Hi Yawei,

Although I've never encountered this problem with the image reversal =
resist,  I've encountered a similar problem with a positive resist.  It =
turned out to be that the substrate surface was not totally clean.
=20
Perhaps you need to review your substrate cleaning procedure?
=20
Good suggestions for substrate cleaning using piranha solution have been =
made in previous mems-talk emails.
=20
Good Luck!!!
=20
Andy Henderson
=20
Teesside Centre for Nanotechnology and Microfabrication,
School of Science and Technology,
University of Teesside,
Borough Road,
Middlesbrough,
Tees Valley.
=20
TS1 3BA.
=20
Tel: (01642) 342 428

________________________________

From: mems-talk-bounces@memsnet.org on behalf of Yawei Li
Sent: Fri 24/03/2006 18:05
To: mems-talk@memsnet.org
Subject: [mems-talk] help needed for image reversal photoresist AZ5214 =
withabout 3um thickness



Hello everyone,

I am working on the image reversal photoresist AZ 5214 (about 3um
thick)on 4" Si wafer with undercut profile for metal liftoff.

The recipes I tried are as follows:

HMDS
Spin @ 1000 rpm for 45 sec
prebake 95 degree 60 sec on hotplate
Image exposure   5-40 sec at 8.8mW/cm^2
PEB   115 degree for 1-2min on hotplate
Flood exposure 27-120 sec at 8.8 mW/cm^2
Development in AZ 400K (1:4)

But I could not get the feature clear before the exposed area peel off
even I increase the imagewise exposure dose and PEB.

Does anyone have experience with AZ 5214 for 3um thickness?  Can you
share your recipe with me or give me some suggestion about the recipe?