Prosecution Insights
Last updated: April 19, 2026
Application No. 18/472,343

BURIED SHIELD STRUCTURES FOR POWER SEMICONDUCTOR DEVICES INCLUDING SEGMENTED SUPPORT SHIELD STRUCTURES FOR REDUCED ON-RESISTANCE AND RELATED FABRICATION METHODS

Non-Final OA §102§103§112
Filed
Sep 22, 2023
Examiner
RAHMAN, MOHAMMAD A
Art Unit
2898
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Wolfspeed, Inc.
OA Round
1 (Non-Final)
86%
Grant Probability
Favorable
1-2
OA Rounds
2y 9m
To Grant
98%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
459 granted / 531 resolved
+18.4% vs TC avg
Moderate +12% lift
Without
With
+11.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
27 currently pending
Career history
558
Total Applications
across all art units

Statute-Specific Performance

§101
2.2%
-37.8% vs TC avg
§103
45.9%
+5.9% vs TC avg
§102
31.1%
-8.9% vs TC avg
§112
18.9%
-21.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 531 resolved cases

Office Action

§102 §103 §112
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 . DETAILED ACTION Claims 1-23, 27, 29-32 are pending and have been examined. Priority Acknowledgment is made that the instant application is a continuation in part of US patent application 18150432 filed on 09/22/2023. Claim Rejections - 35 USC § 102 The following is a quotation of 35 U.S.C. 102(a)(1) that forms the basis for the rejection set forth in this Office action: (a) NOVELTY; PRIOR ART.—A person shall be entitled to a patent unless— (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; Notes: when present, semicolon separated fields within the parenthesis (; ;) represent, for example, as (30A; Fig 2B; [0128]) = (element 30A; Figure No. 2B; Paragraph No. [0128]). For brevity, the texts “Element”, “Figure No.” and “Paragraph No.” shall be excluded, though; additional clarification notes may be added within each field. The number of fields may be fewer or more than three indicated above. These conventions are used throughout this document. Claims 1-2, 14-16, 18-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kim et al. (US 20220149196 A1 – hereinafter Kim). Regarding Claim 1, Kim teaches a semiconductor device (see the entire document; Fig. 1A; specifically, ([0062] - [0063]), and as cited below), comprising: a semiconductor layer structure (106 – Fig. 1A – [0062]) comprising a drift region (120) of a first conductivity type ([0062] – “n-type drift region 120”) and a well region (170) of a second conductivity type ([0062] – “P-wells 170”) above the drift region (120); a gate (184 – [0063]) on the semiconductor layer structure adjacent the well region (170); and a contact shielding structure (left 140a, right 140a) of the second conductivity type (p-type – [0062]) that vertically extends from the well region (170) into the drift region (120) and discontinuously extends in one or more lateral directions (Fig. 1A shows left 140a and right 140a extends separately [discontinuously] in the x-direction). Regarding Claim 2, Kim teaches the semiconductor device of Claim 1, wherein the contact shielding structure comprises a plurality of discrete segments (left 140a, right 140a) that extend in the one or more lateral directions (x-directions), respectively. Regarding Claim 14, Kim teaches the semiconductor device of Claim 2, wherein respective spacings between the discrete segments are aligned along a direction crossing the one or more lateral directions. Regarding Claim 15, Kim teaches the semiconductor device of Claim 2, wherein respective spacings between the discrete segments (left 140a, right 140a) are staggered along a direction (x-direction) crossing the one or more lateral directions (x-direction). Regarding Claim 16, Kim teaches the semiconductor device of Claim 2, wherein respective spacings between the discrete segments are less than respective widths of the discrete segments (Fig. 1A appears to teach the claimed limitation). Regarding Claim 18, Kim teaches the semiconductor device of Claim 2, wherein the semiconductor layer structure further comprises: a substrate (110 – [0062]), wherein the drift region (120) is on the substrate (110); and a drain contact (192 – [0062]) on the substrate (110) opposite the drift region (120), wherein respective spacings between the discrete segments comprise portions of the semiconductor layer structure that are free of the contact shielding structure (see Fig. 1A). Regarding Claim 19, Kim teaches the semiconductor device of Claim 18, wherein the semiconductor layer structure further comprises a source region (160 – [0064]) of the first conductivity type (n-type) above the well region (170), and further comprising: a source contact (190a) on a surface of the semiconductor layer structure opposite the drain contact (192), wherein the source contact is electrically coupled to the source region and the contact shielding structure (as seen in Fig. 1A). Regarding Claim 20, Kim teaches the semiconductor device of Claim 1, wherein the contact shielding structure comprises a material and/or dopant concentration that is different from that of the drift region (since contact shielding is p-type and the drift layer if n-type). 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. Notes: when present, semicolon separated fields within the parenthesis (; ;) represent, for example, as (30A; Fig 2B; [0128]) = (element 30A; Figure No. 2B; Paragraph No. [0128]). For brevity, the texts “Element”, “Figure No.” and “Paragraph No.” shall be excluded, though; additional clarification notes may be added within each field. The number of fields may be fewer or more than three indicated above. These conventions are used throughout this document. Claims 17, 29-30 are rejected under 35 U.S.C. 103 as being unpatentable over Kim. Regarding Claim 17, Kim teaches claim 16 from which claim 17 depends. But Kim does not expressly disclose wherein the respective widths of the discrete segments are between about 0.1 and about 20 microns. The instant application specification contains no disclosure of either the critical nature of the claimed relative width i.e., “wherein the respective widths of the discrete segments are between about 0.1 and about 20 microns” or of any unexpected results arising therefrom. Applicant has not disclosed that having wherein the respective widths of the discrete segments are between about 0.1 and about 20 microns, solves any stated problem or is for any particular purpose. "Where the issue of criticality is involved, the applicant has the burden of establishing his position by a proper showing of the facts upon which he relies." - In re Scherl, 156 F.2d 72, 74-75, 70 USPQ 204, 205 (CCPA 1946), see MPEP 2144.05.III.A. Regarding Claim 29, Kim teaches a semiconductor device (see the entire document; Fig. 1A; specifically, ([0062] - [0063]), and as cited below), comprising: a semiconductor layer structure (106 – Fig. 1A – [0062]) comprising a drift region (120) of a first conductivity type ([0062] – “n-type drift region 120”) and a well region (170) of a second conductivity type ([0062] – “P-wells 170”) above the drift region; (120) a gate (184 – [0063]) on the semiconductor layer structure adjacent the well region (170); and a contact shielding structure (left 140a, right 140a) of the second conductivity type (p-type – [0062]) that vertically extends from the well region into the drift region (120) and comprises a plurality of segments with respective spacings therebetween (Fig. 1A shows left 140a and right 140a extends separately [discontinuously] in the x-direction). But Kim does not expressly disclose wherein the respective spacings are smaller than respective widths of the segments. The instant application specification contains no disclosure of either the critical nature of the claimed relative spacings i.e., “wherein the respective spacings are smaller than respective widths of the segments” or of any unexpected results arising therefrom. Applicant has not disclosed that having wherein the respective spacings are smaller than respective widths of the segments, solves any stated problem or is for any particular purpose. "Where the issue of criticality is involved, the applicant has the burden of establishing his position by a proper showing of the facts upon which he relies." - In re Scherl, 156 F.2d 72, 74-75, 70 USPQ 204, 205 (CCPA 1946), see MPEP 2144.05.III.A. Regarding claim 30, Kim teaches claim 30 from which claim 30 depends. But Kim does not expressly disclose wherein the respective widths of the segments are about 0.1 microns to about 20 microns. The instant application specification contains no disclosure of either the critical nature of the claimed relative widths i.e., “wherein the respective widths of the segments are about 0.1 microns to about 20 microns” or of any unexpected results arising therefrom. Applicant has not disclosed that having wherein the respective widths of the segments are about 0.1 microns to about 20 microns, solves any stated problem or is for any particular purpose. "Where the issue of criticality is involved, the applicant has the burden of establishing his position by a proper showing of the facts upon which he relies." - In re Scherl, 156 F.2d 72, 74-75, 70 USPQ 204, 205 (CCPA 1946), see MPEP 2144.05.III.A. Allowable Subject Matter Claims 3-13, 31-32 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. The following is the Examiner’s Reasons for Allowance: The prior art fails to disclose and would not have rendered obvious: Regarding claim 3: The semiconductor device of Claim 2, wherein the contact shielding structure comprises support shielding structures that extend in a first lateral direction and are spaced apart from the gate. Claims 4-13 depend from claim 3. Regarding claim 31: The semiconductor device of Claim 29, wherein the semiconductor device has an avalanche capability that is increased by about 5% to about 30% and an on- resistance that is reduced by about 5% to about 30%, in comparison to a semiconductor device having a continuous shielding pattern. Claim 32 depends from claim 31. REASON FOR ALLOWANCE Claims 21-23, 27 are allowed over prior art. The following is an examiner’s statement of reasons for allowance, which paraphrases and summarizes the claimed invention without intending to be limiting, wherein the legally defined scope of the claimed invention is defined by the allowed claims themselves in view of the written description under 35 USC 112. This statement is not intended to necessarily state all the reasons for allowance or all the details why the claims are allowed and has not been written to specifically or impliedly state that all the reasons for allowance are set forth (MPEP 1302.14). Regarding claim 21, the reference(s) of the Prior Art of record and considered pertinent to the applicant's disclosure and to the examiner’s knowledge do(es) not teach or render obvious, at least to the skilled artisan, the instant invention regarding a method in their entirety (the individual limitations may be found just not in combination with proper motivation). The most relevant prior art reference(s) (US 20220149196 A1 to Kim) substantially teach(es) some of limitations in claim 21 as shown in the rejection of claim, but not the limitations of “a support shielding structure of the second conductivity type that vertically extends from the well region into the drift region and is spaced apart from the gate; and a bridge shielding structure of the second conductivity type that laterally extends from the support shielding structure towards the gate, wherein at least one of the support shielding structure or the bridge shielding structure comprises a plurality of discrete segments” as recited in claim 21. Therefore, the claim 21 is deemed patentable over the prior art. Regarding claims 22-23, 27, they are allowed due to their dependencies on claim 21. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to MOHAMMAD A. RAHMAN whose telephone number is (571) 270-0168 and email is mohammad.rahman5@uspto.gov. The examiner can normally be reached on Mon-Fri 8:00-5:00 PM. 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, Julio J. Maldonado can be reached on (571) 272-1864. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see https://ppair-my.uspto.gov/pair/PrivatePair. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /MOHAMMAD A RAHMAN/ Primary Examiner, Art Unit 2898
Read full office action

Prosecution Timeline

Sep 22, 2023
Application Filed
Feb 07, 2026
Non-Final Rejection — §102, §103, §112 (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
86%
Grant Probability
98%
With Interview (+11.7%)
2y 9m
Median Time to Grant
Low
PTA Risk
Based on 531 resolved cases by this examiner. Grant probability derived from career allow rate.

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