Prosecution Insights
Last updated: April 19, 2026
Application No. 18/620,041

METHOD FOR MAKING A HIGH ASPECT RATIO TRENCH

Non-Final OA §102§103§112
Filed
Mar 28, 2024
Examiner
DEO, DUY VU NGUYEN
Art Unit
1713
Tech Center
1700 — Chemical & Materials Engineering
Assignee
STMicroelectronics
OA Round
1 (Non-Final)
82%
Grant Probability
Favorable
1-2
OA Rounds
2y 6m
To Grant
89%
With Interview

Examiner Intelligence

Grants 82% — above average
82%
Career Allow Rate
842 granted / 1023 resolved
+17.3% vs TC avg
Moderate +7% lift
Without
With
+7.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
19 currently pending
Career history
1042
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
44.7%
+4.7% vs TC avg
§102
29.0%
-11.0% vs TC avg
§112
13.7%
-26.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1023 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 . Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claim 20 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 20 depends on itself. It appears that it should depend on claim 16. For the purpose of examination, it is considered to depend on claim 16. 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) 1-3, 11-14 is/are rejected under 35 U.S.C. 102a1 as being anticipated by Satoko et al. (JP 2013206991A). With respect to claims 1, 3, Satoko describes a method comprising: providing a silicon semiconductor substrate 102 having an upper surface; forming a trench extending into the substrate 102 by using two processes. The first process or claimed a first etch phase, including a Bosch process of a plurality of cycles of alternating etching and depositing steps to open a first portion of the trench having a first depth (page 2, 3; fig. 1, 2), PNG media_image1.png 270 286 media_image1.png Greyscale PNG media_image2.png 128 314 media_image2.png Greyscale . The second process, or claimed second etch phase, subsequent to the first etch phase using reactive ion etch wherein “in a reactive ion etching apparatus using inductively coupled plasma, plasma can be formed at a low pressure. At a low pressure, the mean free path of etching molecules becomes long, so that etching gas molecules can reach the back of the fine pattern, and anisotropic etching of the silicon substrate 102 with respect to the opening diameter of the mask 101 becomes possible. For this reason, the scallops on the sidewalls of the trenches and vias are scraped off, and a silicon substrate 102 having trenches or vias without scallops as shown in FIG. 4 is obtained. Further, the corners of the opening401 and the bottom 402 of the trench and via are rounded” (page 3, fig. 3) and “etching depth and opening diameter are increased by increasing pressure.” (page 5). This provide claimed second phase process to extend from a bottom of the first portion of the trench having a second depth. PNG media_image3.png 134 302 media_image3.png Greyscale With respect to claim 2, Satoko further teaches “an insulating film that avoids interference between the silicon substrate and the TSV is formed on the inner wall, and then a conductor is filled.” (page 2). With respect to claims 11-14, Satoko describe a necessary trench depth is on the order of several to several hundred um (page 2) and fig. 5 shows several trenches or claimed first and second trench having a width of less than 2 um. This would provide trenches with an aspect ratio of at least 10:1. Fig. 5 also shows several trenches including a second trench are simultaneously formed from the first and second etching process, which would provide claimed first and second portion of the second trench with respective first and second depth. PNG media_image4.png 338 368 media_image4.png Greyscale 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) 4, 6, 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Satoko as applied to claim 1 above. With respect to claims 4, 6, Satoko doesn’t describe applying a negative bias voltage to the substrate during the second process. However, he describes second process using a noble gas of He with a bias power of 100W (page 4). According to the instant specification, para 22 describes “during the RIE process, a negative bias voltage is be applied to the substrate 124. As an example, the negative bias voltage may be in the range of 200-400 Volts (which corresponds to a bias power greater than about 100 watts, preferably greater than about 120 watts, and preferably less than about 160 watts)”. Since the bias power is the same as that of the claimed invention, it would have been obvious and within the knowledge of one skilled in the art before the effective filing date of the invention to apply a negative bias voltage in a range such as 200-400 V as long as it can provide a bias power of 100W as suggested by Satoko for the second etching process with expected results. With respect to claim 7, Satoko doesn’t disclose the second process uses a mixture of SF6, O2 and Ar. However, he discloses that this mixture is used in the Bosch process of the first process and he further teaches using fluorine gas for the second process (page 4). Therefore, one skilled in the art would find it obvious to use such mixture in the second process because such mixture is expected to facilitate the second etching process to reduce the scallops or unevenness on the inner wall and extending the depth with expected results. Claim(s) 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Satoko as applied to claim 4 above, and further in view of Wang (US 2021/0265487). With respect to claim 5, even though Satoko doesn’t describe the noble gas is Ar for the second process. However, he teaches using a noble gas of He for the second process. He further discloses noble gas Ar in the Bosch process (page 4). Noble gases including He, and Ar are known as diluted or carrier gas for a plasma etch as shown here by Wang (para 33). Therefore, it would have been obvious to one skilled in the art before the effective filing date of the invention to use Ar for Satoko’s second process, in light of Wang’s teaching, because either Ar or He would provide a dilute or carrier gas for the second process with expected results. Claim(s) 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Satoko as applied to claim 12 above, and further in view of Junshi et al. (JP 2010103358A). With respect to claim 15, Satoko doesn’t teach the trenches have different depth. However, such structures are known and practiced by one skilled in the art as shown here by Junshi, who teaches a method for forming trenches having different depth with the same fluorine containing plasma of SF6. The depth of a trench is largely depending on its width with the etching increases as the width of the trench increases (page 2; fig. 1f, 1g) PNG media_image5.png 276 196 media_image5.png Greyscale . It would have been obvious to one skilled in the art to provide a structure with trenches having different depth in light of Junshi because it is a known structure and the type of structure would depends on the type of semiconductor device being manufactured. Allowable Subject Matter Claims 8, 9, 10 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. With respect to claim 8, Satoko doesn’t teach in the second process, the gas mixture comprise 35-55% SF6, 25-40% O2, and 15-30% Ar. With respect to claim 9 and its dependent claim 10, Satoko doesn’t teach performing the second process or claimed the reactive ion etch comprises an initial phase including flowing that gas mixture that includes CHF3, O2 and Ar but where no plasma power is applied. Claims 16-20 are allowed because the combined prior art Satoko and Junshi, while describe a method for etching different trenches with different depth and lining the trenches with insulating layer and conductive material; however, neither suggests lining sidewalls and bottom of each of the trenches with an insulating layer, removing the insulating layer from the bottom of a second trench, while leaving the insulating layer in place on the bottom of the first trench; and then filling each of the first and second trenches with a conductive material. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DUY VU NGUYEN DEO whose telephone number is (571)272-1462. The examiner can normally be reached 9-5 M-F. 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, Joshua Allen can be reached at 571-272-3176. 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. /DUY VU N DEO/Primary Examiner, Art Unit 1713 2/27/2026
Read full office action

Prosecution Timeline

Mar 28, 2024
Application Filed
Feb 27, 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
82%
Grant Probability
89%
With Interview (+7.1%)
2y 6m
Median Time to Grant
Low
PTA Risk
Based on 1023 resolved cases by this examiner. Grant probability derived from career allow rate.

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