Prosecution Insights
Last updated: April 18, 2026
Application No. 18/308,698

ISOLATION STRUCTURE HAVING AN AIR GAP TO REDUCE PIXEL CROSSTALK

Non-Final OA §103
Filed
Apr 28, 2023
Examiner
NARAGHI, ALI
Art Unit
2817
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Taiwan Semiconductor Manufacturing Company Ltd.
OA Round
1 (Non-Final)
86%
Grant Probability
Favorable
1-2
OA Rounds
2y 8m
To Grant
93%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
666 granted / 771 resolved
+18.4% vs TC avg
Moderate +6% lift
Without
With
+6.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
24 currently pending
Career history
795
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
61.6%
+21.6% vs TC avg
§102
19.0%
-21.0% vs TC avg
§112
13.1%
-26.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 771 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 . Election/Restrictions Applicant's election with traverse of the claims 1-9 in the reply filed on 03/11/2026 is acknowledged. Examiner agrees with applicant’s arguments; therefore, the restriction requirement is withdrawn and all the claims 1-20 are examined. 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. Claim(s) 1-4,8-9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Koo et al (US Pub No. 20140239362). With respect to claim 1, Koo et al discloses a first pixel region (PD,Fig.20A, in the middle); a second pixel region (to the right of the first pixel); and a deep trench isolation (DTI) structure (6T), between the first pixel region and the second pixel region (Fig.20A), filled with an oxide material (DTI, para 41) ,wherein an air gap formed in the oxide material (AG). Koo et al shows majority of the cross sectional area is formed by air gap, but it does not explicitly disclose at least 75% of an area in the DTI structure. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify Koo et al such that airgap is at least 75% of an area in the DTI structure, in order to cut the cost of the device by using less dielectric material for the isolation trench. With respect to claim 2, Koo et al does not explicitly disclose wherein a height of the air gap is in a range of 1.5 microns to 10 microns. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). It would have been obvious to one of ordinary skill in the art at the time of filing of the invention to modify Koo et al such that the height of the air gap is in a range of 1.5 microns to 10 microns, in order to cut cost of the device, by using air as much as possible in the isolation trench. With respect to claim 3, Koo et al does not explicitly disclose wherein a width of the air gap is in a range of 0.7 microns to 1.3 microns. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). It would have been obvious to one of ordinary skill in the art at the time of filing of the invention to modify Koo et al such that wherein a width of the air gap is in a range of 0.7 microns to 1.3 microns, in order to cut cost of the device, by using air as much as possible in the isolation trench. With respect to claim 4, Koo et al discloses, wherein the air gap is formed to reduce optical crosstalk between the first pixel region and the second pixel region (since the airgaps extend all the way near the lens it can reduce optical crosstalk between the pixels). With respect to claim 8, Koo et al discloses wherein the first pixel region and the second pixel region are adjacent pixel regions (Fig.20A). With respect to claim 9, Koo et al discloses wherein the first pixel region (left most pixel,Fig.20A) and the second pixel region (right most pixel) are non-adjacent pixel regions in the pixel array (Fig.20A). Allowable Subject Matter Claims 5-7 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. Claims 10-20 are allowed. The following is the reason for allowance of the claim 10, pertinent arts do not alone or in combination disclose: a first pixel region; a second pixel region; a deep trench isolation (DTI) structure, between the first pixel region and the second pixel region, comprising a first air gap; a first micro-lens formed in the first pixel region; a second micro-lens formed in the second pixel region, wherein a second air gap exists between the first micro-lens and the second micro-lens; a plurality of high absorption regions in the first pixel region; and a respective third air gap formed in each of the plurality of high absorption regions. The following is the reason for allowance of the claim 15, pertinent arts do not alone or in combination disclose: a first pixel region comprising a photodiode, the photodiode comprising a high absorption region filled with an oxide material and a first air gap; a second pixel region; and a deep trench isolation (DTI) structure, between the first pixel region and the second pixel region, filled with the oxide material and a second air gap. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALI N NARAGHI whose telephone number is (571)270-5720. The examiner can normally be reached 10am-6pm. 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, Marlon Fletcher can be reached at 571-272-2063. 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. /ALI NARAGHI/Primary Examiner, Art Unit 2817
Read full office action

Prosecution Timeline

Apr 28, 2023
Application Filed
Apr 04, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

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

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Prosecution Projections

1-2
Expected OA Rounds
86%
Grant Probability
93%
With Interview (+6.3%)
2y 8m
Median Time to Grant
Low
PTA Risk
Based on 771 resolved cases by this examiner. Grant probability derived from career allow rate.

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