Etch Profile Lab: Why Only the Synergy Cuts Straight Down

One masked substrate, three ways to remove material. Watch the shape each mechanism carves — the profile is the whole story.

Schematic teaching model. The mechanism contrast is the textbook one — neutral radicals etch in all directions (undercut), ions alone etch line-of-sight but slowly and eat the mask, and ion-assisted chemistry etches fast and vertically, with sidewall passivation protecting the walls — but rates, geometry, and the passivation graphics are illustrative, not a feature-scale simulator, and the depth readout is a relative scale, not nanometers. Real profiles also depend on pressure, bias, chemistry, aspect ratio, and temperature.