A STUDY OF DEPOSITED CHARGE FROM ELECTRON-BEAM LITHOGRAPHY

This paper presents results from a study of pattern placement errors due to substrate charging in fixed spot direct write electron beam lithography. Experimental results indicate charging-induced errors of over 0.5-mu-m can occur on a grounded Si substrate. Several theoretical models of the charge distribution are presented. Beam deflection due to the monopole field of the accumulated charge predominate over dipole fields in our system and electrons deposited in the Si substrate create negligible pattern placement errors. Finally, about half of the electrons initially trapped in the resist remain there many hours after exposure.