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Liquid Cooled Module Assembly With Direct Chip Contact Heat Sinks Disclosure Number: IPCOM000126442D
Original Publication Date: 2005-Jul-18
Included in the Prior Art Database: 2005-Jul-18
Document File: 3 page(s) / 67K

Publishing Venue



A direct chip contact heat sink scheme for cooling chips on a multi-chip module is described. Individual heat sinks contact each chip with a solder joint between the base of each heat sink and the module cap. The upper finned portion of each heat sink is contained within a chamber formed by the cooling cap joined to the module cap. Heat is removed by a liquid cooling flowing over the fins within the chamber.

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Liquid Cooled Module Assembly With Direct Chip Contact Heat Sinks

A liquid cooled module assembly with direct chip contact heat sinks for the purpose of cooling high power electronic chips is disclosed. Small chip heat sinks are made to directly contact heat dissipating chips and extend through holes in a module cap into an upper chamber through which a cooling fluid passes. In this manner more direct heat flow paths are provided from the chip heat source to the coolant sink, eliminating virtually all thermal interface resistance components except the chip-to- heat sink interface. As shown in figure 1, the module cap is attached to the upper surface of the substrate. A hole is located in the module cap above each chip allowing a chip heat sink to be inserted through the hole to directly contact the chip upper surface. Each chip heat sink is comprised of an array of pins fins as shown in figures 1 and 2. These pin fins provide increased surface area to facilitate the transfer of heat to the liquid coolant. Of course it may be understood that other fin geometries (e.g. plate fins) can be used. A solder joint is formed around the base of each chip heat sink and the surrounding hole in the module cap to form a water-tight seal preventing the incursion of water into the chip spaces. The thermal contact region between each chip heat sink and chip may be a dry one as shown in figure 1. Alternatively, a fluid fill port (not shown) may be introduced in the side of the module cap. After soldering the chip heat sinks in place the free space within the module cap may be partially filled with a PAO (polyalphaolefin) oil to flood the surface contact discontinuities at the chip-to-heat sink contact interface and further reduce the contact thermal resistance. Still further, if required a very thin thermally conductive paste lay...