Comment sts SNF 2008-02-06 16:53:56: 2 rf errors on clean cycle

[jperez at snf.stanford.edu]

We need more information on when and if it was a back to 
back RF error. User after this clean put system in clean after
4.1um of oxide deposition and NO ETCHBAK3 error.
I ran a ETCHBAK1 right after without any errors.
Both these recipes were modified in step "Platen Cln 1,2,3"