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16 July 2002 Spectral scatterometry for 2D trench metrology of low-K dual-damascene interconnect
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A systematic study has been conducted to evaluate accuracy and precision of spectral scatterometry used for two-dimensional (2D) characterization of trenches formed in fluorinated silicon glass (FSG). Experiments were done on short-flow dual-damascene Cu interconnect material. Trench critical dimensions (CD) obtained using KLA-Tencor's spectral scatterometer were correlated with data collected using CD atomic force microscope (AFM), CD scanning electron microscope (SEM) and transmission electron microscope (TEM). 3 major trench characteristics were analyzed: trench width, trench depth and sidewall angle. Spectral scatterometry demonstrated an excellent correlation (above 0.96) with CD AFM and SEM in tested trench width range of (80-240) nm and trench depth range of (410-450) nm. Spectral scatterometry showed acceptable correlation of 0.55 and minimal offset of 0.05 degrees with AFM in tested sidewall angle range of (87.5-89) degrees. Spectral scatterometry has demonstrated better than 1.0 nm and 0.2 degrees dynamic precision (3s) for both width and height and sidewall angle, respectively. We conclude that KLA-Tencor's SpectraCD system is capable of accurate and precise 2D characterization of FSG trenches. We recommend scatterometry as a high throughput and non-destructive metrology for trench linewidth and depth monitoring in low-K dielectric interconnect manufacturing.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Vladimir A. Ukraintsev, Mak Kulkarni, Christopher C. Baum, Karen Kirmse, Marco Guevremont, Suresh Lakkapragada, Kamal N. Bhatia, Pedro P. Herrera, and Umar K. Whitney "Spectral scatterometry for 2D trench metrology of low-K dual-damascene interconnect", Proc. SPIE 4689, Metrology, Inspection, and Process Control for Microlithography XVI, (16 July 2002);

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