A method of forming a semiconductor device can include determining a shot set including a plurality of shots, based on a final pattern used to form a mask. Shots included in the plurality shots can be classified as being in a first pass shot set or in a second pass shot set, where each can include a plurality of non-directly neighboring shots. A first pass exposure can be performed to radiate a reticle to provide the first pass shot set and a second pass exposure can be performed to radiate the reticle to provide the second pass shot set.