Gas distribution apparatus for semiconductor processing

• US 20020042205A1
• Filed: 10/25/2001
• Published: 04/11/2002
• Est. Priority Date: 10/06/2000
• Status: Active Grant

• Current Assignee: Brian K. Mcmillin, Robert Knop
• Original Assignee: Brian K. Mcmillin, Robert Knop
• Inventors: Knop, Robert, McMillin, Brian K.
• Granted Patent: US 6,508,913 B2
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• 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 21/67069 for drying etching
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: Y10S 438/935 Gas flow control

Abstract

A gas distribution system for processing a semiconductor substrate includes a plurality of gas supplies, a mixing manifold wherein gas from the plurality of gas supplies is mixed together, a plurality of gas supply lines delivering the mixed gas to different zones in the chamber, and a control valve. The gas supply lines include a first gas supply line delivering the mixed gas to a first zone in the chamber and a second gas supply line delivering the mixed gas to a second zone in the chamber. The control valve controls a rate of flow of the mixed gas in the first and/or second gas supply line such that a desired ratio of flow rates of the mixed gas is achieved in the first and second gas supply lines. In a method of using the apparatus, a semiconductor substrate is supplied to the reaction chamber and the substrate is processed by supplying the mixed gas to the first and second zones, the control valve being adjusted such that a rate of flow of the mixed gas in the first and/or second gas supply line provides a desired ratio of flow rates of the mixed gas in the first and second zones.

Claims

1. A gas distribution system useful for a reaction chamber used in semiconductor substrate processing, comprising:

a plurality of gas supplies;

a mixing manifold wherein gas from the plurality of gas supplies is mixed together;

a plurality of gas supply lines delivering the mixed gas to different zones in the chamber, the gas supply lines including a first gas supply line delivering the mixed gas to a first zone in the chamber and a second gas supply line delivering the mixed gas to a second zone in the chamber;

at least one control valve controlling a rate of flow of the mixed gas in the first and/or second gas supply line such that a desired ratio of flow rates of the mixed gas is achieved in the first and second gas supply lines;

at least one flow measurement device measuring flow rate of the mixed gas in the first and/or second gas supply line; and

a controller operating the at least one control valve in response to the flow rate measured by the at least one flow measurement device.

2. The gas distribution system of claim 1, wherein the controller comprises a computer or programmable logic device which operates the at least one control valve such that a proportion of the mixed gas delivered to at least one of the plurality of gas supply lines is changed from a first setpoint to a second setpoint during processing of a semiconductor substrate in the chamber.

3. The gas distribution system of claim 1, wherein the control valve and flow measurement device are located along the first gas supply line.

4. The gas distribution system of claim 1, wherein the at least one control valve comprises first and second control valves and the at least one flow measurement device comprises first and second flow measurement devices, the first control valve and the first measurement device are located along the first gas supply line and the second control valve and the second flow measurement device are located along the second gas supply line.

5. The gas distribution system of claim 1, wherein the at least one control valve and the at least one flow measurement device comprise a single control valve and a single flow measurement device located along the first gas supply line, the apparatus further including a flow restricting device located along the second gas supply line.

6. The gas distribution system of claim 1, wherein the control valve comprises a variable splitter valve operable to deliver a first proportion of the mixed gas to the first supply line and deliver a second proportion of the mixed gas to the second gas supply line.

7. The gas distribution system of claim 6, wherein the at least one flow measurement device comprises first and second flow measurement devices, the first flow measurement device measuring flow rate of the mixed gas in the first gas supply line, the second flow measurement device measuring flow rate of the mixed gas in the second gas supply line, and the controller operating the at least one control valve in response to the flow rates measured by the first and second flow measurement devices.

8. The gas distribution system of claim 1, wherein the at least one control valve comprises a first control valve located along the first gas supply line and a second control valve located along the second gas supply line, the controller operating the first control valve so as to be in a full open position and actively operating the second control valve to provide a lower flow rate in the second gas supply line than in the first gas supply line.

9. The gas distribution system of claim 1, wherein the at least one control valve comprises a first control valve located along the first gas supply line and a second control valve located along the second gas supply line, the controller operating the first control valve so as to be in a full open position and actively operating the second control valve to force more flow through the first gas supply line.

10. The gas distribution system of claim 1, further comprising mass flow controllers between the gas supplies and the mixing manifold, the mass flow controllers controlling flow rates of the gas supplies into the mixing manifold.

11. The gas distribution system of claim 1, wherein the chamber comprises a plasma etching chamber wherein RF energy is used to energize the mixed gas into a plasma state.

13. The method of claim 12, wherein the controller operates the at least one control valve such that the rate of flow of the mixed gas in the first gas supply line is changed from a first setpoint to a second setpoint during the processing of the substrate.

14. The method of claim 12, wherein the flow rate of the mixed gas in the first gas supply line is measured and the at least one control valve is adjusted to control the flow rate of mixed gas in the first gas supply line.

15. The method of claim 12, wherein the at least one control valve comprises a first control valve in the first gas supply line and a second control valve in the second gas supply line, the method including measuring the flow rates of the mixed gas in the first and second gas supply lines and adjusting the first and/or second control valve to control the flow rates of mixed gas in the first and second gas supply lines.

16. The method of claim 12, further comprising measuring the flow rate of the mixed gas in the first gas supply line, adjusting the at least one control valve to control the flow rate of the mixed gas in the first gas supply line, and directing the mixed gas through a flow restricting device in the second gas supply line.

17. The method of claim 12, wherein the at least one control valve comprises a variable splitter valve, the method including operating the variable splitter valve to deliver a first proportion of the mixed gas to the first supply line and deliver a second proportion of the mixed gas to the second gas supply line.

18. The method of claim 17, wherein the at least one flow measurement device measures the flow rate of the mixed gas in the first and second gas supply lines and the control valve is operated in response to the measured flow rates.

19. The method of claim 12, wherein the semiconductor substrate comprises a silicon wafer and the method includes dry etching a dielectric, semiconductive or conductive layer of material on the wafer.

20. The method of claim 12, wherein the method includes depositing a layer of material on the semiconductor substrate.

21. The method of claim 12, further comprising operating mass flow controllers between the gas supplies and the mixing manifold to control flow rates of the gas supplies into the mixing manifold.

22. The method of claim 12, wherein the chamber comprises a plasma etching chamber wherein RF energy is inductively coupled into the chamber, the method including etching the substrate with the plasma.

23. The method of claim 12, wherein the chamber comprises a plasma etching chamber wherein plasma is generated in the chamber, the method including etching silicon dioxide, aluminum or polysilicon on the substrate with the plasma.

24. The method of claim 12, wherein the chamber comprises a plasma etching chamber wherein plasma is generated in the chamber, the method including mixing at least one halogen gas selected from Cl₂, HCl₃ and HBr with O₂, N₂ or a fluorocarbon selected from CHF₃ and CF₄ in the mixing manifold, energizing the mixed gas into a plasma state, and etching the substrate with the plasma.

25. The method of claim 12, wherein the chamber comprises a plasma etching chamber wherein plasma is generated in the chamber, the method including mixing a fluorocarbon with O₂ or C₂H₄, energizing the mixed gas into a plasma state, and etching the substrate with the plasma.

26. The method of claim 12, wherein the controller monitors total gas flow supplied by the gas supplies to the mixing manifold and compares the total gas flow and the measured gas flow in one of the gas supply lines to a target flow for the second gas supply line, the at least one control valve being repeatedly adjusted by the controller to achieve the desired ratio of flow rates in the first and second gas supply lines.

27. The method of claim 26, wherein first and second mass flow controllers are used, the first mass flow controller being operated in full open position and the second mass flow controller set point being repeatedly adjusted.

28. The method of claim 26, wherein first and second mass flow controllers are used and the split gas flow settling time is decreased by repeatedly applying a new set point to the controlled mass flow controller based on the current flow reading plus a multiple of the difference between the current and target flow.

12. A method of processing a substrate in a reaction chamber wherein a gas distribution system includes a plurality of gas supplies, a mixing manifold wherein gas from the plurality of gas supplies is mixed together, a plurality of gas supply lines delivering the mixed gas to different zones in the chamber, the gas supply lines including a first gas supply line delivering the mixed gas to a first zone in the chamber and a second gas supply line delivering the mixed gas to a second zone in the chamber, at least one control valve controlling a rate of flow of the mixed gas in the first and/or second gas supply line such that a desired ratio of flow rates of the mixed gas is achieved in the first and second gas supply lines, at least one flow measurement device measuring flow rate of mixed gas in the first and/or second gas supply line, and a controller operating the at least one control valve in response to the flow rate measured by the at least one flow measurement device, the process comprising:

supplying a semiconductor substrate to the reaction chamber;

measuring flow rate of mixed gas in the first and/or second gas supply line with at least one flow measurement device; and

processing the substrate by supplying the mixed gas to the first and second zones, the at least one control valve being adjusted by the controller in response to the flow rate measured by the at least one flow measurement device.