Dear Soojin,

        Actually, 1813 can partially withstand alcohol (ethanol) after
being crosslinked.  Crosslinking can occur when the resist is exposed
to UV while free of moisture.  The easist way I know to do this is to heat
the 1813 to 160C while simultaneously irradiating with ~1.5 mW/cm2 UV for
6 minutes. For example, with a uv light hung above a hotplate.  The 1813
can still be removed with acetone. There are two disadvantages, though.
First, the 1813 will crack, but not wash away, under ethanol.  Second, the
1813 will reflux slightly, which may be a problem for features smaller
than a few microns.


Darren S. Gray
Johns Hopkins University
Department of Biomedical Engineering
Baltimore, MD, USA
e-mail: dgray@bme.jhu.edu

> Date: Tue, 19 Nov 2002 12:14:30 -0800 (PST)
> From: Soojin Oh 
> To: mems-talk@memsnet.org
> Subject: [mems-talk] any photoresists ok with alcohol?
> Reply-To: mems-talk@memsnet.org
>
> Dear mems talk members,
>  I am currently using shipley 1813 photoresist. This
> PR dissolves in ethyl alcohol. I'd like to know if
> there's any other photoresist(positive type preferred)
> which will survive ethyl alcohol. (Just immersing in
> ethyl alcohol for 5 minutes or so.) If there is a
> photoresist which survives alcohol, how do I remove it
> later?
> -Soojin Oh
>  UNC-CH