Heat sink mechanism hydraulically propelled into contact with semiconductor devices

In an apparatus for simultaneously cooling a plurality of planar semiconductor devices, a common chamber containing a pressurized hydraulically compressible medium and having a plurality of aligned first openings in a bounary wall thereof, a plurality of parallel elongated rods individually extending outwardly from and slidably mounted within the respective first openings, the inner ends of the rods being in direct fluid pressure communication with the compressible medium, a plurality of heat sinks individually associated with the rods and having first and second opposed surfaces, the first surfaces of the heat sinks being engageable with corresponding surfaces of the respective semiconductive devices, means for individually and rigidly coupling the outer end of each rod to the second surface of the associated heat sink so that each resulting rod-heat sink assembly constitutes a rigid piston acted upon with the same pressure by the compressible medium, and means coupled to the interior of the chamber for varying the hydraulic pressure of the compressible medium within the chamber.