A Novel Approach for Cooling Chiplets in Heterogeneously Integrated 2.5-D Packages Applying Microchannel Heatsink Embedded in the Interposer

In this article, an innovative approach to enhance heat transfer mechanisms in 2.5-D heterogeneous packages by integrating microchannels into the silicon interposer is presented. An analytical model is introduced to determine the main thermal properties of the cooling system. To demonstrate the cooling performance of the device, a 3-D model is created, and a total of 12 cases for four scenarios are investigated numerically. The results are compared with the classical cooling approach applying 10-100 cm3/min water flow in the microchannels. It is demonstrated that in the case of a heterogeneously integrated system, incorporating a single-core chiplet as a central processing unit, the temperature dropped from 109 ? to 44 ? at the highest flow rate by applying the combination of the conventional heat sink and the integrated microchannel cooler. It is also shown that regarding a system with a four-core processing unit when only one core has a high load, the core temperature decreases by up to 72.7 ?. The contribution of the enhanced secondary heat flow path is obtained from computational fluid dynamics (CFD) simulation cases. The study shows that the importance of the secondary heat flow path has increased significantly, and the proposed novel cooling system can solve the thermal issues of the heterogeneously integrated 2.5-D devices.