Structural Analysis of Electronic Packaging Considering Viscous Deformation of Lead Free Solder

Abstract

Viscoplastic deformation of solder alloys was experimentally observed. Pure tensile tests with several strain rates, creep tests, and stress relaxation tests were conducted using both Sn-37Pb and Sn-3.5Ag-0.75Cu solder alloys at several temperatures. The test results showed that the Sn-3.5Ag-0.75Cu solder alloy has lower viscosity than Sn-37Pb. The lower viscosity of the solder alloys causes larger bending of electronic devises due to temperature chang during the reflow process. Then FEM analysis was also conducted to clear the difference of the bending of the electronic devises using Sn-3.5Ag-0.75Cu and Sn-37Pb solder alloys.