Patent Application
20240128092
Exemplary embodiments of the present disclosure relate to a substrate processing method and a substrate processing apparatus.
Japanese Unexamined Patent Publication No. 2018-26566 discloses an atomic layer etching (ALE) method. In this method, a substrate is exposed to a hydrogen fluoride gas to form a fluorinated surface layer on a metal oxide film. Then, the substrate is exposed to a boron-containing gas to remove the fluorinated surface layer from the metal oxide film.
In one exemplary embodiment, a substrate processing method is provided. The method includes: (a) providing a substrate including a metal-containing film and a mask provided on the metal-containing film; (b) forming a protective film on the mask; and (c) etching the metal-containing film after (b), and (c) includes (c1) forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing film by using a first processing gas including a fluorine-containing gas, and (c2) removing the second metal-containing substance by using a second processing gas including a precursor.
Hereinafter, various exemplary embodiments will be described.
In one exemplary embodiment, a substrate processing method includes: (a) providing a substrate including a metal-containing film and a mask provided on the metal-containing film; (b) forming a protective film on the mask; and (c) etching the metal-containing film after (b), and (c) includes (c1) forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing film by using a first processing gas including a fluorine-containing gas, and (c2) removing the second metal-containing substance by using a second processing gas including a precursor.
In the method of the embodiment, etching of the mask is suppressed by the protective film during etching of the metal-containing film. Therefore, the metal-containing film can be selectively etched with respect to other films.
The substrate processing method may further include (d) removing fluorine on a surface of the protective film by using a third processing gas after (c). In this case, a further protective film can be then formed in a short time.
The substrate processing method may further include (e) repeating (b), (c), and (d) after (d). In this case, the etching depth of the metal-containing film can be increased.
In (b), the thickness of the protective film formed on a side surface of the mask may decrease toward the metal-containing film from the upper surface of the mask. In this case, since the thickness of the protective film formed on the metal-containing film is reduced, the etching rate of the metal-containing film is improved.
In (d), plasma generated from the third processing gas is used and the third processing gas may include at least one of an oxygen-containing gas, a hydrogen-containing gas, or a nitrogen-containing gas.
The protective film may contain at least one of silicon, carbon, or metal.
In (c1), the first processing gas may be used without generating plasma.
In (c1), plasma generated from the first processing gas may be used.
The substrate may be heated in at least one of (c1) or (c2). In this case, the reaction between the first metal-containing substance and the fluorine-containing gas or the reaction between the second metal-containing substance and the precursor is accelerated.
The precursor may include a metal-containing precursor. In this case, the metal-containing precursor can react with the second metal-containing substance with low energy.
The metal-containing precursor may include a metal complex. In this case, another highly volatile metal complex is generated by a ligand exchange reaction between the second metal-containing substance and the metal complex.
The metal complex may be a complex including at least one monodentate ligand selected from the group consisting of an alkyl, a hydride, a carbonyl, a halide, an alkoxide, an alkylamide, and a silylamide, or at least one chelate selected from the group consisting of β-diketonate, amidinate, acetamidinate, β-diketiminate, diaminoalkoxide, and metallocene.
The metal contained in the metal-containing precursor may be at least one selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr, and Ti.
The precursor may include a metal-free precursor. In this case, metal residue due to the reaction between the second metal-containing substance and the precursor is hardly generated.
The metal-free precursor may be at least one β-diketone selected from the group consisting of acetylacetone (acac), hexafluoroacetylacetone (hfac), trifluoroacetylacetone (tfac), and tetramethylheptanedione (tmhd).
The metal-containing film may contain at least one metal selected from the group consisting of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd, and Sn.
The metal-containing film may be an oxide or a nitride of the metal.
The fluorine-containing gas may include at least one selected from the group consisting of a hydrogen fluoride gas, a fluorocarbon gas, a nitrogen-containing gas, and a sulfur-containing gas.
In one exemplary embodiment, a substrate processing method includes: (a) providing a substrate including a film to be etched and a mask provided on the film to be etched; (b) forming a metal-containing protective film on the mask; (c) removing a part of the metal-containing protective film after (b); and (d) etching the film to be etched after (c), (b) includes (b1) forming a precursor layer on a side surface of the mask by using a first precursor containing a metal, and (b2) modifying the precursor layer into the metal-containing protective film by using a modifying gas including an oxidizing gas or a reducing gas, and (c) includes (c1) forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing protective film by using a first processing gas including at least one of a halogen-containing gas or an oxygen-containing gas, and (c2) removing the second metal-containing substance by using a second processing gas including a second precursor.
In the method of the embodiment, the metal-containing protective film can be etched at a high selectivity with respect to the film to be etched and the mask.
The first precursor may contain at least one metal selected from the group consisting of Ti, Ta, Ru, Al, Hf, and Sn.
The halogen-containing gas may contain at least one selected from the group consisting of fluorine, chlorine, and bromine.
The second precursor may contain a metal including at least one selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr, and Ti, or a complex of the metal.
The film to be etched may be a silicon-containing film.
In one exemplary embodiment, a substrate processing apparatus includes: a chamber; a substrate support for supporting a substrate in the chamber, the substrate including a metal-containing film and a mask provided on the metal-containing film; a gas supply configured to supply each of a first processing gas including a hydrogen fluoride gas, a second processing gas including a precursor, a third processing gas, and a fourth processing gas for forming a protective film into the chamber; and a controller, the controller is configured to control the gas supply in order to form the protective film on the mask by using the fourth processing gas, the controller is configured to control the gas supply in order to form a second metal-containing substance from a first metal-containing substance contained in the metal-containing film by using the first processing gas after formation of the protective film, the controller is configured to control the gas supply in order to remove the second metal-containing substance by using the second processing gas after formation of the second metal-containing substance, and the controller is configured to control the gas supply in order to remove fluorine on a surface of the protective film by using the third processing gas after removal of the second metal-containing substance.
According to the substrate processing apparatus of the embodiment, etching of the mask is suppressed by the protective film during etching of the metal-containing film. Therefore, the metal-containing film can be selectively etched with respect to other films Furthermore, the fluorine on the surface of the protective film is removed by using the third processing gas. Therefore, a further protective film can be then formed in a short time.
Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same references.
In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a controller 2. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generator 12. The plasma processing chamber 10 has a plasma processing space. In addition, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging the gas from the plasma processing space. The gas supply port is connected to a gas supply 20 to be described later, and the gas discharge port is connected to an exhaust system 40 to be described later. The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting the substrate.
The plasma generator 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). In addition, various types of plasma generators may be used, including an alternating current (AC) plasma generator and a direct current (DC) plasma generator. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in a range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in a range of 200 kHz to 150 MHz.
The controller 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute the various steps described in the present disclosure. The controller 2 may be configured to control each element of the plasma processing apparatus 1 to execute the various steps described herein. In one embodiment, a part or the whole of the controller 2 may be included in the plasma processing apparatus 1. The controller 2 may include, for example, a computer 2a. The computer 2a may include, for example, a central processing unit (CPU) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on the program stored in the storage unit 2a2. The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or combinations thereof The communication interface 2a3 may be communicated with the plasma processing apparatus 1 through a communication line such as a local area network (LAN).
Hereinafter, a configuration example of the plasma processing system will be described.
The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power source 30, and an exhaust system 40. In addition, the plasma processing apparatus 1 includes a substrate support 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 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support 11. In one embodiment, the shower head 13 constitutes at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, side walls 10a of the plasma processing chamber 10, and the substrate support 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 the gas from the plasma processing space. The side wall 10a is grounded. The shower head 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.
The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 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 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 to surround the substrate W on the central region 111a of the main body 111. In one embodiment, the main body 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. In addition, although now shown in the drawing, the substrate support 11 may include a temperature adjusting module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, or the substrate to a target temperature. The temperature adjusting module may include a heater, a heat transfer medium, a flow passage, or combinations thereof A heat transfer fluid such as brine or gas flows through the flow passage. In addition, the substrate support 11 may include a heat transfer gas supply configured to supply a heat transfer gas to a gap between a rear surface of the substrate W and the substrate support surface 111a.
The shower head 13 is configured to introduce at least one processing gas from the gas supply 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. In addition, the shower head 13 includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. The gas introduction unit may include one or more side gas injectors (SGI) attached to one or more openings formed in the side wall 10a, in addition to the shower head 13.
The gas supply 20 may include at least one gas source 21 and at least one flow rate controller 22. In one embodiment, the gas supply 20 is configured to supply at least one processing gas from each corresponding gas source 21 to the shower head 13 through each corresponding flow rate controller 22. Each flow rate controller 22 may include, for example, a mass flow controller or a pressure control type flow rate controller. Furthermore, the gas supply 20 may include one or more flow rate modulation devices that modulate or pulse the flow rate of at least one processing gas.
The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 through at least one impedance matching circuit. The RF power source 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. Accordingly, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power source 31 may function as at least a part of a plasma generator configured to generate plasma from the 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 in the substrate W and ion components in the formed plasma can be drawn to the substrate W.
In one embodiment, the RF power source 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is configured to be coupled to the conductive member of the substrate support 11 and/or the conductive member of the shower head 13 through at least one impedance matching circuit and to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in a range of 13 MHz to 150 MHz. In one embodiment, the first RF generator 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 11 and/or the conductive member of the shower head 13. The second RF generator 31b is configured to be coupled to the conductive member of the substrate support 11 through at least one impedance matching circuit and to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in a range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generator 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 11. Further, in various embodiments, at least one of the source RF signal or the bias RF signal may be pulsed.
In addition, the power source 30 may include a DC power source 32 coupled to the plasma processing chamber 10. The DC power source 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is configured to be connected to the conductive member of the substrate support 11 and 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 embodiment, the first DC signal may be applied to another electrode such as an electrode in the electrostatic chuck. In one embodiment, the second DC generator 32b is connected to the conductive member of the shower head 13 and is 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 or second DC signal may be pulsed. The first and second DC generators 32a and 32b may be provided in addition to the RF power source 31, or the first DC generator 32a may be provided in place of the second RF generator 31b.
The exhaust system 40 may be connected to, for example, a gas discharge port 10e provided in a bottom portion of the plasma processing chamber 10. The exhaust system 40 may include a pressure adjusting valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure adjusting valve. The vacuum pump may include a turbo molecular pump, a dry pump, or combinations thereof.
The metal-containing film MF may contain at least one of oxygen or nitrogen. The metal-containing film MF may contain at least one of a metal oxide or a metal nitride. The metal-containing film MF may contain at least one of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd, or Sn.
The mask MK may contain silicon. The mask MK may contain at least one of a silicon oxide or a silicon nitride. The mask MK may contain carbon (organic matter). The mask MK may contain at least one of photoresist, spin-on carbon, amorphous carbon, or tungsten carbide. The mask MK may include at least one recess RS. Each recess RS may be an opening.
Hereinafter, the method MT1 will be described with reference to
In Step ST1, the substrate W shown in
The protective film PR may be formed on an upper surface MKt and a side surface MKs of the mask MK. The thickness of the protective film PR formed on the upper surface MKt of the mask MK is larger than the thickness of the protective film PR formed on the side surface MKs of the mask MK. The thickness of the protective film PR formed on the side surface MKs of the mask MK may decrease toward the metal-containing film MF from the upper surface MKt of the mask MK. That is, the protective film PR may be a sub-conformal film. The protective film PR may not be formed on the metal-containing film MF in a bottom portion of a recess RS of the mask MK. The thickness of the protective film PR formed on the bottom portion of the recess RS of the mask MK is smaller than the thickness of the protective film PR formed on the upper surface MKt and the side surfaces MKs of the mask MK.
The protective film PR may be a conformal film. In this case, the protective film PR formed on the bottom portion of the recess RS of the mask MK can be selectively removed by, for example, anisotropic etching. Accordingly, while the protective film PR on the upper surface MKt and the side surface MKs of the mask MK remains, the protective film PR on the bottom portion of the recess RS of the mask MK can be removed.
The protective film PR may contain at least one of silicon, carbon, or metal.
In a case where the protective film PR has a silicon oxide film formed by ALD or MLD, a silicon-containing gas such as aminosilane, SiCl4, or SiF4 is used as the precursor gas, and an oxygen-containing gas such as an oxygen gas may be used as the modifying gas.
In a case where the protective film PR has a silicon nitride film formed by ALD or MLD, a silicon-containing gas such as aminosilane, SiCl4, dichlorosilane, or hexachlorodisilane may be used as the precursor gas. As the modifying gas, a nitrogen-containing gas such as an ammonia gas or a nitrogen gas may be used.
In a case where the protective film PR has an organic film formed by ALD, an epoxide, a carboxylic acid, a carboxylic acid halide, a carboxylic acid anhydride, an isocyanate, phenols, or the like may be used as the precursor gas. As the modifying gas, an inorganic compound gas including an N—H bond, an inert gas, a mixed gas of N2 and H2, an H2O gas, or a mixed gas of H2 and O2 may be used.
In a case where the protective film PR has an organic film formed by MLD, an isocyanate, a carboxylic acid, or a carboxylic acid halide may be used as the precursor gas, and an amine or a compound including a hydroxyl group may be used as the modifying gas. Alternatively, a carboxylic acid anhydride may be used as the precursor gas, and an amine may be used as the modifying gas. Alternatively, bisphenol A may be used as the precursor gas, and diphenyl carbonate or epichlorohydrin may be used as the modifying gas.
In a case where the protective film PR has a metal-containing film formed by ALD or MLD, a gas containing a metal such as Ti, Ta, Ru, Al, Hf, or Sn or a metal-containing gas such as a gas containing an oxide, a nitride, a sulfide, or a halide of these metals may be used as the precursor gas. As the modifying gas, an oxidizing gas or a reducing gas such as a hydrogen-containing gas (H2 or the like), an oxygen-containing gas (O2 or the like), a mixed gas of H2 and N2, or a gas containing hydrogen and nitrogen (NH3 or the like) may be used.
After Step ST2, Step ST12 may be performed to remove the protective film PR formed on the bottom portion of the recess RS of the mask MK. Step ST12 may be performed before Step ST3. For example, in a case where the protective film PR is a silicon-containing film, in Step ST12, the protective film PR formed on the bottom portion of the recess RS may be removed by plasma generated from a fluorine-containing gas. For example, in a case where the protective film PR is an organic film, in Step ST12, the protective film PR formed on the bottom portion of the recess RS may be removed by an O2 gas or an H2 gas.
In Step ST3, the metal-containing film MF is etched. The metal-containing film MF may be etched by atomic layer etching (ALE). Step ST3 includes Steps ST31 and ST32. Step ST32 is performed after Step ST31. In Step ST3, Steps ST31 and ST32 may be alternately repeated.
The first processing gas G1 etches the protective film PR, so that the protective film PR on the metal-containing film MF is removed while the protective film PR on the mask MK is thinned. Thus, the surface of the metal-containing film MF is exposed to the first processing gas G1. As a result, the first metal-containing substance MS1 reacts with the first processing gas G1. The first processing gas G1 is supplied from the gas supply 20 into the plasma processing chamber 10. In the plasma processing chamber 10, the substrate W is exposed to the first processing gas G1.
The fluorine-containing gas may include at least one of a hydrogen fluoride gas (HF gas), a fluorocarbon gas, a nitrogen-containing gas, or a sulfur-containing gas. The fluorocarbon gas may include at least one of a C4F6 gas, a C4F8 gas, a C3F8 gas, or a CF4 gas. The nitrogen-containing gas may include an NF3 gas. The sulfur-containing gas may include an SF6 gas.
The examples of the first metal-containing substance MS1 are the same as the examples of the constituent materials of the metal-containing film MF. The second metal-containing substance MS2 may be generated by the reaction between the first metal-containing substance MS1 and the fluorine-containing gas. The second metal-containing substance MS2 may contain the same metal as the metal contained in the first metal-containing substance MS1 and fluorine. The second metal-containing substance MS2 is, for example, a metal fluoride. In one example, the first metal-containing substance MS1 includes an aluminum oxide and the fluorine-containing gas includes a hydrogen fluoride gas. In this case, the second metal-containing substance MS2 includes an aluminum fluoride.
In Step ST31, a surface PRs of the protective film PR may be fluorinated by the reaction between the surface PRs of the protective film PR and the fluorine-containing gas. As a result, fluorine may remain on the surface PRs of the protective film PR.
In Step ST31, the first processing gas G1 may be used without generating plasma, or plasma generated from the first processing gas G1 may be used. In a case where no plasma is generated, the first processing gas G1 may include a hydrogen fluoride gas.
In Step ST31, the substrate W may be heated. The temperature of the substrate support 11 may be 100° C. or higher, 150° C. or higher, or 200° C. or higher. The temperature of the substrate support 11 may be 450° C. or lower. The heating may be performed by plasma generated in the plasma processing chamber 10 or the temperature adjusting module in the substrate support 11. The heating accelerates the reaction between the first metal-containing substance MS1 and the fluorine-containing gas.
After Step ST31, a purge step may be performed. In the purge step, a purge gas is supplied into the plasma processing chamber 10, and then exhausted. The purge gas is, for example, an inert gas such as nitrogen or argon.
The precursor may include a metal-containing precursor. The metal-containing precursor may include a metal complex. The metal complex may be a complex including a monodentate ligand or a chelate. The monodentate ligand may be at least one of an alkyl, a hydride, a carbonyl, a halide, an alkoxide, an alkylamide, or a silylamide. The chelate may be at least one of β-diketonate, amidinate, acetamidinate, β-diketiminate, diaminoalkoxide, or metallocene. The β-diketonate may be at least one of acetylacetonate (acac), hexafluoroacetylacetonate (hfac), trifluoroacetylacetonate (tfac), or tetramethylheptanedionate (tmhd).
The metal contained in the metal-containing precursor may be at least one of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr, or Ti.
The precursor may include a metal-free precursor. The metal-free precursor may include a carbon-containing precursor. The carbon-containing precursor may be at least one of alcohol, β-diketone, amidine, acetamidine, or β-diketimine. The β-diketone may be at least one of acetylacetone (acac), hexafluoroacetylacetone (hfac), trifluoroacetylacetone (tfac), or tetramethylheptanedione (tmhd)
In Step ST32, a volatile third metal-containing substance MS3 may be generated by the reaction between the second metal-containing substance MS2 and the precursor. Accordingly, the second metal-containing substance MS2 is removed. In a case where the precursor includes a metal-containing precursor, the metal-containing precursor can react with the second metal-containing substance with low energy. In a case where the metal-containing precursor includes a metal complex, due to a ligand exchange reaction between the second metal-containing substance MS2 and the metal complex, another highly volatile metal complex is generated. In one example, the second metal-containing substance MS2 includes an aluminum fluoride, and the metal-containing precursor includes tin (II) acetylacetonate (Sn(acac)2). In a case where the precursor includes a metal-free precursor, metal residue due to the reaction between the second metal-containing substance and the precursor is hardly generated. In a case where the metal-free precursor includes a carbon-containing precursor, residue containing a carbon compound is generated. The residue containing a carbon compound may be relatively easily removed.
Similarly to Step ST31, the substrate W may be heated in Step ST32. The heating accelerates the reaction between the second metal-containing substance MS2 and the precursor.
After Step ST32, a purge step may be performed in the same manner as the purge step that is performed after Step ST31.
In a case where the protective film PR contains silicon, an Si—F bond may remain in the surface PRs of the protective film PR after Step ST31. In this case, in a case where plasma PL generated from a third processing gas including an oxygen-containing gas is used, the fluorine atom in the surface PRs of the protective film PR is substituted with an OH group. As a result, an Si—OH bond is formed in the surface PRs of the protective film PR. In a case where plasma PL generated from a third processing gas including a hydrogen-containing gas is used, the fluorine atom in the surface PRs of the protective film PR is substituted with a hydrogen atom. As a result, an Si—H bond is formed in the surface PRs of the protective film PR. In a case where plasma PL generated from a third processing gas including a nitrogen-containing gas is used, the fluorine atom in the surface PRs of the protective film PR is substituted with a nitrogen atom. As a result, an Si—N bond is formed in the surface PRs of the protective film PR.
In a case where the protective film PR contains carbon, a C—F bond may be present in the surface PRs of the protective film PR after Step ST31. In this case, in a case where plasma PL generated from a third processing gas including an oxygen-containing gas or a hydrogen-containing gas is used, the fluorine atom in the surface PRs of the protective film PR is substituted with an H group. As a result, a C—H bond is formed in the surface PRs of the protective film PR. This is because the generated carbon monoxide volatilizes. In a case where plasma PL generated from a third processing gas including a nitrogen-containing gas is used, the fluorine atom in the surface PRs of the protective film PR is substituted with a nitrogen atom. As a result, a C—N bond is formed in the surface PRs of the protective film PR. Alternatively, in a case where plasma PL generated from a third processing gas including a nitrogen-containing gas is used, the surface PRs of the protective film PR is scraped. As a result, in the surface PRs of the protective film PR, the constituent materials of the protective film PR is exposed. In a case where the constituent materials include a C—H bond, in the surface PRs of the protective film PR, the C—H bond is exposed.
In Step ST5, Steps ST2, ST3, and ST4 are repeated. Steps ST2, ST3, and ST4 may be repeated a plurality of times. The etching depth of the metal-containing film MF can be increased through Step ST5.
According to the method MT1 described above, etching of the mask MK is suppressed by the protective film PR during etching of the metal-containing film MF. Therefore, the metal-containing film MF can be selectively etched with respect to other films Furthermore, the fluorine on the surface PRs of the protective film PR is removed through Step ST4. In a case where the fluorine remains on the surface PRs of the protective film PR, the time until the start of the deposition of the protective film PR tends to become longer. In the method MT1 described above, since the fluorine on the surface PRs of the protective film PR is removed in Step ST4, a further protective film PR can be formed in a short time thereafter.
In Step ST2, in a case where the thickness of the protective film PR formed on the side surface MKs of the mask MK decreases toward the metal-containing film MF from the upper surface MKt of the mask MK, the thickness of the protective film PR formed on the metal-containing film MF decreases. Therefore, the protective film PR on the metal-containing film MF can be removed in a short time, and thus the etching rate of the metal-containing film MF is improved.
Although the various exemplary embodiments have been described above, various additions, omissions, substitutions, and changes may be made without being limited to the exemplary embodiments described above. In addition, elements in different embodiments can be combined to form other embodiments. Hereinafter, examples of other embodiments will be described, but the same processes and the like as in the above-described exemplary embodiments will be omitted or simplified.
The substrate processing apparatus may not include the plasma generator 12. In this case, the plasma processing is not performed in the chamber of the substrate processing apparatus. The method MT1 can also be performed using such a substrate processing apparatus.
The first processing gas G1 may include a halogen-containing gas. For example, the first processing gas G1 may include at least one of a chlorine-containing gas or a bromine-containing gas instead of or together with the above-described fluorine-containing gas. The chlorine-containing gas may include at least one of a chlorine (Cl2) gas or a hydrogen chloride (HCl) gas. The bromine-containing gas may include at least one of a bromine (Br2) gas or a hydrogen bromide (HBr) gas. In a case where the plasma is generated from the first processing gas G1 in Step ST31, the halogen-containing gas may contain at least one of silicon or carbon.
In a case where the first processing gas G1 includes a halogen-containing gas, the second metal-containing substance MS2 generated in Step ST31 may be formed by the reaction between the first metal-containing substance MS1 and the halogen-containing gas. The second metal-containing substance MS2 may contain the same metal as the metal contained in the first metal-containing substance MS1 and halogen. The second metal-containing substance MS2 is, for example, a metal halide. Specifically, the second metal-containing substance MS2 may be a metal fluoride, a metal chloride, or a metal bromide. Even in a case where the second metal-containing substance MS2 is a metal halide (a metal chloride or a metal bromide) other than a metal fluoride, the second metal-containing substance MS2 can be removed by the second processing gas G2 including the precursor described above.
The first processing gas G1 may include an oxygen-containing gas instead of or together with the halogen-containing gas. For example, the first processing gas G1 may include at least one of an oxygen (O2) gas, a carbon monoxide (CO) gas, or a carbon dioxide gas (CO2) as the oxygen-containing gas.
In a case where the first processing gas G1 includes an oxygen-containing gas, the second metal-containing substance MS2 generated in Step ST31 may be formed by the reaction between the first metal-containing substance MS1 and the oxygen-containing gas. The second metal-containing substance MS2 may contain the same metal as the metal contained in the first metal-containing substance MS1 and oxygen. The second metal-containing substance MS2 is, for example, a metal oxide. In a case where the second metal-containing substance MS2 is a metal oxide, the second metal-containing substance MS2 can be removed by the second processing gas G2 including the metal-free precursor described above.
According to the method MT2 described above, the residue (for example, a residual material derived from the precursor) present on the substrate W after removal of the second metal-containing substance MS2 can be removed.
The present embodiment is not limited to the metal-containing film MF and can be applied to the etching of a metal-containing film.
In Step ST1a, a substrate Wa shown in
The mask MKa may include at least one recess RS. The mask MKa may contain silicon. The mask MKa may contain at least one of a silicon oxide or a silicon nitride. The mask MKa may contain carbon (organic matter). The mask MKa may contain at least one of photoresist, spin-on carbon, amorphous carbon, or tungsten carbide. The mask MKa may contain a metal. The mask MKa may contain at least one of tin (Sn), tellurium (Te), antimony (Sb), indium (In), silver (Ag), titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), germanium (Ge), or hafnium (Hf). The mask MKa may contain an oxide of Sn or a hydroxide of Sn.
In Step ST2a, a metal-containing protective film PRa shown in
In a case where the metal-containing protective film PRa is formed by ALD or MLD, Step ST2a may include Steps ST21a and ST22a. Step ST22a is performed after Step ST21a. In Step ST2a, Steps ST21a and ST22a may be alternately repeated.
In Step ST21a, a precursor layer is formed on the mask MKa by using a gas of a first precursor containing a metal. The precursor layer may be formed on a side surface of the mask MKa. The precursor layer may be formed or may not be formed on an upper surface of the mask MKa. The precursor layer may be formed or may not be formed on the bottom portion of the recess RS of the mask MKa. As the gas of the first precursor, a gas containing a metal such as Ti, Ta, Ru, Al, Hf, or Sn or a metal-containing gas such as a gas containing an oxide, a nitride, a sulfide, or a halide of these metals may be used.
In Step ST22a, by using a modifying gas including an oxidizing gas or a reducing gas, the precursor layer is modified to form the metal-containing protective film PRa. As the modifying gas, an oxidizing gas or a reducing gas such as a hydrogen-containing gas (H2 or the like), an oxygen-containing gas (O2 or the like), a mixed gas of H2 and N2, or a gas containing hydrogen and nitrogen (NH3 or the like) may be used.
In Step ST3a, a part of the metal-containing protective film PRa is etched. The remaining part of the metal-containing protective film PRa is not etched. A part of the metal-containing protective film PRa may be etched by atomic layer etching (ALE). Step ST3a includes Steps ST31a and ST32a. Step ST32a is performed after Step ST31a. In Step ST3a, Steps ST31a and ST32a may be alternately repeated.
In Step ST31a, as shown in
In Step ST32a, as shown in
In Step ST4a, Steps ST2a and ST3a are repeated. Steps ST2a and ST3a may be repeated a plurality of times. The etching amount of the metal-containing protective film PRa can be controlled by the number of times of repetition of Steps ST2a and ST3a.
In Step ST5a, the film EF to be etched is etched via the recess RS (opening) of the mask MKa on which the metal-containing protective film PRa is formed. The film EF to be etched may be etched by plasma generated from a sixth processing gas. For example, in a case where the film EF to be etched is a silicon-containing film, the sixth processing gas may include a fluorine-containing gas. The fluorine-containing gas may include at least one of a hydrogen fluoride gas (HF gas), a fluorocarbon gas, or a hydrofluorocarbon gas.
According to the method MT3, in Step ST3a, the metal-containing protective film PRa can be etched with a high selectivity with respect to the film EF to be etched and the mask MKa. Further, according to the method MT3, in a case where the mask MKa has a large surface roughness, the surface roughness of the mask MKa can be improved.
From the above description, it will be understood that various embodiments of the present disclosure have been described herein for purposes of description, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the aspects following claims.
Here, the various exemplary embodiments included in the present disclosure are described in (Supplementary Note 1) to (Supplementary Note 24) below.
A substrate processing method including:
The method according to Supplementary Note 1, further including (d) removing fluorine on a surface of the protective film by using a third processing gas after (c).
The method according to Supplementary Note 2, further including (e) repeating (b), (c), and (d) after (d).
The method according to any one of Supplementary Notes 1 to 3, in which in (b), a thickness of the protective film formed on a side surface of the mask decreases toward the metal-containing film from an upper surface of the mask.
The method according to Supplementary Note 2, in which in (d), plasma generated from the third processing gas is used and the third processing gas includes at least one of an oxygen-containing gas, a hydrogen-containing gas, or a nitrogen-containing gas.
The method according to any one of Supplementary Notes 1 to 5, in which the protective film contains at least one of silicon, carbon, or a metal.
The method according to any one of Supplementary Notes 1 to 6, in which in (c1), the first processing gas is used without generating plasma.
The method according to any one of Supplementary Notes 1 to 6, in which in (c1), plasma generated from the first processing gas is used.
The method according to any one of Supplementary Notes 1 to 8, in which in at least one of (c1) or (c2), the substrate is heated.
The method according to any one of Supplementary Notes 1 to 9, in which the precursor includes a metal-containing precursor.
The method according to Supplementary Note 10, in which the metal-containing precursor includes a metal complex.
The method according to Supplementary Note 11, in which the metal complex is a complex including at least one monodentate ligand selected from the group consisting of an alkyl, a hydride, a carbonyl, a halide, an alkoxide, an alkylamide, and a silylamide, or at least one chelate selected from the group consisting of β-diketonate, amidinate, acetamidinate, β-diketiminate, diaminoalkoxide, and metallocene.
The method according to any one of Supplementary Notes 10 to 12, in which a metal contained in the metal-containing precursor is at least one selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr, and Ti.
The method according to any one of Supplementary Notes 1 to 13, in which the precursor includes a metal-free precursor.
The method according to Supplementary Note 14, in which the metal-free precursor is at least one β-diketone selected from the group consisting of acetylacetone (acac), hexafluoroacetylacetone (hfac), trifluoroacetylacetone (tfac), and tetramethylheptanedione (tmhd).
The method according to any one of Supplementary Notes 1 to 15, in which the metal-containing film contains at least one metal selected from the group consisting of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd, and Sn.
The method according to Supplementary Note 16, in which the metal-containing film is an oxide or a nitride of the metal.
The method according to any one of Supplementary Notes 1 to 17, in which the fluorine-containing gas includes at least one selected from the group consisting of a hydrogen fluoride gas, a fluorocarbon gas, a nitrogen-containing gas, and a sulfur-containing gas.
A substrate processing method including:
The method according to Supplementary Note 19, in which the first precursor contains at least one metal selected from the group consisting of Ti, Ta, Ru, Al, Hf, and Sn.
The method according to Supplementary Note 19 or 20, in which the halogen-containing gas contains at least one selected from the group consisting of fluorine, chlorine, and bromine.
The method according to any one of Supplementary Notes 19 to 21, in which the second precursor contains a metal including at least one selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr, and Ti or a complex of the metal.
The method according to any one of Supplementary Notes 19 to 22, in which the film to be etched is a silicon-containing film.
A substrate processing apparatus including:
According to one exemplary embodiment, a substrate processing method and a substrate processing apparatus in which a metal-containing film can be selectively etched with respect to other films are provided.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-111618 | Jul 2021 | JP | national |
This application is a continuation application of PCT Application No. PCT/JP2022/026372, filed on Jun. 30, 2022, which claims the benefit of priority from Japanese Patent Application No. 2021-111618, filed on Jul. 5, 2021. The entire contents of the above listed PCT and priority applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2022/026372 | Jun 2022 | US |
| Child | 18397020 | US |
