DISTRIBUTED DENSITY MASK AND METHOD FOR PRODUCING THE SAME BY MULTISTAGE EXPOSURE METHOD

摘要

PROBLEM TO BE SOLVED: To inexpensively and easily produce a distributed density mask at a high production speed without requiring a special equipment.;SOLUTION: A mask blank is divided into unit cells and light transmissive regions or light shielding regions of the respective unit cells are determined. The determined light transmissive regions or light shielding regions are disposed on each gird and necessary pattern forming frequency, focal depth and beam diameter are calculated by CAD(computer aided design) and converted into data. A sensitive material on the mask blank is multistage-patterned by prescribed frequency on the basis of the data under prescribed conditions (focal depth and beam diameter) and the mask blank is developed and rinsed to obtain a three-dimensional sensitive material pattern. The shape of the sensitive material pattern is transferred to a light shielding film by etching.;COPYRIGHT: (C)2002,JPO