### 6.5.3 Summary to: Etching Techniques

| Chemical etching: Relatively simple, with luck extremely selective, relatively fast, but: |  |
|  | Material removal always isotropic (see figure) and thus enlarging features and thus not applicable to "micro" or better "nano" structuring |
|  | Might be extremely dangerous (corrosive, poisonous, inflammable, explosive, ... ) and often hard to recycle / dispose off. |
| Plasma Etching: Simple in principle (see figure) quite complex and expensive in praxis. |  |
|  | Given the right plasma (not easy to find; plasma chemistry counts among the "black arts"), the etching can be completely anisotropic and sufficiently selective. |
|  | Innumerable variants exist and new methods are coming up all the time. Definitely on of the key technologies for micro / nano technology. |

© H. Föll (Electronic Materials - Script)