Mufei,

The surface and interface between pads might have fracture after ultrasonic
bonding. The excessively deformed metals might change contact resistance
between pads due to excessive bond force.

Thank you and best regards,

 JTD

-----Original Message-----
From: [email protected] On Behalf Of mufei gong
Sent: Monday, March 22, 2010 8:38 AM
To: [email protected]
Subject: [mems-talk] wire bonder ruined my device

Dear all,

When I use an west bond 7400A Aluminum ultrasonic wirebonder , before I did
the wirebonding, the resistance between the two metal pads was >10 Mohm, but
after I did the wire bonding, the resistance dropped to a few hundred ohm to
a few kohm. the other ends of the two metal pads are separated by a 150 nm
trench of GaAs. This happened to 3 of my devices, and now I only have one
left...

does anyone know what might be the cause of this?