Yesterday I wrote a protocol for an experiment we did at the university, creation of simple structures on a glass substrate by metalization and lift-off.

We did the experiment some months ago, so I couldn’t remember exactly what the purpose of one step was: soaking the substrate with the exposed photo resist in chlorobenzene for 10 minutes prior to developing. I did a little Google research and came across this page (since moved to here, but the pictures don’t work).

Turns out this is done so that the surface of the photo resist develops more slowly than the underlying layer, giving some “undercutting” when developing for a longer time than usual. This helps with the lift-off step after the metalization.