Dear colleagues,

I am trying to pattern negative photoresist on a ceramic substrate using
contact lithography, and it seems that features which should be shadowed by
the chromium on the mask are becoming exposed, and won't develop out. I
suspect that UV light is scattering off the substrate and entering the
regions that should be in shadow, but I could easily be wrong.

Does anyone have any experience with this effect? If so, your input would be
most appreciated.

Thanks,

Adam Cohen