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As the semiconductor industry enters the subwavelength era where silicon features are much smaller than the wavelength of the light used to create them, a number of "subwavelength" technologies such as Optical Proximity Correction (OPC) and Phase-Shifting Masks (PSM) have been introduced to produce integrated circuits (ICs) with acceptable yields. An effective approach to subwavelength IC production includes a combination of these techniques, including OPC and PSM. Nevertheless, as we approach silicon features of 100 nm and below, Alternating PSM (AltPSM) becomes a critical part of the technology portfolio needed to achieve IC requirements. An effective EDA methodology that generates AltPSM ICs must guarantee correct generation of AltPSM layouts, maintain today's design productivity, and leverage existing tools and flows. The implementation of such a methodology becomes more complex as phase shifting is applied to all critical features, including those outside transistor gates. In this paper, we present a methodology targeted for standard-cell or structured-custom design styles. We also present examples of designs that start from standard-cells created in a manner in which all issues regarding generation of AltPSM are effectively considered, and are then used in a typical cell-based (synthesis-automatic place and route) flow to produce design layouts that are ready for cost-effective silicon manufacturing.