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Publication Citation: Toward Accurate Linewidth Metrology Using Atomic Force Microscopy and Tip Characterization

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Author(s): Ronald G. Dixson; J Schneir; T Mcwaid; N. Sullivan; V W. Tsai; S Zaidi; S Brueck;
Title: Toward Accurate Linewidth Metrology Using Atomic Force Microscopy and Tip Characterization
Published: May 01, 1996
Abstract: As the critical dimensions of integrated circuit features decrease toward 0.18 um, feature width measurements with nanometer level accuracy will become increasingly important to the semiconductor processing industry. Atomic force microscopy (AFM) offers the promise of being able to perform such measurements. The apparent width of a feature in an AFM image is generally least affected by probe geometry near the top of the feature. Therefore, we have initially focused on this type measurement, which we call the top width. A sample of preferentially etched lines in Si was prepared for our top width measurement. The NIST calibrated atomic force microscope (C-AFM), an AFM with metrology traceable to the wavelength of light in all three axes, was used for this experiment. To achieve the smallest possible uncertainties, it is necessary to characterize the geometry of the tip and to correct the measurements of top width for the finite size of the probe. We used samples of mica with nanometer sized colloidal particles deposited on them to obtain these characterizations, and thus determined the corrected top width of the lines on the Si sample. Comparisons of these results with cross-sectional TEM measurements yielded good with uncertainties below the level of 30 nm (2sd).
Conference: Scanning Probe Metrology
Proceedings: Proceedings of SPIE, Metrology, Inspection, and Process Control for Microlithography X, Susan K. Jones, Editor
Volume: 2725
Pages: pp. 589 - 607
Location: Santa Clara, CA
Dates: March 11, 1996
Keywords: AFM,CD,metrology,SPM,standards,tip characterization
Research Areas: Metrology, Manufacturing