Chih-Chieh,

When trying to bond quartz, your options are pretty limited unless you
are using an intermediate layer.  Without such a layer, your only choice
is direct bonding.

To accomplish this, you would first need to do a reverse RCA clean as
follows:

RCA2 (SC-2): HCl (37%): H2O2 (30%):H2O in a volume ratio of 1:1:6 at 70C
for 5 minutes; DI water rinse

RCA1 (SC-1)     NH4OH (29%):H2O2 (30%):H2O in a volume ratio of 1:1:5 at
70C for 5 minutes; DI water rinse

I've actually done these steps a few times myself in the ASU CSSER clean
room; the chemicals should all be available.

Once the clean is done, you would place them into the EVG501 using
separation flags, cycle the chamber to achieve the desired atmosphere
(nitrogen, vacuum, etc.), apply contact at a single point using the
wafer bow function, and then pull the flags out one at a time. This
"pre-bond" would be applied at room temperature.

The key thing here is the smoothness and flatness of your wafers - the
process works best if the surface roughness is very low (<0.5 nm RMS),
but some bonding can still occur up to 2 nm RMS.

Once the pre-bond is done, the wafers would need to be placed in a
furnace at ~1000C for annealing.

If 1000C is not feasible, another option is via plasma activation prior
to the prebond (via an EVG810, for example), which will reduce the
anneal temperature to below 300C.

Best Regards,
Chad Brubaker

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Chih-Chieh Cheng
Sent: Monday, February 27, 2006 2:53 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Anyone ever done bonding for 3" quartz wafer?

Hi, everyone

As title, we are trying to bond two 3" quartz wafer using EVG 501. Do
you
have any comments on it?

Thanks for your time

Chih-Chieh