Temperature and Stress effects on IMC Behavior of Thin Film Cu-Al System in Wire Bond

Wire bond is widely accepted as a predominant method for the area of electronic packaging. In this paper, authors focus on the nanoscale interfacial characteristics of thermosonic copper ball bonding on the aluminum metallization. A series of examinations and a 2.5D finite element simulation have been designed to find the IMC generation and the stress distribution. By TEM and SEM analysis, it was found at different temperatures, the IMC layers showed great difference in the thickness. By XRD and TEM analysis, the IMC also show different structures. By the finite element analysis, authors found the stress distribution when copper was bonding on the aluminum pad. By doing the research, people can have a general idea of the proper temperature and force when using copper wire bond.