Arcing Problem

Jim McVittie mcvittie at snf.stanford.edu
Thu Mar 28 12:06:23 PST 2002


P5000 Users,

This week we had to replace some expensive parts in the oxide etch
chamber because they
were damaged from arcing. After discussing the problem in AMAT, we
concluded that the
problem was most likely from  running the chamber at too high of a bias
voltage. It was
estimated that the bias voltage may have been as high as 1600V. As you
know, the one does
not directly set the bias voltage in a process recipe. Instead, the bias
is developed from the RF
current with a resulting bias value which depends on the pressure,
power, B field and gas mixture. With a typical power setting of 500 to
600W, the most important parameter determining bias is the pressure. To
avoid arcing in the future, Applied is recommending that we prohibit any
process with pressures below 60 mT. The exception is the breakthrough
step in the Al etch process which uses 30 mT at 300W for 15s to go
through the Al2O3 layer.

We will continue to let users modify the standard etch process on the
P5000, but I need approve all proposed process modifications before
hand.

For your interest the process that lead to the arcing problem was:
O2=20, He=20, Pressure=20mT, Power=600W, B=40G, Time=1000s

    Jim McVittie




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