If the bond force is too high you might have cracked the oxide below the pads.

Shay


-----Original Message-----
From: [email protected] On Behalf Of mufei gong
Sent: Monday, March 22, 2010 5:38 PM
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?