A method of photolithography including coupling a first aperture to a lithography system, then performing a first illumination process to form a first pattern on a layer of a substrate using the first aperture, thereafter coupling a second aperture to the lithography system, and performing a second illumination process to form a second pattern on the layer of the substrate using the second aperture. The first aperture includes a first pair and a second pair of radiation-transmitting regions. The second aperture includes a second plate having a third pair and a fourth pair of radiation-transmitting regions.