Structure and stress of Cu films prepared by high power pulsed magnetron sputtering

Owing to its high ionization degree, high power pulsed magnetron sputtering (HPPMS) has proven advantageous for Cu film growth. In this study, Cu films with different thicknesses deposited by HPPMS at different peak powers were prepared. Moreover, a titanium (Ti) interlayer was used to improve the Cu (111) out-of-plane preferred orientation and adhesion. The films prepared at high peak power exhibited high tensile stress, large grain size, and low electrical resistivity. Thicker Cu films exhibited lower stress and larger grain size, resulting in better electrical conductivity and adhesion. At the same time, a Ti interlayer with (002) preferred orientation could greatly improve the (111) out-of-plane preferred orientation and adhesion of the Cu film.