Hello,
On
http://www.microchemicals.com/lithography/photoresist_1422.html
we give some information how to avoid/remove an edge bead. Especially for
thick resist films, it may be necessary to give the film short prebake
before edge bead removal. This will help to evaporate a certain amount of
solvent (reducing the formation of defects in the film by droplets of teh
edge bead remover), but not completely dry the resist film which would
significantly prolong the edge bead removal process.
Best regards!