JP2547294B2 - Method and apparatus for growing raised single crystal rod convex portion - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grown single crystal rod convex structure capable of automatically grinding a convex portion formed on a crystal habit line of a grown single crystal rod (ingot). Part grinding method and apparatus.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a semiconductor wafer from a single crystal rod (ingot) pulled by the FZ method, the CZ method, etc., first, the outer periphery of the single crystal rod is ground by a cylindrical grinding device to form a cylindrical shape. Then, the cylindrically ground single crystal rod is thinly sliced in the direction perpendicular to the axis. By the way, the outer surface of the single crystal rod as it is pulled up has a peculiar hump (convex portion) in each axis direction.
m may also be protruding.

In the grinding by the cylindrical grinding device, it is usually impossible to grind this single crystal ingot as it is immediately by the cylindrical grinding device, since it can usually grind only about 1.5 to 2 mm in one grinding. Therefore, it was necessary to remove the bumps (projections) before cylindrical grinding.

As a method of removing the bumps (projections),
A conventionally known cylindrical grinding device (Japanese Patent Application Laid-Open No. 2-129505, Japanese Patent Application Laid-Open No. 2-131849, etc.) is used to previously grind the bumps (projections) (reciprocating several times for large bumps). It was necessary.) Or, an automatic grinder is used to selectively grind with the skill and intuition of the operator.
In the former case, the processing capacity of the cylindrical grinding machine is reduced, and in the latter case, it is very unstable depending on the degree of skill of the operator whether or not the grinding of the hump is accurately removed. there were.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and prevents deterioration of the processing capacity of the cylindrical grinding device, and it is accurate and stable without depending on the skill and intuition of the operator. Accordingly, it is an object of the present invention to provide a grown single crystal rod convex portion grinding method and apparatus capable of efficiently performing convex portion (cobb) removal grinding of a single crystal rod.

[0006]

In order to solve the above problems, in the method for grinding a convex portion of a single crystal rod according to the present invention, the grown single crystal rod is substantially centered on both end faces and on the rod axis. Hold it rotatably, and first hold the single crystal ingot at least 36
The image is rotated by 0 °, and the position of the crystal habit line on the outer surface of the single crystal rod is detected and stored by the image pickup camera and the image pickup camera memory analyzer.
Then, while operating the imaging camera and the imaging camera memory analysis device, in order to grind the habit line and the convex portion in the vicinity thereof, the convex portion is ground by rotating the crystal habit line around the habit line in the forward and backward directions in a constant angle range. The same operation is performed for each crystal habit line over the entire length in the rod axis direction.

A single-crystal-rod convex-grinding device of the present invention is a device for holding a grown single-crystal rod rotatably at approximately the center of both end faces and on the rod axis, and at least 360 single crystal rods. ° Rotating means, detection memory analysis means for detecting and storing the position of the crystal habit line on the outer surface of the single crystal rod and the position of the convex portion near the crystal habit line, and the convex portion near the crystal habit line A center is provided with a means for rotating it forward and backward in a constant angle range forward and backward, a means for grinding the convex portion over the entire length in the rod axis direction for each crystal habit line, and a command portion for sequentially operating the means. The convex portion grinding described above can be automatically executed.

[0008]

In the present invention, the unevenness of the outer surface of each single crystal rod in the axial direction and each crystal habit line is detected by an image pickup camera, for example, a CCD camera, and this is stored in a computer. It is possible to grind the convex portions (humps) larger than or equal to any value) selectively and at high speed.

Further, the function of the present invention can be easily added to the cylindrical grinding machine, and by this addition, the cylindrical grinding machine can exhibit a grinding capacity more than double the conventional processing capacity.

[0010]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an example of the overall configuration of the device of the present invention, and FIG. 2 is a schematic perspective view of the device of the present invention.

The single crystal rod (ingot) W is substantially centered on both end faces and on the rod axis by the clamp rotating shafts 2 extending inwardly from a support A installed on the floor. Under the condition that it is rotatably held, it is subjected to automatic convex part grinding processing.

In FIG. 2, reference numeral 3 denotes a V block on which a single crystal ingot W is placed, which is vertically movable by a cylinder C. The clamp rotating shaft 2 is rotationally driven by a motor 2M. A rotary encoder E is attached to the motor 2M to detect the rotation angle of the motor 2M.

Reference numeral 4 is a grinding unit provided corresponding to the single crystal rod W, which is a grinding wheel, for example, a diamond wheel 6
have. The grinding wheel 6 is rotatable by a shaft 8. The shaft 8 and the drive shaft 10 of the motor 6M are connected by a belt 12, and the motor 6M rotationally drives the grinding wheel 4.

Reference numeral 14 is an inverter connected to the motor 6M and controls the motor 6M so that grinding can always be performed with a constant force.

A speed controller 16 is connected to the inverter 14 and controls the rotation speed of the motor 6M so that the current value becomes constant according to the fluctuation of the current value.

The grinding unit 4 is movable in the front-rear direction and the left-right direction with respect to the ingot W. 18
Is a first ball screw, which is rotated by a motor 18M and serves to move the grinding unit 4 in the front-back direction with respect to the single crystal rod (ingot) W.

Reference numeral 20 is an inverter connected to the motor 18M so that the motor 18M can always perform grinding with a constant force.
M is controlled. A potentiometer 22 is connected to the motor 18M and serves to detect the distance in the front-rear direction with respect to the single crystal rod (ingot) W of the grinding unit 4.

Reference numeral 24 is a second ball screw, which is a motor 2
The grinding unit 4 is rotated by 4M and moves in the left-right direction with respect to the single crystal rod W. 26
Is a potentiometer connected to the motor 24M and serves to detect the distance in the front-rear direction with respect to the single crystal rod (ingot) W of the grinding unit 4.

Reference numeral 28 denotes an image pickup camera, for example, a CCD camera, which operates to rotate the single crystal rod (ingot) W to detect the crystal habit line from the irregularities on the surface of the single crystal rod (FIG. 4). As the crystal habit line detection device, a conventionally known crystal habit line detection sensor using X-ray diffraction can be used. The CCD camera 28 also has a function of reading the convex portions x ₁ and x ₂ (FIG. 6) of the ingot while moving in the axial direction of the single crystal rod (ingot) W. Reference numeral 30 denotes an image pickup camera memory analysis device connected to the CCD camera 28, which is a convex portion T read by the CCD camera 28.
The size, width, etc. of are analyzed.

Reference numeral 32 denotes a CRT display connected to the image pickup camera storage / analysis device 30 for displaying a shadow image read by the CCD camera 28.

Reference numeral 34 is a third ball screw, which is a motor 3
The CCD camera 28 is rotated by 4M and moves to the left and right with respect to the single crystal rod (ingot) W. Reference numeral 36 denotes a potentiometer connected to the motor 34M, which serves to detect the lateral distance of the CCD camera 28 with respect to the single crystal rod (ingot) W.

Reference numeral 37 is a sequencer for performing sequence control. The sequencer 37 is directly connected to the rotary encoder 3, potentiometer 22, potentiometer 26 and potentiometer 36.

The sequencer 37 is connected to the motor 2M via the first control circuit 38, is connected to the motor 18M and the speed controller 16 via the second control circuit 40, and is connected to the motor 24M and the third control circuit 42. And the motor 34M via the fourth control circuit 44.

Reference numeral 46 denotes a computer, which is connected to the image pickup camera storage analysis device 30 and the sequencer 37.

Next, the procedure for carrying out the method for grinding a single crystal rod convex portion of the present invention using the single crystal rod convex portion grinding device having the above-mentioned structure will be described with reference to the flow chart shown in FIG.

First, the computer 46 is supplied with grinding information for automatically grinding a single crystal rod (ingot) W pulled by a single crystal pulling apparatus (not shown). This grinding information includes, for example, the diameter of the single crystal rod (ingot) W, the grinding width, the rotation speed of the grinding wheel 6, the feed speed of the grinding unit 4, the grinding height of the convex portion (for example, 3 m).
m).

First, a single crystal rod (ingot) W is placed on the V block 3, its vertical height is adjusted by the cylinder C, and both ends of the single crystal rod (ingot) W are adjusted by the clamp rotation shafts 2 and 2. When supported, the single crystal ingot W is set horizontally and rotatably (step 100).

The crystal habit line is detected by the CCD camera 28, and its position (angle) is stored in the computer 46 (step 101).

This crystal habit line is detected by changing the height of the unevenness of the surface of the single crystal rod (ingot) which appears when the single crystal rod W is rotated once (360 °) (in the example shown, three crystal habit lines are used). Is displayed) (FIG. 4).

Next, the first crystal habit line axis is the CCD camera 2.
The single crystal ingot W is rotated to a position perpendicular to the camera axis of 8 (step 102, FIG. 5). The rotation angle θ of the single crystal ingot W at this time is set to 0.

Next, the convex portion is detected for each crystal habit line, and the order of the crystal habit line for detecting the convex portion is set to n, and the crystal habit line to be detected first is n. = 1 (step 103).

CCD camera 2 on the first crystal habit line
When the situation of the convex portion is photographed by 8, the large and small convex portions are observed as shown in FIG. 6 as the relationship between the axial direction X of the single crystal rod (ingot) W and the height r (r ₀ is a single crystal. The position of the outer surface of the bar is shown. Of these, only when the size of the convex portion is a predetermined value Δr (for example, 3 mm) or more is detected as a grinding target (in the illustrated example, x ₁ and x ₂ are determined as convex portions), and at the same time, the convex portion is detected. The computer 46 stores the size and position of the (step 104, FIG. 6).

When the detection and storage of the first convex portion on the crystal habit line are completed, the detection and storage of the second and subsequent convex portions on the crystal habit line are repeated until the rotation angle θ becomes 360 ° or more ( Step 105 to step 107).

When the detection and storage of the convex portion for all the crystal habit lines are completed, the convex portion is ground for each crystal habit line, and the order of the crystal habit line for performing the convex portion grinding is set to m. First, m = 1 is set for the crystal habit line to be ground (step 108).

It is determined whether or not there is a convex portion on the m-th crystal habit line (step 109), and if there is no convex portion, the single crystal rod (ingot) W is rotated to the m + 1-th crystal habit line grinding position (step). 113).

If there is a convex portion, the grinding wheel unit is moved to the convex position (step 110) and the convex portion is ground (step 111). Single crystal rod (ingot) during grinding
Before and after W, forward and reverse rotations of a certain angle ± α (for example, about 3 to 10 °) are repeated to prevent grinding residue.

When the grinding of the first convex portion on the first crystal habit line is completed, the presence or absence of the remaining convex portion on this crystal habit line is determined (step 112), and if there is still a convex portion, the convex portion is ground. Repeat (step 110 to step 111).

When all the convex portions of the first crystal habit line have been ground, the single crystal rod (ingot) W is rotated to the grinding position of the next crystal habit line (step 113, step 11).
4). Grinding of the convex portions is repeated for each crystal habit line until the number of detected crystal habit lines and the number of crystal habit lines obtained by grinding the convex portions match (m = n, step 115).

When the grinding of all the convex portions on all the crystal habit lines is completed, the single crystal rod (ingot) W is removed from the convex portion grinding device and the convex portion grinding work is completed (step 11).
6).

[0040]

As described above, according to the present invention, only the convex portion (cob) of a single crystal rod can be selectively and rapidly ground without resorting to the skill and intuition of an operator. By cylindrically grinding the treated single crystal ingot, a great effect that the cylindrical grinding work can be performed with efficiency more than double that of the conventional one is achieved.

[Brief description of drawings]

FIG. 1 is a block diagram-like explanatory view showing an embodiment of the device of the present invention.

FIG. 2 is a schematic perspective view showing an embodiment of the device of the present invention.

FIG. 3 is a flowchart showing a procedure for carrying out the method of the present invention.

FIG. 4 is a graph showing a relationship between a rotation angle of a single crystal rod (ingot) by a CCD camera and a crystal habit line position.

FIG. 5 is an explanatory diagram showing a positional relationship between a camera and a single crystal rod (ingot) when detecting a convex portion on a crystal habit line of the single crystal rod (ingot).

FIG. 6 is a graph showing the unevenness on the crystal habit line of a single crystal ingot, as a relationship between the axial direction X of the single crystal ingot and the height r.

[Explanation of symbols]

 2 Clamping axis 4 Grinding unit 6 Grinding wheel 12 Belt 14 Inverter 16 Speed controller 18 First ball screw 20 Inverter 24 Second ball screw 28 CCD camera 30 Camera memory analyzer 32 CRT display 37 Sequencer 46 Computer W Single crystal rod (ingot)

Claims (2)

(57) [Claims] 1. A grown single crystal ingot is held rotatably at substantially the center of both end faces and on the axis of the ingot, and the single crystal ingot is first rotated at least 360 °, and an imaging camera and an imaging camera memory analysis are performed. The apparatus detects and stores the position of the crystal habit line on the outer surface of the single crystal rod, and then operates the imaging camera and the imaging camera memory analysis device to grind the crystal habit line and the convex portion in the vicinity thereof. A grown single crystal rod characterized by performing convex work by rotating forward and backward in a certain angle range around the habit line and performing similar work over the entire length in the axial direction of each crystal habit line. Convex part grinding method. 2. A device for holding a grown single crystal rod rotatably at substantially the center of both end faces and on the rod axis, means for rotating the single crystal rod at least 360 °, and the outside of the single crystal rod. Detection and memory analysis means for detecting and storing the position of the crystal habit line on the surface and the position of the convex portion in the vicinity of the crystal habit line, and forward and reverse in a constant angle range before and after the convex portion in the vicinity of the crystal habit line. The method for automatically rotating the convex portion according to claim 1, further comprising: a means for rotating, a means for grinding the convex portion over the entire length in the rod axis direction for each crystal habit line, and a command portion for sequentially operating the means. A single-crystal-rod-projection-grinding device for growing grown single crystal rods.