Use of chromeless phase shift features to pattern large area line/space geometries

Abstract

Method for using chromeless phase shift lithography (CPL) masks to pattern large line/space geometries. The method comprises using light at a wavelength of one of 248 nm, 193 nm, or 157 nm to illumimate a CPL mask comprising a reticle having a plurality of phase-shifting features interspersed with non-phase-shifting areas arranged in a substantially alternating two-dimensional pattern. When light passes through the phase-shifting features it is phase-shifted relative to light passing through the non-phase-shifting areas of the CPL mask. The phase-shifted light and non-phase-shifted light passing through the reticle are then projected onto a resist layer applied over a semiconductor substrate. The resultant composite aerial image intensity distribution is such that an area of the resist having a shape defined by a periphery of a corresponding pattern of phase-shifting features is sufficiently exposed to pattern a large area feature in the resist. Subsequent semiconductor processing operations may then be performed to pattern a corresponding feature on the semiconductor substrate.