COMBINED OPTICAL METROLOGY TECHNIQUES

• US 20100277741A1
• Filed: 07/13/2010
• Published: 11/04/2010
• Est. Priority Date: 04/09/2007
• Status: Abandoned Application

• Current Assignee: Jordan Valley Semiconductors Ltd. (Bruker Corporation)
• Original Assignee: Jordan Valley Semiconductors Ltd. (Bruker Corporation)
• Inventors: Harrison, Dale A., Walsh, Phillip
• Application Number:
  US12/834,939
• Publication Number:
  US 20100277741A1
• Time in Patent Office: Days
• US Class Current: 356/445
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• 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 3/2803 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: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/4788 Diffraction for sizing particles G01N15/0205

Abstract

A method and apparatus is disclosed for using below deep ultra-violet (DUV) wavelength reflectometry for measuring properties of diffracting and/or scattering structures on semiconductor work-pieces is disclosed. The system can use polarized light in any incidence configuration, but one technique disclosed herein advantageously uses un-polarized light in a normal incidence configuration. The system thus provides enhanced optical measurement capabilities using below deep ultra-violet (DUV) radiation, while maintaining a small optical module that is easily integrated into other process tools. A further refinement utilizes an r-θ stage to further reduce the footprint.

Claims

1. A method for measuring properties of a sample, comprising:

providing an optical metrology tool that includes a first optical metrology apparatus, the first optical metrology apparatus being a first reflectometer having at least in part below deep ultra-violet light wavelengths; and

providing a second optical metrology apparatus within the optical metrology tool, the second optical metrology apparatus providing optical measurements for the sample utilizing a different optical metrology technique as compared to the first optical metrology apparatus,

wherein data sets from the first optical metrology apparatus and the second optical metrology apparatus are combined and analyzed in order to measure at least one property of the sample.

2. The method of claim 1, wherein first reflectometer and the second optical metrology apparatus operate at different wavelength ranges.

3. The method of claim 2, wherein the second optical metrology apparatus is an ellipsometer having at least in part deep ultra-violet or longer wavelengths.

4. The method of claim 1, wherein the second optical metrology apparatus is a polarized second reflectometer operating at wavelength ranges at least in part above vacuum ultra-violet wavelengths.

5. The method of claim 1, wherein the second optical metrology apparatus is a polarized reflectometer operating at wavelengths that include at least in part wavelengths below deep ultra-violet wavelengths.

6. The method of claim 1, wherein the first reflectometer is configured for normal incidence.

7. The method of claim 6, further comprising using a reduced RCW calculation for analyzing 2-D periodic structure of the sample.

8. The method of claim 6, further comprising using a group theoretic approach for analyzing 3-D periodic structure of the sample.

9. The method of claim 6, wherein incident light of the first reflectometer is un-polarized.

10. The method of claim 9, wherein the first reflectometer employs an r-θ

stage.

11. The method of claim 10, wherein a calculated reflectance of the sample is obtained from a relationship R=0.5*(R_TE+R_TM), regardless of sample rotation.