Evaluation of Impact Strength due to Thermal Degradation for BGA-IC Package

Abstract

The effects of 125°C holding time on static strength of package solder balls and the impact strength of package solder balls have been investigated for the BGA-IC package with Pb-free solder or Pb solder. Solder ball failure can be divided into ductile failure of solder balls and interface failure between a copper and inter-metallic compound. Results show that aging time increases the ductile strength of solder balls in a package and decreases the interface strength of the package. The impact strength of solder balls in a BGA package can be predicted from the static strength of the solder balls. The predicted impact strength of solder balls was compared with the actual impact strength of solder balls. It shows a good correlation.