Awhile ago, I posted a request for information on purchasing a deep Si
etcher. I have finally summarized what people emailed me and what I
learned while purchasing this machine.

  Our need was for a RIE that can etch deep anistropic structures in
many different materials. To do this, we needed a ICP RIE. A deep Si
etcher is simply a ICP RIE that either runs the Bosch Si process or has
a cryogenic chuck. There are four suppliers of 'turn key' ICP RIE
machines: Plasmatherm, STS, Oxford, and Alcatel (they all have web
pages). These system will perform the desired process right out of the
box. This makes these systems expensive. Budgetary quotes range from $
375 K US to $ 550K US. There are other companies (typically small
companies) that will sell you a RIE with a ICP source on top. Axic and
Trionics (spelling ?) are examples. These system will probably need alot
of process development and possibly equipment modification to work
properly. However, the cost is much less. For a university, this is a
option (Also, it sounds like a nice master's thesis).

  From a construction and maintenance point of view, the turnkey ICP RIE
systems (STS, Plasmatherm, Oxford, and Alcatel), appear to be very
similar. The people who e-mailed me and those who I talked to were all
happy with the machines they purchased (regardless of who made it). For
system that were not in use 24 hours/day, the maintenance costs were all
reasonable (about what you would expect for a complex vacuum system),
with the only issue being problems with the turbo pumps). I did not talk
to the people who run these machines in production).

  From a Si etch process point of view there are differences between the
machines. I am not an expert at deep Si etching, but this is my
understanding: Anistropic Si structures can be etched by either the
Bosch process (a patented gas chemistry) or a cryogenic chuck. The Bosch
process allows for very high aspect ratio/deep Si etches, however the
side walls are scalloped. The cryogenic chuck has smoother sidewalls,
but the etch depth and aspect ratio are not as good as the Bosch
process. The Bosch process has been licensed by PlasmaTherm, STS, and
Alcatel And the cryogenic chuck is on the Oxford and Alcatel machines.

Prices:
  These machines are very expensive. For a pure Si etching application,
there are a number of comapnies and universities selling Deep Si etching
services. If we were only going to etch Si, this the route we would have
taken. Since we want to do many materials, we needed to bite the bullet
and spend the money.

  The initial quotes from all the companies should be considered
budgetary, that is a beginning place for negotiation. There is quite a
bit of room for movement on the prices. The prices that various places
paid for their systems is 'known', you need to ask around. From my
experience, the Oxford system was the least expensive and we purchased
the Oxford system.

  Ken Westra
  Manager/Staff Scientist
  MicroFab at the University of Alberta