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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claim 1-26, in the reply filed on 12/03/2025 is acknowledged.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 26 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 26 recites the limitation "the plasma includes… a greatest amount of the HF species". It is unclear what is required by this limitation. In order for something to be considered having the “greatest amount” it would have to be clear what is being used in the comparison and would have a “lessor amount”. It is unclear what could be compared such that "the plasma includes… a greatest amount of the HF species". This could be interpreted to mean that the plasma has more HF species than some other object, for example the processing gas, which is not explicitly claimed in claim 26, supplied to form the plasma. This could be interpreted to mean that the plasma has more HF species than other, unclaimed or listed, species within the plasma. This could be interpreted to mean that the plasma has more HF species than some different unclaimed plasma would have.
For the purpose of compact prosecution, this limitation will be considered has having been met if the plasma has HF species.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 1-6, 8, 11-13, and 21-26 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 2, 4, 5, 7, 8, 10, 11, and 15 of U.S. Patent No. 1200835. Although the claims at issue are not identical, they are not patentably distinct from each other for the following reasons:
Regarding Claim 1, the reference patent in claim 1 requires a plasma processing method that provides a substrate with a silicon oxide and silicon nitride film, forms a plasma from an HF gas and a phosphorus-containing gas, and etches the film. This anticipates the limitations: “A substrate processing method, comprising: providing a substrate with a silicon-containing film in a chamber; supplying a process gas containing an HF gas, etching the silicon-containing film in the substrate with the plasma.” Claim 5 of the reference patent requires that the phosphorus-containing gas is a phosphorus halide gas, identical to the instant limitation “supplying a process gas containing … a phosphorus halide gas”. Claims 10 and 11 of the reference patent require “the processing gas further includes a CuHvFw gas (where u and v are integers equal to or greater than 1, and w is an integer equal to or greater than 0)” and that this gas be selected from a group that includes C4H2F6 and C3H2F4, which therefore anticipates the instant limitation “supplying a process gas containing… and at least one gas selected from the group consisting of a C4H2F6 gas, a C4H2F8 gas, a C3H2F4 gas, and a C3H2F6 gas”.
Regarding Claim 2, the reference patent claim 7 requires that the phosphorus-containing gas be selected from a group of gases that includes “PF3 gas, PF5 gas, POF3 gas, HPF6 gas, PCI3 gas, PCl3 gas, POCI3 gas, PBr3 gas, PBr5 gas, POBr3 gas, PI3 gas” which are also in the group of gases required by the instant claim. Therefore, it would have been obvious to have selected one of these from the reference patent.
Regarding Claim 3, the reference patent claim 8 requires that the processing gas further indue an oxygen-containing gas, and therefore anticipates the instant claim.
Regarding Claim 4, the reference patent claim 7 requires that the processing gas contain “at least one” gas from a group of gases that includes gases that contain halogens. It would have been obvious to have selected more than one gas from this list, such that a phosphorus-halide gas and another gas that contained chlorine, bromine, or iodine were selected and therefore the instant limitation would be met.
Regarding Claim 5, the reference patent claim 7 requires that the processing gas contain “at least one” gas from a group of gases that includes some of the same compounds as the instant limitation. It would have been obvious to have selected more than one gas from this list, such that a phosphorus-halide gas and another gas were selected that was also listed in the instant limitation and therefore the instant limitation would be met.
Regarding Claim 6, the reference patent claim 1 requires that the processing gas contain at least one CxFy gas (where x and y are integers equal to or greater than 1), which anticipates the instant limitation.
Regarding Claim 8, the reference patent claims 8 and 9 require that the processing gas further include an oxygen-containing gas and that this gas be selected from the group “02 gas, a CO gas, a CO2 gas, an H20 gas, and an H202 gas”, which is identical to the instant limitation.
Regarding Claim 11, the reference patent claim 1 requires that the substrate have a silicon oxide and a silicon nitride film which anticipates the instant limitation.
Regarding Claim 12, the reference patent claim 2 requires that “substrate has a carbon-containing film defining at least one opening on the film stack” which anticipates the claimed limitation.
Regarding Claim 13, the reference patent claim 1 requires that a bias be supplied and claim 15 requires that “wherein the bias DC signal is a voltage pulse comprising two alternating periods with different voltage levels” which anticipates the instant limitation.
Regarding Claim 21, the reference patent in claim 1 requires a plasma processing method that provides a substrate with a silicon oxide and silicon nitride film, forms a plasma from an HF gas and a phosphorus-containing gas, and etches the film. This anticipates the limitations: “A substrate processing method, comprising: providing a substrate with a silicon-containing film in a chamber; supplying a process gas containing …a fluorine-containing gas, and a phosphorus-containing gas into the chamber to generate plasma, and etching the silicon-containing film in the substrate with the plasma.” Claim 10 of the reference patent requires “the processing gas further includes a CuHvFw gas (where u and v are integers equal to or greater than 1, and w is an integer equal to or greater than 0)”, which therefore anticipates the instant limitation “supplying a process gas containing a CXHyFZ gas where x is an integer greater than or equal to 2, and y and z are integers greater than or equal to 1”.
Regarding Claim 22, the reference patent in claim requires that the plasma be formed from an HF gas, which anticipates the instant limitation.
Regarding Claims 23 and 24, Claims 10 and 11 of the reference patent require “the processing gas further includes a CuHvFw gas (where u and v are integers equal to or greater than 1, and w is an integer equal to or greater than 0)” and that this gas be selected from a group that includes C4H2F6 and C3H2F4, which therefore anticipates the instant limitation.
Regarding Claim 25, the reference patent claim 7 requires that the processing gas contain “at least one” gas from a group of gases that includes some of the same compounds as the instant limitation. It would have been obvious to have selected a gas from this list that was also listed in the instant limitation and therefore the instant limitation would be met.
Regarding Claim 26, the reference patent in claim 1 requires a plasma processing method that provides a substrate with a silicon oxide and silicon nitride film, forms a plasma from an HF gas and a phosphorus-containing gas, and etches the film. This anticipates the limitations: “A substrate processing method, comprising: placing a substrate with a silicon-containing film on a substrate support in a chamber; generating plasma in the chamber; and etching the silicon-containing film using an HF species… wherein the plasma includes an active species of phosphorus”. Claim 10 of the reference patent require “the processing gas further includes a CuHvFw gas (where u and v are integers equal to or greater than 1, and w is an integer equal to or greater than 0)”, which therefore anticipates the instant limitation “etching… using… a CXHyFZ species in the plasma, where x is an integer greater than or equal to 2, and y and z are integers greater than or equal to 1”. As outline the 112 rejection, the specific limitation “wherein the plasma includes … a greatest amount of the HF species” is unclear, and as the reference claims require the use of HF gas in the formation of the plasma, this limitation can be considered met.
Claim Rejections - 35 USC § 103
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-12, 16, and 21-26 are rejected under 35 U.S.C. 103 as being unpatentable over Oomori et al. (US-20180204728-A1) in view of Tomura et al. (US-20210082709-A1).
Regarding Claim 1, Oomori teaches a substrate processing method (Paragraph [0022] teaches a method of etching layers on a substrate), comprising:
providing a substrate with a silicon-containing film in a chamber (Paragraph [0032] substrate is provided with silicon nitride and silicon oxide films and is etched. Paragraphs [0060-0061] substrate is provided on a stage in a chamber for etching to be conducted);
supplying a process gas containing an HF gas and at least one gas selected from the group consisting of a C4H2F6 gas, a C4H2F8 gas, a C3H2F4 gas, and a C3H2F6 gas into the chamber to generate plasma (Paragraphs [0060-0062] a process gas is supplied to the chamber and excited to a plasma. Paragraph [0044] process gas can include HF. Paragraph [0033] process gas comprises C3H2F4); and
etching the silicon-containing film in the substrate with the plasma (Paragraph [0032] silicon containing layers are etched).
Oomori fails to teach that the process gas contains a phosphorus halide gas. However, Oomori teaches that the processing gas can include other gases, such as halogen-containing gases (Paragraph [0044]).
Tomura teaches a plasma etching process that can be used to etch silicon nitride (Paragraphs [0044-0049]). Tomura teaches that the etching process can include Cl2 as part of the etching gas to reduce the amounts of other compounds that adhere to the wafer and ensure the etch occurs appropriately (Paragraph [0127]). Tomura teaches that besides Cl2, other chlorine containing gases, including PCl3, PCl5, and POCl3 are suitable for use in an etching process (Paragraph [0134]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Oomori by including as an additional halogen-containing gas, PCl3, PCl5, or POCl3 as taught by Tomura.
One of ordinary skill would have been motivated to make this modification because Tomura teaches that the inclusion of a chlorine-containing gas reduces the amounts of other compounds that adhere to the wafer and ensures the etch occurs appropriately (Paragraph [0127]). Additionally, this modification could be considered the combination of prior art elements according to known methods to yield predictable results. Oomori teaches that other gases may be included in the processing gas, and Tomura teaches particular gases that are suitable for inclusion in a plasma etching method. See MPEP 2143(I)(A). 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.
Regarding Claim 2, modified Oomori teaches all the limitations of claim 1 as outlined above. As explained in the rejection of claim 1 modified Oomori teaches that the processing gas contains PCl3, PCl5, or POCl3, thereby meeting the instant limitations.
Regarding Claim 3, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches wherein the process gas further contains at least one gas selected from the group consisting of a halogen-containing gas, a carbon-containing gas, an oxygen-containing gas, and a nitrogen- containing gas (Paragraph [0044] halogen and carbon containing gases can be added to the process gas. Paragraph [0042] oxygen containing gases can be added to the process gas. Paragraph [0043] nitrogen gas can be added to the process gas).
Regarding Claim 4, modified Oomori teaches all the limitations of claims 1 and 3 as outlined above. Oomori further teaches wherein the halogen-containing gas is at least one gas selected from the group consisting of a chlorine-containing gas, a bromine-containing gas, and an iodine-containing gas (Paragraph [0044] Cl2, Br2, I2, HCl, HBr, HI, and halogen-containing fluorine compounds can be added to the process gas).
Regarding Claim 5, modified Oomori teaches all the limitations of claims 1 and 3 as outlined above. Oomori further teaches wherein the halogen-containing gas is at least one gas selected from the group consisting of Cl2,SiCl2, SiCl4, CCl4, SiH2Cl2, Si2Cl6, CHCl3, SO2Cl2, BCl3, PCl3, PCl5, POCl3, Br2, HBr, CBr2F2, C2F5Br, PBr3, PBr5, POBr3, BBr3, HI, CF3I, C2F5I, C3F7I,IF5,IF7, I2, and PI3 (Paragraph [0044] Cl2, Br2, I2, HBr, HI, IF5, and IF7 can be added to the process gas).
Regarding Claim 6, modified Oomori teaches all the limitations of claims 1 and 3 as outlined above. Oomori further teaches wherein the carbon-containing gas is at least one gas selected from the group consisting of a CaHb gas, a CcFd gas, and a CHeFf gas, where a and b are integers greater than or equal to 1, c and d are integers greater than or equal to 1, and e and f are integers greater than or equal to 1 (Paragraph [0044] CHF3, CH2F2, CH3F, C2HF4, C2HF5, C3HF7, C3H2F6, C3H3F5, C3H4F4, C3H5F3 and C4HF9 CH4, C2H2, C2H4, C2H6, C3H4, C3H6 and C3H8 can be included in the process gas).
Regarding Claim 7, modified Oomori teaches all the limitations of claims 1 and 3 as outlined above. Oomori further teaches wherein the nitrogen-containing gas is at least one gas selected from the group consisting of an NF3 gas, an N2 gas, and an NH3 gas (Paragraph [0043] process gas can include nitrogen gas. Paragraph [0044] process gas can include NF3 or NH3).
Regarding Claim 8, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches wherein the process gas further contains an oxygen-containing gas, and the oxygen-containing gas is at least one gas selected from the group consisting of an O2 gas, a CO gas, a CO2 gas, an H20 gas, and an H202 gas (Paragraph [0042] process gas can include O2, CO, CO2).
Regarding Claim 9, modified Oomori teaches all the limitations of claim 1 as outlined above.
Oomori fails to teach wherein the process gas further contains at least one gas selected from the group consisting of a boron-containing gas and a sulfur-containing gas. However, Oomori teaches that the processing gas can include other gases, such as halogen-containing gases (Paragraph [0044]).
Tomura teaches a plasma etching process that can be used to etch silicon nitride (Paragraphs [0044-0049]). Tomura teaches that the etching process can include Cl2 as part of the etching gas to reduce the amounts of other compounds that adhere to the wafer and ensure the etch occurs appropriately (Paragraph [0127]). Tomura teaches that besides Cl2, other chlorine containing gases, including sulfuryl chloride (SO2Cl2)are suitable for use in an etching process (Paragraph [0134]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Oomori by including as an additional halogen-containing gas, sulfuryl chloride (SO2Cl2) as taught by Tomura.
One of ordinary skill would have been motivated to make this modification because Tomura teaches that the inclusion of a chlorine-containing gas reduces the amounts of other compounds that adhere to the wafer and ensures the etch occurs appropriately (Paragraph [0127]). Additionally, this modification could be considered the combination of prior art elements according to known methods to yield predictable results. Oomori teaches that other gases may be included in the processing gas, and Tomura teaches particular gases that are suitable for inclusion in a plasma etching method. See MPEP 2143(I)(A). 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.
Regarding Claim 10, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches wherein the process gas further contains an inert gas (Paragraph [0043] process gas can include an inert gas).
Regarding Claim 11, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches wherein the silicon-containing film includes at least one film selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film (Paragraph [0032] substrate is provided with silicon nitride and silicon oxide films).
Regarding Claim 12, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches wherein the substrate includes a mask including an organic film or a metal-containing film, and the organic film or the metal-containing film defines at least one opening in the silicon-containing film (Paragraphs [0032-0033] substrate comprises a mask that has an opening. The mask can be made of amorphous carbon).
Regarding Claim 21, Oomori teaches a substrate processing method (Paragraph [0022] teaches a method of etching layers on a substrate), comprising:
providing a substrate with a silicon-containing film in a chamber (Paragraph [0032] substrate is provided with silicon nitride and silicon oxide films and is etched. Paragraphs [0060-0061] substrate is provided on a stage in a chamber for etching to be conducted);
supplying a process gas containing a CXHyFZ gas, a fluorine-containing gas, and a phosphorus-containing gas into the chamber to generate plasma, where x is an integer greater than or equal to 2, and y and z are integers greater than or equal to 1 (Paragraphs [0060-0062] a process gas is supplied to the chamber and excited to a plasma. Paragraph [0033] process gas comprises C3H2F4 which meets the instant limitations regarding “a CXHyFZ gas”. Paragraph [0044] process gas can include HF, which is a fluorine-containing gas); and
etching the silicon-containing film in the substrate with the plasma Paragraph [0032] silicon containing layers are etched by plasma).
Oomori fails to teach that the process gas contains a phosphorus-containing gas. However, Oomori teaches that the processing gas can include other gases, such as halogen-containing gases (Paragraph [0044]).
Tomura teaches a plasma etching process that can be used to etch silicon nitride (Paragraphs [0044-0049]). Tomura teaches that the etching process can include Cl2 as part of the etching gas to reduce the amounts of other compounds that adhere to the wafer and ensure the etch occurs appropriately (Paragraph [0127]). Tomura teaches that besides Cl2, other chlorine containing gases, including PCl3, PCl5, and POCl3 are suitable for use in an etching process (Paragraph [0134]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Oomori by including as an additional halogen-containing gas, PCl3, PCl5, or POCl3 as taught by Tomura.
One of ordinary skill would have been motivated to make this modification because Tomura teaches that the inclusion of a chlorine-containing gas reduces the amounts of other compounds that adhere to the wafer and ensures the etch occurs appropriately (Paragraph [0127]). Additionally, this modification could be considered the combination of prior art elements according to known methods to yield predictable results. Oomori teaches that other gases may be included in the processing gas, and Tomura teaches particular gases that are suitable for inclusion in a plasma etching method. See MPEP 2143(I)(A). 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.
Regarding Claim 22, modified Oomori teaches all the limitations of claim 21 as outlined above. Oomori further teaches wherein the fluorine-containing gas is a gas to produce an HF species in the chamber (Paragraph [0044] process gas can include HF which would produce HF species).
Regarding Claim 23, modified Oomori teaches all the limitations of claim 21 as outlined above. Oomori further teaches wherein the CXHyFZ gas includes one or more CF3 groups (Paragraph [0033] process gas comprises C3H2F4. Paragraph [0025] C3H2F4 can be 1,3,3,3-tetrafluoropropene, which includes a CF3 group).
Regarding Claim 24, modified Oomori teaches all the limitations of claim 21 as outlined above. Oomori further teaches wherein the CXHyFZ gas contains at least one selected from the group consisting of a C3H2F4 gas, a C3H2F6 gas, a C4H2F6 gas, a C4H2F8 gas, and a C5H2F6 gas (Paragraph [0033] process gas comprises C3H2F4).
Regarding Claim 25, modified Oomori teaches all the limitations of claim 21 as outlined above. As explained in the rejection of claim 21 modified Oomori teaches that the processing gas contains PCl3, PCl5, or POCl3, thereby meeting the instant limitations.
Regarding Claim 26, Oomori teaches a substrate processing method (Paragraph [0022] teaches a method of etching layers on a substrate), comprising:
placing a substrate with a silicon-containing film on a substrate support in a chamber (Paragraph [0032] substrate is provided with silicon nitride and silicon oxide films and is etched. Paragraphs [0060-0061] substrate is provided on a stage in a chamber for etching to be conducted);
generating plasma in the chamber (Paragraphs [0060-0062] a process gas is supplied to the chamber and excited to a plasma); and
etching the silicon-containing film using an HF species (Paragraph [0044] process gas can include HF, which would form HF species) and a CXHyFZ species in the plasma, where x is an integer greater than or equal to 2, and y and z are integers greater than or equal to 1 (Paragraph [0033] process gas comprises C3H2F4, which would form species meeting the instant limitation),
wherein a greatest amount of the HF species (as outlined in the 112 rejection, as the prior art teaches that the plasma comprises HF species, this limitations is met).
Oomori fails to teach that the plasma includes an active species of phosphorus. . However, Oomori teaches that the processing gas can include other gases, such as halogen-containing gases (Paragraph [0044]).
Tomura teaches a plasma etching process that can be used to etch silicon nitride (Paragraphs [0044-0049]). Tomura teaches that the etching process can include Cl2 as part of the etching gas to reduce the amounts of other compounds that adhere to the wafer and ensure the etch occurs appropriately (Paragraph [0127]). Tomura teaches that besides Cl2, other chlorine containing gases, including PCl3, PCl5, and POCl3 are suitable for use in an etching process (Paragraph [0134]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Oomori by including as an additional halogen-containing gas, PCl3, PCl5, or POCl3 as taught by Tomura.
One of ordinary skill would have been motivated to make this modification because Tomura teaches that the inclusion of a chlorine-containing gas reduces the amounts of other compounds that adhere to the wafer and ensures the etch occurs appropriately (Paragraph [0127]). Additionally, this modification could be considered the combination of prior art elements according to known methods to yield predictable results. Oomori teaches that other gases may be included in the processing gas, and Tomura teaches particular gases that are suitable for inclusion in a plasma etching method. See MPEP 2143(I)(A). 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 13-14, and 17-20 are rejected under 35 U.S.C. 103 as being unpatentable over Oomori in view of Tomura, as applied to claim 1 above, and further in view of Qin et al. (WO-2019108844-A1)
Regarding Claim 13, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches that the etching includes supplying a bias (Paragraph [0045]).
Modified Oomori fails to teach wherein the etching includes applying an electrical bias to a substrate support during a first period and a second period that alternates with the first period, and the electrical bias in the first period is zero or at a first level, and the electrical bias in the second period is at a second level higher than the first level.
Qin teaches methods of etching that include the etching of an alternating stack of silicon oxide and silicon nitride layers (Paragraph [0004]). Qin teaches that during the etching process of a silicon oxide layer a bias of less than 150V is provided (Paragraph [0019]). Qin teaches that during the etching process of a silicon nitride layer a bias of 150 to 400V is provided (Paragraph [0020]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Oomori by using supplying a bias as taught by Qin during the etching process. It would have been further obvious to supply a substrate with a silicon nitride layer as the uppermost silicon containing layer to be etched, such that the first period would comprise etching silicon nitride and the second period would comprise etching a silicon oxide layer underneath the silicon nitride layer. With this modification the instant limitations would be met.
This modification would have been obvious to one of ordinary skill in the art as it could be considered the combination of prior art elements according to known methods to yield predictable results. This modification would have had the predictable result of supplying a suitable bias over two periods for the etching of silicon nitride and silicon oxide layers. See MPEP 2143(I)(A).
Regarding Claim 14, modified Oomori teaches all the limitations of claims 1 and 13 as outlined above. Oomori further teaches applying a high-frequency power to a lower electrode that is also the holding stage for the substrate (Paragraph [0060] Figure 3, lower electrode (element 14) holds substrate (element 18)).
Oomori fails to teach wherein the etching includes providing radio frequency power, to generate plasma, to the substrate support or an upper electrode facing the substrate support during a third period and a fourth period that alternates with the third period, the radio frequency power in the third period is zero or at a third level, and the radio- frequency power in the fourth period is at a fourth level higher than the third level, and the second period and the fourth period at least partially overlap.
Qin teaches methods of etching that include the etching of an alternating stack of silicon oxide and silicon nitride layers (Paragraph [0004]). Qin teaches that during the etching process of a silicon oxide layer a radio frequency power of at least 2000W is supplied (Paragraph [0019]). Teaches that during the etching process of a silicon nitride layer radio frequency power of at least 2000W is supplied (Paragraph [0020]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Oomori by using the radio frequency power settings taught by Qin for the etching of the silicon oxide and silicon nitride layers. With this modification the fourth and the second periods would overlap as the same period of etching a silicon oxide layer. It would have been obvious to one of ordinary skill in the art to have selected and incorporated radio frequency powers for the third and fourth periods at a levels within the disclosed range of at least 2000W, including at amounts that overlap with the claimed range where the power of the power supplied during the fourth period is higher than the power supplied during the third period. 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).
This modification would have been obvious to one of ordinary skill in the art as it could be considered the combination of prior art elements according to known methods to yield predictable results. This modification would have had the predictable result of supplying a suitable radio frequency power for generating plasma over two periods for the etching of silicon nitride and silicon oxide layers. See MPEP 2143(I)(A).
Regarding Claim 17, modified Oomori teaches all the limitations of claim 1 as outlined above. Oomori further teaches that the etching includes supplying a bias (Paragraph [0045]).
Modified Oomori fails to teach wherein the etching includes a first process of setting the chamber to a first pressure, applying a first electrical bias to a substrate support, and etching the silicon-containing film, and a second process of setting the chamber to a second pressure, applying a second electrical bias to the substrate support, and etching the silicon-containing film, and the first pressure differs from the second pressure or the first electrical bias differs from the second electrical bias, or the first pressure differs from the second pressure and the first electrical bias differs from the second electrical bias.
Qin teaches methods of etching that include the etching of an alternating stack of silicon oxide and silicon nitride layers (Paragraph [0004]). Qin teaches that during the etching process of a silicon oxide layer a bias of less than 150V is provided and a chamber pressure of 10 to 20 mTorr is provided (Paragraph [0019]). Qin teaches that during the etching process of a silicon nitride layer a bias of 150 to 400V is provided and a chamber pressure of 30 to 100 mTorr is provided (Paragraph [0020]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Oomori by etching, as a first process, a silicon nitride layer using the pressure and bias settings taught by Qin, and then etching, as a second process, a silicon oxide layer underneath the silicon nitride layer, using the pressure and bias settings taught by Qin. With this modification the instant limitations would be met.
This modification would have been obvious to one of ordinary skill in the art as it could be considered the combination of prior art elements according to known methods to yield predictable results. This modification would have had the predictable result of supplying a suitable bias and pressure over two periods for the etching of silicon nitride and silicon oxide layers. See MPEP 2143(I)(A).
Regarding Claim 18, modified Oomori teaches all the limitations of claims 1 and 17 as outlined above. Qin further teaches herein the first pressure is higher than the second pressure (Paragraph [0020] the pressure for etching silicon nitride layer is 30 to 100 mTorr. Paragraph [0019] the pressure for etching a silicon oxide layer is 10 to 20 mTorr. As outlined above, the etching of the silicon nitride film would be considered the first process and the etching of the silicon oxide film would be considered the second process).
Regarding Claim 19, modified Oomori teaches all the limitations of claims 1 and 17 as outlined above. Qin further teaches wherein an absolute value of the first electrical bias is greater than an absolute value of the second electrical bias (Paragraph [0020] the bias supplied during the etching of the silicon nitride layer, equivalent to the first process, is 150 to 400V. Paragraph [0019] the bias supplied during the etching of the silicon oxide layer, equivalent to the second process, is less than 150V).
Regarding Claim 20, modified Oomori teaches all the limitations of claims 1 and 17 as outlined above.
Oomori fails to teach wherein the first process and the second process are repeated alternately. However, Oomori teaches that the etching process can be conducted such that multiple layers of silicon oxide and silicon nitride are etched (Figures 1-3, multiple layers are shown stacked and etched).
Qin further teaches that processes of etching silicon oxide and silicon nitride layers can be repeated (Paragraph [0021]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Oomori but repeating the first and second processes as outlined above, in order to etch through multiple layers of silicon oxide and multiple layers of silicon nitride.
This modification would have been obvious to one of ordinary skill in the art as it could be considered the combination of prior art elements according to known methods to yield predictable results. This modification would have had the predictable result of supplying a suitable bias and pressure over two periods for the etching of silicon nitride and silicon oxide layers, and then repeated those two periods to etch through further layers of silicon nitride and silicon oxide. See MPEP 2143(I)(A).
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Oomori in view of Tomura and Qin, as applied to claims 1 and 13 above, and further in view of Kim et al. (US-20210104382-A1).
Regarding Claim 15, modified Oomori teaches all the limitations of claims 1 and 13 as outlined above.
Modified Oomori fails to teach wherein the electrical bias is a pulsed voltage.
Kim teaches methods of plasma etching (Paragraph [0002]). Kim teaches that during plasma etching a bias power can be pulsed (Paragraph [0037]). Kim teaches that pulsing the bias power can increase an etching rate without clogging of holes (Paragraph [0138]).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Oomori by pulsing the bias power as taught by Kim.
One of ordinary skill in the art would have been motivated to make this modification because Kim teaches that pulsing the bias power can increase an etching rate without clogging of holes (Paragraph [0138]). Additionally, this modification would have been obvious to one of ordinary skill in the art as it could be considered the combination of prior art elements according to known methods to yield predictable results. This modification would have had the predictable result of supplying a suitable bias for a plasma etching process. See MPEP 2143(I)(A).
Conclusion
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/A.K.L./Examiner, Art Unit 1713 /DUY VU N DEO/Primary Examiner, Art Unit 1713