JP5568426B2 - Thin film laminate inspection method - Google Patents

Description

  The present invention relates to a method for nondestructively measuring and inspecting the film thickness of each layer of a thin film laminate that is laminated on a substrate by one or more layers. The present invention relates to an X-ray reflectometry method for measuring line phase information.

  In the field of semiconductor devices and magnetic devices, the formed films are made extremely thin and the number of stacked layers is increasing in order to increase the functionality and performance of elements. In addition, in current electronic devices such as semiconductors and magnetic devices, roughness control at the laminated film interface is also being studied in order to control electron scattering at the laminated film interface.

  Conventionally, ellipsometry and fluorescent X-ray methods have been used as methods for evaluating the film thickness of a laminated film. The ellipsometry method is a method in which polarized light is incident on a thin film sample having a flat surface, the change in the polarization state of reflected light is measured, and the thickness and refractive index of the sample thin film are known. However, since this method uses light, there is a problem in that measurement is only possible for a sample that is transparent to light. The fluorescent X-ray method is a method of measuring a fluorescent X-ray generated in a sample and estimating a film thickness from the intensity. In the case of this method, the total amount of elements that generate fluorescent X-rays is known, and it is not a method for directly measuring the film thickness, and when a plurality of thin films containing the same element are laminated, the film thickness is analyzed separately. The inability to do so is a problem. In addition, neither the ellipsometry method nor the fluorescent X-ray method can obtain information on the interface of the laminated film.

  The cross-sectional TEM observation of the device can measure the film thickness of the laminated film with very high spatial resolution. The interface width can also be estimated. However, for TEM observation, it is necessary to slice the sample to 100 nm or less, which is a fracture analysis. Further, it is necessary to observe a cross section by irradiating an electron beam perpendicularly to the surface at the time of observation. Since this angle alignment accuracy is larger than 0.1 °, the film thickness measurement accuracy is limited to about 0.2 nm.

  As a method for measuring the film thickness and interface width of a laminated thin film in a nondestructive manner, there is an X-ray reflectivity method. There are two types of X-ray reflectivity methods for measuring the reflection intensity. One is a method in which monochromatic X-rays are incident on the surface of the sample and the reflectance is measured while changing the incident angle, and the other is white. In this method, X-rays are incident on a sample and the wavelength dependence of the reflectance is measured. Both methods analyze the film thickness from the interference of X-rays reflected from the sample surface and interface. In addition, since the interface width affects the reflection at the surface and the interface, the width of each interface of the laminated film can be obtained by analyzing the X-ray reflectance profile in detail. As the theoretical curve used for the analysis of the reflectance, a formula obtained by adding the effect of the interface irregularity of Non-Patent Document 2 to the recurrence formula of Non-Patent Document 1 is used. In Fourier transform analysis, the method of Non-Patent Document 3 is often used. Wavelet method and entropy maximization method (MEM) are studied as new reflectance analysis methods, and X-ray differential reflectance method and X-ray phase reflectance method (Patent Document 1) are being studied as reflectance measurement methods. .

JP 2009-168618

Parratt [Phys. Rev., 95, pp359 (1954)] Sinha etc [Phys. Rev. B, 38, pp2297 (1988)] Sakurai et al. [Jpn. J. Appl. Phys. 31, L113 (1992)]

  In the field of semiconductor / magnetic devices, miniaturization is being promoted in addition to ultra-thin multi-layered films as elements have higher functions and higher performance. The X-ray reflectivity method is an excellent method capable of evaluating the film thickness and interface width of each layer of the laminate, but is not good at evaluating the film thickness and interface width of a micro area of the sample. Since the X-ray reflectivity method requires that X-rays be incident on the sample surface, the irradiation area of incident X-rays extends to an area 10 to 100 times the size of the irradiation X-rays. For this reason, a beam size of 10 μm or less is required for measuring the X-ray reflectivity in a region of 1 mm or less. Further, in the X-ray reflectivity method, it is necessary to adjust the positional relationship between the sample and the irradiated X-ray to be suppressed to 1/10 or less of the beam size. Although the sample surface can be aligned with an accuracy of 1 μm or less even for an X-ray beam of 10 μm or less, the positional relationship between the irradiation position, X-rays, and the sample surface must be maintained with an accuracy of 1 μm or less while changing the incident angle. It is difficult. Because of these problems, it is difficult to measure the film thickness of a minute region by the X-ray reflectivity method.

  Therefore, the present invention irradiates the laminated sample with incident X-rays condensed to 10 μm or less, and measures the phase information of the reflected X-rays, so that the film of a minute region can be obtained without rotating the laminated sample. The object is to provide an X-ray reflectivity method capable of measuring and inspecting the thickness.

  As an example of the present invention for solving the above-described problems, incident X-rays are incident on the upper half of the upstream X-ray lens, and are amplitude-divided into primary X-rays to be collected and zero-order light to be transmitted. The sample placed at the focal point of the light X-ray is specularly reflected, and the reflected X-rays with continuous reflection angles are made object waves, and the zero-order light is interfered with the reference wave and the downstream X-ray lens, and the interference fringes are two-dimensional. The phase of the reference wave is modulated using the phase plate placed in the optical path of the 0th order light measured by the detector, the phase of the reflected X-rays at successive reflection angles is measured, and the reflected X due to the difference in the incident angle The film thickness is measured from the phase change of the line.

  According to the present invention, the X-rays condensed to 10 μm or less by the X-ray condenser lens are incident on the laminated body, and the X-ray phase reflectivity of the reflected X-rays is measured, whereby each layer of the laminated body microregion The film thickness can be inspected with the incident angle fixed.

Examples of the present invention Another embodiment of the present invention Still another embodiment of the present invention Another embodiment of the present invention Transmission type Laue lens used in the present invention Fresnel zone plate used in the present invention

  The feature of the present invention that achieves the above object is that an X-ray lens is used as an amplitude division beam splitter and a condensing optical system. The X-ray refracted by the X-ray lens has an angular distribution that is condensed at the focal position. The angle distribution of incident X-rays is controlled by irradiating only a part of the X-ray lens with X-rays. When the thin film stack disposed at the focal position is irradiated with condensed X-rays, it is specularly reflected, and reflected X-rays corresponding to the angular distribution of incident X-rays are obtained. The X-rays that are transmitted without being refracted by the X-ray lens are superimposed as a reference wave, and the X-rays reflected by the thin film stack are superposed by an X-ray lens arranged downstream of the thin film stack.

  The superimposed X-rays interfere with each other, producing interference fringes reflecting the optical path difference and the phase difference generated in the thin film stack. Next, using the phase plate arranged in the optical path of the reference wave, the phase of the reference wave is changed from 0 to 2π to measure the interference fringes. . The phase of the object wave is analyzed from the interval between the fringes and the positional deviation.

Further, the incident X-ray is divided into wavefronts by irradiating the X-ray lens with a part of the incident X-ray. The X-ray irradiated to the X-ray lens is refracted and condensed at the focal position, but the angle distribution of the incident X-ray is controlled by limiting the region irradiated to the X-ray lens. When the thin film stack disposed at the focal position is irradiated with condensed X-rays, it is specularly reflected, and reflected X-rays corresponding to the angular distribution of incident X-rays are obtained.
The X-rays that have not passed through the X-ray lens are superimposed on an X-ray camera arranged as a reference wave and the X-rays reflected by the thin film stack as an object wave on the downstream side of the thin film stack. The superimposed X-rays interfere to obtain interference fringes reflecting the optical path difference and the phase difference generated in the thin film stack, and the phase of the reference wave is set to 0 using a phase plate arranged in the optical path of the reference wave. The interference fringes are measured while changing from 2 to 2π. . The phase of the object wave is analyzed from the interval between the fringes and the positional deviation.

Next, a film thickness analysis method will be described. When the film thickness is small, the X-ray reflected by the substrate and the X-ray reflected by the surface of the laminated film are included in the object wave by setting the incident angle θ of the X-ray to be larger than the total reflection critical angle. In this case, the amount of deviation between the interference fringes in the region reflected by the substrate portion and the interference fringes in the region reflected by the laminated film portion is measured. The optical path difference Δ between the X-ray reflected from the sample surface and the X-ray reflected from the substrate can be expressed by Equation 1 where the incident angle is θ and the film thickness of the laminated film is d.
Δ = 2d sinθ (Equation 1)
Where the phase difference between the object beam on the detector is in the 2nπ the position Z _1, the formula 2 when the incident angle and the incident angle theta _1. The correlation between θ and Z must be determined in advance.
2nπ = 4π (d / λ) sinθ ₁ (Equation 2)
Next, a position Z ₂ on the detector having a phase difference of 2 (n + 1) π is obtained, and assuming that the incident angle is the incident angle θ ₂ , 2 (n + 1) π = 4π (d / Λ) sinθ ₂ (Equation 3)
Subtracting Equation 2 from Equation 3 yields Equation 4.
2π = 4π (d / λ) (sinθ ₁ −sinθ ₂ )
d ≒ λ / {2Δθcos (θ _av )} (Equation 4)
In equation 4, θ _av is the average value of the two incident angles measured, and Δθ is the difference between the two incident angles.

Next, a method for analyzing a multilayer laminate will be described. Interference fringes are measured by changing the incident angle θ to the sample from an angle smaller than the total reflection critical angle to about 1 °. Measure the amount of deviation between the interference fringes of the area reflected by the substrate part of the obtained interference fringes and the interference fringe of the area reflected by the laminated film part, and the position of the X-rays reflected by the substrate and the laminated film part. Find the phase difference. This is performed for every measurement incident angle, and the incident angle dependence is obtained in the phase change of the laminated film portion. Parratt [Phys. Rev., 95, pp359 (1954)] presents the recursion formula for the reflectivity curve of the X-rays specularly reflected by the laminated film. The incident angle to the laminate is θ, the wavelength of the incident X-ray is λ, the film thickness of the j-th layer of the laminate is d _j , and the refractive index is n = 1 − (δ _j + i · β _j ) = 1− If {λ / (4π)} ² (ξ + i · η),
R _j = a _j ⁴ · [(R _{j + 1} + F _{j, j + 1} ) / (R _{j + 1} · F _{j, j + 1} )] (Equation 5)
γ _j ² = q ² over _{2 (ξ j - iη j)} ( 6)
a _j = exp [-i · γ _j · d _j / 4] (Equation 7)
F _{j, j + 1} = {(γ _j -γ _{j + 1} ) / (γ _j + γ _{j + 1} )} (Equation 8)
Can be used to calculate. Usually, since the X-ray reflectivity is measured by intensity, | R ₁ | ² is obtained, but when a phase reflectometer is used, the phase of the reflected X-ray is obtained, so R ₁ is calculated. This can be compared with the experimental value. Equation 3 can be approximated as γ _j ≈q in the region of q ² >> ξ and q ² >> η, and | R _{j + 1} · F _{j, j +1} | << 1. 10 can be written.
R _j = a _j ⁴・ (R _{j + 1} + F _{j, j + 1} ) (Equation 9)
R ₁ = Σ ¹ _{j = N + 1} [{II ¹ _{k = j} (a _k ⁴ )} · F _{j, j + 1} ] (Equation 10)
F _{j and j + 1} are Fresnel reflection coefficients, representing the amplitude of the reflected wave, and a _k representing the phase. From Equation 9, it can be seen that the phase reflectivity R ₁ is the sum of X-ray waves reflected at each interface. By applying the phase information measured by changing the incident angle to Equation 9, the phase of the X-ray reflected at each interface can be obtained, and a _j can be solved by simultaneous equations. Thereby, the film thickness of the film layer can be obtained. As described above, by using the phase reflectance method using the condensed X-ray of the present invention as incident light, the incident angle of the thin film stack can be changed without changing the incident angle. It is possible to inspect the film thickness in a minute region.

Details of an example in which the above-described method is actually applied will be described below.
(Example 1)
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In this example, the transmission type Laue lens shown in FIG. 6 was used as the upstream X-ray lens 3 and the downstream X-ray lens 10. The size of the transmissive Laue lens was about 1 mm square, and the focal length for X-rays with a wavelength of 0.1 nm was 50 mm. FIG. 6 shows two types of transmission type Laue lenses. The right figure is composed only of the upper half of the transmission type Laue lens shown in the left figure. In carrying out the present invention, the left-side transmissive Laue lens is used for ease of adjustment.
However, since only the upper half of the transmission type Laue lens is used in actual measurement, the same effect can be obtained even with the transmission type Laue lens as shown in the right figure. X-rays using the undulator radiation source of the Synchrotron Radiation Research Facility (SPring-8) at the High-intensity Photonics Research Center as an X-ray source are monochromatized into 0.1-nm wavelength X-rays by a monochromator and reflected by a high-order light removal mirror The slit was molded in the z direction to 10 μm and the x direction to 10 μm. Using a center stop (not shown), the X-ray at the center of the upstream X-ray lens 3 was removed, and higher-order diffracted light 6 other than the first-order diffracted light 5 was removed by OSA (Order Selecting Aperture: not shown). . Next, the downstream X-ray lens 10 was inserted, the position was adjusted while confirming with the two-dimensional detector 12 so that the entire surface of the downstream X-ray lens 10 was irradiated with the first-order diffracted light 5, and recording data 1 was recorded.
At this time, the X-ray width in the direction perpendicular to the paper surface was limited to 20 μm. Next, the center stop (not shown) and OSA (not shown) are removed, and the incident slit 2 is made to have the first-order diffracted light 5 so that the incident X-ray 1 is irradiated only to the upper half of the upstream X-ray lens 3. The position and width were adjusted so that the condensing angle width was 0.11 to 0.57 °. As a result of the adjustment, the slit width in the vertical direction on the paper surface became 400 μm.

  In this optical arrangement, the X-ray at the focal position was about 0.1 μm × 25 μm. Next, the high-order diffraction light 6 was removed using the high-order diffraction removal slit 7, and the zero-order light 4 that was not refracted by the upstream X-ray lens 3 was removed using the knife edge 14. As a result, only the lower side of the downstream X-ray lens 10 is irradiated with X-rays (shown by broken lines). This irradiation range was recorded as recording data 2 by the two-dimensional detector 12. The condensing angle width of the first-order diffracted light 5 is an incident angle range of the incident X-ray to the sample. Next, the knife edge 14 was removed, and a sample 8 having a silicon oxide film of about 10 nm formed on a silicon thin plate was placed at the focal position. The reflected X-ray 9 reflected from the sample was refracted by the downstream X-ray lens 10 and superimposed with the zero-order light 4. The positions of the pre-recorded recording data 1 and recording data 2, the first-order diffracted light 5, the 0th-order light 4, and the reflected X-ray 9 are matched so that the overlapping of the reflected X-ray 9 and the 0th-order light 4 accurately matches. As described above, the swivel 2 axis and the Z axis (not shown) of the sample 8 were driven and adjusted.

  Further, the measurement position of the sample and the X-ray irradiation position were matched by driving an XY axis (not shown) so that incident X-rays were irradiated to the measurement region. During adjustment, the interference fringes obtained by superimposing the reflected X-ray 9 and the zero-order light 4 are obstructed, so that the knife edges 14 and the Z axis (not shown) of the sample 8 are used so that no interference fringes appear. The overlap of the reflected X-ray 9 and the 0th-order light 4 was confirmed and adjusted.

  When the knife edge 14 is removed after the adjustment is completed, the interference X-ray 11 is obtained, and the intensity distribution of the interference X-ray 11 is recorded by the two-dimensional detector 12. At this time, the X-ray irradiation area on the sample was 50 μm × 25 μm.

Next, in order to shift the phase of the 0th-order light 4 as the reference wave, the phase plate 13 was tilted and the interference fringes were measured by the two-dimensional detector 12.
In the optical system of the present invention, the interference fringes generated by the optical path difference between the reference wave and the object wave have a very short period, and therefore cannot be detected by the two-dimensional detector 12 having a resolution of several μm. The obtained interference fringes reflect the phase difference due to the difference in the incident angle of the object wave reflected by the sample. By measuring the interference fringes with the two-dimensional detector 12 while changing the phase of the reference wave with the phase plate 13, the extreme value of the amplitude of the object wave and the coordinates of the nodes were obtained. The origin coordinates were obtained from the positional relationship between the recorded data 2 and the reflected X-ray 9 on the detector excluding the reference wave at the knife edge 14. The incident angle was determined from the extreme value from the origin, the coordinates of the nodes, and the focal point position—the distance from the downstream X-ray lens 10. When the parameters obtained from the recording data are applied to Equations 2 to 4, the film thickness of the laminated film can be obtained. In the example, θ = 0.280 °, an extreme value at 0.57 °, and a node at 0.423 ° were measured. Since the relationship between the extreme value and the node is shifted in phase by π, Equation 4 is corrected to the following Equation 11: π = 4π (d / λ) (sinθ ₁ −sinθ ₂ )
d≈λ / {4Δθcos (θ _av )} (Equation 11)
Using the incident angle given by the extreme value, the film thickness was determined from Equation 4 to be d = 9.88 nm.
Further, when the film thickness was obtained from Equation 4 using the incident angle giving the extreme value and the node, d = 10.2 nm and 97.5 nm were obtained, and from these results, the film thickness could be obtained as 99.4 nm. .

  Next, a case where the thickness of the sample is thick or a case where an interference fringe caused by the optical path difference between the reference wave and the object wave is detected will be described with reference to FIG. A feature of the embodiment shown in FIG. 2 is that there is an magnifying X-ray lens 15 between the downstream X-ray lens 10 and the two-dimensional detector 12. The magnifying X-ray lens 15 used was a concentric Fresnel zone plate (FIG. 6) having a focal length of 150 mm for X-rays having a wavelength of 0.1 nm.

If the distance between the downstream X-ray lens 10 and the magnifying X-ray lens 15 is 135 mm, the distance between the magnifying X-ray lens 15 and the two-dimensional detector 12 is 1350 mm, which is above the downstream X-ray lens 10. The interference fringes were magnified about 10 times and projected onto the two-dimensional detector 12. In this embodiment, the interference fringes are magnified by the magnifying X-ray lens 15, but the field of view is limited due to the influence of the center stop for the magnifying X-ray lens 15 and OSA (not shown).
However, it was possible to detect interference fringes with a short cycle when the sample was thick and interference fringes caused by the optical path difference between the reference wave and the object wave.
(Example 2)
The following example is shown in FIG. The interference fringes generated by the optical path difference between the reference wave and the object wave that cannot be detected in the embodiment shown in FIG. 1 include information on the collection angle / divergence angle distribution of incident X-rays. By measuring this interference fringe, the incident angle of the interference fringe from the sample to be measured can be accurately obtained. Therefore, in the embodiment shown in FIG. 3, the wedge-shaped phase plate 16 is inserted in the optical path of the reference wave, the optical path of the reference wave is inclined, and the interval between the interference fringes generated by the interference between the object wave and the reference wave having different converging angles. It is characterized by the fact that it has been expanded. Actually, rotate the wedge-shaped phase plate 16 to change the phase of the reference wave, observe the interference fringes with the two-dimensional detector 12, replace the wedge-shaped phase plate 16 with a phase plate with a different wedge angle, and replace the interference fringes. Repeat the observation to give the optimum phase shift. Since the angle range of incident X-rays in this embodiment is 0.11 to 0.57 °, the wedge-shaped phase plate 16 is adjusted so that about 50 interference fringes are detected.

In the embodiments so far, X-rays are divided by amplitude division in the vertical direction on the drawing, and the direction perpendicular to the paper surface is limited to 20 μm by the entrance slit. X-rays at the focal point are focused to about 100 nm × 25 μm, but spread to 50 μm × 25 μm by oblique incidence on the sample surface. The main object of the present invention is to measure the film thickness in the region of 50 μm using 100 nm focused X-ray, but the resolution can be improved if the direction is perpendicular to the paper surface. The upstream X-ray lens 3 and the downstream X-ray lens 10 of the embodiment shown in FIGS. 1 to 3 are replaced with the concentric Fresnel zone plate shown in FIG. 6 from the transmission type Laue lens shown in FIG. In the case of an optical system using a Fresnel zone plate, since X-rays cross over at the focal point, spatial coherence is required to cause interference on the downstream X-ray lens 10. The SPring-8 synchrotron used in the experiment has a vertical spatial coherence of about 100 μm. Therefore, the optical system shown in FIGS. 1 to 3 was rearranged as seen from the top of the apparatus, and the X-ray width in the direction perpendicular to the paper surface (vertical direction) was limited to 100 μm by the entrance slit. Since the Fresnel zone plate used in the experiment has a diameter of about 1 mm, if the X-ray width in the direction perpendicular to the paper surface is limited to 100 μm by the entrance slit, sufficient N / A cannot be obtained and the horizontal direction (drawing) The condensing size became larger than the upper vertical direction. In this example, the vertical light collection size was about 1 μm. However, by using this example, the film thickness in the region of 50 μm × 1 μm on the sample surface can be measured.
Example 3
Finally, an embodiment of the present invention using wavefront division is shown in FIG. In this example, the transmission type Laue lens shown in the right of FIG. 6 was used as an X-ray condenser lens. The size of the Laue lens is about 1 mm square, and the focal length at a wavelength of 0.1 nm is 50 mm. X-rays using the undulator radiation source of the Synchrotron Radiation Research Center (SPring-8) at the High-intensity Optical Science Research Center have a vertical spatial coherence of about 100 μm, but a horizontal spatial coherence of only about 10 μm. Therefore, the wavefront division needs to be in the vertical direction. FIG. 4 corresponds to a view of the experimental arrangement viewed from the horizontal direction. The generated synchrotron radiation is monochromatized into X-rays with a wavelength of 0.1 nm by a monochromator, reflected by a flat plate higher-order light removal mirror, then limited to 100 μm vertically by the entrance slit 2 and 20 μm perpendicular to the paper surface, and an upstream X-ray lens 3 The upper 100 μm portion was irradiated with X-rays, and the focal position and condensing size of the first-order diffracted light 5 were measured with the knife edge 14. Next, the upstream X-ray lens 3 is lowered so that the incident X-ray 1 is irradiated only to the upper 50 μm above the upstream X-ray lens 3, and the reference wave 16 having a vertical width of 50 μm that does not pass through the upstream X-ray lens 3 is applied. Obtained. Next, the high-order diffraction light 6 was removed using the high-order diffraction removal slit 7, and the focal position was confirmed again using the knife edge 14. Sample 8 in which NiFe was formed to a thickness of about 100 nm as a thin film to be measured on a silicon thin plate was placed at the focal position. The first-order diffracted light 5 reflected by the sample became reflected X-rays 9. The two-dimensional detector 12 was moved to a position where the reflected X-ray 9 and the reference wave 16 overlapped, and interference fringes were measured. Even in the embodiment of the present invention, since the period of the interference fringes generated by the optical path difference between the reference wave and the object wave is very short, it cannot be detected by the two-dimensional detector 12 having a resolution of several μm. Since the obtained interference fringes reflect the phase difference due to the difference in the incident angle of the object wave reflected from the sample, the phase of the reference wave is changed by the phase plate 13, and the interference fringes are measured by the two-dimensional detector 12. Thus, the extreme value of the amplitude of the object wave and the coordinates of the node were obtained. In this example, by setting the incident angle to 1 ° ± 0.03 °, the X-ray irradiation area on the sample becomes 30μm × 20μm, and the extreme values are measured at θ = 0.988 °, 1.016 °, and the nodes are measured at 1.002 °, 1.030 °. It was done. By using Formulas 2 to 4 and Formula 4, it was possible to analyze that the film thickness of the measured sample was 102.3 nm. In this embodiment, there is a problem that the condensing angle of the first-order diffracted light 5 that becomes incident X-rays is as narrow as 0.06 °. However, when an X-ray laser such as XFEL is used as a light source, the upstream X-ray lens 3 is enlarged. The focusing angle range of the first-order diffracted light 5 can be expanded. Also, this embodiment is characterized in that the incident angle to the sample can be freely selected, unlike the previous embodiments. In the embodiment shown in FIGS. 1 to 3, the downstream X-ray lens 10 is required to superimpose the reference wave and the object wave, and therefore only one type of incident angle range can be selected when the X-ray wavelength is determined. In order to change the incident angle range, it is necessary to change the optical system significantly, such as changing the energy of incident X-rays or changing the combination of the focal lengths of the upstream X-ray lens 3 and the downstream X-ray lens 10. However, in this embodiment, even if the incident angle is changed, the interference fringes can be measured only by moving the two-dimensional detector 12 to a position where the reflected X-ray 9 and the reference wave 16 overlap. For this reason, it is possible to select the optimum incident angle for measuring the film thickness of the measurement sample when adjusting the sample.

  As described above, if this embodiment is used, it is possible to measure the X-ray phase reflectivity in a minute region by using the condensed X-ray and fixing the incident angle. It becomes possible to analyze the film thickness.

1: Incident X-ray 2: Incident slit 3: Upstream X-ray lens 4: 0th-order light 5: 1st-order diffracted light 6: High-order diffracted light 7: High-order diffraction removal slit 8: Sample 9: Reflected X-ray
10: Downstream X-ray lens
11: Interference X-ray
12: Two-dimensional detector
13: Phase plate
14: Knife edge
15: X-ray lens for magnification
16: Wedge-shaped phase plate
17: Reference wave

Claims (7)

Incident X-rays are incident on the upper half of the upstream X-ray lens, amplitude-divided into primary X-rays to be collected and zero-order light to be transmitted, and are specularly reflected by a sample placed at the focal position of the focused X-rays. the reflected X-ray successive reflection angle and the object wave, the so zero-order light interfere with the reference wave and the downstream side X-ray lens, microanalysis phase reflectometer for measuring interference fringes generated by interference in a two-dimensional detector a is, with a phase plate disposed in the optical path of the 0 order light, and modulating the phase of the reference wave, measures the phase of the reflected X-ray of the reflection angle to be continuous, the by difference in the incident angle A thin film laminate inspection method using a micro phase reflectometer that measures film thickness from the phase change of reflected X-rays.   2. The method for inspecting a thin film laminate according to claim 1, wherein the micro phase reflectometer has an X-ray lens for enlarging interference fringes between the two-dimensional detector and the downstream X-ray lens.   2. The method for inspecting a thin film stack according to claim 1, wherein the phase plate has a wedge shape.   The upstream X-ray lens and the downstream X-ray lens according to claim 1 are concentric Fresnel zone plates or transmissive Laue lenses, and the half-value width of the X-ray beam at the focal point of focusing is in the range of 1 nm to 10 μm. A method for inspecting a thin film laminate. Put upstream X-ray lens in half of the incident X-rays, incident on the upper half of the upstream side X-ray lens, the primary X-ray for focusing the object beam, has not passed through the said upstream side X-ray lens reference wave X-rays, and wavefront division, is specularly reflected by the sample placed at the focal position of the condensing X-ray, arranged a reflection X-ray reflection angle of successive, two-dimensional detector at a position overlapping the reference wave and, a small unit phase reflectometer for measuring the interference fringes, using a phase plate disposed in the optical path of the reference wave, modulates the phase of the reference wave, the reflected X-rays of the reflection angle successive Measure the phase,
Thin film stack inspection method using a micro-unit phase reflectometer to measure the film thickness from the phase change of the reflected X-ray due to difference in the incident angle.   6. The method for inspecting a thin film stack according to claim 5, wherein the phase plate has a wedge shape.   6. The thin film according to claim 5, wherein the upstream X-ray lens is a concentric Fresnel zone plate or a transmissive Laue lens, and the half-value width of the X-ray beam at the focal point of focusing is in the range of 1 nm to 10 μm. Laminate inspection method.

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