IMPROVEMENT OF PATTERN AND POSITION ACCURACIES BY MULTIPLE ELECTRON-BEAM WRITING FOR X-RAY MASK FABRICATION

To study the improvement of position and line-width accuracies of resi st patterns for X-ray masks, we tried to examine multiple writing with an electron beam (EB) exposure system. First, the uncertainty of the position measurement is checked and reduced to 0.03 mum (3sigma) by th e short-length measurement method. Then, it is found that by increasin g the number of writing times from one to four, the overlay accuracy i s improved from 0.04 mum to 0.02 mum (3sigma) and the line-width of th e pattern is exactly controlled. These results show that sub-quarter-m icron patterns are formed by the multiple-writing method with the pres ent EB machine.