Patent ID: 8685628
Filing Date: 2014-04-01
Classification: B82Y,G02B,G03F

Abstract:
1. A method for forming a grating pattern by large area patterning using interferometric lithography, the method comprising: directing two or more laser beams from a free-running, multimode, pulsed excimer laser without line narrowing through a phase grating with a λ/2 path difference between an upper surface and a lower surface toward a pair of mirrors, wherein the phase grating is operable to suppress zero-order transmission from the laser beams and allow only first-order diffraction beams to propagate through the phase grating onto the pair of mirrors, wherein long-range diffraction from edges of the phase grating does not impact the grating pattern except in a vicinity of an edge of the grating pattern; exposing a first portion of a photosensitive material disposed over a substrate by interfering the two or more laser beams to form the grating pattern; and aligning and overlapping the grating pattern to expose a second portion of the photosensitive material using the laser such that the first portion and the second portion form a grating pattern with a gap corresponding to a step between the exposure areas such that intensity profiles in the first exposure and the second exposure match so that a total exposure fluence is constant across the substrate.