Howdy,

I'm looking for information on Al-Si wafer bonding, and I saw a good
thread here from 2002 about why I don't want to do it, so I was
wondering if there was equally good information here about how to do
it if I had to.

I'm new to wafer bonding, and the papers I've found that mention it
haven't been too informative (although perhaps I haven't found the
right papers). One issue is that the wafer bonding setup I have access
to only goes up to 550C, and for various reasons (including that we'd
eventually like to bond sapphire to Si with an intermediate Al layer
-- my understanding is that the differences in thermal expansion rates
can cause trouble) we'd like to avoid temperatures that high.

We don't need particularly strong bonding -- mostly it just has to
survive (man)handing during the rest of fabrication (which will
involve some lithography and etching). However, the bond or two I've
made so far aren't cutting it (200C, 2.5MPa, 30min, they fail if you
look at them funny). Anyone know what strengths can be achieved at
different temperatures/pressures/times? Any tricks that could make
things go more smoothly? Other advice?

Thanks.
-Leon