JP3700490B2 - Seed crystal holding device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seed crystal holding device of a silicon single crystal pulling apparatus by the Czochralski method (CZ method). More specifically, the present invention relates to an apparatus for holding a seed crystal that is brought into contact with a silicon melt when growing a single crystal.
[0002]
[Prior art]
Conventionally, a Czochralski method (hereinafter referred to as CZ method) in which a silicon single crystal is grown from a silicon melt in a crucible is known as a method for growing a silicon single crystal. In this method, first, polycrystalline silicon is filled in a crucible installed in a pulling apparatus. One end of the seed crystal is brought into contact with the surface of the silicon melt obtained by heating and melting the polycrystalline silicon and partially melted. Next, the seed crystal is pulled up to create a seed squeezed portion from the silicon melt, and then the crystal is gradually thickened and grown to the target silicon rod diameter. By this method, a dislocation-free single crystal rod having a necessary crystal orientation can be obtained.
[0003]
This seed crystal is usually attached to and held by a holding device suspended from a wire. In this holding device, first, a seed crystal having a notch formed in advance on its side surface is inserted into a seed crystal insertion hole formed in the bottom of the seed chuck along the center axis of the seed chuck. In this state, the seed chuck pin is inserted into a pin hole formed perpendicular to the central axis of the seed chuck and offset from the central axis. As a result, the body portion of the seed chuck pin comes into contact with the notch portion of the seed crystal, and the seed crystal is held.
[0004]
[Problems to be solved by the invention]
However, in the conventional seed crystal holding device, the length of the silicon single crystal rod is increased, and high stress concentrates on the portion where the body portion and the notch portion of the seed chuck pin contact, The seed crystal may be damaged at the notch. In this case, since the notch portion of the seed crystal, the pin hole of the seed chuck, and the seed chuck pin are each single, the silicon single crystal rod may fall into the silicon melt. In particular, with the demand for increasing the diameter of silicon single crystal rods, the weight of silicon single crystal rods pulled by seed crystals has recently been increasing. As a result, the stress at the contact portion generated when the silicon single crystal rod is pulled up becomes larger than before, and the incidence of accidents in which the silicon single crystal rod falls is further increased.
An object of the present invention is to provide a seed crystal holding device that reduces the incidence of silicon single crystal rod dropping due to breakage of the seed crystal.
[0005]
[Means for Solving the Problems]
As shown in FIG. 1 or 2, the invention according to claim 1 is orthogonal to the center axis a and the seed crystal insertion hole 22a formed in the bottom of the chuck body 22d along the center axis a of the chuck body 22d. A seed chuck 22 having a pin hole 22b formed so as to be deviated with respect to the central axis a, and an outer diameter that can be inserted into the seed crystal insertion hole 22a. In the seed crystal holding device including the seed crystal 23 in which the portion 23a is formed and the seed chuck pin 24 that is inserted into the pin hole 22b and can be brought into contact with the notch 23a, the pin hole 22b is the center. A plurality of notches 23a are formed on the side surface of the seed crystal 23 according to the number of pin holes 22b, and seed chuck pins 24 are inserted into the plurality of pin holes 22b, respectively. And a holding device of the seed crystal, characterized in that only the body portion 24a of the seed chuck pins 24 inserted into the top of the pin hole 22b is configured so as to be in contact with the notch 23a.
In the invention according to claim 1, a plurality of notches 23 a of the seed crystal 23, a pin hole 22 b of the seed chuck 22, and a seed chuck pin 24 are provided, and the uppermost notch 23 a and the body of the seed chuck pin 24 are provided. The seed crystal 23 is held on the seed chuck 22 by contact only at 24a. As a result, even if the uppermost notch 23a is damaged and the seed crystal 23 slips down, the notch 23a located next to the uppermost part and the body 24a of the seed chuck pin 24 come into contact with each other, and the seed crystal Since 23 is held, the silicon single crystal rod can be prevented from dropping.
[0006]
The invention according to claim 2 is the invention according to claim 1, wherein, as shown in FIG. 1 or 2, three or more pin holes 22 b and notches 23 a are formed, and adjacent notches 23 a When the intervals are formed at equal intervals and these intervals are defined as the first interval x, and the intervals between the adjacent pin holes 22b are formed at equal intervals and these intervals are defined as the second interval y, the second interval y Is a seed crystal holding device formed wider than the first interval x.
In the invention according to claim 2, when the body portion 24a of the uppermost seed chuck pin 24 and the uppermost notch portion 23a are brought into contact with each other, the second interval y is formed wider than the first interval x. Since the position of the pin hole 22b and the notch 23a is shifted at a certain rate as it goes downward, the notch 23a is displaced below the pin hole 22b. 24a and the notch part 23a do not contact.
[0007]
The invention according to claim 3 is the invention according to claim 1, wherein, as shown in FIG. 3, three or more pin holes 22b and notches 23a are formed, and the interval between adjacent notches 23a is respectively When the gaps are formed at equal intervals and these intervals are defined as first intervals x, and the intervals between the adjacent pin holes 22b are formed at equal intervals and these intervals are defined as second intervals y, the first intervals x and the second intervals The seed crystal holding device is formed such that the distances y are formed equally and the diameters of the body portions 24a of the plurality of seed chuck pins 24 are gradually reduced toward the lower side.
In the invention according to claim 3, when the body portion 24 a of the uppermost seed chuck pin 24 and the uppermost notch portion 23 a are brought into contact with each other, the diameter of the body portion 24 a of the seed chuck pin 24 is sequentially decreased downward. Since it is formed small, the body portion 24a of the seed chuck pin 24 other than the uppermost portion and the notch portion 23a do not contact each other.
[0008]
The invention according to claim 4 is the invention according to claim 1, wherein, as shown in FIG. 4, three or more pin holes 22 b and notches 23 a are formed, and intervals between adjacent notches 23 a are respectively set. When the gaps are formed at equal intervals and these intervals are defined as first intervals x, and the intervals between the adjacent pin holes 22b are formed at equal intervals and these intervals are defined as second intervals y, the first intervals x and the second intervals This is a seed crystal holding device in which the distance y is formed to be equal, and the plurality of cutout portions 23a are formed to increase in size in the downward direction.
In the invention according to claim 4, when the body part 24a of the uppermost seed chuck pin 24 and the uppermost notch part 23a are brought into contact with each other, the notch part 23a is formed in a larger size as it goes downward. The body 24a of the pin other than the upper part and the notch 23a do not contact each other.
[0009]
The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein, as shown in FIG. 2, the plurality of seed chuck pins 24 have the same interval as the interval between the plurality of adjacent pin holes 22b. Thus, a seed crystal holding device in which one end of the seed chuck pin 24 is integrally connected.
In the invention according to claim 5, since the seed chuck pin 24 is integrally formed, it can be inserted into the plurality of pin holes 22b at the same time, and the work of holding the seed crystal is facilitated.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
In the first embodiment of the present invention, as shown in FIG. 6, in a pulling apparatus 10 used when pulling a silicon single crystal rod from a silicon melt 12 by the CZ method, a silicon melt 12 is placed in a chamber 11. A quartz crucible 13 is provided to store the outer surface of the quartz crucible 13, and the outer surface of the quartz crucible 13 is covered with a graphite susceptor 14. The lower surface of the quartz crucible 13 is fixed to the upper end of the support shaft 16 via the graphite susceptor 14, and the lower portion of the support shaft 16 is connected to a crucible driving means (not shown). The outer peripheral surface of the quartz crucible 13 is surrounded by a heater 17 at a predetermined interval from the quartz crucible 13, and the heater 17 is surrounded by a heat insulating material 18. The high-purity polycrystalline silicon charged into the quartz crucible 13 by the heater 17 is melted into the silicon melt 12. A rotation / pull-up mechanism 19 is provided on the upper portion of the chamber 11. Above the quartz crucible 13, a seed chuck 22 is suspended from the rotation / lifting mechanism 19 via a wire cable 21, and a seed crystal 23 is attached to the seed chuck 22. The rotating / pulling mechanism 19 lowers the seed crystal 23 together with the seed chuck 22 through the wire cable 21 as shown by the solid line arrow in FIG. 6, and brings the seed crystal 23 into contact with the silicon melt 12 stored in the quartz crucible 13. .
[0011]
As shown in FIGS. 1 and 2, the seed chuck 22 has a seed crystal insertion hole 22a having a diameter capable of inserting the seed crystal 23 into the bottom of the chuck body 22d along the central axis a of the chuck body 22d. Is done. Further, the pin hole 22b is formed so as to be orthogonal to the central axis a of the chuck body 22d and offset by b with respect to the central axis a. Three pin holes 22b are formed so as not to overlap each other along the central axis a from a certain direction, and the interval between adjacent pin holes 22b is a second interval y, which is formed at equal intervals. The pin hole 22b is formed so that the cross-sectional area at the central portion of the pin hole 22b overlaps with the insertion hole 22a by about half.
[0012]
As shown by the solid line arrow in FIG. 2, the seed crystal 23 is inserted into the seed crystal insertion hole 22a. A notch 23a is formed on the side of the seed crystal 23 to be inserted into the insertion hole 22a. According to the number of pin holes 22b, three notches 23a are formed so as not to overlap each other in a certain direction. Adjacent notches 23a are spaced at a first interval x, and are formed at equal intervals. The The second interval y is provided to be wider than the first interval x. A gas discharge hole 22c for discharging the gas in the insertion hole 22a to the outside when the seed crystal 23 is inserted into the insertion hole 22a is formed to communicate with the insertion hole 22a. The seed chuck pin 24 has a shape in which three seed chuck pins are integrally connected at one end so as to fit the interval between the adjacent pin holes 22b, and the three pin holes are indicated by broken line arrows in FIG. 22b, respectively. Only the uppermost notch 23a abuts on the body 24a of the inserted seed chuck pin 24.
[0013]
In the holding device configured as described above, even if the seed crystal 23 slides down due to the stress generated when the silicon single crystal rod is pulled up and the seed crystal 23 slips down, the second notch 23a is located. And the pin body 24a come into contact with each other to hold the seed crystal 23. Furthermore, even if the second notch 23a is damaged and the seed crystal 23 slips down, the third notch 23a and the pin body 24a may contact to hold the seed crystal 23. it can.
[0014]
In the second embodiment of the present invention, as shown in FIG. 3, the first interval x is made equal to the second interval, and the diameter of the body portion 24a of the seed chuck pin 24 is sequentially reduced as it goes downward. Is done.
In the holding device configured as described above, the seed chuck pin 24 positioned below can be easily inserted into the pin hole 22b.
[0015]
In the third embodiment of the present invention, as shown in FIG. 4, the first interval x and the second interval y are made equal, and the size of the notch 23a is sequentially increased toward the lower side.
In the holding device configured as described above, the seed chuck pin 24 positioned below can be easily inserted into the pin hole 22b.
[0016]
In the above embodiment, the pin hole 22b of the seed chuck 22 and the notch 23a of the seed crystal 23 are all formed from a certain direction. However, as shown in FIG. It is not necessary to unify the directionality as indicated by broken lines c, d, and e. Thereby, when all the notches 23a are formed in a direction that is weak against the stress of the contact portion and easily breaks, there is a possibility that the damage is caused repeatedly. However, the notches 23a are formed in various directions. Can disperse the danger. Moreover, in the said embodiment, although the number of the pin hole 22b, the seed chuck pin 24, and the notch part 23a was each 3, it may be 2, 4 or 5 or more. In the second embodiment, the plurality of notches 23a have the same size. However, the top notch 23a and the pin 24 are in contact with each other, and the notches 23a are sequentially cut downward. The size of the notch 23a may be made small enough not to contact the seed chuck pin 24. As a result, even if the seed crystal is broken from the uppermost notch 23a, it can be held more stably in the next holding part. Moreover, in the said 3rd Embodiment, although the diameter of the trunk | drum 24a of a some pin is shown equally, respectively, as the uppermost notch part 23a and the pin 24 are contact | abutting, it goes to the downward direction, respectively. The diameter of the body portion 24a of the pin may be sequentially increased so as not to contact the notch portion. As a result, even if the seed crystal is broken from the uppermost notch 23a, it can be held more stably in the next holding part.
[0017]
【The invention's effect】
As described above, according to the present invention, a plurality of pin holes 22b are formed at equal intervals in the central axis direction, and a plurality of notches 23a of the seed crystal 23 are formed according to the number of pin holes 22b. Since the chuck pin 24 is inserted into each of the plurality of pin holes 22b and only the body portion 24a of the seed chuck pin inserted into the uppermost pin hole 22b is formed so as to contact the notch portion 23a, the uppermost portion of the seed crystal Even when the notch is damaged, the next notch and the body of the seed chuck pin hold the seed crystal. As a result, it is possible to reduce the incidence rate of silicon single crystal rod dropping due to seed crystal breakage.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along line AA of FIG. 2 showing a seed crystal holding device according to a first embodiment.
FIG. 2 is an exploded perspective view of the seed crystal holding device according to the first embodiment.
FIG. 3 is a cross-sectional view showing a seed crystal holding device according to a second embodiment.
FIG. 4 is a sectional view showing a seed crystal holding device according to a third embodiment.
FIG. 5 is a configuration diagram showing a notch portion of a seed crystal showing an application example of the present embodiment.
FIG. 6 is a configuration diagram of a silicon single crystal pulling apparatus including a seed crystal holding apparatus.
[Explanation of symbols]
22 Seed chuck 22a Seed crystal insertion hole 22b Pin hole 22d Chuck body 23 Seed crystal 23a Notch portion 24 Seed chuck pin 24a Pin body a Center axis x First interval y Second interval

Claims (5)

A seed crystal insertion hole (22a) formed in the bottom of the chuck body (22d) along the center axis (a) of the chuck body (22d) and perpendicular to the center axis (a) and the center axis (a) A seed chuck (22) having a pin hole (22b) formed to be biased with respect to
A seed crystal (23) having an outer diameter that can be inserted into the seed crystal insertion hole (22a) and having a notch (23a) formed on a side surface facing the pin hole (22b) in the inserted state;
In the seed crystal holding device provided with a seed chuck pin (24) that is inserted into the pin hole (22b) and the body part (24a) can come into contact with the notch part (23a),
A plurality of pin holes (22b) are formed at intervals in the direction of the central axis (a),
A plurality of the notches (23a) are formed on the side surface of the seed crystal (23) according to the number of the pin holes (22b),
The seed chuck pin (24) is inserted into each of the plurality of pin holes (22b), and only the trunk portion (24a) of the seed chuck pin (24) inserted into the uppermost pin hole (22b) is the notch portion. (23a) A seed crystal holding device configured to abut on (23a). Three or more pin holes (22b) and notches (23a) are formed, and the intervals between adjacent notches (23a) are formed at equal intervals, and these intervals are defined as the first interval (x). When the intervals of the pin holes (22b) to be formed are equally spaced and these intervals are the second interval (y),
The seed crystal holding device according to claim 1, wherein the second interval (y) is formed wider than the first interval (x). Three or more pin holes (22b) and notches (23a) are formed, and the intervals between adjacent notches (23a) are formed at equal intervals, and these intervals are defined as the first interval (x). When the intervals of the pin holes (22b) to be formed are equally spaced and these intervals are the second interval (y),
The first interval (x) and the second interval (y) are formed equal to each other, and the diameters of the body portions (24a) of the plurality of seed chuck pins (24) are sequentially formed to be smaller. Seed crystal holding device. Three or more pin holes (22b) and notches (23a) are formed, and the intervals between adjacent notches (23a) are formed at equal intervals, and these intervals are defined as the first interval (x). When the intervals of the pin holes (22b) to be formed are equally spaced and these intervals are the second interval (y),
The seed crystal holding device according to claim 1, wherein the first interval (x) and the second interval (y) are formed to be equal, and the plurality of notches (23 a) are formed to be gradually increased downward. 5. The end of the seed chuck pin (24) is integrally connected with a plurality of seed chuck pins (24) at the same interval as a plurality of adjacent pin holes (22 b). Seed crystal holding device.

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