Prosecution Insights
Last updated: July 17, 2026
Application No. 17/657,428

BACKSIDE METALLIZATION FOR SEMICONDUCTOR ASSEMBLY

Non-Final OA §103
Filed
Mar 31, 2022
Priority
Dec 02, 2021 — provisional 63/285,247
Examiner
KHALIFA, MOATAZ
Art Unit
2817
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Qorvo US Inc.
OA Round
6 (Non-Final)
92%
Grant Probability
Favorable
6-7
OA Rounds
0m
Est. Remaining
91%
With Interview

Examiner Intelligence

Grants 92% — above average
92%
Career Allowance Rate
54 granted / 59 resolved
+23.5% vs TC avg
Minimal -0% lift
Without
With
+-0.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
37 currently pending
Career history
108
Total Applications
across all art units

Statute-Specific Performance

§103
93.6%
+53.6% vs TC avg
§102
1.9%
-38.1% vs TC avg
§112
2.9%
-37.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 59 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 . Continued Examination Under 35 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 02/03/2026 has been entered. Remarks The 01/29/2026 amendments of claims 1, 10 and 18 have been noted an entered. The 01/29/2026 cancellation of claim 7 has been noted and entered. Response to Arguments Applicant’s arguments, see Remarks pages 5-8, filed 01/29/2026, with respect to the rejection(s) of claim(s) 1-18 and 20-21 under 35 U.S.C. 103 have been fully considered and are persuasive in light of the newly added amendments. However, upon further consideration, a new grounds of rejection is made in view of Chu et al, US 5168348 A (Chu). New grounds of Rejection New grounds of rejection, prior art reference Chu et al, US 5168348 A (Chu) appears below. 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. Rejection Note: Italicized claim limitations indicate limitations that are not explicitly disclosed in the primary reference, but disclosed in the secondary reference(s). Claims 1-5, 8, 14-18 and 20-21 are rejected under 35 U.S.C. 103 as being unpatentable over Combs, US 6552417 B2 (Combs) in view of Chu et al, US 5168348 A (Chu) in further view of Lidow et al, US 20100258844 A1 (Lidow). Regarding claim 1; Combs teaches a semiconductor assembly (Combs: Fig (2): 200) comprising: a die comprising a substrate (211); and a metallization layer (201) patterned on a planar surface of the substrate (211), wherein the metallization layer (201) is configured to act as a ground plane (Column: 3 Rows: 12-17: “For an electrically isolated section of the interposer ring, an electrical short to the heat sink allows the heat sink to be used as a ground plane for the semiconductor die.”) for electrical elements within the die (211), and the metallization layer comprises at least one trench that extends through the metallization layer to the planar surface of the substrate and is within a boundary of the metallization layer, wherein the boundary of the metallization layer does not extend past an edge of the planar surface of the substrate. PNG media_image1.png 623 894 media_image1.png Greyscale Combs does not teach the metallization layer comprises at least one trench that extends through the metallization layer to the planar surface of the substrate and is within a boundary of the metallization layer. Chu teaches the metallization layer (Chu: Annotated Fig (17) shared in this OA: 115) comprises at least one trench (trench) that extends through the metallization layer (115) to the planar surface of the substrate (Substrate, 102) and is within a boundary of the metallization layer (115). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to construct the trenches in the metallization layer to extend through the entire metallization layer to the planar surface of the substrate as disclosed in Chu to increase the flexibility of the metallization layer and thus its resistance to thermally induced stresses leading to a more reliable device. PNG media_image2.png 762 677 media_image2.png Greyscale Combs in view of Chu does not teach wherein the boundary of the metallization layer does not extend past an edge of the planar surface of the substrate. Lidow teaches wherein the boundary of the metallization layer (Lidow: Fig (4): 19) does not extend past an edge of the planar surface of the substrate (12). Combs in view of Chu and Lidow are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu by constructing the metallization layer such that it does not extend past an edge of the planar surface of the substrate as disclosed in Lidow to reduce the footprint of the device leading to higher density of components in the device leading to a more efficient and higher performing device. PNG media_image3.png 632 878 media_image3.png Greyscale Regarding claim 2; Combs in view Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. Further, Combs teaches wherein the metallization layer (Combs: Fig (2): 201) comprises gold (Au), copper (Cu) (Column: 2 Lines: 62-65 ad column: 3 Lines: 1-3), silver (Ag), nickel (Ni), platinum (Pt), titanium (Ti), chromium (Cr), Tungsten (W), or a combination of these materials. Regarding claim 3; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. However, Combs does not teach wherein the at least one trench comprises a plurality of trenches arranged in a rectilinear fashion. Chu teaches wherein the at least one trench (Chu: Annotated Fig (17): Trench) comprises a plurality of trenches arranged in a rectilinear fashion. Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs by using the structure of the trenches disclosed by Chu to improve the stress resistance of the metallization layer leading to a more reliable device. Regarding claim 4; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 3. However, Combs in view of Chu does not teach wherein the plurality of trenches is uniformly distributed with a constant pitch. Lidow teaches wherein the plurality of trenches (Lidow: Fig (4): pitches of 19) is uniformly distributed with a constant pitch. Combs in view of Chu and Lidow are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu by using the structure of the trenches disclosed by Lidow to improve the stress resistance of the metallization layer leading to a more reliable device. Regarding claim 5; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 3. However, Combs does not teach wherein the plurality of trenches is non- uniformly distributed with a non-constant pitch. Chu teaches wherein the plurality of trenches (Chu: Annotated Fig (17) shared in this OA: Trenches of 115) is non- uniformly distributed with a non-constant pitch. Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs by introducing the non-uniform distribution of the trenches in the metallization layer as disclosed in Chu to increase the stress reduction function of the metallization layer. Regarding claim 8; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. However, Combs in view of Chu does not teach wherein the at least one trench only partially extends through the metallization layer leaving a fill. Lidow teaches wherein the at least one trench (Lidow: Fig (4): trenches of 19) only partially extends through the metallization layer (19) leaving a fill. Combs in view of Chu and Lidow are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu by having the trench only partially go through the metallization layer as disclosed in Lidow to improve the integrity of the device against mechanical stress while offering more metallic material to help dissipate more heat from the device leading to a more reliable device. Regarding claim 14; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. However, Combs does not teach wherein the at least one trench comprises a plurality of trenches arranged in a cross and x fashion to form triangular portions in the metallization layer. Chu teaches wherein the at least one trench comprises a plurality of trenches (Chu: Fig (12): 1202) arranged in a cross and x fashion to form triangular portions in the metallization layer (115). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs by using the trenches arranged in a cross and x fashion as disclosed in Chu to improve the heat dissipation performance of the back metallization layer leading to a more reliable device. PNG media_image4.png 843 566 media_image4.png Greyscale Regarding claim 15; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. Further, Combs teaches further comprising a lead frame (Combs: Fig (2): 205) attached to the metallization layer (201). Regarding claim 16; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. Further, Combs teaches wherein the metallization layer (Combs: Fig (2): 201) is formed on the backside. Regarding claim 17; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. Further, Combs teaches wherein the metallization layer (Combs: Fig (2): 201) is attached to the backside. Regarding claim 18; Combs teaches a computing device comprising: a semiconductor assembly (Combs: Fig (2): 200) comprising: a die comprising a substrate (211), wherein the die (211) comprises at least one circuit used by the computing device; and a metallization layer (201) patterned on a planar surface of the substrate (211), wherein the metallization layer (201) is configured to act as a ground plane (Column: 3 Rows: 12-17: “For an electrically isolated section of the interposer ring, an electrical short to the heat sink allows the heat sink to be used as a ground plane for the semiconductor die.”) for electrical elements within the die (211), and the metallization layer comprises at least one trench that extends through the metallization layer to the planar surface of the substrate within a boundary of the metallization layer, wherein the boundary of the metallization layer does not extend past an edge of the planar surface of the substrate. Combs does not teach the metallization layer comprises at least one trench that extends through the metallization layer to the planar surface of the substrate and is within a boundary of the metallization layer. Chu teaches the metallization layer (Chu: Annotated Fig (17) shared in this OA: 115) comprises at least one trench (trench) that extends through the metallization layer (115) to the planar surface of the substrate (Substrate, 102) and is within a boundary of the metallization layer (115). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to construct the trenches in the metallization layer to extend through the entire metallization layer to the planar surface of the substrate as disclosed in Chu to increase the flexibility of the metallization layer and thus its resistance to thermally induced stresses leading to a more reliable device. Combs in view of Chu does not teach wherein the boundary of the metallization layer does not extend past an edge of the planar surface of the substrate. Lidow teaches wherein the boundary of the metallization layer (Lidow: Fig (4): 19) does not extend past an edge of the planar surface of the substrate (12). Combs in view of Chu and Lidow are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu by constructing the metallization layer such that it does not extend past an edge of the planar surface of the substrate as disclosed in Lidow to reduce the footprint of the device leading to higher density of components in the device leading to a more efficient and higher performing device Regarding claim 20; Combs in view of Chu in further view of Lidow teaches all the limitations of the computing device of claim 18. However, Combs does not teach wherein the at least one trench comprises a plurality of trenches arranged with at least one arcuate segment and wherein the at least one arcuate segment comprises a plurality of concentric circles. Chu teaches wherein the at least one trench comprises a plurality of trenches (Chu: Fig (11): 1102) arranged with at least one arcuate segment and wherein the at least one arcuate segment comprises a plurality of concentric circles (1102). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs to construct the arcuate segment to comprise a plurality of concentric circles as disclosed in Chu to improve the heat dissipation function of the metallization layer leading to a more reliable device. Regarding claim 21; Combs in view of Chu in further view of Lidow teaches all the limitations of claim 18. However, Combs does not teach wherein the at least one trench comprises a plurality of trenches arranged in a cross and x fashion to form triangular portions in the metallization layer. Chu teaches wherein the at least one trench (Chu: Fig (12): 1202) comprises a plurality of trenches (1202) arranged in a cross and x fashion to form triangular portions in the metallization layer (115). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs by using the trenches arranged in a cross and x fashion as disclosed in Chu to improve the heat dissipation performance of the back metallization layer leading to a more reliable device. Claims 6, 9 and 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Combs, US 6552417 B2 (Combs) in view of Chu et al, US 5168348 A (Chu) in further view of Lidow et al, US 20100258844 A1 (Lidow) in further view of Grillberger et al, CN 102132406 A (Grillberger) Regarding claim 6; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 3. However, Combs in view of Chu in further view of Lidow does not teach wherein the plurality of trenches comprises rounded corners for intersections of the plurality of trenches. Grillberger teaches wherein the plurality of trenches (Grillberger: Fig (2b): 280) comprises rounded corners for intersections of the plurality of trenches (280). Combs in view of Chu in further view of Lidow and Grillberger are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu in further view of Lidow by introducing the rounded corners as disclosed in Grillberger to improve the heat dissipation from the metallization layer by increasing the surface area of the layer leading to a more reliable device. PNG media_image5.png 564 460 media_image5.png Greyscale Regarding claim 9; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. However, Combs in view of Chu in further view of Lidow does not teach wherein the at least one trench comprises a plurality of trenches arranged with at least one arcuate segment. Grillberger teaches wherein the at least one trench (Grillberger: Fig (2b): 280) comprises a plurality of trenches (280) arranged with at least one arcuate segment. Combs in view of Chu in further view of Lidow and Grillberger are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu in further view of Lidow by introducing the segment of trenches with an arcuate segment as disclosed in Grillberger to improve the heat dissipation from the metallization layer by increasing the surface area of the layer leading to a more reliable device. Regarding claim 11; Combs in view of Chu in further view of Grillberger teaches all the limitations of the semiconductor assembly of claim 9. However, Combs does not teach wherein the at least one arcuate segment comprises a plurality of concentric circles. Chu teaches wherein the least one arcuate segment (Chu: Fig (11): 1102) comprises a plurality of concentric circles (1102). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs to construct the arcuate segment to comprise a plurality of concentric circles as disclosed in Chu to improve the heat dissipation function of the metallization layer leading to a more reliable device. Regarding claim 12; Combs in view of Chu in further view of Lidow in further view of Grillberger teaches all the limitations of the semiconductor assembly of claim 9. However, Combs does not teach wherein the plurality of trenches also includes a linear segment. Chu teaches wherein the plurality of trenches (Chu: Fig (17): Trench) also includes a linear segment. Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs by introducing the linear segments of the trenches in the metallization layer as disclosed in Chu to improve the protection of the layer against thermally induced stresses. Claims 13 are rejected under 35 U.S.C. 103 as being unpatentable over Combs, US 6552417 B2 (Combs) in view of Chu et al, US 5168348 A (Chu) in further view of Lidow et al, US 20100258844 A1 (Lidow) in further view of Bodea et al, CN 110473851 A (Bodea). Regarding claim 13; Combs in view of Chu in further view of Lidow teaches all the limitations of the semiconductor assembly of claim 1. However, Combs in view of Chu in further view of Lidow does not teach wherein the metallization layer is at least one-tenth of a micrometer (0.1 µm) thick. Bodea teaches wherein the metallization layer (Bodea: Fig (12): 104) is at least one-tenth of a micrometer (0.1 µm) (see Page: 11 Lines: 28-29 of the translated copy of Bodea attached to this OA where it discloses: “height or thickness (H) of the stress mitigating layer or layer stack 104 may be, for example, in the range of about 6 to 11μm”). Combs in view of Chu in further view of Lidow and Bodea are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu in further view of Lidow by introducing the thickness limitation of the metallization layer as disclosed in Bodea to enhance the stress absorption and heat dissipation abilities of the metallization layer. PNG media_image6.png 434 676 media_image6.png Greyscale Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Combs, US 6552417 B2 (Combs) in view of Chu et al, US 5168348 A (Chu) in further view of Jia et al, “Heat Transfer and Fluid Flow Characteristics of Microchannel with Oval-Shaped Micro Pin Fins” Entropy 2021, 23, 1482. https://doi.org/10.3390/e23111482. Regarding claim 10; Combs teaches a semiconductor assembly (Combs: Fig (2): 200) comprising: a die (211) comprising a substrate (211); and a metallization layer (201) patterned on a planar surface of the substrate (211), wherein the metallization layer comprises at least one trench that extends through the metallization layer to the planar surface of the substrate and is within a boundary of the metallization layer, wherein the boundary of the metallization layer does not extend past an edge of the planar surface of the substrate, wherein the at least one trench comprises a plurality of trenches arranged with at least one arcuate segment, and the at least one arcuate segment comprises an oval. Combs does not teach the metallization layer comprises at least one trench that extends through the metallization layer to the planar surface of the substrate and is within a boundary of the metallization layer. Chu teaches the metallization layer (Chu: Annotated Fig (17) shared in this OA: 115) comprises at least one trench (trench) that extends through the metallization layer (115) to the planar surface of the substrate (Substrate, 102) and is within a boundary of the metallization layer (115). Combs and Chu are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to construct the trenches in the metallization layer to extend through the entire metallization layer to the planar surface of the substrate as disclosed in Chu to increase the flexibility of the metallization layer and thus its resistance to thermally induced stresses leading to a more reliable device. Combs in view of Chu does not teach wherein the boundary of the metallization layer does not extend past an edge of the planar surface of the substrate. Lidow teaches wherein the boundary of the metallization layer (Lidow: Fig (4): 19) does not extend past an edge of the planar surface of the substrate (12). Combs in view of Chu and Lidow are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu by constructing the metallization layer such that it does not extend past an edge of the planar surface of the substrate as disclosed in Lidow to reduce the footprint of the device leading to higher density of components in the device leading to a more efficient and higher performing device Combs in view of Chu does not teach wherein the at least one trench comprises a plurality of trenches arranged with at least one arcuate segment the at least one arcuate segment comprises an oval. Jia teaches wherein the at least one trench comprises a plurality of trenches (Jia: Fig (3)) arranged with at least one arcuate segment, and the at least one arcuate segment comprises an oval (Fig (3)). Combs in view of Chu and Jia are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art, to modify Combs in view of Chu by making a plurality of the trenches arranged with at least one arcuate segment comprising an oval as disclosed in Jia to improve the heat flow from the metallization layer leading to a more reliable device. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Moataz Khalifa whose telephone number is (703)756-1770. The examiner can normally be reached Monday - Friday (8:30 am - 5:00). 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, Kretelia Graham can be reached at (571) 272-5055. 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. /M.K./Examiner, Art Unit 2817 /Kretelia Graham/Supervisory Patent Examiner, Art Unit 2817
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Prosecution Timeline

Show 8 earlier events
Apr 02, 2025
Response Filed
Aug 05, 2025
Non-Final Rejection mailed — §103
Nov 04, 2025
Response Filed
Nov 28, 2025
Final Rejection mailed — §103
Jan 29, 2026
Response after Non-Final Action
Feb 03, 2026
Request for Continued Examination
Feb 10, 2026
Response after Non-Final Action
Jun 05, 2026
Non-Final Rejection mailed — §103 (current)

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Prosecution Projections

6-7
Expected OA Rounds
92%
Grant Probability
91%
With Interview (-0.4%)
3y 4m (~0m remaining)
Median Time to Grant
High
PTA Risk
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