Browse Prior Art Database

Design of a High Power Dissipation Module

IP.com Disclosure Number: IPCOM000052163D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Doo, VY: AUTHOR

Abstract

The module combines the back face chip mounting and the solder reflow input/output (I/O) joints at minimum stress in the solder joints. The figure shows the vertical section of the module. The silicon chip 2 is rigidly mounted by joint 1 onto a module case 3 which has cooling fins 4 for efficient power dissipation. The chip I/O pins 5 are connected to a fanout plate 6 by solder joints 7. A cover plate 8, which has brazed I/O pins 5 and flexible contact wires 9 attaching to the pins 5, is soldered to the module case 3 to seal, at 10, the chip and fanout plate 6 in the module case 3.

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Design of a High Power Dissipation Module

The module combines the back face chip mounting and the solder reflow input/output (I/O) joints at minimum stress in the solder joints. The figure shows the vertical section of the module. The silicon chip 2 is rigidly mounted by joint 1 onto a module case 3 which has cooling fins 4 for efficient power dissipation. The chip I/O pins 5 are connected to a fanout plate 6 by solder joints 7. A cover plate 8, which has brazed I/O pins 5 and flexible contact wires 9 attaching to the pins 5, is soldered to the module case 3 to seal, at 10, the chip and fanout plate 6 in the module case 3. The contact pads 7 on the fanout plate 6 may have a melting point slightly below the soldering temperature for the seal at 10, between the cover plate 8 and the module case 3, such that the flexible contact wires 9 can push into the molten contact pads 7 during the cover plate seal. This gives positive contact. The flexible contacts 9 minimize the stress in solder reflow joints 12 during subsequent thermal cycling.

The contact pad pitch is the same as the I/O pin pitch, about 0.070 inch presently. Thus, the pad 7 can be 0.030-0.050 inch diameter such that there will be little problem in having the flexible wires 9 make contact with their respective pads.

The power dissipation capacity depends upon the material of the module case 3, the shape and geometry of the case, the chip size, and the external cooling media and speed. The cooling fins 4 ca...