JP2010256305A - X-ray spatial modulator and x-ray exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray spatial modulator which achieves minute strength modulation in a two-dimensional space of an X-ray beam by electric manipulation. <P>SOLUTION: The X-ray spatial modulator 1 includes an X-ray modulation means 10 where spin injection magnetization reversal elements (hereinafter, the "ELEMENTS") 5 whose magnetization directions are reversed by spin injection are arranged two-dimensionally, an element selection means 11 for selecting the ELEMENTS 5 reversing their magnetization direction among the two-dimensionally arranged ELEMENTS 5 and a magnetization reversal current injection means 12 for reversing the magnetization direction of the ELEMENTS 5 by injecting a magnetization reversal current for conducting magnetization reversal into the ELEMENTS 5 selected by the element selection means 11. The X-ray spatial modulator 1 modulates the strength distribution in a two-dimensional space of a monochrome circularly-polarized X-ray beam B2 incident into the ELEMENTS 5 and permeating the ELEMENTS 5 through the variation of the absorption ratio of the ELEMENTS 5 to the monochrome circularly-polarized X-ray beam B2 by controlling the magnetization direction of each of the ELEMENTS 5 with the element selection means 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an X-ray spatial modulation apparatus and an X-ray exposure apparatus using a spin injection type magnetization reversal element.

Conventional X-ray lithography is performed using an X-ray exposure mask made of a material that absorbs a large amount of X-rays. Elemental technologies of this X-ray lithography include an X-ray mirror, an X-ray exposure mask, a resist material, and the like, and the resolution is proportional to (λ · g) ^1/2 . Here, λ represents the wavelength of the X-ray, and g represents the gap interval between the X-ray exposure mask and the wafer.

  Shortening the wavelength of X-rays is effective for improving the resolution, but the short-wavelength X-rays increase the diffusion distance of secondary electrons due to collisions with the atoms constituting the resist and the substrate, so the image is unclear. There is a harmful effect. For this reason, conventionally, X-rays having a wavelength of 0.7 to 0.8 nm have been used. In the exposure system, the X-ray mirror is coated with SiC or Pt so that the X-ray intensity at this wavelength is maximized. The substrate of the X-ray exposure mask also uses SiC.

  To further improve the resolution, Ru or Rh is used as the mirror coating material, and the mask membrane material is changed to diamond as a resist material that does not contain Si atoms, so that X-rays with shorter wavelengths (0.7 nm or less) can be used. Development is underway to use. Moreover, W-Ti (0.2-0.7 micrometer), Ta, etc. are used as an X-ray absorber. Furthermore, recently, the limit resolution has reached about 35 nm by adding an element sensitive to short wavelength X-rays to the resist.

  The same-size X-ray lithography technology has a large depth of focus and excellent resolution, but it is difficult to produce a high-aspect ratio X-ray exposure mask for the same magnification, and synchrotron radiation, plasma X-ray generators, etc. The cost of the X-ray source can be cited as a problem.

  On the other hand, X-ray lithography technology called LIGA (LIthographie, Galvanoformung und Abformung: German) consists of processes such as X-ray exposure, electroforming, molding, etc., and features high aspect ratio and side-side nano-precision processing. . When synchrotron radiation is used as the X-ray source, the scattering inside the resist is small, and the directivity and straightness are excellent, so that the smoothness of the side surface with high aspect ratio and nano-accuracy can be obtained.

The mold described above is formed as a metal mold by electroforming a polymer mold formed by processing a resist and removing the polymer mold. A polymer molded body can be produced by filling the metal mold with a polymer by nanoimprinting, injection molding or the like and releasing the mold from the metal mold.
Furthermore, this polymer molded body can also be used as a mold. It is also possible to directly fill a polymer mold using a resist with metal or ceramics to obtain a part.

  In general, X-rays having a wavelength of 0.7 to 0.8 nm are said to be optimal for LIGA, but recently, by developing a resist that can minimize the influence of secondary electrons, a wide wavelength region ( It has been proposed to effectively use the energy field. For example, (1) the region of 500 eV to 2 keV is a high-precision microfabrication for a resist with a film thickness of 5 μm or less, and (2) the region of 2 keV to 5 keV is a micromachining with a nanometer order accuracy for a resist with a film thickness of 50 μm or less, (3) The region of 5 keV to 15 keV is a fine processing of μm order accuracy for a resist having a film thickness of 1 mm or less, and (4) the region of 15 keV or more is a processing for resist of a film thickness of cm order, etc. A region suitable for processing is proposed by (energy).

The thicker the X-ray absorber, the higher the X-ray shielding effect, but there is a problem that the aspect ratio of the X-ray exposure mask pattern increases. So far, W, Ta, WTi, WRe, Ta ₄ B, etc. have been proposed and produced as X-ray absorbers.

In addition, LIGA has an advantage of performing processing with a high degree of freedom of a three-dimensional shape that cannot be performed by normal X-ray lithography as described above, by performing tilt exposure, movement of an X-ray exposure mask, or the like.
For example, Patent Document 1 discloses a method (paragraph 0035 to paragraph) in which an X-ray exposure mask is moved with respect to a material, and an intensity distribution (cumulative exposure dose distribution) applied to the material is changed to control a processing depth. 0058, FIG. 5, FIG. 6, FIG. 8 to FIG. 10), a method using an X-ray exposure mask that makes X-ray transmission variable for each minute region (see paragraphs 0059 to 0065 and FIGS. 11 to 15), etc. Is described.

Japanese Patent No. 3380878

In conventional X-ray lithography, it is necessary to manufacture an X-ray exposure mask for each exposure pattern, which is expensive when processing a variety of exposure patterns that require a large number of exposure patterns. Alignment becomes complicated.
Even in the method of moving the X-ray exposure mask described in Patent Document 1, in order to form various shapes, X-ray exposure masks having a plurality of exposure patterns are required.
In addition, the resolution (accuracy) of manufacturing an X-ray exposure mask is determined by the deposition and etching technique of the X-ray absorber, electron beam lithography, etc. As described above, the current processing accuracy of the entire X-ray lithography is about 35 nm. It is said that there is. In the LIGA process, since the movement of the mask is necessary in the three-dimensional processing, when various shapes having different shapes are formed simultaneously on the substrate to be processed, individual X corresponding to each shape is formed. The movement of the line exposure mask is required, the number of steps in the entire processing process is increased, and the processing accuracy may be lowered depending on the alignment accuracy of the X-ray exposure mask.

  Further, when the method described in Patent Document 1 for changing the transparency for each minute region is used, it is not necessary to move the X-ray exposure mask. However, the amount of X-ray transmission using metal deposition and dissolution is not necessary. In the method (see paragraphs 0059 to 0063, FIG. 11 and FIG. 12) for controlling the transmission amount, it takes time to control the transmission amount, so that the response is slow and the processing accuracy is limited. In the method of arranging micro shutters in an array and turning on / off X-ray exposure for each micro area (see paragraphs 0064 to 0065 and FIGS. 13 to 15), the mechanically driven micro shutter has a structure. It is complicated, and there is a limit to miniaturization in manufacturing the micro shutter. Therefore, the processing accuracy using such an X-ray exposure mask is limited.

  An object of the present invention is to provide an X-ray spatial modulation apparatus capable of fine intensity modulation in a two-dimensional space of an X-ray beam by electrical operation, and further to provide an X-ray exposure apparatus using the X-ray spatial modulation apparatus. Is to provide.

  Therefore, in order to solve the above-described problem, the X-ray spatial modulation device according to claim 1 receives a monochromatic circularly polarized X-ray beam that is a monochromatic circularly polarized X-ray beam and enters the monochromatic circularly polarized X-ray. An X-ray spatial modulation device that modulates the intensity distribution of a line beam in a two-dimensional space, comprising: an X-ray modulation means; an element selection means; and a magnetization reversal current injection means; By controlling the magnetization direction of the spin-injection type magnetization reversal element through current injection means to change the absorptance of the spin-injection type magnetization reversal element with respect to the monochromatic circularly polarized X-ray beam, The intensity of the monochromatic circularly polarized X-ray beam incident on the reversal element and transmitted through the spin injection type magnetization reversal element is modulated.

According to such a configuration, the X-ray spatial modulation device includes the X-ray modulation means in which the spin injection type magnetization reversal elements whose magnetization directions are reversed by spin injection are arranged two-dimensionally. Are selected from the spin-injection type magnetization reversal elements arranged in the same manner. The X-ray spatial modulation device uses a magnetization reversal current injection unit to inject a magnetization reversal current, which is a current for reversing the magnetization direction, into the spin injection type magnetization reversal element selected by the element selection unit. Spins are injected into the magnetization reversal element, and its magnetization direction is reversed.
Here, since the absorptance with respect to the monochromatic circularly polarized X-ray beam varies depending on the magnetization direction of the spin injection type magnetization switching element, the intensity of the monochromatic circularly polarized X-ray beam transmitted through the spin injection type magnetization switching element is: Modulation is performed according to the magnetization direction of the spin injection type magnetization reversal element.
Therefore, in the X-ray spatial modulation device, the element selection means controls the magnetization direction of each spin injection type magnetization switching element via the magnetization switching current injection means, thereby making the spin injection type magnetization switching element two-dimensional. The intensity distribution in a two-dimensional space of a monochromatic circularly polarized X-ray beam that passes through the arranged X-ray modulation means is modulated.

  The X-ray spatial modulation device according to claim 2, in which a monochromatic circularly polarized X-ray beam that is a monochromatic circularly polarized X-ray beam is incident, and an intensity distribution of the incident monochromatic circularly polarized X-ray beam in a two-dimensional space is calculated. An X-ray spatial modulation device for modulating, comprising: an X-ray modulation means, an element selection means, and a magnetization reversal current injection means, wherein the element selection means is connected to the spin injection type via the magnetization reversal current injection means By controlling the magnetization direction of the magnetization switching element to change the reflectance of the spin injection type magnetization switching element with respect to the monochromatic circularly polarized X-ray beam, the spin injection type magnetization switching element is incident on the spin injection type magnetization switching element. The intensity of the monochromatic circularly polarized X-ray beam that reflects the magnetization switching element is modulated.

According to such a configuration, the X-ray spatial modulation device includes the X-ray modulation means in which the spin injection type magnetization reversal elements whose magnetization directions are reversed by spin injection are arranged two-dimensionally. Are selected from the spin-injection type magnetization reversal elements arranged in the same manner. The X-ray spatial modulation device uses a magnetization reversal current injection unit to inject a magnetization reversal current, which is a current for reversing the magnetization direction, into the spin injection type magnetization reversal element selected by the element selection unit. Spins are injected into the magnetization reversal element, and its magnetization direction is reversed.
Here, since the reflectivity of the spin-injection type magnetization reversal element changes with respect to the monochromatic circularly-polarized X-ray beam according to the magnetization direction, the intensity of the monochromatic circularly-polarized X-ray beam that reflects the spin-injection type magnetization reversal element is Modulation is performed according to the magnetization direction of the spin injection type magnetization reversal element.
Therefore, in the X-ray spatial modulation device, the element selection means controls the magnetization direction of each spin injection type magnetization switching element via the magnetization switching current injection means, thereby making the spin injection type magnetization switching element two-dimensional. The intensity distribution in a two-dimensional space of a monochromatic circularly polarized X-ray beam reflected from the arranged X-ray modulation means is modulated.

  The X-ray spatial modulation device according to claim 3 is the X-ray spatial modulation device according to claim 1 or 2, wherein the X-ray modulation means is disposed in a stripe pattern on the substrate and the substrate. A plurality of lower electrodes and a plurality of upper electrodes arranged in a stripe shape in a direction orthogonal to the lower electrodes are provided.

  According to such a configuration, both ends of the spin injection type magnetization reversal element are electrically connected to the lower electrode and the upper electrode in the region where the lower electrode and the upper electrode intersect in plan view of the X-ray modulation means. Is done. The X-ray spatial modulation device uses a magnetization reversal current injection means to apply a voltage between the lower electrode and the upper electrode, so that the spin injection type magnetization disposed between the lower electrode and the upper electrode to which the voltage is applied. A magnetization reversal current is injected into the reversal element.

  The X-ray spatial modulation device according to claim 4 is the X-ray spatial modulation device according to claim 3, wherein the spin-injection magnetization reversal element is arranged between the lower electrode and the upper electrode in order from the lower electrode side. It has a stacked columnar structure in which a magnetization direction fixed layer, an intermediate layer made of a nonmagnetic material, and a magnetization direction variable layer made of a ferromagnetic material whose magnetization direction is reversed by injection of a magnetization reversal current, are stacked, and spin injection type magnetization The inversion element is configured to be erected on the substrate via an insulating layer.

  According to such a configuration, the spin-injection type magnetization reversal elements are arranged upright on the substrate, and adjacent spin-injection type magnetization reversal elements are electrically and magnetically insulated from each other by the insulating layer. The For this reason, each spin-injection type magnetization reversal element has a magnetization reversal current injection means that a voltage is applied between the lower electrode and the upper electrode to inject a magnetization reversal current, thereby adjacent spin-injection type magnetization reversal. The magnetization direction of the magnetization direction variable layer is reversed independently of the element, and the absorptance or reflectance of the magnetization direction variable layer with respect to the monochromatic circularly polarized X-ray beam changes.

  The X-ray spatial modulation device according to claim 5 is the X-ray spatial modulation device according to claim 4, wherein the monochromatic circularly polarized X-ray has a wavelength corresponding to an inner-shell electron binding energy of an element constituting the magnetization direction variable layer. We decided to modulate the intensity of the beam.

According to such a configuration, the X-ray spatial modulation device transmits or reflects a monochromatic circularly polarized X-ray beam having a wavelength corresponding to the inner-shell electron binding energy of an element constituting the magnetization direction variable layer through the magnetization direction variable layer. To modulate its intensity.
Note that the wavelength corresponding to the inner-shell electron binding energy refers to the magnetization when the inner-shell absorption of the element constituting the magnetization direction variable layer is measured using a monochromatic circularly polarized X-ray beam generated by an X-ray source. The entire circularly polarized X-ray of energy generated under the setting conditions of the X-ray source in which the difference in absorptance (MCD) appears so as to be reversed is shown. The maximum modulation degree can be obtained under the setting conditions of the X-ray source that maximizes the MCD.

  The X-ray spatial modulation device according to claim 6 is the X-ray spatial modulation device according to any one of claims 1 to 5, wherein the element selection means is a spin injection type for reversing the magnetization direction. The magnetization reversal element is selected in a time-sharing manner.

  According to such a configuration, the X-ray spatial modulation device transmits or transmits the spin-injection type magnetization reversal element by time-division selection of the spin-injection type magnetization reversal element for reversing the magnetization direction by the element selection means. Controls the cumulative amount of reflected monochromatic circularly polarized X-ray beam.

  An X-ray exposure apparatus according to a seventh aspect includes an X-ray source and the X-ray spatial modulation apparatus according to any one of the first to sixth aspects.

  According to such a configuration, the X-ray exposure apparatus generates a monochromatic circularly polarized X-ray beam by the X-ray source and enters the X-ray spatial modulation apparatus. The X-ray exposure device modulates the intensity distribution of the transmitted X-ray or reflected X-ray in a two-dimensional space by transmitting or reflecting the monochromatic circularly polarized X-ray beam incident from the X-ray source by the X-ray spatial modulation device. To do. The X-ray exposure apparatus uses X-rays modulated by the X-ray spatial modulation apparatus as exposure X-rays.

  According to the first or second aspect of the present invention, the X-ray spatial modulation device is an X-ray beam that is transmitted or reflected by the spin-injection magnetization switching element by controlling the magnetization direction of each spin-injection magnetization switching element. Therefore, the intensity distribution in the two-dimensional space can be modulated with the spin injection type magnetization reversal element as a unit of resolution at a fast response speed. Further, since the spin injection type magnetization reversal element has no moving parts and can be formed with high density, the intensity distribution of the X-ray beam can be finely modulated in a two-dimensional space.

According to the third aspect of the present invention, the X-ray spatial modulation device applies a voltage selectively to a spin-injection magnetization reversal element that reverses the magnetization direction by stripe-shaped electrodes orthogonal to each other, thereby reversing the magnetization. The intensity distribution of the X-ray beam in the two-dimensional space can be easily modulated by electrical operation.
According to a fourth aspect of the present invention, an X-ray spatial modulation device has a stacked columnar structure including a magnetization direction variable layer as a spin-injection type magnetization reversal element on a substrate of an X-ray modulation means via an insulating layer. Therefore, the spin-injection type magnetization reversal elements, which are units of resolution of intensity distribution in the two-dimensional space of modulated X-rays, can be arranged at high density. For this reason, the X-ray spatial modulation device can finely control the intensity distribution of the X-ray beam in the two-dimensional space.

  According to the invention described in claim 5, the X-ray spatial modulation device is a monochromatic circularly polarized X-ray having a wavelength corresponding to the inner-shell electron binding energy of an element constituting the magnetization direction inversion layer in which the absorptance or reflectance changes. Since the intensity of the beam is modulated, the difference in absorptance or reflectance due to the reversal of the magnetization direction of the magnetization direction variable layer can be increased, and a high degree of modulation can be obtained.

According to the sixth aspect of the present invention, the X-ray spatial modulation device accumulates X-ray beams that are transmitted or reflected through the spin injection type magnetization reversal element by selecting the magnetization direction of the spin injection type magnetization reversal element in a time-sharing manner. In order to control the amount of light, it is possible to substantially perform multi-step intensity modulation using a spin injection type magnetization reversal element capable of two-step intensity modulation by reversing the magnetization direction.
According to the seventh aspect of the present invention, the X-ray exposure apparatus can finely control exposure in a two-dimensional space at high response speed by electrical operation. As a result, when the X-ray exposure apparatus of the present invention is used for lithography, fine three-dimensional processing with a high degree of freedom can be easily performed without moving the X-ray exposure mask.

It is a schematic diagram which shows the structure of the X-ray spatial modulation apparatus of 1st Embodiment which concerns on this invention. It is typical sectional drawing which shows the structure of the X-ray modulation means in the X-ray spatial modulation apparatus of 1st Embodiment which concerns on this invention. It is a schematic plan view of the X-ray modulation means in the X-ray spatial modulation device of the first embodiment according to the present invention. It is a graph which shows the X-ray transmittance of the magnetic material in the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process of the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process following FIG. 5 of the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process following FIG. 6 of the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process following FIG. 7 of the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process following FIG. 8 of the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process following FIG. 9 of the X-ray spatial modulation apparatus which concerns on this invention. It is typical sectional drawing which shows the manufacturing process following FIG. 10 of the X-ray spatial modulation apparatus which concerns on this invention. FIG. 6 is a schematic plan view of the manufacturing process shown in FIG. 5 of the X-ray spatial modulation device according to the present invention. FIG. 12 is a schematic plan view of the manufacturing process shown in FIG. 11 of the X-ray spatial modulation device according to the present invention. It is a schematic diagram which shows the structure of the X-ray exposure apparatus using the X-ray spatial modulation apparatus of 1st Embodiment which concerns on this invention. It is a schematic diagram which shows the structure of the X-ray spatial modulation apparatus of 2nd Embodiment which concerns on this invention. It is typical sectional drawing which shows the structure of the X-ray modulation means in the X-ray spatial modulation apparatus of 2nd Embodiment which concerns on this invention. It is a graph which shows the X-ray reflectivity of the magnetic material in the X-ray spatial modulation apparatus of 2nd Embodiment which concerns on this invention.

Embodiments of the present invention will be described below with reference to the drawings as appropriate.
<Configuration>
First, the configuration of the X-ray spatial modulation device 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

As shown in FIG. 1, the X-ray spatial modulation device 1 includes an X-ray modulation unit 10, an element selection unit 11, and a magnetization reversal current injection unit 12. The X-ray spatial modulation device 1 modulates the X-ray intensity distribution in a two-dimensional space by transmitting the monochromatic circularly polarized X-ray beam B2 incident from the X-ray source 20 through the X-ray modulation means 10 and modulates the X-ray modulated X-ray beam B2. It is an apparatus that emits a modulated X-ray beam B3 that is a line beam.
The X-ray modulation means 10 includes a substrate 2, a lower electrode 4, a spin injection type magnetization reversal element 5, and an upper electrode 6.

  In the present invention, the intensity of incident X-rays is modulated using the spin injection type magnetization reversal element 5. As an apparatus using spatial modulation by a spin injection type magnetization reversal element, for example, there are an imaging apparatus described in Japanese Patent Application Laid-Open No. 2008-60906 and an optical modulator described in Japanese Patent Application Laid-Open No. 2008-83686. These devices utilize the principle of the Faraday rotation effect or the Kerr rotation effect. That is, the rotation angle of the polarization axis of linearly polarized visible light that is transmitted or reflected through the spin-injection type magnetization reversal element is determined using the difference in optical rotation with respect to the linearly polarized light that changes according to the magnetization direction of the spin-injection type magnetization reversal element. Modulate. Further, the intensity of visible light is modulated using a polarizing element that transmits when the polarization axis is at a predetermined rotation angle.

In contrast, the X-ray spatial modulation device 1 according to the present invention utilizes the principle of magnetic circular dichroism. That is, a circle that transmits (or reflects) the spin-injection type magnetization reversal element 5 using the difference in absorption rate (or reflectance) with respect to circularly polarized X-rays that changes according to the magnetization direction of the spin-injection type magnetization reversal element 5. It modulates the intensity of polarized X-rays.
The detailed configuration of each part of the X-ray spatial modulation device 1 will be described later.

The X-ray source 20 includes a synchrotron radiation light source 21, a monochromator 22, a wavelength selection unit 23, a phase shifter 24, and a polarity selection unit 25.
The X-ray source 20 generates a monochromatic circularly polarized X-ray beam B2 from the white linearly polarized X-ray beam B0 emitted by the synchrotron radiation source 21, and generates the generated monochromatic circularly polarized X-ray beam B2 as an X-ray spatial modulation device 1. X-ray light source incident on the X-ray.

  The synchrotron radiation light source 21 is an X-ray light source that generates a white linearly polarized X-ray beam B0 by synchrotron radiation. The synchrotron radiation light source 21 causes the generated white linearly polarized X-ray beam B0 to enter the monochromator 22.

The monochromator 22 receives the white linearly polarized X-ray beam B0 from the synchrotron radiation source 21 and splits the monochromatic X-ray having the wavelength (energy) selected by the wavelength selection unit 23 to generate the monochromatic linearly polarized X-ray beam B1. Monochrome X-ray generation means.
As the monochromator 22, for example, a double crystal monochromator which is a diffraction type spectroscopic means can be used. The monochromator 22 adjusts the incident angle of the white linearly polarized X-ray beam B0 that is the incident light to the monochromator 22 and the emission angle of the monochromatic linearly polarized X-ray beam B1 that is the emitted light by the wavelength selection unit 23. The monochromatic linearly polarized X-ray beam B1 having the selected wavelength is incident on the phase shifter 24.

The wavelength selection unit 23 adjusts the incident angle and the emission angle of the white linearly polarized X-ray beam B0 to the monochromator 22 so that the X-ray having the selected desired wavelength is incident on the phase shifter 24. 22 angle control means.
The wavelength of the X-ray selected at this time is preferably a wavelength corresponding to the inner-shell electron binding energy of an element constituting the spin-free ferromagnetic layer 53 described later. Thereby, since the difference in the X-ray absorption rate due to the reversal of the magnetization direction of the spin-free ferromagnetic layer 53 can be increased, the X-ray spatial modulation device 1 can obtain a greater degree of modulation.
Actually, in the monochromator 22 and the phase shifter 24, it is difficult to obtain a complete monochromatic circularly polarized X-ray beam due to the quality of each crystal, the accuracy of angle control, the optical axis accuracy, and the like. That is, the monochromatic X-ray includes X-rays having various wavelengths with energy close to the X-ray having a predetermined energy (ΔE / E = ^{−10 −4} , E: X-ray energy). Therefore, the wavelength corresponding to the inner-shell electron binding energy means that when measuring the inner-shell absorption of the element in the spin-free ferromagnetic layer 53 using the monochromatic circularly polarized X-ray beam B2 generated by the X-ray source 20. The entire circularly polarized X-rays of energy generated under the setting conditions of the monochromator 22, the wavelength selection unit 23, the phase shifter 24, and the polarity selection unit 25 in which the absorption ratio difference (MCD) appears when the magnetization is reversed are shown. The maximum degree of modulation can be obtained by setting the monochromator 22, the wavelength selector 23, the phase shifter 24, and the polarity selector 25 that maximizes the MCD.

The phase shifter 24 is a circularly polarized light generating unit that receives the monochromatic linearly polarized X-ray beam B1 from the monochromator 22 and generates circularly polarized light of either positive or negative polarity selected by the polarity selecting unit 25.
In the phase shifter 24, the incident angle of the monochromatic linearly polarized X-ray beam B1 is adjusted by the polarity selecting unit 25, and the phase of the monochromatic linearly polarized X-ray beam B1 is changed according to the incident angle. At this time, whether the polarity of the circularly polarized light generated is positive or negative (counterclockwise or clockwise) is determined depending on whether the phase of the monochromatic linearly polarized X-ray beam B1 is delayed by 90 ° or advanced by 90 °.
For example, a diffractive X-ray phase shifter can be used as the phase shifter 24, and circularly polarized light having a desired polarity can be selected by adjusting the diffraction angle.
The phase shifter 24 causes the generated monochromatic circularly polarized X-ray beam B2 to enter the X-ray modulation means 10 of the X-ray spatial modulation device 1.

  The polarity selection means 25 mechanically rotates the phase shifter 24 and adjusts the incident angle of the monochromatic linearly polarized X-ray beam B1 to the phase shifter 24, whereby the circularly polarized light generated by the phase shifter 24 is adjusted. It is an angle control means of the phase shifter 24 for selecting the polarity.

  As shown in FIG. 2, the X-ray modulation means 10 of the X-ray spatial modulation device 1 includes a plurality of spin-injection magnetization reversal elements (hereinafter abbreviated as “elements”) 5 on a substrate 2. 5 are arranged in an array in an electrically and magnetically insulated state by an insulating layer 3 interposed between them.

  A lower electrode 4 is disposed below each element 5 and an upper electrode 6 is disposed above the element 5. As shown in FIG. 3, the lower electrode 4 and the upper electrode 6 are disposed so as to be orthogonal to each other along the Y axis and the X axis in plan view.

  In this X-ray modulation means 10, the element 5 has a quadrangular prism shape with the bottom surface and the top surface of the quadrangular regions of each electrode where the lower electrode 4 and the upper electrode 6 overlap in plan view, as shown in FIG. ing. The elements 5 are arranged in a two-dimensional array at each intersection where the lower electrode 4 and the upper electrode 6 overlap in plan view.

  The substrate 2 is made of an insulating material, and a plurality of lower electrodes 4 are provided on the upper surface of the substrate 2. In addition, the substrate 2 is preferably made of a material having a low absorptance with respect to the X-rays to be used.

The element 5 has a columnar laminated structure in which a spin-fixed ferromagnetic layer 51, a nonmagnetic intermediate layer 52, and a spin-free ferromagnetic layer 53 are laminated in this order from the lower electrode 4 side toward the upper electrode 6.
The elements 5 are electrically and magnetically insulated by the insulating layer 3. Thereby, the magnetization direction of the spin-free ferromagnetic layer 53 in each element 5 can be reversed independently.

  The spin fixed ferromagnetic layer (magnetization direction fixed layer) 51 is a layer made of a ferromagnetic material and having a fixed magnetization direction. The magnetization direction of the spin-fixed ferromagnetic layer 51 shown in FIG. 2 is upward in the direction perpendicular to the upper surface of the X-ray modulation means 10 (the length direction of the columnar element 5). Note that the magnetization direction may be fixed downward.

As the ferromagnetic material, it is preferable to use a material having a high spin polarization such as a metal half metal. Examples thereof include materials having a large spin polarization such as Co ₂ MnAl, Co ₂ MnSi, Co ₂ Cr _0.6 Fe _0.4 Al, CoFe, CoFeB, TbFeCo, and MnSb. Examples of the oxide half metal include La _0.7 Sr _0.3 MnO ₃ , Sr ₂ Fe (W _0.4 Mo _0.6 ) O ₆ , Sr ₂ FeReO ₆ , CrO ₂ , Fe ₃ O _{4 and the} like. Is mentioned. Among these, the ferromagnetic material preferably has a high spin polarization. Further, the spin-fixed ferromagnetic layer 51 may have a two- to three-layer structure in combination with layers having different compositions using these materials and spin-fixed layers such as IrMn. The film thickness of the spin-fixed ferromagnetic layer 51 is about several nm to several tens of nm. The spin fixed ferromagnetic layer 51 is formed on the lower electrode 4 by a molecular beam epitaxy (MBE) method, a sputtering method, or the like.

  The nonmagnetic intermediate layer (intermediate layer) 52 can be formed of a nonmagnetic material such as Cu, for example. The film thickness of the nonmagnetic intermediate layer 52 is preferably set to a thickness (2 to 3 nm) at which polarized spin electrons can tunnel. The nonmagnetic intermediate layer 52 can be formed on the spin-fixed ferromagnetic layer 51 by MBE, sputtering, or the like.

  In the spin-free ferromagnetic layer (magnetization direction variable layer) 53, the magnetization direction is inverted by injection of polarized spin electrons (spin injection), and absorption of the incident monochromatic circularly polarized X-ray beam B2 is caused by the difference in the magnetization direction. It is a layer that gives a difference in rate. The magnetization direction of the spin-free ferromagnetic layer 53 is preferably perpendicular to the upper surface of the X-ray modulation means 10 (the length direction of the columnar element 5), as shown in FIG. This makes it possible to increase the thickness of the spin-free ferromagnetic layer 53 in the magnetization direction while arranging the elements 5 at a high density.

The initial state of the magnetization direction of the spin-free ferromagnetic layer 53 can be set by applying a magnetic field to the element 5 at the time of fabrication. When the initial state of the magnetization direction is set in a direction perpendicular to the upper surface of the X-ray modulation means 10 (the length direction of the columnar element 5), a voltage is applied between the lower electrode 4 and the upper electrode 6 by the magnetization reversal current injection means 12. Is applied, the magnetization direction of the spin-free ferromagnetic layer 53 is changed either upward or downward in the direction perpendicular to the upper surface of the X-ray modulation means 10 (the length direction of the columnar element 5) (inversion). ) Will be. As the spin-free ferromagnetic layer 53, GdFe, FePt, PtCo, FeNi, or the like can be used.
Further, in order to increase the difference in the absorptance of the monochromatic circularly polarized X-ray beam B2 due to the reversal of the magnetization direction, the monochromatic circularly polarized X-ray beam B2 is X-ray modulated in accordance with the magnetization direction of the spin-free ferromagnetic layer 53. Incidently perpendicular to the upper surface of the means 10.

In addition, the material used for the spin-free ferromagnetic layer 53 can reduce the current required for the spin injection magnetization reversal, so that the relaxation time of the spin precession is large with the low saturation magnetization and the low damping constant, and the spin current is increased. Those having special characteristics are preferred. Further, from the viewpoint of the magnitude of the difference in X-ray absorptance due to magnetization reversal, the material is determined based on the energy of the X-ray used, the element excited in the spin-free ferromagnetic layer 53, the absorptance due to the element, and the like. be able to.
The film thickness of the spin-free ferromagnetic layer 53 is about several tens of nm. The spin-free ferromagnetic layer 53 can be formed on the nonmagnetic intermediate layer 52 by MBE or sputtering.

Here, a specific example of the difference between the magnetization direction and the X-ray absorption rate of the material used for the spin-free ferromagnetic layer 53 will be described.
The X-ray absorptance of the spin-free ferromagnetic layer 53 is determined by determining the incident X-ray energy and the polarity of circularly polarized light, the incident direction of the monochromatic circularly polarized X-ray beam B2 with respect to the element 5 and the magnetization of the spin-free ferromagnetic layer 53. It is determined by the relative angle between the direction and the thickness and constituent elements of the spin-free ferromagnetic layer 53. The energy of the monochromatic circularly polarized X-ray beam B2 is selected so as to correspond to the inner shell excitation energy indicating the magnetic circular dichroism of the element of the ferromagnetic material constituting the spin-free ferromagnetic layer 53, and the spin-free ferromagnetic layer When the magnetization direction of 53 is made parallel or antiparallel to the incident direction of the monochromatic circularly polarized X-ray beam B2, the ratio of the absorption coefficient to the monochromatic circularly polarized X-ray beam B2 becomes the largest, and the largest intensity modulation amplitude Can be obtained.

  In addition, as described above, in the LIGA process, suitable X-ray energy varies depending on the thickness of the resist film to be processed, and (1) a region of 500 eV to 2 keV is a high-precision fine processing for a resist having a film thickness of 5 μm or less, (2) The region of 2 keV to 5 keV is finely processed with nm order accuracy for a resist having a film thickness of 50 μm or less, and (3) the region of 5 keV to 15 keV is finely processed with micrometer order accuracy for a resist having a thickness of 1 mm or less, (4) In the region of 15 keV or higher, resist processing with a film thickness of the order of cm is considered suitable.

Accordingly, ferromagnetic materials such as FeNi and PtCo are conceivable as materials suitable for the spin-free ferromagnetic layer 53. Since the inner shell excitation energy (L ₂ level) showing magnetic circular dichroism of the former material is Fe: 0.721 keV and Ni: 0.871 keV, 0.871 keV is selected as the energy of the X-ray to be modulated. By doing so, it is possible to use the maximum difference in absorption rate with respect to the magnetization reversal of both elements Fe and Ni. That is, it can be said that it is a typical material suitable for the soft X-ray spatial modulation device in the region (1) described above.

On the other hand, since the inner shell excitation energy (L ₂ level) showing the magnetic circular dichroism of the latter material is Pt: 13.3 keV and Co: 0.793 keV, the energy of the X-ray to be modulated is 13.3 keV. By selecting, it is possible to use the difference in absorption rate mainly corresponding to the magnetization reversal of Pt. That is, it can be said that it is a typical material suitable for the hard X-ray spatial modulation device in the region (3) described above. Since the contribution of the X-ray absorption of Co of this energy is small, in this case, it can be considered only by the Pt absorption rate difference.

FIG. 4 shows the relationship between the material thickness of the spin-free ferromagnetic layer 53, which is a magnetization switching layer, and the transmittance of circularly polarized X-rays, with Fe _0.22 Ni _0.78 and PtCo as examples. The case of the composition of Pt _0.5 Co _0.5 is shown. This is a calculation result for both the case where the magnetization direction of the spin-free ferromagnetic layer 53 is parallel to the incident direction of X-rays (when the absorption rate is small) and the case where it is anti-parallel (when the absorption rate is high). Here, the ratio of the absorption rates of both was assumed to be 1.2.

From FIG. 4, it can be seen that when X-rays having energy of 0.871 keV are intensity-modulated using Fe _0.22 Ni _0.78 , intensity modulation of about 10% can be achieved at a thickness of 30 nm. However, the absolute intensity of X-rays after transmission decreases to about 60% as the net contribution of the spin-free ferromagnetic layer 53 to the intensity of incident X-rays.
On the other hand, in the case where the intensity of X-rays having energy of 13.3 keV is modulated by transmission using Pt _0.5 Co _0.5 , it can be seen that modulation is hardly possible with a thickness of 30 nm.
The thickness of the spin-free ferromagnetic layer 53 needs to be set from both absolute intensity and intensity modulation amplitude. Also, it should be noted that the necessary magnetization reversal current increases as the thickness increases due to the mechanism of magnetization reversal by spin injection.

Returning to FIG. 2, the insulating layer 3 is a layer that electrically and magnetically isolates the elements 5 from each other. The insulating layer 3 can be formed using an insulating material such as SiO ₂ , Al ₂ O ₃ , or AlN.
As a method of manufacturing the insulating layer 3, first, the spin-fixed ferromagnetic layer 51, the nonmagnetic intermediate layer 52, and the spin-free ferromagnetic layer 53 constituting each element 5 are stacked, and at least the spin-free strength is between each element 5. Lattice-like grooves are formed by mesa etching up to the magnetic layer 53 by lithography or the like. Then, the insulating layer 3 can be formed by depositing the above-described insulating material in the lattice-like grooves by the MBE method or the sputtering method. Note that the insulating layer 3 may be left in the gap without filling the lattice-shaped grooves with the insulating material.
Further, instead of the above-described mesa etching, ions such as nitrogen may be locally implanted between the elements 5 so that the insulating layer 3 can be formed by being partially insulated.

  The lower electrode 4 provided between the substrate 2 and the spin-fixed ferromagnetic layer 51 injects polarized spin electrons into the spin-free ferromagnetic layer 53 together with the upper electrode 6 provided on the spin-free ferromagnetic layer 53. An electrode for spin injection is configured. A current for magnetization reversal (magnetization reversal current) is applied to the spin-free ferromagnetic layer 53 by applying a voltage between the lower electrode 4 and the upper electrode 6 with the lower electrode 4 negative and the upper electrode 6 positive. Is injected. As a result, spin is injected into the spin-free ferromagnetic layer 53 and the magnetization direction of the spin-free ferromagnetic layer 53 is reversed. If a voltage is applied in the positive and negative directions after the magnetization reversal by spin injection, the magnetization direction of the spin-free ferromagnetic layer 53 is reversed again and returns to the previous magnetization direction.

  Further, as shown in detail in FIG. 3, the lower electrode 4 and the upper electrode 6 are respectively arranged in the X-axis direction (horizontal direction in FIG. 3) and Y-axis direction (FIG. 3) of the elements 5 arranged in a two-dimensional array. XY electrode array corresponding to the vertical direction in FIG. .., Xn constituting the lower electrode 4 and Y electrode rows Y1, Y2,..., Yn constituting the upper electrode 6 are respectively the magnetization reversal current injection means 12 (see FIG. 1). , And X electrode rows X1, X2,..., Xn and Y electrode rows Y1, Y2,..., Yn, respectively, and one or more X electrode rows X1, X2,. A voltage is applied by the magnetization reversal current injection means 12 between the Xn and Y electrode rows Y1, Y2,. Then, the X electrode rows X1, X2,..., Xn to which the voltage is applied by the magnetization reversal current injection means 12 and the element 5 arranged at the position where the Y electrode rows Y1, Y2,. A magnetization reversal current is injected, and the magnetization direction of the spin-free ferromagnetic layer 53 of the element 5 is reversed.

In this manner, the element selection unit 11 (see FIG. 1) appropriately selects the element 5 and sets the magnetization direction for each element 5, thereby allowing the X-ray modulation unit 10 to transmit the monochromatic circularly polarized X-ray beam B2. It is possible to form a pattern in which the absorptance with respect to is two-dimensionally spatially distributed. In FIG. 3, the element 5 </ b> A shown in white shows a state in which the magnetization direction of the spin-free ferromagnetic layer 53 is opposite to the magnetization direction of the spin-fixed ferromagnetic layer 51 and the absorptance is small. In addition, the element 5B shown by shading shows a state in which the magnetization direction of the spin-free ferromagnetic layer 53 is the same as the magnetization direction of the spin-fixed ferromagnetic layer 51 and the absorptance is large. The X-ray modulation means 10 shown in FIG. 3 forms a pattern in which the absorptance of the element 5 in the circular region 50 is small and the absorptance of the element 5 in other regions is large.
By transmitting the monochromatic circularly polarized X-ray beam B2 to the X-ray modulation means 10 in which this pattern is formed, the X-ray component transmitted through the circular region 50 is relatively more than the X-ray component transmitted through the other region. It is possible to obtain a modulated X-ray beam B3 that is modulated so that the intensity is increased.

  In addition, by controlling the magnetization direction of each element 5 in a time-sharing manner, the accumulated amount of X-rays transmitted within a unit time can be controlled in multiple stages. Thereby, not only two-step intensity modulation according to the magnetization direction of the element 5 but also substantially multi-step intensity modulation can be performed.

  The lower electrode 4 can be formed by depositing a metal material on the substrate 2 by a sputtering method or the like and processing the electrode bus to a desired size by a lithography method or the like. The lower electrode 4 preferably has a lower absorptance with respect to X-rays to be used, and Al, conductive graphite (C), Be, or the like can be used.

  Similarly to the lower electrode 4, the upper electrode 6 can be formed by depositing a metal material by a sputtering method or the like and processing it into an electrode bus of a desired size by a lithography method or the like. The upper electrode 6 is preferably made of a material having a low absorptance with respect to the X-rays used in order to make the monochromatic circularly polarized X-ray beam B2 efficiently enter the spin-free ferromagnetic layer 53. For example, Al, conductive graphite (C), Be, or the like can be used.

The element selection unit 11 selects the element 5 that reverses the magnetization direction and controls the magnetization reversal current injection unit 12 to inject a magnetization reversal current into the selected element 5. As a result, the magnetization direction of the spin-free ferromagnetic layer 53 of the selected element 5 is reversed. That is, the element selection means 11 controls the magnetization direction of the spin-free ferromagnetic layer 53 of each element 5 via the magnetization reversal current injection means 12.
Further, the element selection means 11 controls the magnetization direction of the spin-free ferromagnetic layer 53 of each element 5 in a time division manner, thereby substantially increasing the intensity of the monochromatic circularly polarized X-ray beam B2 transmitted through the element 5. Can be modulated.

  The magnetization reversal current injection means 12 is controlled by the element selection means 11 and corresponds to the element 5 selected by the element selection means 11 X electrode rows X1, X2,..., Xn and Y electrode rows Y1, Y2,. A voltage is applied between Yn and a magnetization reversal current is injected into the element 5. As a result, the magnetization direction of the spin-free ferromagnetic layer 53 of the element 5 is reversed.

<Operation>
Next, the operation of the X-ray spatial modulation device 1 will be described with reference to FIGS.
In the X-ray spatial modulation device 1, the element selection unit 11 appropriately selects the element 5 of the X-ray modulation unit 10 that reverses the magnetization direction. The X-ray spatial modulation device 1 includes an X electrode array X1, X2,..., Xn and an upper electrode constituting the lower electrode 4 corresponding to the element position selected by the element selection means 11 by the magnetization reversal current injection means 12. .., Yn, a voltage is applied in a direction corresponding to the magnetization direction to be reversed. As a result, a magnetization reversal current is injected into the element 5 at the position where the XY electrodes to which the voltage is applied intersect, and the magnetization direction of the spin-free ferromagnetic layer 53 of the element 5 is reversed.
The X-ray spatial modulation device 1 sets the absorptance for the monochromatic circularly polarized X-ray beam B2 in one of two stages by appropriately reversing the magnetization direction of each element 5 constituting the X-ray modulation means 10. A two-dimensional pattern image composed of the formed elements 5 is formed on the X-ray modulation means 10.
The X-ray spatial modulation device 1 makes a two-dimensional pattern image by allowing the monochromatic circularly polarized X-ray beam B2 incident from the X-ray source 20 to enter and transmit the X-ray modulation means 10 that forms the two-dimensional pattern image. Accordingly, a modulated X-ray beam B3 whose intensity is modulated in two stages is emitted.

  Since the X-ray spatial modulation device 1 according to the present invention uses the change in the absorptance due to the reversal of the magnetization direction that occurs in the order of nanoseconds, a very high operating speed can be obtained.

  Further, by utilizing the fact that the operation speed is high, the X-ray spatial modulation device 1 allows each element 5 to be appropriately time-divided by the element selection means 11 while continuously entering the monochromatic circularly polarized X-ray beam B2. By controlling the magnetization direction, the average intensity per unit time of the X-ray beam can be modulated in multiple stages. As a result, the X-ray spatial modulation device 1 can obtain an X-ray beam that is intensity-modulated substantially in multiple stages in a two-dimensional space while using the X-ray modulation means 10 whose absorption rate is variable in two stages. .

<Manufacturing method>
Next, a method for manufacturing the X-ray modulation means 10 in the X-ray spatial modulation device 1 according to the first embodiment of the present invention will be described with reference to FIGS.
First, as shown in FIGS. 5 and 12, a conductive material is deposited on the upper surface of the substrate 2 by a sputtering method or the like, and a striped lower electrode 4 is formed by a lithography method. FIG. 5 is a cross-sectional view taken along line AA ′ in FIG.

  Next, as shown in FIG. 6, the material of the spin fixed ferromagnetic layer 51 is deposited on the substrate 2 and the lower electrode 4 by MBE method, sputtering method or the like.

  Subsequently, as shown in FIG. 7, the material of the nonmagnetic intermediate layer 52 is deposited on the spin-fixed ferromagnetic layer 51 by MBE method, sputtering method, or the like.

  Further, as shown in FIG. 8, the material of the spin-free ferromagnetic layer 53 is deposited on the nonmagnetic intermediate layer 52 by MBE method, sputtering method or the like.

  Next, as shown in FIG. 9, except for the portion left as the element 5, the spin-fixed ferromagnetic layer 51, the nonmagnetic intermediate layer 52, and the spin-free ferromagnetic layer 53 are removed by mesa etching or the like by lithography, and each element is removed. A grid-like groove 30 for separating 5 from each other is provided.

Then, as shown in FIG. 10, an insulating material is deposited in the lattice-shaped grooves 30 by a sputtering method or the like to form the insulating layer 3.
Note that the lattice-shaped grooves 30 may not be filled with an insulating material, and the insulating layer 3 may be left as a gap. Further, instead of mesa etching or the like, the insulating layer 3 may be formed by locally injecting ions such as nitrogen into a portion where the groove 30 is to be provided and partially insulating.

Finally, as shown in FIGS. 11 and 13, a conductive material is deposited on the deposited spin-free ferromagnetic layer 53 by sputtering or the like, and the striped upper electrode 6 is formed by lithography. FIG. 11 is a cross-sectional view taken along line BB ′ in FIG.
Thereby, the X-ray modulation means 10 is completed.

  The spin-free ferromagnetic layer 53 in the X-ray modulation means 10 completed by the above steps has a plurality of insides so that each of the spin-free ferromagnetic layers 53 is stable in terms of magnetic energy when the spin-free ferromagnetic layer 53 is formed. Therefore, it is necessary to align the magnetization direction in a predetermined direction (upward or downward in the direction perpendicular to the substrate 2). Therefore, as an initialization operation (reset), a magnetic field of about several tens to 5 kG is externally applied to all the spin-free ferromagnetic layers 53 so that the magnetization directions are aligned in a predetermined direction. For example, the linear spin-free ferromagnetic layer 53 like the element 5 in the first embodiment may apply a magnetic field in the length direction. After this initialization, the magnetization in this magnetization direction is maintained, so that no magnetization disappears or changes until a new current is injected or a magnetic field is applied.

<Application example>
Next, an X-ray exposure apparatus 100 for X-ray lithography using the X-ray spatial modulation apparatus 1 of the first embodiment will be described with reference to FIG.
As shown in FIG. 14, an X-ray exposure apparatus 100 includes an X-ray spatial modulation apparatus 1 and an X-ray source 20, and uses the X-ray modulation means 10 of the X-ray spatial modulation apparatus 1 as an X-ray exposure mask.
Since the X-ray source 20 and the X-ray spatial modulation device 1 are the same as those shown in FIG. 2, the same reference numerals are given and detailed description thereof is omitted.
Further, the processing target 40 shown in FIG. 14 has an X-ray resist film 42 such as PMMA deposited on the upper surface of a substrate 41.

  The X-ray exposure apparatus 100 two-dimensionally modulates the intensity of the monochromatic circularly polarized X-ray beam B2 generated by the X-ray source 20 with the X-ray spatial modulation apparatus 1, and uses the modulated X-ray beam B3 that has been intensity-modulated. 40 resist films 42 are exposed. At this time, for example, by forming a circular pattern (circular region 50) as shown in FIG. 3 by the X-ray spatial modulation device 1, the region of the circular region 50 is transmitted and is relatively relative to other regions. In the region of the resist film 42 exposed to the intense modulated X-ray beam B3, a cylindrical recess is formed by development.

  The X-ray exposure apparatus 100 is an X-ray exposure mask by changing the two-dimensional pattern image formed on the X-ray modulation means 10 by time division by the element selection means 11 of the X-ray spatial modulation apparatus 1. The exposure pattern by the modulated X-ray beam B3 transmitted through the X-ray modulation means 10 can be changed in a time division manner. Thus, the X-ray exposure apparatus 100 can modulate the exposure amount for each local region having a resolution corresponding to the size of each element 5, and can process the resist film 42 in accordance with the exposure amount. For example, in the circular pattern shown in FIG. 3, the element 5 constituting the circular region 50 is controlled so as to increase the time during which the absorption rate of the element 5 is small as it is closer to the center of the circular region 50. The closer the resist film 42 is to the center of the circular pattern, the greater the exposure amount and the deeper the processing. Thereby, a conical recess can be formed in the resist film 42.

As described above, the X-ray exposure apparatus 100 can control the two-dimensional pattern image of the X-ray modulation means 10 that is an X-ray exposure mask by time division. Can do.
As a result, the X-ray exposure apparatus 100 can process a three-dimensional shape with a high degree of freedom.

  In addition, the X-ray spatial modulation device 1 according to the first embodiment of the present invention is not limited to the use for causing the X-ray modulation means 10 to function as an X-ray exposure mask, and various two-dimensional pattern images are displayed on the X-ray modulation means 10. By forming, the X-ray modulation means 10 can also function as, for example, a zone plate or a diffraction grating.

Next, an X-ray spatial modulation apparatus 1A according to a second embodiment of the present invention will be described with reference to FIGS.
The X-ray spatial modulation device 1 according to the first embodiment shown in FIG. 1 is a transmissive X-ray spatial modulation device that modulates the X-ray intensity by transmitting through the element 5. On the other hand, the X-ray spatial modulation device 1A in the second embodiment shown in FIG. 15 reflects the monochromatic circularly polarized X-ray beam B2 on the upper surface of the X-ray modulation means 10A, and spins formed on the upper layer of the element 5 The intensity of the X-ray beam is modulated by utilizing magnetic circular dichroism with respect to the reflected light whose reflectivity changes according to the magnetization direction of the free ferromagnetic layer 53.

<Configuration>
As shown in FIG. 15, the X-ray spatial modulation device 1A according to the second embodiment includes an X-ray modulation unit 10A, an element selection unit 11, a magnetization reversal current injection unit 12, and an X-ray incident angle control unit 13. I have. In addition, about the structure similar to the X-ray spatial modulation apparatus 1 in 1st Embodiment shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted suitably.

  The X-ray spatial modulation device 1A reflects the monochromatic circularly polarized X-ray beam B2 in accordance with the magnetization direction of the spin-free ferromagnetic layer 53A of each element 5A constituting the X-ray modulation means 10A on the upper surface of the X-ray modulation means 10A. A modulated X-ray beam B3, which is a reflected X-ray reflected at a rate and modulated in intensity, is emitted.

  The X-ray modulation means 10A in the second embodiment has the same configuration as the X-ray modulation means 10 in the first embodiment, but includes an element 5A instead of the element 5, and includes a spin-fixed ferromagnetic layer 51A and a spin-free strength. The magnetization direction of the magnetic layer 53A is different from the magnetization directions of the spin-fixed ferromagnetic layer 51 and the spin-free ferromagnetic layer 53 of the element 5 in the first embodiment.

The magnetization directions of the spin-fixed ferromagnetic layer 51A and the spin-free ferromagnetic layer 53A are such that the change in reflectance of the monochromatic circularly polarized X-ray beam B2 due to the reversal of the magnetization direction of the spin-free ferromagnetic layer 53A increases. It is preferably set so as to be substantially parallel or anti-parallel to the incident direction of the polarized X-ray beam B2. The magnetization direction of the spin-fixed ferromagnetic layer 51A shown in FIG. 16 is parallel to the upper surface of the substrate 2 as indicated by an arrow in the figure, and toward the upper surface of the substrate 2 in the incident direction of the monochromatic circularly polarized X-ray beam B2. Is set to be anti-parallel (reverse) to the projection of
Further, the magnetization direction of the spin-free ferromagnetic layer 53A is parallel to the upper surface of the substrate 2 as indicated by an arrow in the figure, and the incident direction of the monochromatic circularly polarized X-ray beam B2 is projected onto the upper surface of the substrate 2. Is set to be parallel or anti-parallel.
The magnetization direction of the spin-fixed ferromagnetic layer 51A may be the opposite direction (parallel to the projection of the incident direction of the monochromatic circularly polarized X-ray beam B2 on the upper surface of the substrate 2).

  The initial state of the magnetization direction of the spin-fixed ferromagnetic layer 51A and the spin-free ferromagnetic layer 53A is set by applying a magnetic field in the direction in which the magnetization direction is to be set (initialized) when the X-ray modulation means 10A is manufactured. Can do.

  The spin-free ferromagnetic layer 53 </ b> A whose magnetization direction is initially set is inverted in magnetization direction when a voltage is applied between the lower electrode 4 and the upper electrode 6. The spin-free ferromagnetic layer 53A shown in FIG. 16 is inverted either leftward or rightward in the figure according to the direction of the applied voltage.

  As the incident monochromatic circularly polarized X-ray beam B2, the monochromatic circularly polarized X-ray beam B2 generated by the X-ray source 20 shown in FIG. 1 can be used.

  The X-ray incident angle control means 13 is a control means for adjusting the incident angle θ of the incident monochromatic circularly polarized X-ray beam B2 on the upper surface of the X-ray modulation means 10.

In the reflection type modulation, the incident angle θ to the element 5 greatly affects the degree of modulation of the reflectance.
Here, with reference to FIG. 17, the relationship between the reflectance and the incident angle in the material of the spin-free ferromagnetic layer 53A when surface reflection is used will be described.

FIG. 17 shows the relationship between the reflectance and the incident angle θ in the case of the composition of Fe _0.22 Ni _0.78 and Pt _0.5 Co _0.5 as the material of the spin-free ferromagnetic layer 53A that is the magnetization switching layer. Is shown. This is a calculation result for both the case where the magnetization direction of the spin-free ferromagnetic layer 53A is parallel to the incident direction of X-rays (when the absorption rate is small) and the case where it is antiparallel (when the absorption rate is high). Here, the ratio of the absorption rates of both was assumed to be 1.2. The reflectivity of X-rays greatly depends on the incident angle θ together with the absorptance of the surface layer of the reflecting surface.

From FIG. 17, when intensity-modulating X-rays having energy of 0.871 keV using Fe _0.22 Ni _0.78 , the modulation degree is the largest when the incident angle θ is 0.04 to 0.05 rad, and is 10%. It will be about. Further, when intensity-modulating X-rays having energy of 13.3 keV using Pt _0.5 Co _0.5 , the modulation degree is the largest when the incident angle θ is 0.004 to 0.005 rad, and is about 10%. . In this calculation, it is assumed that there is no upper electrode 6. Actually, it is assumed that the central portion of the upper electrode 6 is opened and X-rays are directly reflected by the spin-free ferromagnetic layer 53A.

When these materials are used, the absolute intensity of the reflected X-rays is about 1/2 that of the incident X-rays (reflectance is about 0.5). When modulating X-rays having an energy of 13.3 keV using Pt _0.5 Co _0.5 , the degree of modulation is larger than that of the transmission type described above. Further, the intensity of the modulated X-ray with respect to the incident X-ray intensity, that is, the intensity of the reflected X-ray is large, and the utilization efficiency of the X-ray is good. Therefore, it is necessary to set the incident angle θ based on both the absolute intensity and the modulation degree.

  In the case of the reflection type, since the monochromatic circularly polarized X-ray beam B2 is incident at an extremely small incident angle θ, the beam width of the modulated X-ray beam B3 becomes narrow, and as a result, the spatial frequency of modulation becomes extremely high. Therefore, by making the modulated X-ray beam B3 incident on a diffraction crystal such as silicon and utilizing asymmetric reflection, the X-ray beam width can be expanded and the spatial frequency of the modulated X-ray beam B3 can be lowered. As a diffractive crystal for asymmetric reflection, for example, reflection by a (311) plane of silicon can be used.

<Operation>
Next, the operation of the X-ray spatial modulation device 1A in the second embodiment will be described with reference to FIG.
In the X-ray spatial modulation apparatus 1A, first, the X-ray incident angle control means 13 controls the attitude of the X-ray modulation means 10A, and the incident angle of the monochromatic circularly polarized X-ray beam B2 on the upper surface of the X-ray modulation means 10A. θ is set to a predetermined angle.

Next, the X-ray spatial modulation device 1A appropriately changes the magnetization direction of each element 5 constituting the X-ray modulation means 10 so that the reflectivity with respect to the monochromatic circularly polarized X-ray beam B2 is any of two levels. A two-dimensional pattern image made up of the elements 5 set to be formed is formed on the X-ray modulation means 10A.
In the X-ray spatial modulation device 1A according to the second embodiment, the operation for forming a two-dimensional pattern on the X-ray modulation means 10A is the same as that of the X-ray spatial modulation device 1 according to the first embodiment, and thus the description thereof is omitted. To do.

  The X-ray spatial modulation device 1A uses an incident monochromatic circularly polarized X-ray beam B2 as a spin-free ferromagnetic layer 53A of an element 5A that is the upper surface of the X-ray modulation means 10A that forms the two-dimensional pattern image (see FIG. 16). The modulated X-ray beam B3, which is intensity-modulated in two steps according to the two-dimensional pattern image, is emitted by being reflected at.

  Since the X-ray spatial modulation device 1A according to the present invention uses the change in reflectance due to the reversal of the magnetization direction, a very high operating speed can be obtained.

  Further, the X-ray spatial modulation device 1A, like the X-ray spatial modulation device 1 in the first embodiment, appropriately changes the magnetization direction of each element 5 in a time division manner, thereby averaging the X-ray beam per unit time. The intensity can be modulated in multiple steps. As a result, the X-ray spatial modulation device 1A can obtain an X-ray beam that is intensity-modulated two-dimensionally in multiple stages using the X-ray modulation means 10A having a variable reflectance in two stages.

  Since the X-ray modulation means 10 of the X-ray spatial modulation device 1A in the second embodiment can be manufactured in the same manner as the X-ray modulation means 10 of the X-ray spatial modulation device 1 in the first embodiment, description thereof is omitted. To do.

  In addition, the X-ray spatial modulation device 1A in the second embodiment can be used as an X-ray exposure mask, a zone plate, a diffraction grating, and the like, similarly to the X-ray spatial modulation device 1 in the first embodiment.

DESCRIPTION OF SYMBOLS 1, 1A X-ray spatial modulation apparatus 2 Substrate 3 Insulating layer 4 Lower electrode 5, 5A Spin injection magnetization reversal element (element)
6 Upper electrode 10, 10A X-ray modulation means (X-ray exposure mask)
DESCRIPTION OF SYMBOLS 11 Element selection means 12 Magnetization reversal current injection means 13 X-ray incident angle control means 20 X-ray source 21 Synchrotron radiation light source 22 Monochromator 23 Wavelength selection means 24 Phase shifter 25 Polarity selection means 30 Groove 40 Processing object 41 Substrate 42 Resist Film 50 Circular region 51, 51A Spin-fixed ferromagnetic layer (magnetization direction fixed layer)
52 Nonmagnetic intermediate layer (intermediate layer)
53, 53A Spin-free ferromagnetic layer (magnetization direction variable layer)
100 X-ray exposure apparatus B0 White linearly polarized X-ray beam B1 Monochromatic linearly polarized X-ray beam B2 Monochromatic circularly polarized X-ray beam B3 Modulated X-ray beam

Claims (7)

An X-ray spatial modulation device that enters a monochromatic circularly polarized X-ray beam, which is a monochromatic circularly polarized X-ray beam, and modulates the intensity distribution of the incident monochromatic circularly polarized X-ray beam in a two-dimensional space,
X-ray modulation means in which spin injection type magnetization reversal elements whose magnetization directions are reversed by spin injection are two-dimensionally arranged;
Element selecting means for selecting the spin injection type magnetization reversal element for reversing the magnetization direction from the two-dimensionally arranged spin injection type magnetization reversal elements;
A magnetization reversal current that inverts the magnetization direction of the spin injection type magnetization reversal element by injecting a magnetization reversal current that is a current for reversing the magnetization direction into the spin injection type magnetization reversal element selected by the element selection means. An injection means,
The element selection means controls the magnetization direction of the spin-injection type magnetization reversal element through the magnetization reversal current injection means to change the absorptance of the spin-injection type magnetization reversal element with respect to the monochromatic circularly polarized X-ray beam. Thereby, the intensity of the monochromatic circularly polarized X-ray beam incident on the spin-injection magnetization switching element and transmitted through the spin-transfer magnetization switching element is modulated. An X-ray spatial modulation device that enters a monochromatic circularly polarized X-ray beam, which is a monochromatic circularly polarized X-ray beam, and modulates the intensity distribution of the incident monochromatic circularly polarized X-ray beam in a two-dimensional space,
X-ray modulation means in which spin injection type magnetization reversal elements whose magnetization directions are reversed by spin injection are two-dimensionally arranged;
Element selecting means for selecting the spin injection type magnetization reversal element for reversing the magnetization direction from the two-dimensionally arranged spin injection type magnetization reversal elements;
A magnetization reversal current that inverts the magnetization direction of the spin injection type magnetization reversal element by injecting a magnetization reversal current that is a current for reversing the magnetization direction into the spin injection type magnetization reversal element selected by the element selection means. An injection means,
The element selection means controls the magnetization direction of the spin injection type magnetization reversal element through the magnetization reversal current injection means to change the reflectivity of the spin injection type magnetization reversal element with respect to the monochromatic circularly polarized X-ray beam. To modulate the intensity of the monochromatic circularly polarized X-ray beam incident on the spin-injection magnetization reversal element and reflected by the spin-injection magnetization reversal element. The X-ray modulation means includes a substrate, a plurality of lower electrodes arranged in a stripe shape on the substrate, and a plurality of upper electrodes arranged in a stripe shape in a direction perpendicular to the lower electrode,
In a region where the lower electrode and the upper electrode intersect in plan view, both ends of the spin injection type magnetization reversal element are disposed in electrical connection with the lower electrode and the upper electrode,
The magnetization reversal current injection means is configured to apply a voltage between the lower electrode and the upper electrode, whereby the spin injection magnetization reversal element disposed between the lower electrode and the upper electrode to which the voltage is applied. The X-ray spatial modulation device according to claim 1, wherein the magnetization reversal current is injected into the X-ray spatial modulation device. The spin-injection type magnetization reversal element is composed of a non-magnetic material and a magnetization direction fixed layer made of a ferromagnetic material whose magnetization direction is fixed in order from the lower electrode side between the lower electrode and the upper electrode. A laminated columnar structure in which an intermediate layer and a magnetization direction variable layer made of a ferromagnetic material whose magnetization direction is reversed by injection of the magnetization reversal current are laminated;
The spin injection type magnetization reversal elements are arranged upright on the substrate, and the adjacent spin injection type magnetization reversal elements are electrically and magnetically insulated from each other by an insulating layer. The X-ray spatial modulation device according to claim 3. 5. The X-ray spatial modulation device according to claim 4, wherein the intensity of the monochromatic circularly polarized X-ray beam having a wavelength corresponding to an inner-shell electron binding energy of an element constituting the magnetization direction variable layer is modulated.   6. The X-ray according to claim 1, wherein the element selection unit performs time-division selection of the spin injection type magnetization reversal element for reversing the magnetization direction. Spatial modulation device. An X-ray source generating a monochromatic circularly polarized X-ray beam;
An X-ray spatial modulation device according to any one of claims 1 to 6,
An X-ray exposure apparatus characterized in that a monochromatic circularly polarized X-ray beam generated by the X-ray source is intensity-modulated by the X-ray spatial modulation apparatus, and the modulated X-ray subjected to the intensity modulation is used as an X-ray for exposure.

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