Thermal and reliability analysis of clip bonding package using high thermal conductivity adhesive

Increasing demand for high switch speed of high power semiconductor modules requires better packaging solutions to improve the signal quality and reliability. Clip bonding technology can meet this requirement and is widely being used. Clip bonding makes the connection area between die and leadframe much bigger than gold wire bonding, and therefore reduces the inductance of the circuit, increases the information-noise ratio and reduces the voltage loss through circuit. Conventionally, high-lead solder is employed for clip bonding due to its high thermal conductivity, good reliability, and high bonding strength. With increasing concerns of environmental protection, leadless bonding materials, including high thermal conductivity adhesives, are considered to be the future mainstream. Surprisingly, little research has been conducted to systematically evaluate the thermal performances of clip bonding packages using high thermal conductivity adhesive, particularly for the packages after reliability tests. In this study, a commercially available high thermal conductivity adhesive was applied as bonding materials for high power package. The thermal performances before and after different reliability tests were evaluated and discussed by experiments and finite element simulation. Besides qualitatively evaluation, an analytical model was applied to quantitatively assess the reliability of clip bonding packages.