Substrate processing method and plasma processing device

Abstract

Provided are a substrate processing method and a plasma processing device for selectively etching a film containing silicon while reducing the environmental impact.　The substrate processing method comprises: (a) a step for providing a substrate on a substrate support inside a plasma processing chamber, the substrate having a first region constituted of a film containing silicon and nitrogen, and a second region constituted of a film containing silicon, and carbon and / or oxygen; (b) a step for exposing the substrate to first plasma generated from a first processing gas containing a first hydrogen-containing gas; and (c) a step for exposing the substrate to a second processing gas containing a mixed gas or a single gas containing fluorine and hydrogen, or exposing the substrate to second plasma generated from the second processing gas.

Description

Substrate processing method and plasma processing apparatus

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

[0002] Patent Document 1 discloses a method for selectively etching a first region formed from silicon nitride relative to a second region formed from silicon oxide, the method including the steps of: preparing a workpiece having the first region and the second region in a chamber provided by a chamber body of a plasma processing apparatus; generating plasma of a first gas including a gas containing hydrogen in the chamber so as to modify a part of the first region with activated hydrogen species to form a modified region; and generating plasma of a second gas including a gas containing fluorine in the chamber so as to remove the modified region with activated fluorine species.

[0003] JP 2018-98480 A

[0004] In one aspect, the present disclosure provides a substrate processing method and a plasma processing apparatus for selectively etching a silicon-containing film while reducing the environmental load.

[0005] In order to solve the above problem, according to one aspect, there is provided a substrate processing method comprising the steps of: (a) providing a substrate on a substrate support in a plasma processing chamber, the substrate having a first region composed of a film containing silicon and nitrogen and a second region composed of a film containing silicon and carbon and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas containing a first hydrogen-containing gas; and (c) exposing the substrate to a second process gas containing a single gas or a mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas.

[0006] According to one aspect, it is possible to provide a substrate processing method and a plasma processing apparatus that selectively etch a silicon-containing film while reducing the environmental load.

[0007] An example of a diagram for explaining an example of the configuration of a plasma processing system. An example of a diagram for explaining an example of the configuration of an inductively coupled plasma processing apparatus. A flowchart showing an example of a substrate processing method. An example of a schematic cross-sectional view of a substrate used in the substrate processing method. An example of a schematic cross-sectional view of a substrate used in the substrate processing method. Another example of a schematic cross-sectional view of a substrate used in the substrate processing method. Another example of a schematic cross-sectional view of a substrate used in the substrate processing method. A graph showing an example of an etching rate for a film containing silicon and nitrogen. An example of a graph showing an etching selectivity. A graph showing an example of an etching rate for a film containing silicon and carbon. An example of a graph showing an etching selectivity.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] [Plasma Processing System] FIG. 1 is an example diagram illustrating an example configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (see FIG. 2), which will be described later, and the gas exhaust port is connected to an exhaust system 40 (see FIG. 2), which will be described later. The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0010] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0012] The following describes an example of the configuration of an inductively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is an example of a diagram for explaining an example of the configuration of an inductively coupled plasma processing apparatus.

[0013] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. The plasma processing apparatus 1 also includes a substrate support 11, a gas inlet, and an antenna 14. The substrate support 11 is disposed within the plasma processing chamber 10. The antenna 14 is disposed on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, a sidewall 102 of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded.

[0014] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0015] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a bias electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple bias electrodes. Alternatively, the electrostatic electrode 1111b may function as a bias electrode. Therefore, the substrate support 11 includes at least one bias electrode.

[0016] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0017] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0018] The gas inlet is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the gas inlet includes a center gas injector (CGI) 13. The center gas injector 13 is disposed above the substrate support 11 and attached to a central opening formed in the dielectric window 101. The center gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet port 13c. The process gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas inlet port 13c. Note that the gas inlet may include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 102 in addition to or instead of the center gas injector 13.

[0019] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the gas inlet through a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0020] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one bias electrode and the antenna 14. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generating unit 12. Furthermore, by supplying a bias RF signal to the at least one bias electrode, a bias potential is generated on the substrate W, thereby attracting ions in the formed plasma to the substrate W.

[0021] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to the antenna 14 via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0022] The second RF generator 31b is coupled to at least one bias electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one bias electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0023] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a bias DC generator 32a. In one embodiment, the bias DC generator 32a is connected to at least one bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to the at least one bias electrode.

[0024] In various embodiments, the bias DC signal may be pulsed. In this case, a sequence of voltage pulses is applied to at least one bias electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the bias DC generator 32a and at least one bias electrode. Thus, the bias DC generator 32a and the waveform generator constitute a voltage pulse generator. The voltage pulses may have positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. Note that the bias DC generator 32a may be provided in addition to the RF power supply 31 or may be provided instead of the second RF generator 31b.

[0025] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the RF power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generator may be connected to both the outer coil and the inner coil, or separate RF generators may be connected to the outer coil and the inner coil separately.

[0026] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0027] While FIG. 2 illustrates an inductively coupled plasma processing apparatus 1, the present invention is not limited to this and may also be a capacitively coupled plasma processing apparatus. A capacitively coupled plasma processing apparatus includes a lower electrode provided on a substrate support and an upper electrode provided opposite the substrate support. In this case, the first RF generator is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. Other configurations are similar, and redundant description will be omitted.

[0028] [Substrate Processing Method According to First Embodiment] Next, an example of a substrate processing method according to a first embodiment will be described with reference to Figures 3 to 5B. Figure 3 is a flowchart showing an example of the substrate processing method. Here, the substrate W has a first region and a second region. In the substrate processing method according to the first embodiment, the first region is selectively etched relative to the second region.

[0029] In step S101, a substrate W having a first region and a second region is provided. Here, the control unit 2 controls a transfer device (not shown) to transfer the substrate W having the first region and the second region into the plasma processing chamber 10 and place it on the substrate support 11. Then, the control unit 2 controls the power supply to supply power to the electrostatic electrode 1111b. As a result, the substrate W is electrostatically attracted to the substrate support 11.

[0030] An example of a substrate W will now be described with reference to Figures 4A and 4B. Figures 4A and 4B are example cross-sectional views of a substrate W used in the substrate processing method. Figure 4A is an example cross-sectional view of a substrate W provided in step S101. Figure 4B is an example cross-sectional view of a substrate W after completion of the etching process shown in Figure 3.

[0031] In the example shown in FIG. 4A, the substrate W has a first film 211 as a first region, a second film 212 as a second region, and a third film 213.

[0032] 4A, a second film 212 (second region) is formed over the entire substrate W. The second film 212 is a film different from the first film 211. For example, the second film 212 is made of a film containing silicon (Si), carbon (C) and / or oxygen (O). Specifically, the second film 212 is made of a material such as SiC, SiO ２ , SiOC, etc. The second film 212 may be a film containing other elements in addition to silicon (Si), carbon (C), and oxygen (O).

[0033] A third film 213 having a recess such as a hole trench formed therein is formed on the upper surface of the second film 212. The recess formed in the third film 213 reaches the upper surface of the second film 212. The third film 213 is, for example, a Si film.

[0034] A first film 211 (first region) is formed so as to cover the upper surface of the third film 213 and the side and bottom surfaces of the recess formed in the third film 213. For example, the first film 211 is made of a film containing silicon (Si) and nitrogen (N). Specifically, the first film 211 may be a film of any of SiN, SiON, etc. Note that the first film 211 may be a film containing other elements in addition to silicon (Si) and nitrogen (N).

[0035] 3, the first film 211 (first region) is selectively etched relative to the second film 212 (second region), resulting in the first film 211 (first region) being removed by etching, as shown in FIG.

[0036] The configuration of the substrate W is not limited to this. Another example of the substrate W will be described with reference to Figures 5A and 5B. Figures 5A and 5B are another example of a schematic cross-sectional view of a substrate used in the substrate processing method. Specifically, Figure 5A is an example of a schematic cross-sectional view of the substrate W provided in step S101. Figure 5B is an example of a schematic cross-sectional view of the substrate W after the etching process shown in Figure 3 is completed.

[0037] In the example shown in FIG. 5A, the substrate W has a first film 221 as a first region, a second film 222 as a second region, and a third film 220.

[0038] 5A, the third film 220 is formed over the entire substrate W. The third film 220 is, for example, a Si film.

[0039] A first film 221 and a second film 222 are formed on the upper surface of the third film 220 .

[0040] The first film 221 is composed of a film containing silicon (Si) and nitrogen (N). Specifically, the first film 221 may be a film of any of SiN, SiON, etc. Note that the first film 221 may be a film containing other elements in addition to silicon (Si) and nitrogen (N).

[0041] The second film 222 is made of a film containing silicon (Si), carbon (C) and / or oxygen (O). Specifically, the second film 222 is made of a material selected from the group consisting of SiC, SiO ２, SiOC, etc. The second film 222 may be a film containing other elements in addition to silicon (Si), carbon (C), and oxygen (O).

[0042] 3, the first film 221 (first region) is selectively etched relative to the second film 222 (second region), resulting in the first film 221 (first region) being removed by etching, as shown in FIG.

[0043] 3 , in step S102, a first process gas is supplied to the substrate W to form a modified layer in the first region. Here, the control unit 2 controls the gas supply unit 20 to supply the first process gas to the plasma processing space 10s. The control unit 2 also controls the first RF generator 31a to supply a source RF signal (source RF power) for plasma generation to the antenna 14, thereby generating plasma of the first process gas in the plasma processing space 10s. This exposes the substrate W to the plasma generated from the first process gas.

[0044] In addition, in a capacitively coupled plasma processing apparatus, the control unit 2 controls the first RF generating unit 31a to supply a source RF signal (source RF power) for plasma generation to the lower electrode and / or the upper electrode, thereby generating plasma of the first processing gas in the plasma processing space 10s.

[0045] Here, the first processing gas is a modifying gas that modifies the surface of the first region, which is a film containing silicon (Si) and nitrogen (N). The first processing gas includes a first hydrogen-containing gas. The first hydrogen-containing gas is a gas containing hydrogen (H). Specifically, the first hydrogen-containing gas is H ２ , C.H. ４ , N.H. ３ At least one selected from the group consisting of:

[0046] By exposing the substrate W to plasma of a first processing gas containing a first hydrogen-containing gas, the surface of the first region (first film 211, 221), which is a film containing silicon (Si) and nitrogen (N), is modified to form a modified layer.

[0047] Furthermore, in step S102, the control unit 2 may control the second RF generation unit 31b and / or the bias DC generation unit 32a to supply a bias signal (bias RF signal and / or bias DC signal) to the bias electrode (base 1110). As a result, hydrogen ions generated by the plasma of the first processing gas are caused to perpendicularly impinge on the substrate W by the bias signal supplied to the bias electrode (base 1110). The hydrogen ions then impinge on and react with the first region formed of a film containing silicon (Si) and nitrogen (N), thereby forming a modified layer.

[0048] In step S102, it is not necessary to supply a bias signal (bias RF signal, bias DC signal) to the bias electrode (base 1110).

[0049] In step S103, a second process gas is supplied to the substrate W to remove (etch) the modified layer formed in the first region. Here, the control unit 2 controls the gas supply unit 20 to supply the second process gas to the plasma processing space 10s. The control unit 2 also controls the first RF generator 31a to supply a source RF signal (source RF power) for plasma generation to the lower electrode and / or upper electrode, thereby generating plasma of the second process gas in the plasma processing space 10s. This exposes the substrate W to the plasma generated from the second process gas.

[0050] In addition, in a capacitively coupled plasma processing apparatus, the control unit 2 controls the first RF generating unit 31a to supply a source RF signal (source RF power) for plasma generation to the lower electrode and / or the upper electrode, thereby generating plasma of the second processing gas in the plasma processing space 10s.

[0051] In step S103, the bias signal (bias RF signal, bias DC signal) does not have to be supplied to the bias electrode (base 1110). In step S103, the control unit 2 may control the second RF generation unit 31b and / or the bias DC generation unit 32a to supply the bias signal (bias RF signal and / or bias DC signal) to the bias electrode (base 1110).

[0052] In addition, in step S103, the substrate W is exposed to plasma generated from the second process gas, but this is not limiting. Here, the control unit 2 controls the gas supply unit 20 to supply the second process gas to the plasma processing space 10s. In this way, the substrate W may be exposed to the second process gas.

[0053] The second process gas is an etching gas that etches the modified layer in the first region formed in step S102. The second process gas includes a single gas containing fluorine (F) and hydrogen (H), or a mixed gas.

[0054] The simple gas containing fluorine (F) and hydrogen (H) may be a linear hydrofluorocarbon gas having unsaturated bonds between carbon atoms. The simple gas containing fluorine (F) and hydrogen (H) may also be a hydrofluorocarbon gas having double bonds between carbon atoms. These gases have a relatively low global warming potential (GWP), and are therefore effective in reducing the greenhouse effect.

[0055] Specifically, a single gas containing fluorine (F) and hydrogen (H) is ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４ At least one selected from the group consisting of:

[0056] The mixed gas containing fluorine (F) and hydrogen (H) includes a fluorine-containing gas and a second hydrogen-containing gas.

[0057] The fluorine-containing gas is C ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ , C ３ H ２ F ４ The gas is at least one selected from the group consisting of: HCl, HCl, HCl(OH), HCl(CO ...

[0058] The second hydrogen-containing gas is a gas containing hydrogen (H). Specifically, the second hydrogen-containing gas is H ２ , C.H. ４ , N.H. ３ etc. The second hydrogen-containing gas may be the same gas as the first hydrogen-containing gas or may be a different gas.

[0059] The second process gas may further contain an oxygen-containing gas. The oxygen-containing gas is a gas containing oxygen (O). Specifically, the oxygen-containing gas is O ２ , CO, CO ２ , O ３ , H ２ O, H ２ O ２ At least one selected from the group consisting of:

[0060] Furthermore, the second process gas may further contain a rare gas (for example, Ar gas).

[0061] Here, the process shown in step S103 includes a process of generating HF species in the plasma processing chamber 10 and a process of removing the modified layer by reacting the modified layer with the HF species.

[0062] In the step of generating HF species in the plasma processing chamber 10, the HF species are generated from a second processing gas. The HF species include at least one of hydrogen fluoride (HF) gas, radicals, and ions. When a single gas containing fluorine (F) and hydrogen (H) is used as the second processing gas, the HF species are generated by dissociation of the single gas containing fluorine (F) and hydrogen (H) in the plasma processing chamber 10. When a mixed gas of a fluorine-containing gas and a second hydrogen-containing gas is used as the second processing gas, the HF species are generated by reaction of the mixed gas of the fluorine-containing gas and the second hydrogen-containing gas in the plasma processing chamber 10. The HF species may be generated using plasma or without plasma.

[0063] In the step of removing the modified layer, the modified layer in the first region formed in step S102 is removed (etched) by reaction with the generated HF species.

[0064] Although the second processing gas has been described as a gas that generates HF species within the plasma processing chamber 10, this is not limited to this, and the configuration may also be such that HF ​​gas is supplied into the plasma processing chamber 10 as the second processing gas.

[0065] In step S104, it is determined whether the processing of steps S102 to S103 has been repeated a predetermined number of times. If the processing has not been repeated the predetermined number of times (S104: NO), the processing of the control unit 2 returns to step S102, and the processing of steps S102 to S103 is repeated. If the processing has not been repeated the predetermined number of times, the processing of the control unit 2 returns to step S102, and the processing of steps S102 to S103 is repeated. If the processing has been repeated the predetermined number of times (S104: YES), the processing of the control unit 2 shown in FIG. 3 ends.

[0066] In this way, by repeating the process of forming a modified layer in the first region and the process of removing the modified layer, the first region can be selectively removed relative to the second region.

[0067] 6 is a graph showing an example of an etching rate for a film containing silicon (Si) and nitrogen (N). Here, Si is used as the film containing silicon (Si) and nitrogen (N). ３ N ４ The vertical axis represents the etching rate. (a) represents the case where only the process of step S102 was performed, (b) represents the case where only the process of step S103 was performed, and (c) represents the case where the processes of step S102 and step S103 were repeated.

[0068] As shown by comparing (c) with (a) and (b) in FIG. 6, by repeating the processes of step S102 and step S103 (S104), a film containing silicon (Si) and nitrogen (N) can be etched.

[0069] FIG. 7 is an example of a graph showing the etching selectivity. Here, the horizontal axis indicates the number of repetitions, and the vertical axis indicates the etching amount. Here, SiN, SiC, and SiO ２ The substrate was subjected to an etching process according to the flow chart shown in FIG.

[0070] As shown in FIG. 7, the etching process shown in FIG. 3 ２ It is possible to etch SiN selectively to Si.

[0071] In addition, HF and C used as the second processing gas ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F６ and C ３ H ２ F ４ (where x in the chemical formula represents a natural number) ６ , N.F. ３ , C.F. ４ , CHF ３ The gas has a lower global warming potential (GWP) than etching gases such as SiO 2 , SiO 2 , etc. In this way, the etching process shown in FIG. 3 can selectively etch a film containing silicon (Si) and nitrogen (N) while reducing the environmental load.

[0072] [Substrate Processing Method According to Second Embodiment] Next, an example of a substrate processing method according to a second embodiment will be described with reference to FIGS. 3 to 5B. FIG. 3 is a flowchart showing an example of the substrate processing method. Here, the substrate W has a first region and a second region. In the substrate processing method according to the second embodiment, the first region is selectively etched relative to the second region. Note that the substrate processing method according to the second embodiment differs from the substrate processing method according to the first embodiment in the type of film that is selectively etched.

[0073] In step S101, a substrate W having a first region and a second region is provided. Here, the control unit 2 controls a transfer device (not shown) to transfer the substrate W having the first region and the second region into the plasma processing chamber 10 and place it on the substrate support 11. Then, the control unit 2 controls the power supply to supply power to the electrostatic electrode 1111b. As a result, the substrate W is electrostatically attracted to the substrate support 11.

[0074] The first region (for example, the first films 211, 221 shown in FIGS. 4A to 5B) is made of a film containing silicon (Si) and carbon (C). Specifically, the first region is a film of SiC, SiOC, or the like. Note that the first region may be a film containing other elements in addition to silicon (Si) and carbon (C).

[0075] The second region (for example, the second films 212 and 222 shown in FIGS. 4A to 5B) is made of a film containing silicon (Si), nitrogen (N) and / or oxygen (O). Specifically, the second region is made of a film containing SiN, SiO ２, SiON, etc. The second region may be a film containing other elements in addition to silicon (Si), nitrogen (N), and oxygen (O).

[0076] The third film 213 shown in FIGS. 4A and 4B and the third film 220 shown in FIGS. 5A and 5B are, for example, Si films.

[0077] In step S102, a first process gas is supplied to the substrate W to form a modified layer in the first region. Here, the control unit 2 controls the gas supply unit 20 to supply the first process gas to the plasma processing space 10s. The control unit 2 also controls the first RF generator 31a to supply a source RF signal (source RF power) for plasma generation to the antenna 14, thereby generating plasma of the first process gas in the plasma processing space 10s. This exposes the substrate W to the plasma generated from the first process gas.

[0078] In addition, in a capacitively coupled plasma processing apparatus, the control unit 2 controls the first RF generating unit 31a to supply a source RF signal (source RF power) for plasma generation to the lower electrode and / or the upper electrode, thereby generating plasma of the first processing gas in the plasma processing space 10s.

[0079] Here, the first processing gas is a modifying gas that modifies the surface of the first region, which is a film containing silicon (Si) and carbon (C). The first processing gas includes a nitrogen-containing gas. The nitrogen-containing gas is a gas containing nitrogen (N). Specifically, the nitrogen-containing gas is N ２ , NO, NO ２ , HNO, NH ３ At least one selected from the group consisting of:

[0080] By exposing the substrate W to plasma of a first processing gas containing a nitrogen-containing gas, the surface of the first region (first film 211, 221), which is a film containing silicon (Si) and carbon (C), is modified to form a modified layer.

[0081] Furthermore, in step S102, the control unit 2 may control the second RF generation unit 31b and / or the bias DC generation unit 32a to supply a bias signal (bias RF signal and / or bias DC signal) to the bias electrode (base 1110). As a result, the bias signal supplied to the bias electrode (base 1110) causes nitrogen ions generated by the plasma of the first processing gas to be incident on the substrate W in a vertical direction. The nitrogen ions then enter and react with the first region formed of a film containing silicon (Si) and carbon (C), thereby forming a modified layer.

[0082] In step S102, it is not necessary to supply a bias signal (bias RF signal, bias DC signal) to the bias electrode (base 1110).

[0083] In step S103, a second process gas is supplied to the substrate W to remove (etch) the modified layer formed in the first region. Here, the control unit 2 controls the gas supply unit 20 to supply the second process gas to the plasma processing space 10s. The control unit 2 also controls the first RF generator 31a to supply a source RF signal (source RF power) for plasma generation to the lower electrode and / or upper electrode, thereby generating plasma of the second process gas in the plasma processing space 10s. This exposes the substrate W to the plasma generated from the second process gas.

[0084] In addition, in a capacitively coupled plasma processing apparatus, the control unit 2 controls the first RF generating unit 31a to supply a source RF signal (source RF power) for plasma generation to the lower electrode and / or the upper electrode, thereby generating plasma of the second processing gas in the plasma processing space 10s.

[0085] In step S103, the bias signal (bias RF signal, bias DC signal) does not have to be supplied to the bias electrode (base 1110). In step S103, the control unit 2 may control the second RF generation unit 31b and / or the bias DC generation unit 32a to supply the bias signal (bias RF signal and / or bias DC signal) to the bias electrode (base 1110).

[0086] In addition, in step S103, the substrate W is exposed to plasma generated from the second process gas, but this is not limiting. Here, the control unit 2 controls the gas supply unit 20 to supply the second process gas to the plasma processing space 10s. In this way, the substrate W may be exposed to the second process gas.

[0087] The second process gas is an etching gas that etches the modified layer in the first region formed in step S102. The second process gas includes a single gas containing fluorine (F) and hydrogen (H), or a mixed gas.

[0088] A single gas containing fluorine (F) and hydrogen (H) is C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４ At least one selected from the group consisting of:

[0089] The mixed gas containing fluorine (F) and hydrogen (H) includes a fluorine-containing gas and a hydrogen-containing gas.

[0090] The fluorine-containing gas is a gas containing fluorine (F). Specifically, the fluorine-containing gas is C ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３F, C ４ H ２ F ６ , C ３ H ２ F ４ etc., where x in the chemical formula represents a natural number.

[0091] The hydrogen-containing gas is a gas containing hydrogen (H). Specifically, the hydrogen-containing gas is H ２ , C.H. ４ , N.H. ３ At least one selected from the group consisting of:

[0092] The second process gas may further contain an oxygen-containing gas. The oxygen-containing gas is a gas containing oxygen (O). Specifically, the oxygen-containing gas is O ２ , CO, CO ２ , O ３ , H ２ O, H ２ O ２ At least one selected from the group consisting of:

[0093] Furthermore, the second process gas may further contain a rare gas (for example, Ar gas).

[0094] Here, the process shown in step S103 includes a process of generating HF species in the plasma processing chamber 10 and a process of removing the modified layer by reacting the modified layer with the HF species.

[0095] In the step of generating HF species in the plasma processing chamber 10, the HF species are generated from the second processing gas. The HF species include at least one of hydrogen fluoride (HF) gas, radicals, and ions. When a single gas containing fluorine (F) and hydrogen (H) is used as the second processing gas, the HF species are generated by dissociation of the single gas containing fluorine (F) and hydrogen (H) in the plasma processing chamber 10. When a mixed gas of a fluorine-containing gas and a hydrogen-containing gas is used as the second processing gas, the HF species are generated by reaction of the mixed gas of the fluorine-containing gas and the hydrogen-containing gas in the plasma processing chamber 10. The HF species may be generated using plasma or without plasma.

[0096] In the step of removing the modified layer, the modified layer in the first region formed in step S102 is removed (etched) by reaction with the generated HF species.

[0097] Although the second processing gas has been described as a gas that generates HF species within the plasma processing chamber 10, this is not limited to this, and the configuration may also be such that HF ​​gas is supplied into the plasma processing chamber 10 as the second processing gas.

[0098] In step S104, it is determined whether the processing of steps S102 to S103 has been repeated a predetermined number of times. If the processing has not been repeated the predetermined number of times (S104: NO), the processing of the control unit 2 returns to step S102, and the processing of steps S102 to S103 is repeated. If the processing has not been repeated the predetermined number of times, the processing of the control unit 2 returns to step S102, and the processing of steps S102 to S103 is repeated. If the processing has been repeated the predetermined number of times (S104: YES), the processing of the control unit 2 shown in FIG. 3 ends.

[0099] In this way, by repeating the process of forming a modified layer in the first region and the process of removing the modified layer, the first region can be selectively removed relative to the second region.

[0100] 8 is a graph showing an example of the etching rate for a film containing silicon (Si) and carbon (C). Here, a SiC film was used as the film containing silicon (Si) and carbon (C). The vertical axis represents the etching rate. (a) shows the case where only the process of step S102 was performed, (b) shows the case where only the process of step S103 was performed, and (c) shows the case where the processes of step S102 and step S103 were repeated.

[0101] As shown by comparing (c) with (a) and (b) in FIG. 8, by repeating the processes of step S102 and step S103 (S104), a film containing silicon (Si) and carbon (C) can be etched.

[0102] FIG. 9 is an example of a graph showing the etching selectivity. Here, the horizontal axis represents the number of repetitions, and the vertical axis represents the etching amount. Here, SiN, SiC, and SiO ２ The substrate was subjected to an etching process according to the flow chart shown in FIG.

[0103] As shown in FIG. 9, according to the etching process shown in FIG. 3, SiN, SiO ２ It is possible to etch SiC selectively to Si.

[0104] In addition, HF and C used as the second processing gas ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４ (where x in the chemical formula represents a natural number) ６ , N.F. ３ , C.F. ４ , CHF ３ The gas has a lower global warming potential (GWP) than etching gases such as SiO 2 , SiO 2 , etc. In this way, the etching process shown in FIG. 3 can selectively etch a film containing silicon (Si) and carbon (C) while reducing the environmental load.

[0105] The gas pipes in the gas supply unit 20 are made of a metal material that is corrosion-resistant to the process gas. Specifically, the gas pipes are preferably made of a metal material such as SUS316 or Hastelloy (registered trademark).

[0106] 3, a process of forming a precoat film on at least a portion of the interior of the plasma processing chamber 10 may be performed. This prevents the wall surfaces and other surfaces within the plasma processing chamber 10 from being corroded by the processing gas. The precoat film may be, for example, a thermal sprayed film formed by thermal spraying. Alternatively, the precoat film may be, for example, a film formed by a film-forming gas supplied into the plasma processing chamber 10.

[0107] The embodiments disclosed above include, for example, the following aspects. (Supplementary Note 1) A substrate processing method comprising: (a) providing a substrate on a substrate support in a plasma processing chamber, the substrate having a first region composed of a film containing silicon and nitrogen and a second region composed of a film containing silicon and carbon and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas containing a first hydrogen-containing gas; and (c) exposing the substrate to a second process gas containing a single gas or mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas. (Supplementary Note 2) The substrate processing method according to Supplementary Note 1, wherein the single gas containing fluorine and hydrogen is a linear hydrofluorocarbon gas having unsaturated bonds between carbon atoms. (Supplementary Note 3) The single gas containing fluorine and hydrogen is a C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４The substrate processing method according to claim 1 or 2, wherein the mixed gas containing fluorine and hydrogen is a mixed gas containing a fluorine-containing gas and a second hydrogen-containing gas, and the fluorine-containing gas is at least one selected from the group consisting of C ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ , C ３ H ２ F ４ (wherein x in the chemical formula represents a natural number), and the second hydrogen-containing gas is at least one selected from the group consisting of H ２ , C.H. ４ , N.H. ３ The substrate processing method according to claim 1, wherein the second processing gas is at least one selected from the group consisting of: (Supplementary Note 5) The substrate processing method according to any one of Supplementary Note 1 to Supplementary Note 4, wherein the second processing gas further contains an oxygen-containing gas. (Supplementary Note 6) The oxygen-containing gas is O ２ , CO, CO ２ , O ３ , H ２ O, H ２ O ２ The substrate processing method according to claim 5, wherein the first hydrogen-containing gas is at least one selected from the group consisting of H ２ , C.H. ４ , N.H. ３(Supplementary Note 8) The substrate processing method according to any one of Supplementary Note 1 to Supplementary Note 7, further comprising a step of repeating steps (b) and (c), which form one cycle. (Supplementary Note 9) The substrate processing method according to any one of Supplementary Note 1 to Supplementary Note 8, further comprising a step of repeating steps (b) and (c), which form one cycle. (Supplementary Note 10) The substrate processing method according to Supplementary Note 9, wherein step (b) comprises forming a modified layer in the first region of the substrate. (Supplementary Note 11) The substrate processing method according to Supplementary Note 10, wherein step (c) comprises removing the modified layer formed in the first region. (Supplementary Note 11) The substrate processing method according to Supplementary Note 10, wherein step (c) comprises: (c1) generating HF species in the plasma processing chamber; and (c2) removing the modified layer in the first region by a reaction between the HF species and the modified layer. (Supplementary Note 12) The substrate processing method according to any one of Supplementary Notes 1 to 11, wherein the step (b) comprises supplying RF power for plasma generation to an antenna disposed above the substrate support or an upper electrode disposed opposite the substrate support. (Supplementary Note 13) The substrate processing method according to any one of Supplementary Notes 1 to 12, further comprising, before the step (a), a step of forming a precoat film on at least a part of the plasma processing chamber. (Supplementary Note 14) A substrate processing method comprising: (a) providing a substrate on a substrate support in a plasma processing chamber, the substrate having a first region composed of a film containing silicon and carbon and a second region composed of a film containing silicon and nitrogen and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas containing a nitrogen-containing gas; and (c) exposing the substrate to a second process gas containing a single gas or a mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas. (Supplementary Note 15) The substrate processing method according to Supplementary Note 14, wherein the single gas containing fluorine and hydrogen is a linear hydrofluorocarbon gas having an unsaturated bond. (Supplementary Note 16) The single gas containing fluorine and hydrogen is a C ２ H ２ F ２ , C ２ HF ３ , C２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４ The substrate processing method according to claim 14 or 15, wherein the mixed gas containing fluorine and hydrogen is a mixed gas containing a fluorine-containing gas and a second hydrogen-containing gas, and the fluorine-containing gas is at least one selected from the group consisting of C ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ , C ３ H ２ F ４ (wherein x in the chemical formula represents a natural number), and the second hydrogen-containing gas is at least one selected from the group consisting of H ２ , C.H. ４ , N.H. ３ The substrate processing method according to claim 14, wherein the nitrogen-containing gas is at least one selected from the group consisting of N ２ , NO, NO ２ , HNO, NH ３(a) placing a substrate on the substrate support in the plasma processing chamber, the substrate having a first region made of a film containing silicon and nitrogen and a second region made of a film containing silicon, carbon and / or oxygen, on the substrate support, (b) exposing the substrate to a first plasma generated from a first process gas containing a first hydrogen-containing gas, and (c) exposing the substrate to a second process gas containing a single gas or a mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas. (Supplementary Note 20) A plasma processing apparatus comprising: a plasma processing chamber; a substrate support within the plasma processing chamber; a gas supply unit for supplying a process gas into the plasma processing chamber; a plasma generation unit for generating plasma from the process gas in the plasma processing chamber; and a controller, wherein the controller is configured to perform a process including the steps of: (a) placing a substrate on the substrate support within the plasma processing chamber, the substrate having a first region composed of a film containing silicon and carbon and a second region composed of a film containing silicon and nitrogen and / or oxygen, (b) exposing the substrate to a first plasma generated from a first process gas containing a nitrogen-containing gas, and (c) exposing the substrate to a second process gas containing a single gas or a mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas. (Supplementary Note 21) The plasma processing apparatus according to Supplementary Note 19 or Supplementary Note 20, wherein piping of the gas supply unit through which the process gas flows is made of a corrosion-resistant metallic material.

[0108] The present invention is not limited to the configurations described in the above embodiments, but may be combined with other elements, etc. These aspects can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form.

[0109] This application claims priority based on Japanese Patent Application No. 2024-135687, filed on August 15, 2024, the entire contents of which are incorporated herein by reference.

[0110] REFERENCE SIGNS LIST 1 Plasma processing apparatus 2 Control unit 10 Plasma processing chamber 10s Plasma processing space 11 Substrate support unit 13 Central gas injection unit 14 Antenna 20 Gas supply unit 30 Power supply 40 Exhaust system 211, 221 First film (first region) 212, 222 Second film (second region) W Substrate

Claims

1. A method of processing a substrate, comprising: (a) providing a substrate on a substrate support in a plasma processing chamber, the substrate having a first region comprised of a film comprising silicon and nitrogen and a second region comprised of a film comprising silicon and carbon and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas comprising a first hydrogen-containing gas; and (c) exposing the substrate to a second process gas comprising a gas or gas mixture comprising fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas.

2. The substrate processing method according to claim 1, wherein the single gas containing fluorine and hydrogen is a linear hydrofluorocarbon gas having unsaturated bonds between carbon atoms.

3. The single gas containing fluorine and hydrogen is C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４ The substrate processing method according to claim 1 , wherein the solvent is at least one selected from the group consisting of:

4. The mixed gas containing fluorine and hydrogen is a mixed gas containing a fluorine-containing gas and a second hydrogen-containing gas, and the fluorine-containing gas is C ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ , C ３ H ２ F ４ (wherein x in the chemical formula represents a natural number), and the second hydrogen-containing gas is at least one selected from the group consisting of H ２ , C.H. ４ , N.H. ３ The substrate processing method according to claim 1 , wherein the solvent is at least one selected from the group consisting of:

5. The substrate processing method according to claim 1, wherein the second processing gas further includes an oxygen-containing gas.

6. The oxygen-containing gas is O ２ , CO, CO ２ , O ３ , H ２ O, H ２ O ２ The substrate processing method according to claim 5 , wherein the solvent is at least one selected from the group consisting of:

7. The first hydrogen-containing gas is H ２ , C.H. ４ , N.H. ３ The substrate processing method according to claim 1 , wherein the solvent is at least one selected from the group consisting of:

8. The substrate processing method according to claim 1, further comprising the step of repeating the steps (b) and (c) as one cycle.

9. The substrate processing method according to claim 1, wherein the step (b) forms a modified layer in the first region of the substrate.

10. The substrate processing method according to claim 9, wherein the step (c) removes the modified layer formed in the first region.

11. The substrate processing method of claim 10, wherein the step (c) comprises: (c1) generating HF species in the plasma processing chamber; and (c2) removing the modified layer in the first region by reacting the modified layer with the HF species.

12. The substrate processing method according to claim 1, wherein the step (b) supplies RF power for generating plasma to an antenna disposed above the substrate support part or an upper electrode disposed opposite the substrate support part.

13. The substrate processing method according to claim 1, further comprising the step of forming a precoat film on at least a portion of the interior of the plasma processing chamber before the step (a).

14. A substrate processing method comprising: (a) providing a substrate on a substrate support in a plasma processing chamber, the substrate having a first region comprised of a film comprising silicon and carbon and a second region comprised of a film comprising silicon and nitrogen and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas comprising a nitrogen-containing gas; and (c) exposing the substrate to a second process gas comprising a single gas or a mixture of gases comprising fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas.

15. The substrate processing method according to claim 14, wherein the single gas containing fluorine and hydrogen is a linear hydrofluorocarbon gas having an unsaturated bond.

16. The single gas containing fluorine and hydrogen is C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ and C ３ H ２ F ４ The substrate processing method according to claim 14 , wherein the solvent is at least one selected from the group consisting of:

17. The mixed gas containing fluorine and hydrogen is a mixed gas containing a fluorine-containing gas and a second hydrogen-containing gas, and the fluorine-containing gas is C ３ F ６ , F ２ , COF ２ , C.F. ３ COF, CO-(CF ３ ) ｘ , (CF ３ )-(CF ２ ) ｘ -COF, ClF ３ , C.F. ３ Cl, IF ７ , XeF ２ , C ２ H ２ F ２ , C ２ HF ３ , C ２ H ３ F, C ４ H ２ F ６ , C ３ H ２ F ４ (wherein x in the chemical formula represents a natural number), and the second hydrogen-containing gas is at least one selected from the group consisting of H ２ , C.H. ４ , N.H. ３ The substrate processing method according to claim 14 , wherein the solvent is at least one selected from the group consisting of:

18. The nitrogen-containing gas is N ２ , NO, NO ２ , HNO, NH ３ The substrate processing method according to claim 14 , wherein the solvent is at least one selected from the group consisting of:

19. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support within the plasma processing chamber; a gas supply unit for supplying a process gas into the plasma processing chamber; a plasma generation unit for generating plasma from the process gas in the plasma processing chamber; and a controller, wherein the controller is configured to perform a process comprising: (a) placing a substrate on the substrate support within the plasma processing chamber, the substrate having a first region composed of a film containing silicon and nitrogen and a second region composed of a film containing silicon, carbon, and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas comprising a first hydrogen-containing gas; and (c) exposing the substrate to a second process gas comprising a single gas or mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas.

20. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support within the plasma processing chamber; a gas supply unit for supplying a process gas into the plasma processing chamber; a plasma generation unit for generating plasma from the process gas in the plasma processing chamber; and a controller, wherein the controller is configured to perform a process comprising: (a) placing a substrate on the substrate support within the plasma processing chamber, the substrate having a first region composed of a film containing silicon and carbon and a second region composed of a film containing silicon, nitrogen, and / or oxygen; (b) exposing the substrate to a first plasma generated from a first process gas comprising a nitrogen-containing gas; and (c) exposing the substrate to a second process gas comprising a single gas or a mixed gas containing fluorine and hydrogen, or exposing the substrate to a second plasma generated from the second process gas.

21. The plasma processing apparatus according to claim 19 or 20, wherein the piping of the gas supply unit through which the processing gas flows is made of a corrosion-resistant metal material.

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