Improvement of Brittleness for Maleimide Molding Film and Package Level Reliability

We investigated to improve a brittleness of molding film including a maleimide resin for wide band semiconductor packages by replacing a rigid molecular framework with a flexible molecular framework. Fracture strain of them showed more than 2 times that of the rigid maleimide film by bending test. Furthermore, they showed excellent high temperature storage stability that was indicated peeling test after 200 °C for 1000 hours. Besides, package level reliability tests were carried out, Moisture Sensitivity Level 1 (MSL1) and Temperature Cycle Test (TCT) between −55/175 °C for 1000 cycles were passed. However, crack defects occurred in packages having a lot of flexible component in TCTat −55/200 °C. The defects were analyzed by Scanning Acoustic Tomography (SAT) and SEM, and revealed that cracks were occurred in the singularity point of stress.