Patent ID: 6524756
Filing Date: 2003-02-25
Classification: C03C,G03F

Abstract:
A method of fabricating a three-dimensional diffractive optical element within photoresist which is coated on a substrate selected from a group consisting of quartz glass, silicate glass, germanium, and an optically transmissive material comprising:providing a HEBS-glass photomask blank having a body portion and a surface layer formed thereon which is responsive to electron beam radiation to change the optical density of the surface layer; exposing the HEBS-glass photomask blank to an electron beam of selected charge density over a grid of discrete locations on the photomask blank to provide a predetermined gray scale pattern of varying optical transmissivity on the photomask blank to produce a gray scale mask; exposing the photoresist layer to radiation transmitted through the mask; and removing material from the photoresist layer to provide a predetermined varying thickness of the photoresist layer as determined by the gray scale patterns on the gray scale mask to produce the three-dimensional diffractive optical element.