The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 1992
Filed:
Jul. 25, 1990
Yasuyuki Nakamura, Suita, JP;
Kenji Hirano, Suita, JP;
Sumitomo Special Metal Co., Ltd., Osaka, JP;
Abstract
A heat-conductive composite material usable as a substrate (heat sink) for mounting a semiconductor thereon or a lead frame is provided, which comprises a core sheet and metal foil layers as welded to the both surfaces of the core sheet. The core sheet is composed of a metal sheet of high thermal expansion as sandwiched between two metal sheets of low thermal expansion each having a number of through-holes in the direction of the thickness, and the three layers are laminated and integrated so that a part of the metal sheet of high thermal expansion is exposed out to the metal surfaces of low thermal expansion through the through-holes of the metal sheets of low thermal expansion. The metal foil layers each are made of a metal of high thermal expansion, which are same as or different from the metal of high thermal expansion of constituting the core sheet. Varying the thickness ratio of the respective constitutional metal sheets and the surface area ratio of the exposed metal spots on the surfaces of the core sheet, heat-conductive composite materials having any desired thermal expansion coefficient and thermal conductivity can be obtained. Additionally, by providing the outermost metal foil layers on the both surfaces of the core sheet, the heat-conductive composite material has an improved uniform heat-receiving effect and an improved excellent heat-diffusing effect. Further, the material is free from fine pores on the both surfaces thereof and therefore has an excellent weldability.