Patent ID: 6042998
Filing Date: 2000-03-28
Classification: B82Y,G02B,G03F

Abstract:
A method for obtaining a pattern wherein the Fourier transform of said pattern contains high spatial frequencies by combining nonlinear functions of intensity of at least two exposures combined with at least one nonlinear processing step intermediate between the two exposures to form three dimensional patterns comprising the steps of:coating a substrate with a first photoresist layer;exposing said first photoresist layer with a first exposure;developing said first photoresist layer to form a first pattern in said first photoresist layer, said first pattern containing spatial frequencies greater than those in a two dimensional optical intensity image imposed onto said photoresist layer in said first exposure as a result of a nonlinear response of said first photoresist layer;coating said substrate with a second photoresist layer;exposing said second photoresist layer with a second exposure;developing said second photoresist layer to form a second pattern in said second photoresist layer, said second pattern containing spatial frequencies greater than those in a two dimensional optical intensity image imposed onto said photoresist layer in said second exposure as a result of a nonlinear response of said second photoresist layer;combining said patterns to provide a final pattern.