Ozone system for multi-chamber tools

• US 20070020160A1
• Filed: 07/07/2006
• Published: 01/25/2007
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Ryan, Thomas, Berkman, Vitaly
• Granted Patent: US 7,892,502 B2
• Time in Patent Office: Days
• US Class Current: 422/186.140
• CPC Class Codes: C01B 13/11 by electric discharge
• CPC Class Codes: C01B 2201/40 using several dischargers in series
• CPC Class Codes: C01B 2201/64 Oxygen
• CPC Class Codes: C01B 2201/90 Control of the process
• CPC Class Codes: G05D 11/138 by sensing the concentration of the mixture, e.g. measuring pH value
• CPC Class Codes: Y10T 137/0318 Processes

Abstract

An improved system and method for controlling ozone concentration in connection with a multi-chamber tool. The system and method involve a first and a second concentration controller in combination with an ozone generator. The first concentration controller detects an EVENT (i.e., one of the chambers in the multi-chamber tool coming on-line or off-line) and in response provides a power instruction to the ozone generator in accordance with a predictive control algorithm. The first concentration controller has a fast (i.e, about 1 second) response time. The second concentration controller is masked from the ozone generator during the EVENT, but otherwise controls the generator after an interval of time has lapsed after the EVENT. The second concentration controller has a slower response time than the first concentration controller, however the second concentration controller provides the system with long-term stability and can be used to provide updated data to the predictive control algorithm.

Claims

1. A system for controlling the flow and concentration of ozone, the system comprising:

an ozone generator including an adjustable gas input connectable to a gas source, an adjustable power input, and a gas output connectable to a plurality of processing chambers, each of the plurality of processing chambers is set to allow a predetermined flow rate therethrough when activated;

a flow sensor used to measure a total flow rate through the plurality of processing chambers;

a first controller in communication with the flow sensor and the ozone generator, the first controller for determining an occurrence of an EVENT by comparing the total flow rate to the predetermined flow rate and for adjusting the adjustable power input of the ozone generator in accordance with data stored in a look-up table upon the occurrence of the EVENT;

a concentration sensor used to measure a concentration level of ozone in the gas output of the ozone generator; and

a second controller in communication with the concentration sensor and the ozone generator, the second controller for adjusting the adjustable power input at a given time after the occurrence of the EVENT.

2. The system of claim 1, wherein the second controller is a PID controller.

3. The system of claim 2, wherein the given time after the occurrence of the EVENT is equal to or greater than a settling time of the PID controller.

4. The system of claim 1, wherein the second controller updates data stored in the look-up table.

5. The system of claim 1 further comprising a closed-loop pressure controller connected to the ozone generator.

6. The system of claim 1, wherein the adjustable gas input comprises at least one mass flow controller.

7. The system of claim 1, wherein the adjustable gas input comprises at least one mass flow meter.

8. The system of claim 1, wherein the adjustable gas input comprises a ratio control device for controlling a concentration ratio between an oxygen source gas and a dopant carrier gas.

9. The system of claim 1, wherein the first controller has a read range than is greater than 50 percent of the predetermined flow rate.

10. A method of controlling a flow of a gas comprising:

introducing a flow of the gas to a first chamber at a concentration;

introducing the flow of the gas to a second chamber; and

using a predetermined value to adjust production of the gas such that the concentration of the gas in the first chamber remains substantially unchanged and the second chamber receives a concentration of the gas substantially the same as the concentration delivered to the first chamber after an interval of time, the interval of time being less than about 15 seconds.

11. The method of claim 10, wherein the interval of time is less than about 10 seconds.

12. The method of claim 10, wherein the gas is ozone produced in an ozone generator.

13. The method of claim 12 further comprising using the predetermined value to change power delivered to the ozone generator used to produce the flow of ozone.

14. The method of claim 10 further comprising determining the predetermined value using a predictive control algorithm.

15. A method of controlling a flow of ozone, comprising:

introducing a flow of ozone to a first chamber at a concentration;

introducing the flow of ozone to a second chamber;

adjusting a power level delivered to an ozone generator to change a rate of production of ozone to maintain a concentration of ozone in the second chamber at a value substantially the same as the concentration of ozone in the first chamber after an interval of time;

storing in memory the power level delivered; and

using the power level as a reference during a subsequent adjustment.

16. A method of controlling a flow of ozone in a system including a plurality of processing chambers, comprising:

using a predictive control algorithm to control production of ozone in an ozone generator during an occurrence of an EVENT;

using a PID controller to control production of ozone in an ozone generator after the occurrence of the EVENT and to update data used in the predictive control algorithm.

17. The method of claim 16, wherein the predictive control algorithm comprises

determining an activation event of one of the plurality of chambers from a measurement of total flow of ozone;

selecting a power output setting that corresponds to the activation event; and

adjusting power in an ozone generator to the selected power output setting.

18. A system for controlling the flow and concentration of ozone produced in an ozone generator, the system comprising:

an adjustable gas input connectable to a gas source;

an adjustable power input for regulating a concentration of ozone produced for use in a plurality of processing chambers, each of the plurality of processing chambers allowing a predetermined flow rate therethrough when activated;

a flow sensor used to measure a total flow rate through the plurality of processing chambers;

a first controller in communication with the flow sensor and the adjustable power input, the first controller determining an occurrence of an EVENT by comparing the total flow rate to the predetermined flow rate and adjusting the adjustable power input in accordance with data stored in a look-up table upon the occurrence of the EVENT;

a concentration sensor used to measure a concentration level of ozone produced; and

a second controller in communication with the concentration sensor and the adjustable power input, the second controller adjusting the adjustable power input at a given time after the occurrence of the EVENT.

19. The system of claim 18, wherein the given time after the occurrence of the EVENT is equal to or greater than a settling time of the second controller.

20. The system of claim 18, wherein the given time after the occurrence of the EVENT is about 5 to 15 seconds.