INTERNAL PRESSURE REGULATOR FOR ORDINARY-PRESSURE CVD REACTION FURNACE

摘要

PURPOSE:To fix the internal pressure of the ordinary-pressure CVD reaction furnace by automatic control by detecting the gas pressure in an exhaust pipe with a pressure sensor and controlling a flow regulator by the detection signal through a control circuit. CONSTITUTION:SiH4, O2 and N2 are mixed in an appropriate ratio by a gaseous reactant feeder 3 and supplied into the reaction furnace 1 under specified pressure. SiO2 is formed from the supplied gaseous reactant G, and the remaining gas G' is discharged into a common exhaust passage 5 from an exhaust port 18 through an exhaust pipe 4. The exhaust pipe 4 is branched, a pressure sensor 7 for detecting the gas pressure in the furnace is provided, and a flow regulator 9 is inserted in series with the exhaust pipe 4. Meanwhile, a control circuit 8 for receiving the detection signal of the sensor 7 and transmitting the flow control signal to the regulator 9 is provided. The regulator 9 is controlled by the detection signal of the sensor 7 through the control circuit 8 to control the flow rate of the exhaust gas discharged into the common exhaust passage 5, and the internal pressure of the furnace 1 is fixed.