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:
Dec. 13, 1994
Filed:
Oct. 28, 1993
Sheila J Konecke, Leesburg, VA (US);
Frederick G Weindelmayer, Manassas, VA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
In manufacturing packaged modules for computer systems, many modules require sealing a lid to a lower substrate by using solder around the outer edges of the lower substrate. When the solder is heated, it often flows inward towards the chips on the substrates (solder intrusions) and may cause shorts. This invention solves the problem of solder intrusions by using a graphite lid seal fixture during lid seal. The fixture is comprised of lower and upper parts. The substrate, which has a sealband area, rests on and is held in place by the lower part of the fixture. The upper part of the fixture rests on the lower part. The lid, which has solder on its lower surface which is slightly smaller but otherwise generally matches the sealband area of the substrate, fits in a hole in the upper part and rests on the substrate. Thus, graphite substantially surrounds the edges where the lid and substrate meet and the fixture evenly distributes the heat around the sealband during reflow so that the solder can flow out towards the edge of the sealband. By this means, areas where solder flows back into the interior of the module are reduced and hermeticity yields are improved.