Film formation apparatus and method of using the same

A method for using a film formation apparatus for a semiconductor process, the apparatus comprising

• a reaction chamber configured to accommodate a target substrate,
• a heater configured to heat an interior of the reaction chamber,
• an exhaust system configured to exhaust the interior of the reaction chamber,
• a film formation gas supply circuit configured to supply a film formation gas into the reaction chamber to perform film formation of forming a film on the target substrate,
• a cleaning gas supply circuit configured to supply a cleaning gas into the reaction chamber to perform cleaning inside the reaction chamber,
• a concentration measuring section including an infrared sensor disposed on the exhaust system to monitor concentration of a predetermined component contained in exhaust gas from the reaction chamber,
• an information processor configured to compare a measurement value obtained by the concentration measuring section with a preset value and to thereby determine an end point of the cleaning, and
• a control section configured to control an operation of the apparatus, and
• the method being performed under control of the control section and comprising:
• performing film formation of forming a film on a target substrate by use of TEOS (Si(C2H5O)4) inside the reaction chamber, wherein a by-product film is deposited inside the reaction chamber during the film formation;
• performing cleaning inside the reaction chamber to remove the by-product film deposited inside the reaction chamber, while supplying the cleaning gas into the reaction chamber, and setting the interior of the reaction chamber at a temperature and a pressure to cause the cleaning gas to react with the by-product film;
• monitoring concentration of ethanol generated due to etching of the by-product film by the cleaning gas and contained in exhaust gas from the reaction chamber, by the infrared sensor in a predetermined period of the cleaning, the infrared sensor being configured to measure the concentration of the ethanol based on a wavelength absorbed by the ethanol when infrared rays are radiated onto the exhaust gas;
• comparing a measurement value of the concentration of the ethanol with a preset value by the information processor, and thereby determining an end point of the cleaning;
• and finishing the cleaning based on the end point.