Etching method and plasma processing apparatus

Abstract

To provide technology capable of suppressing bowing.SOLUTION: There is provided an etching method. The method includes the steps of: (a) providing a substrate having an etching target film and a mask on the etching target film, on a substrate support within a chamber; (b) etching the etching target film to form a recess under a condition that a pressure within the chamber is controlled to a first pressure, and a temperature of the substrate support is controlled to a first temperature; and (c) forming a metal-containing film on a portion of a side wall of the recess by using plasma generated from processing gas containing metal-containing gas, under a condition that the pressure within the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature equal to or less than the first temperature.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Exemplary embodiments of the present disclosure relate to an etching method and a plasma processing apparatus. [Background technology]

[0002] Patent Document 1 discloses a technique for etching a silicon-containing film while suppressing bowing by etching the silicon-containing film partway with plasma and then forming a carbon-containing film on the silicon-containing film without generating plasma. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-21546 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for suppressing bowing. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, there is provided an etching method including: (a) providing a substrate having a film to be etched and a mask on the film to be etched on a substrate support in a chamber; (b) etching the film to be etched to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; and (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure and the temperature of the substrate support is controlled to a second temperature equal to or lower than the first temperature. [Effects of the Invention]

[0006] According to one exemplary embodiment of the present disclosure, a technique for suppressing bowing can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing apparatus. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of an inductively coupled plasma processing apparatus. [Figure 3] FIG. 10 is a diagram for explaining an example of bowing. [Figure 4] 1 is a flowchart illustrating the method. [Figure 5] 1 is a diagram showing an example of a cross-sectional structure of a substrate W provided in step ST1. FIG. [Figure 6] 10 is a diagram showing an example of a cross-sectional structure of the substrate W after being processed in step ST2. FIG. [Figure 7] 10A to 10C are diagrams illustrating an example of a process for forming a metal-containing film in step ST3. [Figure 8] FIG. 10 is a diagram showing an example of the cross-sectional structure of the substrate W after processing at step ST4. DETAILED DESCRIPTION OF THE INVENTION

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

[0009] In one exemplary embodiment, an etching method is provided, including: (a) providing a substrate having a film to be etched and a mask on the film to be etched on a substrate support in a chamber; (b) etching the film to be etched to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; and (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure and the temperature of the substrate support is controlled to a second temperature equal to or lower than the first temperature.

[0010] In one exemplary embodiment, in step (c), the metal-containing film is formed on the sidewall on the bottom side of the recess.

[0011] In one exemplary embodiment, in step (c), the metal-containing film is formed at and near the bottom of the recess.

[0012] In one exemplary embodiment, in step (c), the metal-containing film is formed on the sidewalls at a position deeper than halfway through the depth of the recess.

[0013] In one exemplary embodiment, during step (c), the metal-containing film is formed from the bottom of the recess upward.

[0014] In one exemplary embodiment, the aspect ratio of the recess is 20 or greater at the end of step (b).

[0015] In one exemplary embodiment, (d) after step (c), further comprises the step of further etching the recess.

[0016] In one exemplary embodiment, steps (c) and (d) are alternately repeated multiple times.

[0017] In one exemplary embodiment, the depth of the recess at the end of step (b) is 30% or more of the depth of the recess at the end of etching.

[0018] In one exemplary embodiment, the process gas further comprises a reducing gas.

[0019] In one exemplary embodiment, the metal-containing gas comprises at least one metal selected from the group consisting of tungsten, titanium, and molybdenum.

[0020] In one exemplary embodiment, the metal-containing gas further comprises a halogen.

[0021] In one exemplary embodiment, the second temperature is less than 0°C.

[0022] In one exemplary embodiment, the second pressure is greater than or equal to 150 mTorr.

[0023] In one exemplary embodiment, the film to be etched comprises carbon and the mask comprises silicon or metal.

[0024] In one exemplary embodiment, in step (b), the target film is etched using plasma generated from a processing gas containing an oxygen-containing gas.

[0025] In one exemplary embodiment, the film to be etched comprises silicon and the mask comprises carbon or metal.

[0026] In one exemplary embodiment, in step (b), the target film is etched using plasma generated from a processing gas containing a fluorine-containing gas.

[0027] In one exemplary embodiment, an etching method is provided, including: (a) providing a substrate having a recess on a substrate support in a chamber; and (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to 150 mTorr or more and the temperature of the substrate support is controlled to less than 0°C.

[0028] In one exemplary embodiment, there is provided a plasma processing apparatus having a chamber and a controller, wherein the controller performs the following controls: (a) providing a substrate having a film to be etched and a mask on the film to be etched on a substrate support in the chamber; (b) etching the film to be etched to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; and (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure and the temperature of the substrate support is controlled to a second temperature equal to or lower than the first temperature.

[0029] 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.

[0030] <Configuration example of plasma processing apparatus> FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing apparatus. In one embodiment, the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a control unit 2, a plasma processing chamber 10, a substrate support unit 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 unit 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0031] 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 capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generating units may be used, including alternating current (AC) plasma generating units and direct current (DC) plasma generating units. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0032] 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 configured as a system external to 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. The 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 each element of the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0033] The following describes a configuration example of an inductively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of an inductively coupled plasma processing apparatus.

[0034] The inductively coupled plasma processing apparatus 1 includes a control unit 2, a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. The plasma processing apparatus 1 also includes a substrate support 11, a gas inlet, and an antenna 14. The substrate support 11 is disposed within the plasma processing chamber 10 (hereinafter also referred to as "chamber 10"). The antenna 14 is disposed on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, a sidewall 102 of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded.

[0035] 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.

[0036] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a bias electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple bias electrodes. Alternatively, the electrostatic electrode 1111b may function as a bias electrode. Therefore, the substrate support 11 includes at least one bias electrode.

[0037] 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.

[0038] 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.

[0039] The gas inlet is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the gas inlet includes a center gas injector (CGI) 13. The center gas injector 13 is disposed above the substrate support 11 and attached to a central opening formed in the dielectric window 101. The center gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet port 13c. The process gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas inlet port 13c. Note that the gas inlet may include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 102 in addition to or instead of the center gas injector 13.

[0040] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the gas inlet through a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0041] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one bias electrode and the antenna 14. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generating unit 12. Furthermore, by supplying a bias RF signal to the at least one bias electrode, a bias potential is generated on the substrate W, thereby attracting ions in the formed plasma to the substrate W.

[0042] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to the antenna 14 via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0043] The second RF generating unit 31b is coupled to at least one bias electrode via at least one impedance matching circuit and 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 generating unit 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one bias electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0044] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a bias DC generator 32a. In one embodiment, the bias DC generator 32a is connected to at least one bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to the at least one bias electrode.

[0045] In various embodiments, the bias DC signal may be pulsed. In this case, a sequence of voltage pulses is applied to at least one bias electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the bias DC generator 32a and at least one bias electrode. Thus, the bias DC generator 32a and the waveform generator constitute a voltage pulse generator. The voltage pulses may have either positive or negative polarity. The sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The bias DC generator 32a may be provided in addition to the RF power supply 31 or may be provided instead of the second RF generator 31b.

[0046] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the RF power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generator may be connected to both the outer coil and the inner coil, or separate RF generators may be connected to the outer coil and the inner coil separately.

[0047] 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 regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0048] <An example from Boeing> Bowing is known as one of the shape abnormalities that occur in plasma etching. Bowing is a phenomenon in which the opening width of a portion of the sidewall of a recess formed by etching becomes larger than the opening width at the top of the recess. The portion where bowing occurs has, for example, a barrel-like shape in cross section. Bowing is thought to occur when part of the sidewall of the recess is removed by ions that recoil from a mask or the like.

[0049] 3 is a diagram for explaining an example of bowing, showing an example of a cross-sectional structure in which an etching target film EF of a substrate W is plasma-etched through a mask MK having an opening OP until the bottom of a recess RC reaches an underlayer film UF.

[0050] In the example shown in Figure 3, the opening dimension CD is on the upper side of the recess RC (low to medium aspect ratio region). B1 (>Opening dimension CD T The first bowing B1 occurs at the bottom side of the recess (high aspect ratio region). B2 (>Opening dimension CDT ) A second bowing B2 occurs. The first bowing B1 is sometimes called a top bowing, and the second bowing B2 is sometimes called a middle bowing or a second bowing. The second bowing B2 occurs in the high aspect ratio region on the bottom side of the recess RC, and it has been difficult to suppress this type of bowing in the past.

[0051] An etching method according to an exemplary embodiment of the present disclosure can suppress bowing that occurs in such high aspect ratio regions, as will be described below with reference to FIGS.

[0052] <Example of etching method> 4 is a flowchart showing an example of an etching method (hereinafter also referred to as "the method") according to one illustrative embodiment. As shown in FIG. 4, the method includes step ST1 of providing a substrate, step ST2 of etching the substrate to form recesses, step ST3 of forming a metal-containing film in the recesses, and step ST4 of further etching the recesses. The processing in each step may be performed by the plasma processing apparatus 1 described above. The following describes an example in which the control unit 2 controls each part of the inductively coupled plasma processing apparatus 1 (see FIG. 2) to perform the method on a substrate W.

[0053] (Process ST1: Providing the substrate) In step ST1, a substrate W is provided in a plasma processing space 10s of the plasma processing apparatus 1. The substrate W is carried into the chamber 10 by a transfer arm and placed on the central region 111a of the substrate support member 11. The substrate W is attracted and held on the substrate support member 11 by an electrostatic chuck 1111.

[0054] 5 is a diagram showing an example of the cross-sectional structure of a substrate W provided in step ST1. The substrate W has an etching target film EF and a mask MK. The substrate W may further include an undercoat film UF. The substrate W may be used in the manufacture of semiconductor devices. The semiconductor devices include, for example, semiconductor memory devices such as DRAMs and 3D-NAND flash memories.

[0055] In one embodiment, the underlayer UF is a silicon wafer, an organic film, a dielectric film, a metal film, a semiconductor film, or a laminate film thereof formed on a silicon wafer. In one embodiment, the underlayer UF includes at least one film selected from the group consisting of a silicon-containing film, a carbon-containing film, and a metal-containing film.

[0056] The etching target film EF is a film that is etched in this method. The etching target film EF may be composed of a single film, or may be composed of a plurality of films stacked together.

[0057] In one embodiment, the etching target film EF is a film containing carbon or silicon. In one embodiment, the etching target film EF is a silicon-containing film. The silicon-containing film is, for example, a silicon oxide film, a silicon nitride film, a silicon carbonitride film, a polycrystalline silicon film, or a laminated film containing two or more of these films. For example, the silicon-containing film may be formed by alternately stacking silicon oxide films and silicon nitride films. For example, the silicon-containing film may be formed by alternately stacking silicon oxide films and polycrystalline silicon films. For example, the silicon-containing film may be a laminated film containing a silicon nitride film, a silicon oxide film, and a polycrystalline silicon film. In one embodiment, the etching target film EF is a carbon-containing film. For example, the carbon-containing film is, for example, an amorphous carbon (ACL) film, a spin-on carbon (SOC) film, or a photoresist film. The amorphous carbon (ACL) film may be doped with an element such as boron, and may be, for example, a boron-containing amorphous carbon film (B-doped ACL), an arsenic-containing amorphous carbon film (As-doped ACL), a tungsten-containing amorphous carbon film (W-doped ACL), or a xenon-containing amorphous carbon film (Xe-doped ACL).

[0058] In one embodiment, the etching target film EF may include a metal-containing film. The metal-containing film may be, for example, a film containing at least one selected from the group consisting of tungsten, titanium, and molybdenum.

[0059] The mask MK may have a pattern to be transferred to the etching target film EF by etching. The mask MK may be a single-layer mask consisting of one layer, or may be a multi-layer mask consisting of two or more layers. As shown in FIG. 5, the mask MK defines at least one opening OP on the etching target film EF. The opening OP is a space above the etching target film EF and is surrounded by the sidewall of the mask MK. That is, the upper surface of the etching target film EF has an area covered by the mask MK and an area exposed at the bottom of the opening OP.

[0060] The openings OP may have any shape when viewed from above the substrate W, i.e., when the substrate W is viewed from top to bottom in FIG. 5. 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 MK may have multiple side walls that define multiple openings OP. The multiple openings OP may each have a linear shape and be arranged at regular intervals to form a line-and-space pattern. Furthermore, the multiple openings OP may each have a hole shape and form an array pattern.

[0061] The mask MK may be made of a material whose etching rate with respect to the plasma generated in steps ST2 and ST4 is lower than that of the etching target film EF. That is, the mask MK may be selected appropriately depending on the material of the etching target film EF.

[0062] For example, when the film EF to be etched is a silicon-containing film, the mask MK may be a carbon-containing mask or a metal-containing mask. The carbon-containing mask may be an amorphous carbon film, a photoresist film, or a spin-on carbon (SOC) film. In one example, the mask MK is an amorphous carbon film. The metal-containing mask may be a film containing at least one selected from the group consisting of tungsten, titanium, and molybdenum. In one example, the metal-containing mask is a tungsten silicide film.

[0063] For example, when the etching target film EF is a carbon-containing film, the mask MK may be a silicon-containing mask or a metal-containing mask. The silicon-containing mask may be a silicon oxynitride film, a silicon oxide film, or a silicon nitride film. The metal-containing mask may be a film containing at least one selected from the group consisting of tungsten, titanium, and molybdenum. In one example, the metal-containing mask is a tungsten silicide film.

[0064] For example, when the etching target film EF is a metal-containing film, the mask MK may be a silicon-containing mask such as a silicon oxide film.

[0065] Each film constituting the substrate W (underlying film UF, etching target film EF, or mask MK) may be formed by a CVD method, an ALD method, a spin coating method, or the like. The opening OP in the mask MK may be formed by etching the mask MK, or may be formed by lithography. Each film may be a flat film or may have an uneven surface. The substrate W may further have another film below the underlying film UF. In this case, recesses having shapes corresponding to the openings OP may be formed in the etching target film EF and underlying film UF, and these recesses may be used as masks for etching the other film.

[0066] At least a part of the process of forming each film on the substrate W may be performed within the space of the chamber 10. In one example, the step of etching the mask MK to form the opening OP may be performed in the chamber 10. That is, the opening OP and the etching of the etching target film EF in step ST2, which will be described later, may be performed consecutively within the same chamber. Alternatively, after all of the films on the substrate W are formed in an apparatus or chamber external to the plasma processing apparatus 1, the substrate W may be provided by being loaded into the plasma processing space 10s of the plasma processing apparatus 1 and placed in the central region 111a of the substrate support 11.

[0067] In one embodiment, after the substrate W is provided in the central region 111a of the substrate support 11, the substrate support 11 is controlled to a first temperature by a temperature control module. In one example, controlling the temperature of the substrate support 11 to the first temperature includes setting the temperature of the heat transfer fluid flowing through the flow path 1110a or the heater temperature to the first temperature, or to a temperature different from the first temperature. The timing at which the heat transfer fluid starts flowing through the flow path 1110a may be before or after the substrate W is placed on the substrate support 11, or may be simultaneous. Furthermore, the temperature of the substrate support 11 may be controlled to the first temperature before step ST1. That is, the substrate W may be provided to the substrate support 11 after the temperature of the substrate support 11 is controlled to the first temperature.

[0068] The first temperature may be set appropriately depending on the type of etching target film EF and the type of process gas (first process gas) used in step ST2. In one embodiment, the first temperature is less than 0° C. In one example, the first temperature is −10° C. or less, −20° C. or less, −30° C. or less, −40° C. or less, −50° C. or less, −60° C. or less, or −70° C. or less.

[0069] In one embodiment, the substrate W may be controlled to the first temperature instead of controlling the substrate support 11 to the first temperature. Controlling the temperature of the substrate W to the first temperature includes setting the temperature of the substrate support 11, the temperature of the heat transfer fluid flowing through the flow path 1110a, and / or the heater temperature to the first temperature or to a temperature different from the first temperature.

[0070] (Step ST2: Formation of recesses) In step ST2, the etching target film EF of the substrate W is etched to form a recess.

[0071] First, a first process gas is supplied from the gas supply unit 20 into the plasma processing space 10s. The first process gas may be appropriately selected so that the film EF to be etched has a sufficient etching selectivity relative to the mask MK. For example, if the film EF to be etched is a silicon-containing film, the first process gas may contain a fluorine-containing gas. Examples of the fluorine-containing gas include hydrogen fluoride gas (HF gas), a fluorocarbon gas, or a hydrofluorocarbon gas. For example, if the film to be etched is a carbon-containing film, the first process gas may contain an oxygen-containing gas. Examples of the oxygen-containing gas include O gas, CO gas, CO gas, or COS gas. For example, if the film to be etched is a metal-containing film, the first process gas may contain a halogen-containing gas (e.g., BCl gas, SiCl gas, NF gas, etc.) and an oxygen-containing gas (e.g., O gas, CO gas, or CO gas). The halogen-containing gas and the oxygen-containing gas may be supplied simultaneously or alternately to the plasma processing space 10s.

[0072] During the process in step ST2, the gases contained in the first process gas and their flow rates (partial pressures) may or may not be changed. For example, if the etching target film EF is composed of a stack of films made up of different types of films, the composition of the process gas and the flow rates (partial pressures) of each gas may be changed as the etching progresses (i.e., depending on the type of film to be etched).

[0073] Next, a source RF signal is supplied to the antenna 14. This generates a high-frequency electric field in the plasma processing space 10s, generating plasma from the first processing gas and etching the etching target film EF. 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 active species such as ions and radicals in the plasma are attracted to the substrate W, which can promote etching of the etching target film EF. The bias signal may be a bias RF signal supplied from the second RF generator 31b. Alternatively, the bias signal may be a bias DC signal supplied from the DC generator 32a.

[0074] The source RF signal and the bias signal may both be continuous waves or pulse waves, or one may be continuous waves and the other a pulse wave. When both the source RF signal and the bias signal are pulse waves, the periods of the two pulse waves may or may not be synchronized. The duty ratio of the source RF signal and / or bias signal pulse waves may be set appropriately, for example, 1 to 80% or 5 to 50%. Furthermore, when a bias DC signal is used as the bias signal, the pulse wave may have a waveform that is rectangular, trapezoidal, triangular, or a combination thereof. The polarity of the bias DC signal may be negative or positive, as long as the potential of the substrate W is set so as to apply a potential difference between the plasma and the substrate and attract ions.

[0075] In step ST2, supply and stop of at least one of the source RF signal and the bias signal may be alternately repeated. For example, supply and stop of the bias signal may be alternately repeated while the source RF signal is continuously supplied. Alternatively, for example, supply and stop of the source RF signal may be alternately repeated while the bias signal is continuously supplied. Alternatively, for example, supply and stop of both the source RF signal and the bias signal may be alternately repeated.

[0076] During the processing in step ST2, the temperature of the substrate support 11 is controlled to the first temperature set in step ST1. In one embodiment, instead of the temperature of the substrate support 11, the temperature of the substrate W may be controlled to the first temperature.

[0077] During the process in step ST2, the pressure in the plasma processing space 10s is controlled to a first pressure. In one embodiment, the first pressure is less than 150 mTorr (20 Pa). In one example, the first pressure may be 100 mTorr (13.3 Pa) or less, and is 50 mTorr (6.7 Pa) or less.

[0078] 6 is a diagram showing an example of the cross-sectional structure of the substrate W after processing in step ST2. As shown in Fig. 6, the etching in step ST2 etches the portion of the etching target film EF exposed at the opening OP in the depth direction (from top to bottom in Fig. 6). As a result, a recess RC is formed in the etching target film EF.

[0079] By the processing in step ST2, the portion of the etching target film EF that is not covered by the mask MK (the portion exposed at the opening OP) is etched to form a recess RC. The recess RC is a space defined by a sidewall SS and a bottom BT.

[0080] In one embodiment, the aspect ratio of the recess RC after the process in step ST2 (in the example shown in FIG. 6, the opening dimension CD of the recess RC relative to the depth D1 of the recess RC) is T The aspect ratio of the recess RC after the process in step ST2 may be 20 or more, 40 or more, 50 or more, or 60 or more. In one example, the aspect ratio of the recess RC after the process in step ST2 is 40 or more.

[0081] In one embodiment, the depth of the recess RC after processing in step ST2 (depth D1 of the recess RC in the example shown in FIG. 6) may be 30% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more of the final etching depth (depth D2 to the base film UF in the example shown in FIG. 6).

[0082] (Step ST3: Formation of metal-containing film) In step ST3, a metal-containing film is formed in the recesses RC of the etching target film EF. First, a second processing gas containing a metal-containing gas is supplied from the gas supply unit 20 into the plasma processing space 10s.

[0083] In one embodiment, the metal-containing gas comprises at least one metal selected from the group consisting of tungsten, titanium, and molybdenum. In one embodiment, the metal-containing gas may further comprise a halogen.

[0084] In one embodiment, the metal-containing gas may be a gas containing tungsten and a halogen, and in one example is WF x Cl y The tungsten-containing gas may be a gas containing tungsten and fluorine, such as tungsten difluoride (WF2) gas, tungsten tetrafluoride (WF4) gas, tungsten pentafluoride (WF5) gas, or tungsten hexafluoride (WF6) gas, or a gas containing tungsten and chlorine, such as tungsten dichloride (WCl2) gas, tungsten tetrachloride (WCl4) gas, tungsten pentachloride (WCl5) gas, or tungsten hexachloride (WCl6) gas. Among these, at least one of WF6 gas and WCl6 gas may be used. In one embodiment, the metal-containing gas may be a gas containing molybdenum or titanium and a halogen, such as MoF4 gas, MoCl6 gas, or TiCl4 gas.

[0085] In one embodiment, the flow rate of the metal-containing gas in the second process gas may be 50 vol. % or less, 40 vol. % or less, 30 vol. % or less, 20 vol. % or less, 10 vol. % or less, 5 vol. % or less, or 3 vol. % or less of the total flow rate of the second process gas (excluding the flow rate of the inert gas, if the second process gas includes an inert gas).

[0086] In one embodiment, the metal-containing gas may be a gas with a low vapor pressure, such as a gas that reaches vapor pressure at a temperature equal to or higher than the temperature indicated by the temperature-vapor pressure curve of CF.

[0087] In one embodiment, the second process gas may further include a reducing gas, such as at least one selected from the group consisting of H gas, SiH gas, CH gas, C H gas, C H gas, C H gas, CO gas, CO gas, and COS gas.

[0088] In one embodiment, the second process gas may further include an inert gas, which may be, for example, a noble gas such as Ar gas, He gas, or Kr gas, or nitrogen gas.

[0089] Next, a source RF signal is supplied to the antenna 14. This generates a high-frequency electric field in the plasma processing space 10s, and plasma is generated from the second processing gas. As a result, a metal-containing film is formed in the recess RC of the etching target film EF. At this time, a bias signal does not need to be supplied to the lower electrode of the substrate support member 11. Alternatively, a bias signal may be supplied to the lower electrode of the substrate support member 11. In this case, the level (power level or voltage level) of the bias signal may be lower than the level of the bias signal supplied to the substrate support member 11 in step ST2 or step ST4.

[0090] During the treatment in step ST3, the temperature of the substrate support 11 is controlled to a second temperature. The second temperature is a temperature equal to or lower than the first temperature. In one embodiment, the second temperature is less than 0°C. For example, the second temperature is −10°C or lower, −20°C or lower, −30°C or lower, −40°C or lower, −50°C or lower, −60°C or lower, or −70°C or lower. Note that in one embodiment, the temperature of the substrate W may be controlled to the second temperature instead of the temperature of the substrate support 11.

[0091] During the processing in step ST3, the pressure in the plasma processing space 10s is controlled to a second pressure. The second pressure is higher than the first pressure. In one embodiment, the second pressure is 150 mTorr (20 Pa) or higher. In one example, the second pressure is 200 mTorr (26.7 Pa) or higher, 300 mTorr (40 Pa) or higher, or 400 mTorr (53.3 Pa) or higher.

[0092] In step ST3, a metal-containing film MD is formed in the recess RC by plasma generated from a second process gas containing a metal-containing gas. In one embodiment, the metal-containing film MD is formed on a bottom sidewall SS of the recess RC. In one embodiment, the metal-containing film may be continuously formed from the bottom sidewall SS to a portion of the top sidewall SS of the recess RC, or may not be formed on the top sidewall SS of the recess RC. Note that the "bottom side" may be a position below (deeper than) half the depth D1 (see FIG. 6 ) of the recess RC, and the "top side" may be a position above (shallower than) half the depth D1 of the recess RC. In one embodiment, the metal-containing film MD may be formed on the bottom BT of the recess RC. The metal-containing film MD may be continuously formed over the bottom BT of the recess RC and the sidewall SS near the bottom BT. The metal-containing film MD may provide protection for the sidewall SS on which the metal-containing film MD is formed during further etching of the recess RC in step ST4.

[0093] 7A to 7C are diagrams illustrating an example of the process of forming a metal-containing film in step ST3. In FIG. 7A, (A) to (C) illustrate an example of the cross-sectional state of the substrate W at the initial, middle, and final stages of step ST3, respectively. As shown in order from (A) to (C) in FIG. 7A, the metal-containing film MD may be formed bottom-up on the sidewall SS of the recess RC from the bottom BT upward. At the end of step ST3 (FIG. 7C), the metal-containing film MD has been formed across the bottom BT and the sidewall SS at a position lower (deeper) than the depth D3. In one embodiment, the depth D3 may be 50% (half) of the depth D1 of the recess RC, or may be 60%, 70%, 80%, or 90%.

[0094] (Step ST4: Etching of recesses) In step ST4, the recess RC of the etching target film EF is further etched. Step ST4 may be performed in the same manner as the etching in step ST2 described above. Note that in step ST4, at least some of the etching conditions (type of process gas, pressure in the chamber 10, temperature of the substrate support 11, level of the source RF signal, presence or absence of a bias signal or its level, etc.) may be changed from those in step ST2.

[0095] In the etching of step ST4, the metal-containing film MD can protect the sidewall SS on which the metal-containing film MD is formed, that is, can prevent the sidewall SS in that portion from expanding in the width direction, i.e., preventing bowing.

[0096] Fig. 8 is a diagram showing an example of the cross-sectional structure of the substrate W after processing at step ST4. As shown in Fig. 8, the processing at step ST4 causes the recess RC to be further etched in the depth direction to a depth D2, and the bottom BT reaches the base film UF. In the example shown in Fig. 8, the metal-containing film MD is removed as the etching progresses, but the protective effect of the metal-containing film MD prevents bowing from occurring in the sidewall SS of the recess RC, including in the high aspect ratio region.

[0097] According to this method, a metal-containing film is formed on at least the bottom sidewall SS of the recess RC in step ST3. This can prevent bowing from occurring on the bottom side (high aspect ratio region) of the recess RC during etching of the recess in step ST4. That is, the occurrence of the second bowing (middle bowing, second bowing) as shown in FIG. 3 can also be prevented.

[0098] <Modification> Various modifications of this method may be made without departing from the scope and spirit of the present disclosure. In one embodiment, the processes according to this method do not have to be performed in the same chamber 10. For example, steps ST2 and ST3 may be performed in different plasma processing chambers. Also, for example, steps ST3 and ST4 may be performed in different plasma processing chambers.

[0099] In one embodiment, Step ST3 and Step ST4 may be repeated. That is, Step ST3 and Step ST4 may be considered as one cycle, and this cycle may be repeated multiple times to alternately form a metal-containing film and etch the recesses.

[0100] <Example> Next, examples of the present method will be described, but the present disclosure is not limited to the following examples.

[0101] Example 1 Using the plasma processing apparatus 1 shown in Fig. 2, a substrate having a structure similar to that of the substrate W shown in Fig. 5 was etched according to the flowchart described in Fig. 4. The mask MK was a silicon oxynitride film, and the etching target film EF was an amorphous carbon film. The opening OP of the mask MK had a hole shape and an opening diameter of 80 nm.

[0102] In Example 1, in step ST2, the first process gas contained O gas and COS gas. In step ST2, a bias RF signal was supplied in addition to the source RF signal. In step ST2, the pressure in the chamber 10 was controlled to 30 mTorr, and the temperature of the substrate support 11 was controlled to −60° C. Step ST2 was performed for 240 seconds.

[0103] In Example 1, in step ST3, the second process gas contained WF gas (metal-containing gas), H gas (reducing gas), and Ar gas (inert gas). In step ST3, only a source RF signal was supplied, and no bias signal was supplied. In step ST3, the pressure in the chamber 10 was controlled to 200 mTorr, and the temperature of the substrate support 11 was controlled to −60° C. Step ST3 was performed for 60 seconds.

[0104] In Example 1, step ST4 was performed under the same conditions as step ST2, and step ST4 was performed for 180 seconds.

[0105] A recess RC of approximately 3.5 μm was formed in the etching target film EF by the treatment according to Example 1. When the cross section of the recess RC was observed, no bowing was observed even in a high aspect ratio region with a depth of 2 μm or less.

[0106] <Experiment> Next, an experiment was carried out to verify the time dependency, temperature dependency, and pressure dependency of the formation of the metal-containing film MD in step ST2. The present disclosure is not limited to the following experiment.

[0107] (time dependent) For the same substrate as in Example 1, step ST2 was performed for 10 seconds, 20 seconds, and 60 seconds under the same conditions as in Example 1, and the film formation status of the metal-containing film MD was observed. For the substrate on which step ST2 was performed for 10 seconds, a metal-containing film MD was formed on the bottom of the recess and on the sidewall up to 53 nm above the bottom. For the substrate on which step ST2 was performed for 20 seconds, a metal-containing film MD was formed on the bottom of the recess and on the sidewall up to 64 nm above the bottom. For the substrate on which step ST2 was performed for 60 seconds, a metal-containing film MD was formed on the bottom of the recess and on the sidewall up to 249 nm above the bottom. In other words, by extending the processing time of step ST2, the metal-containing film MD was formed further upward from the bottom.

[0108] (temperature dependence) For the same substrate as in Example 1, step ST2 was performed for 60 seconds under the same conditions as in Example 1, except that the temperature of the substrate support 11 was changed, and the state of formation of the metal-containing film MD was observed. For the substrate in which the temperature of the substrate support 11 was set to -60°C, the metal-containing film MD was formed on the bottom and the sidewalls near the bottom. In contrast, for the substrate in which the temperature of the substrate support 11 was set to 0°C, no formation of the metal-containing film MD was confirmed.

[0109] (pressure dependence) For the same substrate as in Example 1, step ST2 was performed for 60 seconds under the same conditions as in Example 1, except that the pressure in chamber 10 was changed, and the film formation state of the metal-containing film MD was observed. For the substrates for which the pressure in chamber 10 was set to 150 mTorr, 200 mTorr, 300 mTorr, and 400 mTorr, the metal-containing film MD was formed on the bottom and sidewalls near the bottom. In contrast, for the substrates for which the pressure in chamber 10 was set to 100 mTorr, the formation of the metal-containing film MD was not confirmed.

[0110] Embodiments of the present disclosure further include the following aspects.

[0111] (Appendix 1) 1. An etching method comprising: (a) providing a substrate on a substrate support in a chamber, the substrate having a film to be etched and a mask on the film to be etched; (b) etching the etching target film to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature lower than or equal to the first temperature. Etching method.

[0112] (Appendix 2) 2. The etching method according to claim 1, wherein in the step (c), the metal-containing film is formed on a sidewall on a bottom side of the recess.

[0113] (Appendix 3) 3. The etching method according to claim 1, wherein in the step (c), the metal-containing film is formed on the bottom of the recess and in the vicinity of the bottom.

[0114] (Appendix 4) 4. The etching method according to claim 1, wherein in the step (c), the metal-containing film is formed on a sidewall at a position deeper than half the depth of the recess.

[0115] (Appendix 5) 5. The etching method according to claim 1, wherein during the step (c), the metal-containing film is formed from the bottom of the recess upward.

[0116] (Appendix 6) 6. The etching method according to any one of claims 1 to 5, wherein the aspect ratio of the recess is 20 or more at the end of the step (b).

[0117] (Appendix 7) (d) The etching method according to any one of Supplementary Note 1 to Supplementary Note 6, further comprising the step of further etching the recess after the step (c).

[0118] (Appendix 8) 8. The etching method according to claim 7, wherein the steps (c) and (d) are alternately repeated multiple times.

[0119] (Appendix 9) 9. The etching method according to claim 7, wherein the depth of the recess at the end of step (b) is 30% or more of the depth of the recess at the end of etching.

[0120] (Appendix 10) 10. The etching method according to claim 1, wherein the process gas further contains a reducing gas.

[0121] (Appendix 11) 11. The etching method according to claim 1, wherein the metal-containing gas contains at least one metal selected from the group consisting of tungsten, titanium, and molybdenum.

[0122] (Appendix 12) 12. The etching method of claim 11, wherein the metal-containing gas further contains a halogen.

[0123] (Appendix 13) 13. The etching method of any one of claims 1 to 12, wherein the second temperature is less than 0°C.

[0124] (Appendix 14) 14. The etching method of claim 1, wherein the second pressure is 150 mTorr or more.

[0125] (Appendix 15) 15. The etching method of any one of claims 1 to 14, wherein the film to be etched contains carbon and the mask contains silicon or metal.

[0126] (Appendix 16) 16. The etching method according to claim 15, wherein in the step (b), the target film is etched using plasma generated from a processing gas containing an oxygen-containing gas.

[0127] (Appendix 17) 15. The etching method of any one of claims 1 to 14, wherein the film to be etched contains silicon and the mask contains carbon or metal.

[0128] (Appendix 18) 18. The etching method according to claim 17, wherein in the step (b), the target film is etched using plasma generated from a process gas containing a fluorine-containing gas.

[0129] (Appendix 19) 1. An etching method comprising: (a) providing a substrate having a recess on a substrate support in a chamber; (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to 150 mTorr or more and the temperature of the substrate support is controlled to less than 0°C. Etching method.

[0130] (Appendix 20) A plasma processing apparatus having a chamber and a control unit, The control unit (a) providing a substrate having a film to be etched and a mask on the film to be etched on a substrate support in the chamber; (b) controlling a process of etching the etching target film to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature lower than or equal to the first temperature. Plasma processing equipment.

[0131] (Appendix 21) A plasma processing apparatus having a chamber and a control unit, The control unit (a) providing a substrate having a recess on a substrate support in a chamber; (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to 150 mTorr or more and the temperature of the substrate support is controlled to less than 0°C. Plasma processing equipment.

[0132] (Appendix 22) A device manufacturing method carried out in a plasma processing apparatus having a chamber and a control unit, comprising: (a) providing a substrate on a substrate support in a chamber, the substrate having a film to be etched and a mask on the film to be etched; (b) etching the etching target film to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature lower than or equal to the first temperature. Device manufacturing methods.

[0133] (Appendix 23) A device manufacturing method carried out in a plasma processing apparatus having a chamber and a control unit, comprising: (a) providing a substrate having a recess on a substrate support in a chamber; (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to 150 mTorr or more and the temperature of the substrate support is controlled to less than 0°C. Device manufacturing methods.

[0134] (Appendix 24) A computer of a plasma processing apparatus having a chamber and a control unit, (a) providing a substrate having a film to be etched and a mask on the film to be etched on a substrate support in the chamber; (b) controlling a process of etching the etching target film to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; (c) controlling a process for forming a metal-containing film on a portion of a sidewall of the recessed portion by using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature lower than or equal to the first temperature. program.

[0135] (Appendix 25) A computer of a plasma processing apparatus having a chamber and a control unit, (a) providing a substrate having a recess on a substrate support in a chamber; (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to 150 mTorr or more and the temperature of the substrate support is controlled to less than 0°C. program.

[0136] (Appendix 26) A storage medium storing a program according to either Supplementary Note 24 or Supplementary Note 25.

[0137] 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 above embodiments 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. [Explanation of symbols]

[0138] REFERENCE SIGNS LIST 1: plasma processing apparatus, 2: control unit, 10: plasma processing chamber, 10s: plasma processing space, 11: substrate support unit, 14: antenna, 20: gas supply unit, 31a: first RF generation unit, 31b: second RF generation unit, 32a: first DC generation unit, EF: film to be etched, MD: metal-containing film, MK: mask, OP: opening, RC: recess, UF: base film, W: substrate

Claims

1. 1. An etching method comprising: (a) providing a substrate on a substrate support in a chamber, the substrate having a film to be etched and a mask on the film to be etched; (b) etching the etching target film to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; (c) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature lower than or equal to the first temperature; During the step (c), the metal-containing film is formed upward from the bottom of the recess. Etching method.

2. The etching method according to claim 1 , wherein in the step (c), the metal-containing film is formed on a sidewall on a bottom side of the recess.

3. The etching method according to claim 1 , wherein in the step (c), the metal-containing film is formed on the bottom of the recess and in the vicinity of the bottom.

4. 2. The etching method according to claim 1, wherein in the step (c), the metal-containing film is formed on a sidewall at a position deeper than half the depth of the recess.

5. 2. The etching method according to claim 1, wherein the recess has an aspect ratio of 20 or more at the end of the step (b).

6. The etching method according to claim 1 , further comprising the step of: (d) further etching the recess after the step (c).

7. 7. The etching method according to claim 6, wherein the steps (c) and (d) are alternately repeated multiple times.

8. 8. The etching method according to claim 6, wherein the depth of the recess at the end of the step (b) is 30% or more of the depth of the recess at the end of the etching.

9. The etching method of claim 1 , wherein the process gas further comprises a reducing gas.

10. 2. The etching method according to claim 1, wherein the metal-containing gas contains at least one metal selected from the group consisting of tungsten, titanium, and molybdenum.

11. The etching method of claim 10 , wherein the metal-containing gas further comprises a halogen.

12. The etching method of claim 1 , wherein the second temperature is less than 0° C.

13. 2. The etching method according to claim 1, wherein the second pressure is 150 mTorr or more.

14. The etching method according to claim 1 , wherein the film to be etched includes carbon, and the mask includes silicon or metal.

15. 15. The etching method according to claim 14, wherein in the step (b), the target film is etched using plasma generated from a process gas containing an oxygen-containing gas.

16. The etching method according to claim 1 , wherein the film to be etched includes silicon, and the mask includes carbon or metal.

17. 17. The etching method according to claim 16, wherein in the step (b), the target film is etched using plasma generated from a process gas containing a fluorine-containing gas.

18. 1. An etching method comprising: (a) providing a substrate having a recess on a substrate support in a chamber; (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas, wherein the pressure in the chamber is controlled to 150 mTorr or more and the temperature of the substrate support is controlled to less than 0°C; During the step (b), the metal-containing film is formed upward from the bottom of the recess. Etching method.

19. A plasma processing apparatus having a chamber and a control unit, The control unit (a) providing a substrate having a film to be etched and a mask on the film to be etched on a substrate support in the chamber; (b) controlling the etching target film to form a recess, wherein the pressure in the chamber is controlled to a first pressure and the temperature of the substrate support is controlled to a first temperature; and (c) controlling a process to form a metal-containing film on a portion of a sidewall of the recess by using plasma generated from a process gas including a metal-containing gas, wherein the pressure in the chamber is controlled to a second pressure higher than the first pressure, and the temperature of the substrate support is controlled to a second temperature equal to or lower than the first temperature; During the control of (c), the metal-containing film is formed from the bottom of the recess upward. Plasma processing equipment.

20. (a) providing a substrate having a recess on a substrate support in a chamber; (b) forming a metal-containing film on a portion of a sidewall of the recess using plasma generated from a process gas containing a metal-containing gas; Including, In the substrate processing method, during the step (b), the metal-containing film is formed from the bottom of the recess upward.

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