Effect of coupling agents on underfill material in flip chip packaging

in order to improve the adhesion property of underfill, coupling agents are widely used. In this study, three different silane coupling agents, two titanate coupling agents and one zirconate coupling agent were added into an epoxy underfill material. Their effects on the flow behavior and curing profile of the epoxy underfill were studied by rheometer and differential scanning calorimeter (DSC), respectively. The thermal stability of the cured underfill material was studied with thermogravimetric analyzer (TGA). Thermal mechanical analyzer (TMA) and dynamic mechanical analyzer (DMA) were used to measure the coefficient of thermal expansion (CTE), glass transition temperature (T-g), storage modulus (E'). in addition, the adhesion of the underfill on benzocyclobutene (BCB) passivated silicon die and polyimide passivated silicon die was measured by die sheer test. The effects of aging in 85 degrees C/85% relative humidity chamber on bulk properties and adhesion property were also evaluated through thermal analysis study and die shear test.