Thermal modeling of Direct Bonded Heterogenous Integration (DBHi) MCM package with Si microcooler

Abstract

with the rapid advancement of high-density packaging technology, heterogeneous integration of multi-chip module (MCM) has emerged as a viable solution to achieve increasing demands for electronic device performance. Placing the multiple dies in close proximity enables high bandwidth, low latency, and low power consumption of the system. However, thermal management of such high-performance electronic device has become critical challenge associated with ever increasing power dissipation. Insufficient heat removal and large temperature gradient over the chip will seriously affect the reliability degradation. Previous study has demonstrated stacked silicon microcooler with single-phase liquid cooling as one of the effective solutions to address such thermal challenges. The thermal performance of the silicon microcooler was measured to be 32 mm2K/W at a flow rate of 25 mL/s while using single heat source with power of 600 W.This paper expands the prior work to MCM with four functional chips integrated in a single package and evaluated the cooling capability of silicon microcooler with new designs. Novel designs of stacked silicon microcooler subjected to MCM - namely inlet-centered flow cross-flow, counter-flow, and rotational-flow were developed and numerically analyzed using Computational Fluid Dynamics (CFD) simulation. Heat transfer performance and fluid flow behavior of these types of microcoolers were investigated and compared to the conventional microcooler with straight channel structure. In this work, two cases of heat source conditions were studied, (Case-A) four chips having identical power density, and (Case-B) four chips having different power density. Simulation result indicated that for Case-A, inlet-centered microcooler showed the best heat dissipation performance in terms of the maximum temperature rise and temperature uniformity of the chip. It also achieved the lowest pressure drop among the others. For Case-B, microcooler design which contains various flow directions, such as cross-flow or rotational-flow had superior thermal performance to the conventional microcooler.