Micro heat spreader enhanced heat transfer in MCMs

The peak thermal power generated in microelectronics assemblies has risen from less than 1 W/cm/sup 2/ in 1980 to greater than 40 W/cm/sup 2/ today, due primarily to increasing densities at both the IC and packaging levels. We have demonstrated enhanced heat transfer in a prototype Si substrate with a backside micro heat channel structure. Unlike conventional micro heat pipes, these channels are biaxial with a greater capacity for fluid transfer. Thermal modeling and preliminary experiments have shown an equivalent increase in substrate thermal conductivity to over 500 W/m.K, or a four times improvement. Optimization of the structure and alternative liquids will further increase the thermal conductivity of the micro heat channel substrate with the objective being polycrystalline diamond, or about 1200 W/m.K. The crucial design parameters for the micro heat channel system and the thermal characteristics of the system are covered.