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:
Jun. 22, 1993
Filed:
Sep. 06, 1991
Applicant:
Inventors:
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B44C / ; C23F / ;
U.S. Cl.
CPC ...
156652 ; 29827 ; 156656 ; 1566611 ; 156644 ; 156901 ; 437220 ; 257666 ;
Abstract
A method for producing a lead frame which comprises selectively forming a photoresist film on both sides of a lead frame material of three-layered structure, with an etching stop layer interposed between two metal layers, etching both sides thereof using the photoresist film as a mask, and removing the unnecessary part of the etching stop layer.