The development of effective model for thermal conduction analysis for 2.5D packaging using TSV interposer

Abstract

The effective model for the orthotropic TSV (Through Silicon Via) interposer in heat conduction for 2.5D IC integration was proposed in this study. The simple parallel model was used in out-of-plane direction to predict the effective thermal conductivity for the TSV interposer. The in-plane effective thermal conductivity for the interposer was derived on basis of heat balances. By introducing the effective orthotropic thermal parameters, the TSV structures can be ignored in the present effective model. The computations using the effective model for TSV interposer and the 2.5D package with interposer were carried out. The results showed that the accuracy of the effective model was above 95% comparing with the real model including TSV structures when the volume ratio of the electroplating copper and the silicon interposer is smaller than 10%. Using the effective model, the parametric studies on the interposer sizes and the thermal conductivities of different materials in the 2.5D package were conducted with higher efficiency. The results showed that the performance and sizes of EMC (Epoxy Molding Compound) and the package substrate are more important than that of internal underfills in heat dissipation of the package with TSV interposer.