raith status from gigi a week ago...
jwc at snf.stanford.edu
Tue Sep 14 11:35:36 PDT 2004
James Conway is back in the office....
The piezo calibrations are still outstanding and likely adjustments may
need to be made to the kinetic mounts to get the standard sample holder
truly flat across its 150 mm range. Note that the specs for the
standard sample holder are not as tight as the Electrostatic chuck (ESC)
and the scratches on the surface of the Std. sample holder or resist on
the back of the chip may also negatively affect your results.
The range of the piezo post are only 105 um and currently we are not
able to complete the leveling routines to obtain a leveled wafer on the
ESC despite several efforts to perform the calibration. (Out of range
errors...mechanical adjustments must be performed....)
NOTE: ALWAYS START OUT WITH CENTER PIEZO'S AFTER THE WARM UP ROUTINE.
This setting was changed or lost after the recent RAITH150.vbd
modification that came back from RAITH and I have been unable to find
the init setting call in either the RAITH150.vbd or my User.vbd so I can
get it to start as a default with Piezo's centered upon loading the system.
I continue to evaluate the 'Zoom U. or V. exceeds range allowed' issues
in the Align Writefield, but clearly there was as significant change to
the column or E/O board set up during the period of down time we
experienced in August. It is my understanding that this can be improved
with the quadrazitung or orthogonality adjustment calibration of the E/O
section of the system.
It was expected that ZEISS would return for final calibrations and
adjustments after we ran the system in for a week, so I will follow up
with them later this week after I get some more time on the system this
week. RAITH was not able to complete the piezo leveling adjustments
during their last visit here as we ran out of time working on chiller
Will post to this listing more information as I collect the data.
Luigi Scaccabarozzi wrote:
>Hi ... (sorry, I'm not sure how to spell your name),
>I got your voice mail. I've been away the past two days, however this is
>what I can tell you: I just started an overnight write, everything seemed
>ok (beam quality, spot size, align writefield...) except one detail:
>the V zoom factor for 100 um WF, 600X, 5mm WD, 10um aperture, 10keV was
>1.52 whereas the U zoom factor was 1.49.
>I remember in past the two numbers were about the same (~1.49). A few
>weeks ago we had the problem of V zoom factor exceeding the range (which,
>BTW, is close to 1.52), and we could not write at 600x, but only at, say
>570X. After a while the problem misteriously disappeared and zoom V factor
>got back to normal values (~1.49).
>This time the V factor didn't exceed the limit, so I started the write
>Another comment is about the current: at 10 keV, 10um , after cleaning and
>bake I would expect a current of at least 0.025nA, whereas I measured only
>0.0175 nA... has the column already got that bad?
>Otherwise I didn't hear of any complain from other users.
>I will develop tomorrow morning and I'll be able to tell you more.
>I haev also one question about the piezos: I'm using small pieces (~ 1x 2
>cm) and trying to write on most of that area. I use the standard clips and
>I notice that it's hard to keep the focus over such area. Can I use the
>piezos for this purpose, or the piece is too small?
>what's the standard position of the piezos, for which the stage itself is
>flat? Should I "center the piezos" at the beginning of the
>session or leave them as they are after the warm up?
>I'll write/call you tomorrow after developing tonight's sample.
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