The present study investigated the microstructure of the Cu1-xTax thin films and the material interaction in the Si/Cu1-xTax/Cu structure. The Cu1-xTax 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 Cu1-xTax. The Cu1-xTax film shows an amorphous structure when Ta content is 72 at.% and above. Amorphous Cu1-xTax is a good adhesive layer for Cu interconnection. The addition of Cu content decreases the resistivities of sputtered amorphous Cu1-xTax films. TaSi2 and eta"-Cu3Si nucleated during the sputtering deposition of Cu1-xTax on the Si wafer and long-period superstructure eta"-Cu3Si crystals grew with the annealing at 600degreesC for 30min. A mechanism for the formation Of eta"-Cu3Si in the Si/Cu1-xTax/Cu structure is described. (C) 2003 Elsevier Science B.V. All rights reserved.