Development of package level hybrid silicon heat sink for hotspots cooling

In this paper, the fabrication of package level silicon microchannel heat sink for hotspot thermal management is presented. These include the design, micro fabrication process and chip level integration of a hybrid silicon heat sink, which integrates jet impingement, microchannel cooling technologies. The fabrication of hybrid heat sink is proposed by bonding two Si chips which patterned with nozzle and microchannel structures separately. The nozzle array is fabricated using though silicon vias (TSV) process. This nozzle plate is used to generate jet impingement effect into the microchannel heat sink. On the other hand, the microchannel heat sink consists of micro fins and channels which are fabricated using deep reactive ion etch (DRIE) process. The micro fins increase the area for convective heat transfer while the micro channels serve as the liquid conduit to carry the intense heat away from the heat source. Two silicon chips are bonded using thermal compression bonding (TCB) process. For the packaging, the integration of thermal chip and diamond heat spreader onto silicon heat sink is performed using gold-tin eutectic bonding through TCB process. In this paper, the major fabrication steps and critical process parameters will be discussed in details along with the hydraulic test and thermal analysis.