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:
Oct. 10, 2000
Filed:
Feb. 04, 1998
Yoichiro Hamada, Ohkuchi, JP;
Sumitomo Metal Mining Co., Ltd., Tokyo, JP;
Possehl Sumiko Electronics Singapore PTE Ltd., Jurong, SG;
Abstract
A process for producing lead frames having lead tips with a minimum of side etching includes the steps of coating a metal lead frame substrate with a first photosensitive film, patterning the first photosensitive film, developing the patterned first photosensitive film, partially etching the metal surface of the lead-frame substrate beneath the developed patterned first photosensitive film, coating the partially etched metal surface with a positive second photosensitive, exposing the positive second photosensitive film to light passing through the developed first photosensitive film, developing the exposed second photosensitive film, performing fine etching through the developed second photosensitive film to a desired depth at least once, and removing the first and second photosensitive films.