Problem sts SNF 2007-03-23 14:37:43: ETCHBACK3 doesn't seem to be cleaning well

[jperez at snf.stanford.edu]

This recipe uses the low frequency, which has a high reflective 
number. Jim Haydon is looking into the problem. When 
etchback3 is completed, please make sure the platen doesn't
show any wafer imprints and has a burnt brown color across 
the platen. And View  port window is clear. If NOT do another 
ETCHBAK3, until the problem has been resolved.