WO2024043139A1 - Procédé de gravure et appareil de traitement au plasma - Google Patents

Procédé de gravure et appareil de traitement au plasma Download PDF

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Publication number
WO2024043139A1
WO2024043139A1 PCT/JP2023/029468 JP2023029468W WO2024043139A1 WO 2024043139 A1 WO2024043139 A1 WO 2024043139A1 JP 2023029468 W JP2023029468 W JP 2023029468W WO 2024043139 A1 WO2024043139 A1 WO 2024043139A1
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WIPO (PCT)
Prior art keywords
film
gas
recess
processing gas
plasma
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PCT/JP2023/029468
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English (en)
Japanese (ja)
Inventor
隆幸 勝沼
高寛 大堀
壮一郎 木村
翔 熊倉
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東京エレクトロン株式会社
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Publication of WO2024043139A1 publication Critical patent/WO2024043139A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/3065—Plasma etching; Reactive-ion etching
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy

Definitions

  • the exemplary embodiments of the present disclosure relate to an etching method and a plasma processing apparatus.
  • tungsten silicide WSi
  • the present disclosure provides a technique for etching a film while suppressing abnormalities in the shape of the sidewalls of recesses.
  • an etching method includes (a) providing a substrate, the substrate comprising a first film having a recess and a second film on the first film; a first film containing a metal element and a non-metallic element, and the second film having an opening corresponding to the recess; (c) after the step (b), etching the recess through the opening with a second plasma generated from a second processing gas different from the first processing gas;
  • the second processing gas includes a halogen-containing gas.
  • a technique for etching a film while suppressing irregularities in the sidewalls of recesses.
  • FIG. 1 is a diagram schematically illustrating a plasma processing apparatus according to one exemplary embodiment.
  • FIG. 2 is a diagram schematically illustrating a plasma processing apparatus according to one exemplary embodiment.
  • FIG. 3 is a flowchart of an etching method according to one exemplary embodiment.
  • FIG. 4 is a cross-sectional view of an example substrate to which the method of FIG. 3 may be applied.
  • FIG. 5 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 6 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 7 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 1 is a diagram schematically illustrating a plasma processing apparatus according to one exemplary embodiment.
  • FIG. 2 is a diagram schematically illustrating a plasma processing apparatus according to one exemplary embodiment.
  • FIG. 3 is a flowchar
  • FIG. 8 is an example of a timing chart showing temporal changes in source power and bias power.
  • FIG. 9 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 10 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 11 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 12 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 13 is a flowchart of an etching method according to one exemplary embodiment.
  • FIG. 14 is a cross-sectional view of an example substrate to which the method of FIG. 13 may be applied.
  • FIG. 14 is a cross-sectional view of an example substrate to which the method of FIG. 13 may be applied.
  • FIG. 15 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 16 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 17 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • FIG. 1 is a diagram for explaining a configuration example of a plasma processing system.
  • a plasma processing system includes a plasma processing apparatus 1 and a controller 2.
  • the plasma processing system is an example of a substrate processing system
  • the plasma processing apparatus 1 is an example of a substrate processing apparatus.
  • the plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support section 11, and a plasma generation section 12.
  • the plasma processing chamber 10 has a plasma processing space.
  • the plasma processing chamber 10 also includes at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas exhaust port for discharging gas from the plasma processing space.
  • the gas supply port is connected to a gas supply section 20, which will be described later, and the gas discharge port is connected to an exhaust system 40, which will be described later.
  • the substrate support section 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.
  • the plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space.
  • the plasmas formed in the plasma processing space are capacitively coupled plasma (CCP), inductively coupled plasma (ICP), and ECR plasma (Electron-Cyclotron-resonance plasma).
  • CCP capacitively coupled plasma
  • ICP inductively coupled plasma
  • ECR plasma Electro-Cyclotron-resonance plasma
  • HWP Helicon Wave Plasma
  • SWP surface wave plasma
  • various types of plasma generation units may be used, including an AC (Alternating Current) plasma generation unit and a DC (Direct Current) plasma generation unit.
  • the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes an RF (Radio Frequency) signal and a microwave signal.
  • the RF signal has a frequency within the range of 100kHz to 150MHz.
  • the control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various steps described in this disclosure.
  • the control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various steps 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 is realized by, for example, a computer 2a.
  • the processing unit two a1 may be configured to read a program from the storage unit two a2 and perform various control operations by executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary.
  • the acquired program is stored in the storage unit 2a2, and is read out from the storage unit 2a2 and executed by the processing unit 2a1.
  • the medium may be various storage media readable by the computer 2a, or may be 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 RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. Good.
  • the communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).
  • FIG. 2 is a diagram for explaining a configuration example of an inductively coupled plasma processing apparatus.
  • the inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply section 20, a power supply 30, and an exhaust system 40.
  • Plasma processing chamber 10 includes a dielectric window 101 .
  • the plasma processing apparatus 1 includes a substrate support section 11, a gas introduction section, and an antenna 14.
  • Substrate support 11 is arranged within plasma processing chamber 10 .
  • Antenna 14 is disposed on or above plasma processing chamber 10 (ie, on or above dielectric window 101).
  • the plasma processing chamber 10 has a plasma processing space 10s defined by a dielectric window 101, a side wall 102 of the plasma processing chamber 10, and a substrate support 11. Plasma processing chamber 10 is grounded.
  • the substrate support section 11 includes a main body section 111 and a ring assembly 112.
  • the main body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112.
  • a wafer is an example of a substrate W.
  • the annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in plan view.
  • the substrate W is placed on the central region 111a of the main body 111, and the ring assembly 112 is placed 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.
  • the main body 111 includes a base 1110 and an electrostatic chuck 1111.
  • Base 1110 includes a conductive member.
  • the conductive member of base 1110 can function as a bias electrode.
  • Electrostatic chuck 1111 is placed on base 1110.
  • Electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within ceramic member 1111a.
  • Ceramic member 1111a has a central region 111a. In one embodiment, ceramic member 1111a also has an annular region 111b. Note that another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b.
  • ring assembly 112 may be placed on the annular electrostatic chuck or the annular insulation member, or may be placed on both the electrostatic chuck 1111 and the annular insulation member.
  • at least one RF/DC electrode coupled to an RF power source 31 and/or a DC power source 32, which will be described later, may be disposed within the ceramic member 1111a.
  • at least one RF/DC electrode functions as a bias electrode.
  • the conductive member of the base 1110 and at least one RF/DC electrode may function as a plurality of bias electrodes.
  • the electrostatic electrode 1111b may function as a bias electrode.
  • the substrate support 11 includes at least one bias electrode.
  • Ring assembly 112 includes one or more annular members.
  • the one or more annular members include one or more edge rings and at least one cover ring.
  • the edge ring is made of a conductive or insulating material
  • the cover ring is made of an insulating material.
  • the substrate support unit 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature.
  • the temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof.
  • a heat transfer fluid such as brine or gas flows through the flow path 1110a.
  • a channel 1110a is formed within the base 1110 and one or more heaters are disposed within the ceramic member 1111a of the electrostatic chuck 1111.
  • the substrate support section 11 may include a heat transfer gas supply section configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.
  • the gas introduction section is configured to introduce at least one processing gas from the gas supply section 20 into the plasma processing space 10s.
  • the gas inlet includes a Center Gas Injector (CGI) 13 .
  • the central gas injection part 13 is disposed above the substrate support part 11 and attached to the central opening formed in the dielectric window 101.
  • the central gas injection part 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas introduction port 13c.
  • the processing gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas introduction port 13c.
  • the gas introduction part includes one or more side gas injectors (SGI) attached to one or more openings formed in the side wall 102. May include.
  • SGI side gas injectors
  • the gas supply section 20 may include at least one gas source 21 and at least one flow rate controller 22.
  • the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 via a respective flow controller 22 to the gas inlet.
  • Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller.
  • gas supply 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one process gas.
  • Power supply 30 includes an RF power supply 31 coupled to plasma processing chamber 10 via at least one impedance matching circuit.
  • RF power supply 31 is configured to provide at least one RF signal (RF power) to at least one bias electrode and antenna 14 .
  • RF power supply 31 can function as at least a part of the plasma generation section 12. Further, by supplying a bias RF signal to at least one bias electrode, a bias potential is generated on the substrate W, and ions in the formed plasma can be drawn into the substrate W.
  • the RF power supply 31 includes a first RF generation section 31a and a second RF generation section 31b.
  • the first RF generation section 31a is coupled to the antenna 14 via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation.
  • the source RF signal has a frequency within the range of 10 MHz to 150 MHz.
  • the first RF generator 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are provided to antenna 14.
  • the second RF generation section 31b is coupled to at least one bias 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 or different than the frequency of the source RF signal.
  • the bias RF signal has a lower frequency than the frequency of the source RF signal.
  • the bias RF signal has a frequency within the range of 100kHz to 60MHz.
  • the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies.
  • the generated one or more bias RF signals are provided to at least one bias electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.
  • Power source 30 may also include a DC power source 32 coupled to plasma processing chamber 10 .
  • the DC power supply 32 includes a bias DC generation section 32a.
  • bias DC generator 32a is connected to at least one bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to at least one bias electrode.
  • the bias DC signal may be pulsed.
  • a sequence of voltage pulses is applied to at least one bias electrode.
  • the voltage pulse may have a pulse waveform that is rectangular, trapezoidal, triangular, or a combination thereof.
  • a waveform generator for generating a sequence of voltage pulses from a DC signal is connected between the bias DC generator 32a and the at least one bias electrode. Therefore, the bias DC generation section 32a and the waveform generation section constitute a voltage pulse generation section.
  • the voltage pulse may have positive polarity or negative polarity.
  • the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle.
  • the bias DC generation section 32a may be provided in addition to the RF power source 31, or may be provided in place of the second RF generation section 31b.
  • the antenna 14 includes one or more coils.
  • antenna 14 may include an outer coil and an inner coil that are coaxially arranged.
  • the RF power source 31 may be connected to both the outer coil and the inner coil, or may be connected to either one of the outer coil and the inner coil.
  • the same RF generator may be connected to both the outer coil and the inner coil, or separate RF generators may be separately connected to the outer coil and the inner coil.
  • the exhaust system 40 may be connected to a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10, for example.
  • Evacuation 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 turbomolecular pump, a dry pump, or a combination thereof.
  • FIG. 3 is a flowchart of an etching method according to one exemplary embodiment.
  • Etching method MT1 (hereinafter referred to as "method MT1") shown in FIG. 3 can be performed by the plasma processing apparatus 1 of the above embodiment.
  • Method MT1 may be applied to substrate W.
  • FIG. 4 is a cross-sectional view of an example substrate to which the method of FIG. 3 can be applied.
  • the substrate W includes a first film F1 and a second film F2 on the first film F1.
  • the substrate W may further include a third film F3 under the first film F1.
  • the substrate W may further include a base region UR under the third film F3.
  • the first film F1 includes a metal element and a nonmetal element.
  • the first film F1 may include, as a metal element, at least one transition metal element selected from the group consisting of tungsten, titanium, molybdenum, hafnium, zirconium, and ruthenium.
  • the first film F1 may contain at least one of silicon, carbon, nitrogen, oxygen, hydrogen, boron, and phosphorus as a nonmetallic element.
  • the first film F1 is made of tungsten silicide (W x Si y ), tungsten silicon nitride (W x Si y N z ), tungsten silicon boron (W x Si y B z ), and tungsten silicon carbon (W x Si y C z ) . ) may also contain at least one tungsten compound selected from the group consisting of: Each of the composition ratios x, y, and z may be a real number larger than 0.
  • the first film F1 may be a film for forming a hard mask.
  • the second film F2 has an opening OP.
  • the second film F2 may have a plurality of openings OP.
  • the opening OP may have a hole pattern or a line pattern.
  • the dimension (CD) of the opening OP may be 30 nm or less.
  • the second film F2 may be a mask.
  • the second film F2 may include at least one of a silicon-containing film, a carbon-containing film, and a metal-containing film.
  • the second film F2 may be a silicon oxide film.
  • the second film F2 may be a resist mask.
  • the second film F2 may be a photoresist mask containing tin.
  • the second film F2 may be a resist mask for EUV exposure.
  • the second film F2 may be a zirconium-containing film or a zirconium oxide-containing film.
  • the second film F2 may have a dense and dense pattern.
  • the second film F2 may include a plurality of first openings OP arranged at a first pitch and having a first dimension, and a plurality of second openings OP arranged at a second pitch and having a second dimension.
  • the second pitch is different from the first pitch.
  • the second dimension is different from the first dimension.
  • “Dimensions” here means the diameter of the circle (diameter across) when the opening is circular, and means at least one of the major axis and minor axis of the ellipse when the opening is oval. .
  • the first dimension and the second dimension are compared by comparing the major axes or the minor axes.
  • the second film F2 may be formed by pattern reversal. For example, a fourth film is formed on the first film F1, and the fourth film is patterned by photolithography and etching. After that, a fifth film is formed on the patterned fourth film, and the opening in the fourth film is filled with the fifth film. Thereafter, by removing the patterned fourth film by lift-off, the remaining fifth film becomes the second film F2.
  • the pattern reversal technique is described, for example, in a Japanese patent application (Japanese Patent Application No. 2021-173638) filed on October 25, 2021. The entirety of Japanese Patent Application No. 2021-173638 is incorporated herein by reference.
  • the third film F3 may be a silicon-containing film or a nitride film.
  • the silicon-containing film may be a silicon nitride film (SiN film) or a silicon carbonitride film (SiCN film).
  • the third film F3 may be an etching stop layer.
  • the underlying region UR may include at least one film for a memory device such as a DRAM or 3D-NAND.
  • FIGS. 5-7 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • the method MT1 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 by the control section 2.
  • a substrate W on a substrate support 11 disposed within a plasma processing chamber 10 is processed.
  • method MT1 may include steps ST1 to ST6. Steps ST1 to ST6 may be performed in order. Steps ST1 to ST6 may be performed in-situ or in-system. When steps ST1 to ST6 are performed in-system, the chamber where step ST5 is performed may be different from the chamber where step ST4 is performed. Method MT1 may not include at least one of step ST1, step ST2, and step ST6. Step ST1 may be performed after step ST6.
  • step ST1 the plasma processing chamber 10 is cleaned.
  • a cleaning gas may be used in step ST1.
  • the cleaning gas may contain fluorine, chlorine or oxygen.
  • step ST2 the inner wall of the plasma processing chamber 10 is precoated.
  • a precoat gas may be used in step ST2.
  • the precoat gas may include at least one of silicon tetrachloride (SiCl 4 ) gas and aminosilane-based gas.
  • a substrate W shown in FIG. 5 is provided.
  • the first film F1 of the substrate W has a recess RS.
  • the recessed portion RS corresponds to the opening OP of the second film F2.
  • Substrate W may be placed within plasma processing chamber 10 .
  • the substrate W may be supported within the plasma processing chamber 10 by a substrate support 11 .
  • the underlying region UR may be arranged between the substrate support section 11 and the third film F3.
  • the recess RS may be formed by etching the first film F1 through the opening OP in the substrate W of FIG. 4. Etching may be performed similarly to step ST5.
  • the recess RS may be provided in the first film F1 in advance before the substrate W is supplied into the plasma processing chamber 10.
  • a protective film DP is formed on the side wall RSa of the recess RS using the first plasma PL1 generated from the first processing gas.
  • the protective film DP may not be formed on the bottom RSb of the recess RS, or may be formed on the bottom RSb of the recess RS.
  • the protective film DP may be formed on the second film F2.
  • the protective film DP may be formed by CVD.
  • step ST4 by increasing the pressure or adjusting the temperature, the thickness of the protective film DP on the side wall RSa of the recess RS can be made larger than the thickness of the protective film DP on the bottom RSb of the recess RS.
  • the first processing gas in step ST4 may include at least one of a silicon-containing gas, a carbon-containing gas, a boron-containing gas, a phosphorus-containing gas, a metal-containing gas, a sulfur-containing gas, a bromine-containing gas, and an iodine-containing gas.
  • silicon-containing gases include SiCl4 gas and SiF4 gas.
  • carbon-containing gases include fluorocarbon gases, hydrofluorocarbon gases, and hydrocarbon gases.
  • boron-containing gases include BCl3 gas.
  • Examples of phosphorus-containing gases include PF x gas.
  • metal-containing gases include WF6 gas and TiCl4 gas.
  • sulfur-containing gases include SO2 gas and COS gas.
  • the protective film DP may contain at least one of silicon, carbon, oxygen, boron, phosphorus, metal, sulfur, bromine, and iodine.
  • the first example of the processing gas in step ST4 includes HBr gas.
  • the processing gas of the first example may further contain oxygen gas.
  • the protective film DP includes SiBr x O y .
  • the processing gas of the second example in step ST4 contains SiCl 4 gas and oxygen gas.
  • the protective film DP contains SiO x .
  • the processing gas of the third example in step ST4 includes BCl 3 gas and oxygen gas.
  • the protective film DP contains BOx .
  • the processing gas of the fourth example in step ST4 contains C 4 F 8 gas or C 4 F 6 gas.
  • the protective film DP includes C x F y .
  • the processing gas of the fifth example in step ST4 contains CH 3 F gas or CH 4 gas.
  • the protective film DP includes C x H y .
  • the processing gas of the sixth example in step ST4 includes COS gas or CH x F y gas.
  • the processing time of step ST4 may be 5 to 300 seconds.
  • step ST5 In step ST5, as shown in FIG. 7, the recessed portion RS of the first film F1 is etched through the opening OP by the second plasma PL2 generated from the second processing gas.
  • the plasma processing chamber in which step ST5 is performed may be the same as or different from the plasma processing chamber in which step ST4 is performed.
  • the second processing gas in step ST5 is different from the first processing gas in step ST4.
  • the second processing gas includes a halogen-containing gas.
  • halogen-containing gases include chlorine gas.
  • the second processing gas may further include a silicon-containing gas and an oxygen-containing gas.
  • silicon-containing gases include SiCl4 gas.
  • oxygen-containing gases include oxygen gas.
  • the second processing gas may further include a fluorine-containing gas.
  • fluorine-containing gases include fluorocarbon gases, hydrofluorocarbon gases, and NF3 gases.
  • the second processing gas may further include a noble gas.
  • the processing time of step ST5 may be shorter than the processing time of step ST4.
  • the processing time of step ST5 may be 1 to 50 seconds.
  • step ST6 step ST6
  • step ST4 and step ST5 are repeated.
  • the thickness of the protective film DP may be 25% or less of the dimension of the recessed portion RS.
  • the thickness of the protective film DP may be 5 nm or less.
  • the protective film DP may be removed using diluted hydrofluoric acid (DHF), for example.
  • DHF diluted hydrofluoric acid
  • FIG. 8 is an example of a timing chart showing temporal changes in source power and bias power.
  • This timing chart is related to step ST5.
  • the second plasma PL2 may be generated by supplying source power (second high frequency power).
  • bias power may be supplied to the substrate support section 11.
  • the source power may be high frequency power HF provided to the antenna 14 of FIG.
  • the bias power may be high frequency power LF applied to the bias electrode in the main body part 111 of the substrate support part 11.
  • High frequency power HF has a higher frequency than the frequency of high frequency power LF.
  • a continuous wave (CW) of source power and a continuous wave of bias power may be supplied, or a pulse of source power and a pulse of bias power may be supplied.
  • the pulses may be generated by switching the power on and off, or may be generated depending on the magnitude of the power value.
  • pulses of source power and bias power may be supplied in step ST5.
  • the source power and bias power may be applied periodically with a period CY.
  • the period CY may be 0.1 to 100 milliseconds.
  • the phase of the beginning of the pulse of source power may be synchronized with the phase of the beginning of the pulse of bias power.
  • the duty ratio of the pulses of source power may be greater than the duty ratio of the pulses of bias power. Duty ratio means the ratio of pulse width to period.
  • the period CY may include a first period PA1 and a second period PB1.
  • the second period PB1 is a period after the first period PA1. In the first period PA1, the source power may be maintained at high power H2. In the second period PB1, the source power may be maintained at low power L2.
  • the duty ratio of the source power pulse is the ratio of the first period PA1 to the period CY.
  • the cycle CY may include a third period PA2 and a fourth period PB2.
  • the fourth period PB2 is a period after the third period PA2.
  • the third period PA2 is shorter than the first period PA1.
  • the fourth period PB2 is longer than the second period PB1.
  • the bias power may be maintained at high power H1.
  • the bias power may be maintained at low power L1.
  • the duty ratio of the bias power pulse is the ratio of the third period PA2 to the period CY.
  • the first plasma PL1 may be generated by supplying source power (first high frequency power).
  • source power first high frequency power
  • bias power may not be supplied.
  • a pulse of source power may be supplied, or a continuous wave of source power may be supplied.
  • the protective film DP suppresses etching of the side wall RSa of the recess RS of the first film F1. Therefore, the first film F1 can be etched while suppressing the abnormal shape (bowing) of the side wall RSa of the recess RS. Furthermore, the value (3 ⁇ ) of LCDU (Local CD Uniformity) at the bottom RSb of the recess RS can also be reduced.
  • the value of LCDU is an index indicating the dimensional uniformity at the bottom RSb of the recess RS. A decrease in the value of LCDU means an increase in dimensional uniformity.
  • the protective film DP on the second film F2 suppresses etching of the second film F2. Therefore, the etching selectivity of the first film F1 to the second film F2 can be improved.
  • step ST5 contains a silicon-containing gas and an oxygen-containing gas
  • silicon oxide is deposited on the second film F2 so the etching selectivity of the first film F1 to the second film F2 can be improved.
  • the second processing gas in step ST5 contains a fluorine-containing gas
  • chemical species derived from the fluorine-containing gas can suppress clogging of the recess RS by deposits (for example, silicon oxide).
  • FIG. 9 is a flowchart of an etching method according to one exemplary embodiment.
  • Etching method MT2 (hereinafter referred to as "method MT2") shown in FIG. 9 can be executed by the plasma processing apparatus 1 of the above embodiment.
  • Method MT2 may be applied to the substrate W of FIG. 4.
  • FIGS. 10-12 are cross-sectional views illustrating a step in an etching method according to one exemplary embodiment.
  • the method MT2 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 by the control section 2.
  • a substrate W on a substrate support 11 disposed within a plasma processing chamber 10 is processed.
  • method MT2 may be the same as method MT1 except that it includes step ST41 and step ST42 instead of step ST4.
  • Process ST42 may be performed between process ST41 and process ST5, or may be performed between process ST3 and process ST41.
  • the steps of method MT2 may be performed in-situ or in-system.
  • the chamber in which step ST5 is performed may be different from the chamber in which step ST41 or step ST42 is performed.
  • Method MT2 may not include at least one of step ST1, step ST2, and step ST6. Step ST1 may be performed after step ST6.
  • step ST41 the side wall RSa of the recess RS is modified by the first plasma PL1 generated from the first processing gas.
  • the bottom portion RSb of the recessed portion RS may be modified by the first plasma PL1.
  • the first processing gas includes an oxygen-containing gas. Examples of oxygen-containing gases include oxygen (O 2 ) gas.
  • a modified layer ML is formed within the sidewall RSa.
  • the modified layer ML may be formed on the bottom RSb.
  • the modified layer ML may be an oxidized layer obtained by oxidizing the first film F1.
  • the modified layer ML may contain an oxide of a nonmetallic element contained in the first film F1.
  • the processing time of step ST41 may be 3 to 20 seconds.
  • a deposit DP1 is deposited on the second film F2 by the third plasma PL3 generated from the third processing gas.
  • the deposit DP1 may be deposited on the upper surface of the second film F2.
  • the deposit DP1 may be deposited on the side wall of the second film F2 that defines the opening OP, or may be deposited on the side wall RSa of the recess RS.
  • the thickness of the deposit DP1 may be 20 nm or less.
  • the third processing gas in step ST42 is different from the first processing gas and the second processing gas.
  • the third processing gas may include a silicon-containing gas and an oxygen-containing gas. Examples of silicon-containing gases include SiCl4 gas and SiF4 gas. Examples of oxygen-containing gases include oxygen gas.
  • the third processing gas may further include a noble gas. Examples of noble gases include helium gas.
  • the protective film DP may be a silicon oxide film.
  • third plasma PL3 may be generated by supplying source power (third high frequency power).
  • source power third high frequency power
  • bias power may not be supplied.
  • a pulse of source power may be supplied, or a continuous wave of source power may be supplied.
  • the processing time of step ST42 may be shorter than the processing time of step ST41.
  • the processing time of step ST42 may be more than 0 seconds and less than 5 seconds. By shortening the processing time of step ST42, it is possible to suppress clogging of the opening OP by the deposit DP1.
  • step ST5 As shown in FIG. 12, the recessed portion RS of the first film F1 is etched by the second plasma PL2 generated from the second processing gas through the opening OP.
  • the temperature of the substrate support portion 11 may be 60°C or higher, 80°C or higher, or 100°C or higher.
  • step ST5 etching of the sidewall RSa of the recessed portion RS of the first film F1 is suppressed by the modified layer ML. Therefore, the first film F1 can be etched while suppressing the abnormal shape (bowing) of the side wall RSa of the recess RS. Furthermore, the value of LCDU at the bottom RSb of the recess RS can also be reduced. Furthermore, the deposit DP1 on the second film F2 suppresses etching of the second film F2. Therefore, the etching selectivity of the first film F1 to the second film F2 can be improved.
  • FIG. 13 is a flowchart of an etching method according to one exemplary embodiment.
  • Etching method MT3 (hereinafter referred to as "method MT3") shown in FIG. 13 can be performed by the plasma processing apparatus 1 of the above embodiment.
  • Method MT3 may be applied to substrate W.
  • FIG. 14 is a cross-sectional view of an example substrate to which method MT3 of FIG. 13 can be applied.
  • the substrate W in FIG. 14 has the same configuration as the substrate W in FIG. 4 except that the opening OP includes an opening OP1 and an opening OP2.
  • the dimensions of the opening OP2 are larger than the dimensions of the opening OP1.
  • FIGS. 15-17 is a cross-sectional view illustrating a step in an etching method according to one exemplary embodiment.
  • the method MT3 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 by the control section 2.
  • the substrate W on the substrate support 11 disposed within the plasma processing chamber 10 is processed.
  • method MT3 may be the same as method MT1 except that it includes step ST41 instead of step ST4.
  • the steps of method MT3 may be performed in-situ or in-system.
  • the chamber in which step ST5 is performed may be different from the chamber in which step ST41 is performed.
  • Method MT3 may not include at least one of step ST1, step ST2, and step ST6.
  • Step ST1 may be performed after step ST6.
  • a substrate W shown in FIG. 15 is provided.
  • the first film F1 of the substrate W has a recess RS1 and a recess RS2.
  • the recess RS1 corresponds to the opening OP1 of the second film F2.
  • the recessed portion RS1 has a side wall RS1a and a bottom portion RS1b.
  • the recess RS2 corresponds to the opening OP2 of the second film F2.
  • the recess RS2 has a side wall RS2a and a bottom RS2b.
  • the recess RS1 and the recess RS2 may be formed by etching the first film F1 through the opening OP1 and the opening OP2 in the substrate W of FIG. 14. Etching may be performed similarly to step ST5.
  • the recess RS1 and the recess RS2 may be provided in the first film F1 in advance before the substrate W is supplied into the plasma processing chamber 10.
  • step ST41 In step ST41, as shown in FIG. 16, the side wall RS1a of the recess RS1 and the side wall RS2a of the recess RS2 are modified by the first plasma PL1 generated from the first processing gas.
  • the first processing gas includes an oxygen-containing gas.
  • a modified layer ML is formed within the side wall RS1a and the side wall RS2a.
  • step ST5 In step ST5, as shown in FIG. 17, the recess RS1 and the recess RS2 of the first film F1 are etched by the second plasma PL2 generated from the second processing gas through the opening OP1 and the opening OP2.
  • the second processing gas in step ST5 is different from the first processing gas in step ST41.
  • the second processing gas includes a halogen-containing gas and an additive gas.
  • halogen-containing gases include chlorine (Cl 2 ) gas and hydrogen bromide (HBr) gas.
  • the additive gas includes at least one of an oxygen-containing gas, a nitrogen-containing gas, and a sulfur-containing gas.
  • oxygen-containing gases include oxygen ( O2 ) gas, carbon monoxide (CO) gas, and carbon dioxide ( CO2 ) gas.
  • nitrogen-containing gases include nitrogen ( N2 ) gas.
  • sulfur-containing gases include carbonyl sulfide (COS) gas, sulfur dioxide (SO 2 ) gas, and hydrogen sulfide (H 2 S) gas.
  • the product BP generated by etching may adhere to the side wall RS1a of the recess RS1 and the side wall RS2a of the recess RS2.
  • the product BP contains an oxide such as a silicon oxide or a metal oxide.
  • the product BP contains, for example, SiCl x O y or WCl x O y (x and y each being a natural number).
  • the product BP contains a nitrogen-containing gas
  • the product BP contains a nitride such as silicon nitride or metal nitride.
  • the product BP contains sulfide such as silicon sulfide or metal sulfide.
  • the dimension TCD2 at the upper end of the recess RS2 is larger than the dimension TCD1 at the upper end of the recess RS1.
  • the thickness of the product BP increases from the upper end of the recess RS1 toward the bottom RS1b.
  • the dimension BCD1 at the bottom portion RS1b of the recessed portion RS1 becomes smaller.
  • the thickness of the product BP increases from the top of the recess RS2 toward the bottom RS2b.
  • the dimension BCD2 at the bottom RS2b of the recess RS2 becomes smaller.
  • the difference between dimension BCD2 and dimension BCD1 is smaller than the difference between dimension TCD2 and dimension TCD1. Therefore, the value of LCDU at the bottom RS1b of the recess RS1 and the bottom RS2b of the recess RS2 can be reduced.
  • step ST6 step ST41 and step ST5 are repeated.
  • the flow rate ratio of the additive gas to the total flow rate of the second processing gas in step ST5 of step ST6 may be different from the flow rate ratio of the additive gas to the total flow rate of the second processing gas in step ST5 before step ST6.
  • the flow rate ratio of the additive gas to the total flow rate of the second processing gas may be changed in step ST5 for each cycle including step ST41 and step ST5. For example, as the depths of the recesses RS1 and RS2 become deeper, the flow rate ratio of the additive gas to the total flow rate of the second processing gas may be increased or decreased in step ST5. Increasing the flow rate ratio of the additive gas increases the amount of product BP produced by etching.
  • step ST5 etching of the sidewall RS1a of the recess RS1 and the sidewall RS2a of the recess RS2 of the first film F1 is suppressed by the modified layer ML and the product BP. Therefore, the first film F1 can be etched while suppressing shape abnormalities (bowing) of the side wall RS1a of the recess RS1 and the side wall RS2a of the recess RS2.
  • a substrate having a WSi film and a mask on the WSi film was prepared.
  • the mask is a silicon oxide film with an opening.
  • steps ST3 to ST6 of method MT1 were performed to etch the WSi film.
  • the WSi film was etched to form a recess.
  • a protective film was formed on the side wall of the recess using the first plasma generated from the first processing gas.
  • the first processing gas includes fluorocarbon gas.
  • the recessed portions were etched using second plasma generated from the second processing gas.
  • the second processing gas includes chlorine gas, fluorocarbon gas, SiCl4 gas, and oxygen gas.
  • the etching selectivity of the WSi film to the mask was calculated by measuring the thickness of the mask in the cross section of the substrate.
  • the thickness of the mask after performing method MT1 was greater than the thickness of the mask before performing method MT1.
  • the etching selectivity in the second experiment was 13.6. Therefore, it can be seen that the etching selectivity is improved in the first experiment compared to the second experiment.
  • Step ST3 a substrate having a WSi film and a mask on the WSi film was prepared.
  • the mask is a silicon oxide film with an opening.
  • Step ST3, Step ST41, Step ST42, Step ST5, and Step ST6 of method MT2 were performed to etch the WSi film.
  • the WSi film was etched to form a recess.
  • step ST41 the sidewalls of the recesses were oxidized by first plasma generated from a first processing gas containing oxygen gas.
  • the processing time of step ST41 was 4.5 seconds.
  • step ST42 a silicon oxide film (deposit) was deposited on the upper surface of the mask using a third plasma generated from a third processing gas containing SiCl 4 gas, oxygen gas, and helium gas.
  • the processing time of step ST42 was 1 second.
  • step ST5 the recessed portions were etched using second plasma generated from the second processing gas.
  • the maximum dimension of the recess formed in the WSi film was measured.
  • the bowing dimension was 13.9 nm.
  • the bowing dimension was 14.6 nm. Therefore, it can be seen that bowing is suppressed by performing step ST42.
  • the maximum dimension of the recess formed in the WSi film was measured.
  • the bowing dimension was 15.9 nm.
  • the bowing dimension was 13.2 nm. Therefore, it can be seen that the bowing dimension can be reduced by lengthening the processing time of step ST41.
  • the third experiment and the fifth experiment no major changes were observed in the shape of the recesses formed in the WSi film. Therefore, it can be seen that even if the processing time of step ST41 is shortened, the influence on the shape of the recessed portion is small.
  • Step ST3 a substrate having a WSi film and a mask on the WSi film was prepared.
  • the mask is a silicon oxide film having hole pattern openings.
  • Step ST3, Step ST41, Step ST5, and Step ST6 of method MT3 were performed to etch the WSi film.
  • the WSi film was etched to form a recess.
  • step ST41 the sidewalls of the recesses were oxidized by first plasma generated from a first processing gas containing oxygen gas.
  • step ST5 the recessed portions were etched using second plasma generated from a second processing gas containing chlorine gas and oxygen gas.
  • [E1] (a) A step of providing a substrate, the substrate comprising a first film having a recess and a second film on the first film, the first film containing a metal element and a non-metal element. , the second film has an opening corresponding to the recess; (b) forming a protective film on the sidewall of the recess by a first plasma generated from a first processing gas; (c) After the step (b), the recess is etched through the opening with a second plasma generated from a second processing gas different from the first processing gas, and the recess is etched using the second processing gas. includes a halogen-containing gas; Including etching methods.
  • the protective film suppresses etching of the sidewall of the recess of the first film. Therefore, the first film can be etched while suppressing abnormalities in the shape of the side walls of the recess.
  • the first plasma is generated by supplying a first high frequency power
  • the recessed portion is etched by supplying second high frequency power and bias power, and the bias power is supplied to a substrate support portion for supporting the substrate, [E1] or [ E2].
  • chemical species derived from the fluorine-containing gas can suppress clogging of the recesses by deposits.
  • the first film includes, as the metal element, at least one transition metal element selected from the group consisting of tungsten, titanium, molybdenum, hafnium, zirconium, and ruthenium, according to any one of [E1] to [E12]. Etching method described.
  • [E15] The first film according to any one of [E1] to [E14], wherein the first film contains at least one tungsten compound selected from the group consisting of tungsten silicide, tungsten silicon nitride, tungsten silicon boron, and tungsten silicon carbon. Etching method.
  • [E16] The etching method according to any one of [E1] to [E15], wherein the protective film contains at least one of silicon, carbon, oxygen, boron, phosphorus, metal, sulfur, bromine, and iodine.
  • the first plasma is generated by supplying a first high frequency power
  • the recess is etched by supplying a continuous wave of second high-frequency power and a pulse of bias power, and the bias power is supplied to a substrate support part for supporting the substrate.
  • the etching method according to any one of [E17] to [E22].
  • a gas supply section containing a gas
  • a plasma generation unit configured to generate a first plasma and a second plasma from the first processing gas and the second processing gas, respectively, in the chamber
  • a control unit Equipped with The control unit includes: forming a protective film on the sidewall of the recess by the first plasma;
  • the plasma processing apparatus is configured to control the gas supply section and the plasma generation section so that the second plasma etches the recess through the opening after forming the protective film.
  • SYMBOLS 1 Plasma processing apparatus, 2... Control part, 10... Plasma processing chamber, 11... Substrate support part, 12... Plasma generation part, 20... Gas supply part, DP... Protective film, F1... First film, F2... Second Film, OP...opening, PL1...first plasma, PL2...second plasma, RS...recess, RSa...side wall, W...substrate.

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Abstract

Un procédé de gravure selon un mode de réalisation donné à titre d'exemple de la présente invention comprend : (a) une étape consistant à fournir un substrat qui est pourvu d'un premier film qui a une partie évidée et d'un second film qui est disposé sur le premier film, le premier film contenant un élément métallique et un élément non métallique, et le second film ayant une ouverture qui correspond à la partie évidée ; (b) une étape de formation d'un film protecteur sur la paroi latérale de la partie évidée au moyen d'un premier plasma qui est généré à partir d'un premier gaz de traitement ; et (c) une étape de gravure de la partie évidée à travers l'ouverture après l'étape (b) au moyen d'un second plasma qui est généré à partir d'un second gaz de traitement qui est différent du premier gaz de traitement. Le second gaz de traitement contient un gaz contenant de l'halogène.
PCT/JP2023/029468 2022-08-25 2023-08-14 Procédé de gravure et appareil de traitement au plasma WO2024043139A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11135481A (ja) * 1997-10-28 1999-05-21 Yamaha Corp エッチング方法
JP2006165164A (ja) * 2004-12-06 2006-06-22 Matsushita Electric Ind Co Ltd ドライエッチング方法及びドライエッチング装置
JP2021077865A (ja) * 2019-11-08 2021-05-20 東京エレクトロン株式会社 エッチング方法及びプラズマ処理装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11135481A (ja) * 1997-10-28 1999-05-21 Yamaha Corp エッチング方法
JP2006165164A (ja) * 2004-12-06 2006-06-22 Matsushita Electric Ind Co Ltd ドライエッチング方法及びドライエッチング装置
JP2021077865A (ja) * 2019-11-08 2021-05-20 東京エレクトロン株式会社 エッチング方法及びプラズマ処理装置

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