Disclosed are semiconductor device fabricating method and semiconductor device fabricated by the same. The method includes forming on a lower mask layer first upper mask patterns and sacrificial spacers that cover sidewalls of the first upper mask patterns, forming first holes in the lower mask layer below the first upper mask patterns, forming second holes in the lower mask layer not covered by the first upper mask patterns and the sacrificial spacers, forming second upper mask patterns filling a space between the sacrificial spacers on the lower mask layer and also forming sacrificial patterns filling the first and second holes, removing the sacrificial spacers, using the first and second upper mask patterns to etch the lower mask layer, and removing the sacrificial patterns.