Substrate processing method and plasma processing apparatus

Abstract

The present invention provides a substrate processing method and a plasma processing apparatus, in which an organic film mask is formed.　Provided is a substrate processing method which includes: a step for preparing a substrate on which a film to be etched, an organic film that is formed on the film to be etched, and a silicon-containing film that is formed on the organic film and is provided with an opening pattern are laminated; a step for forming an opening pattern in the organic film using the silicon-containing film as a mask; and a step for removing the silicon-containing film and expanding an opening in the upper part of the organic film after the formation of the opening pattern in the organic film.

Description

Substrate processing method and plasma processing apparatus

[0001] The present disclosure relates to a substrate processing method and a plasma processing apparatus.

[0002] Patent Document 1 discloses an etching method including: a first step of etching a silicon-containing oxide film according to a pattern of a mask on the silicon-containing oxide film by using plasma generated from a first gas supplied into a processing chamber; and a second step of removing reaction products that have adhered to openings in the silicon-containing oxide film and the mask in the first step by using plasma generated from a second gas supplied into the processing chamber, wherein the second step applies high-frequency power for generating plasma and high-frequency power for generating a bias voltage to generate plasma from the second gas.

[0003] Japanese Patent Application Laid-Open No. 2019-9189

[0004] In one aspect, the present disclosure provides a substrate processing method and a plasma processing apparatus for forming an organic film mask.

[0005] In order to solve the above-described problems, according to one aspect, there is provided a substrate processing method including the steps of: preparing a substrate including a layered structure of a film to be etched, an organic film formed on the film to be etched, and a silicon-containing film formed on the organic film and having an opening pattern; forming the opening pattern in the organic film using the silicon-containing film as a mask; and, after forming the opening pattern in the organic film, removing the silicon-containing film to widen the opening in the upper part of the organic film.

[0006] According to one aspect, a substrate processing method and a plasma processing apparatus for forming an organic film mask can be provided.

[0007] 1 is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus; FIG. 2 is a flowchart illustrating an example of a substrate processing method; FIG. 3 is a schematic cross-sectional view of a substrate in each step; FIG. 4 is a schematic cross-sectional view of a substrate in each step; FIG. 5 is a schematic cross-sectional view of a substrate in each step; FIG. 6 is a schematic cross-sectional view of a substrate in each step; FIG. 7 is a schematic cross-sectional view of a substrate in a via etching process according to the present embodiment; FIG. 8 is a schematic cross-sectional view of a substrate in a via etching process according to a reference example; FIG. 9 is a schematic cross-sectional view of a substrate in a silicon-containing film removal process according to the present embodiment; FIG. 10 is a schematic cross-sectional view of a substrate in a silicon-containing film removal process according to a reference example.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] [Plasma Processing System] An example of the configuration of a plasma processing system will be described below. Fig. 1 is an example of a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus 1.

[0010] 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 into 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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 W 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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).

[0024] Next, an example of a substrate processing method will be described with reference to Fig. 2 and Fig. 3A to Fig. 3F. Fig. 2 is a flowchart showing an example of the substrate processing method. Fig. 3A to Fig. 3F are examples of schematic cross-sectional views of the substrate W in each step. Here, an example will be described in which a pattern of multiple vias (holes, openings 305) is formed in a film 300 to be etched.

[0025] In step S101, a substrate W is prepared. Here, the control unit 2 controls a transfer device (not shown) to transfer the substrate W into the plasma processing chamber 10 and place the substrate W in the central region 111a of the substrate support 11. Fig. 3A is a schematic cross-sectional view showing an example of the substrate W to be prepared. The substrate W has a film to be etched 300, an organic film 310, a silicon-containing film 320, and a photoresist film 330.

[0026] The film to be etched 300 has a first film 301 and a second film 302 formed on the first film 301 .

[0027] The first film 301 is, for example, an insulating film. The first film 301 may also be a film used as an interlayer insulating film (low-k film). The first film 301 may also be, for example, any film such as an SiOC film.

[0028] The second film 302 is, for example, an insulating film, and is formed on the first film 301. The second film 302 functions as an etching stop layer when etching the organic film 310. The second film 302 is a film containing silicon (Si) and oxygen (O). The second film 302 is, for example, a film containing tetraethoxysilane (TEOS), SiO ２ The second film 302 may be any of a silicon-containing film, ...

[0029] The organic film 310 is a film containing carbon (C) and is formed on the second film 302 of the film 300 to be etched. The organic film 310 is also referred to as the bottom layer (BL) of a three-layer mask (organic film 310, silicon-containing film 320, and photoresist film 330). The organic film 310 may be, for example, an amorphous carbon (a-C) film, a spin-on carbon (SOC) film, or the like.

[0030] The silicon-containing film 320 is a film containing silicon (Si) and is formed on the organic film 310. The silicon-containing film 320 is a film disposed in the middle layer of a three-layer mask (organic film 310, silicon-containing film 320, and photoresist film 330), and is also referred to as an ML (middle layer). The silicon-containing film 320 is a film containing silicon (Si) and carbon (C). The silicon-containing film 320 may be, for example, any film such as an SiOC film. The silicon-containing film 320 has a higher carbon (C) content than the second film 302.

[0031] The photoresist film 330 is an organic film in which a pattern of openings 335 is formed, and is formed on the silicon-containing film 320. The photoresist film 330 is the film disposed on the uppermost layer of a three-layer mask (organic film 310, silicon-containing film 320, and photoresist film 330). The photoresist film 330 is an organic film in which a pattern of openings 335 is formed by, for example, EUV (extreme ultraviolet) exposure. The pattern of openings 335 has a pattern of multiple circles arranged in a plan view of the substrate W from above.

[0032] In step S102, a pattern of openings 325 is formed in the silicon-containing film 320. FIG. 3B is a schematic cross-sectional view illustrating an example of the substrate W after processing in step S102. Here, the controller 2 controls the gas supply unit 20 to supply a third fluorine (F)-containing gas into the plasma processing chamber 10, controls the first RF generator 31a to supply a source RF signal to the upper electrode or the lower electrode, and controls the second RF generator 31b to supply a bias RF signal to the lower electrode. This generates plasma of the third fluorine (F)-containing gas, and etches the silicon-containing film 320 using the photoresist film 330 on which the pattern of openings 335 is formed as a mask, thereby forming the pattern of openings 325 in the silicon-containing film 320. The third fluorine (F)-containing gas may be the same gas as or different from the first fluorine (F)-containing gas described below. In this manner, through the processes from step S101 to step S102, a substrate W is prepared which is stacked with a film 300 to be etched, an organic film 310 formed on the film 300 to be etched, and a silicon-containing film 320 formed on the organic film 310 and having a pattern of openings 325 formed thereon.

[0033] In step S103, a pattern of openings 315 is formed in the organic film 310. FIG. 3C is a schematic cross-sectional view showing an example of the substrate W after the process in step S103. Here, the control unit 2 controls the gas supply unit 20 to supply a process gas (e.g., N ２ / H ２ Gas: N ２ Gas and H ２ The first RF generator 31a is controlled to supply a source RF signal to the upper electrode or the lower electrode, and the second RF generator 31b is controlled to supply a bias RF signal to the lower electrode. ２ / H ２ A plasma of the silicon-containing film (gas) is generated, and the organic film 310 is etched using the silicon-containing film 320 on which the pattern of the openings 325 is formed as a mask, thereby forming a pattern of the openings 315 in the organic film 310 .

[0034] In step S104, the silicon-containing film 320 is removed and the upper portion of the organic film 310 is trimmed. FIG. 3D is a schematic cross-sectional view illustrating an example of the substrate W after processing in step S104. Here, the controller 2 controls the gas supply unit 20 to supply a first fluorine (F)-containing gas into the plasma processing chamber 10, controls the first RF generator 31a to supply a source RF signal to the upper electrode or the lower electrode, and controls the second RF generator 31b to supply a bias RF signal to the lower electrode. This generates plasma of the first fluorine (F)-containing gas and removes the silicon-containing film 320. Furthermore, corners of the upper portion of the organic film 310 are trimmed, forming a sloped portion 311, widening the opening at the top of the organic film 310. Therefore, the hole diameter CD1 can be widened (CD0<CD1) compared to the hole diameter CD0 (see FIG. 3C) before the silicon-containing film 320 is removed. The first fluorine (F)-containing gas is a gas that selectively etches the silicon-containing film 320 relative to the second film 302. The first fluorine (F)-containing gas may be a gas that contains fluorine (F) but does not contain carbon (C), for example, NF ３ The gas supplied in step S104 may be a first fluorine (F)-containing gas (NF ３ gas), and a process gas (N ２ / H ２ The process gas for etching the organic film 310 may include nitrogen gas (NO2 gas) and argon gas (Ar gas). The process gas for etching the organic film 310 may be the same as or different from the gas used in step S103.

[0035] In step S105, a via etching process is performed on the target film 300. FIG. 3E is a cross-sectional view showing an example of the substrate W after the process in step S105. Here, the control unit 2 controls the gas supply unit 20 to supply a second fluorine (F)-containing gas into the plasma processing chamber 10, controls the first RF generator 31a to supply a source RF signal to the upper electrode or the lower electrode, and controls the second RF generator 31b to supply a bias RF signal to the lower electrode. This generates plasma of the second fluorine (F)-containing gas, and etches the target film 300 (the first film 301 and the second film 302) using the organic film 310 on which the pattern of the openings 315 is formed as a mask, thereby forming a pattern of openings 305 (vias, holes) in the target film 300. The second fluorine (F)-containing gas may be a gas containing fluorine (F) and carbon (C) (fluorocarbon gas), for example, C. ４ F ８ , C.F. ４ The gas may be any of the above.

[0036] In step S106, the organic film 310 is removed. Fig. 3F is a schematic cross-sectional view showing an example of the substrate W after the processing in step S106. Here, the control unit 2 removes the organic film 310 by ashing the organic film 310.

[0037] As described above, in the processes shown in steps S101 to S104, the organic film 310 having the pattern of the openings 315 can be formed on the film to be etched 300. Then, the organic film 310 having the pattern of the openings 315 can be used to form a pattern of the openings 305 (vias, holes) in the film to be etched 300.

[0038] Although the steps shown in steps S101 to S106 have been described as being performed in one plasma processing chamber 10, this is not limited to this, and for example, a configuration using multiple plasma processing chambers 10 may also be used.

[0039] Next, the effect of removing the silicon-containing film 320 and trimming the upper portion of the organic film 310 in step S104 will be described with reference to FIGS. 4 and 5. FIG. 4 is an example of a schematic cross-sectional view of a substrate W subjected to the via etching process of this embodiment. FIG. 5 is an example of a schematic cross-sectional view of a substrate W subjected to the via etching process of a reference example. In the via etching process of the reference example, step S104 was omitted, and the via etching process (see step S105) was performed in a state where the silicon-containing film 320 remained on the organic film 310 (see FIG. 3C ).

[0040] Here, the larger the diameter of the via (opening 305) in the film 300 to be etched, the more easily activated species (CF radicals) 400 of the fluorine-containing gas are supplied into the via, and deposits accumulate on the sidewalls of the via to protect the sidewalls. That is, the thickness of deposits accumulated on the sidewalls of vias (openings 305) with larger diameters is greater than that of vias (openings 305) with smaller diameters. This improves the variation in via diameters among multiple vias formed in the film 300 to be etched.

[0041] First, the via etching process (see FIG. 5 ) in the reference example will be described. As shown in FIG. 3C , after the opening 315 is formed in the organic film 310 by the process of step S103, the silicon-containing film 320 remains on the organic film 310, narrowing the hole diameter CD0 at the top of the organic film 310. Therefore, as shown in FIG. 5 , in the via etching process in the reference example, deposits accumulate in a region A21 at the top of the sidewall of the organic film 310, causing non-uniform clogging, resulting in non-uniform narrowing of the opening diameter in the organic film 310. Furthermore, the non-uniform narrowing of the opening in the organic film 310 also increases the variation in the via diameter CD2 (see FIG. 3F ) of the multiple vias (openings 305) formed in the target film 300 to be etched.

[0042] Furthermore, in the via etching process of the reference example, the opening becomes narrower in region A21, so that a sufficient amount of activated species (CF radicals) 400 of the fluorine-containing gas is not supplied to region A22 within the via of the film 300 to be etched, and the effect of improving the variation in the via diameter CD2 (see FIG. 3F) becomes insufficient.

[0043] Next, the via etching process (see FIG. 4 ) in this embodiment will be described. As shown in FIG. 3D , the silicon-containing film 320 on the organic film 310 is removed by the process of step S104, and the hole diameter CD1 in the upper part of the organic film 310 is enlarged. Therefore, as shown in FIG. 4 , the via etching process in this embodiment suppresses clogging in an area A11 on the upper part of the sidewall of the organic film 310. This suppresses variation in the via diameter CD2 (see FIG. 3F ) of multiple vias (openings 305) formed in the target film 300 to be etched.

[0044] Furthermore, in the via etching process of this embodiment, a sufficient amount of activated species (CF radicals) 400 of the fluorine-containing gas can be supplied to the region A12 in the via of the film to be etched 300. As a result, deposits are accumulated on the sidewalls of the vias to protect the sidewalls, thereby suppressing variations in the via diameters CD2 (see FIG. 3F ) of the multiple vias (openings 305) formed in the film to be etched 300.

[0045] Next, the first fluorine (F)-containing gas used in the process of removing the silicon-containing film 320 in step S104 will be described with reference to FIGS. 6 and 7. FIG. 6 is an example of a schematic cross-sectional view of the substrate W during the process of removing the silicon-containing film 320 according to the present embodiment. FIG. 7 is an example of a schematic cross-sectional view of the substrate W during the process of removing the silicon-containing film 320 according to a reference example. In the following description, it is assumed that the silicon-containing film 320 is, for example, a SiOC film, and the second film 302 is, for example, a TEOS film.

[0046] First, the process of removing the silicon-containing film 320 in the reference example (see FIG. 7) will be described. Here, a fluorocarbon gas (C) is used as the first fluorine (F)-containing gas. ４ F８ , C.F. ４ The following describes an example where the following is used:

[0047] The first fluorine (F)-containing gas is a fluorocarbon gas (C ４ F ８ , C.F. ４ By using a etching gas such as a silicon-containing film 320, not only the silicon-containing film 320 but also the second film 302 is etched. As a result, a recess having a depth H2 is formed in the second film 302. Due to the recess being formed in the second film 302 in this manner, when the via etching process is performed on the target film 300 in step S105, there is a risk that the variation in the diameters of the vias (openings 305) will increase.

[0048] Next, a process for removing the silicon-containing film 320 in this embodiment (see FIG. 7) will be described. Here, NF is used as the first fluorine (F)-containing gas. ３ The following will be explained using an example where NF is used. ３ has a high etching rate with respect to the silicon-containing film 320 (e.g., a SiOC film) having a high carbon (C) content, and a low etching rate with respect to the second film 302 (e.g., a TEOS film) having a low carbon (C) content. This allows the silicon-containing film 320 to be selectively etched relative to the second film 302. Consequently, a recess having a depth H1 is formed in the second film 302. That is, the depth of the recess can be suppressed (H1<H2). By suppressing the depth of the recess formed in the second film 302 in this way, variation in the diameter of the vias (openings 305) can be suppressed when the via etching process is performed on the target film 300 in step S105.

[0049] The embodiments disclosed above include, for example, the following aspects. (Supplementary Note 1) A substrate processing method comprising the steps of: preparing a substrate on which a film to be etched, an organic film formed on the film to be etched, and a silicon-containing film formed on the organic film and having an opening pattern formed therein; forming an opening pattern in the organic film using the silicon-containing film as a mask; and, after forming the opening pattern in the organic film, removing the silicon-containing film to widen the opening in the upper part of the organic film. (Supplementary Note 2) The film to be etched comprises a first film and a second film formed on the first film, and the second film has a lower carbon content than the silicon-containing film. (Supplementary Note 3) The second film is a TEOS film, a SiO ２ The substrate processing method according to claim 2, wherein the silicon-containing film is a silicon-containing film or a silicon-containing film, and the silicon-containing film is a silicon-oxide film. (Supplementary Note 4) The substrate processing method according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the step of removing the silicon-containing film and widening the opening in the upper part of the organic film comprises supplying plasma of a first fluorine-containing gas to the substrate. (Supplementary Note 5) The first fluorine-containing gas is NF ３ The substrate processing method according to any one of Supplementary Note 4 to Supplementary Note 5, wherein the step of removing the silicon-containing film and widening the opening in the upper part of the organic film comprises supplying to the substrate a plasma of the first fluorine-containing gas and a process gas that etches the organic film. ２ Gas and H ２The substrate processing method according to Appendix 6, wherein the gas is a mixed gas of a silicon-containing film and a silicon-containing gas. (Appendix 8) The substrate processing method according to any one of Appendixes 1 to 7, further comprising, after the step of removing the silicon-containing film and widening the opening in the upper part of the organic film, a step of forming an opening pattern in the film to be etched using the organic film as a mask. (Appendix 9) The substrate processing method according to Appendix 8, wherein the step of forming an opening pattern in the film to be etched uses plasma of a second fluorine-containing gas. (Appendix 10) The substrate processing method according to Appendix 9, wherein the second fluorine-containing gas is a fluorocarbon gas. (Appendix 11) The substrate processing method according to any one of Appendixes 1 to 10, further comprising, after the step of forming an opening pattern in the film to be etched, a step of removing the organic film. (Supplementary Note 12) The substrate processing method according to any one of Supplementary Note 1 to Supplementary Note 11, wherein the step of preparing a substrate includes the steps of: preparing a substrate including the film to be etched, the organic film formed on the film to be etched, the silicon-containing film formed on the organic film, and a photoresist film formed on the silicon-containing film and having an opening pattern formed thereon; and forming an opening pattern in the silicon-containing film using the photoresist film as a mask. (Supplementary Note 13) The substrate processing method according to Supplementary Note 12, wherein the step of forming an opening pattern in the silicon-containing film uses plasma of a third fluorine-containing gas. (Supplementary Note 14) A plasma processing apparatus comprising: a substrate support part that supports a substrate on which a film to be etched, an organic film formed on the film to be etched, and a silicon-containing film formed on the organic film and having an opening pattern formed thereon; a plasma processing chamber that houses the substrate support part; a gas inlet part that introduces gas into the plasma processing chamber; a plasma generation part that generates plasma in the plasma processing chamber; and a control part; the plasma processing apparatus performs the steps of: forming an opening pattern in the organic film using the silicon-containing film as a mask; and, after forming the opening pattern in the organic film, removing the silicon-containing film to widen the opening in the upper part of the organic film.

[0050] The present invention is not limited to the configurations described in the above embodiments, but may be combined with other elements, etc. These aspects can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form.

[0051] This application claims priority based on Japanese Patent Application No. 2024-026770, filed on February 26, 2024, the entire contents of which are incorporated herein by reference.

[0052] REFERENCE SIGNS LIST W substrate 1 plasma processing apparatus 2 control unit 10 plasma processing chamber 11 substrate support unit 13 shower head (gas inlet unit) 30 power supply 31a first RF generating unit (plasma generating unit) 300 film to be etched 301 first film 302 second film 310 organic film 320 silicon-containing film 330 photoresist film 305, 315, 325, 335 openings

Claims

1. A substrate processing method comprising the steps of: preparing a substrate having a layered structure including a film to be etched, an organic film formed on the film to be etched, and a silicon-containing film formed on the organic film and having an opening pattern formed therein; forming an opening pattern in the organic film using the silicon-containing film as a mask; and, after forming the opening pattern in the organic film, removing the silicon-containing film to widen the opening in the upper part of the organic film.

2. The substrate processing method according to claim 1, wherein the film to be etched comprises a first film and a second film formed on the first film, and the second film has a lower carbon content than the silicon-containing film.

3. The second film is a TEOS film, SiO ２ The substrate processing method according to claim 2 , wherein the silicon-containing film is a SiOC film.

4. The substrate processing method according to any one of claims 1 to 3, wherein the step of removing the silicon-containing film and widening the opening in the upper part of the organic film comprises supplying plasma of a first fluorine-containing gas to the substrate.

5. The first fluorine-containing gas is NF ３ The substrate processing method according to claim 4 , wherein the gas is a gas.

6. The substrate processing method according to claim 4, wherein the step of removing the silicon-containing film and widening the opening in the upper part of the organic film comprises supplying to the substrate a plasma of the first fluorine-containing gas and a process gas that etches the organic film.

7. The process gas is N ２ Gas and H ２ The substrate processing method according to claim 6 , wherein the gas is a mixture of gases.

8. The substrate processing method according to claim 1, further comprising the step of forming an opening pattern in the film to be etched using the organic film as a mask after the step of removing the silicon-containing film and widening the opening in the upper part of the organic film.

9. The substrate processing method according to claim 8, wherein the step of forming an opening pattern in the film to be etched uses plasma of a second fluorine-containing gas.

10. The substrate processing method according to claim 9, wherein the second fluorine-containing gas is a fluorocarbon gas.

11. The substrate processing method according to claim 1, further comprising the step of removing the organic film after forming an opening pattern in the film to be etched.

12. The substrate processing method according to claim 1, wherein the step of preparing the substrate comprises the steps of: preparing a substrate on which the film to be etched, the organic film formed on the film to be etched, the silicon-containing film formed on the organic film, and a photoresist film formed on the silicon-containing film and having an opening pattern formed thereon, are stacked; and forming an opening pattern in the silicon-containing film using the photoresist film as a mask.

13. The substrate processing method according to claim 12, wherein the step of forming an opening pattern in the silicon-containing film uses plasma of a third fluorine-containing gas.

14. A plasma processing apparatus comprising: a substrate support part for supporting a substrate having a layered structure including a film to be etched, an organic film formed on the film to be etched, and a silicon-containing film formed on the organic film and having an opening pattern formed therein; a plasma processing chamber accommodating the substrate support part; a gas inlet part for introducing gas into the plasma processing chamber; a plasma generation part for generating plasma in the plasma processing chamber; and a control part; the plasma processing apparatus performing the steps of: forming an opening pattern in the organic film using the silicon-containing film as a mask; and, after forming the opening pattern in the organic film, removing the silicon-containing film to widen the opening in the upper part of the organic film.

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