Hi Bing, Pink plasma indicates N2 in the systems (ie air) - most likely case is that you have a leak as you mention. Best course of action is to use a leak checker or failing that a rate of rise check each time you blank off a potential source. Good luck. Andy McQuarrie Surface Technology Systems Message text written by General MEMS discussion > We have a BOC Edwards Auto 500 Sputtering system. The normal glow plasma color was light green, but it is pink. I still can deposit Au films with lower deposition rate but not Si, instead I got transparent films. I suspect the chamber has leakage and the Si could be oxidized. Does anybody has the same experience? Please advice. Bing <