Prosecution Insights
Last updated: April 19, 2026
Application No. 18/278,071

METHOD OF CLEANING SILICON WAFER, METHOD OF MANUFACTURING SILICON WAFER, AND SILICON WAFER

Final Rejection §103
Filed
Aug 21, 2023
Examiner
DEO, DUY VU NGUYEN
Art Unit
1713
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Shin-Etsu Handotai Co. Ltd.
OA Round
2 (Final)
82%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
89%
With Interview

Examiner Intelligence

Grants 82% — above average
82%
Career Allow Rate
842 granted / 1023 resolved
+17.3% vs TC avg
Moderate +7% lift
Without
With
+7.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
19 currently pending
Career history
1042
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
44.7%
+4.7% vs TC avg
§102
29.0%
-11.0% vs TC avg
§112
13.7%
-26.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1023 resolved cases

Office Action

§103
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 . Response to Amendment Claims 14, 16, 18-33 are pending. Claims 18-20 are withdrawn from consideration as non-elected group. Claims 14, 16 are rejected under prior art. Claims 21-33 are allowed. Claim Rejections - 35 USC § 103 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 (i.e., changing from AIA to pre-AIA ) 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. 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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. The factual inquiries 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. Claim(s) 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shigeru et al. (JP2002100599A). With respect to claim 14 Shigeru et al. JP2002100599A describes method comprising alternately repeating a cleaning step 11 and step 12, wherein step 11 includes a cleaning solution containing ammonia or claimed an aqueous solution containing ammonium hydroxide and step 12 includes dissolved ozone aqueous solution, which would form an oxide film on the silicon wafer (page 2 of the translation). The ammonia cleaning solution has a concentration of ammonia from 0.01 to 2 % by weight, which would provide ammonium hydroxide in the solution with concentration of those less than 0.051 % by mass. Overlapping ranges are held obvious. See MPEP 2144.05. 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). Therefore, one skill in the art would find it obvious before the effective filing date of the invention to use ranges including claimed ranges to provide a cleaning composition with expected results. The ammonia cleaning solution would provide roughened wafer surfaces since the process has the same steps with the same chemicals with overlapping ammonia concentration as that of the claimed invention. Unlike claimed invention, Shigeru doesn’t describe the ammonia cleaning solution roughen the front and rear faces or rear face of the silicon wafer. However, he teaches that wafer surfaces are increasingly required to be free from particles, impurities, organic matter and processing damage (page 2, paragraph 2 of the translation). Therefore, it would have been obvious for one skilled in the art before the effective filing date of the invention to clean the surfaces of the silicon wafer including the front the rear in order to provide a silicon wafer free of contaminates with expected results. With respect to the limitation of determining the concentration, cleaning temperature and processing time in advance, before the actual process is carried out, it is obvious and within the knowledge of one skilled in the art as Shigeru also describes “When the temperature exceeds the limit, this solution becomes a strong acid, dissociation of organic acids in the solution is suppressed, the complexing action is reduced, the surface potential of the fine particles becomes close to 0, and the oxide film on the wafer surface is completely removed. As a result, the particles re-adhere to the wafer surface” (page 3 of the translation). Without the knowledge of the processing conditions before the actual process or determining the process conditions in advance, the surface roughness would not be suppressed, the process will not be successful and wafers will be damaged. Claim(s) 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shigeru as applied to claim 14 above, and further in view of admitted prior art (background art of the specification). With respect to claim 16, Shigeru doesn’t describe performing CMP polishing on one side of the cleaned silicon wafer to obtain a silicon wafer with only a side opposite to the one side is selectively roughened. Background art of the specification (paragraphs 3) describes known process of a silicon wafer including steps of double-side polishing step, transporting the wafer to a cleaning process, and then transporting to the CMP for a single-side polishing. Therefore, it would have been obvious for one skilled in the art before the effective filing date of the invention to perform known processing steps of the wafer including single-side CMP step because it would provide silicon wafer for manufacturing semiconductor devices with expected results. The single-side polishing step would leave the opposite side unpolished or roughened that is produced from the cleaning steps. Allowable Subject Matter Claims 21-33 are allowed because the applied prior art Shigeru, even though describes cleaning the silicon wafer with two steps using ammonia cleaning solution; however, Shigeru doesn’t describe the cleaning step using the ammonia solution has an etching selectivity ratio of Si to SiO2 of 95 or more to clean the silicon wafer. Response to Arguments Applicant’s remarks that Shigeru doesn’t teach a method that roughens a surface of silicon wafer is found unpersuasive. As pointed out by the Applicant’s “Shigeru actually disparages surface roughness as an undesirable result to be suppressed and avoided at multiple instances” with his teaching of “in step 23, the particles and metal impurities taken into the oxide film in steps 21 and 22 are separated from the wafer surface by dissolvent the oxide film. In this step, the oxide film is not completely removed but remains on the wafer surface. Therefore, surface roughness due to cleaning can be suppressed”. This clearly shows that a surface roughness is formed during his process since Shigeru’s process has the same steps with the same chemicals with overlapping ammonia concentration as that of the claimed invention and it would provide claimed roughen the surfaces of the silicon wafer because claim 14 doesn’t require any surface roughness value. Therefore, under the broadest reasonable interpretation, MPEP 2111, any kind or amount of surface roughness will read on claimed roughening the surfaces of the silicon wafer. With respect to applicant’s remarks that Shigeru does not focus on any relationship concerning the surface roughening with the process parameters such as the ammonium hydroxide concentration, cleaning temperature and time. This is found unpersuasive because Shigeru is aware of the roughness created by the cleaning process as also pointed out by the applicant with Shigeru’s description of “the concentration of ozone contained in the dissolved ozone water is 1 to 20 ppm. Preferably it is 2 to 15 ppm. If the amount is less than 1 ppm, an oxide film cannot be uniformly formed on the wafer surface, so that an aqueous solution containing ammonia etches the surface, resulting in surface roughness. In step 23, the particles and metal impurities taken into the oxide film in steps 21 and 22 are separated from the wafer surface by dissolving the oxide film. In this step, the oxide film is not completely removed but remains on the wafer surface. Thereby, surface roughness due to cleaning can be suppressed,” and Shigeru also describes “When the temperature exceeds the limit, this solution becomes a strong acid, dissociation of organic acids in the solution is suppressed, the complexing action is reduced, the surface potential of the fine particles becomes close to 0, and the oxide film on the wafer surface is completely removed. As a result, the particles re-adhere to the wafer surface” (page 3 of the translation); furthermore, the fact that he teaches an amount of ozone concentration between 1-20ppm, ammonia concentration of 0.01-2% show that these must be determined beforehand. This shows the process parameters would affect the surface roughness. Therefore, it would have been obvious to any skilled in the art to determine the processing parameters including the concentration, processing times and desired surface roughness in advance. Without the knowledge of the processing conditions before the actual process or determining the process conditions in advance, a desired surface roughness would not be suppressed and the process will not be successful and wafers will be damaged. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DUY VU NGUYEN DEO whose telephone number is (571)272-1462. The examiner can normally be reached 9-5 M-F. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua Allen can be reached at 571-272-3176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /DUY VU N DEO/Primary Examiner, Art Unit 1713 2/2/2026
Read full office action

Prosecution Timeline

Aug 21, 2023
Application Filed
Sep 08, 2025
Non-Final Rejection — §103
Dec 10, 2025
Response Filed
Feb 02, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
82%
Grant Probability
89%
With Interview (+7.1%)
2y 6m
Median Time to Grant
Moderate
PTA Risk
Based on 1023 resolved cases by this examiner. Grant probability derived from career allow rate.

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