To supply a cleaning method that removes a deposited film produced during dry etching and hydrophilically process an etched surface in a process that discharges etching gas and deposited gas simultaneously or alternately.

A deposited film is considered to be made hydrophilic by introducing O into its polymer to make H2O bind with hydrogen. The ways to introduce O2 into a polymer film are to thermally oxidize silicon, to oxidize film surfaces using low-pressure and high-density plasma, to oxidize film surfaces by exposing boards to high-temperature steam, to emit UV (ultraviolet) or EB (electron [electronic] beam), to have CVD in normal or reduced pressure or with plasma, and to catalytically react peracid, each of which can resolve and remove polymer films and make the etched surfaces hydrophilic.