Phase shift has been seen by many as a route to increase the resolution capability of optical microlithography beyond the Rayleigh criterion. The initial enthusiasm with which this technology was greeted has been moderated by the realization that prior to its practical application many technical challenges must be overcome. Nevertheless progress has been made. The question to be answered is no longer whether phase shift works, but rather which phase-shift approach and manufacturing technique provide the best practical solutions. We compare three techniques to build alternating phase-shift reticles: (1) deposited spin-on glass (SOG), (2) chemical vapor deposition (CVD) silicon dioxide, and (3) etched quartz. The merits of each approach are judged in terms of lithographic performance, ease of manufacture, and reliability. We condude that the SOG approach offers the best short-term solution to the manufacture of alternating phase-shift masks, although its lithographic performance is somewhat inferior to the other two and its long-term reliability remains to be determined. For deposited oxide to be a viable long-term approach, the oxide must be deposited under the chrome; for etched quartz, the roughness and defect density must be controlled.