High performance heat sink for surface mount applications

Surface-mounted electronic module configurations are sensitive to thermal cycling because the reduced compliance between the component and module increases the thermally induced strain in the solder joint. Providing a thermal match between the component and the module reduces this strain, reduces low-cycle fatigue damage, and increases solder joint life. One way of achieving this thermal match is through the use of a thermally matched heat sink. In addition to having the required coefficient of thermal expansion (CTE), heat sinks for surface-mount avionic configurations require low weight and high thermal conductivity. A heat sink has been developed that has thermal conductivity close to aluminum, a CTE close to ceramic, and a weight density only 8% higher than aluminum. The flexural modulus of this heat sink is 40% higher than aluminum, which results in improved vibration performance. It is laminated, consisting of a thicker layer of graphite between thinner layers of copper-clad molybdenum,.<>