JPH0747541A - Processing of single crystal - Google Patents

Abstract

PURPOSE:To realize the highly accurate azimuth processing of a single crystal having a special crystal azimuth. CONSTITUTION:When the surface 3 of a single crystal 1 different from the specific surface thereof is processed, the crystal surface 2 parallel to the surface azimuth A of the processing surface 3 and inclined within a range of an angle thetaof + or -10 deg.C from the processing surface 3 is set to a reference surface and the alignment of the single crystal 1 is performed using the reference surface 2 to process the processing surface 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single crystal orientation processing method.

[0002]

2. Description of the Related Art A single crystal grown by a pulling method or the like has its orientation deviated from the seed crystal by a few degrees, and the shape of the shoulder or tail differs from ingot to single crystal. When slicing a crystal ball), slicing is performed after the orientation is accurately set. Specifically, first, the end face of the single crystal ball is processed, the single crystal ball is accurately oriented by X-ray diffraction using this end face, and then the end face is processed (reference surface processing) and The orientation flat processing is performed, and the slice processing is performed based on the reference plane.

By the way, if the actual processed surface is a surface capable of X-ray reflection, for example, if it is an X surface, a Y surface, a Z surface, etc., slice processing can be performed without any problem. However, when slicing a single crystal ball having a special crystal orientation, X-ray reflection cannot be obtained on the processed surface, so after measuring the orientation on a surface parallel to the processing orientation and having strong X-ray reflection,
The goniometer is rotated to match the processing direction, or the processing direction is adjusted with a Laue device that is difficult to obtain the direction accuracy.

For example, in the case of a 64 ° Y LiTaO ₃ single crystal, even if orientation is performed in the Z plane, it is necessary to rotate it by 26 ° with a goniometer to match the processing orientation, and a rotation error of the goniometer appears. Since it is easy, processing accuracy of less than a minute is difficult, and it is difficult to confirm the orientation of the sliced wafer. In particular, regarding the tilt angle of the plane direction, the X-ray reflection intensity of the X-ray diffractometer is reduced and the direction error is increased because the measurement surface is tilted.

This is because in addition to the X-ray source of the X-ray diffractometer being linear, the measurement surface is, for example,
When tilted at 15 ° or more, the absorption coefficient of LiTaO ₃ single crystal and L
This is because iNbO ₃ single crystals and the like have weak reflection intensity, which makes it difficult to measure orientation.

[0006]

The accuracy of the crystal orientation in the slicing process of a single crystal as described above is not so important in a Si wafer or the like, but it is an oxide used in surface acoustic waves or vibrators. For (piezoelectric) single crystals, azimuth accuracy of a minute or less is required. However, with the conventional azimuth processing method as described above, it is extremely difficult to perform processing with accuracy of less than a minute when X-ray reflection cannot be directly obtained on the processing surface, and particularly when the inclination angle is large. It was a fine process.

From the above, 36 ° Y LiTaO ₃ , 36
° Y LiNbO ₃ , 41 ° Y LiNbO ₃ , 64 ° Y LiNbO ₃ , 131
There is a strong demand for the appearance of a processing method that enables highly accurate orientation processing of a single crystal body having a special crystal orientation such as ° Y LiNbO ₃ .

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a single crystal processing method which realizes highly accurate orientation processing of a single crystal body having a special crystal orientation. I am trying.

[0009]

A method for processing a single crystal according to the present invention is a method for processing a crystal orientation of a single crystal, wherein when a surface having a crystal orientation different from a specific plane is processed, In parallel, and the inclination from the processed surface is a crystal plane within ± 10 ° as a reference plane, after performing the alignment of the single crystal body using the reference plane, characterized in that the processed surface is processed There is.

[0010]

[Function] For example, when processing the end face of a 36 ° Y LiTaO ₃ single crystal, when the goniometer is turned from the Y-axis, the reflection intensity of the tilt angle cannot be sufficiently obtained, and the angle of the goniometer is rotated to rotate 36 °. As the error increases, the balance of the goniometer becomes poor, and the deviation when pressed during processing also increases. On the other hand, for example, as shown in FIG. 1, if the (011 (bar) 2) plane 2 of the LiTaO ₃ single crystal 1 is used as a reference plane, it is 33 ° Y plane, so the difference angle is 3 °.
There is only a small degree, and even when the tilt angles are matched, a sufficient reflection intensity can be obtained with a normal X-ray intensity (for example, 10 kV, 10 mA). Also, in the end face processing of a 64 ° Y LiNbO ₃ single crystal, when it is rotated by 26 ° from the Z axis, the tilt angle does not have the reflection intensity and the orientation is adjusted by the back laue method, which is inaccurate. After that, there was no way to align the orientation other than checking the orientation of each wafer,
If the (011 (bar) 8) plane is used as the reference plane, it is only offset by about 5 ° from the machined surface, so sufficient reflection intensity can be obtained,
The tilt angle can be adjusted with accuracy of less than a minute, and the surface accuracy can be significantly improved.

As described above, when processing the surface of the single crystal body whose crystal orientation is different from the specific surface, as shown in FIG. 1, the surface orientation of the processing surface 3 (indicated by arrow A in the drawing) By using the crystal plane 2 that is parallel and has an inclination θ within ± 10 ° from the processing plane 3 as a reference plane and aligning the single crystal body 1 using this reference plane 2, 36 ° Y LiTaO ₃ , 36 ° Y LiNbO ₃ , 4
A single crystal body having a special crystal orientation such as 1 ° Y LiNbO ₃ , 64 ° Y LiNbO ₃ , 131 ° Y LiNbO _{3 and} the like can be accurately aligned. By performing the surface processing after the alignment as described above, the surface accuracy can be significantly improved. Therefore, for example, slicing of a single crystal ball can be performed accurately, wafer processing can be performed efficiently, and a wafer with a highly accurate orientation can be obtained. The arrow B in FIG. 1 indicates the crystal orientation of the single crystal body 1.

FIG. 2 shows the relationship between the angle of difference between the machined surface and the reference surface and the azimuth accuracy. The difference between the machined surface and the reference surface is ±
If the angle is within 10 °, the reflection intensity can be obtained at the normal level of X-ray output even if the single crystal body is rotated to the left or right, and as is clear from FIG. Processing can be performed.

The specific surface referred to in the present invention is, for example, X
A surface on which X-ray reflection can be taken directly, such as a surface, a Y surface, and a Z surface.

[0014]

EXAMPLES Examples of the present invention will be described below.

Example 1 A 36 ° Y LiTaO ₃ single crystal ball having a diameter of 3 inches × 100 mm was fixed to a goniometer, and the end face was first processed by several mm. After processing, the angle of the X-ray diffractometer is adjusted to the reflection angle of the (011 (bar) 2) surface. In addition, the angle on the sample side is adjusted using the reference plate. In this embodiment, the (011 (bar) 2) plane whose deviation (difference angle) from the 36 ° Y plane, which is the machined surface, is 3 ° 4'is used as the reference plane.

Next, the goniometer is attached to the X-ray diffractometer, and the LiTaO ₃ single crystal ball of the sample is first adjusted to the position of the maximum X-ray intensity on the left and right. 90 degree 3-axis goniometer
Rotate to the left, then to the right 90 °, and change the tilt so that the maximum peak appears at the same position on the left and right, and adjust the bearing.

In this way, the crystal orientation of the (011 (bar) 2) plane is adjusted within 10 ″, and then 3 °
The orientation of the LiTaO ₃ single crystal ball is adjusted to 36 ° Y by shifting 4 ′. After that, the LiTaO ₃ single crystal ball is fixed with a jig, and the end face processing machine performs accurate end face processing.

By the above operation, the LiTaO ₃ single crystal ball, which has been subjected to the end face processing accurately, is subjected to the orientation flat processing,
36 ° Y LiTaO ₃ single crystal ball with wire saw 0.85
Sliced into mm width.

When the crystal orientations of the sliced wafers thus obtained were examined, it was confirmed that they were all processed with high precision within 30 ″.

Example 2 A 64 ° Y LiNbO ₃ single crystal ball having a diameter of 3 inches × 110 mm was fixed to a goniometer, and the end face was first processed by several mm. After processing, adjust the angle of the X-ray diffractometer to the angle of (011 (bar) 8) plane reflection. In addition, the angle on the sample side is adjusted using the reference plate. In this embodiment, the (011 (bar) 8) surface whose deviation (difference angle) from the 64 ° Y surface, which is the processed surface, is 4 ° 45 'is used as the reference surface.

Next, the goniometer is attached to the X-ray diffractometer, and the LiNbO ₃ single crystal ball of the sample is first adjusted to the position of the maximum X-ray intensity on the left and right. 90 degree 3-axis goniometer
Rotate to the left, then to the right 90 °, and change the tilt so that the maximum peak appears at the same position on the left and right, and adjust the bearing.

In this way, after adjusting the crystal orientations of the (011 (bar) 8) plane within 10 ″ respectively, 4 ° 4
The orientation of the LiNbO ₃ single crystal ball is adjusted to 64 ° Y by shifting 5 ′. After that, the LiNbO ₃ single crystal ball is fixed with a jig, and the end face processing machine performs accurate end face processing.

By the above operation, the LiNbO ₃ single crystal ball whose end face was accurately processed was subjected to orientation flat processing,
64 ° Y LiNbO ₃ single crystal ball 0.85 with wire saw
Sliced into mm width.

When the crystal orientations of the obtained sliced wafers were examined, it was confirmed that they were all processed with high precision within 32 ″.

Comparative Example 1 The same 64 ° Y LiNbO ₃ single crystal ball as in Example 2 was fixed to a goniometer, and the end face was first processed by several mm. After processing, the back Laue method is used for alignment, and then the angle of the X-ray diffractometer is adjusted to the reflection angle of the (0006) plane. In addition, the angle on the sample side is adjusted by the reference plate.

Next, the goniometer was attached to an X-ray diffractometer, the orientation of the LiNbO ₃ single crystal ball of the sample was adjusted so as to match the (0006) plane, and then the LiNbO ₃ single crystal ball was jigged. Fix and perform end face processing with the end face processing machine. After this, LiNbO
₃ Single crystal balls were subjected to orientation flat processing and further 64 ° Y L
The iNbO ₃ single crystal ball was sliced with a wire saw to a width of 0.85 mm.

When the crystal orientation of the obtained sliced wafer was examined, it was confirmed that the orientation was not accurately processed because it was shifted to the left and right by 15 'and the inclination was shifted by 25'.

In the above embodiment, 36 ° Y LiT
The examples of applying the present invention to the processing of aO ₃ single crystal and 64 ° Y LiNbO ₃ single crystal have been described, but the present invention is not limited to these, and 36 ° Y LiNbO ₃ and 41 ° Y LiNbO _{3 are used} .
₃ , 131 ° Y LiNbO ₃ etc. are also processed with high precision by using a crystal plane parallel to the plane orientation of the machined surface and having an inclination of ± 10 ° from the machined surface as the reference plane. be able to. For example, in the case of 36 ° Y LiNbO ₃ single crystal, the (011 (bar) 2) plane as the reference plane (angle difference from the machined surface: 3 ° 4 ')
If a 41 ° Y LiNbO ₃ single crystal is used, (0
11 (bar) 2) surface (difference with processed surface: 7 ° 56 ′), 131 °
If the Y LiNbO ₃ single crystal is used as the reference plane and the 128 ° Y plane is used, it is possible to perform orientation processing with high accuracy.

[0029]

As described above, according to the single crystal processing method of the present invention, a single crystal body having a special crystal orientation can be processed with high precision and reproducibility. As a result, for example, a single crystal wafer having excellent crystal orientation accuracy can be obtained with good reproducibility, which greatly contributes to the stabilization of the characteristics of SAW devices, vibrators, and the like.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a method for processing a single crystal according to the present invention.

FIG. 2 is a diagram showing a relationship between a difference angle between a processed surface and a reference surface and azimuth accuracy.

[Explanation of symbols]

 1 …… single crystal 2 …… reference plane 3 …… processing surface A …… plane orientation of processing surface B …… crystal orientation of single crystal θ …… inclination of reference surface from processing surface

Claims (1)

[Claims] 1. A method for processing a crystallographic orientation of a single crystal body, wherein when a surface having a crystallographic orientation different from a specific surface is processed, it is parallel to the surface orientation of the processed surface and the inclination from the processed surface is within ± 10 °. 2. The method for processing a single crystal, wherein the crystal plane is used as a reference plane, the single crystal body is aligned using the reference plane, and then the processed surface is processed.