Dear Anpan,

even though I´m not a specialist in MEMS, I had a lot of "bubble free"
application when I worked in the vacuum industry. The reasons are always the
same:

1) trapped air in cavities --> evacuate and fill under vacuum
2) outgasing of the liquid (dissolved air/moisture) --> degas the liquid
before filling (as everybody knows for cars and brake fluid!)

By applying a plasma before filling you can reduce the contact angle of the
liquid on your substrate (i.e. increase wetability), which means that you
fill the cavities in a way that it will be less likely produce bubbles,
allowing the gas to escape though the center while filling the cavities from
the perimeter. Another nice advantage might be be a possibly shorter filling
time, as it has been demonstrated for capillary flip-chip underfill.

Best regards

Thilo Semperowitsch




-----Ursprüngliche Nachricht-----
Von: HAN Anpan [mailto:[email protected]]
Gesendet: Montag, 10. Januar 2005 11:42
An: General MEMS discussion
Betreff: [mems-talk] 1/(How to get rid of the
bubblesinthemicrofluidicdevice)


Dear all

Back to the annoying bubbles. We try everything to get rid of them, but
does anyone have an idea how they formed. Maybe then we could find
better ways to eliminate them. A reference on this issue will be great!

All the best

Anpan
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