The Effect of Thermal-Induced Warpage and Degeneration of Thermal Interface Materials on the Thermal Performance of a Flip-Chip Package

With the continuous and rapid development of microelectronics technology, the power consumption of microelectronic device increased with the improvement of performance. The increasing power consumption may cause thermal-induced failures and greatly affect the reliability of the device. To avoid this problem, heat sinks and thermal interface materials (TIMs) are used for effective thermal management. The TIM1 is used inside the device between the chip and the metal lid to eliminate the interstitial air gaps from the interface by conforming to the topography of the surfaces in contact. However, in practical application, TIM1might be affected by thermal-induced deformation, resulting in the change of bond line thickness (BLT), loss of corner areas, and increase of interface thermal resistance, which may have a significant impact on the heat dissipation in return. In this paper, the effect of TIM1 on the junction temperature of chip in a flip-chip structure with heat sink and fan are systematically investigated using computational fluid dynamics (CFD) method. The temperature profile is obtained and the heat transfer in the out-of-plane and in-plane directions are analyzed. The effect of reduced in TIM1 coverage, warpage-induced change in bond-line-thickness (BLT) and contact resistance are discussed in detail.