Improvement of position accuracy in mask-writing electron beam lithography with a multi-pass writing strategy for reducing positionerrors due to resist charging

摘要

This paper presents an experimental study of resist charging of mask blanks written with a variable shaped electron beam mask writer. Experiments were performed at a current density of 40 A/cm~2 on mask blanks with a chemically amplified resist. Test patterns were written to examine the magnitude of the pattern shift due to resist charging and the distance within which the pattern shift is significant. To reduce the pattern shift due to resist charging, furthermore, similar test patterns were written with a two-pass scanning in which both horizontal and vertical scanning directions are different between the two passes. With this writing method, the pattern shift was successfully reduced to about half.