Plasma processing method and plasma processing apparatus

Abstract

The present invention provides a plasma processing method with which it is possible to reduce the occurrence of bowing during etching. A plasma processing method according to the present disclosure is executed in a plasma processing apparatus that has a chamber, the plasma processing method including: a preparation step for preparing a substrate, which has a first film and a second film that is provided on the first film, in the chamber, the second film containing an organic-inorganic hybrid material, the second film having an opening pattern, and the first film being exposed in at least one opening which is defined by the opening pattern; a step for supplying a processing gas into the chamber; a step for generating plasma from the processing gas; and an etching step for etching the first film by means of the plasma, using the second film as a mask. The etching step includes: (a) a step for forming a side wall on the first film by etching the first film using the second film as a mask, wherein the first film is etched in at least one opening that is defined by the opening pattern, and the side wall defines a recessed part in the first film; (b) a step for scattering some of the organic-inorganic hybrid material from the second film by means of the plasma; (c) a step for forming a protective film on the side wall, wherein the protective film is formed by adhering the scattered organic-inorganic hybrid material to the side wall; and (d) a step for further etching the first film in the opening using the second film as a mask.

Description

Plasma processing method and plasma processing apparatus

[0001] SUMMARY OF THE INVENTION Exemplary embodiments of the present disclosure relate to a plasma processing method and a plasma processing apparatus.

[0002] A technique for precisely anisotropically dry etching an organic low dielectric constant film using an inorganic hard mask is described in Japanese Patent Application Laid-Open No. 2003-222999.

[0003] Japanese Patent Application Laid-Open No. 2000-91308

[0004] The present disclosure provides a plasma processing method and a plasma processing apparatus capable of reducing bowing that occurs during etching.

[0005] In one exemplary embodiment of the present disclosure, there is provided a plasma processing method performed in a plasma processing apparatus having a chamber, the plasma processing method including: a preparation step of preparing a substrate in the chamber, the substrate having a first film and a second film provided on the first film, the second film including an organic-inorganic hybrid material, the second film having an opening pattern, the first film being exposed in at least one opening defined by the opening pattern; a preparation step of supplying a process gas into the chamber; a generation step of generating plasma from the process gas; and an etching step of etching the first film with the plasma using the second film as a mask, the etching step including: (a) etching the first film with the second film as a mask; The method includes: (b) etching the first film to form a sidewall in the first film, wherein the first film is etched in at least one opening defined by the opening pattern, and the sidewall defines a recess in the first film; (b) scattering a portion of the organic-inorganic hybrid material from the second film by the plasma; (c) forming a protective film on the sidewall, wherein the scattered organic-inorganic hybrid material adheres to the sidewall; and (d) further etching the first film in the opening using the second film as a mask.

[0006] According to one exemplary embodiment of the present disclosure, it is possible to provide a plasma processing method and a plasma processing apparatus capable of reducing bowing that occurs during etching.

[0007] FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system. FIG. 1 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. FIG. 2 is a diagram showing an example of the cross-sectional structure of a substrate W. FIG. 3 is a flowchart showing an example of the present processing method. FIG. 4 is a diagram showing an example of the cross-sectional structure of a substrate W in the present processing method. FIG. 5 is a diagram showing an example of the cross-sectional structure of a substrate W in the present processing method. FIG. 6 is a diagram showing an example of the cross-sectional structure of a substrate W in the present processing method.

[0008]

[0013] In one exemplary embodiment, a plasma processing method is provided that is performed in a plasma processing apparatus having a chamber. The plasma processing method includes: a preparation step of preparing a substrate having a first film and a second film provided on the first film in the chamber, the second film including an organic-inorganic hybrid material, the second film having an opening pattern, and the first film being exposed in at least one opening defined by the opening pattern; a preparation step of supplying a process gas into the chamber; a step of generating plasma from the process gas; and an etching step of etching the first film with the plasma using the second film as a mask, the etching step including: (a) removing the second film from the mask; (b) etching the first film using a plasma to form a sidewall in the first film, wherein the first film is etched in at least one opening defined by the opening pattern, and the sidewall defines a recess in the first film; (b) scattering a portion of the organic-inorganic hybrid material from the second film using plasma; (c) forming a protective film on the sidewall, wherein the protective film is formed by the scattered organic-inorganic hybrid material adhering to the sidewall; and (d) further etching the first film in the opening using the second film as a mask.

[0009] In one exemplary embodiment, the etching step further includes modifying at least a portion of the organic-inorganic hybrid material contained in the second film by plasma.

[0010] In one exemplary embodiment, the etching step further includes modifying at least a portion of the organic-inorganic hybrid material contained in the protective film.

[0011] In one exemplary embodiment, the processing gas includes an oxidizing gas that oxidizes the inorganic material contained in the organic-inorganic hybrid material, and in the etching process, the inorganic material contained in the organic-inorganic hybrid material is oxidized by plasma generated from the oxidizing gas, thereby modifying the organic-inorganic hybrid material.

[0012] In one exemplary embodiment, the oxidizing gas is an oxygen-containing gas.

[0013] In one exemplary embodiment, the processing gas includes a reducing gas that reduces the inorganic material contained in the organic-inorganic hybrid material, and in the etching process, the inorganic material contained in the organic-inorganic hybrid material is reduced by plasma generated from the reducing gas, thereby modifying the organic-inorganic hybrid material.

[0014] In one exemplary embodiment, the reducing gas is a hydrogen-containing gas.

[0015] In one exemplary embodiment, the processing gas includes a halogen-containing gas that halogenates the inorganic material contained in the organic-inorganic hybrid material, and in the etching process, the inorganic material contained in the organic-inorganic hybrid material is halogenated by plasma generated from an oxidizing gas, thereby modifying the organic-inorganic hybrid material.

[0016] In one exemplary embodiment, the organic-inorganic hybrid material includes a metal, and the etching process modifies the organic-inorganic hybrid material by changing the valence of the metal's ions.

[0017] In one exemplary embodiment, the opening has a circular or rectangular shape in a plan view of the substrate.

[0018] In one exemplary embodiment, the pattern and the openings form lines and spaces in a plan view of the substrate.

[0019] In one exemplary embodiment, the second film is formed by a nanoimprint method, a self-assembly lithography method, or an inkjet method.

[0020] In one exemplary embodiment, the organic-inorganic hybrid material comprises at least one metal selected from the group consisting of Mg, Zn, Y, Ni, Ti, Fe, and Al.

[0021] In one exemplary embodiment, the etching rate of the first film relative to the etching rate of the second film in step (d) is greater than the etching rate of the first film relative to the etching rate of the second film in step (a).

[0022] In one exemplary embodiment, the organic-inorganic hybrid film comprises an organic material and an inorganic material, and the content of the organic material in the organic-inorganic hybrid film in step (d) is lower than the content of the organic material in the organic-inorganic hybrid film in step (a).

[0023] In one exemplary embodiment, a plasma processing apparatus is provided, the plasma processing apparatus including a chamber, a gas supply unit for supplying a process gas into the chamber, a plasma generation unit for generating plasma in the chamber, and a control unit, the control unit controlling: preparing a substrate in the chamber, the substrate having a first film and a second film disposed on the first film, the second film including an organic-inorganic hybrid material, the second film having an opening pattern, the first film being exposed in at least one opening defined by the opening pattern; supplying a process gas into the chamber; generating plasma from the process gas; and etching the first film with the plasma using the second film as a mask. The etching control includes: (a) etching the first film using the second film as a mask to form a sidewall in the first film, where the first film is etched in at least one opening defined by the opening pattern, and the sidewall defines a recess in the first film; (b) scattering a portion of the organic-inorganic hybrid material from the second film by plasma; (c) forming a protective film on the sidewall, where the scattered organic-inorganic hybrid material adheres to the sidewall; and (d) using the second film as a mask to further etch the first film in the opening.

[0024] 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.

[0025] <Example of Plasma Processing System> FIG. 1 is a diagram illustrating an example of the 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.

[0026] 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.

[0027] <Example of CCP Plasma Processing Apparatus> FIG. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0028] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2. 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 has at least one gas inlet for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space 10s. 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.

[0029] 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.

[0030] 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 (Radio Frequency) power supply 31 and / or a DC (Direct Current) power supply 32 (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 (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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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 one or more flow modulation devices to modulate or pulse the flow rate of the at least one process gas.

[0035] 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 process gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of a plasma generating unit configured to generate a plasma from one or more process gases in the plasma processing chamber 10. 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.

[0036] 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.

[0037] 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.

[0038] 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 bias 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.

[0039] 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 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.

[0040] 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.

[0041] <Example of Substrate W> Figure 3 is a diagram showing an example of the cross-sectional structure of a substrate W. The substrate W is an example of a substrate to which the present processing method can be applied. The substrate W has an etching film EF and an organic-inorganic hybrid film HF. The etching film EF and the organic-inorganic hybrid film HF are formed on an undercoat film UF. The organic-inorganic hybrid film HF is formed in a layer different from the etching film EF. In other words, the organic-inorganic hybrid film HF is laminated on the etching film EF. The etching film EF is an example of a first film. The organic-inorganic hybrid film HF is an example of a second film.

[0042] The base film UF may be 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 also be a silicon wafer. The base film UF may also be configured by laminating multiple films.

[0043] The etching film EF may be a carbon-containing film or a silicon-containing film. The carbon-containing film may be, for example, an amorphous carbon film or a spin-on carbon (SOC) film. The silicon-containing film may be a dielectric film containing silicon (Si). The silicon-containing film may include a silicon oxide film or a silicon nitride film.

[0044] The organic-inorganic hybrid film HF is a film containing an organic material and an inorganic material. The inorganic material may include a metal. The metal may be at least one metal selected from the group consisting of magnesium (Mg), zinc (Zn), yttrium (Y), nickel (Ni), titanium (Ti), iron (Fe), and aluminum (Al).

[0045] The organic-inorganic hybrid film HF is patterned to define at least one opening OP on the etching film EF. That is, the organic-inorganic hybrid film HF has an opening pattern for etching the etching film EF in step ST4, which will be described later. The opening pattern may be a pattern of holes, pillars, slits, lines and spaces, or the like. In plan view, the substrate W may include a region RE1, which is a region where at least one opening OP is present, and a region RE2, which is a region where the organic-inorganic hybrid film HF is present. The region RE1 is an example of a region where the etching film EF is exposed in at least one opening OP.

[0046] <Example of the Present Processing Method> Figure 4 is a flowchart showing an example of the plasma processing method (also referred to as the "present processing method") of the present disclosure. The present processing method is performed on a substrate W, for example, using the plasma processing system and plasma processing apparatus 1 shown in Figures 1 and 2. An example of performing the present processing method shown in Figure 4 will be described below with reference to the respective figures. Note that in the following example, the control unit 2 shown in Figures 1 and 2 controls each part of the plasma processing apparatus 1 shown in Figure 2 to perform the present processing method.

[0047] Figures 5A to 5F are views showing an example of the cross-sectional structure of the substrate W in this processing method. Figure 5A is a view showing an example of the cross-sectional structure of the substrate W after process ST1 has been performed. Figures 5B to 5E are views showing an example of the cross-sectional structure of the substrate W during the execution of processes ST2 to ST4. Figure 5F is a view showing an example of the cross-sectional structure of the substrate W after process ST4 has been performed. An example of this processing method will be described with reference to Figures 4 and 5.

[0048] This processing method includes a step (ST1) of determining a substrate as a reference, a step (ST2) of supplying a processing gas, a step (ST3) of generating plasma, and a step (ST4) of etching the etching film EF or the carbon-containing film CF while modifying the organic-inorganic hybrid film. Note that the order in which steps ST2 and ST3 are started or performed is not limited to this order. Furthermore, steps ST2 to ST4 may be performed in parallel or simultaneously.

[0049] <Step ST1: Preparation of Substrate> In step ST1, a substrate W is prepared in the plasma processing space 10s of the plasma processing chamber 10. In step ST1, at least the substrate W may be placed on the substrate support 11 and held by the electrostatic chuck 1111. At least a part of the process of forming each component of the substrate W may be performed in the plasma processing space 10s as part of step ST1. Alternatively, after all or a part of each component of the substrate W is formed in an apparatus or chamber external to the plasma processing apparatus 1, the substrate W may be loaded into the plasma processing space 10s and placed on the substrate support 11.

[0050] In this example, the step ST1 includes a step of forming an etching film EF (step ST1-11) and a step of forming an organic-inorganic hybrid film HF (step ST1-12).

[0051] In step ST1-11, an etching film EF is formed. The etching film EF is formed on the base film UF, for example, as shown in FIG. 5A. In this example, the etching film EF is a silicon oxide film. The etching film EF may also be a carbon-containing film. As an example, the carbon-containing film may be an amorphous carbon film.

[0052] In step ST1-12, an organic-inorganic hybrid film HF is formed on the etching film EF. In this example, the organic-inorganic hybrid film HF is a film containing an organic magnesium (Mg) compound. As an example, the organic-inorganic hybrid film HF can be formed by applying a solution containing an organic magnesium compound onto the etching film EF. The organic-inorganic hybrid film HF may be used as an etching mask in step ST44, which will be described later, either without curing or in a partially cured state.

[0053] The organic-inorganic hybrid film HF can be formed on the etching film EF by a transfer method, a nanoimprint method, a DSA (Directed Self-Assembly) method, or an inkjet method. That is, by these methods, an organic-inorganic hybrid material is attached to the region RE2 on the etching film EF to form a patterned organic-inorganic hybrid film HF on the etching film EF. As an example, when the pattern dimension of the organic-inorganic hybrid film HF is less than 1 μm, the organic-inorganic hybrid film HF can be formed by a transfer method, a nanoimprint method, or a DSA (Directed Self-Assembly) method. Furthermore, when the dimension is 1 μm or more, the organic-inorganic hybrid film HF can be formed by an inkjet method.

[0054] The region RE1 is a region where an opening OP exists on the etching film EF in a plan view of the substrate W. The region RE2 is a region where the organic-inorganic hybrid film HF is formed on the etching film EF in a plan view of the substrate W. That is, the etching film EF is exposed in the region RE1 and is covered by the organic-inorganic hybrid film HF in the region RE2.

[0055] The substrate W obtained through steps ST1-11 and ST1-12 is placed on the substrate support 11, and the substrate W is held by the electrostatic chuck 1111.

[0056] <Step ST2: Supply of Processing Gas> In step ST2, a processing gas is supplied into the plasma processing chamber 10. The processing gas is a gas used to etch the etching film EF formed on the substrate W. The processing gas may also include a gas that modifies the organic-inorganic hybrid film HF. As an example, the processing gas may include a gas that oxidizes, reduces, or halogenates the organic-inorganic hybrid film HF. As an example, the gas that reduces the inorganic material contained in the organic-inorganic hybrid film HF may be a hydrogen-containing gas. The inorganic material includes, for example, a metal.

[0057] The processing gas may contain a gas capable of etching the etching film EF or the carbon-containing film CF while modifying the organic-inorganic hybrid film HF in step ST4. As an example, when the organic-inorganic hybrid film HF is a film containing Mg and the etching film EF is a carbon-containing film, the processing gas may contain an oxygen-containing gas. In this processing method, the processing gas contains an oxygen-containing gas and a sulfur-containing gas. As an example, the oxygen-containing gas may contain oxygen (O ２ ), carbon monoxide (CO), carbon dioxide (CO ２ ) or water (H ２ The sulfur-containing gas may also include carbonyl sulfide (COS) or sulfur hexafluoride (SF ６ ) Furthermore, when the organic-inorganic hybrid film HF is a film containing Mg and the etching film EF is a film containing silicon oxide, the processing gas may contain a gas containing fluorine. Furthermore, when the organic-inorganic hybrid film HF is a film containing Mg and the etching film EF is a silicon (Si) film, the processing gas may contain a gas containing chlorine.

[0058] <Step ST3: Plasma Generation> In step ST3, plasma is generated in the plasma processing chamber 10. In this embodiment, a source RF signal is supplied to the shower head 13 or the substrate support 11 in the plasma processing apparatus 1 of FIG. 2, and plasma is generated from the processing gas in the plasma processing space 10s. In this processing method, the processing gas contains an oxygen-containing gas and a sulfur-containing gas, and when plasma is generated in step ST3, activated oxygen species are generated. The source RF signal may be a continuous wave or a pulse wave. In addition, a bias signal may be supplied to the substrate support 11 in step ST3.

[0059] <Process ST4: Modification and Etching> In process ST4, the etching film EF is etched. Process ST4 includes a process of forming a recess RC in the etching film EF (process ST41), a process of forming a protective film PF on the sidewall SS of the recess RC, a process of modifying the organic-inorganic hybrid film HF (process ST43), and a process of further etching the etching film EF in the recess RC (process ST44). Note that the order in which processes ST41 to ST43 are started, performed, or occur is not limited to this order. Furthermore, processes ST41 to ST43 may be started, performed, or occur in parallel or simultaneously.

[0060] In step ST41, a recess RC is formed in the etching film EF. As shown in FIG. 5B , the recess RC is formed by etching the etching film EF with the plasma generated in step ST3 using the organic-inorganic hybrid film HF as a mask. When the plasma etches the portion of the etching film EF exposed at the opening OP, a sidewall SS is formed in the etching film EF, and a recess RC defined by the sidewall SS is formed. If the etching film EF is a carbon-containing film, the etching film EF can be etched by the activated oxygen species generated in step ST3.

[0061] In step ST42, the organic-inorganic hybrid film HF is modified. In this processing method, active species in the plasma generated in step ST3 sputter the organic-inorganic hybrid film HF, scattering the organic-inorganic hybrid material contained in the organic-inorganic hybrid film HF. The organic-inorganic hybrid material may be a substance containing magnesium. The magnesium-containing substance may be an organic magnesium compound, magnesium oxide (MgO), other magnesium compounds, metallic magnesium, or magnesium ions.

[0062] Furthermore, the active oxygen species generated in step ST3 oxidize at least a portion of the organomagnesium compound in the organic-inorganic hybrid film HF. As an example, the active oxygen species convert the organomagnesium compound present at least on the surface of the organic-inorganic hybrid film HF into magnesium oxide (MgO). That is, the active oxygen species form a layer FP containing magnesium oxide on the surface of the organic-inorganic hybrid film HF, as shown in FIG. 5C .

[0063] In step ST43, a protective film PF is formed. Specifically, a substance containing magnesium dispersed from the organic-inorganic hybrid film HF in step ST42 adheres to the sidewall SS formed on the etching film EF in step ST41. The protective film PF may be formed from magnesium oxide dispersed from the organic-inorganic hybrid film HF in step ST42. Alternatively, the protective film PF may be formed from a substance other than magnesium oxide dispersed from the organic-inorganic hybrid film HF in step ST42. The substance may be converted to magnesium oxide by the activated oxygen species generated in step ST3.

[0064] In step ST44, the etching film EF present at the bottom of the recess RC is further etched. The plasma generated in step ST3 further etches the etching film EF at the bottom of the recess RC, further deepening the depth of the recess RC. Here, as shown in FIG. 5D, steps ST42 and ST43 may be repeatedly performed or occur while the etching film EF is further etched, thereby forming a protective film PF on the newly formed sidewall SS. Also, as shown in FIG. 5E, the sidewall SS may have a portion where the protective film PF is formed and a portion where the protective film PF is not formed. The thickness of the protective film PF may vary depending on the position or depth of the protective film PF on the sidewall SS. In step ST44, as shown in FIG. 5F, etching of the etching film EF is completed when the bottom of the recess RC reaches the base film UF.

[0065] In this processing method, the etching rate of the etching film EF relative to the etching rate of the organic-inorganic hybrid film HF may be higher in step ST44 than in step ST41. Also, the proportion of organic material contained in the organic-inorganic hybrid film HF may be higher in step ST41 than in step ST44. Also, the amount of organic-inorganic hybrid material scattered per unit time may be higher in step ST41 than in step ST44.

[0066] According to one aspect of the present processing method, the sidewall SS formed by etching the etching film EF can be protected by the protective film PF, thereby reducing bowing of the recess RC. Furthermore, according to one aspect of the present processing method, the protective film PF can be effectively formed from the early stage of etching the etching film EF. This effectively reduces bowing in the portion of the recess RC that is close to the organic-inorganic hybrid film HF.

[0067] The above embodiments have been described for illustrative purposes and various modifications may be made without departing from the scope and spirit of the present disclosure.

[0068] REFERENCE SIGNS LIST 1... plasma processing apparatus, 2... control section, 10... plasma processing chamber, 10s... plasma processing space, 11... substrate support section, 12... plasma generation section, 13... shower head, 20... gas supply section, EF... etching film, HF... organic-inorganic hybrid film, OP... opening, RC... recess, SS... side wall

Claims

1. A plasma processing method performed in a plasma processing apparatus having a chamber, comprising: a preparation step of preparing a substrate having a first film and a second film provided on the first film in the chamber, the second film including an organic-inorganic hybrid material, the second film having an opening pattern, and the first film being exposed in at least one opening defined by the opening pattern; a preparation step of supplying a processing gas into the chamber; a step of generating plasma from the processing gas; and an etching step of etching the first film with the plasma using the second film as a mask, the etching step comprising: (a) a step of etching the first film using the second film as a mask to form a sidewall in the first film, the first film being etched in at least one opening defined by the opening pattern, the sidewall defining a recess in the first film; and (b) a step of scattering a portion of the organic-inorganic hybrid material from the second film by the plasma. (c) forming a protective film on the sidewall, the protective film being formed by the scattered organic-inorganic hybrid material adhering to the sidewall; and (d) further etching the first film in the opening using the second film as a mask.

2. The plasma processing method according to claim 1, wherein the etching step further comprises a step of modifying at least a portion of the organic-inorganic hybrid material contained in the second film by the plasma.

3. The plasma processing method according to claim 1 or 2, wherein the etching step further includes a step of modifying at least a portion of the organic-inorganic hybrid material contained in the protective film.

4. The plasma processing method according to claim 2 or 3, wherein the processing gas contains an oxidizing gas that oxidizes the inorganic material contained in the organic-inorganic hybrid material, and in the etching step, the inorganic material contained in the organic-inorganic hybrid material is oxidized by plasma generated from the oxidizing gas, thereby modifying the organic-inorganic hybrid material.

5. The plasma processing method according to claim 4, wherein the oxidizing gas is an oxygen-containing gas or a sulfur-containing gas.

6. The plasma processing method according to claim 2 or 3, wherein the processing gas contains a reducing gas that reduces the inorganic material contained in the organic-inorganic hybrid material, and in the etching step, the inorganic material contained in the organic-inorganic hybrid material is reduced by plasma generated from the reducing gas, thereby modifying the organic-inorganic hybrid material.

7. The plasma processing method according to claim 6, wherein the reducing gas is a hydrogen-containing gas.

8. The plasma processing method according to claim 2 or 3, wherein the processing gas contains a halogen-containing gas that halogenates the inorganic material contained in the organic-inorganic hybrid material, and in the etching step, the inorganic material contained in the organic-inorganic hybrid material is halogenated by plasma generated from the oxidizing gas, thereby modifying the organic-inorganic hybrid material.

9. The plasma processing method according to claim 2 or 3, wherein the organic-inorganic hybrid material contains a metal, and the organic-inorganic hybrid material is modified in the etching step by changing the valence of the metal ions.

10. The plasma processing method according to any one of claims 1 to 9, wherein the opening has a circular or rectangular shape when viewed from above the substrate.

11. The plasma processing method according to any one of claims 1 to 9, wherein the pattern and the opening form a line and space when viewed from above the substrate.

12. The plasma processing method according to any one of claims 1 to 11, wherein the second film is formed by a nanoimprint method, a self-assembly lithography method, or an inkjet method.

13. The plasma processing method according to any one of claims 1 to 12, wherein the organic-inorganic hybrid material contains at least one metal selected from the group consisting of Mg, Zn, Y, Ni, Ti, Fe, and Al.

14. A plasma processing method according to any one of claims 1 to 13, wherein the etching rate of the first film relative to the etching rate of the second film in step (d) is greater than the etching rate of the first film relative to the etching rate of the second film in step (a).

15. A plasma processing method according to any one of claims 1 to 13, wherein the organic-inorganic hybrid film is composed of an organic material and an inorganic material, and the content of the organic material in the organic-inorganic hybrid film in step (d) is lower than the content of the organic material in the organic-inorganic hybrid film in step (a).

16. A plasma processing apparatus comprising: a chamber; a gas supply unit that supplies a processing gas into the chamber; a plasma generation unit that generates plasma in the chamber; and a control unit, wherein the control unit performs the following controls: (a) control of preparing, in the chamber, a substrate having a first film and a second film provided on the first film, the second film including an organic-inorganic hybrid material, the second film having an opening pattern, and the first film being exposed in at least one opening defined by the opening pattern; (b) control of supplying a processing gas into the chamber; (c) control of generating plasma from the processing gas; and (d) control of etching the first film with the plasma using the second film as a mask, wherein the etching control comprises: (a) control of etching the first film using the second film as a mask to form a sidewall in the first film, the first film being etched in at least one opening defined by the opening pattern, and the sidewall defining a recess in the first film; (b) controlling the scattering of a portion of the organic-inorganic hybrid material from the second film by the plasma; (c) controlling the formation of a protective film on the side wall, the protective film being formed by the scattered organic-inorganic hybrid material adhering to the side wall; and (d) controlling the further etching of the first film in the opening using the second film as a mask.

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