JP2002286658A - Apparatus and method for measurement of x-ray reflectance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently measure an X-ray reflectance over a wide region on the surface of a sample. SOLUTION: In the X-ray reflectance measuring apparatus, line focus X-rays 2a radiated from an X-ray source 10 are made monochromatic via a monochromator 20 so as to be shone at the surface 3a of the sample, and X-rays 2c reflected by the surface 3a of the sample 3 are detected. An asymmetric reflecting member 30 which reflects X-rays 2b at an asymmetric angle with reference to the angle of incidence of the X-rays 2a is arranged on an X-ray optical path between the monochromator 30 and the sample 3. The angle of the surface 31 of the member 30 to a crystal grating face 32 is set in such a way that the angle of reflection of the X-rays 2b with reference to the surface 31 of the member 30 becomes larger than the angle of incidence of the X-rays 2a. By the member 30, the X-rays 2a which are expanded in the longitudinal direction are taken out so as to be shone at the surface 3a of the sample 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention non-destructively analyzes the physical properties of a sample by irradiating the surface of the sample with an X-ray at a low angle and detecting a change in the intensity of the X-ray reflected from the surface of the sample. -Ray reflectivity measuring apparatus and method therefor.

[0002]

2. Description of the Related Art As a measuring method using X-rays, there is an X-ray reflectivity measuring method for evaluating physical properties of a sample by utilizing a specular reflection phenomenon of X-rays. This X-ray reflectivity measuring method includes, for example,
It is suitable for evaluating the thickness, density, surface roughness of the thin film, roughness of the interface between the thin film and the substrate material, and the like, of a single-layer or multilayer thin film formed on the surface of the substrate material. The principle of this X-ray reflectivity measuring method is as follows (FIGS. 8 to 1).
1).

[0003] In FIG. 8, when an X-ray is irradiated at a low angle θ of the surface of a substance 201 having a flat surface, the substance 20 is irradiated.
Below the critical angle peculiar to 1, X-rays are totally reflected. This critical angle is very small, for example, for X-rays of CuKα,
0.22 ° for Si or glass plate, 0.42 ° for Ni,
For Au, it is 0.57 °.

This critical angle changes depending on the electron density of the substance. As the X-ray irradiation angle becomes larger than this critical angle, the X-rays gradually penetrate deeper into the material. In a substance having an ideal plane, as shown by a curve A in FIG. 9, when the X-ray irradiation angle θ is equal to or larger than the critical angle θc, the X-ray reflectance sharply decreases in proportion to θ ^−4. . In addition, if the surface of the material is rough, the degree of the reduction will be even greater, as indicated by the dashed line B. On the vertical axis of the figure, I ₀ is the irradiation X-ray intensity and I is the reflected X-ray intensity.

As shown in FIG. 10, using such a substance as a substrate 201, another substance having a different electron density is uniformly laminated on the substrate 201 to form a thin film 202. When the X-ray is irradiated at a low angle, the substrate 201 and the thin film 20 are irradiated.
2 and the X reflected at the surface of the thin film 202.
The lines are stronger or weaker each other. As a result, as shown in FIG. 11, a vibration pattern C due to X-ray interference appears on the reflectance curve.

From the cycle of the vibration pattern C, the thin film 20
2 can be determined, and surface and interface information can be obtained from the angular dependence of the amplitude of the vibration pattern. further,
By examining both the period and the amplitude of the vibration pattern together, the density of the thin film 202 can be obtained. In normal X-ray reflectivity measurement, the X-ray irradiation angle θ on the sample surface
Is changed in the range of 0 ° to 5 °, and in the range of 0 ° to 10 ° in the case of a wide range, and the intensity of the X-ray reflected on the sample surface is irradiated.
Detection is performed in the direction of 2θ with respect to the optical path of the line.

FIG. 12 is a schematic plan view showing the structure of a conventional X-ray reflectivity measuring device. In the X-ray reflectance measuring apparatus 300 shown in the figure, an X-ray 302 emitted from a point-focused X-ray source 301 using a Cu target is
A (111) crystal monochromator 303 converts the light into a single color parallel X-ray of only CuKα1 and irradiates the sample surface 304 at a low angle. Then, the X-ray 307 reflected from the sample surface 304 is detected by a detector 305 using a NaI scintillation counter. The scanning of the incident angle and the reflection angle of the X-ray with respect to the sample surface 304 is performed with a minimum scanning angle width of 0.0.
The measurement is performed using a goniometer 306 of 01 °.

An X-ray reflectance measuring apparatus disclosed in Japanese Patent Application Laid-Open No. 7-31163 discloses an X-ray irradiation unit including a point-focused X-ray source and a crystal monochromator.
The arm is supported by the arm, the detector unit including the detector is supported by the second arm, and each arm is independently synchronized by a tangent bar system using an elevating device while the sample is supported horizontally. Scan the angle to the surface,
The scanning of the X-ray irradiation angle and the scanning of the detector with respect to the optical path of the irradiation X-ray are performed.

[0009]

In the above-mentioned conventional X-ray reflectivity measuring apparatus, the length dimension of the X-ray taken out from the point-focused X-ray source is small, and only a limited part of the surface of the sample is measured. A method of irradiating X-rays and measuring the X-ray reflectance of the portion has been adopted. Therefore, in order to perform area mapping for analyzing changes in various characteristics over the entire area of the sample surface, the measurement area is changed and a large number of X-rays are performed.
It is necessary to perform a linear reflectance measurement, which is complicated.

To cope with this problem, an X-ray reflectivity measuring apparatus having a configuration in which a measurable area with respect to a sample surface is enlarged by using an X-ray source for generating line-focused X-rays is also known. FIG. 13 is a diagram showing a conventional example of this type of X-ray reflectivity measuring apparatus. X-ray reflectometer 400 shown in FIG.
Is disclosed in Japanese Patent Application Laid-Open No. 5-322804, in which an X-ray 402 is generated using a line-focused X-ray source 401 having a longitudinal dimension of 30 mm, and after the X-ray 402 is made monochromatic, a sample is obtained. As a configuration for performing X-ray reflectance measurement by irradiating the surface 403 at a low angle, the irradiation area of the X-ray 402 on the sample surface 403 is expanded.

However, depending on the object to be measured, there is a large type which requires a large number of area mappings even if the above-mentioned conventional X-ray reflectivity measuring apparatus 400 is used. For example,
For semiconductor wafers, especially silicon wafers, LSI
The diameter has been increasing from the viewpoint of improving the cost performance of manufacturing. In recent years, the diameter has been increased from 200 mm to 300 mm.
Wafers are being used. For this reason, in the X-ray reflectivity measurement (area mapping) of the semiconductor wafer, the measurement region on the film surface tends to be enlarged.

The present invention has been made in view of such circumstances, and has as its object to further expand the measurement area that can be performed at one time and to realize efficient X-ray reflectance measurement over a wide range of the sample surface. And

[0013]

In order to achieve the above object, according to the first aspect of the present invention, X-rays of line focus are converted to monochromatic light through a monochromator to irradiate the sample surface, and are reflected on the sample surface. In an X-ray reflectometer for detecting X-rays, an asymmetrical reflection member that reflects X-rays at an angle that is asymmetrical with respect to the incident angle of X-rays is disposed on an X-ray optical path between the monochromator and the sample, X-rays are incident on the asymmetrical reflection member at an arbitrary angle, so that the X-rays enlarged in the longitudinal direction of the line focus are taken out from the asymmetrical reflection member and irradiated on the sample surface.

According to a second aspect of the present invention, there is provided a line-focused X-ray source, a monochromator for monochromaticizing X-rays emitted from the X-ray source, and an X-ray emitted from the monochromator in a longitudinal direction of the line focus. An asymmetrical reflecting member that expands, a goniometer that holds the sample, and has at least a θ axis that adjusts the incident angle of X-rays incident on the sample surface, and an X-ray detector that detects X-rays reflected on the sample surface, It is characterized by having.

According to these inventions, since the longitudinal direction of the X-rays emitted from the X-ray source is irradiated to the sample surface by the asymmetric reflection member, the X-ray irradiation area on the sample surface is expanded. The area on the sample surface which can be measured at one time can be enlarged. Therefore, for example, even when measurement is performed over a wide area on the wafer surface as in the measurement of X-ray reflectance of a semiconductor wafer, the number of measurements can be reduced, and X-ray reflectance measurement can be performed efficiently. be able to.

Further, the apparatus may be provided with X-ray irradiation area changing means for changing the X-ray irradiation area on the sample surface by moving the sample on a plane including the θ axis of the goniometer and along the sample surface. In the third aspect, the X-ray irradiation position on the sample surface can be arbitrarily moved and adjusted.

Further, the X-ray detecting section is equipped with a two-dimensional position sensitive type X-ray recording means, and is rotated by 2θ about the θ axis of the goniometer in synchronization with the scanning of the incident angle of the X-ray on the sample surface. If the X-ray recording means is moved on the X-ray detecting section (claim 4), the recording density of the reflected X-rays in the X-ray recording means can be freely increased to improve the reading accuracy (resolution). It can be improved.

According to a fifth aspect of the present invention, there is provided a method for measuring an X-ray reflectivity, wherein the line-focused X-ray is made monochromatic through a monochromator to irradiate the sample surface and detect the X-ray reflected from the sample surface. In the X-ray reflectance measurement method, monochromatic X-rays are made incident on an asymmetrical reflection member that reflects the X-rays at an angle that is asymmetrical with respect to the incident angle of the X-rays, thereby expanding the X-rays in the longitudinal direction of the line focus. Is taken out from the asymmetric reflection member and irradiated on the sample surface.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. << First Embodiment >> FIG. 1 is a perspective view showing an outline of an X-ray reflectometer according to a first embodiment of the present invention, and FIG. 2 is a front view showing the same X-ray reflectometer.

As shown in these figures, the X-ray reflectivity measuring apparatus 1 comprises an X-ray source 10, a monochromator 20, an asymmetric reflecting member 30, a goniometer 40, a sample mounting device 50,
A line detection unit 60 and a control system 70 are included. In addition,
In this specification, the long side of the line focus is defined as the longitudinal direction of the X-ray, and the short side is defined as the width direction of the X-ray.

The X-ray source 10 uses a rotating X-ray tube of a Cu target for a cathode as a line focus.
The line source 10 emits line-focused X-rays 2.
The focal size of the X-ray source 10 is, for example, 0.1 mm in width and 10 mm in length. In this case, the length 10
The X-ray 2 with a line focus of mm is emitted.

The cathode side of the X-ray source 10 has LaB ₆
The intensity uniformity of the X-rays 2 emitted from the X-ray source 10 is ensured by using a non-winding type cathode using the above method. On the cathode side, a wound cathode using a W filament may be used. In this case, the X-ray tube is caused to slightly reciprocate in the line direction, and the X-ray emitted from the X-ray source 10 is emitted. It is preferable to make the line 2 uniform. The X-rays 2 emitted from the X-ray source 10 are incident on a monochromator 20 made of a flat plate single crystal through a divergence limiting slit 11 while restricting the divergence in the longitudinal direction and the width direction.

The monochromator 20 has a function of monochromaticizing the X-rays 2 incident from the X-ray source 10. That is, when the X-rays 2 are incident on the monochromator 20, the characteristic X-rays 2a corresponding to the material constituting the anti-cathode of the X-ray source 10 are obtained.
(For example, if the substance is Cu, CuKα1) is extracted.

The monochromator 20 has a surface (11
1) Cut out parallel to the lattice plane,
It is made of chemical polished FZ method silicon single crystal.
It has a function of extracting monochromatic X-rays 2a of only CuKα1 by symmetrically reflecting at 4.2 °. This monochromatic X
The line 2a is incident on the asymmetric reflection member 30 through the divergence limiting slit 21 while restricting the divergence in the longitudinal direction and the width direction. The divergence limiting slit 21 is set, for example, at a distance of about 300 mm from the X-ray source 10, the slit interval in the longitudinal direction is 10 mm, which is the same as the length of the X-ray 2 a, and the slit interval in the width direction is 0.2 mm.

The asymmetrical reflection member 30 is a monochromator 2
It has a function of extracting the X-ray 2a incident from 0 in the longitudinal direction and extracting it. That is, as shown in FIG. 3, the asymmetric reflection member 30 has a lattice plane 32
Is formed at an angle β, and when the X-ray 2a is incident on the surface 31 of the asymmetrical reflection member 30 at an angle α,
Bragg reflection of Bragg angle (α + β) occurs on the crystal lattice plane 32, and the surface 31 of the asymmetric reflection member 30
The light is reflected at an angle (α + 2β), that is, reflected asymmetrically.

In the present embodiment, the asymmetric reflection member 3
The asymmetrical reflection member 30 is formed such that the reflection angle of the X-rays 2b with respect to the surface 31 of the X-ray 2 is larger than the incident angle of the X-rays 2a. The X-ray 2b can be extracted by increasing the length B of the line 2b.

In the present embodiment, the FZ method silicon single crystal ingot grown in the [001] direction is moved one axis from the growth axis.
Cut at an angle of 0.6 °, length 300mm, width 30m
m, a silicon single crystal plate having a thickness of about 10 mm is used as the asymmetric reflection member 30, and the entire surface of the crystal plate is
It is mechanically and chemically polished without distortion.

The asymmetric reflecting member 30 is mounted on a driving device 35 including an incident angle adjusting mechanism 33 and a crystal tilt / position adjusting mechanism 34. FIG. 4 is a perspective view showing a driving direction of the asymmetric reflection member by this driving device. The incident angle adjusting mechanism 33 drives the asymmetrical reflection member 30 to rotate about the rotation axis O in the direction of the arrow a to rotate the asymmetrical reflection member 30.
Has the function of adjusting the incident angle of the X-rays 2a with respect to the surface. By adjusting the incident angle of the X-rays 2a by the incident angle adjusting mechanism 33, it is possible to set an appropriate incident angle for extracting the X-rays 2b with good parallelism and expanded in the longitudinal direction from the asymmetrical reflection member 30. Becomes

The crystal tilt / position adjusting mechanism 34 adjusts the tilt angle of the asymmetric reflection member 30, the in-plane angle adjustment means for rotating the asymmetric reflection member 30 in the plane, and the incident X-ray. It has each function as an X-ray irradiation position adjusting means for performing parallel movement along the optical axis of 2a. That is, the crystal tilt / position adjustment mechanism 3
By rotating the asymmetric reflection member 30 in the direction of the arrow b in the drawing, the tilt angle of the member 30 can be adjusted. By adjusting the tilt angle, the sample surface 3a is adjusted.
Can roughly adjust the irradiation position of X-rays 2b with respect to.

The irradiation position of the X-ray 2b on the sample surface 3a can be finely adjusted by rotating the asymmetric reflection member 30 in the plane of the arrow c in the drawing by the crystal tilt / position adjustment mechanism 34. . By this rotation operation, if the longitudinal direction of the X-rays 2b irradiating the sample surface 3a is set parallel to the θ-2θ rotation axis of the goniometer 40 described later,
It becomes parallel to the longitudinal direction of the X-ray irradiation area on the sample surface 3a. As a result, X-ray reflectivity can be measured under almost the same conditions in the entire irradiation area of the X-rays 2b.

Further, the asymmetric reflecting member 30 is moved by the crystal tilt / position adjusting mechanism 34 in the direction indicated by the arrow d in FIG.
The X-ray 2b taken out from the asymmetrical reflection member 30 can be translated in the longitudinal direction by moving in parallel in the optical axis direction (a). This makes it possible to arbitrarily move and adjust the X-ray irradiation position in the θ-axis direction on the sample surface 3a.

The X-rays 2b which are enlarged and taken out in the longitudinal direction by the asymmetrical reflection member 30 restrict the divergence in the longitudinal direction and the width direction through the entrance slit 36 to restrict the sample surface 3
The light is applied to an elongated measurement area 4 parallel to the θ-axis at the center of “a”. The incident slit 36 is mounted on a driving device 37, and the driving device 37 uses the driving device 37 to change the slit interval in the longitudinal direction and the slit interval in the width direction according to the length of the X-ray 2b extracted by the asymmetrical reflection member 30. And the horizontality of the entrance slit 36 and the position adjustment in the width direction can be performed.

The goniometer 40 includes a sample angle scanning mechanism 4
1 and a detector arm angle scanning mechanism 42,
These scanning mechanisms 41 and 42 have the same rotation axis (hereinafter, θ-
(Referred to as 2θ rotation axis). Further, the goniometer 40 is provided with a width direction position adjustment mechanism 43, and the mechanism 43 can adjust the position of the goniometer 40 in the width direction.

A sample mounting device 50 holding a sample 3 to be subjected to X-ray reflectance measurement is attached to the sample angle scanning mechanism 41.
By rotating about the 2θ rotation axis (θ rotation), the incident angle θ of the X-rays 2b incident from the asymmetric reflection member 30 with respect to the sample surface 3a can be adjusted.

The sample mounting device 50 includes a sample support 5
The sample 3 is held horizontally by the sample support 51. The sample support table 51 includes an in-plane rotation mechanism 5.
2 is provided, and the in-plane rotation of the sample 3 is enabled by the mechanism 52.

The sample support table 51 and the in-plane rotation mechanism 52 are mounted on a stage 53, and the stage 53 includes a horizontal drive mechanism (X-ray irradiation position adjusting means) 5.
4 and a width direction driving mechanism 55. That is,
The horizontal driving mechanism 54 allows the stage 53 to move in parallel in the illustrated Y direction along the optical axis of the X-ray 2b while the sample 3 is held horizontally. Therefore, the irradiation position of the X-ray 2b on the sample surface 3a can be changed by the horizontal driving mechanism 54.

The stage 53 can be moved in the width direction by the width direction driving mechanism 55, and the position of the sample 3 in the width direction can be finely adjusted. The stage 53
In the width direction, a sample having a standard thickness is
It is set in advance so that when held at 1, the θ-2θ rotation axis of the goniometer 40 is placed on the surface 3a of the sample 3.

A detector arm 44 is mounted on the detector arm angle scanning mechanism 42, and an X-ray detector 60 is mounted on the detector arm 44. With this mechanism 42, the X-ray detection unit 60 can be rotated (2θ rotation) in synchronization with the θ rotation of the sample 3.

The X-ray detector 60 is an X-ray detector 61 for detecting the intensity of the X-ray 2c reflected from the sample surface 3a.
And a two-dimensional position-sensitive detector (X-ray recording means) 63 for recording the intensity of the X-rays 2c. As the X-ray detector 61, a small scintillation counter is used to restrict the divergence of the X-rays 2c reflected from the sample surface 3a in the longitudinal direction and the width direction via a slit (not shown). The intensity of the X-rays 2c is detected. Note that the length of the X-ray 2c incident on the X-ray detector 61 is limited to about 5 mm by a slit.

The X-ray detector 61 is mounted on a driving device 62, and the driving device 62 can move the X-ray detector 61 in the longitudinal direction. That is, the X-ray detector 6
When detecting the intensity of the X-rays 2c reflected from the sample surface 3a by 1, the driving device 62 sequentially moves the X-ray detectors 61 in the longitudinal direction according to the length of the X-rays 2c and reflects the X-rays. The intensity over the entire length of the X-ray 2c is detected.

In this embodiment, an imaging plate is used as the two-dimensional position sensitive detector 63, and the X-ray reflected from the sample surface 3a is reflected on the imaging plate.
Record the intensity of line 2c. The two-dimensional position-sensitive detector 63 has a length capable of recording the incident X-ray 2c over the entire length. Further, the two-dimensional position-sensitive detector 63 is detachably mounted on the driving device 64,
The driving device 64 can move in the Z direction in the drawing along the width direction. Thus, for example, when the sample 3 is translated in the Y direction by the horizontal driving mechanism 54 of the sample mounting device 50 to change the irradiation area of the X-ray 2b on the sample surface 3a, the driving device 64 The two-dimensional position-sensitive detector 63 is moved in the Z direction, and the X-rays 2 reflected on the sample surface 3a to another region on the imaging plate.
The intensity of c can be recorded.

The X-ray detecting section 60 has a detecting slit 65.
The detection slit 65 is provided on the upstream side of the optical path of the X-ray 2c with respect to the two-dimensional position sensitive detector 63. The X-rays 2c reflected from the sample surface 3a are incident on the X-ray detector 60 via the detection slit 65 while restricting divergence in the longitudinal direction and the width direction.

The control system 70 of the X-ray reflectivity measuring device 1 comprises a control device 71, a storage device 72, and a display device 73. The control device 71 is an X-ray reflectance measuring device 1
Has a function as a central control unit (CPU) for controlling each unit. Further, the storage device 72 has a function of recording the intensity data of the X-ray 2c detected by the X-ray detector 61. Further, the display device 73 has a function of displaying an X-ray reflectance curve created based on the intensity data of the X-rays 2c.

[Position Adjustment of Each Component] Next, the X
A method of adjusting the position of each component in the linear reflectance measuring device 1 will be described with reference to FIGS. First, the sample 3 is held on the sample support 51 of the sample mounting device 50.
When the thickness of the sample 3 is different from the standard sample thickness, the control device 71 outputs an operation command to the width direction driving mechanism 55 of the sample mounting device 50 via the goniometer 40 to move the stage 53. The rotation axis of the goniometer 40 is set to be on the sample surface 3a.

Next, the control device 71 sets the asymmetric reflection member 3
0, and outputs an operation command to the driving device 35 to operate the driving device 35.
The tilt angle adjustment, the in-plane angle adjustment, and the position adjustment along the optical axis of the X-ray 2a of the asymmetric reflection member 30 are performed.
1 is adjusted with respect to the X-ray 2a incident from the monochromator 20.

In this embodiment, the monochromator 2
The incident angle of the X-rays 2a monochromated by 0 is set to 1.6 ° with respect to the surface 31 of the asymmetrical reflection member 30 so that when the X-rays 2a enter the surface 31, asymmetrical 333 reflection occurs. Keep it. By this operation, the length of about 3
An X-ray 2b enlarged to 00 mm is obtained.
Even when measuring the X-ray reflectivity of an oxide film or a metal thin film formed on the surface of a large silicon wafer of 00 mm, the measurement can be performed all at once in the longitudinal direction of the wafer surface, that is, in the X direction shown in the figure.

Subsequently, the controller 71 controls the entrance slit 36
An operation command is output to the driving device 37 to ensure the horizontality of the entrance slit 36 and to adjust the width direction, and to set the slit interval in the longitudinal direction to 30 mm having the same length as the X-ray 2b.
0 mm and the slit interval in the width direction are set to 1 mm or less.

Further, the controller 71 controls the goniometer 40
An operation command is output to the width direction position adjusting mechanism 43, and the mechanism 43 is operated to irradiate the line focus X-rays 2b in parallel to the entire sample surface 3a. The position of the goniometer 40 in the width direction is finely adjusted so as to be halved in the width direction. Then, the control device 71 outputs an operation command to the horizontal driving mechanism 54 of the sample mounting device 50, and the mechanism 3 translates the sample 3 in the Y direction, thereby irradiating the X-ray 2b with the irradiation position of the X-ray 2b and the measurement area of the sample surface 3a. The position of the measurement area 4a is adjusted so that the measurement area 4a is irradiated with the X-ray 2b extracted by the asymmetric reflection member 30.

Thereafter, the control device 71 sets the goniometer 40
An operation command is output to the sample angle scanning mechanism 41 and the detector arm angle scanning mechanism 42 to operate these mechanisms 41 and 42 to rotate θ of the sample 3 and 2θ of the X-ray detector 60.
Rotation is performed to set the irradiation angle θ of the X-ray 2b to the sample surface 3a and to set the X-ray 2b
The line detector 60 is moved. At this stage, the two-dimensional position-sensitive detector 63 is not mounted, and the X-rays 2c reflected from the sample surface 3a can be detected by the X-ray detector 61.

[Measurement of X-ray reflectivity] Next, a method of measuring X-ray reflectivity using the above-described X-ray reflectometer 1 will be described.
This will be described mainly with reference to FIGS. A line-focused X-ray 2 having a length of 10 mm is emitted from the X-ray source 10, the X-ray 2 is monochromatized by a monochromator 20, and then expanded to 300 mm in length by an asymmetrical reflection member 30. Irradiate the measurement area 4a. Then, a predetermined range (for example, 0 to
10 °), the sample 3 is rotated by θ, and the X-ray detector 6
By rotating 0 by 2θ, the intensity of the X-ray 2c reflected from the sample surface 3a is detected by the X-ray detector 61.

The control device 71 performs a predetermined data analysis based on the intensity data of the X-rays 2c detected by the X-ray detector 61, and stores the analysis result in the storage device 72 and the display device 73. indicate. The sample surface 3a
When the X-rays 2b irradiated on the surface cause Bragg reflection,
The in-plane rotation mechanism 5 of the sample mounting device 50 is controlled by the control device 71.
2 is controlled to rotate the sample 3 in-plane to an angular position where Bragg reflection does not occur.

Next, the control device 71 outputs an operation command to the drive device 62 of the X-ray detector 61, moves the X-ray detector 61 in the longitudinal direction, and measures the sample surface 3a by the same procedure as described above. X-rays 2 reflected at different positions in region 4a
The intensity of c is sequentially detected, and data analysis is performed over the entire measurement region 4a in the X direction.

If a local change is found in the X-ray reflectivity thus obtained, the two-dimensional position sensitive detector 63 is mounted on the driving device 64. Then, the goniometer 40 rotates the θ of the sample 3 and the 2θ of the X-ray detector 60.
The rotation is performed, and the intensity change data of the X-ray 2c reflected in the measurement area 4a of the sample surface 3a is recorded in the recording area 63a of the two-dimensional position sensitive detector 63 as shown in FIG.

The recording of the X-ray intensity change data is as follows.
For example, θ rotation of the sample 3 and X
An operation command synchronized with the 2θ rotation of the line detection unit 60 is output to a driving device 64 of the two-dimensional position-sensitive detector 63, and the driving device 64 is driven to drive the two-dimensional position-sensitive detector 63. 2 while moving in the Z direction.

If the intensity change data of the X-ray 2c is recorded as described above, the amount of change in the angle of θ rotation of the sample 3 and the amount of movement of the two-dimensional position sensitive detector 63 in the Z direction are related. X-ray 2 to two-dimensional position sensitive detector 63
The reading range of the intensity change data can be improved by expanding the recording range of the intensity change data c in the Z direction.

The recorded data of the X-ray intensity was obtained from the sample surface 3
The X direction of the measurement area 4a is set as the horizontal axis, and the irradiation angle of the X-ray 2b on the sample surface 3a is set as the vertical axis (θ), and is recorded in the recording area 63a of the two-dimensional position sensitive detector 63 (FIG. 5
reference). The irradiation angle θ of the X-ray 2b on the vertical axis represents a value converted from the amount of movement of the two-dimensional position sensitive detector 63 in the Z direction and the amount of change in the angle of θ rotation.

Recording area 6 of two-dimensional position sensitive detector 63
When the recording of the intensity change data of the X-ray 2c reflected on the sample surface 3a is completed on the sample 3a, the control device 71 outputs an operation command to the horizontal drive mechanism 54 of the sample mounting device 50, and drives the mechanism 54. Then, the sample 3 is translated in the Y direction, and the measurement area is changed from the area 4a to the area 4b. The control device 71 outputs an operation command to the driving device 64 of the two-dimensional position-sensitive detector 63 to move the two-dimensional position-sensitive detector 63 in the Z direction in FIG. The recording area of the change data is changed from the area 63a to the area 63b.

Then, the control device 71, as described above,
An operation command is output to the goniometer 40 to drive the sample angle scanning mechanism 41 and the detector arm angle scanning mechanism 42 of the goniometer 40 to rotate the sample 3 by θ and the X-ray detector 60 by 2θ. Then, a signal synchronized therewith is output to a driving device 64 of the two-dimensional position-sensitive detector 63, and the driving device 64 is driven to move the two-dimensional position-sensitive detector 63 in the Z direction. 5 recording area 63b
X-ray 2c with the irradiation angle θ of X-ray 2b as a parameter
The intensity change data is recorded.

Further, the measurement data in another elongated measuring area 4c on the sample surface 3a is recorded in the recording area 63c of the two-dimensional position sensitive detector 63 by the same operation as described above. FIG. 5 shows the two-dimensional position-sensitive detector 63.
The case where the intensity change data of the X-rays 2c reflected by the measurement areas 4a to 4c are respectively recorded in the three recording areas 63a to 63c is shown, but the scanning range of the irradiation angle θ of the X-rays 2b is narrowed, or By using a large-sized imaging plate, the number of measurement areas can be easily increased.

Finally, the intensity change data of the X-rays 2c recorded in the two-dimensional position sensitive detector 63 is read off-line by using a known or well-known imaging plate reader, and the X-rays 2b are irradiated to the same. A normal X-ray reflectance curve with the angle θ as a parameter is displayed.

<Second Embodiment> FIG. 6 is a perspective view showing an X-ray reflectivity measuring apparatus according to a second embodiment of the present invention. The upstream side of the sample 3 (from the X-ray source 10 to the entrance slit 3)
6) has the same configuration as that of the X-ray reflectance measuring apparatus 1 according to the first embodiment, and FIG. The X-ray reflectivity measuring apparatus 100 of the second embodiment shown in FIG.
21 and the reflection X of the two-dimensional position-sensitive detector 121.
The recordable area of the line intensity data is expanded. Therefore, the number of recording areas described above can be easily increased, and more efficient X-ray reflectivity measurement can be performed.

Since the two-dimensional position-sensitive detector 121 includes the driving drum 122, the weight is larger than that of the two-dimensional position-sensitive detector 63 of the first embodiment. For this reason, in the present embodiment, the scanning mechanism of the two-dimensional position-sensitive detector 121 by the detector arm is used so that angle scanning can be performed without difficulty even in such a two-dimensional position-sensitive detector 121. , The scanning mechanism of the goniometer 110 as shown in FIG. 6 is employed.

That is, in this goniometer 110,
X-ray detector 120 including two-dimensional position sensitive detector 121
The detector scanning table angle scanning mechanism 112 for performing the angle scanning of the above is not provided as a coaxial rotation mechanism with the sample angle scanning mechanism 111 for performing the angle scanning of the sample 3, and is independently installed at a different position on the support table 114.

The sample mounting device 50 is mounted on the sample angle scanning mechanism 111 as in the first embodiment described above.
The scanning of the angle (θ) between the X-ray 2b taken out by the asymmetric reflection member 30 and the sample surface 3a is enabled.

On the other hand, a detector angle scanning table 113 is mounted on the detector scanning table angle scanning mechanism 112, and an X-ray detection unit 120 is mounted on the detector angle scanning table 113. The detector angle scanning table 113 is provided with an arc-shaped rail 112 provided on the detector scanning table angle scanning mechanism 112.
a, and the scanning table 113 scans along the rail 112a, so that the X-ray detection unit 120 can rotate 2θ around the θ rotation axis of the sample 3. . The scanning table 113 has a built-in rotation mechanism for the drive drum 122 described above. The rotation mechanism drives the two-dimensional position-sensitive detector 121 to rotate, thereby changing the measurement area 4 on the sample surface 3a. It is possible to change the recording area of the two-dimensional position sensitive detector 121 corresponding to.

The X-ray detector 120 has an X-ray detector 123 and an X-ray shield 124 on the upstream side of the optical path of the X-ray 2c with respect to the two-dimensional position sensitive detector 121.
An X-ray shield 124 is provided between the line detector 123 and the two-dimensional position sensitive detector 121.

That is, when the intensity of the X-rays 2c reflected from the sample surface 3a is detected by the X-ray detector 123, the driving mechanism 125 moves the X-ray shielding plate 124 onto the optical path of the X-rays 2c, and the two-dimensional The X-ray 2c is prevented from being incident on the position sensitive detector 121, while the sample surface 3a
When the intensity of the X-ray 2c reflected from the X-ray is recorded on the two-dimensional position sensitive detector 121,
The X-ray shielding plate 124 is moved out of the optical path of the line 2c, and the X-ray 2
c is incident on the two-dimensional position sensitive detector 121.

The first and second embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and the technical features of the present invention described in the claims are not limited. Of course, various changes can be made according to the design and the like within a range not departing from the idea.

For example, as the optical element used in the monochromator 20 for monochromaticizing the X-rays 2 emitted from the X-ray source 10, one Bragg reflection by one flat plate single crystal is used. Alternatively, a configuration may be adopted in which a channel cut crystal using Bragg reflection twice is used. In that case, the X-ray 2 emitted from the X-ray source 10 and the X-ray 2a emitted from the monochromator 20 become parallel. Alternatively, as shown in FIG. 7, a configuration may be adopted in which the monochromatic X-rays 2a having higher intensity are extracted by replacing the multilayer tilted parabolic mirror 130 and the Ge (220) asymmetric channel cut crystal 131.

In the above-described embodiment, the data recorded on the imaging plate is read by the off-line reading device. However, the two-dimensional position-sensitive detectors 63 and 121 are surrounded by the laser and photoelectrons. It is also possible to adopt a device in which a reading mechanism including a multiplier and a light source for erasing are provided in parallel, and data is recorded, read, and erased online and read sequentially and repeatedly.

[0071]

As described above, according to the present invention,
Since the length of the X-ray emitted from the X-ray source is extended to the sample surface by the asymmetrical reflection member, the X-ray irradiation area on the sample surface is expanded, and the area on the sample surface that can be measured at once can be measured. The area can be enlarged.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an X-ray reflectometer according to a first embodiment of the present invention.

FIG. 2 is a front view showing the same X-ray reflectometer.

FIG. 3 is a schematic diagram for explaining the principle of asymmetrical reflection by an asymmetrical reflection member.

FIG. 4 is a perspective view showing a driving direction of an asymmetric reflection member by a driving device.

FIG. 5 is a diagram illustrating an example of a recording area of a two-dimensional position-sensitive detector.

FIG. 6 is a perspective view showing a configuration of an X-ray reflectometer according to a second embodiment of the present invention.

FIG. 7 is a plan view showing a modified example of the present invention.

FIG. 8 is a schematic diagram for explaining the principle of X-ray reflectivity measurement.

FIG. 9 is a graph showing an example of an X-ray reflectance curve.

FIG. 10 is a schematic diagram for explaining another principle of X-ray reflectivity measurement.

FIG. 11 is a graph showing an example of another X-ray reflectance curve.

FIG. 12 is a plan view showing a conventional X-ray reflectometer used for measuring X-ray reflectivity.

FIG. 13 is a plan view showing another conventional X-ray reflectometer used for measuring X-ray reflectivity.

[Explanation of symbols]

 1: X-ray reflectivity measuring device 2: X-ray 3: sample 3a: sample surface 4: X-ray reflectivity measurement area 10: X-ray source 11: divergence limiting slit 20: monochromator 21: divergence limiting slit 30: asymmetrical reflection Member 31: Surface 32: Crystal lattice plane 33: Crystal angle adjustment mechanism 34: Crystal tilt / position adjustment mechanism 35: Driving device 36: Incident slit 37: Driving device 40: Goniometer 41: Sample angle scanning mechanism 42: Detector arm scanning Mechanism 43: Width position adjustment mechanism 44: Detector arm 50: Sample mounting device 51: Sample support 52: In-plane rotation mechanism 53: Stage 54: Horizontal drive mechanism 55: Width drive mechanism 60: X-ray detector 61: X-ray detector 62: Driving device 63: Two-dimensional position sensitive detector 64: Driving device 65: Detection slit 70: Control system 71: Control device 7 : Storage device 73: Display device 100: X-ray reflectance measuring device 110: Goniometer 111: Sample angle scanning mechanism 112: Detector scanning table angle scanning mechanism 113: Detector angle scanning table 114: Support table 120: X-ray detector 121: two-dimensional position sensitive detector 122: drive drum 123: X-ray detector 124: X-ray shielding plate 125: drive mechanism 130: multilayer tilted parabolic mirror 131: Ge (220) asymmetric channel cut crystal

Claims (5)

[Claims] An X-ray reflectivity measuring apparatus for monochromaticizing a line-focused X-ray through a monochromator and irradiating the X-ray with a sample surface and detecting the X-ray reflected on the sample surface. By disposing an asymmetrical reflection member that reflects X-rays at an asymmetrical angle on the X-ray optical path between the monochromator and the sample, and allowing the X-rays to enter the asymmetrical reflection member at an arbitrary angle, An X-ray reflectometer, wherein the X-rays enlarged in the longitudinal direction of the line focus are taken out from the asymmetric reflection member and irradiated on the sample surface. 2. An X-ray source having a line focus, a monochromator for monochromaticizing X-rays emitted from the X-ray source, and an asymmetric reflection member for expanding the X-rays emitted from the monochromator in a longitudinal direction of the line focus. A goniometer that holds the sample and adjusts the incident angle of X-rays incident on the surface of the sample, the goniometer having at least a θ-axis, and an X-ray detector that detects X-rays reflected on the surface of the sample. X-ray reflectometer. 3. The X-ray reflectometer according to claim 2, wherein the sample is moved on a plane including the θ axis of the goniometer and along the surface of the sample to change the irradiation area of the X-ray on the surface of the sample. An X-ray reflectivity measuring apparatus, comprising: an X-ray irradiation area changing unit for performing the above operation. 4. The X-ray reflectance measuring apparatus according to claim 2, wherein the X-ray detection unit includes a two-dimensional position-sensitive X-ray recording unit and an incident angle of the X-ray with respect to a sample surface. In synchronization with the scanning of the goniometer,
an X-ray reflectivity measuring apparatus characterized in that the X-ray reflectivity is rotated by θ and the X-ray recording means is moved on the X-ray detecting section. 5. An X-ray reflectivity measuring method for monochromaticizing line-focused X-rays via a monochromator and irradiating the X-rays on the sample surface, and detecting the X-rays reflected on the sample surface. On the other hand, the monochromatic X-rays are made incident on an asymmetrical reflection member that reflects the X-rays at an asymmetrical angle, so that the X-rays enlarged in the longitudinal direction of the line focus are taken out from the asymmetrical reflection member and irradiated on the sample surface. An X-ray reflectivity measuring method, comprising: