Corrosion Failure Analysis and Reliability of Copper Wire Bonding of Pre-plated Frame

The second bonding site of copper wire bonding of pre-plated frame (PPF) of IC package was found to have failed during service. Laser unsealing and cross section analysis were carried out to analyze the failure cause, and it is found that the failure is related to electrochemical corrosion. 2 000 h of high temperature storage (HTS) test and high temperature & humidity storage (THS) test were conducted to study the failure mode of dry and wet corrosion of the copper wire bonding interface of PPF. Destructive analysis shows that: In the low humidity environment without Cl ions, electrochemical reaction rate was slow, and metal corrosion probability was low. In high humidity environment containing Cl ions, reaction rate greatly increased, and the corrosion severity and probability between copper wire and frame was the most prominent. High humidity and Cl ion concentration significantly accelerated the corrosion of metal interface, especially the copper wire.