Hi Helene,

You asked about the depth resolution while etching. Well "generally
speaking" you can reach any resolution you need. If you use a Bosch process
based recipe, then you know that the etching step has a certain duration,
hence a certain depth per cycle. If you want to reach better depth control,
you simply reduce the cycle time by reducing each steps duration. The
smallest resolution you reach is depending on the massflows/pumping system
and gas time travel to the chamber. Typically this is roughly 1 or 2s
depending on the reactor you are using. Lower cycling duration while make
your plasma to be a mixture instead of pure etchant/passivant.

As a result, reaching a high control on the depth will have the drawback to
increase the etch time, but plasma etching is always a matter of compromise
isn't it?

Best regards,

Gabriel Roupillard
e-mail:  [email protected]