, C. 3 F 8 Gas, C. 4 F 6 Gas, C. 4 F 8 Gas, CH 2 F 2 Gas, CHF 3 Gas, CH 3 F gas, C 2 HF 5 Gas, C. 2 H 2 F 4 Gas, C. 2 H 3 F 3 Gas, C. 2 H 4 F 2 Gas, C. 3 HF 7 Gas, C. 3 H 2 F 2 Gas, C. 3 H 2 F 4 Gas, C. 3 H 2 F 6 Gas, C. 3 H 3 F 5 Gas, C. 4 H 2 F 6 Gas, C. 4 H 5 F 5 Gas, C. 4 H 2 F 8 Gas, C. 5 H 2 F 6 Gas, C. 5 H 2 F 10 Gas and C 5 H 3 F 7 In one example, the CF.CHF-based gas may be at least one selected from the group consisting of C 4 H 2 F 6 Gas, C. 4 H 2 F8 Gas, C. 3 H 2 F 4 Gas and C 3 H 2 F 6 The gas is at least one selected from the group consisting of gases.

[0070] The flow rate of the CF·CHF-based gas may be, for example, 1 vol% or more, or 5 vol% or more, relative to the total flow rate of the reactive gases in the process gas. The flow rate of the CF·CHF-based gas may be smaller than the flow rate of the HF gas, for example, 20 vol% or less, 15 vol% or less, or 10 vol% or less, relative to the total flow rate of the reactive gases.

[0071] The processing gas used in this processing method may be appropriately selected based on the material of the silicon-containing film SF, the material of the mask film MK, the material of the undercoat film UF, the pattern of the mask film MK, the etching depth, the aspect ratio, etc. For example, the processing gas may further contain at least one selected from the group consisting of a phosphorus-containing gas, a halogen-containing gas, a nitrogen-containing gas, and an oxygen-containing gas as a reactive gas.

[0072] The phosphorus-containing gas protects the sidewall of the silicon-containing film SF during etching of the silicon-containing film SF. 3 Gas, PF 5 Gas, POF 3 Gas, HPF 6 Gas, PCl 3 Gas, PCl 5 Gas, POCl 3 Gas, PBr 3 Gas, PBr 5 Gas, POBr 3 Gas, P.I. 3 Gas, P 4 O 10 Gas, P 4 O 8 Gas, P 4 O 6 Gas, pH 3 Gas, Ca 3 P 2 Gas, H 3 PO 4 Gas and Na 3PO 4 Among these gases, at least one selected from the group consisting of PF 3 Gas, PF 5 Gas, PCl 3 Phosphorus-containing halogen gases such as PF 3 Gas, PF 5 A phosphorus fluoride-containing gas such as a gas may be used.

[0073] The halogen-containing gas can adjust the shape of the mask film MK and the silicon-containing film SF during etching of the silicon-containing film SF. The halogen-containing gas may be a gas containing a halogen element other than fluorine. The halogen-containing gas may be a chlorine-containing gas, a bromine-containing gas, and / or an iodine-containing gas. The chlorine-containing gas may be, for example, Cl 2 Gas, SiCl 2 Gas, SiCl 4 Gas, CCl 4 Gas, BCl 3 Gas, PCl 3 Gas, PCl 5 Gas, POCl 3 Bromine-containing gases include HBr gas, CBr 2 F 2 Gas, C. 2 F 5 Br gas, PBr 3 Gas, PBr 5 Gas, POBr 3 Gases such as HI gas and CF gas are suitable for iodine-containing gases. 3 I Gas, C 2 F 5 I Gas, C 3 F 7 I gas, IF 5 Gas, IF 7 Gas, I 2 Gas, P.I. 3 In one example, the halogen-containing gas is Cl 2 gas and / or HBr gas are used.

[0074] The nitrogen-containing gas can suppress the closure of the opening OP of the mask film MK during etching. The nitrogen-containing gas is, for example, NF 3 Gas, N2 Gas and NH 3 The gas may be at least one gas selected from the group consisting of gases.

[0075] The oxygen-containing gas, like the nitrogen-containing gas, can suppress the closure of the opening OP of the mask film MK during etching. The oxygen-containing gas is, for example, O 2 , CO, CO 2 , H 2 O and H 2 O 2 In one example, the oxygen-containing gas may be at least one gas selected from the group consisting of H 2 Gases other than O, e.g., O 2 , CO, CO 2 and H 2 O 2 The oxygen-containing gas is at least one gas selected from the group consisting of: The oxygen-containing gas causes less damage to the mask film MK and can suppress deterioration of the morphology.

[0076] 5 is a diagram showing an example of the shape of the mask film MK after etching. FIG. 5 shows an example of the shape (plan view) of the mask film MK when a sample substrate having the same structure as the substrate W is etched in the substrate processing apparatus 1. In FIG. 5, "No." indicates the sample number of the etched sample substrate. "Processing gas" indicates the processing gas used in etching, "A" indicates HF gas, C 4 H 2 F 6 Gas, O 2 Gas, NF 3 Gas, HBr gas and Cl 2 The process gas A contains HF gas at 80% by volume or more relative to the total flow rate of the reaction gas, and O 2 The gas contained in the process gas is 4 to 5% by volume relative to the total flow rate of the reaction gas. 3 Gas is not included, so O 2 This refers to a process gas (hereinafter referred to as "process gas B") that is the same as process gas A, except that the flow rate of the gas is increased. Process gas B is O 2The gas contains 6 to 7 volume % of the reaction gas with respect to the total flow rate of the reaction gas. "With" in "Upper electrode application" indicates that a negative DC voltage was supplied to the upper electrode 30 of the substrate processing apparatus 1 during etching, and "Without" indicates that a negative DC voltage was not supplied to the upper electrode 30. From the "Mask shape" in FIG. 5, it can be seen that the NF 3 It can be seen that when the processing gas A containing NF was used (samples 1 and 3), the circularity of the opening OP was deteriorated and steps were generated on the surface of the mask film MK. 3 Gas-free, O 2 When processing gas B with an increased gas flow rate was used (samples 2 and 4), the circularity of the opening OP was high and no steps were formed on the surface of the mask film MK, indicating that the morphology of the mask film MK was improved compared to when processing gas A was used (samples 1 and 3).

[0077] The process gas may include, for example, an inert gas (such as a noble gas, such as Ar) in addition to the reactive gases mentioned above.

[0078] The pressure of the process gas supplied into the internal space 10s is adjusted by controlling a pressure regulating valve of an exhaust device 50 connected to the chamber body 12. The pressure of the process gas may be, for example, 5 mTorr (0.7 Pa) to 100 mTorr (13.3 Pa), 10 mTorr (1.3 Pa) to 60 mTorr (8.0 Pa), or 20 mTorr (2.7 Pa) to 40 mTorr (5.3 Pa).

[0079] (Step ST3: Plasma generation) 6 is a diagram showing an example of a cross-sectional structure of the substrate W in step ST3. In step ST3, when high-frequency power and / or an electric bias is supplied from the plasma generating unit (high-frequency power supply 62 and / or bias power supply 64), a high-frequency electric field is generated between the upper electrode 30 and the substrate support 14. As a result, plasma is generated from the processing gas supplied into the internal space 10s.

[0080] The plasma generated from the HF gas and the CF·CHF-based gas contains HF species. In step ST3, the HF species in the plasma are attracted to the substrate W, react with silicon in the silicon-containing film SF, and volatilize as a silicon fluoride compound. That is, the HF species functions as an etchant for the silicon-containing film SF. At this time, the carbon contained in the CF·CHF-based gas deposits carbon on the surface of the mask film MK, and can protect the surface. In this way, as shown in FIG. 6, a recess RC (e.g., a hole or trench-shaped recess) is formed that is defined by the sidewall S2 of the silicon-containing film SF, continuing from the opening OP formed in the mask film MK based on the shape of the opening OP of the mask film MK. The aspect ratio of the recess RC may be 20 or more, 30 or more, 40 or more, 50 or more, or 100 or more.

[0081] In step ST3, the temperature of the substrate support 14 may be controlled to a low temperature. The adsorption coefficient of HF radicals increases at low temperatures. Therefore, by controlling the temperature of the substrate support 14 to a low temperature to suppress an increase in the temperature of the substrate W, the adsorption of HF species (etchant) at the bottom BT of the recess RC is promoted. This can improve the etching rate of the silicon-containing film SF. The temperature of the substrate support 14 may be, for example, 0° C. or lower, −10° C. or lower, −20° C. or lower, −30° C. or lower, −40° C. or lower, or −70° C. or lower. The temperature of the substrate support 14 can be adjusted by a heat exchange medium supplied from a chiller unit.

[0082] In this embodiment, among the members constituting the chamber 10 of the substrate processing apparatus 1, the portion exposed to the plasma generated in the internal space 10s (hereinafter referred to as the "plasma-exposed portion") is made of a conductive silicon-containing material. The members constituting the chamber 10 include, for example, the chamber body 12 and the upper electrode 30. The silicon contained in the plasma-exposed portion may react with the HF species in the plasma in step ST3 and volatilize as a silicon fluoride compound from the surface of the plasma-exposed portion. That is, the surface of the plasma-exposed portion may be etched. However, in step ST3, the carbon contained in the CF·CHF-based gas is deposited on the plasma-exposed portion made of the conductive silicon-containing material to protect the exposed portion. This makes it possible to prevent the surface of the plasma-exposed portion from being excessively etched and scraped (damaged). According to experiments by the present inventors, when the plasma-exposed portion is made of quartz instead of a conductive silicon-containing material, no improvement in the degree of damage to the plasma-exposed portion (quartz) was observed even when the CF·CHF-based gas was added to the processing gas made of HF gas (1% by volume relative to the total flow rate of the reaction gas). This is thought to be because the carbon contained in the CF·CHF gas reacted with the oxygen in the quartz to produce CO, which was consumed, resulting in an insufficient protection effect for the plasma-exposed parts.

[0083] In addition, in this embodiment, even if the plasma exposed portion is etched, what is generated is a highly volatile silicon fluoride compound as described above. Therefore, the silicon fluoride compound can be easily removed from the internal space 10s after the plasma treatment, and an increase in particles in the internal space 10s can be suppressed.

[0084] In step ST3, the power supply 70 may supply a negative DC voltage to the upper electrode 30 and the chamber body 12. As a result, positive ions in the plasma are attracted to the upper electrode 30 and / or the chamber body 12, which are at a negative potential, and collide with them. As a result, silicon and secondary electrons are emitted from the plasma-exposed portion. Since the surface of the plasma-exposed portion is more scraped, it is possible to suppress excessive deposition of carbon on the plasma-exposed portion, for example, when the flow rate of the CF.CHF-based gas is high. In one example, a negative DC voltage may be supplied only to the upper electrode 30, and the potential of the chamber body 12 may be kept at 0. Alternatively, a negative DC voltage may be supplied only to the chamber body 12. In one example, the power supply 70 may supply low-frequency power to the upper electrode 30 and / or the chamber body 12 instead of a DC voltage. Note that, if oxygen is contained in the plasma, the emitted silicon combines with the oxygen to deposit on the mask MK as a silicon oxide compound, which can function as a protective film.

[0085] The emitted secondary electrons contribute to improving the plasma density. Moreover, the secondary electrons can modify the mask film MK and improve the etching resistance of the mask film MK. Furthermore, the charge state of the substrate W can be neutralized by the irradiation of the secondary electrons, and the linearity of the ions into the recesses RC formed by etching can be increased. As a result, effects such as improvement of the etching selectivity of the silicon-containing film SF relative to the mask film MK, suppression of shape abnormalities in the recesses RC formed by etching, and improvement of the etching rate can be obtained.

[0086] <Example> Using the substrate processing apparatus 1, this processing method was performed on a blanket substrate W having a photoresist film without openings, and the composition of the plasma in the internal space 10s 10 minutes after plasma generation was measured using a quadrupole mass analyzer.

[0087] In the first embodiment, the substrate processing apparatus 1 had a top plate 34 made of single crystal silicon and a chamber body 12 made of yttrium-coated aluminum. The processing gas was HF gas and C 4 H2 F 6 The gases were contained in a flow rate ratio (volume ratio) of 100: 1. The temperature of the substrate support 14 during plasma generation was set to -40°C.

[0088] In Example 2, the process gas was HF gas and C 4 H 2 F 6 The procedure is the same as in Example 1, except that the flow rate ratio of the gas is 100:5.

[0089] Reference Example 1 is the same as Example 1, except that the processing gas was HF gas alone.

[0090] The results of the measurements using the quadrupole mass spectrometer according to Example 1, Example 2, and Reference Example 1 are shown in Table 1. As shown in Table 1, Examples 1 and 2 have a higher SiF 3 The amount of SiF decreased while the amount of HF increased. 3 is a reaction product generated when silicon on the top plate 34 reacts with HF species in the plasma, so SiF 3 The decrease in the amount of HF species indicates that the reaction between silicon and HF species was suppressed on the top plate 34. That is, it is considered that the reaction between silicon and HF species was suppressed on the top plate 34 in Examples 1 and 2 compared to Reference Example 1, and therefore etching (shaving) of the surface of the top plate 34 was suppressed. Also, as a result of the suppression of consumption of HF species on the top plate 34, it is considered that the amount of HF species supplied to the substrate W was increased in Examples 1 and 2 compared to Reference Example 1. The reason for this is that the use of C as a processing gas is 4 H 2 F 6 This is believed to be because, in Examples 1 and 2 containing gas, unlike Reference Example 1 which does not contain CH.CHF-based gas, carbon was deposited on the top plate 34, protecting the surface of the top plate 34. 4 H 2 F 6 In Example 2, in which the gas flow rate was increased, the amount of SiF in the plasma was smaller than in Example 1. 3This is believed to be because the amount of carbon deposited on the top plate 34 in Example 2 was greater than that in Example 1, and the surface protection effect of the top plate 34 was greater than that in Example 1.

[0091] [Table 1]

[0092] The above embodiments have been described for purposes of illustration and various modifications may be made without departing from the scope and spirit of the disclosure.

[0093] For example, in this processing method, before step ST1, a precoat may be formed on the plasma-exposed portion in chamber 10. By forming a precoat before starting plasma processing, it is possible to prevent the surface of the plasma-exposed portion from being excessively scraped (damaged).

[0094] The precoat may be a film containing carbon. In one example, the precoat can be formed by generating plasma from the above-mentioned CF·CHF-based gas. The precoat can be formed by, for example, Chemical Vapor Deposition (CVD) or Atomic Layer Deposition (ALD).

[0095] Pre-coating may be performed after each processing of a substrate W, or after processing a predetermined number or a predetermined lot of substrates W, or after processing substrates for a predetermined period of time.

[0096] Further, for example, a substrate processing apparatus using any plasma source such as inductively coupled plasma or microwave plasma other than the capacitively coupled substrate processing apparatus 1 may be used, and at least a part of the portion exposed to the plasma in the chamber of the substrate processing apparatus may be made of a conductive silicon-containing material. The substrate processing apparatus may include a gas supply unit on the side wall of the chamber. [Explanation of symbols]

[0097] 1: substrate processing apparatus, 10: chamber, 10s: internal space, 12: chamber body, 122: first layer, 124: second layer, 14: substrate support, 16: electrode plate, 18: lower electrode, 20: electrostatic chuck, 30: upper electrode, 34: top plate, 50: exhaust device, 62: high frequency power source, 64: bias power source, 70: power source, 80: control unit, CT: control unit, SF: silicon-containing film, MK: mask film, OP: opening, PF: protective film, RC: recess, UF: base film, W: substrate

Claims

1. A chamber; a substrate support disposed within the chamber; A gas mixture of HF gas and C x H y F z A gas supply unit connected to a supply source of a reaction gas containing a gas (x and z are integers of 1 or more, and y is an integer of 0 or more); a plasma generating unit configured to generate plasma from the reactive gas supplied into the chamber from the gas supply unit; a control unit configured to control the gas supply unit to supply the reactive gas into the chamber so that a flow rate ratio of the HF gas to a total flow rate of the reactive gas is maximized in order to etch a silicon-containing film on a substrate supported by the substrate support, and to control the plasma generation unit to generate plasma from the reactive gas in the chamber; Equipped with At least a portion of the chamber exposed to the plasma is made of a conductive silicon-containing material.

2. The C supplied into the chamber x H y F z The substrate processing apparatus according to claim 1 , wherein a flow rate of the gas is 5% by volume or more with respect to a total flow rate of the reaction gas.

3. 3. The substrate processing apparatus according to claim 1, wherein an inner wall of the chamber is provided with a liner made of a conductive silicon-containing material.

4. An upper electrode is disposed opposite the substrate support, The substrate processing apparatus according to claim 1 , wherein the upper electrode has the gas supply unit.

5. 5. The substrate processing apparatus according to claim 4, wherein the upper electrode comprises a top plate having a plurality of gas ejection holes for supplying the reactive gas into the chamber, the top plate being made of a conductive silicon material.

6. 6. The substrate processing apparatus according to claim 1, further comprising a power supply for supplying a negative DC voltage or a low frequency RF power to the chamber.

7. 6. The substrate processing apparatus according to claim 4, further comprising a power supply for supplying a negative DC voltage or a low-frequency RF power to the upper electrode.

8. The substrate processing apparatus according to claim 1 , wherein a side wall constituting the chamber has the gas supply unit.

9. providing a substrate having a silicon-containing film on a substrate support in a chamber; HF gas and C x H y F z supplying a reaction gas containing a gas (x and z are integers of 1 or more, and y is an integer of 0 or more) into the chamber, the reaction gas having a flow rate ratio of the HF gas being the highest with respect to a total flow rate of the reaction gas; generating a plasma from the reactive gas supplied into the chamber to etch the silicon-containing film; A method for processing a substrate, wherein at least a portion of the chamber exposed to the plasma is made of a conductive silicon-containing material.

10. Said C x H y F z 10. The substrate processing method according to claim 9, wherein a flow rate of the gas is 5 volume % or more with respect to a total flow rate of the reaction gas.

11. 11. The substrate processing method according to claim 9, wherein an inner wall of the chamber is provided with a liner made of the conductive silicon-containing material.

12. 12. The substrate processing method according to claim 9, wherein in the step of generating the plasma, a negative DC voltage or a low-frequency RF power is supplied to the chamber.

13. 13. The substrate processing method according to claim 9, wherein a sidewall constituting the chamber is provided with a gas supply portion that supplies the reaction gas into the chamber.

14. 13. The substrate processing method according to claim 9, further comprising: an upper electrode disposed opposite the substrate support, the upper electrode comprising a gas supply unit that supplies the reactive gas into the chamber.

15. 15. The substrate processing method according to claim 14, wherein the upper electrode comprises a top plate having a plurality of gas ejection holes for supplying the reactive gas into the chamber, the top plate being made of a conductive silicon material.

16. 16. The substrate processing method according to claim 14, wherein in the step of generating the plasma, a negative DC voltage or a low-frequency RF power is supplied to the upper electrode.

17. Said C x H y F z Gas is C 4 H 2 F 6 Gas, C. 4 H 2 F 8 Gas, C. 3 H 2 F 4 Gas and C 3 H 2 F 6 17. The substrate processing method according to claim 9, wherein the gas is at least one selected from the group consisting of gases.

18. 18. The substrate processing method according to claim 9, wherein the reactive gas further contains at least one gas selected from the group consisting of a halogen-containing gas, an oxygen-containing gas, and a nitrogen-containing gas.

19. The substrate processing apparatus of claim 1, wherein the reactive gas further comprises a phosphorus-containing gas.

20. The substrate processing method of claim 9, wherein the reactive gas further comprises a phosphorus-containing gas.

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