In my experience, when a Cr/Au film is exposed to high temperature, the
Cr will be absorbed into the Au and adhesion will be lost.

Could it be that there is some variation in the temperature of your spot
weld, where in some cases, the Cr absorption temperature is reached and
sometimes it is not?  This would explain why sometimes your film is
pulled off and sometimes it is not.

Dan Ruiz
MEMS Process Engineer
Honeywell International
15001 NE 36th street
Redmond, WA  98073-9701
Phone - (425) 376-2167
dan.ruiz@honeywell.com

________________________________

From: mems-talk-bounces+dan.ruiz=3Dhoneywell.com@memsnet.org on behalf =
of ???
Sent: Wed 8/31/11 12:24 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Tolerance of CrAu film to high temperature shock?



Hi All,

We sputtered CrAu metal films onto the surface of a silicon dioxide
layer which is on the top side of silicon wafers.  The Au metal film was
then thickened by electroplating to about 3 microns.
We did the adhesion test by spot-wielding Au tape and pulling the Au
tape. Sometimes the film under the wield spot were pulled off, sometimes
not. While doing the Thermosonic tape bonding and pulling test, it shows
that the film adhesion is good.

It seems that some batch of CrAu films couldn't bear temperature shock
by spot-wielding.
How could we improve the tolerance of CrAu films to High temperature
shock?

Has anyone had similar experience?

Is it suitable to spot-wield Au tape onto silicon dice?

Thanks!