1. A method of patterning a substrate, the method comprising forming a first layer of photoresist on a stack of materials on the substrate, wherein the stack of materials comprises a blanket top mask layer over a blanket etch stop layer over an anti-reflective coating over a target etch layer; patterning the first layer of photoresist to form a first pattern; etching the first pattern into the blanket top mask layer to form a first patterned top mask layer; removing any remaining material from the first layer of photoresist; forming a second layer of photoresist on the first patterned top mask layer; patterning the second layer of photoresist to form a second pattern; etching the second pattern into the first patterned top mask layer to form a second patterned top mask layer; and etching the first pattern and the second pattern into the stack of materials, wherein the first pattern and the second pattern are formed in the stack of materials during the same etching operations.