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 .
Election/Restrictions
Applicant’s election of Invention I in the reply filed on 18 March 2026 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)).
Claims 11-14 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.
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.
Claim(s) 1, 2 and 5-7 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Poelzl (US 2010/0055892 A1).
Regarding claim 1, Poelzl discloses a method for forming a semiconductor structure (Fig 2a-2D; ¶23-¶38), comprising: providing a substrate having a front surface and a rear surface; forming a plurality of trenches (30) extending into the substrate from the front surface of the substrate; forming a polishing stop structure (39) at a bottom of each of the plurality of trenches; filling the plurality of trenches with a gap-filling material layer (34); and subjecting the rear surface of the substrate to a polishing process to remove a portion of the substrate from the rear surface until the polishing stop structure is exposed (¶37).
Regarding claim 2, Poelzl discloses that the polishing stop structure has a U shaped sectional profile (Figs).
Regarding claim 5, Poelzl discloses that the polishing process comprises a chemical mechanical polishing process (¶37, CMP).
Regarding claim 6, Poelzl discloses that, before subjecting the rear surface of the substrate to the polishing process, the method further comprises: forming circuit elements in active areas on the front surface of the substrate; and forming a first interconnect structure on the front surface of the substrate (¶37, the transistor formed already is the circuit element while the usual contacts of ¶37 are the interconnect structures).
Regarding claim 7, while the field electrode 34 of Poelzl is embedded within the gate trench which divides the active areas, such that while the field electrode is not in itself isolating it forms part of an isolated structure and as such the active areas are electrically isolated from one another by the gap-filling material layer.
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.
Claim(s) 3 and 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Poelzl.
Regarding claim 3, the polishing stop structure of Poelzl comprises a silicon oxide layer (¶24) instead of the silicon nitride layer as claimed. However, it would have been obvious to one of ordinary skill in the art to form the polishing stop structure from silicon nitride, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960).
Regarding claim 4, the polishing stop structure of Poelzl comprises a silicon oxide layer (¶24) instead of the carbon doped silicon nitride layer as claimed. However, it would have been obvious to one of ordinary skill in the art to form the polishing stop structure from carbon doped silicon nitride, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960)
Allowable Subject Matter
Claims 8-10 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.
The following is a statement of reasons for the indication of allowable subject matter:
Neither Poelzl nor other prior art suggest the method of claim 6 where U-shaped recesses are formed on the rear surface of the substrate by removing the polishing stop structure. The polishing stop structure of Poelzl serves to isolate the field electrode and would not be removed.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL P SHOOK whose telephone number is (571)270-7890. The examiner can normally be reached 9:00 am - 5:00 pm, Mon-Fri.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, WILLIAM KRAIG can be reached at (571)272-8660. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DANIEL P SHOOK/Primary Examiner, Art Unit 2896
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