Hello all,

I see great variablity in etch rate of silicon with RIE CF4:O2 etch.

At one point I see etch rate of >1um/min, at other <0.1um/min. This is at same
proces parameter setting (1:12 O2:CF4 ratio, 0.2T, 500W).

Can anyone comment on what might casue such wide variability in etch rate at
nominally constant process parameters?

Thanks in advance,
K.C.