Thermal modelling, characterization and optimization of 2.5D heterogeneous integrated platform for RF front end

This paper studies the thermal characteristics of a compact 2.5D heterogeneous integrated platform by numerical simulation. The platform contains a silicon interposer carrying high-density power amplifiers made of gallium nitride on silicon carbide (GaN-on-SiC) and temperature sensitive passive filter dies. Comparing with traditional wire bonding method, the flip chip method suspended by metal stub enjoys greater benefits on RF performance. However, thermal issue becomes more challenging in this configuration due to the improper thermal transferring path. This work numerically studies the metal casing as a cooling solution and explores the potential capabilities in 2.5D heterogeneous integrated platform based on a full-scale 3D finite element model. Temperature distributions across the package in different conditions are presented to reveal the effect of the casing. And the parametric study results guide the thermal design of such casing in practice. The information in this paper could be helpful in the thermal design of 2.5D heterogeneous integrated platform for RF front end.