An exemplary method for modifying at least part of an integrated circuit layout comprises obtaining an integrated circuit device layout, the integrated circuit device being designed using a library of cells, obtaining a modified library of cells, and replacing at least one cell in the integrated circuit device layout with a corresponding modified cell of the modified library to obtain a modified integrated circuit device layout. The modified library includes modified cells corresponding to cells in the library and candidate areas of each modified cell indicating portions of the cell for further processing. At least some of the modified cells have been modified to at least partially compensate for a manufacturing effect.