Influence of Package-Sink Interface Materials on Die Performance and Reliability

For high-power electronic packages, it is generally accepted that the package-sink interface materials used in the thermal solution influence hot-spot temperature(s) and junction-to-ambient thermal resistance. In this article we show how these package-exterior materials can noticeably influence across-die temperature gradients also. The numerical results reveal that the across-die thermal gradient can nearly double over a narrow range of conductivities typical of commercially available package-sink interface materials. Results show that the chip hot-spot temperature can be reduced 4 to 7 C by increasing the thermal interface material conductivity from 1 to 3 W/mk. This improvement can reduce the total thermal resistance from chip to ambient.