US Patent 7332098 Phase shift mask and fabricating method thereof

The present invention provides a phase shift mask and fabricating method thereof, by which a critical dimension of a semiconductor pattern can be accurately formed in a manner of compensating a boundary step difference between an active area and an insulating layer. The present invention includes a transparent substrate and at least two halftone layers on the transparent substrate to have light transmittance lower than that of the transparent substrate, each comprising front and rear parts differing in thickness from each other.