Plasma treatment method and manufacturing method of semiconductor device

A dry cleaning method for use in a plasma etching apparatus for etching using a plasma of a plurality of gases, comprising the steps of:

• performing a first cleaning treatment using a plasma of a first cleaning gas, to remove reactive product materials containing therein at least one residual etched material created during said etching and attached to inner walls of the apparatus and/or internal components of said apparatus;
• and
• performing a second cleaning treatment using a plasma of a second cleaning gas, to remove chemical components which are reaction products of a reaction between (a) residual etched material attached to the inner walls of the apparatus and/or to the internal components thereof and (b) the first cleaning gas, said second cleaning gas containing therein a material that forms bonds with constituent elements of said chemical components, wherein said bonds have a greater bond energy than that of bonds within said reaction products of the reaction between said residual etched material and said first cleaning gas.