Lithography beamline design and exposure uniformity controlling and measuring

Abstract

The lithography beamline design of Hefei National Synchrotron Radiation Laboratory is presented. A scanning mirror is used to cut off short wavelength radiation and to expand the vertical exposure dimension to 50 mm. A thin beryllium window is installed before the scanning mirror to prevent the longer wavelength radiation from going through. An exposure chamber with a vacuum of 5×10E−7 Torr is located at 7 m downstream from the source point. Because there is no window at the entrance of the chamber, a differential pumping system is used. The scanning mirror is driven by a stepping motor which oscillates through a 1° angle. The required driving speed curve is determined by a computer in order to obtain a uniform exposure area. An in situ moiré fringe grating system is used to measure the uniformity of the motor speed.