Prosecution Insights
Last updated: August 18, 2026
Application No. 17/709,628

STACKED FIELD EFFECT TRANSISTORS WITH REDUCED GATE-TO-DRAIN PARASITIC CAPACITANCE

Non-Final OA §102§103
Filed
Mar 31, 2022
Examiner
BOATMAN, CASEY PAUL
Art Unit
2893
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
International Business Machines Corporation
OA Round
3 (Non-Final)
83%
Grant Probability
Favorable
3-4
OA Rounds
0m
Est. Remaining
94%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allowance Rate
63 granted / 76 resolved
+14.9% vs TC avg
Moderate +11% lift
Without
With
+11.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 7m
Avg Prosecution
22 currently pending
Career history
96
Total Applications
across all art units

Statute-Specific Performance

§103
49.8%
+9.8% vs TC avg
§102
28.9%
-11.1% vs TC avg
§112
20.9%
-19.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 76 resolved cases

Office Action

§102 §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 . 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 April 14, 2026 has been entered. Response to Amendment Amendment submitted March 26, 2026 to claim 1 is acknowledged and has since been entered. Cancellation of claim 14 is further acknowledged. Claim Interpretation Claim 1 cites “an inner field effect transistor” and “an outer field effect transistor,” which examiner notes refers to a lower FET and upper FET respectively as specified in paragraph [0045] of the instant application. As such, the terms “inner” and “upper” in relation to each FET and their corresponding components are interpreted to mean “lower” and “upper” respectively. 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) 1-2 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Xie (US 20210265345 A1). Regarding Claim 1, Xie teaches a semiconductor structure (see Fig. 1) comprising: an inner field effect transistor (lower FET, see Fig. 26, see also “lower nanosheets” labeled in Fig. 2) having an inner source (1706), an inner drain (1706), and a group of inner nanosheet channel structures (210’b and 214’b) interconnecting the inner source and the inner drain (shown Fig. 26); an outer field effect transistor (upper FET, shown Fig. 26, see also “upper nanosheets” labeled in Fig. 2) having an outer source (1710), an outer drain (1710), and a group of outer nanosheet channel structures (222’b and 226’b) interconnecting the outer source and the outer drain (shown Fig. 26); an isolation region (1708) between the inner field effect transistor and the outer field effect transistor (shown Fig. 26); a metal gate stack (2002, 2602 and 2604) between the inner source and inner drain and between the outer source and the outer drain (shown Fig. 26), the metal gate stack at least partially surrounding the group of inner nanosheet channel structures and the group of outer nanosheet channel structures (shown Fig. 27, see also [0092] which describes a “gate-all-around” configuration), the metal gate stack having a dielectric region (1502’) adjacent the isolation region; a substrate (202), wherein the inner field effect transistor and the metal gate stack are formed on the substrate (shown Fig. 26); and shallow trench isolation (304) material recessed into the substrate (see Fig. 3 and [0010]) adjacent to the inner source and the inner drain (see Figs. 1 and 26-27, wherein it is understood that the STI extends along a protruding portion of the substrate and is adjacent to lower source and drain 1706). Regarding Claim 2, Xie teaches the semiconductor structure of Claim 1, wherein the inner field effect transistor comprises one of an n-type field effect transistor and a p-type field effect transistor (see [0036]), and wherein the outer field effect transistor comprises another one of an n-type field effect transistor and a p-type field effect transistor (see [0036]). Claim(s) 3-7 and 12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Xie (US 20210265345 A1) and further evidenced by Paul (US 20190214469 A1). Regarding Claim 3, Xie teaches the semiconductor structure of Claim 2, wherein the inner field effect transistor comprises the n-type field effect transistor and the outer field effect transistor comprises the p-type field effect transistor (see [0036]). Paul (US 10418449 B2) being further incorporated by reference in Xie (see [0069]), of which Paul (US 20190214469 A1) is deemed an equivalent disclosure, teaches circuitry based on complementary field-effect transistors, wherein a stacked semiconductor structure further comprises a first electrically conductive pathway (Paul: 88, shown Fig. 14C) coupling an inner drain (38) and an outer drain (46) and forming an output node (shown Paul: Fig. 14C), wherein the metal gate stack includes a side region electrically coupling an inner gate of the inner field effect transistor and an outer gate of the outer field effect transistor and forming an input node (see Paul: Fig. 14D and [0065] which describes the functional gate structures being coupled to a contact in metallization level 92). Regarding Claim 4, Xie teaches the semiconductor structure of Claim 3, further comprising: a first rail (Paul: 96, shown Fig. 14D) electrically coupled to the outer source; and a second rail (Paul: 100, shown Fig. 14D) electrically coupled to the inner source. Regarding Claim 5, Xie teaches the semiconductor structure of Claim 4, further comprising: a plurality of additional p-type inner field effect transistors having a plurality of additional inner sources, a plurality of additional inner drains, and a plurality of additional groups of inner nanosheet channel structures interconnecting the plurality of additional inner sources and the plurality of additional inner drains (shown Fig. 26, see also Xie: [0042] which discloses a number of FETs shown being “merely an example”); a plurality of additional n-type outer field effect transistors having a plurality of additional outer sources, a plurality of additional outer drains, and a plurality of additional groups of outer nanosheet channel structures interconnecting the plurality of additional outer sources and the plurality of additional outer drains (as suggested in Xie: [0042], any number of devices may be implemented to match the exemplary pattern shown in Fig. 26); a plurality of additional metal gate stacks between the plurality of additional inner sources and the plurality of additional inner drains and between the plurality of additional outer sources and the plurality of additional outer drains, the plurality of additional metal gate stacks at least partially surrounding the plurality of additional groups of inner and outer nanosheet channel structures; and a plurality of additional first electrically conductive pathways coupling the plurality of additional inner drains and the plurality of additional outer drains and forming a plurality of additional output nodes (as evidenced by Paul: Fig. 14D and [0032]); and wherein: the isolation region extends between the plurality of additional inner field effect transistors and the plurality of additional outer field effect transistors (shown Xie: Fig. 26), the plurality of additional metal gate stacks each having a dielectric region (1502’) adjacent the isolation region (shown Fig. 26); the plurality of additional outer sources are electrically coupled to the first rail (as evidenced by Paul, see also Fig. 14D and [0065] which describes a first power rail supplying a positive supply voltage, which is understood to be common to any number of implemented transistors within the designed cell); the plurality of additional inner sources are electrically coupled to the second rail (as evidenced by Paul, see also Fig. 14D). Regarding Claim 6, Xie teaches the semiconductor structure of Claim 5, further comprising a power supply coupled to the first rail (see evidenced by Paul: [0065]). Regarding Claim 7, Xie teaches the semiconductor structure of Claim 4, wherein the second rail comprises a buried power rail (shown Paul: Fig. 14D). Regarding Claim 12, Xie teaches the semiconductor structure of Claim 1, further comprising gate spacers (1704) located adjacent the metal gate stack (shown Fig. 26). 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. Claim(s) 8-9 are rejected under 35 U.S.C. 103 as being unpatentable over Xie (US 20210265345 A1). Regarding Claim 8, Xie teaches the semiconductor structure of Claim 1, wherein the dielectric region comprises SiOx, SiC, SiCO or another suitable “material for dielectric spacers” (see Xie: [0065]). Xie further teaches a list of suitable dielectric materials for inner spacers being SiOx, SiC, SiCO or SiN (see [0068]). It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the instant application to implement silicon nitride as the material of the dielectric region of Xie as “[t]he selection of a known material based on its suitability for its intended use [is] … prima facie obviousness” (see also MPEP 2144.07). Regarding Claim 9, Xie teaches the semiconductor structure of Claim 8, wherein the inner and outer nanosheet channel structures comprise silicon (see [0043]). Claim(s) 13 is rejected under 35 U.S.C. 103 as being unpatentable over Xie (US 20210265345 A1) and further evidenced by Paul (US 20190214469 A1). Regarding Claim 13, Xie teaches the semiconductor structure of Claim 12, wherein the dielectric region comprises SiOx, SiC, SiCO or another suitable “material for dielectric spacers” (see Xie: [0065]), and the gate spacers comprise SiOx, SiC, SiCO or SiN (see also [0068]). Xie further teaches a list of suitable dielectric materials for inner spacers being SiOx, SiC, SiCO or SiN (see [0068]) and Paul further teaches a suitable dielectric material for a gate spacer (Paul: 24) being silicon oxycarbonitride (SiOCN) (see also Paul: 0035]). It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the instant application to implement silicon nitride as a material of the dielectric region and SiOCN as a material of the gate spacers of Xie as “[t]he selection of a known material based on its suitability for its intended use [is] … prima facie obviousness” (see also MPEP 2144.07). Claim(s) 10-11 are rejected under 35 U.S.C. 103 as being unpatentable over Xie (US 20210265345 A1) in further view of Singh (US 20130334700 A1). Regarding Claim 10, Xie teaches the semiconductor structure of Claim 1, but does not explicitly teach wherein the dielectric region has a void located therein. Singh teaches a semiconductor device comprising a low-k dielectric layer (221), wherein the low-k dielectric layer further comprises a void (air gap 223, see Singh: [0045]). It would be obvious to one of ordinary skill in the art prior to the effective filing date of the instant application to modify the dielectric region of Xie to further comprise an air gap as suggested by Singh as this may reduce the dielectric constant by 5% or more (see Singh: [0045]) and further provide low capacitance (see Singh: [0048]). Specifically, this modification would teach the dielectric region having a void, wherein the void is an air gap. Regarding Claim 11, Xie as modified by Singh teaches the semiconductor structure of Claim 10, wherein the void comprises an air gap. Response to Arguments Applicant’s arguments with respect to claim 1 has been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to CASEY PAUL BOATMAN whose telephone number is (703)756-4778. The examiner can normally be reached M-F 7:30 AM - 5:30 PM ET. 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, Britt Hanley can be reached at (571)270-3042. 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. /C.P.B./ Examiner, Art Unit 2893 /Britt Hanley/ Supervisory Patent Examiner, Art Unit 2893
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Prosecution Timeline

Show 5 earlier events
Feb 24, 2026
Interview Requested
Mar 03, 2026
Applicant Interview (Telephonic)
Mar 03, 2026
Examiner Interview Summary
Mar 26, 2026
Response after Non-Final Action
Apr 14, 2026
Request for Continued Examination
Apr 22, 2026
Response after Non-Final Action
May 26, 2026
Non-Final Rejection mailed — §102, §103
Aug 06, 2026
Interview Requested

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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
83%
Grant Probability
94%
With Interview (+11.4%)
3y 7m (~0m remaining)
Median Time to Grant
High
PTA Risk
Based on 76 resolved cases by this examiner. Grant probability derived from career allowance rate.

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