Problem pquest SNF 2010-03-30 23:00:18: Observed unstable ECR Power

[tdo at snf.stanford.edu]

During my etch (recipe ethrush2), when I optimized the microwave tuning for minimal reverse  power, I observed the reverse power fluctuating between 0 and 20W (back and forth).  The plasma was also flickering.  To stabilize the plasma, I had to detune the reverse power to about 15W.