DETAILED ACTION
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) 1 thru 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Takahashi US 2019/0287926 A1. Takahashi discloses (see, for example, FIG. 1) a method of forming a warpage control structure 10 for a metal base plate 13, the method comprising: forming the metal base plate 13; forming a dissimilar metal layer (see, for example, paragraph [0039] that states nickel may be plated on the front surface of the metal base plate 13) on a surface of the metal base plate 13; and joining an insulation substrate 12 to a surface of the dissimilar metal layer with a joining material 17b being provided between the insulation substrate 12 and the surface of the dissimilar metal layer, the insulation substrate 12 including a ceramic substrate 12a, an upper metal plate 12b disposed on an upper surface of the ceramic substrate 12a, and a lower metal plate 12c disposed on a lower surface of the ceramic substrate 12a, such that the upper metal plate 12b and the lower metal plate 12c are disposed on both surfaces of the ceramic substrate 12a, the insulation substrate 12 being joined to the joining material 17b, the dissimilar metal layer, and the metal base plate 13 in a high temperature state such that the metal base plate 13 becomes substantially flat at a room temperature state, the high temperature state being between 250 – 300°C and the room temperature state being around 25°C, wherein α1 > α3 > α2 is satisfied, where α1 represents a linear expansion coefficient of the metal base plate 13, α2 represents a linear expansion coefficient of the dissimilar metal layer, and α3 represents a linear expansion coefficient of the upper metal plate 12b and the lower metal plate 12c, and the warpage control structure is configured to substantially cancel out warpage in the metal base plate caused by temperature changes. In paragraph [0039], Takahashi discloses the metal base plate 13 may be aluminum, which is the same material as the one used by the applicant as stated in paragraph [0019] of the specification. Further, in paragraph [0039], Takahashi discloses nickel (i.e. dissimilar metal layer) may be plated on the front surface of the metal base plate 13. In paragraph [0036], Takahashi discloses the lower metal plate 12c may be copper. In paragraph [0032], Takahashi discloses the ceramic substrate 12a may be ceramics. In paragraph [0033], Takahashi discloses the upper metal plate 12b may be copper, etc. Even though Takahashi discloses the base metal plate being aluminum, the upper and lower metal plate being copper, and the dissimilar metal layer being nickel, Takahashi does not specifically disclose the expression α1>α3>α2; however, it would have been obvious to one of ordinary skill in the art, at a time prior to the effective filing date, to have these layers and the expression α1>α3>α2 in order to prevent corrosion and have a material of high electrical conductivity to make connections to other structures. Regarding the limitation “the warpage control structure is configured to substantially cancel out warpage in the metal base plate caused by temperature changes”, this limitation is an inherent property given that cited prior art discloses the same structural limitations as recited by the applicant. Since the cited prior art discloses the same claimed structural limitations, it follows that it has the same properties. Where the claimed the prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F. 2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977).
Regarding claim 2, see, for example, paragraph [0039] wherein Takahashi discloses the metal base plate 13 may be aluminum, and the dissimilar metal layer being nickel. In paragraph [0033], and [0036], Takahashi discloses the upper metal plate 12b and lower metal plate 12c respectively may be copper.
Regarding claim 3, see, for example, paragraph [0039] wherein Takahashi discloses the joining material 17b may be solder.
Regarding claim 4, see, for example, FIG. 1 wherein Takahashi discloses a semiconductor element 11.
Regarding claim 5, see, for example, paragraph [0003] wherein Takahashi discloses semiconductor elements being used in an inverter device.
Regarding claim 6, see, for example, paragraph [0033] wherein Takahashi discloses the upper metal plate 12b having a thickness preferably 0.1. mm to 1.0 mm thick, and in paragraph [0036], Takahashi discloses the lower metal plate 12c having a thickness preferably 0.1 mm to 1.0 mm thick. Takahashi does not specifically disclose the metal base plate having a thickness between 3.5-4.0 mm and the dissimilar metal layer having a thickness of about 0.5 mm; however, it would have been obvious to one of ordinary skill in the art, at a time prior to the effective filing date, to have these thicknesses in order to support the warpage control structure with adequate heat radiation and corrosion resistance, and since it has been held that discovering an optimum value of a result effective value involves only routine skill in the art. In re Boesch, 617 F. 2d 272, 205 USPQ 215 (CCPA 1980).
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Any inquiry concerning this communication or earlier communications from the examiner should be directed to EUGENE LEE whose telephone number is (571)272-1733. The examiner can normally be reached M-F 730-330 PM.
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Eugene Lee
September 10, 2026
/EUGENE LEE/Primary Examiner, Art Unit 2815
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