Designing Solder Alloys for Electronic Packaging

Lijia Xie, a graduate student at Purdue University, presented at the SCALE HIAP Lunch-and-Learn Seminar

Older alloys provide essential mechanical and electronic connections between semiconductor chips and the outside world - bringing power into the information into and out of the chips. Researchers, such as our Purdue team from MSE and ME and our industry collaborators, have been working for decades to design higher performance solder alloys for a wide range of applications, from aerospace and defense to advanced packaging for AI applications. Understanding the effects of alloying elements on thermal and mechanical reliability of alloys is important in alloy design and lifetime predictions for these different applications and under different service conditions. In this talk, I will describe the application of high-temperature solder (HTS) alloys ued in aerospace/defense applications and of low-temperature solder (LTS) used in the most advanced semiconductor packages. The focus of my talk will be our recent progress in HTS alloy design based on Sn-Ag-Cu (SAC)-based alloys and in Sn-Bi based LTS alloys are seen in our studies of microstructure evolution of solder interconnections under different conditions.