Program Summary
Three-dimensional heterogeneous integration (3DHI) currently employed in microsystems is limited to stacking of low-power logic tiers. Successful stacking of multiple high-power logic, radio frequency, and other functional tiers promises to unleash unprecedented advancements in military and commercial microsystems capabilities. This is currently not feasible, due in part to insufficient thermal management capabilities limiting in-plane and out-of-plane heat acquisition from each tier, poor thermal isolation between functional blocks, and unacceptably large heat transmission and rejection hardware. Minitherms3D aims to deliver a >3x reduction in overall thermal resistance, and a >2x increase in volumetric thermal management capability.
To achieve these objectives, Minitherms3D will focus on two technical challenges. The first addresses mitigation of thermal resistances within the 3D stack: increasing in-tier heat transfer without increasing tier thickness, thermal isolation between adjacent in-plane and out-of-plane functional blocks, and heat removal from each tier while maintaining low thermal resistance. The second challenge addresses mitigation of thermal resistance external to the 3D stack: reducing link thermal resistance from 3D stack to the heat rejection component and increasing volumetric heat rejection capability while reducing heat rejection resistance to ambient air. The program seeks to develop a compact thermal management technology for a 3DHI system with five equally powered tiers dissipating a total of 6.8 kW to a heat rejection system of less than 0.006 m3.