Study on effect of coupling agents on underfill material in flip chip packaging

Coupling agents are widely used in order to improve the adhesion property o f underfill. In this study, three different silane coupling agents, two tit anate coupling agents, and one zirconate coupling agent were added into an epoxy underfill material. Their effects on the flow behavior and curing pro file of the epoxy underfill were studied with a rheometer and a differentia l scanning calorimeter (DSC), respectively. The thermal stability of the cu red underfill material was studied with a thermogravimetric analyzer (TGA). A thermal mechanical analyzer (TMA) and a dynamic mechanical analyzer (DMA ) were used to measure the coefficient of thermal expansion (CTE), the glas s transition temperature (T-g), and the storage modulus (E'). In addition, the adhesion of the underfill on benzocyclobutene (BCB) passivated silicon die and polyimide passivated silicon die was measured through die shear tes t. The effects of aging in an 85 degreesC /85% relative humidity chamber we re also studied through moisture absorption test and die shear test.