Circuit module with convection cooling by a coolant flowing between a heat producing component and the face of a piston.

摘要

In an improved circuit module (9) with a flat chip-carrying substrate (10) and cylindrical pistons (19) that contact the chips (12) for cooling, each piston has an axial bore (38) that carries a dielectric liquid to the chip and the lower face (23) of the piston (facing the chip) is spaced away (22) from the chip to establish radial channels that carry the liquid across the surface (14) of the chip. The face of the piston, as seen in a section through the axis, is shaped to provide a selected flow pattern across the surface of the chip. The piston face reduces the channel height in the direction of flow where the liquid is non-boiling and thereby offsets the tendency for the flow rate to decrease as the circumferential width of the channel widens. The piston face increases the channel height in the direction of flow where the liquid is boiling to handle the increase in volume caused by the vapor. In one embodiment, the piston carries a shroud (70) around the chip which causes the coolant to flow across the edge (71) of the chip to provide additional chip cooling and to impinge on the nearby region of the substrate that supports the chips to remove heat that flows from the chip to the substrate. In one embodiment, the pistons are thermally conductive, and the temperature of the coolant at the inlet to the pistons is lower than the temperature required at the outlet to cool the piston. The pistons have fins that help to condense the vapor. In this embodiment, the lower face of a piston has radial fins that establish pie-shaped channels for the coolant to flow in. The fins (36) also provide heat transfer by conduction from the chip to the piston supporting structure (the "hat") (17).