Reliability of palladium coated copper wire

Alternative solutions for Au wire are high in demand as a result of increasing gold price and high demand for lower cost packages. Copper wire has been the natural low cost alternative but concerns on corrosion susceptibility and package reliability have driven the industry to look for better alternative wire materials while maintaining substantial material cost savings. PdCu wire is supposed to close this gap and serves a promising solution for applications that require cost effectiveness (still significant cost saving over gold) and robust bonding performance (closer to that of gold wire). One critical question in the industry currently is, whether or not PdCu wire can address the reliability concerns, which are occurring at some copper wire applications in the field. This paper will cover the intermetallic phase growth of PdCu wire on Al pad metallization at as bonded condition and tries to understand whether or not there is any difference at the interface compared to bare copper, during initial bonding and during reliability testing like HTS, HAST and PCT.