Thank you. I just did it and there were several small regions with foam. I
remember when I under exposed su8 rinsing it with IPA caused the whole wafer to
be covered with foam. I had no idea why.


-----Original Message-----
From: [email protected] on behalf of
Matthieu Nannini
Sent: Mon 7/7/2014 6:44 PM
To: [email protected]
Subject: [mems-talk]  Unremoved SU-8 after exposure

Quick test: do you rinse the PGMEA with IPA ? If yes, any not cross
linked SU8 should react and release a white-ish foam. If it does it
means it's crosslinked already in which case you'd have to turn to your
exposure method and find out what's wrong.

[email protected] a écrit :
> Hello,
>
> I am graduate student in Brooklyn College and I am trying to reinvent the
wholeMEMS  procedure as I do not have any professional help. My science adviser
is from another field.
>
> I am having difficulties with the developing of SU-8 2025. Here is what I am
doing:
>
> I am spin - coating 4 inch Si or Pyrex wafer to 50 - 60 um thin film
> Pre - baking at 96 degrees for 15 min
> Sometimes instead I am putting the wafer in the vacuum chamber of my UV
imprinter. The vacuum is taking away the solvent and clear most of the bubbles.
> UV exposure with a hand made Imprinter: Xenon lamp 22kV at 10 microsec.
pulses. Three 30 seconds exposures with couple of seconds pause.
> UV lamp creates heat so the wafer is let for 2 - 3 min to relax.
> Post bake of 15 min at 95 degrees.
>
> Developing by tenderly shaking the wafer in a vessel with Propylene glycol
monomethyl ether forever.
>
> The result is that I clearly can see my pattern as exposed SU-8 is yelowish
but the unexposed parts are not removed and form thin film with the exposed
part.
> Less exposure leads to removing all of the polymer.
> (This is happening even without any mask but the pattern is formed by metal
structure that divides 4 inch wafer into several smaller regions.)
>
> Can anybody figure out what is my mistake?
>
> Thank you
> Dimitar Dimitrov
>
>
> ------------------------------
_______________________________________________
Hosted by the MEMS and Nanotechnology Exchange, the country's leading
provider of MEMS and Nanotechnology design and fabrication services.
Visit us at http://www.mems-exchange.org

Want to advertise to this community?  See http://www.memsnet.org

To unsubscribe:
http://mail.mems-exchange.org/mailman/listinfo/mems-talk