A method and apparatus for controlling the delivery of a gas from a reservoir to a semiconductor process chamber. In accordance with the present invention, a reservoir, having an inlet and outlet isolation valve and a known volume, is filled with a gas upon the initiation of process recipe step. The temperature and pressure of the gas in the reservoir are measured to determine an initial mass of the gas residing within the reservoir. The flow of gas from the reservoir to the process chamber is metered by a variable flow valve under the control of a self-calibrating, dynamic flow control circuit comprising a flow control servo loop (flow control circuit) and a calibration servo loop (calibration circuit). The variable flow valve is situated in a gas flow path between the reservoir and process chamber at a point upstream of a orifice. In operation, gas is delivered to the process chamber by releasing the gas from the reservoir and directing the gas through the variable flow valve and sonic orifice and into the process chamber. The flow control servo loop is used to dynamically control the variable flow valve in response to a measured gas flow rate. When the flow of gas to the process chamber is terminated, the temperature and pressure of the gas residing in the reservoir is again measured to determine the final mass of gas residing in the reservoir. The initial mass and final mass of gas values are compared to determine the actual mass of gas released from the reservoir during the recipe step. This value serves as an input to the calibration servo loop to update the system calibration constant. The execution of the calibration servo loop serves as a continuous self calibration of the dynamic servo loop.

Dynamic gas flow controller

A system and method for controlling a mass flow controller to have a constant control loop gain under a variety of different types of fluids and operating conditions, and for configuring the mass flow controller for operation with a fluid and/or operating conditions different from that used during a production of the mass flow controller. Further, the system and method includes providing control by reducing the effects of hysteresis in solenoid actuated devices by providing a non-operational signal to the solenoid actuated device.

System and method for a mass flow controller

A gas delivery system accurately measures and optionally regulates mass flow rate in real time. A fluid conduit connects an inlet valve, calibration volume, flow restrictor, and outlet valve in series. Pressure and temperature sensors are coupled to the calibration volume. One or more pressure sensors may be attached across the flow restrictor. Alternatively, an absolute pressure sensor may be attached upstream of the flow restrictor. One embodiment of differential pressure sensors comprises a floating reference differential pressure sensor, including a first transducer attached to the fluid conduit upstream of the flow restrictor and a second transducer attached to the conduit downstream of the flow restrictor. In this embodiment, each transducer receives a reference pressure from a reference source, and optionally, after the calibration volume is charged, the floating reference differential pressure transducers are calibrated. When gas flow is initiated, differential and/or absolute pressure measurements are repeatedly taken, and a measured mass flow rate calculated thereon. Gas flow is adjusted until the measured mass flow rate reaches a target mass flow. Using the temperature/pressure sensors at the calibration volume, repeated calculations of actual flow rate are made to uncover any discrepancy between actual and measured mass flow rates. Whenever a discrepancy is found, the manner of calculating measured mass flow is conditioned to account for the discrepancy; thus, the measured mass flow rate more accurately represents the actual mass flow rate thereby providing an actual mass flow rate more accurately achieving the target mass flow rate.

Method for wide range gas flow system with real time flow measurement and correction

An on-off device disposed at each of the inlet and the outlet of a fluid controller is one of five kinds of on-off devices, i.e., on-off device having a two-port valve, on-off device having a two-port valve and a three-port valve, on-off device having a two-port valve and two three-port valves, on-off device having two three-port valves, and on-off device having three three-port valves, The main bodies of two-port valves of all types of on-off devices are identical in configuration and each have an inlet and an outlet in a bottom face thereof. Main bodies of three-port valves of all types of on-off devices are identical in configuration and each formed in a bottom face thereof with an inlet, an outlet always in communication with the inlet, and an inlet-outlet subopening.

Fluid control apparatus

A fluid control device has formed in a valve main body a main channel communicating with an inlet of a channel within a massflow controller, and a relatively long subchannel and a relatively short subchannel both communicating with the main channel. The process gas to be assure of high purity is passed through the relatively long subchannel.

Fluid control device

In a flow quantity test system for a mass flow controller, a gas source for measurement is provided to supply gas for measurement. A cutoff valve for start of measurement is connected at its inlet port to the gas source for measurement and is connected at its outlet port to an inlet port of the mass flow controller. The cutoff valve for start of measurement is opened to flow the gas for measurement therethrough and closed to block the flow of the gas for measurement therethrough. A pressure gauge is provided to detect pressure of the gas for measurement appearing at the outlet port side of the cutoff valve for start of measurement. A microcomputer is provided to close the process gas cutoff valve and open the cutoff valve for start of measurement to change pressure detected by the pressure gauge. The microcomputer further closes the cutoff valve for start of measurement after pressure detected by the pressure gauge has reached predetermined pressure and measures lowering of pressure detected by the pressure gauge dependent on lapse of time after closing of the cutoff valve for start of measurement. Thereafter the microcomputer tests measuring precision of the mass flow controller in accordance with the measured lowering of the detected pressure.

Flow quantity test system for mass flow controller

PURPOSE:To provide a gas supply system for feeding process gas, which is likely to liquefy at normal temperature under normal pressure, precisely at a predetermined flow rate while heating it. CONSTITUTION:A gas supply system for feeding dichlorosilane F, which is likely to liquefy at normal temperature under normal pressure, comprises a solenoid valve 53 provided with a mass flow meter to measure the mass flow of dichlorosilane F and pass it at a predetermined flow rate; an input block 10 connected with the input port of the solenoid valve 53; an input switch valve 52 provided on the input block 10; an output block 11 connected with the output port of the solenoid valve 53; an output switch valve 54 provided with the output block 11; and rod heaters 14 and 15 embedded in the input and output blocks 10 and 11.

Gas supply system

PURPOSE: To provide a mass flow controller rate examination system which can examine the flow rate measuring precision of mass flow controllers in a state where they are incorporated in piping as they are. CONSTITUTION: When cutoff valves 3A-3E are closed, and cutoff valves 9, 4A-4E and 2A-2E are opened, process gas is scavenged from within piping and the piping is filled with nitrogen gas with prescribed pressure. Then, the valve 9 is closed and nitrogen gas in the piping is discharged through the mass flow controllers 1A-1E. This when the indication value of a pressure gage 10 becomes a prescribed value is measured, and the real flow rates of the mass controllers 1A-1E are obtained. Thus, the abnormality of the mass controllers 1A-1E can be detected. COPYRIGHT: (C)1994,JPO&Japio

Yoshihisa Sudo

Papers

Flow quantity test system for mass flow controller

Gas supply system

Mass flow controller flow rate verification system