Ex Parte VeerammaDownload PDFPatent Trial and Appeal BoardDec 15, 201713892237 (P.T.A.B. Dec. 15, 2017) Copy Citation United States Patent and Trademark Office UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O.Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. IXYS-01328 7775 EXAMINER YECHURI, S IT ARAM AR AO S ART UNIT PAPER NUMBER 2818 MAIL DATE DELIVERY MODE 13/892,237 05/10/2013 Subhas Chandra Bose Jayappa Veeramma 47713 7590 12/15/2017 IMPERIUM PATENT WORKS P.O. BOX 607 Pleasanton, CA 94566 12/15/2017 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte SUBHAS CHANDRA BOSE JAYAPPA VEERAMMA1 Appeal 2017-001762 Application 13/892, Til2 Technology Center 2800 Before JEFFREY T. SMITH, MARKNAGUMO, and MERRELL C. CASHION, JR., Administrative Patent Judges. SMITH, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE This is an appeal under 35 U.S.C. § 134 from the final rejection of claims 1 and 3—19.3 We have jurisdiction under 35 U.S.C. § 6. We reverse. Appellant’s invention relates generally to a packaged overvoltage protection circuit comprising a Break Over Diode device (BOD). The BOD 1 This is the named inventor of the present application. 2 According to Appellant, the real party in interest is IXYS Corporation. See App. Br. 1. 3 The Examiner has indicated the subject matter of claims 20—23 is allowable. (Final Act. 2). Appeal 2017-001762 Application 13/892,237 device undergoes breakover and turns on if an excessive forward voltage develops across a power thyristor, coupled in parallel with the BOD. (Spec. 110). Independent claims 1, 9, and 12 are representative of the appealed subject matter. Representative claims 1 and 12 are reproduced below: 1. A packaged overvoltage protection circuit comprising: a first semiconductor die, wherein the first semiconductor die comprises a breakover diode having a reverse breakdown voltage of at least four hundred volts; a second semiconductor die, wherein the second semiconductor die comprises a breakover diode having a reverse breakdown voltage of at least four hundred volts; a package housing that encloses the first and second semiconductor dice; a first package terminal; and a second package terminal, wherein the first and second semiconductor dice are coupled such that if a positive voltage of adequate magnitude is present between the second package terminal and the first package terminal then breakover of the breakover diodes in the first and second semiconductor dice occurs and a current flows in a current path from the second package terminal, through the breakover diode of the first semiconductor die, through the breakover diode of the second semiconductor die, and to the first package terminal, and such that if a negative voltage of nine hundred volts or less is present between the second package terminal and the first package terminal then neither of the breakover diodes of the first and second semiconductor dice suffers reverse breakdown, and wherein the packaged overvoltage protection circuit has no package terminal other than the first and second package terminals. 2 Appeal 2017-001762 Application 13/892,237 12. An apparatus comprising: a first package terminal; a second package terminal, wherein the apparatus has no more than two package terminals; and means for blocking substantially all current flow from the second package terminal to the first package terminal for positive voltages less than a first voltage between the second and first package terminals, for initiating conduction of a breakover current from the second package terminal to the first package terminal if a positive voltage equal to the first voltage becomes present between the second and first package terminals, and for blocking substantially all current flow from the first package terminal to the second package terminal for negative voltages less than a second voltage between the second package terminal and the first package terminal, wherein the absolute magnitude of the second voltage exceeds the first voltage, wherein the first voltage is at least nine hundred volts, wherein the means comprises no semiconductor die other than a plurality of semiconductor dice, and wherein each die of the plurality of semiconductor dice comprises a breakover diode. Claims Appendix to App. Br. Appellant (see generally App. Br.) requests review of the following rejections: I. Claims 1, 3—5, and 8 rejected under 35 U.S.C. § 103(a) as unpatentable over Vogel (US 5,710,463 A, iss. Jan. 20, 1998) in view of Shombert (US 3,231,796 A, iss. Jan. 25, 1966). (Final Act. 3 — 5). II. Claim 6 and 7 rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Vogel, Shombert, and 3 Appeal 2017-001762 Application 13/892,237 Thiele (US 4,651,251, iss. Mar. 17, 1987). (Final Act. 5 - 6). III. Claims 9—11 rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Vogel, Shombert, and Thiele. (Final Act. 6 — 9). IV. Claims 12 and 13 rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Vogel and Shombert. (Final Act. 9—11). V. Claims 14—18 rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Vogel, Shombert, and Thiele.4 (Final Act. 11-12). VI. Claim 19 rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Vogel, Shombert, and Thiele as combined and further in view of Faust et al. (US 4,367,418 A, iss. Jan. 4, 1983). (Final Act. 12—13). The complete statement of the rejections on appeal appears in the Final Office Action. (Final Act. 3—13). OPINION5 After consideration of the evidence in this appeal record in light of the respective positions advanced by the Examiner and Appellant, we determine the Examiner erred in the determination that the combination of Vogel and 4 The Examiner has included a discussion of claims 16—18 in the body of the rejection. However, the Examiner has inadvertently excluded claims 16—18 from the statement of the rejection. 5 Our discussion applies to independent claims 1, 9, and 12. 4 Appeal 2017-001762 Application 13/892,237 Shombert teaches (i) a packaged overvoltage protection circuit with breakover diodes having a reverse breakdown voltage of at least four hundred volts as required by independent claims 1 and 9, and (ii) a two- terminal apparatus with breakover diodes that block current flow between the terminals for negative voltages greater than nine hundred volts in magnitude as required by independent claim 12. Accordingly, we reverse Rejections I—VI.6 7 Independent Claims 1, 9 and 12.1 Appellant argues neither Vogel nor Shombert teaches a breakover diode having a reverse breakdown voltage that exceeds 400 V as required by independent claim 1. (App. Br. 9-10). Appellant argues Vogel fails to disclose a PNPN structure having a reverse breakdown voltage that exceeds four hundred volts. Appellant argues the Examiner is relying on hindsight to modify the breakover diode of Vogel in accordance with the teachings of Shombert so that the breakover diode of Vogel would have a reverse breakdown voltage. (App. Br. 10). Thus, Appellant argues the combination of Vogel and Shombert would not have resulted in the claimed invention. (App. Br. 13). Appellant further argues Shombert does not teach how to modify a breakover diode to achieve a reverse breakdown voltage and the Examiner fails to explain how the teachings of Shombert are utilized to modify the breakover diode of Vogel. (App. Br. 13—14). 6 The additional references relied upon by the Examiner in the obviousness rejections were cited to address limitations of the dependent claims that are not related to our discussion of the independent claims. 7 Appellant relies on substantially the same arguments when addressing the limitations of independent claims 1 and 9. (App. Br. 9-14, 16—18). We will limit our discussion to claim 1. 5 Appeal 2017-001762 Application 13/892,237 Addressing independent claim 12, Appellant argues neither Vogel nor Shombert teaches breakover diodes that block current flow for negative voltages greater than nine hundred volts. (App. Br. 19). Appellant argues Shombert fails to disclose a two terminal apparatus with breakover diodes that block current flow for negative voltage between terminals. (App. Br. 19). Thus, Appellant argues the Examiner’s rejection is premised on hindsight because no rationale has been provided to modify Vogel’s breakover diodes to impart a reverse breakdown voltage. (App. Br. 20). The Examiner found Vogel teaches a packaged overvoltage protection circuit as required by the claimed invention. (Final Act. 3^4 (citing Fig. 3, col. 3)). The Examiner found Vogel does not teach: “having a reverse breakdown voltage of at least four hundred volts†nor “such that if a negative voltage of nine hundred volts or less is present between the second package terminal and the first package terminal then neither of the breakover diodes of the first and second semiconductor dice suffers reverse breakdown.†(Final Act. 4). The Examiner found Shombert teaches how to adjust the forward breakover and reverse breakdown voltages. The Examiner specifically states: Shombert [teaches] “Pnpn semiconductor switch with predetermined forward breakover and reverse breakdown voltages†where he teaches how to adjust the forward breakover and reverse breakdown voltages. See column 2, 3 and 4[,] see Fig. 1 . . . reverse breakdown. (Final Act. 4). The Examiner concluded it would be obvious to modify the Pnpn of Vogel to meet the claimed invention. The Examiner specifically states: 6 Appeal 2017-001762 Application 13/892,237 it would be obvious to modify the Pnpn of Vogel to have reverse breakdown voltage of for example 500 volts such that “having a reverse breakdown voltage of at least four hundred volts†and “such that if a negative voltage of nine hundred volts or less is present between the second package terminal and the first package terminal then neither of the breakover diodes of the first and second semiconductor dice suffers reverse breakdown.†(Final Act. 5). The Examiner cites Godse8 and McKay9 to explain electric breakdown is inherent to semiconductor junctions and Vogel’s structure. (Ans. 3—8). The Examiner points to Fig. 3 of McKay and states that the breakdown voltage is “approaching 400 V and note that that is all that was tested†(Ans. 5). The Examiner further states: a person of ordinary skill in the art understands that the PNPN of Vogel Fig. 3 relies upon reverse biased PN junctions to block current from flowing in both directions, but the phenomenon of Avalanche breakdown will also occur in both directions, thus the Examiner states for the record that inherently the PNPN of Vogel Fig. 3 has a reverse breakdown voltage and when that voltage is exceeded current will flow in the direction from Cathode K to Anode A and this is due to Avalanche breakdown of the reverse biased junctions. (Ans. 7—8). In response to the Examiner’s newly presented inherency argument, Appellant argues McKay clearly fails to show a reverse breakdown voltage of at least 400V and FIG. 3 of McKay shows the breakdown voltage is well 8 Atul P. Godse & Deepali A. Godse, Electronics and Microprocessors, 58— 64 (2008). 9 K. G. McKay, Avalanche Breakdown in Silicon, 94/4 Physical Review 877-84 (1954). 7 Appeal 2017-001762 Application 13/892,237 below 400V. (Reply Br. 5). Appellant further argues nowhere does the cited art teach the claimed breakover diode having a reverse breakdown voltage of at least 400V. (Reply Br. 5). We agree with Appellant that the Examiner’s rejections of the independent claims 1, 9, and 12 are not well-founded. An inherent characteristic must be inevitable, and not merely a possibility or probability. See In re Oelrich, 666 F.2d 578, 581 (CCPA 1981). The Examiner has not pointed to a specific embodiment in Vogel that teaches the disputed subject matter. Nor has the Examiner provided an explanation as to how the teachings of Shombert would have been combined with the teachings of Vogel to necessarily result in (i) a packaged overvoltage protection circuit with breakover diodes having a reverse breakdown voltage of at least four hundred volts as required by independent claims 1 and 9, and (ii) a two- terminal apparatus with breakover diodes that block current flow between the terminals for negative voltages greater than nine hundred volts in magnitude as required by independent claim 12. The Examiner’s reliance on Godse and McKay does not establish that the structure of Vogel alone or in combination with the teachings of Shombert inherently encompasses a reverse breakdown voltage of at least four hundred volts or a two-terminal apparatus with breakover diodes that block current flow between the terminals for negative voltages greater than nine hundred volts in magnitude as required by the claimed invention. Accordingly, we reverse the Examiner’s decision to reject claims 1 and 3—19 for the reasons presented by Appellant and given above. 8 Appeal 2017-001762 Application 13/892,237 ORDER The obviousness rejections of claims 1 and 3—19 are reversed. REVERSED 9 Copy with citationCopy as parenthetical citation