Study of Solder Resist Crack Resistance for Flip Chip Ball Grid Array Substrate

Study the methods to prevent the solder resist material of flip-chip ball grid arrays crack. Strategies of releasing the stored stress in substrate to improvement SR crack were demonstrated through process DOE. To observe the SR surface status and material properties after add an extra pre-curing process and fine tune the UV energy. The physical properties of SR film and the surface topography are same level. The adhesion between SR and ABF interface show no significant different. Observe the SR crack after difference TCT cycle times, the SR crack has been improved. A pre-curing process before UV curing is able to promote the solder resist crack resistance.