JP2024054083A - Plasma processing system, plasma processing apparatus and etching method - Google Patents

Abstract

To provide a plasma processing system, a plasma processing apparatus, and an etching method for suppressing a shape abnormality in etching.SOLUTION: In a substrate processing system, a plasma processing apparatus 1 includes a plurality of plasma processing chambers 10, a transfer chamber connected to the processing chambers and having a transport device, and a controller 2. The controller executes processing of: disposing, on a first substrate support, a substrate W including a silicon-containing film having a recess and a mask on the silicon-containing film, the mask having an opening exposing the recess; forming a carbon-containing film on a side wall of the silicon-containing film, the side wall defining the recess; transporting the substrate from a first processing chamber to a second processing chamber via the transport chamber and disposing the substrate on a second substrate support 11; and etching the silicon-containing film at a bottom portion of the recess where the carbon-containing film is formed by using plasma formed from a first processing gas containing hydrogen fluoride gas in the second processing chamber.SELECTED DRAWING: Figure 2

Description

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

Patent document 1 discloses a method for etching a substrate having a polysilicon mask formed on a silicon-containing film.

JP 2016-21546 A

This disclosure provides technology to suppress shape abnormalities in etching.

In one exemplary embodiment of the present disclosure, a plasma processing system is provided. The plasma processing system includes a first processing chamber having a first substrate support, a second processing chamber having a second substrate support and different from the first processing chamber, a transfer chamber connected to the first processing chamber and the second processing chamber and having a transfer device, and a control unit. The control unit performs the following processes: (a) placing a substrate having a silicon-containing film having a recess and a mask on the silicon-containing film on the first substrate support of the first processing chamber, the mask having an opening exposing the recess; (b) forming a carbon-containing film on a sidewall of the silicon-containing film that defines the recess in the first processing chamber; (c) transferring the substrate from the first processing chamber to the second processing chamber via the transfer chamber and placing the substrate on the second substrate support; and (d) etching the bottom of the recess in which the carbon-containing film is formed using plasma generated from a first processing gas containing hydrogen fluoride gas in the second processing chamber.

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

1 is a diagram illustrating an example of the configuration of a plasma processing system. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. FIG. 1 is a diagram for explaining a configuration example of an inductively coupled plasma processing apparatus. 1 is a flow chart illustrating a plasma processing method according to an exemplary embodiment. 2 is a diagram showing an example of a cross-sectional structure of a substrate W provided in a process ST11. FIG. 13 is a diagram showing an example of a cross-sectional structure of the substrate W after being processed in step ST12. 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 another example of the cross-sectional structure of the substrate W after processing at step ST2. FIG. 13 is a diagram showing an example of a cross-sectional structure of a substrate W after a breakthrough process. FIG. 13 is a diagram showing an example of a cross-sectional structure of a substrate W being processed at step ST3. FIG. 13 is a diagram showing an example of a cross-sectional structure of a substrate W being processed at step ST3. FIG. 10 is a flowchart illustrating another example of the present processing method.

Each embodiment of the present disclosure is described below.

In one exemplary embodiment, a plasma processing system is provided. The plasma processing system includes a first processing chamber having a first substrate support, a second processing chamber having a second substrate support and different from the first processing chamber, a transfer chamber connected to the first processing chamber and the second processing chamber and having a transfer device, and a control unit. The control unit performs the following processes: (a) placing a substrate having a silicon-containing film having a recess and a mask on the silicon-containing film on the first substrate support of the first processing chamber, the mask having an opening exposing the recess; (b) forming a carbon-containing film on a sidewall of the silicon-containing film that defines the recess in the first processing chamber; (c) transferring the substrate from the first processing chamber to the second processing chamber via the transfer chamber and placing the substrate on the second substrate support; and (d) etching the bottom of the recess in which the carbon-containing film is formed using plasma generated from a first processing gas including hydrogen fluoride gas in the second processing chamber.

In one exemplary embodiment, the control unit executes a process that repeats a cycle including (a), (b), (c), and (d) multiple times.

In one exemplary embodiment, the control unit controls the pressure in the transfer chamber at least in (c) so that the pressure in the transfer chamber is lower than the pressure in the first processing chamber and the pressure in the second processing chamber.

In one exemplary embodiment, the control unit performs a process prior to (a) in which a recess is formed in the silicon-containing film by etching using plasma generated from a second process gas containing a fluorine-containing gas in the second process chamber or in a third chamber different from the second chamber, to prepare a substrate including a silicon-containing film having a recess.

In one exemplary embodiment, the temperature of the first substrate support in process (b) is higher than the temperature of the second substrate support in process (c).

In one exemplary embodiment, the control unit performs a process of forming a carbon-containing film using a third process gas that includes a carbon-containing gas in (b).

In one exemplary embodiment, the carbon-containing gas is a hydrocarbon gas.

In one exemplary embodiment, the third process gas includes a nitrogen-containing gas.

In one exemplary embodiment, the control unit performs a process in (b) that includes the steps of (b11) supplying a precursor gas to the substrate and adsorbing the precursor gas on the sidewall, and (b12) supplying a reactive gas to the substrate and forming a carbon-containing film by reaction between the precursor gas and the reactive gas.

In one exemplary embodiment, (b) includes (b1) supplying a first deposition gas containing a first organic compound into the first processing chamber, and (b2) supplying a second deposition gas containing a second organic compound different from the first organic compound into the first processing chamber.

In one exemplary embodiment, (b2) forms a carbon-containing film by a reaction that includes polymerization of the first organic compound with the second organic compound.

In one exemplary embodiment, (d) further includes a process for enlarging a dimension of the portion of the recess that is etched in (d).

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, a halogen-containing gas, and a metal-containing gas.

In one exemplary embodiment, process (d) is performed at a temperature of the second substrate support of 0° C. or less.

In one exemplary embodiment, the first processing chamber is coupled to an inductively coupled plasma generating unit, and the second processing chamber is coupled to a capacitively coupled plasma generating unit, and the control unit performs a process of forming a carbon-containing film by generating plasma using the inductively coupled plasma generating unit in the process (b), and performs a process of etching a silicon-containing film by generating plasma using the capacitively coupled plasma generating unit in the process (d).

In one exemplary embodiment, the silicon-containing film is a silicon oxide film, a silicon nitride film, or a polycrystalline silicon film, or a laminate film containing two or more of these.

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

In one exemplary embodiment, a plasma processing system is provided. The plasma processing system includes a first processing chamber having a first substrate support, a second processing chamber having a second substrate support and different from the first processing chamber, and a transfer chamber controller connected to the first processing chamber and the second processing chamber and having a transfer device. The controller controls the following steps: (a) a process of placing a substrate, which includes a silicon-containing film having a recess and a mask on the silicon-containing film, on the first substrate support of the first processing chamber, the mask having an opening exposing the recess; (b) a process of forming a carbon-containing film on a sidewall of the silicon-containing film that defines the recess in the first processing chamber; and (c) a process of placing the substrate on the first substrate support of the first processing chamber. (d) a process of transferring the substrate from the first process chamber to a second process chamber via a transfer chamber and placing the substrate on a second substrate support; and (d) a process of etching the bottom of the recess in the second process chamber in which the carbon-containing film is formed, the process (d) being a process of repeating a cycle including (d1) a step of exposing the substrate to plasma generated from a fourth process gas containing hydrogen fluoride gas, (d2) a step of exposing the substrate to plasma generated from a fifth process gas containing fluorocarbon gas and/or hydrofluorocarbon gas, and (d3) a step of exposing the substrate to plasma generated from a sixth process gas containing hydrogen-containing gas.

In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support disposed in the chamber, a plasma generating unit, and a control unit. The control unit performs the following processes: (a) a process of disposing a substrate including a silicon-containing film having a recess and a mask on the silicon-containing film on the substrate support, the mask having an opening exposing the recess; (b) a process of forming a carbon-containing film on a sidewall of the silicon-containing film that defines the recess in the chamber; and (c) a process of etching the bottom of the recess in which the carbon-containing film is formed, using plasma generated from a process gas including hydrogen fluoride gas in the chamber.

In one exemplary embodiment, an etching method is provided. The etching method includes: (a) disposing a substrate including a silicon-containing film having a recess and a mask on the silicon-containing film on a first substrate support of a first processing chamber, the mask having an opening exposing the recess; (b) forming a carbon-containing film on a sidewall of the silicon-containing film that defines the recess in the first processing chamber; (c) transferring the substrate from the first processing chamber to a second processing chamber via a transfer chamber and disposing the substrate on a second substrate support of the second processing chamber; and (d) etching the bottom of the recess in which the carbon-containing film is formed using plasma generated from a processing gas including hydrogen fluoride gas in the second processing chamber.

Each embodiment of the present disclosure will be described in detail below with reference to the drawings. Note that identical or similar elements in each drawing will be given the same reference numerals, and duplicated explanations will be omitted. Unless otherwise specified, 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 represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

<Configuration Example of Plasma Processing System>
FIG. 1 is a diagram that illustrates a schematic diagram of an example of a plasma processing system (hereinafter referred to as a "substrate processing system PS").

The substrate processing system PS 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 PS 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. A part of the substrate processing module PM may be a capacitively coupled plasma processing apparatus as shown in FIG. 2. That is, at least one of the substrate processing chambers PM1 to PM6 may be coupled to a capacitively coupled plasma generation unit. A part of the substrate processing module PM may be an inductively coupled plasma processing apparatus as shown in FIG. 3. That is, at least one of the substrate processing chambers PM1 to PM6 may be coupled to an inductively coupled plasma generation unit. A part of the substrate processing module PM may be a measurement module, which may measure the thickness of a film formed on the substrate W, the dimensions of a pattern formed on the substrate W, etc., using, for example, an optical method.

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 PS. "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 port 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 port LP.

The controller CT controls each component of the substrate processing system PS 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 PS to perform a given process on the substrate W according to the recipe. The controller CT may perform some or all of the functions of the controller 2 shown in FIG. 2 or FIG. 3.

<Configuration Example of Capacitively Coupled Plasma Processing Apparatus>
An example of the configuration of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described below.

2 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power source 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 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s, and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically 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 (Radio Frequency) power source 31 and/or a DC (Direct Current) 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. In addition to the shower head 13, the gas introduction unit may include 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 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include one or more flow modulation devices to modulate or pulse the flow rate of the at least one process gas.

The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and/or at least one upper electrode. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of a plasma generating unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. 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 section 31a and a second RF generating section 31b. The first RF generating section 31a is coupled to at least one lower electrode and/or at least one upper electrode via at least one impedance matching circuit and 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 section 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 bias DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and/or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses 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.

<Configuration Example of Inductively Coupled Plasma Processing Apparatus>
Next, a configuration example of an inductively coupled plasma processing apparatus will be described as an example of the plasma processing apparatus 1. Fig. 3 is a diagram for explaining the configuration example of an inductively coupled plasma processing apparatus.

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

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 bias electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Also, at least one RF/DC electrode coupled to 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 bias electrode. Note that the conductive member of the base 1110 and the at least one RF/DC electrode may function as multiple bias electrodes. Also, the electrostatic electrode 1111b may function as a bias electrode. Thus, the substrate support 11 includes at least one bias 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 gas introduction section is configured to introduce at least one processing gas from the gas supply section 20 into the plasma processing space 10s. In one embodiment, the gas introduction section includes a center gas injector (CGI) 13. The center gas injector 13 is disposed above the substrate support 11 and attached to a central opening formed in the dielectric window 101. The center gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet 13c. The processing gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas inlet 13c. In addition to or instead of the center gas injector 13, the gas introduction section may include one or more side gas injectors (SGI) attached to one or more openings formed in the sidewall 102.

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

The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one bias electrode and the antenna 14. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. 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 bias electrode, a bias potential is generated on the substrate W, and ions 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 the antenna 14 via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

The second RF generating unit 31b is coupled to at least one bias electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a 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 generating unit 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one bias electrode. 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 bias DC generator 32a. In one embodiment, the bias DC generator 32a is connected to at least one bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to the at least one bias electrode.

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

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

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.

<An example of a plasma treatment method>
FIG. 4 is a flow chart showing an example of a plasma processing method (hereinafter, also referred to as the present processing method) according to an exemplary embodiment. As shown in FIG. 4, the present processing method includes a step ST1 of preparing a substrate, a step ST2 of forming a carbon-containing film on the substrate, and a step ST3 of etching the substrate. The processing in each step may be performed in two or more of the substrate processing modules PM included in the substrate processing system PS shown in FIG. 1. The substrate processing module PM may be the plasma processing apparatus 1 shown in FIG. 2 and/or FIG. 3. For example, the steps ST1 and ST3 may be performed in the capacitively coupled plasma processing apparatus 1 shown in FIG. 2, and the step ST2 may be performed in the inductively coupled plasma processing apparatus 1 shown in FIG. 3. In the following, a case where the control unit 2 controls each part of the substrate processing system PS and the plasma processing apparatus 1 to perform the present processing method on the substrate W will be described as an example.

(Step ST1: Preparation of substrate)
4, step ST1 includes step ST11 of providing a substrate W, and step ST12 of etching the substrate W to form a recess. First, in step ST11, the substrate W is provided in a plasma processing space 10s of the capacitively coupled plasma processing apparatus 1 shown in FIG. 2. The substrate W is provided on a central region 111a of a substrate support 11. Then, the substrate W is held on the substrate support 11 by an electrostatic chuck 1111.

Figure 5 is a diagram showing an example of a cross-sectional structure of a substrate W provided in process ST11. As shown in Figure 5, the substrate W has a silicon-containing film SF and a mask MK formed on the silicon-containing film SF. The silicon-containing film SF may be formed on an undercoat film UF. The substrate W may be used in the manufacture of semiconductor devices. Semiconductor devices include, for example, semiconductor memory devices such as DRAMs and 3D-NAND flash memories.

The base film UF is, for example, 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 silicon-containing film SF is a film to be etched by the present processing method. The silicon-containing film SF may be, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbonitride film, a polycrystalline silicon film, or a carbon-containing silicon film. The silicon-containing film SF may be formed by stacking a plurality of films. For example, the silicon-containing film SF may be formed by alternately stacking a silicon oxide film and a silicon nitride film. For example, the silicon-containing film SF may be formed by alternately stacking a silicon oxide film and a polycrystalline silicon film. For example, the silicon-containing film SF may be a stacked film including a silicon nitride film, a silicon oxide film, and a polycrystalline silicon film. For example, the silicon-containing film SF may be formed by stacking a silicon oxide film and a silicon carbonitride film. For example, the silicon-containing film SF may be a stacked film including a silicon oxide film, a silicon nitride film, and a silicon carbonitride film. The silicon-containing film may contain at least one element selected from the group consisting of phosphorus (p), nitrogen (N), and boron (B).

The mask MK is formed from a material having a lower etching rate for the plasma generated in step ST12 or step ST3 than the silicon-containing film SF. The mask MK may be formed from, for example, a carbon-containing material. In one example, the mask MK is an amorphous carbon film, a photoresist film, or a SOC film (spin-on carbon film). The mask MK may be a metal-containing film containing at least one metal selected from the group consisting of, for example, tungsten, molybdenum, titanium, and ruthenium. In one example, the mask MK contains tungsten carbide or tungsten silicide. The mask MK may be a single-layer mask consisting of one layer, or may be a multilayer mask consisting of two or more layers.

As shown in FIG. 5, the mask MK defines at least one opening OP on the silicon-containing film SF. The opening OP is a space on the silicon-containing film SF and is surrounded by a sidewall SS1 of the mask MK. That is, the upper surface of the silicon-containing film SF 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. 3. 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 SS1, which 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 of the films constituting the substrate W (undercoat film UF, silicon-containing film SF, mask MK) may be formed by CVD, ALD, spin coating, or the like. The mask MK may be formed by lithography. The opening OP of the mask MK may be formed by etching the mask MK. Each of the films may be flat or may have irregularities. The substrate W may further have another film below the undercoat film UF. In this case, a recess having a shape corresponding to the opening OP may be formed in the silicon-containing film SF and undercoat film UF, and used as a mask for etching the other film.

At least a part of the process of forming each film on the substrate W may be performed in the space of the plasma processing chamber 10 in which step ST1 is performed. In one example, when the mask MK is etched to form an opening OP, the step may be performed in the plasma processing chamber 10. That is, the opening OP and the etching of the silicon-containing film SF in step ST12 described later may be performed consecutively in the same chamber. In addition, after all of the films on the substrate W are formed in an apparatus or chamber external to the plasma processing apparatus 1, the substrate W may be provided by being loaded into the plasma processing space 10s of the plasma processing apparatus 1 and placed on the substrate support 11.

After the substrate W is provided to the central region 111a of the substrate support 11, the temperature of the substrate support 11 is adjusted to a set temperature by a temperature control module. The set temperature may be, for example, a temperature of 70°C or less (for example, room temperature). Also, for example, the set temperature may be 0°C or less, -10°C or less, -20°C or less, -30°C or less, -40°C or less, -50°C or less, -60°C or less, or -70°C or less. In one example, adjusting or maintaining the temperature of the substrate support 11 includes setting the temperature of the heat transfer fluid flowing through the flow path 1110a or the heater temperature to a set temperature, or to a temperature different from the set temperature. The timing at which the heat transfer fluid starts to flow through the flow path 1110a may be before or after the substrate W is placed on the substrate support 11, or may be the same as the substrate W. Also, the temperature of the substrate support 11 may be adjusted to the set temperature before the process ST11. That is, the substrate W may be provided to the substrate support 11 after the temperature of the substrate support 11 is adjusted to the set temperature.

Next, in step ST12, the silicon-containing film SF is etched using plasma generated from the first processing gas. First, the first processing gas is supplied from the gas supply unit 20 into the plasma processing space 10s. The first processing gas may be selected so that the silicon-containing film SF can be etched with a sufficient selectivity to the mask MK. The first processing gas may contain one or more of the same types of gases as the third processing gas used in the etching in step ST3 described later. The first processing gas may contain a fluorine-containing gas. In one example, the fluorine-containing gas may be hydrogen fluoride gas (HF gas). The first processing gas may further contain one or more gases selected from the group consisting of a phosphorus-containing gas, a carbon-containing gas, a halogen-containing gas other than fluorine, an inert gas, and a metal-containing gas such as tungsten.

During the process in step ST12, the gases contained in the first process gas and their flow rates (partial pressures) may be changed or may not be changed. For example, when the silicon-containing film SF is composed of a laminated film made of different types of silicon-containing films, the composition of the process gas and the flow rates of each gas may be changed as the etching progresses, i.e., depending on the type of film to be etched. During the process in step ST12, the temperature of the substrate support part 11 may be maintained at the set temperature adjusted in step ST11. The set temperature of the substrate support part 11 may also be changed depending on the type of the first process gas and/or the silicon-containing film. For example, when the first process gas contains a fluorine-containing gas, the set temperature of the substrate support part 11 may be 0°C or lower.

In step ST12, a source RF signal is then supplied to the lower electrode of the substrate support 11 and/or the upper electrode of the shower head 13. This generates a high-frequency electric field between the shower head 13 and the substrate support 11, and plasma is generated from the processing gas in the plasma processing space 10s. The active species, such as ions and radicals, in the plasma etches the portion of the silicon-containing film SF that is not covered by the mask MK (the portion exposed at the opening OP). The etching in step ST12 continues until the recess RC reaches a given depth. The etching in step ST12 is terminated at least before the base film UF is exposed.

Figure 6 is a diagram showing an example of the cross-sectional structure of the substrate W after processing in step ST12. As shown in Figure 6, the etching in step ST12 etches the portion of the silicon-containing film SF exposed in the opening OP in the depth direction (the direction from top to bottom in Figure 4), forming a recess RC.

In step ST12, a bias signal may be supplied to the lower electrode of the substrate support 11. The bias signal may be a bias RF signal supplied from the second RF generating unit 31b. The bias signal may also be a bias DC signal supplied from the DC generating unit 32a. 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 both 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%. The duty ratio is the proportion of the period during which the power or voltage level is high in the period of the pulse wave. 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, provided that the potential of the substrate W is set to provide a potential difference between the plasma and the substrate to attract ions.

In addition, in step ST12, the supply and stopping of at least one of the source RF signal and the bias signal may be alternately repeated. For example, the supply and stopping 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 stopping of the source RF signal are alternately repeated. For example, the supply and stopping of both the source RF signal and the bias signal may be alternately repeated.

In this manner, in step ST1, a substrate W including a silicon-containing film SF having a recess RC and a mask MK is prepared on the substrate support 11 of the plasma processing chamber 10. In the above example, the recess RC is formed after the substrate W is provided on the substrate support 11. However, the substrate W may be prepared by forming the recess RC in the substrate W in an external device or chamber of the capacitively coupled plasma processing apparatus 1 shown in FIG. 2, and then providing the substrate W on the substrate support 11 of the capacitively coupled plasma processing apparatus 1 shown in FIG. 2. The external device may be one of the substrate processing modules PM included in the substrate processing system PS.

(Step ST2: Forming a carbon-containing film on a substrate)
In step ST2, a carbon-containing film CF is formed on the substrate W.
Step ST2 includes step ST21 of transporting the substrate W to the plasma processing chamber 10 of the inductively coupled plasma processing apparatus 1 shown in FIG. 3, and step ST22 of forming a carbon-containing film on the substrate W in the plasma processing chamber 10. The plasma processing chamber 10 of the inductively coupled plasma processing apparatus 1 shown in FIG. 3 is an example of a first chamber. In step ST21, the substrate W may be transported via a transport apparatus having a transport chamber. As an example, the transport chamber is a chamber included in the transport module TM. The pressure inside the transport chamber may be lower than that outside the transport chamber. The inside of the transport chamber may be maintained at a reduced pressure atmosphere that is the same as or similar to that of the chamber used in step ST1 and/or the chamber used in step ST2.

In step ST21, the substrate W is transferred to the plasma processing chamber 10 of the inductively coupled plasma processing apparatus 1 shown in FIG. 3 and placed on the substrate support 11. Then, in step ST22, a carbon-containing film CF is formed on the substrate W. The carbon-containing film CF may be formed by various methods. As an example, a method using plasma CVD will be described below. First, a second processing gas containing a carbon-containing gas is supplied from the gas supply unit 20 into the plasma processing space 10s. The carbon-containing gas may be, for example, a hydrocarbon gas. In one example, the _hydrocarbon gas is at least _{one gas selected from the group consisting of CH4 gas, C2H2 gas , C2H4} gas, and _C3H6 gas. Note that the carbon-containing gas may also be one containing fluorine, such as _CH3F gas and _C4F6 gas. In this case _, conditions are selected _that allow deposition to be more dominant than etching of the silicon-containing film SF. The second processing gas may further contain a nitrogen-containing gas, such as _N2 gas or _NH3 gas. The second process gas may further include a hydrogen-containing gas, such as _H2 gas.

Next, a source RF signal is supplied to the antenna 14. This generates a plasma from the second processing gas in the plasma processing space 10s. Then, carbon or activated species containing carbon generated in the plasma are adsorbed onto the surface of the substrate W, forming a carbon-containing film CF on the surface of the substrate W.

In addition, in step ST2, the temperature of the substrate support part 11 may be set to a temperature higher than the temperature of the substrate support part 11 in step ST12 or step ST3. The set temperature may be, for example, 0°C or higher.

In addition, in process ST2, plasma may be generated so as to suppress the incidence of ions on the substrate W. For example, a bias signal does not need to be supplied.

In addition to the above-mentioned step of generating plasma from the second processing gas, the process ST2 may include a step of generating plasma from a processing gas containing a nitrogen-containing gas such as _N2 gas or _NH3 gas. This can prevent carbon in the plasma from excessively depositing on the substrate W and blocking the opening OP. In the process ST2, the step of generating plasma from the second processing gas and the step of generating plasma from the processing gas containing the nitrogen-containing gas may be alternately repeated multiple times. The processing gas containing the nitrogen-containing gas may further contain a hydrogen-containing gas such as _H2 gas.

7 is a diagram showing an example of a cross-sectional structure of the substrate W after the process of step ST2. As shown in FIG. 7, a carbon-containing film CF is formed on the substrate W. The carbon-containing film CF is formed on at least a part of the side wall SS2 of the silicon-containing film SF that defines the recess RC. The part may be a part with a high collision frequency of active species (including those reflected by the side wall SS1 of the mask MK) in the plasma that enters the opening OP during the etching in step ST3. For example, the part may be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the side wall SS1 of the silicon-containing film in the depth direction. As shown in FIG. 7, the carbon-containing film CF may be formed on the upper surface of the mask MK and the side wall SS1 that defines the opening OP to a part of the side wall SS2 of the silicon-containing film SF. As described later, the carbon-containing film CF may function as a protective film against etching during the etching in step ST3.

The carbon-containing film CF may be formed by ALD or subconformal ALD instead of plasma CVD.

ALD includes a first step and a second step. First, in the first step, a precursor gas containing an organic compound is supplied to the substrate W. The organic compound may contain at least one selected from the group consisting of, for example, epoxides, carboxylic acids, carboxylic acid halides, carboxylic acid anhydrides, isocyanates, and phenols. In the first step, the precursor gas is adsorbed onto the surfaces of the mask MK and the silicon-containing film SF. In the first step, plasma may be generated from the precursor gas.

Next, in the second step, a reactive gas is supplied to the substrate W. The reactive gas is a gas that reacts with the precursor gas adsorbed on the surface of the substrate W. The reactive gas may include at least one selected from the group consisting of an inorganic compound gas having an NH bond, an inert gas, a mixed gas of N ₂ gas and H ₂ gas, H ₂ O gas, and a mixed gas of H ₂ gas and O ₂ gas. The inorganic compound gas having an NH bond may be, for example, at least one gas selected from N ₂ H ₂ gas, N ₂ H ₂ gas, and NH ₃ gas. The precursor gas and the reactive gas react with each other to form a carbon-containing film CF by the second step. In the second step, plasma may be generated from the reactive gas.

Note that an inert gas or the like may be supplied to the substrate W between the first and second steps and/or after the second step. This allows excess precursor gas and reactant gas to be purged (purge step). In ALD, a carbon-containing film CF is formed by a self-controlled adsorption and reaction of a specific material with a substance present on the surface of the substrate W. In ALD, a conformal carbon-containing film CF is usually formed by providing a sufficient processing time.

The carbon-containing film CF may be formed by MLD. That is, the carbon-containing film CF may be formed by polymerization of an organic compound. MLD includes a first step and a second step. First, in the first step, a first film formation gas is supplied to the substrate W. The first film formation gas contains a first organic compound. In the first step, the first film formation gas is adsorbed onto the surface of the substrate W. The surface may include a side wall SS1, a side wall SS2, and a bottom surface BT.

Next, in the second step, a second deposition gas is supplied to the substrate W. The second deposition gas contains a second organic compound. In the second step, the first organic compound adsorbed on the surface of the substrate W is polymerized with the second organic compound. This polymerization forms a carbon-containing film CF on the surface of the substrate W.

Note that an inert gas or the like may be supplied to the substrate W between the first and second steps and/or after the second step. This allows the first organic compound and/or the second organic compound that have formed in excess on the surface of the substrate W to be removed.

In one embodiment, the first organic compound may be a monofunctional isocyanate or a difunctional isocyanate, and the second organic compound may be a monofunctional amine or a difunctional amine. In one embodiment, the organic compound obtained by polymerization (addition condensation) of an isocyanate and an amine may be a compound having a urea bond.

In one embodiment, the first organic compound may be a monofunctional isocyanate or a difunctional isocyanate, and the second organic compound may be a monofunctional compound having a hydroxyl group or a difunctional compound having a hydroxyl group. Also, in one embodiment, the organic compound obtained by polymerization (polyaddition) of an isocyanate and a compound having a hydroxyl group may be a compound having a urethane bond.

In one embodiment, the first organic compound may be a monofunctional carboxylic acid or a difunctional carboxylic acid, and the second organic compound may be a monofunctional amine or a difunctional amine. In one embodiment, the organic compound obtained by polymerization (polycondensation) of a carboxylic acid and an amine may be a compound having an amide bond. As an example, the compound having an amide bond may be a polyamide.

In one embodiment, the first organic compound may be a monofunctional carboxylic acid or a difunctional carboxylic acid, and the second organic compound may be a monofunctional compound having a hydroxyl group or a difunctional compound having a hydroxyl group. In one embodiment, the organic compound obtained by polymerization (polycondensation) of a carboxylic acid and a compound having a hydroxyl group may be a compound having an ester bond. As an example, a compound having a polyester bond may be an ester.

In one embodiment, the first organic compound may be a carboxylic acid anhydride and the second organic compound may be an amine. In one embodiment, the organic compound obtained by polymerization of the carboxylic acid anhydride and the amine may be an imide compound.

In one embodiment, the first organic compound can be bisphenol A and the second organic compound can be diphenyl carbonate.
be able to.

In one embodiment, the first organic compound can be bisphenol A and the second organic compound can be epichlorohydrin.

Figure 8A is a diagram showing another example of the cross-sectional structure of the substrate W after processing in step ST2. Figure 8A shows an example of a conformal carbon-containing film CF formed by ALD or MLD. As shown in Figure 8A, the carbon-containing film CF is formed uniformly on the upper surface of the mask MK and the sidewall SS1 that defines the opening OP, and on the entire sidewall SS2 and bottom surface BT that define the recess RC of the silicon-containing film SF.

In the case where a conformal carbon-containing film CF is formed in the step ST2, the step ST2 may further include a step (breakthrough step) of removing the carbon-containing film formed on the bottom surface BT of the recess RC. The breakthrough step may be performed by generating plasma from a process gas containing, for example, N ₂ gas and H ₂ gas. At this time, a bias signal may be supplied to the substrate support 11.

Figure 8B is a diagram showing an example of the cross-sectional structure of the substrate W after the breakthrough process. As shown in Figure 8B, the carbon-containing film CF formed on the bottom surface BT of the silicon-containing film SF is removed, and the bottom surface, i.e., the portion to be etched in step ST3, is exposed to the recess RC.

Sub-conformal ALD is a technique in which processing conditions are set so as not to complete self-limiting adsorption or reaction on the surface of the substrate W. There are at least the following two processing modes in sub-conformal ALD.
(i) After the precursor gas is adsorbed onto the entire surface of the substrate W, the reaction gas is controlled so as not to reach the entire surface of the precursor gas adsorbed on the substrate W.
(ii) After the precursor gas is adsorbed only on a portion of the surface of the substrate W, the reactive gas is reacted with only the precursor gas adsorbed on the surface of the substrate W.

Subconformal ALD forms a carbon-containing film CF whose thickness decreases along the depth direction of the recess RC. If a carbon-containing film is also formed on the bottom surface BT of the silicon-containing film SF, the breakthrough process described above may be performed.

In step ST22, the carbon-containing film CF may be formed by generating plasma from a processing gas containing a gas of a low vapor pressure material, and depositing a flowable film generated from the low vapor pressure material by the plasma in the recess RC. In one example, the gas of the low vapor pressure material includes at least one gas selected from the group consisting of C ₃ F ₆ gas, C ₄ F ₆ gas, C ₄ F ₈ gas, isopropyl alcohol (IPA) gas, C ₃ H ₂ F ₄ gas, and C ₄ H ₂ F ₆ gas. The gas of the low vapor pressure material may be a gas that reaches a vapor pressure at a temperature equal to or higher than the temperature indicated by the temperature-vapor pressure curve of C ₄ F _8. In this case, the pressure in the plasma processing space 10s may be, for example, 50 mT (6.7 Pa) or more, and the substrate support 11 may be set to a temperature of 0° C. or less.

In addition to the above, the carbon-containing film CF may be formed by various methods such as thermal CVD.

(Step ST3: Etching the substrate)
In step ST3, the silicon-containing film SF is etched. Step ST3 includes step ST31 of transporting the substrate W to the plasma processing chamber 10 of the capacitively coupled plasma processing apparatus 1 shown in FIG. 2, and step ST32 of etching the substrate W in the plasma processing chamber 10. The plasma processing chamber 10 of the capacitively coupled plasma processing apparatus 1 shown in FIG. 2 is an example of a second chamber. In step ST31, the substrate W may be transported via a transport apparatus having a transport chamber, as in step ST21. As an example, the transport chamber is a chamber included in the transport module TM. The pressure inside the transport chamber may be lower than the pressure outside the transport chamber. The pressure inside the transport chamber may be maintained at the same or approximately the same reduced pressure atmosphere as the chamber used in step ST1 and/or step ST3 and/or the chamber used in step ST2. Step ST3 may also be performed by the inductively coupled plasma processing apparatus 1 shown in FIG. 3.

In step ST31, the substrate W is transported to the plasma processing chamber 10 of the capacitively coupled plasma processing apparatus 1 shown in FIG. 2 and placed on the substrate support 11. Then, in step ST32, the silicon-containing film SF is etched. First, a third processing gas containing HF gas is supplied from the gas supply unit 20 into the plasma processing space 10s. During the processing in step ST3, the gases contained in the third processing gas and their flow rates (partial pressures) may or may not be changed. For example, when the silicon-containing film SF is composed of a stacked film made of different types of silicon-containing films, the composition of the third processing gas and the flow rates of each gas may be changed as the etching progresses, that is, depending on the type of film to be etched. In step ST3, the temperature of the substrate support 11 may be appropriately set depending on the type of processing gas, the type of silicon-containing film, etc. For example, when the processing gas contains a fluorine-containing gas, the set temperature of the substrate support 11 may be 0°C or lower.

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. This generates a high-frequency electric field between the shower head 13 and the substrate support 11, and generates plasma from the third processing gas in the plasma processing space 10s.

In step ST3, a bias signal may be supplied to the lower electrode of the substrate support 11. In this case, a bias potential is generated between the plasma and the substrate W, and active species such as ions and radicals in the plasma are attracted to the substrate W, which may promote etching of the silicon-containing film SF. The bias signal may be a bias RF signal supplied from the second RF generating unit 31b. The bias signal may also be a bias DC signal supplied from the DC generating unit 32a.

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 step ST3, 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.

The fluorine-containing gas contained in the third process gas may be, for example, a hydrofluorocarbon gas other than HF 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 fluorine-containing gas 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. ) .}

When the fluorine-containing gas is HF gas, the HF gas may have the highest flow rate (partial pressure) among the third process gas (if the third process gas contains an inert gas, all gases 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 third process gas (if the third process gas contains an inert gas, 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 third process gas. In one example, the flow rate of the HF gas is adjusted to 70 vol.% or more and 96 vol.% or less with respect to the total flow rate of the third process gas.

The third process gas may further include a tungsten-containing gas. The tungsten-containing gas included in the third process gas may be, for example, a gas containing tungsten and halogen. The tungsten-containing gas is, 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, at least one of WF ₆ gas and WCl ₆ gas may be used. The flow rate of the tungsten-containing gas may be 5 vol% or less of the total flow rate of the third process gas. The third process gas may contain 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.

The third process gas may further 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 process gas may contain one or more of the above phosphorus-containing molecules as at least one phosphorus-containing molecule. For example, the second 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 third 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.

The phosphorus-containing gas may _{be PClaFb (a is an integer of 1 or more, b is an integer of 0 or more, and a+b is an integer of 5 or less) gas or PCcHdFe ( d and e} are integers of 1 or more and 5 or less, and c is an integer of 0 or more and 9 or less) 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.

The _phosphorus -containing gas _may be _PClcFdCeHf (c, d, e, and f are each an integer of 1 or more) gas. 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.

The phosphorus-containing gas may be a phosphine-based gas, which may include phosphine (PH ₃ ), a compound in which at least one hydrogen atom of phosphine is substituted 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.

The flow rate of the phosphorus-containing gas may be 20% by volume or less, 10% by volume or less, or 5% by volume or less of the total flow rate of the third process gas.

The third process gas may further include a carbon-containing gas. The carbon-containing gas may be, for example, either 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 having _{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 third process gas may further include an oxygen-containing gas. The oxygen-containing gas may be, for example, at least one gas selected from the group consisting of _O2 , CO, _CO2 , _H2O , and _H2O2 . In one example, _the oxygen-containing gas may be an oxygen-containing gas other than _H2O , for example, at least one gas selected from the group consisting of _O2 , CO, _CO2 , and _{H2O2 .} The flow rate of the oxygen-containing gas may be adjusted according to the flow rate of the carbon-containing gas.

The third process gas may further 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 , _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.

The third 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, step ST32 may include multiple steps of exposing the substrate W to different types of plasma. In one embodiment, step ST32 may include a step of generating plasma from a fourth process gas, a step of generating plasma from a fifth process gas, and a step of generating plasma from a sixth process gas. The step of generating plasma from the fourth process gas, the step of generating plasma from the fifth process gas, and the step of generating plasma from the sixth process gas may be performed repeatedly.

In the step of generating plasma from the fourth process gas, the fourth process gas may contain hydrogen fluoride gas. The step of generating plasma from the fourth process gas may be performed under the same conditions as step ST32. In one embodiment, the fourth process gas may contain, in addition to hydrogen fluoride gas, one or more gases that may be contained in the third process gas. By exposing the substrate W to the plasma generated from the fourth process gas, the silicon-containing film SF may be etched at the bottom BT of the recess RC (see FIG. 8B).

In the step of generating plasma from the fifth process gas, the fifth process gas may include a fluorocarbon gas and/or a hydrofluorocarbon gas. The step of generating plasma from the fourth process gas may be performed under the same conditions as in step ST22. As an example, the fifth process gas may include CH _4. In one embodiment, the fifth process gas may include one or more gases that may be included in the second process gas in addition to the fluorocarbon gas and/or the hydrofluorocarbon gas. By exposing the substrate W to the plasma generated from the fifth process gas, a carbon-containing film may be formed on the surface of the portion etched in the step of generating plasma from the fourth process gas. As an example, the thickness of the carbon-containing film may be 1 to 10 nm. In one embodiment, the carbon-containing film may be formed by ALD or MLD.

In the step of generating plasma from the sixth process gas, the sixth process gas may include a hydrogen-containing gas. As an example, the hydrogen-containing gas may include _H2 . As an example, a flow rate ratio of H2 to a total flow rate of the sixth process gas may be 50% or more. As an example, a time period for exposing the substrate W to the plasma generated from the sixth process gas may be 1 second to 30 seconds. In the step of generating plasma from the sixth process gas, a pressure in the plasma processing chamber 10 may be 1 mTorr to 1,000 mTorr. By exposing the substrate W to the plasma generated from the sixth process gas, fluorine atoms contained in the carbon-containing film generated from the fifth process gas may be replaced with hydrogen atoms.

In step ST32, the step of generating plasma from the fourth process gas, the step of generating plasma from the fifth process gas, and the step of generating plasma from the sixth process gas are repeatedly performed, so that the recess RC can be formed deeper in the silicon-containing film SF while protecting the sidewall SS2 of the silicon-containing film SF. This makes it possible to suppress shape abnormalities in the recess RC formed in the silicon-containing film SF.

Figure 9A is a diagram showing an example of a cross-sectional structure of the substrate W during processing of step ST3. As shown in Figure 9A, the portion of the silicon-containing film SF that is not covered by the mask MK (the portion exposed at the opening OP) is etched in the depth direction by active fluorine species in the plasma. Here, at least a portion of the carbon-containing film CF can function as a protective film that protects the side wall SS2 of the silicon-containing film SF that defines the recess RC. Therefore, the side wall SS2 of the silicon-containing film SF is prevented from being removed by etching during processing of step ST3.

Note that step ST3 may include a step of improving the shape of the recess RC. As an example, as shown in FIG. 9B, the width dimension of the recess RC in the portion etched in step ST3 may be narrower than the width dimension of the recess RC in the portion protected by the carbon-containing film CF. In this case, step ST3 may further include a step of expanding the dimension of the recess RC in the portion etched in step ST3. As a result, for example, even if the recess RC formed in step ST3 has a tapered shape as shown in FIG. 9B, the cross-sectional shape of the recess RC can be made closer to a vertical shape as shown in FIG. 9A. Note that in one embodiment, the step of expanding the dimension of the recess RC may be performed by changing the parameters of step ST3. As an example, the change in the parameters may be to reduce the pressure in the plasma processing chamber 10 and/or to reduce the flow rate ratio of the hydrogen fluoride gas to the total flow rate of the processing gas.

As described above, in this processing method, in step ST3, the silicon-containing film SF is etched in the depth direction while the lateral etching of the sidewall SS2 of the silicon-containing film SF is suppressed. This makes it possible for this processing method to suppress the occurrence of shape abnormalities due to etching, such as bowing.

Figure 10 is a flowchart showing another example of the present processing method. As shown in Figure 10, in this example, after step ST3, it is determined whether a given condition is satisfied, and steps ST2 and ST3 are repeated until it is determined that the given condition is satisfied. Except for this point, this example is similar to the flowchart shown in Figure 2.

The given conditions in step ST4 may be appropriately determined. For example, the given conditions may be conditions related to the number of cycles when step ST2 and step ST3 are one cycle. That is, it may be determined whether the number of cycles has reached a preset number of repetitions (e.g., 10, 20, 30, 50, etc.), and step ST2 and step ST3 may be repeated until the number of repetitions is reached. The number of repetitions may be set based on the film thickness of the silicon-containing film SF (depth to be etched).

For example, the given condition may be a condition regarding the dimensions of the recess RC after processing by step ST3. That is, after step ST3, it may be determined whether the depth or bottom width of the recess RC has reached a given value or range, and the cycle of steps ST2 and ST3 may be repeated until the given value or range is reached. The dimensions of the recess RC may be measured by an optical measuring device. Note that, when this processing method processes multiple substrates W as one unit (hereinafter referred to as a "lot"), the repetition of the cycle may be determined based on the dimensions of the recess RC after processing only for one or more substrates W included in the lot. At this time, the number of repeated cycles may be stored and used as a given condition for other substrates included in the lot. That is, for the other substrates, it may be determined whether the stored number of cycles has been reached, and if not, steps ST2 and ST3 may be repeated.

<Example>
Next, examples of the present processing method will be described. The present disclosure is not limited to the following examples.

Example 1
In Example 1, the processing method was performed according to the flowchart shown in Fig. 4 using a substrate W similar to the substrate W shown in Fig. 5, and a recess RC was formed in the silicon-containing film SF. The processing gas and the flow rate thereof used in step ST12 were the same as the processing gas and the flow rate thereof used in step ST32.

a) Step ST12
Equipment: Capacitively coupled plasma processing equipment (Figure 2)
Processing gas: HF, hydrofluorocarbon, phosphorus-containing gas, halogen-containing gas Set temperature of substrate support: -70°C
b) Step ST22
Equipment: Inductively coupled plasma processing equipment (Figure 3)
Process gas: Hydrocarbon, hydrogen-containing gas, nitrogen-containing gas c) Step ST32
Equipment: Capacitively coupled plasma processing equipment (Figure 2)
Processing gas: HF, hydrofluorocarbon, phosphorus-containing gas, halogen-containing gas Set temperature of substrate support: -70°C

(Reference Example 1)
In Reference Example 1, a recess RC was formed in the silicon-containing film SF using the same substrate W and the same capacitively coupled plasma processing apparatus as in Example 1. The process gas and its flow rate used in Reference Example 1 were the same as the process gas and its flow rate used in steps ST12 and ST32 in Example 1. The process time in Reference Example 1 was the same as the sum of the process time in step ST12 and the process time in step ST32 in Example 1.

Equipment: Capacitively coupled plasma processing equipment (Figure 2)
Processing gas: HF, hydrofluorocarbon, phosphorus-containing gas, halogen-containing gas Set temperature of substrate support: -70°C

After completion of step ST12 and step ST32 in Example 1, and after completion of Reference Example 1, the maximum value of the CD (Critical Dimension) in the depth direction of the recess RC was measured.

In Example 1, there was no significant difference between the maximum CD value after completion of step ST32 and the maximum CD value of the recess RC after completion of step ST12, and the occurrence of bowing was limited. In contrast, the maximum CD value after completion of Reference Example 1 was approximately 1.2 times the maximum CD value after completion of step 32 in Example 1, and the occurrence of bowing was significant. Thus, in Example 1, bowing of the recess RC was significantly suppressed compared to Reference Example 1.

Embodiments of the present disclosure further include the following aspects:

(Appendix 1)
1. A plasma processing system comprising:
a first processing chamber having a first substrate support;
a second process chamber having a second substrate support, the second process chamber being different from the first process chamber;
a transfer chamber connected to the first processing chamber and the second processing chamber and having a transfer device;
A control unit;
Equipped with
The control unit is
(a) placing a substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film on the first substrate support of the first process chamber, the mask having an opening exposing the recess;
(b) forming a carbon-containing film on sidewalls of the silicon-containing film defining the recess in the first processing chamber;
(c) transferring the substrate from the first processing chamber to the second processing chamber via a transfer chamber and placing the substrate on the second substrate support;
(d) etching the bottom of the recess on which the carbon-containing film is formed, using plasma generated from a first process gas containing hydrogen fluoride gas in the second process chamber;
A plasma processing system.

(Appendix 2)
2. The plasma processing system of claim 1, wherein the control unit executes a process of repeating a cycle including (a), (b), (c), and (d) a plurality of times.

(Appendix 3)
3. The plasma processing system of claim 1, wherein the controller controls the pressure in the transfer chamber so that the pressure in the transfer chamber is lower than the pressure in the first processing chamber and the pressure in the second processing chamber, at least in (c).

(Appendix 4)
3. The plasma processing system according to claim 1, wherein the control unit performs a process, prior to (a), of forming the recess in the silicon-containing film by etching in the second processing chamber or in a third chamber different from the second chamber using plasma generated from a second processing gas containing a fluorine-containing gas, to prepare the substrate including the silicon-containing film having the recess.

(Appendix 5)
4. The plasma processing system of claim 1, wherein a temperature of the first substrate support in the process of (b) is higher than a temperature of the second substrate support in the process of (c).

(Appendix 6)
6. The plasma processing system according to claim 1, wherein in (b), the control unit performs a process of forming the carbon-containing film using a third process gas including a carbon-containing gas.

(Appendix 7)
7. The plasma processing system of claim 6, wherein the carbon-containing gas is a hydrocarbon gas.

(Appendix 8)
7. The plasma processing system of claim 6, wherein the third process gas comprises a nitrogen-containing gas.

(Appendix 9)
The control unit, in (b),
(b11) supplying a precursor gas to the substrate and allowing the precursor gas to be adsorbed on the side wall;
(b12) supplying a reactive gas to the substrate and forming the carbon-containing film by a reaction between the precursor gas and the reactive gas;
2. The plasma processing system of claim 1, further comprising:

(Appendix 10)
The (b) is
(b1) supplying a first deposition gas containing a first organic compound into the first processing chamber;
(b2) supplying a second deposition gas into the first process chamber, the second deposition gas including a second organic compound different from the first organic compound;
2. The plasma processing system of claim 1, comprising:

(Appendix 11)
11. The plasma processing system of claim 10, wherein (b2) forms the carbon-containing film by a reaction including polymerization of the first organic compound and the second organic compound.

(Appendix 12)
2. The plasma processing system of claim 1, wherein (d) further comprises: enlarging a dimension of the portion of the recess that is etched in (d).

(Appendix 13)
13. The plasma processing system of claim 1, wherein the first process gas further comprises a phosphorus-containing gas.

(Appendix 14)
14. The plasma processing system of claim 1, wherein the first process gas further comprises at least one gas selected from the group consisting of a carbon-containing gas, a halogen-containing gas, and a metal-containing gas.

(Appendix 15)
15. The plasma processing system of claim 14, wherein the process (d) is performed at a temperature of the second substrate support of 0° C. or less.

(Appendix 16)
the first processing chamber is coupled to an inductively coupled plasma generator;
the second processing chamber is coupled to a capacitively coupled plasma generating unit;
16. The plasma processing system according to claim 1, wherein the control unit performs a process of forming the carbon-containing film by generating plasma using an inductively coupled plasma generating unit in the process (b), and performs a process of etching the silicon-containing film by generating plasma using the capacitively coupled plasma generating unit in the process (d).

(Appendix 17)
17. The plasma processing system of claim 1, wherein the silicon-containing film is a silicon oxide film, a silicon nitride film, or a polycrystalline silicon film, or a laminate film including two or more of these.

(Appendix 18)
18. The plasma processing system of any one of claims 1 to 17, wherein the mask is a carbon-containing film or a metal-containing film.

(Appendix 19)
1. A plasma processing system comprising:
a first processing chamber having a first substrate support;
a second process chamber having a second substrate support, the second process chamber being different from the first process chamber;
a transfer chamber control unit connected to the first processing chamber and the second processing chamber and having a transfer device;
Equipped with
The control unit is
(a) placing a substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film on the first substrate support of the first process chamber, the mask having an opening exposing the recess;
(b) forming a carbon-containing film on sidewalls of the silicon-containing film defining the recess in the first processing chamber;
(c) transferring the substrate from the first processing chamber to the second processing chamber via a transfer chamber and placing the substrate on the second substrate support;
(d) etching a bottom of the recess on which the carbon-containing film is formed in the second processing chamber; and
Including,
The process (d) is
(d1) exposing the substrate to plasma generated from a fourth process gas containing hydrogen fluoride gas;
(d2) exposing the substrate to a plasma generated from a fifth process gas including a fluorocarbon gas and/or a hydrofluorocarbon gas;
(d3) exposing the substrate to a plasma generated from a sixth process gas comprising a hydrogen-containing gas;
The plasma processing system performs a process that repeats a cycle including:

(Appendix 20)
A chamber;
a substrate support disposed within the chamber;
A plasma generating unit;
A control unit;
Equipped with
The control unit is
(a) placing a substrate, the substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film, the mask having an opening exposing the recess, on the substrate support;
(b) forming a carbon-containing film on a sidewall of the silicon-containing film defining the recess in the chamber;
(c) etching the bottom of the recess on which the carbon-containing film is formed, using plasma generated from a process gas containing hydrogen fluoride gas in the chamber;
The plasma processing apparatus performs the above steps.

(Appendix 21)
1. An etching method comprising the steps of:
(a) placing a substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film on a first substrate support in a first processing chamber, the mask having an opening exposing the recess;
(b) forming a carbon-containing film on sidewalls of the silicon-containing film defining the recess in the first processing chamber;
(c) transferring the substrate from the first processing chamber to a second processing chamber via a transfer chamber and placing the substrate on a second substrate support in the second processing chamber;
(d) etching a bottom of the recess on which the carbon-containing film is formed, using plasma generated from a process gas containing hydrogen fluoride gas in the second process chamber;
An etching method comprising:

The above embodiments are described for illustrative purposes 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.

1: Plasma processing device, 2: Control unit, 10: Plasma processing chamber, 10s: Plasma processing space, 11: Substrate support unit, 12: Plasma generation unit, 20: Gas supply unit, 30: Power source, OP: Opening, PS: Substrate processing system, RC: Recess, SF: Silicon-containing film

Claims (21)

1. A plasma processing system comprising:
a first processing chamber having a first substrate support;
a second process chamber having a second substrate support, the second process chamber being different from the first process chamber;
a transfer chamber connected to the first processing chamber and the second processing chamber and having a transfer device;
A control unit;
Equipped with
The control unit is
(a) placing a substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film on the first substrate support of the first process chamber, the mask having an opening exposing the recess;
(b) forming a carbon-containing film on sidewalls of the silicon-containing film defining the recess in the first processing chamber;
(c) transferring the substrate from the first processing chamber to the second processing chamber via a transfer chamber and placing the substrate on the second substrate support;
(d) etching the bottom of the recess on which the carbon-containing film is formed, using plasma generated from a first process gas containing hydrogen fluoride gas in the second process chamber;
A plasma processing system. The plasma processing system of claim 1, wherein the control unit executes a process that repeats a cycle including (a), (b), (c), and (d) multiple times. The plasma processing system of claim 1, wherein the control unit controls the pressure in the transfer chamber so that the pressure in the transfer chamber is lower than the pressure in the first processing chamber and the pressure in the second processing chamber at least in (c). The plasma processing system of claim 1, wherein the control unit performs a process to prepare the substrate including a silicon-containing film having the recess by forming the recess in the silicon-containing film by etching in the second processing chamber or in a third chamber different from the second chamber using plasma generated from a second processing gas containing a fluorine-containing gas, prior to (a). The plasma processing system of claim 1, wherein the temperature of the first substrate support in the process (b) is higher than the temperature of the second substrate support in the process (c). The plasma processing system of claim 1, wherein the control unit performs a process of forming the carbon-containing film using a third process gas containing a carbon-containing gas in (b). The plasma processing system of claim 6, wherein the carbon-containing gas is a hydrocarbon gas. The plasma processing system of claim 6, wherein the third process gas includes a nitrogen-containing gas. The control unit, in (b),
(b11) supplying a precursor gas to the substrate and allowing the precursor gas to be adsorbed on the side wall;
(b12) supplying a reactive gas to the substrate to form the carbon-containing film by a reaction between the precursor gas and the reactive gas;
10. The plasma processing system of claim 1, further comprising: The (b) is
(b1) supplying a first deposition gas containing a first organic compound into the first processing chamber;
(b2) supplying a second deposition gas into the first process chamber, the second deposition gas including a second organic compound different from the first organic compound;
The plasma processing system of claim 1 , comprising: The plasma processing system of claim 10, wherein (b2) forms the carbon-containing film by a reaction including polymerization of the first organic compound and the second organic compound. The plasma processing system of claim 1, wherein (d) further includes a process for enlarging a dimension of the portion of the recess that is etched in (d). The plasma processing system of claim 1, wherein the first process gas further comprises a phosphorus-containing gas. The plasma processing system of claim 1, wherein the first process gas further comprises at least one gas selected from the group consisting of a carbon-containing gas, a halogen-containing gas, and a metal-containing gas. The plasma processing system of claim 14, wherein the process (d) is performed with the temperature of the second substrate support being equal to or lower than 0°C. the first processing chamber is coupled to an inductively coupled plasma generator;
the second processing chamber is coupled to a capacitively coupled plasma generating unit;
2. The plasma processing system of claim 1, wherein the control unit performs a process of forming the carbon-containing film by generating plasma using an inductively coupled plasma generating unit in the process (b), and performs a process of etching the silicon-containing film by generating plasma using the capacitively coupled plasma generating unit in the process (d). The plasma processing system according to any one of claims 1 to 16, wherein the silicon-containing film is a silicon oxide film, a silicon nitride film, a polycrystalline silicon film, or a laminated film containing two or more of these. The plasma processing system of any one of claims 1 to 16, wherein the mask is a carbon-containing film or a metal-containing film. 1. A plasma processing system comprising:
a first processing chamber having a first substrate support;
a second processing chamber having a second substrate support, the second processing chamber being different from the first processing chamber;
a transfer chamber control unit connected to the first processing chamber and the second processing chamber and having a transfer device;
Equipped with
The control unit is
(a) placing a substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film on the first substrate support of the first process chamber, the mask having an opening exposing the recess;
(b) forming a carbon-containing film on sidewalls of the silicon-containing film defining the recess in the first processing chamber;
(c) transferring the substrate from the first processing chamber to the second processing chamber via a transfer chamber and placing the substrate on the second substrate support;
(d) etching a bottom of the recess on which the carbon-containing film is formed in the second processing chamber; and
Including,
The process (d) is
(d1) exposing the substrate to plasma generated from a fourth process gas containing hydrogen fluoride gas;
(d2) exposing the substrate to a plasma generated from a fifth process gas including a fluorocarbon gas and/or a hydrofluorocarbon gas;
(d3) exposing the substrate to a plasma generated from a sixth process gas comprising a hydrogen-containing gas;
The plasma processing system performs a process that repeats a cycle including: A chamber;
a substrate support disposed within the chamber;
A plasma generating unit;
A control unit;
Equipped with
The control unit is
(a) placing a substrate, the substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film, the mask having an opening exposing the recess, on the substrate support;
(b) forming a carbon-containing film on a sidewall of the silicon-containing film defining the recess in the chamber;
(c) etching the bottom of the recess on which the carbon-containing film is formed, using plasma generated from a process gas containing hydrogen fluoride gas in the chamber;
The plasma processing apparatus performs the above steps. 1. An etching method comprising the steps of:
(a) placing a substrate comprising a silicon-containing film having a recess and a mask on the silicon-containing film on a first substrate support in a first processing chamber, the mask having an opening exposing the recess;
(b) forming a carbon-containing film on sidewalls of the silicon-containing film defining the recess in the first processing chamber;
(c) transferring the substrate from the first processing chamber to a second processing chamber via a transfer chamber and placing the substrate on a second substrate support in the second processing chamber;
(d) etching a bottom of the recess on which the carbon-containing film is formed, using plasma generated from a process gas containing hydrogen fluoride gas in the second process chamber;
An etching method comprising:

Images