Image-placement control with electron-beam lithography is directly inf
luenced by charging effects during exposure. One of the primary chargi
ng sources is the buildup of electrons in the nonconductive resist fil
m, We have evaluated the use of a conductive-polyaniline film as a top
coat over the resist during exposure, Critical parameters including im
age-size variation, image placement, and defect density were compared
for masks with and without the conductive-polyaniline topcoat. It was
found that the performance is dependent on the resist exposure dose. F
or a low-sensitivity resist (i.e., a resist requiring high exposure do
se), significant improvements for image size and image placement can b
e achieved with the implementation of a conductive topcoat. For a high
-sensitivity resist (i.e., a resist requiring low exposure dose) with
single-pass writing, preliminary results show that charging is current
ly not the primary driver of image-placement errors. (C) 1997 American
Vacuum Society.