Transistor cooling by heat pipes having a wick of dielectric powder

A microelectronic package capable of operating with power densities extending at least to 10 kW/cm.sup.2 comprising:

• means for defining a sealed enclosure coupled to an external heat sink;
• means for defining electronic devices and circuitry sealed within said enclosure means;
• electrical coupling means from said electronic devices and circuitry means and extending outside of said enclosure means for electrically coupling said electronic devices and circuitry means to further electronic circuits;
• means including dielectric powder adhered substantially to all interior surfaces of said enclosure means and to all exposed surfaces of said electronic devices and circuitry means for defining a heat pipe wick substantially completely and conformally coating said interior and exposed surfaces;
• and
• means for defining a dielectric working fluid in said enclosure means and intimately contactable with all said interior and exposed surfaces, thereby for minimizing the occurrence of local hot spots on said electric devices and circuitry means and for maximizing heat transfer therefrom to said external heat sink.