Hello Ankita,

Depending on the size of your chip, you may need a "Flip Chip Bonder".  There
can be slip and warping effects - especially if your die are on the order of 0.5
- 1 cm on an edge.

Would be interested in knowing about your Au-Au pad size etc, as we are trying
to do some work in Cu based bonding, and we are always looking for alternatives.

Good Luck!

John


________________________________
From: Ankita Verma 
To: mems-talk@memsnet.org
Sent: Monday, January 16, 2012 10:42 AM
Subject: [mems-talk] Au-Au thermo-compression wafer bonding

Hi Everyone,

I would like to ask for some help regarding wafer bonding using Au-Au thin
films.

I have read many papers and know that plasma pretreatment will help in
bonding wafers at lower temperatures (around 200 C). Though what my problem
is that most of the papers that I have read state that the amount of
pressure they used to bond these wafers using Au films was around 1-10MPa.
This does not make sense for me as I do not have a flip chip bonder, and I
am trying to bond wafers by just applying a weight on top of 2 wafers and
then anneal them in a lab oven at 200 C.

1MPa = 145psi. For a 4 inch wafer it comes to 1822 pounds of weight
required to bond them. This seems to be a lot of weight. I cannot bring so
much weight to bond the wafers. Can anyone suggest a better way to try
bonding the wafers?

How can I try doing this experiment without having a flip chip bonder?
Please help!!

--
Best Regards
Ankita Verma