The fabrication and dry etching of poly-Si/TaN/Mo gate stack in the metal inserted poly-Si stack structure |
| |
Authors: | Yongliang Li Qiuxia Xu |
| |
Affiliation: | Integrated Circuit Advanced Process Center, Institute of Microelectronics, Chinese Academy of Science, Beijing 100029, China |
| |
Abstract: | The Mo-based metal inserted poly-Si stack (MIPS) structure is an appropriate choice for metal gate and high-k integration in sub-45 nm gate-first CMOS device. A novel metal nitride layer of TaN or AlN with high thermal stability has been introduced between Mo and poly-Si as a barrier material to avoid any reaction of Mo during poly-Si deposition. After Mo-based MIPS structure is successfully prepared, dry etching of poly-Si/TaN/Mo gate stack is studied in detail. The three-step plasma etching using the Cl2/HBr chemistry without soft landing step has been developed to attain a vertical poly-Si profile and a reliable etch-stop on the TaN/Mo metal gate. For the etching of TaN/Mo gate stack, two methods using BCl3/Cl2/O2/Ar plasma are presented to get both vertical profile and smooth etched surface, and they are critical to get high selectivity to high-k dielectric and Si substrate. In addition, adding a little SF6 to the BCl3/O2/Ar plasma under the optimized conditions is also found to be effective to smoothly etch the TaN/Mo gate stack with vertical profile. |
| |
Keywords: | Mo TaN Metal gate stack MIPS Plasma etching |
本文献已被 ScienceDirect 等数据库收录! |
|