JPH0583122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an X-ray optical element evaluation apparatus for evaluating, for example, an oblique incidence mirror for X-rays, a multilayer mirror, and the like.

(Conventional technology) Recently, synchrotron radiation (SOR;
Synchrotron Orbital Radiation) and Plasma
X-ray sources such as X-rays have been developed and applied, for example, in the field of X-ray phosphorography. Along with this,
Optical elements have been developed to focus and image lines.
Such optical elements include oblique incidence mirrors,
There are multilayer mirrors, zone plates, etc.

Conventionally, evaluation of such an X-ray optical element is performed by making X-rays incident on the optical element to be evaluated and detecting the X-rays reflected by the optical element at this time. As the X-ray source at this time, an electron beam excitation type X-ray source and a SOR plasma X-ray source are used.

However, electron beam-excited X-rays have low X-ray brightness in the soft X-ray (wavelength 0.5 to 10 nm) region.
The problem is that it is difficult to detect. on the other hand,
Although SOR has the advantage of being about two orders of magnitude higher in brightness than the electron beam excitation type, on the other hand, the equipment is extremely large, so it has only been put into practical use in some areas. Finally, plasma X-ray sources are more suitable for evaluating X-ray optical elements than the other two because they have sufficient brightness and can be easily miniaturized. However, the brightness of plasma X-rays is
Compared to SOR, it is still insufficient, and
The X-rays emitted from the X-ray source and reaching the detector are only a few percent of the original X-rays because they disperse and escape along the way. For this reason, from the X-ray source to the detector,
It is necessary to arrange an optical system that has as little line dissipation as possible and is compact. however,
Currently, there is no X-ray optical element evaluation apparatus that fully satisfies these requirements. Furthermore, the conventional X-ray optical element evaluation apparatus has a drawback of low monochromatization resolution as a result of differences in the angle of incidence of incident X-rays.

(Problems to be Solved by the Invention) The present invention has been made in consideration of the above circumstances, and has high utilization efficiency of X-rays from an X-ray generator.
Another object of the present invention is to provide an X-ray optical element that can be miniaturized and has improved monochromatic resolution.

[Structure of the invention]

(Means and effects for solving the problem) An X-ray projection means that generates X-rays, and a first reflection that converts the X-rays from the X-ray projection means into parallel X-rays or focuses them on one point. a means for converting the X-rays from the first reflecting means into X-rays of an arbitrary wavelength;
It has a sample holding means that holds the sample so that the incident angle of the rays can be changed freely, and allows multiple types of evaluations to be performed efficiently and with high precision based on the reflected X-rays from the X-ray optical element. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an X-ray optical element evaluation apparatus according to a first embodiment. This device includes an X-ray generating section 2 that generates X-rays 1 for evaluation, and a first reflecting section 3 that converts the X-rays 1 generated in the X-ray generating section 2 into parallel light.
And X converted into parallel light by this first reflecting section 3
A second reflecting section 5 that monochromates the line 4 and a second reflecting section 5 that holds the sample W to be evaluated by X-rays and rotates in the direction of the arrow 6;
A sample holding unit 8 that receives the monochromatic X-rays 7 from the reflection unit 5, and an X-ray detection unit that receives the X-rays 9 reflected by the sample W and converts the received X-rays 9 into an electrical signal with a magnitude proportional to the incident amount. It consists of a section 10. Therefore, the X-ray generating section 2 includes a laser light source 12 that oscillates a laser light 11 such as a glass laser light, a lens system 13 that focuses the laser light 11 from this laser light source 12, and this lens system 13. It consists of a cylindrical target 14 into which the focused laser beam 11 is incident and generates the X-rays 1. The target 14 is made of, for example, aluminum Al, copper Cu, or the like, depending on the wavelength of the X-rays 1. On the other hand, the first reflecting section 3 includes a first slit 18 provided on the optical path of the X-rays 1 to block excess X-rays, and a generation point 19 provided on the light exit side of the first slit 18. a first mirror 20 having a paraboloid of rotation with a focal point at It is made up of. However, target 1
When the X-rays 1 emitted at 4 are incident on the first mirror 20, they are converted into parallel X-rays 4. Here, X
The oblique incidence angle θ of the line 1 on the first mirror 20 is 1 to
Set it extremely small again. As a result, X-ray 4
has the same wavelength as X-ray 1 except for the short wavelength side, and its reflection intensity is extremely high. Next, the second reflection section 5 is provided on the light output side of the second slit 21 and converts the X-rays 4 into monochromatic X-rays 7.
A mirror 22, a third slit 23 provided on the optical path of the X-rays 7 reflected by the second mirror 22 and allowing only necessary X-rays to pass through, and the second mirror 22 and the third slit 23. and a first goniometer 25 which is rotatably held in the direction of arrow 24 without changing their positional relationship. Then, the second mirror 22 is attached to the super-polished substrate 26.
Then, two types of substances, such as W and C, V and C, Au and C, Re and C, which do not diffuse into each other at the interface and have greatly different optical constants, are deposited on this substrate 26 in one layer. It consists of multilayer films 27 that are alternately deposited and stacked to have a thickness of 10 to several tens of angstroms. Such a multilayer film 27 has a so-called superlattice structure, and by changing its oblique incidence angle β,
Line 7 can be changed to a desired monochrome X-ray. The second mirror 22 is located at the center of rotation of the first goniometer 24. Next, the sample holding section 8
consists of a chuck (not shown) that removably holds the sample W, and a second goniometer 28 that supports the chuck rotatably in the direction of arrow 6. The sample W held in the chuck is
It is provided on the optical path of the X-ray 7 rotated by an angle 2β clockwise with respect to the optical path of the X-ray 4, and is set to be located at the center of rotation of the second goniometer 28. Furthermore, the X-ray detection unit 10 includes a detector 29 that is integrally attached to the second goniometer 28, and a fourth slit 30 that blocks excess X-rays 9 from entering the detector 29.
It consists of an evaluation/judgment section 31 that inputs electrical signals from the detector 29 and performs various calculations. The detector 29 and the fourth slit 30 are
If the oblique incident angle of the X-ray 7 to the sample W is γ, then
It is provided on the optical path of X-ray 9 rotated clockwise by 2γ from the optical path of line 7.

Next, the operation of the X-ray optical element evaluation apparatus having the above configuration will be described.

First, the chuck is made to hold the sample W, which is an X-ray optical element for evaluation. Next, the first goniometer 25 sets the oblique incident angle β of the X-rays 4 onto the second mirror 22 to a predetermined angle. Next, the laser light 11 from the laser light source 12 is focused on the generation point 19 of the target 14 via the lens system 13. Then, as the plasma at the generation point 19 is excited by the laser beam 11, the X-rays 1 pass through the first slit 18 and reach the first mirror 20 at an oblique incident angle θ (for example, 1 to 2 degrees). incident at As a result, the scattered X-rays 1 become parallel X-rays 4 and enter the second mirror 22 at an oblique incident angle β via the second slit 21. Then, this
Line 4 is detected by this second mirror 22 as a monochrome X with a wavelength determined by the oblique angle of incidence β.
It is converted to line 7. Next, this X-ray 7
After passing through the slit 23 and entering the sample W at an oblique incidence angle γ, it is reflected, becomes an X-ray 9, and enters the detector 29 via the fourth slit 30. Therefore, from the detector 29 into which the X-rays 9 are incident,
An electrical signal having a voltage proportional to the intensity of the incident X-rays 9 is output to the evaluation/judgment section 31, and the intensity of the X-rays 9 at this time is stored. Next, by operating the second goniometer 27, the oblique incident angle γ of the X-rays 7 on the sample W is sequentially changed, and the above-mentioned measurement process is repeated for each changed incident angle γ, and the The strength is stored in the evaluation determining section 31. Thereafter, the oblique incidence angle dependence of the X-ray reflectance of the sample W is plotted on a printer or CRT. Now, in the above description, the oblique incidence angle β is fixed and the oblique incidence angle γ is changed, or conversely, the oblique incidence angle γ is fixed and the oblique incidence angle β is changed to the first
By changing it using the goniometer 25, the dependence of the X-ray reflectance of the sample W on the X-ray wavelength can be measured.

As described above, in this first embodiment, since the first mirror 20 is a parabolic mirror of revolution, the subsequent X-rays 4, 7, and 9 can be collimated, and the reflection of the first mirror 20 The rate is over 90%, making it possible to use X-rays effectively. In particular, by collimating the X-rays with the first mirror 20, there is no need to consider the Rowland circle, and the distance L1 between the first mirror 20 and the second mirror 22, the distance L1 between the second mirror 22 and the sample W
Since the distance L2 between the sample W and the detector 29 and the distance L3 between the sample W and the detector 29 can be arbitrarily set, the apparatus can be downsized. In addition, since the oblique incident angles β of the X-rays 4 incident on the second mirror 22 are uniform, the resolution of monochrome conversion is improved and high-quality monochrome X-rays can be obtained. Furthermore, since the first mirror 20 has a high X-ray reflectance, sufficient evaluation can be performed even if the sensitivity of the detector 29 is low. In short, the X-ray optical element evaluation device of the first embodiment is a compact device that can perform multiple types of X-ray evaluations with high precision and high efficiency.

In addition, in the above embodiment, the X-ray generating section 2 is
A general X-ray tube may be used. Furthermore, the first mirror may be a multilayer mirror, and the second mirror may be a mirror having a paraboloid of revolution.

Next, an X-ray optical element evaluation apparatus according to a second embodiment of the present invention will be described.

FIG. 2 shows the X-ray optical element evaluation apparatus of this embodiment.
a first reflection section 43 that converts the X-rays 41 generated in the 1st reflection section 43 into parallel X-rays; and a second reflection section 43 that converts the parallel X-rays 44 reflected by the first reflection section 43 into monochromatic X-rays. part 45, a third reflection part 48 which makes the monochromatic X-rays 46 incident on this second reflection part 45 and focuses them on a focal point 47; A sample holder 51 holds the sample W at a position where the X-rays 49 are incident and rotates in the direction of an arrow 50, and an electric current whose magnitude is proportional to the incident amount is incident on the X-rays 52 reflected by the sample W. X to convert to signal
It is composed of a line detection section 53. However,
The X-ray generator 42 includes a laser light source 55 that oscillates a laser beam 54 such as a glass laser beam, a lens system 56 that focuses the laser beam 54 from the laser light source 55, and a lens system 56 that collects the laser beam 54. and a cylindrical target 57 into which the laser beam 54 is incident and generates the X-rays 41. The target 57 is made of aluminum Al, copper Cu, or the like, depending on the wavelength of the X-ray 41. On the other hand, the first reflecting section 43 includes a first slit 61 that is provided on the optical path of the X-rays 41 and blocks excess X-rays, and a first slit 61 that is provided on the light output side of the first switch 61 and includes a generation point 62 of the X-rays 41. a first mirror 63 having a paraboloid of rotation with a focal point at It is made up of. However,
The X-rays 41 emitted from the target 57 are
When incident on the mirror 63, it is converted into parallel X-rays 44. Here, the oblique incidence angle θ of the X-ray 41 on the first mirror 63 is set to be extremely small, 1 to 2 degrees. As a result, the X-rays 44, except for the short wavelength side,
It has the same wavelength as line 41, and its reflection intensity is extremely high. Next, the second reflecting section 45
A plane diffraction grating 65 provided on the light output side of the slit 64 and X reflected by this plane diffraction grating 65
A third slit 66 is provided on the optical path of the X-ray 46 and blocks unnecessary portions of the X-ray 46;
The first goniometer 68 holds the slit 66 and the flat diffraction grating 65 rotatably in the direction of the arrow 67 without changing their positional relationship. Therefore, the plane diffraction grating 65 is a plane sawtooth reflection grating, and since the incident angle at which diffraction occurs changes for each wavelength of X-rays having different wavelengths, it is possible to make X-rays monochromatic. becomes. Further, the plane diffraction grating 65 is positioned at the rotation center of the first goniometer 68. In other words, the plane diffraction grating 6
5 by the first goniometer 68, X-rays of arbitrary wavelengths can be selected. Further, the third reflecting section 48 has a third slit 6
A second mirror 69 is provided on the optical path of the X-rays 46 that have passed through the second mirror 69 and is provided with a paraboloid of revolution having the focal point 47, and the second mirror 69 is provided at the focal point 47 position and reflected by the second mirror 49, and a fourth slit 70 for blocking out excess material.
Next, the sample holder 51 includes a chuck (not shown) that removably holds the sample W, and a second goniometer 72 that supports the chuck so as to be rotatable in the direction of arrow 50. The sample W held in the chuck is transferred to the second goniometer 72.
It is set so that it is located at the center of rotation. Furthermore, the X-ray detection section 53 includes a second goniometer 72
A detector 73 is integrally attached to the second goniometer 72, and a slit 74 in FIG. Evaluation determination unit 75 that receives input and performs various calculations
It is made up of.

Next, the operation of the X-ray optical element evaluation apparatus of the second embodiment will be described.

First, the chuck is made to hold the sample W, which is an X-ray optical element for evaluation. Next, the first goniometer 68 sets the oblique incident angle β of the X-rays 44 onto the plane diffraction grating 65 to, for example, 3 to 4 degrees. Next, the laser light 54 from the laser light source 55 is focused on the generation point 62 of the target 57 via the lens system 56. Then, from this generation point 62, X-ray 4
1 is generated and enters the first mirror 63 through the first slit 61 at an oblique incidence angle θ (for example, 1 to 2 degrees). As a result, the scattered X-rays 41
becomes a parallel X-ray 44, which passes through the second slit 64 and enters the plane diffraction grating 65 at an oblique incidence angle β. The X-rays 44 are then converted into monochrome X-rays 46 having a wavelength determined by the oblique incidence angle β. Next, this X-ray 46 passes through the third slit 66 and hits the second mirror 6 at an oblique incidence angle λ.
9. Then, this incident X-ray 46
is reflected, becomes an X-ray 49, is focused on a focal point 47, and enters the sample W via a fourth slit 70 at an oblique incidence angle γ. The incident X-rays 49 are reflected by the sample W and the X-rays 52
The light then enters the detector 73 via the slit 74 in FIG. Therefore, the X-rays 52 that have entered the detector 73 are converted into electrical signals that have a voltage proportional to the intensity of the X-rays 52 that have entered the detector 73.
The intensity of the X-rays 52 at this time is stored. Next, the second goniometer 72 is operated to sequentially change the oblique incident angle γ of the X-ray 49 onto the sample W, and the above-mentioned measurement process is repeated for each changed incident angle γ to measure the intensity of the X-ray 52. The evaluation determination unit 75 stores the information. After that, X of sample W
Printer or
Plot on CRT. Now, the above description is
The oblique incidence angle β is fixed and the oblique incidence angle γ is changed, but conversely, when the oblique incidence angle γ is fixed,
By changing the oblique incidence angle β using the first goniometer 68, the dependence of the X-ray reflectance of the sample W on the X-ray wavelength can be measured. Furthermore, when the sample W is a superlattice multilayer mirror, the lattice constant and surface roughness of the multilayer film can be estimated.

As described above, in this second embodiment, since the first mirror 63 is a parabolic mirror of revolution,
The lines 44 can be made parallel X-rays, and dissipation of the X-rays can be prevented, so that the X-rays can be used effectively. Therefore, there is no need to consider the Rowland circle, and the distance L' between the first mirror 63 and the plane diffraction grating 65 and the distance L'' between the plane diffraction grating 65 and the second mirror 69 can be arbitrarily set. Since the settings can be made, it is possible to downsize the apparatus.Also, multiple types of X-ray evaluations can be performed with high precision and high efficiency.

Note that in the second embodiment, the X-ray generating section 42 may be a general X-ray tube.

Next, an X-ray optical element evaluation apparatus according to a third embodiment of the present invention will be described.

FIG. 3 shows an X-ray optical element evaluation apparatus according to this embodiment.
a first reflecting section 83 that condenses the X-rays 80 generated at the focal point 82; and a second reflecting section 85 that makes the X-rays 84 reflected at the first reflecting section 83 incident and monochromatic.
and a sample holding section 88 that holds the sample W and rotates in the direction of arrow 104 and causes the monochromatic X-rays 87 to be incident on the sample W at the second reflection section 85, and the X-rays reflected by the sample W. The X-ray detecting section 90 receives the incident X-ray 89 and converts it into an electrical signal having a magnitude proportional to the incident amount. Therefore, the X-ray generating section 81
For example, a laser light source 92 that oscillates laser light 91 such as a glass laser light, a lens system 93 that focuses the laser light 91 from this laser light source 92, and the laser light 91 focused by this lens system 93 is incident. The target 94 has a cylindrical shape that generates the X-rays 80, and is made of a material such as Al or Cu. On the other hand, the first reflecting section 83
is a spheroidal mirror having two focal points 82 and 98, one focal point 98 is located at the target 94.
The laser beam 91 is focused at the following position. Further, the other focal point 82 is a second reflecting portion 85
is located behind. Furthermore, the second reflecting section 85
includes a multilayer mirror 99 that makes the X-rays 84 from the first reflection section 83 incident monochromatic, and a first goniometer that is rotatably provided in the direction of arrow 100 and holds the multilayer mirror 99 at the center of rotation. It consists of 101. Therefore, the multilayer mirror 99 consists of a super-polished substrate 102 and a layer of materials such as W and C, V and C, and Au that are deposited on the substrate 102 and do not diffuse into each other at the interface and have greatly different optical constants. It consists of a multilayer film 103 in which two types of substances, such as C, Re, and C, are deposited and laminated alternately so that each layer has a thickness of 10 to several tens of angstroms. Such a multilayer film 103 has a so-called superlattice structure, and its oblique incidence angle β
is provided to convert the X-rays 84 into desired monochrome X-rays 87 by changing the X-rays 84 through the first goniometer 101. On the other hand, the sample holding section 88 includes a chuck (not shown) that detachably holds the sample W, and a second goniometer 105 that is rotatably provided in the direction of the arrow 104 and holds the chuck at the center of rotation. It's summery. Then,
X-ray 8 by adjusting the rotation of the second goniometer 105
The oblique incidence angle γ of No. 7 onto the sample W can be changed. Furthermore, the X-ray detection section 90
, a detector 106 that is integrally attached to the second goniometer 105 and receives the X-rays 89 reflected from the sample W;
slit 10 attached to remove excess X-rays
7, and an evaluation/judgment section 108 that inputs electrical signals from the detector 106 and performs various calculations.

Next, the operation of the X-ray optical element evaluation apparatus of the third embodiment will be described.

First, the chuck is made to hold the sample W, which is an X-ray optical element for evaluation. Next, the first goniometer 101 sets the oblique incident angle β of the X-rays 84 onto the multilayer mirror 99 to a predetermined angle. Next, laser light 91 from a laser light source 92 is focused onto a target 94 via a lens system 93. Then,
From the target 94, the X-rays 80 are transmitted to the first reflecting section 8.
3. Then, the X-rays 84 reflected by the first reflecting section 83 are reflected in a direction to be condensed at the focal point 82, but are incident on a multilayer mirror 99 disposed in the middle at an oblique incidence angle β. Then, a monochrome X having a wavelength determined by this oblique incidence angle β
A line 87 is incident on the sample W at an oblique incidence angle γ. Further, the X-rays 89 reflected from the sample W enter the detector 106 via the slit 107, and an electric signal having a voltage corresponding to the incident amount is output to the evaluation/judgment section 108. The intensity of the X-rays 89 is stored. In addition, in FIG. 3, when the distance between the second reflection section 85 and the focal point 82 is La, the distance between the second reflection section 85 and the sample W is Lb, and the distance between the sample W and the detector 106 is Lc, La=Lb.
There is a relationship of +Lc. Next, the second goniometer 105 is operated to sequentially change the oblique incident angle γ of the X-ray 87 onto the sample W, and the measurement process described above is repeated for each changed incident angle γ.
9 is stored in the evaluation determining unit 108. Thereafter, the oblique incidence angle dependence of the X-ray reflectance of the sample W is plotted on a printer or CRT.

Now, the above description fixes the oblique incidence angle β,
This is obtained by changing the oblique incidence angle γ, but conversely,
The oblique incident angle γ is fixed, and the first goniometer 101
If the oblique incidence angle β is changed by
The dependence of linear reflectance on X-ray wavelength can be measured. Furthermore, when the sample W is a superlattice multilayer mirror, it is possible to estimate the special constant and surface roughness of the multilayer film.

As described above, in this third embodiment, since the first reflecting section 83, which is a spheroidal mirror, focuses the X-rays 80 on the focal point, the dissipation of the X-rays is almost eliminated. can be used effectively, and multiple types of X-ray evaluations can be performed with high accuracy and efficiency. In addition, the optical system can be assembled without considering the Rowland circle, so
It is possible to downsize the device.

Note that in the third embodiment, the X-ray generating section 81 may be a normal X-ray tube.

Furthermore, in the first to third embodiments,
If the plasma X-rays generated in the X-ray generators 2, 42, and 81 are configured to be extracted in other directions, they can also be used for other purposes.

〔Effect of the invention〕

The X-ray optical element evaluation device of the present invention can prevent X-ray dissipation without considering the Rowland circle, and can evaluate multiple types of X-ray reflectance, such as X-ray wavelength dependence and oblique incident angle dependence. X-ray evaluation can be performed with high efficiency and accuracy. Therefore, by applying the present invention, it is possible to make a significant contribution to the development and manufacture of X-ray optical elements.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the first embodiment of the present invention;
The figure is an explanatory diagram of the second embodiment of the invention, and FIG. 3 is an explanatory diagram of the third embodiment of the invention. 2, 42, 81... X-ray generating section (X-ray projection means), 3, 43, 83... First reflecting section (first reflecting means), 5, 45, 85... Second reflecting section, 8 ，
51, 88... Sample holding section, 10, 53, 90...
...X-ray detection section.

Claims (1)

[Scope of Claims] 1. In an X-ray optical element evaluation device that projects X-rays onto an X-ray optical element and evaluates the X-ray optical element based on reflected X-rays that are reflected at this time, the X-ray is projected. an X-ray projection means; a first reflection means having a paraboloid of rotation that receives the X-rays projected from the X-ray projection means and converts them into parallel X-rays;
It has a multilayer mirror that converts parallel X-rays from the reflecting means into X-rays of a specific wavelength by changing the angle of incidence of the parallel X-rays on the multilayer mirror. a second reflecting means for selectively adjusting the wavelength of the X-ray; and a sample holding means for holding the X-ray optical element so as to freely adjust the incident angle of the X-ray of a specific wavelength from the second reflecting means; X-ray optical element evaluation characterized by comprising an X-ray detection means for injecting reflected X-rays from the X-ray optical element held by the sample holding means and converting the reflected X-rays into an electric signal indicating the incident intensity. Device. 2. In an X-ray optical element evaluation device that projects X-rays onto an X-ray optical element and evaluates the X-ray optical element based on the reflected X-rays reflected at this time, an X-ray projection means that projects the X-rays; a first reflecting means having a paraboloid of rotation that receives the X-rays projected from the X-ray projecting means and converts them into parallel X-rays;
It has a plane diffraction grating that converts parallel X-rays from the reflecting means into X-rays of a specific wavelength by changing the angle of incidence of the parallel X-rays on the plane diffraction grating. a second reflecting means for selectively adjusting the wavelength of the X-ray; and a sample holding means for holding the X-ray optical element so as to freely adjust the incident angle of the X-ray of a specific wavelength from the second reflecting means; X-ray optical element evaluation characterized by comprising an X-ray detection means for injecting reflected X-rays from the X-ray optical element held by the sample holding means and converting the reflected X-rays into an electric signal indicating the incident intensity. Device. 3. In an X-ray optical element evaluation device that projects X-rays onto an X-ray optical element and evaluates the X-ray optical element based on the reflected X-rays reflected at this time, an X-ray projection means that projects the X-rays; a first reflecting means having an ellipsoid of revolution that allows the X-rays projected from the X-ray projecting means to enter and condense them at a focal position;
It has a multilayer mirror that converts the focused X-rays from the reflecting means into X-rays of a specific wavelength by changing the angle of incidence of the focused X-rays on the multilayer mirror. a second reflecting means for selectively adjusting the wavelength of the ray; a sample holding means for holding the X-ray optical element so as to freely adjust the incident angle of the X-ray of a specific wavelength from the second reflecting means; An X-ray optical element evaluation device comprising an X-ray detection means for injecting reflected X-rays from an X-ray optical element held by a sample holding means and converting the reflected X-rays into an electric signal indicating the incident intensity. .