It's overheating.

Try to improve the cooling or if the He is already high, add a pause in the
recipe every few minutes to let the wafer temperature equalize


-----Original Message-----
From: mems-talk-bounces+shay=mizur.com@memsnet.org
[mailto:mems-talk-bounces+shay=mizur.com@memsnet.org] On Behalf Of Sarah
McQuaide
Sent: Friday, September 30, 2011 2:29 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Avoiding photoresist reticulation (burning) during DRIE

I sometimes see photoresist reticulation during a device release step using
DRIE, mainly on devices at the edge of the wafer where the release first
happens. Has anyone experimented with ways to avoid resist reticulation
during DRIE? This is a thick resist, challenging to remove later using a
required dry etch.