Evaluation of Different Die Attach Film and Epoxy Pastes for Stacked Die QFN Package

The trend in the semiconductor industry is to develop more powerful components while decreasing the component size. A suitable material set has to be obtained for the required reliability performance. The objective of this study is to evaluate the performance of different die attach film (DAF) and epoxy pastes for stacked die quad flat no-lead package. Both experimental and modeling works are resorted to analyze and refine the package design. Six combinations of die attach materials are evaluated to compare with current single die package. The strengths and weaknesses of the DAF and epoxy paste are compared in this paper. Die shear test is performed to study the adhesion condition between the die attach material and silicon die. Finite element model of the package is generated to determine the thermally induced stresses under different conditions. All the results show that it is robust to use the new epoxy paste and DAF.