CPC H01L 21/3088 (2013.01) [C23C 16/401 (2013.01); C23C 16/45525 (2013.01); C23C 16/56 (2013.01); H01L 21/3065 (2013.01); H01L 21/3081 (2013.01); H01L 21/3085 (2013.01); H01L 21/3086 (2013.01); H10B 12/0335 (2023.02); H10B 12/053 (2023.02); H10B 12/315 (2023.02); H10B 12/34 (2023.02); H10B 12/482 (2023.02)] | 15 Claims |
1. A method of forming active patterns, the method comprising:
forming a line structure on a substrate, the line structure extending in a first direction parallel to an upper surface of the substrate;
forming a sacrificial layer on the substrate to cover the line structure;
sequentially forming a first mask layer and a photoresist pattern on the sacrificial layer, the first mask layer including silicon oxynitride and the photoresist pattern including a first opening exposing an upper surface of the first mask layer;
etching the first mask layer by an etching process using the photoresist pattern as an etching mask to form a first mask having a second opening exposing an upper surface of the sacrificial layer, the etching process using a first etching gas including SF6 gas and CHF3 gas so that carbon-sulfur (C—S) bonds are formed on a surface of the photoresist pattern to restrain etching of the photoresist pattern, and a slope of the second opening having an angle equal to or greater than 80 degrees with respect to the upper surface of the substrate;
partially etching the sacrificial layer using the first mask as an etching mask to form a third opening exposing a portion of the line structure;
removing the portion of the line structure exposed by the third opening to divide the line structure into a plurality of pieces spaced apart from each other in the first direction; and
etching an upper portion of the substrate using the plurality of line structures as an etching mask to form a plurality of active patterns spaced apart from each other in the first direction.
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