A method of manufacturing a semiconductor device is provided. The method includes forming a molding layer and a supporter layer on a semiconductor substrate, forming a multiple mask layer including a first mask layer and a second mask layer formed on the first mask layer, on the supporter layer. The first mask layer is formed of a material having an etch selectivity with respect to the molding layer and the second mask layer is formed of a material having an etch selectivity with respect to the supporter layer. The method includes forming a first mask pattern and a second mask pattern formed on the first mask pattern by patterning the multiple mask layer, etching the supporter layer by performing a first etching process using the second mask pattern as an etch mask, etching the molding layer, and forming a hole by performing a second etching process using the first mask pattern as an etch mask.