Idea Re: Zoom(Y) out of range

[Mark Topinka]

Hi John, Raith folks-
      My two cents: I doubt simply changing the working distance will fix 
it, because the Leo system will automatically compensate for any changes in 
working distance by offsetting changes in the Y and X deflection coil 
constants, resulting in roughly the same Zoom(Y) and Zoom(X).  Inst\ead, 
use what Gigi suggested- it worked last time (ie. go to lower mag for a 100 
micron writefield- this needs to be set somewhere, maybe in the writefield 
dialog box?  maybe somewhere deep in the menus- I can't remember).  The 
basic problem is that for some reason the Raith PG + Leo system is not 
physically able to bend the electron beam by (0.5 * 100 micron =) 50 
microns at what it calls "600x", regardless of working distance.  But it 
can at "590X" or, to be even safer, at "580X" or "570X".   I don't see any 
problems with just going with this solution (use "570X" for a 100 micron 
writefield)- I can't think of a reason it would degrade anybody's 
results  (maybe somebody else can?).   Eventually we can get the 
calibration on the EO board fixed, but until then I don't see a reason for 
why this won't work perfectly well.    -Mark

At 09:56 AM 9/11/2004 -0700, cumings at stanford.edu wrote:
>Hey all,
>
>I had the same error last week, but I didn't have it during my write this 
>week.  Perhaps the (Y) gain on the new E/O board is just a little bit 
>lower than on the previous board, requiring higher voltage output from the 
>elphy.  I did notice that the (Y) zoom factor was about 1.52 during 
>successful WF alignments.  I remember it being more like 1.48 in the past.
>
>My idea: could this depend on the working distance?  Maybe if you get this 
>error again, try reducing the working distance, perhaps 50-100 micron or 
>so?  Just a thought.
>
>I'm not cc'ing Raith on this one - if one of the Raith champions wants to 
>pass my ideas on to them, feel free.
>
>-John
>
>-----Original Message-----
>Sent: Friday 9/10/2004 10:37:14 PM
>Subject: Re: Zoom(Y) out of range
>
> >Hi Dong-Woon,
> >I guess you are writing at 600X, 100um field. What's the value of zoom Y?
> >the Y zoom factor must be < ~1.52. you may set 590X, 100um, or decrease
> >more the mag (570 or 550), that should work, but this is not normal and
> >its the same problem we had in past. Cole or Joe, can you help with this?
> >I guess it's again a problem with the calibration of the EO board...
> >Thanks
> >Gigi
> >
> >On Fri, 10 Sep 2004, Dong-Woon Shin wrote:
> >
> >>
> >> Hello.
> >>
> >> I am having continuous error in write field alignment - "Zoom(Y) out of
> >> range: please readjust SEM stage and ELPHY"  Only down to 10 um field 
> is OK.
> >> What does the message mean and what am I supposed to do?
> >>
> >> - DW
> >>
> >> PS. Also I met "access violation err. address 4006A668 in
> >> module "vcl50.bpl" reads of address 00000060"
> >>
> >
>
>
>--------------------------------------------------------
>      John Cumings
>      cumings at stanford.edu
>      Postdoctoral Scholar
>      Physics Department
>      Stanford University
>
>      office (650) 725-1025
>      lab (650) 725-2047
>      fax (650) 724-3681
>
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