Patent ID: 7530359

Claim:
A cleaning method of a plasma treatment system, for growing an insulating film on a substrate by plasma CVD, then taking out the substrate, and then removing the film deposited inside a chamber by plasma, wherein the plasma treatment system is constructed to cover an inside wall of the chamber down to at least 3 cm from a main surface of a first electrode by an insulator ring, the cleaning method comprising sequential steps of: forming a gap between the first electrode and a second electrode of at least 0.5 cm and a gap of not more than 5 mm between the insulator ring and the second electrode, and performing a first cleaning by generating a first density plasma, lowering the second electrode to a bottom surface of the insulator ring, and performing a second cleaning by generating the first density plasma, and lowering the second electrode to its lowest position lower than the bottom surface of the insulator ring, and performing a third cleaning by generating a second density plasma having a density lower than the first density plasma, the first density plasma and second density plasma being generated by power of a very high frequency.