Lampoly particles

[Mary Tang]

Hi all --

We've just learned from the more experienced Berkeley folk that the 
black particles observed by a couple of people this week are actually 
redeposited buildup from extensive use of the HBr-only recipe, without 
alternating with the clean recipe.  Since the clean has been faulting 
during the etch, we have not been able to run the full clean recipe.

I've just put the system down.  Apologies for the inconvenience, but we 
don't want to risk contaminating people's wafers.  The system is 
undergoing chamber purge now and the chamber will be cleaned first thing 
Monday (thanks Elmer).  We will also work on troubleshooting the clean 
recipe failure, which appears it might be an RF problem which is 
manifested as a pressure control/turbo failure. 

We would greatly appreciate it if lampoly users could report process 
problems as they are observed.  If you have sample wafers or photos of 
the black particles, they would be much appreciated for our defect library.

Thanks,

Mary

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