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Tip on Tip Imaging and Self-Consistent Calibration using Critical Dimension Atomic Force Microscopy



Ronald G. Dixson


Critical dimension atomic force microscopy (CD-AFM) is a measurement technique that uses flared tips and two-dimensional surface sensing to enable scanning of features with near-vertical sidewalls. A major source of uncertainty in metrology with CD-AFM is the calibration uncertainty of the tip width. Standards for traceable tip width calibration have been developed both by national metrology institutes (NMIs) such as NIST and commercial suppliers. The NIST standard of this type is the single crystal critical dimension reference material (SCCDRM). Expanded uncertainties (k = 2) on the order of 1 nm were achieved, ultimately traceable through HRTEM and the silicon lattice constant. This paper describes work on a self- consistency method of CD-AFM tip calibration. Due to the requirement for tip on tip imaging and challenges associated with this, the application of such methods in AFM metrology has been relatively limited. Results that are in agreement with the prior NIST SCCDRM were obtained, comparable levels of uncertainty should be achievable. While the self-consistent approach is unlikely to supplant TEM cross-sections and the use of well-characterized standards, it may have value as a supporting method or for validation of a prior result.
Journal of Micro/Nanolithography, MEMS, and MOEMS


CD-AFM, self-consistent calibration, linewidth, metrology


Dixson, R. (2017), Tip on Tip Imaging and Self-Consistent Calibration using Critical Dimension Atomic Force Microscopy, Journal of Micro/Nanolithography, MEMS, and MOEMS (Accessed April 17, 2024)
Created June 30, 2017