High-speed film forming method by microwave plasma chemical vapor deposition (CVD) under high pressure and an apparatus therefor

A high speed film forming apparatus by microwave plasma chemical vapor deposition (CVD) under high pressure relative to pressures at which microwave plasma CVD apparatus normally operate, comprising;

• a reaction unit having a storage circuit for allowing progressive waves of microwave to circulate or reflect so as to accumulate said microwave, provided at part of said storage circuit with an incident-emission window through which said microwave is passable, provided with an airtight reaction chamber capable of holding therein a substrate to form thereon a desired thin film, and forming at said reaction chamber a supply pipe and an exhaust pipe for carrier gas and reaction gas communicating therewith respectively;
• a microwave generator for supplying to said reaction unit progressive waves of microwave of a predetermined wavelength;
• a waveguide unit for guiding to said reaction unit said microwave generated by said microwave generator and having at least a waveguide pipe;
• a gas supply unit for adjusting flow rates of said carrier gas and reactant gas and supplying said gases to said supply pipe of said reaction unit;
• an exhaust unit for adjusting flow rates of said carrier gas and reactant gas and exhausting said gases from said exhaust pipe at said reaction unit through a buffer tank by a vacuum pump, and
• a gas processing unit for supplying purging gas to said buffer tank and said supply pipe for said reaction gas and provided with a bubbling tank which is connected to said buffer tank so as to process a mixed gas comprising said reaction gas, carrier gas and purging gas.