Sebastian,
For peeling off PDMS conveniently, silanize the silicon wafer surface that
has SU-8 patterns.  This can be done by keeping the wafer in a vacuum
dessicator along with about 50 microliters of (3-Aminopropyl)
triethoxysilane (also called as 3-APTES) for at least 3 hours. The vapours
of 3-APTES forms a layer of silane on the surface of the wafer that ensures
smooth peeling of PDMS after curing.
Good luck!



--------------------------------------------------------------------
Bhuvaneshwari K

Research Scholar
c/o Professor Soumyo Mukherji
Biosensors and Bioinstrumentation Group
Department of Biosciences and Bioengineering
Indian Institute of Technology, Bombay
Powai, Mumbai, India.
Mobile Number : +91 99 8767 9533.
Email : [email protected]; [email protected]
--------------------------------------------------------------------


On 25 February 2014 09:01, Sajeesh P  wrote:

> Apply some HMDS coating over the silicon wafer befor spinning the SU8.HMDS
> will improve the adhision between Su8 and Silicon
>
>
> On Mon, Feb 24, 2014 at 8:08 AM, Sebastian R Freeman <
> [email protected]> wrote:
>
> > Hello everyone,
> >
> > I am a graduate student making microfluidic devices for the first time. I
> > am processing SU-8 2050 negative photoresist on a silicon wafer to try
> and
> > produce a porous PDMS membrane. My difficulty lies in producing the the
> > SU-8 structures. I have been having adhesion problems, as well as getting
> > my structures to develop uniformly. The pattern I am trying to make is
> > composed of an array of tiny cylindrical posts 50 micros high, with a
> > diameter of approximately 5 microns, and spaced 15 microns apart from
> each
> > other.
> >
> > The PDMS spin coating is also creating difficulties. When I attempt to
> peel
> > off the PDMS from the SU-8, the PDMS rips off my posts. I have applied
> > Sigmacote as I was told this would lessen the adhesion between PDMS and
> > SU-8, but it appears to have only helped minimally.
> >
> > If anyone has any good advice or suggestions of new approaches, I would
> be
> > most appreciative. Thank you.
> > _______________________________________________
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>
>
> --
> Sajeesh P
> Research Scholar
> HTML Lab
> Mechanical Engineering Dept
> IIT Madras
> _______________________________________________
> Hosted by the MEMS and Nanotechnology Exchange, the country's leading
> provider of MEMS and Nanotechnology design and fabrication services.
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_______________________________________________
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