Cleaning method, processing apparatus, and storage medium

Deposits such as particles deposited on a surface of a target object can be easily removed while suppressing damage to the target object such as destruction of pattern formed on the surface of the target object or film roughness on the surface of the target object. In a pre-treatment, vapor of a hydrogen fluoride is supplied to a wafer W to dissolve a natural oxide film 11, so that a deposit 10 attached to a surface of the natural oxide film 11 is slightly separated from a surface of the wafer W. A carbon dioxide gas that does not react with an underlying film 12 is supplied to a processing gas atmosphere where the wafer W is placed, so that a gas cluster of the carbon dioxide gas is generated. Then, the gas cluster in a non-ionized state is irradiated toward the wafer W to remove the deposit 10.