Accessible Chip Module
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
The cover of an accessible chip module has circular holes at every chip site which provide access to the EC pads of every chip and the chip itself. The holes are closed by a lid. The lid may be a piston that screws onto the upper surface of the chip for effective cooling. Two O-rings in the side wall of each hole provide a hermetic seal and adjust the torque to limit the pressure at which the piston pushes onto the chip. The piston-to-chip interface is electrically insulated by a thin polyimide layer which also absorbs any shock exerted on the lid (Fig. 1). The embodiment of Fig. 2 uses wire-bonded chips. Heat transfer does not occur from the chip itself but from studs located around the chip and supporting the piston.