Provided is a method of manufacturing a display apparatus, the method including forming an amorphous silicon layer on a substrate; changing amorphous silicon in the amorphous silicon layer into crystalline silicon by irradiating the amorphous silicon with a laser beam emitted through a phase shift mask; and forming a display device, the phase shift mask including a base substrate; a barrier layer on the base substrate and including a plurality of transmissive portions which are spaced apart from each other in a first direction; and phase shift portions which alternately fill the plurality of transmissive portions in the first direction.