Substrate Processing Method and Substrate Processing Apparatus

Abstract

In the present invention, a substrate that includes a tin-containing film is appropriately etched. In one illustrative embodiment, a substrate processing method is provided. This substrate processing method comprises: a preparation step for preparing a substrate that includes a carbon-containing film, an intermediate film that is provided on the carbon-containing film, and a tin-containing film that is provided on the intermediate film and that has an aperture pattern; a first etching step for etching the intermediate film, with the tin-containing film being used as a mask, so as to transfer the aperture pattern onto the intermediate film; and a second etching step in which plasma generated from a processing gas containing hydrogen, halogen or carbon, and oxygen is used to remove the tin-containing film, and the carbon-containing film is etched with the intermediate film being used as a mask.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] Patent Document 1 discloses a technique for equalizing the dimensions of a pattern formed in a resist by trimming a non-organic resist using a processing gas containing CH3F or BCl3.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for appropriately etching a substrate including a tin-containing film.

Means for Solving the Problems

[0005] In one embodiment of the present disclosure, a substrate processing method is provided. The substrate processing method includes a preparation step of preparing a substrate including a carbon-containing film, an intermediate film provided on the carbon-containing film, and a tin-containing film provided on the intermediate film and having an opening pattern; a first etching step of etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film; and a second etching step of removing the tin-containing film and etching the carbon-containing film using the intermediate film as a mask using plasma generated from a processing gas containing hydrogen, a halogen or carbon, and oxygen.

[0006] In one embodiment of the present disclosure, a substrate processing apparatus is provided. The substrate processing apparatus includes a plasma processing chamber, a gas supply unit that supplies a processing gas to the plasma processing chamber, a power supply that supplies power for generating plasma in the plasma processing chamber, and a control unit. The control unit places a substrate in the plasma processing chamber, the substrate including a carbon-containing film, an intermediate film provided on the carbon-containing film, and a tin-containing film provided on the intermediate film and having an opening pattern. The control unit etches the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film, supplies a processing gas containing hydrogen, a halogen or carbon, and oxygen from the gas supply unit to the plasma processing chamber, generates plasma in the plasma processing chamber by the power applied from the power supply, removes the tin-containing film, and etches the carbon-containing film using the intermediate film as a mask, and executes control.

Advantages of the Invention

[0007] According to an exemplary embodiment of the present disclosure, a technique for appropriately etching a substrate including a tin-containing film can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9

Embodiments for Carrying Out the Invention

[0009] Hereinafter, each embodiment of the present disclosure will be described.

[0010] In one exemplary embodiment, a substrate processing method is provided. The substrate processing method includes a preparation step of preparing a substrate including a carbon-containing film, an intermediate film provided on the carbon-containing film, and a tin-containing film provided on the intermediate film and having an opening pattern, a first etching step of etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film, and a second etching step of removing the tin-containing film and etching the carbon-containing film using the intermediate film as a mask using plasma generated from a processing gas containing hydrogen, a halogen or carbon, and oxygen.

[0011] In one exemplary embodiment, before the first etching step, a step of trimming at least the sidewalls of the tin-containing film using plasma generated from a gas containing at least one selected from the group consisting of hydrogen, a halogen, and carbon is further provided.

[0012] In one exemplary embodiment, the gas containing at least one selected from the group consisting of hydrogen, a halogen, and carbon is at least one gas selected from the group consisting of H2 gas, HBr gas, HCl gas, HI gas, CH4 gas, CHF3 gas, Cl2 gas, CO gas, and Br2 gas.

[0013] In one exemplary embodiment, before the first etching step, the method further comprises a step of trimming at least sidewalls of the tin-containing film using hydrogen halide.

[0014] In one exemplary embodiment, the hydrogen halide is at least one gas selected from the group consisting of HBr gas, HCl gas, and HI gas.

[0015] In one exemplary embodiment, the tin-containing film is a photoresist film formed on an intermediate film.

[0016] In one exemplary embodiment, the substrate prepared in the preparation step includes residues extending toward other portions of the sidewall on a part of the sidewall of the tin-containing film.

[0017] In one exemplary embodiment, the processing gas includes a gas composed of molecules containing any one of Br, Cl, and I.

[0018] In one exemplary embodiment, the processing gas includes CH3OH gas or a mixed gas of CH4 gas and O2 gas.

[0019] In one exemplary embodiment, the processing gas includes an inert gas.

[0020] In one exemplary embodiment, the intermediate film is a spin-on glass (SOG) film, a SiON film, a SiC film, or a Si-containing antireflection film (SiARC).

[0021] In one exemplary embodiment, the carbon-containing film is a spin-on carbon (SOC) film or an amorphous carbon film (ACL).

[0022] In one exemplary embodiment, the carbon-containing film is formed on an underlying film, and after the second etching step, the method further comprises a third etching step of etching the underlying film using the carbon-containing film as a mask.

[0023] In one exemplary embodiment, a substrate processing method is provided. The substrate processing method includes a preparation step of preparing a substrate including an intermediate film provided on a carbon-containing film and a tin-containing film provided on the intermediate film and having an opening pattern, a first etching step of etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film, a step of removing the tin-containing film, and a second etching step of etching the carbon-containing film using the intermediate film as a mask using plasma generated from a processing gas including hydrogen, a halogen or carbon, and oxygen.

[0024] In one exemplary embodiment, the step of removing the tin-containing film includes etching the tin-containing film using plasma generated from a gas including at least one selected from the group consisting of hydrogen, a halogen, and carbon.

[0025] In one exemplary embodiment, the gas including at least one selected from the group consisting of hydrogen, a halogen, and carbon is at least one gas selected from the group consisting of H2 gas, HBr gas, HCl gas, HI gas, CH4 gas, CHF3 gas, Cl2 gas, CO gas, and Br2 gas.

[0026] In one exemplary embodiment, the step of removing the tin-containing film includes removing the tin-containing film using hydrogen halide.

[0027] In one exemplary embodiment, the hydrogen halide is at least one gas selected from the group consisting of HBr gas, HCl gas, and HI gas.

[0028] In one exemplary embodiment, a substrate processing apparatus is provided. The substrate processing apparatus includes a plasma processing chamber, a gas supply unit that supplies a processing gas to the plasma processing chamber, a power supply that supplies power for generating plasma in the plasma processing chamber, and a control unit. The control unit disposes a substrate in the plasma processing chamber, the substrate including a carbon-containing film, an intermediate film provided on the carbon-containing film, and a tin-containing film provided on the intermediate film and having an opening pattern. The control unit etches the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film, supplies a processing gas containing hydrogen, a halogen or carbon, and oxygen from the gas supply unit to the plasma processing chamber, generates plasma in the plasma processing chamber by the power applied from the power supply, removes the tin-containing film, and etches the carbon-containing film using the intermediate film as a mask, and executes control.

[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 denoted by the same reference numerals, and redundant descriptions are omitted. Unless otherwise specified, the positional relationships such as up, down, left, and right are 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] <Configuration of Substrate Processing Apparatus 1> FIG. 1 is a diagram schematically showing a substrate processing apparatus 1 according to one exemplary embodiment. A substrate processing method according to one exemplary embodiment (hereinafter referred to as "the present processing method") may be executed using the substrate processing apparatus 1.

[0031] The substrate processing apparatus 1 is a capacitively coupled plasma processing apparatus. The substrate processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, an exhaust system 40, and a control unit 50. Further, the substrate processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one exemplary embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas discharge port for discharging gas from the plasma processing space. The side wall 10a is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the plasma processing chamber 10 housing.

[0032] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. In one exemplary embodiment, the main body portion 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Also, although not shown, the substrate support portion 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0033] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. Note that the gas introduction part may include, in addition to the shower head 13, one or a plurality of side gas injectors (SGIs) attached to one or a plurality of openings formed in the side wall 10a.

[0034] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one exemplary embodiment, the gas supply unit 20 is configured to supply at least one processing gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include one or more flow modulation devices for modulating or pulsing the flow rate of at least one processing 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), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support 11 and / or the conductive member of the shower head 13. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Further, by supplying a bias RF signal to the conductive member of the substrate support 11, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0036] In one exemplary embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13 via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one exemplary embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one exemplary embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support unit 11 and / or the conductive member of the shower head 13. The second RF generation unit 31b is coupled to the conductive member of the substrate support unit 11 via at least one impedance matching circuit, and is configured to generate a bias RF signal (bias RF power). In one exemplary embodiment, the bias RF signal has a frequency lower than that of the source RF signal. In one exemplary embodiment, the bias RF signal has a frequency in the range of 400 kHz to 40 MHz. In one exemplary embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the conductive member of the substrate support unit 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0037] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one exemplary embodiment, the first DC generation unit 32a is connected to the conductive member of the substrate support 11 and configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one exemplary embodiment, the first DC signal may be applied to other electrodes such as the electrodes within the electrostatic chuck. In one exemplary embodiment, the second DC generation unit 32b is connected to the conductive member of the shower head 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the shower head 13. In various embodiments, at least one of the first and second DC signals may be pulsed. Note that the first and second DC generation units 32a, 32b may be provided in addition to the RF power supply 31, and the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0038] The exhaust system 40 may be connected to, for example, a gas outlet 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 within the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0039] The control unit 50 processes computer-executable instructions that cause the substrate processing apparatus 1 to execute various processes described in the present disclosure. The control unit 50 may be configured to control each element of the substrate processing apparatus 1 so as to execute the various processes described herein. In one exemplary embodiment, part or all of the control unit 50 may be provided as part of the configuration of a device external to the substrate processing apparatus 1. The control unit 50 may include, for example, a computer 50a. The computer 50a may include, for example, a processing unit (CPU: Central Processing Unit) 50a1, a storage unit 50a2, and a communication interface 50a3. The processing unit 50a1 may be configured to perform various control operations based on a program stored in the storage unit 50a2. The storage unit 50a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 50a3 may communicate with other components of the substrate processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0040] <Configuration of the substrate processing system PS> FIG. 2 is a diagram schematically showing a substrate processing system PS according to one exemplary embodiment. The present processing method may be executed using the substrate processing system PS.

[0041] The substrate processing system PS includes substrate processing chambers PM1 to PM6 (hereinafter also collectively referred to as "substrate processing modules PM"), a transfer module TM, load lock modules LLM1 and LLM2 (hereinafter also collectively referred to as "load lock modules LLM"), a loader module LM, and load ports LP1 to LP3 (hereinafter also collectively referred to as "load ports LP"). The control unit CT controls each component of the substrate processing system PS to execute a predetermined process on the substrate W.

[0042] The substrate processing module PM performs processes such as etching, trimming, film formation, annealing, doping, lithography, cleaning, and ashing on the substrate W inside it. A part of the substrate processing module PM may be a measurement module, and may measure the film thickness of the film formed on the substrate W, the dimensions of the pattern formed on the substrate W, and the like. The substrate processing apparatus 1 shown in FIG. 1 is an example of the substrate processing module PM.

[0043] The transfer module TM has a transfer device for transferring the substrate W, and transfers the substrate W between the substrate processing modules PM or between the substrate processing module PM and the load lock module LLM. The substrate processing module PM and the load lock module LLM are arranged adjacent to the transfer module TM. The transfer module TM, the substrate processing module PM, and the load lock module LLM are spatially isolated or connected by an openable and closable gate valve.

[0044] The load lock modules LLM1 and LLM2 are provided between the transfer module TM and the loader module LM. The load lock module LLM can switch the internal pressure to atmospheric pressure or vacuum. The load lock module LLM transfers the substrate W from the loader module LM at atmospheric pressure to the transfer module TM at vacuum, and also transfers it from the transfer module TM at vacuum to the loader module LM at atmospheric pressure.

[0045] The loader module LM has a transfer device for transferring the substrate W, and transfers the substrate W between the load lock module LLM and the load board LP. Inside the load port LP, for example, a FOUP (Front Opening Unified Pod) capable of accommodating 25 substrates W or an empty FOUP can be placed. The loader module LM takes out the substrate W from the FOUP in the load port LP and transfers it to the load lock module LLM. Also, the loader module LM takes out the substrate W from the load lock module LLM and transfers it to the FOUP in the load board LP.

[0046] The control unit CT controls each component of the substrate processing system PS to execute a predetermined process on the substrate W. The control unit CT stores a recipe in which the procedure of the process, the conditions of the process, the transfer conditions, etc. are set, and controls each component of the substrate processing system PS so as to execute a predetermined process on the substrate W according to the recipe. The control unit CT may have some or all of the functions of the control unit 50 of the substrate processing apparatus 1 shown in FIG. 1.

[0047] <An example of this processing method> FIG. 3 is a flowchart showing this processing method. As shown in FIG. 3, this processing method includes a step of preparing the substrate W (preparation step: step ST1), a step of etching the intermediate film (first etching step: step ST2), and a step of etching the carbon-containing film (second etching step: step ST3).

[0048] Hereinafter, an example of this processing method shown in FIG. 3 will be described with reference to FIGS. 4A to 4C, FIGS. 5A, 5B, and 6. Hereinafter, a case where the control unit 50 controls each part of the substrate processing apparatus 1 (see FIG. 1) to execute this processing method will be described as an example.

[0049] FIG. 4A shows an example of the cross-sectional structure of the substrate W after the processing in step ST1. FIG. 4B shows an example of the cross-sectional structure of the substrate W after the processing in step ST2. FIG. 4C shows an example of the cross-sectional structure of the substrate W after the processing in step ST3.

[0050] (Preparation of the substrate W: step ST1) In step ST1, the substrate W is prepared. The substrate W is disposed in the plasma processing space 10s (see FIG. 1). In the plasma processing space 10s, the substrate W is placed on the substrate support surface 111a of the substrate support portion 11 and held by an electrostatic chuck. At least a part of the process for forming each component of the substrate W may be performed in the plasma processing space 10s. Further, after all or part of each component of the substrate W is formed by a device or chamber outside the substrate processing apparatus 1, the substrate W may be disposed in the plasma processing space 10s.

[0051] The substrate W prepared in step ST1 is formed, for example, by laminating a base film 101, a carbon-containing film 102, an intermediate film 103, and a tin-containing film 104 in this order (see FIG. 4A).

[0052] The base film 101 may be, for example, a silicon-containing film such as Si, SiC, SiON, SiN, and / or SiO2. The base film 101 may have different etching characteristics from the carbon-containing film 102 and may be formed of a material that is selectively etched with respect to the carbon-containing film 102. The base film 101 may be composed of a plurality of films laminated, for example, a dielectric film such as a silicon oxide film or a silicon nitride film may be laminated on a silicon film to form the base film 101.

[0053] The carbon-containing film 102 may be any film containing carbon, for example, a spin-on carbon (SOC) film or an amorphous carbon layer (ACL).

[0054] The intermediate film 103 is, for example, a spin-on glass (SOG) film, a SiON film, a SiC film, a silicon-containing antireflection film (SiARC), etc. The intermediate film 103 may be composed of a plurality of films laminated, for example, an antireflection film (BARC) may be laminated on a SiON film to form the intermediate film 103. The intermediate film 103 may have different etching characteristics from the carbon-containing film 102 and may have, for example, oxygen plasma resistance.

[0055] The tin-containing film 104 contains, for example, tin oxide and / or tin hydroxide. The tin-containing film 104 may contain an organic substance. The tin-containing film 104 may be, for example, a photoresist film.

[0056] Each film (base film 101, carbon-containing film 102, intermediate film 103, and / or tin-containing film 104) constituting the substrate W may be formed by, for example, a CVD method, an ALD method, a spin coating method, etc. Each of the above films may be a flat film or a film having irregularities.

[0057] The tin-containing film 104 has an opening pattern. The opening pattern defines at least one opening OP on the intermediate film 103 (see FIG. 4A). The opening OP is a space on the intermediate film 103 and is surrounded by the side walls SS of the tin-containing film. As shown in FIG. 4A, the intermediate film 103 has a region covered by the tin-containing film 104 and a region exposed at the bottom of the opening OP.

[0058] The opening pattern of the tin-containing film 104 may have an arbitrary shape in a plan view of the substrate W (when the substrate W is viewed from top to bottom in FIG. 4A). The opening pattern may be, for example, a line-and-space (L / S) pattern in which a plurality of linearly-shaped openings OP are arranged at regular intervals in a plan view, or an array pattern in which a plurality of hole-shaped openings OP such as circles, ellipses, rectangles, etc. are arranged in a plan view.

[0059] The opening pattern of the tin-containing film 104 may be formed, for example, by lithography. Specifically, for example, a photoresist film is formed on the intermediate film 103, and selectively irradiated with light (e.g., EUV excimer laser, etc.) using an exposure mask. Then, the irradiated photoresist film is developed. Thereby, the opening pattern of the tin-containing film 104 may be formed. The opening pattern may be, for example, a line-and-space (L / S) pattern. Also, for example, the opening pattern of the tin-containing film may be formed by etching.

[0060] (Etching of the intermediate film: Step ST2) In step ST2, the intermediate film 103 is etched. Specifically, for example, a processing gas is supplied from the gas supply unit 20 into the plasma processing space 10s, and an RF signal is supplied from the RF power supply 31 to the plasma processing space 10s (see FIG. 1). Thereby, plasma is generated in the plasma processing space 10s, and the active species in the plasma are attracted to the substrate W. At this time, the tin-containing film 104 functions as a mask, and the intermediate film 103 is anisotropically etched in the depth direction of the opening OP (the direction from top to bottom in FIG. 4A) from the exposed portion at the bottom of the opening OP (see FIG. 4A). Thereby, the opening pattern of the tin-containing film 104 is transferred to the intermediate film 103 (see FIG. 4B). Note that in the etching of the intermediate film 103, a part of the tin-containing film 104 may be etched.

[0061] When the intermediate film 103 is a silicon-containing film such as a silicon oxide film, a silicon nitride film, or a silicon carbide film, the processing gas used in the etching of the intermediate film 103 may be a fluorocarbon gas and / or a hydrofluorocarbon gas. The fluorocarbon gas is, for example, CF4, C4F6, C4F8, etc. The hydrofluorocarbon gas is CHF3, CH3F, etc.

[0062] Here, the tin-containing film 104 used as a mask may have defects in the opening pattern. The defects can be, for example, scum or microbridges in a line and space (L / S) pattern. The defects can be, for example, defects when an opening pattern is formed by lithography on a photoresist film.

[0063] FIG. 5A is a diagram showing an example of the cross-sectional structure of the substrate W before the processing in step ST2. FIG. 5B is a diagram showing an example of the cross-sectional structure of the substrate W after the processing in step ST2. FIGS. 5A and 5B are an example of the etching of the defect portion when the opening pattern of the tin-containing film 104 has a defect.

[0064] As shown in FIG. 5A, the defect of the opening pattern of the tin-containing film 104 can be, for example, a residue DF extending from a part of the side wall SS1 of the tin-containing film 104 toward the central portion of the opening OP or other parts of the side wall SS1 (for example, the part facing the above-mentioned part of the side wall SS1 across the opening OP). The residue DF may be formed across the above-mentioned part and the other part of the side wall SS1. The exposed portion of the intermediate film 103 at the bottom of the opening OP is narrower by the amount of the residue DF than the defect-free portion (see FIG. 4A).

[0065] The residue DF of the tin-containing film 104 functions as a part of the mask in the etching of step ST2. Therefore, as shown in FIG. 5B, after the treatment by step ST2, the intermediate film 103 below the residue DF remains without being etched. That is, the defect of the opening pattern of the tin-containing film 104 can be transferred to the opening pattern transferred to the intermediate film 103 by step ST2.

[0066] (Etching of the carbon-containing film 102: step ST3) In step ST3, the carbon-containing film 102 is etched (see FIG. 4C). Specifically, for example, a processing gas is supplied from the gas supply unit 20 into the plasma processing space 10s, and an RF signal is supplied from the RF power supply 31 to the plasma processing space 10s (see FIG. 1). Thereby, plasma is generated in the plasma processing space 10s, and the active species in the plasma are attracted to the substrate W.

[0067] The processing gas contains hydrogen, halogen or carbon, and oxygen. The processing gas may include, for example, one or more gases composed of molecules containing H, Br and / or Cl, I (for example, H2, Br2, Cl2, HBr and / or HCl, HI, etc.). The processing gas may include, for example, one or more gases composed of molecules containing O (for example, O2, CO2 and / or COS, etc.). The processing gas may include, for example, CH3OH gas, and may also include CH4 gas and O2 gas. The processing gas may further include an inert gas such as He, Ar, N2, etc.

[0068] As a result, the tin-containing film 104 is removed, and the intermediate film 103 functions as a mask. The carbon-containing film 102 is anisotropically etched in the depth direction of the opening OP from the exposed portion at the bottom of the opening OP (see FIG. 4B). As a result, an opening pattern corresponding to the opening pattern of the intermediate film 103 is formed in the carbon-containing film 102 (see FIG. 4C). Note that, in the etching of the carbon-containing film 102, a part of the intermediate film 103 may be etched.

[0069] Here, the opening pattern of the intermediate film 103 may have a defect. For example, as described with reference to FIGS. 5A and 5B, when the opening pattern of the tin-containing film 104 has a defect, the defect can be transferred to the intermediate film 103 by the etching in step ST2.

[0070] As shown in FIG. 5B, the defect (residue DF) of the opening pattern of the tin-containing film 104 is transferred to the opening pattern of the intermediate film 103. The exposed portion of the carbon-containing film 102 at the bottom of the opening OP is narrower by the amount of the residue DF than the portion without a defect (see FIG. 4B).

[0071] FIG. 6 is a diagram showing an example of the cross-sectional structure of the substrate W after the process in step ST3. FIG. 6 is an example of the etching of a defective portion when the opening pattern of the intermediate film 103 has a defect.

[0072] In step ST3, plasma is generated using a processing gas containing hydrogen, halogen, or carbon, and oxygen. As a result, any two or more of the following processes can proceed simultaneously. Such processes include, for example, (i) removal of the tin-containing film 104 mainly by hydrogen, halogen, and carbon in the plasma (including removal of tin scattered from the tin-containing film 104), (ii) removal of the defect of the opening pattern of the intermediate film 103 mainly by hydrogen and halogen in the plasma, (iii) anisotropic etching of the carbon-containing film mainly by oxygen in the plasma, and (iv) formation of a protective film PF on the sidewall of the carbon-containing film 102 by the binding of halogen or carbon mainly in the plasma to the carbon of the carbon-containing film 102.

[0073] For example, in step ST3, while defects in the opening pattern of the intermediate film 103 used as a mask are removed (the above (ii)), the carbon-containing film 102 can be etched (the above (iii)). As a result, transfer of defects in the intermediate film 103 to the opening pattern formed in the carbon-containing film 102 is suppressed (see FIG. 6). Therefore, this processing method can uniformize the dimensions and / or shape of the opening pattern formed in the carbon-containing film 102. For example, when the opening pattern is a line and space (L / S) pattern, an increase in line edge roughness (LER) and line width roughness (LWR) can be suppressed.

[0074] For example, in step ST3, while the tin-containing film 104 and tin scattered from the tin-containing film 104 are removed (the above (i)), the carbon-containing film 102 can be etched (the above (iii)). As a result, adhesion of tin scattered from the tin-containing film 104 to the substrate W can be suppressed. Further, since the substrate W after the treatment in step ST3 does not have the tin-containing film 104 (see FIG. 6), a step of removing the tin-containing film 104 does not need to be provided separately, and the throughput can be improved. As will be described later, in this processing method, a step of removing the tin-containing film 104 may be provided separately before step ST3.

[0075] For example, in step ST3, while the protective film PF is formed on the sidewall surface of the carbon-containing film 102 (the above (iv)), the carbon-containing film 102 can be etched (the above (iii)). As a result, this processing method can control the dimensions and / or shape of the opening pattern formed in the carbon-containing film 102. For example, when the opening pattern is a line and space (L / S) pattern, the line CD and the space CD can be controlled within a desired range.

[0076] In addition, when the base film 101 is an etching target film, this processing method may include a step of etching the base film 101 using the carbon-containing film 102 as a mask after the completion of step ST3. For example, when the base film 101 is an etching target film such as a silicon oxide film or a silicon nitride film, the processing gas used for etching may be a fluorocarbon gas and / or a hydrofluorocarbon gas. Thereby, the opening pattern of the carbon-containing film 102 is transferred to the base film 101. In this case, the carbon-containing film 102 functions as one of the three-layer multi-masks together with the intermediate film 103 and the tin-containing film 104.

[0077] <Another Example of This Processing Method> FIG. 7 is a flowchart showing another example 1 of this processing method. Hereinafter, another example 1 of this processing method will be described along the flowchart shown in FIG. 7 while referring to FIGS. 3 to 6, FIGS. 8A and 8B. The example shown in FIG. 7 further has a step of trimming the tin-containing film 104 (step ST1a) in addition to the example shown in FIG. 3. Step ST1a is executed between step ST1 and step ST2.

[0078] In step ST1a, at least the sidewalls of the tin-containing film 104 are trimmed. Trimming includes a process of etching the sidewalls and removing a process accompanied by a change in CD or residues. Trimming may be performed, for example, by etching the tin-containing film 104 using a plasma of a processing gas (trimming gas) containing at least one selected from the group consisting of hydrogen, halogen, and carbon. The trimming gas may be a gas containing hydrogen or carbon, for example, H2, HBr, HCl, HI, CH4, CHF3, CO, etc. The trimming gas may be a processing gas containing halogen, for example, a gas not containing hydrogen such as Cl2 gas, Br2 gas, etc. During trimming, a bias RF signal or a bias DC signal may be supplied to the substrate support portion 11 to generate a bias potential between the plasma and the substrate W. Also, during trimming, it may not be necessary to generate a bias potential between the plasma and the substrate W. In this case, the target temperature of the substrate W may be made higher than that in the case of generating a bias potential to promote the volatilization of reaction products (for example, tin halide). Note that trimming may not use plasma. For example, trimming may be performed by etching the tin-containing film 104 by a chemical reaction with a gas of hydrogen halide. The hydrogen halide may be, for example, HBr, HCl, HI, etc. The trimming gas may further contain an inert gas (Ar, N2, etc.). By trimming at least the sidewalls of the tin-containing film 104, defects in the opening pattern of the tin-containing film 104 are removed or suppressed. This point will be described below with reference to FIGS. 8A and 8B.

[0079] FIG. 8A is a diagram showing an example of a cross-sectional structure of the substrate W before the process in step ST1a. FIG. 8B is a diagram showing an example of a cross-sectional structure of the substrate W after the process in step ST1a. FIGS. 8A and 8B are an example of trimming of a defective portion when the opening pattern of the tin-containing film 104 has a defect.

[0080] As shown in FIG. 8A, a defect in the opening pattern of the tin-containing film 104 is, for example, a residue DF that extends from a part of the side wall SS1 of the tin-containing film 104 toward the central portion of the opening OP or another part of the side wall SS1. As shown in FIG. 8B, this residue DF can be removed by trimming the side walls (side wall SS1 and side wall SS2) of the tin-containing film 104 in step ST1a. Since the defects in the opening pattern of the tin-containing film 104 are removed or suppressed, the defects in the opening pattern transferred to the intermediate film 103 in step ST2 and the defects in the opening pattern formed in the carbon-containing film 102 in step ST3 are also suppressed. Therefore, the dimensions and / or shape of the opening pattern of the carbon-containing film 102 can be made more uniform.

[0081] By trimming in step ST1a, the dimensions and / or shape of the opening pattern of the tin-containing film 104 change. For example, as shown in FIG. 8B, the dimension in the width direction of the opening OP after trimming becomes wider than before trimming. Therefore, the dimensions and / or shape of the opening pattern transferred to the intermediate film 103 in step ST2 also change. Here, as described above, in this processing method, in step ST3, the dimensions and / or shape of the opening pattern formed in the carbon-containing film 102 can be controlled. That is, this processing method can suppress the negative influence caused by trimming in step ST1a (for example, when the opening pattern of the tin-containing film 104 is a line-and-space (L / S) pattern, pattern collapse may occur in subsequent etching when the line width decreases).

[0082] Note that the trimming gas used in step ST1a may be included in the processing gas used for etching the intermediate film 103 in step ST2 so that the removal of the defects in the opening pattern of the tin-containing film 104 and the etching of the intermediate film 103 proceed simultaneously. Thereby, it is possible to suppress the transfer of the defects of the tin-containing film 104 to the opening pattern formed in the intermediate film 103.

[0083] FIG. 9 is a flowchart showing another example 2 of the present processing method. The example shown in FIG. 9 is different from the example shown in FIG. 3 in that after removing the tin-containing film 104 (step ST3a), the carbon-containing film 102 is etched (step ST3b) after step ST2.

[0084] First, in step ST3a, the tin-containing film 104 is removed. The removal of the tin-containing film 104 may be performed by etching the tin-containing film 104 using a plasma of a processing gas containing at least one selected from the group consisting of hydrogen, halogen, and carbon. The removal of the tin-containing gas may use a processing gas containing hydrogen or carbon, for example, H2, HBr, HCl, HI gas, CH4, CHF3, CO, etc. The removal of the tin-containing film 104 may use a processing gas containing halogen, for example, a gas containing no hydrogen such as Cl2 gas, Br2 gas, etc. When removing the tin-containing film 104, a bias RF signal or a bias DC signal may be supplied to the substrate support 11 to generate a bias potential between the plasma and the substrate W. Also, when removing the tin-containing film 104, it is not necessary to generate a bias potential between the plasma and the substrate W. In this case, the target temperature of the substrate W may be made higher than when generating a bias potential to promote the volatilization of reaction products (for example, tin halide). Note that the removal of the tin-containing film 104 may not use plasma. For example, the tin-containing film 104 may be removed by a chemical reaction with a gas of hydrogen halide. The hydrogen halide may be, for example, HBr, HCl, HI, etc. The processing gas used for removing the tin-containing film 104 may further contain an inert gas (Ar, N2, etc.).

[0085] Next, in step ST3b, the carbon-containing film 102 is etched. The etching of the carbon-containing film 102 may be performed using the plasma generated from the processing gas described in step ST3.

[0086] During the removal of the tin-containing film 104 in step ST3a, defects in the opening pattern of the intermediate film 103 can also be removed or reduced. Further, since the carbon-containing film 102 is etched after removing the tin-containing film 104, scattering of tin during the etching in step ST3b and adhesion of the tin to the substrate W can be suppressed. Thereby, defects in the opening pattern formed in the carbon-containing film 102 in step ST3b can be suppressed.

[0087] Next, an example of this processing method will be described. The present disclosure is not limited by the following examples at all.

[0088] <Example 1> A substrate W1 was prepared in a substrate processing apparatus 1 (step ST1). The substrate W1 has an SOC film, a SOG film, and a tin-containing film having an opening pattern laminated in this order on silicon. The opening pattern of the tin-containing film is a line and space (L / S) pattern. Next, the SOG film of the substrate W1 was etched (step ST2). Next, using O2, HBr, and He as a processing gas, the SOC film was etched (step ST3). The values obtained by dividing the measured values of line CD, space CD, LWR, and LER after each step by the measured values of line CD, space CD, LWR, and LER in the initial state (step ST1) are as shown in Table 1.

[0089]

Table 1

[0090] As shown in Table 1, the roughness (LWR and LER) of the opening pattern of the substrate W1 once increases by Step ST2 (etching of the SOG film) compared with the initial state, but becomes smaller by Step ST3 (etching of the SOC film) compared with the initial state. This is presumably because although the defects of the tin-containing film are transferred to the SOG film in Step ST2, in Step ST3, the SOC film can be etched while removing the defects of this SOG film. By this processing method, the roughness of the opening pattern formed on the substrate W1 could be improved and the uniformity could be enhanced.

[0091] <Example 2> A substrate W2 having the same configuration as that in Example 1 was prepared in the substrate processing apparatus 1 (Step ST1). Next, for the substrate W2, trimming of the tin-containing film was performed using HBr and Ar as the processing gases (Step ST1a). Next, etching of the SOG film (Step ST2) was performed using CF4. Next, etching of the SOC film (Step ST3) was performed using O2, HBr, and He as the processing gases. Here, the flow rate ratios of the processing gases O2, HBr, and He were performed in three patterns (hereinafter, referred to as Pattern 1, Pattern 2, and Pattern 3 in ascending order of the flow rate ratio of the HBr gas in the processing gases). The measured values of the line CD, space CD, LWR, and LER after each step were divided by the measured values of the line CD, space CD, LWR, and LER in the initial state (Step ST1), and the results are as shown in Table 2.

[0092]

Table 2

[0093] As shown in Table 2, the roughness (LWR and LER) of the opening pattern of the substrate W2 became smaller as it went through each of Steps ST1a (trimming of the tin-containing film), ST2 (etching of the SOG film), and ST3 (etching of the SOC film) of this processing method. By this processing method, the roughness of the opening pattern formed on the substrate W2 could be improved and the uniformity could be enhanced.

[0094] Also, as shown in Table 2, in step ST3 (etching of the SOC film), the size of line CD / space CD changed according to the composition ratio of the processing gas (flow rate ratio of O2, HBr, and He). This is presumably because the amount of the protective film formed on the sidewalls of the SOC film increased or decreased due to the change in the halogen (Br) content in the processing gas. By this processing method, the line CD and space CD of the aperture pattern formed on the substrate W2 could be controlled within a desired range.

[0095] <Reference Example> A substrate W3 having the same configuration as that in Example 1 was prepared in the substrate processing apparatus 1 (step ST1). Next, the tin-containing film was trimmed for the substrate W3 using HBr and Ar as the processing gas (step ST1a). Etching of the SOG film (step ST2) was performed. Next, etching of the SOC film was performed using N2 and H2 and using O2 and COS as the processing gas instead of the processing gas of this processing method. Pattern collapse was observed in the aperture pattern after the SOC film etching in any case.

[0096] Each of the above embodiments has been described for the purpose of explanation, and various modifications can be made without departing from the scope and spirit of the present disclosure. For example, this processing method can be executed using a substrate processing apparatus using an arbitrary plasma source such as an inductively coupled plasma or a microwave plasma in addition to the capacitively coupled substrate processing apparatus 1.

Description of Reference Numerals

[0097] 1... Substrate processing apparatus, 10... Plasma processing chamber, 10a... Side wall, 10e... Gas exhaust port, 10s... Plasma processing space, 11... Substrate support part, 11... Main body part, 111a... Central region, 111a... Central region, 111a... Substrate support surface, 111b... Annular region, 111b... Annular region, 112... Ring assembly, 13... Shower head, 13a... Gas supply port, 13b... Gas diffusion chamber, 13c... Gas inlet, 20... Gas supply part, 21... Gas source, 22... Flow controller, 30... Power supply, 31... RF power supply, 31a... First RF generation part, 31b... Second RF generation part, 32... DC power supply, 32a... First DC generation part, 32b... Second DC generation part, 40... Exhaust system, 50... Control part, 1, 50a... Computer, 50... Control part, 50a... Computer, 50a1... Processing part, 50a2... Memory part, 50a3... Communication interface, CT... Control part, LLM, LLM1... Load lock module, LM... Loader module, LP... Load port, PM... Substrate processing module, PS... Substrate processing system, W... Substrate, OP... Opening, PF... Protective film, SS, SS1... Side wall, DF... Residue, 101... Underlayer film, 102... Carbon-containing film, 103... Intermediate film, 104... Tin-containing film

Claims

1. A preparation step of preparing a substrate including a carbon-containing film, an intermediate film (excluding a metal-containing material film) provided on the carbon-containing film, and a tin-containing film provided on the intermediate film and having an opening pattern; A first etching step of etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film; A second etching step of removing the tin-containing film and etching the carbon-containing film using the intermediate film as a mask using plasma generated from a processing gas containing hydrogen, a halogen or carbon, and oxygen; A substrate processing method comprising:

2. The substrate processing method according to claim 1, wherein the intermediate film is a film in which an antireflection film is laminated on a SiON film.

3. The substrate processing method according to claim 1, wherein the intermediate film is a silicon-containing film.

4. Before the first etching step, the method further comprises a step of trimming at least sidewalls of the tin-containing film using plasma generated from a gas containing at least one selected from the group consisting of hydrogen, a halogen, and carbon. The substrate processing method according to claim 1.

5. The gas containing at least one selected from the group consisting of hydrogen, halogen, and carbon is H 2 gas, HBr gas, HCl gas, HI gas, CH 4 gas, CHF 3 gas, Cl 2 gas, CO gas, and Br 2 The substrate processing method according to claim 4, which is at least one gas selected from the group consisting of gas.

6. Before the first etching step, the method further comprises a step of trimming at least sidewalls of the tin-containing film using hydrogen halide. The substrate processing method according to claim 1.

7. The substrate processing method according to claim 6, wherein the hydrogen halide is at least one gas selected from the group consisting of HBr gas, HCl gas, and HI gas.

8. The substrate processing method according to any one of claims 1 to 7, wherein the tin-containing film is a photoresist film formed on the intermediate film.

9. The substrate prepared in the preparation step contains a residue extending toward the other part of the sidewall at a part of the sidewall of the tin-containing film. The substrate processing method according to any one of claims 1 to 8.

10. The substrate processing method according to any one of claims 1 to 9, wherein the processing gas includes a gas composed of molecules containing any one of Br, Cl, and I.

11. The process gas is CH 3 OH gas or CH 4 Gas and O 2 The substrate processing method according to claim 1 , further comprising a mixed gas of a gas and a gas.

12. The substrate processing method according to any one of claims 1 to 11, wherein the processing gas includes an inert gas.

13. A method for manufacturing a substrate, the method comprising: preparing a substrate including a carbon-containing film, an intermediate film provided on the carbon-containing film, and a tin-containing film provided on the intermediate film and having an opening pattern; a first etching step of etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film; a second etching step of removing the tin-containing film and etching the carbon-containing film using the intermediate film as a mask, using plasma generated from a processing gas containing hydrogen, a halogen or carbon, and oxygen; Equipped with The substrate processing method, wherein the intermediate film is a spin-on-glass (SOG) film, a SiON film, a SiC film, or a Si-containing anti-reflective coating (SiARC).

14. 14. The substrate processing method according to claim 1, wherein the carbon-containing film is a spin-on carbon (SOC) film or an amorphous carbon film (ACL).

15. 15. The substrate processing method according to claim 1, wherein the carbon-containing film is formed on an underlayer film, and further comprising, after the second etching step, a third etching step of etching the underlayer film using the carbon-containing film as a mask.

16. a preparation step of preparing a substrate including a carbon-containing film, an intermediate film (excluding a metal-containing material film) provided on the carbon-containing film, and a tin-containing film having an opening pattern provided on the intermediate film; a first etching step of etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film; removing the tin-containing film; a second etching step of etching the carbon-containing film using the intermediate film as a mask with plasma generated from a process gas containing hydrogen, a halogen or carbon, and oxygen; A substrate processing method comprising:

17. 17. The substrate processing method according to claim 16, wherein the step of removing the tin-containing film includes etching the tin-containing film using plasma generated from a gas containing at least one selected from the group consisting of hydrogen, halogen, and carbon.

18. The gas containing at least one selected from the group consisting of hydrogen, halogen, and carbon is H 2 gas, HBr gas, HCl gas, HI gas, CH 4 gas, CHF 3 gas, Cl 2 gas, CO gas, and Br 2 gas, and is at least one gas selected from the group consisting of the substrate processing method according to claim 17.

19. 17. The substrate processing method of claim 16, wherein the step of removing the tin-containing film includes removing the tin-containing film using a hydrogen halide.

20. 20. The substrate processing method according to claim 19, wherein the hydrogen halide is at least one gas selected from the group consisting of HBr gas, HCl gas, and HI gas.

21. a plasma processing chamber; a gas supply unit that supplies a processing gas to the plasma processing chamber; a power supply that supplies power to generate plasma in the plasma processing chamber; and a control unit; The control unit placing a substrate in the plasma processing chamber, the substrate including: a carbon-containing film; an intermediate film (excluding a metal-containing material film) provided on the carbon-containing film; and a tin-containing film provided on the intermediate film and having an opening pattern; Etching the intermediate film using the tin-containing film as a mask to transfer the opening pattern to the intermediate film; A process gas containing hydrogen, a halogen or carbon, and oxygen is supplied to the plasma processing chamber from the gas supply unit, and plasma is generated in the plasma processing chamber by applying power from the power source, thereby removing the tin-containing film and etching the carbon-containing film using the intermediate film as a mask. Substrate processing equipment.

Images