JP2024129801A - Etching method, plasma processing apparatus, and substrate processing system - Google Patents

Abstract

To provide a technology to suppress etching shape anomalies.SOLUTION: An etching method is provided. This method includes (a) a step for providing a substrate having a stacked film containing at least two different silicon-containing films and a mask on the stacked film, (b) a step for etching the stacked film using plasma generated from a first process gas to form a recess in the stacked film, and (c) a step for supplying hydrogen fluoride to the recesses of the stacked film.SELECTED DRAWING: Figure 3

Description

Exemplary embodiments of the present disclosure relate to an etching method, a plasma processing apparatus, and a substrate processing system.

Patent document 1 discloses a technique for etching a laminated film by generating plasma from a processing gas containing a CF-based gas and oxygen gas.

International Publication No. 2014/069559

This disclosure provides technology to suppress shape abnormalities in etching.

In one exemplary embodiment of the present disclosure, an etching method is provided that includes the steps of: (a) providing a substrate having a stacked film including at least two different silicon-containing films and a mask on the stacked film; (b) etching the stacked film using plasma generated from a first process gas to form a recess in the stacked film; and (c) supplying hydrogen fluoride to the recess in the stacked film.

According to one exemplary embodiment of the present disclosure, a technology can be provided that suppresses shape abnormalities in etching.

FIG. 1 is a diagram for explaining a configuration example of a plasma processing apparatus. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. 1 is a flow chart illustrating an example of the method. 2 is a diagram showing an example of a cross-sectional structure of a substrate W provided in a process ST1. FIG. 13 is a diagram showing an example of a cross-sectional structure of the substrate W after being processed in step ST2. FIG. 13 is a diagram showing an example of a cross-sectional structure of the substrate W after being processed in step ST3. FIG. 1 is a graph showing an example of an adsorption equilibrium pressure curve of hydrogen fluoride. 1 is a diagram for explaining an example of the configuration of a substrate processing system PS1. 2 is a diagram for explaining a configuration example of a substrate processing system PS2. FIG.

Each embodiment of the present disclosure is described below.

In one exemplary embodiment, an etching method is provided that includes the steps of: (a) providing a substrate having a stacked film including at least two different silicon-containing films and a mask on the stacked film; (b) etching the stacked film using a plasma generated from a first process gas to form a recess in the stacked film; and (c) supplying hydrogen fluoride to the recess in the stacked film.

In one exemplary embodiment, the laminated film includes at least two selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film.

In one exemplary embodiment, the laminated film is composed of multiple alternating layers of silicon oxide films and silicon nitride films.

In one exemplary embodiment, the mask is a carbon-containing or metal-containing film.

In one exemplary embodiment, the first process gas includes hydrogen fluoride gas.

In one exemplary embodiment, the first process gas includes at least one selected from the group consisting of hydrogen fluoride gas, hydrofluorocarbon gas, and a mixture of a hydrogen-containing gas and a fluorine-containing gas.

In one exemplary embodiment, the first process gas further comprises a phosphorus-containing gas.

In one exemplary embodiment, the first process gas further comprises at least one gas selected from the group consisting of a carbon-containing gas, an oxygen-containing gas, and a metal-containing gas.

In one exemplary embodiment, at the end of (b), the recess has a first opening dimension and a second opening dimension that is different from the first opening dimension, alternating along the depth direction of the recess.

In one exemplary embodiment, the difference between the first and second aperture dimensions is 0.2 nm or more.

In one exemplary embodiment, (a) includes disposing a substrate in a first chamber, (b) includes supplying a first process gas into the first chamber to generate a plasma, and (c) includes supplying a second process gas including hydrogen fluoride gas into the first chamber.

In one exemplary embodiment, (c) includes the steps of: (c1) controlling the temperature of the substrate or the substrate support supporting the substrate to a first temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a first pressure; and (c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a second pressure, where the second temperature is higher than the first temperature and/or the second pressure is lower than the first pressure.

In one exemplary embodiment, (c) includes a step of (c1) controlling the temperature of the substrate or the substrate support part supporting the substrate to a first temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a first pressure, and a step of (c2) after (c1), controlling the temperature of the substrate or the substrate support part to a second temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a second pressure, in which in a graph showing an adsorption equilibrium pressure curve of hydrogen fluoride with the horizontal axis representing temperature and the vertical axis representing pressure, the first temperature and the first pressure are located in a first region above the adsorption equilibrium pressure curve, and the second temperature and the second pressure are located in a second region below the adsorption equilibrium pressure curve.

In one exemplary embodiment, (a) includes placing a substrate in a first chamber, (b) includes supplying a first process gas into the first chamber to generate a plasma, and (c) includes transferring the substrate from the first chamber to a second chamber different from the first chamber and supplying a second process gas including hydrogen fluoride gas into the second chamber.

In one exemplary embodiment, the temperature of the substrate or the substrate support supporting the substrate in (c) is controlled to a temperature lower than the temperature of the substrate or the substrate support supporting the substrate in (b).

In one exemplary embodiment, the second process gas further comprises a phosphorus-containing gas.

In one exemplary embodiment, (a) includes disposing a substrate in a first chamber, (b) includes supplying a first process gas into the first chamber to generate a plasma, and (c) includes transporting the substrate outside the first chamber and supplying a process liquid including hydrogen fluoride to the substrate outside.

In one exemplary embodiment, the treatment liquid includes dihydrofluoric acid (DHF) or buffered hydrofluoric acid (BHF).

In one exemplary embodiment, (a) includes placing a substrate in a first chamber of a plasma processing system, (b) includes supplying a first process gas into the first chamber to generate a plasma, and (c) includes transferring the substrate to a substrate processing apparatus outside the plasma processing system and supplying hydrogen fluoride to a recess in the stack film in the substrate processing apparatus.

In one exemplary embodiment, the method further includes a step of setting the condition (c) based on data indicating the shape of the recess in the laminated film.

In one exemplary embodiment, the conditions include at least one selected from the group consisting of the pressure of a chamber in which the substrate is housed, the temperature of the substrate or a substrate support that supports the substrate, and the flow rate of hydrogen fluoride gas.

In one exemplary embodiment, (c) includes (c3) supplying hydrogen fluoride to the recess of the laminated film under first conditions, and (c4) supplying hydrogen fluoride to the recess of the laminated film under second conditions different from the first conditions.

In one exemplary embodiment, the second condition differs from the first condition in at least one selected from the group consisting of the pressure of the chamber in which the substrate is housed, the temperature of the substrate or the substrate support that supports the substrate, and the flow rate of the hydrogen fluoride gas.

In one exemplary embodiment, a plasma processing apparatus is provided that has a chamber, a plasma generating unit, a gas supplying unit, and a control unit, and the control unit (a) controls the chamber to provide a substrate having a laminated film including at least two different silicon-containing films and a mask on the laminated film, (b) controls the plasma generating unit to etch the laminated film using plasma generated from a first processing gas in the chamber to form a recess in the laminated film, and (c) controls the gas supplying unit to supply a second processing gas including hydrogen fluoride gas to the recess in the laminated film in the chamber.

In one exemplary embodiment, a substrate processing system is provided that has a first chamber, a plasma generating unit, a second chamber, a gas supply unit, and a control unit, and the control unit (a) controls the first chamber to provide a substrate having a stacked film including at least two different silicon-containing films and a mask on the stacked film, (b) controls the first chamber to etch the stacked film using plasma generated from a first process gas by the plasma generating unit to form recesses in the stacked film, and (c) controls the substrate to be transported from the first chamber to the second chamber, and the second chamber to supply a second process gas including hydrogen fluoride gas to the recesses in the stacked film by the gas supply unit.

Each embodiment of the present disclosure will be described in detail below with reference to the drawings. Note that the same or similar elements in each drawing will be given the same reference numerals, and duplicated explanations will be omitted. Unless otherwise specified, the positional relationships such as up, down, left, right, etc. will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not indicate the actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

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

The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Also, various types of plasma generating units may be used, including AC (Alternating Current) plasma generating units and DC (Direct Current) plasma generating units. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include 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.

The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various steps described in this 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 configured as a system external to the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 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 RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), a SSD (Solid State Drive), or a combination of these. The communication interface 2a3 may communicate with each element of the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

Below, an example of the configuration of a capacitively coupled plasma processing apparatus is described as an example of the plasma processing apparatus 1. Figure 2 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus.

The capacitively coupled plasma processing apparatus 1 includes a control unit 2, a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

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 a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

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. At least one RF/DC electrode coupled to an RF power source 31 and/or a DC power source 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF/DC electrode functions as a lower electrode. When a bias RF signal and/or a DC signal, which will be described later, is supplied to the at least one RF/DC electrode, the RF/DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF/DC electrode may function as multiple lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Thus, the substrate support 11 includes at least one lower electrode.

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.

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

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.

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 to the showerhead 13 via a respective flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and/or at least one upper electrode. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power supply 31 can function as at least a part of the plasma generating unit 12. In addition, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

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

The second RF generator 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 lower frequency than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are provided 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.

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 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.

In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and/or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating 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 within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power source 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

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.

<Example of Etching Method>
3 is a flow chart showing an example of an etching method (hereinafter also referred to as "the method") according to an exemplary embodiment. As shown in FIG. 3, the method includes a step ST1 of providing a substrate, a step ST2 of etching a laminated film on the substrate, and a step ST3 of supplying hydrogen fluoride to a recess in the substrate. In one embodiment, the processes in each step may be performed in a plasma processing apparatus 1 (see FIGS. 1 and 2). In the following example, the method is performed by a control unit 2 controlling each part of a capacitively coupled plasma processing apparatus 1 (see FIG. 2).

(Step ST1: Providing a substrate)
In step ST1, a substrate W is provided in a plasma processing space 10s of the plasma processing apparatus 1. The substrate W is placed in a central region 111a of the substrate support 11 and held on the substrate support 11 by an electrostatic chuck 1111.

Figure 4 is a diagram showing an example of the cross-sectional structure of the substrate W supplied in process ST1. As shown in Figure 4, the substrate W has a laminated film FS and a mask MK. In one embodiment, the laminated film FS and the mask MK are formed on an undercoat film UF. That is, the substrate W may be formed by laminating the undercoat film UF, the laminated film FS, and the mask MK in this order. In one embodiment, the substrate W is used in the manufacture of semiconductor devices. Semiconductor devices include, for example, semiconductor memory devices such as 3D-NAND flash memories and DRAMs.

In one embodiment, the base 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. The base film UF may be composed of multiple films stacked together.

The laminated film FS is a film to be etched by the method. The laminated film FS has at least two different silicon-containing films. In one embodiment, the laminated film FS has at least two silicon-containing films with different compositions. In one embodiment, the laminated film FS may be configured by alternately stacking a silicon oxide film SF1 and a silicon nitride film SF2 as shown in FIG. 4. In one embodiment, the laminated film FS may be configured by alternately stacking a silicon oxide film and a polycrystalline silicon film. In one embodiment, the laminated film FS may be configured by stacking a silicon nitride film, a silicon oxide film, and a polycrystalline silicon film in a given order. In one embodiment, the laminated film FS may be configured by alternately stacking a silicon oxide film and a silicon carbonitride film. In one embodiment, the laminated film FS may be configured by stacking a silicon oxide film, a silicon nitride film, and a silicon carbonitride film in a given order. Note that silicon-containing films such as silicon oxide films, silicon nitride films, and polycrystalline silicon films may contain impurities such as phosphorus, boron, or nitrogen.

The mask MK may be formed of a material having a lower etching rate for the plasma generated in step ST2 than the laminated film FS. In one embodiment, the mask MK is a carbon-containing film or a metal-containing film. The carbon-containing film 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. The metal-containing film includes, for example, at least one metal selected from the group consisting of tungsten, molybdenum, titanium, ruthenium, samarium, and yttrium. The metal-containing film may include, for example, at least one metal selected from the group consisting of tungsten carbide (WC), tungsten silicide (WSi), WSiN, and WSiC. The mask MK may be a single-layer mask consisting of one film, or may be a multilayer mask consisting of two or more laminated films.

As shown in FIG. 4, the mask MK defines at least one opening OP on the laminated film FS. The opening OP is a space above the laminated film FS and is surrounded by the sidewall of the mask MK. That is, the upper surface of the laminated film FS has an area covered by the mask MK and an area exposed at the bottom of the opening OP.

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

Each film constituting the substrate (undercoat film UF, laminated film FS, mask MK) may be formed by CVD, ALD, PVD, spin coating, or the like. Mask MK may be formed by lithography. Opening OP in mask MK may be formed by etching mask MK. Each film may be flat or uneven. In one embodiment, substrate W may further have another film below under undercoat film UF. In this case, recesses in a shape corresponding to opening OP may be formed in laminated film FS and undercoat film UF and used as a mask for etching the other film.

In one embodiment, at least a part of the process for forming each film on the substrate W may be performed in the plasma processing space 10s as part of process ST1. For example, when the opening OP in the mask MK is formed by etching, the etching in process ST1 and the etching of the stacked film FS in process ST2 may be performed consecutively in the plasma processing space 10s. In one embodiment, after all or a part of each film on the substrate W is formed in an apparatus or chamber external to the plasma processing apparatus 1, the substrate W may be provided in the plasma processing space 10s.

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 simultaneous. The temperature of the substrate support 11 may be controlled to a given temperature before step ST1. That is, the substrate W may be provided to the substrate support 11 after the temperature of the substrate support 11 is controlled to a given temperature. In one embodiment, the given temperature is 0°C or less, -10°C or less, -20°C or less, or -30°C or less. In one embodiment, the given temperature is greater than or equal to -70°C, greater than or equal to -60°C, greater than or equal to -50°C, or greater than or equal to -40°C.

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.

(Step ST2: Etching of stacked film FS)
In step ST2, the laminated film FS of the substrate W is etched, whereby a portion of the laminated film FS that is not covered by the mask MK (a portion exposed at the opening OP) is etched to form a recess.

(Supply of First Processing Gas)
First, a first processing gas is supplied from the gas supply unit 20 into the plasma processing space 10s. The first processing gas includes hydrogen fluoride (HF) gas. In one embodiment, the HF gas may have the largest flow rate (partial pressure) of the first processing gas except for the inert gas. In one example, the flow rate of the 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 with respect to the total flow rate of the first processing gas (if the first processing gas includes an inert gas, the flow rate of all gases except the inert gas). The flow rate of the HF gas may be less than 100 vol.%, 99.5 vol.% or less, 98 vol.% or less, or 96 vol.% or less with respect to the total flow rate of the first processing gas. In one example, the flow rate of the HF gas is 70 vol.% or more and 96 vol.% or less with respect to the total flow rate of the first processing gas.

In one embodiment, the first process gas may include a phosphorus-containing gas. The phosphorus-containing gas is a gas containing phosphorus-containing molecules. The phosphorus-containing molecules may be oxides such as tetraphosphorus decaoxide (P ₄ O ₁₀ ), tetraphosphorus octoxide (P ₄ O ₈ ), and tetraphosphorus hexaoxide (P ₄ O ₆ ). Tetraphosphorus decaoxide is sometimes called diphosphorus pentoxide (P ₂ O ₅ ). The phosphorus-containing molecules may be halides (phosphorus halides) such as phosphorus trifluoride (PF ₃ ), phosphorus pentafluoride (PF ₅ ), phosphorus trichloride (PCl ₃ ), phosphorus pentachloride (PCl ₅ ), phosphorus tribromide (PBr ₃ ), phosphorus pentabromide (PBr ₅ ), and phosphorus iodide (PI ₃ ). That is, the phosphorus-containing molecules may include fluorine as a halogen element, such as phosphorus fluoride. Alternatively, the phosphorus-containing molecules may include a halogen element other than fluorine as a halogen element. The phosphorus-containing molecule may be a phosphoryl halide such as phosphoryl fluoride ( _POF3 ), phosphoryl chloride ( _POCl3 ), or phosphoryl bromide ( _POBr3 ). The phosphorus-containing molecule may be phosphine ( _PH3 ), calcium phosphide ( _{Ca3P2 , etc.} ), phosphoric acid ( _H3PO4 ), sodium phosphate ( _Na3PO4 ), _{hexafluorophosphoric} acid ( _HPF6 ), or the like. The phosphorus-containing molecule may be a fluorophosphine ( _HgPFh ), where the sum _of g and _h is 3 or _5. Examples of the fluorophosphine include _HPF2 and _H2PF3 . The first process gas may contain one or more of the above phosphorus-containing molecules as at least one phosphorus-containing molecule. For example, the first process gas may contain at least one phosphorus-containing molecule selected from the group consisting of _PF3 , _PCl3 , _PF5 , _PCl5 , _POCl3 , _PH3 , _PBr3 , and _PBr5 . When each phosphorus-containing molecule contained in the first process gas is liquid or solid, each phosphorus-containing molecule may be vaporized by heating or the like and supplied into the plasma processing space 10s.

In one example, the phosphorus-containing _gas may be _PClaFb (where a is an integer greater than or equal to 1, b is an integer greater than or equal to 0, and a+b is an integer less than or equal to 5 ₎ gas or _PCcHdFe (where d and e are integers greater than or equal to 1 and less than or equal to 5, and c is an integer greater than or equal to 0 and less than or equal to 9) _gas .

The PCl _a F _b gas may be, for example, at least one gas selected from the group consisting of PClF ₂ gas, PCl ₂ F gas, and PCl ₂ F ₃ gas.

The _PCcHdFe gas may be, for example, _{at least one gas selected from the group consisting of PF2CH3 gas, PF(CH3)2 gas, PH2CF3 gas , PH ( CF3 ) 2 gas , PCH3} ( _CF3 ) ₂ gas, _PH2F gas, and _PF3 ( _CH3 ) ₂ gas.

In one example, the phosphorus-containing gas may be _{PClcFdCeHf gas} (where c, d, e, and f are each an integer of 1 or more). The phosphorus-containing gas may _also be a gas _containing P (phosphorus), F (fluorine), and a halogen other than F (fluorine) (e.g., Cl, Br, or I) in its molecular structure, a gas containing P (phosphorus), F (fluorine), C (carbon), and H (hydrogen) in its molecular structure, or a gas containing P (phosphorus), F (fluorine), and H (hydrogen) in its molecular structure.

In one example, the phosphorus-containing gas may be a phosphine-based gas, which may include phosphine ( _PH3 ), a compound in which at least one hydrogen atom of phosphine is replaced with an appropriate substituent, and a phosphinic acid derivative.

The substituents substituting the hydrogen atoms of the phosphine are not particularly limited, and examples thereof include halogen atoms such as fluorine atoms and chlorine atoms; alkyl groups such as methyl groups, ethyl groups, and propyl groups; and hydroxyalkyl groups such as hydroxymethyl groups, hydroxyethyl groups, and hydroxypropyl groups. Examples include chlorine atoms, methyl groups, and hydroxymethyl groups.

Phosphinic acid derivatives include phosphinic acid (H ₃ O ₂ P), alkylphosphinic acids (PHO(OH)R), and dialkylphosphinic acids (PO(OH)R ₂ ).

Examples of the phosphine gas include _PCH3Cl2 ( _dichloro (methyl)phosphine) gas, P( _CH3 ) _2Cl (chloro(dimethyl)phosphine) gas, P( _HOCH2 ) _Cl2 (dichloro(hydroxylmethyl)phosphine) gas, P( _HOCH2 ) _2Cl (chloro(dihydroxylmethyl)phosphine) gas, P( _HOCH2 )( _CH3 ) ₂ (dimethyl(hydroxylmethyl)phosphine) gas, P( _HOCH2 ) ₂ ( _CH3 )(methyl(dihydroxylmethyl)phosphine) gas, P( _HOCH2 ) ₃ (tris(hydroxylmethyl)phosphine) gas, _H3O2P (phosphinic acid) gas, PHO(OH)( _CH3 ) (methylphosphinic acid) gas, and _PO (OH)( _CH3 ) ₂ At least one gas selected from the group consisting of (dimethylphosphinic acid) gas may be used.

In one embodiment, the flow rate of the phosphorus-containing gas contained in the first process gas is 20 vol. % or less, 10 vol. % or less, or 5 vol. % or less of the total flow rate of the first process gas.

In one embodiment, the first process gas may include a tungsten-containing gas. The tungsten-containing gas may be a gas containing tungsten and a halogen, and may be, for example, a WF _x Cl _y gas (x and y are integers from 0 to 6, and the sum of x and y is from 2 to 6). Specifically, the tungsten-containing gas may be a gas containing tungsten and fluorine, such as tungsten difluoride (WF ₂ ) gas, tungsten tetrafluoride (WF ₄ ) gas, tungsten pentafluoride (WF ₅ ) gas, or tungsten hexafluoride (WF ₆ ) gas, or a gas containing tungsten and chlorine, such as tungsten dichloride (WCl ₂ ) gas, tungsten tetrachloride (WCl ₄ ) gas, tungsten pentachloride (WCl ₅ ) gas, or tungsten hexachloride (WCl ₆ ) gas. Among these, the gas may be at least one of WF ₆ gas and WCl ₆ gas. The flow rate of the tungsten-containing gas may be 5% by volume or less of the total flow rate of the first process gas. In one embodiment, the first process gas may include at least one of a titanium-containing gas, a molybdenum-containing gas, and a ruthenium-containing gas instead of or in addition to the tungsten-containing gas.

In one embodiment, the first process gas may include a carbon-containing gas. The carbon-containing gas may be, for example, one or both of a fluorocarbon gas and a hydrofluorocarbon gas. In one 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, _{C2H2F4 gas} , _C2H3F3 gas _{, C2H4F2 gas , C3HF7 gas , C3H2F2} gas, _C3H2F4 gas _{, C3H2F6} gas _{, C3H3F5 gas , C4H2F6 gas , C4H5F5 gas , C4H2F8 gas , C5H2F6} gas, _C5H2F10 gas _{, and C5H3F7 gas .} The carbon-containing gas may be linear and have an unsaturated bond. The linear carbon-containing gas having an unsaturated bond may be, for example, at least one selected from the group consisting of C ₃ F ₆ (hexafluoropropene) gas, C ₄ F ₈ (octafluoro-1-butene, octafluoro-2-butene) gas, C ₃ H ₂ F ₄ (1,3,3,3-tetrafluoropropene) gas, C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas, C ₄ F ₈ O (pentafluoroethyl trifluorovinyl ether) gas, CF ₃ COF gas (1,2,2,2-tetrafluoroethane-1-one), CHF ₂ COF (difluoroacetic acid fluoride) gas, and COF ₂ (carbonyl fluoride) gas. The carbon-containing gas may contain a halogen other than fluorine, may contain fluorine and a halogen other than fluorine, or may contain two or more halogens other than fluorine. In one example, the carbon-containing gas _may be _{CsHtBr uClvFw} (where s is an integer of ₁ or more, _{and t, u, v, and w are each an integer of 0 or more), or may be CsHtBr uClvFw ( where s is an} integer of 1 or more and 7 or less, and t, u, v, and w are each an integer of 0 or more and 16 or less, satisfying 4≦t+u+v+w≦16). For example, the carbon-containing gas may include at _least one _selected from the group consisting of _CCl4 , _CH2Cl2 , _CHCl3 , _{CF2Cl2 , CH2ClF} , _{CHCl2F , CBr2F2} , _C2F5Br , _CF3I , _{C2F5I ,} and _{C3F7I .}

In one embodiment, the first process gas may include an oxygen-containing gas. The oxygen-containing gas may be, for example, at least one gas selected from the group consisting of O ₂ , CO, CO ₂ , H ₂ O, and H ₂ O _2. In one example, the oxygen-containing gas may be an oxygen-containing gas other than H ₂ O, for example, at least one gas selected from the group consisting of O ₂ , CO, CO _2, and H ₂ O _2. The flow rate of the oxygen-containing gas may be adjusted according to the flow rate of other gases (e.g., carbon-containing gas) contained in the first process gas.

In one embodiment, the first process gas may include a halogen-containing gas other than fluorine. The halogen-containing gas other than fluorine may be a chlorine-containing _gas , _a bromine-containing gas, and/or an iodine-containing _gas . The chlorine-containing gas may be at least one gas selected from the group consisting of _Cl2 , _HCl , _SiCl2 , SiCl4, _CCl4 , _SiH2Cl2 , _Si2Cl6 , _CHCl3 , _SO2Cl2 , _BCl3 , _PCl3 , _PCl5 , _{and POCl3} . The bromine-containing gas may be 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 may be 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 gas 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.

In one embodiment, the first process gas may further include an inert gas. In one example, the inert gas may be a noble gas such as Ar gas, He gas, or Kr gas, or nitrogen gas.

In one embodiment, the first process gas may contain a gas capable of generating hydrogen fluoride species (HF species) in plasma in place of some or all of the HF gas. The HF species includes at least one of hydrogen fluoride gas, radicals, and ions.

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. In one example, the hydrofluorocarbon gas is at least _one selected from the group consisting of CH ₂ F ₂ gas, C ₃ H ₂ F ₄ gas, C _{3 H 2 F 6} gas, C ₃ H ₃ F ₅ gas, C ₄ H ₂ F ₆ gas, C ₄ H ₅ F ₅ gas, C ₄ H ₂ F ₈ gas, C ₅ H ₂ F 6 gas, C 5 H ₂ F ₁₀ gas, and C ₅ H ₃ F ₇ gas. In one example, the hydrofluorocarbon gas is at least one selected from the group consisting of CH ₂ F ₂ gas, C ₃ H ₂ F ₄ gas, C ₃ H ₂ F ₆ gas, and C ₄ H ₂ F ₆ gas.

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. In one 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.) _.

(Plasma Generation)
Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and/or the upper electrode of the shower head 13. As a result, a high-frequency electric field is generated between the shower head 13 and the substrate support 11, and plasma is generated from the first processing gas in the plasma processing space 10s. A bias signal may be supplied to the lower electrode of the substrate support 11. In this case, a bias potential is generated between the plasma and the substrate W. The bias potential attracts active species such as ions and radicals in the plasma to the substrate W. The bias signal may be a bias RF signal supplied from the second RF generator 31b. The bias signal may also be a bias DC signal supplied from the DC generator 32a.

In one embodiment, the source RF signal and the 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 bias signal are pulse waves, the periods of the two pulse waves may or may not be synchronized. The duty ratio of the source RF signal and/or the bias signal pulse wave may be set appropriately, for example, 1 to 80%, or 5 to 50%. When a bias DC signal is used as the bias signal, the pulse wave may have a rectangular, trapezoidal, triangular, or combination thereof. The polarity of the bias DC signal may be negative or positive, as long as the potential of the substrate W is set to provide a potential difference between the plasma and the substrate to attract ions.

In one embodiment, the supply and halt of at least one of the source RF signal and the bias signal may be alternately repeated. For example, the supply and halt of the bias signal may be alternately repeated while the source RF signal is continuously supplied. For example, the bias signal may be continuously supplied while the supply and halt of the source RF signal are alternately repeated. For example, the supply and halt of both the source RF signal and the bias signal may be alternately repeated.

In one embodiment, the composition of the first process gas and the flow rate (partial pressure) of each gas may be constant during processing in step ST2. In one embodiment, the composition of the first process gas and/or the flow rate (partial pressure) of each gas may be changed as etching progresses in step ST2.

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

In one embodiment, the pressure in the plasma processing chamber 10 during processing in step ST2 may be controlled to 1 mTorr or more and 50 mTorr or less.

Figure 5 is a diagram showing an example of the cross-sectional structure of the substrate W after processing in step ST2. By etching in step ST2, the portion of the laminated film FS that is not covered by the mask MK (the portion exposed at the opening OP) is etched to form a recess RC. Here, the opening dimensions of the recess RC formed in the laminated film FS may be non-uniform along the depth direction. For example, the opening dimensions of the recess RC may differ depending on the type of film that constitutes the laminated film FS. The reason for this is not necessarily clear, but it is thought that, for example, the horizontal etching rate differs for each film due to differences in reactivity to active species in the plasma and the type and amount of by-products deposited on the side walls.

In the example shown in FIG. 5, the opening dimensions of the recess RC formed in the stacked film FS are different between the silicon oxide film SF1 and the silicon nitride film SF2. In one embodiment, the opening dimension CD1 in the silicon oxide film SF1 is smaller than the opening dimension CD2 in the silicon nitride film SF2. The recess RC has opening dimensions CD1 and CD2 alternating along the depth direction. As a result, the sidewall SS of the stacked film FS that defines the recess RC has irregularities along the depth direction. In one example, the sidewall SS of the stacked film FS may have a shell-shaped irregular shape along the depth direction. Such irregularities are sometimes called scallops due to their shape. Scallops are one type of shape abnormality caused by etching. In one embodiment, the surface roughness of the sidewall SS (the difference between the opening dimension CD1 and the opening dimension CD2) is 0.2 nm or more.

In this method, the surface roughness of the sidewall SS of the laminated film FS (uniformity of the opening dimensions of the recess RC in the depth direction) can be improved by step ST3 described below.

(Step ST3: Supply of hydrogen fluoride to recess)
In step ST3, hydrogen fluoride is supplied to the recess RC of the laminated film FS. In one embodiment, hydrogen fluoride may be supplied as HF gas. In one embodiment, step ST3 may be performed consecutively from step ST2 in the same chamber as step ST2. Specifically, a second process gas containing HF gas is supplied from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the second process gas may contain the above-mentioned inert gas. By supplying hydrogen fluoride gas to the recess RC formed in the laminated film FS of the substrate W, the sidewall SS of the laminated film FS is etched in the horizontal direction. The etching rate for HF gas may differ for each film constituting the sidewall SS. That is, the etching amount of the sidewall SS etched in step ST3 may differ for each film.

In one embodiment, the HF gas may have the largest flow rate (partial pressure) of the second process gas excluding the inert gas. In one example, the flow rate of the 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 with respect to the total flow rate of the second process gas (if the second process gas includes an inert gas, the flow rate of all gases excluding the inert gas). The flow rate of the HF gas may be less than 100 vol.%, 99.5 vol.% or less, 98 vol.% or less, or 96 vol.% or less with respect to the total flow rate of the second process gas. In one example, the flow rate of the HF gas is 70 vol.% or more and 96 vol.% or less with respect to the total flow rate of the second process gas.

In one embodiment, the second process gas may contain the phosphorus-containing gas described above. In one embodiment, the flow rate of the phosphorus-containing gas contained in the second process gas is 20 vol. % or less, 10 vol. % or less, or 5 vol. % or less of the total flow rate of the second process gas.

In one embodiment, during the processing in step ST3, the temperature of the substrate support part 11 may be controlled to a temperature lower than the given temperature set in step ST1 and/or step ST2, or may be controlled to a temperature higher than the given temperature. In one example, the temperature of the substrate support part 11 is 0°C or lower, -10°C or lower, -20°C or -30°C, -40°C or -50°C or lower. In one embodiment, the given temperature is -70°C or higher or -60°C or higher. In one embodiment, instead of the temperature of the substrate support part 11, the temperature of the substrate W may be controlled to the above-mentioned temperature lower than the given temperature. This may improve the etching rate of the silicon oxide film by HF gas.

In one embodiment, the pressure in the plasma processing chamber 10 during processing in step ST3 is higher than the pressure in the plasma processing chamber 10 during step ST2.

Figure 6 is a diagram showing an example of the cross-sectional structure of the substrate W after processing in step ST3. As shown in Figure 6, step ST3 can make the opening dimension CD10 of the silicon oxide film SF1 of the recess RC substantially the same as the opening dimension CD20 of the silicon nitride film SF2. In one embodiment, the surface roughness of the sidewall SS (the difference between the opening dimension CD10 and the opening dimension CD20) is less than 1 nm. In other words, the surface roughness of the sidewall SS can be improved.

The reason for this is believed to be that, among the side walls SS of the stacked film FS, the horizontal etching of the silicon oxide film SF1 progresses, while the etching of the silicon nitride film SF2 is suppressed. In one example, the etching selectivity of the silicon oxide film SF1 relative to the silicon nitride film SF2 (etching rate of the silicon oxide film SF1 by the second processing gas/etching rate of the silicon nitride film SF2 by the second processing gas) is 10 or more, 15 or more, 20 or more, or 25 or more.

This method can prevent shape abnormalities, such as callops, in the recesses formed in the laminated film by etching, and improve the surface roughness of the sidewalls of the laminated film.

<Modification>
Modifications of the present method will be described below, but the present disclosure is not limited to the following modifications.

In one embodiment, step ST3 may include the following two steps, step ST31 and step ST32. Step ST31 is a step of controlling the temperature of the substrate support part 11 to a first temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a first pressure. Step ST32 is performed after step ST31 and is a step of controlling the temperature of the substrate support part 11 to a second temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a second pressure. In one embodiment, in steps ST31 and ST32, instead of controlling the temperature of the substrate support part 11, the temperature of the substrate W may be controlled.

In one embodiment, the second temperature may be greater than the first temperature. In one embodiment, the second pressure may be less than the first pressure.

Figure 7 is a graph showing an example of an adsorption equilibrium pressure curve for hydrogen fluoride. The horizontal axis is temperature (°C). The vertical axis is pressure (mTorr). C1 is the adsorption equilibrium pressure curve for hydrogen fluoride. C2 is the saturated vapor pressure curve for hydrogen fluoride. At the temperature and pressure on the adsorption equilibrium pressure curve C1 in the graph of Figure 7, the adsorption and desorption of hydrogen fluoride are in equilibrium. In one embodiment, the adsorption equilibrium pressure curve C1 may be drawn by an exponential function approximated using measurement data based on the BET adsorption theory.

In one embodiment, the first temperature and the first pressure are located in a first region above the hydrogen fluoride adsorption equilibrium pressure curve C1 in the graph shown in FIG. 7. As a result, in step ST31, hydrogen fluoride is adsorbed on the surface of the sidewall SS of the laminated film FS, and volatile by-products are formed. The first region may be located in a region below the saturated vapor pressure curve C2 of hydrogen fluoride (the region indicated by "R1" in the graph in FIG. 7). In this case, hydrogen fluoride is adsorbed in the gas phase on the surface of the sidewall SS of the laminated film FS. The first region may be located above the saturated vapor pressure curve C2. In this case, hydrogen fluoride is adsorbed in the liquid phase on the surface of the sidewall SS of the laminated film FS. In one embodiment, the amount of hydrogen fluoride adsorbed and the amount of by-products formed on the sidewall SS of the silicon oxide film SF1 are greater than those on the sidewall SS of the silicon nitride film SF2.

In one embodiment, the second temperature and the second pressure are located in a second region (the region indicated by "R2" in the graph of FIG. 7) below the hydrogen fluoride adsorption equilibrium pressure curve C1 in the graph shown in FIG. 7. As a result, in step ST32, the hydrogen fluoride and by-products adsorbed on the surface of the sidewall SS of the stacked film FS are desorbed. In one embodiment, the amount of hydrogen fluoride and by-products desorbed on the sidewall SS of the silicon oxide film SF1 is greater than that on the sidewall SS of the silicon nitride film SF2. As a result, the horizontal etching of the silicon oxide film SF1 proceeds more rapidly than that of the silicon nitride film SF2.

In one embodiment, in step ST3, a cycle including steps ST31 and ST32 may be performed multiple times.

In one embodiment, process ST3 may be performed in a chamber (hereinafter referred to as the "second chamber") different from process ST2. For example, process ST3 may include a step of transporting the substrate W from the plasma processing chamber 10 to the second chamber, and a step of supplying the above-mentioned second processing gas to the substrate W in the second chamber. In one embodiment, the second chamber may be part of a substrate processing system PS1 described below. In one embodiment, the second chamber may be part of another substrate processing apparatus that is external to the plasma processing system including the plasma processing apparatus 1.

In one embodiment, the conditions for step ST3 may be set based on data indicating the shape of the recess RC in the laminated film FS. The surface roughness of the sidewall SS after step ST2 may vary depending on the depth of the recess RC. In such a case, by setting the conditions for step ST3 based on data indicating the shape of the recess RC in the laminated film FS, the surface roughness of the sidewall SS can be improved regardless of the depth of the recess RC.

The data indicating the shape of the recess RC of the laminated film FS may be obtained by observing the substrate W after step ST2 using a sensor. The sensor may be an optical sensor or another type of sensor. The sensor may be configured to be capable of observing the substrate W placed on the substrate support 11 in the plasma processing chamber 10, or may be configured to be capable of observing the substrate W outside the plasma processing chamber 10. In one example, the sensor is installed in a transfer module TM described later. The data indicating the shape of the recess RC of the laminated film FS may be data estimated from the plasma emission state in step ST2 and/or the mass change of the substrate W before and after step ST2, or may be data estimated by simulation or the like.

In one embodiment, the conditions set based on data indicating the shape of the recess RC of the laminated film FS may include at least one selected from the group consisting of the pressure of the plasma processing chamber 10 in which the substrate W is housed (hereinafter also referred to as "pressure"), the temperature of the substrate W or the substrate support part 11 supporting the substrate W (hereinafter also referred to as "temperature"), and the flow rate of the hydrogen fluoride gas (hereinafter also referred to as "flow rate").

In one embodiment, the pressure, temperature, and flow rate may be set as follows based on data indicating the shape of the recess RC. Here, the pressure, temperature, and flow rate when the surface roughness of the sidewall SS is uniform or approximately uniform in the depth direction of the recess RC are set as the reference values. When the surface roughness of the sidewall SS decreases from the upper side (opening side) to the lower side (bottom side) of the recess RC, the pressure and flow rate may be set lower than the reference value, and the temperature may be set higher than the reference value. When the surface roughness of the sidewall SS increases from the upper side to the lower side of the recess RC, the pressure and flow rate may be set higher than the reference value, and the temperature may be set lower than the reference value. When the surface roughness of the middle part of the recess RC is the smallest and the surface roughness of the upper and lower sides of the recess RC is approximately the same, the pressure and flow rate may remain at the reference value, and only the temperature may be set lower. When the surface roughness of the middle part of the recess RC is the smallest and the surface roughness of the lower side of the recess RC is greater than that of the upper side, the temperature may remain at the reference value, and the pressure and flow rate may be set higher than the reference value. Furthermore, if the surface roughness of the middle part of the recess RC is the smallest and the surface roughness of the upper part of the recess RC is greater than that of the lower part, the pressure and flow rate may be set lower than the reference values while the temperature remains at the reference value.

In one embodiment, during the execution of step ST3, the conditions of step ST3 may be changed depending on the depth of the recess RC. For example, step 3 may include the following two steps ST33 and ST34. Step 33 is a step of supplying hydrogen fluoride to the recess RC of the laminated film FS under first conditions. Step 34 is a step of supplying the hydrogen fluoride to the recess RC of the laminated film FS under second conditions different from the first conditions. In step 3, a cycle including steps 33 and 34 may be executed multiple times.

In one embodiment, the second condition may differ from the first condition in at least one selected from the group consisting of the pressure of the plasma processing chamber 10 in which the substrate W is housed, the temperature of the substrate W or the substrate support 11 that supports the substrate W, and the flow rate of the hydrogen fluoride gas.

In one embodiment, the method may be performed using a substrate processing system PS1 that includes multiple substrate processing chambers.

Figure 8 is a diagram for explaining an example configuration of the substrate processing system PS1. The substrate processing system PS1 has substrate processing chambers PM1 to PM6 (hereinafter collectively referred to as "substrate processing modules PM"), a transfer module TM, load lock modules LLM1 and LLM2 (hereinafter collectively referred to as "load lock modules LLM"), a loader module LM, and load ports LP1 to LP3 (hereinafter collectively referred to as "load ports LP"). The controller CT controls each component of the substrate processing system PS1 to perform a given process on the substrate W.

The substrate processing module PM performs processes such as etching, trimming, film formation, annealing, doping, lithography, cleaning, and ashing on the substrate W. At least one of the substrate processing chambers PM1 to PM6 may be the plasma processing apparatus 1 shown in FIG. 1 or FIG. 2.

The transfer module TM has a transfer device that transfers the substrate W, and transfers the substrate W between the substrate processing modules PM or between the substrate processing module PM and the load lock module LLM. The substrate processing module PM and the load lock module LLM are arranged adjacent to the transfer module TM. The transfer module TM, the substrate processing module PM, and the load lock module LLM are spatially isolated or connected by openable and closable gate valves.

The load lock modules LLM1 and LLM2 are provided between the transfer module TM and the loader module LM. The load lock module LLM can switch its internal pressure between atmospheric pressure and vacuum. "Atmospheric pressure" can be the pressure outside each module included in the substrate processing system PS1. "Vacuum" can be a pressure lower than atmospheric pressure, for example a medium vacuum of 0.1 Pa to 100 Pa. The load lock module LLM transfers the substrate W from the loader module LM, which is at atmospheric pressure, to the transfer module TM, which is at vacuum, and also transfers the substrate W from the transfer module TM, which is at vacuum, to the loader module LM, which is at atmospheric pressure.

The loader module LM has a transport device that transports substrates W, and transports substrates W between the load lock module LLM and the load board LP. Inside the load port LP, for example, a FOUP (Front Opening Unified Pod) capable of storing 25 substrates W or an empty FOUP can be placed. The loader module LM removes substrates W from the FOUP in the load port LP and transports them to the load lock module LLM. The loader module LM also removes substrates W from the load lock module LLM and transports them to the FOUP in the load board LP.

The controller CT controls each component of the substrate processing system PS1 to perform a given process on the substrate W. The controller CT stores a recipe in which the process procedure, process conditions, transport conditions, etc. are set, and controls each component of the substrate processing system PS1 to perform a given process on the substrate W according to the recipe. The controller CT may have some or all of the functions of the controller 2 shown in Figures 1 and 2. The method can be performed in the substrate processing system PS1 under the control of the controller CT. In one embodiment, steps ST1 to ST3 may be performed in one of the substrate processing chambers PM1 to PM6. Also, for example, steps ST1 and ST2 may be performed in one of the substrate processing chambers PM1 to PM6, and step ST3 may be performed in the other one of the substrate processing chambers PM1 to PM6.

In one embodiment, in step ST3, a processing liquid containing hydrogen fluoride may be supplied to the substrate. For example, step ST3 may include a step of transporting the substrate W to a liquid processing apparatus outside the plasma processing chamber 10, and a step of supplying a processing liquid containing hydrogen fluoride to the substrate W in the liquid processing apparatus. The processing liquid may be, for example, hydrofluoric acid (DHF) or buffered hydrofluoric acid (BHF). In one embodiment, the liquid processing apparatus may be part of a substrate processing system PS2 shown below.

In one embodiment, the method may be performed using a substrate processing system PS2 that includes a liquid processing device.

Figure 9 is a diagram for explaining an example configuration of the substrate processing system PS2. In one embodiment, the substrate processing system PS2 includes a plasma processing apparatus 1 (see Figures 1 and 2), a liquid processing apparatus 100, and a controller CT2. The substrate processing system PS2 may include a transport device that transports the substrate W between the plasma processing apparatus 1 and the liquid processing apparatus 100.

In one embodiment, the liquid processing apparatus 100 includes a container 110 for containing a processing liquid including hydrogen fluoride, a container 112 for containing a rinsing liquid, and a container 114 for containing pure water. In one embodiment, the liquid processing apparatus 100 may include a dryer for drying the substrate W.

In one embodiment, the liquid processing apparatus 100 includes an entrance 116 for receiving the substrate W unloaded from the plasma processing apparatus 1, and an exit 118 for unloading the substrate W to the plasma processing apparatus 1. In one embodiment, the liquid processing apparatus 100 includes a transport device 120 for transporting the substrate W. The transport device 120 transports the substrate W from the entrance 116 to the container 110. The transport device 120 transports the substrate W from the container 110 to the container 112. The transport device 120 transports the substrate W from the container 112 to the container 114. The transport device 120 transports the substrate W from the container 114 to the exit 118.

The control unit CT2 is configured to control each part of the plasma processing apparatus 1 and the liquid processing apparatus 100. The control unit CT2 may have some or all of the functions of the control unit 2 shown in Figures 1 and 2. The method can be executed in the substrate processing system PS2 by controlling the control unit CT2.

In one embodiment, process ST and process ST2 are performed in the plasma processing apparatus 1 of the substrate processing system PS2. Next, in process ST3, the substrate W is transported from the plasma processing apparatus 1 to the entrance 116 of the liquid processing apparatus 100. The substrate W is then transported to the container 110, where it is immersed in a processing liquid containing hydrogen fluoride. The hydrogen fluoride is supplied to the recess RC formed in the laminate film FS of the substrate W. This causes the sidewall SS of the laminate film FS to be etched horizontally. The temperature of the processing liquid may be maintained at 15°C to 25°C during etching.

In one embodiment, the substrate W may be transferred from the container 110 to the container 112 and immersed in the rinse liquid. The substrate W may further be transferred from the container 112 to the container 114 and immersed in pure water. In one embodiment, the substrate W may be dried in a dryer of the liquid processing apparatus 100. In one embodiment, the substrate W may be transferred to the plasma processing apparatus 1 and dried by reducing the pressure in the plasma processing chamber 10.

Embodiments of the present disclosure further include the following aspects:

(Appendix 1)
1. An etching method comprising the steps of:
(a) providing a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack;
(b) etching the laminated film using plasma generated from a first process gas to form a recess in the laminated film;
(c) supplying hydrogen fluoride to the recess of the laminated film;
An etching method comprising:

(Appendix 2)
2. The etching method according to claim 1, wherein the laminated film includes at least two selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film.

(Appendix 3)
3. The etching method according to claim 1, wherein the laminated film is formed by alternately laminating a plurality of silicon oxide films and silicon nitride films.

(Appendix 4)
4. The etching method of claim 1, wherein the mask is a carbon-containing film or a metal-containing film.

(Appendix 5)
5. The etching method according to claim 1, wherein the first process gas contains hydrogen fluoride gas.

(Appendix 6)
6. The etching method according to claim 1, wherein the first process gas contains at least one gas selected from the group consisting of a hydrogen fluoride gas, a hydrofluorocarbon gas, and a mixed gas of a hydrogen-containing gas and a fluorine-containing gas.

(Appendix 7)
7. The etching method of claim 1, wherein the first process gas further comprises a phosphorus-containing gas.

(Appendix 8)
8. The etching method of claim 1, wherein the first process gas further contains at least one gas selected from the group consisting of a carbon-containing gas, an oxygen-containing gas, and a metal-containing gas.

(Appendix 9)
9. The etching method of claim 1, wherein at the completion of step (b), the recess has a first opening dimension and a second opening dimension different from the first opening dimension alternately along a depth direction of the recess.

(Appendix 10)
10. The etching method of claim 9, wherein a difference between the first opening dimension and the second opening dimension is 0.2 nm or more.

(Appendix 11)
(a) includes placing the substrate in a first chamber;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
11. The etching method of claim 1, wherein (c) includes supplying a second process gas containing hydrogen fluoride gas into the first chamber.

(Appendix 12)
The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
12. The etching method of claim 11, wherein the second temperature is greater than the first temperature and/or the second pressure is less than the first pressure.

(Appendix 13)
The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
12. The etching method according to claim 11, wherein, in a graph showing an adsorption equilibrium pressure curve of hydrogen fluoride, with the horizontal axis representing temperature and the vertical axis representing pressure, the first temperature and the first pressure are located in a first region above the adsorption equilibrium pressure curve, and the second temperature and the second pressure are located in a second region below the adsorption equilibrium pressure curve.

(Appendix 14)
(a) includes placing the substrate in a first chamber;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
11. The etching method of any one of Appendix 1 to Appendix 10, wherein (c) includes transporting the substrate from the first chamber to a second chamber different from the first chamber, and supplying a second process gas containing hydrogen fluoride gas into the second chamber.

(Appendix 15)
The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
15. The etching method of claim 14, wherein the second temperature is greater than the first temperature and/or the second pressure is less than the first pressure.

(Appendix 16)
The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
15. The etching method according to claim 14, wherein, in a graph showing an adsorption equilibrium pressure curve of hydrogen fluoride, with the horizontal axis representing temperature and the vertical axis representing pressure, the first temperature and the first pressure are located in a first region above the adsorption equilibrium pressure curve, and the second temperature and the second pressure are located in a second region below the adsorption equilibrium pressure curve.

(Appendix 17)
17. The etching method according to any one of claims 11 to 16, wherein a temperature of the substrate or a substrate support part supporting the substrate in (c) is controlled to a temperature lower than a temperature of the substrate or a substrate support part supporting the substrate in (b).

(Appendix 18)
18. The etching method of claim 11, wherein the second process gas further comprises a phosphorus-containing gas.

(Appendix 19)
(a) includes placing the substrate in a first chamber;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
11. The etching method according to claim 1, wherein (c) includes transporting the substrate to an outside of the first chamber, and supplying a treatment liquid containing hydrogen fluoride to the substrate outside the first chamber.

(Appendix 20)
20. The etching method according to claim 19, wherein the treatment liquid comprises hydrofluoric acid (DHF) or buffered hydrofluoric acid (BHF).

(Appendix 21)
(a) includes disposing the substrate in a first chamber of a plasma processing system;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
11. The etching method according to claim 1, wherein (c) includes transporting the substrate to a substrate processing apparatus outside the plasma processing system, and supplying hydrogen fluoride to the recess of the laminate film in the substrate processing apparatus.

(Appendix 22)
19. The etching method according to any one of claims 1 to 18, further comprising the step of setting the condition of (c) based on data indicating a shape of the recess in the laminated film.

(Appendix 23)
23. The etching method according to claim 22, wherein the conditions include at least one selected from the group consisting of a pressure of a chamber in which the substrate is accommodated, a temperature of the substrate or a substrate support part that supports the substrate, and a flow rate of the hydrogen fluoride gas.

(Appendix 24)
The (c) is
(c3) supplying the hydrogen fluoride to the recess of the laminated film under first conditions;
(c4) supplying the hydrogen fluoride to the recess of the laminated film under second conditions different from the first conditions;
19. The etching method of any one of claims 1 to 18, comprising:

(Appendix 25)
25. The etching method according to claim 24, wherein the second condition is different from the first condition in at least one selected from the group consisting of a pressure of a chamber in which the substrate is accommodated, a temperature of the substrate or a substrate support part that supports the substrate, and a flow rate of the hydrogen fluoride gas.

(Appendix 26)
A plasma processing apparatus having a chamber, a plasma generating unit, a gas supply unit, and a control unit, the control unit comprising:
(a) controlling a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack to the chamber;
(b) controlling, in the chamber, to etch the laminated film using plasma generated from a first process gas by the plasma generating unit to form a recess in the laminated film;
(c) controlling the gas supply unit to supply a second process gas containing hydrogen fluoride gas to the recess of the laminated film in the chamber;
A plasma processing apparatus that performs the above steps.

(Appendix 27)
A substrate processing system having a first chamber, a plasma generating unit, a second chamber, a gas supply unit, and a control unit, the control unit comprising:
(a) controlling a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack to the first chamber;
(b) controlling, in the first chamber, to etch the laminated film using plasma generated from a first process gas by the plasma generating unit to form a recess in the laminated film;
(c) transferring the substrate from the first chamber to the second chamber, and controlling, in the second chamber, to supply a second process gas including hydrogen fluoride gas to the recess of the laminated film by the gas supply unit;
A substrate processing system that performs the above steps.

(Appendix 28)
A substrate processing system including a plasma processing apparatus having a chamber, a plasma generating unit, and a gas supply unit, a liquid processing apparatus, and a control unit, the control unit comprising:
(a) controlling a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack to a chamber of the plasma processing apparatus;
(b) controlling, in the chamber, to etch the laminated film using plasma generated from a first process gas by the plasma generating unit to form a recess in the laminated film;
(c) transporting the substrate from the chamber to the liquid treatment device, and controlling the supply of a treatment liquid containing hydrogen fluoride to the recess of the laminated film in the liquid treatment device;
A substrate processing system that performs the above steps.

(Appendix 29)
1. A device manufacturing method comprising the steps of:
(a) providing a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack;
(b) etching the laminated film using plasma generated from a first process gas to form a recess in the laminated film;
(c) supplying hydrogen fluoride to the recess of the laminated film;
A device manufacturing method comprising:

(Appendix 30)
A computer of a substrate processing system including a control unit,
(a) providing a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack;
(b) etching the laminated film using plasma generated from a first process gas to form a recess in the laminated film;
(c) controlling the supply of hydrogen fluoride to the recess of the laminated film;
A program that executes the following.

(Appendix 31)
A storage medium storing the program according to claim 30.

The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications of the above embodiments may be made without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment may be added to another embodiment. Also, some components in one embodiment may be replaced with corresponding components in another embodiment.

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, FS: Stacked film, MK: Mask, OP: Opening, PS1, PS2: Substrate processing apparatus RC: Recess, SF1: Silicon oxide film, SF2: Silicon nitride film, SS: Side wall, UF: Base film, W: Substrate

Claims (27)

1. An etching method comprising the steps of:
(a) providing a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack;
(b) etching the laminated film using plasma generated from a first process gas to form a recess in the laminated film;
(c) supplying hydrogen fluoride to the recess of the laminated film;
An etching method comprising: The etching method according to claim 1, wherein the laminated film includes at least two selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film. The etching method according to claim 2, wherein the laminated film is composed of multiple alternating layers of silicon oxide films and silicon nitride films. The etching method according to any one of claims 1 to 3, wherein the mask is a carbon-containing film or a metal-containing film. The etching method according to claim 1, wherein the first process gas includes hydrogen fluoride gas. The etching method according to claim 1, wherein the first process gas includes at least one selected from the group consisting of hydrogen fluoride gas, hydrofluorocarbon gas, and a mixed gas of a hydrogen-containing gas and a fluorine-containing gas. The etching method according to claim 5 or 6, wherein the first process gas further contains a phosphorus-containing gas. The etching method according to claim 5 or 6, wherein the first process gas further contains at least one gas selected from the group consisting of a carbon-containing gas, an oxygen-containing gas, and a metal-containing gas. The etching method according to claim 1, wherein at the end of (b), the recess has a first opening dimension and a second opening dimension different from the first opening dimension, alternating along the depth direction of the recess. The etching method according to claim 9, wherein the difference between the first opening dimension and the second opening dimension is 0.2 nm or more. (a) includes placing the substrate in a first chamber;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
2. The etching method of claim 1, wherein (c) comprises supplying a second process gas comprising hydrogen fluoride gas into the first chamber. The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
12. The etching method of claim 11, wherein the second temperature is higher than the first temperature and/or the second pressure is lower than the first pressure. The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
12. The etching method according to claim 11, wherein, in a graph showing an adsorption equilibrium pressure curve of hydrogen fluoride, with the horizontal axis representing temperature and the vertical axis representing pressure, the first temperature and the first pressure are located in a first region above the adsorption equilibrium pressure curve, and the second temperature and the second pressure are located in a second region below the adsorption equilibrium pressure curve. (a) includes placing the substrate in a first chamber;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
2. The etching method of claim 1, wherein (c) comprises transferring the substrate from the first chamber to a second chamber different from the first chamber, and supplying a second process gas containing hydrogen fluoride gas into the second chamber. The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
15. The etching method of claim 14, wherein the second temperature is higher than the first temperature and/or the second pressure is lower than the first pressure. The (c) is
(c1) controlling a temperature of the substrate or a substrate support supporting the substrate to a first temperature and controlling a partial pressure of the hydrogen fluoride gas in the chamber to a first pressure;
(c2) after (c1), controlling the temperature of the substrate or the substrate support to a second temperature and controlling the partial pressure of the hydrogen fluoride gas in the chamber to a second pressure;
Including,
15. The etching method according to claim 14, wherein, in a graph showing an adsorption equilibrium pressure curve of hydrogen fluoride, with the horizontal axis representing temperature and the vertical axis representing pressure, the first temperature and the first pressure are located in a first region above the adsorption equilibrium pressure curve, and the second temperature and the second pressure are located in a second region below the adsorption equilibrium pressure curve. The etching method according to any one of claims 11 to 16, wherein the temperature of the substrate or the substrate support part supporting the substrate in (c) is controlled to a temperature lower than the temperature of the substrate or the substrate support part supporting the substrate in (b). The etching method according to any one of claims 11 to 16, wherein the second process gas further includes a phosphorus-containing gas. (a) includes placing the substrate in a first chamber;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
2. The etching method according to claim 1, wherein the step (c) includes: transferring the substrate to an outside of the first chamber; and supplying a processing liquid containing hydrogen fluoride to the substrate outside the first chamber. The etching method according to claim 19, wherein the processing solution contains hydrofluoric acid (DHF) or buffered hydrofluoric acid (BHF). (a) includes disposing the substrate in a first chamber of a plasma processing system;
(b) includes supplying the first process gas into the first chamber to generate the plasma;
2. The etching method according to claim 1, wherein (c) comprises: transporting the substrate to a substrate processing apparatus outside the plasma processing system; and supplying hydrogen fluoride to the recess of the laminated film in the substrate processing apparatus. The etching method according to claim 1, further comprising a step of setting the conditions of (c) based on data indicating the shape of the recess in the laminated film. The etching method according to claim 22, wherein the conditions include at least one selected from the group consisting of the pressure of a chamber in which the substrate is housed, the temperature of the substrate or a substrate support part that supports the substrate, and the flow rate of the hydrogen fluoride gas. The (c) is
(c3) supplying the hydrogen fluoride to the recess of the laminated film under first conditions;
(c4) supplying the hydrogen fluoride to the recess of the laminated film under second conditions different from the first conditions;
The etching method of claim 1 , comprising: The etching method according to claim 24, wherein the second condition is different from the first condition in at least one selected from the group consisting of the pressure of a chamber in which the substrate is housed, the temperature of the substrate or a substrate support part that supports the substrate, and the flow rate of the hydrogen fluoride gas. A plasma processing apparatus having a chamber, a plasma generating unit, a gas supply unit, and a control unit, the control unit comprising:
(a) controlling a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack to the chamber;
(b) controlling, in the chamber, to etch the laminated film using plasma generated from a first process gas by the plasma generating unit to form a recess in the laminated film;
(c) controlling the gas supply unit to supply a second process gas containing hydrogen fluoride gas to the recess of the laminated film in the chamber;
A plasma processing apparatus that performs the above steps. A substrate processing system having a first chamber, a plasma generating unit, a second chamber, a gas supply unit, and a control unit, the control unit comprising:
(a) controlling a substrate having a film stack including at least two different silicon-containing films and a mask on the film stack to the first chamber;
(b) controlling, in the first chamber, to etch the laminated film using plasma generated from a first process gas by the plasma generating unit to form a recess in the laminated film;
(c) transferring the substrate from the first chamber to the second chamber, and controlling, in the second chamber, to supply a second process gas including hydrogen fluoride gas to the recess of the laminated film by the gas supply unit;
A substrate processing system that performs the above steps.

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