Clean Si fusion Bonding

Mary Tang mtang at
Wed Jan 7 12:52:31 PST 2004

Hi Tariq --

I'm sure Mahnaz and Colby will have more insight on this -- but I don't
believe we have the capability to do Si fusion bonding in a vacuum
environment.  Pre-bonding (i.e., just touching two wafer together) can be done
in the vacuum environment of the bonder, but I really don't know if you can
simply take the wafers out and place them in a furnace and maintain vacuum
(have you done this?  I don't have Si-Si bonding experience -- and when I've
done glass-Si vacuum bonding, it's been in a vacuum furnace...)  How long does
the thermal part of your Si-Si fusion bond process take?

Also, grinding/polishing are dirty processes and the STS is considered a clean
system.  I believe there are certain required clean protocols following
grinding/polishing which may allow something to return to some clean systems
in the lab (Jim, didn't you work this out already?).


thaniff at wrote:

> Dear Specmat members,
> I would like to do some si fusion bonding in a vacuum ambient.
> The general process outline is:
> 1. Etch Cavity inta a bulk or SOI wafer.
> 2. Perfom pre bond clean Sulfuric, RCA1, and RCA2.
> 3. Bond to another  bulk or SOI wafer in a vacuum environment.
> 4. Thin down (grind and polish) the non-cavity side of the wafer.
> 5. Pattern and etch (in STS) the non cavity side of the wafer.
> I'd like to know what the current options are for this process in the SNF.
> Best Regards,
> -Tariq

Mary X. Tang, Ph.D.
National Nanofabrication Users' Network
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
mtang at

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