US Patent 7244625 Plasma processing method and plasma processing device

When plasma ashing is performed on a resist on a wafer, deposit gas containing at least one type of deposit component to be generated from a resist by ashing is added to a gas for plasma generation supplied from a gas supply system for plasma generation, by a deposit gas supply system. By this, the deposit component is actively deposited on the inner surface of a wafer processing chamber so as to protect the inner face of the wafer processing chamber from plasma. As a result, damage of the wafer processing chamber during ashing and particle generation due to the damage are prevented.