It was reported that the SBT plasma cleaner had some problems on June 24. No plasma was generated. After checking, the RF cable was found broken. A new cable was ordered.
Besides the cable problem, the vacuum was too low. SBT engineer is going to check the vacuum system with a new pump tomorrow.
The plasma cleaner was taken to SBT. Vacuum leakage was found at the needle valves. The damaged valves have been replaced. The cleaner was back yesterday. I have tested it. It works well now. Please note that the needle valve can be damaged easily. I have set them to the right position. You do not need change them. Here is the revised procedure for gas needle valve: after the chamber pressure is dropped to 100, turn on one gas (either O or Ar). Wait till the pressure is stable at about 200 (+-10). It takes about a couple minutes. Then start to generate plasma as described in the SOP.
Even with a replacement pump, the machine could not reach the desired low vacuum. SBT Engineer has taken the Plasma Cleaner to the factory for repairs. They will check all ports and valves for leakage. Expect repairs to take 1 week (updates to follow)