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 University             	Tel: (650) 725-3640	
Rm. 336, 330 Serra Mall			Fax: (650) 723-4659
Stanford, CA 94305-4075	

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