Abstract: A method is described for repairing a defect detected in a photolithographic mask. A phase voxel cavity is formed in the photolithographic mask to compensate for the defect in the photolithographic mask. The phase voxel cavity and features of the mask both create a phase shift of approximately ?.

Abstract: A metrology pattern on a reticle comprising a phase-shifted feature and an additional phase-shifted feature and/or non phase-shifted feature is disclosed. The metrology pattern can be used to determine the target thickness for achieving 180.degree. phase difference, i.e., zero phase error on a phase-shifted reticle. A test reticle having several such metrology patterns, with several different phase-shifter thickness differences is used to produce a CD versus defocus data for each of the phase-shifter thickness differences by performing an exposure matrix or series of aerial images. The data can be used to determine a target thickness for zero phase error. The data can also be used to determine a correlation between focal shift, phase error, and shifter thickness. The metrology pattern can be placed on reticles used for the fabrication of semiconductor devices, for example, so that an exposure matrix can be performed, to determine any focal shift, which can then be related to phase error.