Diffusion barrier capability of Zr–Si films for copper metallization with different substrate bias voltage

Abstract

Efficiency of Zr–Si diffusion barriers in Cu metallization has been investigated. Amorphous Zr–Si diffusion barriers were deposited on the Si substrates by reactive magnetron sputtering with different negative substrate bias. The mass density of Zr–Si films increases with substrate bias voltage up to − 150 V. The deposition rate decreased with the negative substrate bias from 5.4 nm/min to 1.8 nm/min. XRD measurements show that the Zr–Si barriers have amorphous structure in the as-deposited state. The FE-SEM images show that the sizes of spherical granules on the Zr–Si film surface increase with increasing the substrate bias. The Cu/Zr–Si/Si structures were prepared and annealed in Ar ambient at temperatures varying from 500 to 650 °C for an hour. It is shown from the comparison study that the Zr–Si film deposited with − 150 V is better at maintaining good performance in Cu/Zr–Si/Si contact system than that of Zr–Si film deposited with − 50 V.