摘要 |
A method of lithography patterning includes forming a first etch stop layer, a second etch stop layer, and a hard mask layer on a material layer. The materials of the first etch stop layer and the second etch stop layer are selected by the way that there is a material gradient composition between the second etch stop layer, the first etch stop layer, and the material layer. Hence, gradient etching rates between the second etch stop layer, the first etch stop layer, and the material layer are achieved in an etching process to form etched patterns with smooth and/or vertical sidewalls within the second and the first etch stop layers and the material layer. |