an exposure method , exposure apparatus and mask are suitable for manufacturing an active matrix liquid crystal display including , for example , a gate electrode layer and a source / drain electrode layer . a stitching portion between unit patterns in a second layer is offset from the stitching portion in a first layer by a predetermined distance . the stitching portions of the second layer are always positioned over unit patterns of the first layer . accordingly , the contrast gap that occurs at the stitching portion as a boundary is defined only by an error in the exposure position of the second layer . the contrast gap is not affected by an error in the exposure position of the first layer , unlike the conventional method . because the contrast gap caused by the error in the exposure position of the first layer is eliminated , the total contrast gap that occurs at the stitching portion as a boundary is significantly reduced .