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