I am working with a RIE machine O2 etching a thick layer (50um) of an
organic (LCP). After etching through most of the depth, there is a black
residue left on the sample. My guess is this is oxidation byproducts
from the etch - anyone know with more certainty?

If that's it, what would help sweep the residue out? Increased flow
rate? On this system it appears that all I can do there is hook up a
higher capacity pump in order to increase gas flow rate while keeping
the pressure in the same range.

Thanks for any insights.

Linas.