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TSOM Method for Nanoelectronics Dimensional Metrology



Ravikiran Attota


Through-focus scanning optical microscopy (TSOM) is a relatively new method that transforms conventional optical microscopes into truly three-dimensional metrology tools for nanoscale to microscale dimensional analysis. TSOM achieves this by acquiring and analyzing a set of optical images collected at various focus positions going through focus (from above-focus to under-focus). The measurement resolution is comparable to what is possible with typical light scatterometry, scanning electron microscopy (SEM) and atomic force microscopy (AFM). TSOM method is able to identify nanometer scale difference, type of the difference and magnitude of the difference between two nano/micro scale targets using a conventional optical microscope with visible wavelength illumination. Numerous industries could benefit from the TSOM method —such as the semiconductor industry, MEMS, NEMS, biotechnology, nanomanufacturing, data storage, and photonics. The method is relatively simple and inexpensive, has a high throughput, provides nanoscale sensitivity for 3D measurements and could enable significant savings and yield improvements in nanometrology and nanomanufacturing. Potential applications are demonstrated using experiments and simulations.
Proceedings Title
Frontiers of Characterization and Metrology for Nanoelectronics
Conference Dates
May 23-26, 2011
Conference Location


Nanometrology, nanomanufacturing, dimensional metrology, defect analysis, process control, critical dimensions, optical microscope, through-focus, MEMS, NEMS, overlay, TSV, photonics, nanodots, nanowires


Attota, R. (2011), TSOM Method for Nanoelectronics Dimensional Metrology, Frontiers of Characterization and Metrology for Nanoelectronics , Grenoble, -1, [online], (Accessed May 30, 2024)


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Created November 18, 2011, Updated February 19, 2017