Monochromator mirror for the EUV-spectral range
First Claim
1. A monochromator mirror for the EUV spectral range having a layer arrangement applied to a substrate and which has a sequence of individual layers, wherein the layer arrangement has a periodic sequence of two individual layers A and B of different materials forming one period with the period thickness d and having the particular layer thickness dA and dB, so that the following applies:
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0.97(dA+dB)≦
d≦
(dA+dB)1.03 where
(nAdA+nBdB)*cos(θ
)=m*λ
/2,wherein nA and nB are the real parts of the complex refractive indices of the materials of the individual layers A and B, m is a whole number representing the order of Bragg reflection greater than or equal to 2 and λ
is the wavelength of the incident radiation and θ
is the angle of incidence of the incident radiation, and wherein also the following applies for the layer thickness ratio ┌
=dA/d;
┌
<
0.8/m;
and wherein the reduction of the half width of mirror reflection when using a Bragg reflection of the 2nd order (m=2) with respect to the half width of the mirror reflection when using a Bragg reflection of the 1st order (m=1) is about the factor 2.
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Accused Products
Abstract
The invention relates to a monochromator mirror for the EUV-spectral range, provided with a layer arrangement placed on a substrate, comprising a periodic sequence of two individual layers (A, B) made of different material forming a period having a thickness d in the form of a spacer-layer or an absorber-layer, whereby the reflectivity of the second or a higher Bragg-order is used. Said thickness d has a dimensional deviation of a maximum of 3% and the ratio of the layer thickness of the absorber-layer to the period thickness is smaller than the ratio of 0.8 of the used order of the Bragg-Reflexion.
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Citations
5 Claims
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1. A monochromator mirror for the EUV spectral range having a layer arrangement applied to a substrate and which has a sequence of individual layers, wherein the layer arrangement has a periodic sequence of two individual layers A and B of different materials forming one period with the period thickness d and having the particular layer thickness dA and dB, so that the following applies:
-
0.97(dA+dB)≦
d≦
(dA+dB)1.03 where
(nAdA+nBdB)*cos(θ
)=m*λ
/2,wherein nA and nB are the real parts of the complex refractive indices of the materials of the individual layers A and B, m is a whole number representing the order of Bragg reflection greater than or equal to 2 and λ
is the wavelength of the incident radiation and θ
is the angle of incidence of the incident radiation, and wherein also the following applies for the layer thickness ratio ┌
=dA/d;
┌
<
0.8/m;
and wherein the reduction of the half width of mirror reflection when using a Bragg reflection of the 2nd order (m=2) with respect to the half width of the mirror reflection when using a Bragg reflection of the 1st order (m=1) is about the factor 2. - View Dependent Claims (2, 3, 4, 5)
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Specification