Self-aligned method of making phase-shifting lithographic masks having three or more phase-shifts

摘要

A phase-shifting lithographic mask having two or more self-aligned phase-shifting regions is fabricated by a sequence of etchings of the phase-shifting mask using a protective resist layer having three or more regions (411, 412, 410, 401) that have been subjected to mutually different doses (including possibly zero) of actinic radiation--such as electron beam, ion beam, or photon beam radiation. A self-aligned opaque region (901) can be supplied by in-situ carbonization of remaining resist material.