Current Lot of ESPACER has been tested this week and is working fine.
jwc at snf.stanford.edu
Fri Jul 31 09:48:01 PDT 2009
Greetings Ebeam and RAITH Communities:
I have had several users working with me through the course of the last
few weeks that had reported either problems in charge compensation or
poor contrast when imaging SOI and LTO Oxides over their target features
during Ebeam sessions. All of these persons were attempting overlay
target acquisition for second layer EBL writing. There had been
concerns due to the fact that several weeks ago the material was left
out and allowed to warm to room temperature over the weekend.
This week Jamal Moline, Kyeongran Yoo, and I tested the current batch
of ESPACER 300Z and found no problems with the solution. We tried 3000
rpm for 40 seconds with no post bake resulting in a sub-50 nm thin
film. I also worked with a Quartz substrate spinning at 5000 rpm/ 40
seconds and a 90 second 90 degree C bake. This film was very thin,
maybe a bit too thin on the extreme edges, and did not cover all mesa
and raised target features on the substrate. However in imaging and EBL
writing I encountered normal contrast and only the slightest of sample
surface charge up during high magnification imaging.
Please be frugal with this very expensive engineering material. Please
dispense from syringes only and never pour directly from the bottle onto
your wafer. Currently I am using 15 drops per 100 mm wafer and obtain
complete coverage with suitable uniformity. Finally please make a
personal effort to maintain this material at refrigerator temperatures
(~5 degrees C.)
Thank You for your interest in Ebeam Technologies here at Stanford
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