Seeing High Oxide Etch Rates Need Old Rates

Jim McVittie mcvittie at cis.Stanford.EDU
Thu Apr 12 18:11:44 PDT 2001


Lam Users,

We are experiencing higher oxide etch rates than normal for both the
HBr/Cl2/O2-He and HBr/O2-He processes. My first thought was that we are
see a fluorine (F) memory affect where F comes off the chamber walls for
some time after the plasma clean. However, the oxide etch rate is coming
down a lot slower than I expected after a plasma clean that I did this
morning. After well over an hour of seasoning with HBr/Cl2/O2-He and
HBr/O2-He processes, Theresa Kramer still had a problem stopping on a 90 A
of oxide under poly for a process that use to work with no problems. This
morning when I was doing my tests, the oxide etch rate after about 30 min
of seasoning was around 110 A/min during the main etch step for the std
poly etch process (#1). When I orginially set up the Lam, the etch rate
for this step was only 35 A /min. If you have measured any oxide etch
rates on the Lam during the last year or so, can you please rates and
process used. 

	Thanks,		Jim 	
--------------------------------------------------------------
James P. McVittie	                Senior Research Scientist
Allen Center for Integrated Systems     jmcvittie at stanford.edu
Stanford University             	Tel: (650) 725-3640	
Rm. 336, 330 Serra Mall			Fax: (650) 723-4659
Stanford, CA 94305-4075	




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