JPH06167464A - Inspecting apparatus for cut surface of single crystal material - Google Patents

Abstract

PURPOSE:To dispense with the changing of a position of an X ray optical system and to remove a danger of the X ray beam from a worker when a single crystal material of an inspection object is changed to the other kind in the case where an X-ray optical system of a double crystal method capable of inspecting a cut surface with high accuracy is used. CONSTITUTION:An apparatus for inspecting a cut surface of a single crystal material comprises an X-ray tube 9 emitting an X-ray, a first crystal 13 diffracting the X-ray to a single crystal material 2 and an X-ray counter 6 which detects the X-ray diffracted by the single crystal material 2. On the basis of a diffraction angle of the X-ray detected by the X-ray counter 6, the apparatus measures a deviation angle between a cut surface 2a and an internal crystal lattice face. A channel cut crystal is utilized for the first crystal 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single crystal material cut surface inspection apparatus for measuring an angular deviation of a single crystal material cut surface from an internal crystal lattice plane.

[0002]

2. Description of the Related Art In recent years, single crystal materials have been widely used industrially. For example, a crystal plate used as an oscillation source and a Si (silicon) single crystal wafer used for semiconductors are known as single crystal materials. These single crystal materials are generally formed by cutting a rod-shaped raw material into a thin film of, for example, about 0.2 mm. Now, taking a crystal plate as an example, when the inclination angle of the cut surface of the crystal plate with respect to the crystal lattice plane inside the crystal plate changes variously, the characteristics of the crystal plate change accordingly.

Even if the raw material of the quartz crystal is cut by the cutting device under a fixed equipment condition, the inclination angle of the cut surface of each crystal plate with respect to the internal crystal lattice plane actually has a considerable deviation. Therefore, in the case of randomly using a plurality of cut quartz plates without selecting them, it is not possible to obtain uniform output characteristics for each quartz plate. Therefore, normally, the inclination angle of the cut surface of each of the cut crystal plates is measured, and the crystal plates are used by classifying them according to an angular deviation within a predetermined range.

As described above, a cut surface inspection apparatus utilizing X-ray diffraction is widely used as an apparatus for measuring the inclination angle of the cut surface of a single crystal material such as a quartz plate with respect to the crystal lattice plane. As such a cut surface inspection device, there is a so-called slit optical system device as shown in FIG. 3, for example. In this apparatus, X-rays are emitted from the point-focused or line-focused X-ray source 1.
This X-ray is composed of a continuous X-ray component and a narrow characteristic X-ray component having a remarkably strong intensity.
The X-rays are made monochromatic by passing through the Ni (nickel) foil filter 4, that is, only the characteristic X-ray component is extracted to the output side (right side in the figure). The extracted X-rays are directed by the slit 3 and enter the single crystal material 2.

The single crystal material 2 has a cut surface 2a or 2b.
Is always supported at a fixed position by the goniometer 5 in a state where the position is fixed by an appropriate clamp means.
This goniometer 5 can rotate the single crystal material 2 around an axis L extending in the direction perpendicular to the paper surface, that is, so-called ω rotation, and can read the incident angle δ of X-rays on the crystal surface. Normally, the angle can be measured with a reading accuracy of about 30 seconds. The diffraction condition is satisfied when the incident direction of the X-ray becomes the Bragg angle θ with respect to the crystal lattice plane of the single crystal material 2, and the X-ray is diffracted in the direction of the diffraction angle 2θ with respect to the incident X-ray. An X-ray counter 6 as X-ray detection means is arranged in this diffraction direction, and the X-ray counter 6 detects diffracted X-rays.

When the single crystal material 2 is rotated by ω within a minute angle range, a known rocking curve, that is, a diffraction intensity curve as shown in FIG. 6 is obtained. If the peak position θ1 of the rocking curve is read and compared with the reference position,
The deviation of the tilt angle of the cut surface 2a or 2b of the single crystal material 2 with respect to the crystal lattice plane can be known.

However, in this slit optical system cut surface inspection apparatus, although the divergence of X-rays is suppressed by using the slit 3, the divergence cannot be completely removed, and the rocking curve (FIG. 6) is inevitable. The full width at half maximum W has a spread of, for example, about 3 to 5 minutes. As a result, it was difficult to measure with high accuracy.

In order to solve this problem, for example, there is a so-called two-crystal method cut surface inspection apparatus as shown in FIG. In this device, the divergence angle of X-rays emitted from an X-ray source 1 is regulated by a slit 3, and after diffracted by a first crystal 7, the X-rays are incident on a second crystal, that is, a single crystal material 2. The measurement itself performed while rotating the single crystal material 2 by ω is the same as that of the device of the slit optical system shown in FIG. The illustrated apparatus has an optical system structure in which two crystals 7 and 2 are arranged in parallel (+, −). Usually, the first crystal 7 has the same crystal lattice spacing (d value) as the single crystal material 2. ) With a perfect crystal without lattice defects.

According to the device of the two-crystal method, the X-ray is the first
The X-ray is monochromated and collimated (that is, the divergence of the X-ray is suppressed) by diffracting with a crystal, and therefore, the full width at half maximum W in the rocking curve can be suppressed within, for example, several seconds to several tens of seconds. it can. As a result, highly accurate cut surface inspection becomes possible. However, this device has the following drawbacks.

In recent years, for example, when considering a crystal plate, various cutting angles of the cut surface with respect to the crystal lattice plane are used to change the AT cut plate, SC cut plate, X cut plate, and Y cut plate.
A wide variety of cut plates, Z-cut plates and other cut plates are manufactured. Each of these various cut plates has a unique X-ray diffraction angle, and therefore, when changing the second crystal 2 to be inspected to a second crystal having a different crystal lattice plane index, the second crystal is changed each time. With the first crystal 7 having the same lattice spacing as the crystal, the position of the second crystal 2, that is, the entire goniometer must be rearranged in accordance with the diffraction angle of the first crystal 7. This work is extremely troublesome, and adjusting the optical axis of the X-ray optical system after the movement is also very troublesome.

When a single crystal material 2 having a large X-ray diffraction angle, such as a Z-cut plate, is used, the first crystal 7 necessarily has the same crystal lattice plane, so that the X-ray is used. The diffraction angle becomes large. In this case, as shown in FIG. 5, the diffraction line R diffracted by the first crystal 7 moves further toward the front side than in the case of FIG. Normally, the worker stands on the front side (the lower side in the figure) of the apparatus to perform the work, and therefore it is very dangerous for the worker that the diffraction line R advances toward the front side as shown in FIG. . If a beam stopper is provided in front of the worker to avoid this danger, the workability will be extremely deteriorated.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the conventional cut surface inspection apparatus and is capable of highly accurate cut surface inspection.
Even when the X-ray optical system of the crystal method is used, it is not necessary to change the arrangement of the X-ray optical system when changing the single crystal material to be measured to another type, and the operator can use the X-ray beam. The purpose is to eliminate the risk.

[0013]

In order to achieve the above object, a cut surface inspection apparatus for a single crystal material according to the present invention provides an X-ray source which emits an X-ray and an X-ray emitted from the X-ray source. A channel cut crystal is used as the first crystal in a cut surface inspection apparatus having a first crystal that diffracts toward a single crystal material and an X-ray detection unit that detects X-rays diffracted by the single crystal material. I am trying.

As known per se, a channel-cut crystal is an X-ray reflection element in which a groove is formed in a crystal block such as quartz, germanium or the like, and the inner surfaces of both side walls forming the groove are used as an X-ray reflection surface. Is.

[0015]

The single crystal material which is the object of the cut surface inspection, that is, the X-ray incident on the second crystal is reflected by the channel cut crystal, is monochromatic, and further is collimated, that is, its divergence is suppressed. . Therefore, the full width at half maximum of the rocking curve obtained by the diffraction line from the single crystal material becomes extremely narrow, and therefore the inclination angle of the cut surface with respect to the crystal lattice plane can be measured with extremely high accuracy.

X incident on the channel-cut crystal
The direction of the line and the direction of the X-ray emitted therefrom are always the same regardless of the crystal material forming the channel cut crystal. Therefore, the position of disposing the single crystal material may be always a constant position regardless of the material of the single crystal material, and it is not necessary to change it for each material. Furthermore, if the direction of the X-ray emitted from the channel-cut crystal is shifted from the direction toward the worker, the worker is not exposed to the X-ray direct beam, which is very safe.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a cut surface inspection apparatus for a single crystal material according to the present invention. The figure shows the apparatus viewed from above. This cut surface inspection device has an X-ray tube 9 arranged on a frame 8, a goniometer 5, and an X-ray counter 6 as X-ray detection means. The inside of the X-ray tube 9 is kept in a vacuum, and the filament 10 and the target 11 are housed inside the X-ray tube 9. The target 11 is formed of, for example, copper (Cu). A clamp plate 12 is provided on the goniometer 5.
The single crystal material 2 such as a crystal plate is fixed to the clamp plate 12 by vacuum suction, mechanical clamping means or any other fixing method. in this case,
The cut surface 2a of the single crystal material 2 is positioned in close contact with the front surface of the clamp plate 12. The goniometer 5 rotates the single crystal material 2 around an axis L passing through the cut surface 2a,
That is, it can be rotated by ω. Further, the incident angle δ of X-ray can be measured.

Between the X-ray tube 9 and the goniometer 5, a slit 3 and a channel cut crystal 13 acting as a first crystal are fixedly arranged. The channel-cut crystal 13 is made of the same material as the single crystal material 2 and is a perfect crystal having no lattice defect or the like. And its shape is
As shown in FIG. 2, one rectangular parallelepiped crystal block 1
By digging the groove M at the center of the groove 4, the side wall 14a and 14b are formed on both sides of the groove M. Inner wall surfaces of the both side walls 14a and 14b facing each other are used as X-ray reflecting surfaces.

The operation of the cut surface inspection apparatus having the above structure will be described below. The thermoelectrons emitted from the filament 10 that generate heat when energized are targeted 11
X-rays are radiated from there. Radiated X
After the divergence of the line is limited by the slit 3, the line is incident on the channel-cut crystal 13 and the two reflection surfaces 14
The light is sequentially reflected or diffracted at a and 14b. Due to this diffraction, monochromatic X-rays without divergence, for example, K of Cu
Alpha rays are extracted. The extracted X-rays are incident on the single crystal material 2 that is the second crystal and are diffracted there when the diffraction condition is satisfied. This diffracted X-ray is detected by the X-ray counter 6.

The goniometer 5 rotates the single crystal material 2 by ω within a minute angle range. At this time, the X-ray counter 6 detects the peak value of the diffracted X-ray intensity, and the X-ray incident angle δ at that time is read. By comparing the angle δ at this time with a reference angle value, the inclination angle of the cut surface 2a with respect to the crystal lattice surface is measured.

In the present embodiment, since the so-called two-crystal method using the first crystal 13 and the second crystal 2 is adopted, highly accurate cut surface inspection is performed. Moreover, the first crystal 1
Since a channel cut crystal is used as 3,
Even if the material of the crystal 13 changes, the direction of X-rays emitted therefrom is always constant. Therefore, even when the single crystal material 2 to be inspected is changed to various materials having different X-ray diffraction angles, the position where the single crystal material 2 is arranged is fixed at a substantially constant position, and the optical system is enlarged. No need to relocate. Furthermore, although the operator 15 usually stands on the front side of the apparatus and performs various operations, the channel cut crystal 13
The X-rays emitted from the device are set so as not to go toward the worker 15, and the setting does not change even when the material of the channel cut crystal 13 changes. Therefore, there is no risk of the worker 15 being exposed to the X-ray direct beam, which is safe.

Although the present invention has been described with reference to one embodiment, the present invention is not limited to this embodiment. For example, the crystal material of the channel cut crystal 13 is not necessarily the same as the single crystal material 2, that is, the same as the second crystal. In some cases, another type of single crystal having the same lattice plane spacing as the lattice plane spacing (d value) of the single crystal material 2 can be used. The number of channel-cut crystals is not limited to one, and four crystals (crystal collimates) can be used by combining two channel-cut crystals, for example.

[0023]

According to the present invention, since the X-ray optical system of the two-crystal method is used, highly accurate cut surface inspection is possible. Further, since the channel-cut crystal is used as the first crystal, the direction of the X-ray emitted from the channel-cut crystal can always be fixed to a fixed direction even when the first crystal is changed to an arbitrary different type. Therefore, it is not necessary to change the arrangement of the X-ray optical system when changing the single crystal material to be inspected to another type. Furthermore, by previously shifting the direction of the X-ray beam emitted from the channel-cut crystal from the direction toward the worker, the risk of the worker being exposed to the X-ray direct beam can be reliably eliminated.

[0024]

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a cut surface inspection device for a single crystal material according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a channel cut crystal.

FIG. 3 is a plan view showing an embodiment of a conventional cut surface inspection apparatus for a single crystal material.

FIG. 4 is a plan view showing another example of a conventional cut surface inspection apparatus for a single crystal material.

5 is a plan view showing the arrangement of the X-ray optical system when the material of the single crystal is changed in the conventional example shown in FIG.

FIG. 6 is a diagram showing an example of a rocking curve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray source 2 Single crystal material (2nd crystal) 6 X-ray counter (X-ray detection means) 13 Channel cut crystal (1st crystal) 14 Crystal block 14a Side wall reflection surface 14b Side wall reflection surface

Claims (1)

[Claims] 1. An X-ray source that emits X-rays, a first crystal that diffracts the X-rays emitted from the X-ray source toward a single crystal material, and an X that detects the X-rays diffracted by the single crystal material. A cut surface inspection device for a single crystal material, which has an X-ray detection means and measures an angular deviation of a cut surface of the single crystal material with respect to an internal crystal lattice plane from an X-ray diffraction angle detected by the X-ray detection means. A cut surface inspection device for a single crystal material, wherein a channel cut crystal is used as the first crystal.