Problem stsetch2 SNF 2010-03-29 16:02:47: Etch rate is not stable

[jjeong1 at snf.stanford.edu]

I ran two wafers to measure Si etch rate. For the first wafer, the etch rate was 3.5um/min, but it dropped to 1.8um/min for the second one. The second one was run right after the first one. 
(Two weeks ago, it was ~7.4um/min and the wafer-to-wafer etch rate was quite stable.)