The problem could be undercutting of your small features.
I have found CR-7 to have an incredible undercut whether I am using
photoresist or even gold as the mask for the Cr.
If you are using Cyantek CR-7 as your chromium etchant, try Cyantek CR-14
instead, which
gives much less undercut (a factor of three, according to my measurement).
        Kirt Williams, Ph.D.    consultant

----- Original Message -----
From: PIMPIN Alongkorn 
To: 
Sent: Friday, March 14, 2003 8:31 PM
Subject: [mems-talk] Photoresist delamination problem


> Dear All,
>
> I work with Cr/Au/Cr layer on PDMS.
> I have found the problem about the delamination of
> Photoresist after dipping in Cr etchant.
> My processes are
> - Spinning PDMS
> - E-beam depositing Cr/Au/Cr (10/300/10 nm thick)
> - Spinning Photoresist (AZP 4400) with adhesive promoter and curing at
room
> temp 1 day
>    (I couldn't bake at 100 c coz there was cracking on PDMS layer)
> - developing pattern 20 um-wide of Photoresist
> - And then etching Cr/Au/Cr layer by first dipping in Cr etchant
>
> Then the problem occured. Photoresist pattern peeled off in particular
> smaller patterns went first. I have worked on Cr/Au/Cr etching before on
Si
> wafer.
> I have never found the problem like this.
>
> Could you please advice me or suggest me from your experiences?
> I will be very appreciated your help.
>
> Best regards,
>
> Alongkorn Pimpin
>
> -------------------
> Alongkorn Pimpin
>
> Turbulence and Heat Transfer laboratory,
> Department of Mechanical Engineering,
> School of Engineering,
> The university of Tokyo.
> tel: 03-5841-6419
> fax: 03-5800-6999
> email: pimpin@thtlab.t.u-tokyo.ac.jp
>
>
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