You should develop the first layer before you spin the second one.
The SU-8 to SU-8 adhesion is very good, so that no adhesion problems should
occure.
No special precausions are necessary, however you will need to make some
experiments before you find out the right settings for the spinning of the
second layer. In order to fill the existing structures properly with SU-8, I
suggest you pour some more of it on the substrate prior to the spinning.

Good luck

Josef Kouba
BESSY GmbH
Albert-Einstein-Strasse 15
D-12489 Berlin
Tel.: +49-30-6392 2953
Fax: +49 -30 6392 4682
email: [email protected]




----- Original Message -----
From: 
To: 
Sent: Tuesday, February 03, 2004 7:35 PM
Subject: [mems-talk] 2 level SU-8 lithography


> Hello All.
>
>               I am working on 2 level SU-8 lithography now. The first
> layer is about 50um thick and have a feature size of 50um; the second
> layer is 10-20um thickness, the feature size is about 25um.
>
>               I need suggestions right now. Should I develop both layers
> at once after PEB of second layer, or can I develop the first layer and
> spin on the second?
>
>               Also is there any particular precautions I should take in
> 2 level SU-8 lithography?
>
>               I also appreciate if someone can suggest related
> literatures.
>
> best,
> Leidong Mao
>
>
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