Metallurgy and performance of electrodeposited copper for flexible circuits

In this paper, we consider intrinsic properties of copper electrodeposited as plateup on polyimide substrate, thermal response of electrodeposited copper and fatigue performance of copper and copper/polyimide construction. The critical material characteristics examined are grain morphology and structure, crystallographic texture, microhardness, uniaxial strength and ductility and isothermal cyclic fatigue life. Given optimum processing conditions, copper plateup in flexible circuits displays fine grain structure, high ductility, adequate thermal stability, freedom from thermal embrittlement and excellent fatigue endurance over a wide range of strain amplitudes.