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 .
Election/Restrictions
Applicant’s election without traverse of claims 1-6 in the reply filed on 7/14/2026 is acknowledged.
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 4/15/2024 and 8/25/2026 are in compliance with time for filing requirements of 37 C.F.R. 1.97, and thus, the information disclosure statement has been considered except as otherwise indicated.
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description:
Fig. 11: element 1152
Fig. 5: element 510.
Corrected drawing sheets in compliance with 37 CFR 1.121(d), or amendment to the specification to add the reference character(s) in the description in compliance with 37 CFR 1.121(b) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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.
Claims 3, 25, and 28 are 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.
The terms “about” in claim 25 and “substantially” in claims 3 and 28 are relative terms which renders the claims indefinite. The terms “about” and “substantially” are not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The limitation "an aspect ratio characterizing a maximum width...and a minimum width...is about 3:1" Furthermore, the limitation “the tab is substantially symmetric about…” in claims 3 and 28 is indefinite because it is unclear to what degree, if any, the tab qualifies as symmetric.
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.
Claims 1-6, 21-22, 24, 27-33 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Wu et al. (US20190006512A1).
Regarding Claim 1:
Wu discloses an apparatus (Fig. 2) comprising:
a trench (element 220) having a first portion (element 205) in an active area [ACTIVE] and a second portion (element D1) in a termination region [TERMINATION], the trench having a vertical depth [D] within a semiconductor substrate (Figs. 3 element 320) and having a longitudinal axis [L] extending from within the active area into the termination region (paragraph 25-26);
a dielectric lining (Figs. 3 element 330) disposed in the trench (paragraph 35); and
a conductive electrode (element 340b) disposed in the trench over the dielectric lining (Fig. 3C), the conductive electrode having, along the longitudinal axis [L], a uniform shape within the first portion, and a tapered shape within the second portion (Fig. 2 element 220 and 3C-3C line).
Regarding Claim 2:
Wu discloses an apparatus according to claim 1, further comprising a tab (Fig. 7C element 760c2) intersecting an end of the second portion, the tab extending in a direction transverse to the longitudinal axis (W; paragraph 54).
Regarding Claim 3:
Wu discloses an apparatus according to claim 2, wherein the tab (Fig. 7C-D elements 760c2) is substantially symmetric about the longitudinal axis (paragraphs 54-56).
Regarding Claim 4:
Wu discloses an apparatus according to claim 1, wherein the conductive electrode (Fig. 2 element 220) includes polysilicon (paragraph 37).
Regarding Claim 5:
Wu discloses an apparatus according to claim 1, wherein the semiconductor substrate (Figs. 3 element 320) includes silicon carbide (paragraph 80).
Regarding Claim 6:
Wu discloses an apparatus according to claim 1, being a shield structure of a shielded gate metal oxide semiconductor field effect transistor (paragraphs 15, 25, and 59).
Regarding Claim 21:
Wu discloses an apparatus according to claim 6, wherein the semiconductor substrate (Figs. 3 element 320) includes a diffusion region (ACTIVE; element 370), and wherein the shield structure extends out from within the diffusion region and tapers to a terminus (Fig. 2 element 220 and 3C-3C line).
Regarding Claim 22:
Wu discloses an apparatus according to claim 21, wherein the terminus is a point (Figs. 2 and 7A).
Regarding Claim 24:
Wu discloses an apparatus according to claim 21, wherein the diffusion region (ACTIVE; Figs. 3 element 370), includes a source electrode (element 360) and a drain electrode (paragraph 18).
Regarding Claim 27:
Wu discloses an apparatus (Fig. 2) comprising:
a trench (element 220) in a semiconductor substrate (Figs. 3 element 320), the trench including a first portion (element 205) in an active area [ACTIVE] and a second portion (element D1) in a termination region [TERMINATION], the trench having a longitudinal axis [L] extending from within the active area into the termination region (paragraph 25-26);
a dielectric lining (Figs. 3 element 330) disposed in the trench (paragraph 35);
a conductive electrode (element 340b) disposed in the trench over the dielectric lining (Fig. 3C); and
a tab intersecting an end of the second portion (Fig. 7C element 760c2), the tab extending in a direction transverse to the longitudinal axis [W].
Regarding Claim 28:
Wu discloses an apparatus according to claim 27, wherein the tab (Fig. 7C-D elements 760c2) is substantially symmetric about the longitudinal axis (paragraphs 54-56).
Regarding Claim 29:
Wu discloses an apparatus according to claim 27, wherein the conductive electrode (Figs. 2-3 element 340b/220) has, along the longitudinal axis [L], a uniform shape within the first portion (Fig. 2 element 205), and a tapered shape within the second portion (element D1).
Regarding Claim 30:
Wu discloses an apparatus according to claim 27, wherein the conductive electrode (Fig. 2 element 220) includes polysilicon (paragraph 37).
Regarding Claim 31:
Wu discloses an apparatus according to claim 27, wherein the semiconductor substrate (Figs. 3 element 320) includes silicon carbide (paragraph 80).
Regarding Claim 32:
Wu discloses an apparatus according to claim 27, being a shield structure of a shielded gate metal oxide semiconductor field effect transistor (paragraphs 15, 25, and 59).
Regarding Claim 33:
Wu discloses an apparatus (Fig. 7A) comprising:
a first conductive electrode (element 720a) disposed in a first trench (paragraph 48), the first trench having a first portion (element 705a) in an active area [ACTIVE] and a second portion (element D1) in a termination region [TERMINATION], the first trench having a first longitudinal axis [L] extending from within the active area into the termination region (paragraphs 48-49), the first conductive electrode having, along the first longitudinal axis, a uniform shape within the first portion, and a tapered shape within the second portion (Fig. 2 element 220 and 3C-3C line), and
a second conductive electrode (element 730a) disposed in a second trench (paragraph 48), the second trench having a third portion in the active area (element 705a) and a fourth portion in the termination region (element 760a), the second trench having a second longitudinal axis [L] extending from within the active area into the termination region (paragraphs 48-49), the second conductive electrode having a uniform shape along the second longitudinal axis (Fig. 2 element 230 and 3A-3A line).
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.
Claims 23, 25, 34 are rejected under 35 U.S.C. 103 as being obvious over Wu et al. (US20190006512A1) in view of Burke et al. (US20140197483 A1).
The applied reference has a common assignee with the instant application. Based upon the earlier effectively filed date of the reference, it constitutes prior art under 35 U.S.C. 102(a)(2). Additionally, based upon the earlier publication date of the reference, it constitutes prior art under 35 U.S.C. 102(a)(1).
Regarding Claim 23:
Wu discloses an apparatus according to claim 21, but does not explicitly disclose where the terminus includes an extension and a reverse taper.
Burke, however, discloses an analogous trench shielding structure (Fig. 16), comprising a trench (Figs. 6-16 element 22), a dielectric lining (element 24) disposed in the trench, and a conductive electrode (element 21) disposed on the dielectric lining; wherein the shield structure (element 21) tapers to a terminus (Figs. 17-19) and the terminus includes at least one of an extension (elements 221/224) and a reverse taper (elements 222/226).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device described in Wu further in view of Burke to explicitly include where the terminus of the shield structure includes at least one of an extension and a reverse taper because both are directed to analogous shielding structures for MOSFET devices. Doing so improves the reliability and performance of these devices (Burke, paragraphs 5-7).
Regarding Claim 25:
Wu discloses an apparatus according to claim 21, but does not explicitly disclose an aspect ratio of the maximum width of the shield structure in the diffusion region and the minimum width at the terminus to be about 3:1.
Burke, however, discloses analogous trench shielding structures (Fig. 16), comprising a trench (Figs. 6-16 element 22), a dielectric lining (element 24) disposed in the trench, and a conductive electrode (element 21) disposed on the dielectric lining; wherein an aspect ratio characterizing a maximum width of the shield structure in the active region and a minimum width of the shield structure at the terminus is about 3:1 (paragraphs 50 and 61-63).
The examiner first notes that Burke does not explicitly disclose a specific aspect ratio for the maximum width of the shield structure in the active/diffusion region and minimum width at the terminus. The examiner next notes the widths of the shield structures is a result effective variable because adjusting the maximum and minimum width values can have a direct effect on the electrical performance of the MOSFET device. However, Burke recognizes that the variations in the widths of the shielded structures (Figs. 17-19 elements 170/180/190) impacts the long-term reliability of these structures (paragraphs 61-63). Furthermore, Burke recognizes that improving MOSFET devices depends on the performance of these shielded electrode structures (paragraphs 5-7).
Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to vary, through routine optimization, the widths of the shield structures for the intended aspect ratio as Burke has identified the widths as a result-effective variable. Further, one of ordinary skill in the art would have had a reasonable expectation of success to arrive at an aspect ratio of 3:1 for a maximum width in the diffusion/active region and a minimum width at the terminus, in order to achieve the desired improvements in breakdown voltage, as taught by Burke. MPEP 2144.05
Regarding Claim 34:
Wu discloses an apparatus according to claim 33, further comprising a second tab (Figs. 7C-D elements 760c2/760d2) intersecting an end of the fourth portion (elements 760c1/760d1), the second tab extending in a direction transverse to the second longitudinal axis [W]. However, Wu does not explicitly disclose a first tab intersecting an end of the second portion of the first conductive electrode.
Burke discloses an analogous trench shielding structure (Fig. 16-18), comprising a first trench (Figs. 6-16 element 22) and a conductive electrode (element 21) disposed in the trench, a first portion in an active area (element 172; paragraphs 61-63) and a second portion (elements 170/180/190) with a tapered shape in a termination region (elements 201/202); further comprising a first tab intersecting an end of the second portion (elements 183/193), the first tab extending in a direction transverse to the first longitudinal axis (paragraphs 62-63).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device described in Wu further in view of Burke to explicitly include a first tab intersecting the tapered end of the second portion – extending in a direction traverse to the first longitudinal axis – because both are directed to analogous shielding structures for MOSFET devices. Doing so improves the reliability and performance of these devices (Burke, paragraphs 5-7).
This rejection under 35 U.S.C. 103 might be overcome by: (1) a showing under 37 CFR 1.130(a) that the subject matter disclosed in the reference was obtained directly or indirectly from the inventor or a joint inventor of this application and is thus not prior art in accordance with 35 U.S.C.102(b)(2)(A); (2) a showing under 37 CFR 1.130(b) of a prior public disclosure under 35 U.S.C. 102(b)(2)(B); or (3) a statement pursuant to 35 U.S.C. 102(b)(2)(C) establishing that, not later than the effective filing date of the claimed invention, the subject matter disclosed and the claimed invention were either owned by the same person or subject to an obligation of assignment to the same person or subject to a joint research agreement. See generally MPEP § 717.02.
Claim 26 is rejected under 35 U.S.C. 103 as being unpatentable over Wu et al. (US20190006512A1) in view of Baburske et al. (US20170148893A1).
Regarding Claim 26:
Wu discloses an apparatus according to claim 1, but does not explicitly disclose where a first side of the conductive electrode is tapered and a second side is straight.
Baburske, however, discloses an analogous shielding trench structure (Fig. 5), comprising conductive electrode structures (elements 150/180, paragraph 71) wherein a first side of the conductive electrode (Fig 8E element 180a) is tapered, and a second side, opposite the first side, is straight (paragraphs 97-105).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device described in Wu further in view of Baburske to explicitly include a first tapered side of the conductive electrode and a second straight side – opposite to the first – because both are directed to analogous protective trench structures for transistor devices. Doing so improves the long-term stability and breakdown voltage that can occur in these types of transistor devices (Baburske, paragraphs 80-81).
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Weyers et al. (US 20150380542 A1).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Chloë E Benton whose telephone number is (571)272-9976. The examiner can normally be reached Monday-Thursday: 8am-6pm EST.
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/CALEEN O SULLIVAN/Primary Examiner, Art Unit 2899
/Chloë E Benton/Examiner, Art Unit 2899
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