Authors: Andrew Mawer, Chu-Chung (Stephen) Lee, Tu Anh Tran and Les Postlethwait Company: Freescale Semiconductor, Inc. Date Published: 10/14/2012
Abstract: For wire-bonded semiconductor packages, whether substrate or leadframe based, gold (Au) has been the traditional composition of choice for the bonding wire that forms the interconnect between the die and the package. A bond is made on the die pads by thermosonic bonding of an Au ball bond formed from the Au wire to the aluminum (Al) bond pad resulting in the formation of AuAl intermetallic compounds (IMC). In recent years, driven mainly by large increases in the cost of Au and potential reliability and performance advantages, the industry has seen a large increase in the use of copper (Cu) wire for wire-bonding [1-5]. This relatively rapid transition has not been without challenges and there are many aspects to the successful and reliable implementation of Cu wire-bonding in production. This paper will provide a detailed overview of the technology including its rewards and challenges.