Prosecution Insights
Last updated: April 19, 2026
Application No. 17/645,794

METHODS OF FORMING SEMICONDUCTOR DEVICES

Non-Final OA §102
Filed
Dec 23, 2021
Examiner
ISAAC, STANETTA D
Art Unit
2898
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Yangtze Memory Technologies Co. Ltd.
OA Round
3 (Non-Final)
86%
Grant Probability
Favorable
3-4
OA Rounds
2y 7m
To Grant
48%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
811 granted / 948 resolved
+17.5% vs TC avg
Minimal -38% lift
Without
With
+-37.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
57 currently pending
Career history
1005
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
49.5%
+9.5% vs TC avg
§102
44.6%
+4.6% vs TC avg
§112
5.4%
-34.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 948 resolved cases

Office Action

§102
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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 5/14/25 has been entered. Information Disclosure Statement The information disclosure statement (IDS) was submitted on 2/06/26. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. Specification The specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification. Claim Rejections - 35 USC § 102 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 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. Claim(s) 1-20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Nagumo (US 2017/0309638, hereinafter referred to as “Nagumo”). Nagumo discloses the semiconductor device as claimed. See figures 4A-4M and corresponding text, where Nagumo teaches, in claim 1, a method for semiconductor device fabrication, the method comprising: forming a vertical structure in a stack of layers (110) with an end in a first layer (30) by a first processing that is performed on a first side of a first die, the stack of layers and the first layer being on the first side of the first die: and replacing the first layer with a second layer (80) by a second processing that is performed on a second side of the first die that is opposite to the first side, a material of the first layer having a better etch selectivity to the stack of layers than a material of the second layer (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 2, wherein the material of the first layer includes tungsten and the material of the second layer includes polysilicon (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 3, wherein the vertical structure corresponds to a channel structure including a channel layer (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 4, wherein the first layer is included in an initial first stack of layers in a core region of the first die, the stack of layers corresponds to an initial second stack of layers, and the method further comprises: forming the initial second stack of layers that comprises insulating layers and sacrificial gate layers stacked alternatingly over the initial first stack of layers (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 5, wherein forming the vertical structure comprises: forming a channel hole in the stack of layers with an end in the first layer; and forming the channel structure in the channel hole (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 6, wherein the channel structure includes a blocking insulating layer, a charge storage layer and a tunneling insulating layer (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 7, wherein replacing the first layer with the second layer further comprises: removing the first layer by the second processing that is performed on the second side of the first die: and removing the blocking insulating layer, the charge storage layer, and the tunneling insulating layer from an end of the channel structure by the second processing that is performed on the second side of the first die (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 8, wherein replacing the first layer with the second layer further comprises: forming the second layer in contact with the channel layer at an end of the channel structure (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 9, wherein the second layer corresponds to a semiconductor layer (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 10, wherein replacing the first layer with the second layer further comprises: forming a liner portion of the second layer the liner portion contacting the channel layer at an end of the channel structure; performing ion implantation to dope the liner portion; and forming a bulk portion of the second layer (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 11, further comprising: forming a pad structure on the second side of the first die, the pad structure being conductively connected with the second layer (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 12, wherein the vertical structure corresponds to a dummy channel structure (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 13, wherein the first layer is included in an initial first stack of layers in a staircase region of the first die, the stack of layers corresponds to an initial second stack of layers, and the method further comprises: forming the initial second stack of layers that comprises insulating layers and sacrificial gate layers stacked alternatingly over the initial first stack of layers; forming stair steps based on the initial second stack of layers in the staircase region; and planarizing the staircase region using an insulating material (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 14, wherein forming the vertical structure comprises: forming a dummy channel hole in the stack of layers, an end of the dummy channel hole being in the first layer; and forming the dummy channel structure in the dummy channel hole (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 15, wherein the vertical structure corresponds to a gate line slit structure (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 16, wherein the first layer is included in an initial first stack of layers in a gate line slit region of the first die, the stack of layers corresponds to an initial second stack of layers, and the method further comprises: forming the initial second stack of layers that comprises insulating layers and sacrificial gate layers stacked alternatingly over the initial first stack of layers (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 17, wherein forming the vertical structure comprises: forming channel structures in the initial second stack of layers; forming a trench in the initial second stack of layers with an end in the first layer; replacing, via the trench, the sacrificial gate layers with gate layers; and forming a gate line slit structure in the trench (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 18,further comprising: forming a punch through contact structure in a punch through region by the first processing that is performed on the first side of the first die (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 19, further comprising: forming bonding structures on the first side of the first die; and bonding the first side with a second die before the second processing that is performed on the second side of the first die (figures 4A-4M; [0036-0049]). Nagumo teaches, in claim 20, further comprising: forming a through silicon contact by the second processing that is performed on the second side of the first die, the through silicon contact connecting a punch through contact structure with a pad structure on the second side of the first die (figures 4A-4M; [0036-0049]). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to STANETTA D ISAAC whose telephone number is (571)272-1671. The examiner can normally be reached M-F 10-6. 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, Leonard Chang can be reached at 571-270-3691. 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. /STANETTA D ISAAC/Examiner, Art Unit 2898 January 7, 2026
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Prosecution Timeline

Dec 23, 2021
Application Filed
Mar 23, 2024
Non-Final Rejection — §102
May 28, 2024
Interview Requested
Jun 21, 2024
Applicant Interview (Telephonic)
Jun 21, 2024
Examiner Interview Summary
Jun 28, 2024
Response Filed
Feb 18, 2025
Final Rejection — §102
Apr 24, 2025
Response after Non-Final Action
May 14, 2025
Request for Continued Examination
May 15, 2025
Response after Non-Final Action
Dec 10, 2025
Response Filed
Feb 07, 2026
Non-Final Rejection — §102 (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
86%
Grant Probability
48%
With Interview (-37.9%)
2y 7m
Median Time to Grant
High
PTA Risk
Based on 948 resolved cases by this examiner. Grant probability derived from career allow rate.

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