Plasma processing method and plasma processing apparatus

Abstract

Provided is a technique for appropriately forming a recess in an etching film. A plasma processing method according to the present disclosure is a plasma processing method performed in a plasma processing apparatus provided with a chamber and a substrate support portion provided in the chamber, the plasma processing method including: (a) a preparation step, preparing, on the substrate support part, a substrate having a silicon-containing film, which is an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern having an opening width of 30 nm or less; and a step (b) in which plasma is generated in the chamber and the silicon-containing film is etched through the mask to form a recess in the silicon-containing film, the step (b) including: a step (b-1) in which a processing gas containing hydrogen fluoride is supplied into the chamber; a step (b-2) for generating plasma from the processing gas in the chamber; and a step (b-3) of supplying a bias signal to the substrate support unit, the bias signal being a bias RF signal having a power effective value of less than 2 kW, or a bias DC signal including a sequence of DC pulses of negative polarity having a voltage effective value of less than 2 kV.

Description

Technical Field

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

[0002] In the manufacture of electronic devices, plasma etching of a silicon-containing film of a substrate is performed. For example, Patent Document 1 discloses a method of etching a dielectric film by plasma etching.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-39309 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides a technology for appropriately forming a recessed portion in an etching film.

[0008] Solutions for solving problems

[0009] In an exemplary embodiment of the present disclosure, there is provided a plasma processing method performed in a plasma processing apparatus, the plasma processing apparatus having a chamber and a substrate support portion disposed in the chamber, the plasma processing method comprising the following steps: step (a), which is a preparation step, preparing a substrate in the substrate support portion, the substrate having a silicon-containing film and a mask on the silicon-containing film, the mask comprising an opening pattern; and step (b), generating plasma in the chamber, and etching the silicon-containing film through the mask to form a recess in the silicon-containing film, wherein the step (b) comprises the following steps: step (b-1), supplying a processing gas containing hydrogen fluoride into the chamber; step (b-2), generating plasma from the processing gas in the chamber; and step (b-3), supplying a bias signal to the substrate support portion, the effective value of the power of the bias signal being less than 2 kW.

[0010] Effects of the Invention

[0011] According to the exemplary embodiment of the present disclosure, it is possible to appropriately form a recessed portion in an etching film. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0013] Figure 2 It is a diagram for explaining a structural example of a plasma processing apparatus.

[0014] Figure 3 This is a flowchart showing an example of the present processing method.

[0015] Figure 4A 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0016] Figure 4B 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0017] Figure 4C 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0018] Figure 4D 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0019] Figure 4E 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0020] Figure 5 This is a flowchart showing an example of step ST1.

[0021] Fig. 6A 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0022] Figure 6B 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0023] Figure 6C 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0024] Fig.6D 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0025] Figure 7 This is a flowchart showing an example of step ST1.

[0026] Fig. 8A 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0027] Figure 8B 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0028] Figure 8C 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0029] Fig.8D 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0030] Fig. 8E 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0031] Fig. 9 This is a flowchart showing an example of step ST1.

[0032] Fig. 10A 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0033] Fig. 10B 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0034] Fig. 10C 1 is a diagram showing an example of a cross-sectional structure of a substrate W.

[0035] Fig.11 This is a flowchart showing an example of step ST23.

[0036] Fig. 12A 1 is a diagram showing an example of a cross-sectional structure of the substrate W in step ST23 .

[0037] Fig. 12B 1 is a diagram showing an example of a cross-sectional structure of the substrate W in step ST23 . DETAILED DESCRIPTION

[0038] Hereinafter, each embodiment of the present disclosure will be described.

[0039] In an exemplary embodiment, a plasma processing method performed in a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber, and the plasma processing method includes the following steps: step (a) is a preparation step, in which a substrate is prepared on the substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern with an opening width of 30 nm or less; and step (b) generates plasma in the chamber, and etches the silicon-containing film through the mask to form a recess in the silicon-containing film, wherein step (b) includes the following steps: step (b-1) supplies a processing gas including hydrogen fluoride into the chamber; step (b-2) generates plasma from the processing gas in the chamber; and step (b-3) supplies a bias signal to the substrate support portion, the bias signal being a bias RF (radio frequency) signal having an effective value of power less than 2 kW, or a bias DC signal including a sequence of negative polarity DC pulses having an effective value of voltage less than 2 kV.

[0040] In an exemplary embodiment, a substrate supporting surface of a substrate supporting portion for supporting a substrate includes a plurality of zones, step (a) includes a step of setting the temperature of the substrate supporting portion in units of zones, and in step (b), the silicon-containing film is etched while the temperature of the substrate supporting portion is set in units of zones.

[0041] In an exemplary embodiment, the substrate support has a temperature control module including one or more heaters for adjusting the temperature of the substrate, and step (b) is performed with the temperature of the substrate support set to 80° C. or less by the temperature control module.

[0042] In an exemplary embodiment, the process gas further includes at least one gas selected from the group consisting of a carbon-containing gas, a phosphorus-containing gas, a metal-containing gas, a boron-containing gas, an oxygen-containing gas, and a halogen-containing gas.

[0043] In one exemplary embodiment, the process gas includes a phosphorus-containing gas.

[0044] In an exemplary embodiment, the process gas includes at least one inert gas selected from the group consisting of a rare gas and a nitrogen gas.

[0045] In an exemplary embodiment, the ratio of the flow rate of the hydrogen fluoride gas and the inert gas to the total flow rate of the process gas is 50 volume % or more.

[0046] In an exemplary embodiment, the ratio of the flow rate of the inert gas to the flow rate of the hydrogen fluoride gas is 0.1 or more and 200 or less.

[0047] In an exemplary embodiment, a plasma processing apparatus comprises: a first gas injection portion, which is arranged on the upper surface of a chamber in a manner facing a substrate support portion; and a second gas injection portion, which is arranged on the side of the chamber, and the processing gas includes at least one first gas that does not contain carbon and at least one second gas that contains carbon, and at least one of the first gases is supplied from the first gas injection portion, and at least one of the second gases is supplied from the second gas injection portion.

[0048] In an exemplary embodiment, a plasma processing device comprises: a first gas injection portion, which is arranged on the upper surface of the chamber in the chamber; and a second gas injection portion, which is arranged on the side of the chamber in the chamber, the processing gas includes at least one carbon-containing gas, and the at least one carbon-containing gas is supplied into the chamber from the first gas injection portion and the second gas injection portion, and the flow rate of the at least one carbon-containing gas supplied into the chamber from the second gas injection portion is greater than the flow rate of the at least one carbon-containing gas supplied into the chamber from the first gas injection portion.

[0049] In an exemplary embodiment, in step (b), the pressure in the chamber is set to 50 mTorr or less.

[0050] In an exemplary embodiment, the mask includes a resist film.

[0051] In an exemplary embodiment, the mask includes an EUV (extreme ultraviolet lithography) resist film.

[0052] In an exemplary embodiment, the resist film includes a metal-containing resist.

[0053] In an exemplary embodiment, the thickness of the silicon-containing film is 40 nm or less.

[0054] In an exemplary embodiment, the aspect ratio of the recessed portion formed in the silicon-containing film is 5 or less.

[0055] In an exemplary embodiment, step (a) includes the following steps: step (a-1), preparing a substrate including a silicon-containing film, an anti-reflection film on the silicon-containing film, and a mask on the anti-reflection film; and step (a-2), using plasma generated from a first processing gas containing oxygen to remove a portion of the anti-reflection film exposed from the opening pattern and a portion of the mask.

[0056] In an exemplary embodiment, the following steps are included: step (a-3), after step (a-2), using a second processing gas to form a deposit of at least one selected from the group consisting of carbon, silicon and metal in a first region and a second region of the mask, wherein the first region includes the upper surface of the mask and the second region includes the side of the mask, and the side defines an opening pattern; and step (a-4), using plasma generated from a third processing gas containing oxygen to remove at least a portion of the deposit on the second region and a portion of the anti-reflection film exposed from the opening pattern.

[0057] In an exemplary embodiment, step (a) includes the following steps: step (a-1), preparing a substrate including a silicon-containing film, an anti-reflection film on the silicon-containing film, and a mask on the anti-reflection film; step (a-3), after step (a-1), using a second processing gas to form a deposit of at least one selected from the group consisting of carbon, silicon, and metal in a first region and a second region of the mask, wherein the first region includes an upper surface of the mask, the second region includes a side surface of the mask, and the side surface defines an opening pattern; and step (a-4), using a third processing gas to remove at least a portion of the deposit on the second region and a portion of the anti-reflection film exposed from the opening pattern.

[0058] In an exemplary embodiment, a plasma processing method performed in a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber, and the plasma processing method includes the following steps: step (a) is a preparation step, in which a substrate is prepared on the substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon and a mask on the silicon-containing film, the mask including an opening pattern; and step (b) generates plasma in the chamber, and etches the silicon-containing film through the mask to form a recess in the silicon-containing film, wherein in step (a), the width of the opening included in the opening pattern is 30 nm or less, and step (b) includes the following steps: step (b-1) supplies a processing gas containing at least hydrogen and fluorine into the chamber; step (b-2) generates a plasma containing a hydrogen fluoride species from the processing gas in the chamber; and step (b-3) supplies a bias signal to the substrate support portion, the bias signal being a bias RF signal having an effective value of 2 kW of power, or a bias DC signal including a sequence of negative polarity DC pulses having an effective value of less than 2 kV of voltage.

[0059] In one exemplary embodiment, a plasma processing method performed in a plasma processing apparatus is provided. A plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber, and a plasma processing method includes the following steps: step (a), preparing a substrate, the substrate including a first silicon-containing film, a carbon-containing film on the first silicon-containing film, a second silicon-containing film on the carbon-containing film, and a resist film on the second silicon-containing film, wherein the resist film includes an opening pattern having an opening width of 30 nm or less; step (b), etching the second silicon-containing film through the resist film to form a first recess in the second silicon-containing film; step (c), etching the carbon-containing film through the first recess to form a second recess in the carbon-containing film; and step (d), etching the first silicon-containing film through the second recess, wherein in steps (b), (c), and (d), a bias signal having an effective value of less than 2 kW is supplied to the substrate support portion, and step (b) includes the following steps: step (b-1), supplying a processing gas containing at least hydrogen and fluorine; and step (b-2), generating a plasma containing a hydrogen fluoride species from the processing gas.

[0060] In an exemplary embodiment, the substrate further includes a base film under the first silicon-containing film, and the step (d) includes the following steps: a step (d-1) of etching the first silicon-containing film using plasma generated from a fourth processing gas containing fluorine to form a third recess in the first silicon-containing film, wherein an opening size of the third recess on the carbon-containing film side is larger than an opening size on the base film side; and a step (d-2) of enlarging the opening size of the third recess on the base film side using plasma generated from a fifth processing gas containing hydrogen fluoride gas and a carbon-containing gas.

[0061] In an exemplary embodiment, the fourth process gas includes at least one of a hydrogen fluoride gas and a fluorocarbon gas, and the carbon-containing gas includes a hydrofluorocarbon gas having a carbon number of 3 or more.

[0062] In an exemplary embodiment, plasma is continuously generated during two or more consecutive steps among the step (b), the step (c), and the step (d).

[0063] In an exemplary embodiment, the plasma processing apparatus is an inductively coupled plasma processing apparatus, and step (a), step (b), step (c), and step (d) are performed in the same chamber.

[0064] In an exemplary embodiment, a plasma processing apparatus is provided, the plasma processing apparatus comprising a chamber, a gas supply unit, a plasma generating unit, a substrate supporting unit disposed in the chamber, and a control unit. In the plasma processing apparatus, the control unit performs the following control: control (a) to prepare a substrate on the substrate supporting unit, the substrate comprising a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask comprising an opening pattern having an opening width of 30 nm or less; and control (b) to generate plasma in the chamber and to etch the silicon-containing film through the mask to form a recess in the silicon-containing film, wherein in control (b), the control unit performs the following control: control (b-1) to supply a processing gas containing hydrogen fluoride into the chamber; control (b-2) to generate plasma from the processing gas in the chamber; and control (b-3) to supply a bias signal to the substrate supporting unit, the bias signal being a bias RF signal having an effective value of power less than 2 kW, or a bias DC signal including a sequence of negative polarity DC pulses having an effective value of voltage less than 2 kV.

[0065] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same or identical elements are marked with the same symbols in each of the drawings, and repeated descriptions are omitted. The positional relationships such as up, down, left, and right are described based on the positional relationships shown in the drawings, unless otherwise specified. The dimensional ratios in the drawings do not represent the actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0066] <An example of a plasma processing system>

[0067] 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 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 supporting surface for supporting a substrate.

[0068] The plasma generating unit 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 a capacitively coupled plasma (CCP; Capacitively Coupled Plasma), an inductively coupled plasma (ICP; Inductively Coupled Plasma), an ECR plasma (Electron-Cyclotron-resonance plasma: electron cyclotron resonance plasma), a helicon wave excited plasma (HWP: Helicon Wave Plasma) or a surface wave plasma (SWP: Surface Wave Plasma), etc. In addition, various types of plasma generating units including an AC (Alternating Current: alternating current) plasma generating unit and a DC (Direct Current: direct current) plasma generating unit may also be used. In one embodiment, the AC signal (AC power) used by the AC plasma generating unit has a frequency in the range of 100kHz to 10GHz. Therefore, the AC signal includes an RF (Radio Frequency: radio frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100kHz to 150MHz.

[0069] <An Example of Plasma Processing Apparatus>

[0070] Figure 21 is a diagram for explaining a structural example of a plasma processing system. The plasma processing system includes an inductively coupled plasma processing device 1 and a control unit 2. The inductively coupled plasma processing device 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. In addition, the plasma processing device 1 includes a substrate support unit 11, a gas introduction unit, and an antenna 14. The substrate support unit 11 is arranged in the plasma processing chamber 10. The antenna 14 is arranged 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, the side wall 102 of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s, and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded.

[0071] The substrate support portion 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central area 111a for supporting a substrate W, and an annular area 111b for supporting the ring assembly 112. A wafer is an example of a substrate. The annular area 111b of the main body 111 surrounds the central area 111a of the main body 111 when viewed from above. The substrate W is arranged on the central area 111a of the main body 111, and the ring assembly 112 is arranged on the annular area 111b of the main body 111 in a manner that surrounds the substrate W on the central area 111a of the main body 111. Therefore, the central area 111a is also referred to as a substrate supporting surface for supporting the substrate W, and the annular area 111b is also referred to as a ring supporting surface for supporting the ring assembly 112.

[0072] In one embodiment, the main body 111 includes a base 1110 and an electrostatic holding disk (holding disk: chuck) 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can function as a bias electrode. The electrostatic holding disk 1111 is arranged on the base 1110. The electrostatic holding disk 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 holding disk 1111, such as an annular electrostatic holding disk or an annular insulating component, may have an annular area 111b. In this case, the ring assembly 112 may be arranged on the annular electrostatic holding disk or the annular insulating component, or on both the electrostatic holding disk 1111 and the annular insulating component. In addition, at least one RF / DC electrode coupled to the RF (Radio Frequency) power supply 31 and / or the DC (Direct Current) power supply 32 described later may be arranged in the ceramic component 1111a. In this case, at least one RF / DC electrode functions as a bias electrode. In addition, the conductive component of the base 1110 and at least one RF / DC electrode may also function as a plurality of bias electrodes. In addition, the electrostatic electrode 1111b may function as a bias electrode. Thus, the substrate support portion 11 includes at least one bias electrode.

[0073] The ring assembly 112 includes one or more ring-shaped members. In one embodiment, the one or more ring-shaped members 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.

[0074] In addition, the substrate support portion 11 may include a temperature control module configured to adjust at least one of the electrostatic holding disk 1111, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path 1110a. In one embodiment, a flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic component 1111a of the electrostatic holding disk 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 side of the wafer W and the central area 111a.

[0075] The gas introduction part is configured to introduce at least one processing gas from the gas supply part 20 into the plasma processing space 10s. In one embodiment, the gas introduction part includes a central gas injection part (CGI: Center Gas Injector) 13. The central gas injection part 131 is arranged above the substrate support part 11 and installed in the central opening part formed in the dielectric window 101. The central gas injection part 131 has at least one gas supply port 131a, at least one gas flow path 131b and at least one gas introduction port 131c. The processing gas supplied to the gas supply port 131a passes through the gas flow path 131b and is introduced into the plasma processing space 10s from the gas introduction port 131c. In addition, the gas introduction part may include one or more side gas injection parts (SGI: Side Gas Injector) additionally or alternatively to the central gas injection part 131, and the one or more side gas injection parts are installed in one or more openings formed in the side wall 102.

[0076] The gas inlet portion may include a peripheral gas injection portion 52 as an example of a side gas injection portion. The peripheral gas injection portion 52 includes a plurality of peripheral injection ports 52i. The plurality of peripheral injection ports 52i mainly supply gas toward the edge of the substrate W. The plurality of peripheral injection ports 52i open toward the edge of the substrate W or the edge of the central region 111a supporting the substrate W. The plurality of peripheral injection ports 52i may be arranged at a height position equal to that of the gas inlet port 131c. In addition, the plurality of peripheral injection ports 52i may be arranged along the circumference of the substrate support portion 11 below the gas inlet port 131c and above the substrate support portion 11. That is, the plurality of peripheral injection ports 52i are arranged in a ring shape with the axis of the gas flow path 131b as the center in a region (plasma diffusion region) where the electron temperature is lower than the electron temperature directly below the dielectric window 101.

[0077] 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 the respective gas sources 21 to the gas introduction unit via the respective flow controllers 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. In addition, the gas supply unit 20 may include one or more flow modulation devices for modulating or pulsing the flow of at least one process gas.

[0078] 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. Thus, plasma is 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 a plasma generating unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. In addition, by supplying a bias RF signal to at least one bias electrode, a bias potential can be generated on the substrate W to attract ions in the formed plasma to the substrate W.

[0079] 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 configured to be coupled to the antenna 14 and to generate a source RF signal (source RF power) for generating plasma via at least one impedance matching circuit. 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 a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0080] The second RF generating unit 31b is configured to be coupled to at least one bias electrode via at least one impedance matching circuit and 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 100kHz to 60MHz. In one embodiment, the second RF generating unit 31b may also 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 bias electrode. In addition, in various embodiments, at least one of the source RF signal and the bias RF signal may also be pulsed.

[0081] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a bias DC generating unit 32a. In one embodiment, the bias DC generating unit 32a is configured to be connected to at least one bias electrode and generate a bias DC signal. The generated bias DC signal is applied to at least one bias electrode.

[0082] In various embodiments, the bias DC signal can also be pulsed. In this case, a sequence of voltage pulses is applied to at least one bias electrode. The voltage pulse may have a rectangular, trapezoidal, triangular, or a pulse waveform that is a combination of these shapes. In one embodiment, a waveform generator for generating a sequence of voltage pulses from a 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 pulse may have a positive polarity or a negative polarity. In addition, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one cycle. In addition, a bias DC generator 32a may be provided in addition to the RF power supply 31, or a bias DC generator 32a may be provided to replace the second RF generator 31b.

[0083] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil disposed on the same axis. 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, respectively.

[0084] The exhaust system 40 can be connected to a gas outlet 10e, for example, provided at the bottom of the plasma processing chamber 10. The exhaust system 40 can include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump can include a turbomolecular pump, a dry pump, or a combination thereof.

[0085] Figure 3 1 is a flowchart showing an example of a plasma processing method (hereinafter referred to as "this processing method") according to an exemplary embodiment. FIG. 4A to FIG. 4E 1 is a diagram showing an example of a cross-sectional structure of a substrate W. For example, Figure 2 The plasma processing apparatus 1 shown in the figure performs the present processing method on the substrate W. Next, the processing method of the substrate W is described with reference to each figure. Figure 4A The substrate W shown performs Figure 3 In addition, in the following example, Figure 1 and Figure 2 The control unit 2 shown controls Figure 2 The present processing method is performed by using the various components of the plasma processing apparatus 1 shown.

[0086] (Step ST1: Preparing a Substrate)

[0087] In step ST1, a substrate W is prepared in the plasma processing space 10s of the plasma processing chamber 10. In step ST1, the substrate W is at least arranged on the substrate support 11 and held by the electrostatic holding disk 1111. At least a part of the process of forming each structure of the substrate W can be performed in the plasma processing space 10s as a part of step ST1. Alternatively, after all or part of each structure of the substrate W is formed by a device or chamber outside the plasma processing device 1, the substrate W can be moved into the plasma processing space 10s and arranged on the substrate support 11.

[0088] Step ST1 may include a step of setting the temperature of the substrate support 11. The control unit 2 can control the temperature control module to set the temperature of the substrate support 11. As an example, the control unit 2 can set the temperature of the substrate support 11 to be below 80°C, below 70°C, or below 60°C. In addition, when looking down at the substrate support surface, the substrate support 11 may include a plurality of zones. Moreover, the control unit 2 can set and control the temperature of the substrate support 11 in units of each zone.

[0089] As an example, the substrate W prepared in the plasma processing chamber 10 has Figure 4A The cross-sectional structure shown. The substrate W includes a base film UF, a metal compound film MF, a silicon-containing film SF-1, a carbon-containing film CF, a silicon-containing film SF-2, and a mask MK. The mask MK is an example of a mask and an EUV resist film. In addition, the silicon-containing films SF-1 and SF-2 are also collectively referred to as "silicon-containing films SF".

[0090] The base film UF may be an organic film, a dielectric film, a metal film, a semiconductor film, etc. formed on a silicon wafer. In addition, the base film UF may be a silicon wafer. In addition, the base film UF may be composed of a plurality of films stacked.

[0091] The metal compound film MF is a film containing a metal or a semiconductor. As an example, the metal compound MF can be a polysilicon film, a titanium nitride (TiN) film, a tungsten carbide (WC) film, or a tungsten silicide (WSi) film.

[0092] The silicon-containing films SF-1 and SF-2 can be films containing silicon (Si). The silicon-containing films SF-1 and SF-2 can be inorganic films containing silicon. The silicon-containing film SF can include a silicon oxide film or a silicon nitride film. As an example, the silicon-containing film is a SiO2 film or a SiON film. The silicon-containing film can be any film containing silicon, or it can be a film having other film types. In addition, the silicon-containing film SF can also include a silicon film (for example, an amorphous silicon film or a polycrystalline silicon film). In addition, the silicon-containing film SF can include at least one of a silicon nitride film, a polycrystalline silicon film, a carbon-containing silicon film, and a low dielectric constant film. The carbon-containing silicon film can include a SiC film and / or a SiOC film. The low dielectric constant film contains silicon and can be used as an interlayer insulating film. In addition, the silicon-containing film SF can be a spin-on glass (SOG) film or a silicon-containing anti-reflection (SiARC) film. In addition, the silicon-containing film SF-1 can include a semimetal and / or a metal. As an example, the silicon-containing film SF-1 can be a SiO2 film, a boron silicon film (BSi), a tungsten silicon film (WSi), or a SiN film. In addition, as an example, the silicon-containing film SF-2 can be a SOG film, a SiON film, a SiC film, a SiOC film, or an amorphous silicon film.

[0093] In addition, the silicon-containing film SF may include two or more silicon-containing films having different film types. The two or more silicon-containing films may include a silicon oxide film and a silicon nitride film. The silicon-containing film SF may, for example, be a multilayer film including one or more silicon oxide films and one or more silicon nitride films stacked alternately. The silicon-containing film SF may also be a multilayer film including multiple silicon oxide films and multiple silicon nitride films stacked alternately. Alternatively, the two or more silicon-containing films may also include a silicon oxide film and a silicon film. The silicon-containing film SF may, for example, be a multilayer film including one or more silicon oxide films and one or more silicon films stacked alternately. The silicon-containing film SF may also be a multilayer film including multiple silicon oxide films and multiple polysilicon films stacked alternately. Alternatively, the two or more silicon-containing films may also include a silicon oxide film, a silicon nitride film, and a silicon film.

[0094] In addition, the silicon-containing film SF-1 may be a film having higher etching resistance than the silicon-containing film SF-2. The etching resistance may be, for example, resistance to etching using fluorocarbon gas and / or hydrofluorocarbon gas as a processing gas. In addition, the silicon-containing film SF-2 may be thinner than the silicon-containing film SF-1. In addition, the silicon-containing film SF-2 may be thinner than the mask MK and / or the carbon-containing film CF.

[0095] The carbon-containing film CF may be a film containing carbon. The carbon-containing film CF may be a film containing an organic material or a film containing an inorganic material. As an example, the carbon-containing film CF is a spin-on carbon (SOC film) or an amorphous carbon (ACL) film.

[0096] The mask MK can be a metal-containing film. The metal-containing film can be a tin-containing film. The mask MK is formed of a material having an etching rate lower than that of the silicon-containing film SF-2 in step ST2. The mask MK can be a resist film or a photoresist film for EUV. As an example, the photoresist film for EUV can be a tin-containing film. As an example, the tin-containing film can include tin oxide and / or tin hydroxide. In addition, as an example, the photoresist film for EUV can be a metal-containing film containing at least one metal selected from the group consisting of iodine (I), tellurium (Te), antimony (Sb), indium (In), silver (Ag), titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), germanium (Ge), arsenic (As) and hafnium (Hf).

[0097] The mask MK has an opening pattern that defines at least one opening OP on the silicon-containing film SF-2. The mask MK has at least one sidewall outside the periphery of the mask MK. The opening OP is a closed space defined by the sidewall. When looking down at the substrate W, the at least one opening OP defined by the mask MK can have any shape. The shape can include a circular shape, an elliptical shape, a rectangular shape, a linear shape, etc. When looking down at the substrate W, the opening pattern of the mask MK can include an array pattern in which a plurality of openings OP having a hole shape are regularly arranged. The hole shape can include a circular shape, an elliptical shape, a rectangular shape, etc. In addition, when looking down at the substrate W, the opening pattern of the mask MK can include a line width / line spacing (L / S) pattern in which a plurality of openings OP having a line shape are arranged at a certain interval. The spacing of the openings OP (the distance between the centers of the mask MK) can be less than 100nm. Alternatively, the width of the opening OP can be less than 30nm. In the case where the opening OP has a hole shape, the width can be the diameter of the hole. In addition, in the case where the opening pattern has a line / space pattern, the width may be the width of the line or the space. In addition, the thickness of the silicon-containing film SF-1 or SF-2 may be 40 nm or less or 20 nm or less.

[0098] In the opening OP defined by the mask MK, the surface (upper surface) of the silicon-containing film SF-2 is exposed. In the step ST2 described later, the silicon-containing film SF-2, the carbon-containing film CF, the silicon-containing film SF-1, and the metal compound film MF are etched based on the shape of the opening OP defined by the mask MK. In addition, a recessed portion RC such as a hole or a groove is formed in each film. The one or more recessed portions RC formed in each film have the shape of each opening OP based on the one or more openings OP when the substrate W is viewed from above.

[0099] In addition, the opening pattern of the mask MK may include defects. As an example, the defects of the opening pattern may include etching residues generated when the mask MK forms the opening pattern. The etching residues may exist on the side walls of the mask MK for defining the opening OP, the bottom of the opening OP (that is, the surface of the silicon-containing film SF-2) (as an example, refer to Fig. 6A ).

[0100] The substrate W may further include a film containing at least one of carbon and metal between the mask MK and the silicon-containing film SF-2. In one embodiment, the film may function as an antireflection film.

[0101] (Step ST2: Etching)

[0102] In step ST2, each film arranged below the mask MK in the substrate W is etched. Step ST2 includes a step of etching the silicon-containing film SF-2 (step ST21), a step of etching the carbon-containing film CF (step ST22), a step of etching the silicon-containing film SF-1 (step ST23), and a step of etching the metal compound film MF (step ST24).

[0103] Each process of process ST2 may include a process of supplying a process gas into the plasma processing chamber 10, a process of supplying a source RF signal, and a process of supplying a bias RF signal. In each process, active species (ions, free radicals) of plasma are generated from the process gas and each film is etched using the active species. In addition, the order of starting to supply the process gas, the source RF signal, and the bias signal is arbitrary. The bias signal supplied in each process of process ST2 may be a bias RF signal or a bias DC signal. When the bias signal supplied in each process of process ST2 is a bias RF signal, the effective value of the power of the bias RF signal (hereinafter also referred to as "power") may be less than 2kW or less than 1kW. When the bias signal supplied in each process of process ST2 is a bias DC signal, the effective value of the voltage of the bias DC signal (hereinafter also referred to as "voltage") may be less than 2kV or less than 1kV. In addition, the bias DC signal is a signal containing a sequence of more than one DC pulse. The voltage of the DC pulse may have a negative polarity. In addition, plasma may be continuously generated in the plasma processing chamber 10 during two or more consecutive steps in step ST2. That is, plasma may be continuously generated during the two or more consecutive steps. Thus, particles generated in the plasma processing chamber 10 may be reduced.

[0104] In each step of step ST2, a processing gas is supplied into the plasma processing chamber 10. The type of processing gas can be appropriately selected based on the material of the film to be etched in each step, the thickness of the film, the material of the film above and / or below the film, the pattern of the film serving as a mask, and the like.

[0105] In each step of step ST2, the pressure in plasma processing chamber 10 may be appropriately set. For example, the pressure in plasma processing chamber 10 may be set to 50 mTorr or less, 30 mTorr or less, or 10 mTorr or less.

[0106] (Step ST21: Etching the Silicon-Containing Film SF-2)

[0107] Then, if Figure 4B As shown, in step ST21, the silicon-containing film SF-2 is etched. As an example, the silicon-containing film SF-2 can be etched using a plasma generated from a processing gas containing a fluorocarbon gas and / or a hydrofluorocarbon gas. In step ST21, when the substrate W is etched using the plasma generated from the processing gas, the mask MK is used as a mask to etch the silicon-containing film SF-2, thereby forming a recess RC in the silicon-containing film SF-2. The recess RC formed in the silicon-containing film SF-2 is an example of a first recess. In addition, at the bottom of the recess RC, the carbon-containing film CF is exposed. In addition, in the etching of the silicon-containing film SF-2, a portion of the mask MK can also be etched. In addition, in the case where the opening pattern of the mask MK contains defects including etching residues, the silicon-containing film SF-2 can be etched using the etching residues as a mask. That is, the pattern formed in the silicon-containing film SF-2 through the recess RC can also contain defects based on the etching residues.

[0108] (Step ST22: Etching the Carbon-Containing Film CF)

[0109] Then, if Figure 4C As shown, in step ST22, the carbon-containing film CF is etched. As an example, the carbon-containing film CF can be etched using a plasma generated from a processing gas containing hydrogen, halogens, and oxygen. In addition, as an example, the processing gas may contain one or more gases composed of molecules containing hydrogen, bromine, chlorine, and / or iodine. As an example, the gas is H2, Br2, Cl2, HBr, HCl, HI, etc. The processing gas may contain one or more gases composed of molecules containing oxygen. As an example, the gas is O2, CO2, COS, etc. In addition, the processing gas may contain inactive gases such as He, Ar, and N2.

[0110] As an example, when the mask MK is a tin-containing film, in step ST22, when the substrate W is etched using the plasma generated from the processing gas, as shown in FIG. Figure 4C As shown, the mask MK is removed. Furthermore, the carbon-containing film CF is etched using the silicon-containing film SF-2 as a mask, thereby forming a recess RC in the carbon-containing film CF. The recess RC formed in the carbon-containing film CF is an example of a second recess. In addition, at the bottom of the recess RC, the silicon-containing film SF-1 is exposed. In addition, during the etching of the carbon-containing film CF, a portion of the silicon-containing film SF-2 may also be etched. In addition, in a case where the opening pattern of the mask MK includes defects including etching residues, the carbon-containing film CF may be etched using the silicon-containing film SF-2 including defects based on the etching residues as a mask. That is, the pattern formed in the carbon-containing film CF through the recess RC may also include defects based on the etching residues.

[0111] (Step ST23: Etching the Silicon-Containing Film SF-1)

[0112] Then, if Figure 4D As shown, in step ST23, the silicon-containing film SF-1 is etched. As an example, the silicon-containing film SF-1 can be etched using plasma generated from a processing gas containing one or more gases, wherein the one or more gases contain carbon, hydrogen, and fluorine. The processing gas contains one or more gases. Here, the one or more gases can contain hydrogen, carbon, and fluorine, respectively. In addition, when the one or more gases are multiple gases, one of the multiple gases can contain one or more of hydrogen, carbon, and fluorine, and a part or all of the remaining one or more gases of the multiple gases can contain the remaining parts of hydrogen, carbon, and fluorine.

[0113] The processing gas used in step ST23 may include a gas capable of generating hydrogen fluoride (HF) species in plasma processing in plasma processing chamber 10. The hydrogen fluoride species functions as an etchant for etching the silicon-containing film SF-1 in step ST23.

[0114] The gas containing carbon, hydrogen and fluorine may be at least one gas selected from the group consisting of hydrofluorocarbons. Hydrofluorocarbons are, for example, at least one of CH2F2, CHF3 or CH3F. Hydrofluorocarbons may contain more than two carbon atoms, or more than two and less than six carbon atoms. Hydrofluorocarbons may contain, for example, two carbon atoms, such as C2HF5, C2H2F4, C2H3F3, C2H4F2, etc. Hydrofluorocarbons may also contain, for example, three or four carbon atoms, such as C3HF7, C3H2F2, C3H2F4, C3H2F6, C3H3F5, C4H2F6, C4H5F5, C4H2F8, etc. Hydrofluorocarbon gas may also contain, for example, five carbon atoms, such as C5H2F6, C5H2F 10 , C5H3F7, etc. As an embodiment, the hydrofluorocarbon gas includes at least one selected from the group consisting of C3H2F4, C3H2F6, C4H2F6, and C4H2F8. In addition, the processing gas may include hydrogen fluoride (HF) as a gas capable of generating hydrogen fluoride (HF) species in the plasma processing chamber 10 during plasma processing. In addition, in the processing gas, the ratio of the number of hydrogen atoms to the number of fluorine atoms may be greater than 0.3, greater than 0.4, or greater than 0.5. In addition, in the processing gas, the ratio of the number of hydrogen atoms to the number of carbon atoms may be greater than 1.0, greater than 1.5, or greater than 2.0.

[0115] In addition, the processing gas may include a mixed gas that can generate hydrogen fluoride species in the plasma processing chamber 10 during plasma processing as a gas containing hydrogen and fluorine. The mixed gas that can generate hydrogen fluoride species may include a hydrogen source and a fluorine source. The hydrogen source may be, for example, H2, NH3, H2O, H2O2, or a hydrocarbon (CH4, C3H6, etc.). The fluorine source may be BF3, NF3, PF3, PF5, SF6, WF6, XeF2, or a fluorocarbon. As an example, the mixed gas that can generate hydrogen fluoride species is a mixed gas of nitrogen trifluoride (NF3) and hydrogen (H2).

[0116] In addition, the process gas may contain hydrocarbons (C x H y ), fluorocarbons (C v F w ) as the carbon-containing gas. Here, x, y, v and w are natural numbers. The hydrocarbon compound may include, for example, CH4, C2H6, C3H6, C3H8 or C4H 10 The fluorocarbon compound may include, for example, CF4, C2F2, C2F4, C3F8, C4F6, C4F8, or C5F8, etc. Chemical species generated from these carbon-containing gases can protect the mask MK.

[0117] The carbon-containing gas may be a straight-chain gas having an unsaturated bond. As a straight-chain carbon-containing gas having an unsaturated bond, for example, at least one gas selected from the group consisting of C3F6 (hexafluoropropane) gas, C4F8 (octafluoro-1-butene, octafluoro-2-butene) gas, C3H2F4 (1,3,3,3-tetrafluoropropylene) gas, C4H2F6 (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas, C4F8O (pentafluoroethyl trifluorovinyl ether) gas, CF3COF gas (1,2,2,2-tetrafluoroethane-1-one), CHF2COF (difluoroacetyl fluoride) gas, and COF2 (carbonyl fluoride) gas may be used. These gases are gases with relatively low global warming potential (GWP), and therefore have significance for improving the greenhouse effect.

[0118] In addition, the processing gas can also contain at least one phosphorus-containing molecule. The phosphorus-containing molecule can be tetraphosphorus decoxide (P4O 10 ), tetraphosphorus octoxide (P4O8), tetraphosphorus hexoxide (P4O6) and other oxides. Tetraphosphorus decoxide is sometimes called diphosphorus pentoxide (P2O5). Phosphorus-containing molecules can be halides (phosphorus halides) such as phosphorus trifluoride (PF3), phosphorus pentafluoride (PF5), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), phosphorus tribromide (PBr3), phosphorus pentabromide (PBr5), and phosphorus iodide (PI3). That is, the molecule containing phosphorus can be a fluoride (phosphorus fluoride) containing fluorine as a halogen element. Alternatively, the molecule containing phosphorus can also contain a halogen element other than fluorine as a halogen element. The phosphorus-containing molecule can be a phosphorus halide such as phosphoryl fluoride (POF3), phosphoryl chloride (POCl3), and phosphoryl bromide (POBr3). The phosphorus-containing molecule can be phosphine (PH3), calcium phosphide (Ca3P2, etc.), phosphoric acid (H3PO4), sodium phosphate (Na3PO4), hexafluorophosphoric acid (HPF6), etc. The phosphorus-containing molecules can be fluorophosphine (H x PF y ). Here, the sum of x and y is 3 or 5. As fluorophosphine, HPF2 and H2PF3 are exemplified. The processing gas may contain one or more of the above-mentioned phosphorus-containing molecules as at least one phosphorus-containing molecule. For example, the processing gas may contain at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3 or PBr5 as at least one phosphorus-containing molecule. In addition, as at least one phosphorus-containing molecule, it may contain a F b (a and b are positive integers) and PC c H d F eAt least one selected from the group consisting of (c, d and e are positive integers). In addition, when each phosphorus-containing molecule contained in the processing gas is liquid or solid, each phosphorus-containing molecule can be vaporized by heating or the like and supplied into the plasma processing chamber 10 .

[0119] In addition, the processing gas may contain halogen-containing molecules. The halogen-containing molecules may not contain carbon. The halogen-containing molecules may be fluorine-containing molecules or halogen-containing molecules containing halogen elements other than fluorine. Fluorine-containing molecules may include gases such as nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), and boron trifluoride (BF3). Halogen-containing molecules containing halogen elements other than fluorine may be, for example, at least one selected from the group consisting of chlorine-containing gases, bromine-containing gases, and iodine. Chlorine-containing gases are, for example, chlorine (Cl2), silicon dichloride (SiCl2), silicon tetrachloride (SiCl4), carbon tetrachloride (CCl4), dichlorosilane (SiH2Cl2), hexachlorodisilane (Si2Cl6), trichloromethane (CHCl3), sulfonyl chloride (SO2Cl2), boron trichloride (BCl3), and other gases. Bromine-containing gases include, for example, bromine (Br2), hydrogen bromide (HBr), dibromodifluoromethane (CBr2F2), bromopentafluoroethane (C2F5Br), phosphorus tribromide (PBr3), phosphorus pentabromide (PBr5), phosphorus oxybromide (POBr3), boron tribromide (BBr3), etc. Iodine-containing gases include, for example, hydrogen iodide (HI), trifluoroiodomethane (CF3I), pentafluoroiodoethane (C2F5I), perfluoroiodopropane (C3F7I), iodine pentafluoride (IF5), iodine heptafluoride (IF7), iodine (I2), phosphorus triiodide (PI3), etc. Chemical species generated from these halogen-containing molecules can be used to control the shape of the recess formed by plasma etching.

[0120] The processing gas may contain oxygen-containing molecules. The oxygen-containing molecules may include, for example, O2, CO2, or CO. In addition, the processing gas may contain a rare gas such as Ar, Kr, or Xe.

[0121] In addition, Figure 2In the plasma processing apparatus 1, the processing gas may be supplied to the plasma processing chamber 10 from one or both of the central gas injection part 131 and the side gas injection part. As an example, the flow rate of the carbon-containing gas supplied from the side gas injection part may be greater than the flow rate of the carbon-containing gas supplied from the central gas injection part 131. That is, the ratio of the flow rate of the carbon-containing gas supplied from the central gas injection part 131 to the flow rate of the carbon-containing gas contained in the processing gas may be 50% or less, and the ratio of the flow rate of the carbon-containing gas supplied from the side gas injection part to the flow rate of the carbon-containing gas contained in the processing gas may be 50% or more. In addition, the ratio of the flow rate of the carbon-containing gas supplied from the central gas injection part 131 to the flow rate of the carbon-containing gas contained in the processing gas may be 20% or less, and the ratio of the flow rate of the carbon-containing gas supplied from the side gas injection part to the flow rate of the carbon-containing gas contained in the processing gas may be 80% or more. In addition, the ratio of the flow rate of the carbon-containing gas supplied from the central gas injection part 131 to the flow rate of the carbon-containing gas contained in the processing gas may be 10% or less, and the ratio of the flow rate of the carbon-containing gas supplied from the side gas injection part to the flow rate of the carbon-containing gas contained in the processing gas may be 90% or more. In addition, the ratio of the flow rate of the carbon-containing gas supplied from the central gas injection part 131 to the flow rate of the carbon-containing gas contained in the processing gas may be 5% or less, and the ratio of the flow rate of the carbon-containing gas supplied from the side gas injection part to the flow rate of the carbon-containing gas contained in the processing gas may be 95% or more. In addition, the ratio of the flow rate of the carbon-containing gas supplied from the side gas injection part to the flow rate of the carbon-containing gas contained in the processing gas may be 100%.

[0122] In addition, as an example, the number of carbon atoms contained in the carbon-containing gas supplied from the side gas injection part among the processing gases supplied into the plasma processing chamber 10 may be greater than the number of carbon atoms contained in the carbon-containing gas supplied from the central gas injection part 131 .

[0123] By supplying at least a portion of the carbon-containing gas included in the processing gas into the plasma processing chamber 10 from the side gas injection portion, the uniformity of the etching rate of the etching film and / or the uniformity of the size of the recessed portion formed in the etching film can be improved within the surface of the substrate W.

[0124] Next, the source RF signal and the bias signal supplied in step ST23 are described. As an example, the source RF signal supplied in step ST23 can be supplied to Figure 2 The upper electrode or Figure 2The antenna 14 of the plasma processing device 1 in the embodiment of the present invention is a top electrode. The source RF signal may be a continuous wave of RF or a pulse wave. The power of the source RF signal is greater than the power of the bias signal. As an example, the power of the source RF signal may be 300 W or more. In addition, the power of the source RF signal may be 500 W or more, 1000 W or more, or 2000 W or more.

[0125] As an example, the bias signal supplied in step ST23 is supplied to Figure 2 The substrate support 11 of the embodiment of the present invention. The bias signal can be supplied to a component in the substrate support 11 that can function as a bias electrode. The bias signal can be an RF signal. The power of the bias signal is less than the power of the source RF signal. As an example, the power of the bias signal can be less than 200 W. In addition, the power of the bias signal can be less than 100 W or less than 50 W. In addition, as an example, the power of the bias signal can also be greater than the power of the source RF signal.

[0126] In step ST23, when etching the substrate W using plasma generated from the processing gas, the silicon-containing film SF-1 is etched using the silicon-containing film SF-2 and / or the carbon-containing film CF as a mask, thereby forming a recess RC in the silicon-containing film SF-1. The recess RC formed in the silicon-containing film SF-1 is an example of a third recess. In addition, at the bottom of the recess RC, the metal compound MF is exposed. In addition, the silicon-containing film SF-2 can be etched under the same etching conditions as the silicon-containing film SF-1. The etching conditions can include the type of processing gas, the power of the source RF signal, the power of the bias signal, and the pressure in the plasma processing chamber 10.

[0127] In addition, in step ST23, a deposit containing a metal generated in step ST21 and / or step ST22 may be removed. The metal may be a metal contained in mask MK. In addition, as an example, the metal may be tin (Sn). The deposit may be a residue of a compound containing the metal generated during etching in step ST21 and / or step ST22. In addition, the deposit may be a deposit attached to substrate W, or may be a deposit attached to the inner wall of plasma processing chamber 10.

[0128] (Other examples of step ST1)

[0129] Figure 5 1 is a flowchart showing an example of a process (ST1) for preparing a substrate. In this example, the process ST1 includes a process (ST11a) for configuring a substrate, a process (ST12a) for removing scum, a process (ST13a) for forming a deposit, and a process (ST14a) for etching an anti-reflection film. FIG. 6A to FIG. 6Dis a diagram showing an example of a cross-sectional structure of a substrate W in step ST1. Figure 5 In each process shown, the Figure 3 At least one gas among the one or two or more gases exemplified in each step shown.

[0130] First, in step ST11 a , the substrate W is placed on the substrate support 11 . Fig. 6A FIG. 2 shows an example of a cross-sectional structure of a substrate W disposed on the substrate support portion 11. Fig. 6A In the example shown, the substrate W further includes an anti-reflection film AF on the silicon-containing film SF-2. That is, the substrate W further includes an anti-reflection film AF between the silicon-containing film SF-2 and the mask MK. In addition, in step ST11a, an opening pattern including OP may be formed in the mask MK after the substrate W is arranged on the substrate support 11. The opening pattern may be formed by dry etching or dry developing the mask MK.

[0131] The anti-reflection film AF may be a film containing at least one of carbon and metal. In one embodiment, the anti-reflection film AF may be a carbon-containing film or a metal-containing film.

[0132] exist Fig. 6A In the example shown, at least a portion of the side surface SS of the mask MK may have a portion SC extending toward the opening OP. The portion SC may be, for example, a portion SC1 existing at the outer edge of the bottom surface BS of the opening OP. In addition, the portion SC may be a convex portion SC2 protruding from the side surface SS toward the opening OP in the area separated upward from the bottom surface BS in the side surface SS. The portion SC (SC1, SC2) may be scum of the mask MK. The scum may be, for example, a residual portion of the resist that is not completely removed in the process (for example, the development process) of forming the opening OP in the mask MF. In addition to the scum constituting the above-mentioned portion SC, the scum of the mask MK may also include, for example, scum SC3 existing in isolation on the bottom surface BS of the opening OP and not connected to the side surface SS of the mask MK. In addition, the scum of the mask MK may also include scum extending in a manner of transversely cutting the opening OP or bridging between the side surfaces SS (not shown). In addition, the side surface SS of the mask MK may also have concave portions (not shown) such as depressions and cracks (interruptions of patterns including line patterns, etc.).

[0133] Next, in step ST12a, the scum is removed. In step ST12a, the scum can be removed using plasma generated from the first process gas. In one embodiment, the first process gas can include a gas containing oxygen. As an example, the gas containing oxygen can be at least one gas selected from the group consisting of oxygen (O2), carbon monoxide gas (CO), carbon dioxide gas (CO2), carbonyl fluoride gas (COF2), carbonyl sulfide gas (COS), and phosphorus oxychloride (POCl3).

[0134] Figure 6B 1 is a diagram showing an example of a cross-sectional structure of the substrate W after the step ST12a is performed. Figure 6B As shown, by the process ST12a, the portion SC which is the scum of the mask MK is removed. In addition, a portion of the upper surface TS and / or the side surface SS of the mask MK can also be etched. The opening width of the opening OP after performing the process ST12a can be larger than the opening width of the opening OP before performing the process ST12a.

[0135] Next, in step ST13a, a deposit is formed. Figure 6C FIG. 1 is a diagram showing an example of a cross-sectional structure of a substrate W after executing step ST13a. Figure 6C As shown, the deposit DF can be formed on the mask MK. The deposit DF formed on the upper surface TS can be thicker than the deposit DF formed on the side surface SS of the mask MK. In addition, the deposit DF may not be formed on the bottom surface BS of the opening OP (that is, the surface of the anti-reflection film AF). The upper surface TS of the mask MK is an example of a surface included in the first area. The side surface SS is an example of a surface included in the second area.

[0136] In step ST13a, the deposit DF may include at least one selected from the group consisting of carbon, silicon, and metal. In one embodiment, the deposit DF may be a carbon-containing film, a silicon-containing film, or a metal-containing film. The deposit DF may be formed by plasma generated from a second process gas. The second process gas may include a gas containing at least one selected from the group consisting of carbon, silicon, and metal. In one embodiment, the second process gas may include a gas containing carbon and hydrogen, a gas containing silicon and halogen, and / or a gas containing metal and halogen.

[0137] Next, in step ST14a, the anti-reflection film AF is etched. In step ST14a, the anti-reflection film AF is etched using plasma generated from a third process gas. In one embodiment, the third process gas may include a gas containing oxygen and / or a gas containing halogen. As an example, in the case where the anti-reflection film AF is a carbon-containing film, the third process gas may include at least one gas selected from the group consisting of oxygen (O2), carbon monoxide gas (CO), carbon dioxide gas (CO2), carbonyl fluoride gas (COF2), carbonyl sulfide gas (COS) and phosphorus oxychloride (POCl3). As an example, in the case where the anti-reflection film AF is a metal-containing film, the third process gas may include at least one gas selected from the group consisting of fluorine gas (F2), hydrogen fluoride gas (HF), chlorine gas (Cl2), hydrogen chloride gas (HCl), boron trichloride gas (BCl3), bromine gas (Br2) and hydrogen bromide gas (HBr).

[0138] Fig.6D 1 is a diagram showing an example of a cross-sectional structure of the substrate W after the step ST14a is performed. Fig.6D As shown, in step ST14a, the portion of the anti-reflection film AF exposed in the opening OP is etched. That is, in step ST14a, the anti-reflection film AF can be etched using the mask MK and / or the deposit DF as a mask. In addition, in step ST14a, a portion of the deposit DF can be etched together with the anti-reflection film AF. That is, in step ST14a, the opening width of the opening OP can be widened.

[0139] (Other examples of step ST1)

[0140] Figure 7 1 is a flowchart showing an example of a process (ST1) for preparing a substrate. In this example, the process ST1 includes a process (ST11b) for configuring a substrate, a process (ST12b) for removing scum, a process (ST13b) for forming a deposit, and a process (ST14b) for etching an anti-reflection film. FIG. 8A to FIG. 8D is a diagram showing an example of a cross-sectional structure of a substrate W in step ST1. Figure 7 In each process shown, the Figure 3 At least one of the one or two or more gases exemplified in each step shown.

[0141] First, in step ST12b, the substrate W is placed on the substrate support 11. In step ST11b, the same substrate as in step ST11a (see Fig. 8A ) is arranged on the substrate support portion 11 in the same manner as in step ST11a. Next, in step ST12b, scum is removed in the same manner as in step ST12a (see Figure 8B ).

[0142] Next, in step ST13b, a deposited film DF is formed. In this example, in step ST13b, the deposit DF is formed into a stacked structure having deposits DF-1 and DF-2, which is different from step ST13a. That is, first, the deposit DF-1 is formed in the same manner as in step ST13a. Next, in step ST13b, the deposit DF-2 is formed on the deposit DF-1. The deposit DF-2 may have a composition different from that of the deposit DF-1. As an example, when the deposit DF-1 is a deposit containing carbon, the deposit DF-2 may be a deposit containing silicon.

[0143] Next, in step ST14b, the anti-reflection film AF is etched. In step ST14b, the anti-reflection film AF can be etched in the same manner as in step ST14a. That is, the anti-reflection film AF can be etched using the mask MK, the deposit DF-1, and the deposit DF-2 as masks. In addition, in step ST14b, a portion of the etched deposit DF-1 and / or the deposit DF-2 can be etched together with the anti-reflection film AF.

[0144] (Other examples of step ST1)

[0145] Fig. 9 1 is a flowchart showing an example of a process (ST1) for preparing a substrate. In this example, the process ST1 includes a process (ST11c) for configuring the substrate, a process (ST12c) for forming a deposit, a process (ST13c) for removing scum, and a process (ST14c) for etching an anti-reflection film. FIG. 10A to FIG. 10C is a diagram showing an example of a cross-sectional structure of a substrate W in step ST1. Fig. 9 In each process shown, the Figure 3 At least one of the one or two or more gases exemplified in each step shown.

[0146] First, in step ST11c, the substrate W is placed on the substrate support 11. In step ST11c, the same substrate as in step ST11a (see Fig. 8A ) is arranged on the substrate support portion 11 in the same manner as in step ST11a.

[0147] Next, in step ST12c, a deposit DF is formed. In step ST12c, the deposit DF can be formed in the same manner as in step ST13a. In one embodiment, the deposit DF can be formed in a manner that covers the scum on the mask MK. In one embodiment, the deposit DF can also be formed in a manner that a portion of the scum on the mask MK protrudes from the deposit DF. That is, the deposit DF can be formed on the mask MK in a manner that a portion of the scum is exposed in the opening OP.

[0148] Next, in step ST13c, the anti-reflection film AF is etched. In step ST13c, the anti-reflection film AF can be etched in the same manner as in step ST14a. That is, the anti-reflection film AF can be etched using the mask MK and the deposit DF as masks. In addition, in step ST13c, in addition to the anti-reflection film AF, the scum and / or the deposit DF can also be etched. Here, a part or all of the scum can be etched. As an example, the part of the scum that is exposed from the deposit DF to the opening OP can be etched.

[0149] (Other Examples of Step ST23)

[0150] Fig.11 is a flowchart showing an example of step ST23. In one embodiment, step ST23 includes a step of generating plasma from a fourth process gas (ST23-1) and a step of generating plasma from a fifth process gas (ST23-2). Fig.11 In each process shown, the Figure 3 At least one of the one or two or more gases exemplified in each step shown.

[0151] In step ST23-1, the silicon-containing film SF-1 is etched using plasma generated from a fourth process gas. The fourth process gas may include a gas containing fluorine. In one embodiment, the gas containing fluorine may be Figure 3 The fourth process gas may include a fluorocarbon gas and / or a hydrogen fluoride gas. The fourth process gas may include a hydrofluorocarbon gas.

[0152] Fig. 12A FIG. 1 is a diagram showing an example of a cross-sectional structure of the substrate W after the step ST23-1 is performed. In one embodiment, the silicon-containing film SF-1 is etched in the step ST23-1. Fig.11As shown in A, a recess RC having a conical cross-section can be formed. As an example, after executing step ST23-1, the opening width d1 of the recess RC on the carbon-containing film CF side is larger than the opening width d2 on the metal-containing film MF side or the base film UF side. As an example, the opening width d1 can be the opening width of the recess RC at a position closer to the carbon-containing film CF than the center in the depth direction of the recess RC. In addition, the opening width d2 can be the opening width of the recess RC at a position closer to the metal-containing film MF or the base film UF than the center in the depth direction of the recess RC. In addition, in step ST23-1, the film directly below the silicon-containing film SF-1 (at Fig. 12A In the example, the metal-containing film MF) may be exposed or not.

[0153] In step ST23-2, the silicon-containing film SF-1 is further etched using plasma generated from a fifth process gas. The fifth process gas may include hydrogen fluoride gas and a carbon-containing gas. In one embodiment, the carbon-containing gas may include a hydrofluorocarbon gas having a carbon number of 3 or more. As an example, the carbon-containing gas may include C4F6. In addition, in one embodiment, the fifth process gas may further include an oxygen-based gas. As an example, the oxygen-based gas may be O2.

[0154] Fig. 12B FIG. 2 is a diagram showing an example of a cross-sectional structure of the substrate W after the step ST23-2 is performed. In one embodiment, the silicon-containing film SF-1 is further etched in the concave portion RC by the step ST23-2. Fig. 12B As shown, the cross-sectional shape of the recess RC can be made larger than Fig. 12A A gentle tapered shape. That is, after executing step ST23-2, the angle of the side of the recess RC can be closer to vertical than before executing step ST23-2. In one embodiment, the opening width d2 before executing step ST23-2 can become an opening width d2′ that is larger than the opening width d2 after executing step ST23-2. In addition, the opening width d1 before executing step ST23-2 can remain approximately the same as the opening width d1 or become an opening width d1′ that is larger than the opening width d1 after executing step ST23-2. In addition, the opening width d1′ can be approximately the same size as the opening width d2′.

[0155] Furthermore, in one embodiment, Figure 3 , Figure 5 , Figure 7 , Fig. 9 as well as Fig.11Each process can be performed in the same chamber. In addition, in one embodiment, part or all of each process can be performed in different chambers. In one embodiment, each process can be performed in the same chamber without breaking the vacuum. In the case where each process is performed in multiple chambers, each chamber can be connected via a transport chamber that is depressurized compared to atmospheric pressure. The transport chamber of the substrate can be configured so that the substrate can move between the chambers.

[0156] In this processing method, the power of the bias signal is relatively low to etch the silicon-containing film. That is, the energy of the hydrogen fluoride species generated from the processing gas can be suppressed to be low. As a result, a recess can be appropriately formed in the silicon-containing film through a mask such as an EUV resist.

[0157] In addition, in the present processing method, when the mask MK contains a metal, the deposit containing the metal and / or the defects contained in the mask MK can be removed and the silicon-containing film SF can be etched. As a result, the influence of the deposit and / or the defects can be reduced in the etching of the silicon-containing film SF, and thus the defects contained in the silicon-containing film SF can be reduced. In addition, the deposit can be a compound containing the metal generated in the process of etching other films contained in the substrate W. In addition, the defect can be an etching residue of the mask MK generated in the process of forming an opening pattern in the mask MK.

[0158] In addition, in the present processing method, the deposits and / or the defects can be removed and the silicon-containing film SF can be etched, so the roughness of the pattern of the silicon-containing film SF can be improved.

[0159] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the embodiments without departing from the scope and purpose of the present disclosure. For example, a part of the components of a certain embodiment can be added to other embodiments. In addition, a part of the components of a certain embodiment can be replaced with corresponding components of other embodiments. As an example, the present disclosure can include the following methods.

[0160] (Note 1)

[0161] A plasma processing method is a plasma processing method performed in a plasma processing device.

[0162] The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber.

[0163] The plasma treatment method comprises the following steps:

[0164] Step (a) is a preparation step of preparing a substrate on the substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern having an opening width of 30 nm or less; and

[0165] step (b), generating plasma in the chamber and etching the silicon-containing film through the mask to form a recess in the silicon-containing film,

[0166] Wherein, the step (b) comprises the following steps:

[0167] Step (b-1), supplying a processing gas containing hydrogen fluoride into the chamber;

[0168] Step (b-2), generating plasma from the processing gas in the chamber; and

[0169] In step (b-3), a bias signal is supplied to the substrate support portion, wherein the bias signal is a bias RF signal having an effective value of power less than 2 kW, or a bias DC signal including a sequence of negative-polarity DC pulses having an effective value of voltage less than 2 kV.

[0170] (Note 2)

[0171] In the plasma processing method described in Supplementary Note 1,

[0172] The substrate supporting surface of the substrate supporting portion for supporting the substrate includes a plurality of regions.

[0173] The step (a) includes setting the temperature of the substrate support portion in units of the zones.

[0174] In the step (b), the silicon-containing film is etched in a state where the temperature of the substrate support portion is set in units of zones.

[0175] (Note 3)

[0176] In the plasma processing method described in Supplement 1 or 2,

[0177] The substrate support portion includes a temperature control module, which is configured to include one or more heaters to adjust the temperature of the substrate.

[0178] The step (b) is performed in a state where the temperature of the substrate support is set to 80° C. or less by the temperature control module.

[0179] (Note 4)

[0180] In the plasma processing method described in any one of Supplements 1 to 3,

[0181] The process gas further includes at least one gas selected from the group consisting of a carbon-containing gas, a phosphorus-containing gas, a metal-containing gas, a boron-containing gas, an oxygen-containing gas, and a halogen-containing gas.

[0182] (Note 5)

[0183] In the plasma processing method described in any one of Supplements 1 to 4,

[0184] The process gas includes a phosphorus-containing gas.

[0185] (Note 6)

[0186] In the plasma processing method described in any one of Supplements 1 to 5,

[0187] The process gas includes at least one inert gas selected from the group consisting of a rare gas and a nitrogen gas.

[0188] (Note 7)

[0189] In the plasma processing method described in Supplementary Note 6,

[0190] A ratio of the flow rate of the hydrogen fluoride gas and the inert gas to the total flow rate of the processing gas is 50 volume % or more.

[0191] (Note 8)

[0192] In the plasma processing method described in Supplementary Note 7,

[0193] The ratio of the flow rate of the inert gas to the flow rate of the hydrogen fluoride gas is 0.1 or more and 200 or less.

[0194] (Note 9)

[0195] In the plasma processing method described in any one of Supplements 1 to 8,

[0196] The plasma processing device comprises:

[0197] a first gas injection portion disposed on an upper surface of the chamber so as to face the substrate support portion; and

[0198] a second gas injection portion, which is disposed on a side of the chamber,

[0199] The process gas comprises at least one first gas not containing carbon and at least one second gas containing carbon,

[0200] supplying at least one of the first gases from the first gas injection unit,

[0201] At least one of the second gases is supplied from the second gas injection portion.

[0202] (Note 10)

[0203] In the plasma processing method described in any one of Supplements 1 to 8,

[0204] The plasma processing device comprises:

[0205] A first gas injection portion, which is disposed on an upper surface of the chamber in the chamber; and

[0206] a second gas injection portion, which is disposed in the chamber on a side of the chamber,

[0207] The process gas comprises at least one carbon-containing gas,

[0208] supplying the at least one carbon-containing gas into the chamber from the first gas injection part and the second gas injection part,

[0209] The flow rate of the at least one carbon-containing gas supplied from the second gas injection part into the chamber is greater than the flow rate of the at least one carbon-containing gas supplied from the first gas injection part into the chamber.

[0210] (Note 11)

[0211] In the plasma processing method described in any one of Supplements 1 to 10,

[0212] In the step (b), the pressure in the chamber is set to 50 mTorr or less.

[0213] (Note 12)

[0214] In the plasma processing method according to any one of Supplementary Notes 1 to 11, the mask includes a resist film.

[0215] (Note 13)

[0216] In the plasma processing method described in any one of Supplementary Notes 1 to 12,

[0217] The mask includes an EUV resist film.

[0218] (Note 14)

[0219] In the plasma processing method described in Supplementary Note 12,

[0220] The resist film includes a metal-containing resist.

[0221] (Note 15)

[0222] In the plasma processing method described in any one of Supplements 1 to 14,

[0223] The silicon-containing film has a thickness of 40 nm or less.

[0224] (Note 16)

[0225] In the plasma processing method described in Supplement 14,

[0226] The aspect ratio of the recessed portion formed in the silicon-containing film is 5 or less.

[0227] (Note 17)

[0228] In the plasma processing method described in any one of Supplementary Notes 1 to 16,

[0229] The step (a) comprises the following steps:

[0230] Step (a-1), preparing a substrate including the silicon-containing film, an anti-reflection film on the silicon-containing film, and the mask on the anti-reflection film; and

[0231] In step (a-2), a portion of the antireflection film exposed from the opening pattern and a portion of the mask are removed using plasma generated from a first processing gas containing oxygen.

[0232] (Note 18)

[0233] The plasma etching method described in Supplement 17 includes the following steps:

[0234] Step (a-3), after step (a-2), using a second processing gas to form a deposit of at least one selected from the group consisting of carbon, silicon, and metal in a first region and a second region of the mask, wherein the first region includes an upper surface of the mask and the second region includes a side surface of the mask, the side surface defining the opening pattern; and

[0235] In step (a-4), plasma generated from a third process gas containing oxygen is used to remove at least a portion of the deposit on the second region and a portion of the antireflection film exposed from the opening pattern.

[0236] (Note 19)

[0237] In the plasma etching method according to any one of Supplementary Notes 1 to 18,

[0238] The step (a) comprises the following steps:

[0239] Step (a-1), preparing a substrate including the silicon-containing film, an anti-reflection film on the silicon-containing film, and a mask on the anti-reflection film;

[0240] Step (a-3), after step (a-1), using a second processing gas to form a deposit of at least one selected from the group consisting of carbon, silicon, and metal in a first region and a second region of the mask, wherein the first region includes an upper surface of the mask and the second region includes a side surface of the mask, the side surface defining the opening pattern; and

[0241] In step (a-4), at least a portion of the deposit on the second region and a portion of the anti-reflection film exposed from the opening pattern are removed using a third processing gas.

[0242] (Note 20)

[0243] A plasma processing method is a plasma processing method performed in a plasma processing device.

[0244] The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber.

[0245] The plasma treatment method comprises the following steps:

[0246] Step (a) is a preparation step of preparing a substrate on the substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern; and

[0247] step (b), generating plasma in the chamber and etching the silicon-containing film to form the opening pattern in the silicon-containing film,

[0248] wherein, in the step (a), the width of the openings included in the opening pattern is 30 nm or less,

[0249] The step (b) comprises the following steps:

[0250] Step (b-1), supplying a processing gas containing at least hydrogen and fluorine into the chamber;

[0251] Step (b-2), generating a plasma containing a hydrogen fluoride species from the processing gas in the chamber; and

[0252] In step (b-3), a bias signal is supplied to the substrate support portion, wherein the bias signal is a bias RF signal having an effective value of 2 kW or a bias DC signal including a sequence of negative-polarity DC pulses having an effective value of less than 2 kV.

[0253] (Note 21)

[0254] A plasma processing method is a plasma processing method performed in a plasma processing device.

[0255] The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber.

[0256] The plasma treatment method comprises the following steps:

[0257] Step (a), preparing a substrate, the substrate comprising a first silicon-containing film, a carbon-containing film on the first silicon-containing film, a second silicon-containing film on the carbon-containing film, and a resist film on the second silicon-containing film, wherein the resist film comprises an opening pattern having an opening width of 30 nm or less;

[0258] Step (b), etching the second silicon-containing film through the resist film to form a first recess in the second silicon-containing film;

[0259] step (c), etching the carbon-containing film through the first recess to form a second recess in the carbon-containing film; and

[0260] step (d), etching the first silicon-containing film through the second recess,

[0261] wherein, in the steps (b), (c) and (d), a bias signal having an effective value of less than 2 kW is supplied to the substrate support portion;

[0262] The step (b) comprises the following steps:

[0263] Step (b-1), supplying a processing gas containing at least hydrogen and fluorine; and

[0264] In step (b-2), a plasma containing hydrogen fluoride species is generated from the processing gas.

[0265] (Note 22)

[0266] In the plasma processing method described in Supplementary Note 21,

[0267] The substrate further comprises a base film under the first silicon-containing film,

[0268] The step (d) comprises the following steps:

[0269] Step (d-1), etching the first silicon-containing film using plasma generated from a fourth processing gas containing fluorine to form a third recess in the first silicon-containing film, wherein the opening size of the third recess on the carbon-containing film side is larger than the opening size on the base film side; and

[0270] In step (d-2), the opening size of the third recessed portion on the base film side is enlarged by using plasma generated from a fifth process gas including a hydrogen fluoride gas and a carbon-containing gas.

[0271] (Note 23)

[0272] In the plasma processing method described in Supplementary Note 22,

[0273] The fourth process gas includes at least one of hydrogen fluoride gas and fluorocarbon gas,

[0274] The carbon-containing gas includes a hydrofluorocarbon gas having a carbon number of 3 or more.

[0275] (Note 24)

[0276] In the plasma processing method according to Supplement 22 or 23,

[0277] The plasma is continuously generated during two or more consecutive steps among the steps (b), (c), and (d).

[0278] (Note 25)

[0279] In the plasma processing method described in any one of Supplementary Notes 22 to 24,

[0280] The plasma processing device is an inductively coupled plasma processing device,

[0281] The steps (a), (b), (c) and (d) are performed in the same chamber.

[0282] (Note 26)

[0283] A plasma processing device comprises a chamber, a gas supply unit, a plasma generating unit, a substrate supporting unit arranged in the chamber, and a control unit, wherein:

[0284] The control unit performs the following control:

[0285] Control (a) to prepare a substrate on a substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern having an opening width of 30 nm or less; and

[0286] controlling (b) to generate plasma in the chamber and to etch the silicon-containing film through the mask to form a recess in the silicon-containing film,

[0287] Wherein, in the control (b), the control unit performs the following control:

[0288] Control (b-1) to supply a processing gas containing hydrogen fluoride into the chamber;

[0289] controlling (b-2) to generate plasma from the process gas in the chamber; and

[0290] Control (b-3) to supply a bias signal to the substrate support portion, wherein the bias signal is a bias RF signal having an effective value of power less than 2 kW, or a bias DC signal including a sequence of negative-polarity DC pulses having an effective value of voltage less than 2 kV.

[0291] Description of Reference Numerals

[0292] 1: plasma processing device; 2: control unit; 10: plasma processing chamber; 12: plasma generating unit; 13: central gas injection unit; 14: antenna; 20: gas supply unit; 30: power supply; 31: RF power supply; 32: DC power supply; 52: peripheral gas injection unit; 101: dielectric window; 102: side wall; 111: main body; 111a: central area; 111b: annular area; 131: central gas injection unit; CF: carbon-containing film; MF: metal compound film; MK: mask; OP: opening; RC: recess; SF: silicon-containing film; UF: base film.

Claims

1. A plasma processing method, which is a plasma processing method performed in a plasma processing device, The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber. The plasma treatment method comprises the following steps: Step (a) is a preparation step of preparing a substrate on the substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern having an opening width of 30 nm or less; as well as step (b), generating plasma in the chamber and etching the silicon-containing film through the mask to form a recess in the silicon-containing film, in, The step (b) comprises the following steps: Step (b-1), supplying a processing gas containing hydrogen fluoride into the chamber; Step (b-2), generating plasma from the processing gas in the chamber; as well as Step (b-3), supplying a bias signal to the substrate support portion, wherein the bias signal is a bias RF signal with an effective value of power less than 2kW, or a bias DC signal containing a sequence of negative-polarity DC pulses with an effective value of voltage less than 2kV.

2. The plasma processing method according to claim 1, wherein: The substrate supporting surface of the substrate supporting portion for supporting the substrate includes a plurality of regions. The step (a) includes setting the temperature of the substrate support portion in units of the zones. In the step (b), the silicon-containing film is etched in a state where the temperature of the substrate support portion is set in units of zones.

3. The plasma processing method according to claim 1, wherein: The substrate support portion includes a temperature control module, and the temperature control module is configured to include one or more heaters to adjust the temperature of the substrate. The step (b) is performed in a state where the temperature of the substrate support is set to 80° C. or less by the temperature control module.

4. The plasma processing method according to claim 1, wherein: The process gas further includes at least one gas selected from the group consisting of a carbon-containing gas, a phosphorus-containing gas, a metal-containing gas, a boron-containing gas, an oxygen-containing gas, and a halogen-containing gas.

5. The plasma processing method according to claim 1, wherein: The process gas includes a phosphorus-containing gas.

6. The plasma processing method according to claim 1, wherein: The process gas includes at least one inert gas selected from the group consisting of a rare gas and a nitrogen gas.

7. The plasma processing method according to claim 6, wherein: A ratio of the flow rate of the hydrogen fluoride gas and the inert gas to the total flow rate of the processing gas is 50 volume % or more.

8. The plasma processing method according to claim 7, wherein: The ratio of the flow rate of the inert gas to the flow rate of the hydrogen fluoride gas is 0.1 or more and 200 or less.

9. The plasma processing method according to claim 1, wherein: The plasma processing device comprises: a first gas injection portion disposed on an upper surface of the chamber so as to face the substrate support portion; and a second gas injection portion, which is disposed on a side of the chamber, The process gas comprises at least one first gas not containing carbon and at least one second gas containing carbon, supplying at least one of the first gases from the first gas injection unit, At least one of the second gases is supplied from the second gas injection portion.

10. The plasma processing method according to claim 1, wherein: The plasma processing device comprises: A first gas injection portion, which is disposed on an upper surface of the chamber in the chamber; and a second gas injection portion, which is disposed in the chamber on a side of the chamber, The process gas comprises at least one carbon-containing gas, supplying the at least one carbon-containing gas into the chamber from the first gas injection part and the second gas injection part, The flow rate of the at least one carbon-containing gas supplied from the second gas injection part into the chamber is greater than the flow rate of the at least one carbon-containing gas supplied from the first gas injection part into the chamber.

11. The plasma processing method according to claim 1, wherein: In the step (b), the pressure in the chamber is set to 50 mTorr or less.

12. The plasma processing method according to claim 1, wherein: The mask includes a resist film.

13. The plasma processing method according to claim 1, wherein: The mask includes an EUV resist film.

14. The plasma processing method according to claim 12, wherein: The resist film includes a metal-containing resist.

15. The plasma processing method according to claim 1, wherein: The silicon-containing film has a thickness of 40 nm or less.

16. The plasma processing method according to claim 14, wherein: The aspect ratio of the recessed portion formed in the silicon-containing film is 5 or less.

17. The plasma processing method according to claim 1, wherein: The step (a) comprises the following steps: Step (a-1), preparing a substrate including the silicon-containing film, an anti-reflection film on the silicon-containing film, and the mask on the anti-reflection film; as well as In step (a-2), a portion of the antireflection film exposed from the opening pattern and a portion of the mask are removed using plasma generated from a first processing gas containing oxygen.

18. The plasma etching method according to claim 17, wherein: Including the following processes: Step (a-3), after step (a-2), using a second processing gas to form a deposit of at least one selected from the group consisting of carbon, silicon, and metal in a first region and a second region of the mask, wherein the first region includes an upper surface of the mask and the second region includes a side surface of the mask, wherein the side surface defines the opening pattern; as well as In step (a-4), plasma generated from a third process gas containing oxygen is used to remove at least a portion of the deposit on the second region and a portion of the antireflection film exposed from the opening pattern.

19. The plasma etching method according to claim 1, wherein: The step (a) comprises the following steps: Step (a-1), preparing a substrate including the silicon-containing film, an anti-reflection film on the silicon-containing film, and a mask on the anti-reflection film; Step (a-3), after step (a-1), using a second processing gas to form a deposit of at least one selected from the group consisting of carbon, silicon, and metal in a first region and a second region of the mask, wherein the first region includes an upper surface of the mask and the second region includes a side surface of the mask, wherein the side surface defines the opening pattern; as well as In step (a-4), at least a portion of the deposit on the second region and a portion of the antireflection film exposed from the opening pattern are removed using a third processing gas.

20. A plasma processing method, which is a plasma processing method performed in a plasma processing device, The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber. The plasma treatment method comprises the following steps: Step (a) is a preparation step of preparing a substrate on the substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern; and step (b), generating plasma in the chamber and etching the silicon-containing film through the mask to form a recess in the silicon-containing film, in, In the step (a), the width of the openings included in the opening pattern is 30 nm or less, The step (b) comprises the following steps: Step (b-1), supplying a processing gas containing at least hydrogen and fluorine into the chamber; Step (b-2), generating a plasma containing a hydrogen fluoride species from the processing gas in the chamber; and Step (b-3), supplying a bias signal to the substrate support portion, wherein the bias signal is a bias RF signal with an effective value of 2 kW of power, or a bias DC signal including a sequence of negative-polarity DC pulses with an effective value of less than 2 kV of voltage.

21. A plasma processing method, which is a plasma processing method performed in a plasma processing device, The plasma processing apparatus includes a chamber and a substrate support portion disposed in the chamber. The plasma treatment method comprises the following steps: Step (a), preparing a substrate, the substrate comprising a first silicon-containing film, a carbon-containing film on the first silicon-containing film, a second silicon-containing film on the carbon-containing film, and a resist film on the second silicon-containing film, wherein: The resist film includes an opening pattern having an opening width of 30 nm or less; Step (b), etching the second silicon-containing film through the resist film to form a first recess in the second silicon-containing film; step (c), etching the carbon-containing film through the first recess to form a second recess in the carbon-containing film; and step (d), etching the first silicon-containing film through the second recess, wherein, in the step (b), the step (c) and the step (d), a bias signal having an effective value of less than 2 kW is supplied to the substrate support portion; The step (b) comprises the following steps: Step (b-1), supplying a processing gas containing at least hydrogen and fluorine; and In step (b-2), a plasma containing hydrogen fluoride species is generated from the processing gas.

22. The plasma processing method according to claim 21, wherein: The substrate further comprises a base film under the first silicon-containing film, The step (d) comprises the following steps: Step (d-1), etching the first silicon-containing film using plasma generated from a fourth processing gas containing fluorine to form a third recess in the first silicon-containing film, wherein the opening size of the third recess on the carbon-containing film side is larger than the opening size on the base film side; and In step (d-2), the opening size of the third recessed portion on the base film side is enlarged by using plasma generated from a fifth process gas including a hydrogen fluoride gas and a carbon-containing gas.

23. The plasma processing method according to claim 22, wherein: The fourth process gas includes at least one of hydrogen fluoride gas and fluorocarbon gas, The carbon-containing gas includes a hydrofluorocarbon gas having a carbon number of 3 or more.

24. The plasma processing method according to claim 22, wherein: Plasma is continuously generated during two or more consecutive steps among the step (b), the step (c), and the step (d).

25. The plasma processing method according to claim 22, wherein: The plasma processing device is an inductively coupled plasma processing device, The steps (a), (b), (c), and (d) are performed in the same chamber.

26. A plasma processing apparatus comprising a chamber, a gas supply unit, a plasma generating unit, a substrate supporting unit disposed in the chamber, and a control unit, wherein: The control unit performs the following control: Control (a), preparing a substrate on a substrate support portion, the substrate including a silicon-containing film as an inorganic film containing silicon, and a mask on the silicon-containing film, the mask including an opening pattern having an opening width of 30 nm or less; as well as controlling (b) to generate plasma in the chamber and to etch the silicon-containing film through the mask to form a recess in the silicon-containing film, Wherein, in the control (b), the control unit performs the following control: Control (b-1) to supply a processing gas containing hydrogen fluoride into the chamber; controlling (b-2) to generate plasma from the process gas in the chamber; as well as Control (b-3) to supply a bias signal to the substrate support portion, wherein the bias signal is a bias RF signal with an effective value of power less than 2kW, or a bias DC signal containing a sequence of negative-polarity DC pulses with an effective value of voltage less than 2kV.

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