Hi, my sample is composed of 3 layers of 200 nm : low stress silicon nitride / annealed silicon oxide / low stress silicon nitride. I want to etch those layers in one step with using reactive ion etching. The resist I'm using is ZEP520A (300nm thick). The chemistry is based on CHF3, CF4 and Ar, but the etch rate of SiN and SiO2 is to slow compare to the etch rate of ZEP resist. Does anyone has a recipe for silicon nitride and/or silicon oxide etching that is selective to resist ? Thank you for your help, Annabelle Gascon master student, École Polytechnique de Montréal