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 .
DETAILED ACTION
Election/ Restrictions
Applicant's election of group II: claims 1-16, in the “Response to Election / Restriction Filed - 11/26/2025”, withdrawal of non-elected claim(s) 17-20 is/are acknowledged. This office action considers claims 1-20, in “Claims - 05/24/2023”, pending for prosecution, of which claim(s) 17-20 is/are withdrawn.
Priority
Acknowledgment is made of applicant's claim for foreign benefit based on JP2022-111146 filed on 07/11/2022.
Claim Rejections - 35 USC § 112
The following is a quotation of the second paragraph of 35 U.S.C. 112:
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 1-16 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 pre-AIA the applicant regards as the invention.
Claim 1 recites:
“an anode region of a second conductivity type provided to be closer to a front surface side of the semiconductor substrate than the drift region; and a trench contact portion provided at a front surface of the semiconductor substrate in the diode portion”. As seen in this claim recitation, “a front surface” has been recited twice which make the claim indefinite. It is unclear if they are the same or different. The applicant may recite the following to overcome this rejection:
“an anode region of a second conductivity type provided to be closer to a front surface side of the semiconductor substrate than the drift region; and a trench contact portion provided at the front surface of the semiconductor substrate in the diode portion”.
Claims 2-16 depend from claim 1.
Claim Rejections - 35 USC § 102
The following is a quotation of 35 U.S.C. 102(a)(1) that forms the basis for the rejection set forth in this Office action:
(a) NOVELTY; PRIOR ART.—A person shall be entitled to a patent unless—
(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;
Notes: when present, semicolon separated fields within the parenthesis (; ;) represent, for example, as (30A; Fig 2B; [0128]) = (element 30A; Figure No. 2B; Paragraph No. [0128]). For brevity, the texts “Element”, “Figure No.” and “Paragraph No.” shall be excluded, though; additional clarification notes may be added within each field. The number of fields may be fewer or more than three indicated above. These conventions are used throughout this document.
Claims 1-2, 5 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Tamura et al. (US 20210050345 A11 – hereinafter Tamura).
Regarding Claim 1, Tamura teaches a semiconductor device that includes a diode portion (see the entire document; Figs. 1A-2C; specifically, ([0077] - [0177]), and as cited below), comprising:
a drift region (18 – Fig. 2C) of a first conductivity type ([0080]) provided in a semiconductor substrate (10 – [0079]);
an anode region (82) of a second conductivity type ([0082]) provided to be closer to a front surface side (top surface) of the semiconductor substrate (10) than the drift region (18); and
a trench contact (54 – [0177])) portion provided at a front surface of the semiconductor substrate in the diode portion (10), wherein
in a depth direction of the semiconductor substrate, a doping concentration of the anode region at a same depth as that of a bottom portion of the trench contact portion is 1E16 cm-3 or more and 1E17 cm-3 or less ([0086] – “the doping concentration of the second anode region 82 is 1E16 cm.sup.−3 or higher and 1E17 cm.sup.−3 or lower”).
Regarding Claim 2, Tamura teaches the semiconductor device according to claim 1, wherein the anode region has a peak of the doping concentration in the depth direction of the semiconductor substrate (Fig. 1D show 82 having a peak), and the bottom portion of the trench contact portion is closer to the front surface side than the peak of the doping concentration of the anode region, in the depth direction of the semiconductor substrate (that is bottom of 54 is closer to from side of 10 in Fig. 2C).
Regarding Claim 5, Tamura teaches the semiconductor device according to claim 1, wherein the anode region has a thickness of 0.6 μm or more and 3.0 μm or less in the depth direction of the semiconductor substrate, and has a flat portion with a doping concentration of 1E16 cm-3 or more and 1E17 cm-3 or less ([0087]).
Allowable Subject Matter
Claims 3-4, 6-16 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 the Examiner’s Reasons for Allowance:
The prior art fails to disclose and would not have rendered obvious:
Regarding claim 3: The semiconductor device according to claim 2, wherein the anode region has a positive slope of the doping concentration at the same depth as that of the bottom portion of the trench contact portion in the depth direction of the semiconductor substrate.
Claim 4 depends from claim 3.
Regarding claim 6: The semiconductor device according to claim 5, wherein a depth of a lower end of the trench contact portion is 0.3 μm or more and 0.6 μm or less from the front surface of the semiconductor substrate.
Regarding claim 7: The semiconductor device according to claim 1, comprising a diode plug region of the second conductivity type which is selectively provided in an extension direction of a trench below the bottom portion of the trench contact portion and which has a doping concentration higher than that of the anode region.
Claim 8 depends from claim 7.
Regarding claim 9: The semiconductor device according to claim 1, further comprising: a transistor portion, wherein the transistor portion has an emitter region of the first conductivity type which is provided above the drift region and which has a doping concentration higher than that of the drift region, and a base region of the second conductivity type provided above the drift region, and the doping concentration of the anode region is lower than a doping concentration of the base region.
Claims 11-16 depend from claim 9.
Regarding claim 10: The semiconductor device according to claim 2, further comprising: a transistor portion, wherein the transistor portion has an emitter region of the first conductivity type which is provided above the drift region and which has a doping concentration higher than that of the drift region, and a base region of the second conductivity type provided above the drift region, and the doping concentration of the anode region is lower than a doping concentration of the base region.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MOHAMMAD A. RAHMAN whose telephone number is (571) 270-0168 and email is mohammad.rahman5@uspto.gov. The examiner can normally be reached on Mon-Fri 8:00-5:00 PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Julio J. Maldonado can be reached on (571) 272-1864. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/MOHAMMAD A RAHMAN/
Primary Examiner, Art Unit 2898