Microgap cooling of via-enhanced glass interposers

A series of single-phase water microgap cooling experiments (gap height: 200 μm) are conducted on via arrays in 400 μm thick glass interposers. Surface temperature rise is compared to trials run with bulk Si of the same thickness. The results show that the copper vias are necessary to control the temperature rise of the glass substrate, and that while the via-enhanced interposers do exhibit a larger thermal resistance than silicon, they also provide the desired increase in lateral thermal isolation. As flow rates within the gap are increased (approaching Re=1600), the penalty associated with constraining the flow of heat to the footprint of the via array is mitigated, owing to the reduction in the thermal resistance attributable to the convection boundary.