A process for creating and verifying a design of phase-shifted masks utilizing at least one phase shift region employing a computer-aided design system. A chip design is provided. A phase-shift mask design capable of producing the chip design is created. Features in a design of the phase-shifted mask that require phase shifting are located. Uncolored phase regions are created on opposite sides of the features. Proper phase termination of the phase regions is ensured based upon space constraints of a phase-shifted mask technique utilized. Phases are determined for the phase regions. Whether coloring errors and un-phase-shiftable design features exist is determined. Mask process specific overlaps and expansions are applied to the mask design to prepare designed data levels for mask manufacture. A residual phase edge image removal design is derived.