Performance of a compact beamline with high brightness for x-ray lithography

We have developed a short beamline with high brightness for x-ray lithography. The beamline contains a single, a scanning toroidal mirror and a vacuum-protection system with an acoustic delay line. The practical exposure intensity on a wafer was approximately 50 mW/cm2 at stored electron current of 500 mA. Dose uniformity of ±2.8% was achieved in a 26 mm×26 mm exposure area by optimizing the scan speed. Minimum resolution of 80 nm was obtained with a 15 μm gap. The optimum dose for TDUR-N908 (Tokyo Ohka) was 1300 mA s, which corresponds to exposure time of 2.6 s when the stored electron current is 500 mA. Since the sensitivity of TDUR-N908 is 110 mJ/cm2, the beam intensity in our beamline is estimated to be 43 mW/cm2. By reducing the exposure field, a beam intensity of more than 50 mW/cm2 can be achieved.