Leadframe and method of manufacturing the same

Abstract

A leadframe is plated with palladium only to a surface of a metal plate on which semiconductors elements are to be mounted and a surface of the metal plate to be placed on a substrate, and is not plated with palladium to lead portions, pad portions, other portions except for the surfaces to be plated and the side surface, of the leadframe, thereby, the amount of use of palladium is reduced to minimum and a cheap leadframe can be provided.

1 . A method of manufacturing a leadframe, comprising the steps of: 
 preparing a leadframe material by forming a metal plate,    plating palladium to necessary and minimum portions of said leadframe material on which semiconductor elements are to be mounted,and    plating palladium to portions to bond gold wires and necessary and minimum portions to be soldered of a surface to be placed on a printed circuit board, of said leadframe material.    
     
     
         2 . A method of manufacturing a leadframe, comprising the steps of: 
 preparing of a leadframe material by forming a metal plate,    plating palladium only to a surface of said leadframe material on which semiconductor elements are to be mounted, and    plating palladium only to a surface of said leadframe material to be placed on a printed circuit board, excepting lead portions, pad portions, other portions except for said surfaces to be plated and the side surface, of said leadframe material.    
     
     
         3 . A method of manufacturing a leadframe, comprising the steps of: 
 preparing a leadframe material by forming a metal plate,    Plating palladium only to necessary and minimum portions of a surface of said leadframe material on which semiconductor elements are to be mounted, and    plating palladium only to necessary and minimum portions of a surface of said leadframe material to be placed on a printed circuit board, excepting lead portions, pad, portions, other portions except for said surfaces to be plated and the side surface, of said leadframe material.