Etching method and plasma processing apparatus

Abstract

The invention provides a technique for suppressing shape abnormality of etching. The invention provides an etching method. The method includes: (a) a step of preparing a substrate including a film to be etched having a recessed portion and a mask having an opening exposing the recessed portion and disposed on the film to be etched; (b) a step for forming a metal-containing film on the side wall of the recess using a first plasma formed from a first processing gas containing a metal-containing gas containing at least one metal selected from the group consisting of ruthenium, tungsten, molybdenum, and titanium; and (c) a step for etching the film to be etched in the recess using a second plasma formed from a second processing gas containing a hydrogen fluoride gas.

Description

Technical Field

[0001] The exemplary embodiments of this disclosure relate to etching methods and plasma processing apparatus. Background Technology

[0002] Patent document 1 discloses a technique for simultaneously suppressing bending and etching a silicon-containing film.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-21546 Summary of the Invention

[0006] The technical problem the invention aims to solve

[0007] This disclosure provides a technique for suppressing etched shape anomalies.

[0008] Technical solutions for solving technical problems

[0009] In one exemplary embodiment of this disclosure, an etching method is provided, performed in a plasma processing apparatus having a chamber, the etching method comprising the following steps: (a) a step of preparing a substrate including an etch target film having recesses and a mask disposed on the etch target film, the mask having an opening exposing the recesses; (b) a step of forming a metal-containing film on the sidewalls of the recesses using a first plasma formed from a first processing gas containing a metal-containing gas, the metal-containing gas containing at least one metal selected from ruthenium, tungsten, molybdenum and titanium; and (c) a step of etching the etch target film in the recesses using a second plasma formed from a second processing gas containing hydrogen fluoride gas.

[0010] Invention Effects

[0011] According to an exemplary embodiment of this disclosure, a technique for suppressing etched shape anomalies can be provided. Attached Figure Description

[0012] Figure 1 This is a diagram illustrating an example of the structure of a plasma processing device.

[0013] Figure 2 This is a diagram illustrating a structural example of a capacitively coupled plasma processing device.

[0014] Figure 3 This is a diagram used to illustrate an example of an arc bend.

[0015] Figure 4 This is a flowchart illustrating an example of this method.

[0016] Figure 5 This is a diagram showing an example of the cross-sectional structure of the substrate W provided in process ST11.

[0017] Figure 6 This is a diagram showing an example of the cross-sectional structure of the substrate W after process ST12.

[0018] Figure 7 This is a diagram showing an example of the cross-sectional structure of the substrate W after process ST2.

[0019] Figure 8 This is a diagram illustrating an example of the cross-sectional structure of substrate W during process ST3. Detailed Implementation

[0020] The following describes various embodiments of this disclosure.

[0021] In one exemplary embodiment, an etching method is provided, performed in a plasma processing apparatus having a chamber, the etching method comprising the following steps: (a) a step of preparing a substrate including an etch target film having recesses and a mask disposed on the etch target film, the mask having an opening that exposes the recesses; (b) a step of forming a metal-containing film on the sidewalls of the recesses using a first plasma formed from a first processing gas containing a metal-containing gas, the metal-containing gas containing at least one metal selected from ruthenium, tungsten, molybdenum and titanium; and (c) a step of etching the etch target film in the recesses using a second plasma formed from a second processing gas containing hydrogen fluoride gas.

[0022] In one exemplary embodiment, the second processing gas further comprises a metal-containing gas, in which a metal-containing film is formed on the sidewall of the recess and the film to be etched is etched in the recess.

[0023] In one exemplary implementation, the cycle of steps (b) and (c) is repeated multiple times.

[0024] In one exemplary embodiment, the second processing gas further comprises a phosphorus-containing gas.

[0025] In one exemplary embodiment, in (c), the temperature of the substrate or substrate support portion of the supporting substrate is controlled to be below 0°C.

[0026] In one exemplary embodiment, an etching method is provided for performance in a plasma processing apparatus having a chamber, the etching method comprising: (a) a step of preparing a substrate including an etch target film having recesses and a mask disposed on the etch target film having openings that expose the recesses; and (b) a step of forming a metal-containing film on the sidewalls of the recesses using a plasma generated from a processing gas comprising a metal-containing gas and a hydrogen fluoride gas, and etching the etch target film in the recesses, wherein the metal-containing gas comprises at least one metal selected from ruthenium, tungsten, molybdenum, and titanium.

[0027] In one exemplary embodiment, the processing gas also includes a phosphorus-containing gas.

[0028] In one exemplary embodiment, in (b), the temperature of the substrate support portion of the substrate or the supporting substrate is controlled to be below 0°C.

[0029] In one exemplary embodiment, the film to be etched is a silicon-containing film, a carbon-containing film, or a metal oxide film.

[0030] In one exemplary embodiment, the etched target film comprises at least one selected from silicon oxide film, silicon nitride film, silicon oxynitride film, silicon carbonitride film, and polycrystalline silicon film, as well as a laminated film comprising at least two of the above films.

[0031] In one exemplary embodiment, the mask comprises at least one metal selected from ruthenium, tungsten, molybdenum, titanium, indium, gallium, and zinc.

[0032] In one exemplary embodiment, the mask is a carbon-containing film.

[0033] In one exemplary embodiment, the substrate has an etch stop film beneath the etch target film, the etch stop film comprising at least one metal selected from ruthenium, tungsten, molybdenum, titanium, indium, gallium, and zinc.

[0034] In one exemplary embodiment, a plasma processing apparatus is provided, having a chamber and a control unit, the control unit performing: (a) control of preparing a substrate within the chamber, the substrate including an etch target film having a recess and a mask having an opening exposing the recess and disposed on the etch target film; (b) control of forming a metal-containing film on the sidewall of the recess using a first plasma formed in the chamber by a first processing gas containing a first metal-containing gas, the metal-containing gas containing at least one metal selected from ruthenium, tungsten, molybdenum and titanium; and (c) control of etching the etch target film in the recess using a second plasma formed in the chamber by a second processing gas containing hydrogen fluoride gas.

[0035] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in each drawing, the same or identical elements are labeled with the same reference numerals, and repeated descriptions are omitted. Unless otherwise specified, positional relationships such as up, down, left, and right are described based on the positional relationships shown in the drawings. The scale of the drawings does not represent actual ratios, and actual ratios are not limited to those shown in the drawings.

[0036] <Structural Example of a Plasma Processing System>

[0037] Figure 1 This is a diagram illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to the gas supply unit 20 (described later), and the gas outlet is connected to the exhaust system 40 (described later). The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0038] The plasma generation unit 12 is configured to generate plasma from at least one process gas supplied to the plasma processing space. The plasma formed in the plasma processing space can be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR), helicon wave plasma (HWP), or surface wave plasma (SWP), etc. Alternatively, various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC (Direct Current) plasma generation units, can be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes RF (radio frequency) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0039] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 is capable of controlling various elements of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control actions by reading a program from the storage unit 2a2 and executing the read program. The program may be pre-stored in the storage unit 2a2 or retrieved via a medium when needed. The retrieved program is stored in the storage unit 2a2 and read and executed by the processing unit 2a1 from the storage unit 2a2. 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 RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may also communicate with the plasma processing device 1 via a communication line such as LAN (Local Area Network).

[0040] <Structural Example of a Capacitively Coupled Plasma Processing Device>

[0041] Hereinafter, a structural example of a capacitively coupled plasma processing device, which is one example of plasma processing device 1, will be described. Figure 2 This is a diagram illustrating a structural example of a capacitively coupled plasma processing device.

[0042] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Additionally, the plasma processing apparatus 1 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 nozzle 13. The substrate support 11 is disposed within the plasma processing chamber 10. The nozzle 13 is disposed above the substrate support 11. In one embodiment, the nozzle 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the nozzle 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The nozzle 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0043] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 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 portion 111 surrounds the central region 111a of the main body portion 111 when viewed from above. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 in such a way that it surrounds the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as an annular support surface for supporting the ring assembly 112.

[0044] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b disposed within the ceramic component 1111a. The ceramic component 1111a has a central region 111a. In one embodiment, the ceramic component 1111a also has an annular region 111b. Furthermore, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may also have an annular region 111b. In this case, the ring assembly 112 may be disposed on either the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component. Additionally, at least one RF / DC electrode coupled to the RF power supply 31 and / or DC power supply 32 (described later) may also be disposed within the ceramic component 1111a. In this case, at least one RF / DC electrode serves as a lower electrode. When a bias RF signal and / or DC signal (described later) are supplied to at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Furthermore, the conductive components of the base 1110 and at least one RF / DC electrode may also function as multiple lower electrodes. Additionally, the electrostatic electrode 1111b may also function as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

[0045] The ring assembly 112 includes one or more annular components. In one embodiment, the one or more annular components 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 ring is formed of an insulating material.

[0046] Additionally, the substrate support 11 may also include a temperature control 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 control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path 1110a. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are disposed within the ceramic component 1111a of the electrostatic chuck 1111. Furthermore, the substrate support 11 may also include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0047] The nozzle 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The nozzle 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlets 13c. The process gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the plurality of gas inlets 13c. Additionally, the nozzle 13 includes at least one upper electrode. Furthermore, in addition to the nozzle 13, the gas inlet may also include one or more side gas injectors (SGIs) mounted on one or more openings formed in the sidewall 10a.

[0048] The gas supply unit 20 may also 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 nozzle 13 via a corresponding flow controller 22. Each flow controller 22 may, for example, include a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include at least one flow modulation device for modulating or pulsed the flow rate of at least one process gas.

[0049] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. Plasma is thus 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 generation unit 12. Furthermore, by supplying a bias RF signal to at least one lower electrode, a bias potential can be generated on the substrate W, introducing ionic components from the formed plasma into the substrate W.

[0050] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is configured to be coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit 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 10MHz to 150MHz. In one embodiment, the first RF generation unit 31a may also be configured to generate multiple source RF signals with 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.

[0051] The second RF generation unit 31b is configured to couple to at least one lower electrode via at least one impedance matching circuit 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 that 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 generation unit 31b may also be configured to generate multiple bias RF signals with different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Additionally, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0052] Alternatively, 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 generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is connected to at least one lower electrode to generate a first DC signal. The generated first DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit 32b is connected to at least one upper electrode to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0053] In various embodiments, the first and second DC signals can also be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses can have rectangular, trapezoidal, triangular, or combinations thereof pulse waveforms. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses based on the DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Therefore, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses can have positive or negative polarity. Additionally, the sequence of voltage pulses can also include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. Furthermore, the first and second DC generation units 32a and 32b can also be provided based on the RF power supply 31, and the first DC generation unit 32a can also replace the second RF generation unit 31b.

[0054] The exhaust system 40 can be connected, for example, to a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted using the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0055] <An example of an arc curve>

[0056] As one of the shape anomalies in plasma etching, bends are known. A bend is a phenomenon where the opening size of a portion of the sidewall of an etched recess is larger than the opening size of the top of the recess. The portion with a bend appears, for example, barrel-shaped when viewed in cross-section. Bends are thought to be caused by the cutting of a portion of the sidewall of the recess by ions or other particles bouncing off a mask.

[0057] Figure 3 This is a diagram used to illustrate an example of a bow. Figure 3 This is an example of a cross-sectional structure where a recess RC is formed by etching the etch target film EF of a substrate W using a mask MK with an opening OP. In this example, when the bottom BT of the recess RC reaches the base film UF, a barrel-shaped bend (Bow) is formed on the upper side (low aspect ratio region) of the recess RC. The opening size of the recess RC that forms the bend is larger than the opening size on the middle to lower side (medium aspect ratio region to high aspect ratio region) of the recess RC. Furthermore, there are cases where the bend is formed not only on the upper side of the recess RC but also on the middle to lower side.

[0058] An etching method of an exemplary embodiment of this disclosure (hereinafter also referred to as "this method") is capable of suppressing such curvature. Hereinafter, it will be described with reference to the accompanying drawings.

[0059] <An example of this method>

[0060] Figure 4 This is a flowchart illustrating an example of the method. The method includes a step ST1 of preparing a substrate, a step ST2 of forming a metal-containing film in a recess, and a step ST3 of etching the recess. Step ST1 includes: a step ST11 of providing a substrate W; and a step ST12 of etching the substrate W to form the recess. In one embodiment, the processing in each step can be carried out in a plasma processing apparatus 1 (see...). Figure 1 , Figure 2 The control unit 2 controls the capacitively coupled plasma processing device 1 (see reference 1) in the following example. Figure 2 Each part of the process executes this method.

[0061] (Step ST1: Substrate preparation)

[0062] In step ST1, a substrate with a recess is prepared. First, in step ST11, the substrate W is provided into the plasma processing space of the plasma processing apparatus 1 for 10 seconds. Then, in step ST12, a recess is formed on the substrate W.

[0063] In process ST11, the substrate W is disposed in the central region 111a of the substrate support portion 11 and held in the substrate support portion 11 by an electrostatic chuck 1111. Figure 5 This is a diagram illustrating an example of the cross-sectional structure of the substrate W provided in process ST11. (See diagram below.) Figure 5 As shown, the substrate W includes an etch target film EF and a mask MK disposed on the etch target film EF. In one embodiment, the etch target film EF may be formed on a base film UF. The substrate W can be used for the fabrication of semiconductor devices. Semiconductor devices include, for example, semiconductor memory devices such as DRAM and 3D-NAND flash memory.

[0064] In one embodiment, the substrate film UF is a silicon wafer, an organic film, a dielectric film, a metal film, a semiconductor film, etc., formed on the silicon wafer. In one embodiment, the substrate film UF may include an etch stop film. In one embodiment, the etch stop film contains at least one metal selected from tungsten, molybdenum, ruthenium, titanium, indium, gallium, and zinc. The etch stop film may, for example, contain carbides or silicides of the aforementioned metals. The etch stop film may, for example, be a tungsten-containing film. The etch stop film may further contain tungsten and at least one selected from silicon, carbon, and nitrogen. In one example, the etch stop film contains at least one selected from tungsten carbide, tungsten silicide, WSiN, and WSiC. The etch stop film may, for example, contain at least one selected from ruthenium, tungsten silicide, titanium nitride, molybdenum, and InGaZnO.

[0065] In one embodiment, the substrate film UF can be formed by stacking multiple films. When the substrate film UF is composed of multiple films, an etch stop film can be formed on the top layer of the substrate film UF. That is, the etch stop film can be configured to contact the etch target film EF.

[0066] The etching target film EF is the film that is etched in this method. The etching target film EF can be composed of a single film, or it can be composed of multiple films stacked together.

[0067] In one embodiment, the etched target film EF is a silicon-containing film. In one example, the silicon-containing film is a silicon oxide film, a silicon nitride film, a silicon carbonitride film, a polycrystalline silicon film, or a stacked film comprising two or more of these films. For example, the silicon-containing film can be formed by alternately stacking silicon oxide films and silicon nitride films. For example, the silicon-containing film can be formed by alternately stacking silicon oxide films and polycrystalline silicon films. For example, the silicon-containing film can also be a stacked film comprising silicon nitride films, silicon oxide films, and polycrystalline silicon films.

[0068] In one embodiment, the etched target film EF is a carbon-containing film. In one example, the carbon-containing film is an amorphous carbon film.

[0069] In one embodiment, the etched target film EF is a metal oxide film. In one example, the metal oxide film is a zinc oxide film or a tin oxide film.

[0070] The mask MK has a pattern that is transferred to the etched target film EF through etching. The mask MK can be a single-layer mask consisting of one layer or a multi-layer mask consisting of two or more layers. For example... Figure 5 As shown, the sidewall SS1 of the mask MK defines at least one opening OP on the etched film EF. The opening OP is a space on the etched film EF surrounded by the sidewall SS1 of the mask MK. That is, the upper surface of the etched film EF has an area covered by the mask MK and an area exposed at the bottom of the opening OP.

[0071] When viewing the substrate W from above, i.e., from... Figure 5 When viewing the substrate W from above and below, the opening OP can have any shape. This shape can be, for example, a circle, an ellipse, a rectangle, a line, or a combination of more than one of these. The mask MK can also have multiple sidewalls, which define multiple opening OPs. The multiple opening OPs can also each have a line shape, arranged at certain intervals to form a pattern of lines and space. Alternatively, the multiple opening OPs can each have a hole shape, forming an array pattern.

[0072] The mask MK can be appropriately selected based on the target film EF to be etched. In one embodiment, the mask MK is formed of a material whose etching rate is lower than that of the target film EF relative to the plasma formed in processes ST12 and ST3.

[0073] In one embodiment, the mask MK is a carbon-containing mask or a metal-containing mask. A carbon-containing mask is, in one example, an amorphous carbon (ACL) film, a spin-coated carbon (SOC) film, or a photoresist film. The ACL film may also be doped with elements such as boron, arsenic, tungsten, or xenon. A metal-containing mask is, in one example, a metal-containing film containing the same metal as the aforementioned etch stop film.

[0074] The substrate film UF, the etch target film EF, and the mask MK can each be formed by any method. For example, the substrate film UF, the etch target film EF, and the mask MK can be formed by CVD, ALD, PVD, spin coating, etc. The mask MK can also be formed by photolithography, for example. Furthermore, the opening OP of the mask MK can be formed by etching the mask MK. The substrate film UF, the etch target film EF, and the mask MK can each be a flat film, or they can be films with irregularities. In addition, the substrate W can have other films beneath the substrate film UF. In this case, recesses of a shape corresponding to the opening OP can also be formed in the etch target film EF and the substrate film UF, serving as a mask for etching these other films.

[0075] At least a portion of the processes for forming the substrate film UF, etching the target film EF, and the mask MK can be performed within the plasma processing space for 10 seconds as part of step ST11. For example, in the case where the opening OP of the mask MK is formed by etching, the etching in step ST11 and the etching in step ST12 can be performed continuously within the plasma processing space for 10 seconds. In one embodiment, the substrate W can be provided to the plasma processing space for 10 seconds after all or part of the substrate W has been formed in a device or chamber outside the plasma processing apparatus 1.

[0076] 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 predetermined temperature using a temperature control module. In one example, controlling the temperature of the substrate support 11 to a predetermined temperature includes setting the temperature of the heat transfer fluid flowing in the flow path 1110a, the heater temperature to a predetermined temperature, or a temperature different from the predetermined temperature. Furthermore, the moment when the heat transfer fluid begins to flow in the flow path 1110a can be before, after, or simultaneously with the substrate W being placed in the substrate support 11. Additionally, the temperature of the substrate support 11 can be controlled to a predetermined temperature before process ST1. That is, the substrate W can be provided to the substrate support 11 after the temperature of the substrate support 11 has been controlled to a predetermined temperature. In one embodiment, the predetermined temperature is below 0°C, below -10°C, below -20°C, below -30°C, below -40°C, below -50°C, below -60°C, or below -70°C. In one embodiment, the predetermined temperature is above -100°C.

[0077] In one embodiment, the substrate W may be controlled at a predetermined temperature instead of the substrate support 11. Controlling the temperature of the substrate W to a predetermined temperature includes setting the temperature of the heat transfer fluid flowing in the substrate support 11, the flow path 1110a, and / or the heater temperature to a predetermined temperature, or to a temperature different from the predetermined temperature.

[0078] In step ST12, a recess is formed in the etching target film EF. First, a processing gas is supplied from the gas supply unit 20 into the plasma processing space for 10 seconds. The processing gas can be selected in such a way that the etching target film EF has a sufficient selectivity relative to the mask MK. The processing gas can be the same as or different from the second processing gas used in the etching of step ST3 described later.

[0079] In one embodiment, the process gas may contain a fluorine-containing gas. In one example, the fluorine-containing gas is hydrogen fluoride (HF), a fluorocarbon gas, or a hydrofluorocarbon gas. In another embodiment, the process gas may further contain one or more gases selected from phosphorus-containing gases, carbon-containing gases, oxygen-containing gases, halogen-containing gases other than fluorine-containing gases, and inert gases. The types of gases constituting the process gas and the flow rates (partial pressures) of each gas can be constant during the processing in step ST12, or they can be varied as etching proceeds.

[0080] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the nozzle 13. This generates a high-frequency electric field between the nozzle 13 and the substrate support 11, and plasma is generated by the processing gas within the plasma processing space for 10 seconds. In one embodiment, a bias signal may be supplied to the lower electrode of the substrate support 11. This attracts reactive species such as ions and free radicals in the plasma to the substrate W, and the etchable film EF is etched to form a recess. The bias signal may be a bias RF signal supplied from the second RF generation unit 31b. Alternatively, the bias signal may be a bias DC signal supplied from the DC generation unit 32a.

[0081] In one embodiment, during the processing in step ST12, the temperature of the substrate support 11 or the substrate W can be controlled to a predetermined temperature set in step ST11.

[0082] Figure 6 This is a diagram illustrating an example of the cross-sectional structure of the substrate W after process ST12. (See diagram below.) Figure 6 As shown, through the processing in step ST12, the portion of the etched object film EF exposed at the opening OP is etched in the depth direction ( Figure 6 The film is etched from top to bottom to form a recess RC. The recess RC is the space defined by the sidewall SS2 and bottom BT of the etched film EF.

[0083] In one embodiment, process ST12 may end based on the dimensions (depth, opening size, aspect ratio) and / or etching time related to the recess RC. In one embodiment, process ST12 may end just before the recess RC forms a bend. In one embodiment, the depth D1 of the recess RC after process ST12 may be less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, less than 3%, or less than 1% of the final etching depth (e.g., depth D2 to the base film UF).

[0084] As described above, in step ST1, a substrate W comprising an etchable film EF having a recess RC and a mask MK having an opening OP is prepared on the substrate support portion 11 of the plasma processing chamber 10. Alternatively, the substrate W can be prepared by providing it to the substrate support portion 11 of the plasma processing apparatus 1 after the recess RC is formed on the substrate W in an external device or chamber of the plasma processing apparatus 1.

[0085] (Process ST2: Formation of metal film)

[0086] In process ST2, a metal-containing film is formed in the recess RC of the etched target film EF.

[0087] First, a first processing gas containing a metal-containing gas is supplied from the gas supply unit 20 to the plasma processing space for 10 seconds. The metal-containing gas is a gas containing at least one metal selected from ruthenium, tungsten, molybdenum, and titanium (hereinafter also referred to as "metal M"). In one embodiment, the metal-containing gas is a gas containing ruthenium and a halogen. In one example, the metal-containing gas can be RuO3 gas, RuO4 gas, RuF5 gas, or RuF6 gas. In one embodiment, the metal-containing gas can be a gas containing tungsten, molybdenum, or titanium and a halogen. In one example, the metal-containing gas can be WF2 gas, WF4 gas, WF5 gas, WF6 gas, WCl2 gas, WCl4 gas, WCl5 gas, WCl6 gas, MoF4 gas, MoCl6 gas, TiCl4 gas, etc. In one embodiment, the first processing gas also contains an inert gas. The inert gas can be, for example, an inert gas such as Ar gas, He gas, and Kr gas, or nitrogen gas.

[0088] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the nozzle 13. This generates a high-frequency electric field between the nozzle 13 and the substrate support 11, generating a first plasma from the first processing gas within the plasma processing space for 10 seconds. At this time, a bias signal may not be supplied to the lower electrode of the substrate support 11. Alternatively, a bias signal may be supplied to the lower electrode of the substrate support 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 11 in steps ST12 and ST3. Furthermore, the bias signal may be a bias RF signal or a bias DC signal.

[0089] In one embodiment, during the processing in step ST2, the temperature of the substrate support 11 or the substrate W can be controlled to be the same as the given temperature set in step ST11, or it can be controlled to be a different temperature (e.g., a temperature higher than the given temperature).

[0090] Figure 7This is a diagram illustrating an example of the cross-sectional structure of the substrate W after process ST2. (See diagram below.) Figure 7 As shown, a metal-containing film MF is formed in the recess RC through the processing in step ST2. The metal-containing film MF is a film containing metal M originating from the first processing gas. In one embodiment, the metal-containing film MF is continuously formed from the top TP1 of the mask MK to the sidewall SS1 of the mask MK and the sidewall SS2 of the etched film EF. In one embodiment, the metal-containing film MF can be formed on the entire sidewall SS2 of the etched film EF, or on a portion (e.g., the upper part) of the sidewall SS2. In one embodiment, the metal-containing film MF can be formed on the sidewall SS2 from the upper part of the recess RC toward the bottom BT in a bottom-down manner. During the etching of the recess RC in step ST3, the metal-containing film MF can provide protection to the sidewall SS2 on which the metal-containing film MF is formed.

[0091] (Process ST3)

[0092] In process ST3, the recess RC of the etching target film EF is etched. First, a second processing gas containing HF gas is supplied from the gas supply unit 20 into the plasma processing space for 10 seconds.

[0093] In one embodiment, the flow rate (partial pressure) of HF gas in the second processing gas, excluding the inert gas, can be maximized. In one example, the flow rate of HF gas relative to the total flow rate of the second processing gas (or, if the second processing gas includes an inert gas, the flow rate of all gases except that inert gas) can be 50% or more by volume, 60% or more by volume, 70% or more by volume, 80% or more by volume, 90% or more by volume, or 95% or more by volume. Alternatively, the flow rate of HF gas relative to the total flow rate of the second processing gas can be less than 100% by volume, less than 99.5% by volume, less than 98% by volume, or less than 96% by volume. In one example, the flow rate of HF gas relative to the total flow rate of the second processing gas is 70% or more by volume and less than 96% by volume.

[0094] In one embodiment, the second processing gas further comprises one or more gases selected from phosphorus-containing gases, carbon-containing gases, oxygen-containing gases, halogen-containing gases other than fluorine-containing gases, and inert gases.

[0095] In one embodiment, the phosphorus-containing gas is a phosphorus halide gas. For example, the phosphorus halide gas may be phosphorus fluoride containing fluorine as a halogen element, such as PF3 or PF5 gas. In one embodiment, the phosphorus halide gas may be phosphorus chloride gas containing chlorine as a halogen element, such as PCl3 or PCl5 gas. In one embodiment, the phosphorus halide gas may be a gas containing bromine or iodine as halogen elements, such as PBr3, PBr5, or PI3 gas. In one embodiment, the phosphorus halide gas may be a gas containing two or more halogen elements, such as PClF2, PCl2F, or PCl2F3 gas. In one embodiment, the phosphorus halide gas may be phosphorus fluoride oxidizing gas or phosphorus chloride oxidizing gas. For example, the phosphorus halide gas may be POF3, POCl3, POF2Cl2, POFCl2, or POF2Cl gas. In one embodiment, the flow rate of the phosphorus-containing gas in the second processing gas is 20% or less, 10% or less, or 5% or less of the total flow rate of the second processing gas.

[0096] 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 CF4, C2F2, C2F4, C3F6, C3F8, C4F6, C4F8, and C5F8. The hydrofluorocarbon gas may be, for example, CHF3, CH2F2, CH3F, C2HF5, C2H2F4, C2H3F3, C2H4F2, C3HF7, C3H2F2, C3H2F4, C3H2F6, C3H3F5, C4H2F6, C4H5F5, C4H2F8, C5H2F6, and C5H2F6. 10 At least one of the following is selected: gas and C5H3F7 gas. In one embodiment, the carbon-containing gas is a straight-chain gas with unsaturated bonds. Examples of such gases include C3F6 (hexafluoropropylene), C4F8 (octafluoro-1-butene, octafluoro-2-butene), C3H2F4 (1,3,3,3-tetrafluoropropylene), C4H2F6 (trans-1,1,4,4,4-hexafluoro-2-butene), C4F8O (pentafluoroethyl trifluorovinyl ether), CF3COF (1,2,2,2-tetrafluoroethane-1-one), CHF2COF (difluoroacetyl fluoride), and COF2 (carbonyl fluoride).

[0097] In one embodiment, the oxygen-containing gas is, for example, at least one gas selected from 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 O2, CO, CO2, and H2O2. The flow rate of the oxygen-containing gas can be adjusted according to the flow rate of other gases (e.g., carbon-containing gases) contained in the second processed gas.

[0098] In one embodiment, the halogen-containing gas other than fluorine can be a chlorine-containing gas, a bromine-containing gas, and / or an iodine-containing gas. As an example of a chlorine-containing gas, it can be at least one gas selected from Cl2, SiCl2, SiCl4, CCl4, SiH2Cl2, Si2Cl6, CHCl3, SO2Cl2, BCl3, PCl3, PCl5, and POCl3. As an example, a bromine-containing gas can be at least one gas selected from Br2, HBr, CBr2F2, C2F5Br, PBr3, PBr5, POBr3, and BBr3. As an example, an iodine-containing gas can be at least one gas selected from HI, CF3I, C2F5I, C3F7I, IF5, IF7, I2, and PI3. As an example, the halogen-containing gas other than fluorine can be at least one gas selected from Cl2, Br2, and HBr. As an example, the halogen-containing gas other than fluorine is either Cl2 or HBr.

[0099] In one embodiment, the inert gas is an inert gas such as Ar, He, or Kr, and / or nitrogen.

[0100] In one embodiment, the second processing gas may replace part or all of the HF gas with a gas capable of generating hydrogen fluoride species (HF species) in the plasma. The HF species includes at least one of hydrogen fluoride gas, free radicals, and ions.

[0101] Gases capable of generating HF can be, for example, hydrofluorocarbons. Hydrofluorocarbons can have 2 or more, 3 or more, or 4 or more carbon atoms. As examples, hydrofluorocarbons can be CH₂F₂, C₃H₂F₄, C₃H₂F₆, C₃H₃F₅, C₄H₂F₆, C₄H₅F₅, C₄H₂F₈, C₅H₂F₆, C₅H₂F₆, and C₅H₂F₆. 10 The gas is selected from C5H3F7 and other gases. As an example, the hydrofluorocarbon gas is at least one selected from CH2F2, C3H2F4, C3H2F6 and C4H2F6.

[0102] The gas capable of generating HF can be, for example, a mixture of a hydrogen source and a fluorine source. The hydrogen source can be, for example, at least one selected from H2 gas, NH3 gas, H2O gas, H2O2 gas, and hydrocarbon gases (CH4 gas, C3H6 gas, etc.). The fluorine source can be, for example, a carbon-free fluorine-containing gas such as NF3 gas, SF6 gas, WF6 gas, or XeF2 gas. Alternatively, the fluorine source can also be a carbon-containing fluorine-containing gas such as a fluorocarbon gas or a hydrofluorocarbon gas. In one example, the fluorocarbon gas can be at least one selected from CF4 gas, C2F2 gas, C2F4 gas, C3F6 gas, C3F8 gas, C4F6 gas, C4F8 gas, and C5F8 gas. As an example, the hydrofluorocarbon gas can be at least one selected from CHF3 gas, CH2F2 gas, CH3F gas, C2HF5 gas, and hydrofluorocarbon gases containing three or more types of carbon (C3H2F4 gas, C3H2F6 gas, C4H2F6 gas, etc.).

[0103] In one embodiment, during the processing in step ST3, the type and flow rate (partial pressure) of the gas constituting the second processing gas can be constant, or they can be changed as etching proceeds.

[0104] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the nozzle 13. This generates a high-frequency electric field between the nozzle 13 and the substrate support 11, and a second plasma is generated by the second processing gas within the plasma processing space for 10 seconds. In one embodiment, a bias signal may be supplied to the lower electrode of the substrate support 11. This attracts active species such as ions and free radicals in the second plasma to the substrate W, further etching the recess RC of the etching target film EF in the depth direction. The bias signal may be a bias RF signal supplied from the second RF generation unit 31b. Alternatively, the bias signal may be a bias DC signal supplied from the DC generation unit 32a.

[0105] In one embodiment, during the processing in step ST3, the temperature of the substrate support 11 or the substrate W can be controlled to a predetermined temperature set in step ST11.

[0106] Figure 8 This is a diagram illustrating an example of the cross-sectional structure of substrate W during process ST3. (See diagram below.) Figure 8As shown, the recess RC is further etched in the depth direction through process ST3. As described above, in process ST2, a metal-containing film MF containing metal M (ruthenium, tungsten, molybdenum, and / or titanium) is formed on the sidewall SS2 of the recess RC. The metal-containing film MF containing metal M has low reactivity with the active species of hydrogen fluoride in the second plasma. The etching resistance of the metal-containing film MF to the second plasma is higher than that of the etch target film EF. The metal-containing film MF functions as a protective film against the sidewall SS2 during etching in process ST3. Thus, the sidewall SS2 where the metal-containing film is formed can be suppressed from etching in the width direction ( Figure 8 The etching extends and creates a bend in the left-right direction. Furthermore, when a metal-containing film MF is also formed on the mask MK, the metal-containing film MF also functions as a protective film for the mask MK. This improves the selectivity of etching the target film EF relative to etching the mask MK.

[0107] The etching process ST3 stops when a given stopping condition is met, and the method ends. The stopping condition can be, for example, the etching time, or the depth of the recess RC. The aspect ratio of the recess RC at the end of etching can be, for example, 20 or more, or 30 or more, 40 or more, 50 or more, or 100 or more.

[0108] According to this method, during etching in step ST3, it is possible to suppress the formation of arc bending in the recess RC of the etched film EF. That is, this method can suppress the generation of shape anomalies caused by etching.

[0109] <Variation Example>

[0110] This method can be modified in various ways without departing from the scope and spirit of this disclosure.

[0111] In one embodiment, steps ST2 and ST3 can be performed repeatedly in this method. That is, steps ST2 and ST3 can be performed as a cycle, and this cycle can be repeated multiple times. In this case, the formation of the metal-containing film MF on the sidewall SS2 of the recess RC and the etching in the depth direction of the recess RC are performed alternately and repeatedly. As a result, arc bending can be further suppressed.

[0112] In one embodiment, the second processing gas used in step ST3 may further include a metal-containing gas containing metal M. In this case, in step ST3, the formation of the metal-containing film MF on the sidewall SS2 of the recess RC and the etching in the depth direction of the recess RC are performed simultaneously. This further suppresses arcing.

[0113] In one embodiment, after performing step ST11, step ST3 can be performed without performing step ST2, and the second processing gas used in step ST3 contains a metal-containing gas containing metal M. In this case, in step ST3, a metal-containing film MF is formed on the sidewall SS2 of the recess RC, and the recess RC is simultaneously etched in the depth direction. This suppresses arcing.

[0114] In one embodiment, step ST1 may further include a step of forming a carbon-containing film on the sidewall SS2 of the recess RC after forming the recess RC in step ST12. The formation of the carbon-containing film can be performed by various methods, such as plasma CVD, thermal CVD, or ALD. Metals M (ruthenium, tungsten, molybdenum, and / or titanium) tend to readily deposit on the carbon-containing film. By pre-forming a carbon-containing film on the sidewall SS2 of the recess RC, the formation of a metal-containing film MF on the sidewall SS2 of the recess RC can be facilitated in step ST2 and step ST3 of the above-described variation.

[0115] The embodiments disclosed herein also include the following methods.

[0116] (Note 1)

[0117] An etching method, an etching method performed in a plasma processing apparatus having a chamber, comprising:

[0118] (a) A process of preparing a substrate, the substrate comprising: an etchable film having recesses; and a mask having an opening that exposes the recesses, disposed on the etchable film;

[0119] (b) A step of forming a metal-containing film on the sidewall of the recess using a first plasma formed from a first processing gas containing a metal-containing gas, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum, and titanium; and

[0120] (c) A process of etching the etchable film in the recess using a second plasma formed by a second processing gas containing hydrogen fluoride gas.

[0121] (Note 2)

[0122] According to the etching method described in Appendix 1, the second processing gas further includes the metal-containing gas, and in step (c), a metal-containing film is formed on the sidewall of the recess, and the film to be etched is etched in the recess.

[0123] (Note 3)

[0124] According to the etching method described in Appendix 1 or Appendix 2, the cycle including step (b) and step (c) is repeated multiple times.

[0125] (Note 4)

[0126] According to any one of the etching methods described in Appendix 1 to 3, the second processing gas further comprises a phosphorus-containing gas.

[0127] (Note 5)

[0128] According to any one of the etching methods described in Appendix 1 to 4, in (c), the temperature of the substrate or the substrate support portion supporting the substrate is controlled to be below 0°C.

[0129] (Note 6)

[0130] An etching method, an etching method performed in a plasma processing apparatus having a chamber, comprising:

[0131] (a) A process of preparing a substrate, the substrate comprising: an etchable film having recesses; and a mask having an opening that exposes the recesses, disposed on the etchable film;

[0132] (b) A process of forming a metal-containing film on the sidewall of the recess using a plasma generated from a processing gas containing a metal-containing gas and a hydrogen fluoride gas, and etching the film in the recess, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum and titanium.

[0133] (Note 7)

[0134] According to the etching method described in Appendix 6, the processing gas further includes a phosphorus-containing gas.

[0135] (Note 8)

[0136] According to the etching method described in Appendix 6 or 7, in (b), the temperature of the substrate or the substrate support portion supporting the substrate is controlled to be below 0°C.

[0137] (Note 9)

[0138] According to any one of the etching methods described in Appendix 1 to 8, wherein the film to be etched is a silicon-containing film, a carbon-containing film, or a metal oxide film.

[0139] (Postscript 10)

[0140] According to any one of the etching methods described in Appendix 1 to 9, the film to be etched includes at least one selected from silicon oxide film, silicon nitride film, silicon oxynitride film, silicon carbonitride film and polycrystalline silicon film, and a laminated film containing at least two of the films therein.

[0141] (Postscript 11)

[0142] According to any one of the etching methods described in Appendix 1 to Appendix 10, the mask comprises at least one metal selected from ruthenium, tungsten, molybdenum, titanium, indium, gallium and zinc.

[0143] (Postscript 12)

[0144] The etching method described in any one of Appendix 1 to Appendix 11, wherein the mask is a carbon-containing film.

[0145] (Postscript 13)

[0146] According to any one of the etching methods described in Appendices 1 to 12, the substrate has an etching stop film under the etch target film, the etching stop film comprising at least one metal selected from ruthenium, tungsten, molybdenum, titanium, indium, gallium and zinc.

[0147] (Postscript 14)

[0148] A plasma processing apparatus includes a chamber and a control unit, characterized in that:

[0149] The control unit performs:

[0150] (a) Control of preparing a substrate in a cavity, wherein the substrate comprises: an etchable film having a recess; and a mask having an opening that exposes the recess, disposed on the etchable film;

[0151] (b) In the chamber, control is achieved by forming a metal-containing film on the sidewall of the recess using a first plasma formed from a first processing gas containing a metal-containing gas, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum, and titanium; and

[0152] (c) In the chamber, the etching of the etchable film is controlled by a second plasma formed by a second processing gas containing hydrogen fluoride gas in the recess.

[0153] (Postscript 15)

[0154] A plasma processing apparatus includes a chamber and a control unit, characterized in that:

[0155] The control unit performs:

[0156] (a) Control of substrate preparation, wherein the substrate comprises: an etchable film having recesses; and a mask having openings exposing the recesses, disposed on the etchable film.

[0157] (b) Using plasma generated from a processing gas containing a metal-containing gas and a hydrogen fluoride gas, a metal-containing film is formed on the sidewall of the recess, and the film to be etched is etched in the recess, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum and titanium.

[0158] The above embodiments are described for illustrative purposes only and are not intended to limit the scope of this disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure. For example, some components of one embodiment can be added to other embodiments. Furthermore, some components of one embodiment can be replaced with corresponding components of other embodiments.

[0159] Explanation of reference numerals in the attached figures

[0160] 1...Plasma processing device

[0161] 2... Control Department

[0162] 10...Plasma processing chamber

[0163] 10s... Plasma processing space

[0164] 11...Substrate support section

[0165] 13...spray head

[0166] 20……Gas Supply Department

[0167] 31a……First RF Generation Department

[0168] 31b……Second RF Generation Department

[0169] 32a……First DC Generation Unit

[0170] EF...Etching the target film

[0171] MK...mask

[0172] OP...open

[0173] RC...concave

[0174] UF…basement membrane

[0175] W... substrate.

Claims

1. An etching method for use in a plasma processing apparatus having a chamber, characterized in that, include: (a) A process of preparing a substrate, the substrate comprising: an etchable film having recesses; and a mask having an opening that exposes the recesses, disposed on the etchable film; (b) A step of forming a metal-containing film on the sidewall of the recess using a first plasma formed from a first processing gas containing a metal-containing gas, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum, and titanium; and (c) A process of etching the etchable film in the recess using a second plasma formed by a second processing gas containing hydrogen fluoride gas.

2. The etching method as described in claim 1, characterized in that: The second processing gas also includes the metal-containing gas, and in step (c), a metal-containing film is formed on the sidewall of the recess, and the film to be etched is etched in the recess.

3. The etching method as described in claim 1, characterized in that: The cycle including steps (b) and (c) is repeated multiple times.

4. The etching method as described in claim 1, characterized in that: The second processing gas also includes phosphorus-containing gas.

5. The etching method as described in claim 1, characterized in that: In step (c), the temperature of the substrate or the substrate support portion supporting the substrate is controlled to be below 0°C.

6. An etching method for use in a plasma processing apparatus having a chamber, characterized in that, include: (a) A step of preparing a substrate, the substrate comprising: an etchable film having recesses; and a mask having openings that expose the recesses, disposed on the etchable film; and (b) A process of forming a metal-containing film on the sidewall of the recess using a plasma generated from a processing gas containing a metal-containing gas and a hydrogen fluoride gas, and etching the film in the recess, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum and titanium.

7. The etching method as described in claim 6, characterized in that: The processed gas also includes phosphorus-containing gas.

8. The etching method as described in claim 6, characterized in that: In (b), the temperature of the substrate or the substrate support portion supporting the substrate is controlled to be below 0°C.

9. The etching method according to any one of claims 1 to 8, characterized in that: The etched film is a silicon-containing film, a carbon-containing film, or a metal oxide film.

10. The etching method according to any one of claims 1 to 8, characterized in that: The etched target film includes at least one selected from silicon oxide film, silicon nitride film, silicon oxynitride film, silicon carbonitride film, and polycrystalline silicon film, as well as a laminated film containing at least two of these films.

11. The etching method according to any one of claims 1 to 8, characterized in that: The mask contains at least one metal selected from ruthenium, tungsten, molybdenum, titanium, indium, gallium, and zinc.

12. The etching method according to any one of claims 1 to 8, characterized in that: The mask is a carbon-containing film.

13. The etching method according to any one of claims 1 to 8, characterized in that: The substrate has an etching stop film beneath the etch target film, the etching stop film comprising at least one metal selected from ruthenium, tungsten, molybdenum, titanium, indium, gallium and zinc.

14. A plasma processing apparatus comprising a chamber and a control unit, characterized in that: The control unit performs: (a) Control of substrate preparation within the chamber, wherein, The substrate includes: an etchable film having recesses; and a mask having openings that expose the recesses, disposed on the etchable film; (b) In the chamber, control is achieved by forming a metal-containing film on the sidewall of the recess using a first plasma formed from a first processing gas containing a metal-containing gas, wherein the metal-containing gas contains at least one metal selected from ruthenium, tungsten, molybdenum, and titanium; and (c) In the chamber, the etching of the etchable film is controlled by a second plasma formed by a second processing gas containing hydrogen fluoride gas in the recess.

Images