PURPOSE: A method for cleaning a process chamber is provided to increase the cleaning efficiency of a transition metal compound by successively supplying chlorine based cleaning gas and fluorine based cleaning gas. CONSTITUTION: A process chamber including an inner wall is prepared. A thin film including aluminum is formed on the inner wall. Chlorine based cleaning gas is supplied to the process chamber. The residue is formed by etching the aluminum of the thin film with the chlorine based cleaning gas. The fluorine based cleaning gas is supplied to the process chamber. The residue is etched by the fluorine based cleaning gas.
