Electrical-thermal characterization of wires in packages

The electrical-thermal co-simulation approaches, for wires-in-air and wires-in-package, are developed by the coupling between their electrical and thermal properties, using ADS (Agilent Design System) Symbolically-Defined Devices (SDD) models for multiple wire segments. Key parameters for these simulation models are then derived from experimental results. These experimentally validated (or assisted) simulation models can be used to predict electrical-thermal behavior of bond wires in situations of interest, and to develop design guidelines for reliable operation. Test boards with wires-in-air were made, and fusing currents on wires of different materials (Au, Cu, Ag), lengths, and diameters were measured and compared with published data. Some QFN package testers having wires in different materials(Au, Cu, Ag), lengths, and different diameters, with mold material were also made to characterize the wires in real package environment. Simulation and experiment data, as well as some failure-analysis (FA) data through X-ray and SEM methods, are presented in the paper.