A method of laying out features for alternating aperture phase shift masks. The method includes defining features on a grid of a uniform basic pitch, orienting the features such that those of the features defined, at least in part, by phase shifting shapes are oriented along a primary direction, and spacing two features terminating adjacent one another such that the two features have space between them sufficient to prevent phase conflicts if both of the two features are defined, at least in part, by phase shifting shapes.