Problem stsetch SNF 2009-08-13 10:51:43: bad etch again

Nancy Latta said that a large chunk of wafer was retrieved from the chamber which might be responsible for my previous bad etch. So I tried again. This time, I watched it throughout the etch. Mask erosion occurred quickly and wafer color was dark, which are both abnormal. I had to stop the etch 20 minutes before the normal finish time. This wafer is bad again. I think this machine requires thorough cleaning and checking for leaks.