Prosecution Insights
Last updated: April 19, 2026
Application No. 18/450,791

THREE-DIMENSIONAL MEMORY DEVICE CONTAINING MULTI-LEVEL SUPPORT BRIDGE STRUCTURES AND METHODS FOR FORMING THE SAME

Non-Final OA §103
Filed
Aug 16, 2023
Examiner
TORNOW, MARK W
Art Unit
2891
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Sandisk Technologies LLC
OA Round
1 (Non-Final)
77%
Grant Probability
Favorable
1-2
OA Rounds
2y 10m
To Grant
90%
With Interview

Examiner Intelligence

Grants 77% — above average
77%
Career Allow Rate
571 granted / 741 resolved
+9.1% vs TC avg
Moderate +13% lift
Without
With
+13.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
10 currently pending
Career history
751
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
44.3%
+4.3% vs TC avg
§102
27.8%
-12.2% vs TC avg
§112
20.4%
-19.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 741 resolved cases

Office Action

§103
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 . Information Disclosure Statement Information disclosure statements (IDS) were submitted on 8/16/23, 3/2/24, 5/10/24, and 6/9/25. Accordingly, the information disclosure statements are being considered by the examiner and initialed copies of the forms are attached to this correspondence. Election/Restrictions Claims 15-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 12/22/25. 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 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. 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 1-6 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Yang et al. (US Patent Application Publication No. 2022/0165747) (“Yang”) in view of Lee (US Patent Application Publication No. 2019/0115356) (“Lee”). Regarding Claim 1, Yang teaches a semiconductor structure, comprising: alternating stacks of insulating layers and electrically conductive layers located over a substrate (see Figure 3B, item 130), wherein each of the alternating stacks laterally extends along a first horizontal direction (see Figure 3B), wherein the alternating stacks are laterally spaced apart from each other along a second horizontal direction by backside trenches that laterally extend along the first horizontal direction (see Figure 3A, note trenches S1 and S2), and wherein the backside trenches comprise first backside trenches (S1) and second backside trenches (S2) that are interlaced along the second horizontal direction perpendicular to the first horizontal direction (see Figure 3A); first backside trench fill structures (Figure 11D, item 514) located in the first backside trenches, wherein each of the first backside trench fill structures comprises a respective first backside support bridge structure (Figure 11D, item 514) located at a first vertical spacing from the substrate (see height depicted in Figure 3A from substrate); and second backside trench fill structures (Figure 11D, item 504) located in the second backside trenches, wherein each of the second backside trench fill structures comprises a second backside support bridge structure (Figure 11D, item 504) located at a second vertical spacing from the substrate that is different from the first vertical spacing (see height depicted in Figure 3A from substrate), and wherein the second backside trenches do not include the first backside support trench fill structures located at the first vertical spacing from the substrate (see Figures 3A and 3B). Yang does not specifically teach that the backside trench fill structures comprise respective sets of support bridge structures. However, Lee teaches forming fill structures in sets of segmented bridge structures (Figure 1, items SA) in a 3D memory structure. It would have been obvious to a person having ordinary skill in the art at the time of effective filing to use the segmented bridge structures of Lee in the device of Yang in order to obtain the known benefits of reduced structural distortion such as bended of stacked gate structures (¶0220). Regarding Claim 2, Yang as modified by Lee further teaches the first backside trenches do not include the second backside support trench fill structures located at the second vertical spacing from the substrate (see Figure 3A of Yang). Regarding Claim 3, Yang further teaches the first and the second backside support trench fill structures comprise a doped semiconductor material (¶0038). Regarding Claim 4, Yang further teaches a vertical plane extending in the second horizontal direction passes through a plurality of the first and the second backside support trench fill structures (see Figures 3A and 3B) Regarding Claim 5, Yang further teaches each of the first backside trench fill structures and the second backside trench fill structures further comprises a respective backside insulating spacer (Figure 11B, items 502+512) contacting sidewalls of a respective pair of alternating stacks of the alternating stacks; and each of the first backside trench fill structures and the second backside trench fill structures further comprises a respective backside contact (Figure 11B, items 504+514) via structure that is laterally surrounded by the respective backside insulating spacer Regarding Claim 6, Yang further teaches a semiconductor material layer located above or within the substrate (Figure 11D, item 110); and source regions embedded within the semiconductor material layer and contacting a bottom surface of a respective one of the backside contact via structures (Figure 11D and ¶0023). Regarding Claim 14, Yang further teaches first backside bridge support structures comprise depth variable support structures having respective bottom surfaces located at different vertical levels from the substrate (see Figure 3B, note bottom surface level differences in S1 and S2). Allowable Subject Matter Claims 7-13 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. None of the prior art, alone or in combination, teaches the language “each backside contact via structure within a respective first backside trench fill structure contacts top surfaces of each first backside support bridge structure within the respective first backside trench fill structure; and each backside contact via structure within a respective second backside trench fill structure is not in direct contact with any second backside support bridge structure within the respective second backside trench fill structure” of Claim 7, “each backside insulating spacer located within a respective first backside trench fill structure contacts bottom surfaces of each first backside support bridge structure within the respective first backside trench fill structure; and each backside insulating spacer located within a respective second backside trench fill structure contacts bottom surfaces of each second backside support bridge structure within the respective second backside trench fill structure” of Claim 8, and “each of the alternating stacks of insulating layers and electrically conductive layers comprises a respective insulating cap layer having a respective top surface within a first horizontal plane in which top surfaces of the second backside support bridge structures are located; and wherein each of the alternating stacks of insulating layers and electrically conductive layers comprise a respective additional insulating cap layer having a respective top surface within a second horizontal plane in which top surfaces of the first backside support bridge structures are located” of Claim 11. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Lu et al. (US Patent Application Publication No. 2017/0047334) Any inquiry concerning this communication or earlier communications from the examiner should be directed to MARK W TORNOW whose telephone number is (571)270-7534. The examiner can normally be reached M-Th 6:30-4:30 EST. 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, Matthew Landau can be reached at 571-272-1731. 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. MARK W. TORNOW Primary Examiner Art Unit 2891 /MARK W TORNOW/Primary Examiner, Art Unit 2891
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Prosecution Timeline

Aug 16, 2023
Application Filed
Jan 09, 2026
Non-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

1-2
Expected OA Rounds
77%
Grant Probability
90%
With Interview (+13.3%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 741 resolved cases by this examiner. Grant probability derived from career allow rate.

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