Using OES to Predict Nitrogen Concentration for Plasma Nitrided Gate Oxide Process and Applications

• Main Authors: Hsueh-Hsiu Yang, 楊學修
• Other Authors: Chia-Fu Chen
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/12481570868588281895

碩士 === 國立交通大學 === 工學院碩士在職專班半導體材料與製程設備組 === 95 === Due to the driving force of the manufacturing cost and device performance in the semiconductor industry, the transistor density has been continuously doubled in every year. Consequentially the transistor is also constantly down scaling. Therefore, looking for the material of gate dielectric with high dielectric constant (high k) to reduce the leak current and metal gate to decrease the effective oxide thickness (EOT) for high performance transistor are always the priority for semiconductor industry. Oxynitride is popularly used as gate dielectric in complementary metal oxide semiconductor (CMOS) process for device scaling before high K and metal gate being commercialized in semiconductor industry. One of the important technics to grow oxynitride is decoupled plasma Nitridation (DPN). For DPN process, the most important process parameter is the concentration of nitrogen in SiO2. However two major issues are introduced by cluster. One is that once the nitrogen concentration is out of expectation there is no way to decouple which chamber is the root cause. In other words, there is no in-situ monitoring techanic in place for DPN process. The other is that currently technic used to quantify nitrogen concentration is to use re-oxidation. However re-oxidation is more complicate and not cost effective. In this thesis, 5 band pass filters with different wave length are used to detect the spectrum intensity of species in DPN chamber. 5 of them are 337.03 nm、357.38 nm、391.28 nm、590.43 nm and 601.31 nm respectively. Thereafter the intensity of optical emission spectroscopy (OES) is used to correlate the Nitrogen concentration that measured by XPS. The results successfully demonstrate that the specific wavelength of 337.03 nm in the spectrum has the highest sensitivity and the best correlation to nitrogen concentration. Therefore it is also believed that the nitrogen concentration is dominated by this specific species. Furthermore, the result is extended and applied for optimization of the device performance from OES intensity. Results turning out show that some electrical properties of device correlate to OES intensity including equivalent oxide thickness, saturated drain current and threshold voltage. In other words, OES could be used to optimize device performance qualitatively. Finally this is an in-situ and simple methodology.