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Integral Heatsink Printed Circuit Card

IP.com Disclosure Number: IPCOM000050847D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Aakalu, NG: AUTHOR [+2]

Abstract

This card structure is made from a flexible printer circuit (PC) subassembly laminated to a suitable metal heatsink with a pressure-sensitive adhesive sheet. Personalization of the copper sheet which forms the top layer of the flexible subassembly can be made before or after bonding to the metal heatsink plate. A solder mask will then be applied on top of the circuit. The solder mask is for both environment protection and to act as solder dam in the subsequent solder reflow operation.

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Integral Heatsink Printed Circuit Card

This card structure is made from a flexible printer circuit (PC) subassembly laminated to a suitable metal heatsink with a pressure-sensitive adhesive sheet. Personalization of the copper sheet which forms the top layer of the flexible subassembly can be made before or after bonding to the metal heatsink plate. A solder mask will then be applied on top of the circuit. The solder mask is for both environment protection and to act as solder dam in the subsequent solder reflow operation.

The drawing shows an exploded cross section of the final assembly. The flexible PC sheet 1 is laminated to the heatsink 3 using a pressure-sensitive adhesive sheet 2. The heatsink 3 material can be steel, aluminum, etc. The flexible PC sheet 1 is three layers in construction. Thermoset polyimide 4, adhesive 5 and copper foil 6 are bonded together prior to attachment to the heatsink plate 2. To personalize after lamination, it may be necessary to coat the backside of the heatsink with etch resist 7 to protect both the heatsink and the etch bath. The solder mask 8 is screen-printed and cured after the lamination process.

The heatsink 3 also provides mechanical rigidity to the electronic circuit. However, it can be flexible enough to allow the use of a roll to roll process for the lamination step in manufacturing the final subassembly.

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