Effect of Properties of Underfill Materials on Thermal Stress Relief in Lead-free Solder Joint of Chip Size Package

摘要

The effect of the mechanical and physical properties of an underfill material on thermal stress relief in a lead-free chip size package (CSP) solder joint has been investigated. Thin sheets of underfill materials for the CSP solder joint were prepared and the mechanical and physical properties of the sheets were investigated. Using these properties, thermal stress relief in an encapsulated CSP lead-free solder joint with the underfill material was examined by a finite element analysis method under thermal cycle conditions in the temperature range from 293K to 398K and 233K.