A silicon-diamond microchannel heat sink for die-level hotspot thermal management

A novel microchannel heat sink with an excellent die-level hotspot mitigation capability has been introduced for electronic cooling applications. The basic concept of the proposed composite design is based on the dissimilarity in the thermal conductivities of materials. The microprocessor area was divided into multiple zones of different heat fluxes and the heat sink was developed using dissimilar materials for each zone. Silicon was used for the low-heat-flux zone and diamond with substantially higher thermal conductivity (ten times higher than silicon) was used for the high-heat-flux zone. The non-composite design was completely made of silicon with the same geometric parameters. A comprehensive numerical analysis of the composite heat sink was carried out and the results were compared with that of the non-composite heat sink. Both heat sink designs were assessed at various flow rates, heating schemes, and hotspot sizes. The thermal resistance, temperature non-uniformity, and pumping power were calculated to assess the performance of both heat sinks. The proposed design exhibited a substantial performance enhancement without any increase in the pressure drop or pumping power. Besides, the composite design was analyzed by varying the diamond zone size while keeping the hotspot size fixed which showed further enhancement in its performance.