Thank you!!!

    I should say that the beam will bent or twist in the solution ,  or
during the pull out of beam. In fact, in the solution, the beam cannot
stand straight inside the solution.  You can see it in the attachment. It
is taken under the solution

Yours,
Hoyin



>From: "BERAUER,FRANK (HP-Singapore,ex7)" 
>Reply-To: mems-talk@memsnet.org
>To: "'mems-talk@memsnet.org'" 
>Subject: RE: [mems-talk] Sacrifical release
>Date: Wed, 27 Mar 2002 13:06:49 +0800
>
>I do not quite understand your process, but here is what CAN
>happen in some devices:
>When you take the device out of the rinse, a small amount of
>liquid is trapped between beam and substrate. Its surface
>tension will bend the beam towards the substrate. If the beam
>touches the substrate, it might stay there even when the liquid
>is evaporated, due to stiction (which is a big issue in many
>micromechanical devices).
>Here are some ways to verify this:
>- If you can, check if the beam is straigt BEFORE taking out
>    of the solution and only bends AFTER taking out. If so, you
>    clearly have surface tension induced forces as you suspected.
>    Of course, this is not easy to check unless you place the
>    bath under a microscope.
>- Does your beam touch the substrate AFTER the liquid evaporated
>    fully (bake it thoroughly)? If NOT, you probably have film
>    stress induced forces, since stiction only happens on contact.
>Hope this helps.
>
>Greetings,
>       Frank Berauer
>       Senior R&D Engineer
>       Hewlett-Packard Singapore
>
>
>-----Original Message-----
>From: Chan Ho Yin [mailto:hoyincym@hotmail.com]
>Sent: Tuesday, March 26, 2002 8:49 PM
>To: mems-talk@memsnet.org
>Subject: [mems-talk] Sacrifical release
>
>
>Hi all,
>
>      I am a beginner in MEMS field and I am now fabricating a simple
>cantilever beam. The sacrifical layer is Al (~2um). The beam thickness is
>~0.5um and length is ~500um.   When I tried to release the structure using
>AZ300 PR developer, I found that the released beam will bent or twist due
>to the force caused by the fluid flow (PR developer).
>
>    Even I hold the sample carefully, the beam still bent or twist when I
>tried to pull the sample out of the solution. It can't stand straight.
What
>should I do? Is there any technique in handling this??  I guess this might
>too simple to you. But it is important to me.  Can you suggest me with
>detailed steps?  Thank you very much!!!!
>
>Yours,
>Hoyin
>
>
>
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