JPH11255575A - Device for pulling single crystal and its cooling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for pulling a single crystal, capable of shortening a cooling time after the pulling of the single crystal to improve productivity. SOLUTION: This device for pulling a single crystal is obtained by disposing a cylindrical heat-insulating member comprising carbon fibers around a heater 2 for heating a quartz crucible 1 in a state brought into tight contact with the inside surface of the water-cooling chamber 4, and vertically dividing the heat-insulating member into three members 3a-3c. When it is finished to pull the single crystal 12, the charge of electricity to the heater 2 is stopped, and after the passage of some time so that the temperature of the cooling water in the cooling chamber 4 is rapidly not raised, the two upper heat-insulating members 3a and 3b are pulled with shafts 5a and 5b, respectively, top expose the inside surface of the water-cooling chamber 4. The inner wall surface of the water-cooling chamber 4 is thus brought into contact with the inner high temperature atmosphere to cool the water-cooling chamber 4.

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 pulling apparatus for producing a dislocation-free single crystal of Si (silicon) by the hralski method and a cooling method after the single crystal is pulled.

[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 with the upper end protruding below the seed crystal, and a conical lower part with a cylindrical body and lower end protruding. It is configured to grow a single crystal (so-called ingot) composed of a cone portion.

FIG. 7 shows a conventional single crystal pulling apparatus, in which a cylindrical resistance heating type heater 2 is fixed around a quartz crucible 1, and a cylindrical heat insulating member made of carbon fiber is provided around the heater 2. The material 3 is arranged in close contact with the inner wall surface of the water cooling chamber 4. When the pulling of the single crystal 12 is completed, the heater 2, the heat insulating material 3 and the like except for the quartz crucible 1 are reused. At this time, when the pulling of the single crystal 12 is completed, the inside of the water-cooling chamber is at a high temperature. It becomes unusable. Therefore, in the conventional cooling method, oxidation does not occur.
It is common to wait for the gas to cool naturally to about 00 ° C. with argon gas.

[0004]

By the way, the diameter of the water-cooling chamber 4 for growing a silicon single crystal 12 having a diameter of 400 mm is 36 inches, and the amount of the raw material is larger than that of the small diameter one. 3 is also large. The cooling time of the water-cooling chamber 4 is about 12 hours from the time when the center temperature is from several hundred degrees to about 500 ° C. at which oxidation does not occur. Dismantling, internal member 1
It takes 6-7 hours to remove ~ 3. Therefore, as the size of the apparatus increases, the cooling time becomes longer, and the time required to start the production of the next single crystal 12 becomes longer accordingly, which causes a problem that the productivity is reduced.

The present invention has been made in view of the above-described problems of the prior art, and has as its object to provide a single crystal pulling apparatus and a cooling method thereof capable of shortening a cooling time after pulling a single crystal and improving productivity. .

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a method in which a heat insulating material is divided in a vertical direction so that an inner wall surface of a water cooling chamber is exposed to a high temperature atmosphere after completion of pulling of a single crystal. The members of the heat insulating material are separated from each other.

That is, according to the present invention, there is provided a single crystal pulling apparatus having a heater for heating a single crystal in a quartz crucible, and a heat insulating material arranged around the heater so as to be in close contact with an inner wall surface of a water cooling chamber. The heat insulating material is constituted by a vertically divided plurality of members, and one or more of the heat insulating materials such that a part of the inner wall surface of the water cooling chamber is exposed to an internal atmosphere after completion of pulling of the single crystal. A single crystal pulling apparatus is provided, wherein the members are moved upward or downward so that the members can be separated from each other.

According to the present invention, there is provided a single crystal pulling apparatus having a heater for heating a single crystal in a quartz crucible, and a heat insulating material arranged around the heater so as to be in close contact with an inner wall surface of a water cooling chamber. The heat insulating material is constituted by a member divided into a plurality of pieces in a circumferential direction, and one or more of the heat insulating materials is so formed that a part of an inner wall surface of the water cooling chamber is exposed to an internal atmosphere after completion of pulling of a single crystal. A single crystal pulling apparatus is provided, wherein the members are moved along the circumference of the chamber so that the members can be separated from each other.

According to the present invention, the heater is arranged so as to be in close contact with the inner wall surface of the water-cooling chamber around the heater for heating the single crystal in the quartz crucible, and is divided vertically and / or circumferentially. After the pulling of the single crystal of at least one of the plurality of heat insulating members, the inner wall surface of the water cooling chamber is moved upward or downward and / or circumferentially so that the inner wall surface of the water cooling chamber is exposed to the internal atmosphere. A method for cooling a single crystal pulling apparatus configured to allow members to be separated from each other, wherein a distance between members of the heat insulating material is changed such that different portions of an inner wall surface of the chamber are sequentially exposed to the atmosphere. And a method for cooling a single crystal pulling apparatus having:

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view showing an embodiment of the single crystal pulling apparatus according to the present invention, FIG. 2 is a cross-sectional view showing a cooling state of the single crystal pulling apparatus of FIG. 1, and FIG. 3 is a single crystal pulling apparatus of FIG. It is explanatory drawing which shows the cooling time of an example.

FIG. 1B shows a side view of the single crystal pulling apparatus, and FIG. 1A shows a horizontal cross-sectional view along the line AA in FIG. 1B. A cylindrical resistance heating type heater 2 is fixed around the quartz crucible 1, and a cylindrical heat insulating material 3 made of carbon fiber is arranged around the heater 2 in close contact with the inner wall surface of the water cooling chamber 4. ing. And the heat insulating material 3 is vertically divided into three members 3a to 3c,
The lowermost heat insulating member 3c is fixed. The upper two heat insulating members 3a, 3b are respectively supported by a pair of shafts 5a, 5b so as to be movable in the vertical direction, and the shafts 5a, 5b are exposed to the outside from above the water cooling chamber 4. The shafts 5a and 5b are made of carbon, and have one end connected to a heat insulating member to be moved and the other end protruding outside the water cooling chamber 4. Although not shown, a cooling pipe through which cooling water flows is wound around the outer surface of the water cooling chamber 4 in a coil shape.

An upper chamber 10 is connected to the water cooling chamber 4, and a single crystal pulling wire 11 is suspended from the upper chamber 10. Then, the seed crystal attached to the tip of the wire 11 is melted in a state where the inside of the water cooling chamber 4 and the upper chamber 10 is maintained at a low pressure and the single crystal raw material of the quartz crucible 1 is heated and melted by the heater 2. The single crystal 12 is grown under the seed crystal by immersing the seed crystal from above and pulling up the seed crystal while rotating and moving the seed crystal and the quartz crucible 1 up and down.

When the pulling of the single crystal 12 is completed,
After a certain period of time has elapsed so that the temperature of the cooling water in the water-cooling chamber 4 does not rise sharply, the upper surface of the water-cooling chamber 4 is exposed as shown in FIG. Are lifted by the shafts 5a and 5b, respectively. Therefore, since the inner wall surface of the water cooling chamber 4 comes into contact with the high temperature atmosphere inside, the inside of the water cooling chamber 4 is cooled.

The solid line in FIG. 3 shows the temperature change of the conventional example due to natural cooling. The time from when the power supply to the heater 2 is stopped to when the temperature in the water cooling chamber 4 drops to about 500 ° C. at which oxidation does not occur is approximately about 500 ° C. 11 hours. On the other hand, the broken line in FIG. 3 indicates that after the power supply to the heater 2 is stopped, the heat insulating members 3a and 3b are pulled up to separate the heat insulating members 3a and 3b from the heat insulating members 3b and 3c as shown in FIG. However, it shows a temperature change when this separation state is continued, and the time until the temperature drops to about 500 ° C. is about 7 hours.

After the power supply to the dotted heater 2 in FIG. 3 is stopped, as shown in FIG.
b and the space between the heat insulating members 3a and 3b and the heat insulating member 3
b, 3c are separated, and this separated state is continued for 30 minutes,
Thereafter, as shown in FIG. 1, the heat insulating members 3a and 3b are lowered and the heat insulating members 3a to 3c are brought into close contact with each other, and this state is continued for 30 minutes.
The time until the temperature dropped to about 0 ° C. was about 6 hours.

In the above-described embodiment, the upper two heat insulating members 3a and 3b are configured to be pulled up from above by the shafts 5a and 5b, respectively. However, as shown in FIG. You may make it push up from. Further, as shown in FIG. 5, the upper heat insulating member 3a may be pulled up from above, and the intermediate heat insulating member 3b may be pushed up from below. Further, as shown in FIG. 6, the heat insulating members 3a and 3b may be supported in the horizontal direction and pushed up or pulled up. Although not shown, instead of dividing the heat insulating member 3 vertically,
The water cooling chamber 4 may be rotatable so as to be divided in the circumferential direction so that the inner wall surface of the water cooling chamber 4 is exposed. In this case, the rotating trajectory is not a complete circular trajectory, so that a part of the rotating heat insulating member at least partially overlaps the other heat insulating members.
The orbit should be such that adjacent heat insulating members can be avoided. Further, at least one or more of the heat insulating members divided in the circumferential direction may be divided in the vertical direction as in the above embodiment, and may be movable in the circumferential direction and in the vertical direction.

The one or more heat-insulating members movable vertically and / or circumferentially are provided between the members of the heat-insulating material so that different portions of the inner wall surface of the water-cooling chamber 4 are sequentially exposed to the atmosphere. Is preferably changed. In order to change the distance between the members of the heat insulating material, for example, a step of separating the members of the heat insulating material and a step of bringing the members close to each other can be alternately repeated. Further, the temperature of the cooling water in the water cooling chamber 4 is detected at a plurality of locations, and the detected temperatures of the cooling water at the plurality of locations are supplied to a control device (not shown). It is also possible to provide a driving device for controlling so that is automatically changed. That is, a motor for raising and lowering the shafts 5a and 5b and the like in the above-described embodiment, and a rack and pinion mechanism for raising and lowering the shafts 5a and 5b by its rotational force can be provided. When there are a plurality of movable heat insulating materials, the control device may include a heat insulating material to be moved according to the detected cooling water temperatures at a plurality of locations and a CPU (central processing unit) for determining a moving direction. (Processing device) to control the motor.

[0018]

As described above, according to the present invention, the inner wall surface of the water-cooling chamber is exposed to the high temperature atmosphere after the heat insulating material is divided vertically and / or circumferentially and the single crystal is pulled up. Since the members of the heat insulating material are separated from each other, the cooling time after pulling up the single crystal can be shortened, and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a single crystal pulling apparatus according to the present invention.

FIG. 2 is a sectional view showing a cooling state of the single crystal pulling apparatus of FIG.

FIG. 3 is an explanatory view showing a cooling time of the single crystal pulling apparatus of FIG. 1 and a conventional example.

FIG. 4 is a cross-sectional view illustrating a single crystal pulling apparatus according to a second embodiment.

FIG. 5 is a sectional view showing a single crystal pulling apparatus according to a third embodiment.

FIG. 6 is a sectional view showing a single crystal pulling apparatus according to a fourth embodiment.

FIG. 7 is a sectional view showing a conventional single crystal pulling apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz crucible 2 Heater 3 Heat insulating material 3a-3c Heat insulating member 4 Water cooling chamber 5a, 5b Shaft

Claims (9)

[Claims] 1. A single crystal pulling apparatus comprising: a heater for heating a single crystal in a quartz crucible; and a heat insulating material arranged around the heater so as to be in close contact with an inner wall surface of a water cooling chamber. One or more members of the heat insulating material so that a part of the inner wall surface of the water cooling chamber is exposed to the internal atmosphere after completion of pulling of the single crystal. A single crystal pulling apparatus characterized in that it is configured to be movable in a direction so that members can be separated from each other. 2. The unit according to claim 1, wherein said members are three or more heat insulating members located in a vertical direction, and members in an upper stage and a lower stage are movable upward. Crystal pulling device. 3. One end is connected to a member to be moved, and the other end protrudes out of the water cooling chamber in order to move one or more of the vertically divided members upward or downward. The single crystal pulling apparatus according to claim 1, wherein the single crystal pulling apparatus has a shaft that is bent. 4. A single crystal pulling apparatus comprising: a heater for heating a single crystal in a quartz crucible; and a heat insulating material disposed around the heater so as to be in close contact with an inner wall surface of a water cooling chamber, wherein the heat insulating material is circular. One or more members of the heat insulating material are formed of a plurality of members that are divided into a plurality of members in the circumferential direction. A single crystal pulling apparatus characterized in that each member is moved along the circumference so as to be separated from each other. 5. At least one of the members divided into a plurality in the circumferential direction is further divided in the up-down direction, and one or more members of the heat insulating material are moved upward or downward to separate each member. 5. The device according to claim 4, wherein the components are configured to be separated from each other.
The single crystal pulling apparatus as described in the above. 6. One end is connected to a member to be moved, and the other end of the water-cooled chamber is moved to move one or more of the horizontally divided members along the circumference of the chamber. The single crystal pulling apparatus according to claim 4, further comprising a shaft protruding outside. 7. A plurality of heat insulating materials arranged around a heater for heating a single crystal in a quartz crucible so as to be in close contact with an inner wall surface of a water cooling chamber and divided vertically and / or circumferentially. At least one of the members can be moved upward or downward and / or circumferentially so that the inner wall surface of the water-cooling chamber is exposed to the internal atmosphere after the single crystal has been pulled up, so that the members can be separated from each other. A method for cooling a single crystal pulling apparatus, comprising: changing a distance between members of the heat insulating material so that different portions of an inner wall surface of the chamber are sequentially exposed to the atmosphere. How to cool the device. 8. The method according to claim 7, wherein the step of changing the distance between the members of the heat insulating material alternates the step of separating the members of the heat insulating material from each other and the step of bringing the members close to each other. A method for cooling a single crystal pulling apparatus as described in the above. 9. The method according to claim 9, further comprising the step of detecting the temperature of the cooling water in the chamber at a plurality of locations, and controlling the distance between the members of the heat insulating material in accordance with the detected temperatures of the cooling water at the plurality of locations. And, when there are a plurality of movable members of the heat insulating material, a step of controlling the movement by determining the moving direction of the heat insulating material and the moving direction according to the detected coolant temperature at the plurality of locations. The method for cooling a single crystal pulling apparatus according to claim 7 or 8, wherein