JP4330047B2 - Method and apparatus for measuring ingot runout - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ingot runout measuring method and apparatus for a CZ (Czochralski) type semiconductor single crystal pulling apparatus.
[0002]
[Prior art]
For example, in a CZ type silicon single crystal pulling apparatus, in order to obtain a high quality single crystal by accurately controlling the crystal orientation and cross-sectional shape of a silicon ingot growing from the tip of a seed crystal, Centering is required so that the center of rotation of the crucible and the center of the shaft exactly coincide with each other so that the silicon ingot suspended from the tip of the seed wire does not swing around the center of rotation of the crucible.
[0003]
Conventionally, for the centering of the seed wire, a pointed conical weight of an appropriate size is hung at the tip of the seed wire, and a circle having a diameter corresponding to an allowable error range of the seed wire swing width, For example, paper with a circle of 2 to 3 mm in diameter is placed on the rotating shaft of the crucible or on the upper surface of the crucible so as to be concentric with the axis of rotation, and the wire rotation of the pull head of the CZ type silicon single crystal pulling device The seed wire is rotated at a predetermined speed (5 to 25 rpm) by the mechanism portion, and it is visually checked whether or not the tip portion of the conical weight suspended from the tip of the seed wire is within a circle indicating an allowable error range. It was judged by confirming with.
[0004]
[Problems to be solved by the invention]
However, in the case of the conventional method described above, since the determination of pass / fail depends on the visual observation of the operator, it is difficult to make an accurate and objective determination, and the fluctuation width can be expressed numerically or left as data. There was a problem that it was not possible. In addition, there is a problem that ingot runout in each process (neck process, crown process, body process, and tail process) accompanying the growth of the ingot cannot be measured individually.
[0005]
The present invention has been made to solve the above-mentioned problems, and in the CZ type semiconductor single crystal pulling apparatus, the swing width of the ingot can be accurately measured numerically, and each step accompanying the growth of the ingot An object of the present invention is to provide an ingot runout measuring method using a dummy ingot and an apparatus thereof capable of individually measuring runout characteristics in a neck process, a crown process, a body process, and a tail process.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the method of the present invention provides a CZ type semiconductor single crystal pulling apparatus for pulling a seed wire connected to a pull head portion at a predetermined speed while rotating the seed wire at a predetermined rotation speed. Ingot run-out measurement method, which has almost the same shape and weight as the actually manufactured ingot, and the ingot shape in the neck process, crown process, body process and tail process of the actually manufactured ingot A dummy ingot formed according to the above is suspended from the tip of the seed wire, and the rotating dummy is rotated while the seed wire is rotated at a predetermined speed by the wire rotating mechanism of the pull head of the CZ type semiconductor single crystal pulling apparatus. the horizontal amplitude of the ingot, intercepted laser beam by a portion of the outer peripheral portion of the dummy ingot Detected by using the laser light emitting element and the laser light receiving element which is positioned adjusted so that is obtained by the seek the deflection characteristics of the ingot from the amplitude of該得was dummy ingot.
[0007]
In addition, the apparatus of the present invention is an ingot shake measuring apparatus for a CZ-type semiconductor single crystal pulling apparatus that pulls up a seed wire connected to a pull head portion at a predetermined speed while rotating the seed wire. In the neck process, the crown process, the body process, and the tail process of the actually manufactured ingot, which has almost the same shape and the same weight as the actual ingot to be suspended from the tip of the seed wire . The dummy ingot formed in accordance with the ingot shape and the crucible portion were installed, and the horizontal swing width of the dummy ingot was adjusted so that the laser beam was blocked by a part of the outer peripheral portion of the dummy ingot. a shake detection means for detecting by using a laser light emitting element and the laser light receiving element, the position adjustment of the shake detecting means Position adjusting means, data collection / analysis means for collecting the fluctuation width data of the dummy ingot detected by the fluctuation detection means, and generating a predetermined fluctuation characteristic of the ingot from the collected fluctuation width data, and the data It comprises a display means for outputting ingot vibration characteristics obtained by the collection / analysis means in a predetermined method and format.
[0008]
The dummy ingot used in the shake measuring method and apparatus of the present invention is an assembly type in which the whole is divided into a plurality of small blocks, and the neck process, crown process, body process and tail process of the actually manufactured ingot are performed. It is desirable to combine the small blocks in accordance with the ingot shape in each process. Further, as the shake detecting means used in the shake measuring apparatus of the present invention, it is desirable to use a laser transmission type sensor capable of detecting the shake width of the dummy ingot in a non-contact manner.
[0009]
In the case of the above configuration, a dummy ingot is used instead of an actually manufactured ingot, and the horizontal deflection width of the ingot is accurately measured and recorded as numerical data, and the necessary runout of the ingot is calculated from this measurement data. Characteristics can be obtained. For this reason, center alignment of the seed wire can be performed easily and accurately, and a high-quality ingot can be manufactured.
[0010]
In addition, when an assembly type that is divided into a plurality of small blocks is used as a dummy ingot, it is adapted to the ingot shape in each of the neck process, crown process, body process and tail process of the actually manufactured ingot. By combining the small blocks, it is possible to obtain run-out characteristics in each process as the ingot grows, and it is possible to manufacture a higher quality ingot.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an embodiment of an ingot shake measuring apparatus according to the present invention. FIG. 1 is a longitudinal sectional view showing the main structure of the embodiment, and FIG. 2 is a plan view thereof.
[0012]
In the figure, reference numeral 1 denotes a pull head portion of a silicon CZ type semiconductor single crystal pulling apparatus, and a seed wire 2 passes through a rotation drive shaft cylinder 1a of the pull head portion 1 to a wire pulling mechanism 1b in the pull head portion 1. It is connected and slowly pulled up at a predetermined speed, and by rotating the pull head unit 1 by a wire rotation mechanism unit composed of a servo driver 3, a servo motor 4 and a rotary encoder 5, the seed wire 2 is predetermined. It is configured to rotate slowly at a speed of.
[0013]
A seed chuck 6 is attached to the tip of the seed wire 2, and a dummy head 7 for measuring the swing characteristics of the ingot is suspended from the seed chuck 6.
[0014]
Reference numeral 8 in the figure denotes a crucible portion of a CZ-type silicon single crystal pulling apparatus, and a quartz glass crucible body, a silicon melting heater 9, a heat insulating material 10, and a crucible frame, not shown from the inside. A body 11 and the like are arranged. A sensor mounting jig 13 is detachably mounted and fixed on the top surface portion of the heat insulating material 10, and the swing width of the dummy ingot 7 that is rotated by being suspended by the seed wire 2 is attached to the sensor mounting jig 13. A laser light emitting element 12a and a laser light receiving element 12b of the laser transmission type sensor 12 for detection are assembled.
[0015]
The sensor mounting jig 13 is composed of a rectangular frame member 13a (see FIG. 2) surrounding the dummy ingot 7, and the left and right vertical pieces 13b and 13c are suspended from the lower surface of the frame member 13a. The laser light emitting element 12a and the laser light receiving element 12b are attached by feed screw mechanisms 13d and 13e so that their positions can be adjusted in the arrow direction. The feed screw mechanisms 13d and 13e are scaled with scales 13f and 13g so that the position can be accurately adjusted.
[0016]
Reference numeral 12c in the figure denotes a laser drive control unit that drives the laser light emitting element 12a to emit laser light L, and is a dummy ingot based on a change in the amount of laser light L received by the laser light receiving element 12b. 7 is a circuit for detecting a swing width of 7. The laser drive control unit 12c, the laser light emitting element 12a, and the laser light receiving element 12b constitute a so-called laser transmission sensor 12.
[0017]
Reference numeral 14 in the figure denotes a data collection / analysis unit configured from a personal computer or the like, which collects and records the amplitude data of the dummy ingot 7 detected by the laser transmission sensor 12, A predetermined runout characteristic of the ingot is analyzed based on the collected runout data. Reference numeral 15 denotes a display unit composed of a printer, a monitor, and the like, which outputs and displays the ingot shake characteristics generated by the data collection / analysis unit 14 in a predetermined method and format.
[0018]
3 and 4 show the detailed structure of the dummy ingot 7 suspended from the seed wire 2. 3 is a longitudinal sectional view of the dummy ingot, and FIG. 4 is a sectional view taken along line AA in FIG. The dummy ingot 7 in the illustrated example is obtained by dividing the entire dummy ingot 7 into a plurality of small blocks 71 to 7n, and these small blocks 71 to 7n are connected and assembled by screw portions 21. As the material of the dummy ingot 7, it is desirable to use aluminum which has a specific gravity close to that of silicon, is excellent in workability and strength, and is not so expensive. Aluminum has a specific gravity slightly higher than that of silicon, so it is smaller than actual silicon ingots. The shape and weight of aluminum is the same as that of actually manufactured silicon ingots, and alumite treatment is applied to the surface to prevent corrosion. It is desirable to do so. Furthermore, in order to ensure safety and to enable one person to work, it is desirable to divide so that one block is 10 kg or less.
[0019]
In this way, by making the dummy ingot 7 an assembly type composed of small blocks 71 to 7n, the shape is almost the same as the silicon ingot in each actual single crystal pulling process (neck process, crown process, body process and tail process). In addition, it is possible to easily make a dummy ingot having a weight, and it is possible to measure the vibration characteristics in a state extremely close to a silicon ingot actually manufactured.
[0020]
The two small holes 22 formed in the outer peripheral surfaces of the small blocks 71 to 7n are holes for inserting a handle 23 for turning and screwing the small blocks during assembly. Further, it is more preferable to attach a dummy neck portion 24 and a dummy seed crystal portion 25 to the crown portion constituted by the uppermost small block 71.
[0021]
Next, the ingot runout measurement operation in the above apparatus will be described.
First, prior to the start of measurement, the laser mounting jig 13 to which the laser light emitting element 12a and the laser light receiving element 12b are mounted is placed on the top surface portion of the heat insulating material 13 of the crucible portion 8 and set at a fixed position. Input / output terminals of the light emitting element 12a and the laser light receiving element 12b are connected to the laser drive control unit 12c.
[0022]
On the other hand, by combining and connecting the small blocks 71 to 7n of the dummy ingot 7 shown in FIG. 7, a dummy ingot having the same shape as that of the ingot in the pulling process intended for measurement is created. For example, when it is desired to measure the run-out characteristics of the body process during the pulling process, the small block 71 constituting the crown part and some of the small blocks 72 to 7n-1 constituting the body part are combined, and FIG. A dummy ingot 7 having the same shape as the ingot in the actual body process as shown is created.
[0023]
After the dummy ingot 7 thus created is attached to the seed chuck 6 at the tip of the seed wire 2 and suspended, the wire pulling mechanism portion 1b of the pull head portion 1 is driven to unwind the seed wire 2 and dummy As shown in FIG. 1, the ingot 7 is lowered and set so that the vibration measurement portion of the outer periphery of the dummy ingot 7 is positioned between the laser light emitting element 12a and the laser light receiving element 12b.
[0024]
Next, by operating the feed screw mechanisms 13d and 13e while looking at the scales 13f and 13g and adjusting the positions of the laser light emitting element 12a and the laser light receiving element 12b in the arrow direction, the outer peripheral portion of the dummy ingot 7 is irradiated with the laser light L. Set to block some, for example, about half. In addition, in order to perform this positioning easily, it is preferable that the planar view width | variety of the laser beam L shall be 10 mm or more. With such a laser beam width, an error in the set position of about 2 to 3 mm does not affect the measurement.
[0025]
After the dummy ingot 7, the laser light emitting element 12 a and the laser light receiving element 12 b are set at predetermined positions as described above, the seed wire 2 is attached by the wire rotating mechanism unit including the servo driver 3, the servo motor 4, and the rotary encoder 5. Rotation is started at a predetermined speed (5 to 25 rpm), and measurement of ingot runout characteristics is started.
[0026]
When the seed wire 2 rotates and the dummy ingot 7 suspended from the tip thereof starts to rotate and cannot swing in the horizontal direction, the light shielding amount of the laser light L by the dummy ingot 7 is always constant, and the laser light receiving element The amount of light received by 12b does not change.
[0027]
On the other hand, when the seed wire 2 rotates and the dummy ingot 7 suspended from the tip thereof starts to rotate and shakes in the horizontal direction, the amount of light received by the laser light receiving element 12b changes. This change in the amount of received light is proportional to the amount of shake of the dummy ingot 7, and the amount of shake of the dummy ingot 7, that is, the amount of deviation of the axis of the seed wire 2 can be detected from the change in the amount of received light.
[0028]
The light reception signal indicating the amount of shake of the dummy ingot 7 received by the laser light receiving element 12b is sent to the data collection / analysis unit 14 configured by a personal computer or the like via the laser drive control unit 12c, and the shake width of the dummy ingot 7 is transmitted. Data is sequentially sampled and collected and recorded.
[0029]
The data collection / analysis unit 14 uses the collected amplitude data of the dummy ingot 7 to generate a graph showing the relationship between the time and the deviation from the reference value (center position), for example, as shown in FIG. Further, using the rotational position information of the seed wire 2 that is generated and sent via the servo driver 3, if necessary, the change in the rotation time of each rotation of the seed wire as shown in FIG. And a graph showing a change in rotation time for each angle in one rotation of the seed wire as shown in FIG.
[0030]
The graph data generated by the data collection / analysis unit 14 is sent to the display unit 15 and printed by a printer or displayed on a monitor screen. By measuring the printed characteristic graph or the characteristic graph displayed on the monitor screen, the measurer can numerically accurately determine the amount of deviation between the rotation axis of the seed wire 2 and the rotation axis of the crucible portion 8. Can know. Therefore, accurate center alignment of the seed wire 2 can be realized, and a high-quality single crystal can be manufactured.
[0031]
In the above description, the dummy ingot 7 is assembled in the same shape as the actual ingot in the body process and the runout characteristic in the body process is measured. However, as shown in FIG. As shown in FIG. 8 (b), if assembled in the same shape as the Dale process, the run-out characteristics in the tail process can be measured. It is possible to measure the run-out characteristics of the ingot in each process as the crystal grows.
[0032]
In the case of the above embodiment, the assembly type dummy ingot 7 as shown in FIG. 3 is used. However, as shown in FIGS. 9A to 9C, for example, as shown in FIGS. A dedicated dummy ingot 7 having the same shape as the ingot shape in each of the process, body process, and tail process is individually created, and the run-out characteristics are measured using a dedicated dummy ingot for each process. Is also good.
[0033]
Further, the material of the dummy ingot 7 is not limited to the above-described aluminum, and silicon itself may be used. Furthermore, if the specific gravity is close to that of silicon, other materials such as synthetic resin may be used. Is possible.
[0034]
【The invention's effect】
As described above, according to the method and apparatus of the present invention, the deflection width of the ingot can be accurately measured numerically, so that the deviation of the rotational axis of the seed wire can be accurately and objectively determined. . For this reason, center alignment of the seed wire can be performed accurately, and a high-quality ingot can be manufactured.
[0035]
Also, by using an assembly-type dummy ingot that is divided into a plurality of small blocks and combining these small blocks, a dummy ingot having the same shape as each step of the actually manufactured ingot can be easily made. Since it was made possible, it becomes possible to individually measure the run-out characteristics in each process as the ingot grows. For this reason, in any process, the runout can be managed, and an ingot with more stable quality can be manufactured.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing the structure of an essential part of an embodiment of an ingot shake measuring apparatus according to the present invention.
FIG. 2 is a plan view of the embodiment.
FIG. 3 is a longitudinal sectional view of a dummy ingot.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is a graph showing a relationship between time and a deviation amount from a reference value (center position) of a seed wire.
FIG. 6 is a graph showing a change in rotation time for each rotation of the seed wire.
FIG. 7 is a graph showing changes in rotation time for each angle in one rotation of the seed wire.
FIGS. 8A and 8B are explanatory views of a method for measuring shake characteristics in the crown process, and FIG. 8B are explanatory views of a method for measuring shake characteristics in the tail process. FIGS.
FIGS. 9A and 9B show another example of the structure of a dummy ingot, FIG. 9A shows an example of a dummy ingot dedicated to the crown process, FIG. 9B shows an example of a dummy ingot dedicated to the body process, and FIG. It is a figure which shows the example of the dummy ingot only for a tail process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pull head part 2 Seed wire 3 Servo driver 4 Servo motor 5 Rotary encoder 6 Seed chuck 7 Dummy ingots 71-7n Small block 8 Crucible part 12 Laser type transmission sensor 12a Laser light emitting element 12b Laser light receiving element 12c Laser drive control part 13 Laser Mounting jig 14 Data collection / analysis unit 14 Display unit

Claims (2)

An ingot runout measurement method for a CZ type semiconductor single crystal pulling apparatus, wherein a seed wire connected to a pull head is pulled up at a predetermined speed while rotating at a predetermined rotational speed,
A dummy ingot that has almost the same shape and weight as the actually manufactured ingot, and is formed according to the ingot shape in the neck process, crown process, body process, and tail process of the actually manufactured ingot. Hanging on the tip of the seed wire,
While rotating the seed wire at a predetermined speed by the wire rotation mechanism part of the pull head part of the CZ type semiconductor single crystal pulling apparatus , the laser beam is set to the outer circumference of the dummy ingot. Detect using a laser light emitting element and a laser light receiving element whose position is adjusted to be blocked by a part of
An ingot runout measuring method, characterized in that a runout characteristic of an ingot is obtained from a runout width of the obtained dummy ingot. An ingot runout measurement apparatus for a CZ type semiconductor single crystal pulling apparatus configured to pull up a seed wire connected to a pull head portion at a predetermined speed while rotating at a predetermined rotational speed,
It has almost the same shape and weight as the actual ingot to be hung on the tip of the seed wire, and it matches the ingot shape in the neck process, crown process, body process and tail process of the actually manufactured ingot. A dummy ingot formed by
Installed in a crucible portion, the horizontal swing width of the dummy ingot is detected using a laser light emitting element and a laser light receiving element whose positions are adjusted so that the laser light is blocked by a part of the outer periphery of the dummy ingot. Shake detection means for
Position adjusting means for adjusting the position of the shake detecting means;
Data collection / analysis means for collecting the fluctuation data of the dummy ingot detected by the shake detection means, and generating a predetermined vibration characteristic of the ingot from the collected fluctuation data;
An ingot shake measuring apparatus comprising: a display means for outputting the shake characteristics of the ingot obtained by the data collection / analysis means in a predetermined method and format.

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