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Reflective Small Angle Electron Scattering to Characterize Nanostructures on Opaque Substrate



Lawrence H. Friedman, Wen-Li Wu, Wei-En Fu, Yunsan Chien


Feature sizes in integrated circuits (ICs) are often at the scale of 10 nm and are ever shrinking. ICs appearing in today’s computers and hand held devices are perhaps the most prominent examples. These smaller feature sizes demand equivalent advances in fast and accurate dimensional metrology for both development and manufacturing. Techniques in use and continuing to be developed include X-ray based techniques, optical scattering, and of course the electron and scanning probe microscopy techniques. Each of these techniques has their advantages and limitations. Here, the use of small angle electron beam scattering measurements in a reflection mode (RSAES) to characterize the dimensions and the shape of nanostructures on flat and opaque substrates is demonstrated using both experimental and theoretical evidence. In RSAES, focused electrons are scattered at angles smaller than 1 with the assistance of electron optics typically used in transmission electron microscopy. A proof-of-concept experiment is combined with rigorous electron reflection simulations to demonstrate the efficiency and accuracy of RSAES as a method of nondestructive measurement of shapes of features less than 10 nm in size on flat and opaque substrates.
Applied Physics Letters


diffraction, electron scattering, electron microscopy, dynamical diffraction


Friedman, L. , Wu, W. , Fu, W. and Chien, Y. (2017), Reflective Small Angle Electron Scattering to Characterize Nanostructures on Opaque Substrate, Applied Physics Letters, [online], (Accessed May 21, 2024)


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Created September 22, 2017, Updated November 10, 2018