Thermal analysis and measurement of plastic packaged GaAs devices

Three dimensional thermal analyses of a GaAs device in a plastic SOIC package mounted on a printed circuit board are reported. Finite element technique is utilized to analyze the complete structure including the chip, the package and the board. Unit thermal profile method is used to refine the chip level analysis by considering individual heat sources and the die-attach layer. Temperature dependence of GaAs thermal conductivity is taken into account in the analyses. The analysis procedure demonstrates the advantages of both methods. Thermal measurements using liquid crystal microthermography are carried out to validate the modeling results.