Hi all,

   I am trying to fully etch a layer of MPCVD poly-crystalline diamond
(~2um) using RIE. The recipe is 40sccm of O2, 1sccm of CF4, 250W of RF power
and 50mTorr of pressure. Some of the areas are covered by masking layer Ti.
However, I found that there is still a very thin layer of diamond left on
uncovered regions no matter how long they were etched. Could you share with
me your experience? Thanks.

Hoyin