JPH085008B2 - Single crystal plane orientation correction method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crystal polishing technique, for example, a technique effectively applied to a method for correcting a plane orientation of a semiconductor single crystal by a lapping apparatus.

[Prior Art] In the manufacture of a semiconductor device, since an element is formed on a lattice plane having a predetermined orientation, high precision is required for the crystal orientation of the surface. Generally, in order to obtain a highly accurate surface crystal orientation, it depends largely on the accuracy at the time of cutting, but it is difficult to increase the accuracy at the time of cutting in the case of a small and amorphous crystal, for example, a CdTe crystal, It was necessary to correct the plane orientation after cutting.

Conventionally, the plane orientation of the crystal has been corrected by using a jig as shown in FIG. 6, for example.

That is, the jig shown in FIG. 6 has a cylindrical holding ring 1
And a cylinder 2 which is arranged at the center of the holding ring 1 and is fixed by three adjusting screw groups 3a and 3b which are respectively attached to the upper end portion and the lower end portion.
Then, the plane orientation is corrected by the piston at the bottom of the cylinder 2.
The crystal 4 is attached to the lower surface of 2a, this jig is fixed to the stage of the X-ray orientation measuring device, the surface of the crystal 4 is irradiated with X-rays, and its reflection pattern is observed to obtain the pattern. After adjusting the adjustment screw groups 3a and 3b so as to match the orientation pattern and tilting the crystal, the crystal 4 is mounted on the polishing platen of the lapping device with the crystal 4 still attached to the jig, and the crystal plane of the desired orientation appears. It was done by polishing. At this time, the crystal 4 on the lower surface of the piston 2a is pressed against the polishing surface of the surface plate by an appropriate pressure by the spring 2b built in the cylinder 2 to be polished.

[Problems to be Solved by the Invention] In the conventional plane orientation correction method using a jig as shown in FIG. 6, the tilt of the crystal 4 is not adjusted by the six adjusting screws 3a and 3b. Since the adjustment work is delicate and tedious and requires skill, the correction accuracy depends on the processing accuracy of each part of the jig where the correction accuracy is complicated, and the jig itself is expensive to improve the correction accuracy. was there.

An object of the present invention is to provide a polishing technique capable of correcting a crystal orientation with high accuracy and reproducibility without using skill by using a jig having a simple structure and a low cost.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses a rigid plate having three height-adjustable conical pointers at its peripheral edge as a jig, and the center of the plate is used as a jig. A crystal is attached, the surface of the crystal is observed by an X-ray azimuth measuring device to detect the inclination of the lattice plane, and each surface connecting the tips of the three pointers is parallel to the desired lattice plane. After adjusting the height of the pointer independently, put the crystal on the surface of the jig on the polishing surface plate of the polishing device, and polish until the polishing surface of the surface plate touches the tips of all pointers. did.

[Operation] According to the above-described means, the heights of the three pointers that determine the exposed surface can be adjusted accurately by using a dial gauge or the like, so that no skill is required and the heights of the three pointers can be adjusted. Workability is improved because it only needs to be adjusted.

Further, the jig structure is simple and the number of parts is small, so that a highly accurate jig can be manufactured at low cost.

[Embodiment] An embodiment of the surface orientation correction method according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a structural example of a jig used in this embodiment.

The jig 10 of this embodiment includes a rigid disc-shaped plate 11
Pointers 12a, 12b, 12c, which serve as three reference pins having conical tips, are provided on the peripheral edge of the and facing upward at regular intervals. At least the tips of the pointers 12a to 12c are made of a high-hardness material, and a screw portion 13 is formed on the outer periphery thereof as shown in FIG.
Through holes 14a, 14b, 14c formed so as to penetrate vertically
Is screwed into a female screw formed on the inner wall of the.

Further, presser nuts 15a to 15c are screwed to the rear ends (lower ends in the figure) of the pointers 12a to 12c, respectively.
After independently rotating a to 12c to adjust the height of the tip,
The pointer can be fixed by tightening the holding nuts 15a to 15c.

The correction of the crystal plane orientation by the jig 10 configured as described above is performed as follows.

That is, first, the surface of the crystal 4 is observed by an X-ray azimuth measuring device to detect the inclination with respect to a desired lattice plane, and then the crystal 4 is attached to the center of the upper surface of the plate 11 using wax or the like. At that time, it is desirable that one side bc of the crystal 4 and the straight line connecting the pointers 12b and 12c be parallel to each other.

Next, according to the detected tilt angle, three pointers 12a-1
Adjust the height of 2c respectively. Specifically, in FIG. 1, if the surface indicated by the symbol abcd on the crystal 4 is the actual surface and the symbol ijkl is the lattice surface desired to be projected on the surface, then ab and ij form The angles α and the angle β formed by bc and jk are measured using, for example, an X-ray diffractometer. Then, for example, determine the height Ha of the pointer 12a according to the thickness of the crystal to be obtained, and after fixing it at that height, the following formula Thus, the heights Hb and Hc of the pointers 12b and 12c are obtained.

In the above equation, L is the distance between the pointers 12a, 12b, 12c.

Pointer 12b, 1 so that the height is Hb, Hc obtained from the above formula
Turn 2c to adjust the height, and then tighten the presser nuts 15b and 15c. In the above case, the height of each of the pointers 12a to 12c can be adjusted by using the dial gauge 23 attached to the center of the support plate 22 supported by the three legs 21a to 21c as shown in FIG. The legs 21a to 21c are placed on the plate 11 of the jig to keep them parallel, and the contact point 23a of the dial gauge 23 is brought into contact with the tips of the pointers 12a to 12c one after another to display the display portion 23b.
You can adjust the height while watching the scale.

In this way, the height setting accuracy of the pointers 12a to 12c depends on the accuracy of the dial gauge, but can be set with the accuracy of 1 μm. The effect of this error on the surface orientation is 7 seconds or less at L = 70 mm when α and β are sufficiently small, and the practical requirement can be satisfied.

When the height adjustment of the pointers 12a to 12c is completed as described above, the jig 10 is turned upside down in the correction ring 32 on the surface plate 31 of the lapping device as shown in FIG. 4, for example. The crystal 4 on 11 is placed so as to contact the surface plate 31, and the surface plate 31 is rotated while supplying abrasive grains to the polishing surface,
Polishing is performed until all the pointers 12a to 12c on the plate 11 come into contact with the surface plate.

The results of performing the plane direction correction polishing on 12 CdTe single crystals according to the above procedure are shown below.

In the experiment, a jig having a diameter of the plate 11 of 110 mm and a distance of the pointers 12a, 12b, 12c of 70 mm was used, and lapping was performed on a surface plate made of Pyrex glass using alumina abrasive grains. The polished surface was the (111) plane, and the deviation of the plane orientation of the crystal surface before and after the correction was measured by an X-ray orientation measuring device. FIG. 5 shows the measurement results. From the figure, it can be seen that all deviations of 0.2 to 0.5 ° before polishing could be corrected within 0.05 °. This sufficiently satisfies the plane orientation accuracy currently required for compound semiconductor single crystals.

In the jig of the above embodiment, the screw portion 13 is formed on the outer circumference of the pointers 12a to 12c so that the height can be adjusted, but the height adjusting means is not limited to the screw, and for example, a predetermined value can be used. A method of exchanging with a pointer having a height of 1 may be used.

[Effect of the Invention] As described above, according to the present invention, a crystal is attached to a jig having at least three height-adjustable pointers,
The orientation of the surface of the crystal is detected, and the heights of the pointers are independently adjusted so that the surface connecting the tips of the three pointers becomes parallel to the desired lattice plane. Since I tried to polish until it touched the tip of
Since the heights of the three pointers that determine the exposed surface can be adjusted accurately by using a dial gauge or the like, no skill is required, and since it is only necessary to adjust the heights of the three pointers, workability is improved. improves. In addition, the jig structure is simple and the number of parts is small, so that a highly accurate jig can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structural example of a jig used for carrying out the crystal face orientation correcting method according to the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a perspective view showing a configuration example of a gauge used for adjusting the height of the pointer of the jig, FIG. 4 is a perspective view showing an example of a lapping device, and FIG. 5 shows the method of the present invention. FIG. 6 is an explanatory view showing the deviation of the plane orientation before and after the modification of the crystal that has been applied and modified, and FIG. 6 is a perspective view showing a configuration example of a conventional jig used for the plane modification. 10 ... Jig, 11 ... Plate, 12a-12c ... Pointer,
4 ... Crystal.

Claims (1)

[Claims] 1. A lattice, in which a crystal is attached to a jig having at least three height-adjustable reference pins, the orientation of the surface of the crystal is detected, and a surface connecting the tips of the three reference pins is a desired lattice. After independently adjusting the height of each reference pin so that it becomes parallel to the surface, polishing is performed until the polishing surface comes into contact with the tips of all the reference pins. Direction correction method.