Hi Brad,

Thank you very much for your explanation. Just I searched precision glass sphere
or bead, but I couldn't find a proper supplier. Do you know one to introduce it
to me? Also, I used frit tape instead of paste. Do you think if I use glass frit
paste it flows to the cavity due to high pressure and temperature?

Best regards,
Reza

________________________________
From: Brad Cantos 
To: rrashidi@mech.ubc.ca; General MEMS discussion 
Sent: Saturday, January 24, 2009 2:07:13 PM
Subject: Re: [mems-talk] sealing cavity in capacitive pressure sensor

Reza,

One thing that you can try is to mix precision glass spheres of the gap size
that you require into your glass frit paste.  Once you apply pressure under
heat, the spheres will become a spacer to limit and maintain the required gap.
You may want to experiment with different size spheres depending on the
precision of the gap required.  You will find a vendor by googling "precision
glass sphere."

I used this technique some time ago making a vacuum display.

Brad Cantos
brad.cantos@holage.com
http://holage.com
LinkedIn: http://www.linkedin.com/in/bradcantos