METHOD FOR DESIGNING PHASE GRATING PATTERN PROVIDING MODIFIED ILLUMINATION AND METHOD FOR FABRICATING PHOTO-MASK BY USING THE SAME

摘要

PURPOSE: A method for designing a phase grating pattern providing modified illumination and a method for fabricating a photo-mask by using the same are provided to improve a process margin by obtaining a desired modified illumination system in a mask system level without modifying an optical exposure apparatus. CONSTITUTION: Arbitrary modified illumination is selected to transfer a predetermined pattern on a wafer in a photo-lithography process(110). An unit region for forming a phase grating portion is set up to provide the modified illumination. The unit region is divided into a plurality of lower cells. A plurality of arbitrary phase values as initial phase values are assigned to the lower cells, respectively. One cell is selected from the lower cells(120). A process for changing a phase value of the selected lower cell is repeatedly performed to change the arrangement of the phase values assigned to the lower cells and find the arrangement of the phase values corresponding to the modified illumination(130-160).