if you want conformally coat masking material, you can grow PECVD SiO2 or if
metal is allowed in your chamber, use rotating sputtered Al. Then pattern
SiO2 or Al to cover desired areas. Then do shipley PR....
----- Original Message -----
From: 
To: "General MEMS discussion" 
Sent: Monday, January 19, 2004 4:54 AM
Subject: [mems-talk] problem: deep trenches during DRIE


> Hello,
> I need to etch both shallow and deep features using Deep Reactive Ion
Etching.
> The first etch step is fine. However, during the second etch step, deep
> trenches develop at the edges of the features produced during the first
etch.
> I am not sure what this is due to but I think the photoresist (Shipley
9260)
> spin-coated after the first DRIE etch coats the edges only very thinly and
is
> removed during the second etch step.
>
> Any suggestions on how to overcome this will be greatly appreciated.
Thanks.
>
> Regards,
> Melissa
>
>
>