PATENT CLAIM ANALYSIS

Application Number: 16416775
Application Type: Utility
Filing Date: 2019-05
Publication Date: 2019-09
Patent Classification: ["702", "104000"]

Abstract:
Optical metrology is used to calibrate the plane-of-incidence (POI) azimuth error by determining and correcting an azimuth angle offset. The azimuth angle offset may be determined by measuring at least a partial Mueller matrix from a calibration grating on a sample held on a stage for a plurality of POI azimuth angles. An axis of symmetry is determined for a curve describing a value of a Mueller matrix element with respect to POI azimuth angle, for each desired wavelength and each desired Mueller matrix element. The axis of symmetry may then be used to determine the azimuth angle offset, e.g., by determining a mean, median or average of all, or a filtered subset, of the axes of symmetry. If desired, an axis of symmetry may be determined for data sets other than Mueller matrix elements, such as Fourier coefficients of measured signals.

Claim (Index 1):
A method of calibration and correction of an azimuth angle offset of an optical metrology tool, the optical metrology tool having an optical system that produces a beam of light having a plane-of-incidence (POI), wherein the azimuth angle offset is between the POI and an orientation of a calibration grating on a sample at a nominal orientation with respect to the POI, the method comprising:\n loading the sample with the calibration grating on a stage of the optical metrology tool, wherein there is an azimuth angle offset between the POI of the optical metrology tool and the orientation of the calibration grating on the sample at the nominal orientation with respect to the POI is unknown; rotating the stage that holds the sample to a plurality of POI azimuth angles; measuring with the optical metrology tool signals from the calibration grating at each of the plurality of POI azimuth angles; determining Fourier coefficients of the signals measured by the optical metrology device from the calibration grating on the sample at each of the plurality of POI azimuth angles, wherein each of the Fourier coefficients of the signals comprises a value that varies for the different POI azimuth angles; determining an axis of symmetry for a curve describing the Fourier coefficients at the different POI azimuth angles, wherein the axis of symmetry for the curve is an azimuth angle about which the values of the Fourier coefficients are symmetrically arranged and at which a mirror symmetry plane of the calibration grating is aligned with the POI; using the axis of symmetry to determine the azimuth angle offset between the POI of the optical metrology tool and the orientation of the calibration grating at the nominal orientation with respect to the POI; and correcting the azimuth angle offset between the POI and the orientation of the calibration grating on the sample on the stage of the optical metrology tool using the determined azimuth angle offset.

Metadata:
- Claim Count in Document: 37.0
- Percentile: 100.0
- Lexical Diversity: 1.98734
- Patent Class: 702.0
- Transitional Phrase Type: open
- Component Type: 1
- Foreign Priority: False
- Related Applications: ['13831456', '12357294', '15789992', '12169331', '12696974']

Analysis Scores:
- 35 USC 101 Eligibility (BERT): 0.1967980718010813
- 35 USC 102 Novelty (BERT): 0.66656187798456
- Combined Prediction Score: 0.2437744524194292
- Mean Citation Score: 334.156622
- Max Citation Score: 656.8438
- Similarity Product: 653.7860331769705

Labels:
- Claim Label 101: 1
- Claim Label 102: 1
- Claim Label 103: 0
- Claim Label 112: 1
- Combined Label: 1
- Label 101 Adjusted: 1

Dataset: test