| CPC H01L 21/0337 (2013.01) [H01L 21/0276 (2013.01); H01L 21/0332 (2013.01); H01L 21/3065 (2013.01); H01L 21/3086 (2013.01); H01L 21/31116 (2013.01); H01L 21/31144 (2013.01); H01L 21/32136 (2013.01); H01L 21/32139 (2013.01)] | 20 Claims |

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1. A method of forming a semiconductor device, the method comprising:
providing a substrate on which a layer is formed;
forming a lower hard-mask layer on the layer, the lower hard-mask layer comprising silicon;
forming an upper hard-mask pattern on the lower hard-mask layer, the upper hard-mask pattern comprising oxide;
forming a lower hard-mask pattern by etching the lower hard-mask layer using the upper hard-mask pattern as an etch mask and using an etching gas that comprises a first gas comprising a metal-chloride and a second gas comprising nitrogen; and
forming a plurality of contact holes in the layer by etching the layer using the lower hard-mask pattern as an etch mask.
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