Patent ID: 8043438

Claim:
A method for cleaning a CVD apparatus comprising: a reactive gas introducing device for applying a high frequency to a reactive gas supplied into a reaction chamber through a reactive gas supply path and changing the reactive gas into a plasma, and supplying the reactive gas thus changed into the plasma into the reaction chamber; and a counter electrode stage provided in the reaction chamber and serving to mount a base material for forming a deposited film, the deposited film being formed on a surface of the base material over the counter electrode stage with the reactive gas changed into the plasma introduced into the reaction chamber through the reactive gas introducing device, the method comprising: introducing a cleaning gas into the reaction chamber; forming a high frequency plasma by generating a high frequency electric field from the high frequency applying device provided in the reaction chamber; detoxifying a by-product gasified by the cleaning gas and deposited in the reaction chamber and discharging the detoxified by-product to the outside of the reaction chamber by a harm removing device; carrying out an optical emission spectral analysis of an F radical in the reaction chamber using at least an optical emission spectroscopy (OES) provided in the reaction chamber to measure a luminous intensity; monitoring FLi + or F 2 Li + as an F intensity in the reaction chamber using an ion attachment type mass spectroscopy (IAMS); monitoring the concentration of SiF 4 in the gas discharged from the reaction chamber by a Fourier transform infrared spectrometry (FTIR) provided on a gas discharging path for discharging the gas from the reaction chamber; comparing monitored luminous intensity data, monitored F intensity data, and monitored concentration data of SiF 4 , with pre-stored luminous intensity data, pre-stored F intensity data, and pre-stored concentration data of SiF 4 , respectively; stopping introducing the cleaning gas to end the cleaning at the earliest of a passage of a predetermined time from the time when the monitored luminous intensity reaches a luminous intensity saturation point, a passage of a predetermined time from the time when the monitored F intensity reaches an F intensity saturation point, and a time when the monitored concentration data of SiF 4 reaches a predetermined cleaning endpoint concentration, wherein the predetermined time is an arbitrary time between 15 seconds and 50 seconds, and the predetermined cleaning endpoint concentration is 100 ppm.