Raith is coming back up. Specific limits of operations apply through noon tomorrow. README!!!

James Conway jwc at snf.stanford.edu
Thu Feb 19 16:48:18 PST 2004


Hello Raith Users:

The PM has been completed. We just finished adjustments and alignments 
and LEO will return tomorrow to perform a final checkout with me and do 
additional alignments.

The system is coming back up and on line for users WITH THE FOLLOWING 
RESTRICTIONS through noon Friday:

   1. The FE-GUN is NOT to be run higher than 10 keV -- whatsoever.
      We have just brought up the new tip and it is being run in.  We
      have optimized the emission and it is set at the factory test bed
      conditions. Emission is remarkably higher than when we replaced
      the apertures last April! :-)
      This is a somewhat fragile state and the run in will allow the tip
      to gently burn off any asperities on the tip surface and form a
      nice emissive surface by allowing the ZrO coating to form a
      uniform film over the tip's surface.

   2. All resist and materials placed into the system must be softbaked
      at temperture greater than 150 degrees Celsius.
      Several users have had variances from me to use samples that had
      been baked at  90, 125, and 140 degrees Celsius. Those variances
      have been hereby revoked and you will have to see me about how to
      vacuum bake your samples.

      Why:  I noted from data in the logbook that the problems with beam
      instability occurred after users using lower bake temperatures on
      their resist have been on the system. This was also evidenced by
      the very rapid decrease in beam current for specific apertures
      these users had been using. Likely the materials were still
      out-gassing solvents and this added to the hydrocarbon load on the
      system.   Now that we have a new clean column we wish to maintain
      cleanliness of the column and develop appropriate methods to
      ensure only fully cured resist and materials are introduced into
      the system.  We have a vacuum bake oven that we can bring on-line
      for your use.

   3. Until the return of LEO tomorrow we wish to idle the system with
      the EHT ON and the acceleration voltage set to 1 keV.  After your
      run and unload you can logon the LEO and raith as user: test_user
      - passwd: test  and set the gun to 1 keV.  The beam should be left
      unblanked and let it expose onto the stage anywhere off a sample.

      Leo will perform additional fine tuning of the mag amplifiers and
      recheck all stigmator centering functions and together we will to
      the final checkout tomorrow.

   4. Gloves On for everything you touch going into the system -- of course.

   5. Users are requested to report all errors encountered from either
      the RAITH SW or the windows OS.


      I will continue efforts to qualify the system this evening and
      tomorrow. So far the system looks really nice and 'bright'
      compared to before.  30 um aperture = 0.238 nA  20 um aperture =
      0.117 nA.  At 10 keV, 13 mm WD, I resolved a 2.5 nm space on a Au
      on carbon resolution sample.  This is superb and we all should
      strive to maintain cleanliness of our samples and everything we
      introduce into the RAITH system.  All it takes is a fingerprint or
      some uncured resist and we will loose this nice resolution.


This should get us all off to a great start and I look forward to 
hearing about some nice write results in coming weeks.

Thank you for your support!

James Conway


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