FLUIDSTRÖMUNGSSTEUERUNG UND VERFAHREN ZUM BETRIEB

摘要

A fluid mass flow controller, particularly adapted for controlling mass flow rates of toxic and reactive gases used in semiconductor device fabrication, includes a control circuit connected to pressure sensors for sensing the differential pressure across a flow restrictor in the mass flow controller for controlling a valve to control the fluid mass flow rate to a setpoint. The control circuit compares the differential pressure with the downstream pressure at a measured temperature with a data set of a gas passing through the flow controller for a range of differential pressures and downstream pressures and adjusts the flow control rate accordingly. The flow controller is mechanically uncomplicated including a two part body for supporting the pressure sensors, a remotely controllable flow control valve and the flow restrictor. The flow restrictor may comprise an orifice or nozzle but preferably comprises a sintered metal plug having a predetermined porosity for the expected materials and flow conditions to which the flow controller will be exposed. Process gases to be controlled by the flow controller are tested to provide data sets of mass flow rates at selected temperatures for a range of differential pressures across a flow restrictor and a range of downstream pressures.