AVS 53rd International Symposium
    Manufacturing Science and Technology Thursday Sessions
       Session MS-ThA

Paper MS-ThA4
Low Coherence Optical Intereferometry and Raman Scattering Spectroscopy for Stress Tensor Measurements

Thursday, November 16, 2006, 3:00 pm, Room 2018

Session: Sensors, Metrology, and Control
Presenter: W.J. Walecki, Frontier Semiconductor
Authors: W.J. Walecki, Frontier Semiconductor
T. Azfar, Frontier Semiconductor
A. Pravdivtsev, Frontier Semiconductor
A. Koo, Frontier Semiconductor
J. Ryu, Frontier Semiconductor
Correspondent: Click to Email
In this paper we discuss accuracy and reproducibility of two techniques for metrology of stress tensor in semiconductor wafers: novel combined IR low coherence optical interefermetry@footnote 1@ allowing simultaneous measurement of wafer topography and wafers and thin film thicknesses, enabling calculation of all in plane stress tensor components, and high precision tensor resolved Micro-Raman spectroscopy. Typical micro-Raman measurements are performed in backscattered geometry. Observed stress dependent Stokes shift is related to stress in the material using specific stress tensor model typically derived on a basis of symmetry considerations,@footnote 1,2@ the usual reported reproducibility of the stress measurement of the order of 10 MPa-30 MPa,@footnote 2,3@ which corresponds to reproducibility of the Stokes shift of the order of 0.05 cm-1). By applying very large focal length grating spectrometer (effective focal length 1.34 m), and proprietary thermal drift compensation we were able to achieve thermal stability of the better than 0.0002 cm-1 / min which allows us to further improve reproducibility. We also propose two methods for recovering three and six stress tensor components in cubic crystals (such as Si/SiGe) on microscopic scale. @FootnoteText@ @footnote 1@ W.J.Walecki, A. Pravdivtsev, K. Lai, M. Santos, G. Mikhaylov, A. Koo, in ''Characterization and Metrology for ULSI Technology 2005'', edited by D.G. Seiler, et al, American Institute of Physics, p. 338- 342, 2005@footnote 2@ V. T. Srikar, A. K. Swan, M. S. Unlu, B. B. Goldberg, and S. M. Spearing, IEEE Journal of Microelectromechanical systems, Vol. 12, No. 6, December 2003, pp. 779-787@footnote 3@ Ingrid De Wolf, Chen Jian, W.Merlijn van Spengen, Optics and Lasers in Engineering 36 (2) (2001) pp. 213-223.