Hi Josef,

        You need a PR process that gives you 60 nm feature size for
etching 800 nm thick Si layer. That means the aspect ratio of your etched
feature will be 13? This is very high aspect ratio and will your Si
features collapse after etching? sub-micron thick AZ resist is definitely
available. One of them I can name is AZ3312, which we are using now. But
don't know if it can be used as e-beam resist, and will it be capable of
resolving 60 nm features. I think this resist can go down to about 500nm
thick. That means the resist line, if it can resolve 60nm features,
will have an aspect rato more than 8! The features will probably collapse
after development.

Yours sincerely,

Isaac Chan
University of Waterloo