Plasma processing apparatus and plasma processing method

Abstract

The invention provides a plasma processing apparatus and a plasma processing method for reducing roughness of a film formed by plasma processing. The plasma processing apparatus includes a chamber, a substrate support portion, a gas supply portion, a first power source, a second power source, and a control portion, the control portion executes plasma processing repeating a cycle including a first period, a second period, a third period, and a fourth period in this order, and the control portion controls the first power source and the second power source. The control section controls the first power supply such that the generation source RF signal has a first power level in a first period and a second power level less than the first power level and greater than zero power level in a second period, and controls the second power supply such that the bias signal has a fifth power level greater than zero power level in the second period. There is a sixth power level greater than the fifth power level during the fourth period.

Description

Technical Field

[0001] Exemplary embodiments of the present invention relate to a plasma processing apparatus and a plasma processing method. Background Art

[0002] As a technique for etching a region composed of silicon oxide, there is an etching method described in Patent Document 1.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-173240 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a technique for reducing the roughness of a film formed by plasma treatment.

[0008] Technical solutions to technical problems

[0009] A plasma processing apparatus in an exemplary embodiment of the present invention includes: a chamber; a substrate support portion arranged in the chamber; a gas supply portion for supplying a process gas into the chamber; a first power supply for supplying a generation source RF signal to the chamber to generate plasma from the process gas in the chamber; a second power supply for supplying a bias signal to the substrate support portion; and a control portion, wherein the control portion performs plasma processing, the plasma processing repeatedly performing a cycle including a first period, a second period, a third period, and a fourth period, controls the first power supply so that the generation source RF signal has a first power level in the first period, a second power level that is less than the first power level and greater than zero power level in the second period, a third power level that is less than the first power level and greater than zero power level in the third period, and a fourth power level that is less than the first power level and greater than zero power level in the fourth period, and controls the second power supply so that the bias signal has a fifth power level that is greater than zero power level in the second period, and a sixth power level that is greater than the fifth power level in the fourth period.

[0010] Effects of the Invention

[0011] According to an exemplary embodiment of the present invention, a technique for reducing the roughness of a film formed by plasma treatment can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram for explaining a configuration example of a plasma processing system.

[0013] Figure 2This is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0014] Figure 3 It is a diagram for explaining the structure of a plasma processing apparatus in one embodiment.

[0015] Figure 4 1 is a diagram showing an example of supply of a generation source RF signal and a bias RF signal in each cycle.

[0016] Figure 5 This is an explanatory diagram illustrating an example of a film on a substrate before etching.

[0017] Figure 6 It is an explanatory diagram for explaining an example of the state of the film on the substrate in the first period, the second period, the third period, and the fourth period.

[0018] Figure 7 This is an explanatory diagram illustrating an example of a film on a substrate after etching.

[0019] Figure 8 It is a mathematical formula that describes the relationship between the incident angle θ of ions onto the film on the substrate and the temperature Ti of the ions.

[0020] Figure 9 This is a graph showing the results of comparing the ratio of CC bonds (carbon bonds) in the protective film on the mask when a bias RF signal is supplied to the substrate support part in the second period and the ratio of CC bonds in the protective film on the mask when no bias RF signal is supplied to the substrate support part.

[0021] Figure 10 This is a graph showing the results of verifying the relationship between the ratio of CC bonds in the protective film on the mask and the amount of protective film loss due to etching.

[0022] Figure 11 This is a graph showing the results of comparing the line width roughness of a film finally formed when a bias RF signal is supplied to the substrate support portion in the second period and the line width roughness of a film finally formed when no bias RF signal is supplied to the substrate support portion.

[0023] Figure 12 The diagram shows the results of measuring the shape of a film finally formed when no bias RF signal is supplied to the substrate support portion during the third period and the shape of a film finally formed when a bias RF signal is supplied to the substrate support portion.

[0024] Figure 13 This is a graph showing the results of comparison of the ratio of CC bonds in the protective film on the mask when the temperature of the substrate support portion was set at 130°C and 155°C.

[0025] Figure 14 This is a diagram for explaining the configuration of a plasma processing apparatus when a voltage pulse signal is used as a bias signal.

[0026] Figure 15 1 is a diagram showing an example of supply of a generation source RF signal and a voltage pulse signal in each cycle.

[0027] Figure 16 This is a diagram for explaining the configuration of a plasma processing apparatus in the case where an upper DC signal is supplied to an upper electrode. DETAILED DESCRIPTION

[0028] Hereinafter, each embodiment of the present invention will be described.

[0029] In an exemplary embodiment, a plasma processing apparatus is provided, comprising: a chamber; a substrate support disposed in the chamber; a gas supply unit for supplying a process gas into the chamber; a first power supply for supplying a generation source RF signal to the chamber to generate plasma from the process gas in the chamber; a second power supply for supplying a bias signal to the substrate support unit; and a control unit, the control unit: performing a plasma process that repeatedly performs a cycle sequentially including a first period, a second period, a third period, and a fourth period; controlling the first power supply so that the generation source RF signal has a first power level in the first period, a second power level that is less than the first power level and greater than zero power level in the second period, a third power level that is less than the first power level and greater than zero power level in the third period, and a fourth power level that is less than the first power level and greater than zero power level in the fourth period; and controlling the second power supply so that the bias signal has a fifth power level that is greater than zero power level in the second period, and a sixth power level that is greater than the fifth power level in the fourth period.

[0030] In an exemplary embodiment, during the third period, the bias signal has a zero power level.

[0031] In an exemplary embodiment, during the first period, the bias signal has a zero power level.

[0032] In an exemplary embodiment, the cycle has a period in the range of 100 μs to 10,000 μs.

[0033] In an exemplary embodiment, the substrate support has a temperature in the range of 100° C. to 200° C. during plasma processing.

[0034] In an exemplary embodiment, the bias signal is an RF signal or a DC voltage pulse signal.

[0035] In an exemplary embodiment, the DC voltage pulse signal includes a sequence of voltage pulses having a voltage level of negative polarity.

[0036] In an exemplary embodiment, the plasma processing includes substrate processing of etching the silicon-containing film through the opening of the mask.

[0037] In an exemplary embodiment, the silicon-containing film is at least one selected from a silicon oxide film and a silicon nitride film.

[0038] In an exemplary embodiment, the mask is at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film.

[0039] In one exemplary embodiment, the process gas includes a gas containing carbon and fluorine.

[0040] In an exemplary embodiment, the chamber includes an upper electrode disposed above the substrate support portion, and the generated source RF signal is supplied to the upper electrode.

[0041] In an exemplary embodiment, a plasma processing method is provided, comprising: (a) providing a substrate onto a substrate support portion disposed in a chamber, the substrate having a silicon-containing film and a mask including an opening formed thereon; and (b) supplying a processing gas into the chamber to generate plasma, the processing gas including a gas containing carbon and fluorine, wherein the (b) step comprises: (b-1) supplying a generating source RF signal having a first power level to the chamber to deposit a protective film on a surface of the silicon-containing film and a surface of the mask, wherein the thickness of the protective film deposited on the surface of the mask is greater than the thickness of the protective film deposited on the surface of the silicon-containing film; and (b-2) (b-1) process, supplying a generating source RF signal having a second power level greater than the first power level and less than the zero power level to the chamber, and supplying a bias signal having a third power level greater than the zero power level to the substrate support portion to remove the protective film on the surface of the silicon-containing film and modify the protective film on the surface of the mask; (b-3) process, stopping supplying the bias signal to the substrate support portion; and (b-4) process, supplying a bias signal having a fourth power level greater than the third power level to the substrate support portion to etch the silicon-containing film, and repeating the cycle including the (b-1) process, the (b-2) process, the (b-3) process and the (b-4) process in sequence.

[0042] In an exemplary embodiment, in the steps (b-3) and (b-4), a generated source RF signal having a power level less than the first power level and greater than a zero power level is supplied to the chamber.

[0043] In one exemplary embodiment, in step (b-1), supply of the bias signal to the substrate support portion is stopped.

[0044] In an exemplary embodiment, the cycle has a period in the range of 100 μs to 10,000 μs.

[0045] In an exemplary embodiment, in step (b), the substrate support portion has a temperature in the range of 100°C to 200°C.

[0046] In an exemplary embodiment, the mask includes at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film.

[0047] In an exemplary embodiment, the chamber includes an upper electrode disposed above the substrate support portion, and the generated source RF signal is supplied to the upper electrode.

[0048] In an exemplary embodiment, the silicon-containing film is at least one selected from a silicon oxide film and a silicon nitride film.

[0049] The following describes various embodiments of the present invention in detail with reference to the accompanying drawings. Identical or identical elements in the various figures are denoted by the same reference numerals, and duplicate descriptions are omitted. Unless otherwise specified, positional relationships, such as up, down, left, and right, are described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual proportions, and actual proportions are not limited to the proportions shown in the drawings.

[0050] <An Example of a Plasma Processing System>

[0051] Figure 1 : is a diagram for illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber (also simply referred to as a "chamber") 10, a substrate support portion 11, and a plasma generating portion 12. The plasma processing chamber 10 has a plasma processing space. In addition, the plasma processing chamber 10 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 the gas supply portion 20 described later, and the gas exhaust port is connected to the exhaust system 40 described later. The substrate support portion 11 is arranged in the plasma processing space and has a substrate support surface for supporting a substrate. The chamber 10 may include the substrate support portion 11.

[0052] The plasma generating section 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP: Capacitively Coupled Plasma), inductively coupled plasma (ICP: Inductively Coupled Plasma), ECR plasma (Electron-Cyclotron-resonance plasma: Electron cyclotron resonance plasma), helicon wave excited plasma (HWP: Helicon Wave Plasma) or surface wave plasma (SWP: Surface Wave Plasma), etc. In addition, various types of plasma generating sections including AC (Alternating Current: Alternating Current) plasma generating sections and DC (Direct Current: Direct Current) plasma generating sections may be used. In one embodiment, the AC signal (AC electric power) used in the AC plasma generating section has a frequency in the range of 100kHz to 10GHz. Therefore, the AC signal includes an RF (Radio Frequency: High Frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100kHz to 150MHz.

[0053] The control unit 2 is capable of processing computer-executable commands that enable the plasma processing device 1 to perform the various processes described in the present invention. The control unit 2 is configured to control the various elements of the plasma processing device 1 to perform the various processes described herein. In one embodiment, a portion or all of the control unit 2 may be included in the plasma processing device 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 is configured to read a program from the storage unit 2a2 and perform various control actions by executing the read program. The program may be pre-stored in the storage unit 2a2 or acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and read and executed from the storage unit 2a2 by the processing unit 2a1. The medium may be various storage media that can be read 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 RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0054] Next, a configuration example of a capacitive coupling type plasma processing apparatus will be described as an example of the plasma processing apparatus 1 . Figure 2 This is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0055] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. In addition, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to be able to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet unit includes a shower head 13. The substrate support unit 11 is arranged in the plasma processing chamber 10. The shower head 13 is arranged above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the shell of the plasma processing chamber 10.

[0056] The substrate support portion 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 when viewed from above. The substrate W is arranged on the central region 111a of the main body 111, and the ring assembly 112 is arranged 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 referred to as a substrate supporting surface for supporting the substrate W, and the annular region 111b is also referred to as a ring supporting surface for supporting the ring assembly 112.

[0057] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is arranged on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b arranged in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also has an annular area 111b. In addition, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may have the annular area 111b. In this case, the ring assembly 112 may be arranged on the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component. Furthermore, at least one RF / DC electrode coupled to the RF power supply 31 and / or DC power supply 32 (described later) may be disposed within the ceramic component 1111a. In this case, the at least one RF / DC electrode can function as a lower electrode. When a bias RF signal and / or DC signal (described later) is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Alternatively, the conductive component of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes.

[0058] The ring assembly 112 includes one or more ring components. In one embodiment, the one or more ring components include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0059] In addition, the substrate support portion 11 may include a temperature regulating module for regulating at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature regulating module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as salt water or gas may flow in the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic component 1111a of the electrostatic chuck 1111. In addition, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to the gap between the back surface of the substrate W and the central area 111a.

[0060] The shower head 13 is configured to be able to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlet ports 13c. The processing gas supplied to the gas supply port 13a can be introduced into the plasma processing space 10s from the plurality of gas inlet ports 13c through the gas diffusion chamber 13b. In addition, the shower head 13 includes at least one upper electrode. In addition, the gas inlet portion may include, in addition to the shower head 13, one or more side gas injection portions (SGI: Side Gas Injector) installed in one or more openings formed on the side wall 10a.

[0061] 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 via a corresponding flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device for modulating or pulsing the flow of the at least one process gas.

[0062] The power supply system 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 lower electrode and / or at least one upper electrode. This enables plasma to be formed from at least one process gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a portion of the plasma generating unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential can be generated on the substrate W, thereby introducing ion components in the generated plasma into the substrate W.

[0063] In one embodiment, the RF power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a 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. In one embodiment, the first RF generator 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0064] The second RF generating unit 31b is coupled to at least one lower 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 generating source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the generating 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 generating unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In addition, in various embodiments, at least one of the generating source RF signal and the bias RF signal may be pulsed.

[0065] Furthermore, the power supply system 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. The first DC signal may be a bias signal that generates a bias potential for directing ions in the plasma toward the substrate support 11. In one embodiment, the second DC generating unit 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0066] In various embodiments, the first DC signal and the second DC signal can be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses can have rectangular, trapezoidal, triangular, or a combination thereof pulse waveforms. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and the at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute the voltage pulse generator. If the second DC generator 32b and the waveform generator constitute the voltage pulse generator, the voltage pulse generator is connected to the at least one upper electrode. The voltage pulses can have either positive or negative polarity. Furthermore, the sequence of voltage pulses can include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses within a cycle. Furthermore, the first DC generator 32a and the second DC generator 32b can be provided in addition to the RF power supply 31, or the first DC generator 32a can be provided in place of the second RF generator 31b.

[0067] The exhaust system 40 can be connected to the gas exhaust port 10e provided at the bottom of the plasma processing chamber 10, for example. The exhaust system 40 can include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s can be regulated by the pressure regulating valve. The vacuum pump can include a turbomolecular pump, a dry pump, or a combination thereof.

[0068] <First embodiment>

[0069] like Figure 3 As shown, in one embodiment, the plasma processing apparatus 1 may include a first RF power source 200 and a second RF power source 201 as the power supply system 30 . Figure 3 The plasma processing apparatus 1 shown is Figure 2 The first RF power supply 200 and the second RF power supply 201 are examples of the RF power supply 31 .

[0070] In one embodiment, the first RF power source 200 is electrically connected to an upper electrode, which is part of the chamber 10, and is configured to generate a source RF signal for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. The generated first RF signal is supplied to the upper electrode. By supplying the source RF signal to the upper electrode, plasma is formed from the process gas supplied into the chamber 10.

[0071] In one embodiment, the second RF power supply 201 is electrically connected to the lower electrode and is configured to generate a bias RF signal for bias generation. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. The generated bias RF signal is supplied to the lower electrode. By supplying the bias RF signal to the lower electrode, a bias potential is generated on the substrate W, enabling the ion components in the generated plasma to be introduced into the substrate W. The supply of the source RF signal by the first RF power supply 200 and the bias RF signal by the second RF power supply 201 are controlled by the control unit 2.

[0072] In one embodiment, Figure 4 As shown, the control unit 2 performs plasma processing, which repeats a cycle including a first period S1, a second period S2, a third period S3, and a fourth period S4. In one embodiment, each cycle has a period ranging from 100 μs to 10,000 μs. In one embodiment, the plasma processing of each substrate W is repeated multiple times.

[0073] In one embodiment, the first RF power source 200 supplies a generated RF signal (HF) to the upper electrode of the chamber 10 during each cycle. The generated RF signal has a first power level P1 during a first period S1 of each cycle, a second power level P2 during a second period S2 of each cycle, a third power level P3 during a third period S3 of each cycle, and a fourth power level P4 during a fourth period S4 of each cycle. The power level (W) is an example of a power level.

[0074] In one embodiment, the first electric power level P1 has an electric power level within a range of 100W to 500W. In one embodiment, the second electric power level P2 is less than the first electric power level P1 and greater than the zero electric power level (0W). In one embodiment, the second electric power level P2 has an electric power level within a range of 100W to 500W. In one embodiment, the third electric power level P3 is less than the first electric power level P1 and greater than the zero electric power level (0W). In one embodiment, the third electric power level P3 may be the same as the second electric power level P2 or may be smaller than the second electric power level P2. In one embodiment, the third electric power level P3 has an electric power level within a range of 50W to 300W. The fourth electric power level P4 is less than the first electric power level P1 and greater than the zero electric power level (0W). In one embodiment, the fourth electric power level P4 may be the same as the second electric power level P2 or may be smaller than the second electric power level P2. In one embodiment, the fourth electric power level P4 is the same as the third electric power level P3. In one embodiment, the fourth electric power level P4 has an electric power level within a range of 50W to 300W.

[0075] In one embodiment, the second RF power source 201 supplies a bias RF signal (LF) to the lower electrode of the substrate support 11 during each cycle. In one embodiment, the bias RF signal has a fifth power level P5 during the second period S2 of each cycle and a sixth power level P6 during the fourth period S4 of each cycle. The bias RF signal may have a zero power level (0 W) during the first period S1 and the third period S3.

[0076] In one embodiment, the fifth electric power level P5 is greater than the zero electric power level (0 W). In one embodiment, the fifth electric power level P5 has an electric power level within a range of 10 W to 200 W. In one embodiment, the sixth electric power level P6 is greater than the fifth electric power level P5. In one embodiment, the sixth electric power level P6 has an electric power level within a range of 100 W to 800 W.

[0077] In one embodiment, the second period S2, the third period S3, and the fourth period S4 may be longer than the first period S1. The fourth period S4 may be longer than the second period S2 and the third period S3.

[0078] <An Example of Plasma Treatment>

[0079] The plasma processing performed using the plasma processing apparatus 1 includes an etching process for etching a film on the substrate W using plasma. The etching process includes a process for etching a silicon-containing film through an opening portion of a mask on the substrate.

[0080] Figure 5 The figure shows an example of a film on a substrate W before etching. A silicon-containing film EF, serving as an etched film, is formed on a base film UF of the substrate W, and a mask M having a predetermined pattern (opening) is formed on the surface of the silicon-containing film ER. The silicon-containing film ER may be at least one selected from a silicon oxide film and a silicon nitride film. The silicon-containing film ER may be a single layer or a multilayer. The silicon-containing film ER may include a silicon oxide film ER1 and a silicon nitride film ER2. The silicon oxide film ER1 may be formed below the mask M and above the silicon nitride film ER2. The mask M may be at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film. The base film UF may be an oxide film. The base film UF may be a single layer or a multilayer.

[0081] In one embodiment, the plasma treatment is performed by the control unit 2. First, the temperature of the support surface of the substrate support unit 11 is set and maintained in the range of 100°C to 200°C. The temperature of the substrate supported on the support surface of the substrate support unit 11 can also be set and maintained in the range of 100°C to 200°C. The substrate W is transported into the chamber 10 by the transport arm and placed on the substrate support unit 11 by the lifter. Figure 3 The substrate is shown to be held by adsorption on the substrate support portion 11.

[0082] Next, the processing gas is supplied to the shower head 13 by the gas supply unit 20, and is supplied from the shower head 13 to the plasma processing space 10s. The processing gas supplied at this time contains a gas that generates active species required for etching the substrate W. The processing gas may include a CF-type gas containing carbon and fluorine. The CF-type gas may be at least one selected from a fluorocarbon gas and a hydrofluorocarbon gas. In one example, the fluorocarbon gas may be at least one selected from CF4 gas, C2F2 gas, C2F4 gas, C3F6 gas, C3F8 gas, C4F6 gas, C4F8 gas, and C5F8 gas. In one example, the hydrofluorocarbon gas may be at least one selected from CHF3 gas, CH2F2 gas, CH3F gas, C2HF5 gas, and a hydrofluorocarbon gas containing three or more Cs (C3H2F4 gas, C3H2F6 gas, C4H2F6 gas, etc.).

[0083] In one embodiment, a first RF power source 200 supplies a source RF signal to the upper electrode of the chamber 10. A second RF power source 201 supplies a bias RF signal to the lower electrode. At this point, the atmosphere within the plasma processing space 10s can be exhausted from the gas outlet 10e, and the pressure within the plasma processing space 10s is reduced to a predetermined level. Plasma is generated in the plasma processing space 10s, and the substrate W is etched.

[0084] In one embodiment, Figure 4 As shown, during a first period S1 of plasma processing, a first RF signal (HF) having a first power level P1 is supplied to the upper electrode (ON state). In one embodiment, the bias RF signal (LF) is at a zero power level (0 W), and the supply of the bias RF signal is stopped (OFF state).

[0085] Figure 6 This diagram illustrates an example of the state of films on a substrate during the first period S1, the second period S2, the third period S3, and the fourth period S4. In one embodiment, during the first period S1, ions and radicals generated from the CF-based gas included in the process gas are deposited on the surface of the mask M and the surface of the silicon-containing film EF (silicon oxide film ER1) on the substrate W, forming a protective film PF. The thickness of the protective film PF1 deposited on the surface of the mask MF is greater than the thickness of the protective film PF2 deposited on the surface of the silicon-containing film EF.

[0086] In one embodiment, during the second period S2 of the plasma treatment, as shown in FIG. Figure 4As shown, a generated source RF signal (HF) having a second power level P2 is supplied to the upper electrode (ON state), and a bias RF signal (LF) having a fifth power level P5 is supplied to the lower electrode (ON state). In one embodiment, the second power level P2 is less than the first power level P1.

[0087] In one embodiment, during the second period S2, as Figure 6 As shown, compared to the first period S1, the generation of ions and free radicals is suppressed, and ions are introduced to the substrate W side. As a result, the protective film PF2 formed on the surface of the silicon-containing film EF on the substrate W is removed, and the protective film PF1 formed on the surface of the mask M is modified. In one embodiment, the protective film PF1 on the surface of the mask M is modified by increasing the proportion of C-C bonds in the film. Furthermore, in one embodiment, the lower the second power level P2 and the higher the fifth power level P5, the more the removal of the silicon-containing film EF and the modification of the protective film PF are promoted. Furthermore, the higher the second power level P2, the more the formation of the protective film PF is promoted.

[0088] In one embodiment, during the third period S3 of the plasma treatment, as shown in FIG. Figure 4 As shown, a source RF signal (HF) having a third power level P3 is supplied to the upper electrode (ON state). In one embodiment, the bias RF signal (LF) is at a zero power level (0 W), and the supply of the bias RF signal is stopped (OFF state). In one embodiment, the third power level P3 is lower than the first power level P1.

[0089] In one embodiment, during the third period S3, as shown in FIG. Figure 6 As shown in FIG. 1 , the generation of ions and radicals is suppressed compared to the first period S1 , and the temperature of the ions is lowered.

[0090] In one embodiment, during the fourth period S4 of the plasma treatment, as shown in FIG. Figure 4 As shown, a generated source RF signal (HF) having a fourth power level P4 is supplied to the upper electrode (ON state). A bias RF signal (LF) having a sixth power level P6 is supplied to the lower electrode (ON state). In one embodiment, the fourth power level P4 is less than the first power level P1. In one embodiment, the sixth power level P6 is greater than the fifth power level P5.

[0091] In one embodiment, during the fourth period S4, as shown in FIG. Figure 6 As shown, ions are vertically introduced into the substrate W side, and the silicon-containing film EF is etched.

[0092] In one embodiment, the cycle from the first period S1 to the fourth period S4 is repeated a predetermined number of times, for example, Figure 7 As shown, the silicon-containing film ER is etched downward into a hole shape or a groove shape, and finally a hole or a groove is formed in the silicon oxide film ER1 and the silicon nitride film ER2 of the silicon-containing film ER.

[0093] According to this exemplary embodiment, in the plasma processing apparatus 1, the control unit 2 executes a plasma process that repeats a cycle sequentially including a first period S1, a second period S2, a third period S3, and a fourth period S4. The source RF signal (source RF power) is generated to have a first power level P1 during the first period S1, a second power level P2 during the second period S2, a third power level P3 during the third period S3, and a fourth power level P2 during the fourth period S4. The bias RF signal (bias RF power) is generated to have a fifth power level P5 during the second period S2 and a sixth power level P6 during the fourth period S4. During the second period S2, the protective film PF on the mask M is modified, thereby reducing the roughness of the film formed by the plasma process.

[0094] According to this exemplary embodiment, in the third period S3, the bias RF signal has a zero power level. As a result, the temperature of the ions in the plasma in the third period S3 decreases. Figure 8 According to the equation shown, the incident angle θ of ions onto the film on the substrate depends on the temperature Ti of the ions. Therefore, as the temperature Ti of the ions decreases, the incident angle θ decreases, and the perpendicularity of the ions introduced into the substrate W improves. Figure 8 In the formula, Vbias is the bias potential generated in the substrate supporting portion 11 .

[0095] According to this exemplary embodiment, during plasma processing, the substrate support 11 has a temperature within the range of 100°C to 200°C. This promotes modification of the protective film formed on the mask, and reduces the roughness of the film formed by plasma processing. The temperature of the substrate support 11 may be within the range of 130°C to 200°C, or may be within the range of 150°C to 200°C.

[0096] <Implementation Method>

[0097] The ratio (Ra) of CC bonds (carbon bonds) in the protective film on the mask when a bias RF signal (LF) having a fifth electric power level P5 is supplied to the substrate support portion 11 (ON: turned on) during the second period S2 of plasma treatment and the ratio (Ra) of CC bonds in the protective film on the mask when a bias RF signal (LF) is not supplied to the substrate support portion 11 (OFF: turned off) are compared. Figure 9is a graph showing the results of this comparison. Figure 9 As shown in FIG. 1 , the CC coupling ratio (Ra) increases when the bias RF signal is supplied (ON) compared to when the bias RF signal is not supplied (OFF). This confirms that the modification of the protective film is promoted by supplying the bias RF signal to the substrate support portion 11 during the second period S2.

[0098] The relationship between the ratio of CC bonds in the protective film on the mask (Ra) and the amount of the protective film lost by etching (La) was verified. Figure 10 is a graph showing the results of this verification. Figure 10 As shown in the figure, as the ratio of CC bonds (Ra) in the protective film on the mask increases, the amount of protective film loss (La) decreases. This confirms that the higher the ratio of CC bonds (Ra) in the protective film, the higher the etching resistance of the protective film. Consequently, by increasing the ratio of CC bonds (Ra) in the protective film, the removal of the mask and the etched film caused by etching, i.e., the roughness of the film, can be reduced. Furthermore, the etching selectivity can be improved.

[0099] The line width roughness (LWR) of the film finally formed during the second plasma treatment period S2 was compared between the case where a bias RF signal (LH) having a fifth power level P5 was supplied to the substrate support portion 11 (ON) and the case where no bias RF signal (LH) was supplied to the substrate support portion 11 (OFF). The line width roughness (LWR) is represented by, for example, a line width deviation of 3σ (σ: standard deviation). Figure 11 is a graph showing the results of this comparison. Figure 11 As shown in FIG. 1 , the line width roughness (LWR) of the film is reduced when the bias RF signal is supplied (ON) compared to when the bias RF signal is not supplied (OFF). This confirms that the roughness of the film is reduced by supplying the bias RF signal to the substrate support portion 11 during the second period S2.

[0100] During the third period S3 of the plasma treatment, the shape of the film finally formed when the bias RF signal (LH) is not supplied to the substrate support part 11 (OFF: closed) and the shape of the film finally formed when the bias RF signal (LH) is supplied to the substrate support part 11 (ON: opened) are measured. Figure 12 Indicates the result of the measurement. Figure 12As shown, when the bias RF signal is not supplied to the substrate support unit 11 (OFF) during the third period S3, the angle α1 of the film side wall is larger than the angle α2 of the film side wall when the bias RF signal (LH) is supplied to the substrate support unit 11 (ON) during the third period S3. It can be confirmed that the verticality of the film shape is improved by not supplying the bias RF signal to the substrate support unit 11 during the third period S3.

[0101] The ratio of CC bonds in the protective film on the mask when the temperature of the substrate support portion 11 during the plasma treatment was set to 130° C. and 155° C. was measured and compared. Figure 13 is a graph showing the results of this comparison. Figure 13 As shown in FIG. 1 , when the temperature of the substrate support portion 11 is increased, the ratio of CC bonds in the protective film increases.

[0102] In the above embodiment, if Figure 14 As shown, the plasma processing apparatus 1 may include a DC power supply 300 instead of the second RF power supply 201 as the second power supply. That is, as a bias signal, a voltage pulse signal may be supplied to the substrate support portion 11 instead of the bias RF signal (LF). The other structures of the plasma processing apparatus 1 may be the same as those in the above embodiment. The DC power supply 300 is Figure 2 An example of the DC power supply 32 is shown.

[0103] In one embodiment, the DC power supply 300 is configured to be electrically connected to the lower electrode of the substrate support portion 11 to generate a DC voltage pulse signal. The generated voltage pulse signal is applied to the lower electrode. Figure 15 As shown, in one embodiment, a voltage pulse signal (DC) functions as a bias signal (bias DC signal). The voltage pulse signal may have the following sequence: a first voltage level V1 during the second period S2 of each cycle in the plasma process, and a second voltage level V2 during the fourth period S4 of each cycle. The voltage pulse signal may have a zero voltage level during the first period S1 and the third period S3 of each cycle. The voltage level (V) is an example of a power level.

[0104] In one embodiment, the sequence of voltage pulses has a pulse frequency in the range of 300kHz to 600kHz. The absolute value of the second voltage level V2 may be greater than the absolute value of the first voltage level V1. In one embodiment, the first voltage level V1 and the second voltage level V2 may have a negative polarity. The supply of the source RF signal (HF) may be generated at a level of electrical power similar to that of the first voltage level V1. Figure 4 The same embodiment as above is shown.

[0105] In the above embodiments, Figure 16As shown, the plasma processing apparatus 1 may further include an upper DC power supply 500 in addition to the first RF power supply 200 and the second RF power supply 201 or the DC power supply 300. In one embodiment, the DC power supply 500 is Figure 2 An example of the DC power supply 32 is shown.

[0106] In one embodiment, the upper DC power supply 500 is coupled to the upper electrode of the chamber 10 and is configured to generate a direct current upper DC signal. The generated upper DC signal is supplied to the upper electrode of the chamber 10. The upper DC signal may have a negative polarity and a negative voltage level. In one embodiment, the upper DC signal may be pulsed. The pulse signal of the upper DC signal may have a rectangular voltage pulse waveform. The upper DC signal may be supplied to the upper electrode during the first cycle S1 and the second cycle S2 of the plasma process. The upper DC signal may be supplied to the upper electrode during the third cycle S3 and the fourth cycle S4 of the plasma process.

[0107] By supplying an upper DC signal to the upper electrode, in one embodiment, the self-bias voltage of the upper electrode can be increased, thereby enhancing the sputtering effect on the surface of the upper electrode. In one embodiment, by supplying an upper DC signal to the upper electrode, electrons generated at the upper electrode can be irradiated onto the substrate W. In one embodiment, the plasma potential can be controlled. In one embodiment, by supplying an upper DC signal to the upper electrode, the electron density of the plasma can be increased.

[0108] For example, in the above embodiment, a capacitively coupled plasma device is used as an example for description, but the present invention is not limited to this and can also be applied to other plasma devices. For example, an inductively coupled plasma device can be used instead of a capacitively coupled plasma device. In this case, the inductively coupled plasma device includes an antenna and a lower electrode. The lower electrode is arranged in the substrate support portion, and the antenna is arranged in the upper part or above the chamber. In addition, in one embodiment, the first RF power supply 200 is electrically connected to the antenna, and the second RF power supply 201 is electrically connected to the lower electrode. In addition, a DC power supply 300 can also be used instead of the second RF power supply 201. In this way, the first RF power supply 200 is electrically connected to the upper electrode of the capacitively coupled plasma device or the antenna of the inductively coupled plasma device. In other words, the first RF power supply 200 is coupled to the plasma processing chamber 10.

[0109] The embodiments of the present invention also include the following aspects.

[0110] (Note 1)

[0111] A plasma processing apparatus comprising:

[0112] chamber;

[0113] a substrate support portion disposed in the chamber;

[0114] a gas supply unit for supplying a processing gas into the chamber;

[0115] a first power supply for supplying a generating source RF signal to the chamber to generate plasma from the process gas in the chamber;

[0116] a second power supply for supplying a bias signal to the substrate support portion; and

[0117] Control Department,

[0118] The above-mentioned control unit:

[0119] performing a plasma treatment that repeats a cycle sequentially including a first period, a second period, a third period, and a fourth period;

[0120] controlling the first power supply so that the generated source RF signal has a first power level during the first period, has a second power level that is lower than the first power level and greater than zero power level during the second period, has a third power level that is lower than the first power level and greater than zero power level during the third period, and has a fourth power level that is lower than the first power level and greater than zero power level during the fourth period;

[0121] The second power supply is controlled so that the bias signal has a fifth power level greater than a zero power level during the second period and has a sixth power level greater than the fifth power level during the fourth period.

[0122] (Note 2)

[0123] The plasma processing apparatus according to Supplementary Note 1, wherein:

[0124] During the third period, the bias signal has a zero power level.

[0125] (Note 3)

[0126] The plasma processing apparatus according to Supplementary Note 1 or 2, wherein:

[0127] During the first period, the bias signal has a zero power level.

[0128] (Note 4)

[0129] The plasma processing apparatus according to any one of Supplementary Notes 1 to 3, wherein:

[0130] The above-mentioned cycle has a period within a range of 100 μs to 10,000 μs.

[0131] (Note 5)

[0132] The plasma processing apparatus according to any one of Supplementary Notes 1 to 4, wherein:

[0133] In the plasma processing, the substrate support portion has a temperature in a range of 100°C to 200°C.

[0134] (Note 6)

[0135] The plasma processing apparatus according to any one of Supplementary Notes 1 to 5, wherein:

[0136] The bias signal is an RF signal or a DC voltage pulse signal.

[0137] (Note 7)

[0138] The plasma processing apparatus according to Supplementary Note 6, wherein:

[0139] The DC voltage pulse signal includes a sequence of voltage pulses having a voltage level of negative polarity.

[0140] (Note 8)

[0141] The plasma processing apparatus according to any one of Supplementary Notes 1 to 7, wherein:

[0142] The plasma treatment includes substrate processing for etching the silicon-containing film through the openings of the mask.

[0143] (Note 9)

[0144] The plasma processing apparatus according to Supplementary Note 8, wherein:

[0145] The silicon-containing film is at least one selected from a silicon oxide film and a silicon nitride film.

[0146] (Note 10)

[0147] The plasma processing apparatus according to Supplementary Note 8 or 9, wherein:

[0148] The mask is at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film.

[0149] (Note 11)

[0150] The plasma processing apparatus according to any one of Supplementary Notes 1 to 10, wherein

[0151] The processing gas includes a gas containing carbon and fluorine.

[0152] (Note 12)

[0153] The plasma processing apparatus according to any one of Supplementary Notes 1 to 11, wherein:

[0154] The chamber includes an upper electrode disposed above the substrate support portion.

[0155] The generation source RF signal is supplied to the upper electrode.

[0156] (Note 13)

[0157] A plasma treatment method comprising:

[0158] (a) providing a substrate having a silicon-containing film and a mask including an opening formed thereon onto a substrate support portion disposed in a chamber; and

[0159] (b) supplying a processing gas into the chamber to generate plasma, wherein the processing gas includes a gas containing carbon and fluorine,

[0160] The above step (b) comprises:

[0161] (b-1) supplying a generator RF signal having a first power level to the chamber to deposit a protective film on a surface of the silicon-containing film and a surface of the mask, wherein the protective film deposited on the surface of the mask has a greater thickness than the protective film deposited on the surface of the silicon-containing film;

[0162] (b-2) supplying the generating source RF signal having a second power level smaller than the first power level and larger than a zero power level to the chamber, and supplying a bias signal having a third power level larger than a zero power level to the substrate support portion, thereby removing the protective film on the surface of the silicon-containing film and modifying the protective film on the surface of the mask;

[0163] (b-3) step of stopping supplying the bias signal to the substrate support portion; and

[0164] (b-4) supplying the bias signal having a fourth power level greater than the third power level to the substrate support portion to etch the silicon-containing film;

[0165] A cycle including the above-mentioned step (b-1), the above-mentioned step (b-2), the above-mentioned step (b-3), and the above-mentioned step (b-4) is repeated in this order.

[0166] (Note 14)

[0167] The plasma treatment method according to Supplementary Note 13, wherein:

[0168] In the steps (b-3) and (b-4), the generation source RF signal having a power level lower than the first power level and higher than a zero power level is supplied to the chamber.

[0169] (Note 15)

[0170] The plasma treatment method according to Supplementary Note 13 or 14, wherein

[0171] In the step (b-1), supply of the bias signal to the substrate support portion is stopped.

[0172] (Note 16)

[0173] The plasma treatment method according to any one of Supplementary Notes 13 to 15, wherein

[0174] The above-mentioned cycle has a period within a range of 100 μs to 10,000 μs.

[0175] (Note 17)

[0176] The plasma treatment method according to any one of Supplementary Notes 13 to 16, wherein

[0177] In the step (b), the substrate support portion has a temperature in the range of 100°C to 200°C.

[0178] (Note 18)

[0179] The plasma treatment method according to any one of Supplementary Notes 13 to 17, wherein

[0180] The mask includes at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film.

[0181] (Note 19)

[0182] The plasma treatment method according to any one of Supplementary Notes 13 to 18, wherein

[0183] The chamber includes an upper electrode disposed above the substrate support portion.

[0184] The generation source RF signal is supplied to the upper electrode.

[0185] (Note 20)

[0186] The plasma treatment method according to any one of Supplementary Notes 13 to 19, wherein

[0187] The silicon-containing film is at least one selected from a silicon oxide film and a silicon nitride film.

[0188] The above embodiments are described for illustration and are not intended to limit the scope of the present invention. The above embodiments can be modified in various ways without departing from the scope and gist of the present invention. For example, a portion of the components in a certain embodiment can be added to other embodiments. In addition, a portion of the components in a certain embodiment can be replaced with corresponding components in other embodiments.

[0189] Description of Reference Numerals

[0190] 1... plasma processing apparatus, 2... control unit, 10... plasma processing chamber, 10s... plasma processing space, 11... substrate support unit, 30... power supply system, 200... first RF power supply, 201... second RF power supply.

Claims

1. A plasma processing device, characterized in that include: chamber; a substrate support portion disposed in the chamber; a gas supply unit for supplying a processing gas into the chamber; a first power supply for supplying a source RF signal to the chamber to generate plasma from the process gas within the chamber; a second power supply for supplying a bias signal to the substrate support portion; and Control Department, The control unit: performing a plasma treatment that repeats a cycle sequentially including a first period, a second period, a third period, and a fourth period; controlling the first power source so that the generated source RF signal has a first power level during the first period, a second power level that is less than the first power level and greater than zero power level during the second period, a third power level that is less than the first power level and greater than zero power level during the third period, and a fourth power level that is less than the first power level and greater than zero power level during the fourth period; The second power supply is controlled so that the bias signal has a fifth power level greater than a zero power level during the second period and has a sixth power level greater than the fifth power level during the fourth period.

2. The plasma processing apparatus according to claim 1, wherein: During the third period, the bias signal has a zero power level.

3. The plasma processing apparatus according to claim 1, wherein: During the first period, the bias signal has a zero power level.

4. The plasma processing apparatus according to claim 1, wherein: The cycle has a period in the range of 100 μs to 10,000 μs.

5. The plasma processing apparatus according to claim 1, wherein: In the plasma processing, the substrate support has a temperature in a range of 100°C to 200°C.

6. The plasma processing apparatus according to claim 1, wherein: The bias signal is an RF signal or a DC voltage pulse signal.

7. The plasma processing apparatus according to claim 6, wherein: The DC voltage pulse signal includes a sequence of voltage pulses having a voltage level of negative polarity.

8. The plasma processing apparatus according to claim 1, wherein: The plasma treatment includes substrate processing for etching the silicon-containing film through the opening of the mask.

9. The plasma processing apparatus according to claim 8, wherein: The silicon-containing film is at least one selected from a silicon oxide film and a silicon nitride film.

10. The plasma processing apparatus according to claim 8, wherein: The mask is at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film.

11. The plasma processing apparatus according to claim 1, wherein: The process gas includes a gas containing carbon and fluorine.

12. The plasma processing apparatus according to claim 1, wherein: The chamber includes an upper electrode disposed above the substrate support portion. The generation source RF signal is supplied to the upper electrode.

13. A plasma treatment method, characterized in that: include: (a) providing a substrate having a silicon-containing film and a mask including an opening formed thereon onto a substrate support portion disposed in a chamber; and (b) supplying a processing gas into the chamber to generate plasma, wherein the processing gas includes a gas containing carbon and fluorine, The (b) step comprises: (b-1) supplying a generator RF signal having a first power level to the chamber to deposit a protective film on a surface of the silicon-containing film and a surface of the mask, wherein the protective film deposited on the surface of the mask has a thickness greater than that of the protective film deposited on the surface of the silicon-containing film; (b-2) supplying the generating source RF signal having a second power level smaller than the first power level and larger than a zero power level to the chamber, and supplying a bias signal having a third power level larger than a zero power level to the substrate support portion, so as to remove the protective film on the surface of the silicon-containing film and modify the protective film on the surface of the mask; (b-3) step of stopping supply of the bias signal to the substrate support portion; and (b-4) supplying the bias signal having a fourth power level greater than the third power level to the substrate support portion to etch the silicon-containing film, A cycle including the step (b-1), the step (b-2), the step (b-3), and the step (b-4) in this order is repeated.

14. The plasma processing method according to claim 13, wherein: In the steps (b-3) and (b-4), the generation source RF signal having a power level lower than the first power level and higher than a zero power level is supplied to the chamber.

15. The plasma processing method according to claim 13, wherein: In the step (b-1), supply of the bias signal to the substrate support portion is stopped.

16. The plasma processing method according to claim 13, wherein: The cycle has a period in the range of 100 μs to 10,000 μs.

17. The plasma processing method according to claim 13, wherein: In the step (b), the substrate support portion has a temperature in the range of 100°C to 200°C.

18. The plasma processing method according to claim 13, wherein: The mask includes at least one selected from a silicon film, a silicon nitride film, a silicon oxide film, a metal-containing film, and an organic film.

19. The plasma processing method according to claim 13, wherein: The chamber includes an upper electrode disposed above the substrate support portion. The generation source RF signal is supplied to the upper electrode.

20. The plasma processing method according to claim 13, wherein: The silicon-containing film is at least one selected from a silicon oxide film and a silicon nitride film.

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