Broad band referencing reflectometer

• US 8,014,000 B2
• Filed: 11/03/2009
• Issued: 09/06/2011
• Est. Priority Date: 01/16/2003
• Status: Active Grant

• Current Assignee: Bruker Technologies Ltd. (Bruker Corporation)
• Original Assignee: Jordan Valley Semiconductors Ltd. (Bruker Corporation)
• Inventors: Harrison, Dale A.
• Primary Examiner(s): AKANBI, ISIAKA O
• Application Number:
  US12/590,151
• Publication Number:
  US 20100051822A1
• Time in Patent Office: 672 Days
• Field of Search: 356/445, 356/328, 250/372, 250/339, 250/2
• US Class Current: 356/445
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0232 using shutters
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/0286 Constructional arrangements for compensating for fluctuations caused by temperature, humidity or pressure, or using cooling or temperature stabilization of parts of the device; Controlling the atmosphere inside a spectrometer, e.g. vacuum
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/08 Beam switching arrangements
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01J 3/4531 Devices without moving parts
• CPC Class Codes: G01N 2021/335 Vacuum UV
• CPC Class Codes: G01N 21/211 Ellipsometry optical thickness measurement G01B11/06
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• CPC Class Codes: G01N 21/55 : Specular reflectivity
• CPC Class Codes: G01N 21/9501 : Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10

Abstract

A spectroscopy system is provided which is optimized for operation in the VUV region and capable of performing well in the DUV-NIR region. Additionally, the system incorporates an optical module which presents selectable sources and detectors optimized for use in the VUV and DUV-NIR. As well, the optical module provides common delivery and collection optics to enable measurements in both spectral regions to be collected using similar spot properties. The module also provides a means of quickly referencing measured data so as to ensure that highly repeatable results are achieved. The module further provides a controlled environment between the VUV source, sample chamber and VUV detector which acts to limit in a repeatable manner the absorption of VUV photons. The use of broad band data sets which encompass VUV wavelengths, in addition to the DUV-NIR wavelengths enables a greater variety of materials to be meaningfully characterized. Array based detection instrumentation may be exploited to permit the simultaneous collection of larger wavelength regions.

Claims

1. A method for analyzing a scattering or diffracting structure that includes a pattern having a pitch, the method comprising:

providing a below deep ultra-violet (DUV) wavelength reflectometer configured for normal incidence operation and having a light source that provides at least below DUV wavelength light, including vacuum ultra-violet (VUV) wavelengths at and below the pitch of the pattern;

obtaining reflectance data from the scattering or diffracting structure, including reflectance data for the VUV wavelengths; and

utilizing the reflectance data to obtain dimension information of the pattern.

2. The method of claim 1, further comprising utilizing referencing to account for system and environmental changes to adjust reflectance data obtained through use of the reflectometer.

3. The method of claim 1, wherein the reflectometer utilizes a non-polarizing optical path such that a polarization independent measurement may be obtained.

4. The method of claim 1, wherein the below DUV wavelength light is non-polarized at a point in an optical path of the reflectometer at which the scattering or diffracting structure is located.

5. The method of claim 1, wherein the dimension information comprises at least one of line width, sidewall angle, line height, trench depth, trench width and film thickness.

6. The method of claim 1, wherein scatterometry techniques are utilize to determine the dimension information.

7. The method of claim 6, wherein rigorous coupled wave analysis techniques are utilized to determine the dimension information.

8. A method for analyzing a scattering or diffracting structure, comprising:

providing a below deep ultra-violet (DUV) wavelength referencing reflectometer, comprising a source beam channel configured for normal incidence operation and having a non-polarizing optical system that provides at least below deep ultra-violet wavelength light, and comprising a reference beam channel that is balanced with the source beam channel; and

utilizing scatterometry techniques for obtaining dimensional information of the scattering or diffracting structure.

9. The method of claim 8, further comprising utilizing referencing to account for system and environmental changes to adjust reflectance data obtained through use of the reflectometer.

10. The method of claim 9, wherein the dimension information comprises at least one of line width, sidewall angle, line height, trench depth, trench width and film thickness.

11. The method of claim 8, wherein the dimension information comprises at least one of line width, sidewall angle, line height, trench depth, trench width and film thickness.

12. The method of claim 8, wherein rigorous coupled wave analysis techniques are utilized to determine the dimension information.

13. A scatterometry method to determine dimensional information of a patterned structure having a pitch, the method comprising:

providing a reflectometer that utilizes at least in part below deep ultra-violet (DUV) wavelength light, including vacuum ultra-violet (VUV) wavelengths at and below the pitch;

obtaining reflectance data from the scattering or diffracting structure, including reflectance data for at least some of the VUV wavelengths; and

utilizing scatterometry techniques to analyze the reflectance data to obtain dimension information of the patterned structure.

14. The method of claim 13, wherein the reflectometer utilizes a non-polarizing optical path such that a polarization independent measurement may be obtained.

15. The method of claim 13, wherein the below DUV wavelength light is non-polarized at a point in an optical path of the reflectometer at which the patterned structure is located.

16. The method of claim 13, wherein the dimension information comprises at least one of line width, sidewall angle, line height, trench depth, trench width and film thickness.

17. The method of claim 13, wherein the scatterometry techniques include rigorous coupled wave analysis techniques.

18. A method for analyzing a scattering or diffracting structure, comprising:

providing a below deep ultra-violet (DUV) wavelength reflectometer configured for normal incidence operation and having a light source that provides at least below DUV wavelength light;

obtaining reflectance data from the scattering or diffracting structure, including reflectance data for wavelengths below DUV wavelengths; and

utilizing the reflectance data to obtain dimension information of the scattering or diffracting structure including at least one dimension of 20 Å

or less.

19. The method of claim 18, wherein utilizing the reflectance data comprises using a balanced reference beam channel to account for system and environmental changes to adjust the reflectance data.

20. The method of claim 18, wherein utilizing the reflectance data comprises applying scatterometry techniques to determine the dimension information.