An apparatus and method for cooling electronics is disclosed. An
encapsulated inert non-conductive fluid is used to transfer heat directly
from an electrical circuit including a die on a substrate to an external
heatsink. The top of a flip chip die (e.g. a ceramic column grid array
flip chip) may be enclosed with a metallic cover. The metallic cover is
sealed to an outer frame, which in turn is sealed to metallization on the
top of the flip chip through a flexure, minimizing mechanical load
imparted to the flip chip. This forms a hermetic cavity enclosing the
die. This hermetic cavity is partially filled with an inert non
conductive fluid, which vaporizes when heated. Condensation occurs on the
inner surface of the metal cover where the heat may be conducted into the
outer frame for removal (e.g. rejection from the spacecraft).