Thinnest is best in thermal management

Problem: . At the same time, higher clock speeds mean CPU and other logic devices produce more heat. In 1998, such devices produced 10 to 40W whereas today, a 3GHz processor can be expected to produce 250W and by 2010, predicted 1 billion transistor devices are likely to have to dissipate 600W. It is already possible to fry an egg on a processor heat sink, as demonstrated in an experiment described at http://www.hex-tech.co.uk/egg.asp, but this is not a practicable long term solution to such problems. Solution: Chris Palin, the European sales manager of Thermoset, argues that part of the solution is to come up with heat transfer compounds that not only have a good thermal conductivity, but also the lowest possible viscosity and the best possible wetting characteristics when applied. Such combinations lead to thinner layers of compound and reduced thermal impedance, a measure of how well heat can make it from device to heat sink per unit contact area. Latest developments include an SC-320 low viscosity, 3W/moK thermal conductivity encapsulant. The compound has very low viscosity in order to ensure that when poured, it fills all nooks and cavities and achieves maximum contact area. The company already offers high thermal conductivity, low thermal impedance 'Gelease' that dispenses like grease but cross links. Thermal conductivities are >2.1W/moK but because the material can made to form a bond line only 1 mil (25 micron) thick, thermal impedance is down to 0.06oCm2/W. Applications: SC-320 is designed for any general potting use. Gelease is especially useful for providing thermal contact between silicon dies and the insides of packaging in Flip Chip applications. TS Egg frying experiment Thermoset Advanced Electronic Materials