I'm surprised that polyimide didn't fare very well. Does it swell too much
in toluene to be useful.
My limited understanding of polyimide led me to believe that once it's
imidized, polyimide is very difficult to get rid of. Usually imidization
temperatures are around 400°C, though there are a few low temperature
varieties that imidize around 300°C. Is it possible that you weren't
imidizing? I think there are a lot of useful applications of polyimide that
don't require imidization. It might be possible that you used a recipe for
one of those applications.
Bill Eaton, Ph.D.
Materials & Analysis Manager
NP Photonics
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of David Wood
> Sent: Thursday, May 01, 2003 4:35 AM
> To: [email protected]
> Subject: [mems-talk] process resistant insulator
>
>
> Dear all,
>
> We would like some advice on the best insulator layer to withstand the
> following process steps:
>
> 1. HF/ethanol etch for a few minutes,
>
> 2. toluene at 190 C for 4 hours.
>
> As this insulator will be on already fabricated FETs any
> temperature steps
> cannot be too high. We have tried (unsuccessfully)
> photoresist (S1813 and
> AZ4562), spin on glass and polyimide. We can do PECVD oxide
> and nitride, but
> these will come off instantly in the HF. Would we similarly
> be wasting our
> time with any sputter coated oxides deposited elsewhere - ZnO, TiO2?
>
> Any help for process suggestions with existing materials, or
> new options,
> would be useful.
>
> Many thanks,
>
> David Wood,
> Reader,
> School of Engineering,
> University of Durham,
> South Road,
> Durham,
> DH1 3LE.
>
> Tel: +44 191 334 2464
> Fax: +44 191 334 2407
>
> email: [email protected]
>
>
>
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