JPH11157983A - Device for growing single crystal and growth of single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the drop of a single crystal having a large diameter and a large weight and surely and safely pull the single crystal in a depressurizied chamber. SOLUTION: A seed crystal 24a is immersed in melted Si liquid in a quartz crucible 14, and subsequently pulled up to form a neck portion 1a having a small diameter under the seed crystal 24a. A ball-like constricted part 1b is then formed under the neck portion 1a. At the time, the tips of single crystal supports 23 are opened each other so as not to bring into contact with the constricted portion 1b which is being pulled up. When the second net portion 1c under the constricted portion 1b is pulled up the waiting positions of the tips of the single crystal supports 23, the rotation of a circular member 20a is started, and rotation shafts 22 are also rotated in the clockwise direction. The tips 23a of the single crystal supports 23 are thereby closed each other to hold a portion under the constricted portion 1b. Rotational ball screw shafts 21 are simultaneously rotated to raise the single crystal supports 23 at the same speed as that of a wire 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a pulling CZ (Czoc).
The present invention relates to a single crystal growth apparatus and a single crystal growth method for producing a dislocation-free single crystal of Si (silicon) by the hralski) method.

[0002]

2. Description of the Related Art In general, in a single crystal manufacturing apparatus by the pulling CZ method, a high pressure-resistant airtight chamber is decompressed to about 10 torr and fresh Ar (argon) gas is flown, and a quartz crucible provided below the chamber is provided. The polycrystal in is melted by heating, and the seed crystal is immersed in the surface of this melt from above,
The seed crystal and the quartz crucible are rotated and moved up and down, and the seed crystal is pulled up to form a conical upper cone part whose upper end protrudes below the seed crystal, and a conical lower part whose cylindrical body part and lower end protrude. It is configured to grow a single crystal (so-called ingot) composed of a cone portion.

[0003] In addition, in order to remove dislocations generated in the seed crystal by thermal shock when the seed crystal is immersed on the surface of the melt (to eliminate dislocations), the seed crystal is deposited on the surface of the melt. A dash (Dash) method is known in which, after immersion, a neck portion having a diameter smaller than that of a seed crystal, for example, a diameter of 3 to 4 mm is formed by increasing the pulling speed relatively high, and then the pulling of the upper cone portion is started. ing.

Further, through the small diameter neck portion,
Since a single crystal having a large diameter and a large weight (150 to 200 kg or more) cannot be pulled, for example, Japanese Patent Publication No. 5-654.
As shown in Japanese Patent No. 77, after forming a small diameter neck portion by the Dash method, the pulling speed is relatively slow to form a large diameter, and then the pulling speed is relatively high to form a small diameter. A method has been proposed in which a "spherical constriction" is formed, and the constriction is gripped by a gripper to pull up a large-diameter, high-weight single crystal. Further, as a conventional device for gripping the constriction, for example, there are devices disclosed in Japanese Patent Publication No. 7-103000 and Japanese Patent Publication No. 7-515, in addition to the above publications.

[0005] Further, as another conventional example, as described in, for example, JP-A-5-270974 and JP-A-7-172981, a method of holding the body portion without forming the above-mentioned "constriction", JP-A-63-252
No. 991, JP-A-5-270975, instead of the above-mentioned “spherical constriction”, a “ring-shaped constriction” having a larger diameter than the body portion is formed between the upper cone portion and the body portion, There has been proposed a method of gripping this “ring-shaped constriction”.

[0006]

However, in the conventional gripping devices as described above, all of the conventional gripping devices have a large diameter and a large diameter in a chamber reduced to about 10 torr by a vacuum pump.
There is a problem in that a gripper for suspending a single crystal having a large weight (for example, a body part having a diameter of 400 mm and a weight of 400 kg) and a transmission mechanism of a driving source are not practical and impractical. If the single crystal is disengaged from the gripper and the single crystal falls, not only will dislocations occur and the single crystal will not become a commercial product, but the quartz crucible will be damaged and the quartz crucible will be rotated in the worst case, Cooling water inside the crucible shaft for moving up and down may react with the high-temperature melt to cause a steam explosion. The present applicant has previously disclosed a single crystal pulling apparatus for pulling a heavy single crystal as disclosed in Japanese Patent Application No. 9-931.
No. 82 proposes a structure in which the pulling chamber is divided into upper and lower parts and the upper chamber itself rotates (this proposal is not disclosed and is not a prior art to the present invention). However, since the upper chamber itself weighs several tons,
There is a problem in that the rotation mechanism is large-scale and costly.

The present invention has been made in view of the above-mentioned conventional problems and the problems of the above-mentioned apparatus of the present applicant, and has prevented a large-diameter and heavy-weight single crystal from falling in a decompressed chamber. It is an object of the present invention to provide a single crystal growth apparatus and a single crystal growth method having a function of preventing a single crystal rod from falling down, which can be pulled up safely.

[0008]

In order to achieve the above object, the present invention divides a chamber into a lower chamber and an upper chamber, and arranges a vertically movable single crystal support in the upper chamber. Means are provided for rotating the single crystal support about the single crystal pulling axis.The seed crystal is formed until the single crystal neck is formed under the seed crystal and the single crystal neck is formed under the neck. Support and raise,
Thereafter, the constriction is supported by a single crystal support structure in the upper chamber and pulled up.

That is, according to the present invention, a lower chamber in which a quartz crucible is disposed, an upper chamber disposed on the lower chamber, and a lower chamber and an upper chamber disposed on the upper chamber. A seed crystal raising / lowering mechanism that is vertically rotatably arranged to raise and lower a seed crystal, a single crystal support that is vertically movable in the upper chamber, and a unit that raises the single crystal support, Rotatable with respect to the upper chamber,
Means for rotating the single crystal support around the pulling axis of the seed crystal in the upper chamber, wherein the seed crystal raising / lowering mechanism immerses the seed crystal in the melt in the quartz crucible and pulls it up. Thereby forming a single crystal neck under the seed crystal and then forming a single crystal neck under said neck, wherein said single crystal support, said raising means and said rotating means are A single crystal growth apparatus configured to be used to pull up a single crystal by gripping the neck from below and raising the single crystal after the single crystal constriction is formed is provided.

Further, according to the present invention, a lower chamber in which a quartz crucible is disposed, an upper chamber disposed on the lower chamber, and a lower chamber and an upper chamber disposed on the upper chamber. A seed crystal raising / lowering mechanism that is vertically rotatably arranged to raise and lower a seed crystal, a single crystal support that is vertically movable in the upper chamber, and a unit that raises the single crystal support, Means for rotating the single crystal support with respect to the upper chamber, and rotating the single crystal support about a pulling axis of the seed crystal in the upper chamber. Immersing the seed crystal in the melt in the quartz crucible by the seed crystal raising / lowering mechanism to allow the seed crystal to adapt, and pulling up the seed crystal by the seed crystal raising / lowering mechanism. Forming a neck portion of the single crystal under the seed crystal, and then forming a constriction of the single crystal under the neck portion, and removing the constriction of the single crystal from below by the single crystal support. A single crystal growth method is provided, which comprises a step of gripping and a step of pulling up a neck of the seed crystal and the single crystal by the seed crystal raising / lowering mechanism and the raising means to grow a single crystal.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view schematically showing a configuration of an embodiment of a single crystal growth apparatus according to the present invention, and FIG. 2 is a perspective plan view schematically showing a configuration of an upper chamber and a single crystal holding mechanism of FIG. 3, FIG. 3 is a perspective view showing the vicinity of the single crystal support in the single crystal holding mechanism of FIGS. 1 and 2, FIG. 4 is an explanatory view showing the operation of the single crystal support of FIG. 3, and FIG. It is a perspective view of the state where a cylindrical part and a single crystal support were removed from a single crystal grasping mechanism.

In FIG. 1, a lower chamber 11 and an upper chamber 12 are arranged in a frame 10, and a drum section 13 is arranged on the frame 10. The chambers 10 to 12 and the drum unit 13 are constituted by a high-pressure-resistant vacuum vessel. Ar gas is drawn into the upper chamber 12 and discharged from the lower chamber 11. The lower chamber 11 is fixed below the frame 10, and a quartz crucible 14 for pulling the single crystal 1, a heater 16 for melting the polycrystal 15 in the quartz crucible 14, and the like are arranged in the lower chamber 11. ing. The quartz crucible 14 is supported so as to be rotatable and movable in the vertical direction.

The upper chamber 12 is constituted by a water cooling jacket system. That is, the upper chamber 12 has an upper chamber main body 12 a and a cooling unit 12 b disposed therearound, and the entire upper chamber 12 is fixed and supported on the lower chamber 11. On the upper part of the upper chamber 12, a ball bearing 27 is provided so that an annular member 20a can rotate about a single crystal pulling axis with respect to the upper chamber 12.
a. As shown in FIG. 2, the annular member 20a disposed on the upper part of the upper chamber 12 itself operates as a pulley, and is connected to the annular member rotating motor M via the belt 19 and the pulley 20b. The annular member 20a rotates. This annular member 20a
Constitutes a part of a single crystal holding mechanism 30 (see FIG. 5) described later, and rotates the single crystal holding mechanism 30 about a single crystal pulling axis.

The single crystal holding mechanism 30 has a ball bearing 2 on the bottom of the upper chamber 12 in addition to the annular member 20a.
Another annular member 2 movably arranged via 7c
0c and a cylindrical portion 20d basically connecting these two annular members 20a, 20c. That is, the annular members 20a and 20c are provided at the upper and lower ends of the hollow cylindrical portion 20d.
Has been fixed. The outer and inner circumferences of the cylindrical portion 20d are rotatably supported by the upper chamber 12 via ball bearings 27b. A vacuum seal member (not shown) is provided near the ball bearing 27b to keep the inside of the upper chamber 12 airtight.

The single crystal gripping mechanism 30 includes four sets of rotating ball screw shafts 21 as shown in FIGS.
And a rotating shaft 22 having a triangular side cross section and a single crystal support 23. The ball screw shaft 21 and the rotary shaft 22 extend vertically between the upper annular member 20a and the lower annular member 20c and in the space between the outer peripheral wall 20d1 and the inner peripheral wall 20d2 of the cylindrical portion 20d. And mounted rotatably about their axes. As shown in FIG. 3, each ball screw shaft 2
A single crystal support 23 is screwed into 1, and the single crystal support 23 can move up and down by rotation of the ball screw shaft 21. The tip 23a of the single crystal support 23 is formed in a thin shape so that the single crystal 1 can be gripped, and the single crystal support 23 has an elongated opening 23 so that the rotating shaft 22 is engaged.
b is formed. The elongated opening 23b and the rotating shaft 22 penetrating and engaging the opening 23b constitute a cam mechanism for rotating the single crystal support 23.

The single crystal support 23 is, as shown in FIG.
The rotation of the rotary ball screw shaft 21 in the direction of the arrow R2 allows it to move in the vertical direction so as to rise upward as indicated by the arrow U, and the rotation of the rotary shaft 22 in the direction of the arrow R1 causes the tip 23a to move in the direction indicated by the arrow R3. It is supported to be openable and closable so as to rotate. Rotating ball screw shaft 21, rotating shaft 22, annular member 20a, 2
0c, the single crystal support 23 constitutes the single crystal holding mechanism 30 described above. FIG. 5 shows, from the components of the single crystal gripping mechanism 30, the cylindrical portion 20d and the single crystal support 23 for convenience of illustration.
This is the state excluding. The rotating ball screw shaft 21 is rotated by a rotating ball screw shaft rotating motor (not shown) mounted inside the annular member 20a, and the rotating shaft 22 is similarly rotated by a cam shaft rotating motor (not shown) mounted inside the annular member 20a. Move. In addition, on the inner wall 20d2 of the cylindrical portion 20d,
An opening (not shown) is partially provided, and a single crystal support 2 is provided.
3 can be moved up and down within a predetermined range.

A control signal, which will be described later, is supplied from a control device 25 to the annular member rotating motor M, drum rotating motor, wire winding motor, rotating ball screw shaft rotating motor, and camshaft rotating motor. The temperature information of the quartz crucible 14 and the diameter information of the growing single crystal rod 1 are given to the controller 25 from a temperature sensor, a CCD camera, and the like (not shown).

In such a configuration, when manufacturing the single crystal 1, first, the pressure in the chambers 10 to 12 and the drum section 13 is reduced to flow Ar gas, and the polycrystal 15 in the quartz crucible 14 is heated by the heater 16. Heat to melt.
The seed crystal holder 2 attached to the tip of the wire 3
Then, the wire winding drum 4 is rotated to lower the wire 3 so that the seed crystal 24a is attached to 4 and the seed crystal 24a is immersed in the Si melt in the quartz crucible 14. At this time, the rotating shaft 22 is rotated counterclockwise as shown in FIG.
Open larger than the diameter D1 of the constriction 1b (described later)
The single crystal support 23 is waiting at a lower position.

Next, after the seed crystal 24a is immersed in the Si melt in the quartz crucible 14, the seed crystal 24a
a is pulled up at a relatively high speed so that the seed crystal 24
a small-diameter neck portion 1a having a diameter of 3 to 4 mm is formed under the upper portion a, the pulling speed is relatively reduced to form the large-diameter D1, and then the pulling speed is relatively increased. To form a ball-shaped constriction 1b.
Here, as shown in FIG. 4 (a), the tip 23a of the single crystal support 23 is in an open state so as not to contact the neck 1b being pulled up, that is, the tip 23a is in the neck 1b.
In a first position off from below. Also, during this pulling, the drum portion 13, that is, the seed crystal 24a and the quartz crucible 14 are rotating, and the quartz crucible 14 is raised so that the height of the surface of the Si melt becomes constant.

When the constriction 1b is formed, the diameter of the constricted portion 1b is larger than that of the small-diameter neck portion 1a and smaller than the diameter D2 of the constricted portion 1b so as to withstand the weight of the completed single crystal 1 (eg, 400 kg). Second neck part 1 of D2
c is formed below the constriction 1b, and then the upper cone 1d is formed by gradually lowering the pulling speed, and then the cylindrical body portion 1e is formed by pulling at a constant speed. In the pulling process so far, the single crystal 1 is supported only through the small-diameter neck portion 1a, and the limit is 100 kg or less.

Next, during pulling up of the body portion 1e by the wire 3, the second neck portion 1c under the constriction 1b is supported by the single crystal support 23 under the constriction 1b before the neck portion 1a breaks. Rises to the standby position of the tip 23a of the single crystal support 23, the rotation of the annular member 20a is started by the motor M, and FIG.
As shown in (b), the rotating shaft 22 is rotated clockwise to close the tip 23a of the single crystal support 23, that is, the tip 23a is located at the second position below the constriction 1b and is located below the constriction 1b. , And further, by rotating the rotating ball screw shaft 21, the single crystal support 23 is rotated.
Is raised at the same speed as the wire 3. In order to perform such a synchronous operation, a predetermined synchronization control signal is transmitted from the control device 25 including a computer so that the motor driving the winding drum 4 and the motor rotating the rotary ball screw shaft 21 are synchronized. give.

In this synchronous operation, since the four rotating ball screw shafts 21 rotate around the axis of the single crystal in synchronization with the drum portion 13, the single crystal 1 does not displace. That is, the control device 25 controls the motor M that rotates the annular member 20a to rotate synchronously with the motor that rotates the drum unit 13. Hereinafter, during the pulling of the body portion 1e, the single crystal 1 is supported by the single crystal support 23 (and the wire 3).
Pull up in support. Thus, the single crystal support 2
3 and its tip 23a are rotatable in a plane substantially perpendicular to the pulling direction of the single crystal 1, and when the tip 23a is in the closed position below the constriction 1b, the cam mechanism is strong. , So that the neck 1b can be securely held without dropping.

[0023]

As described above, according to the present invention, the chamber is divided into a lower chamber and an upper chamber, and a part of a single crystal gripping mechanism that can move vertically is arranged in the upper chamber. A single crystal neck is formed below the seed crystal, and the seed crystal is supported and pulled up until a single crystal constriction is formed below the neck. Thereafter, the constriction is supported by the single crystal gripping mechanism in the upper chamber. So that the large diameter in the decompressed chamber,
A heavy single crystal can be prevented from falling, and can be reliably and safely pulled. In particular, when the weight of the upper chamber itself is as large as several tons, as disclosed in the above-mentioned prior application, in the configuration in which the upper chamber itself is rotated, there is a problem that the rotation mechanism is large and the cost is high. In the present invention, the upper chamber itself is fixed, and a single crystal support that can move up and down is disposed inside the upper chamber.
, The rotation mechanism is simplified, and there is an effect that it can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is a side sectional view schematically showing a configuration of an embodiment of a single crystal growth apparatus according to the present invention.

FIG. 2 is a perspective plan view schematically showing the configuration of an upper chamber and a single crystal holding mechanism of FIG. 1;

FIG. 3 is a perspective view showing the vicinity of a single crystal support in the single crystal holding mechanism of FIGS. 1 and 2;

FIG. 4 is an explanatory view showing an operation of supporting the single crystal of FIG. 3;

FIG. 5 is a perspective view of the single crystal holding mechanism shown in FIGS. 1 and 2 with a cylindrical portion and a single crystal support removed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Single crystal 1a Neck part 1b Constriction 1c Neck part 3 Wire 4 Winding drum (wire, constitutes a seed crystal raising / lowering mechanism together with a motor not shown) 10 Frame 11 Lower chamber 12 Upper chamber 12a Upper chamber main body 12b Cooling unit 13 Drum Part 20a, 20c Annular member 20b Pulley 20d Cylindrical part 20d1 Outer peripheral wall of cylindrical part 20d2 Inner peripheral wall of cylindrical part 21 Ball screw shaft 22 Rotating shaft (constituting cam mechanism with longitudinal opening) 23 Single crystal support (rotating ball screw shaft, 23b Opening 24 Seed crystal holder 25 Control device (means for synchronizing pulling speed with each motor and means for synchronous rotation about single crystal axis) ) 30 Single crystal holding mechanism M Annular member rotation motor

Claims (11)

[Claims] 1. A lower chamber in which a quartz crucible is disposed, an upper chamber disposed above the lower chamber, and a rotatable relative to the lower chamber and the upper chamber above the upper chamber. A seed crystal raising / lowering mechanism for raising and lowering the seed crystal vertically, a single crystal support movably arranged in the upper chamber in a vertical direction, means for raising the single crystal support, Means for rotating the single crystal support around the pulling axis of the seed crystal in the upper chamber, wherein the seed crystal raising / lowering mechanism moves the seed crystal into the melt in the quartz crucible. Forming a neck portion of a single crystal below the seed crystal by dipping and pulling it up, and then forming a neck of the single crystal below the neck portion; Crystal support,
The single crystal growing apparatus, wherein the raising means and the rotating means are used to pull up the single crystal by gripping the constriction from below and raising the constriction after the constriction of the single crystal is formed. 2. The single crystal growing apparatus according to claim 1, wherein the single crystal support has a member movable between a first position deviated from below the constriction and a second position below the constriction. . 3. The single crystal growth apparatus according to claim 2, wherein said movable member is rotatable in a plane substantially perpendicular to a pulling direction of said single crystal. 4. The single crystal growth apparatus according to claim 2, wherein said single crystal support has a plurality of said movable members arranged so as to surround said constriction. 5. The single crystal growth apparatus according to claim 2, further comprising a cam mechanism for rotating said movable member. 6. The single crystal growth apparatus according to claim 1, further comprising means for synchronizing the respective pulling speeds of the seed crystal elevating mechanism and the elevating means. 7. The apparatus according to claim 1, further comprising means for synchronizing rotation of the seed crystal raising / lowering mechanism about the single crystal pulling axis with rotation about the single crystal pulling axis by the rotating means. The single crystal growth apparatus according to one of the above. 8. The upper chamber, wherein the upper chamber body has the single crystal support disposed therein, and the upper chamber is fixedly disposed with respect to the lower chamber and the upper chamber, and is disposed around the upper chamber body. The single crystal growth apparatus according to claim 1, further comprising: a cooling unit configured to cool the upper chamber body. 9. A lower chamber in which a quartz crucible is disposed, an upper chamber disposed above the lower chamber, and a rotatable relative to the lower chamber and the upper chamber above the upper chamber. A seed crystal elevating mechanism for vertically moving the seed crystal, a single crystal support movably arranged in the upper chamber in the upper chamber, a means for raising the single crystal support, Means for rotating the single crystal support around the pulling axis of the seed crystal in the upper chamber, the method comprising: Immersing the seed crystal in the melt in the quartz crucible by a mechanism to allow the seed crystal to adapt, and pulling up the seed crystal by the seed crystal lifting mechanism Forming a single crystal neck under the crystal; then forming a single crystal neck under the neck; gripping the single crystal neck from below with the single crystal support; A step of growing a single crystal by raising a neck of the seed crystal and the single crystal by the seed crystal raising / lowering mechanism and the raising means. 10. The method of growing a single crystal according to claim 9, further comprising the step of synchronizing the respective pulling speeds of the seed crystal elevating mechanism and the elevating means. 11. The single crystal growth method according to claim 9, further comprising the step of synchronously rotating the seed crystal raising / lowering mechanism and the single crystal support around a pulling axis of the single crystal.