Optics: measuring and testing – By polarized light examination – Of surface reflection
Reexamination Certificate
1999-12-14
2001-11-27
Pham, Hoa Q. (Department: 2877)
Optics: measuring and testing
By polarized light examination
Of surface reflection
C356S365000, C356S366000, C356S367000, C250S225000
Reexamination Certificate
active
06323947
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the use of averaging of + and − values of a parameter in mechanical-optical metrology apparatus to establish an assigned value for use in the apparatus in highly sensitive applications and in particular to the establishing of an averaged value of the angle of incidence of a, to be reflected light beam, in ellipsometry.
BACKGROUND OF THE INVENTION AND RELATION TO THE PRIOR ART
Ellipsometry metrology involving apparatus in which samples to be studied are mechanically positionable and changes in reflected light from the samples is used in feature identification or characterization of the surface and bulk aspects of solid materials is becoming of increasing necessity as the dimensions being studied become smaller. The terminology “sample” is used for explanation simplicity. In metrology, the apparatus and analytical principles involved are useable in single, batch and on line types of operation in arrangements where an incident beam of polarized light is reflected from a sample under study and differences in the polarization of the reflected light that are produced by the reflection from the sample provide the measured quantities. The metrology operations require tedious data taking involving calibrated interaction of mechanical and optical components. One of the most influential parameters is the angle of incidence of the beam of polarized light, when the beam reflects from the sample. Any error in the value assumed in the data taking for the angle of incidence, especially where small dimensions are involved, is frequently only identified after considerable apparatus calibration time and effort. There are needs in the ellipsometry metrology art for ways of providing accurate assumed values for all parameters and in the case of the angle of incidence the need is particularly acute.
SUMMARY OF THE INVENTION
Improvements in accuracy and sensitivity in mechanical-optical apparatus are achieved through the use of a value for angle of incidence that is an average of positive and negative values for different arrangements of the metrology apparatus. In the ellipsometry type of metrology the average value for angle of incidence is established by using one of a reversal of light beam direction, the providing of a separate light beam mounting arm and the mechanical rotation of the sample.
REFERENCES:
patent: 3880524 (1975-04-01), Dill et al.
patent: 4053232 (1977-10-01), Dill et al.
patent: 4332833 (1982-06-01), Aspnes et al.
patent: 4653924 (1987-03-01), Itonaga et al.
patent: 4672196 (1987-06-01), Canino
patent: 4762414 (1988-08-01), Grego
patent: 4837603 (1989-06-01), Hayashi
patent: 5091320 (1992-02-01), Aspnes et al.
patent: 5277747 (1994-01-01), Aspnes et al.
patent: 5526117 (1996-06-01), Wielisch et al.
patent: 5595916 (1997-01-01), Fujimura et al.
patent: 5608526 (1997-03-01), Piwonma-Corle et al.
patent: 6222199 (2001-04-01), Freeouf
patent: 63-12906 (1988-01-01), None
patent: 6423105 (1989-01-01), None
patent: 5-263244 (1993-10-01), None
R. L. Johnson et al, “Spectroscopic Ellipsometry With Synchrotron Radiation”, Review of Scientific Inst. vol. 60(7) Jul. 1989 pp. 2209-2212.
Germer Et Al, “Plarization of Out-of-Plane Scattering from Microrough Silicon”, Optics Letters, vol. 22 (17) Sep. 1997 pp. 1284-1286.
P.S. Hauge, “Recent Developments in Instrumentation in Ellipsometry,” Surface Science, vol. 96, No. 1-3, 1980, pp. 108-140.
Henneth K. Ellis, “Polarimetric Bidirectional Reflectance Distribution Function of Glossy Coatings”, J. Opt. Soc. Am., vol. 13, No. 8, Aug. 1996 pp. 1758-1762.
Deumié Et Al, “Ellipsometry of Light Scattering from Multilayer Coatings”, Applied Optics, vol. 35 No. 28, Oct. 96, pp. 5600-5608.
U. Rossow Et Al, Interpretation of Surface-Induced Optical Anisotropy of Clean, Hydrogenated, and Oxiidized Vional Silicon, Surfaces Investigated by Reflectance Difference Spectroscopy, J. Vac. Sci. Tech. B, 14, 4, Jul./Aug. 1996 pp. 3070-3074.
John L.Freeouf, “Application of Spectroscopic Ellipsometry to Complex Samples”, App. Phys. Ltrs. 53,(24), Dec. 88 pp. 2426-2428.
D.E. Aspnes, Analysis of Semiconductor Materials and Structures by Spectroellipsometry S.P.I.E. vol. 946, 1988 pp. 84-97.
Sales Brochure, J.A.Woolam Co., Variable Angle Spectroscopic Ellipsometers, 8 pages.
Sales Brochure, “Infrared Spectroscopic Ellipsometer SE900”, Sentech, Instruments, 4 pages.
T.E Faber and N.V. Smith, “Optical Measurements on Liquid Metals Using a New Ellipsometer” Journal of the Optical Society of America, vol. 58, No. 1, Jan. 1968, pp. 102-108.
Bertucci Et Al, “Systematic Errors in Fixed Polarizer, Rotating Polarizer, Sample, Fixed Analyzer, Spectroscopic Ellipsometry,” Thin Solid Films 313-314 (1998) 73-78.
Azzam et al, “Analysis of Systematic Errors in Rotating-Analyzer Ellipsometer”Journal of the Optical Society of America, vol. 64, No. 11, Nov. 1974, pp. 1459-1469.
Interface Studies Corporation
Nguyen Sang Hoang
Pham Hoa Q.
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