ULTRAHIGH-CAPACITY MICROMACHINED HEAT SPREADERS

Micro heat pipes and microscale flat-plate heat pipes processed as an integral part of semiconductor devices are examined as an alternative to polycrystalline diamond or aluminum nitride (AIN) ceramic heat spre aders. We review several means that have been proposed for fabricating microscale heat pipe designs within electronic die or as substrate he at spreaders. We then report testing techniques and new experimental r esults for a silicon spreader design we developed. The results show th at incorporating these phase-change heat spreaders as an integral part of semiconductor devices significantly decreases the temperature grad ient across a chip and decreases the maximum chip temperature. Signifi cant process and production issues remain, but the test results clearl y show that this approach is a feasible alternative cooling technique that merits serious consideration for microelectronic heat transfer ap plications.