I am using photo lithography resist as the mask to etch SiO2 to create a rectangular feater on a silicon with DLC overcoat, i.e. the layer structure goes Si, DLC, SiO2, resist. The thickness of SiO2 is around 400A. When we do RIE etch in a STS tools, we see redep indicated by "horns" sticking up on the side of the walls. I am trying to figure out how this can be avoided. Thanks, Mike