Thermal model for embedded two-phase liquid cooled microprocessor

Abstract

Chip embedded two phase evaporative cooling is an enabling technology to provide intra-chip cooling of high power chips and interlayer cooling for 3D chip stacks. Utilizing an interconnect-compatible dielectric fluid provides a cooling solution compatible with chip to chip interconnects for future high power 3D chip stacks. However, lack of high fidelity and computationally manageable conjugate thermal models limits the development of this technology. To address that, a thermal model for fast and accurate prediction of thermal and electrical behavior of an embedded two-phase liquid cooled micro-processor module is described in this paper. This model consists of a state-of-the-art conjugate heat transfer model for two-phase flow boiling through chip embedded micron-scale channels and a physics-based empirically tuned electrical model of the microprocessor. Extensive model validation using data from several experiments was performed to quantify the accuracy of this model under different operating conditions (including various chip operating frequencies and coolant mass flow rates). Results showed that this model can predict the electrical behavior as well as two-phase flow and heat transfer characteristics with very good accuracy. Overall, the chip junction temperature predictions were within two degrees of the experimental data and the temperature-dependent chip power predictions were within 10%.