Claims
- 1. An optical measurement system for evaluating a substrate, the system comprising:
a laser for generating an intensity-stabilized light beam, a static polarizing element for polarizing the light beam emanating from the laser to provide stabilized polarized light, an optical element for directing the stabilized polarized light to a particular location on the substrate, a detection system for measuring the light beam after interaction with the particular location on the substrate, the detection system including
a static beam splitting element for splitting the light beam after interaction with the particular location on the substrate into s-polarized light and p-polarized light, a first sensor for measuring amplitude of the s-polarized light, a second sensor for measuring amplitude of the p-polarized light, and a control system for analyzing the measured amplitude of the s-polarized and p-polarized light to determine changes in the substrate.
- 2. The optical measurement system of claim 1, wherein the laser is a fiber-coupled laser diode.
- 3. The optical measurement system of claim 1, wherein the laser is a laser diode.
- 4. The optical measurement system of claim 1, wherein the static polarizing element is a retarder.
- 5. The optical measurement system of claim 4, wherein the retarder is a quarter-wave plate.
- 6. The optical measurement system of claim 4, wherein the retarder is a liquid crystal variable retarder (LCVR).
- 7. The optical measurement system of claim 1, wherein the optical element is an objective lens.
- 8. The optical measurement system of claim 1, wherein the static beam splitting element is a polarizing beam splitter.
- 9. The optical measurement system of claim 1, wherein the first sensor and the second sensor are photo-diodes.
- 10. The optical measurement system of claim 1, further comprising a light source feedback system for controlling and stabilizing the intensity of the light beam.
- 11. The optical measurement system of claim 10, wherein the light source feedback system includes
a photo-diode for measuring the intensity of the light beam and generating an output signal based on the measured intensity, and a light source controller coupled to the means for generating a light source and the photo-diode, the light source controller controlling and stabilizing the light beam based on the output signal received from the photo-diode.
- 12. The optical measurement system of claim 11, further comprising a non-polarizing beam splitter for directing a portion of the light beam to the photo-diode.
- 13. The optical measurement of claim 1, further comprising a light source feedback system for monitoring the intensity of the light beam.
- 14. The optical measurement system of claim 13, wherein the light source feedback system includes a photodiode for measuring the intensity of the light beam.
- 15. The optical measurement system of claim 1, further comprising a controllable translatable assembly for moving the polarized light beam across at least a portion of the substrate.
- 16. The optical measurement system of claim 15, further comprising a position indicating means for determining the particular location on the substrate upon which the polarized light beam impinges.
- 17. The optical measurement system of claim 16, wherein the position indicating means is a 512 position shaft encoder.
- 18. The optical measurement system of claim 17, wherein the control system is coupled to the position indicating means, the first sensor for measuring amplitude of s-polarized light, and the second sensor for measuring amplitude of p-polarized light, the control system compiling a data set correlating the measured amplitude of the s-polarized light and the p-polarized light with the particular locations on the substrate upon which the light beam impinges.
- 19. The optical measurement system of claim 18, wherein the control system includes memory storage means for storing the data set.
- 20. The optical measurement system of claim 1, wherein the polarizing element is an elliptical polarizer for elliptically polarizing the light beam.
- 21. The optical measurement system of claim 1, wherein the polarizing element is a linear polarizer for linearly polarizing the light beam.
- 22. The optical measurement system of claim 1, wherein the polarizing element is a circular polarizer for circularly polarizing the light beam.
- 23. The optical measurement system of claim 1, further comprising a system for collecting and measuring scattered light reflected from the substrate.
- 24. The optical measurement system of claim 23, wherein the system for collecting and measuring scattered light includes an integrating sphere.
- 25. A method of evaluating a substrate comprising the steps of
generating an initial map of at least a portion of the substrate by:
generating an intensity-stabilized laser light beam, staticly polarizing the light beam to form a stabilized polarized light beam, directing the polarized light beam to a measurement point on the substrate, separating the polarized light beam after interaction with the particular location on the substrate into a set of two orthogonally polarized light beams, measuring the amplitude of each of the orthogonally polarized light beams, compiling a data set by synchronizing the measured amplitude of each set of orthogonally polarized light beams with the location of each corresponding measurement point on the substrate; generating a second map of the substrate; and determining changes in the substrate by comparing the initial map with the second map.
- 26. The method of claim 25, wherein the step of polarizing light beam includes the step of linearly polarizing the light beam.
- 27. The method of claim 25, wherein the step of polarizing light beam includes the step of elliptically polarizing the light beam.
- 28. The method of claim 25, wherein the step of polarizing light beam includes the step of circularly polarizing the light beam.
- 29. An optical measurement system for evaluating a substrate, the system comprising:
an intensity stabilized light source configured to generate a stabilized light beam, a static polarizing element for polarizing the light beam emanating from the light generating means to provide stabilized polarized light, an optical element for focusing the stabilized polarized light at a particular location on the substrate, a detection system for measuring the light beam reflected from the particular location on the substrate, the detection system including
means for staticly splitting the light beam reflected from the particular location on the substrate into s-polarized light and p-polarized light, a first sensor for measuring amplitude of the s-polarized light, a second sensor for measuring amplitude of the p-polarized light, and a CPU for analyzing the measured amplitude of the s-polarized light and the p-polarized light to determine changes in the substrate.
- 30. An optical measurement system for evaluating a substrate, the system comprising:
an intensity stabilized light source configured to generate a stabilized light beam, a polarizing element for polarizing the light beam emanating from the light source to provide a polarized light beam, an optical system for directing the polarized light beam to a particular location on the substrate, a controllable translatable assembly for moving the polarized light beam across at least a portion of the substrate such that the polarized light beam impinges upon multiple locations on the substrate, a position indicating means for determining the particular location on the substrate upon which the polarized light beam impinges, a detection system configured to evaluate the light beam after interaction with the particular locations on the substrate upon which the polarized light beam impinges, the detection system including
a polarization analyzing element for separating the light from the particular locations on the substrate into s-polarized light and p-polarized light, a first optical sensor measuring amplitude of the s-polarized light, a second optical sensor measuring amplitude of the p-polarized light, and a third optical sensor measuring phase difference between the s-polarized light and the p-polarized light, and a control system configured to compile a data set correlating the measured amplitude of the s-polarized light, the p-polarized light, and the measured phase difference with the particular location on the substrate upon which the polarized light beam impinges for determining changes in the substrate.
- 31. The optical measurement system of claim 30, wherein a light source feedback system controls and stabilizes the intensity of the light beam.
- 32. The optical measurement system of claim 31, wherein the light source feedback system includes
a photo-diode for measuring the intensity of the light beam and generating an output signal based on the measured intensity, and a light source controller coupled to the light source and the photo-diode, the light source controller controlling and stabilizing the light beam based on the output signal received from the photo-diode.
- 33. The optical measurement system of claim 32, further comprising a non-polarizing beam splitter for directing a portion of the light beam to the photo-diode.
- 34. The optical measurement system of claim 30, further comprising a system for measuring scattered light after interaction of the light beam with the substrate.
- 35. The optical measurement system of claim 34, wherein the system for collecting and measuring scattered light includes an integrating sphere.
- 36. The optical measurement system of claim 1, wherein the detection system further includes a non-polarizing beam splitter directing a portion of the light beam after interaction with the substrate to the third optical sensor.
- 37. The optical measurement system of claim 1, wherein the polarization analyzing element is a polarizing beam-splitter.
- 38. The optical measurement of claim 30, further comprising a light source monitoring system for monitoring the intensity of the light beam.
- 39. A method of evaluating a substrate comprising the steps of
generating an intensity stabilized light beam; polarizing the light beam to form a polarized light beam, directing the polarized light beam to a particular location on the substrate, separating the polarized light beam after interaction with the particular location on the substrate into two orthogonally polarized light beams, measuring the amplitude of each of the orthogonally polarized light beams, measuring the phase difference between the two orthogonally polarized light beams, and analyzing the measured amplitude of each of the two orthogonally polarized light beams and the measured phase difference between the two orthogonally polarized light beams to determine changes in the substrate.
- 40. The method of claim 39, further comprising the steps of
monitoring the intensity of the light beam, and controlling and stabilizing the intensity of the light beam based on the monitored light intensity.
- 41. The method of claim 39, further comprising the step of measuring scattered light after the light beam interacts with the substrate and wherein the step of analyzing includes analyzing the measured scattered light to determine changes in the substrate.
REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent application Ser. No. 09/153,646, filed Sep. 15, 1998, which is a continuation-in-part of U.S. patent application Ser. No. 09/090,434 filed Jun. 4, 1998, which claims the benefit of U.S. Provisional Application No. 60/059,498, filed on Sep. 22, 1997. Each of the above-referenced patent applications is incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60059498 |
Sep 1997 |
US |
Continuations (2)
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Number |
Date |
Country |
Parent |
09441253 |
Nov 1999 |
US |
Child |
10036062 |
Oct 2001 |
US |
Parent |
09153646 |
Sep 1998 |
US |
Child |
09441253 |
Nov 1999 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09090434 |
Jun 1998 |
US |
Child |
09153646 |
Sep 1998 |
US |