JP5431900B2 - X-ray condenser lens - Google Patents

Description

  The present invention relates to an X-ray condensing device, and more particularly to an X-ray condensing lens that condenses light using a waveguide, a phase shift zone, and an X-ray shielding structure in combination.

  In recent years, with the progress of nanotechnology development, structural evaluation of materials at the nanometer level is required. There are scanning microscopes, electron microscopes and the like as nanometer level evaluation methods, but all of them require high vacuum conditions and thinning of the sample, and it is difficult to measure the sample to be observed as it is. On the other hand, with the progress of X-ray focusing technology in recent years, micrometer level X-ray beams have been obtained, and X-ray diffraction and fluorescent X-rays using such X-ray beams have been obtained. Material evaluation such as analysis has finally become possible.

  X-ray beam condensing can be broadly divided into (A) a technique using an X-ray optical element such as an X-ray mirror (see Non-Patent Document 1), and (B) asymmetric Bragg reflection of a crystal. Method (see Non-Patent Document 2), (C) Method using an X-ray Fresnel zone plate (see Non-Patent Document 3 and Non-Patent Document 4), (D) Method using a transmissive laminated zone plate (Non-Patent Document) 5), (E) There is a method using an X-ray waveguide (see Non-Patent Document 6).

  Of these, the method of using the optical element for X-rays such as the X-ray mirror of (A) and the method of using the asymmetric Bragg reflection of the crystal of (B) are almost at the technical limit at present. Condensation is difficult.

On the other hand, in the hard X-ray region where the X-ray energy is 5 keV or more, a focused beam having a beam size of 100 nanometers or less is obtained by the method (C) using the X-ray Fresnel zone plate. When the Fresnel zone plate is irradiated with an X-ray beam, a part of the X-ray beam is absorbed by the zone plate and is not transmitted, but other X-ray beams are transmitted as they are. At this time, assuming that the wavelength of the X-ray beam is λ and the focal length of the X-ray Fresnel zone plate is f, (2nλf) ^1/2 (n Is between 0, 1, 2,...) And {(2n + 1) λf} ^1/2 , or {(2n + 1) λf) ^1/2 and {(2n + 2) λf} ^{1 / If} a shielding zone made of a material that does not transmit X-rays is provided between the position ² and the transmitted X-rays interfere with each other, the X-ray beam can be condensed.

  This condensing principle is the same as that of visible light, and details thereof are described in Non-Patent Document 7, for example, and it is known that the spatial resolution of the zone plate condensing system is substantially equal to the outermost zone width. . Therefore, in the case of an X-ray Fresnel zone plate, the maximum spatial resolution is defined by the width of the narrowest shielded zone constituting the zone plate. In order to manufacture such a zone plate, lithography technology for semiconductor manufacturing including electron beam drawing is used. Although the semiconductor lithography technology itself can draw a linear pattern of 10 nanometers, when producing a ring-shaped pattern necessary as an X-ray Fresnel zone plate, drawing of a width of about 40 nanometers is currently limited. Yes, the resolution of the X-ray Fresnel zone plate itself is about 50 nanometers. Furthermore, when producing an X-ray Fresnel zone plate, since it is necessary to precisely produce a large number of ring-shaped patterns, the X-ray Fresnel zone plate itself is very expensive.

In the X-ray Fresnel zone plate, X-rays were collected by providing a shielding zone through which X-rays cannot be transmitted. Further, in order to increase the light collection efficiency, an X-ray phase shifter layer that transmits X-rays but shifts the phase of X-rays is provided instead of the shielding zone, or this phase shifter layer is formed in a multistage structure. Thus, a method for further improving the light collection efficiency has been proposed. On the other hand, in the case of the method using the transmissive laminated zone plate of (D), a structure in which a heavy element layer that transmits X-rays and a light element layer that transmits X-rays is used. In Non-Patent Document 5, the distance along the Z direction from the center of the X-ray beam is (2nλf ₁ ) ^1/2 (where n is 0, 1, 2,...) And {(2n + 1) λf ₁ ). X-rays are linearly collected by the laminated Fresnel zone plate structure disposed in either the first region between the ^half positions or the second region excluding the first region. Possibilities have been proposed in recent years. In addition, a method of condensing dots in a spot shape by combining two stacked Fresnel zone plate structures has been recently proposed.

On the other hand, in the case of the method using the X-ray waveguide of (E), the size of the X-ray beam is determined by the size of the core constituting the waveguide. Here, when the refractive index in the X-ray region of the core layer is N ₁ and the refractive index in the X-ray region of the cladding layer covering the core layer is N ₂ , (the real part of N ₁ ) <(the real number of N ₂ ) Part). When an X-ray beam is incident on the core layer of the X-ray waveguide, the X-ray beam travels through the core layer. At this time, when the thickness D of the core layer is sufficiently small, only X-rays in a specific state are transmitted. At this time, the thickness D of the core layer, the wavelength λ of the X-ray beam, and the cladding layer of the X-ray beam Is known to have the following relationship with the incident angle φ (see Non-Patent Document 8).
2Dsin (φ) = mλ (m = 0, 1, 2,...) (1)

  The condition of formula (1) indicates that there is a limit to the incident angle φ of the X-ray incident on the X-ray waveguide, and X-rays having other incident angles cannot pass through the core layer. Is shown. The angle at which total reflection occurs is selected as the incident angle φ of the X-ray beam from the core layer to the cladding layer, and the length is such that all the X-ray beam passing through the cladding layer is absorbed and does not pass through the waveguide exit. When the X-ray waveguide is used, the X-ray beam can be condensed to a size substantially the same as the size of the core layer at the waveguide exit. Since such an X-ray waveguide can be manufactured by vapor deposition, it is easy to reduce the thickness of the core layer to 10 nanometers or less, and an X-ray beam having a size of several nanometers can be manufactured. It is possible in principle.

  However, in the case of a method using an X-ray waveguide, an X-ray beam can be condensed in the thickness direction of the core, but the in-plane direction of the core perpendicular to the thickness direction and the traveling direction of the beam. X-rays cannot be collected. That is, the X-rays that can be extracted at the exit of the X-ray waveguide have the same size as the incident X-rays in the horizontal direction. It is difficult to obtain a point-shaped X-ray microbeam that is focused in a two-dimensional direction.

  As described above, it is difficult to obtain an X-ray beam having a size of 10 nanometers by a method using an X-ray Fresnel zone plate, and an X-ray having a size of several nanometers is obtained by a method using an X-ray waveguide. Although it is possible to obtain a ray beam, there is a problem that the X-ray beam is condensed in only a one-dimensional direction, an X-ray beam condensed in a two-dimensional direction cannot be obtained, and the X-ray intensity is weak. There was a point (refer nonpatent literature 9). As described above, with the progress of research on nanostructured materials, a technique for evaluating nanostructured materials with a spatial resolution of 10 nanometer level is required. However, the conventional X-ray beam focusing method has a level of 10 nanometer level. It is difficult to achieve a spatial resolution of

In order to overcome such technical difficulties, the inventor sandwiched the upper and lower sides of the core thin film layer having a refractive index of N ₁ in the X-ray region with the clad thin film layer having a refractive index of N ₂ , and the refractive index N _1. And an X-ray waveguide having a relationship of (N ₁ real part) <(N ₂ real part) between N ₂ and N ₂ , a part of the waveguide is configured by a shielding layer that does not transmit X-rays An X-ray condensing lens that can form an X-ray microbeam condensed at a nanometer level in the vertical and horizontal directions by incorporating a Fresnel zone plate has been proposed (see Patent Document 1). Hereinafter, the X-ray condenser lens proposed in Patent Document 1 is referred to as the X-ray condenser lens of Conventional Technique 1.

  FIG. 5A is a plan view showing the configuration of the X-ray condenser lens of Prior Art 1, and FIG. 5B is a cross-sectional view taken along the line I-I of the X-ray condenser lens of FIG. In FIG. 5A, it is assumed that an X-ray shielding layer and an X-ray beam under the upper ruthenium layer described later are seen through. The X-ray condenser lens includes an X-ray waveguide portion 114 for condensing the X-ray beam in the vertical direction, an X-ray zone plate portion 115 for condensing the X-ray beam in the horizontal direction, and an X-ray collector. And an optical part 116.

  5A and 5B, reference numeral 108 denotes a silicon substrate, 109 denotes a lower ruthenium layer which is a cladding layer formed on the silicon substrate 108, and 110 denotes a core formed on the lower ruthenium layer 109. A carbon layer 111, an upper ruthenium layer 111 being a cladding layer formed on the carbon layer 110, and a part 112 of an X-ray waveguide composed of the lower ruthenium layer 109, the carbon layer 110, and the upper ruthenium layer 111. 2 is an X-ray shielding layer made of a tantalum material that functions as an X-ray zone plate.

The X-ray shielding layer 112 has a distance along the direction orthogonal to the traveling direction of the X-ray beam 113 from the center of the X-ray beam 113 when the wavelength of the X-ray is λ and the focal length as the condenser lens is f _1. Is any _one of the first region between the position of Z _2n (n is 0, 1, 2,...) And the position of Z _{2n + 1} , or the second region excluding the first region. And arranged upstream from the X-ray waveguide exit 17 by a focal length f ₁ along the direction opposite to the traveling direction of the X-ray beam 113. 5A and 5B, the traveling direction of the X-ray beam 113 is the right direction in FIGS. 5A and 5B and the direction orthogonal to the traveling direction of the X-ray beam 113. It is the up-down direction of FIG.

The distances (coordinates) Z _2n and Z _{2n + 1} from the center of the X-ray beam of the X-ray shielding layer 112 are obtained by the following equations.
Z _2n = (2nλf ₁ ) ^1/2 (2)
Z _{2n + 1} = {(2n + 1) λf ₁ }} ^1/2 (3)

  Further, the inventor replaces the X-ray shielding layer 112 in the X-ray condenser lens of the prior art 1 with an X-ray phase shifter layer that transmits X-rays but shifts the phase of X-rays, thereby transmitting X-rays. The X-ray condensing lens which can make a rate 4 times was proposed (refer patent document 2). Hereinafter, the X-ray condenser lens proposed in Patent Document 2 is referred to as the X-ray condenser lens of Conventional Technique 2.

  Furthermore, the inventor can further improve the X-ray transmittance by replacing the X-ray phase shifter layer in the X-ray condenser lens of the prior art 2 with a phase shifter layer having a multi-stage structure. (See Patent Document 3). Hereinafter, the X-ray condenser lens proposed in Patent Document 3 is referred to as the X-ray condenser lens of Conventional Technique 3.

  The inventor has also provided an X-ray condensing lens on the upper clad layer of the X-ray condensing part of the X-ray condensing lens in order to effectively introduce the incident X-rays into the X-ray condensing lens. A line condensing lens was proposed (Japanese Patent Application No. 2008-185718). Hereinafter, the X-ray condensing lens proposed in Japanese Patent Application No. 2008-185718 will be referred to as the X-ray condensing lens of Prior Art 4.

JP 2008-002939 A JP 2009-047430 A JP 2009-121904 A

Yamauchi et al., “Two-dimensional Submicron Focusing of Hard X-rays by Two Elliptical Mirrors Fabricated by Plasma Chemical Vaporization Machining and Elastic Emission Machining”, Jpn.J.Appl.Phys., Vol.42, 2003, p.7129-7134 Tsusaka et al., “Formation of Parallel X-Ray Microbeam and Its Application”, Japanese Journal of Applied Physics, Vol.39, 2000, L635-L637 E. Spiller, “Soft X-ray Optics”, The international Society for Optical Engineering, p. 81-97 E.Di Fabrizio, et al., “High-efficiency multilevel zone plates for keV X-rays”, Nature, Vol. 401, 1999, p.895-898 HCKang, J.Maser, GBStephenson, C.Liu, R.Conley, ATMacrander, and S.Vogt, “Nanometer Linear Focusing of Hard X Rays by a Multilayer Laue Lens”, Phys. Rev. Lett., 96, 127401, 2006 Jun Kawai, “X-ray traveling wave”, Surface Science, Vol.22, NO.6, p.397-403, 2001 Hiroshi Kubota, “Wave Optics”, Iwanami Shoten, p.305, 1971 W. Jark et al., “High gain beam compression in new-generation thin-film X-ray waveguide”, Applied Physics Letters, vol. 78, No. 9, 2001, p.1192-1194 Sadao Aoki et al., “Basics of Synchrotron Radiation Experiment III. X-ray Microbeam and its Applications”, p.68-86, PF Roundtable 1997

  In the X-ray condensing lens of Prior Art 1, the X-ray condensing part in the X-ray waveguide structure is composed of an X-ray transmitting layer and an X-ray shielding layer. In the X-ray condenser lens of the prior art 2, in order to improve the condensing efficiency of the X-ray condenser lens of the prior art 1, an X-ray phase shifter layer is provided instead of the X-ray shielding layer. X-ray absorption was prevented from occurring. In the X-ray condensing lens of the prior art 3, in order to further increase the condensing efficiency, the efficiency is further improved by forming the phase shifter layer in a multistage structure. However, the structures of the Fresnel zone plates of the prior art 1, 2, and 3 are all structures that roughly approximate the ideal Fresnel zone plate, and for this approximation, the X-ray phase is shifted in the X-ray condensing unit, Since the condensed X-rays are blurred, there is a problem that it is difficult to reduce the resolution of the coherent condensed X-rays to several nanometers or less.

  The present invention is intended to solve this problem, and realizes a high-efficiency, high-efficiency, high-resolution X-ray microbeam at the nanometer level, which was difficult with conventional X-ray beam focusing technology. An object of the present invention is to provide an X-ray condensing lens capable of achieving the above.

The present invention provides an X-ray focusing lens for focusing the X-rays using a sandwiching X-ray waveguide the upper and lower core layers in clad layer, a part or the of the core layer which X-rays are incident formed in the front of the core layer has a X-ray phase shifter layer ing of a material X-rays pass, and said core layer upper cladding layer X-ray shielding layer formed on a part of the top of the The X-ray phase shifter layer has a wavelength of X-rays in the X-ray phase shifter layer λ, an angle formed by the incident direction of the X-ray beam and the principal surface of the cladding layer, and a width of the X-ray beam. W, where f is the focal length of the X-ray condenser lens, AX is the traveling direction of the X-ray beam in the core layer, AZ is the stacking direction of the core layer and the cladding layer out of the directions orthogonal to the traveling direction AX, The direction orthogonal to the AX and AZ is AY, and the center of the X-ray beam is along the AY direction. Distance _{Y n (DX) = a n} (DX) {nλf + n 2 λ 2/4} 1/2 (n is index of the zone in which the X-ray phase shifter layer is _{disposed, a n (DX) = 1} -DX / {2f (1 + nλ / 4f)}, DX is a distance along the AX direction from the end face on the entrance side of the X-ray phase shifter layer) , and when the length in the AX direction of the X-ray phase shifter layer is t The X-ray shielding layer is disposed in a first region between the position of Y _n (0) and the position of Y _n (t), and the X-ray shielding layer has a thickness of a clad layer above the core layer as K ₁ , When the thickness of the core layer is D, the thickness of the cladding layer under the core layer is K ₂ , and the thickness of the X-ray shielding layer is K ₃ , the position of the end face on the inlet side is the outlet of the core layer along the position of the end face of a side in the AX direction opposite (f + W / sinφ) is arranged so as to be more upstream position, K _3> W / c A Esufai, is characterized in that the distance from the position of the end face on the inlet side of the core layer to the position of the end face on the inlet side of the X-ray shielding layer is greater than or equal to zero.

Additionally, in an example of the X-ray focusing lens of the present invention, the X-ray phase shifter layer, the position of the inlet-side end surface of f only along the focal point of the X-ray focusing lens in the AX direction opposite It is arrange | positioned so that it may become an upstream position.
Further, in one configuration example of the X-ray condenser lens of the present invention, the cladding layer and the X-ray shielding layer are formed of W, Ru, Ta, Rb, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Ba, Re, Os, Ir, Pt, Au, Pb, Tl, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and the core layer is made of C. , O, Si, Be, Ca, Sc, Ti, V, Cr, Mn, Te, and a material including at least one of polymer materials, and the phase shifter layer includes W, Ru, Ta, Rb, Sr. Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Ba, Re, Os, Ir, Pt, Au, Pb, Tl, V, Cr, Mn, Fe, Co, Ni, Cu, Zn Material containing at least one, or C, Si, Be, Ca, Sc Ti,, V, Cr, Mn, Te is made of a material containing at least one of the polymeric materials.

Further, one configuration example of the X-ray condenser lens of the present invention further includes a laminated Fresnel zone plate structure disposed behind an X-ray waveguide including the X- ray phase shifter layer, and the laminated Fresnel zone The plate structure is a structure in which a heavy element layer made of a material that does not transmit X-rays and a light element layer made of a material that transmits X-rays are alternately stacked, and the heavy element layer has the stacked Fresnel zone plate structure. when the focal length was set to f _1, the distance along the AZ direction from the center of the X-ray beam (2mλf ₁₎ ^1/2 (m is 0, 1, 2, ...) and the position of {( 2m + 1) λf ₁ } ^1/2 , and is arranged in any one of the second region and the third region excluding the second region.

Moreover, in one structural example of the X-ray condenser lens of the present invention, the end face on the exit side of the laminated Fresnel zone plate structure is a traveling direction AX of the X-ray beam from the end face on the entrance side of the X-ray phase shifter layer. And the relationship of f = f ₁ + L is established between the focal length f of the X-ray waveguide and the focal length f ₁ of the laminated Fresnel zone plate structure. It is a feature.
In one configuration example of the X-ray condenser lens of the present invention, the heavy element layer of the laminated Fresnel zone plate structure includes W, Ru, Ta, Rb, Sr, Y, Zr, Nb, Mo, Pd, Ag. , Cd, In, Ba, Re, Os, Ir, Pt, Au, Pb, Tl, V, Cr, Mn, Fe, Co, Ni, Cu, Zn. The layer is made of a material containing at least one of C, O, Si, Be, Ca, Sc, Ti, V, Cr, Mn, Te, and a polymer material.

  According to the present invention, by providing the phase shifter layer in the X-ray waveguide, the X-ray beam can be condensed using the X-ray waveguide structure in the thickness direction of the core layer. In the direction orthogonal to the traveling direction of the X-ray beam, the X-ray beam can be condensed using the same condensing action as the X-ray Fresnel zone plate. As a result, in the present invention, it is possible to easily obtain a high-intensity X-ray microbeam focused to the nanometer order, such as quantum dots, nanodots, nanowires, nanoparticles, fine gates of highly integrated semiconductor materials, etc. It is possible to evaluate the structure of various nanomaterials and contribute to the development of semiconductor materials and semiconductor devices. Further, in the present invention, the X-ray waveguide structure has a AX direction as compared with a conventional X-ray condensing lens using a shielding layer or a multistage phase shifter layer having a certain thickness with respect to the X-ray beam traveling direction AX direction. Therefore, the resolution in the AY direction can be increased from several tens of nanometers to several nanometers. This makes it possible to obtain an X-ray beam that can be easily used for analysis of individual nanostructures. In the present invention, by providing an X-ray shielding layer and making the cladding layer above the core layer have a convex structure, X-rays totally reflected on the surface of the cladding layer can be shielded. As a result, a coherent nanoscale X-ray focused beam with less intensity unevenness and defocus can be obtained.

  Further, in the present invention, the phase shifter layer is usually arranged so that the position of the end surface on the entrance side is located upstream of the focal point of the X-ray condenser lens by the focal length f along the direction opposite to the AX direction. Further, it is easy to collect light with an X-ray mirror, and an X-ray beam that can be easily used for analysis can be obtained.

  Further, in the present invention, by arranging the laminated Fresnel zone plate structure behind the X-ray waveguide structure, a sufficient working distance between the X-ray condensing lens and the sample can be ensured, while at the nanometer level. It becomes possible to realize beam condensing with a diameter.

In the present invention, the end surface on the exit side of the laminated Fresnel zone plate structure is positioned at a distance L downstream from the end surface on the entrance side of the phase shifter layer along the traveling direction AX of the X-ray beam, by such relation f = f ₁ + L is established between the focal length f ₁ of the focal length f and the laminated type Fresnel zone plate structure of X-ray waveguide, X at a position away from the X-ray focusing lens It becomes easy to collect the rays, and an X-ray beam that can be easily used for analysis can be obtained.

It is the top view and sectional drawing which show the structure of the X-ray condensing lens which concerns on the 1st Embodiment of this invention. It is a top view for demonstrating the position of the X-ray phase shifter layer in the 1st Embodiment of this invention. It is the top view and sectional drawing which show the structure of the X-ray condensing lens which concerns on the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the position of the heavy element layer of the laminated | stacked Fresnel zone plate structure in the 2nd Embodiment of this invention. It is the top view and sectional drawing which show the structure of the conventional X-ray condensing lens.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a plan view showing the configuration of the X-ray condenser lens according to the first embodiment of the present invention, and FIG. 1B is II of the X-ray condenser lens of FIG. It is sectional drawing. In FIG. 1A, it is assumed that an X-ray phase shifter layer under the upper ruthenium layer described later is seen through. 1A actually does not have an X-ray shifter layer, but FIG. 1B shows an X-ray phase shifter to clarify the position of the X-ray shifter layer. Layers shall be listed for convenience.

  The X-ray condensing lens of the present embodiment incorporates a Fresnel zone plate in a part of the X-ray waveguide, and condenses the X-ray beam 7 in the vertical direction. An X-ray waveguide portion 8 for effectively introducing the X-ray into the waveguide, an X-ray waveguide portion 9 for effectively propagating X-rays, and an X-ray for condensing the X-ray beam in the horizontal direction The line zone plate unit 10 and an X-ray condensing unit 11 that can reduce the loss of X-rays traveling through the X-ray waveguide and shield the total reflection X-rays.

  In FIG. 1, 1 is a silicon substrate, 2 is a lower ruthenium layer which is a cladding layer formed on the silicon substrate 1, 3 is a carbon layer which is a core layer formed on the lower ruthenium layer 2, and 4 is carbon. An upper ruthenium layer 5, which is a cladding layer formed on the layer 3, is an X-ray zone plate formed in a part of an X-ray waveguide composed of the lower ruthenium layer 2, the carbon layer 3 and the upper ruthenium layer 4. An X-ray phase shifter layer made of a silver material functioning as 6 and an X-ray shielding layer 6 made of ruthenium.

In the example of FIGS. 1A and 1B, the center of the X-ray beam is the II line in FIG. 1A, the traveling direction of the X-ray beam is AX, and the direction orthogonal to the traveling direction AX is the same. Among these, the stacking direction of the core layer and the cladding layer of the X-ray waveguide lens structure is AZ, and the direction orthogonal to AZ and AZ is AY.
Here, when the refractive index in the X-ray region of the core layer of the X-ray waveguide structure is N ₁ , the refractive index in the X-ray region of the cladding layer is N ₂ , and the refractive index of the X-ray phase shifter layer is N _3. The refractive indexes N ₁ , N _2, and N _{3 have} a relationship of (the real part of N ₁ ) <(the real part of N ₃ ) <(the real part of N ₂ ).

Further, the width of incident X-rays is W, the film thickness of the upper ruthenium layer 4 is K ₁ , the film thickness of the carbon layer 3 is D, the film thickness of the lower ruthenium layer 2 is K ₂ , and the X-ray shielding layer 6 also serves as the cladding layer. the film thickness and K _3, the angle of incidence on the cladding layer of the X-ray beam 7 phi, the focal length of the X-ray focusing lens f, and the length of the beam traveling direction of the X-ray phase shifter layer 5 and t The X-ray shielding layer 6 is positioned upstream of the position of the end face on the entrance side from the position of the end face on the exit side of the carbon layer 3 in the direction opposite to the traveling direction AX of the X-ray beam 7 (f + W / sinφ) or more. It is arranged to become. Further, there is a relationship of K ₃ > W / cos φ, K ₁ <K ₂ , K ₁ <K ₃ , and from the position of the end face on the inlet side of the carbon layer 3 to the position of the end face on the inlet side of the X-ray shielding layer 6 There is a relationship that the distance is zero or more.

The X-ray phase shifter layer 5 of the X-ray condenser lens extends along the direction AY perpendicular to the traveling direction AX of the X-ray beam from the center of the X-ray beam when the wavelength of the X-ray is λ and the zone index is n. The distance is arranged in a region between the position of Y _n (0) and the position of Y _n (t), and the end face on the X-ray entrance side is opposite to the X-ray beam traveling direction AX from the X-ray waveguide exit 12. It is arranged at a position upstream by f along the direction.

The distance (coordinates) Y _n (DX) from the center of the X-ray beam of the X-ray phase shifter layer 5 is obtained by the following equation. DX is a distance along the beam traveling direction from the end face on the entrance side of the X-ray phase shifter layer 5.
_{Y n (DX) = a n} (DX) {nλf + n 2 λ 2/4} 1/2 ··· (4)
Further, a _n (DX) of the formula (4) is obtained by the following formula.
a _n (DX) = 1−DX / {2f (1 + nλ / 4f)} (5)

1A and 1B show the case where n = 4. When n = 4, the distance (coordinates) from the center of the X-ray beam is Y _n (DX) (n = 0, 1,..., 4 is 0 or t), and the X-ray phase shifter layer 5 is , so that the width of each zone is _{ΔY n (DX) = a n} (DX) (λf / 2Y) {1+ (Y / f) 2} 1/2, may be arranged in the region of the black in FIG. 2 . The maximum number of zone indices n can be about 400 or more.

  In the present embodiment, in order to prevent X-rays leaking from the cladding layer, the thickness of the lower ruthenium layer 2 and the X-ray shielding layer 6 is 100 nanometers, the thickness of the upper ruthenium layer 4 is 10 nanometers, X The thickness of the carbon layer 3 through which the line passes is 10 nanometers.

Further, in order to efficiently collect the X-rays by the X-ray zone plate portion 10, the X-ray phase shifter layer 5 is lengthened or transmitted until there is no X-ray transmitting through the X-ray phase shifter layer 5. It is necessary to cause the X-rays to interfere with each other by aligning the phase at the focal point (X-ray waveguide exit 12). In the present embodiment, a technique is adopted in which X-rays interfere with each other at the same phase at the focal point. For this reason, in this embodiment, when n = 400 and the outermost zone width ΔY is 1 nm, the length t of the X-ray zone plate portion 10 (X-ray phase shifter layer 5) is estimated to be 26 nanometers or less. When the focal length is 4.7 millimeters, the outermost zone plate width Y _{n = 400} (0) is 54 micrometers. Here, the wavelength λ of the incident X-ray is 0.154 nanometers.

Since the beam resolution is determined by the width of the outermost zone, the X-ray beam can be condensed to about 1 nanometer, and the condensing efficiency in this case is about 67%. Further, the approximation in this case, n [lambda / 4f is 1.38 × 10 ^-5 next equation (5), since this value is extremely smaller than 1, the formula (5) and _{a n (DX) = 1-} DX / 2f can do. At this time, as shown in FIG. 1, the a _n (2f) = 0 in DX = 2f.

  Next, a method for manufacturing the X-ray condenser lens of the present embodiment will be described. First, the lower ruthenium layer 2 is formed on the silicon substrate 1 by vapor deposition, for example. Silver is deposited on the lower ruthenium layer 2 and then processed by a method such as electron beam lithography to form the X-ray phase shifter layer 5. Subsequently, a carbon layer is formed on the lower ruthenium layer 2 by, for example, sputtering. At this time, the thickness of the carbon layer 3 is set to be equal to or less than the thickness of the X-ray phase shifter layer 5. Subsequently, the upper ruthenium layer 4 is formed on the carbon layer 3 and the X-ray phase shifter layer 5 by, for example, vapor deposition. Finally, the X-ray condensing lens 6 is completed by forming the X-ray shielding layer 6 on a part of the upper part of the upper ruthenium layer 4 by, for example, vapor deposition.

  When the X-ray beam 7 is made incident on the X-ray waveguide section 8 from the left side of FIGS. 1A and 1B with the incident angle φ to the X-ray condenser lens thus manufactured, the X-ray waveguide The X-rays that have passed through the part 8 pass through the X-ray waveguide part 9 with a small loss of X-rays, and then enter the X-ray zone plate part 10. At this time, part of the X-rays is phase-modulated by the X-ray phase shifter layer 5 disposed in each zone and reaches the X-ray condensing unit 11.

  Since the X-ray beam cannot spread in the direction perpendicular to the silicon substrate 1, the size of the X-ray beam in the vertical direction of the X-ray beam (the vertical direction in FIG. 1B) is the X-ray waveguide portions 8 and 9. As in the case of, it is about 10 nanometers.

  On the other hand, since there is nothing that restricts the mode of the X-ray beam in the horizontal plane of the waveguide, the X-rays emitted from the opening of the X-ray zone plate unit 10 are generated in the X-ray condensing unit 11 and in the one-dimensional Fresnel. The light travels through the zone plate structure and is condensed at the position of the X-ray waveguide outlet 12. The horizontal size of the X-ray beam at this time is determined by the minimum width of the X-ray phase shifter layer 5 (vertical dimension in FIG. 1A). At the X-ray waveguide exit 12, the vertical size of the X-ray beam is about 10 nanometers. In addition, since the minimum value of the width of the X-ray phase shifter layer 5 is about 1 nanometer, the horizontal size of the X-ray beam is about 1 nanometer.

  As exemplified above, in the X-ray condenser lens of the present embodiment, the X-ray beam can be focused in a point-like manner while effectively using the energy of the incident X-ray beam. Since an intense X-ray microbeam can be realized, advanced structural evaluation of nanometer level materials becomes possible.

  When the X-ray condenser lens of this embodiment is used for material evaluation, the light emitted from the X-ray condenser lens is directly irradiated to the material to be evaluated, or the light emitted from the X-ray condenser lens is further emitted. The material may be evaluated by collecting the light with a mirror and irradiating the material to be evaluated, or detecting X-rays diffracted by the material or fluorescent X-rays generated from the material.

  In addition, this invention is not limited to the above embodiment. For example, in the present embodiment, the X-ray phase shifter layer 5 is provided in the core layer of the X-ray waveguide, but may be provided outside the core layer. In this case, the X-ray phase shifter layer 5 may be provided so that the position of the end face on the X-ray entrance side is a position upstream from the X-ray waveguide outlet 12 by the focal length f.

  In this embodiment, carbon is used as the material for the core layer. However, the material for the core layer may be a material containing at least one of carbon, oxygen, silicon, beryllium, and a polymer material. Further, as the material of the core layer, a material containing at least one of boron, oxygen, aluminum, fluorine, calcium, magnesium, and titanium may be used, and polyimide, polymethyl methacrylate, fluorine resin, or chlorine resin is used. Also good.

  In this embodiment, ruthenium is used as the material of the cladding layer and the X-ray shielding layer, but any material containing at least one of tungsten, ruthenium, and tantalum may be used. Further, as a material for the cladding layer, a material containing at least one of nickel, cobalt, chromium, vanadium, titanium, germanium, molybdenum, zirconium, indium, rhenium, silver, gold, platinum, and tantalum may be used. The material of the X-ray phase shifter layer 5 may be the same as that of the clad layer, or a material different from the clad layer may be used among the materials mentioned as the clad layer material.

  In the present embodiment, silver is used as the material of the X-ray phase shifter layer 5, but tungsten, ruthenium, tantalum, rubidium, strontium, yttrium, zirconium, niobium, molybdenum, palladium, silver, cadmium, indium, Materials containing at least one of barium, rhenium, osmium, iridium, platinum, gold, lead, thallium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, or carbon, oxygen, silicon, beryllium, calcium Alternatively, a material containing at least one of scandium, titanium, vanadium, chromium, manganese, tellurium, and a polymer material may be used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 3A is a plan view showing the configuration of the X-ray condenser lens according to the second embodiment of the present invention, and FIG. 3B is II of the X-ray condenser lens of FIG. It is sectional drawing, and the same code | symbol is attached | subjected to the structure same as FIG. 1 (A) and FIG. 1 (B). In FIG. 3A, it is assumed that the X-ray beam passing through the X-ray phase shifter layer 5, the X-ray waveguide lens structure, and the laminated Fresnel zone plate structure is seen through. In addition, the X-ray shifter layer 5 does not actually exist at the position of the II line in FIG. 3A, but in FIG. 3B, X-rays are used to clarify the position of the X-ray shifter layer 5. The phase shifter layer 5 is described for convenience.

The X-ray condensing lens of the present embodiment includes an X-ray waveguide lens structure including an X-ray waveguide portion 8, an X-ray waveguide portion 9, an X-ray zone plate portion 10, and an X-ray collection rear portion 11, and 1 A laminated Fresnel zone plate structure 15 called a three-dimensional type Fresnel zone plate is formed on the same substrate.
In the example of FIGS. 3A and 3B, the traveling direction of the X-ray beam is AX, and the stacking direction of the core layer and the cladding layer of the X-ray waveguide lens structure is the direction orthogonal to the traveling direction AX. The direction orthogonal to AZ, AX and AZ is AY.

  Since the X-ray waveguide lens structure is the same as that of the first embodiment, description thereof is omitted. However, in the first embodiment, the position of the end face on the X-ray entrance side of the X-ray phase shifter layer 5 is the focal length f along the direction opposite to the traveling direction AX of the X-ray beam from the X-ray waveguide exit 12. Whereas the X-ray phase shifter layer 5 is arranged to be upstream, in the present embodiment, the position of the end face on the X-ray entrance side is upstream from the focal point 16 of the X-ray condenser lens by the focal length f. The X-ray phase shifter layer 5 is disposed so as to be positioned.

The stacked Fresnel zone plate structure 15 is a structure in which heavy element layers 13 that hardly transmit X-rays and light element layers 14 that transmit X-rays are alternately stacked. The heavy element layer 13 has a direction AZ perpendicular to the traveling direction AX of the X-ray beam from the center of the X-ray beam (II-II line in FIG. 3B) when the focal length as the condenser lens is f ₁ . Of the second region between the position of Z _2m (where m is 0, 1, 2,...) And the position of Z _{2m + 1} , the third region excluding this second region. It is arranged at any one of them, and is arranged upstream from the focal point 16 of the X-ray condenser lens by a focal length f ₁ along the direction opposite to the traveling direction AX of the X-ray beam. The distances (coordinates) Z _2m and Z _{2m + 1} from the center of the X-ray beam of the heavy element layer 13 are obtained by the following equations.
Z _2m = (2mλf ₁ ) ^1/2 (6)
Z _{2m + 1} = {(2m + 1) λf ₁ }} ^1/2 (7)

FIG. 4 shows a case where the heavy element layer 13 is provided in the second region between Z _2m (m is 0, 1, 2,...) And Z _{2m + 1} . When the heavy element layer 13 is provided in the third region except between Z _2m and Z _{2m + 1} , the heavy element layer 13 is disposed between the black background regions of FIG. The light element layer 14 may be disposed.

  The manufacturing method of the X-ray waveguide lens structure including the X-ray waveguide portions 8 and 9, the X-ray zone plate portion 10 and the X-ray condensing portion 11 is substantially the same as that of the first embodiment. In the embodiment, the mesa structure is formed on the silicon substrate 1 by etching, and the lower ruthenium layer 2 is formed only on the mesa structure using a mask. The subsequent steps are as described in the first embodiment.

Next, a manufacturing method of the laminated Fresnel zone plate structure 15 of the present embodiment will be described. It is made of tungsten so that the position at a distance L downstream from the end surface on the entrance side of the X-ray phase shifter layer 5 along the traveling direction AX of the X-ray beam becomes the end surface on the exit side of the laminated Fresnel zone plate structure 15. The heavy element layer 13 and the light element layer 14 made of tungsten silicide are alternately formed by, for example, sputtering. In the present embodiment, the heavy element layer 13 is provided in the second region between Z _2m shown in Formula (6) and Z _{2m + 1} shown in Formula (7). At this time, the X-ray beam incident from the X-ray waveguide lens structure is arranged so that the position of the center in the AZ direction (II-II line in FIG. 3B) coincides with the center of the central heavy element layer 13. . This completes the production of the X-ray condenser lens.

  When the X-ray beam 7 is incident on the X-ray condenser lens thus manufactured from the left side of FIGS. 3A and 3B, it proceeds in a waveguide mode depending on the length of the X-ray waveguide lens structure. Although the presence of X-rays other than X-rays may not be ignored, in this embodiment, the length of the X-ray waveguide lens structure and the length of the laminated Fresnel zone plate structure 15 are each 10 millimeters. Since this value is sufficiently larger than the wavelength of the X-ray, only the X-ray beam that passes through the X-ray waveguide lens structure satisfies the formula (1) and is perpendicular to the silicon substrate 1. The size of the X-ray beam in the direction (vertical direction in FIG. 3B) is about 10 nanomail.

  The principle of X-ray focusing by the X-ray waveguide lens structure including the X-ray waveguide sections 8 and 9, the X-ray zone plate section 10 and the X-ray focusing section 11 is as described in the first embodiment. is there. The difference from the first embodiment is that the horizontal condensing position is changed from the X-ray waveguide exit 12 shown in FIGS. 1A and 1B to the focal point 16. The vertical size of the X-ray beam at the exit 12 of the X-ray waveguide lens structure is about 10 nanometers. The X-ray beam emitted from the outlet 12 is emitted in the vertical direction with a divergence angle that is twice the incident angle. This X-ray beam is condensed again by the laminated Fresnel zone plate structure 15 disposed behind the X-ray waveguide lens structure.

  On the other hand, the X-rays emitted from the X-ray zone plate portion 10 of the X-ray waveguide lens structure travel through the X-ray condensing portion 11 and the laminated Fresnel zone plate structure 15 as a one-dimensional spherical wave. As a result, the X-rays traveling through the X-ray condensing unit 11 and the laminated Fresnel zone plate structure 15 are condensed in the horizontal direction (up and down direction in FIG. 3A) by the interference effect.

Therefore, if the position of the focal point 16 by the X-ray zone plate part 10 and the X-ray condensing part 11 of the X-ray waveguide lens structure and the condensing position by the laminated Fresnel zone plate structure 15 are made to coincide, A distance can be taken between the condenser lens and the focal point 16.
In the X-ray condensing lens of the first embodiment, since X-rays are condensed on the end face of the X-ray waveguide, it is difficult to adjust a minute part depending on the shape of the sample when measuring a sample having a three-dimensional structure. It is. That is, in the X-ray condenser lens of the first embodiment, if the sample is placed at a location away from the end face of the X-ray waveguide, the X-ray emitted from the waveguide is perpendicular to the traveling direction. Since the direction again becomes divergent light and irradiates the sample, the characteristics of the nanobeam condensed by the X-ray condenser lens cannot be used effectively.

  On the other hand, in the present embodiment, the working distance between the X-ray condenser lens and the sample is sufficiently ensured by arranging the laminated Fresnel zone plate structure behind the X-ray waveguide lens structure. However, it is possible to realize beam condensing with a diameter of nanometer level. Thereby, in this Embodiment, the freedom degree of the alignment at the time of sample measurement can be raised.

  In this embodiment, tungsten is used as the material of the heavy element layer 13, but the material of the heavy element layer 13 is Ru, Ta, Rb, Sr, Y, Zr, Nb, Mo, Pd, Ag, Any material containing at least one of Cd, In, Ba, Re, Os, Ir, Pt, Au, Pb, Tl, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn may be used. Further, tungsten silicide is used as the material of the light element layer 14, but the material of the light element layer 14 is C, O, Si, Be, Ca, Sc, Ti, V, Cr, Mn, Te, a polymer material. A material including at least one of them may be used, and polyimide, polymethyl methacrylate, a fluorine resin, or a chlorine resin may be used.

  The present invention can be applied to an X-ray condensing device.

  DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Lower ruthenium layer, 3 ... Carbon layer, 4 ... Upper ruthenium layer, 5 ... X-ray phase shifter layer, 6 ... X-ray shielding layer, 7 ... X-ray beam, 8, 9 ... X-ray conduction Waveguide part, 10 ... X-ray zone plate part, 11 ... X-ray condensing part, 12 ... X-ray waveguide exit, 13 ... Heavy element layer, 14 ... Light element layer, 15 ... Laminated Fresnel zone plate structure, 16 ... The focal point of the X-ray condenser lens.

Claims (6)

An X-ray focusing lens for focusing the X-rays using a sandwiching X-ray waveguide the upper and lower core layers in clad layer,
X-rays are formed in front of a part or the core layer of the core layer to the incident, the X-ray phase shifter layer ing of a material X-rays pass,
An X- ray shielding layer formed on a part of the upper part of the cladding layer above the core layer,
The X-ray phase shifter layer has a wavelength of X-rays in the X-ray phase shifter layer λ, an angle formed by the incident direction of the X-ray beam and the principal surface of the cladding layer, and a width of the X-ray beam W The focal length of the X-ray condenser lens is f, the traveling direction of the X-ray beam in the core layer is AX, and the stacking direction of the core layer and the cladding layer out of the directions orthogonal to the traveling direction AX is AZ, AY and a direction perpendicular to AX and AZ, the X-ray beam center distance Y _n (DX) along the AY direction from _{= a n (DX) {nλf} + n 2 λ 2/4} 1/2 (n is index of the zone in which the X-ray phase shifter layer is _{disposed, a n (DX) = 1} -DX / {2f (1 + nλ / 4f)}, DX in the AX direction from the end face on the inlet side of the X-ray phase shifter layer along distance), the AX direction of the length of the X-ray phase shifter layer and t When disposed in the first region between the position of Y _n (0) position and Y _n (t),
In the X-ray shielding layer, the thickness of the cladding layer above the core layer is K ₁ , the thickness of the core layer is D, the thickness of the cladding layer below the core layer is K ₂ , and the X-ray shielding layer is When the film thickness of the layer is K ₃ , the position of the end face on the inlet side is an upstream position of (f + W / sinφ) or more along the direction opposite to the AX direction from the position of the end face on the outlet side of the core layer. K ₃ > W / cos φ, and the distance from the position of the end face on the entrance side of the core layer to the position of the end face on the entrance side of the X-ray shielding layer is zero or more X-ray condenser lens. The X-ray condenser lens according to claim 1,
The X-ray phase shifter layer is disposed such that the position of the end face on the entrance side is located upstream from the focal point of the X-ray condenser lens by f along the direction opposite to the AX direction. Line condensing lens. In the X-ray condensing lens according to claim 1 or 2,
The cladding layer and the X-ray shielding layer are W, Ru, Ta, Rb, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Ba, Re, Os, Ir, Pt, Au, Pb, It consists of a material containing at least one of Tl, V, Cr, Mn, Fe, Co, Ni, Cu, Zn,
The core layer is made of a material including at least one of C, O, Si, Be, Ca, Sc, Ti, V, Cr, Mn, Te, and a polymer material,
The X-ray phase shifter layer includes W, Ru, Ta, Rb, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Ba, Re, Os, Ir, Pt, Au, Pb, Tl, Material containing at least one of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, or C, Si, Be, Ca, Sc, Ti, V, Cr, Mn, Te, polymer materials An X-ray condensing lens comprising a material containing at least one. The X-ray condenser lens according to claim 1,
Furthermore, a laminated Fresnel zone plate structure disposed behind the X-ray waveguide including the X-ray phase shifter layer,
The laminated Fresnel zone plate structure is a structure in which a heavy element layer made of a material that does not transmit X-rays and a light element layer made of a material that transmits X-rays are alternately stacked. When the focal length of the type Fresnel zone plate structure is f ₁ , the distance along the AZ direction from the center of the X-ray beam is (2mλf ₁ ) ^1/2 (m is 0, 1, 2,...) And the second region between the position of {(2m + 1) λf ₁ } ^1/2 and the third region excluding the second region, X Line condensing lens. The X-ray condenser lens according to claim 4,
An end face on the exit side of the laminated Fresnel zone plate structure is located at a distance L downstream from the end face on the entrance side of the X-ray phase shifter layer along the traveling direction AX of the X-ray beam. An X-ray condensing lens, wherein a relationship of f = f ₁ + L is established between a focal length f of the waveguide and a focal length f ₁ of the laminated Fresnel zone plate structure. The X-ray condenser lens according to claim 4 or 5,
The layered Fresnel zone plate structure heavy element layers are W, Ru, Ta, Rb, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Ba, Re, Os, Ir, Pt, Au. , Pb, Tl, V, Cr, Mn, Fe, Co, Ni, Cu, and a material containing at least one of Zn,
The light element layer is made of a material including at least one of C, O, Si, Be, Ca, Sc, Ti, V, Cr, Mn, Te, and a polymer material. lens.

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