JPS62223656A - Crystal orientation determining device - Google Patents

Abstract

PURPOSE:To simplify the entire part of a device and to reduce the size and cost thereof by aligning the center of a sample to the center of a goniometer and constituting the device in such a manner that either an X-ray tube or detector can be rotated at a prescribed angle with the center of the goniometer by a rotating mechanism. CONSTITUTION:The rotating mechanism 14 is so provided that the X-ray detector 12 rotates at the desired angle around the center P of the goniometer 13. An X-ray tube angle setting mechanism 15 for rotating the X-ray tube 11 at the prescribed angle around the center Q of the incident X-ray flux on a meter 13 and a detector angle setting mechanism 16 for rotating the detector 12 at the prescribed angle around the center R thereof are provided. The sample rotating mechanism 18 is provided to a sample base 17 having the central axis common with the central axis of the meter 13. The sample 1 is rotated at the prescribed angle by the mechanism 18. A collimator 20 determines the direction where the incident X-ray flux of the X-ray tube 11 progresses. The max. quantity of the diffracted X-rays is thus detected by the detector 12, by which the crystal lattice plane of the sample 19 is determined. The device is simplified and reduced in size in the above-mentioned annex.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a crystal orientation determination device that determines the crystal orientation of a single crystal sample such as silicon or quartz using X-ray diffraction. .

(Prior Art) In order to use a single crystal such as silicon or quartz as an industrial product such as a semiconductor or an oscillator, it is necessary to cut the surface so that it forms a specific angle with respect to the crystal lattice plane. For this purpose, it is necessary to know the crystal lattice plane of the sample, and the most commonly used method for determining the crystal lattice plane uses X-ray diffraction. The method for determining the crystal lattice plane of a sample using this X-ray diffraction is shown in FIG. That is, when X-rays are incident on the sample 1, when the incident angle of the X-rays reaches a certain angle θ, the X-rays are diffracted by the atoms A. The angle at this time is called a diffraction angle, and the angle θ is determined by the following (1).

nλ−26sinθ −<+)n=1.
2.3. Integer λ = X-ray wavelength (included) d = lattice spacing (included) θ = diffraction angle (degrees) Therefore, silicon for semiconductor substrates is generally grown into ingot-shaped monoliths by growing seed crystals. Conventionally, this X
A goniometer shown in FIG. 4 that utilizes line diffraction is used.

In this conventional goniometer, the point where the center of the incident X-ray flux of the X-ray tube 1 is on the surface of the sample ingot 2 is defined as the goniometer center P, and the incident X-ray flux center and the goniometer center P
The line connecting these lines is taken as the X-axis, passes through point P, and the axis perpendicular to this X-axis is taken as the y-axis. Also, if the radius of the ingot 2 is r, then from the goniometer center P to X [=rsinθ]
, Y (rsinθ) becomes the ingot center O. Then, the sample rotation mechanism 3 is centered around this ingot center.
The ingot 2 is rotated by this. Further, in the goniometer, the X-ray detector 4 is arranged so as to be rotatable by a predetermined angle around the rotation center P thereof.

In such a conventional crystal orientation determination device, the X-ray detector 4 is first installed at a position of 2θ with respect to the diffraction angle (θ), and the incident X-ray beam is irradiated from the X-ray tube 1 onto the surface of the sample 2. While rotating, the sample 2 is rotated around the ingot center O. Therefore, when the crystal lattice plane of the sample ingot 2 becomes θ degrees with respect to the X axis, the detector 4 installed at a position 2θ degrees toward the goniometer center P detects the diffracted Indicates line strength. Therefore, the rotational position of the ingot 2 at which this maximum X-ray intensity is exhibited is determined to be the crystal lattice plane.

However, in such a conventional crystal orientation determination device, since the rotation center 0 of the sample ingot is located at a different position from the rotation center P of the goniometer, there is a difference between the incident X-ray flux center and the goniometer center as well as the goniometer center. The positional relationship with the center of rotation of the sample must also be set accurately. Furthermore, since the center of rotation of the sample is determined by two elements, XY and Y, as shown in Figure 3, an XY table is normally used to determine the top 11 of the XYITI. If the squareness is not perfect, X and Y cannot be set independently. However, for example, when using a silicon ingot of 8 inches x 650 mm as a sample, the offer is approximately 5
0k (also becomes +).

Therefore, as mentioned above, in addition to the goniometer rotation mechanism, a high-precision ingot rotation and X, Y direction movement mechanism is required, but the ingot rotation mechanism has small eccentricity and the rotation center axis is the same as the rotation center axis of the goniometer. High parallelism must be maintained, and the XY table must also maintain high perpendicular accuracy of the X and Y axes, and the X and Y dimensions must be set with high accuracy. So, about 5
It is extremely difficult to realize a mechanical configuration for determining the position of a suspended sample up to 0 ko with high precision as described above, and there is a problem that errors occur. In addition, when efforts were made to minimize errors, there was also the problem that the mechanism became complicated and large.

(Problems to be Solved by the Invention) As described above, in the conventional crystal orientation determining apparatus, the center of rotation of the sample is located at a different position from the center of rotation of the goniometer. In addition to the center of the goniometer, the positional relationship between the center of the goniometer and the center of the sample must be set with high precision.

Since a Y-axis moving table is used, there is a problem that the mechanism becomes complicated and large.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a crystal orientation determination device that can simplify and downsize the mechanism for setting the positional relationship of each component. With the goal.

[Configuration 1 of the Invention (1,100 to Solve the Problems) In the crystal orientation determination device of the present invention, the rotation center of the goniometer is made to coincide with the sample rotation center, and an X-ray tube and an X-ray tube are placed around the center of the goniometer. A rotation line is provided to rotate at least one of the detection tubes by a predetermined angle, and an Xm tube angle setting mechanism is provided to rotate the X-ray tube by a predetermined angle around the center of the incident X-ray flux. A detector angle setting mechanism is provided to rotate the detector by a predetermined angle around the center of the detector.
Furthermore, the sample is rotated relative to the goniometer.

(Function) In the crystal orientation determination device of the present invention, the center of the sample is set to coincide with the center of the goniometer, the Xla tube or detector is rotated by a predetermined angle with respect to the center of the goniometer, and the Rotate the wire tube at a specified angle,
The detector angle setting mechanism rotates the detector by a predetermined angle,
The incident X-ray flux from the X-ray tube is set to enter the surface of the sample at a predetermined diffraction angle, and the diffracted X-rays are set to enter the detector, and in this state, the goniometer or the sample is rotated about its rotation center. and the detector determines the crystal lattice plane of the sample by detecting the maximum amount of diffraction X19.

(Example) Hereinafter, this invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 shows one embodiment, in which the XIQ tube 11 and
In the goniometer 13 equipped with the line detector 12,
A rotation mechanism 14 is provided so that the X-ray detector 12 can be rotated by a desired angle around the goniometer center P.

Further, on the goniometer 13, an X-ray tube angle setting mechanism 15 for rotating the X-ray tube 11 by a predetermined angle around the incident X-ray flux center Q, and an X-ray tube angle setting mechanism 15 for rotating the X-ray tube 11 by a predetermined angle around the incident X-ray flux center Q;
A detector angle setting mechanism 16 is provided for rotating the detector by a predetermined angle around the detector.

In addition, the sample stage 17 shares the same central axis as the goniometer 13.
is equipped with a sample rotation mechanism 18, and the sample F119 on the sample stage 17 is rotated by a predetermined angle by this sample rotation mechanism 18.

The traveling direction of the incident X-ray flux of the xMJ tube 11 is determined by the collimator 20, and the X-ray tube angle setting mechanism 1
5 rotates the collimator 20 as well as the rotation of the X-ray tube 11, and determines the traveling direction of the incoming X-ray flux by this X-ray tube angle setting mechanism 15.

The operation of the crystal orientation determination device having the above configuration will be described next. As shown in FIG. 2, a cylindrical sample ingot 19 is placed on a sample stage 17 so that its center coincides with the rotation center P of the goniometer 13. The diffraction angle of the sample 19 is the value θ shown by the above formula (1), and the distance from the rotation center P to the incident X-ray flux center Q is the distance IL2 from the rotation center P to the center R of the detector 12. , when the radius of the sample 19 is r, the X-ray tube 11 is rotated by β1 degree by the X-ray tube angle setting mechanism 15 about the input mxa bundle center Q as an axis. Further, the detector 12 is rotated by β2 degrees from the rotation center P of the goniometer 13 by the detector angle setting mechanism 16. This rotation angle β1. β2 is determined by the following equation (2), <3).

Further, the X-ray detector 12 is rotated clockwise from the X-axis by (2θ+β1+β2) degrees with respect to the center P of the goniometer 13 by the rotation mechanism 14, and set to the position shown in FIG.

When setting the positional relationship between the X-ray tube 11, the detector 2J12, and the sample in this way, the incident X-ray flux from the X-ray tube 11 is incident on the surface of the sample 19 by the collimator 2o at the diffraction angle θ of the sample 19. I will do it.

Therefore, by driving the sample rotation mechanism 18, the sample 1
9, when the crystal lattice plane comes to the positional relationship shown in FIG. 3 with respect to the incoming DAX ray flux, the diffracted
The maximum amount will be incident on .

Therefore, when the sample 19 is rotated while the detector 12 detects the incident xI9m, the detector 12 indicates the
When the line group reaches its maximum value, the crystal lattice plane of the sample can be determined.

In the above embodiment, the sample ingot 19 was rotated by the sample rotation mechanism 18 and the maximum value of the diffracted X-rays m incident on the X-ray detector 12 was measured. Considering the case where the sample 19 is a ff1ffi product and it is difficult to control its rotation, the sample 19 is fixed and
It is also possible to provide a rotation mechanism that rotates the wire tube 11 and the detector 12 around the center P of the goniometer 13 in the arrangement shown in FIG. When rotating the X-ray tube and detector in this manner, the rotation mechanism can be simplified because these devices are lighter than silicon or crystal ingots.

Further, the angle setting of the X-ray detector 12 does not need to be very strict, as long as it is sufficient to know the maximum value of the incident X-ray m, and therefore the angular accuracy of the detector angle setting mechanism 16 is It will be relatively rough.

[Effects of the Invention] This invention aligns the center of the sample with the center of the goniometer, rotates either the X-ray tube or the detector by a predetermined angle with respect to the center of the goniometer by rotational line drawing, and The X-ray detector can be rotated by a predetermined angle around the center of the X-ray flux, and the X-ray detector can be rotated by a predetermined angle around the center of the detector.
The beam is set to be incident on the sample surface, the diffracted X-rays from the sample surface are incident on the detector, and one of the X-ray tubes, the detector, and the sample is set relative to the other. It is designed to be able to rotate around the center of the goniometer.

Therefore, since the goniometer center and the sample rotation center are shifted from each other as in the prior art, there is no need for an XY two-axis parallel translation e mechanism for setting the positional relationship between the sample center and the goniometer center based on the radius of the sample.

Because of this, the high-precision XY2'ld control mechanism that was necessary for moving heavy samples in the two axes of XY can be omitted, simplifying the entire device, making it possible to downsize and reduce costs. be.

[Brief explanation of drawings]

Fig. 1 is a different composition of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of the above embodiment, Fig. 3 is an explanatory diagram of the diffraction phenomenon of X-rays in a sample, and Fig. 4 is a mechanical diagram of a conventional example. be. 11... X-ray tube 12... X-ray detector 13... Goniometer 14... Rotation mechanism 15... X-ray tube angle setting mechanism 16... Detector angle setting mechanism

Claims (1)

[Claims] (1) A goniometer comprising an X-ray tube, an X-ray detector, and a rotation mechanism that rotates at least one of the X-ray tube and the X-ray detector by a predetermined angle around a central axis; and the X-ray tube. an X-ray tube angle setting mechanism that rotates the X-ray detector by a predetermined angle about the center of the incident X-ray flux; a detector angle setting mechanism that rotates the X-ray detector by a predetermined angle about the center of the detector; crystal orientation determination comprising: a sample stage on which a specimen is placed so as to align with the rotation axis of the goniometer; and a sample rotation mechanism that rotates the sample stage relative to the goniometer around the rotation axis of the goniometer. Device.