Comment raith SNF 2005-03-09 17:35:30: NO OPERATIONS ABOVE 20 kV]

James Conway jwc at
Thu Mar 10 09:52:44 PST 2005

RAITH Magnification Range Three Update:
There exist a fault in the Magnification Range 3 amplifier on the 
Electron Optics board (E/O ) due to damage during last weeks EHT trip.  
We cannot make suitable adjustments to this amplifier's range of control 
to allow the SEM image at mag. range three to be centered and aligned as 
it should be with respect to the lower mag. ranges 1 and 2 SEM images. 

Monday I attempted to make the adjustments myself and I could not bring 
the image into the centered range and perform the alignment.  Zeiss SMT 
Field Service expert Mike Santomango visited SNF yesterday and we did 
our best to correct this but the E/O card is damaged and we cannot 
repair it on site.  Zeiss is working to locate a suitable model of this 
E/O board for our system here in the USA. I expect to hear from them 
today on the status. Otherwise we may have to wait until the E/O board 
is built up and shipped from Oberkocken, Germany. I am hoping we can get 
a new E/O board in and adjusted by this weekend.

In Brief:  While the mag range 3 SEM image is not centered with respect 
to the centered SEM images from Mag. Range 1 and 2 it still functions at 
high magnification.  Shifts as much as -100 to - 400 um U axis can be 
expected. Generally your high mag contamination dot  will be located 
well to the 'West' in your Mag range 2 field of view.  I normally burn a 
dot and let it scan in the reduced raster mode for about 15 seconds. 
Then reduce magnification to high end of Mag range 2, locate and center 
in the cross hairs the small box and perform my first iteration of the 
Align Write Field procedure on this feature.   Further reiterations of 
the process will locate your shot dot as you normally do.

You can view your MAG range easily using LEO :: [View] [SEM Status] 
{select Mag range from list in second tab if necessary} {First Tab to 
view status panel}
For your information at 5 mm Working Distance:
Mag Range 1 is 32 to ~ 480 X mag.
Mag Range 2 is ~ 480 X - ~ 13 kX
Mag Range 3 is above that. 
You can hear the relays click quietly as you and down scan up in the 
mag. ranges too!
Different working distances will result in different values of mag. at 
the thresholds for each range.

In performing your write field alignment employ this workaround that I 
posted Tuesday afternoon and you will be fine:

Thank you for your support!

James Conway

Ilya Fushman wrote:

> So is the magnification error fixed?
> -ilya
>     ----- Original Message -----
>     From: James Conway <mailto:jwc at>
>     To: raith at <mailto:raith at>
>     Sent: Wednesday, March 09, 2005 6:23 PM
>     Subject: [Fwd: Comment raith SNF 2005-03-09 17:35:30: NO
>     System tested to 30 kV without any EHT trips...
>     Users can now return to up to, but not to exceed, 20 kV operations.
>     Please start at 10 kV allow system to stabilize for 20 minutes
>     then continue upwards if desired.
>     Please all acceleration voltage changes are to be made from the
>     RAITH side column navigator as normal.
>     Problems -- please immediately call James Conway on my cell.
>     JWC 03092005: 18:23:00
>     -------- Original Message --------
>     Subject: 	Comment raith SNF 2005-03-09 17:35:30: NO OPERATIONS
>     ABOVE 20 kV
>     Date: 	Wed, 9 Mar 2005 17:35:30 -0800
>     From: 	jwc at
>     To: 	raith-pcs at
>Today I tested the system ramping from 10, 15, 20, 22, 25, 27, 28 for ten minutes each and allowed to soak at 28 kV for ~ 30 minutes.  Then ramped to 30 kV.  No EHT TRIPS ENCOUNTERED.  30 kV OPERATION WAS SLIGHTLY UNSTABLE IN EMISSION AND WITH SLIGHT ELEVATED VACUUM LEVELS. (GUN 1.8E-009 mbar, 1.3E-009 Torr.)  
>James Conway 03092005:17:33:00
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