Method of fabricating phase shift reticles including chemically mechanically planarizing

摘要

A method of fabricating phase shifting reticles that can be used as a mask in photolithographic processes such as semiconductor wafer patterning. An opaque film such as chromium is first deposited on a transparent substrate. The opaque film is then patterned with openings by a first photolithographic step. A phase shifter material such as (SiO2) is then deposited into the openings to form phase shifter sections. The phase shifter sections are then polished by chemical mechanical planarization (CMP) to a thickness "T" which is selected to produce a 180 DEG phase shift. A pattern of light apertures is then formed by a second photolithographic process in the opaque film such that a reticle having a repetitive phase shifting pattern is formed.