Hi Arie,

Anodic bonding is out.  Aluminum tends to break down in a anodic bond and
the high voltage can damage your CMOS device.

Eutectic is out if you use Au because it will defuse in to the device.

I would suggest adhesive or glass frit.  With Glass frit you will be
looking at a bond temp of 350-500C depending on the type of frit.
Adhesive will be a much lower temp but it is not hermetic.

Frit is usually applied by screen printing it on.  After printing the frit
wafer goes to a first fire.  After this baking process the frit is now in
a solid glass state and can be handled.  Next the wafers are aligned and
then bonded with temps ranging from 350 to 500C while applying force.  You
can bond under vacuum, atmosphere or over pressure depending on your
needs.

Adhesive can be patterned or the entire wafer can be coated.

Feel free to contact me if you have any questions,
Brad