There are a number of commercial aligners that can align front and back
to within submicron accuracy.  All you need to do is to locate a company
that has one.  Most of the aligners I know off that can do this are
contact aligners, if contact alignment is acceptable you should have no
problems.  If you have any problems contact me I know most of the
companies that manufacture these aligners.

Bill Moffat

________________________________

From: mems-talk-bounces@memsnet.org on behalf of Andrea Mazzolari
Sent: Sun 1/18/2009 2:37 AM
To: General MEMS discussion
Subject: [mems-talk] front back photolitography


Hello all,
i need to perform front and back photolitography.

On each side of a 4'' silicon wafer i need to realize geometries of size
10um. Geometries on the opposite wafer faces must be aligned with the =
best
possible accuracy.
Here we don't have the possibility to realize front-back photolitography
and so i plan to ask to some company to do the job for me.

Which is the best precision accuracy which can be obtained on the market

Best regards,
Andrea