Barrier Properties of TaNx and TaSixNy for Cu Metallization

• Main Authors: Chi-chang Wu, 吳其昌
• Other Authors: Wen Luh Yang
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/84319590936903201801

碩士 === 逢甲大學 === 電機工程學系 === 88 === This thesis studies the barrier properties of TaNx and TaSixNy films for Cu metallization. First, the characteristics of the TaNx films deposited by reactively sputtering with various nitrogen flow ratios were investigated. It is found that the phase of TaNx films transformed from a-Ta、b-Ta(-N)、Ta2N and TaN respectively with increasing the nitrogen flow ratio. For the thermal stability of TaNx as barrier layers against Cu diffusion, the Cu/pure Ta/n+-p junction diodes remained stable at temperature up to 400oC, and suffered severe degradation after 500oC anneal. For the Cu/TaN(5%)/n+-p diodes, the junction characteristics remained stable at temperature up to 500oC. In addition, it is found that junction leakage current was increased with increasing the nitrogen flow ratio. From the results of material analysis, the author conjectured that the stress of TaNx thin film and its surface roughness might be the factor that affected the barrier capabilities. Second, the barrier capability of TaNx after various plasma treatments to against Cu diffusion were also investigated. It is found that the barrier capabilities were improved after either N2, NH3 or N2O plasma treatments, and was more significant improvement with more treating time. On the other hand, the ideality factor values of the diodes were slight increased after plasma treatment. Finally, the barrier capabilities of TaSixNy films deposited by reactive-sputtered Ta5Si3 target with various nitrogen flow ratios were investigated. The better barrier capability was found for the film at a nitrogen flow ratio of 15%.