Make sure to use EBR!!!

[Mary Tang]

Dear Pquest users:

There has been a rash of stuck wafers in the system.  There is some 
suspicion that this may be due to trace amounts of resist that get stuck 
on the wafer clamp fingers when they press down on the wafer during 
processing.  Then that wafer -- or a subsequent wafer -- can get stuck 
to the clamp fingers.  Since there seems to be an increase in the number 
of people doing hot chuck processing, we suspect that this may cause the 
resist to get soft and sticky, possibly resulting in more stuck wafers.

Please make sure to use 5 mm EBR (Edge Bead Removal) on your wafers.  
Remember, you should select this option on the SVGCoat track program.  
Do not skip the EBR process.   Do not use the 2 mm EBR (the clamp 
fingers will overlap.)  If you have a special need for no-EBR 
processing, make sure to do this on days where we have maintenance 
coverage to rescue your wafer.  (It would also be courteous to let Elmer 
or Mike know in advance, as well.)

Thanks for your attention --

Team Etch

-- 
Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
Paul G. Allen Room 136, Mail Code 4070
Stanford, CA  94305
(650)723-9980
mtang at stanford.edu
http://snf.stanford.edu