US Patent 6969308 Method and apparatus for chemical and mechanical polishing

A polishing device is hermetically accommodated in a chamber containing an atmosphere having a composition different from the ambient air, so that the atmosphere around the polishing device is altered into the composition different from the ambient air, and voltage is applied between a wafer and a polishing pad to polish the wafer with an electrolytic effect. The polishing device has the atmosphere containing extremely less oxygen, preventing a surface of the wafer from oxidation and thereby providing a constant polishing rate.