Hi

I am trying to write ~ 1 micron features with e-beam writing, but I
would like my resist be very thick - about 5 micron, so the aspect
ration of the vias as developed in resist would be 1:5. I tried using
thick PMMA , but I could never remove the resist completely from the
exposed areas, even when exposed with very high doses and after very
long development time. Can anyone recommend any e-beam resist +
processing conditions, which are more appropriate for this purpose?

Thanks

Mark