Substrate, method of exposing a substrate, machine readable medium

A double exposure method for enhancing the image resolution in a lithographic system, is presented herein. The invention comprises decomposing a desired pattern to be printed on the substrate into at least two constituent sub-patterns that are capable of being optically resolved by the lithographic system, coating the substrate with a first positive tone resist layer and a thin second positive tone resist layer on top of a target layer which is to be patterned with the desired dense line pattern. The second resist material is absorbing exposure radiation during a first patterning exposure and after development during a second patterning exposure to prevent exposure above energy-to-clear of at least a portion of the first resist material underneath exposed portions of the second resist material layer.