Method for obtaining a palladium surface finish for copper wire bonding on printed circuit boards and IC-substrates

摘要

The present invention relates to a method of bonding a copper wire to a substrate, particularly a printed circuit board and an IC-substrate, possessing a layer assembly comprising a copper bonding portion and a palladium or palladium alloy layer and a substrate having a copper wire bonded to aforementioned layer assembly.

主权项

1. A method for forming a copper wire on a substrate, said substrate having at least one wire bonding portion made of copper or copper alloy comprising the steps of
(i) providing a substrate having at least one wire bonding portion made of copper or copper alloy; (ii) forming a palladium layer on the at least one wire bonding portion, wherein the palladium is deposited from an electroless (autocatalytic) plating palladium bath comprising a palladium ion source; a complexing agent; a reducing agent and wherein the palladium content is more than 99.9 wt-%; and thereafter (iii) bonding a copper wire onto the palladium layer.