Title:
PROTECTIVE COATING FOR LEAD FRAME USE
Document Type and Number:
Japanese Patent JPH05226543
Kind Code:
A
Abstract:
PURPOSE: To reduce the cost of solderable coating by using a solderable precious-metal deposit which is applicable to lead frame only for a finishing coating for covering a whole lead frame and a region to be soldered in a final assembly. CONSTITUTION: A copper IC lead frame is first coated with nickel, to provide an adequately appealing corrosion protecting finishing. Then a part of a lead frame used for soldering in a final IC assembly is subjected to a stop plating with a very thin film of palladium or an alloy of palladium, such as an alloy of palladium and silver. An IC is mounted on the lead frame, and fingers of the lead frame are wire-bonded to a sustaining pad of the IC. The above method has an advantage in cost by using spot-plated alloy of palladium, even for a package with a very large number of leads.
Inventors:
HEMU PII TAKIAA
RANJIYAN JIEI MASHIYUU
RANJIYAN JIEI MASHIYUU
Application Number:
JP31032492A
Publication Date:
September 03, 1993
Filing Date:
November 19, 1992
Export Citation:
Assignee:
NAT SEMICONDUCTOR CORP
International Classes:
C25D7/00; C25D7/12; H01L23/50; (IPC1-7): C25D7/12; H01L23/50
Attorney, Agent or Firm:
Kaoru Furuya (2 outside)