Hi Ning Wu,
I'll second that, I notice that pressure has a small, but decent, effect on
Si/Ox Selectivity ( reduced Ion energy, in my chamber >150mT) but more
importantly I found that the addition of O2 (>>10%) to the SF6 discharge
really does wonders to the selectivity ( Si/Ox climbs to >15 ). You'll need
to do a small DOE to find your optimal.
Regards, Eric


--------------------------------------------------------------------------------
--------------------------------------------------
> Message: 6
> Date: Wed, 20 Jun 2007 16:55:47 +0530
> From: "abhaya joshi" 
> Subject: [mems-talk] Re: Selective RIE etching of silicon over silicon
>         oxide
> To: [email protected]
> Message-ID:
>         
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> hi Ning Wu,
> you can go for SF6 based RIE. it wont affect Oxide. salectivity of Si over
> Sio2 is always higher then >5.
> -abhay joshi
> university of Pune.
> India