Adequate mechanical characterization of PCB copper traces for 2nd level FEM simulations

The paper describes an experimental approach to determine mechanical properties of copper that have been used in technical application, e.g. PCB copper traces. The investigations focus on an experimental design to determine the mechanical behavior of real PCB copper traces. In the first step the differences between idealized specimen and representative specimens for real PCB copper traces will be discussed. Starting out from these considerations of representative specimens, the design of the test setup will be described. Substantial design ideas considered not only the specimen, but also loading conditions that represent realistic stress situations. Experiments were also conducted on specimens made from rolled copper sheets, which are used to manufacture flexible PCBs, and from copper ribbon material, which is used for interconnectors of photovoltaic modules. The differences between the samples show the range of mechanical behavior of copper depending on its preprocessing. The copper sheets for the PCB production were structurally analyzed, by the preparation of cross sections and surface roughness measurements. The results of these analyses explain why mechanical experiments on real PCB copper need special consideration.