NOVEL ILLUMINATION SYSTEM OF SYNCHROTRON-RADIATION STEPPER WITH FULL-FIELD EXPOSURE METHOD

We estimate the pattern distortion and the critical dimension (CD) var iation due to the thermal distortion under a large exposure field for the full field exposure method. We verify that the effect of the therm al distortion of the mask and wafer on the pattern distortion and the CD variation is small enough under the condition of mass production of devices of 0.1 mu m design rule. We present a design of the novel two mirror illumination system which can improve the throughput both by e xposing a field as large as 50 mm square and by condensing synchrotron radiation (SR) spread in the horizontal plane. The effects of the var iation of the position of the SR source and the mirrors and the size o f the SR source on the performance of the stepper are investigated. (C ) 1997 American Vacuum Society.