X-ray masks may be fabricated with features that have parabolic rather than the usual rectangular or trapezoidal cross sections. Phase shift effects in such features cause them to act as tiny lenses that focus the x rays on to the wafer. The lenses may either be cylindrical, to form line images on the wafer, or spherical, to form points. Wider images, with very sharp outlines, may also be formed on the wafer by using wider mask features, which have parabolic cross sections only near their edges. Features down to at least 50 nm may be imaged, with wide latitudes in mask parameters, gap, and resist processing.