Jet Impingement Cooling Using Micro Channels in Low Temperature Cofire Ceramic (LTCC) Substrates

With power densities near 200 W/cm² for devices, new methods for thermal management from the heat generation at the die to heat removal to the ambient must be addressed. Signal interconnect and thermal management are often decoupled, with the I/Os from the substrate to the chip through flip chip solder balls and heat removed through the backside of the chip. However, interconnect substrates could provide both first level interconnect and fluid cooling thermal management. Providing micro channels in the same dimension as the interconnect pitch in the substrate allows for new and novel cooling methods to be integrated at the lowest level of chip assembly. X-Y micro channels less than 2 5 m wide and Z dimension channels 4 5 m wide were fabricated within the LTCC substrate. The integrated micro channels allow for direct jet impingement cooling. Initial thermal testing using single jet impingement demonstrated over a 200X reduction in thermal impedance.