Westman, Champlin & Kelly, P.A.
Method for etching Mo-based metal gate stack with aluminium nitride barrier
The present application discloses a method for etching a Mo-based metal gate stack with an aluminum nitride barrier, comprising the steps of forming a SiO2 interface layer, a high K dielectric layer, a Mo-based metal gate layer, an AlN barrier layer, a silicon gate layer and a hard mask in sequence on a semiconductor substrate; performing lithography on the semiconductor substrate with the SiO2 interface layer, the high K dielectric layer, the Mo-based metal gate layer, the AlN barrier layer, the silicon gate layer and the hard mask using a photoresist, and etching the hard mask; removing the photoresist, and performing an anisotropic etching for silicon gate with high selectivity to the underlying AlN barrier layer and metal gate by dry etching using the hard mask; performing an anisotropic etching for the AlN barrier layer, the Mo-based metal gate layer, and the high K dielectric layer by a dry etching. With the present method for etching a Mo-based metal gate stack with an aluminum nitride barrier, a vertical etching profile will be obtained and a silicon substrate has little loss, which facilities a high K dielectric/metal gate stack integration.
Institute of Microelectronics, Chinese Academy of Sciences
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Qiuxia Yongliang
Xu Li