JP2000143388A - Temperature measuring system of single crystal rod in pulling up apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a single crystal rod hardly scattering the quality in good reproducibility by monitoring temperature distribution in the vicinity of solid-liquid interface of the single crystal rod and controlling the variation in the temperature distribution. SOLUTION: A melt 12 of a material which becomes a single crystal rod 15 is stored in a crucible 13 disposed in a chamber 11 of a pulling up apparatus 10 and the melt 12 is heated by a heater 17 surrounding the outer peripheral surface of the crucible 13 and further, the single crystal rod 15 is pulled up from the melt 15. A rod 23 having high radiation ratio is disposed parallel to pulling up shaft of the single crystal rod 15 and the lower end of the rod 23 is brought into contact with the melt 12. Further, the temperature distribution in the longitudinal direction is detected by a non-contact type temperature sensor 24 set outside the chamber 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for pulling and growing a single crystal rod such as a silicon single crystal rod. More specifically, the present invention relates to a system for measuring the temperature of a single crystal rod in a pulling device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a silicon melt 2 is stored in a quartz crucible 3 provided in a chamber 1, and a heater 7 surrounding the outer peripheral surface of the quartz crucible 3 applies the silicon melt 2. A pulling device 4 configured to heat and further pull a silicon single crystal rod 5 from the silicon melt 2
It has been known. In this device 4, a silicon single crystal rod 5
A heat shielding member 6 is inserted between the outer peripheral surface of the silicon crucible 3 and the inner peripheral surface of the quartz crucible 3 so as to surround the silicon single crystal rod 5. A window 1c in which a transparent quartz plate 1b is inserted is formed in a shoulder 1a of the chamber 1, and a chamber 1 is provided outside the window 1c.
A non-contact type temperature sensor 8 facing the inside is installed. In order to measure the temperature distribution on the outer peripheral surface of the silicon single crystal rod 5 being pulled by the pulling device 4, the radiant heat generated from the outer peripheral surface of the silicon single crystal rod 5 being pulled is directly captured by the temperature sensor 8, The temperature distribution in the longitudinal direction of the silicon single crystal rod 5 is measured.

[0003]

However, the conventional method for measuring the temperature of a silicon single crystal rod has a drawback in that the temperature distribution cannot be measured accurately if irregularities are present on the outer peripheral surface of the single crystal rod. Was. Further, since the outer peripheral surface of the glossy silicon single crystal rod reflects stray light, that is, light mainly from the heater, it has been difficult to measure only the radiant heat from the silicon single crystal rod with high accuracy. An object of the present invention is to monitor a temperature distribution in the vicinity of a solid-liquid interface of a single crystal rod and suppress the fluctuation, thereby enabling a single crystal rod with less variation in quality to be manufactured with good reproducibility and efficiency. An object of the present invention is to provide a temperature measurement system for a single crystal rod in a pulling device. Another object of the present invention is to provide a single crystal rod in a pulling apparatus which is hardly affected by stray light emitted from a heater or the like and reflected by the single crystal rod, and which can avoid mixing of carbon into the melt. It is to provide a temperature measurement system. Still another object of the present invention is to measure the temperature of a single crystal rod in a pulling device, which hardly affects the atmosphere in the chamber and can relatively easily set a high emissivity rod in the chamber. It is to provide a system.

[0004]

The invention according to claim 1 is
As shown in FIG. 1, a melt 12 of a material to be a single crystal rod 15 is stored in a crucible 13 provided in a chamber 11,
This is an improvement of the pulling device configured so that the heater 17 surrounding the outer peripheral surface of the crucible 13 heats the melt 12 and the single crystal rod 15 is pulled from the melt 12. Its characteristic configuration is that it is provided near the outer peripheral surface of the single crystal rod 15 in parallel with the pulling axis of the single crystal rod 15 and the lower end is
And a non-contact type temperature sensor 24 provided outside the chamber 11 for detecting a temperature distribution in the longitudinal direction of the bar 23.

In the temperature measuring system for a single crystal rod according to the present invention, the lower end of the rod 23 having a high emissivity is connected to the melt 12.
, It is possible to imitate the heat conduction at the solid-liquid interface of the single crystal rod 15. Therefore, the temperature distribution of the rod 23 approaches the temperature distribution in the longitudinal direction (pulling direction) of the single crystal rod 15 being pulled. That is, by monitoring the change in the temperature distribution of the rod 23 with the temperature sensor 24, the change in the temperature distribution of the single crystal rod 15 can be accurately estimated.

The invention according to claim 2 is the invention according to claim 1, and further includes a rod 23 having a high emissivity as shown in FIG.
A rod body 23a formed of graphite, and a rod body 23a
And a chip 23b made of high-purity quartz, which is attached to the lower end of the base material and is in contact with the melt 12. In the temperature measuring system for a single crystal rod according to the second aspect, since the rod main body 23a is formed of graphite having a high emissivity, the influence of stray light emitted from the heater 17 or the like and reflected by the single crystal rod 15 is almost eliminated. I do not receive. A chip 2 that contacts the melt 12
Since 3b is formed of high-purity quartz, it is possible to avoid mixing of carbon into the melt 12.

A third aspect of the present invention is the invention according to the first or second aspect, wherein the high emissivity rod 23 surrounds the outer peripheral surface of the single crystal rod 15 as shown in FIG. Member 2
2 is attached via a stay 26. In the temperature measurement system for a single crystal rod according to the third aspect, the rod 23 having a high emissivity is relatively easily applied to the chamber 11 without substantially affecting the atmosphere in the chamber 11.
It can be installed inside.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. As shown in FIGS. 1 and 2, a quartz crucible 13 for storing a silicon melt 12 is provided in a chamber 11 of a pulling device 10 for pulling a silicon single crystal rod 15, and the outer surface of the quartz crucible 13 is a graphite susceptor 14. Coated. 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 crucible driving means (not shown) (FIG. 1). Although the crucible driving means is not shown, the quartz crucible 1
3 has a first rotation motor for rotating 3 and a lifting / lowering motor for raising / lowering the quartz crucible 13, and these motors can rotate the quartz crucible 13 in a predetermined direction,
It can be moved up and down. The outer peripheral surface of the quartz crucible 13 is spaced apart from the quartz crucible 13 by a predetermined distance.
7 and the outer peripheral surface of the heater 17 is the heater 1
At a predetermined interval from 7, it is surrounded by a heat retaining cylinder 18. The heater 17 heats and melts the high-purity polycrystalline silicon charged into the quartz crucible 13 to form the silicon melt 12.

A cylindrical casing 19 is connected to the upper end of the chamber 11. The casing 19 is provided with a pulling means 21. The pulling means 21 includes a pulling head (not shown) rotatably provided at the upper end of the casing 19 in a horizontal state, a second rotation motor (not shown) for rotating the head, and a quartz crucible 13 from the head.
Wire cable 21a hanging down toward the center of rotation
And a pulling motor (not shown) provided in the head for winding or feeding the wire cable 21a. A silicon melt 12 is provided at the lower end of the wire cable 21a.
A seed crystal 21b for mounting the silicon single crystal rod 15 by immersion in the substrate is attached.

A heat shielding member 22 surrounding the outer peripheral surface of the silicon single crystal rod 15 is provided between the outer peripheral surface of the silicon single crystal rod 15 and the inner peripheral surface of the quartz crucible 13 (FIGS. 1 and 2). . The heat shielding member 22 is formed in a cylindrical shape and blocks a cylindrical portion 22a (FIG. 1) that blocks radiant heat from the heater 17, and a cone portion 22b (see FIG. 1) connected to the lower edge of the cylindrical portion 22a and having a diameter decreasing downward. 1 and FIG. 2) and the tubular portion 22
and a flange portion 22c (FIG. 1), which is connected to the upper edge of a and protrudes outward in a substantially horizontal direction. The flange portion 22c
Is placed on the heat retaining tube 18 so that the cone portion 22b
The heat shield member 22 is fixed in the chamber 11 such that the lower edge of the heat shield member is located above the surface of the silicon melt 12 by a predetermined distance (FIG. 1). The heat shielding member 22 is formed of graphite.

The present embodiment is characterized in that the silicon single crystal rod 15 is disposed near the outer peripheral surface of the silicon single crystal rod 15.
And a non-contact type temperature sensor 24 which is provided outside the chamber 11 and detects a temperature distribution in the longitudinal direction of the bar 23 provided in parallel with the pulling shaft of 1 and 2). The lower end of the rod 23 comes into contact with the silicon melt 12 and has a rod body 23a and a tip 23b attached to the lower end of the rod body 23a.
The rod body 23a is formed of a material having a high emissivity, for example, graphite, SiC or the like, but is preferably formed of graphite. The tip 23b is configured to be in contact with the silicon melt 12, and is preferably formed of high-purity quartz. The outer diameter of the rod body 23a and the tip 23b is 4
~ 12mm, preferably formed in a small diameter of about 8mm,
The tip 23b is screwed to the lower end of the rod body 23a in this embodiment. The rod body 23a was formed of a material having a high emissivity in order to avoid the influence of stray light from the heater 17 and the like. The chip 23b was formed of high-purity quartz because carbon was mixed into the silicon melt 12. To avoid.

A window 11c into which a transparent quartz plate 11b is inserted is formed in a shoulder 11a of the chamber 11, and the temperature sensor 24 is installed outside the window 11c so as to face the inside of the chamber 11 (see FIG. 1). 1). In this embodiment, the temperature sensor 24 is a CCD (Charge Coupled Device) sensor. Further, the rod 23 is a heat shielding member 22.
(See FIGS. 1 and 2). The stay 26 is formed in a thin frame shape of a substantially right triangle. As shown in detail in FIG. 2, the rod 23 is attached to the stay 26 by a bolt 27 and a nut 28 in parallel with the oblique side 26a and at a predetermined interval from the oblique side 26a, and the stay 26 connects the short side 26b to the bolt 29. By being fixed to the upper surface of the cone portion 22b, it is attached to the heat shielding member 22. By forming the stay 26 as described above, the bar 23 having a high emissivity is relatively easily applied to the chamber 1 without substantially affecting the atmosphere in the chamber 11.
1 can be installed.

On the other hand, the chamber 11
Gas supply / discharge means (not shown) for supplying an inert gas to the silicon single crystal rod side and discharging the inert gas from the inner peripheral surface side of the crucible of the chamber 11 is connected. A rotary encoder (not shown) is provided on an output shaft (not shown) of the pulling motor, and a weight sensor (not shown) for detecting the weight of the silicon melt 12 in the quartz crucible 13 is provided on the crucible driving means. ), And a linear encoder (not shown) for detecting the elevation position of the support shaft 16. Each detection output of the rotary encoder, the weight sensor and the linear encoder is connected to a control input of a controller (not shown),
The control output of the controller is connected to a pulling motor of the pulling means 21 and a lifting motor of the crucible driving means, respectively. Further, the controller is provided with a memory (not shown), in which the winding length of the wire cable 21a with respect to the detection output of the rotary encoder, that is, the pulling length of the silicon single crystal rod 15 is stored as a first map. The liquid level of the silicon melt 12 in the quartz crucible 13 with respect to the detection output of the weight sensor is stored as a second map. The controller is configured to control the motor for raising and lowering the crucible driving means so as to always keep the liquid level of the silicon melt 12 in the quartz crucible 13 at a constant level based on the detection output of the weight sensor.

The silicon single crystal rod 1 constructed as described above
The operation of the temperature measurement system 5 will be described. By placing a small-diameter high-emissivity rod 23 near the outer peripheral surface of the silicon single crystal rod 15 being pulled, and bringing the lower end of this rod 23, that is, a high-purity quartz chip 23b into contact with the silicon melt 12, The heat conduction at the solid-liquid interface of the silicon single crystal rod 15 can be simulated. For this reason, the temperature distribution of the rod 23 has a longitudinal direction (pulling direction) of the silicon single crystal rod 15 being pulled.
Approaching the temperature distribution. Therefore, by detecting the radiant heat generated from the outer peripheral surface of the rod 23 with the temperature sensor 24, the temperature distribution in the longitudinal direction of the rod 23 can be measured, and the change in the temperature distribution of the rod 23 can be monitored. By
A change in the temperature distribution of the silicon single crystal rod 15 can be accurately estimated. As a result, when the measured temperature distribution of the bar 23 is deviated from the predetermined temperature distribution,
By adjusting the position of the quartz crucible 13 and the shape of the heat retaining cylinder 18, or by adjusting the pulling speed of the silicon single crystal rod 15, the temperature distribution is restored and the fluctuation of the temperature distribution is suppressed. As a result, the silicon single crystal rod 15 with less variation in quality can be manufactured with good reproducibility and efficiency. In the above embodiment, a silicon single crystal rod is described as a single crystal rod, but a single crystal rod such as germanium or gallium arsenide may be used.

[0015]

As described above, according to the present invention, a rod having a high emissivity is provided near the outer peripheral surface of a single crystal rod in a pulling apparatus in parallel with the pulling axis of the single crystal rod. The lower end is brought into contact with the melt, and a non-contact type temperature sensor provided outside the chamber is configured to detect the temperature distribution in the longitudinal direction of the rod. The contact can simulate the heat conduction at the solid-liquid interface of the single crystal rod. Therefore, the temperature distribution of the rod approaches the temperature distribution in the longitudinal direction of the single crystal rod being pulled. That is, if the change in the temperature distribution of the rod is monitored by the temperature sensor, the change in the temperature distribution of the single crystal rod can be accurately estimated. As a result, if the temperature distribution of the rod deviates from a predetermined temperature distribution, it is possible to suppress the fluctuation of the temperature distribution by adjusting the crucible position or the like or adjusting the pulling speed of the single crystal rod. As a result, a single crystal rod with less variation in quality can be manufactured with good reproducibility and efficiency.

Further, if the rod body of the rod having a high emissivity is formed of graphite and the high-purity quartz chip attached to the lower end of the rod body is configured to come into contact with the melt, the rod is emitted from a heater or the like. It is hardly affected by the stray light reflected by the single crystal rod, and can prevent carbon from being mixed into the melt. Furthermore, if a rod with a high emissivity is attached to a heat shielding member surrounding the outer peripheral surface of the single crystal rod via a stay, it hardly affects the atmosphere in the chamber, and the rod with a high emissivity can be relatively easily formed. It can be installed in the chamber.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram showing a silicon single crystal rod pulling apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of a pulling device including a rod having a high emissivity.

FIG. 3 is a sectional view showing a conventional example and corresponding to FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 Pulling device 11 Chamber 12 Silicon melt 13 Quartz crucible 15 Silicon single crystal rod 17 Heater 22 Heat shielding member 23 High emissivity rod 23a Rod body 23b Chip 26 Stay

Claims (3)

[Claims] 1. A crucible (13) provided in a chamber (11).
A melt (12) of a material to be a single crystal rod (15) is stored therein, and a heater (17) surrounding the outer peripheral surface of the crucible (13) is
2) is heated, and in a pulling device configured to pull up the single crystal rod (15) from the melt (12), the single crystal rod (15) is provided near the outer peripheral surface of the single crystal rod (15). A high-emissivity rod (23) provided parallel to the pulling axis and having a lower end in contact with the melt (12), and a temperature distribution in the longitudinal direction of the rod (23) provided outside the chamber (11). A non-contact temperature sensor (24) for detecting a temperature of a single crystal rod. 2. A rod body (23a) having a high emissivity rod made of graphite, and a high-purity quartz rod attached to a lower end of the rod body (23a) and in contact with a melt (12). The single crystal rod temperature measuring system according to claim 1, further comprising a tip (23b). 3. The high emissivity rod (23) is attached via a stay (26) to a heat shielding member (22) surrounding the outer peripheral surface of the single crystal rod (15). Single crystal rod temperature measurement system.