Patent ID: 8277560

Claim:
A CVD apparatus for supplying a reactive gas into a reaction chamber and forming a deposited film on a surface of a base material provided in the reaction chamber, comprising: a dry pump; a toxicity removing device; an exhaust gas recycling path for recycling an exhaust gas reaching the reaction chamber, is provided on an exhaust path for exhausting a gas from an inner part of the reaction chamber through the dry pump and the toxicity removing device, the exhaust gas recycling path is branched from a downstream side of the dry pump to recycle exhaust gas from the downstream side of the dry pump and an upstream side of the toxicity removing device, to the reaction chamber; a polymer film device for absorbing and removing an inactive gas in an exhaust gas is provided on the exhaust gas recycling path, the polymer film device removes at least one of N 2 and O 2 ; a separator for selectively removing an unnecessary exhaust gas component is provided on the exhaust gas recycling path; a compressor for raising a pressure of an exhaust gas and recycling the exhaust gas to the reaction chamber is provided on the exhaust gas recycling path; a control device for detecting a component of the exhaust gas recycled into the reaction chamber and for causing the gas component to be constant is provided on the exhaust gas recycling path; a switching device for switching the exhaust gas recycling path and a reactive gas supply path; and the exhaust gas recycling path is provided with a pressure releasing device for releasing a pressure when the exhaust gas recycling path has a constant pressure or more, and the exhaust gas recycling path is opened when a cleaning gas is to be introduced into the reaction chamber through the reactive gas supply path to clean an inner part of the reaction chamber, and a switching control is carried out by the switching device to close the exhaust gas recycling path when a deposited film is to be formed on a surface of a base material in the reaction chamber, wherein the switching device is located upstream in the gas recycling path from the polymer film device, separator, compressor, control device and pressure releasing device, and wherein the reactive gas supply path and the exhaust gas recycling path are opened in an initial stage of the cleaning during the cleaning, and a switching control is carried out by the switching device in order to close the reactive gas supply path to carry out the cleaning after the cleaning progresses.