JP2000221147A - Crystal orientation angle measurement device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the crystal orientation angle of a sample with a sample surface as a reference, without including errors due to fine uneveness on the surface of the sample and the deviation of a fitting position to a sample retention part. SOLUTION: A light source 4 and a photodetector 5 are arranged so that the intensity of light from a light source 5 entering the photodetector 5 can be maximized, when a surface Sa of a sample being retained by a sample-fitting part 1 is in parallel with a light axis (a) for connecting the light source 4 to the photodetector 5, and a standard sample with a known deviation angle δ0 is fitted. An angle ω0 where the intensity of light from the light source 4 entering the photodetector 5 is maximized, and an angle ω1 where the intensity of diffraction X-rays which are detected by an X-ray diffraction system that is set at a specific angle is maximized, are measured. Then, an angle ω2 where the intensity of light is maximized similarly by fitting a sample to be measured and an angle ω3, where the intensity of diffracted X-rays is maximized are measured to obtain a deviation angle δ of the sample to be measured, based on an expression δ=δ0±(ω3-ω2)-(ω1-ω0)}.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for measuring the crystal azimuth angle of a sample such as a quartz plate used as an oscillator of a reference oscillator.

[0002]

2. Description of the Related Art As a crystal azimuth measuring apparatus of this kind, the present applicant has previously disclosed Japanese Utility Model Application No. 62-163206 (Japanese Utility Model Application Laid-Open No.
No. 67554). As shown in FIG. 5, a crystal azimuth measuring device according to the application is a goniometer 100.
The sample S is brought into close contact with and supported on the surface 101a of the sample mounting portion 101 arranged at the center of
By measuring the rotation angle of the sample mounting unit 101 when diffracted X-rays are detected by the goniometer 100 by applying a ray and projecting a ray on the sample surface Sa to detect the position of the reflected ray, The configuration is such that a deviation angle between the surface Sa and the surface 101a of the sample mounting portion is detected. That is, the rotation angle position of the sample surface Sa is obtained by projecting the light beam from the light source 102 on the sample surface Sa and detecting the light beam reflected from the sample surface Sa with the position detector 103.

[0003]

However, if there are minute irregularities on the sample surface Sa, the incident light is scattered on the same surface Sa. For this reason, there was a possibility that the reflection angle of the light beam could not be detected accurately. If the sample surface Sa has minute irregularities, the sample surface Sa attached to the sample
Also changes. Such a mounting position error also changes the direction of the light beam reflected on the sample surface.

The measurement of the crystal azimuth angle of a sample such as a quartz plate used as an oscillator of a reference oscillator is 5 × 10 ^−6.
Since measurement accuracy in the rad order is required, such measurement errors also greatly affect the reliability of the device. The present invention has been made in view of such circumstances, and has as its object to realize highly accurate crystal azimuth measurement of a sample.

[0005]

In order to achieve the above object, a crystal azimuth measuring apparatus according to the present invention comprises a sample mounting portion for holding a sample and a sample mounted on the sample mounting portion within a surface of the sample. A goniometer that rotates about the rotation axis of the goniometer, an angle detector that detects the rotation angle of the goniometer, a light source that emits light from the side of the sample, and light that is provided at a predetermined position facing the light source with the rotation axis interposed therebetween. A detector, an X-ray source that causes X-rays to be incident on the surface of the sample from a predetermined direction, and an X-ray detector that detects X-rays diffracted on the surface of the sample, and the surface of the sample held by the sample mounting unit. Is based on the fact that the light intensity from the light source incident on the photodetector becomes maximum when it is parallel to the optical axis connecting the light source and the photodetector. It is characterized by seeking.

Further, in the crystal azimuth measuring method of the present invention using the above-described apparatus, the sample is mounted on the sample mounting section, and the goniometer is rotated to maximize the light intensity from the light source incident on the photodetector. Detecting the first rotation angle with the angle detector, and rotating the sample about the rotation center to determine the second rotation angle when the intensity of the diffracted X-rays incident on the X-ray detector becomes maximum. Detecting the crystal azimuth with respect to the sample surface from the first rotation angle and the second rotation angle.

In the present invention, the angle that is parallel to the optical axis connecting the light source and the photodetector is defined as the reference angle of the sample surface. Then, since the reference angle of the sample surface is detected by detecting the light intensity from the light source incident on the photodetector, even if there are minute irregularities on the sample surface, the passing light does not cause an error due to scattering. . Further, even if the front and rear positions of the sample surface mounted on the sample mounting portion slightly change, the reference angle of the sample surface can be accurately obtained by detecting the rotation angle position showing the maximum light intensity with the photodetector. .

In the above invention, the "light source" is referred to as "second light source".
X-ray source) "to" second X-ray detector "
The crystal azimuthal angle of the sample can be measured in the same manner even if the above is changed to.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view showing the outline of the crystal orientation measuring apparatus according to this embodiment. The crystal orientation measuring apparatus includes a goniometer 2 on which a sample stage forming a sample mounting unit 1 is mounted, an angle detector 3 for detecting a rotation angle of the goniometer 2, an X-ray source 6, an X-ray detector 7, a light source 4, and A photodetector 5 is provided. The goniometer 2 rotates by ω around a rotation axis O in the sample surface Sa mounted on the sample mounting unit 1, and the rotation angle is determined by the angle detector 3.
Is detected by

The light source 4 includes a sample S held in the sample mounting section 1.
It is installed on the side of. In front of the light source 4 is provided an entrance slit 8 for converting the light beam emitted from the light source 4 into a thin parallel beam. Further, the photodetector 5 is provided on the sample surface S
The light source 4 is provided at a position opposed to the light source 4 with the rotation axis O in a. A transmission limiting slit 9 that allows only light rays incident from a predetermined direction to pass is also provided in front of the photodetector 5.
With this configuration, when the surface Sa of the sample S held by the sample mounting unit 1 becomes parallel to the optical axis a connecting the light source 4 and the photodetector 5, the light from the light source 4 incident on the photodetector 5 The light intensity is maximum.

The X-ray source 6 has a crystal lattice plane Sb (crystal lattice plane contributing to measurement, hereinafter the same) which is arranged in parallel with an optical axis a connecting the light source 4 and the photodetector 5. It is set at a position where X-rays are incident on the lattice plane Sb at an incident angle of the Bragg angle θ. In front of this X-ray source 6, X
A divergence slit (DS) 10 for limiting the divergence of the X-ray radiated from the radiation source 6 is provided, and the X-ray passing through the divergence slit 10 is irradiated on the sample. Also, the X-ray detector 7
Is set to a direction of 2θ that satisfies the diffraction condition of the crystal lattice plane Sb with respect to the incident X-ray from the X-ray source 6 as described above.

Next, a method of measuring the crystal orientation of a sample using the above-described crystal orientation measuring apparatus will be described. In this embodiment, the deviation of the crystal azimuth angle is first determined for the standard sample. The standard sample used here is a sample whose deviation angle between the surface Sa and the crystal lattice plane Sb is known. For example, a sample such as a quartz plate used as a resonator of a reference oscillator is:
The surface Sa and the crystal lattice plane Sb are processed so as to have a deviation angle of about 3 °. It is preferable that the standard sample has a deviation angle close to the deviation angle or is manufactured so that the deviation angle is close to 0 °.

First, the standard sample S is mounted on the sample mounting section 1, the goniometer 2 is rotated, and the light beam emitted from the light source 4 is detected by the photodetector 5. If the sample surface Sa is tilted with respect to the optical axis a connecting the light source 4 and the photodetector 5, the standard sample S blocks a part or all of the light rays from the light source 4 and enters the photodetector 5. The amount of light to be emitted decreases.

As shown in FIG. 1, when the surface Sa of the standard sample is parallel to the optical axis a connecting the light source 4 and the photodetector 5, the light source 4 incident on the photodetector 5 _{Has the} maximum light intensity IL (see FIG. 3). Light intensity I _L from the light source 4 incident on the light detector 5 is detected by the angle detector 3 a rotation angle omega _{0 (first} rotation angle) of which the maximum.
At this rotation angle ω ₀ , the surface Sa of the standard sample S is arranged parallel to the optical axis a connecting the light source 4 and the photodetector 5.

Subsequently, the X-ray source 6 irradiates the standard sample S with X-rays, diffracted X-rays diffracted on the crystal lattice plane Sb of the standard sample S are detected by the X-ray detector 7, and the goniometer 2 is used. rotate the intensity I _X of the diffracted X-rays incident on the X-ray detector 7 is detected by the rotation angle omega _{1 (the} second rotational angle) angle detector 3 in which the maximum. The detection of the diffracted X-rays may be performed concurrently with the detection of the light intensity from the light source 4.

From the above measurement data, a relative angle (hereinafter referred to as a standard angle) ω ₁ −ω ₀ of the crystal lattice plane Sb with respect to the reference angle ω ₀ formed by the surface Sa of the standard sample S can be obtained. The measurement accuracy of the standard angle can be improved by rotating the sample in the plane of 180 ° and repeating the above measurement, and calculating the average value.

Next, a sample (hereinafter referred to as a "measurement sample") S to be measured is mounted on the sample mounting portion 1, the goniometer 2 is rotated, and a light beam emitted from the light source 4 is detected by the photodetector 5. . If the surface Sa of the measurement sample is inclined with respect to the optical axis a connecting the light source 4 and the light detector 5, the measurement sample S blocks a part or all of the light rays from the light source 4,
The amount of light incident on the photodetector 5 decreases.

As shown in FIG. 1, when the surface Sa of the measurement sample is parallel to the optical axis a connecting the light source 4 and the photodetector 5, the light source 4 incident on the photodetector 5 _{Has the} maximum light intensity IL (see FIG. 4). Light intensity I _L from the light source 4 incident on the light detector 5 is detected by the angle detector 3 the rotation angle omega _{2 (first} rotation angle) of which the maximum.
In the rotation angle omega _2, is disposed parallel to the optical axis a surface Sa of the measurement sample S connecting the light source 4 and the photodetector 5.

Subsequently, X-rays are emitted from the X-ray source 6 toward the measurement sample S, and the X-ray diffracted on the crystal lattice plane Sb of the measurement sample S is detected by the X-ray detector 7 and the goniometer 2 rotate the intensity I _X of the diffracted X-rays incident on the X-ray detector 7 is detected by the rotation angle omega _{3 (second} rotation angle) angle detector 3 in which the maximum. The detection of the diffracted X-rays may be performed concurrently with the detection of the light intensity from the light source 4.

From the above measurement data, the relative angle ω ₃ −ω ₂ of the crystal lattice plane Sb with respect to the reference angle ω ₂ formed by the surface Sa of the measurement sample S can be obtained. This measurement sample S
The difference between the relative angle (ω ₃ −ω ₂ ) and the standard angle (ω ₁ −ω ₀ ) of the previously measured standard sample is the amount of deviation of the deviation angle of the measured sample with respect to the standard sample.

The standard angle (ω ₁₎ obtained as described above
−ω ₀ ) and the relative angle (ω ₃ −ω ₂ ) of the measurement sample S, an X-ray diffraction system (the X-ray source 6 and the X-ray detector 7) with respect to the optical axis a connecting the light source 4 and the photodetector 5. ) Are included, and cannot be directly used as the deviation angle. Therefore, the deviation angle δ of the measurement sample is set to a known deviation angle δ ₀ (for example, 0 ° or 2 ゜ 57 ′) of the standard sample used for the measurement of the standard angle, The amount of deviation ｛(ω ₃ −ω ₂ ) − (ω
₁₋ ω ₀ )｝. That is,
The deviation angle δ of the measurement sample is represented by the following equation. δ = δ ₀ ± {(ω ₃ −ω ₂ ) − (ω ₁ −ω ₀ )} When the standard sample is rotated by 180 ° in the plane and the average value of the measurements before and after the rotation is obtained, Δ ₀ in the equation may be treated as 0.

The present invention is not limited to the above embodiment. For example, the difference (δ ₁ −δ ₀ ) between the known deviation angle δ ₀ of the standard sample used for measuring the standard angle and the theoretical deviation angle δ _{1 of} the measurement sample is set as an offset amount, and the deviation angle of the measurement sample is set. δ can also be determined. In this case, when setting θ and 2θ in FIG. 2, (δ ₁ −δ ₀ )
And the deviation angle δ of the measurement sample is calculated by the following equation. δ = (δ ₁ −δ ₀ ) ± ｛(ω ₃ −ω ₂ ) − (ω ₁ −
ω ₀ )｝ In setting θ and 2θ in FIG. 2, the angle may be set in consideration of the deviation angle δ to reduce the rotation angle range of the goniometer 2.

If a laser light source is used as the light source 4, the entrance slit 8 and the transmission limiting slit 9 become unnecessary. Further, the light source 4 is replaced by a second X-ray source, and the photodetector 5 is replaced by a second X-ray detector, and the X-ray intensity from the second X-ray source incident on the second X-ray detector is reduced. Even when the maximum time is detected, the sample surface S
The rotation angles ω ₀ and ω ₂ of “a” can be detected.

When measuring a standard sample, the time and frequency of measurement of a standard sample are determined by the measurement accuracy required for the measurement and the state of environmental changes.

[0025]

As described above, according to the present invention, the direction (reference angle) of the surface of the sample is obtained by detecting the light intensity from the light source incident on the photodetector.
A highly accurate measurement of the crystal azimuth angle of the sample can be realized with reference to the sample surface, without including errors due to minute irregularities on the surface of the sample or displacement of the mounting position on the sample holder.

[Brief description of the drawings]

FIG. 1 is a plan view for explaining an embodiment of the present invention.

FIG. 2 is a plan view illustrating the embodiment of the present invention, following FIG. 1;

FIG. 3 is a diagram showing a relationship between a rotation angle of a standard sample, light intensity detected by a light detector, and X-ray intensity detected by an X-ray detector.

FIG. 4 is a diagram showing a relationship between a rotation angle of a sample, a light intensity detected by a photodetector, and an X-ray intensity detected by an X-ray detector.

FIG. 5 is a plan view showing the outline of a conventional crystal orientation measuring apparatus.

[Explanation of symbols]

 1: Sample mounting section 2: Goniometer 3: Angle detector 4: Light source 5: Photodetector 6: X-ray source 7: X-ray detector

Claims (6)

[Claims] 1. A sample mounting section for holding a sample, a goniometer for rotating a sample mounted on the sample mounting section around a rotation axis in the surface of the sample, and an angle detector for detecting a rotation angle of the goniometer. A light source that emits a light beam from the side of the sample; a photodetector provided at a predetermined position facing the light source with the rotation axis interposed therebetween; and X-rays incident on the surface of the sample at a predetermined angle. A crystal azimuth measuring apparatus comprising: an X-ray source; and an X-ray detector that detects X-rays diffracted on the surface of the sample. 2. The crystal azimuth angle measuring apparatus according to claim 1, wherein the light source is replaced by a second X-ray source, and the photodetector is replaced by a second X-ray detector. Crystal azimuth measuring device. 3. A crystal azimuth measuring method using the apparatus according to claim 1, wherein a sample is mounted on the sample mounting portion, and the goniometer is rotated to allow the light from the light source to be incident on the photodetector. A step of detecting the first rotation angle when the light intensity is maximized by the angle detector; and rotating the sample around the rotation axis so that the intensity of the diffracted X-ray incident on the X-ray detector is reduced. Detecting the second rotation angle when it reaches a maximum with the angle detector.
A crystal azimuth angle measuring method, wherein a crystal azimuth angle with respect to the surface of the sample is obtained from the rotation angle and the second rotation angle. 4. A method for measuring a crystal azimuth angle using an apparatus according to claim 1, wherein a deviation angle δ ₀ between a surface and a crystal lattice plane is provided on the sample mounting portion.
Mounting a known standard sample, and detecting the first rotation angle ω ₀ with the angle detector when the light intensity from the light source incident on the photodetector by rotating the goniometer is maximized. If, by rotating the standard sample about said rotation axis, the intensity of the diffracted X-rays incident on the X-ray detector detects the second rotation angle omega ₁ of which the maximum in the angle detector step and the specimen mounting portion fitted with a sample, said angle detecting a first rotation angle omega ₂ when the light intensity becomes the maximum from the light source by rotating the goniometer incident on the photodetector A second rotation angle ω ₃ when the intensity of the diffracted X-rays incident on the X-ray detector is maximized by rotating the measurement sample around the rotation axis. Detecting with a detector, the surface of the measurement sample by the following equation Crystal azimuth measuring method characterized by calculating the deviation angle of the lattice plane δ which. δ = δ ₀ ± {(ω ₃ −ω ₂ ) − (ω ₁ −ω ₀ )} 5. A crystal azimuth measuring method using the apparatus according to claim 2, wherein a sample is mounted on the sample mounting portion, and the goniometer is rotated to be incident on the second X-ray detector. Detecting the first rotation angle by the angle detector when the X-ray intensity from the second X-ray source is maximized; and rotating the sample about the rotation axis to detect the X-ray. Detecting, by the angle detector, a second rotation angle when the intensity of the diffracted X-rays incident on the device is at a maximum, and determining the surface of the sample from the first rotation angle and the second rotation angle. A crystal azimuth angle measuring method, wherein a crystal azimuth angle with respect to is determined. 6. A crystal azimuth measuring method using the apparatus according to claim 2, wherein a deviation angle δ ₀ between a surface and a crystal lattice plane is provided on the sample mounting portion.
Is mounted on a known standard sample, the goniometer is rotated, and the first rotation angle ω when the X-ray intensity from the second X-ray source incident on the second X-ray detector is maximized ₀ is detected by the angle detector, and the second rotation angle when the intensity of the diffracted X-ray incident on the X-ray detector is maximized by rotating the standard sample around the rotation axis. detecting ω ₁ with the angle detector, mounting a measurement sample on the sample mounting unit, rotating the goniometer, and entering the second X-ray detector from the second X-ray source. a step of X-ray intensity detecting a first rotation angle omega ₂ of which the maximum in the angle detector, and rotating the sample around the rotation axis, is incident on the X-ray detector diffraction and a step in which the intensity of X-rays to detect the second rotation angle omega ₃ when it becomes maximum at the angle detector See, crystal azimuth measuring method characterized by calculating the deviation angle δ of the crystal lattice plane relative to the surface of the sample by the following equation. δ = δ ₀ ± {(ω ₃ −ω ₂ ) − (ω ₁ −ω ₀ )}