There may not be any SU-8 that can be used for depositing a layer below
1 micron. However, there are a couple of possibilities:

1. Use the original formulation of SU-8 2(not SU-8 2002).  The solvent
in this material (GBL) is fairly low vapor pressure, so spin time can
actually be a factor in film thickness (longer spin time - thinner
film). If you can enhance this further by using a coater with an
integrated bowl cover (such as an EVG150), and high speed spin
capability (10000rpm), you may be able to use this formulation to get
below 1 um.

2. Dilute the SU-8.  Depending on which version (SU-8, SU-8 2000),
MicroChem (or whoever is the distributor in your area) makes a thinner
that would allow you to reduce the solids content of the material, again
allowing spinning below 1 um.

Best Regards,
Chad Brubaker


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Prem Pal
Sent: Wednesday, January 11, 2006 11:08 PM
To: General MEMS discussion
Subject: [mems-talk] SU-8 layer less than 1 um

Dear Researchers
Which SU-8 should I use for depositing a layer of thickness less than 1
um. If any have done it, please give me the recipe for achieving this
thickness by spin coating.
Thanks in advance

Prem Pal
Yonsei University Seoul