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:
Jul. 10, 1984
Filed:
May. 16, 1983
Raymond L Dietz, Poway, CA (US);
Michael Featherby, San Diego, CA (US);
Peter K Margetts, El Cajon, CA (US);
Johnson Matthey Inc., Malvern, PA (US);
Abstract
A silver metallizing paste for attachment of silicon semi-conductive devices in lead-frame packages, specifically ceramic packages, which is less expensive than a gold preform but useable in hermetic packages, and provides better electrical and thermal conductivity, and higher bond strength, than silver polyimides. From 25 to 95% of silver is blended with a low-melting glass, preferably one having 95-96% PbO, and a paste or ink is formed with a suitable vehicle at 75-85% solids. Use of the paste follows conventional practice. Selection of Ag:glass ratio depends on the type of die bonding to be used. The paste is particularly useful in MOS technology, where low contact resistance is required, and also finds applications as a solder substitute and bonding chip capacitors. It is most advantageous in attachment of larger-area integrated circuits in that stress cracking associated with the gold-silicon eutectic is avoided.