We offer deep rie service as you described but I would need to understand
your specifications better to respond. What makes our system unique compared
to systems that use the Bosch process are as follows:

We are able to etch anisotropically to 100 microns depth with smooth
sidewalls. Since we use a single step process we don't have scalloping due to
the deposition/etch cycles of the Bosch.

The other advantage which would be of interest to your process needs is the
fact that for features sized from 2 microns to 50 microns we can control the
rie lag to around 5% across a 100mm wafer. This coupled with a very
sophisticated endpoint system allows us to call endpoint through the silicon
and keep our overetch to around 10% to account for nonuniformity. We have
been told from other customers that a 50% overetch might be required to do
the same using the Bosch process. This amount of overetch would account for
the footing along the interface between the silicon and the soi wafer.

I would need additional information such as how deep you want to etch, how
thick your soi wafer is so if you are interested you can contact me directly

Bob Henderson
Process Integration,LLC
Phone: 480-558-1156
email: bobh@processintegrationllc.com