Enhanced bonding intensity between the vertically aligned carbon fiber thermal interface material and heat spreader of a flip-chip package through a silane coupling agent

Flip chips have been widely used in microelectronic packaging to meet the requirements of high density and optimal performance; the thermal interface material (TIM) is the primary bottleneck for heat dissipation in flip-chip packages. Vertically aligned thermal pads offer higher thermal conductivity compared with thermal gels, yet their poor interface bonding strength makes their application challenging. In this study, a silane coupling agent (KH550) was applied to improve the bonding strength between the TIM and heat spreader (HS). The presence of the silane coupling agent intermediate layer enabled the TIM and HS to be connected <i>via</i> covalent bonds, greatly improving their bonding strength. The shear strength of the interface between the TIM and HS was increased by 610.7%, and the interface thermal resistance was decreased by 52.78%. Moreover, molecular dynamics simulation was conducted to investigate the interface bonding mechanism.