METHODS AND ASSEMBLIES FOR GAS FLOW RATIO CONTROL

• US 20170271184A1
• Filed: 03/15/2016
• Published: 09/21/2017
• Est. Priority Date: 03/15/2016
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Brashear, Kevin, Okada, Ashley M., Demars, Dennis L., Ye, Zhiyuan, Rajaram, Jaidev, Josephson, Marcel E.
• Granted Patent: US 10,453,721 B2
• Time in Patent Office: Days
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: H01L 21/67017 Apparatus for fluid treatment H01L21/67126, H01L21/6715 take precedence
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

Methods and gas flow control assemblies configured to deliver gas to process chamber zones in desired flow ratios. In some embodiments, assemblies include one or more MFCs and a back pressure controller (BPC). Assemblies includes a controller, a process gas supply, a distribution manifold, a pressure sensor coupled to the distribution manifold and configured to sense back pressure of the distribution manifold, a process chamber, a one or more mass flow controllers connected between the distribution manifold and process chamber to control gas flow there between, and a back pressure controller provided in fluid parallel relationship to the one or more mass flow controllers, wherein precise flow ratio control is achieved. Alternate embodiments include an upstream pressure controller configured to control flow of carrier gas to control back pressure. Further methods and assemblies for controlling zonal gas flow ratios are described, as are other aspects.

Claims

1. A method of controlling flow of a gas to a process chamber, comprising:

providing a distribution manifold fluidly coupled to a process chamber;

providing a process gas supply fluidly coupled to the distribution manifold, the process gas supply including an upstream pressure controller operationally coupled to a carrier gas, and one or more process gases whose flow is controlled by one or more supply mass flow controllers;

providing one or more mass flow controllers fluidly coupled between the process chamber and the distribution manifold;

controlling gas flow through each of the one or more mass flow controllers to a dynamically-controllable flow set point; and

controlling back pressure of the distribution manifold to a back pressure set point by controlling carrier gas flow with the upstream pressure controller.

2. The method of claim 1, further comprising:

flowing the gas flow through the one or more mass flow controllers and into one or more zones of the process chamber.

3. The method of claim 1, wherein the process chamber is a semiconductor process chamber.

4. The method of claim 1, wherein the dynamically-controllable flow set point for each of the one or more mass flow controllers is set to a nominal flow rate +/−

1%.

5. The method of claim 1, further comprising a plurality of mass flow controllers and one, and only one, upstream pressure controller.

6. The method of claim 1, wherein the upstream pressure controller controls the carrier gas flow to a junction where the carrier gas flow and process gas flows are mixed.

7. The method of claim 1, wherein the upstream pressure controller is fluidly coupled upstream of the distribution manifold.

8. The method of claim 1, wherein the upstream pressure controller controls flow of carrier gas in parallel with a carrier gas mass flow controller.

9. The method of claim 1, wherein the back pressure set point is set by a controller operatively connected to the upstream pressure controller.

10. The method of claim 1, wherein one of the one or more mass flow controllers supplies gas to a first zone of the process chamber, and another one of the one or more mass flow controllers supplies gas to a second zone of the process chamber.

11. The method of claim 1, wherein the upstream pressure controller controls a supply of the carrier gas to be mixed with the one or more process gases.

12. The method of claim 1, wherein 100% of carrier gas and the one or more process gases is delivered to the process chamber.

13. The method of claim 1, wherein only a part of the carrier gas flows through the upstream pressure controller.

14. The method of claim 1, wherein a carrier gas mass flow controller can be set to a desired carrier gas flow set point and the upstream pressure controller may be modulated to control the back pressure of the distribution manifold.

15. A gas flow control assembly, comprising:

a controller;

a process gas supply including a carrier gas and one or more process gases;

a distribution manifold fluidly coupled to the process gas supply;

a back pressure sensor fluidly connected to the distribution manifold and configured to sense back pressure in the distribution manifold;

a process chamber including a plurality of zones;

a plurality of mass flow controllers, each of the mass flow controllers fluidly and operatively connected between the distribution manifold and the process chamber and configured to control gas flow into the plurality of zones of the process chamber; and

an upstream pressure controller fluidly and operatively connected to the distribution manifold and configured to control flow of the carrier gas responsive to a back pressure set point supplied by the controller.

16. The gas flow control assembly of claim 15 wherein the controller is operatively connected to the one or more mass flow controllers to set a flow set point through each of the one or more mass flow controllers.

17. The gas flow control assembly of claim 15 wherein each of the one or more mass flow controllers is configured to flow a gas from the process gas supply at a flow rate of greater than 90 slm.

18. The gas flow control assembly of claim 15, wherein the upstream pressure controller is configured to control a flow of the carrier gas to be mixed with the one or more process gases responsive to the back pressure set point signal from the controller.

19. The gas flow control assembly of claim 15, comprising a carrier gas mass flow controller provided in a fluid parallel relationship with the upstream pressure controller.

20. A gas flow control assembly, comprising:

a controller;

a process gas supply including a carrier gas and one or more process gases configured to be mixed at a junction;

a distribution manifold fluidly coupled to the process gas supply downstream of the junction, the distribution manifold having a plurality of outlets;

a back pressure sensor operatively connected to the controller and configured to sense back pressure in the distribution manifold;

a process chamber including a plurality of zones;

one or more mass flow controllers, each of the one or more mass flow controllers fluidly and operatively connected to an outlet of the distribution manifold and to one of the plurality of zones to control a gas flow ratio into each of the plurality of zone; and

an upstream pressure controller fluidly connected to the carrier gas upstream of the junction, and operatively connected to the controller to control the back pressure to a back pressure set point responsive to an output signal from the back pressure sensor.