Development of a Polyimide/SiC-Whisker/Nano-Particles Composite with High Thermal Conductivity and Low Coefficient of Thermal Expansion as Dielectric Layer for Interposer Application

摘要

2.5D Si interposer with finer through silicon via (TSV) and high density interconnections on the redistribution layer (RDL) is increasingly widespread applied in system in packaging. A promising design, composite film of Polyimide with SiC-whisker and particles, is adopted as the dielectric layers of the RDL. The proposed composite material serving as dielectric layers possess higher thermal conductivity and smaller thermal expansion mismatch with the conducting layer (electro-plating Cu) of the RDL and Si substrate. By using this proposed composite material as the dielectric layers of the 2.5D Si interposer interconnecting a functional chip (10W/cm2), the thermal gradient was reduced by 84.5 %, the maximal von Mises stress was decreased by 21 %, and thus, the thermal mechanical reliability has been remarkably improved.