Plasma processing method

Abstract

The present invention provides a technology for modifying at least a part of a metal-containing film. A plasma processing method according to the present disclosure is executed in a plasma processing device that has a plasma processing chamber. The plasma processing method includes: (a) a step for preparing a substrate which has an etching object film and a metal-containing film on the etching object film in the plasma processing chamber, the metal-containing film having an opening pattern that includes an opening from which the etching object film is exposed; (b) a step for generating a first plasma from a processing gas which contains an oxygen-containing gas or a hydrogen-containing gas in the plasma processing chamber so as to modify at least a part of the metal-containing film; and (c) a step for etching the etching object film by generating a second plasma from a processing gas which contains a halogen-containing gas in the plasma processing chamber, wherein the etching object film is etched in the opening using the modified metal-containing film as a mask.

Description

Plasma treatment method

[0001] An exemplary embodiment of the present disclosure relates to a plasma processing method.

[0002] Conventionally, there is a technique for etching a film to be etched using a metal-containing film as a mask. For example, a CF ４ The SiO film to be etched is etched by plasma of a processing gas containing ２ There is a technique for etching the film.

[0003] Japanese Patent Application Laid-Open No. 2003-282539

[0004] The present disclosure provides techniques for modifying at least a portion of a metal-containing film.

[0005] In one exemplary embodiment of the present disclosure, there is provided a plasma processing method performed in a plasma processing apparatus having a plasma processing chamber, the plasma processing method including: (a) providing a substrate having a film to be etched and a metal-containing film on the film to be etched in the plasma processing chamber, the metal-containing film having an opening pattern including openings exposing the film to be etched; (b) generating a first plasma in the plasma processing chamber from a process gas including an oxygen-containing gas or a hydrogen-containing gas to modify at least a portion of the metal-containing film; and (c) generating a second plasma in the plasma processing chamber from a process gas including a halogen-containing gas to etch the film to be etched, the film to be etched being etched in the openings using the modified metal-containing film as a mask.

[0006] According to one exemplary embodiment of the present disclosure, a technique can be provided for modifying at least a portion of a metal-containing film.

[0007] FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system. FIG. 2 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. FIG. 3 is a flowchart showing an example of a plasma processing method according to an exemplary embodiment. FIG. 4 is a diagram showing an example of the cross-sectional structure of a substrate W provided in process ST1. FIG. 5 is a diagram showing an example of the cross-sectional structure of a substrate W in which a part of a metal-containing film MF has been modified in process ST2. FIG. 6 is a diagram showing an example of the cross-sectional structure of a substrate W after an etching target film EF has been etched in process ST3.

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

[0009] In one exemplary embodiment, a plasma processing method is provided in a plasma processing apparatus having a plasma processing chamber, the plasma processing method including: (a) providing a substrate in the plasma processing chamber, the substrate having a film to be etched and a metal-containing film on the film to be etched, the metal-containing film having an opening pattern including openings exposing the film to be etched; (b) generating a first plasma in the plasma processing chamber from a process gas including an oxygen-containing gas or a hydrogen-containing gas to modify at least a portion of the metal-containing film; and (c) generating a second plasma in the plasma processing chamber from a process gas including a halogen-containing gas to etch the film to be etched in the openings using the modified metal-containing film as a mask.

[0010] In one exemplary embodiment, the metal-containing film comprises at least one selected from the group consisting of organometallic complexes, organometallic compound salts, and metal alkoxides.

[0011] In one exemplary embodiment, the metal-containing film comprises at least one selected from the group consisting of a magnesium complex, an organic acid metal salt, and a magnesium alkoxide.

[0012] In one exemplary embodiment, the metal-containing film comprises at least one metal selected from the group consisting of alkaline earth metals and transition metals.

[0013] In one exemplary embodiment, the metal-containing film comprises magnesium.

[0014] In one exemplary embodiment, the metal-containing film comprises magnesium acrylate or magnesium gluconate.

[0015] In one exemplary embodiment, the oxygen-containing gas comprises at least one selected from the group consisting of oxygen, carbon dioxide, carbon monoxide, and ozone.

[0016] In one exemplary embodiment, the hydrogen-containing gas is a mixture of hydrogen and water vapor (H ２ O).

[0017] In one exemplary embodiment, the halogen-containing gas comprises a fluorine-containing gas.

[0018] In one exemplary embodiment, the halogen-containing gas comprises at least one selected from the group consisting of fluorocarbons, hydrofluorocarbons, nitrogen trifluoride, sulfur hexafluoride, fluorine, hydrogen fluoride, and tungsten hexafluoride.

[0019] In one exemplary embodiment, the film to be etched is a tungsten-containing film.

[0020] In one exemplary embodiment, the halogen-containing gas is a chlorine-containing gas.

[0021] In one exemplary embodiment, the film to be etched is an aluminum-containing film or a chromium-containing film.

[0022] In one exemplary embodiment, in step (b), the metal-containing film is modified from a surface of the metal-containing film to a first depth, and in step (c), the metal-containing film is etched from a surface of the metal-containing film to a second depth, the first depth being greater than the second depth.

[0023] In one exemplary embodiment, the method further comprises repeating steps (b) and (c).

[0024] In one exemplary embodiment, modifying at least a portion of the metal-containing film in step (b) includes forming an oxide of the metal contained in the metal-containing film on at least the surface of the metal-containing film.

[0025] In one exemplary embodiment, modifying at least a portion of the metal-containing film in step (b) includes reducing a surface roughness of the metal-containing film.

[0026] In one exemplary embodiment, the film to be etched includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film other than the metal-containing film.

[0027] In one exemplary embodiment, the silicon-containing film comprises at least one selected from the group consisting of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon oxycarbide film, and a polysilicon film.

[0028] In one exemplary embodiment, the other metal-containing film comprises at least one selected from the group consisting of a tungsten-containing film, a chromium-containing film, a nickel-containing film, and an aluminum-containing film.

[0029] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are designated by the same reference numerals, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships, such as up, down, left, and right, will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0030] FIG. 1 is a diagram illustrating an exemplary configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0031] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0032] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

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

[0034] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. 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.

[0035] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

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

[0037] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0038] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0039] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process 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 showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0040] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 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.

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

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

[0043] The second RF generator 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 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 lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

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

[0045] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating the 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 either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0046] 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 regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0047] <Example of Plasma Processing Method> Figure 3 is a flowchart showing an example of a plasma processing method (hereinafter also referred to as "this method") according to one illustrative embodiment. As shown in Figure 3, this method includes a step (ST1) of preparing a substrate W, a step (ST2) of modifying a metal-containing film MF, and a step (ST3) of etching an etching target film EF. The processing in each step may be performed by the plasma processing apparatus 1 described above. Below, an example will be described in which the control unit 2 controls each part of a capacitively coupled plasma processing apparatus 1 (see Figures 1 and 2) to perform this method on a substrate W.

[0048] (Step ST1: Preparation of Substrate) In step ST1, a substrate W is prepared. The substrate W may be provided in the plasma processing space 10s of the plasma processing apparatus 1. The substrate W is carried into the chamber 10 by a transport arm and placed on the central region 111a of the substrate support part 11. The substrate W may be attracted and held on the substrate support part 11 by an electrostatic chuck 1111.

[0049] 4 is a diagram showing an example of the cross-sectional structure of a substrate W provided in process ST1. The substrate W has an etching target film EF and a metal-containing film MF. The substrate W may further include an undercoat film UF. Some or all of the components included in the substrate W may be formed in the plasma processing apparatus 1. Alternatively, some or all of the components included in the substrate W may be formed outside the plasma processing apparatus 1. The substrate W may be used in the manufacture of a semiconductor device. The semiconductor device may be, for example, a semiconductor memory device such as a DRAM or a 3D-NAND flash memory.

[0050] In one embodiment, the undercoat film UF is a silicon wafer, an organic film, a dielectric film, a metal film, a semiconductor film, or a laminate film thereof formed on a silicon wafer. In one embodiment, the undercoat film UF includes at least one film selected from the group consisting of a silicon-containing film, a carbon-containing film, and a metal-containing film.

[0051] The etching target film EF is a film to be etched in step ST3, which will be described later. The etching target film EF may be composed of one type of film among the films exemplified below, or may be composed of two or more types of films stacked together.

[0052] In one embodiment, the film to be etched EF may be a carbon-containing film. For example, the carbon-containing film may be an amorphous carbon film or a spin-on carbon (SOC) film.

[0053] In one embodiment, the etching target film EF may be a silicon-containing film. For example, the silicon-containing film may be a silicon oxide film, a silicon nitride film, a silicon oxynitride film (SiON), a carbon-doped silicon oxide film (SiOC), a silicon carbonitride film (SiCN), a silicon oxycarbonitride film (SiOCN), a silicon-containing antireflective coating (SiARC), or a polysilicon film.

[0054] In one embodiment, the etching film EF may be a metal-containing film that is different from the metal-containing film MF. As an example, the metal-containing film may be a tungsten-containing film, a chromium-containing film, a nickel-containing film, or an aluminum-containing film.

[0055] The metal-containing film MF is a film that functions as a mask when etching the etching target film EF. In one embodiment, the metal-containing film MF may have an opening pattern including at least one opening OP. In one embodiment, the metal-containing film MF may include a top surface TS and a side surface SS. As shown in FIG. 4 , the side surface SS of the metal-containing film MF defines at least one opening OP on the etching target film EF. The opening OP is a space above the etching target film EF and is surrounded by the side surface SS of the metal-containing film MF. That is, the top surface of the etching target film EF may include an area covered by the metal-containing film MF and an area exposed at the bottom of the opening OP.

[0056] The openings OP may have any shape when viewed from above the substrate W, i.e., when the substrate W is viewed from top to bottom in FIG. 5 . The shape may be, for example, a circle, an ellipse, a rectangle, a line, or a combination of one or more of these. The metal-containing film MF may have multiple side surfaces SS, and the multiple side surfaces SS may 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. Alternatively, the multiple openings OP may each have a hole shape and form an array pattern.

[0057] The metal-containing film MF may be a single-layer mask consisting of one type of metal-containing film, or may be a multi-layer mask consisting of two or more types of metal-containing films. For example, the metal-containing film MF may be a film containing an organometallic complex, an organometallic compound salt, and / or a metal alkoxide. For example, the metal-containing film MF may be a film containing a magnesium complex, an organic acid metal salt, and / or a magnesium alkoxide. For example, the metal-containing film MF may be a film containing an alkaline earth metal and / or a transition metal. For example, the metal-containing film MF may contain magnesium. When the metal-containing film MF contains magnesium, the metal-containing film MF may be a film containing magnesium acrylate or magnesium gluconate.

[0058] (Step ST2: Modification of Metal-Containing Film) In step ST2, at least a portion of the metal-containing film MF is modified. Modifying a portion of the metal-containing film MF can be modifying at least the vicinity of the surface of the metal-containing film MF. The vicinity of the surface of the metal-containing film MF can include the vicinity of the surface of the top surface TS and / or the side surface SS of the metal-containing film MF.

[0059] In one embodiment, modifying the metal-containing film MF can be changing a portion of the compound contained in the metal-containing film MF. As an example, changing a portion of the compound contained in the metal-containing film MF can be forming an oxide of the metal contained in the metal-containing film MF in the metal-containing film MF.

[0060] In one embodiment, modifying the metal-containing film MF can be to reduce the surface roughness of the metal-containing film MF. Also, in one embodiment, modifying the metal-containing film MF can be to reduce the porosity of the metal-containing film MF.

[0061] In step ST2, a processing gas is supplied to the plasma processing space 10s in which the substrate W is placed, and an RF signal is supplied to the upper electrode and / or the lower electrode. This generates plasma from the processing gas, which can modify the metal-containing film MF. In one embodiment, the processing gas can include an oxygen-containing gas and / or a hydrogen-containing gas. For example, the oxygen-containing gas can be oxygen, carbon dioxide, carbon monoxide, and / or ozone. For example, the hydrogen-containing gas can be hydrogen and / or water vapor.

[0062] 5 is a diagram showing an example of the cross-sectional structure of a substrate W in which a portion of a metal-containing film MF has been modified in step ST2. As shown in FIG. 5, a portion or all of the metal-containing film MF is modified in step ST2, and the metal-containing film MF may include a modified portion MP.

[0063] As an example, when the metal-containing film MF is a magnesium-containing film, plasma may be generated from a processing gas containing an oxygen-containing gas in step ST2 to modify the magnesium-containing film. In this case, magnesium oxide is formed as modified portions MP in the magnesium-containing film, and at least the surface of the magnesium-containing film may be modified. As an example, the magnesium-containing film may be magnesium acrylate and / or magnesium gluconate. The oxygen-containing gas may be oxygen (O ２ ) can be.

[0064] As an example, when the metal-containing film MF is a zinc-containing film, in step ST2, plasma may be generated from a processing gas containing an oxygen-containing gas to modify the zinc-containing film. In this case, zinc oxide is formed as modified portions MP in the zinc-containing film, and at least the surface of the zinc-containing film may be modified. As an example, the zinc-containing film may be zinc acrylate. The oxygen-containing gas may be oxygen (O ２ ) can be.

[0065] (Step ST3: Etching of Etching Target Film) In step ST3, the etching target film EF is etched. In one embodiment, a processing gas is supplied to the plasma processing space 10s in which the substrate W is placed, and an RF signal is supplied to the upper electrode and / or the lower electrode. This generates plasma from the processing gas, and the etching target film EF can be etched. The processing gas can be a halogen-containing gas.

[0066] In one embodiment, the halogen-containing gas can be a fluorine-containing gas. By way of example, the halogen-containing gas can be a fluorocarbon, a hydrofluorocarbon, nitrogen trifluoride, sulfur hexafluoride, fluorine, hydrogen fluoride, and / or tungsten hexafluoride. Also, in one embodiment, the halogen-containing gas can be a chlorine-containing gas. By way of example, the chlorine-containing gas can be chlorine.

[0067] For example, if the film EF to be etched is a silicon-containing film or a tungsten-containing film, the processing gas may include a fluorine-containing gas. For example, if the film EF to be etched is an aluminum-containing film or a chromium-containing film, the processing gas may include a chlorine-containing gas.

[0068] 6 is a diagram showing an example of the cross-sectional structure of the substrate W after the etching target film EF is etched in step ST3. As shown in FIG. 6, recesses are formed in the etching target film EF by step ST3. Also, as shown in FIG. 6, a portion of the metal-containing film MF may also be etched in step ST3. In one embodiment, a portion of the modified portion MP may be etched, or the entire modified portion MP may be etched.

[0069] In one embodiment, in step ST2, the modified portion MP may be formed to a predetermined depth from the surface of the metal-containing film MF. Furthermore, in step ST3, the etching target film EF may be etched so that a portion of the modified portion MP remains. That is, the depth to which the metal-containing film MF is modified in step ST2 may be deeper than the depth to which the metal-containing film MF or the modified portion MP is etched in step ST3.

[0070] In one embodiment, steps ST2 and ST3 may be performed consecutively in the same plasma processing chamber. Also, in one embodiment, steps ST2 and ST3 may be performed repeatedly.

[0071] According to one exemplary embodiment of the present disclosure, at least a portion of the metal-containing film MF is modified. This can increase the etching resistance of the metal-containing film MF when etching the etching target film EF. That is, according to one exemplary embodiment of the present disclosure, when etching the etching target film EF using the metal-containing film MF as a mask, the etching selectivity can be improved.

[0072] The present disclosure may include, for example, the following configurations.

[0073] (Supplementary Note 1) A plasma processing method performed in a plasma processing apparatus having a plasma processing chamber, the plasma processing method comprising: (a) preparing, in the plasma processing chamber, a substrate having a film to be etched and a metal-containing film on the film to be etched, the metal-containing film having an opening pattern including openings exposing the film to be etched; (b) generating, in the plasma processing chamber, a first plasma from a processing gas containing an oxygen-containing gas or a hydrogen-containing gas to modify at least a portion of the metal-containing film; and (c) generating, in the plasma processing chamber, a second plasma from a processing gas containing a halogen-containing gas to etch the film to be etched, the film to be etched being etched in the openings using the modified metal-containing film as a mask.

[0074] (Supplementary Note 2) The plasma processing method according to Supplementary Note 1, wherein the metal-containing film contains at least one selected from the group consisting of an organometallic complex, an organometallic compound salt, and a metal alkoxide.

[0075] (Supplementary Note 3) The plasma processing method according to Supplementary Note 2, wherein the metal-containing film contains at least one selected from the group consisting of a magnesium complex, an organic acid metal salt, and a magnesium alkoxide.

[0076] (Supplementary Note 4) The plasma processing method according to Supplementary Note 1, wherein the metal-containing film contains at least one metal selected from the group consisting of alkaline earth metals and transition metals.

[0077] (Supplementary Note 5) The plasma processing method according to Supplementary Note 1, wherein the metal-containing film contains magnesium.

[0078] (Supplementary Note 6) The plasma processing method according to Supplementary Note 5, wherein the metal-containing film contains magnesium acrylate or magnesium gluconate.

[0079] (Supplementary Note 7) The plasma processing method according to any one of Supplementary Notes 1 to 6, wherein the oxygen-containing gas contains at least one selected from the group consisting of oxygen, carbon dioxide, carbon monoxide, and ozone.

[0080] (Supplementary Note 8) The plasma processing method according to any one of Supplementary Notes 1 to 6, wherein the hydrogen-containing gas contains at least one selected from the group consisting of hydrogen and water vapor.

[0081] (Supplementary Note 9) The plasma processing method according to any one of Supplementary Notes 1 to 8, wherein the halogen-containing gas includes a fluorine-containing gas.

[0082] (Supplementary Note 10) The plasma processing method according to Supplementary Note 9, wherein the halogen-containing gas includes at least one gas selected from the group consisting of fluorocarbon, hydrofluorocarbon, nitrogen trifluoride, sulfur hexafluoride, fluorine, hydrogen fluoride, and tungsten hexafluoride.

[0083] (Supplementary Note 11) The plasma processing method according to Supplementary Note 9, wherein the etching target film is a tungsten-containing film.

[0084] (Supplementary Note 12) The plasma processing method according to any one of Supplementary Notes 1 to 8, wherein the halogen-containing gas is a chlorine-containing gas.

[0085] (Supplementary Note 13) The plasma processing method according to Supplementary Note 12, wherein the etching target film is an aluminum-containing film or a chromium-containing film.

[0086] (Appendix 14) The plasma processing method according to any one of Appendices 1 to 13, wherein in the step (b), the metal-containing film is modified from a surface of the metal-containing film to a first depth, and in the step (c), the metal-containing film is etched from a surface of the metal-containing film to a second depth, the first depth being greater than the second depth.

[0087] (Supplementary Note 15) The plasma processing method according to any one of Supplementary Notes 1 to 14, further comprising the step of repeating the steps (b) and (c).

[0088] (Supplementary Note 16) The plasma processing method according to any one of Supplementary Notes 1 to 15, wherein in the step (b), modifying at least a portion of the metal-containing film includes forming an oxide of the metal contained in the metal-containing film on at least a surface of the metal-containing film.

[0089] (Supplementary Note 17) The plasma processing method according to any one of Supplementary Notes 1 to 16, wherein in the step (b), modifying at least a portion of the metal-containing film includes reducing a surface roughness of the metal-containing film.

[0090] (Supplementary Note 18) The plasma processing method according to any one of Supplementary Notes 1 to 16, wherein in the step (b), modifying at least a portion of the metal-containing film includes reducing the porosity of the metal-containing film.

[0091] (Supplementary Note 19) The plasma processing method according to any one of Supplementary Notes 1 to 18, wherein the etching target film includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film different from the metal-containing film.

[0092] (Supplementary Note 20) The plasma processing method according to Supplementary Note 19, wherein the silicon-containing film includes at least one selected from the group consisting of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon oxycarbide film, a silicon carbonitride film, and a polysilicon film.

[0093] (Supplementary Note 21) The plasma processing method according to Supplementary Note 19, wherein the other metal-containing film includes at least one selected from the group consisting of a tungsten-containing film, a chromium-containing film, a nickel-containing film, and an aluminum-containing film.

[0094] (Supplementary Note 22) A plasma processing apparatus having a plasma processing chamber and a control unit, wherein the control unit performs the following processes: (a) a process of preparing, in the plasma processing chamber, a substrate having a film to be etched and a metal-containing film on the film to be etched, wherein the metal-containing film has an opening pattern including openings that expose the film to be etched; (b) a process of generating, in the plasma processing chamber, a first plasma from a process gas containing an oxygen-containing gas or a hydrogen-containing gas to modify at least a portion of the metal-containing film; and (c) a process of generating, in the plasma processing chamber, a second plasma from a process gas containing a halogen-containing gas to etch the film to be etched, wherein the film to be etched is etched in the openings using the modified metal-containing film as a mask.

[0095] Various modifications can be made to the above exemplary embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments within the scope of ordinary creativity of a person skilled in the art. Also, some components in one embodiment can be replaced with corresponding components in other embodiments.

[0096] 1: plasma processing apparatus, 10: plasma processing chamber, EF: film to be etched, MF: metal-containing film, OP: opening, W: substrate

Claims

1. A plasma processing method carried out in a plasma processing apparatus having a plasma processing chamber, the method comprising: (a) preparing a substrate having a film to be etched and a metal-containing film on the film to be etched in the plasma processing chamber, the metal-containing film having an opening pattern including openings exposing the film to be etched; (b) generating a first plasma in the plasma processing chamber from a process gas containing an oxygen-containing gas or a hydrogen-containing gas to modify at least a portion of the metal-containing film; and (c) generating a second plasma in the plasma processing chamber from a process gas containing a halogen-containing gas to etch the film to be etched in the openings using the modified metal-containing film as a mask.

2. The plasma processing method according to claim 1, wherein the metal-containing film contains at least one selected from the group consisting of organometallic complexes, organometallic compound salts, and metal alkoxides.

3. The plasma processing method according to claim 2, wherein the metal-containing film contains at least one selected from the group consisting of magnesium complexes, organic acid metal salts, and magnesium alkoxides.

4. The plasma processing method according to claim 1, wherein the metal-containing film contains at least one metal selected from the group consisting of alkaline earth metals and transition metals.

5. The plasma processing method of claim 1, wherein the metal-containing film contains magnesium.

6. The plasma processing method of claim 5, wherein the metal-containing film comprises magnesium acrylate or magnesium gluconate.

7. The plasma processing method according to claim 1, wherein the oxygen-containing gas contains at least one gas selected from the group consisting of oxygen, carbon dioxide, carbon monoxide, and ozone.

8. The plasma processing method according to claim 1, wherein the hydrogen-containing gas contains at least one selected from the group consisting of hydrogen and water.

9. The plasma processing method of claim 1, wherein the halogen-containing gas includes a fluorine-containing gas.

10. The plasma processing method according to claim 9, wherein the halogen-containing gas includes at least one selected from the group consisting of fluorocarbons, hydrofluorocarbons, nitrogen trifluoride, sulfur hexafluoride, fluorine, hydrogen fluoride, and tungsten hexafluoride.

11. The plasma processing method according to claim 9, wherein the film to be etched is a tungsten-containing film.

12. The plasma processing method according to claim 1, wherein the halogen-containing gas is a chlorine-containing gas.

13. The plasma processing method according to claim 12, wherein the film to be etched is an aluminum-containing film or a chromium-containing film.

14. The plasma processing method according to any one of claims 1 to 13, wherein in step (b), the metal-containing film is modified from the surface of the metal-containing film to a first depth, and in step (c), the metal-containing film is etched from the surface of the metal-containing film to a second depth, the first depth being deeper than the second depth.

15. The plasma processing method according to any one of claims 1 to 13, further comprising the step of repeating steps (b) and (c).

16. A plasma processing method according to any one of claims 1 to 13, wherein in step (b), modifying at least a portion of the metal-containing film includes forming an oxide of the metal contained in the metal-containing film on at least the surface of the metal-containing film.

17. The plasma processing method according to any one of claims 1 to 13, wherein in step (b), modifying at least a portion of the metal-containing film includes reducing the surface roughness of the metal-containing film.

18. The plasma processing method according to claim 1, wherein the film to be etched includes at least one selected from the group consisting of a carbon-containing film, a silicon-containing film, and a metal-containing film different from the metal-containing film.

19. The plasma processing method according to claim 18, wherein the silicon-containing film includes at least one selected from the group consisting of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon oxycarbide film, a silicon carbonitride film, and a polysilicon film.

20. The plasma processing method according to claim 18, wherein the other metal-containing film includes at least one selected from the group consisting of a tungsten-containing film, a chromium-containing film, a nickel-containing film, and an aluminum-containing film.

Images