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High-Density, High-Thermal Dissipation Substrates Fabricated Using a Conductive Composite Material

Published online by Cambridge University Press:  10 February 2011

Lutz Brandt ,
Goran Matijasevic ,
Pradeep Gandhi  and
Catherine Gallagher
Lutz Brandt
Affiliation:
Ormet Corporation, 2236 Rutherford Road, Suite 109, Carlsbad, CA 92008, ormet@pacbell.net
Goran Matijasevic
Affiliation:
Ormet Corporation, 2236 Rutherford Road, Suite 109, Carlsbad, CA 92008, ormet@pacbell.net
Pradeep Gandhi
Affiliation:
Ormet Corporation, 2236 Rutherford Road, Suite 109, Carlsbad, CA 92008, ormet@pacbell.net
Catherine Gallagher
Affiliation:
Ormet Corporation, 2236 Rutherford Road, Suite 109, Carlsbad, CA 92008, ormet@pacbell.net
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Abstract

Thermal performance of conventional printed circuit materials can be increased with the use of heat sinks. Even better thermal dissipation can be achieved with the use of insulated metal boards as substrates. However, this technology is limited in the number of circuit layers and the circuit density. A novel material based on transient liquid phase sintering (TLPS) was developed and used to make additive multilayer circuits on metal substrates. The partial sintering operation of the polymer-based conductive composite is akin to that of Cermet materials, but processing is at temperatures of < 250° C. A metallurgically alloyed web is formed by TLPS, providing good conductivity and stability with respect to humidity and heat exposure. An interpenetrating polymer network provides adhesion to a variety of substrates.

Photoimageable dielectrics have been used to image circuit traces (as fine as 50 μm) and vias (down to 75 μm). The conductive composite is filled into the grooves and cured to form circuits. Sequential building of circuit and via layers yields the desired planarized circuit with blind and buried solid vias throughout the multilayer structure. Metal substrates have been chosen to achieve high thermal dissipation. The thermal conductivity of the polymer-based conductive composite itself was measured to be 25 W/mK, comparable to that of solder materials. Thermally resistive adhesive interfaces have been minimized in the fabricating the structure, resulting in a high thermal dissipation, as well as high density substrate.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 515: Symposium J – Electronic Packaging Materials Science X , 1998 , 131
Copyright
Copyright © Materials Research Society 1998

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References

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