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 .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Election/Restrictions
Applicant’s election with traverse of claims 1-10 and 19-20, and the withdrawal of claims 11-18, in the reply filed on June 15, 2026 are acknowledged.
The Applicant argues that “claim 1 of group I and claim 11 of group II share at least the technical feature "exposing the metal oxide layer within the recessed feature of the substrate to a fluorinating agent in the absence of a plasma to form a modified surface layer"”. However, this technical feature is not a special technical feature as it does not make a contribution over the prior art, see the rejections to claim 1 below for more details. Because the shared technical feature is known in the art, restriction is proper.
The requirement is still deemed proper and is therefore made FINAL.
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 1-6, 9-10 and 19-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Fischer et al. (“Thermal etching of AIF3 and thermal atomic layer etching of Al2O3", Journal of Vacuum Science and Technology A, vol. 38, year 2020, paper#022603).
Regarding claim 1, Fischer discloses a method of performing atomic layer etching (abstract), the method comprising: in a three-dimensional semiconductor device fabrication process (abstract and Fig. 12), heating a substrate comprising a metal oxide layer within a recessed feature of the substrate (1st paragraph in section III.C and Fig. 12); and while heating the substrate, performing an atomic layer etching cycle comprising: exposing the metal oxide layer within the recessed feature of the substrate to a fluorinating agent in the absence of a plasma to form a modified surface layer (HF reads on a fluorinating agent, 1st paragraph in section III.C and Figs. 8 and 12); and exposing the modified surface layer to a volatilizing agent in the absence of the plasma to volatilize the modified surface layer (DMAC reads on a volatilizing agent, 1st paragraph in section III.C and Figs. 8 and 12).
Regarding claim 2, Fischer discloses wherein the fluorinating agent comprises hydrogen fluoride (HF, 1st paragraph in section III.C).
Regarding claim 3, Fischer discloses wherein the volatilizing agent comprises a chlorine donor (DMAC, 1st paragraph in section III.C).
Regarding claim 4, Fischer discloses wherein the volatilizing agent comprises dimethyl aluminum chloride (DMAC, 1st paragraph in section III.C).
Regarding claim 5, Fischer discloses wherein heating the substrate comprises heating the substrate to a temperature of 250 degrees Celsius (1st paragraph in section III.C).
Regarding claim 6, Fischer discloses wherein exposing the metal oxide layer to the fluorinating agent comprises exposing the metal oxide layer to a dose of the fluorinating agent of 0.11 Torr (110 mTorr, 5th paragraph in section III.C).
Regarding claim 9, Fischer discloses wherein the atomic layer etching cycle comprises an etch rate uniformity as a function of depth within the recessed feature of greater than 85% (the last paragraph in section III.C and Fig. 12).
Regarding claim 10, Fischer discloses wherein an etch per cycle (EPC) of the atomic layer etching cycle is greater than 0.10 nanometers/cycle (0.14nm, 1st paragraph in section III.C).
Regarding claim 19, Fischer discloses method of performing atomic layer etching (abstract), the method comprising: in a three-dimensional semiconductor device fabrication process (abstract and Fig. 12), placing a substrate in a processing chamber (Fig. 1), the substrate comprising a metal oxide layer as a surface layer within a recessed feature of the substrate (Al2O3 or HfO2 reads on a metal oxide, 1st and 5th paragraphs in section III.C and Fig. 12); heating the substrate to a temperature of 170 degrees Celsius or higher (1st and 4th paragraphs in section III.C and Fig. 12); and while heating the substrate, performing an atomic layer etching cycle comprising: exposing the metal oxide layer to a fluorinating agent in the absence of a plasma to form a modified surface layer, the metal oxide comprising a group 4 transition metal (HfO2 reads on a group 4 metal oxide, 1st and 5th paragraphs in section III.C); and exposing the modified surface layer to a volatizing agent in the absence of a plasma at a dose selected to provide an etch rate uniformity as a function of depth within the recessed feature of greater than 85% (1st and 5th paragraphs in section III.C and Fig. 12).
Regarding claim 20, Fischer discloses wherein the etch per cycle (EPC) of the atomic layer etching cycle is greater than 0.10 nanometers/cycle (EPC is 0.14nm for Al2O3, 1st paragraph in section III.C; Al2O3 and HfO2 have similar EPC, 5th paragraph in section III.C).
Claim 1 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by Smith et al. (US20180182634).
Regarding claim 1, Smith discloses a method of performing atomic layer etching (abstract), the method comprising: in a three-dimensional semiconductor device fabrication process, heating a substrate comprising a metal oxide layer within a recessed feature of the substrate (paragraph 0119 and Fig. 18); and while heating the substrate, performing an atomic layer etching cycle comprising: exposing the metal oxide layer within the recessed feature of the substrate to a fluorinating agent in the absence of a plasma to form a modified surface layer (HF reads on a fluorinating agent, paragraph 0074); and exposing the modified surface layer to a volatilizing agent in the absence of the plasma to volatilize the modified surface layer (Al(CH3)3 reads on a volatilizing agent, paragraph 0074).
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 of this title, 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.
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.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentbale over Fischer et al. (“Thermal etching of AIF3 and thermal atomic layer etching of Al2O3", Journal of Vacuum Science and Technology A, vol. 38, year 2020, paper#022603) as applied to claim 6 above, in view of Seidek et al. (US20200161140).
Regarding claim 7, Fischer is silent about wherein the recessed feature comprises an aspect ratio of 10:1 (depth:width) or higher. However, Seidek teaches thermal atomic layer etching processes can be used for recessed features (trenches) comprise an aspect ratio of the order of 100 (paragraphs 0006 and 0048). Therefore, it would have been obvious to one of ordinary skill, in the art before the effective filing date of the claimed invention, to use the thermal atomic layer etching process of Fischer to common semiconductor structures as taught by Seidel, with a reasonable expectation of success.
Claim 8 is rejected under 35 U.S.C. 103 as being obvious over Smith et al. (US20180182634) as applied to claim 1 above.
Regarding claim 8, Smith discloses wherein exposing the modified surface layer to the volatilizing agent comprises exposing the modified surface layer to a dose of the volatilizing agent of 100mTorr to 10 Torr (paragraph 0069), which overlaps with the range recited in the instant claim. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). MPEP 2144.05(I).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JIONG-PING LU whose telephone number is (571) 270-1135. The examiner can normally be reached on M-F: 9:00am – 5:00pm. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua L Allen, can be reached at telephone number (571)270-3176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JIONG-PING LU/
Primary Examiner, Art Unit 1713
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