Modeling and Simulation Challenges in Embedded Two Phase Cooling: DARPA’s ICECool Program

Modeling and simulation of two-phase phenomena, as well as their impact on electrical performance and physical integrity are critical to the success of embedded cooling strategies. In DARPA’s Intrachip/Interchip Embedded Cooling (ICECool) program, thermal/electrical/mechanical co-simulation and modeling tools are being applied to the analysis and design of RF GaN MMIC (Monolithic Microwave Integrated Circuit) Power Amplifiers (PA) and digital ICs, with the ultimate goal of achieving greater than 3X electronic performance improvement. This paper addresses various simulation strategies and numerical techniques adopted by the DARPA ICECool performers, with attention devoted to co-simulation through coupled iterations of thermal, mechanical and electrical behavior for capturing device characteristics and predicting reliability and “best in class” simulations that can provide an understanding of device behavior during rugged operating conditions impacted by multi-physics environments. The effect of CTE (Coefficient of Thermal Expansion) mismatch on bond and structural integrity, the impact of cooling fluid choice on performance, the factors affecting erosion/corrosion in the microchannels, as well as electro-migration limits and joule heating effects, will also be addressed. A separate discussion of various two-phase issues, including interface tracking, system pressure drops, conjugate heat transfer, estimating near wall heat transfer coefficients, and predicting CHF (Critical Heat Flux) and dryout is also provided.