Metal Additive Microfabrication of System-in-Package with Embedded Microfluidic Thermal Management for Heterogeneous Integration with Semiconductor Dies

The scaling of components on a single semiconductor chip has enabled the doubling of performance every 2 years as per Moore's law, and has been possible due to the miniaturization of individual components. A significant decrease in transistor gate length and increase in component density has also introduced an increase in power density. Hence, there is a dire need for embedded thermal management of these systems-on-chips (SoCs) to remove waste heat. In this work, the metal additive microfabrication of a system-in-package (SiP) package with multiple pads for quad flat no-lead (QFN) packaging and a microfluidic channel and pin fin heat sinks for thermal management are presented. This work introduces heterogeneous integration (integration of separately manufactured components into a SiP for improved functionality) of SiPs fabricated using additive microfabrication to clean-room-fabricated integrated circuits (ICs) for improved functionality in terms of the thermal management of high-power density SoCs. The packages have been fabricated via a metal additive manufacturing technique, direct metal laser sintering (DMLS), using 316L stainless steel as the precursor powder. The work also opens doors to the fabrication and integration of metal microsystems using DMLS to complement semiconductor manufacturing and packaging processes. The use of air or water as the coolant for the packaging devices decreased the thermal resistance from 5.25 degrees C/W for the conventional packages to 2.02 degrees C/W for a flow rate of 84 mL/min when subjected to a constant heat flux. The average surface temperature also decreased from 45.61 degrees C to 29.23 degrees C for the same parameter. This article details the material characteristics and thermal performance of the metal additively microfabricated SiPs.