Daniela,

The fact that you refer to the bonder as an AB1 tells me that this bonder is
pretty old. Does this bonder have double-sided heating capability? Its possible
that the two substrates are at different temperatures during the bond, and this
causes bow upon cool-down.

In general, anodic bonding should be able to work down to 300ºC.

Best Regards,
Chad Brubaker

EV Group
invent * innovate * implement
Senior Process Technology Engineer - Direct: +1 (480) 305 2414, Main: +1 (480)
305 2400 Fax: +1 (480) 305 2401
Cell: +1 (602) 321 6071
E-Mail: C.Brubaker@EVGroup.com, Web: www.EVGroup.com


-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On
Behalf Of Daniela Kögler
Sent: Monday, November 03, 2008 9:05 AM
To: 'General MEMS discussion'
Subject: [mems-talk] Anodic bonding

Dear all,

I have to perform an anodic bond between a Borofloat and a Si Wafer. The
bonding is successful; unfortunately the bow of the package after the
bonding is very high.

I work with a Bonder from the EV Group - AB1 (EVG501).
My parameters are:

Heating 30 min
Bonding 5 min 1000V
Cooling to 150 °C

I tried the temperatures 430 °C and 360 °C.
At 430°C the bow is 225 um, at 360°C the bow is still 200 um.
Can I reduce the bonding temperature with the borofloat wafer to 300°C?

All kinds of suggestions to reduce the bow will be highly appreciated!

Best regards
Daniela
University of Applied Science Esslingen