Patent ID: 7387965
Filing Date: 2008-06-17
Classification: G01N,G03F

Abstract:
1. A method of forming a reference pattern for creating a defect recognition level, comprising: forming a light-shielding layer on a transparent substrate; patterning the light-shielding layer to form a first light-shielding pattern and a second light-shielding pattern adjacent to the first light-shielding pattern, the first light-shielding pattern being formed of a single pattern covering the overall surface of a portion of the transparent substrate, and the second light-shielding pattern being formed of a plurality of parallel line patterns to form line-shaped openings exposing the transparent substrate, wherein each parallel line pattern has a length that is substantially longer than a width; etching the transparent substrate using the first and the second light-shielding patterns as an etch mask to form trench lines corresponding to the line-shaped openings, the trench lines having a depth such that light transmitted therethrough has a phase difference with respect to light transmitted through the transparent substrate between the trench lines; and removing the first and the second light-shielding patterns to form a blank region corresponding to the first light-shielding pattern, and a grating region corresponding to the second light-shielding pattern and the line-shaped openings, wherein the blank region and the grating region are used for creating a transparent defect recognition level, wherein intensity of light transmitted through the grating region is lower than intensity of light transmitted through the blank region due to interference between the light transmitted through the trench lines and the light transmitted through the transparent substrate between the trench lines, which have the phase difference, wherein the trench lines have a depth such that light transmitted thereto has 180 degrees of phase difference with respect to light transmitted through the transparent substrate between the trench lines.