Problem mrc SNF 2006-05-18 14:38:21: Pressure not stable

[calarrudo at snf.stanford.edu]

I am using the same recipe that I always use Ar = 15.0 sccm,
presurre = 10.0, RF = 100, PV = 600.
Intial pumpdown to base pressure when gate valve fully open  is -.0006 mt, when Ar is turned on the pressure is rising to 8.0 then drops back to (1.2).  I normally bring the pressure up to 
20.0 to ignite the plasma when RF the pressure drops to 10.0 mt when plasma ignites.  The pressure is dropping 
to 3.0 then I have to bring it back up to 10.0 while my wafer is etching.  I need to do some 15 sec and 30 sec etches its taking 
that long to stablize to 10.0 so this won't work for me.  In the 
past the MRC has been very stable with its pressure and I 
have been able to do 30 sec etches but not now.  Because thisis the primary tool that I use all the time I know when it isn't 
work correctly.