Problem lampoly SNF 2010-10-28 17:00:49: RF unstable

[mtang at snf.stanford.edu]

See Jim McVittie's comments on 12/10/10.  Also, it appears that HBr-only recipes are inherently unstable in the first 10-20 seconds after the plasma strikes.  Jim suggests that this is why industry does not run HBr-only recipes despite greater selectivity.  This can be stabilized by running a brief (10-20) seconds of the standard Cl2/HBr main etch recipe followed by HBr-only.  So, you may want to modify your HBr-only recipes accordingly.