Measurement of Biaxial Stress Using Electrodeposited Copper Foil with a Microcircular Hole : Method Using the Probability of the Occurrence of Slip

The dependence of slip band occurrence at the periphery of microcircular holes formed by photoetching in electrodeposited copper foil upon the number of cycles and cyclic stress magnitude for plane bending and cyclic torsion is examined. The results show that the principal stresses in an element under biaxial stresses, which are undetectable by the conventional copper electroplating method, can be evaluated using an equation based on the probability of slip occurrence, which takes into account both cyclic stress magnitude and the number of cycles.