Die Attach Film Performance in 3D QFN Stacked Die

Consumer demand for smaller and lighter products in wiresless application with maximum functionality had drive the semiconductor industries toward the developement of 3-dimensional stacked die. One of the key technology is relies on die stacking process. A suitable bonding condition and material set are essential to achieve required reliability performance. This study is to relate the effects of variables bonding parameter on the mechanical adhesion and delamination of the die attach film in QFN stacked die. Samples are deliberately built with nine combination sets of die attach parameters including bonding temperature, force and time to achieve a minimum reliability performance under IPC/JEDEC Moisture Sensitivity Level 3 at reflow 260°C. Characterisation of die attach film was carried out using differential scanning calorimetry whereas it performance was carried out using shear testing machine and scanning acoustic test (SAT) is used to detect the interfacial delamination between DAF and die. The best die attach process is characterized by stable values of die attach film thermal resistance properties and optimum touch area between die/die attach film and die attach film/die. Key-words:Die attach film, QFN, delamination