Patent ID: 7691445

Claim:
A method of using a vertical film formation apparatus for a semiconductor process configured to form a thin film on a plurality of target substrates held at intervals in a vertical direction inside a reaction chamber, the method comprising: removing by a cleaning gas a by-product film deposited on an inner surface of the reaction chamber without the target substrates held therein, while supplying the 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 cleaning gas; and then, chemically planarizing by a planarizing gas consisting essentially of F 2 gas, H 2 gas, and N 2 gas, the inner surface of the reaction chamber without the target substrates held therein, while supplying the planarizing gas into the reaction chamber, and setting the interior of the reaction chamber at a second temperature and a second pressure to activate the planarizing gas, wherein the inner surface of the reaction chamber contains as a main component at least one material selected from the group consisting of quartz and silicon carbide.