Idea Re: Zoom(Y) out of range

Luigi Scaccabarozzi scaccag at stanford.edu
Sat Sep 11 14:13:20 PDT 2004


mark and all,
correct, changing the WD won't help (we tried it already...).
In past zoom X and zoom Y used to be both ~ 1.49. At some point, with
no apparent reason, zoom Y became 1.52, which is very close to the limit,
and in some cases can give errors  (when it goes beyond the limit).
IN past the problem fixed by "itself" after a while and the values
became again the usual ones. Now the problem reappears.

Switching to lower mag should avoid the problem although there is
definitely something wrong with the EO board (or something else)
The bad side of decreasing the mag is that you loose in resolution, but
probably this will not affect your write too much.
Another solution is to decrease the writefield (write at 50um, 1200X):
this should also work, but this means having a smaller writefield (higher
stage time, stitching...)

For everybody:
if this happens again before the raith people can take care of it, here is
how to get around the problem:
go on the mag and writefield window (I forgot the exact name), click on
edit and put the values you want (say 570X, 100um), then click on SET. At
this point, when you do align writefield, LEO should go automatically at
the new mag (570X, instead of 600x).
Hope this will help, at least for now.
Gigi

On Sat, 11 Sep 2004, Mark Topinka wrote:

> 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
> >
> >      Geballe Laboratory for Advanced Materials
> >      239 McCullough Building
> >      476 Lomita Mall
> >      Stanford, CA 94305-4045
> >--------------------------------------------------------
>




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