Investigation of Heat Dissipation and Electrical Properties of Diamond Interposer for 2.5-D Packagings

In 2.5-D packaging, thermal aggregation and signal crosstalk have been major obstacles in the development of high-density interconnect technology, greatly impacting the reliability of devices. This work presents a polycrystal/monocrystal diamond interposer with excellent thermal conductivity and low dielectric constant as a substitute for the Si interposer, aiming to address both thermal and electrical issues simultaneously. The thermal and electrical characteristics of Si, glass, and diamond interposers are investigated by analyzing heat transfer, heat dissipation, and electrical characteristics. The results show that diamond interposers are expected to effectively improve the heat transfer effect with the equivalent thermal conductivity of through-diamond via (TDV) cell always greater than 1200 W/m $\cdot $ K. The overall thermal resistance and peak temperature of the polycrystal diamond interposer drop by $0.75~^{\circ }$ C/W and $23.9~^{\circ }$ C compared to Si, respectively. The improved temperature uniformity of diamond interposer helps to reduce the risk of mechanical failure and delay of the chip. Furthermore, the peak transmission coefficient in TDV cell is -0.24 dB, which experienced a lower return loss compared to through-silicon via (TSV). Diamond interposers provide effective solutions for thermal management and signal crosstalk in 2.5-D packages, making it a promising candidate in the field of highly reliable packaging.