A chromeless phase-shift mask (CPM) for imaging sub-100 nm contact holes and a method of making the same are disclosed. The CPM includes a plurality of features formed on a substrate and a plurality of suppressors formed on the substrate. Light energy passing through the plurality of suppressors substantially reduces an interference generated by light energy passing through features within an optical proximity of each other, thereby significantly improving contrast and depth of focus. The plurality of features can be formed in a grid pattern, and the suppressors can be formed in adjacent corners of each feature. The size and location of the suppressors can be varied with respect to the features to obtain a desired image.