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:
Mar. 28, 1978
Filed:
Mar. 18, 1977
Nicholas George Koopman, Hopewell Junction, NY (US);
Paul Anthony Totta, Poughkeepsie, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A circuit package exhibiting an excellent heat transfer path from a semiconductor chip or other heat-generating device to the heat-sink can or cover of the package. A heat-conducting pad is metallurgically bonded to either said cover or a surface of said device; the pad is also separably attached, but metallurgically unbonded, to the other. In one preferred embodiment, a readily deformable metal or alloy, such as indium, is metallurgically bonded to a limited central region of the heat sink cover. The deformable metal is separably attached to a major surface of the chip so that there is no stress between the chip or its joints and the solder during the electrical operation of the chip when it generates heat. The preferred method of fabrication involves the mechanical deformation of a mass of solder against the back side of the chip, after the solder has been metallurgically bonded to heat sink. The process may be accomplished either at high or low temperatures, depending upon the solder composition and the relative strength of the leads which join the chip to conductive lands on its supportive substrate.