We study for the effects of additional gas such as oxygen (O-2) and hydrogen (H-2) into SF6. When H-2 gas was added to SF6, surface fluoride atomic concentration and surface roughness were lower than the other additional gases. Surface fluoride atomic concentration under this experiment was reduced from 28 at % to 6 at % by the H-2 addition. In post-processing, the fluoride atomic concentration was succeeded in a large reduction by processing H-2, O-2 plasma and high temperature hydrogen annealing. In hydrogen annealing, surface fluoride atomic concentration could be suppressed to less than 3 at %. This is new result succeeded in reduction of surface fluoride species greatly by hydrogen processing.