Chlorine effect on copper bonding wire reliability

Currently, wire bonding is still the dominant interconnection mode in microelectronic packaging. Copper (Cu) bonding wire is widely used due to its advantages, such as low-cost and good electrical conductivity. However, Cu wire bond is susceptible to galvanic corrosion. It is well known that Cu wire bond corrosion with the presence of moisture and chlorine (Cl). However, there is few reports on Cl effect on Cu wire bond at elevated temperature.This paper discusses the influence of Cl effect on the Cu wire bond. Different contents of Cl were purposely added into the epoxy molding compound (EMC). Accelerated reliability tests biased highly accelerated stress test (bHAST), temperature humidity ubias test (THT), and high temperature storage test (HTS) were conducted. The purpose is to compare the Cl effect on Cu wire bond reliability under different environments (i.e. temperature, humidity, voltage). It is found that Cl acted as a catalyst in IMC corrosion under humid environment. Cl also caused wire bond failure in HTS test if the Cl content is high. This work can serve as a reference to semiconductor engineers and scientist who use Cu wire bond.