OPTICAL ELEMENT
2 Assignments
0 Petitions
Accused Products
Abstract
In order to make possible both good laser resistance and good antireflection properties, an optical element, in particular for UV lithography, comprising a substrate and a coating on the substrate having at least four layers, is proposed, wherein
- a first layer comprising a low refractive index inorganic fluoride compound is arranged on the substrate,
- a layer comprising an inorganic oxide-containing compound is arranged as a layer the most distant from the substrate, and
- at least two further layers each comprising an inorganic fluoride compound or an inorganic oxide-containing compound are arranged alternately between the first and the most distant layers.
14 Citations
38 Claims
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1-18. -18. (canceled)
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19. An optical element, comprising:
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a substrate comprising a fluoride; and a coating supported by the substrate, wherein; the coating comprises, in order moving away from the substrate, a first layer, a second layer, a third layer, and a fourth layer; the first layer comprises an inorganic fluoride having a refractive index at a wavelength in the ultraviolet range that is less than a refractive index of calcium fluoride at the wavelength in the ultraviolet range; the second layer comprises an inorganic oxide; the third layer comprises an inorganic fluoride; the fourth layer comprises an inorganic oxide; the first layer is in contact with the substrate; the fourth layer is in contact with the surroundings of the optical element; the second layer is in direct contact with the first layer; and the second layer is in direct contact with the third layer. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An optical element, comprising:
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a substrate comprising a fluoride; and a coating supported by the substrate, wherein; the coating comprises, in order moving away from the substrate, a first layer, a second layer, a third layer, and a fourth layer; the first layer comprises an inorganic fluoride having a refractive index at a wavelength in the ultraviolet range that is less than a refractive index of calcium fluoride at the wavelength in the ultraviolet range; the second layer comprises and inorganic oxide; the third layer comprises an inorganic fluoride; the fourth layer comprises an inorganic oxide; the first layer is in contact with the substrate; the fourth layer is in contact with the surroundings of the optical element; and the fourth layer is in direct contact with the third layer. - View Dependent Claims (38)
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Specification