Use of modeled parameters for real-time semiconductor process metrology applied to semiconductor processes

• US 7,695,984 B1
• Filed: 04/20/2006
• Issued: 04/13/2010
• Est. Priority Date: 04/20/2005
• Status: Active Grant

• Current Assignee: Pivotal Systems Corporation
• Original Assignee: Pivotal Systems Corporation
• Inventors: Monkowski, Joseph R, Lane, Barton
• Primary Examiner(s): Mandala; Victor A
• Assistant Examiner(s): STOWE, SCOTT C
• Application Number:
  US11/409,308
• Time in Patent Office: 1,454 Days
• Field of Search: 438/14, 438/9, 438/5, 438/10, 438/11, 438/7, 257/E21.521, 257/E21.525, 257/E21.528
• US Class Current: 438/5
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32963 End-point detection
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

Method and system for detecting endpoint for a plasma etch process are provided. In accordance with one embodiment, the method provides a semiconductor substrate having a film to be processed thereon. The film is processed in a plasma environment during a time period to provide for device structures. Information associated with the plasma process is collected. The information is characterized by a first signal intensity. Information on a change in the first signal intensity is extracted. The change in the first signal intensity has a second signal intensity. The change in signal intensity at the second signal intensity is associated to an endpoint of processing the film in the plasma environment. The second signal intensity may be about 0.25% and less of the first signal intensity.

Claims

1. A method for processing a semiconductor device using an end-point detection process, the method comprising:

providing a semiconductor wafer having a film to be processed;

processing the film in a plasma environment during a determined time period;

collecting information associated with the plasma environment during the determined time period, the information being characterized by a first signal intensity selected from an intensity of an RF signal, a light signal, a temperature signal, a pressure signal, a voltage signal, or a gas composition signal;

extracting a change in signal intensity from the first signal intensity, the change in signal intensity having a second signal intensity;

associating the change in signal intensity at the second intensity with an end point associated with the processing of the film in the plasma environment;

whereupon the second signal intensity is about 0.25% or less of the first signal intensity.

2. The method of claim 1 wherein the extracting measures signals associated with one or more physical effects affecting with the first signal intensity.

3. The method of claim 1 wherein the extracting further removes signals associated with one or more physical effects affecting the first signal intensity.

4. The method of claim 2 wherein the extracting is based upon a mathematical model derived from one or more of the physical effects.

5. The method of claim 4 wherein the one or more physical effects comprise a phenomenon selected from at least one of a thermal effect, a magnetic interference effect, outgassing, and a polymeric material.

6. The method of claim 5 wherein the magnetic interference effect is measured using a Hall probe.

7. The method of claim 5 wherein the thermal effect is modeled using an exponential function.

8. The method of claim 1 wherein the second signal intensity is about 0.1% or less of the first signal intensity.

9. The method of claim 1 wherein the collecting comprises transferring one or more RF signals derived from one or more RF sensors coupled to one or more portions of an outer portion of a chamber maintaining the plasma environment.

10. The method of claim 1 wherein the collecting comprises transferring one or more optical signals derived from one or more sensors coupled to the plasma environment.

11. The method of claim 1 wherein the first signal intensity comprises a voltage applied to the plasma environment, a current flowing into the plasma environment, an impedance of the plasma environment, or a phase between voltage applied to the plasma environment and current flowing into the plasma environment.

12. The method of claim 11 wherein the first signal intensity is selected from a total voltage applied to the plasma environment, a total current flow to the plasma environment, a total impedance to the plasma environment, and a phase between the total voltage applied to the plasma environment and the total current flowing into the plasma environment.

13. The method of claim 1 wherein the first signal intensity comprises an optical emission intensity of one or more of the emission lines from the plasma environment.

14. The method of claim 1 further comprising storing the information associated with the plasma environment in a computer-readable storage medium.

15. The method of claim 1 wherein the processing is selected from a plasma etching process, a plasma-based deposition process, and a chemical mechanical polishing process.

16. The method of claim 1 wherein the film is overlying a stop layer.

17. The method of claim 1 wherein the film is overlying an active region, the active region being crystalline in form and having over etch region of about 200 Angstroms or less.

18. The method of claim 1 wherein the film is overlying a copper material.

19. The method of claim 1 wherein the change in signal intensity occurs during a second time period.

20. The method of claim 19 wherein the second time period is associated with a complete processing of the film.

21. A system for in-situ monitoring of the processing of one or more films of materials using an end-point detection process, the system comprising:

a chamber, the chamber being adapted to maintain a plasma environment therein;

a susceptor coupled to the chamber, the susceptor being adapted to hold a semiconductor wafer having a film to be processed;

one or more sensors operably coupled to the chamber and adapted to collect information associated with the chamber environment during a determined time period, the information being characterized by a first signal intensity selected from an intensity of an RF signal, a light signal, a temperature signal, a pressure signal, a voltage signal, or a gas composition signal;

a process module coupled to the one or more sensors, the process module being adapted to extract a change in signal intensity from the first signal intensity, the change in signal intensity having a second signal intensity, the process module being adapted to associate the change in signal intensity at the second intensity with an end point associated with the processing of the film in the chamber environment;

whereupon the second signal intensity is about 0.25% or less of the first signal intensity.

22. The system of claim 21 wherein the second signal intensity is about 0.1% or less of the first signal intensity.