Abstract
The thermal stability of Cu interconnections with tungsten nitride (WN x ) diffusion barriers deposited at various nitrogen flow ratios was analyzed. The thermal stability and barrier performance of the WN x films were improved using N 2 O plasma treatment. The sheet resistance of the Cu/N 2 O plasma treated WN x /Si was found to be stable even after annealing at 750°C for 30 minutes. It was observed using transmission electron microscopy and x-ray photoemission spectroscopy that the nitridation and oxidation of the WN x barrier occurs and an amorphous layer is formed after N 2 O plasma treatment.