Hello,

To add into this, has anyone had much experience performing lithography on
castable polyurethane substrate? We've done some work with the crystal clear
stuff from smooth-on, but our finding is that the temperature of PAB (S1800)
becomes a problem, and there are also some chemical compatibility issues with
developer seen on occasion. Urethane tends to get soft at pretty low
temperatures, and this is a significant problem. I have also been using an
ophthalmic polyurethane as well, which has much better chemical resistance, but
am seeing actual diffusion and bonding of the photoresist to the polyurethane at
very low temperature, 120°F..

Just thought I'd add another question to this, since it's on topic.

Sincerely,
David Casale

-----Original Message-----
From: Dirk Renckens - TNW [mailto:T.J.A.Renckens@tudelft.nl]
Sent: Monday, February 15, 2010 4:29 AM
To: d.alvares@student.unsw.edu.au; General MEMS discussion
Subject: Re: [mems-talk] Polyurethene Mould

Dear Darren,

>From my experience, SU-8 worked fine as a mould for polyurethane (in my case:
Ebecryl 270). The mould did wear out more quickly compared to the use of PDMS -
I expect 5-10 casts of Ebecryl per mould before you need a new one. Hope this
answers your question.

Kind regards,

Dirk Renckens