A mask for photolithography and methods of manufacturing a mask and a semiconductor device are provided. The method of manufacturing a mask may comprise providing a substrate, forming a phase shift material layer on the substrate, forming a light blocking layer on the phase shift material layer, and forming a main pattern and a sub pattern on the substrate by patterning the phase shift material layer and the light blocking layer. The light blocking layer may be removed on the main pattern left on the light blocking layer remaining on the sub pattern. A semiconductor device may be manufactured using the mask to form a photoresist pattern on a semiconductor wafer. The pattern of the photoresist may be used to etch an object layer of the semiconductor wafer.