Abstract: A fluid mass flow control apparatus, particularly useful for controlling low flow rates of fluids used in semiconductor manufacturing processes, comprises a first elongated flow tube connected to an inlet fitting and to a capsule like valve housing and a second elongated tube connected to the inlet fitting and the valve housing and including a flow sensor. The valve housing is connected to a magnetostrictive actuator including an elongated actuator member disposed in a conduit connected to the valve housing and serving as part of the fluid flow path through the apparatus. An electromagnetic coil is disposed about the conduit and the actuator and is responsive to energization to effect controlled elongation of the actuator to control the position of a valve closure member disposed in the valve housing. Adjustments to full-scale flow ranges of the apparatus may be obtained by inserting a tube or wire in the flow sensor tube to act as a flow restrictor.

Abstract: 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.

Abstract: Fluid mass flow meters, particularly for measuring a wide range of relatively low flow rates of gas used in semiconductor fabrication processes include a body adapted to be interposed in a purge gas line leading to or from a mass flow controller or in a process gas line with the mass flow controller. The flow meter body includes a flow restrictor interposed in a passage and plural mass flow sensors which sense overlapping full scale fluid mass flow ranges across the flow restrictor to increase the overall range of fluid mass flow rates sensed by the meter. The flow meter body may include series or parallel arranged flow restrictors, a second set of mass flow sensors, and valving to cause a set of mass flow sensors to sense fluid mass flow rates across one or both of the flow restrictors. Embodiments of the flow meter include a pressure transducer mass flow sensor and conduits arranged with additional flow restrictors therein to selectively vary the full scale measurement range of the mass flow sensor.

Abstract: A fluid mass flow control apparatus, particularly useful for controlling low flow rates of fluids used in semiconductor manufacturing processes, comprises a first elongated flow tube connected to an inlet fitting and to a capsulelike valve housing and a second elongated tube connected to the inlet fitting and the valve housing and including a flow sensor. The valve housing is connected to a magnetostrictive actuator including an elongated actuator member disposed in a conduit connected to the valve housing and serving as part of the fluid flow path through the apparatus. An electromagnetic coil is disposed about the conduit and the actuator and is responsive to energization to effect controlled elongation of the actuator to control the position of a valve closure member disposed in the valve housing. Adjustments to full-scale flow ranges of the apparatus may be obtained by inserting a tube or wire in the flow sensor tube to act as a flow restrictor.

Abstract: A fluid mass flow control apparatus, particularly adapted for use in controlling fluid flow to semiconductor fabrication processes, comprises a tubular body part having inlet and outlet fittings and a bore extending therethrough and supporting a valve seat in the bore. A closure member is connected to an arm which extends laterally through a tubular spigot portion of the body part. The body part has a reduced thickness wall at the spigot portion to allow elastic deflection of the wall and movement of the arm to control the position of the closure member. An elongated tube or rod actuator on which a resistance heating coil is supported is operably connected to a control system for heating the actuator to move the arm to control flow of fluid through the apparatus. A flow restrictor is mounted upstream of the valve seat and a mass flow sensor is in communication with the passage to provide a mass flow rate signal to the control system.