Preparation of Cu 1− xTa x films and the material interaction in the Si/Cu 1− xTa x/Cu structure

Abstract

The present study investigated the microstructure of the Cu 1− x Ta x thin films and the material interaction in the Si/Cu 1− x Ta x /Cu structure. The Cu 1− x Ta x thin films were prepared by a multitarget DC magnetron sputtering deposition and the deposit composition was controlled by the power applied to Cu and Ta targets. It was tried to investigate the effect of Cu and Ta contents on the crystallinity, electrical property, and adhesive characteristic of Cu 1− x Ta x . The Cu 1− x Ta x film shows an amorphous structure when Ta content is 72 at.% and above. Amorphous Cu 1− x Ta x is a good adhesive layer for Cu interconnection. The addition of Cu content decreases the resistivities of sputtered amorphous Cu 1− x Ta x films. TaSi 2 and η″-Cu 3Si nucleated during the sputtering deposition of Cu 1− x Ta x on the Si wafer and long-period superstructure η″-Cu 3Si crystals grew with the annealing at 600 °C for 30 min. A mechanism for the formation of η″-Cu 3Si in the Si/Cu 1− x Ta x /Cu structure is described.