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Cooling Cap for Powder or Liquid filled Modules

IP.com Disclosure Number: IPCOM000084223D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Antippas, SP: AUTHOR

Abstract

The rate of heat transfer from the devices of a module to the substrate is inadequate in many applications. Consequently, additional cooling for the devices is provided by the conduction and/or convection of heat from the devices to the cap of the module through a liquid. The cap is cooled by a stream of air or water. In some cases the liquid is intended to boil under normal operating conditions for reasons of improved cooling efficiency. There are problems associated with the use of liquid coolants under the cap of a module.

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Cooling Cap for Powder or Liquid filled Modules

The rate of heat transfer from the devices of a module to the substrate is inadequate in many applications. Consequently, additional cooling for the devices is provided by the conduction and/or convection of heat from the devices to the cap of the module through a liquid. The cap is cooled by a stream of air or water. In some cases the liquid is intended to boil under normal operating conditions for reasons of improved cooling efficiency. There are problems associated with the use of liquid coolants under the cap of a module.

The method of cooling shown in Figs. 1 and 2 eliminates cooling problems by the substitution of the liquid inside the cap with a thermally conductive power and the use of a cap 10.

The module is filled with a thermally conductive powder 12, such as alumina or beryllia. The powder conducts heat from the devices 14 of the substrate 16 to the cap 10, which is cooled by a stream of air or liquid.

The distance from each device 14 of the module to the cap 10 has to be small for an adequately high rate of heat transfer. For instance, a desirable clearance between the devices 14 of a 50 x 50 mm. module and the cap 10 may be in the neighborhood of 0.50-0.75 mm. For this reason the module cannot be filled completely with powder. There may be voids which inhibit the transfer of heat. This problem is resolved by the use of caps providing adequate clearance to the devices.

Studs 18 soldered to the cap 10 directly over the devices 14 extend inside the cap and reach within a short distance of the devices, as shown. The diameter of each stud 18 is nearly equal to the dimensions of a device 14 and considerably smaller than the dimensions of the module. Hence the small gap between a device 14 and the nearest stud 18 is filled with relative ease.

A shallow taper at the inner extremities of the studs 18 inside the cap 10 of the module facilitates further, the penetration of powder 12 in the above gap. The extremities of the studs 18 extending outside th...