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 .
Status of the Claims
Amendment filed December 23, 2025 is acknowledged. Claim 1 has been amended. Claims 1-10 are pending.
Action on merits of claims 1-10 follows.
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 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over SAITO et al. (US. Pub. No. 2007/0138543) of record, in view of TAMAKI et al. (US. Pub. No. 2019/0088737).
With respect to claim 1, SAITO ‘543 teaches a semiconductor device substantially as claimed including:
a first semiconductor layer (2) having an N-type of conductivity; and
a second semiconductor layer (12) that is formed on the first semiconductor layer (2), and including an active region, a frame region, and a termination region,
wherein the active region comprises a plurality of first P-pillars (34) and first N-pillars (33) formed between the plurality of first P-pillars (34),
the frame region comprises an upper frame region (5) formed to extend in a first direction while having a P-type of conductivity, and a lower frame region that is formed below the upper frame region (5) and including a plurality of second P-pillars (34) and second N-pillars (33) formed between the plurality of second P-pillars (34), and
the termination region comprises an upper termination region (17) that extends in the first direction while having the P-type of conductivity, a middle termination region having the N-type of conductivity and formed below the upper termination region (17), and a lower termination region formed below the middle termination region and including a plurality of third P-pillars (34) and third N-pillars (34) formed between the plurality of third P-pillars (34),
wherein the upper termination region (17) comprises an area disposed within the upper termination region,
wherein the area is disposed in the upper termination region (17) above the middle termination region and the lower termination region. (See FIG. 20).
Thus, SAITO is shown to teach all the features of the claim with the exception of explicitly disclosing the upper termination region comprises a plurality of segmentation area.
However, TAMAKI teaches a semiconductor device including:
a termination region comprises an upper termination region (38) that extends in first direction while having a P-type of conductivity, a middle termination region (14) having N-type of conductivity and formed below the upper termination region (38),
wherein the upper termination region (38) comprises a plurality of segmentation areas disposed within the upper termination region (38), the plurality of segmentation areas having a first segmentation area (38a), at least one intermediate segmentation are (38b), and a last segmentation area (38c) along the first direction,
wherein the plurality of segmentation areas (38a-c) are disposed in the upper termination region (38) above the middle termination region, and
wherein an impurity concentration of the first segmentation area (38a) is the highest, an impurity concentration of each of the at least one intermediate segmentation area (38b) is lower than that of the first segmentation area (38a), and an impurity concentration of the last segmentation area (38c) is the lowest. (See FIG. 4A).
Therefore, it would have been obvious to one having ordinary skill in the art at the time of invention was made to form the upper termination region of SAITO comprising the plurality of segmentation area as taught by TAMAKI to prevent a variation in breakdown voltage caused by charge imbalance.
With respect to claim 2, the entire lower termination region of SAITO is covered by the upper termination region (17).
With respect to claim 3, the middle termination region and the upper termination region (17) of SAITO are sequentially formed on the third P-pillar (34).
With respect to claim 4, the second P-pillar (34) of SAITO is connected to the top surface of the second semiconductor layer (12) through the upper frame region (5).
With respect to claim 5, the third P-pillar (34) of SAITO is distanced from the top surface of the second semiconductor layer (12).
With respect to claim 6, the top surface of the middle termination region of SAITO is distanced from the top surface of the second semiconductor layer (12).
With respect to claim 7, the middle termination region of SAITO is connected with at least one of the plurality of third N-pillars (33) of the lower termination region.
With respect to claim 8, the upper termination region (17) of SAITO is connected with the upper frame region (5).
With respect to claim 9, the upper frame region (5) of SAITO is connected with at least one of the plurality of second P-pillars (34) of the lower frame region.
With respect to claim 10, impurity concentration of the upper frame region (5) of SAITO is higher than that of the upper termination region (17).
Response to Arguments
Applicant's arguments filed December 23, 2025 have been fully considered but they are not persuasive.
Regarding claim 1, Applicant argues:
SAITO discloses that "A source electrode 7 serving as a first main electrode is provided on part of the source region 6 and on the portion between the base region 5 and the source region 6. The source region 6 is electrically connected to the source electrode 7" (paragraph 0041) and "[a] control electrode (gate electrode) 9 is provided on the insulating film (gate insulating film) 8" (paragraph 0043). Because the source regions 6 are provided in the base regions 5, a region including the base regions 5 should be interpreted into an active region. Thus, SAITO may at most teach an active region of Claim 1, but does not teach a frame region as recited in claim 1.
However, As clearly shown in FIG. 20, “5” is clearly the “upper frame region” because it “extend in a first direction while having a P-type conductivity” as recited in claim 1.
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Applicant also argues: “… but does not teach a middle termination region having the N-type of conductivity and formed below the upper termination region and above the lower termination region”.
Again, as shown in FIG. 20, the “middle termination region” is clearly formed below the upper termination region 17 and above the lower termination region (P-N pillars), and having the N-type conductivity.
In response to applicant's argument based upon the age of the references, i.e., significantly earlier reference or later-developed, contentions that the reference patents are old are not impressive absent a showing that the art tried and failed to solve the same problem notwithstanding its presumed knowledge of the references. See In re Wright, 569 F.2d 1124, 193 USPQ 332 (CCPA 1977).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ANH D MAI/Primary Examiner, Art Unit 2893