High-density electronic package employs electroplated copper foils for micro wiring. To ensure the reliability of the micro wiring technique, the characteristics of deformation of electroplated copper foils must be clarified. Therefore, tensile tests using electroplated copper foils have been conducted by many researchers, and some of them reported that the stress-strain relations show the time dependency at room temperature. Since the strain in the time-dependent stress-strain relation contains the creep strain, the characteristics of the creep deformation of electroplated copper foils should be investigated in detail to clarify its deformation mechanism. In this study, the creep tests using an electroplated copper foil were conducted to construct the creep constitutive model. The tensile tests under several strain rates and the stress relaxation tests by maintaining strain at several values were also conducted, and the mechanism of the deformations in these tests were discussed by using the constructed creep model.
