BGA electromigration behavior and why it has become the bottleneck

Abstract

Current densities for high-performance applications (such as AI/ML, Artificial Intelligence/ Machine Learning) have continued to increase to levels never seen before. Power consumption of modules in advanced nodes are starting to exceed 1 kilowatt, resulting in critical current values through the power-delivery path. Due to improvements in 1st level interconnect technology, the weakest link is now moving to the 2nd level interconnect, i.e. the BGA's. This work demonstrates the current-carrying capability of BGA's under a variety of different conditions, including substrate design, pad finishes and solder materials, and process variations. Thermal/electrical simulations were used to guide the design and experiment setup and have been validated with subsequent experimental results. The results provide confidence for stretching BGA solder ball design rules up to 3A per connection when optimized design and material combinations are selected.