Amin Cheraghi Shirazi Jan 2013 CAMTEC Nanofabrication Workshop SEM 2 Lens Aberrations Spherical Aberration Chromatic Aberration Diffraction Astigmatism 3 Spherical Aberration ID: 775174
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Slide1
SEM Lens Aberration:Astigmatism
Amin
Cheraghi
Shirazi
Jan. 2013
CAMTEC Nanofabrication Workshop
Slide2SEM
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Slide3Lens Aberrations
Spherical Aberration Chromatic Aberration Diffraction Astigmatism
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Slide4Spherical Aberration
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Slide5Chromatic Aberration
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Slide6Diffraction
Electrons wavelengths being out of phaseLens will focus electrons of different phase to a different pointMonochromatic and Coherent
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Slide7Astigmatism
Non-uniform magnetic field
No perfect cylindrical symmetry
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Slide8Astigmatism Other Reasons
Micro-structural inhomogeneitiesLocal variations in the magnetic field strengthNot precisely centered aperturesApertures contamination
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Slide9Astigmatism Correction
Stigmatorsboth in the illumination and imaging system
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Slide10Thank You!!!
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