Thermal Impact of Heat Spreader Co-Planarity to Electronic Packaging

Abstract

This study presents the thermal impact of heat spreader co-planarity on the flip chip package with heat spreader. The co-planarity of heat spreader changes the thermal performance of the flip chip package significantly, especially the junction-to-case thermal resistance of the package. A numerical study using ANSYS Icepak was conducted to investigate the thermal degradation of heat spreader with concave and convex deflection up to 0.12 mm. The result indicates that the concave deflection causes improvement while convex deflection causes degradation in junction-to-case thermal resistance of the flip chip package. The outcome of the study recommends the co-planarity tolerance for the heat spreader shall not be greater than 0.07 mm for a 60 mm x 60 mm flip chip package with the dissipation power of 150 W.