INTERDIFFUSIONS AND REACTIONS IN CU TIN/TI/SI AND CU/TIN/TI/SIO2/SI MULTILAYER STRUCTURES/

Sputtered TiN (30-120 nm thick)/Ti (30 nm thick) films were studied as a diffusion barrier between silicon substrate and copper films. The e ffects of TiN thickness and the existence of a SiO2 layer between Ti a nd silicon substrate on the diffusion barrier property were investigat ed using various characterization methods. The copper diffusion barrie r property of TiN/Ti was found to be affected not only by the TiN thic kness, that is diffusion distance, but also by the microstructure of t he TiN, which changes with the thickness of TIN film. The existence of the SiO2 layer enhanced the diffusion barrier property of TiN/Ti. Thi s is because the SiO2 layer between Ti and Si inhibited the formation of titanium silicides, so the Ti layer was available to be used as the sacrificial diffusion barrier for copper.