Contour Metrology using Critical Dimension Atomic Force Microscopy
Ndubuisi G. Orji, Ronald G. Dixson, Boon Ping Ng, Andras Vladar, Michael T. Postek
The critical dimension atomic force microscope (CD-AFM) has been proposed as an instrument for contour measurement and verification since its capabilities are complementary to the widely used scanning electron microscope (SEM). Although data from CD-AFM are three dimensional in structure, the planar two-dimensional data required for contour metrology is not easily extracted from CD-AFM data. This is largely due to the limitations of the CD-AFM method for controlling the tip position and scanning, in which the relevant sidewall data is only obtained in one lateral axis. In order to use CD-AFM for contour metrology, the extracted profiles must include actual sidewall data from both lateral axes. Using two images acquired from orthogonal scan directions, profile extraction, and a method to combine those profiles, a technique for obtaining contours with the CD-AFM is developed. The main sources of error for this technique are described. The contours derived from CD-AFM were compared with those obtained using the SEM. Our results show that CD-AFM has the potential to make important contributions to semiconductor contour metrology.
, Dixson, R.
, , B.
, Vladar, A.
and Postek, M.
Contour Metrology using Critical Dimension Atomic Force Microscopy, Journal of Micro/Nanolithography, MEMS, and MOEMS, [online], https://doi.org/10.1117/1.JMM.15.4.044006
(Accessed February 25, 2024)