Thermal management of 3D chip with non-uniform hotspots by integrated gradient distribution annular-cavity micro-pin fins

Abstract

Targeted at addressing practical thermal issues of 3D-IC chip, heat transfer characteristics and temperature uniformity of gradient distribution solid and annular-cavity micro-pin fins are experimentally and numerically investigated. At double side non-uniform heat flux condition (qb/qhs of 40/300 W/cm2), a significant deterioration of heat transfer is found with maximum temperature gradient of 44.6 K. With respect to uniform design, gradient distribution solid pin-fin chip provides considerable potentials to address a large hotspot heat flux (700 W/cm2) and improve temperature uniformity with a relatively small hotspot size (<200 * 200 μm). Further thermal-path analysis reveals that pin-fin surfaces act as a key role to transfer and redistribute the heat with transferring more than 64% of heat into the fluid. To address critical multiple heat flux condition, novel gradient distribution annular-cavity pin fins are designed to increase heat transfer area and eliminate flow dead zones. Applying two-side symmetrical inlet cavity, the coolant from micro-channel like rushes into the center cavity and forms local acceleration to impinge the next pin-fins. The combined effect of increasing heat transfer area and forming acceleration zones leads to a maximum reduction of the local hotspot temperature and total thermal resistance by 9 K and 34.5%, respectively.