Metal Additively Microfabricated SiPs with Embedded Microfluidic Cooling Towards Heterogeneous Integration with SoCs

Present trends towards compact and high- performance system-on-chip (SoC) have been achieved by decreasing the gate length allowing the increase in component density on a single chip. Such demands of performance, scaling, and the use of wide bandgap semiconductor devices have resulted in increased power density as well as the hotspot power density. The development of such hotspots in the channels of semiconductor devices increases the overall temperature of the chip and consequently degrades the performance, reliability and function lifetime of the respective devices. Hence, thermal management of semiconductor devices is necessary for removal of heat from such hotspot as well as to assist heterogeneous integration of devices which has been limited only to low power chips due to lack of embedded thermal management. There are several levels of integration for thermal management, however this paper deals with the package-level thermal management of chips. This paper presents metal additively microfabricated System-in-Package (SiP) with embedded microfluidic thermal management towards heterogeneous integration with high-power system-on-chips (SoCs), in response to the SiP-level thermal management proposed by Heterogeneous Integration Roadmap (HIR) 2021. Direct Metal Laser Sintering (DMLS) was the major microfabrication tool for the manufacturing of the aforementioned packages where three dimensional (3D) metal packages were directly build based on computer-aided design (CAD) file using 316L stainless steel precursor powder. The proposed packages were able to decrease the thermal resistance to 1.1°C/W from 5.25°C/W (for conventional packages) employing single-phase water cooling. Optimization of microfluidic structures, which has been discussed in this paper, led to the improvement of thermal resistance compared to previous work.