Mechanical Properties of Copper Thin Films Used in Electronic Devices

Abstract

Abstract This paper presents tensile and low cycle fatigue properties of copper thin films used in electronic devices. Copper films tested were rolled copper, electrolytic copper, direct current plated copper and pulse plated copper films. Tensile tests and strain controlled 4-point bending low cycle fatigue tests were carried out and cycles to crack initiation and those for propagation were obtained. The direct current plated copper showed the largest Young's modulus among the copper films. The electronic copper showed the largest yield stress and ultimate tensile strength, and the pulse plated copper the largest elongation. The strongest resistance to crack initiation was found in the rolled copper but there was no large difference in the cracking resistance among the other copper films. Cracks of the direct current and pulse plated coppers propagated faster than those of the other copper films.