PROJECTION EXPOSURE SYSTEM

摘要

PURPOSE: A projection exposure system used as a modified illumination method is provided to improve a uniformity of patterns by minimizing the difference between the zero order intensity of light source and the first or more order intensity. CONSTITUTION: The light generated a light source(210) is converted to a horizontal light by passing a fly eye lens(212) and irradiated into a mask(218) by a tilted angle via an annular aperture(214) and a condenser lens(216). The intensity of a zero order diffracted light passed through a first projection lens(220) is gradually decreased due to a transmittance controlling film(223). The zero order diffracted light controlled by the transmittance controlling film(223) and a -1st order diffracted light are selectively exposed to a photoresist of the wafer, thereby preventing increase of the difference of critical dimension.