thermal analysis of a 3d die-stacked high-performance microprocessor
3-dimensional integrated circuit (3D IC) technology places circuit blocks in the vertical dimension in addition to the conventional horizontal plane. Compared to conventional planar ICs, 3D ICs have shorter latencies as well as lower power consumption, due to shorter wires. The benefits of 3D ICs increase as we stack more die, due to successive reductions in wire lengths. However, as we stack more die, the power density increases due to increasing proximity of active (heat generating) devices, thus causing the temperatures to increase. Also, the topmost die on the 3D stack are located further from the heat sink and experience a longer heat dissipation path. Prior research has already identified thermal management as a critical issue in 3D technology. In this paper, we evaluate the thermal impact of building high-performance microprocessors in 3D. We estimate the temperatures of a planar IC based on the Alpha 21364 processor as well as 2-die and 4-die 3D implementations of the same. We show that, compared to the planar IC, the 2-die implementation and 4-die implementation increase the maximum temperature by 17 Kelvin and 33 Kelvin, respectively.
thermals power density 3d technology