Spectral purity filter for a multi-layer mirror, lithographic apparatus including such multi-layer mirror, method for enlarging the ratio of desired radiation and undesired radiation, and device manufacturing method
First Claim
1. A multi-layer mirror, comprising a multi-layer stack, the multi-layer stack comprising a plurality of alternating layers with a multi-layer stack top layer and a spectral filter top layer arranged on the multi-layer stack, the spectral filter top layer comprising a first spectral purity enhancement layer comprising a first material and having a layer thickness d1 and being arranged on the multi-layer stack top layer, wherein the first material is selected from SiN, Si3N4, SiO2, ZnS, Te, diamond, CsI, Se, SiC, amorphous carbon, MgF2, CaF2, TiO2, Ge, PbF2, ZrO2, BaTiO3, LiF or NaF, wherein the first material and the layer thickness d1 are selected to enlarge the ratio of radiation having a wavelength selected from a first wavelength range of 5-20 nm and radiation having a wavelength selected from a second wavelength range of 100-400 nm in a beam of radiation of a source emitting radiation with a wavelength in each wavelength range.
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Abstract
A multi-layer mirror includes on top of the multi-layer mirror a spectral purity enhancement layer, for example for application in an EUV lithographic apparatus. This spectral purity enhancement layer includes a first spectral purity enhancement layer, but between the multi-layer mirror and first spectral purity enhancement layer there may optionally be an intermediate layer or a second spectral purity enhancement layer and intermediate layer. Hence, multi-layer mirrors with the following configurations are possible: multi-layer mirror/first spectral purity enhancement layer; multi-layer mirror/intermediate layer/first spectral purity enhancement layer; and multi-layer mirror/second spectral purity enhancement layer/intermediate layer/first spectral purity enhancement layer. The spectral purity of normal incidence radiation may be enhanced, such that DUV radiation is diminished relatively stronger than EUV radiation.
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Citations
21 Claims
- 1. A multi-layer mirror, comprising a multi-layer stack, the multi-layer stack comprising a plurality of alternating layers with a multi-layer stack top layer and a spectral filter top layer arranged on the multi-layer stack, the spectral filter top layer comprising a first spectral purity enhancement layer comprising a first material and having a layer thickness d1 and being arranged on the multi-layer stack top layer, wherein the first material is selected from SiN, Si3N4, SiO2, ZnS, Te, diamond, CsI, Se, SiC, amorphous carbon, MgF2, CaF2, TiO2, Ge, PbF2, ZrO2, BaTiO3, LiF or NaF, wherein the first material and the layer thickness d1 are selected to enlarge the ratio of radiation having a wavelength selected from a first wavelength range of 5-20 nm and radiation having a wavelength selected from a second wavelength range of 100-400 nm in a beam of radiation of a source emitting radiation with a wavelength in each wavelength range.
- 16. A lithographic apparatus comprising one or more multi-layer mirrors comprising a multi-layer stack, the multi-layer stack comprising a plurality of alternating layers with a multi-layer stack top layer and a spectral filter top layer arranged on the multi-layer stack, the spectral filter top layer comprising a first spectral purity enhancement layer comprising a first material and having a layer thickness d1 and being arranged on the multi-layer stack top layer, wherein the first material is selected from SiN, Si3N4, SiO2, ZnS, Te, diamond, CsI, Se, SiC, amorphous carbon, MgF2, CaF2, TiO2, Ge, PbF2, ZrO2, BaTiO3, LiF or NaF, and the thickness d1 is between 0.5 and 30 nm, wherein the first material and the layer thickness d1 are selected to enlarge the ratio of radiation having a wavelength selected from a first wavelength range of 5-20 nm and radiation having a wavelength selected from a second wavelength range of 100-400 nm in a beam of radiation of a source emitting radiation with a wavelength in each wavelength range.
- 18. A method, comprising reflecting a beam of radiation with a multi-layer mirror, the multi-layer mirror comprising a multi-layer stack, the multi-layer stack comprising a plurality of alternating layers with a multi-layer stack top layer and a spectral filter top layer arranged on the multi-layer stack, the spectral filter top layer comprising a first spectral purity enhancement layer comprising a first material and having a layer thickness d1 and being arranged on the multi-layer stack top layer, wherein the first material is selected from SiN, Si3N4, SiO2, ZnS, Te, diamond, CsI, Se, SiC, amorphous carbon, MgF2, CaF2, TiO2, Ge, PbF2, ZrO2, BaTiO3, LiF or NaF, and the thickness d1 is between 0.5 and 30 nm, wherein the first material and the layer thickness d1 are selected to enlarge the ratio of radiation having a wavelength selected from a first wavelength range of 5-20 nm and radiation having a wavelength selected from a second wavelength range of 100-400 nm in the beam of radiation, the beam having radiation with a wavelength in each wavelength range.
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21. A device manufacturing method, comprising:
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providing a beam of radiation; patterning the beam of radiation; projecting the patterned beam of radiation onto a target portion of a substrate; and reflecting at least part of the beam of radiation on a multi-layer mirror, the multi-layer mirror comprising a multi-layer stack, the multi-layer stack comprising a plurality of alternating layers with a multi-layer stack top layer and a spectral filter top layer arranged on the multi-layer stack, the spectral filter top layer comprising a first spectral purity enhancement layer comprising a first material and having a layer thickness d1 and being arranged on the multi-layer stack top layer, wherein the first material is selected from SiN, Si3N4, SiO2, ZnS, Te, diamond, CsI, Se, SiC, amorphous carbon, MgF2, CaF2, TiO2, Ge, PbF2, ZrO2, BaTiO3, LiF or NaF, and the layer thickness d1 is between 0.5 and 30 nm, wherein the first material and the layer thickness d1 are selected to enlarge the ratio of radiation having a wavelength selected from a first wavelength range of 5-20 nm and radiation having a wavelength selected from a second wavelength range of 100-400 nm in the beam of radiation, the beam having radiation with a wavelength in each wavelength range.
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Specification