raith as imaging tool?
jwc at snf.stanford.edu
Thu Dec 6 12:04:44 PST 2007
Good Afternoon RAITH Users:
We have no policy against using the RAITH as a SEM or metrology
measurement tool. Any qualified User may utilize his or her reservation
session time on the system for any purpose within the tools capability.
The Raith is a full feature metrology and digital imaging system in
addition to being an Electron Beam writer. It is designed to be used for
manual and semi-automated to fully automated image, mask or EBL pattern
inspection and verification. It is also one of the highest resolution
Scanning Electron Microscopes here at Stanford, and possibly the only
tool calibrated to NIST traceable standards that is checked regularly.
As of last Friday the electron beam waist at 10 keV using the 30 um
aperture is less than 2 nm with a gage of 0.3 - 0.5 nm using a prickly
Au on carbon resolution standard. This exceeds the manufacturer's
specification by a factor of Two! (Raith's Factory acceptance spec. is
less than 2 nm at 20 keV and less than 4 nm at 10 keV.) That sample is
mounted on the SEM stud on the Std. Sample Holder feel free to explore
it and use it in your work on the tool.
However you bring to light a important point regarding the Coral
Reservations and the Raith community honoring each others Raith
reservation session times!
My expectation of All Users is this:
If you have a reservation for the current time slot, for example 1 to 6
PM, then this is your time to be on the tool. It is expected that you
would yield the tool to the next user upon their arrival in the lab and
optimally within a15 minute window on either side of the end of the
previous users session. (i.e., 5:45 - 6:15) If the next reserved user
doesn't show up before the current session ends they may extend into the
next reservation time slot -- but must begin to unload their sample when
that next User arrives. However please note we do have a specific
policy for persons whom do not show up for their sessions on time called
'The 16 Minute Rule'. That policy states if at 'Minute 16' after a
reservation on Coral starts and that User has not show up for the
session in the lab, or sent an email to the raith list, and/or posted a
note on the tool that they intend to use the session; they have lost
their reservation as it has expired at 16 minutes after the session
began. Then 'he who is enabled', or the first user to enable the tool on
CORAL, has the session through the end of the reservation time slot. It
is simply upon his or her courtesy to return the tool to the User whom
lost their session, or to the next User reserved on coral, if their
tasking is completed before the session times ends.
It is expected of all Users working on the Raith tool would strive to
work cooperatively together with all other Users and to expedite the
hand-offs between sessions slots at the times indicated on the Coral
Users are reminded that there are _no limits on utilization of the tool
just a limit on the amount of time you can reserve the RAITH tool on
This was decided by the Raith Community in 2006 to allow fair and equal
access to all Users to make a reservation on the tool within a
reasonable amount of time. In my understanding within a 10 to 14 day
horizon. However if you are on the RAITH tool when it is free and you
have enabled on Coral naturally, but do not have a current reservation
on coral, then any User can fill the slot on Coral reservations and that
User can request the person to vacate the tool upon their arrival
SNF Staff and management are also currently seeking solutions to fulfill
the need for High Resolution Scanning Electron Microscopy and metrology
tooling here at the Stanford Nanofabrication Facility:
* We recently had Hitachi High Technologies America Field Service,
formerly Hitachi Instruments, perform a complete Preventative
Maintenance routine on the Hitachi S-4160 Field Emission SEM that
we call /SEM4160. /This tools brightness and resolution are now
close to manufacturers specifications. Users returning to this
tool will rapidly note the improved resolution and imaging
capability when using it. We have also performed adjustments to
the X-Y stage to reduce the stage drift and over travel movement
and added a Quartz PCI Digital Imaging acquisition package to this
system. If you have not been on this tool in some time my
suggestion would be to come back in and try it out, you may find
it suitable for much of your SEM needs.
* For the last year Paul Rissman and I have been engaged with
Hitachi High Technologies America towards identifying and
obtaining a donation of a newer Digital Scanning Electron
Microscope. Thus is to meet the metrology needs of all lab members
working at SNF, but in particular to support the effort on the
ASML stepper. This effort has started slowly, mainly in
discussions with contacts at Hitachi in our personal networks at
conferences and exhibitions, and hope to place as a donation a
newer instrument into SNF sometime in 2008.
During the next Ebeam Town Hall Meeting, to be held in the New Year, we
can open for discussion modifications to reservations and usage policies
on the RAITH tool. I would also encourage all Users to participate in
discussions of this nature on the raith at snf.stanford.edu mail list.
Everyones opinion is valuable to me and to SNF management. Your work and
success are important to all of us here.
Finally I would request of All Users to please engage in a bit more
courtesy and diligent effort when coming on and off the tool to do so
promptly at the end of their reservation's time or when they have
completed tasking early. With the recent hardware and software upgrade
that was donated by RAITH GMBH and RAITH USA this year, and the great
increase in speed and throughput achieved, we now have much more
capacity on the tool than previously. If everyone checked the protocol
files for their write time record, they would know exactly how long it
takes to run their exposures, and this would certainly increase the
opportunity for all users to get more work completed on the tool.
Currently the tool often sits unattended after an exposure ends waiting
for the next User to arrive and start their session. Much opportunity
would be gained if Users worked together more closely. Should we
require Users to be present at the end of an exposure and to unload as
soon as it is completed?
Your opinions and suggestions are invited, please respond to the raith
e-mail list only.
Thank you for your support!
A Raith User wrote:
> Hi James,
> Since when is it considered acceptable to use the Raith as an SEM?
> The other SEM just sits free and unused all the time, whereas I've
> noticed that a lot of people have been sneaking in SEM time on the
> Raith, sometimes between sessions, which delays reserved users while
> they wait for the SEMers sample to unload. Every time I have used the
> Raith in the last month I have had to wait for the previous user for
> at least 15 minutes. I am currently sitting and waiting for some guy
> who thought he'd get in a quick SEM session to unload his sample.
> Sorry for griping, but i think that the Raith wouldn't be so
> overbooked if people would stop using it for imaging.
> user name deleted by JWC.
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