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Apparatus and method for injecting and modifying gas concentration of a meta-stable or atomic species in a downstream plasma reactor

Imported: 24 Feb '17 | Published: 09 Sep '03

Ronald Allan Powell, Gabriel I. Font-Rodriguez, Simon Selitser, Emerson Derryck Settles

USPTO - Utility Patents

Abstract

An apparatus and method for injecting gas within a plasma reactor and tailoring the distribution of an active species generated by the remote plasma source over the substrate or wafer. The distribution may be uniform, wafer-edge concentrated, or wafer-center concentrated. A contoured plate or profiler modifies the distribution. The profiler is an axially symmetric plate, having a narrow top end and a wider bottom end, shaped to redistribute the gas flow incident upon it. The method for tailoring the distribution of the active species over the substrate includes predetermining the profiler diameter and adjusting the profiler height over the substrate. A coaxial injector tube, for the concurrent injection of activated and non-activated gas species, allows gases to be delivered in an axially symmetric manner whereby one gas can be excited in a high density RF plasma, while the other gas can be prevented from excitation and/or dissociation caused by exposure to the plasma or heated surfaces in the source apparatus. The profiler is used in conjunction with the coaxial injector tube for redistributing the excited gases emerging from the injector tube, while allowing the non-excited gases to pass through its center.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic representation of a prior art remote PECVD reactor.

FIG. 2 is an elevated cross-sectional view of a remote PECVD reactor with a contoured plate implemented for gas distribution.

FIG. 3 is a computer generated distribution calculation using a contoured plate in a remote plasma reactor chamber.

FIG. 4 depicts a normalized N

2* concentration across the wafer as a function of wafer to profiler distance.

FIG. 5 depicts an elevated cross-sectional view of a coaxial remote plasma source and chamber.

FIG. 6A is an elevated cross-sectional view of the multiple layers of the coaxial injector tube.

FIG. 6B is a top view of a remote PECVD reactor having a profiler and coaxial injector tube.

Claims

1. A method for injecting gas into a remote plasma enhanced chemical vapor deposition reactor such that a first gas is excited by plasma energy while a second gas remains unexcited by said plasma energy, said method comprising:

2. The method of claim 1 wherein said step (f) comprises flowing said first and second gases simultaneously into said chamber through said input port.

3. The method of claim 1 wherein said step (a) further comprises providing said remote plasma source adapted to house a coaxial injector tube.

4. The method of claim 1 wherein injecting said first gas includes injecting any one of the following gases: He/N

2, He/O

2, O

2, N

2, Ar/N

2, Ar/O

2, He, Ar, He/H

2, or H

2.

5. The method of claim 1 wherein injecting said second gas comprises injecting He/SiH

4.

6. The method of claim 1 wherein said first gas and said second gas are the same type of gas.

7. The method of claim 1 wherein said step (e) further includes providing a Faraday shield confining said second gas and traversing through said plasma region.

8. The method of claim 7 wherein said step (e) further includes coating said Faraday shield with an infrared reflective coating.

9. The method of claim 1 comprising injecting said first gas against a profiler such that said first gas is dispersed by said profiler while said second gas is directed within said chamber uninhibited by said profiler.

10. A method of injecting gas into a remote plasma enhanced chemical vapor deposition reactor such that a first gas is excited by plasma energy while a second gas remains unexcited by said plasma energy, and normalizing the distribution of the gases on a wafer surface, said method comprising:

11. The method of claim 10 further comprising the steps of:

12. The method of claim 10 wherein said step (g) comprises flowing said first and second gases simultaneously into said chamber through said input port.

13. The method of claim 10 wherein said step (a) further comprises providing said remote plasma source adapted to house a coaxial injector tube.

14. The method of claim 10 wherein said first gas and said second gas are the same type of gas.

15. A method for injecting gas into a remote plasma enhanced chemical vapor deposition reactor such that a first gas is excited by plasma energy while a second gas remains unexcited by said plasma energy, said method comprising:

16. A method for injecting gas into a remote plasma enhanced chemical vapor deposition reactor such that a first gas is excited by plasma energy while a second gas remains unexcited by said plasma energy, and normalizing the distribution of the gases on a wafer surface, said method comprising:

17. A method for injecting gas into a remote plasma enhanced chemical vapor deposition reactor such that a first gas is excited by plasma energy while a second gas remains unexcited by said plasma energy, and normalizing the distribution of the gases on a wafer surface, said method comprising: