FOCUS MONITORING MASK HAVING MULTI-PHASE PHASE SHIFTER AND METHOD FOR FABRICATING THE SAME

摘要

A focus monitoring mask includes a transparent substrate, e.g., a quartz layer. A light blocking film, e.g., a chromium-containing film, is disposed on the transparent substrate and has an opening therein. A transparent unit is disposed in a portion of the substrate exposed by the opening. The transparent unit includes a first phase shifter, a second phase shifter and a third phase shifter arranged adjacently in order of amount of phase shift. The second phase shifter is configured to provide an about 180° phase difference with respect to the first phase shifter. The third phase shifter is configured to provide a phase difference other than about 0° and about 180° with respect to the first phase shifter. The transparent unit may further include a fourth phase shifter having a fourth phase difference with respect to the first phase shifter that differs from about 0°, about 180° and the phase difference provided by the third phase shifter.