| 摘要 |
PURPOSE: A mass flow controller by adjusting digital gain and an operation method are provided to expand the use scope of the mass flow controller, and to reduce the number of the mass flow controllers in manufacturing semiconductors by processing the multiple flow range and gas with the single mass flow controller. CONSTITUTION: The digital gain is measured according to the flow range or the kind of gas of the mass flow controller during manufacturing process, and the lookup table of the measure digital gain is stored in the control circuit unit(S100). A user selects the desired flow range and the kind of gas within the maximum flow range of the mass flow controller through the user interface program in a computer(S200). The digital gain is selected corresponding to data on the flow range and the kind of gas from the computer by the control circuit unit, and the digital resistance value is adjusted automatically corresponding the selected digital gain(S300). After the user adjusts the digital gain according to the flow range and the kind of gas, the control circuit unit calculates the mass flow based on temperature change from gas flow by the sensor. The gas flow is increased or decreased by regulating the valve with comparing the calculated flow with the set flow(S400).
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