Substrate processing method and substrate processing apparatus

Abstract

Provides are a substrate processing method for etching a film, and a substrate processing apparatus.　This substrate processing method comprises: (a) a step for preparing a film that contains silicon (Si) and / or boron (B), carbon (C) and nitrogen (N) on a substrate; (b) a step for supplying a gas that contains fluorine (F) to the substrate to fluorinate the film; and (c) a step for supplying plasma of a gas that contains hydrogen (H) and / or nitrogen (N) to the substrate to etch the fluorinated film.

Description

Substrate processing method and substrate processing apparatus

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

[0002] Patent Document 1 discloses a method for selectively etching a silicon nitride film, which includes a first step of placing a substrate to be processed having the silicon nitride film in a processing space, a second step of introducing a gas containing H and F into the processing space, and a third step of selectively introducing radicals of an inert gas into the processing space.

[0003] Japanese Patent Application Laid-Open No. 2019-12759

[0004] In one aspect, the present disclosure provides a substrate processing method and a substrate processing apparatus for etching a film.

[0005] In order to solve the above-mentioned problems, according to one aspect, there is provided a substrate processing method comprising the steps of: (a) preparing a film containing silicon (Si) and / or boron (B), carbon (C) and nitrogen (N) on a substrate; (b) supplying a gas containing fluorine (F) to the substrate to fluorinate the film; and (c) supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate to etch the fluorinated film.

[0006] According to one aspect, a substrate processing method and a substrate processing apparatus for etching a film can be provided.

[0007] 1 is a schematic diagram illustrating an example of the configuration of a plasma processing apparatus according to an embodiment; FIG. 2 is a flowchart illustrating an example of a film formation process according to an embodiment; FIG. 3 is a schematic cross-sectional view of a substrate; FIG. 4 is a schematic cross-sectional view of a substrate; FIG. 5 is a schematic cross-sectional view of a substrate; FIG. 6 is a schematic cross-sectional view of a substrate; FIG. 7 is a time chart for a deposition process of a SiCN film; FIG. 8 is a time chart for an etching process of a SiCN film; FIG. 9 is a time chart for a deposition process of a SiN film; FIG. 10 is a time chart for an etching process of a Si film; FIG. 11 is a schematic diagram illustrating a film etching process; FIG. 12 is a schematic diagram illustrating a film etching process; FIG. 13 is a graph illustrating the relationship between temperature and etching amount.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Substrate Processing Apparatus] A plasma processing apparatus (substrate processing apparatus) 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is an example of a schematic diagram showing an example of the configuration of the plasma processing apparatus 100 according to this embodiment.

[0010] The plasma processing apparatus 100 has a cylindrical processing vessel 1 with a ceiling and an open bottom end. The entire processing vessel 1 is made of, for example, quartz. A ceiling plate 2 made of quartz is provided near the upper end of the processing vessel 1, and the area below the ceiling plate 2 is sealed. A cylindrical metal manifold 3 is connected to the opening at the lower end of the processing vessel 1 via a sealing member 4 such as an O-ring.

[0011] The manifold 3 supports the lower end of the processing vessel 1, and a wafer boat 5 (substrate support portion) carrying a large number of semiconductor wafers (hereinafter referred to as "substrates W") (e.g., 25 to 150) stacked as substrates is inserted into the processing vessel 1 from below the manifold 3. In this manner, the processing vessel 1 accommodates the large number of substrates W generally horizontally, with spacing between them in the vertical direction. The wafer boat 5 is made of, for example, quartz. The wafer boat 5 has three rods 6 (two are shown in FIG. 1 ), and the large number of substrates W are supported by grooves (not shown) formed in the rods 6.

[0012] The wafer boat 5 is placed on a table 8 via a heat-retaining cylinder 7 made of quartz. The table 8 is supported on a rotating shaft 10 that passes through a metal (stainless steel) cover 9 that opens and closes the opening at the bottom end of the manifold 3.

[0013] A magnetic fluid seal 11 is provided at the penetration portion of the rotating shaft 10, hermetically sealing and rotatably supporting the rotating shaft 10. A seal member 12 is provided between the peripheral portion of the lid 9 and the lower end of the manifold 3 to maintain airtightness inside the processing vessel 1.

[0014] The rotation shaft 10 is attached to the tip of an arm 13 supported by a lifting mechanism (not shown), such as a boat elevator, and the wafer boat 5 and the lid 9 are raised and lowered as a unit to be inserted into and removed from the processing vessel 1. Note that the table 8 may be fixed to the lid 9 side so that the substrates W can be processed without rotating the wafer boat 5.

[0015] The plasma processing apparatus 100 also includes a gas supply unit 20 that supplies predetermined gases, such as a processing gas and a purge gas, into the processing chamber 1 .

[0016] The gas supply unit 20 has gas supply pipes 21 to 24. The gas supply pipes 21, 22, and 23 are made of, for example, quartz, penetrate the side wall of the manifold 3 inward, bend upward, and extend vertically. A plurality of gas holes 21g, 22g, and 23g are formed at predetermined intervals in the vertical portions of the gas supply pipes 21, 22, and 23 over a length in the vertical direction corresponding to the wafer support range of the wafer boat 5. Each of the gas holes 21g, 22g, and 23g discharges gas horizontally. The gas supply pipe 24 is made of, for example, quartz, and is a short quartz pipe that penetrates the side wall of the manifold 3.

[0017] The gas supply pipe 21 has a vertical portion (the vertical portion where the gas hole 21g is formed) disposed within the processing chamber 1. A first processing gas is supplied to the gas supply pipe 21 from a gas supply source 21a via a gas pipe. The gas pipe is provided with a flow rate controller 21b and an on-off valve 21c. Thus, the first processing gas from the gas supply source 21a is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 21.

[0018] A vertical portion of the gas supply pipe 22 (the vertical portion where the gas holes 22g are formed) is provided inside the processing chamber 1. A second processing gas is supplied to the gas supply pipe 22 from a gas supply source 22a via a gas pipe. A flow rate controller 22b and an on-off valve 22c are provided on the gas pipe. Thus, the second processing gas from the gas supply source 22a is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 22.

[0019] The gas supply pipe 23 has a vertical portion (the vertical portion where the gas holes 23g are formed) disposed in a plasma generation space, which will be described later. A third process gas is supplied to the gas supply pipe 23 from a gas supply source 23a via a gas pipe. The gas pipe is provided with a flow rate controller 23b and an on-off valve 23c. As a result, the third process gas from the gas supply source 23a is supplied to the plasma generation space via the gas pipe and the gas supply pipe 23, and is converted into plasma in the plasma generation space, and activated species (ions, radicals, etc.) of the third process gas are supplied into the processing vessel 1.

[0020] A purge gas is supplied to the gas supply pipe 24 from a purge gas supply source (not shown) via a gas pipe. A flow rate controller (not shown) and an on-off valve (not shown) are provided in the gas pipe (not shown). Thus, the purge gas from the purge gas supply source is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 24. The purge gas may be, for example, nitrogen (N ２ In the above description, the purge gas is supplied from the purge gas supply source into the processing chamber 1 through the gas piping and the gas supply pipe 24, but the present invention is not limited to this, and the purge gas may be supplied from any of the gas supply pipes 21 to 23.

[0021] 1 illustrates a gas supply pipe connected to one gas supply source, but this is not limited thereto. A gas supply pipe may be connected to multiple gas supply sources, and a flow rate controller and an on-off valve provided for each gas supply source may be used to switch between different process gases and supply them to the gas supply pipe. The number of gas supply pipes is not limited to that shown in FIG. 1.

[0022] A plasma generation mechanism 30 is formed on a part of the sidewall of the processing chamber 1. The plasma generation mechanism 30 generates activated species of the third processing gas by converting the third processing gas into plasma.

[0023] The plasma generation mechanism 30 includes a plasma partition wall 32, a pair of plasma electrodes 33 (one of which is shown in FIG. 1), a power supply line 34, a high-frequency power supply 35, and an insulating protective cover 36.

[0024] The plasma compartment wall 32 is airtightly welded to the outer wall of the processing vessel 1. The plasma compartment wall 32 is made of, for example, quartz. The plasma compartment wall 32 has a concave cross section and covers an opening 31 formed in the side wall of the processing vessel 1. The opening 31 is elongated in the vertical direction so as to cover all of the substrates W supported on the wafer boat 5 in the vertical direction. A gas supply pipe 23 for discharging a third processing gas is disposed in an inner space defined by the plasma compartment wall 32 and communicating with the inside of the processing vessel 1, i.e., a plasma generation space.

[0025] A pair of plasma electrodes 33 (one electrode is shown in FIG. 1 ) each have an elongated shape and are arranged facing each other in the vertical direction on the outer surfaces of both sides of the plasma compartment wall 32. Each plasma electrode 33 is held by, for example, a holder (not shown) provided on the side of the plasma compartment wall 32. A power supply line 34 is connected to the lower end of each plasma electrode 33.

[0026] The power supply line 34 electrically connects each plasma electrode 33 to the high-frequency power supply 35. In the illustrated example, one end of the power supply line 34 is connected to the lower end of each plasma electrode 33, and the other end is connected to the high-frequency power supply 35.

[0027] A high-frequency power supply 35 is connected to the lower end of each plasma electrode 33 via a power supply line 34, and supplies high-frequency power of, for example, 13.56 MHz to the pair of plasma electrodes 33. This applies the high-frequency power to the plasma generation space defined by the plasma partition wall 32. The third process gas discharged from the gas supply pipe 23 is converted into plasma in the plasma generation space to which the high-frequency power is applied, and the plasma of the third process gas thus generated is supplied into the processing vessel 1 through the opening 31.

[0028] The insulating protective cover 36 is attached to the outside of the plasma compartment wall 32 so as to cover the plasma compartment wall 32. A coolant passage (not shown) is provided inside the insulating protective cover 36, and cooled nitrogen (N ２The plasma electrode 33 is cooled by flowing a coolant such as a gas through the plasma electrode 33. A shield (not shown) may be provided between the plasma electrode 33 and the insulating protective cover 36 so as to cover the plasma electrode 33. The shield is made of a good conductor such as a metal and is grounded.

[0029] An exhaust port 40 for evacuating the processing vessel 1 is provided in a sidewall portion of the processing vessel 1 opposite the opening 31. The exhaust port 40 is elongated in the vertical direction to correspond to the wafer boat 5. An exhaust port cover member 41 having a U-shaped cross section is attached to the portion of the processing vessel 1 corresponding to the exhaust port 40. The exhaust port cover member 41 extends upward along the sidewall of the processing vessel 1. An exhaust pipe 42 for evacuating the processing vessel 1 through the exhaust port 40 is connected to the lower part of the exhaust port cover member 41. A pressure control valve 43 for controlling the pressure in the processing vessel 1 and an exhaust device 44 including a vacuum pump and the like are connected to the exhaust pipe 42. The processing vessel 1 is evacuated via the exhaust pipe 42 by the exhaust device 44.

[0030] A cylindrical heating mechanism 50 is provided to surround the outer periphery of the processing vessel 1 and heat the processing vessel 1 and the substrate W therein.

[0031] The plasma processing apparatus 100 also includes a control unit 60. The control unit 60 controls the operation of each unit of the plasma processing apparatus 100, for example, by opening and closing the on-off valves 21c to 23c to supply and stop the gases, by controlling the gas flow rates using the flow rate controllers 21b to 23b, and by controlling exhaust using the exhaust device 44. The control unit 60 also controls the on-off of high frequency power from the high frequency power source 35 and the temperature of the substrate W using the heating mechanism 50, for example.

[0032] The control unit 60 may be, for example, a computer. The computer programs that control the operations of each part of the plasma processing apparatus 100 are stored in a storage medium. The storage medium may be, for example, a flexible disk, a compact disk, a hard disk, a flash memory, a DVD, or the like.

[0033] Next, an example of a film formation process using the plasma processing apparatus 100 will be described.

[0034] 2 is a flowchart showing an example of a film forming process according to this embodiment.

[0035] As shown in FIG. 3A , the substrate W has a recess 211 such as a fine trench structure. Specifically, the substrate W has a first layer 200 and a second layer 210. The recess 211 is formed in the second layer 210. In the film formation process according to this embodiment, a film 220 (see FIGS. 3B and 3C ) is embedded in the recess 211. Here, the film 220 may be a film containing silicon (Si) and / or boron (B). Alternatively, the film 220 may be a film containing silicon (Si) and / or boron (B) and nitrogen (N). Alternatively, the film 220 may be a film containing silicon (Si) and / or boron (B), nitrogen (N), and carbon (C).

[0036] In step S101, the control unit 60 executes a deposition process for forming a film 220 on the substrate W.

[0037] In step S102, the control unit 60 executes an etching process to etch the substrate W. This removes the film 220 formed on the upper sidewalls of the recess 211, thereby preventing the upper opening of the recess 211 from being blocked by the film 220. Furthermore, as shown in FIG. 3B , the film 220 fills in the recess 211 from the bottom.

[0038] In step S103, the control unit 60 executes a deposition process to form a film 220 on the substrate W. The deposition process in step S103 may be the same as the deposition process in step S101.

[0039] In step S104, the control unit 60 determines whether the etching step S102 and the deposition step S103 have been repeated a predetermined number of times. If the etching step S102 and the deposition step S103 have not been repeated the predetermined number of times (S104: NO), the control unit 60 returns to step S102, and the etching step S102 and the deposition step S103 are repeated. If the etching step S102 and the deposition step S103 have been repeated the predetermined number of times (S104: YES), the control unit 60 ends the processing. As a result, the film 220 can be embedded in the recess 211 without any voids, as shown in FIG. 3C .

[0040] 2 may be configured to be performed within one plasma processing apparatus 100. Alternatively, the processes shown in FIG. 2 may be performed in a substrate processing system including a first plasma processing apparatus 100 that performs the deposition processes S101 and S103, a second plasma processing apparatus 100 that performs the etching process S102, and a vacuum transfer chamber (not shown) between the first plasma processing apparatus 100 and the second plasma processing apparatus 100.

[0041] 2 is described as being a batch-type plasma processing apparatus 100 that processes a plurality of substrates W. However, the present invention is not limited to this. The processing of this embodiment may also be applied to a single-wafer type plasma processing apparatus.

[0042] First Embodiment Next, the deposition step S101 (S103) and the etching step S102 in the case where the film 220 is a SiCN film will be described with reference to FIGS.

[0043] <Deposition of SiCN film> Fig. 4 is an example of a time chart of the SiCN film deposition step S101 (S103). In Fig. 4 (and Figs. 5 to 9 described later), essential components are indicated by solid lines, and additional components are indicated by dashed lines.

[0044] The SiCN film deposition step S101 uses an atomic layer deposition (ALD) method to form a SiCN film on the substrate W. Specifically, the deposition step S101 (S103) includes a step S301 of supplying a first precursor gas (Precursor 1) to the substrate W in the processing vessel 1, and a step S303 of supplying a first reactant gas (Reactant 1) to the substrate W in the processing vessel 1, and steps S301 and S303 are repeated a predetermined number of times.

[0045] In step S301, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply a first precursor gas from the gas supply pipe 21 into the processing chamber 1. As a result, the first precursor gas is adsorbed onto the surface of the substrate W. The first precursor gas (Precursor 1) is a gas containing silicon (Si) and carbon (C). Specifically, the first precursor gas may be an aminosilane-based gas such as BTBAS (Bis(t-butylamino)silane) or 3DMAS (Tris(dimethylamino)silane).

[0046] In step S303, the control unit 60 controls the on-off valve 22c and the flow rate controller 22b to supply a first reactant gas from the gas supply pipe 22 into the processing chamber 1. As a result, the first precursor gas adsorbed on the surface of the substrate W reacts with the first reactant gas to form a SiCN film. The first reactant gas (Reactant 1) is a gas containing nitrogen (N). Specifically, the first reactant gas is NH ３ The following gases can be used.

[0047] In the SiCN film deposition step S101, steps S301 and S303 are repeated a predetermined number of times to form a SiCN film on the substrate W with a desired thickness.

[0048] Furthermore, the SiCN film deposition step S101 may further include a step S302 of supplying a second precursor gas (Precursor 2) to the substrate W in the processing chamber 1 when a gas not containing carbon (C) is used as the first precursor gas in step S301. The second precursor gas (Precursor 2) is a gas containing carbon (C). Specifically, the second precursor gas is a C ２ H ４ , C ４ H ６A gas such as the above can be used. Note that step S302 may be performed after step S301 and before step S303. In the deposition step S101, steps S301 to S303 are repeated a predetermined number of times. In this case, examples of the first precursor gas include DCS (dichlorosilane) and HCDS (hexachlorodisilane). Note that even when a gas containing carbon (C) is used as the first precursor gas, step S302 of supplying a second precursor gas to the substrate W in the processing vessel 1 may be included.

[0049] In step S302, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply the second precursor gas from the gas supply pipe 21 into the processing chamber 1. The control unit 60 also controls the on-off valve 23c and the flow rate controller 23b to supply the second reactive gas (Reactant 2) (e.g., H ２ The control unit 60 also controls the high frequency power supply 35 to apply high frequency power (RF) to the plasma electrode 33. This makes it possible to adjust the carbon concentration (C) of the SiCN film.

[0050] The SiCN film deposition step S101 may further include a step S304 of supplying plasma of a hydrogen (H)-containing gas to the substrate W in the processing chamber 1. Note that step S304 may be performed after step S303. In the deposition step S101, steps S301 to S304 are repeated a predetermined number of times.

[0051] In step S304, the control unit 60 controls the on-off valve 23c and the flow rate controller 23b to supply a second reactive gas (Reactant 2) (e.g., H ２ The control unit 60 also controls the high frequency power supply 35 to apply high frequency power (RF) to the plasma electrode 33. This modifies the SiCN film with the plasma of the hydrogen-containing gas. This makes it possible to improve the film quality (e.g., film density) of the SiCN film.

[0052] <SiCN Film Etching> FIG. 5 is an example of a time chart of the SiCN film etching step S102.

[0053] The etching process S102 of the SiCN film includes a process S401 of supplying a gas containing fluorine (F) to the substrate W in the processing vessel 1, and a process S402 of supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate W in the processing vessel 1, and the processes S401 and S402 are repeated a predetermined number of times.

[0054] In step S401, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply a gas (Etchant 1) containing fluorine (F) from the gas supply pipe 21 into the processing chamber 1. As a result, the surface of the SiCN film is fluorinated to form a fluoride layer 221 (see FIGS. 10A to 10C described later). The gas (Etchant 1) containing fluorine (F) is HF gas, F ２ Gas, ClF ３ Gas, NF ３ Gas, CH ３ F gas, CHF ３ Gas, CF ４ Gas, C ４ F ６ Gases such as gases can be used.

[0055] In step S402, the control unit 60 controls the on-off valve 23c and the flow rate controller 23b to supply a gas (Reactant 1) containing hydrogen (H) and / or nitrogen (N) from the gas supply pipe 23 into the processing chamber 1. The control unit 60 also controls the high frequency power source 35 to apply high frequency power (RF) to the plasma electrode 33. This causes the fluorinated SiCN film to be etched with plasma of the gas containing hydrogen (H) and / or nitrogen (N). The gas containing hydrogen (H) and / or nitrogen (N) is NH ３ Gases containing hydrogen (H) and / or nitrogen (N) can be used (Reactant 1). ２ Gas such as H supplied from the gas supply pipe 23 may also be used (Reactant 2). ２ gas and N supplied from the gas supply pipe 24 ２ Gas and, by ２ and N ２ A plasma of the gas may be generated. ２ Gas and N２ A mixed gas of H ２ and N ２ A plasma of the gas may be generated.

[0056] The SiCN film etching step S102 may further include step S403 of supplying a heated gas to the substrate W in the processing chamber 1 to remove residues and the like from the surface of the substrate W. Step S403 may be performed after step S402. In the etching step S102, steps S401 to S403 are repeated a predetermined number of times.

[0057] As described above, the process of embedding a SiCN film includes: (a) preparing a film containing silicon (Si), carbon (C), and nitrogen (N) on the substrate W (deposition processes S101 and S103); (b) supplying a gas containing fluorine (F) to the substrate W to fluorinate the film (etching process S401); and (c) supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate W to etch the fluorinated film (etching process S402). Each of the processes (a), (b), and (c) is repeated multiple times in this order. That is, the order of processes (a), (b), and (c) constitutes one cycle, and this cycle is repeated multiple times. This allows the SiCN film to be etched in the etching process S102. The process of embedding the SiCN film includes step (a) and step (d) in which steps (b) and (c) are repeated multiple times. Each step may be repeated multiple times in the order of step (a) and step (d). That is, step (b) and step (c) may be performed in this order as a first cycle, and step (a) and step (d) may be performed in this order as a second cycle. After step (a), the first cycle (steps (b) and (c)) may be repeated multiple times (step (d)). Furthermore, this second cycle may be repeated multiple times.

[0058] 4 and 5, the film 220 is described as an SiCN film, but the present invention is not limited to this. The film 220 may be a film containing silicon (Si) and / or boron (B), nitrogen (N), and carbon (C) (SiCN film, SiBCN film, BCN film).

[0059] Second Embodiment Next, the deposition step S101 (S103) and the etching step S102 in the case where the film 220 is a SiN film will be described with reference to FIGS. 6 and 7. FIG.

[0060] <Deposition of SiN Film> FIG. 6 is an example of a time chart of the SiN film deposition step S101 (S103).

[0061] The SiN film deposition step S101 uses an atomic layer deposition (ALD) method to form a SiN film on the substrate W. Specifically, the deposition step S101 (S103) includes a step S311 of supplying a first precursor gas (Precursor 1) to the substrate W in the processing vessel 1, and a step S313 of supplying a first reactant gas (Reactant 1) to the substrate W in the processing vessel 1, and the steps S311 and S313 are repeated a predetermined number of times.

[0062] In step S311, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply a first precursor gas from the gas supply pipe 21 into the processing chamber 1. As a result, the first precursor gas is adsorbed onto the surface of the substrate W. The first precursor gas (Precursor 1) is a gas containing silicon (Si). Specifically, the first precursor gas may be a gas such as DCS (Dichlorosilane) or HCDS (Hexachlorodisilane).

[0063] In step S313, the control unit 60 controls the on-off valve 22c and the flow rate controller 22b to supply a first reactant gas from the gas supply pipe 22 into the processing chamber 1. As a result, the first precursor gas adsorbed on the surface of the substrate W reacts with the first reactant gas to form a SiN film. The first reactant gas (Reactant 1) is a gas containing nitrogen (N). Specifically, the first reactant gas is NH ３ The following gases can be used.

[0064] In the SiN film deposition step S101, steps S311 and S313 are repeated a predetermined number of times to form a SiN film on the substrate W with a desired thickness.

[0065] The SiN film deposition step S101 may further include steps S312 and S314 of supplying plasma of a hydrogen (H)-containing gas to the substrate W in the processing chamber 1. This step (S312) may be performed before step S313, or may be performed after step S313 (S314). In the deposition step S101, steps S311 to S314 are repeated a predetermined number of times.

[0066] In steps S312 and S314, the control unit 60 controls the on-off valve 23c and the flow rate controller 23b to supply a second reactive gas (Reactant 2) (e.g., H ２ The control unit 60 also controls the high frequency power supply 35 to apply high frequency power (RF) to the plasma electrode 33. This modifies the SiN film with the plasma of the hydrogen-containing gas. This makes it possible to improve the film quality (e.g., film density) of the SiN film.

[0067] <SiN Film Etching> FIG. 7 is an example of a time chart of the SiN film etching step S102.

[0068] The SiN film etching process S102 includes a process S411 of supplying a gas containing carbon (C) to the substrate W in the processing vessel 1, a process S412 of supplying a gas containing fluorine (F) to the substrate W in the processing vessel 1, and a process S413 of supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate W in the processing vessel 1, and the processes S411, S412, and S413 are repeated a predetermined number of times.

[0069] In step S411, the control unit 60 controls the on-off valve 22c and the flow rate controller 22b to supply a carbon (C)-containing gas (Etchant 2) into the processing chamber 1 through the gas supply pipe 22. This carbonizes the surface of the SiN film, forming a SiCN film on the surface of the SiN film. The carbon (C)-containing gas (Etchant 2) may be a gas containing carbon (C) and hydrogen (H) (CxHy), a gas containing carbon (C), hydrogen (H), and fluorine (F) (CxHyFz), or a gas containing carbon (C) and fluorine (F) (CxFy). When the gas containing carbon (C) and hydrogen (H) (CxHy) is used in step S411, the control unit 60 may control the high-frequency power source 35 to apply high-frequency power (RF) to the plasma electrode 33 to carbonize the surface of the SiN film using plasma of the carbon (C)-containing gas. In this case, a carbon (C)-containing gas (Etchant 2) may be supplied into the processing chamber 1 through the gas supply pipe 23 .

[0070] In step S412, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply a gas (Etchant 1) containing fluorine (F) from the gas supply pipe 21 into the processing chamber 1. As a result, at least a portion of the SiCN film formed on the surface of the SiN film is fluorinated to form a fluoride layer 221 (see FIGS. 10A to 10C described later). The gas (Etchant 1) containing fluorine (F) is HF gas, F ２ Gas, ClF ３ Gas, NF ３ Gas, CH ３ F gas, CHF ３ Gas, CF ４ Gas, C ４ F ６ It should be noted that if the surface of the SiN film is carbonized and fluorinated using a gas containing carbon (C) and fluorine (F) (CxHyFz or CxFy) in step S411, step S412 may be omitted.

[0071] In step S413, the control unit 60 controls the on-off valve 23c and the flow rate controller 23b to supply a gas (Reactant 1) containing hydrogen (H) and / or nitrogen (N) from the gas supply pipe 23 into the processing chamber 1. The control unit 60 also controls the high frequency power source 35 to apply high frequency power (RF) to the plasma electrode 33. This causes the fluorinated SiCN film to be etched with plasma of the gas containing hydrogen (H) and / or nitrogen (N). The gas containing hydrogen (H) and / or nitrogen (N) is NH ３ Gases containing hydrogen (H) and / or nitrogen (N) can be used (Reactant 1). ２ Gas such as H supplied from the gas supply pipe 23 may also be used (Reactant 2). ２ gas and N supplied from the gas supply pipe 24 ２ Gas and, by ２ and N ２ A plasma of the gas may be generated. ２ Gas and N ２ A mixed gas of H ２ and N ２ A plasma of the gas may be generated.

[0072] The SiN film etching step S102 may further include step S414 of supplying a heated gas to the substrate W in the processing chamber 1 to remove residues and the like from the surface of the substrate W. Step S414 may be performed after step S413. In the etching step S102, steps S411 to S414 are repeated a predetermined number of times.

[0073] As described above, the process of embedding a SiN film includes: (a) preparing a film containing silicon (Si), carbon (C), and nitrogen (N) on the substrate W (deposition processes S101 and S103 and step S411 of the etching process S102); (b) supplying a gas containing fluorine (F) to the substrate W to fluorinate the film (step S412 of the etching process S102); and (c) supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate W to etch the fluorinated film (step S413 of the etching process S102). Each of the steps (a), (b), and (c) is repeated multiple times in this order. That is, the order of steps (a), (b), and (c) constitutes one cycle, and this cycle is repeated multiple times. This allows the SiN film to be etched in the etching process S102. The process of embedding the SiN film includes step (a) and step (d) in which steps (b) and (c) are repeated multiple times, and each step may be repeated multiple times in the order of step (a) and step (d). That is, step (b) and step (c) may be performed in this order as a first cycle, and step (a) and step (d) may be performed in this order as a second cycle, and after step (a), the first cycle (steps (b) and (c)) may be repeated multiple times (step (d)). Furthermore, this second cycle may be repeated multiple times.

[0074] 6 and 7, the film 220 is described as an SiN film, but the present invention is not limited to this. The film 220 may be a film containing silicon (Si) and / or boron (B) and nitrogen (N) (e.g., a SiN film, a SiBN film, or a BN film).

[0075] Third Embodiment Next, the deposition step S101 (S103) and the etching step S102 in the case where the film 220 is a Si film will be described with reference to FIGS. 8 and 9. FIG.

[0076] <Si Film Deposition> FIG. 8 is an example of a time chart of the Si film deposition step S101 (S103).

[0077] The Si film deposition step S101 uses a CVD method to form a Si film on the substrate W. Specifically, the deposition step S101 (S103) includes a step S321 of supplying a first precursor gas (Precursor 1) to the substrate W in the processing chamber 1.

[0078] In step S321, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply a first precursor gas from the gas supply pipe 21 into the processing chamber 1. This forms a Si film on the substrate W. The first precursor gas (Precursor 1) is a gas containing silicon (Si). Specifically, the first precursor gas may be a gas such as MS (monosilane) or DS (disilane).

[0079] <Si Film Etching> FIG. 9 is an example of a time chart of the Si film etching step S102.

[0080] The Si film etching process S102 includes a process S421 of supplying a gas containing nitrogen (N) to the substrate W in the processing vessel 1, a process S422 of supplying a gas containing carbon (C) to the substrate W in the processing vessel 1, a process S423 of supplying a gas containing fluorine (F) to the substrate W in the processing vessel 1, and a process S424 of supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate W in the processing vessel 1, and the processes S421, S422, S423, and S424 are repeated a predetermined number of times.

[0081] In step S421, the control unit 60 controls the on-off valve 22c and the flow rate controller 22b to supply a nitrogen (N)-containing gas from the gas supply pipe 22 into the processing chamber 1. This causes the surface of the Si film to be nitrided, forming a SiN film on the surface of the Si film. The nitrogen (N)-containing gas is NH ３ The control unit 60 may also control the high frequency power supply 35 to apply high frequency power (RF) to the plasma electrode 33, and nitride the surface of the Si film using plasma of a nitrogen (N)-containing gas.

[0082] In addition, H supplied from the gas supply pipe 23 ２ gas and N supplied from the gas supply pipe 24 ２Gas and, by ２ and N ２ Alternatively, a gas plasma may be generated to nitride the surface of the Si film. Alternatively, a mixed gas of H gas and N gas may be supplied from the gas supply pipe 23 to generate plasma of H and N gas to nitride the surface of the Si film.

[0083] In step S422, the control unit 60 controls the on-off valve 22c and the flow rate controller 22b to supply a carbon (C)-containing gas (Etchant 2) into the processing chamber 1 through the gas supply pipe 22. This carbonizes the surface of the SiN film formed on the surface of the Si film, forming a SiCN film on the surface of the Si film. The carbon (C)-containing gas (Etchant 2) may be a gas containing carbon (C) and hydrogen (H) (CxHy), a gas containing carbon (C), hydrogen (H), and fluorine (F) (CxHyFz), or a gas containing carbon (C) and fluorine (F) (CxFy). When the gas containing carbon (C) and hydrogen (H) (CxHy) is used in step S422, the control unit 60 may control the high-frequency power source 35 to apply high-frequency power (RF) to the plasma electrode 33 to carbonize the surface of the SiN film using plasma of the carbon (C)-containing gas. In this case, a carbon (C)-containing gas (Etchant 2) may be supplied into the processing chamber 1 through the gas supply pipe 23 .

[0084] In step S423, the control unit 60 controls the on-off valve 21c and the flow rate controller 21b to supply a gas (Etchant 1) containing fluorine (F) from the gas supply pipe 21 into the processing chamber 1. As a result, the surface of the SiCN film formed on the surface of the Si film is fluorinated to form a fluoride layer 221 (see FIGS. 10A to 10C described later). The gas (Etchant 1) containing fluorine (F) is HF gas, F ２ Gas, ClF ３ Gas, NF ３ Gas, CH ３ F gas, CHF ３ Gas, CF ４ Gas, C ４ F ６It should be noted that if the surface of the SiN film is carbonized and fluorinated using a gas containing carbon (C) and fluorine (F) (CxHyFz or CxFy) in step S422, step S423 may be omitted.

[0085] In step S424, the control unit 60 controls the on-off valve 23c and the flow rate controller 23b to supply a gas (Reactant 1) containing hydrogen (H) and / or nitrogen (N) from the gas supply pipe 23 into the processing chamber 1. The control unit 60 also controls the high frequency power source 35 to apply high frequency power (RF) to the plasma electrode 33. This causes the fluorinated SiCN film to be etched with plasma of the gas containing hydrogen (H) and / or nitrogen (N). The gas containing hydrogen (H) and / or nitrogen (N) is NH ３ Gases containing hydrogen (H) and / or nitrogen (N) can be used (Reactant 1). ２ Gas such as H supplied from the gas supply pipe 23 may also be used (Reactant 2). ２ gas and N supplied from the gas supply pipe 24 ２ Gas and, by ２ and N ２ A plasma of the gas may be generated. ２ Gas and N ２ A mixed gas of H ２ and N ２ A plasma of the gas may be generated.

[0086] The Si film etching step S102 may further include step S425 of supplying a heated gas to the substrate W in the processing chamber 1 to remove residues and the like from the surface of the substrate W. Step S425 may be performed after step S424. In the etching step S102, steps S421 to S425 are repeated a predetermined number of times.

[0087] As described above, the process of embedding a Si film includes: (a) preparing a film containing silicon (Si), carbon (C), and nitrogen (N) on the substrate W (deposition processes S101 and S103 and processes S421 to S422 of the etching process S102); (b) supplying a gas containing fluorine (F) to the substrate W to fluorinate the film (process S423 of the etching process S102); and (c) supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate W to etch the fluorinated film (process S424 of the etching process S102). Each process is repeated multiple times in the order of processes (a), (b), and (c). That is, processes (a), (b), and (c) constitute one cycle, and this cycle is repeated multiple times. This allows the Si film to be etched in the etching process S102. The process of embedding the Si film includes step (a) and step (d) in which steps (b) and (c) are repeated multiple times. Each step may be repeated multiple times in the order of step (a) and step (d). That is, step (b) and step (c) may be performed in this order as a first cycle, and step (a) and step (d) may be performed in this order as a second cycle. After step (a), the first cycle (steps (b) and (c)) may be repeated multiple times (step (d)). Furthermore, this second cycle may be repeated multiple times.

[0088] In the explanation of FIGS. 8 and 9, the film 220 is an Si film, but the present invention is not limited to this. The film 220 may be a film containing silicon (Si) and / or boron (B) (Si film, SiB film, B film).

[0089] Next, etching of the SiCN film shown in Fig. 5 will be further described with reference to Figs. 10A to 10C. Figs. 10A to 10C are exemplary schematic diagrams illustrating the etching step S102 of the film 220. Note that the same applies to the case where a SiCN layer is formed by carbonizing a SiN film (see S411) and the case where a SiCN layer is formed by nitriding and carbonizing a Si film (see S421 and S422), and therefore redundant description will be omitted.

[0090] As shown in FIG. 10A, a film 220 containing silicon (Si), carbon (C) and nitrogen (N) is prepared on a substrate W.

[0091] As shown in FIG. 10B, in step S401, a gas containing fluorine (F) is supplied to the substrate W to fluorinate the surface of the film 220, thereby forming a fluoride layer 221.

[0092] As shown in FIG. 10C, in step S403, plasma of a gas containing hydrogen (H) and / or nitrogen (N) is supplied to the substrate W to etch the fluoride layer 221.

[0093] In this way, the film 220 can be etched without using fluorine (F) radicals. In other words, by using fluorine (F) radicals, it is possible to prevent fluorine (F) from remaining in other films (e.g., the second layer 210).

[0094] Furthermore, by controlling the number of cycles of step S401 and step S402, the amount of etching of the film 220 can be controlled.

[0095] 11 is an example of a graph showing the relationship between temperature and etching amount. The horizontal axis represents the temperature (process temperature) of the substrate W. The vertical axis represents the etching amount per cycle (EPC). Here, the processes of steps S401 and S402 shown in FIG. 5 were repeated a predetermined number of times at each process temperature for polysilicon (Poly), SiCN, a silicon nitride film (PESiN) formed using a plasma ALD method, and a silicon oxide film (Thox) formed by thermal oxidation.

[0096] 11, within the process temperature range of 400° C. to 550° C., the etching depth per cycle (EPC) of film types other than SiCN is sufficiently small, and the etching depth per cycle (EPC) of SiCN is sufficiently large compared to other film types. That is, by the etching step S102 shown in FIG. 5, SiCN can be selectively etched relative to other film types.

[0097] Furthermore, the process temperature range of 400° C. to 550° C. is within the temperature range in which SiN and SiCN films can be formed. This makes it possible to suppress the temperature difference between the process temperature of the deposition step S101 (S103) and the process temperature of the etching step S102. This reduces the time required for temperature adjustment between each step, thereby improving the throughput of the substrate processing apparatus 100.

[0098] The above describes the film formation method of this embodiment using the plasma processing apparatus 100, but the present disclosure is not limited to the above embodiment, etc., and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.

[0099] This application claims priority based on Japanese Patent Application No. 2024-030275, filed on February 29, 2024, the entire contents of which are incorporated herein by reference.

[0100] REFERENCE SIGNS LIST 1 Processing vessel 5 Wafer boat (substrate support section) 20 Gas supply section 30 Plasma generation mechanism (plasma generation section) 60 Control section 100 Plasma processing apparatus (substrate processing apparatus) 211 Recess 220 Film 221 Fluoride layer W Substrate

Claims

1. A substrate processing method comprising the steps of: (a) preparing a film containing silicon (Si) and / or boron (B), carbon (C) and nitrogen (N) on a substrate; (b) supplying a gas containing fluorine (F) to the substrate to fluorinate the film; and (c) supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate to etch the fluorinated film.

2. The substrate processing method according to claim 1, wherein each step of the steps (a), (b), and (c) is repeated multiple times in this order.

3. The substrate processing method according to claim 1, further comprising a step (d) of repeating the steps (b) and (c) a plurality of times, and repeating each step a plurality of times in the order of the step (a) and the step (d).

4. The substrate processing method according to any one of claims 1 to 3, further comprising, before step (a), a step of forming a film containing at least silicon (Si) and / or boron (B) on the substrate.

5. The substrate processing method according to claim 4, wherein the step (a) includes a step of supplying a gas containing carbon (C) to the substrate having a film containing silicon (Si) and / or boron (B), and nitrogen (N) to carbonize the film.

6. The substrate processing method according to claim 4, wherein the step (a) comprises: a step of supplying a gas containing nitrogen (N) to the substrate having a film containing silicon (Si) and / or boron (B) to nitride the film; and a step of supplying a gas containing carbon (C) to the substrate to carbonize the film.

7. The substrate processing method according to claim 5, further comprising the step of forming a film containing at least silicon (Si) and / or boron (B) on the substrate after the step (c).

8. The substrate processing method according to claim 6, further comprising the step of forming a film containing at least silicon (Si) and / or boron (B) on the substrate after the step (c).

9. The substrate processing method according to claim 1, wherein the step (a) includes a step of forming a film containing silicon (Si) and / or boron (B), carbon (C) and nitrogen (N) on the substrate, and after the step (a), the steps (b) and (c) are repeated a plurality of times.

10. The substrate processing method according to claim 9, further comprising the step of forming a film containing at least silicon (Si) and / or boron (B) on the substrate after the step (c).

11. The substrate processing method according to any one of claims 1 to 3, wherein the substrate processing temperature in steps (b) and (c) is within a range of 400°C to 550°C.

12. The substrate processing method according to any one of claims 1 to 3, wherein the substrate processing temperature in steps (a), (b), and (c) is within a range of 400°C to 550°C.

13. The fluorine (F)-containing gas is HF gas, F ２ Gas, ClF ３ Gas, NF ３ Gas, CH ３ F gas, CHF ３ Gas, CF ４ Gas, C ４ F ６ The substrate processing method according to claim 1 , wherein the gas is a gas.

14. The gas containing hydrogen (H) and / or nitrogen (N) is NH ３ , H ２ , H ２ and N ２ The substrate processing method according to claim 1 , wherein the mixed gas is any one of the following gases:

15. A substrate processing method comprising: (a) preparing a film containing silicon (Si) and / or boron (B) and nitrogen (N) on a substrate; (b) supplying a gas containing carbon (C) and fluorine (F) to the substrate to carbonize and fluorinate the film; and (c) supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate to etch the fluorinated film.

16. A substrate processing apparatus comprising: a substrate support part that supports a substrate; a processing vessel that houses the substrate support part; a gas supply part that supplies gas to the processing vessel; a plasma generation part that generates plasma of the gas; and a control part, wherein the control part performs the steps of: (a) preparing a film containing silicon (Si) and / or boron (B), carbon (C) and nitrogen (N) on a substrate; (b) fluorinating the film by supplying a gas containing fluorine (F) to the substrate; and (c) etching the fluorinated film by supplying a plasma of a gas containing hydrogen (H) and / or nitrogen (N) to the substrate.

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