No restrictions on acceleration voltage: OPERATIONS APPROVED TO 25 kV for all users. + NEW E?O BOARD

[James Conway]

Greetings Raith Users:

A new replacement for our Electron Optics board was installed yesterday 
which was aligned and tested in the evening.  I am running a long 
exposure this afternoon and I expect the system should pass 
qualification as I am observing good performance.  Smallest shot dot 
this morning was on the order of 7 -8 nm ! Beam drift was at 10 nm/min. 
Resolution of SEM imaging is excellent.

OPERATIONS APPROVED TO 25 kV for all users:

I would like to request that you give the system additional time to pump 
down and stabilize before starting up the EHT bringing the acceleration 
voltage up after loading. I was unable to reproduce the EHT arcing 
events encountered two weekends ago by any means employed. We have now 
operated  at 20, 25, and 30 kV acceleration voltages for many hours 
without problems.
The 20 kV writes from last week look very nice albeit we are still 
suffering from decided column scatter issues and these effects are more 
pronounced in the exposure artifacts at higher acceleration voltages 
particularly for single pixel lines and dot shots.

Tips and Tricks:
You may find it easier to set up your UVW coordinate system and locate 
your targets for overlay at 10 kV. Then move up to the higher 
accelerations voltage desired to set up the column once again, perform 
your write field alignments, reacquire your saved position of targets 
for overlay to confirm their position, and only then perform your 
writing task.

Users are requested to report at problems encountered to this list and 
make a comment on CORAL.

We continue to work closely with both RAITH organizations and ZEISS SMT 
with urgency. All parties hope to have a plan of  action to address this 
problem in the coming week. Likely we will be rebuilding sections of the 
SEM column and repeat the PM routine as is necessary to effect repairs 
to the system.

Thank you for your support!

James Conway


-------- Original Message --------
Subject: 	Re: Problem raith SNF 2005-03-11 14:20:07: operations 
restricted to 10 kV through the weekend.
Date: 	Thu, 17 Mar 2005 09:27:28 -0800
From: 	jwc at snf.stanford.edu
To: 	raith-pcs at snf.stanford.edu



System tested repeatedly to 20, 25, and 30 kV acceleration voltages and no EHT trips were encountered.
OPERATIONS APPROVED TO 25 kV for all users.
JWC 

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