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 .
Claim Rejections - 35 USC § 102
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 18 – 19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Zeng et al, (US 2012/0043602).
(Claim 18) Zeng et al. teach a method for forming a trenched power device comprising:
forming a drift region (fig. 19 #N1) of a first conductivity type overlying a semiconductor substrate;
etching trenches into the drift region, the trenches including a first trench portion (fig. 20, shallow trench) and a second trench portion (deep trench), the second trench portion being deeper than the first trench portion;
masking the trenches to provide mask openings over portions of the trenches (fig. 20);
implanting dopants of a second conductivity type through bottom surfaces of the second trench portions to form shield regions of the second conductivity type below areas of the second trench portions (fig. 20);
insulating sidewalls of the trenches (fig. 21);
at least partially filling the trenches with a conductive material to form trench gates (fig. 22);
forming a well region (fig. 27a #P above #N2) of the second conductivity type (P) overlying the drift region (#N1/N2);
forming a source region (fig. 27a, #N++) of the first conductivity type (N) overlying the well region (#P above #N2);
forming a source electrode (fig. 27a, top metal, analogous to fig. 5a labeled # Source Metal) electrically contacting the source region and the well region,
wherein the shield regions (fig. 27a #P below N2 and #P on sidewalls of #N2) are electrically connected (P+) to the source electrode via the well region (fig. 27a #P above #N2; and
the trench gates having first vertical sidewalls along the well region and along a portion of the drift region (#N2),
wherein applying a gate voltage to the trench gates greater than a threshold voltage inverts the well region along the sidewalls to create a conductive channel between the source region and the drift region (Claim 3).
(Claim 19) Zeng et al. teach wherein the trench gates are substantially linear, are parallel to each other, and are electrically connected together (fig. 27a).
Allowable Subject Matter
Claims 1 – 17 are allowable, because prior art does not render obvious:
(Claim 1) a shield region of the second conductivity type below the second trench portion and along a portion of the second vertical sidewalls, such that the second vertical walls do not abut the drift region so that no conductive channel is created between the source region and the drift region when the gate voltage is greater than the threshold voltage,
wherein the shield region is electrically connected to the source electrode via the well region.
Conclusion
Prior art made of record and not relied upon, considered pertinent to applicant's disclosure are listed in PTO – 892 Form.
Contact Information
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/IGWE U ANYA/Primary Examiner, Art Unit 2891
June 23, 2026
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