Flowrate control methods based on PLC in wafer clean tool

Flowrate control methods based on PLC in wafer clean tool

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Several in common use flowrate control methods in semiconductor wafer clean tool are introduced in this paper, including the flowrate control of process chamber and chemical proportioning, then corresponding control methods are brought forward according tiamats rebuke to different applications.The chemical flowrate is directly used as the feedback signal of closed control in single chamber clean tool, and the fluctuation of chemical flowrate is reduced when the pneumatic valve is switched by controlling the balance between dispense and return tube opening.The pressure closed loop control method is adopted to control the flowrate indirectly in multi-chamber clean tool, the series control design of magnetic suspension pump can effectively improve the service life and pressure stability of the pump, and by adjusting qf1510 the needle valve in each chamber, the difference of the flowrate of each chamber is reduced.

Generally, by controlling the injection flowrate of each chemical, a variety of chemical mix functions can be realized.Flowrate precision directly affects the accuracy of the composition of process chemical.Clean tool integration control based on PLC has the features of flexble in use, good stability, and high dependability, and is applicable for real-time and precise control of different module.