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:
Nov. 07, 1989
Filed:
May. 23, 1988
William P Dugan, Glendora, CA (US);
Rama P Samudrala, Upland, CA (US);
Grace A Rivas, Claremont, CA (US);
General Dynamics Corp., Pomona Division, Pomona, CA (US);
Abstract
A process for producing a copper lead frame tape in which the individual fingers of the lead frame are provided with gold plated bumps. A copper foil is provided with dry film photoresist on both sides and is initially processed to provide openings in one side of the resist for electroforming of the end products directly on the copper foil. Further processing produces openings on the other resist side in locations other than opposite the first resist side bumps whereby a following chemical milling of the exposed opposite side copper yields a plurality of fingers, each consisting of an integral bump/copper foil arrangement. The electroforming step is made possible by a novel double-cell electroplating method in which a relatively high-impedance ion path connects the two cells. Bump heights of as much as 0.0013 inch or greater are produced by the disclosed process, with uniformly excellent quality.