a photolithography system has at least one spatial light modulator , a scanning mechanism configured to move an exposure area relative to a target object in a scanning direction , a plurality of memories , a data processor , and exposure controller . the exposure area is defined as a projection area of the spatial light modulator . the plurality of memories corresponds to a plurality of partial exposure areas that is defined by dividing the exposure area . the data processor successively writes exposure data into each memory in accordance with the timing of an exposure , and the exposure controller controls the plurality of light modulating elements on the basis of the relative position of the exposure area . the data processor writes newly generated exposure data into the first memory , and shifts exposure data stored in the 1 st to st memories to the 2 nd to n th memories , respectively .