Bonding Effect of Metal Thermal Interface Material on Oversized Flip Chip Package

Efficient heat dissipation is a major challenge for large flip-chip package with high power consumption. Due to its high thermal conductivity, metal lid is commonly found as a thermal interface material (TIM) between the die and the environment. In this work, a method for evaluating performances of ultrathick metal TIM is proposed. It is based on Non-destructive scanning acoustic tomography (SAT) with two interface waves for the constant-depth scan (C-scan) and a transmission scan (T-scan). In addition, the deterioration of the TIM bonding during reliability tests was also analyzed. Finally, a scheme to enhance the TIM bonding performances is proposed.