Mario,

My suspicion is that your etching chamber is comtaminated, resulting in
teflon or other contaminants sputtering from the walls onto your sample.
A good scrubbing will likely help.

Cary

On Tue, 23 Mar 1999, Mario Adamschik wrote:

> Question for discussion Group:
>
> Subject: SiO_2 RIE
>
> We have problems regarding reactive ion etching with freon
> (CF_4) of thick (1-5um) SiO_2 layers. We use an old PLASMA
> THERM PD 2480 Plasma Etch System 1984.
> Problem: Even after very long etching times we observe high aspect
> ratio "needles" and residues at the substrate (diamond) surface.
> Our process parameters are: 400W, 45mTorr, 45 SCCM CF_4
> We use an Al mask for etching.
>
> Thanks in advance
> Mario
>
>