DETAILED ACTION
Response to Arguments
Applicant's arguments filed 6/23/2026 have been fully considered but they are not persuasive.
Regarding claim 1, applicant argues on page 12 that Werber (US 2015/0014743) does not disclose “the first trench contact is formed deeper than a bottom of a contact region, and deeper than an upper surface side of the base region” because Werber’s trench contact 302 reaches a depth equal to the p-type node zone 116 – but does not go deeper than the upper-side surface of the p type anode zone 116. However, fig. 4A of Werber discloses that the anode zone 116 extends from the first surface 101 to drift zone 121 so the bottom of trench contact 302 is lower than the top of anode zone 116 (first surface 101). Fig. 4A of Werber discloses that the first trench contact (302 in 410b) is formed deeper (bottom of 302 below bottom of 110) than a bottom of a contact region (bottom of 110), and deeper (bottom of 302 below bottom of 101) than an upper surface side 101 of the base region 116. Thus claim 1 remains rejected.
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 1-4, 6-8, 11-14, and 19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Werber et al. (US 2015/0014743) (“Werber”).
With regard to claim 1, fig. 4A of Werber discloses a method for manufacturing a semiconductor apparatus including: a transistor 410a portion provided in a semiconductor substrate 100 of a first conductivity type (n) and including a base region 115 of a second conductivity type (p); a diode portion 410b provided in the semiconductor substrate 100 and including an anode region 116 of the second conductivity type (p); and a first trench contact (302 in 410b) provided in the diode portion 410b on a front surface side 101 of the semiconductor substrate 100, the method comprising: acquiring a condition of trade-off between a reverse recovery loss (“reverse recovery losses”, par p0046]) of the diode portion 410b and a forward voltage (“forward voltage”, par [0042]) of the diode portion 410b; deciding a target characteristic required for the semiconductor apparatus 600; determining whether a first depth 332 of the first trench contact 332 according to the target characteristic (“reduce switching losses”, par [0001]) satisfies a diode condition which is a condition (“reduce switching losses”, par [0001]) for realizing the target characteristic (“reduce switching losses”, par [0001]), of the condition of trade-off; and manufacturing the semiconductor apparatus 600 in which a depth 332 of the first trench contact (302 in 410b) is the first depth 332, wherein the first trench contact (302 in 410b) is formed deeper than a bottom of a contact region (bottom of 110), and deeper (bottom of 302 in 410b is below 101) than an upper surface side 101 of the base region 116.
With regard to claim 2, fig. 4A of Werber discloses that the determining whether the first depth 332 satisfies the diode condition (“reduce switching losses”, par [0001]) includes: acquiring the diode condition for a case where a doping concentration (“impurity concentration”, par [0056]) of the anode region 116 is a first doping concentration (“impurity concentration”, par [0056]); and determining whether the first depth 332 satisfies the diode condition at the first doping concentration (“impurity concentration”, par [0056]).
With regard to claim 3, fig. 4A of Werber discloses that the first doping concentration (“impurity concentration”, par [0056]) is a doping concentration (“impurity concentration”, par [0048]) of the base region 115.
With regard to claim 4, fig. 4A of Werber discloses that if the first depth 332 satisfies the diode condition (“reduce switching losses”, par [0001]) at the first doping concentration (“impurity concentration”, par [0056]), the manufacturing the semiconductor apparatus 600 includes manufacturing the semiconductor apparatus 600 in which the depth 332 of the first trench contact is the first depth 332, and if the first depth 332 does not satisfy the diode condition at the first doping concentration (“impurity concentration”, par [0056]), the determining whether the first depth 332 satisfies the diode condition (“reduce switching losses”, par [0001]) includes: acquiring the diode condition (“reduce switching losses”, par [0001]) for a case where the doping concentration (“decreasing impurity concentration”, par [0056]) of the anode region 116 is a second doping concentration lower (“decreasing impurity concentration”, par [0056]) than the first doping concentration (“impurity concentration”, par [0056]); and determining whether the first depth 332 satisfies the diode condition (“reduce switching losses”, par [0001]) at the second doping concentration (“decreasing impurity concentration”, par [0056]).
With regard to claim 6, fig. 4A of Werber discloses that the semiconductor apparatus 600 includes a second trench contact (302 in 410a) provided in the transistor portion 410a on the front surface side 101 of the semiconductor substrate 100, the method comprising: acquiring a threshold condition indicating a relationship between a depth (“ trench contacts 302 reach the body zones 115 at a distance to the first surface 101”, par [0062]) of the second trench contact (302 in 410a) and a threshold voltage of the transistor portion 410a; and determining whether a second depth (“ trench contacts 302 reach the body zones 115 at a distance to the first surface 101”, par [0062]) of the second trench contact (302 in 410a) according to the target characteristic satisfies a transistor condition which is a condition for realizing the target characteristic, of the threshold condition, and the manufacturing the semiconductor apparatus 600 includes manufacturing the semiconductor apparatus 600 in which the depth of the second trench contact (302 in 410a) is the second depth (“ trench contacts 302 reach the body zones 115 at a distance to the first surface 101”, par [0062]).
With regard to claim 7, fig. 4A of Werber discloses that the determining whether the first depth 332 satisfies the diode condition includes: acquiring the diode condition for a case where a doping concentration of the anode region 116 is a doping concentration of the base region 115; and determining whether the first depth 332 satisfies the diode condition at the doping concentration of the base region 115.
With regard to claim 8, fig. 4A of Werber discloses that the determining whether the second depth (“trench contacts 302 reach the body zones 115 at a distance to the first surface 101”, par [0062]) satisfies the transistor condition includes determining whether the second depth (“ trench contacts 302 reach the body zones 115 at a distance to the first surface 101”, par [0062]), which is a same as the first depth 332, satisfies the transistor condition.
With regard to claim 11, fig. 4A of Werber discloses that the diode condition includes a condition according to the depth 332 of the first trench contact (302 in 410b) within a predetermined range 332, the determining whether the first depth 332 satisfies the diode condition includes determining whether the first depth 332 is included in the predetermined range 332.
With regard to claim 12, fig. 4A of Werber discloses that the diode condition includes a condition according to the depth 332 of the first trench contact (302 in 410b) within a predetermined range 332, the determining whether the first depth 332 satisfies the diode condition includes determining whether the first depth 332 is included in the predetermined range 332.
With regard to claim 13, fig. 4A of Werber discloses that the diode condition includes a condition according to the depth 332 of the first trench contact (302 in 410b) within a predetermined range 332, the determining whether the first depth 332 satisfies the diode condition includes determining whether the first depth 332 is included in the predetermined range 332.
With regard to claim 14, fig. 4A of Werber discloses that the diode condition includes a condition according to the depth 332 of the first trench contact (302 in 410b) within a predetermined range 332, the determining whether the first depth 332 satisfies the diode condition includes determining whether the first depth 332 is included in the predetermined range 332.
With regard to claim 19, fig. 4A of Werber discloses that the semiconductor apparatus 600 includes an emitter region 110 of the first conductivity type (n) provided above the base region 115, and the second depth (“ trench contacts 302 reach the body zones 115 at a distance to the first surface 101”, par [0062]) is deeper than a depth from the front surface 101 of the semiconductor substrate 100 to a lower end (bottom of 110) of the emitter region 110.
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 15-16 are rejected under 35 U.S.C. 103 as being unpatentable over Werber et al. (US 2015/0014743) (“Werber”) in view of Guan et al. (US 2017/0110404) (“Guan”).
With regard to claim 15, Werber does not disclose that the first depth is 0 μm or more and 1.0 μm or less.
However, fig. 1C of Guan discloses the first depth is 0 μm or more (“0.3 um”, par [0034]) and 1.0 μm or less.
Therefore, it would have been obvious to one of ordinary skill in the art to form the contact trench of Werber with the depth of Guan in order to provide a suitable depth that will not cause a negative effect on breakdown voltage of the diode. See par [0034] of Guan.
With regard to claim 16, Werber does not disclose that the first depth is 0.3 μm or more and 0.4 μm or less.
However, fig. 1C of Guan discloses that the first depth is 0.3 μm (“0.3 um”, par [0034]) or more and 0.4 μm or less.
Therefore, it would have been obvious to one of ordinary skill in the art to form the contact trench of Werber with the depth of Guan in order to provide a suitable depth that will not cause a negative effect on breakdown voltage of the diode. See par [0034] of Guan.
Claims 18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Werber et al. (US 2015/0014743) (“Werber”) in view of Sandow et al. (US 2021/0296474) (“Sandow”).
With regard to claim 18, Werber does not disclose the semiconductor apparatus includes a plug contact region of the second conductivity type provided below the first trench contact and having a higher doping concentration than the base region.
However, fig. 2A of Sandow discloses that the semiconductor apparatus includes a plug contact region 148 of the second conductivity type (“highly doped region 148 of the second conductivity type”, par [0028]) provided below the first trench contact 146 and having a higher doping concentration (“highly doped region 148”, par [0024]) than the base region 122.
Therefore, it would have been obvious to one of ordinary skill in the art to form the trench contact of Werber with the high doped region underneath as taught in Sandow in order to provide for good ohmic contact with the metallization. See par [0030] of Sandow.
With regard to claim 20, the semiconductor apparatus includes a plug contact region of the second conductivity type provided below the first trench contact and the second trench contact and having a higher doping concentration than the base region.
However, figs. 2A-2B of Sandow discloses that the semiconductor apparatus includes a plug contact region 148 of the second conductivity type (“highly doped region 148 of the second conductivity type”, par [0028]) provided below the first trench contact 146 and the second trench contact 144 and having a higher doping concentration (“highly doped region 148”, par [0024]) than the base region 122.
Therefore, it would have been obvious to one of ordinary skill in the art to form the trench contact of Werber with the high doped region underneath as taught in Sandow in order to provide for good ohmic contact with the metallization. See par [0030] of Sandow.
Allowable Subject Matter
Claims 5, 9-10 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.
Regarding claim 5, Werber (US 2015/0014743) does not disclose if the first depth does not satisfy the diode condition at the second doping concentration, the determining whether the first depth satisfies the diode condition includes: acquiring the diode condition for a case where the doping concentration of the anode region is a third doping concentration lower than the second doping concentration; and determining whether the first depth satisfies the diode condition at the third doping concentration.
Regarding claim 9, Werber (US 2015/0014743) does not disclose the determining whether the first depth satisfies the diode condition includes: acquiring the diode condition for a case where a doping concentration of the anode region is a first doping concentration different from a doping concentration of the base region; and determining whether the first depth satisfies the diode condition at the first doping concentration. Claim 10 depends on claim 9 and is objected.
Claim 17 is allowed.
Regarding claim 17, Werber (US 2015/0014743) does not disclose a doping concentration of the anode region is 1e12/cm² or higher and 1e14/cm² or lower.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BENJAMIN T LIU whose telephone number is (571)272-6009. The examiner can normally be reached Monday-Friday 11:00am-7:30pm.
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/BENJAMIN TZU-HUNG LIU/Primary Examiner, Art Unit 2893
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