1 Department of Materials Science and Engineering, National Huwei Institute of Technology,
Yunlin 632, Taiwan
2 Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu,
Taiwan
3 Department of Material Science, Feng Chia University, Taichung 410, Taiwan
4 Institute of Materials Engineering, National Taiwan Ocean University, Keelung 202, Taiwan
| This work examines the thin-film properties and diffusion barrier behaviors of thin Ta-Co films, aiming at depositing highly crystallization-resistant and highly conductive diffusion barriers for Cu metallization. Structure analyzing indicates that the deposited Ta-Co films indeed have a glassy structure and are free from highly resistive intermetallic compounds, thus giving a low resisitivity under 20 µΩ -cm. Examining Si/Ta-Co/Cu stacked samples by using 4-point probes and XRD reveals that thermally induced failure of amorphous Ta-Co barriers are triggered by the barrier's crystallization at temperatures just under around 600 °C. The effectiveness of the nanostructure/amorphous Ta-Co thin film thus can be substantially enhanced by effectively blocking diffusion of copper towards the underlying silicon. |
full paper (pdf, 144 Kb)