1. Integrated Circuit Advanced Process R&D Center, Institute of Microelectronics of Chinese Academy of Sciences (IMECAS) , Beijing 100029 , China
2. State key Lab of Fabrication Technologies for Integrated Circuits, Institute of Microelectronics of Chinese Academy of Sciences , Beijing 100029 , China
3. School of Integrated Circuits, University of Chinese Academy of Sciences , Beijing 100049 , China