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Proceedings Paper

Rapid x-ray reflectivity (XRR) characterization and process monitoring of multilayer Ta/Al2O3/Ta/SiO2/Si
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Paper Abstract

We have developed a rapid XRR system that is capable of acquiring the reflectivity data in the angular range of 0.1 - 1.6 degree in less than 20 sec. The data were analyzed to obtain the thickness, density and roughness of the film of interest in a few seconds. The system consisted of an x-ray source with a tungsten target and a Si monochromator, a sample stage, and a 1024-pixel photo-diode array. The system was used to characterize the multiple film stack of Ta/Al2O3/Ta/SiO2/Si. The Ta and Al films were sputtered onto the SiO2/Si substrate and the Al was oxidized to form the film of Al2O3. The thickness of the Ta layers was about 100 angstrom while the thickness of Al2O3 varied from 40 angstrom to 200 angstrom. The XRR sensitivity to parameters such as thickness, density, and roughness of the Ta and Al2O3 layer was also studied. We found that the XRR can measure the thickness and density of each layer with a standard deviation less than 0.5% and 1.5% of the target thickness and density, respectively. The roughness was found to have a standard deviation better than 1 angstrom. We also found that the density of the film of Al2O3 varied from 2.7 - 4.0 g/cm3, indicating that the stoichiometry of the Al2O3 films ranged from the non-oxidized pure Al to the fully oxidized Al2O3. The information of the thickness, density and roughness of each of the Ta and Al2O3 films from XRR is particularly useful to nondestructively monitor the thin film deposit conditions in real time.

Paper Details

Date Published: 10 December 2001
PDF: 9 pages
Proc. SPIE 4449, Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries II, (10 December 2001); doi: 10.1117/12.450101
Show Author Affiliations
JingMin Leng, Therma-Wave, Inc. (United States)
Jon L. Opsal, Therma-Wave, Inc. (United States)

Published in SPIE Proceedings Vol. 4449:
Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries II
Angela Duparre; Bhanwar Singh, Editor(s)

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