Patent ID: 7018783

Claim:
An optical equipment comprising an optical device having a stepped diffraction pattern formed on a substrate by a method comprising: a first step comprising forming a first masking pattern comprising a first masking material in a pattern of lines, spaces and recessed portions on said substrate, wherein the recessed portions are in the spaces of said first masking pattern; a second step of forming a second masking pattern comprising a second masking material in a pattern of lines and spaces on said substrate by filling the recessed portions formed on said substrate by said first step with said second masking material, wherein the spaces of said second masking pattern correspond to the lines of the first masking pattern; a third step comprising forming a third masking pattern by etching a portion of the lines of said first and second masking materials, and a fourth step comprising etching said substrate through said third masking pattern, said third masking pattern comprising non-etched portions of said first and second masking pattern.