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 without traverse of claims 1-15 and the cancelation of claims 16-23 in the reply filed on December 13, 2025 are acknowledged.
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 1-4 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Wang et al. (US20160141330).
Regarding claim 1, Wang discloses a method for improving etch uniformity across a semiconductor substrate (silicon substrate reads on a semiconductor substrate, paragraphs 0022 and 0053), the method comprising: receiving the semiconductor substrate (paragraph 0052), the semiconductor substrate having a silicon-containing material exposed on a surface of the semiconductor substrate (paragraph 0053); dispensing an etch solution onto the surface of the semiconductor substrate while the semiconductor substrate is spinning at a rotational speed (paragraph 0052), the etch solution comprising a mixture of hydrofluoric acid (HF) and nitric acid (HNO3) (paragraphs 0042-0043); and increasing a concentration of nitrous acid (HNO2) within the etch solution prior to dispensing the etch solution onto the surface of the semiconductor substrate to improve etch uniformity of the silicon-containing material across the semiconductor substrate (paragraphs 0022 and 0044).
Regarding claim 2, Wang discloses wherein the etch solution is dispensed onto the surface of the semiconductor substrate at a location of dispense, and wherein by increasing the concentration of nitrous acid (HNO2) within the etch solution, the etch solution etches the silicon-containing material with a uniform etch rate from the location of dispense to an edge of the semiconductor substrate (paragraphs 0022 and 0052).
Regarding claim 3, Wang discloses wherein the etch solution is dispensed onto the surface of the semiconductor substrate at a center of the semiconductor substrate, and wherein by increasing the concentration of nitrous acid (HNO2) within the etch solution, the etch solution etches the silicon-containing material with a uniform etch rate from the center of the semiconductor substrate to an edge of the semiconductor substrate (paragraphs 0022 and 0052).
Regarding claim 4, Wang discloses wherein the silicon-containing material exposed on the surface of the semiconductor substrate comprises epitaxial silicon (paragraphs 0014 and 0034).
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.
Claims 5-9 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (US20160141330) as applied to claim 1 above in view of Bilodeau et al. (US20180337253).
Regarding claim 5, Wang discloses wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises: etching a doped silicon with the HNA solution to increase the concentration of nitrous acid (nitrite ion in an acidic solution) in the etch solution (claim 1), which is different from the method of increasing nitrous acid (HNO2) concentration as recited in the instant claim. However, Bilodeau teaches that increasing nitrous acid (HNO2) concentration can be achieved by supplying a nitrogen-containing gas to a chemical reservoir containing the etch solution (NO2 gas is bubbled through the removal composition, paragraph 0042). Therefore, it would have been obvious to one of ordinary skill, in the art before the effective filing date of the claimed invention, to substitute the step of increasing nitrous acid (HNO2) concentration in the method of Wang with the step of supplying a nitrogen-containing gas to a chemical reservoir containing the etch solution to increase nitrous acid (HNO2) concentration as taught by Bilodeau, with a reasonable expectation of success. It has been held that substituting equivalents known for the same purpose is obvious. See MPEP 2144.06 II.
Regarding claim 6, Billodeau discloses wherein the nitrogen-containing gas is a nitrogen dioxide (NO2) gas (paragraph 0042).
Regarding claim 7, Billodeau discloses wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises: adding a silicon-containing solution to the etch solution to increase the concentration of nitrous acid (HNO2) in the etch solution (paragraph 0040).
Regarding claim 8, Billodeau discloses wherein the silicon-containing solution comprises silica dissolved in aqueous solution (paragraph 0040).
Regarding claim 9, Billodeau discloses wherein the silicon-containing solution is supplied to a chemical reservoir containing the etch solution (paragraph 0040).
Regarding claim 15, Billodeau discloses wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises: supplying a nitrogen-containing gas to a chemical reservoir containing the etch solution, wherein addition of the nitrogen-containing gas to the etch solution causes the concentration of nitrous acid (HNO2) in the etch solution to be increased to maintain equilibrium in the etch solution (paragraph 0042).
Allowable Subject Matter
Claims 10-14 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
Regarding claim 10, the cited prior art of record, taken either alone or in combination, fails to disclose or render obvious a method wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises: exposing the etch solution to ultra-violet (UV) radiation, wherein the UV radiation photolyzes the nitric acid (HNO3) in the etch solution into nitrous acid (HNO2) to increase the concentration of nitrous acid (HNO2) in the etch solution, in the context of the instant claim.
Regarding claim 11, it is dependent on claim 10.
Regarding claim 12, the cited prior art of record, taken either alone or in combination, fails to disclose or render obvious a method wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises: exposing the etch solution to a noble metal surface, wherein the noble metal surface catalyzes a reaction that converts a portion of the nitric acid (HNO3) in the etch solution into nitrous acid (HNO2) to increase the concentration of nitrous acid (HNO2) in the etch solution, in the context of the instant claim.
Regarding claims 13-14, they are dependent on claim 12.
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