Chromatically corrected objective with specifically structured and arranged dioptric optical elements and projection exposure apparatus including the same
An objective having a plurality of optical elements arranged to image a pattern from an object field to an image field at an image-side numerical aperture NA>0.8 with electromagnetic radiation from a wavelength band around a wavelength lambda includes a number N of dioptric optical elements, each...
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Main Authors | , , |
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Format | Patent |
Language | English |
Published |
16.10.2018
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Subjects | |
Online Access | Get full text |
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Summary: | An objective having a plurality of optical elements arranged to image a pattern from an object field to an image field at an image-side numerical aperture NA>0.8 with electromagnetic radiation from a wavelength band around a wavelength lambda includes a number N of dioptric optical elements, each dioptric optical element i made from a transparent material having a normalized optical dispersion lambdani=ni(lambda0)-ni(lambda0+1 pm) for a wavelength variation of 1 pm from a wavelength lambda0. The objective satisfies the relation ∑ i = 1 N Delta n i ( s i - d i ) lambda 0 NA 4 <= A for any ray of an axial ray bundle originating from a field point on an optical axis in the object field, where si is a geometrical path length of a ray in an ith dioptric optical element having axial thickness di and the sum extends on all dioptric optical elements of the objective. Where A=0.2 or below, spherochromatism is sufficiently corrected. |
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Bibliography: | Application Number: US201213731775 |