Abstract
Fatigue strength of electroplated copper thin films was measured under uni-axial stress loading. Two kinds of electroplated films were prepared for the fatigue test. One was a commercial film mainly used for interconnections in printed wiring boards. The other film was grown on a stainless steel substrate by using acid copper sulfate bath without any additive agent. The fatigue fractured surfaces were observed by using SEM (scanning electro microscope). It was found that the fracture mode of the films was quite different with each other. The former film showed a ductile fracture surface, while the latter film showed brittle one. In addition, the fatigue strength of the latter was about 1.5 times higher than that of the former. This was mainly due to the difference of the micro texture between the two films.
