Dichromatic photomask and a method for its fabrication

摘要

A method of manufacturing a photomask for the production of dual depth features on substrates, and the photomask so manufactured, wherein the method of manufacturing the photomask is comprised of the steps of: (1) coating a substrate which transmits at least two selected wavelengths with: a) an optical filter material which prevents the transmission of at least one of the wavelengths, b) an opaque masking material, and c) a dual tone photoresist; (2) using a single mastering tool to selectively expose areas of the coated substrate to one of the wavelengths; (3) developing the photoresist; (4) etching the exposed masking material and optical filter material; (5) exposing the remaining coated substrate; (6) developing the remaining photoresist; (7) etching the exposed surface; and (8) stripping away the remaining photoresist.