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 .
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 term “cryogenic” in claim 1 is a relative term which renders the claim indefinite. The term is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 2, 4, 5, 11, 12, 18 and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated US Publication 2022/0157614 to Oomori et al.
Regarding Claim 1, Oomori et al. teaches an etching method for forming an aperture by selectively etching one or more silicon-containing films (Paragraph 27) in a substrate using a patterned mask layer deposited on top of the one or more silicon-containing films, the method comprising: mounting the substrate (18) in a reaction chamber (11); cooling the substrate to a temperature below approximately 25°C (Paragraph 46); introducing an etching gas C₂H₂F₂ into the reaction chamber (Paragraph 26); converting the etching gas to a plasma; and allowing an etching reaction to proceed between the plasma and the one or more silicon-containing films so that the one or more silicon-containing films are selectively etched versus the patterned mask layer to form the aperture.
Regarding Claim 2, Oomori et al. teaches (Paragraphs 25 and 26) adding one or more hydrofluorocarbon or fluorocarbon etching gases to the etching gas C₂H₂F₂, wherein the one or more hydrofluorocarbon or fluorocarbon etching gases are selected from C4F6, C4F8, C4H₂F₆, CHF₃, CH₂F₂, CH₃F, CF₄, C₂F₆, C3F8, SF₆, NF₃, C₂F₄, C3F₆, C4F₁₀, C₅F₈, C₆F₆, C₁-C₆ CxFyH₂ molecule (x, y, and Z are integers), C₂H₅F, C₃H₇F, C₃H₂F₆, C₂HF₅, C₃H₂F₄, or combination thereof.
Regarding Claim 4, Oomori et al. teaches (Paragraph 41) adding a co-reactant to the etching gas C₂H₂F₂, wherein the co-reactant is selected from O₂, CO, CO2, NO, NO₂, N2O, SO₂, H₂S, COS, O₃, CxOyFz (x, y and Z are integers) selected from COF2, C₂O₂F₂, CxOyFzHm (x, y, Z and m are integers) selected from alcohol, ketone, acidic, ester type molecule selected from CF₃OH, CF₃OCF₃, (CF₃)₂C=O, CF₃COOH, or combinations thereof.
Regarding Claim 5, Oomori et al. teaches (Paragraph 42) adding an inert gas to the etching gas C₂H₂F₂, wherein the inert gas is selected from Ar, Kr, Xe, Ne, N₂, He or combination thereof.
Regarding Claims 11 and 12, Oomori et al. teaches (Paragraph 46) the temperature of the substrate ranges from approximately - 196°C to approximately 300°C and approximately - 196°C to approximately 60°C.
Regarding Claim 18, Oomori et al. teaches a pattern diameter of 100nm (Paragraph 57).
Regarding Claim 20, Oomori et al. teaches (implicit) after the aperture is formed, the temperature of the substrate is increased to greater than -50°C since after etching substrate is necessarily removed from the chamber.
Claim Rejections - 35 USC § 103
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.
Claims 3, 10 and 13-17 are rejected under 35 U.S.C. 103 as being unpatentable over US Publication 2022/0157614 to Oomori et al. in view of US Publication 2023/0215700 to Kumagai et al.
Regarding Claim 3, Oomori et al. teaches the method of the invention substantially as claimed, but does not expressly teach adding an additive to the etching gas C₂H₂F₂, wherein the additive is selected from H₂, SF₆, NF₃, NH₃, Cl₂, BCl₃, BF₃, Br₂, F2, FNO, FNO3, HBr, HCI, HI, IF5, IF₇, HF, B₂H₆, or P-containing gases selected from PF₃, PCl₃, PBr₃, PH₃, POCI₃, PF₅, POF₃, PH₃ or P(R)₃ where R is an alkyl, or fluorinated alkyl groups selected from CF₃. However, Kumagai et al. teaches (Paragraphs 102, 109, 113) additives for CxHyFx dielectric stack etching include HF, H₂, SF₆, NF₃, NH₃, Cl2, Br₂, HBr gas and P-containing gases selected from PF₃, PCl₃, PBr₃, PH₃, POCI₃, PF₅, POF₃, PH₃. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the additive gasses to etch a dielectric stack with predictable results.
Regarding Claims 10 and 13, Oomori et al. teaches the method of the invention substantially as claimed including temperatures below 20°C, but does not expressly teach the temperature of the substrate is below approximately -50°C or approximately - 196°C to approximately -50°C. However, Kumagai et al. teaches (Paragraph 118) teach the temperature of the substrate is below approximately -50°C or approximately - 196°C to approximately -50°C for CxHyFx dielectric stack etching. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the temperature below -50°C in order to increase anisotropy and selectivity with predictable results.
Regarding Claims 14-17, Oomori et al. teaches a high aspect ratio structure (Paragraph 50) but does not expressly teach the aspect ratio of the aperture ranges from 1:1 to 5:1, is above 5:1 or is above 20:1 or ranges from approximately 5:1 to approximately 500:1. However, the aspect ratio is known in the art of fabricating semiconductor devices. For example, Kumagi et al. teaches (Paragraph 122) an aspect ratio of 100 or more for an etched recess using CxHyFx. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the aspect ratio above 5:1 or 20:1 in the method of Oomori et al. in order to form a semiconductor device with predictable results.
Claims 6-9 are rejected under 35 U.S.C. 103 as being unpatentable over US Publication 2022/0157614 to Oomori et al. in view of US Publication 2020/00234962 to Kato et al.
Regarding Claims 6-9, Oomori et al. teaches C₂H₂F₂ but does not expressly teach isomers. However, isomer alternatives are well known for etching gas processing. For example, Kato et al. teaches (Paragraphs 137-141) isomers as alternatives for C₂H₂F₂. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the 4 isomers of C₂H₂F₂ as an etch gas with predictable results.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over US Publication 2022/0157614 to Oomori et al. in view of US Publication 2023/0127597 to Takahashi et al.
Regarding Claim 19, Oomori et al. teaches a high aspect ratio structure (Paragraph 50) and reducing line width (Paragraphs 2 and 4) and a pattern diameter of 100nm (Paragraph 57) but does not expressly teach the aperture has a diameter ranging from approximately 0.1 nm to approximately 500 nm or a diameter less than 100 nm. However, Takahashi et al. teaches (Paragraphs 34 and 35) feature sizes less than 100nm diameter for high aspect ratio etching using CxHyFx (Paragraphs 9 and 29) dielectric stack etching. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the diameter less than 100nm in order to form a semiconductor device with predictable results.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US Publication 2015/0097276 to Kim et al. teaches etching alternating oxide and nitride layers with gas containing C₂H₂F₂.
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/ROBERTS P CULBERT/Primary Examiner, Art Unit 1716