So you have a long-ish 5 micron channel that is open only at the ends?
If that is the case there is no way the oxygen radicals will get inside.
I think the mean free path length at 100's of mTorr is around a
centimeter. You will need to use some sort of wet chemistry. I think a
strong base might work, check the literature.

-Mike


>>> [email protected] 03/25/04 4:30 PM >>>
Hello everyone,
I am trying to make a PDMS channel using PR-1827 as a sacrificial layer.

The height of the photoresist is 5 um, and then i spin a 5 um coat of
PDMS
on it. Etch away the PR and get a channel under the PDMS.

The problem I am facing is that the channel doesn't become hydrophilic
even after I put it in Oxygen Plasma. I have done 10 mins at 450 mT at
100W. The outside of the PDMS does become hydrophilic.

Am I working with too small of a channel depth or am I overlooking
something?? Do I need to treat it with Oxygen plasma for a few hours??

Please advise, as I have been stuck with this problem for
quite some time.

Thanks in advance
tushar

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