ADVANCED PROCESS SENSING AND CONTROL USING NEAR INFRARED SPECTRAL REFLECTOMETRY

• US 20090218314A1
• Filed: 02/29/2008
• Published: 09/03/2009
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lian, Lei, Davis, Matthew Fenton
• Granted Patent: US 8,009,938 B2
• Time in Patent Office: Days
• US Class Current: 216/60
• CPC Class Codes: G01N 21/73 using plasma burners or torches
• CPC Class Codes: G02B 6/04 formed by bundles of fibres G02B6/24 takes precedence
• CPC Class Codes: G02B 6/40 having fibre bundle mating means
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32972 Spectral analysis
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

Embodiments described herein provide a method and apparatus for obtaining process information in a substrate manufacturing process using plasma. In one embodiment, a chamber is provided having one or more optical metrology modules that are positioned such that optical energy from the plasma process is detected at substantially orthogonal angles. Metrics derived from detected optical energy may be used for endpoint determination, substrate temperature, and monitoring of critical dimensions on the substrate.

Claims

1. A processing chamber comprising:

a chamber body assembly having a processing volume;

a showerhead assembly coupled to a ceiling of the chamber body and having a region transmissive to an optical metrology signal;

an optical monitoring device arranged to view the processing volume at a radial position of the chamber body; and

a spectral sensing system arranged to view the processing volume of the chamber body through the transmissive region of the showerhead assembly at an angle orthogonal to the plane of the showerhead.

2. The processing chamber of claim 1, wherein the spectral sensing system comprises a fiber optic bundle.

3. The processing chamber of claim 2, wherein the fiber optic bundle further comprises:

a first active portion comprising a plurality of first source fibers and a plurality of first signal fibers;

a second active portion comprising a plurality of second source fibers and a plurality of second signal fibers; and

a third inactive portion comprising a plurality of inactive fibers.

4. The processing chamber of claim 3, wherein a portion of the plurality of first source fibers are arranged in a spaced-apart relationship relative to the plurality of first signal fibers.

5. The processing chamber of claim 4, wherein the portion of the first plurality of first source fibers and the plurality of first signal fibers are arranged alternately in a substantially circular geometry.

6. The processing chamber of claim 3, wherein each of the plurality of second signal fibers are adjacent at least one of the plurality of first source fibers and at least one of the plurality of first signal fibers.

7. The processing chamber of claim 6, wherein the plurality of second signal fibers are arranged in a substantially circular geometry and one of the plurality of second source fibers therebetween.

8. The processing chamber of claim 3, wherein the plurality of second signal fibers and the plurality of inactive fibers are arranged in a substantially circular geometry.

9. The processing chamber of claim 8, wherein each of the plurality of second signal fibers are separated by one inactive fiber.

10. A fiber optic cable bundle coupled to a radiation source and at least one spectrometer, comprising:

a plurality of optical fibers secured in a bundle, the bundle comprising a first portion comprising at least one source fiber having a first end coupled to the radiation source and a second end positioned to direct radiation from the source into a processing chamber;

a second portion comprising a plurality of first return fibers having a first end in communication with the at least one spectrometer and a second end positioned to receive optical signals originating the processing chamber; and

a third portion comprising a plurality of inactive fibers, wherein the second portion and the third portion are arranged on a common radius, and each source fiber is separated along the common radius by either at least one of the return fibers, at least one of the inactive fibers, or both return and inactive fibers.

11. The fiber optic cable bundle of claim 10, wherein the first, second, and third portions are arranged alternately in a substantially circular geometry.

12. The fiber optic cable bundle of claim 10, wherein the second portion comprises a plurality of first source fibers and a plurality of first signal fibers, each of the plurality of second signal fibers are adjacent at least one of the plurality of first source fibers and at least one of the plurality of first signal fibers.

13. The fiber optic cable bundle of claim 12, wherein the plurality of second signal fibers are arranged in a substantially circular geometry and one of the plurality of second source fibers therebetween.

14. The fiber optic cable bundle of claim 10, wherein the third portion comprises a plurality of second signal fibers that are adjacent the plurality of inactive fibers in a substantially circular geometry.

15. The fiber optic cable bundle of claim 14, wherein each of the plurality of second signal fibers are separated by one inactive fiber.

16. The fiber optic cable bundle of claim 10, wherein the fiber optic cable further comprises a substantially circular geometry which includes the second portion located radially inward relative to the third portion, and the at least one source fiber is located radially inward relative to the second portion.

17. A method for processing a substrate, comprising:

etching a substrate positioned on a substrate support disposed in an etch chamber, the substrate etched through a patterned masking layer in the presence of a plasma;

introducing optical energy into the plasma and directed towards the substrate;

collecting a first signal and a second signal from the plasma;

routing the first signal through a fiber optic bundle to a detector, wherein the fiber optic cable bundle comprises;

a first portion comprising at least one source fiber having a first end coupled to a radiation source and a second end positioned to direct radiation from the source into a processing chamber;

a second portion comprising a plurality of first return fibers having a first end in communication with at least one spectrometer and a second end positioned to receive optical signals originating the processing chamber; and

a third portion comprising a plurality of inactive fibers, wherein the second portion and the third portion are arranged on a common radius, and each source fiber is separated along the common radius by either at least one of the return fibers, at least one of the inactive fibers, or both return and inactive fibers; and

controlling the etch process in response to the collected signals.

18. The method of claim 17, wherein the first signal is generated by optical energy reflected from the substrate.

19. The method of claim 17, wherein the second signal is generated by optical energy from the plasma.

20. The method of claim 17, further comprising:

intermittently collecting the first signal while etching the substrate.

21. The method of claim 17, wherein the optical energy is directed towards the substrate at an angle normal to the plane of the substrate.

22. The method of claim 17, wherein the optical energy is directed towards the substrate by the first portion of fibers.

23. The method of claim 22, wherein the optical energy is directed towards the substrate at an angle normal to the plane of the substrate.

24. The method of claim 17, wherein the first signal is collected by the second portion at an orthogonal angle relative to the plane of the substrate.

25. The method of claim 24, wherein the second signal is collected from a radial position relative to the substrate.

26. A computer-readable medium containing instructions, that when executed by a processing system, control an etch process performed in the processing system, the etch process comprising:

etching a substrate positioned on a substrate support disposed in a processing system, the substrate etched through a patterned masking layer in the presence of a plasma;

directing optical energy through the plasma towards the substrate;

collecting a first signal and a second signal from the plasma;

routing the first signal through a fiber optic bundle to a detector, wherein the fiber optic cable bundle comprises;

a first portion comprising at least one source fiber having a first end coupled to a radiation source and a second end positioned to direct radiation from the source into a processing chamber;

a second portion comprising a plurality of first return fibers having a first end in communication with at least one spectrometer and a second end positioned to receive optical signals originating the processing chamber; and

a third portion comprising a plurality of inactive fibers, wherein the second portion and the third portion are arranged on a common radius, and each source fiber is separated along the common radius by either at least one of the return fibers, at least one of the inactive fibers, or both return and inactive fibers; and

controlling the etch process in response to the collected signals.