Hi,

I'm currently coating S1813 photoresist on Si sample. The aim is to get vertical
wall mask for DRIE process on Si (~1.3microns thick).

I have more or less found the exposure time that lead to vertical wall
(almost..). The problem is that the hard bake after development (to reinforce
resist and so raised up the selectivity in DRIE process), changes the resist
profile in a bad manner (geometry "more round", less vertical wall).

I suppose the hard bake time and temperature are critical. I was using 30min at
120°C in oven.

Does someone has better advices?

Is it better to use hot plate or oven?

Is postbake really needed before plasma etching?


Thank you,


Julie.