Fluid control system
An improved fluid delivery system and method that directly controls the concentration of constituent components in a fluid mixture delivered, for example, to a process chamber. Pressure of the fluid mixture can also be directly controlled. A concentration sensor capable of measuring concentration of all of the constituent components in a fluid mixture is used to provide signals used to vary the flow rate of constituent gases under a closed loop feedback system. The signal output of one or more pressure sensors can also be used to provide a signal used to vary the flow rate of constituent gases under a closed loop feedback system. By directly controlling these two extremely important process variables, embodiments of the present invention provide a significant advantage in measurement accuracy over the prior art, enable real-time process control, reduce system level response time, and allow for a system with a significant footprint reduction.
1. A method of controlling the concentration of one or more gases within a gas mixture, the method comprising:
providing a plurality of gases, each gas provided by a gas source;
causing the plurality of gases to flow along a flow path so that the plurality of gases are combined into a gas mixture and delivered to a process chamber, the flow path extending from the gas sources to the process chamber and fluidly coupled to a side stream, the side stream fluidly coupled to a vacuum source;
providing a concentration sensor fluidly coupled to the side stream, the concentration sensor disposed between the vacuum source and the flow path;
determining a concentration of a first gas within the gas mixture using the concentration sensor; and
adjusting an adjustable control valve within the flow path to control the flow of a second gas of the plurality of gases in accordance with the determined concentration of the first gas within the gas mixture.
2. The method of claim 1 wherein the first and second gases are the same.
3. The method of claim 1 wherein the first and second gases are different.
4. The method of claim 1 wherein the step of adjusting further comprises adjusting a plurality of adjustable control valves within the flow path to control the flow of more than one gas of the plurality of gases.
5. The method of claim 1 wherein the step of determining comprises determining concentrations of a plurality of gases within the gas mixture using the sensor.
6. The method of claim 1 wherein the step of causing comprises using calculated setpoints to deliver the gas mixture to the process chamber at a first flow rate, the first flow rate being higher than a second flow rate used during system operation.
7. The method of claim 1 wherein the step of causing comprises using calculated setpoints to deliver the gas mixture to the process chamber at a first flow rate that is more than 50% of a maximum flow rate for the adjustable control valve.
8. The method of claim 1 wherein a first valve is fluidly coupled to the side stream and disposed between the concentration sensor and the flow path.
9. The method of claim 1 wherein the side stream further comprises a bypass line.
10. The method of claim 9 wherein a second valve is fluidly coupled to the bypass line.
11. The method of claim 9 wherein the bypass line is fluidly coupled to a vacuum source.
12. A method of controlling the concentration of one or more gases within a gas mixture, the method comprising:
providing a plurality of gases, each gas provided by a gas source;
causing the plurality of gases to flow along a flow path so that the plurality of gases are combined into a gas mixture and delivered to a process chamber, the flow path extending from the gas sources to the process chamber and fluidly coupled to a side stream, the side stream located between the gas sources and the process chamber;
providing a concentration sensor fluidly coupled to the side stream, the concentration sensor disposed within the side stream;
determining a concentration of a first gas within the gas mixture using the concentration sensor; and
adjusting an adjustable control valve within the flow path to control the flow of a second gas of the plurality of gases in accordance with the determined concentration of the first gas within the gas mixture.
13. The method of claim 12 wherein the step of adjusting further comprises adjusting a plurality of adjustable control valves within the flow path to control the flow of more than one gas of the plurality of gases.
14. The method of claim 12 wherein the step of determining comprises determining concentrations of a plurality of gases within the gas mixture using the sensor.
15. The method of claim 12 wherein the step of causing comprises using calculated setpoints to deliver the gas mixture to the process chamber at a first flow rate, the first flow rate being higher than a second flow rate used during system operation.
16. The method of claim 12 wherein a first valve is fluidly coupled to the side stream and disposed between the concentration sensor and the flow path.
17. The method of claim 12 wherein the side stream further comprises a bypass line.
18. The method of claim 17 wherein a second valve is fluidly coupled to the bypass line.
19. The method of claim 17 wherein the bypass line is fluidly coupled to a vacuum source.
20. A method of controlling the concentration of one or more gases within a gas mixture, the method comprising:
providing a plurality of gases, each gas provided by a gas source;
causing the plurality of gases to flow along a flow path so that the plurality of gases are combined into a gas mixture and delivered to a process chamber, the flow path extending from the gas sources to the process chamber and fluidly coupled to a side stream;
providing a concentration sensor fluidly coupled to the side stream;
determining a concentration of a first gas within the gas mixture using the concentration sensor; and
adjusting an adjustable control valve within the flow path to control the flow of a second gas of the plurality of gases in accordance with the determined concentration of the first gas within the gas mixture.