Equivalent Thermal Conductivity Model Based Full Scale Numerical Simulation for Thermal Management in Fan-Out Packages

Abstract

Exploring along the road of More Moore with integration degree increasing significantly, different wafer level 3-D technologies are developed facing various circumstances. Thermal issue has become an important concern in IC designing and manufacturing. Fan-out wafer level package (FOWLP), as one of the most popular packaging trends lately, compared to high cost through silicon via (TSV) based 3D integration method, requires system level thermal management. Full scale numerical simulation as a critical procedure is facing huge difficulties, such as huge structure size variation, huge thermal properties variation, in-plane and off-plane displacement, etc. Equivalent thermal conductivity model (ETCM) based full scale numerical simulation for thermal management, which has already been applied to TSV based 3-D ICs with computation consumption significantly decreased, is applied to Fan-out packages in this paper. Equivalent and anisotropic thermal conductivity is calculated and modified concerning FOWLP structure and material thermal properties. A chip-first face-up fan-out package with 100 pads and 100 bumps is modeled and simulated, with mesh elements number drops from 874836 to 174810. With more than 80% computation consumption saved, less than 2% difference in total temperature rise is obtained compared with detail simulation.