The present inventive concepts provide methods for fabricating semiconductor devices. The method may comprise providing a substrate, stacking a conductive layer and a lower mask layer on the substrate, forming a plurality of hardmask layers each having an island shape on the lower mask layer, forming a plurality of upper mask patterns having island shapes arranged to expose portions of the lower mask layer, etching the exposed portions of the lower mask layer to expose portions of the conductive layer, and etching the exposed portions of the conductive layer to form a plurality of contact holes each exposing a portion of the substrate.