MEASURING METHOD AND CONTROLLER FOR FLOW RATE OF GASEOUS HCL IN CVD DEVICE

摘要

PURPOSE:To always exactly measure and control the flow rate of gaseous HCl from a measured temp. by forming a calibration curve from the flow rate of the gaseous HCl and the temp. in a part of a reaction furnace. CONSTITUTION:The calibration curve of the temp.-flow rate of the gaseous HCl is formed by changing the flow rate of the gaseous HCl in a 0 to 50% range and measuring the temp. in the flange part 15 of the reaction furnace 2 by a temp. sensor 16 with the CVD device. The flow rate of the gaseous HCl is determined in real time from the calibration curve if the temp. of the flange part 15 is measured by the sensor 16 during reaction. The detected temp. T is converted to a digital value by an A/D converter 17 and is inputted to a controller 18. The controller 18 outputs the control signal corresponding to the difference between the detected temp. T and the set temp. to a mass flow controller 12 which regulates the flow rate of the gaseous HCl.