Plasma processing method and plasma processing apparatus

Abstract

To provide a technique capable of suppressing an abnormal shape in etching.SOLUTION: The present invention provides a plasma processing method for processing a substrate in a plasma processing apparatus. The plasma processing apparatus comprises: a chamber; a substrate support part arranged into the chamber; an upper electrode that is arranged so as to be opposite to the substrate support part, in which a surface opposite to the substrate support part contains a metal; and a power supply constructed by supplying a source RF signal to the substrate support part or the upper electrode. The plasma processing method contains steps of: providing the substrate onto the substrate support part, in which the substrate contains a film and a mask onto the film; (b) supplying the source RF signal to the substrate support part or the upper electrode from the power supply to generate a plasma from a processing gas containing an HF gas. The step (b) includes steps of: forming a concave part by etching the film of the substrate by the plasma; and forming a metal-containing film containing the metal on a side wall of the concave part.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Patent Document 1 discloses a method for depositing a silicon-containing deposit on a mask surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-082228 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for suppressing shape abnormalities caused by etching. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, there is provided a plasma processing method for processing a substrate in a plasma processing apparatus, the plasma processing apparatus including a chamber, a substrate support disposed within the chamber, an upper electrode disposed opposite the substrate support, the upper electrode having a surface facing the substrate support that includes a metal, and a power source configured to supply a source RF signal to the substrate support or the upper electrode, the plasma processing method including: (a) providing a substrate on the substrate support, the substrate including a film and a mask on the film; and (b) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas, the plasma processing method including (b) etching a film on the substrate with the plasma to form a recess, and forming a metal-containing film including a metal on a sidewall of the recess. Effect of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique for suppressing shape abnormalities due to etching can be provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. [Diagram 2] 2 is a diagram for explaining a configuration example of a shower head 13. FIG. [Diagram 3] 1 is a flow chart showing an example of a method MT. [Figure 4] 2 is a diagram showing an example of a cross-sectional structure of a substrate W. FIG. [Diagram 5] 11 is a diagram showing an example of a cross-sectional structure of a substrate W being processed in step ST2. FIG. [Figure 6A] FIG. 2 is a diagram showing an example of a position where a metal-containing film is formed. [Figure 6B] FIG. 2 is a diagram showing an example of a position where a metal-containing film is formed. [Figure 7] FIG. 11 is a diagram for explaining an example of processing in step ST2. [Figure 8] 13 is a flowchart showing another example of the method MT. [Figure 9] FIG. 1 shows the results of Experiment 1. [Figure 10] FIG. 1 shows the results of Experiment 1. [Figure 11] FIG. 1 shows the results of Experiments 2 and 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Each embodiment of the present disclosure will be described below.

[0009] In one exemplary embodiment, there is provided a plasma processing method for processing a substrate in a plasma processing apparatus, the plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support, the upper electrode having a surface facing the substrate support that includes a metal; and a power source configured to supply a source RF signal to the substrate support or the upper electrode, the plasma processing method including: (a) providing a substrate on the substrate support, the substrate including a film and a mask on the film; and (b) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas, the plasma processing method including (b) etching a film of the substrate by the plasma to form a recess; and forming a metal-containing film including a metal on a sidewall of the recess.

[0010] In one exemplary embodiment, the metal comprises at least one selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

[0011] In one exemplary embodiment, forming the metal-containing film includes providing a first bias signal to the top electrode and sputtering the top electrode.

[0012] In one exemplary embodiment, the level of the first bias signal is controlled to adjust at least one of the thickness and the position of the metal-containing film formed on the sidewall of the recess.

[0013] In one exemplary embodiment, the first bias signal is a negative polarity bias DC signal.

[0014] In one exemplary embodiment, the first bias signal is a bias RF signal that is different from the source RF signal.

[0015] In one exemplary embodiment, b) includes a first period and a second period, during which the first bias signal is provided at a first signal level, and during which the first bias signal is not provided or is provided at a second signal level lower than the first signal level.

[0016] In one exemplary embodiment, in (b), the first and second time periods are repeated alternately.

[0017] In one exemplary embodiment, etching the film includes providing a second bias signal to the substrate support.

[0018] In one exemplary embodiment, (b) includes a third period and a fourth period, during which the second bias signal is supplied to the substrate support at a third signal level, and during which the second bias signal is not supplied to the substrate support or is supplied at a fourth signal level less than the third level.

[0019] In one exemplary embodiment, in (b), the third and fourth periods are repeated alternately.

[0020] In one exemplary embodiment, the substrate film is a silicon-containing film.

[0021] In one exemplary embodiment, the process gas includes a reactive gas, and forming the metal-containing film includes sputtering the top electrode using the reactive gas or a plasma generated from the reactive gas.

[0022] In one exemplary embodiment, the process gas further comprises a phosphorus-containing gas.

[0023] In one exemplary embodiment, the process gas further comprises a carbon-containing gas.

[0024] In one exemplary embodiment, the process gas further comprises a halogen-containing gas other than fluorine.

[0025] In one exemplary embodiment, the process gas further comprises a metal-containing gas, the metal-containing gas comprising at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

[0026] In one exemplary embodiment, prior to (a), the method further includes a step of pre-coating a surface of the upper electrode facing the substrate support with a metal-containing material, the metal material including at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

[0027] In one exemplary embodiment, a plasma processing method for processing a substrate in a plasma processing apparatus is provided, the plasma processing apparatus comprising a chamber, a substrate support disposed within the chamber, an upper electrode disposed opposite the substrate support, and a power source configured to supply a source RF signal to the substrate support or the upper electrode, the plasma processing method including: (a) pre-coating a surface of the upper electrode facing the substrate support with a metal-containing material; (b) providing a substrate on the substrate support, the substrate including a film and a mask on the film; and (c) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas, the (c) plasma processing method including etching a film of the substrate with the plasma to form a recess, and forming a metal-containing film including a metal material on a sidewall of the recess.

[0028] In one exemplary embodiment, a plasma processing apparatus is provided, the plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support, the upper electrode having a surface facing the substrate support that includes a metal; a power supply configured to supply a source RF signal to the substrate support or the upper electrode; and a controller, the controller configured to execute: (a) control of providing a substrate on the substrate support, the substrate including a film and a mask on the film; and (b) control of supplying a source RF signal from the power supply to the substrate support or the upper electrode to generate plasma from a process gas including HF gas, the (b) step including etching a film on the substrate with the plasma to form a recess; and forming a metal-containing film including a metal on a sidewall of the recess.

[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 given the same reference numerals, and duplicated explanations will be omitted. Unless otherwise specified, the positional relationship such as up, down, left, right, etc. will be described based on the positional relationship shown in the drawing. The dimensional ratio of the drawings does not indicate the actual ratio, and the actual ratio is not limited to the illustrated ratio.

[0030] <Example of plasma processing system configuration> An example of the configuration of a plasma processing system will be described below. Fig. 1 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus.

[0031] The plasma processing system includes a capacitively coupled plasma processing device 1 and a controller 2. The capacitively coupled plasma processing device 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing device 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a shower head 13. The substrate support 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support 11. In one embodiment, the shower head 13 forms at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 has at least one gas inlet for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically isolated from the housing of the plasma processing chamber 10.

[0032] 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 the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the 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.

[0033] 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 may 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 other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. 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. Also, at least one RF / DC electrode coupled to a radio frequency (RF) power source 31 and / or a direct current (DC) power source 32 described later may be disposed in 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 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 a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Thus, the substrate support 11 includes at least one lower electrode.

[0034] 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.

[0035] 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 a brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0036] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing 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 shower head 13 also includes at least one upper electrode. Note that the gas introduction unit may include, in addition to the shower head 13, one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0037] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include one or more flow modulation devices to modulate or pulse a flow rate of the at least one process gas.

[0038] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 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 causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of a plasma generating unit configured to generate a plasma from one or more processing gases in the plasma processing chamber 10. In addition, a bias potential is generated on the substrate W by supplying a bias RF signal to the at least one lower electrode, and ion components in the formed plasma can be attracted to the substrate W.

[0039] 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 a plurality of 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.

[0040] The second RF generating unit 31b is coupled to at least one lower 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 a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0041] 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 at least one lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0042] In various embodiments, at least one of 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 a 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 a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one period. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0043] 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 adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0044] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute various steps described herein. In one embodiment, a 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 is realized, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and is read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be 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).

[0045] FIG. 2 is a diagram for explaining a configuration example of the shower head 13. In one embodiment, the shower head 13 may be composed of a base material 130 and a metal-containing material 132 on the base material 130. The base material 130 may be composed of, for example, a silicon-containing material. The metal-containing material 132 constitutes a surface facing the substrate support 11 and is exposed to the plasma processing space 10s. That is, the surface of the metal-containing material 132 is exposed to the plasma generated in the plasma processing space 10s. The metal-containing material 132 is composed of a metal-containing material containing at least one metal (hereinafter also referred to as "metal M") selected from the group consisting of tungsten, molybdenum, ruthenium, and titanium. In one embodiment, the metal-containing material contains tungsten, and includes at least one selected from the group consisting of tungsten carbide (WC), tungsten silicide (WSi), tungsten oxide (WO), tungsten nitride (WN), tungsten silicon nitride (WSiN), and tungsten silicon carbide (WSiC).

[0046] In one embodiment, the metal-containing material 132 may be formed by thermally spraying a metal-containing material containing the metal M onto the surface of the substrate 130. In one embodiment, the metal-containing material 132 may be formed by layering the metal-containing material containing the metal M onto the surface of the substrate 130 using a 3D printer or the like. In one embodiment, the substrate 130 may be made of a metal-containing material containing the metal M. In this case, the metal-containing material 132 may or may not be provided on the substrate 130.

[0047] <An example of a plasma processing method> Fig. 3 is a flow chart showing an example of a plasma processing method (hereinafter also referred to as "method MT") according to one illustrative embodiment. As shown in Fig. 3, method MT includes step ST1 of providing a substrate and step ST2 of generating plasma. The processing in each step may be performed by the plasma processing apparatus 1 shown in Fig. 1. In the following, an example will be described in which a control unit 2 controls each part of the plasma processing apparatus 1 shown in Fig. 1 to perform method MT on a substrate W.

[0048] (Step ST1: Providing the substrate) In step ST1, a substrate W is provided 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 transfer arm, placed on a substrate support 11 by a lifter, and held by suction on the substrate support 11 as shown in FIG.

[0049] 4 is a diagram showing an example of a cross-sectional structure of a substrate W provided in step ST1. The substrate W has a film EF and a mask MK arranged on the film EF. The film EF may be formed on an undercoat film UF. The substrate W may be used for manufacturing a semiconductor device. The semiconductor device may include, for example, a semiconductor memory device such as a DRAM or a 3D-NAND flash memory.

[0050] In one embodiment, the undercoat film UF is a silicon wafer or an organic film, a dielectric film, a metal film, a semiconductor film, or the like, formed on a silicon wafer. In one embodiment, the undercoat film UF may be configured by stacking a plurality of films.

[0051] The film EF is a film to be etched by the present processing method. In one embodiment, the 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 including two or more of these films. For example, the silicon-containing film may be configured by alternately stacking a silicon oxide film and a silicon nitride film. For example, the silicon-containing film may be configured by alternately stacking a silicon oxide film and a polycrystalline silicon film. For example, the silicon-containing film may be a laminated film including a silicon nitride film, a silicon oxide film, and a polycrystalline silicon film. The silicon-containing film may be a film in which an element such as phosphorus, boron, or nitrogen is doped in a silicon oxide film, a silicon nitride film, a silicon carbonitride film, a polycrystalline silicon film, or a laminated film including two or more of these films. In one embodiment, the film EF is a carbon-containing film or a metal oxide film.

[0052] The mask MK has a pattern to be transferred to the film EF by etching. The mask MK may be a single-layer mask made of one layer, or may be a multi-layer mask made of two or more layers. As shown in FIG. 4, a sidewall S1 of the mask MK defines at least one opening OP on the film EF. The opening OP is a space on the film EF and is surrounded by the sidewall S1 of the mask MK. That is, the upper surface of the film EF has an area covered by the mask MK and an area exposed at the bottom of the opening OP.

[0053] The openings OP 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 MK may have a plurality of side walls that define a plurality of openings OP. The plurality of openings OP may each have a linear shape and be arranged at regular intervals to form a line and space pattern. Also, the plurality of openings OP may each have a hole shape and form an array pattern.

[0054] The mask MK may be appropriately selected depending on the film EF. In one embodiment, the mask MK is made of a material having an etching rate with respect to the plasma generated in step ST2 lower than that of the film EF.

[0055] In one embodiment, the mask MK is a carbon-containing mask. The carbon-containing mask is, for example, an amorphous carbon (ACL) film, a spin-on carbon (SOC) film, or a photoresist film. The ACL film may be doped with elements such as boron, arsenic, tungsten, and xenon.

[0056] In one embodiment, the mask MK is a metal-containing mask. In one example, the metal-containing mask includes at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, indium, gallium, and zinc. The metal-containing mask may include, for example, a carbide or silicide of the metal. In one embodiment, the metal-containing mask is a tungsten-containing film. The tungsten-containing film further includes, for example, tungsten and at least one selected from the group consisting of silicon, carbon, and nitrogen. In one example, the metal-containing mask includes at least one selected from the group consisting of tungsten carbide, tungsten silicide, WSiN, and WSiC. In one example, the metal-containing mask includes at least one selected from the group consisting of ruthenium, tungsten silicide, titanium nitride, molybdenum, and InGaZnO.

[0057] The undercoat film UF, the film EF, and the mask MK may each be formed by any method. For example, the undercoat film UF, the film EF, and the mask MK may be formed by a CVD method, an ALD method, a PVD method, a spin coating method, or the like. The mask MK may be formed by, for example, lithography. The opening OP of the mask MK may be formed by etching the mask MK. The undercoat film UF, the film EF, and the mask MK may each be a flat film, or may be a film having irregularities. The substrate W may further include another film under the undercoat film UF. In this case, a recess having a shape corresponding to the opening OP may be formed in the film EF and the undercoat film UF, and used as a mask for etching the other film.

[0058] At least a part of the process of forming the undercoat film UF, the film EF, and the mask MK of the substrate W may be performed in the chamber 10 as part of step ST1. For example, when the opening OP of the mask MK is formed by etching, the etching in step ST1 and the etching process in step ST2 described below may be performed consecutively in the chamber 10. In one embodiment, the substrate W may be provided in the chamber 10 after all or a part of the substrate W is formed in an apparatus or chamber outside the plasma processing apparatus 1.

[0059] In one embodiment, after the substrate W is provided to the central region 111a of the substrate support 11, the substrate support 11 is controlled to a given temperature by a temperature control module. In one example, controlling the temperature of the substrate support 11 to a given temperature includes setting the temperature of the heat transfer fluid flowing through the flow path 1110a or the heater temperature to a given temperature or to a temperature different from the given temperature. The timing at which the heat transfer fluid starts to flow through the flow path 1110a may be before or after the substrate W is placed on the substrate support 11, or may be the same as the substrate W. The temperature of the substrate support 11 may be controlled to a given temperature before the 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 a given temperature.

[0060] In one embodiment, instead of controlling the substrate support 11 to a given temperature, the substrate W may be controlled to a given temperature. Controlling the temperature of the substrate W to a given 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 a given temperature or to a temperature different from the given temperature.

[0061] In one embodiment, the temperature of the substrate support 11 or the substrate W may be controlled to a given temperature set in step ST1 during the subsequent processing in step ST2.

[0062] (Step ST2: Plasma generation) In step ST2, plasma is generated from a processing gas. First, the processing gas is supplied from the gas supply unit 20 into the chamber 10. The processing gas contains hydrogen fluoride (HF) gas.

[0063] In one embodiment, the process gas includes a noble gas, such as Ar gas, He gas, Kr gas, or Xe gas, or an inert gas, such as N2 gas. In one example, the noble gas is Xe gas.

[0064] In one embodiment, HF gas may have the largest flow rate (partial pressure) of the process gas, excluding inert gases. In one example, the flow rate of HF gas may be 50 vol.% or more, 60 vol.% or more, 70 vol.% or more, 80 vol.% or more, 90 vol.% or more, or 95 vol.% or more, based on the total flow rate of the process gas (if the process gas includes an inert gas, the flow rate of all gases excluding the inert gas). The flow rate of HF gas may be less than 100 vol.%, 99.5 vol.% or less, 98 vol.% or less, or 96 vol.% or less, based on the total flow rate of the process gas. In one example, the flow rate of HF gas is 70 vol.% or more and 96 vol.% or less, based on the total flow rate of the process gas.

[0065] In one embodiment, the process gas includes a phosphorus-containing gas. In one embodiment, the phosphorus-containing gas is a halogenated phosphorus gas. The halogenated phosphorus gas may be, for example, a phosphorus fluoride gas containing fluorine as a halogen element, such as PF3 gas or PF5 gas. In one embodiment, the halogenated phosphorus gas may be a phosphorus chloride gas containing chlorine as a halogen element, such as PCl3 gas or PCl5 gas. In one embodiment, the halogenated phosphorus gas may be a gas containing bromine or iodine as a halogen element, such as PBr3 gas, PBr5 gas, or PI3 gas. In one embodiment, the halogenated phosphorus gas may be a gas containing two or more halogen elements, such as PClF2 gas, PCl2F gas, or PCl2F3 gas. In one embodiment, the halogenated phosphorus gas may be an oxyhalogenated phosphorus gas, which may be an oxyfluorinated phosphorus gas or an oxychlorinated phosphorus gas. For example, the halogenated phosphorus gas may be POF3 gas, POCl3 gas, POF2Cl2 gas, POFCl2 gas, or POF2Cl gas. In one embodiment, the flow rate of the phosphorus-containing gas contained in the processing gas is 20 vol % or less, 10 vol % or less, or 5 vol % or less of the total flow rate of the processing gas.

[0066] In one embodiment, the process gas includes a carbon-containing gas. In one embodiment, the carbon-containing gas is a fluorocarbon gas and / or a hydrofluorocarbon gas. The fluorocarbon gas may be, for example, at least one selected from the group consisting of CF4 gas, C2F2 gas, C2F4 gas, C3F6 gas, C3F8 gas, C4F6 gas, C4F8 gas, and C5F8 gas. The hydrofluorocarbon gas may be, for example, CHF3 gas, CH2F2 gas, CH3F gas, C2HF5 gas, C2H2F4 gas, C2H3F3 gas, C2H4F2 gas, C3HF7 gas, C3H2F2 gas, C3H2F4 gas, C3H2F6 gas, C3H3F5 gas, C4H2F6 gas, C4H5F5 gas, C4H2F8 gas, C5H2F6 gas, C5H2F 10 The carbon-containing gas may be at least one selected from the group consisting of C5H3F7 gas and C5H3F7 gas. In one embodiment, the carbon-containing gas is a linear gas having an unsaturated bond. Examples of such gases include C3F6 (hexafluoropropene) gas, C4F8 (octafluoro-1-butene, octafluoro-2-butene) gas, C3H2F4 (1,3,3,3-tetrafluoropropene) gas, C4H2F6 (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas, C4F8O (pentafluoroethyl trifluorovinyl ether) gas, CF3COF gas (1,2,2,2-tetrafluoroethane-1-one), CHF2COF (difluoroacetic acid fluoride) gas, and COF2 (carbonyl fluoride) gas. In one embodiment, the carbon-containing gas may be a gas containing carbon and a halogen other than fluorine, a gas containing carbon, fluorine and a halogen other than fluorine, or a gas containing carbon and two halogens different from fluorine. x H y F z X wHere, X is a halogen other than fluorine, x and w are integers of 1 or more, and y and z are integers of 0 or more. Such a gas may be, for example, at least one selected from the group consisting of CCl4, CH2Cl2, CHCl3, CF2Cl2, CH2ClF, CHCl2F, CBr2F2, C2F5Br, CF3I, C2F5I, and C3F7I.

[0067] In one embodiment, the process gas further includes a halogen-containing gas other than fluorine. In one embodiment, the halogen-containing gas other than fluorine is a chlorine-containing gas, a bromine-containing gas, and / or an iodine-containing gas. In one example, the chlorine-containing gas is at least one gas selected from the group consisting of Cl2, SiCl2, SiCl4, CCl4, SiH2Cl2, Si2Cl6, CH2Cl2, CHCl3, SO2Cl2, BCl3, PCl3, PCl5, and POCl3. In one example, the bromine-containing gas is at least one gas selected from the group consisting of Br2, HBr, CBr2F2, C2F5Br, PBr3, PBr5, POBr3, and BBr3. In one example, the iodine-containing gas is at least one gas selected from the group consisting of HI, CF3I, C2F5I, C3F7I, IF5, IF7, I2, and PI3. In one example, the halogen-containing gas other than fluorine may be at least one selected from the group consisting of Cl2 gas, Br2 gas, and HBr gas. In one example, the halogen-containing gas other than fluorine is Cl2 gas or HBr gas.

[0068] In one embodiment, the process gas further comprises a metal-containing gas. In one embodiment, the metal-containing gas is a gas containing at least one metal (metal M) selected from the group consisting of tungsten, molybdenum, ruthenium, and titanium. In one embodiment, the metal-containing gas may be a gas containing metal M and a halogen. In one example, the metal-containing gas is WF2 gas, WF4 gas, WF5 gas, WF6 gas, WCl2 gas, WCl4 gas, WCl5 gas, WCl6 gas, MoF4 gas, MoCl6 gas, TiCl4 gas, etc.

[0069] In one embodiment, the process gas further includes an oxygen-containing gas. The oxygen-containing gas is, for example, at least one gas selected from the group consisting of O2, CO, CO2, H2O, and H2O2. In one example, the oxygen-containing gas is an oxygen-containing gas other than H2O, for example, at least one gas selected from the group consisting of O2, CO, CO2, and H2O2. The flow rate of the oxygen-containing gas may be adjusted according to the flow rate of other gases (for example, carbon-containing gas) contained in the process gas.

[0070] In one embodiment, the process gas may include a gas capable of generating hydrogen fluoride species (HF species) in plasma in place of a part or all of the HF gas. The HF species includes at least one of hydrogen fluoride gas, radicals, and ions.

[0071] The gas capable of generating HF species may be, for example, a hydrofluorocarbon gas. The hydrofluorocarbon gas may have a carbon number of 2 or more, 3 or more, or 4 or more. Examples of the hydrofluorocarbon gas include CH2F2 gas, C3H2F4 gas, C3H2F6 gas, C3H3F5 gas, C4H2F6 gas, C4H5F5 gas, C4H2F8 gas, C5H2F6 gas, C5H2F 10 The hydrofluorocarbon gas is at least one selected from the group consisting of CH2F2 gas, C3H2F4 gas, C3H2F6 gas, and C4H2F6 gas, for example.

[0072] The gas capable of generating HF species may be, for example, a mixed gas containing a hydrogen source and a fluorine source. The hydrogen source may be, for example, at least one selected from the group consisting of H2 gas, NH3 gas, H2O gas, H2O2 gas, and a hydrocarbon gas (CH4 gas, C3H6 gas, etc.). The fluorine source may be, for example, a fluorine-containing gas that does not contain carbon, such as NF3 gas, SF6 gas, WF6 gas, or XeF2 gas. The fluorine source may also be a fluorine-containing gas that contains carbon, such as a fluorocarbon gas and a hydrofluorocarbon gas. For example, the fluorocarbon gas may be at least one selected from the group consisting of CF4 gas, C2F2 gas, C2F4 gas, C3F6 gas, C3F8 gas, C4F6 gas, C4F8 gas, and C5F8 gas. In one example, the hydrofluorocarbon gas may be at least one selected from the group consisting of CHF3 gas, CH2F2 gas, CH3F gas, C2HF5 gas, and hydrofluorocarbon gases containing three or more C's (C3H2F4 gas, C3H2F6 gas, C4H2F6 gas, etc.).

[0073] Next, plasma is generated from the processing gas. This causes the substrate W to be plasma-processed. The plasma processing includes etching the film EF of the substrate W with plasma to form a recess (hereinafter also referred to as "etching processing"). The plasma processing also includes a process of sputtering the upper electrode with plasma to form a metal-containing film containing a metal M on the side wall of the recess (hereinafter also referred to as "deposition processing"). In one embodiment, in step ST2, the etching processing and the deposition processing may be performed alternately or simultaneously. When the etching processing and the deposition processing are performed simultaneously, there may be a period during which one is dominant over the other.

[0074] The etching process and the deposition process will be described below with reference to Fig. 5, Fig. 6A, and Fig. 6B. Fig. 5 is a diagram showing an example of a substrate W being processed in step ST2. Fig. 6A and Fig. 6B are diagrams showing an example of a formation position of a metal-containing film.

[0075] In one embodiment, the etching process may be performed as follows. First, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or at least one upper electrode of the shower head 13. This generates a high-frequency electric field between the shower head 13 and the substrate support 11, and plasma is generated from the processing gas in the chamber 10. Since the processing gas contains HF gas, active species of hydrogen fluoride (HF species) are generated in the plasma. In addition, a bias signal (hereinafter also referred to as a "second bias signal") is supplied to the lower electrode of the substrate support 11. The timing of starting the supply of the second bias signal may be simultaneous with or different from the timing of starting the supply of the source RF signal. The second bias signal may be a bias RF signal supplied from the second RF generating unit 31b. The second bias signal may be a bias DC signal supplied from the DC generating unit 32a. This causes the active species including the HF species in the plasma to be attracted to the substrate W, etching the film EF, and forming a recess RC as shown in FIG. 5. The recess RC is a space defined by the side wall S2 and the bottom BT of the film EF.

[0076] In one embodiment, the source RF signal and the second bias signal may both be continuous waves or pulse waves, or one may be a continuous wave and the other a pulse wave. When both the source RF signal and the second bias signal are pulse waves, the periods of both pulse waves may or may not be synchronized. When a bias DC signal is used as the second bias signal, the pulse wave may have a rectangular, trapezoidal, triangular, or combination thereof.

[0077] In one embodiment, the etching process may have an H1 period (third period) and an L1 period (fourth period). In the H1 period, the second bias signal is supplied at a signal level H1 (third signal level). In the L1 period, the second bias signal is supplied at a signal level L1 (fourth signal level) or is not supplied. The signal level L1 is lower than the signal level H1. In the H1 period, etching may be promoted compared to the L1 period. In the L1 period, etching may be suppressed compared to the H1 period. In one embodiment, the H1 period and the L1 period may be alternately repeated during the etching process. Note that, when the second bias signal is a bias RF signal, the signal level of the second bias signal may be the power level [W] of the bias RF signal, and when the second bias signal is a bias DC signal, the signal level may be the voltage level [V] of the bias DC signal.

[0078] In one embodiment, the deposition process may be performed as follows. First, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or at least one upper electrode of the shower head 13. This generates a high-frequency electric field between the shower head 13 and the substrate support 11, and plasma is generated from the processing gas in the chamber 10. Also, a first bias signal is supplied to the upper electrode of the shower head 13. The timing of starting the supply of the first bias signal may be the same as or different from the timing of starting the supply of the source RF signal. The first bias signal may be a second DC signal generated by the second DC generating unit 32b. The second DC signal may have a negative polarity. This causes ions in the plasma to be attracted to and collide with the surface of the shower head 13, which has a negative potential. Then, the metal-containing material 132 constituting the surface of the shower head 13 is sputtered (physical sputtering), and the metal M and secondary electrons are emitted into the plasma. The metal M falls onto the substrate W. This causes a metal-containing film MF containing the metal M to be formed on the side wall S2 of the recess RC, as shown in FIG. 5. In the etching process, the metal-containing film MF can function as a protective film for the sidewall S2 on which the metal-containing film MF is formed. The secondary electrons emitted into the plasma can contribute to improving the plasma density and neutralizing the charged state of the substrate W. This can improve the etching rate of the film EF and the perpendicularity of the ions incident on the substrate W.

[0079] In one embodiment, the first bias signal may be a bias RF signal. For example, in the plasma processing apparatus 1, the second RF generating unit 31b may be configured to be electrically connected to the upper electrode, and the bias RF signal generated by the second RF generating unit 31b may be supplied to the upper electrode, thereby sputtering the upper electrode.

[0080] In one embodiment, the thickness (film thickness) and / or position of the metal-containing film MF may be adjusted by controlling the signal level of the first bias signal. FIGS. 6A and 6B are examples in which the thickness (film thickness) and position of the metal-containing film MF are adjusted according to the magnitude of the signal level of the first bias signal. FIG. 6A is an example of the metal-containing film MF when the signal level of the first bias signal is X1. FIG. 6B is an example of the metal-containing film MF when the signal level of the first bias signal is X2 which is greater than X1. In the example shown in FIG. 6B where the signal level of the first bias signal is X2 (>X1), the amount of the metal-containing film MF formed on the sidewall S2 of the recess RC is larger than that in the example shown in FIG. 6A where the signal level is X1 (<X2). As a result, the depth (D2) at which the film thickness of the metal-containing film MF in the example shown in FIG. 6B becomes maximum and the maximum value (t2) of the film thickness are larger than the depth (D1) and the maximum value (t1) in the example shown in FIG. 6A. Note that the signal level of the first bias signal may be the power level [W] of the bias RF signal when the first bias signal is a bias RF signal, and may be the voltage level [V] of the bias DC signal when the second bias signal is a bias DC signal.

[0081] In one embodiment, the deposition process may have an H2 period (first period) and an L2 period (second period). In the H2 period, the first bias signal is supplied at a signal level H2 (first signal level). In the L2 period, the second bias signal is supplied at a signal level L2 (second signal level) or not supplied. The signal level L2 is lower than the signal level H2. In the H2 period, the formation of the metal-containing film MF can be promoted compared to the L2 period. In the L2 period, the formation of the metal-containing film MF can be suppressed compared to the H2 period. In one embodiment, during the deposition process, the H2 period and the L2 period may be alternately repeated.

[0082] In one embodiment, instead of or in addition to physical sputtering by supplying a first bias signal (bias DC signal or bias RF signal), reactive sputtering may be performed. For example, when the metal-containing material 132 constituting the surface of the shower head 13 contains tungsten, the processing gas may contain a chlorine-containing gas. Then, reactive sputtering may be performed using the processing gas or plasma generated from the processing gas. In this case, during the deposition process, tungsten in the metal-containing material 132 chemically bonds with chlorine in the processing gas or plasma and is released from the metal-containing material 132 into the atmosphere, and reactive sputtering progresses. As a result, tungsten falls onto the substrate W, and a metal-containing film MF containing a metal M can be formed on the side wall S2 of the recess RC.

[0083] FIG. 7 is a diagram for explaining an example of the process in step ST2. In the example shown in FIG. 7, the etching process deepens the recess RC as step ST2 progresses ("A" → "B" → "C" in FIG. 7), and the bottom of the recess RC reaches the undercoat film UR ("D" in FIG. 7). Step ST2 may be ended at the state of "D" in FIG. 7. Also, in the example shown in FIG. 7, the deposition process forms a metal-containing film EF on the side wall of the recess RC as step ST2 progresses ("A" → "B" → "C" in the figure). The metal-containing film EF contains a metal M. Since the metal M has low reactivity with HF species in the plasma, the metal-containing film MF has a higher etching resistance to the plasma than the film EF. That is, the metal-containing film MF functions as a protective film for the side wall S2 in the etching process in step ST2. This can prevent the side wall S2 in the portion where the metal-containing film MF is formed from being etched in the width direction and expanding to cause bowing. In addition, the surface of the shower head 13 exposed to the plasma is made of a metal-containing material that contains the metal M. Since the metal M has low reactivity with the HF species in the plasma, the HF species are prevented from reacting with the shower head 13 and being consumed. Since the partial pressure of the HF species in the plasma is prevented from decreasing, the etching rate of the film EF can be prevented from decreasing.

[0084] During the process of step ST2, the amount of metal content MF formed can be adjusted appropriately. For example, the amount of metal content MF formed can be adjusted by controlling the degree of sputtering (amount, time, number of times, etc.) of the upper electrode in the deposition process. Also, for example, the amount of metal content MF formed can be adjusted by controlling the degree of etching (amount, time, number of times, etc.) in the etching process. In the example shown in FIG. 7, the amount of metal content MF formed is adjusted to increase as the process progresses until a given period (for example, a period during which bowing is likely to occur) ("A" → "B" → "C" in FIG. 7). This can further suppress bowing. Also, in the example shown in FIG. 7, the amount of metal content MF formed is adjusted so that the metal content MF does not remain on the side wall at the end of step ST2 ("D" in FIG. 7).

[0085] In one embodiment, during step ST2, the etching process may be performed continuously or intermittently multiple times. In one embodiment, during step ST2, the deposition process may be performed continuously or intermittently multiple times. In one embodiment, the etching process and the deposition process during step ST2 may be synchronous or partially synchronous, or may not be synchronous. In one example, the etching process and the deposition process may be started simultaneously, or the deposition process may be started after the etching process is started. In one example, the etching process and the deposition process may be stopped simultaneously, or the etching process may be stopped after the deposition process is stopped. In one example, the etching process and the deposition process may be alternately and repeatedly performed.

[0086] As described above, method MT can suppress shape abnormalities due to etching.

[0087] <Modification> In one embodiment, the plasma processing apparatus 1 may be connected to a supply source of a precoat gas. For example, at least one of the gas sources 21 of the gas supply unit 20 may be a precoat gas. The precoat gas may be introduced into the chamber 10 from the gas supply unit 20 through the shower head 13.

[0088] In one embodiment, the precoat gas may be a metal-containing gas that includes a metal M. In one example, the metal-containing gas is WF2 gas, WF4 gas, WF5 gas, WF6 gas, WCl2 gas, WCl4 gas, WCl5 gas, WCl6 gas, MoF4 gas, MoCl6 gas, TiCl4 gas, etc.

[0089] In one embodiment, the plasma processing apparatus 1 may be connected to a source of cleaning gas. For example, at least one of the gas sources 21 of the gas supply unit 20 may be a cleaning gas. The cleaning gas may be introduced into the chamber 10 from the gas supply unit 20 through the showerhead 13.

[0090] In one embodiment, the cleaning gas may be a hydrogen-containing gas. In one embodiment, the hydrogen-containing gas includes at least one gas selected from the group consisting of hydrogen gas, a hydrocarbon gas, and a hydrofluorocarbon gas. In one embodiment, the cleaning gas may be a hydrogen-containing gas that does not contain fluorine. Examples of such gases include hydrogen gas and a hydrocarbon gas (for example, CH4 gas and C3H6 gas).

[0091] FIG. 8 is a flow chart according to another example of the method MT. In one embodiment, the method MT may include a step STA of forming a precoat before the step ST1. In the step STA, the above-mentioned precoat gas is introduced into the chamber 10, and a precoat containing the metal M is formed on the surface of the shower head 13 facing the substrate support 11 (the surface exposed to the plasma). In the step STA, plasma may be generated from the precoat gas. The precoat containing the metal M can be a source of the metal M emitted from the upper electrode in the deposition process in the step ST2. In addition, the precoat containing the metal M has low reactivity with the HF species in the plasma. Therefore, in the step ST2, the precoat functions as a protective film for the shower head 13 and can suppress the HF species from reacting with the shower head 13 and being consumed. When a precoat containing the metal M is formed on the shower head 13, the shower head 13 of the plasma processing apparatus 1 may or may not have the metal-containing material 132.

[0092] In one embodiment, the method MT may include a step STB of cleaning the inside of the chamber 10 after step ST2. In step STB, the above-mentioned cleaning gas is introduced into the chamber 10, and plasma is generated from the cleaning gas. Then, by-products and the like attached to components inside the plasma processing chamber 10 can be removed by active hydrogen species in the plasma. For example, when the processing gas in step ST2 includes a phosphorus-containing gas, the reaction product can include a phosphorus compound. The phosphorus compound can react with the active hydrogen species in the plasma in step STB and be volatilized as hydrogen phosphide (PH3) gas.

[0093] <Experiment> Next, an experiment performed to evaluate the method MT will be described. The present disclosure is not limited to the following experiment.

[0094] (Experiment 1) In experiment 1, the influence of the signal level of the first bias signal on the formation position and bowing of the metal-containing film was evaluated. In experiment 1, the method MT was performed on the substrate W using the plasma processing apparatus 1. The shower head 13 of the plasma processing apparatus 1 was made of a tungsten-containing material. The film EF of the substrate W was a silicon-containing film, and the mask MK was an amorphous carbon film. In step ST2, the processing gas contained HF gas, a phosphorus-containing gas, and a chlorine-containing gas. In step ST2, the etching process and the deposition process were performed simultaneously. In the deposition process, a second DC signal was used as the first bias signal. In experiment 1, the signal level (voltage level) of the second DC signal was changed to 0 [V], 100 [V], 300 [V], and 500 [V], and the position of the metal-containing film MF formed in the recess RC and the bowing of the recess RC were evaluated.

[0095] 9 and 10 are diagrams showing the results of Experiment 1. FIG. 9 is a diagram showing the relationship between the signal level of the second DC signal and the formation position of the metal-containing film. In FIG. 9, L [V] on the horizontal axis is the signal level (voltage level) of the second DC signal. MFD [nm] on the vertical axis is the formation position of the metal-containing film MF, specifically, the position where the film thickness of the metal-containing film MF is maximum (the distance from the boundary between the mask MK and the film EF). FIG. 10 is a diagram showing the relationship between the signal level of the second DC signal and bowing. In FIG. 10, L [V] on the horizontal axis is the signal level of the second DC signal. B / D [nm / μm] on the vertical axis is the ratio of the bowing dimension [nm] of the recess RC to the depth [μm] to the bottom of the recess RC.

[0096] As shown in Fig. 9, as the signal level of the second DC signal increased, the position at which the metal-containing film MF was formed became deeper. This is believed to be because, as the signal level increased, the amount of tungsten released by sputtering of the upper electrode increased, and the amount of the metal-containing film MF formed in the recess RC increased. Note that, when the signal level was zero, the metal-containing film MF was formed due to reactive sputtering caused by chlorine and the like derived from the chlorine-containing gas in the process gas.

[0097] As shown in Fig. 10, the bowing was improved as the signal level (voltage level) of the second DC signal in the deposition process of step ST2 increased. In particular, when the signal level of the second DC signal was 300 V or higher, the bowing was significantly improved.

[0098] (Experiments 2 and 3) In experiments 2 and 3, the effect of the showerhead material on the etching rate was evaluated. In experiment 2, the method MT was performed on three types of blanket substrates using the plasma processing apparatus 1, and the etching rate was evaluated. The partial pressure of the HF species in the chamber 10 during step ST2 was measured using a quadrupole mass spectrometer (QMS). A silicon oxide film, a silicon nitride film, and a photoresist film were formed on the three types of blanket substrates, respectively. The showerhead 13 of the plasma processing apparatus 1 was made of a tungsten-containing material. In step ST2, the processing gas contained HF gas and a phosphorus-containing gas. In step ST2, the etching process and the deposition process were performed simultaneously.

[0099] In experiment 3, a blanket substrate was etched and the etching rate was evaluated under the same conditions as in experiment 2, except that a showerhead made of silicon was used. The partial pressure of HF species in the chamber was also measured during etching.

[0100] FIG. 11 shows the results of Experiment 2 and Experiment 3. FIG. 11 shows the etching rates (nm / min) of the blanket films in Experiments 2 and 3. As shown in FIG. 11, the etching rates of the silicon oxide film and the silicon nitride film in Experiment 2 were both higher than those in Experiment 3. The partial pressure (P2) of the HF species in the chamber 10 in Experiment 2 was 19% higher than the partial pressure (P3) of the HF species in Experiment 3 (P2=P3+19). This is considered to be because the consumption of the HF species in the shower head was suppressed in Experiment 2 compared to Experiment 3. As a result, it is considered that the amount of HF species supplied to the silicon oxide film and the silicon nitride film in Experiment 2 was increased, and the etching rate was improved compared to Experiment 3. There was no significant difference in the etching rate of the photoresist film between Experiments 2 and 3.

[0101] (Experiments 4 and 5) In experiments 4 and 5, the effect of the shower head material on the etching shape was evaluated. In experiment 4, the method MT was performed on the substrate W using the plasma processing apparatus 1, and the shape of the recess RC after etching was evaluated. In experiment 4, the shower head 13 of the plasma processing apparatus 1 was made of a tungsten-containing material. The film EF of the substrate W was a silicon oxide film, and the mask MK was an amorphous carbon film. The opening OP of the mask MK had a hole shape in a planar view. In step ST2, the processing gas contained HF gas and a phosphorus-containing gas. In step ST2, the etching process and the deposition process were performed simultaneously.

[0102] In experiment 5, the substrate W was etched under the same conditions as in experiment 4, except that a showerhead made of silicon was used, and the shape of the recess RC after etching was evaluated.

[0103] The shape of the recessed portion RC in Experiment 4 was better than that in Experiment 5. Specifically, in Experiment 4, bowing of the recessed portion RC was suppressed, distortion of the recessed portion RC was improved, and the verticality of the etching was improved compared to Experiment 5. In addition, the circularity of the recessed portion RC in a plan view was improved in Experiment 4 compared to Experiment 5.

[0104] The embodiments of the present disclosure further include the following aspects.

[0105] (Appendix 1) 1. A plasma processing method for processing a substrate in a plasma processing apparatus, comprising: The plasma processing apparatus includes: A chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support, the upper electrode having a surface opposite the substrate support that includes a metal; a power source configured to provide a source RF signal to the substrate support or the upper electrode; The plasma processing method includes: (a) providing a substrate on the substrate support, the substrate including a membrane and a mask on the membrane; (b) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas; The step (b) includes etching the film on the substrate with the plasma to form a recess, and forming a metal-containing film containing the metal on a side wall of the recess. Plasma treatment method.

[0106] (Appendix 2) 2. The plasma processing method according to claim 1, wherein the metal includes at least one selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

[0107] (Appendix 3) 3. The plasma processing method of claim 1, wherein forming the metal-containing film includes providing a first bias signal to the upper electrode and sputtering the upper electrode.

[0108] (Appendix 4) 4. The plasma processing method according to claim 3, further comprising controlling a level of the first bias signal to adjust at least one of a thickness and a position of the metal-containing film formed on a side wall of the recess.

[0109] (Appendix 5) 5. The plasma processing method according to claim 3, wherein the first bias signal is a negative polarity bias DC signal.

[0110] (Appendix 6) 6. The plasma processing method according to claim 3, wherein the first bias signal is a bias RF signal different from the source RF signal.

[0111] (Appendix 7) 7. The plasma processing method according to any one of Appendix 3 to Appendix 6, wherein (b) includes a first period and a second period, and in the first period, the first bias signal is supplied at a first signal level, and in the second period, the first bias signal is not supplied or is supplied at a second signal level lower than the first signal level.

[0112] (Appendix 8) 8. The plasma processing method according to claim 7, wherein in (b), the first period and the second period are repeated alternately.

[0113] (Appendix 9) 9. The plasma processing method of any one of claims 1 to 8, wherein etching the film includes providing a second bias signal to the substrate support.

[0114] (Appendix 10) The plasma processing method of claim 9, wherein (b) includes a third period and a fourth period, and during the third period, the second bias signal is supplied to the substrate support at a third signal level, and during the fourth period, the second bias signal is not supplied to the substrate support or is supplied at a fourth signal level lower than the third level.

[0115] (Appendix 11) 11. The plasma processing method according to claim 10, wherein in (b), the third period and the fourth period are repeated alternately.

[0116] (Appendix 12) 12. The plasma processing method of claim 1, wherein the film on the substrate is a silicon-containing film.

[0117] (Appendix 13) 13. The plasma processing method of claim 1, wherein the processing gas includes a reactive gas, and forming the metal-containing film includes sputtering the upper electrode using the reactive gas or a plasma generated from the reactive gas.

[0118] (Appendix 14) 14. The plasma processing method of claim 1, wherein the processing gas further comprises a phosphorus-containing gas.

[0119] (Appendix 15) 15. The plasma processing method of claim 1, wherein the process gas further comprises a carbon-containing gas.

[0120] (Appendix 16) 16. The plasma processing method according to claim 1, wherein the processing gas further contains a halogen-containing gas other than fluorine.

[0121] (Appendix 17) 17. The plasma processing method of claim 1, wherein the processing gas further comprises a metal-containing gas, the metal-containing gas comprising at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

[0122] (Appendix 18) 18. The plasma processing method according to any one of Appendix 1 to Appendix 17, further comprising, before (a), a step of pre-coating a surface of the upper electrode facing the substrate support with a metal-containing material, the metal material containing at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

[0123] (Appendix 19) 1. A plasma processing method for processing a substrate in a plasma processing apparatus, comprising: The plasma processing apparatus includes: A chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support; a power source configured to provide a source RF signal to the substrate support or the upper electrode; The plasma processing method includes: (a) pre-coating a surface of the upper electrode facing the substrate support with a metal-containing material; (b) providing a substrate on the substrate support, the substrate including a membrane and a mask on the membrane; (c) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas; The step (c) includes etching the film on the substrate with the plasma to form a recess, and forming a metal-containing film containing the metal material on a side wall of the recess. Plasma treatment method.

[0124] (Appendix 20) A plasma processing apparatus comprising: A chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support, the upper electrode having a surface opposite the substrate support that includes a metal; a power source configured to provide a source RF signal to the substrate support or the upper electrode; A control unit, The control unit is (a) controlling providing a substrate on the substrate support, the substrate including a membrane and a mask on the membrane; (b) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including an HF gas; The step (b) includes etching the film on the substrate with the plasma to form a recess, and forming a metal-containing film containing the metal on a side wall of the recess. Plasma processing equipment.

[0125] 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]

[0126] REFERENCE SIGNS LIST 1: plasma processing apparatus, 2: control section, 10: plasma processing chamber, 10s: plasma processing space, 11: substrate support section, 13: shower head, 20: gas supply section, 31a: first RF generating section, 31b: second RF generating section, 32a: first DC generating section, 32b: second DC generating section, EF: film, MK: mask, OP: opening, RC: recess, UF: base film, W: substrate

Claims

1. 1. A plasma processing method for processing a substrate in a plasma processing apparatus, comprising: The plasma processing apparatus includes: A chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support, the upper electrode having a surface opposite the substrate support that includes a metal; a power source configured to provide a source RF signal to the substrate support or the upper electrode; The plasma processing method includes: (a) providing a substrate on the substrate support, the substrate including a membrane and a mask on the membrane; (b) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas; The step (b) includes: etching the film on the substrate with the plasma to form a recess; and forming a metal-containing film containing the metal on a side wall of the recess. Plasma treatment method.

2. 2. The plasma processing method according to claim 1, wherein the metal includes at least one selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

3. 2. The plasma processing method of claim 1, wherein forming the metal-containing film comprises providing a first bias signal to the upper electrode and sputtering the upper electrode.

4. 4. The plasma processing method according to claim 3, further comprising controlling a level of the first bias signal to adjust at least one of a thickness and a position of the metal-containing film formed on a side wall of the recess.

5. 4. The plasma processing method of claim 3, wherein the first bias signal is a negative polarity bias DC signal.

6. The plasma processing method of claim 3 , wherein the first bias signal is a bias RF signal different from the source RF signal.

7. 4. The plasma processing method of claim 3, wherein (b) includes a first period and a second period, in which the first bias signal is supplied at a first signal level during the first period, and in which the first bias signal is not supplied or is supplied at a second signal level lower than the first signal level during the second period.

8. The plasma processing method according to claim 7 , wherein in (b), the first period and the second period are alternately repeated.

9. The plasma processing method of claim 1 , wherein etching the film comprises providing a second bias signal to the substrate support.

10. 10. The plasma processing method of claim 9, wherein (b) includes a third period and a fourth period, and during the third period, the second bias signal is supplied to the substrate support at a third signal level, and during the fourth period, the second bias signal is not supplied to the substrate support or is supplied at a fourth signal level lower than the third level.

11. The plasma processing method according to claim 10 , wherein in (b), the third period and the fourth period are alternately repeated.

12. The plasma processing method according to claim 1 , wherein the film on the substrate is a silicon-containing film.

13. 2. The plasma processing method of claim 1, wherein the process gas includes a reactive gas, and forming the metal-containing film includes sputtering the upper electrode using the reactive gas or a plasma generated from the reactive gas.

14. The plasma processing method according to claim 1 , wherein the processing gas further contains a phosphorus-containing gas.

15. The plasma processing method of claim 1 , wherein the processing gas further includes a carbon-containing gas.

16. 12. The plasma processing method according to claim 1, wherein the processing gas further contains a halogen-containing gas other than fluorine.

17. 12. The plasma processing method according to claim 1, wherein the processing gas further contains a metal-containing gas, and the metal-containing gas contains at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

18. 12. The plasma processing method according to claim 1, further comprising, before the step (a), a step of pre-coating a surface of the upper electrode facing the substrate support with a metal-containing material, the metal material containing at least one metal selected from the group consisting of tungsten, molybdenum, ruthenium, titanium, samarium, and yttrium.

19. 1. A plasma processing method for processing a substrate in a plasma processing apparatus, comprising: The plasma processing apparatus includes: A chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support; a power source configured to provide a source RF signal to the substrate support or the upper electrode; The plasma processing method includes: (a) pre-coating a surface of the upper electrode facing the substrate support with a metal-containing material; (b) providing a substrate on the substrate support, the substrate including a membrane and a mask on the membrane; (c) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas; The step (c) includes etching the film on the substrate with the plasma to form a recess, and forming a metal-containing film containing the metal material on a side wall of the recess. Plasma treatment method.

20. A plasma processing apparatus comprising: A chamber; a substrate support disposed within the chamber; an upper electrode disposed opposite the substrate support, the upper electrode having a surface opposite the substrate support that includes a metal; a power source configured to provide a source RF signal to the substrate support or the upper electrode; A control unit, The control unit is (a) controlling providing a substrate on the substrate support, the substrate including a membrane and a mask on the membrane; (b) supplying a source RF signal from the power source to the substrate support or the upper electrode to generate plasma from a process gas including HF gas; The step (b) includes: etching the film on the substrate with the plasma to form a recess; and forming a metal-containing film containing the metal on a side wall of the recess. Plasma processing equipment.

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