Etching method and plasma treatment system

Abstract

This etching method comprises: (a) a step for preparing a substrate, wherein the substrate includes a film to be etched, a boron-containing film provided on the film to be etched, and a mask provided on the boron-containing film, and the mask includes a side wall defining at least one first opening exposing the boron-containing film; (b) a step for forming, on an upper surface of the mask, a deposition film containing a metal and / or a semiconductor element; (c) a step for etching, through the first opening, the boron-containing film by means of plasma generated from a first treatment gas; and (d) a step for etching, through the first opening, the film to be etched by means of plasma generated from a second treatment gas.

Description

Etching method and plasma processing system

[0001] SUMMARY Exemplary embodiments of the present disclosure relate to an etching method and a plasma processing system.

[0002] Japanese Patent Application Laid-Open No. 2003-124222 discloses a technique for suppressing mask loss that occurs during etching of high aspect ratio holes.

[0003] US Patent Application Publication No. 2018 / 0233357

[0004] The present disclosure provides a technique for controlling the shape of a mask to etch a film to be etched.

[0005] In one exemplary embodiment of the present disclosure, there is provided an etching method including: (a) preparing a substrate, the substrate including a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having a sidewall defining at least one first opening exposing the boron-containing film; (b) forming a deposited film including a metal and / or a semiconductor element on an upper surface of the mask; (c) etching the boron-containing film with plasma generated from a first process gas through the first opening; and (d) etching the film to be etched with plasma generated from a second process gas through the first opening.

[0006] According to one exemplary embodiment of the present disclosure, a technique for etching a film to be etched by controlling the shape of a mask can be provided.

[0007] FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system. FIG. 2 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. FIG. 3 is a flowchart showing the etching method. FIG. 4 is a diagram showing an example of the cross-sectional structure of a substrate W prepared in process ST1. FIG. 5 is a diagram showing an example of the cross-sectional structure of a substrate W after process ST2 has been performed. FIG. 6 is a diagram showing an example of the cross-sectional structure of a substrate W during process ST4 after process ST3 has been performed. FIG. 7 is a flowchart showing a modified example of the etching method. FIG. 8 is a diagram showing an example of the cross-sectional structure of a substrate W after process ST2A has been performed. FIG. 9 is a diagram showing an example of the cross-sectional structure of a substrate W during process ST4 after process ST2A has been performed and then process ST2 and process ST3 have been performed. FIG. 10 is a flowchart showing an example of process ST1. FIG. 11 is a diagram showing an example of the cross-sectional structure of a substrate W after process ST12 has been performed.

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, there is provided an etching method including: (a) preparing a substrate, the substrate including a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) forming a deposited film including a metal and / or a semiconductor element on an upper surface of the mask; (c) etching the boron-containing film with plasma generated from a first process gas through the first opening; and (d) etching the film to be etched with plasma generated from a second process gas through the first opening.

[0010] In one exemplary embodiment, in the step (b), the deposited film (i) is not formed on the boron-containing film, or (ii) is also formed on the boron-containing film to a thickness thinner than that formed on the mask.

[0011] In one exemplary embodiment, the etching method further includes, between the step (a) and the step (b), a step of forming a boron-containing deposition film containing boron on the sidewall of the mask.

[0012] In one exemplary embodiment, the boron-containing deposited film is formed by sputtering the boron-containing film.

[0013] In one exemplary embodiment, in step (b), the deposition film is (i) not formed on the sidewalls of the mask, or (ii) formed thinner on the sidewalls of the mask than on the top surface of the mask.

[0014] In one exemplary embodiment, in the step (b), the deposition film is formed on the upper surface of the mask and on the sidewalls of the mask.

[0015] In one exemplary embodiment, the film to be etched includes at least one selected from the group consisting of a silicon-containing film, a carbon-containing film, and a metal-containing film.

[0016] In one exemplary embodiment, the boron-containing film includes at least one selected from the group consisting of a boron film, a boron nitride film, a boron oxide film, and a boron carbide film.

[0017] In one exemplary embodiment, the mask is a metal-containing resist.

[0018] In one exemplary embodiment, the mask is a chemically amplified resist.

[0019] In one exemplary embodiment, the deposited film comprises at least one selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge.

[0020] In one exemplary embodiment, the step (b) includes the steps of: (b1) exposing the substrate to a precursor gas containing a metal; and (b2) exposing the substrate to a reactive gas or a plasma generated from the reactive gas.

[0021] In one exemplary embodiment, the precursor gas comprises at least one halide selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge.

[0022] In one exemplary embodiment, the precursor gas comprises a halide of at least one metal selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, and Zn, and a halide of at least one semiconductor element selected from the group consisting of Si and Ge.

[0023] In one exemplary embodiment, the precursor gas further comprises an element different from the metal and the semiconductor element.

[0024] In one exemplary embodiment, the reaction gas is NH ３ , N ２ , N ２ H ４ , N ２ H ２ , O ２ , O ３ , H ２ O, NO, N ２ O, H ２ , H ２ S, CH ４ , and SiH ４ The compound includes at least one selected from the group consisting of:

[0025] In one exemplary embodiment, the first process gas comprises at least one selected from the group consisting of a fluorine-containing gas, a chlorine-containing gas, a bromine-containing gas, a carbon-containing gas, and a hydrogen-containing gas.

[0026] In one exemplary embodiment, the first process gas and the second process gas are fluorine-containing gases.

[0027] In one exemplary embodiment, the step (a) includes: (a1) preparing a substrate, the substrate including the etching target film, the boron-containing film, a first film on the boron-containing film, and a second film on the first film, the second film including a sidewall defining at least one second opening exposing the first film; and (a2) etching the first film through the second opening to form the first opening penetrating the first film and the second film, thereby forming the mask.

[0028] In one exemplary embodiment, steps (b) and (c) are performed in separate chambers.

[0029] In one exemplary embodiment, steps (a), (b) and (c) are performed in the same chamber.

[0030] In one exemplary embodiment, there is provided an etching method including: (a) preparing a substrate, the substrate including a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) forming a deposited film including a metal and / or a semiconductor element on an upper surface of the mask; and (c) etching the boron-containing film through the first opening with plasma generated from a first process gas.

[0031] In one exemplary embodiment, there is provided a plasma processing system comprising: a chamber; a substrate support disposed within the chamber; and a controller, wherein the controller is configured to execute the following controls: (a) control to prepare a substrate, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) control to form a deposition film including a metal and / or a semiconductor element on an upper surface of the mask; and (c) control to etch the boron-containing film with plasma generated from a first process gas through the first opening.

[0032] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are designated by the same reference numerals, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships, such as up, down, left, and right, will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0033] <Configuration Example of Plasma Processing System> FIG. 1 is a diagram illustrating a configuration example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0034] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0035] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0036] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0037] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0038] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0039] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Furthermore, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0040] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0041] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0042] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0043] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0044] 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 lower electrode and / or at least one upper electrode. This generates a plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0045] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0046] The second RF generator 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0047] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to the at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to the at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0048] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0049] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0050] <Example of Etching Method> FIG. 3 is a flowchart showing an etching method (hereinafter also referred to as "this etching method") according to an illustrative embodiment. This etching method includes a step ST1 of preparing a substrate, a step ST2 of forming a deposited film, and a step ST3 of etching a boron-containing film. In one embodiment, this etching method may further include a step ST4 of etching a film to be etched after step ST3. Each step may be performed using one of the above-described plasma processing systems (see FIGS. 1 and 2), or may be performed using two or more of these plasma processing systems. For example, this etching method may be performed in the plasma processing system (see FIG. 1). The following description will be given taking as an example a case where the controller 2 controls each component of the plasma processing apparatus 1 to perform this etching method on a substrate W.

[0051] (Process ST1: Preparation of Substrate) In process ST1, a substrate W is prepared. The substrate W includes a film to be etched, a boron-containing film disposed on the film to be etched, and a mask disposed on the boron-containing film. The mask includes a sidewall that defines at least one first opening on the boron-containing film. The substrate W may be used for manufacturing semiconductor devices. The semiconductor devices include, for example, memory devices such as DRAMs and 3D-NAND flash memories, and logic devices.

[0052] 4 is a diagram showing an example of a cross-sectional structure of the substrate W prepared in step ST1. As illustrated in Fig. 4, the substrate W may be configured by laminating an etching target film F1, a boron-containing film F2, and a mask F3 in this order on an arbitrary base film UF.

[0053] The base film UF is, for example, a silicon wafer, an organic film formed on a silicon wafer, a dielectric film, a metal film, a semiconductor film, etc. The base film UF may be configured by stacking a plurality of films.

[0054] The etching target film F1 may include, for example, at least one selected from the group consisting of a silicon-containing film, a carbon-containing film, and a metal-containing film. Examples of silicon-containing films include spin-on-glass (SOG) films, Si-containing antireflective coatings (SiARC), silicon oxide films, silicon nitride films, silicon oxynitride films, silicon carbide films, silicon carbonitride films, and polycrystalline silicon films. Examples of carbon-containing films include spin-on-carbon (SOC) films and amorphous carbon films. Examples of metal-containing films include titanium-containing films, tungsten-containing films, ruthenium-containing films, zirconium-containing films, aluminum-containing films, and hafnium-containing films. Examples of titanium-containing films include titanium oxide films and titanium nitride films. Examples of tungsten-containing films include tungsten films, tungsten carbide films, and tungsten silicide films. Examples of ruthenium-containing films include ruthenium films. Examples of zirconium-containing films include zirconium oxide films. Examples of aluminum-containing films include aluminum oxide films. Examples of hafnium-containing films include hafnium oxide films. The etching target film F1 and the underlayer film UF constituting the substrate W may each be formed by a CVD method, an atomic layer deposition (hereinafter referred to as an "ALD method"), a spin coating method, or the like. The etching target film F1 and the underlayer film UF may each be a flat film, or may be a film having irregularities.

[0055] The boron content in the boron-containing film F2 may be, for example, 20 atomic % to 100 atomic %, or 40 atomic % to 100 atomic %. The boron-containing film F2 may be, for example, a B film, a BN film, a BNC film, a BO film, a BNOC film, a SiBN film, a SiBCN film, or a SiOBN film. Here, the BN film refers to a film containing boron (B) and nitrogen (N), and the atomic ratio of B to N in the BN film is not limited to 1:1. Films other than BN, such as BNC films, also contain the respective elements, and the stoichiometric ratio is not particularly limited. In one embodiment, the boron-containing film F2 may contain at least one selected from the group consisting of a boron film, a boron nitride film, a boron oxide film, and a boron carbide film.

[0056] The boron-containing film F2 may be formed by various methods such as ALD and CVD. In the case of ALD, the boron-containing film F2 may be formed by supplying a boron-containing gas, allowing the boron-containing gas to be adsorbed on the surface of the film to be etched, and then supplying a reactive gas and reacting the boron-containing gas with the reactive gas, and performing this cycle one or more times. The boron-containing gas and the reactive gas may be supplied together with a dilution gas. After supplying the boron-containing gas, excess boron-containing gas may be purged before supplying the reactive gas. The boron-containing gas may be, for example, trisdimethylaminoborane (TDMAB:C ６ H １８ BN ３ ), diborane (B ２ H ６ ), boron trichloride (BCl ３ ), boron trifluoride (BF ３ ), trisethylmethylaminoborane (C ９ H ２４ BN ３ ), trimethylborane (C ３ H ９ B), or triethylborane (C ６ H １５ B), cyclotriborazane (B ３ N ３ H ６ Examples of the reactive gas include a nitrogen-containing gas, an oxygen-containing gas, and a reducing gas. Examples of the nitrogen-containing gas include NH ３ , N ２ , N ２ H ４ or N ２ H ２ Examples of oxygen-containing gases include O ２ , O ３ , H ２ O, NO or N ２ Examples of the reducing gas include H ２ , H ２ S, CH ４ , SiH ４ Examples of dilution gases include Ar and N ２In the case of the CVD method, for example, the boron-containing gas and the reactive gas described above may be used to form the boron-containing film F2 on the etching target film F1 by plasma CVD, thermal CVD, or the like.

[0057] The mask F3 is formed on the boron-containing film F2 and includes a sidewall F3a that defines at least one first opening OP1. In one embodiment, the mask F3 may be a photoresist. In one embodiment, the mask F3 may be a photoresist exposed to extreme ultraviolet light (hereinafter referred to as "EUV"). In one embodiment, the mask F3 may be a metal-containing resist. In one embodiment, the metal contained in the metal-containing resist may be at least one selected from the group consisting of Sn, Hf, and Ti. In one embodiment, the metal-containing resist may contain Sn. As an example, the metal-containing resist may contain tin oxide (Sn—O bond) or tin hydroxide (Sn—OH bond). As an example, the metal-containing resist may be exposed to EUV. In one embodiment, the mask F3 may be a chemically amplified resist (hereinafter referred to as "CAR"), and as an example, the CAR may be exposed by EUV.

[0058] The first opening OP1 may have any shape in a plan view of the substrate W, i.e., when the substrate W is viewed from top to bottom in FIG. 4 . The shape may be, for example, a circle, an ellipse, a rectangle, a line, or a combination of one or more of these. The mask F3 may have multiple sidewalls that define multiple first openings OP1. The multiple first openings OP1 may each have a linear shape and be arranged at regular intervals to form a line-and-space pattern. Alternatively, the multiple first openings OP1 may each have a hole shape and form an array pattern. In one embodiment, the first opening OP1 may be formed by lithography. For example, the first opening OP1 may be formed by exposing and developing a photoresist formed on the boron-containing film F2. When an EUV resist is used as the photoresist, the exposure may be EUV exposure using an EUV exposure apparatus. Furthermore, the development may be dry development or wet development.

[0059] In step ST1, the substrate W may be prepared in a plasma processing chamber 10 (hereinafter also referred to as "chamber 10"). In one embodiment, the substrate W is carried into the chamber 10 by a transport arm, placed on a substrate support 11 by a lifter, and held by suction on the substrate support 11, for example, as shown in FIG.

[0060] After the substrate W is placed on the substrate support 11, the temperature of the substrate support 11 may be adjusted to a set temperature by a temperature control module. The set temperature may be, for example, a temperature of 60°C or less (e.g., room temperature). In one example, adjusting or maintaining the temperature of the substrate support 11 includes adjusting or maintaining the temperature of the heat transfer fluid flowing through the flow path 1110a at a set temperature or a temperature different from the set temperature. In one example, adjusting or maintaining the temperature of the substrate support 11 includes controlling the pressure of a heat transfer gas (e.g., He) between the electrostatic chuck 1111 and the back surface of the substrate W. Note that the timing at which the heat transfer fluid starts flowing through the flow path 1110a may be before, after, or simultaneously with the substrate W being placed on the substrate support 11. In addition, in this etching method, the temperature of the substrate support 11 may be adjusted to the set temperature before step ST1. That is, the substrate W may be prepared on the substrate support 11 after the temperature of the substrate support 11 is adjusted to the set temperature. In the subsequent steps of this etching method, the temperature of the substrate support 11 may be maintained at the set temperature adjusted in step ST1.

[0061] In one embodiment, the substrate W may be controlled to a set temperature instead of controlling the substrate support 11 to a set temperature. Controlling the temperature of the substrate W to a set temperature includes setting the temperature of the substrate support 11, the heat transfer fluid flowing through the flow path 1110a, and / or the heater temperature to the set temperature or to a temperature different from the set temperature.

[0062] (Step ST2: Formation of Deposited Film) Next, in step ST2, a deposited film DF is formed on the substrate W. In one embodiment, the deposited film DF contains a metal and / or a semiconductor element. The deposited film DF may contain at least one element selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge. The deposited film DF may contain at least one metal element selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, and Zn, and at least one semiconductor element selected from the group consisting of Si and Ge. Furthermore, the deposited film DF may further contain, in addition to the above-mentioned metal and semiconductor elements, other elements different from these metal and semiconductor elements. In step ST2, the deposited film DF is disposed at least on the mask F3.

[0063] FIG. 5 shows an example of the cross-sectional structure of a substrate W on which a deposited film DF is formed. In one embodiment, the deposited film DF is selectively or preferentially formed on the upper surface F3b of the mask F3. The deposited film DF is not formed on the boron-containing film F2, or is formed thinner on the boron-containing film F2 than on the upper surface F3b of the mask F3. This is thought to be because the boron-containing film F2 inhibits the formation of the deposited film DF. In one embodiment, the deposited film DF may be formed on the side surface F3a of the mask F3 as well as the upper surface F3b of the mask F3. The deposited film DF may be formed conformally on the mask F3. That is, the thickness of the deposited film DF formed on the sidewall F3a may be the same as the thickness of the deposited film DF formed on the upper surface F3b. Alternatively, the deposited film DF may be formed subconformally on the mask F3. For example, the thickness of the deposited film DF formed on the sidewall F3a may be different from the thickness of the deposited film DF formed on the upper surface F3b. The thickness of the deposition film DF formed on the sidewall F3a can be adjusted by, for example, the amount of the second boron-containing film deposited in step ST2A, which will be described later.

[0064] In one embodiment, the deposited film DF can function as a protective film that protects the mask F3 during the etching process in step ST3 and / or step ST4, which will be described later. According to one embodiment, the opening dimensions of the first opening OP1 can be adjusted to a desired dimension by adjusting the thickness (deposition amount) of the deposited film DF formed on the sidewall F3a. Furthermore, according to one embodiment, the mask F3 can be corrected to a desired shape by adjusting the thickness (deposition amount) of the deposited film DF formed on the sidewall F3a. For example, when the mask F3 is an EUV resist (EUV exposure is performed when forming the mask F3), reducing the exposure amount (dose) to reduce power consumption during EUV exposure can cause shape abnormalities in the mask F3 after development. For example, the opening dimensions of the first opening OP1 can be larger than the desired dimensions. In this regard, according to one embodiment, forming the deposited film DF on the sidewall F3a can correct the mask F3 to a desired shape, thereby mitigating or eliminating such shape abnormalities. For example, the opening dimensions of the first opening OP1 can be reduced to a desired dimension.

[0065] In one embodiment, the deposited film DF may be formed by an ALD method. For example, step ST2 may include exposing the substrate W to a precursor gas containing a metal, and exposing the substrate W to a reactive gas or plasma generated from the reactive gas. In one embodiment, the precursor gas may include at least one selected from the group consisting of Ti halide, W halide, V halide, Al halide, Mo halide, Sn halide, Hf halide, Ta halide, Nb halide, Zr halide, In halide, Ga halide, Zn halide, Si halide, Ge halide, and Sb halide. In one embodiment, the reactive gas may include NH ３ , N ２ , N ２ H ４ , N ２ H ２ , O ２ , O ３ , H ２ O, NO, N ２ O, H ２ , H ２ S, CH ４ , and SiH ４The reactive gas may include, for example, a nitrogen-containing gas, an oxygen-containing gas, a reducing gas, etc. The nitrogen-containing gas may include, for example, NH ３ , N ２ , N ２ H ４ or N ２ H ２ Examples of oxygen-containing gases include O ２ , O ３ , H ２ O, NO or N ２ Examples of the reducing gas include H ２ , H ２ S, CH ４ , SiH ４ Examples of dilution gases include Ar and N ２ etc.

[0066] The precursor gas contains, for example, a halogen and an element X other than a halogen. Examples of halogen include fluorine, chlorine, bromine, and iodine. Examples of the element X include a metal element, and examples of the metal element include a transition metal element. Examples of the element X include Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, and Sb. Specific examples of the precursor gas include TiCl ４ Gas, WCl ６ Gas, WF ６ Gas, VCl ４ Gas, AlCl ３ Gas, MoCl ５ Gas, SnCl ４ Gas, HfCl ４ Gas, TaCl ５ Gas, NbCl ５ Gas, ZrCl ４ Gas, InCl ３ Gas, GaCl ３ gas or SbCl ３ Gas is one example.

[0067] The element X may be a semiconductor element, specifically Si or Ge. As an example, the precursor gas may be a silicon halide gas or a germanium halide gas. Specific examples of silicon halide gas include SiCl. ４ Gas, SiHCl ３ Gas, SiH ２ Cl ２ Gas, SiH ３ Cl gas, Si ２ Cl ６ Gas, Si ２ HCl ５ Gas, Si ２ Cl ３ CH ３ Gas, SiCl ３ CCl ３ Gas, SiCl ３ CH ３ gas, or SiH ２ I ２ Specific examples of germanium halide gas include GeCl ４ Gas, etc.

[0068] The precursor gas may be supplied together with a diluent gas, such as Ar gas or N ２ It's gas.

[0069] In one embodiment, the reactive gas may react with an element X that may be contained in the precursor gas to form a deposited film DF containing the element X. Examples of the reactive gas include an oxygen-containing gas, a nitrogen-containing gas, and a hydrogen-containing gas. Examples of the oxygen-containing gas include a gas that contains oxygen and forms an oxide film of the element X. Specific examples of the oxygen-containing gas include O ２ Gas, O ３ Gas, CO ２ Gas, N ２ O gas, NO gas, or H ２ Examples of the nitrogen-containing gas include a gas containing nitrogen and forming a nitride film of element X. Specific examples of the nitrogen-containing gas include NH ３ Gas or N ２ H ４Examples of the hydrogen-containing gas include a gas that contains hydrogen and forms a film (for example, a metal film or a semiconductor film) containing element X as a main component. Specific examples of the hydrogen-containing gas include H ２ Gas or H ２ S gas is an example.

[0070] In one embodiment, the reactive gas may be supplied with a diluent gas, such as Ar gas or N ２ The reactive gas may be plasmatized. Note that the reactive gas may not be necessary depending on the material of the deposition film DF.

[0071] In one embodiment, the deposited film DF may be formed by a CVD method. In one embodiment, a precursor gas that can be used in the CVD method can be appropriately selected from those exemplified as precursor gases that can be used in the ALD method.

[0072] As described above, when the deposited film DF is formed by the ALD method or the CVD method, metal chlorides or the like can be used in each method. The boron-containing film F2 containing boron tends to inhibit the adsorption of metal chlorides or the like, and the formation of the deposited film DF on the boron-containing film F2 by the ALD method or the CVD method tends to be further inhibited. Therefore, when the ALD method or the CVD method is employed, the selective formation of the deposited film DF on the mask F3 tends to be further promoted.

[0073] (Step ST3: Etching of Boron-Containing Film) In step ST3, the boron-containing film F2 is etched. In step ST3, the boron-containing film F2 is etched by plasma generated from a first process gas using the mask F3 on which the deposition film DF is formed as a mask. Step ST3 includes supplying the first process gas to the chamber 10 and generating plasma from the first process gas.

[0074] First, a first process gas is supplied into the chamber 10. The first process gas may be supplied into the chamber 10 from the gas supply unit 20 via the gas inlet 13c of the shower head 13, for example. In one embodiment, the first process gas may include at least one gas selected from the group consisting of a fluorine-containing gas, a chlorine-containing gas, a bromine-containing gas, a carbon-containing gas, and a hydrogen-containing gas. In one embodiment, the first process gas may include a fluorine-containing gas.

[0075] Next, plasma is generated from the first process gas in the chamber 10. For example, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the shower head 13. When a high-frequency electric field is generated between the shower head 13 and the substrate support 11, plasma is generated from the first process gas in the chamber 10. At this time, the mask F3 functions as a mask, and the portion of the boron-containing film F2 exposed to the first opening OP1 is etched by activated species in the plasma, forming a recess. As the etching progresses, the bottom of the recess reaches the etching target film F1, and the etching target film F1 is exposed to the first opening OP1. During etching, the deposited film DF can function as a protective film for the mask F3.

[0076] In one embodiment, a bias signal may be supplied to the lower electrode of the substrate support 11. In this case, a bias potential is generated between the plasma and the substrate W, and ions in the plasma are attracted to the substrate W, thereby promoting etching. The bias signal may be a bias DC signal supplied from the DC generator 32a, or a bias RF signal supplied from the second RF generator 31b. In one embodiment, a bias signal does not need to be supplied to the lower electrode of the substrate support 11.

[0077] (Step ST4: Etching of Etching Target Film) In one embodiment, the etching method may include step ST4 of etching the etching target film after step ST3. In step ST4, the etching target film F1 is etched by plasma generated from a second process gas using the mask F3 on which the deposition film DF is formed as a mask. Step ST4 includes supplying the second process gas to the chamber 10 and generating plasma from the second process gas.

[0078] First, the second process gas is supplied into the chamber 10. The second process gas may be supplied into the chamber 10 from the gas supply unit 20 via the gas inlet 13c of the shower head 13, for example.

[0079] The second process gas may be appropriately selected depending on the type of film to be etched. For example, when the film to be etched is a silicon-containing film, the second process gas may contain a fluorine-containing gas. The fluorine-containing gas may contain at least one gas selected from the group consisting of hydrogen fluoride (HF) gas, a CF-based gas, and a CHF-based gas. In addition to the fluorine-containing gas, the second process gas may contain at least one gas selected from the group consisting of a phosphorus-containing gas, a metal-containing gas, a halogen-containing gas other than fluorine, and an oxygen-containing gas. In one example, the phosphorus-containing gas is a halogenated phosphorus gas. In one example, the metal-containing gas is WF ２ Gas, WF ４ Gas, WF ５ Gas, WF ６ Gas, WCl ２ Gas, WCl ４ Gas, WCl ５ Gas, WCl ６ Gas, MoF ４ Gas, MoF ６ Gas, MoCl ６ Gas, TiCl ４ In one example, the halogen-containing gas other than fluorine is Cl ２ In one example, the oxygen-containing gas is O ２ , CO, CO ２ , H ２ O and H ２ O ２At least one gas selected from the group consisting of:

[0080] In one embodiment, the second process gas is composed of a gas different from the first process gas, or the second process gas is composed of the same gas as the first process gas. In this case, step ST4 may be performed consecutively from step ST3.

[0081] Next, plasma is generated from the second process gas in the chamber 10. For example, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the shower head 13. When a high-frequency electric field is generated between the shower head 13 and the substrate support 11, plasma is generated from the second process gas in the chamber 10. At this time, the mask F3 functions as a mask, and the portion of the film to be etched that is exposed to the opening OP is etched by activated species in the plasma. During etching, the deposited film DF can function as a protective film for the mask F3.

[0082] FIG. 6 shows an example of the cross-sectional structure of the substrate W during the execution of step ST4. In the example shown in FIG. 6, the deposited film DF and the boron-containing film F2 disposed under the mask F3 remain, while the boron-containing film F2 is removed by etching at a position corresponding to the first opening OP1 of the mask. Also, in the example shown in FIG. 6, the etching target film F1 is also removed by etching at a position corresponding to the boron-containing film F2 removed in step ST3. That is, a recess having a shape corresponding to the opening OP is formed in the etching target film F1. As described above, the deposited film DF can function as a protective film for the mask when etching the boron-containing film F2 and the etching target film F1. This can improve the etching selectivity.

[0083] In one embodiment, steps ST1, ST2, and ST3 may be performed in the same chamber. Also, in one embodiment, steps ST1, ST2, ST3, and ST4 may be performed in the same chamber. Furthermore, in one embodiment, at least steps ST2 and ST3 may be performed in different chambers.

[0084] According to the above embodiment, it is possible to provide a technique for selectively forming a film on a substrate.

[0085] <Modification> FIG. 7 is a flowchart showing a modification of the present etching method. As shown in FIG. 7 , the etching method of this modification includes step ST1 of preparing a substrate, step ST2A of forming a boron-containing film, step ST2 of forming a deposited film, step ST3 of etching, and step ST4 of etching. Steps ST1, ST2, ST3, and ST4 in the etching method of this modification can be performed in the same manner as steps ST1, ST2, ST3, and ST4 described above with respect to the present etching method. Step ST2A can be performed between steps ST1 and ST2. As illustrated in FIG. 8 , by performing step ST2A, a boron-containing film (second boron-containing film) F4 can be formed on the sidewall F3a of the mask F3. In one embodiment, the second boron-containing film F4 may be formed by sputtering the boron-containing film (first boron-containing film) F2. In one example, noble gases such as Ar, He, and Kr can be used to sputter the first boron-containing film F2.

[0086] In the etching method of this modified example, step ST2 is performed after step ST2A. In one embodiment, the deposited film DF is selectively or preferentially formed on the upper surface F3b of the mask F3. The deposited film DF is not formed on the first boron-containing film F2 and the second boron-containing film F4, or is formed thinner on the first boron-containing film F2 and the second boron-containing film F4 than on the upper surface F3b of the mask F3. This is thought to be because, as described above, the first boron-containing film F2 and the second boron-containing film F4 inhibit the formation of the deposited film DF. FIG. 9 shows an example of the cross-sectional structure of the substrate W after step ST2A and step ST2 are performed. In the example shown in FIG. 9, the deposited film DF is not formed on the first boron-containing film F2 (on the surface exposed to the first opening OP1), and is not formed on the second boron-containing film F4. In other words, in the example of FIG. 9 , the deposited film DF is not formed on the sidewall F3a of the mask F3. Thus, according to this modification, the formation of the deposited film DF on the first boron-containing film F2 and the sidewall F3a of the mask F3 is inhibited, thereby suppressing fluctuations in the opening dimensions of the first opening OP1 in step ST2. Furthermore, in one embodiment, the deposition amount (thickness) of the deposited film DF can be adjusted by adjusting the deposition amount of the second boron-containing film F4. For example, the deposition of the deposited film DF in step ST2 can be performed by an ALD method or a CVD method, during which the second boron-containing film F4 can be exposed to plasma. The thickness of the second boron-containing film F4 exposed to plasma decreases and may eventually disappear. When the second boron-containing film F4 disappears in this manner, a deposited film DF can gradually form on the sidewall F3a after the second boron-containing film F4 disappears. In this way, the deposition amount (thickness) of the deposition film DF can be adjusted by adjusting the deposition amount of the second boron-containing film F4. In one example, when the deposition amount of the second boron-containing film F4 is reduced, the deposition amount (thickness) of the deposition film DF increases, which can reduce the opening dimension of the first opening OP1.

[0087] In the etching method of this modification, steps ST2 and ST3 can be performed after step ST2A, and step ST4 can also be performed after step ST3. FIG. 10 shows an example of a cross-sectional structure of a substrate W during step ST4 after step ST2A, step ST2, and step ST3. In the example shown in FIG. 10, the deposited film DF and the boron-containing film F2 disposed under the mask F3 remain, while the boron-containing film F2 is removed by etching at a position corresponding to the first opening OP1. Also, in the example shown in FIG. 10, the etching target film F1 is also removed by etching at a position corresponding to the boron-containing film F2 removed in step ST3. That is, a recess having a shape corresponding to the first opening OP1 is formed in the etching target film F1. As described above, the deposited film DF can function as a protective film for the mask F3 during etching of the boron-containing film F2 and film F1. Furthermore, as described above, in this modification, the deposited film DF tends to be formed selectively on the upper surface F3b of the mask F3 relative to the sidewall F3a of the mask F3, so that the opening size of the opening OP can be controlled, and therefore, the etching selectivity can be improved while controlling the opening size of the opening OP.

[0088] 11 is a flowchart showing another modification of the present etching method. As shown in FIG. 11, the etching method of this modification includes, in step ST1, step ST11 of preparing a substrate and step ST12 of forming a mask. In the etching method of this modification, after steps ST11 and ST12, steps ST2, ST3, and ST4 described above in relation to the present etching method can be performed in the same manner.

[0089] 12 , in step ST11, a substrate W is prepared. In the example of FIG. 12 , the substrate W includes an etching target film F1 on an undercoat film UF, a boron-containing film F2 disposed on the etching target film F1, a first film F5 disposed on the boron-containing film F2, and a second film F6 disposed on the first film F5. The second film F6 includes a sidewall F6a defining at least one second opening OP2 exposing the first film F5. In one embodiment, the second opening OP2 may be formed by lithography. As an example, the second opening OP2 may be formed by EUV exposure. In another embodiment, the second opening OP2 may be formed by etching. The first film F5 and the second film F6 may each independently include, for example, at least one selected from the group consisting of a silicon-containing film and a carbon-containing film. Examples of silicon-containing films include spin-on-glass (SOG) films, Si-containing antireflective coatings (SiARC), silicon oxide films, silicon nitride films, silicon oxynitride films, silicon carbide films, silicon carbonitride films, and polycrystalline silicon films. Examples of carbon-containing films include spin-on carbon (SOC) films and amorphous carbon films. As illustrated in FIG. 13 , in step ST11, a mask F3 is formed. In the example of FIG. 13 , the mask F3 is formed by etching the first film F5 through the second opening OP2 to form a first opening OP1 penetrating the first film F5 and the second film F6. During etching, the second film F6 can function as a protective film for the first film F5. The etching method of this modified example allows for control of the pattern shape of the mask F3 (the shape of the first opening OP1).

[0090] Embodiments of the present disclosure further include the following aspects.

[0091] (Supplementary Note 1) An etching method comprising: (a) preparing a substrate, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) forming a deposited film containing a metal and / or a semiconductor element on an upper surface of the mask; (c) etching the boron-containing film with plasma generated from a first process gas through the first opening; and (d) etching the film to be etched with plasma generated from a second process gas through the first opening.

[0092] (Supplementary Note 2) The etching method according to Supplementary Note 1, wherein in (b), the deposited film (i) is not formed on the boron-containing film, or (ii) is formed on the boron-containing film to a thickness thinner than that formed on the upper surface of the mask.

[0093] (Supplementary Note 3) The etching method according to Supplementary Note 1 or Supplementary Note 2, further comprising the step of forming a boron-containing deposition film on the sidewall of the mask between the steps (a) and (b).

[0094] (Supplementary Note 4) The etching method according to Supplementary Note 3, wherein the boron-containing deposition film is formed by sputtering the boron-containing film.

[0095] (Supplementary Note 5) The etching method according to Supplementary Note 3 or Supplementary Note 4, wherein in (b), the deposited film (i) is not formed on the sidewall of the mask, or (ii) is formed thinner on the sidewall of the mask than on the top surface of the mask.

[0096] (Supplementary Note 6) The etching method according to any one of Supplementary Notes 1 to 5, wherein in (b), the deposited film is formed on the upper surface of the mask and on the sidewalls of the mask.

[0097] (Supplementary Note 7) The etching method according to any one of Supplementary Note 1 to Supplementary Note 6, wherein the etching target film includes at least one film selected from the group consisting of a silicon-containing film, a carbon-containing film, and a metal-containing film.

[0098] (Supplementary Note 8) The etching method according to any one of Supplementary Note 1 to Supplementary Note 7, wherein the boron-containing film includes at least one selected from the group consisting of a boron film, a boron nitride film, a boron oxide film, and a boron carbide film.

[0099] (Supplementary Note 9) The etching method according to any one of Supplementary Note 1 to Supplementary Note 8, wherein the mask is a metal-containing resist.

[0100] (Supplementary Note 10) The etching method according to any one of Supplementary Note 1 to Supplementary Note 9, wherein the mask is a chemically amplified resist.

[0101] (Supplementary Note 11) The etching method according to any one of Supplementary Note 1 to Supplementary Note 10, wherein the deposited film contains at least one element selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge.

[0102] (Supplementary Note 12) The etching method according to any one of Supplementary Note 1 to Supplementary Note 11, wherein (b) comprises: (b1) exposing the substrate to a precursor gas containing a metal; and (b2) exposing the substrate to a reactive gas or plasma generated from the reactive gas.

[0103] (Supplementary Note 13) The etching method according to Supplementary Note 12, wherein the precursor gas contains at least one halide selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge.

[0104] (Supplementary Note 14) The etching method according to Supplementary Note 12 or Supplementary Note 13, wherein the precursor gas contains a halide of at least one metal selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, and Zn, and a halide of at least one semiconductor element selected from the group consisting of Si and Ge.

[0105] (Supplementary Note 15) The etching method according to any one of Supplementary Note 12 to Supplementary Note 14, wherein the precursor gas further contains an element different from the metal and the semiconductor element.

[0106] (Supplementary Note 16) The reactive gas is NH３ , N ２ , N ２ H ４ , N ２ H ２ , O ２ , O ３ , H ２ O, NO, N ２ O, H ２ , H ２ S, CH ４ , and SiH ４ 16. The etching method according to any one of claims 12 to 15, comprising at least one selected from the group consisting of:

[0107] (Supplementary Note 17) The etching method according to any one of Supplementary Note 1 to Supplementary Note 16, wherein the first process gas contains at least one gas selected from the group consisting of a fluorine-containing gas, a chlorine-containing gas, a bromine-containing gas, a carbon-containing gas, and a hydrogen-containing gas.

[0108] (Supplementary Note 18) The etching method according to any one of Supplementary Note 1 to Supplementary Note 17, wherein the first process gas and the second process gas are fluorine-containing gases.

[0109] (Supplementary Note 19) The etching method according to any one of Supplementary Note 1 to Supplementary Note 18, wherein (a) includes: (a1) a step of preparing a substrate, the substrate comprising the etching target film, the boron-containing film, a first film on the boron-containing film, and a second film on the first film, the second film having a sidewall defining at least one second opening exposing the first film; and (a2) a step of etching the first film through the second opening to form the first opening penetrating the first film and the second film, thereby forming the mask.

[0110] (Supplementary Note 20) The etching method according to any one of Supplementary Note 1 to Supplementary Note 19, wherein (b) and (c) are performed in different chambers.

[0111] (Supplementary Note 21) The etching method according to any one of Supplementary Note 1 to Supplementary Note 19, wherein (a), (b), and (c) are performed in the same chamber.

[0112] (Supplementary Note 22) An etching method comprising: (a) preparing a substrate, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) forming a deposited film containing a metal and / or a semiconductor element on an upper surface of the mask; and (c) etching the boron-containing film with plasma generated from a first process gas through the first opening.

[0113] (Supplementary Note 23) A plasma processing system comprising: a chamber; a substrate support provided in the chamber; and a controller, wherein the controller is configured to execute controls including: (a) control of preparing a substrate, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) control of forming a deposited film containing a metal and / or a semiconductor element on an upper surface of the mask; and (c) control of etching the boron-containing film with plasma generated from a first process gas through the first opening.

[0114] 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 each embodiment without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments.

[0115] REFERENCE SIGNS LIST 1: Plasma processing apparatus, 2: Control unit, 10: Plasma processing chamber, 10a: Sidewall, 10s: Plasma processing space, 11: Substrate support, 112: Ring assembly, 13: Shower head, 13a: Gas supply port, 20: Gas supply unit, 31a: First RF generator, 31b: Second RF generator, 32a: First DC generator, W: Substrate, F1: Film to be etched, F2: Boron-containing film, F3: Mask, F3a: Sidewall, OP1: First opening, F4: Boron-containing deposited film, DF: Deposited film, F5: First film, F6: Second film, F6a: Sidewall, OP2: Second opening

Claims

1. An etching method comprising: (a) preparing a substrate, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) forming a deposited film containing a metal and / or semiconductor element on an upper surface of the mask; (c) etching the boron-containing film with plasma generated from a first process gas through the first opening; and (d) etching the film to be etched with plasma generated from a second process gas through the first opening.

2. The etching method according to claim 1, wherein in (b), the deposited film is (i) not formed on the boron-containing film, or (ii) formed on the boron-containing film to a thickness thinner than that formed on the upper surface of the mask.

3. The etching method according to claim 1, further comprising the step of forming a boron-containing deposition film on the sidewalls of the mask between steps (a) and (b).

4. The etching method according to claim 3, wherein the boron-containing deposited film is formed by sputtering the boron-containing film.

5. The etching method of claim 3, wherein in (b), the deposited film is (i) not formed on the sidewalls of the mask, or (ii) formed thinner on the sidewalls of the mask than on the top surface of the mask.

6. The etching method according to claim 1, wherein in step (b), the deposited film is formed on the upper surface of the mask and on the sidewalls of the mask.

7. The etching method according to any one of claims 1 to 6, wherein the film to be etched includes at least one film selected from the group consisting of a silicon-containing film, a carbon-containing film, and a metal-containing film.

8. The etching method according to any one of claims 1 to 6, wherein the boron-containing film includes at least one film selected from the group consisting of a boron film, a boron nitride film, a boron oxide film, and a boron carbide film.

9. The etching method according to any one of claims 1 to 6, wherein the mask is a metal-containing resist.

10. The etching method according to any one of claims 1 to 6, wherein the mask is a chemically amplified resist.

11. The etching method according to any one of claims 1 to 6, wherein the deposited film contains at least one element selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge.

12. The etching method according to any one of claims 1 to 6, wherein (b) comprises: (b1) a step of exposing the substrate to a precursor gas containing a metal; and (b2) a step of exposing the substrate to a reactive gas or plasma generated from the reactive gas.

13. The etching method of claim 12, wherein the precursor gas contains at least one halide selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, Zn, Si, and Ge.

14. The etching method of claim 13, wherein the precursor gas contains a halide of at least one metal selected from the group consisting of Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, Sb, and Zn, and a halide of at least one semiconductor element selected from the group consisting of Si and Ge.

15. The etching method of claim 14, wherein the precursor gas further comprises an element different from the metal and the semiconductor element.

16. The reaction gas is NH ３ , N ２ , N ２ H ４ , N ２ H ２ , O ２ , O ３ , H ２ O, NO, N ２ O, H ２ , H ２ S, CH ４ , and SiH ４ The etching method according to claim 13, comprising at least one selected from the group consisting of:

17. The etching method according to any one of claims 1 to 6, wherein the first process gas contains at least one gas selected from the group consisting of a fluorine-containing gas, a chlorine-containing gas, a bromine-containing gas, a carbon-containing gas, and a hydrogen-containing gas.

18. The etching method according to any one of claims 1 to 6, wherein the first process gas and the second process gas are fluorine-containing gases.

19. The etching method according to any one of claims 1 to 6, wherein (a) comprises: (a1) a step of preparing a substrate, the substrate comprising the etching target film, the boron-containing film, a first film on the boron-containing film, and a second film on the first film, the second film having a sidewall defining at least one second opening exposing the first film; and (a2) a step of etching the first film through the second opening to form the first opening penetrating the first film and the second film, thereby forming the mask.

20. The etching method according to any one of claims 1 to 6, wherein steps (b) and (c) are carried out in separate chambers.

21. The etching method according to any one of claims 1 to 6, wherein (a), (b) and (c) are carried out in the same chamber.

22. An etching method comprising: (a) preparing a substrate, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) forming a deposited film containing a metal and / or semiconductor element on an upper surface of the mask; and (c) etching the boron-containing film through the first opening with plasma generated from a first process gas.

23. A plasma processing system comprising: a chamber; a substrate support provided within the chamber; and a controller, wherein the controller is configured to execute controls including: (a) controlling a substrate preparation, the substrate comprising a film to be etched, a boron-containing film on the film to be etched, and a mask on the boron-containing film, the mask having sidewalls defining at least one first opening exposing the boron-containing film; (b) controlling a deposition film including a metal and / or a semiconductor element on an upper surface of the mask; and (c) controlling etching the boron-containing film with plasma generated from a first process gas through the first opening.

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