RAITH STATUS: 05-20-2005 16:36:23: Beam Unstable above 20 kV acceleration voltage...

James Conway jwc at snf.stanford.edu
Fri May 20 17:33:34 PDT 2005


We may not currently be in an optimal operation parameter window for the 
FE-GUN operation at higher acceleration voltages. While emission is good 
and stable at 10 kV; with higher acceleration voltages the Extraction 
Current and Gun vacuum are varying by a large amount and emission 
becomes irregular.  No arcing events or EHT trips have been encountered 
this week. The value for Ext I 'off' to 'on' at 10 kV is 33.5% and 
slowly rising, and for 20 kV much much larger and very irregular in 

To be safe operations are being restricted to all users to below 20 kV.
Please contact me if you have any questions and be sure report all 
problems to CORAL.

Sadly, and certainly not to my satisfaction,  neither RAITH USA nor I 
have been able to influence Zeiss SMT Field Service to come in and make 
adjustments to our E/O board as requested nearly two weeks ago.  These 
were to be the alignments and adjustments we have normally performed 
after running in the system a week or so. Users will see slight shifts 
going from mag range 2 to 3, and when adjusting stigmators for some 
apertures only. These are not large magnitudes and well within the range 
of the E/O card adjustment range.
This leaves me no choice other than to perform these alignments myself 
early next week and/or we must escalate this problem to management level 
at RAITH GmbH and specifically towards Zeiss management in Oberkocken, DE.

Other than just one Email last week there has been no response from 
Zeiss SMT to come in and it has been obvious that calls from both 
entities are, at the moment, simply being ignored.

Thank you for your support!

James W. Conway
Stanford Nanofabrication Facility

-------- Original Message --------
Subject: 	Problem raith SNF 2005-05-20 16:36:23: Beam Unstable above 20 
kV acceleration voltage
Date: 	Fri., 20 May 2005 16:36:23 -0700
From: 	jwc at snf.stanford.edu
To: 	raith-pcs at snf.stanford.edu

Extraction I and Gun pressure vary wildly above 20 kV
CALL James Conway if you have questions over the weekend.

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