Behaviour of Copper In Annealed Cu/SiO(2)/Si Systems For On-Chip Interconnections

The electrical and structural properties of thin copper films attract increasing attention nowadays because of the use for on-chip interconnections. The main advantages of copper are the excellent conductivity and the relatively high stability against electro migration damaging. Interdiffusion at the copper/silicon interface can be a remarkable drawback of the interconnection quality even at room temperature which leads to the use of barrier layers between copper and silicon in technical applications. Often, thermal annealing of the as-deposited copper films is required to ensure proper process integration. In the present paper, Copper thin films of thickness 100 nm are deposited on SiO(2)/Si by ionized metal plasma deposition method. Then samples are annealed at different temperatures under high vacuum condition. The behavior of copper and the mechanism of compound formation studied at different temperatures, using scanning electron microscopy SEM, X-ray diffraction XRD and four point probe method. Diffusion of Cu into SiO(2)/Si layer start at 550'C and form Cu(x)Si(y). Oxidation of Cu is also take place at high temperature annealing.