Patent ID: 6534223
Filing Date: 2003-03-18
Classification: G03F

Abstract:
A method of forming a circuitry fabrication mask having a subtractive alternating phase shift region, comprising:forming a light shielding layer over a light transmissive substrate; patterning the light shielding layer to have at least a portion having a first series of openings which alternate with a second series of openings; effectively masking one of the first series of openings or the second series of openings while leaving the other of the first series of openings or the second series of openings effectively unmasked; while the one openings are effectively masked and the other openings are effectively unmasked, ion implanting a species into the light transmissive substrate through the other openings, the implanted species increasing a wet etch rate of the light transmissive substrate in a wet etch chemistry compared to the light transmissive substrate which is not effectively implanted with the species; and wet etching the species implanted light transmissive substrate through the other openings substantially selective to the light transmissive substrate which is not effectively implanted with the species effective to at least partially form alternating phase shift regions through the other openings as compared to the one openings.