DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 09/04/2026 has been entered.
Status of the Claims
This is a non-final office action in response to the applicant’s arguments and remarks filed on 07/27/2026. Claims 1-6, 8-21, and 27-28 are pending in the current office action. Claims 1 has been amended by the applicant. Claims 27-28 are new claims. Claims 7 and 22-26 are cancelled.
Status of the Rejection
All 35 U.S.C. § 103 rejections from the previous office action are withdrawn in view of the Applicant’s amendment.
New grounds of rejection under 35 U.S.C. § 102 and under 35 U.S.C. § 103 are necessitated by the amendments.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-6, 9-12, and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Tokashiki et al. (US-20190206723-A1) in view of Suda et al. (US-20210159089-A1) and Dole et al. (WO-2021118862-A2).
Regarding Claim 1, Tokashiki teaches an etching method (Paragraph [0008] method taught includes etching), comprising:
providing a substrate including an etching target layer including a silicon-containing layer, and a mask located on the etching target layer, the mask comprising a metal and having an opening defined by a side wall of the mask (Paragraphs [0018-0019] Figures 2 and 3 substrate provided includes a dielectric material (element 110), where the dielectric material can be silicon nitride, and a mask layer that has openings (element 105), where the openings are shown to have sidewalls of the mask layer. Paragraph [0022] the mask layer can be a metal material or metal oxide);
supplying a process gas including a metal-containing gas (Paragraphs [0023-0024] an etch composition that includes a protective material precursor is supplied for the process. Paragraph [0035] the protective material precursor can be metal containing); and
etching, with plasma generated from the process gas, the etching target layer through the opening while forming a protective layer comprising a metal on a top of the mask and on the side wall of the mask (Paragraph [0027] the dielectric material can be etched and the protective material can be formed in a single etch process, as shown in Figure 2 the protective material (element 115) is formed on the top and side wall of the mask layer (element 120). Paragraph [0023] the etch process can be a plasma etch process)
Tokashiki as outlined above fails to teach wherein the metal-containing gas includes at least one selected from the group consisting of a tungstenhexabromide gas, a tungsten hexachloride gas, a WF5Cl gas, a tungsten hexacarbonyl gas, a molybdenumpentafluoride gas, a vanadiumhexafluoride gas, a platinumhexafluoride gas, a hafniumtetrafluoride gas, and a niobium pentafluoride gas.
Dole teaches methods related to plasma etching (Paragraphs [0001-0007]). Dole teaches that during an etching process where silicon oxide and silicon nitride layers are etched passivation layers are deposited on the sidewalls and mask (Paragraphs [0150-0162] Figures 7A-7C). Dole teaches that a metal fluoride or tungsten containing gas are included within the etch gas as the passivant to form the passivation layers (Paragraph [00164]), where WCl5F can be used as the passivant (Paragraph [0168]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Tokashiki by using as the metal-containing gas within the etch gas, WCl5F as taught by Dole.
This modification would be obvious to one of ordinary skill in the art to substitute the metal-containing gas included in the etch gas taught by Tokashiki with WCl5F taught by Dole since WCl5F is known to be a metal-containing gas capable of being included within an etch gas for the purpose of forming a passivation layer on sidewalls and a mask layer during an etching process and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Modified Tokashiki fails to teach wherein either the mask comprises a metal different from a metal in the metal- containing gas or the etching includes providing no electrical bias for drawing ions.
However, Tokashiki teaches that the hardmask can contain metal (Paragraph [0035]) but fails to provide examples of hardmask. Tokashiki does not teach specific process conditions regarding the use of bias but teaches that the plasma conditions, such as the bias, can be selected by conventional techniques (Paragraph [0043]).
Suda teaches methods of plasma etching a silicon-containing film using a mask (Paragraph [0005]). Suda teaches that a method of etching a silicon-containing film can utilize a metal-containing mask (Paragraph [0017] etching method utilizes a mask. Paragraph [[0021] mask can be metal-containing). Suda teaches that a metal-containing mask can include titanium nitride, titanium oxide, tungsten carbide, or tungsten (Paragraph [0051]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Tokashiki by selecting as the metal containing material for a hardmask, titanium nitride or titanium oxide as taught by Suda. With this modification the instant limitation would be met as the mask would comprise titanium and the metal in the metal-containing gas would comprise tungsten.
This modification would have been obvious to one of ordinary skill in the since titanium nitride and titanium oxide are known as metal containing mask materials and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Regarding Claim 2, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Suda further teaches wherein the mask comprises at least one metallic element selected from the group consisting of tungsten, titanium, tantalum, molybdenum, and rhenium (Suda Paragraph [0051] the metal-containing mask can be tungsten carbide or tungsten).
Regarding Claim 3, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Suda further teaches wherein the mask comprises at least one nonmetallic element selected from the group consisting of boron, carbon, nitrogen, oxygen, silicon, phosphorus, and sulfur (Suda Paragraph [0051] the metal-containing mask can be tungsten carbide).
Regarding Claim 4, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Suda further teaches wherein the mask comprises at least one member selected from the group consisting of tungsten, tungsten carbide, tungsten silicide, titanium, titanium nitride, tantalum nitride, molybdenum carbide, molybdenum nitride, molybdenum silicide, molybdenum boride, molybdenum oxide, rhenium, rhenium oxide, and rhenium nitride (Suda Paragraph [0051] the metal-containing mask can be tungsten carbide or tungsten).
Regarding Claim 5, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Modified Tokashiki further teaches wherein the metal-containing gas is a metal halogen-containing gas (Dole Paragraph [0168] the metal-containing gas can be WCl5F, which contains a halogen).
Regarding Claim 6, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Tokashiki further teaches wherein the metal-containing gas comprises at least one metallic element selected from the group consisting of tungsten, titanium, molybdenum, vanadium, platinum, hafnium, niobium, tantalum, and rhenium (Dole Paragraph [0168] the metal-containing gas can be WCl5F, which contains a tungsten).
Regarding Claim 9, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Modified Tokashiki further teaches wherein the mask comprises a metal different from a metal in the metal-containing gas. (Dole Paragraph [0168] the metal-containing gas can be WCl5F, which contains a tungsten. Suda Paragraph [0051] the metal-containing mask can be titanium nitride or titanium oxide).
Regarding Claim 10, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Tokashiki further teaches wherein the process gas includes a CxHyFz gas, where x and z are each an integer greater than or equal to 1, and y is an integer greater than or equal to 0 (Paragraph [0023] the etch gas can include CF4, C4F8, C5F8, CH2F2, CHF3, or CH3F).
Regarding Claim 11, modified Tokashiki teaches all the limitations of claims 1 and 9 as outlined above. Tokashiki further teaches wherein the CxHyFz gas includes at least one gas selected from the group consisting of CF4, C3F8, C4F8, C4F6, C5F8, CH2F2, CHF3, and CH3F (Paragraph [0023] the etch gas can include CF4, C4F8, C5F8, CH2F2, CHF3, or CH3F).
Regarding Claim 12, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Tokashiki further teaches wherein the process gas further includes an oxygen-containing gas (Paragraph [0023] the etch composition can include an additive gas, that can be O2, CO, CO2, or COS, which are oxygen-containing).
Regarding Claim 19, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Tokashiki further teaches wherein the substrate is a substrate for a logic device (Paragraph [0044] the semiconductor device may be a 3D NAND Flash memory device, a 3D DRAM device, or a 3D crosspoint memory device).
Regarding Claim 20, Tokashiki teaches a method for manufacturing a semiconductor device, the method comprising: the etching method according to claim 1 (Tokashiki teaches all the limitations of claim 1 as outlined above. Paragraph [0018] semiconductor structure formed by the taught method).
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Tokashiki in view of Suda and Dole and further in view of Katsunuma (US-20180130670-A1).
Regarding Claim 13, modified Tokashiki teaches all the limitations of claim 1 as outlined above.
Tokashiki does not teach specific process conditions regarding the use of bias but teaches that the plasma conditions, such as the bias, can be selected by conventional techniques (Paragraph [0043]) and therefore fails to teach wherein the etching includes providing an electrical bias for drawing ions, and the electrical bias has a voltage of -500 to 0 volts inclusive.
Katsunuma teaches a method of plasma etching a silicon-containing layer (Paragraph [0006]). Katsunuma teaches that a bias may be supplied with a negative voltage to the lower electrode (Paragraph [0060]). Katsunuma teaches a range for the voltage of the bias can be -1000V to 0V (Paragraph [0063]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Tokashiki by using a negative voltage within the range taught by Katsunuma.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield predictable results. Tokashiki teaches that the plasma conditions, such as the bias, can be selected by conventional techniques. Katsunuma teaches a suitable range for a negative bias during a plasma etching method. See MPEP 2143(I)(A).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a bias voltage at a level within the disclosed range of -1000 to 0 volts, including at amounts that overlap with the claimed range of -500 to 0 volts. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Claims 15-16 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Tokashiki in view of Suda and Dole and further in view of Briggs et al. (KR-20170106927-A, machine translation)
Regarding Claim 15, modified Tokashiki teaches all the limitations of claim 1 as outlined above.
Tokashiki does not teach specific process conditions but teaches that the plasma conditions can be selected by conventional techniques (Paragraph [0043]), and therefore fails to teach wherein the generated plasma is capacitively coupled plasma or inductively coupled plasma.
Briggs teaches an etching method (Paragraph [0001]) that includes etching a silicon containing layer using a mask layer (Paragraph [0008] substrate is placed in etching chamber, substrate includes silicon oxide containing layer under a patterned mask) and a metal-containing gas (Paragraph [0008] etching gas containing WF6 is supplied to chamber) such that during the etching a protective layer on the top of the mask and the sidewalls (Paragraph [0008] plasma is formed from etching gas and etching silicon oxide containing layer. Paragraph [0023] Figure 6 a passivation layer (element 616) is formed during the etching, and is formed on the top of the mask and the sidewalls of the mask). Briggs further teaches wherein the generated plasma is capacitively coupled plasma or inductively coupled plasma (Paragraph [0012] capacitive couple plasma or inductive couple plasma may be used).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Tokashiki by selecting capacitively coupled plasma or inductively coupled plasma as the means for generating plasma, as Briggs teaches these as suitable ways to generate plasma for an etching process.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield predictable results. Tokashiki teaches that the plasma conditions, such as the means for generating plasma, can be selected by conventional techniques. Briggs teaches capacitively coupled plasma or inductively coupled plasma as suitable ways to generate plasma for an etching process. See MPEP 2143(I)(A).
Regarding Claim 16, modified Tokashiki teaches all the limitations of claim 1 as outlined above.
Tokashiki does not teach specific process conditions but teaches that the plasma conditions can be selected by conventional techniques (Paragraph [0043]), and therefore fails to teach wherein the generated plasma is capacitively coupled plasma, the substrate is supported by a substrate support, and the substrate support receives radio-frequency power for plasma generation.
Briggs teaches an etching method (Paragraph [0001]) that includes etching a silicon containing layer using a mask layer (Paragraph [0008] substrate is placed in etching chamber, substrate includes silicon oxide containing layer under a patterned mask) and a metal-containing gas (Paragraph [0008] etching gas containing WF6 is supplied to chamber) such that during the etching a protective layer on the top of the mask and the sidewalls (Paragraph [0008] plasma is formed from etching gas and etching silicon oxide containing layer. Paragraph [0023] Figure 6 a passivation layer (element 616) is formed during the etching, and is formed on the top of the mask and the sidewalls of the mask). Briggs teaches wherein the generated plasma is capacitively coupled plasma (Paragraph [0012] capacitive couple plasma may be used). Briggs teaches that the substrate can be supported by a substrate support that receives RF power for generating the plasma during the process (Paragraph [0012] Figure 3 substrate (element 204) is supported by a structure that can be considered to include both electrostatic chuck (element 308) and lower electrode (element 334). Lower electrode can be supplied RF power for generating the plasma).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Tokashiki by selecting capacitively coupled plasma as the means for generating plasma and using a substrate support that received RF power to generate the plasma, as Briggs teaches these as suitable ways to generate plasma for an etching process.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield predictable results. Tokashiki teaches that the plasma conditions, such as the means for generating plasma, can be selected by conventional techniques. Briggs teaches these features as suitable ways to generate plasma for an etching process. See MPEP 2143(I)(A).
Regarding Claim 21, modified Tokashiki teaches all the limitations of claim 1 as outlined above.
Tokahiki fails to teach a non-transitory computer readable storage having computer readable instructions stored therein that upon execution by controller circuitry causes a plasma processing apparatus to implement the etching method according to claim 1.
Briggs teaches an etching method (Paragraph [0001]) that includes etching a silicon containing layer using a mask layer (Paragraph [0008] substrate is placed in etching chamber, substrate includes silicon oxide containing layer under a patterned mask) and a metal-containing gas (Paragraph [0008] etching gas containing WF6 is supplied to chamber) such that during the etching a protective layer on the top of the mask and the sidewalls (Paragraph [0008] plasma is formed from etching gas and etching silicon oxide containing layer. Paragraph [0023] Figure 6 a passivation layer (element 616) is formed during the etching, and is formed on the top of the mask and the sidewalls of the mask). Briggs teaches wherein the generated plasma is capacitively coupled plasma (Paragraph [0012] capacitive couple plasma may be used). Briggs teaches that a computer readable storage can store and implement the etching method (Paragraphs [0013-0015] a computer system including a computer readable storage can store and implement the method).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Tokashiki by suppling a non-transitory computer readable storage that would be able to store and implement a method, as taught by Briggs, for the method of modified Tokashiki.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield predictable results. Modified Tokashiki teaches a method that meets all the limitations of claim 1 and Briggs teaches the use of a non-transitory computer readable storage for holding and executing similar methods. One of ordinary skill in the art would have been motivated to use the teachings of Briggs so that the method of modified Tokashiki could be easily saved and run during different operations of the method. See MPEP 2143(I)(A).
Claims 1 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Tokashiki in view of Shamma et al. (KR-20140077865-A, machine translation), Dole, Demmin et al. (US-6635185).
Regarding Claim 1, Tokashiki teaches an etching method (Paragraph [0008] method taught includes etching), comprising:
providing a substrate including an etching target layer including a silicon-containing layer, and a mask located on the etching target layer, the mask comprising a metal and having an opening defined by a side wall of the mask (Paragraphs [0018-0019] Figures 2 and 3 substrate provided includes a dielectric material (element 110), where the dielectric material can be silicon nitride, and a mask layer that has openings (element 105), where the openings are shown to have sidewalls of the mask layer. Paragraph [0022] the mask layer can be a metal material or metal oxide);
supplying a process gas including a metal-containing gas (Paragraphs [0023-0024] an etch composition that includes a protective material precursor is supplied for the process. Paragraph [0035] the protective material precursor can be metal containing, for example TiCl4); and
etching, with plasma generated from the process gas, the etching target layer through the opening while forming a protective layer comprising a metal on a top of the mask and on the side wall of the mask (Paragraph [0027] the dielectric material can be etched and the protective material can be formed in a single etch process, as shown in Figure 2 the protective material (element 115) is formed on the top and side wall of the mask layer (element 120). Paragraph [0023] the etch process can be a plasma etch process),
Tokashiki as outlined above fails to teach wherein the metal-containing gas includes at least one selected from the group consisting of a tungstenhexabromide gas, a tungsten hexachloride gas, a WF5Cl gas, a tungsten hexacarbonyl gas, a molybdenumpentafluoride gas, a vanadiumhexafluoride gas, a platinumhexafluoride gas, a hafniumtetrafluoride gas, and a niobium pentafluoride gas.
Dole teaches methods related to plasma etching (Paragraphs [0001-0007]). Dole teaches that during an etching process where silicon oxide and silicon nitride layers are etched passivation layers are deposited on the sidewalls and mask (Paragraphs [0150-0162] Figures 7A-7C). Dole teaches that a metal fluoride or tungsten containing gas are included within the etch gas as the passivant to form the passivation layers (Paragraph [00164]), where WCl5F can be used as the passivant (Paragraph [0168]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Tokashiki by using as the metal-containing gas within the etch gas, WCl5F as taught by Dole.
This modification would be obvious to one of ordinary skill in the art to substitute the metal-containing gas included in the etch gas taught by Tokashiki with WCl5F taught by Dole since WCl5F is known to be a metal-containing gas capable of being included within an etch gas for the purpose of forming a passivation layer on sidewalls and a mask layer during an etching process and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Tokashiki fails to teach wherein either the mask comprises a metal different from a metal in the metal- containing gas or the etching includes providing no electrical bias for drawing ions.
However, Tokashiki teaches that the hardmask can contain metal (Paragraph [0035]) but fails to provide examples of hardmask. Tokashiki does not teach specific process conditions regarding the use of bias but teaches that the plasma conditions, such as the bias, can be selected by conventional techniques (Paragraph [0043]).
Shamma methods that include the plasma etching of silicon nitride (Paragraph [0051] a target layer is etched with a plasma etching process that utilizes a mask layer. Paragraph [0022] the target layer can be silicon nitride). Teaches that the use of a bias during a plasma etching process is optional (Paragraph [0107]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Tokashiki by selecting plasma processing conditions such that there was no bias provided for drawing ions, as Shamma teaches that providing a bias is an optional component of etching silicon containing layers.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield a predictable result. This combination would have provided the predictable result of providing a suitable set of plasma etching processing conditions, which would include providing no bias, for the plasma etching of a silicon containing layer. See MPEP 2143(I)(A).
Furthermore, Demmin teaches that material etched is a result effective variable. Specifically, Demmin teaches methods of plasma etching (Column 1 lines 5-12). Demmin teaches that plasma etching processing conditions, including bias, can be varied to achieve a desired etching result (Column 7 lines 15-25). Since this particular parameter is recognized as result-effective variable, i.e. a variable which achieves a recognized result, the determination of the optimum or workable ranges of said variable can be characterized as routine experimentation. See In re Boesch, 617 F. 2d 272, 205 U.S.P.Q. 215 (C.C.P.A. 1980). Thus, it would be obvious to one skilled in the art at the time of the claimed invention to modify the plasma etching processing conditions such that no bias was provided, to yield the expected result of etching the silicon containing layer as desired.
Regarding Claim 14, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Modified Tokashiki further teaches wherein the etching includes providing no electrical bias for drawing ions (Outlined in the rejection of claim 1 above).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Tokashiki in view of Shamma, Dole, and Demmin and further in view of Suda.
Regarding Claim 8, modified Tokashiki teaches all the limitations of claim 1 as outlined above. Modified Tokashiki fails to teach wherein both the mask and the metal-containing gas comprise the same metal.
Suda teaches methods of plasma etching a silicon-containing film using a mask (Paragraph [0005]). Suda teaches that a method of etching a silicon-containing film can utilize a metal-containing mask (Paragraph [0017] etching method utilizes a mask. Paragraph [[0021] mask can be metal-containing). Suda teaches that a metal-containing mask can include titanium nitride, titanium oxide, tungsten carbide, or tungsten (Paragraph [0051]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Tokashiki by selecting as the metal containing material for a hardmask, tungsten carbide or tungsten as taught by Suda. With this modification the instant limitation would be met as the mask would comprise tungsten and the metal in the metal-containing gas would comprise tungsten.
This modification would have been obvious to one of ordinary skill in the since tungsten carbide and tungsten are known as metal containing mask materials and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Briggs in view of Suda, Dole, and Reimer et al. (US-20130126984-A1).
Regarding Claim 1, Briggs teaches an etching method (Paragraph [0001] method of etching dielectric layers), comprising:
providing a substrate including an etching target layer including a silicon-containing layer, and a mask located on the etching target layer, the mask having an opening defined by a side wall of the mask (Paragraph [0008] substrate is placed in etching chamber, substrate includes silicon oxide containing layer under a patterned mask. Paragraph [0011] Figure 2a patterned mask (element 212) includes openings that have a sidewall);
supplying a process gas including a metal-containing gas (Paragraph [0008] etching gas containing WF6 is supplied to chamber); and
etching, with plasma generated from the process gas, the etching target layer through the opening while forming a protective layer comprising a metal on a top of the mask and on the side wall of the mask (Paragraph [0008] plasma is formed from etching gas and etching silicon oxide containing layer. Paragraph [0023] Figure 6 a passivation layer (element 616) is formed during the etching, and is formed on the top of the mask and the sidewalls of the mask).
Briggs as outlined above fails to teach wherein the metal-containing gas includes at least one selected from the group consisting of a tungstenhexabromide gas, a tungsten hexachloride gas, a WF5Cl gas, a tungsten hexacarbonyl gas, a molybdenumpentafluoride gas, a vanadiumhexafluoride gas, a platinumhexafluoride gas, a hafniumtetrafluoride gas, and a niobium pentafluoride gas.
Dole teaches methods related to plasma etching (Paragraphs [0001-0007]). Dole teaches that during an etching process where silicon oxide and silicon nitride layers are etched passivation layers are deposited on the sidewalls and mask (Paragraphs [0150-0162] Figures 7A-7C). Dole teaches that a metal fluoride or tungsten containing gas are included within the etch gas as the passivant to form the passivation layers (Paragraph [00164]), where WCl5F can be used as the passivant (Paragraph [0168]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Briggs by using as the metal-containing gas within the etch gas, WCl5F as taught by Dole.
This modification would be obvious to one of ordinary skill in the art to substitute the metal-containing gas included in the etch gas taught by Briggs with WCl5F taught by Dole since WCl5F is known to be a metal-containing gas capable of being included within an etch gas for the purpose of forming a passivation layer on sidewalls and a mask layer during an etching process and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Modified Briggs fails to teach that the mask comprises a metal and that either the mask comprises a metal different from a metal in the metal- containing gas or the etching includes providing no electrical bias for drawing ions.
Suda teaches methods of plasma etching a silicon-containing film using a mask (Paragraph [0005]). Suda teaches that a method of etching a silicon-containing film can utilize a metal-containing mask (Paragraph [0017] etching method utilizes a mask. Paragraph [[0021] mask can be metal containing. Paragraph [0051] the metal containing mask can be titanium nitride).
Reimer teaches methods related to forming circuits and transistors in semiconductor manufacturing, including the use of hard mask layers (Paragraph [0002]). Reimer teaches that titanium nitride provides the benefit of being able to be patterned with wet etching processes to obtain well-defined features for use as a hard mask layer and can provide superior etch resistivity and patterning efficiency when used as a hard mask layer in plasma etching processes (Paragraph [0029]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Briggs by utilizing a titanium nitride, as taught by Suda, in the etching of a silicon-containing layer. With this modification the instant limitations would be met as the mask layer would comprise a metal (titanium) that would be different than the metal (tungsten) contained in the process gas.
One of ordinary skill in the art would have been motivated to make this modification because, as Reimer teaches, titanium nitride mask layers provide superior etch resistivity and patterning efficiency when used as a hard mask layer in plasma etching processes. Further, this modification would have been the simple substitution of one mask material suitable for use in the plasma etching process of a silicon-containing layer with another such mask material. The simple substitution of one known element for another is likely to be obvious when predictable results are achieved. See MPEP §2143(B). Furthermore, the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP § 2144.07.
Claims 17 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Briggs in view of Suda, Dole, and Reimer, as applied to Claim 1 above, and further in view of Harrison et al. (US-20180323074-A1).
Regarding Claim 17, modified Briggs teaches all the limitations of claim 1 as outlined above.
Modified Briggs fails to teach wherein the protective layer has a greater thickness on the top of the mask than on the side wall of the mask. However, Briggs further teaches that the passivation layer can be thicker near the opening (Paragraph [0023] more passivation is placed near the top of the features and a thinner passivation is placed closer to the bottom of the features).
Harrison teaches methods of plasma etching (Paragraph [0002]). Harrison teaches that a passivation layer may be formed while during the plasma etching process (Paragraph [0073]). Harrison teaches that the passivation layer formed can be deposited on a mask layer and may be deposited in a non-conformal manner (Paragraph [0078]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Briggs by depositing the protective layer in a non-conformal manner as taught by Harrison. When depositing the protective layer in a non-conformal manner, some regions would be thicker than other regions, and it would have been obvious to one of ordinary skill in the art to have selected the top of the mask, as it is one of the regions identified by Briggs where the protective layer is deposited, has having a thicker protective layer than the sidewall of feature, another region identified by Briggs where the protective layer is deposited.
This modification would have been obvious as it can be considered the combination of prior art elements according to known methods to yield predictable results. Modified Briggs teaches a method of etching that includes the deposition of a protective layer and Harrison teaches a manner in which the protective layer may be deposited. This combination would have had the predictable outcome of depositing the protective layer in a non-conformal manner. See MPEP 2143(I)(A). Additionally, the selection of the top of the mask as the region to have a thicker protective layer could be considered obvious as the selection of a finite number of possible solutions to forming a non-conformal protective layer. Briggs identifies the top of the mask, an upper region of the etched feature, and a lower region of the etched feature all as the regions where the protective film is deposited. See MPEP 2143(I)(E).
Regarding Claim 18, modified Briggs teaches all the limitations of claim 1 as outlined above. Briggs further teaches wherein the protective layer has, on the side wall of the mask, a thickness decreasing in a depth direction from an upper portion adjacent to the opening (Paragraph [0023] more passivation is placed near the top of the features and a thinner passivation is placed closer to the bottom of the features. Therefore, the thickness decreases in the depth direction).
Allowable Subject Matter
Claims 27-28 are allowed.
Reasons for Allowance
The following is an examiner’s statement of reasons for allowance: The prior art does not disclose nor render obvious all of the cumulative limitations of independent claims 27 and 28 with particular attention to the limitation “wherein either the mask comprises a metal different from a metal in the metal- containing gas or the etching includes providing no electrical bias for drawing ions… and wherein the protective layer has a greater thickness on the top of the mask than on the side wall of the mask”.
The closest prior art of record is considered to be Tokahiki and Briggs.
Tokashiki teaches an etching method (Paragraph [0008] method taught includes etching), comprising: providing a substrate including an etching target layer including a silicon-containing layer, and a mask located on the etching target layer, the mask comprising a metal and having an opening defined by a side wall of the mask (Paragraphs [0018-0019] Figures 2 and 3 substrate provided includes a dielectric material (element 110), where the dielectric material can be silicon nitride, and a mask layer that has openings (element 105), where the openings are shown to have sidewalls of the mask layer. Paragraph [0022] the mask layer can be a metal material or metal oxide); supplying a process gas including a metal-containing gas (Paragraphs [0023-0024] an etch composition that includes a protective material precursor is supplied for the process. Paragraph [0035] the protective material precursor can be metal containing); and etching, with plasma generated from the process gas, the etching target layer through the opening while forming a protective layer comprising a metal on a top of the mask and on the side wall of the mask (Paragraph [0027] the dielectric material can be etched and the protective material can be formed in a single etch process, as shown in Figure 2 the protective material (element 115) is formed on the top and side wall of the mask layer (element 120). Paragraph [0023] the etch process can be a plasma etch process).
However, Tokashiki teaches that the deposition of the protective layer is conformal and thereby fails to teach fails to teach “wherein the protective layer has a greater thickness on the top of the mask than on the side wall of the mask.”
Briggs teaches an etching method (Paragraph [0001] method of etching dielectric layers), comprising: providing a substrate including an etching target layer including a silicon-containing layer, and a mask located on the etching target layer, the mask having an opening defined by a side wall of the mask (Paragraph [0008] substrate is placed in etching chamber, substrate includes silicon oxide containing layer under a patterned mask. Paragraph [0011] Figure 2a patterned mask (element 212) includes openings that have a sidewall); supplying a process gas including a metal-containing gas (Paragraph [0008] etching gas containing WF6 is supplied to chamber); and etching, with plasma generated from the process gas, the etching target layer through the opening while forming a protective layer comprising a metal on a top of the mask and on the side wall of the mask (Paragraph [0008] plasma is formed from etching gas and etching silicon oxide containing layer. Paragraph [0023] Figure 6 a passivation layer (element 616) is formed during the etching, and is formed on the top of the mask and the sidewalls of the mask).
However, Briggs teaches that the etching process requires an electrical bias and therefore fails to teach that the etching includes providing no electrical bias for drawing ions, or the alternative possibility wherein the mask comprises both a metal that is different from a metal in the metal-containing gas and a metal that is the same as a metal in the metal-containing gas.
The claims are therefore considered to be patentably distinguished from the prior art of record. The prior art of record, whether taken alone or in combination, does not disclose nor render obvious the cumulative limitations of claims 27-28.
Response to Arguments
Applicant’s arguments with respect to claim 1-6 and 8-21 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Applicant’s arguments with respect to the new claims 27 and 28 are found to be persuasive.
Conclusion
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/A.K.L./Examiner, Art Unit 1713 /DUY VU N DEO/Primary Examiner, Art Unit 1713
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