Silver glues and lead-free alloys in die attach of power devices

Environmental, health and safety regulatory, as well as consumer pressure, have pushed industry to remove lead from electronic products. Soft solders used for die bonding (die attach) is the more critical for replacing. The increasing of peak temperature that the packages must withstand limits the number of commercially competitive alloys that can be use as lead free solders for die bonding. Combining the requirements of solder's high melting point with its workability and reliability needs, leaves none of the investigated alloys results as suitable alternatives to solders containing lead (Del Bo et al., 1997). On the other hand, it was found that recently developed glues exhibit electrical and thermal performances that are competitive with leaded alloys for die bonding of power packages. Moreover, reliability and process control are improved enough to propose glue material also for power application. In this article, the most significant results of these investigations are presented.