A method for using a film formation apparatus for a semiconductor process includes a first cleaning process of removing by a first cleaning gas a by-product film from an inner surface of a reaction chamber of the film formation apparatus, while supplying the first cleaning gas into the reaction chamber, and setting an interior of the reaction chamber at a first temperature and a first pressure to activate the first cleaning gas. The method further includes a second cleaning process of then removing by a second cleaning gas a contaminant from the inner surface of the reaction chamber, while supplying the second cleaning gas into the reaction chamber, and setting the interior of the reaction chamber at a second temperature and a second pressure to activate the second cleaning gas. The second cleaning gas includes a chlorine-containing gas.