Plasma Effect on Liquid-Phase Deposited Insulator

• Main Authors: Yu-Jie Shiau, 蕭宇傑
• Other Authors: Ching-Fa Yeh
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/58626910761080000884

碩士 === 國立交通大學 === 電子工程系 === 89 === To reduce the probability of moisture uptake and to strength the adhesion between MSQ/liner-LPD and copper, the improvement of liner LPD-SiO2 deposited on MSQ is studied. In this work, to make LPD-SiO2 deposited on MSQ film, we adopted H2 plasma treatment on MSQ. In addition, H2 plasma treatment can improve MSQ leakage current but dielectric constant invariant. Although LPD deposition after H2 plasma can make leakage current slightly increase, however the increase can be reduced if the time of plasma treatment is long enough. Besides, LPD-SiO2 incubation time also increases as H2 plasma treatment time increases. However the deposition rate is almost independent of plasma treatment. We have proposed a model to explain the phenomenon about incubation time according to the results of SIMS spectra and LPD deposition-rate graph. Conclusively, 10min H2 plasma is the best condition in this work. To further improve the performance of LPD-SiO2 with N2O plasma, at the first time, we investigated two-steps N2O plasma. From the C-V curves, we obviously found that the flat-band voltage of these samples shifts to either left or right. And we have tried to introduce two mechanisms about the flat-band voltage shift. However, the amount of left-shift for the first mechanism is larger than that of right-shift for the second. From the leakage current (J-E) curves, we found the better improvement of LPD-SiO2 with two-steps N2O plasma. Nitrogen incorporation at Si/LPD-SiO2 interface and reoxidation reaction can make leakage current decrease. As the thickness of LPD-SiO2 in the first-step N2O plasma decreases, the leakage current density obviously decreases. In addition, to deposit high quality LPD oxide film, we adopted new SiO2 powder & new H2SiF6 liquids with less impurity. Under the condition of new H2SiF6 liquids, the leakage current density of LPD-SiO2 prepared with new SiO2 powder at E=2MV/cm is 2x10-9 A/cm2, and approximately two orders lower than that with old SiO2 powder. The breakdown field is also slightly high. The uniformity of deposition thickness is about ~2%, and the dielectric constant value is ~3.3.