JP3726866B2 - Head structure of silicon single crystal pulling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the structure of a head of an apparatus for pulling up a silicon single crystal rod.
[0002]
[Prior art]
Conventionally, a wire for pulling up a single crystal rod is wound up by a wire take-up drum, and this drum rotates around the axis of the single crystal rod, and the winding direction is symmetric on the left and right along the pulling rotation axis of this drum. A pair of spiral grooves are provided on the peripheral wall of the drum, and a pair of wire members are suspended so that these grooves are guided in the same winding direction. Further, seed crystals are formed at the lower ends of these wire members. A wire winding mechanism to which a holding body is connected is disclosed (Japanese Patent Laid-Open No. 9-156887).
In the wire winding mechanism configured as described above, since the load is evenly distributed to the pair of wire members, the burden on the wire members is reduced, and a thin and flexible wire member having flexible elasticity can be used. The winding operation of the wire member is also smooth. As a result, the wire winding drum can be reduced in diameter and size, and the entire apparatus can be reduced in size and weight.
[0003]
[Problems to be solved by the invention]
However, in the conventional wire winding mechanism disclosed in Japanese Patent Laid-Open No. 9-156877, a wire winding drum is rotatably accommodated in a vacuum head chamber via a bearing, and the head chamber is placed in the main chamber. Because of the communication, dust generated by friction between the drum and the wire member and dust generated in the bearing may enter the main chamber from the wire through-hole communicating with both chambers.
An object of the present invention is to provide a head structure of a silicon single crystal pulling apparatus that can prevent dust generated from a sliding portion of a wire in the head chamber from entering the main chamber.
[0004]
[Means for Solving the Problems]
As shown in FIG. 1, the invention according to claim 1 includes a wire 13 that is pulled up while rotating a silicon single crystal rod 11 from a silicon melt in a main chamber 12, and a wire winding that is wound while rotating the wire 13. This is an improvement of the silicon single crystal pulling apparatus including the mechanism 14 and the head chamber 16 that houses the wire winding mechanism 14 and communicates with the main chamber 12.
The characteristic configuration is that the suction port 33a of the head vacuum pump 33 is connected to the head chamber 16 so that the head vacuum pump 33 sucks and discharges dust generated in the head chamber 16, and is used for the head. The discharge port 33 b of the vacuum pump 33 is connected to the head chamber 16 via the filter 34, and the dust generated in the head chamber 16 is configured to be collected by the filter 34 .
In the head structure of the silicon single crystal pulling apparatus according to the first aspect, when the wire winding mechanism 14 is operated, the wire 13 or the like is rubbed or slid in the head chamber 16 to generate dust. However, these dusts are sucked together with the gas in the head chamber 16 by the head vacuum pump 33 and discharged out of the head chamber 16.
[0005]
When the gas in the head chamber 16 is sucked together with dust by the head vacuum pump 33, the dust in the gas is collected by the filter 34. Further, the gas purified by removing dust returns to the head chamber 16 again.
[0006]
The invention according to claim 2 is the invention according to claim 1 , and further, as shown in FIG. 1, provided in the first conduit 41 connecting the suction port 33 a of the head vacuum pump 33 and the head chamber 16. The first opening / closing valve 51 for opening and closing the first pipe 41, the discharge port 33b of the head vacuum pump 33 provided in the second pipe 42 connecting the discharge port 33b of the head vacuum pump 33 and the filter 34. A switching valve 36 that switches the filter 34 or the atmosphere to communicate with the atmosphere, a second opening / closing valve 52 that is provided in a third pipeline 43 that connects the filter 34 and the head chamber 16, and opens and closes the third pipeline 43. A controller for controlling the head vacuum pump 33, the first on-off valve 51, the switching valve 36, and the second on-off valve 52 according to the operating state of the pulling device 10 is provided.
[0007]
In the head structure of the silicon single crystal pulling apparatus according to claim 2 , when the inside of the main chamber 12 is opened to the atmosphere, the controller opens the first and second on-off valves 51 and 52, and the switching valve 36 is moved to the head. The discharge port 33 b of the vacuum pump 33 and the filter 34 are switched to communicate with each other, and dust generated in the head chamber 16 is collected by the filter 34.
When the inside of the main chamber 12 is set to a predetermined negative pressure, the controller opens the first on-off valve 51, closes the second on-off valve 52, and connects the switching valve 36 to the discharge port 33b of the head vacuum pump 33 and the atmosphere. The dust generated in the head chamber 16 is discharged into the atmosphere.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the silicon single crystal rod 11 is pulled up from the silicon melt by the pulling device 10. The pulling device 10 includes a wire 13 that pulls up the silicon single crystal rod 11 from the silicon melt in the main chamber 12, a wire winding mechanism 14 that winds the wire 13 while rotating, and a wire winding mechanism 14. And a head chamber 16 that accommodates and communicates with the main chamber 12.
[0009]
The head chamber 16 is rotatably provided at the upper end of the main chamber 12. That is, a first cylindrical portion 12a into which the wire 13 can be loosely inserted is protruded upward on the upper surface of the main chamber 12, and a second cylindrical portion 16a into which the wire 13 can be loosely inserted is formed on the lower surface of the head chamber 16. It protrudes toward. The second cylinder part 16a is formed to have a larger diameter than the first cylinder part 12a, and is fitted into the first cylinder part 12a via the magnetic fluid seal 17 so as to be rotatable. The magnetic fluid seal 17 is configured to block the inside of the main chamber 12 and the head chamber 16 from the atmosphere by closing the gap between the first cylinder portion 12a and the second cylinder portion 16a. A driven pulley 18 is fitted on the outer peripheral surface of the second cylindrical portion 16a, and a belt is provided between the pulley 18 and a driving pulley (not shown) fitted to an output shaft of a head driving motor (not shown). 19 is passed. The head chamber 16 is configured to be rotationally driven by the head driving motor.
[0010]
The wire winding mechanism 14 includes a fixed pulley 21 suspended from the lower surface of the upper wall 16b of the head chamber 16, a winding drum 22 rotatably and slidably attached to the upper surface of the lower wall 16c of the head chamber 16, and A drum driving motor 23 for rotating the winding drum 22; The winding drum 22 is splined to the shaft 24. That is, the drum 22 is configured to be slidable in the longitudinal direction of the shaft 24 and not rotatable relative to the shaft 24. The reason why the drum 22 is slidably fitted onto the shaft 24 is to wind the wire 13 around the drum 22 uniformly. The shaft 24 is rotatably supported by a pair of brackets 26 and 26 erected on the upper surface of the lower wall 16c of the head chamber 16 via bearings 27 and 27 (FIG. 2).
[0011]
The drum driving motor 23 is an electric motor with a speed reducer, and is attached to the upper surface of the upper wall 16b of the head chamber 16. The output shaft 23a of the motor 23 is inserted into the head chamber 16 from the upper wall 16b, and a drive gear 28 (FIG. 2) is fitted to the lower end thereof. One end of the shaft 24 extends to the vicinity of the output shaft 23a, and a driven gear 29 (FIG. 2) that meshes with the drive gear 28 is fitted to one end of the shaft 24. In this embodiment, a bevel gear is used as the drive gear 28 and the driven gear 29. A worm may be used as the drive gear 28 and a worm wheel may be used as the driven gear 29. The wire 13 is wound around the drum 22 so as to be able to be fed, and the fed wire 13 is engaged with the fixed pulley 21 and then passes through the second cylindrical portion 16a and the first cylindrical portion 12a and hangs down into the main chamber 12. Is done. A chuck 32 for holding the seed crystal 31 is attached to the tip of the wire 13 (FIG. 1). Reference numeral 30 in FIG. 2 denotes a magnetic fluid seal.
[0012]
On the other hand, a head vacuum pump 33 is attached to the upper surface of the upper wall 16b of the head chamber 16, as shown in detail in FIG. One end of the first conduit 41 is connected to the suction port 33 a of the pump 33, and the other end of the first conduit 41 is inserted into the head chamber 16 from the side wall 16 d of the head chamber 16. The discharge port 33 b of the pump 33 is connected to the inlet 34 a of the filter 34 via the second pipe 42. One end of the third conduit 43 is connected to the outlet 34 b of the filter 34, and the other end of the third conduit 43 is inserted into the head chamber 16 from the side wall 16 d of the head chamber 16.
[0013]
The first and third pipes 41 and 43 are provided with first and second on-off valves 51 and 52 for opening and closing the pipes 41 and 43, respectively, and the second pipe 42 is provided with a head vacuum pump 33. A switching valve 36 for switching the discharge port 33b so as to communicate with the filter 34 or the atmosphere is provided. The first and second on-off valves 51 and 52 are two-port and two-position switching solenoid valves. When turned on, the first and third pipelines 41 and 43 are opened, and when turned off, the first and third pipelines 41 and 43 are opened. 43 is configured to be closed. The switching valve 36 is a three-port 2-position switching electromagnetic valve, and is configured to communicate the discharge port 33b of the pump 33 and the filter 34 when turned on, and to communicate the discharge port 33b of the pump 33 and the atmosphere when turned off. The
[0014]
A pressure sensor (not shown) that detects the pressure in the chamber 12 is provided in the main chamber 12. The detection output of this pressure sensor is connected to the control input of a controller (not shown), and the control output of the controller is connected to the head vacuum pump 33, the first on-off valve 51, the second on-off valve 52, and the switching valve 36, respectively. The The operation state of the pulling device 10, specifically, whether the inside of the main chamber 12 is a predetermined negative pressure or atmospheric pressure is detected by the pressure sensor. That is, when the inside of the main chamber 12 is at a predetermined negative pressure, the controller determines that the silicon single crystal rod 11 is being pulled up (hereinafter referred to as a pulled state), and the inside of the main chamber 12 is at atmospheric pressure. Is determined to be in a state in which a material such as a silicon polycrystal is set in the main chamber 12 (hereinafter referred to as a preparation state).
[0015]
Further, although not shown, a quartz crucible for storing silicon melt is provided in the main chamber 12, and this quartz crucible is connected to the crucible driving means via a support shaft. The outer peripheral surface of the quartz crucible is surrounded by a carbon heater at a predetermined interval from the quartz crucible, and this heater is surrounded by a heat insulating cylinder. The heater is configured to heat and melt a high-purity silicon polycrystal charged in a quartz crucible to form a silicon melt. The drum driving motor 23 and the head vacuum pump 33 are configured to be supplied with power via a slip ring and an electric brush (not shown).
[0016]
The operation of the silicon single crystal pulling apparatus thus configured will be described.
In the preparation state of the pulling device 10, the inside of the main chamber 12 and the head chamber 16 are opened to the atmosphere, and the quartz crucible is filled with silicon polycrystal, or the winding drum 22 is driven to rotate by the drum driving motor 23. An operation of feeding or winding the wire 13 and attaching the seed crystal 31 to the chuck 32 at the tip of the wire 13 is performed. When the wire 13 is fed or wound, the drive gear 28 and the driven gear 29 are engaged with each other (a slight slip occurs between the tooth surfaces), or the wire 13 is rubbed against the outer peripheral surface of the drum 22 or the like. Dust is generated in the head chamber 16 when the drum 22 slides with respect to the shaft 24 or when the fixed pulley 21 and the bearing 27 rotate.
[0017]
On the other hand, when the pressure sensor detects that the inside of the main chamber 12 is atmospheric pressure, the controller determines that the pulling device 10 is in the ready state, and turns on the first and second on-off valves 51 and 52 to turn on the first and The third pipes 41 and 43 are opened, the switching valve 36 is turned on, and the discharge port 33 b of the head vacuum pump 33 is communicated with the filter 34. When the head vacuum pump 33 is operated in this state, the air in the head chamber 16 flows into the filter 34 via the first pipe 41, the head vacuum pump 33 and the second pipe 42. The dust contained in the air is removed, and the purified air returns to the head chamber 16 again through the third conduit 43. As a result, the dust generated in the head chamber 16 is quickly removed by the filter 34, so that the dust does not enter the main chamber 16.
[0018]
When preparation of the pulling device 10 is completed, a main vacuum pump (not shown) is operated to suck air until the inside of the main chamber 12 reaches a predetermined negative pressure, and supply inert gas into the main chamber 12. Then, the air is replaced with an inert gas. Since the inside of the head chamber 16 is also in communication with the main chamber 12, a predetermined negative pressure is reached and the air in the head chamber 16 is replaced with an inert gas. Also, the heater is operated to melt the silicon polycrystal in the quartz crucible to form a silicon melt, and the wire 13 is fed to immerse the seed crystal 31 attached to the chuck 32 in the silicon melt. At this time, dust is generated in the head chamber 16 by the feeding of the wire 13 in the same manner as described above.
[0019]
On the other hand, when the pressure sensor detects that the inside of the main chamber 16 has a predetermined negative pressure, the controller determines that the pulling device 10 has been pulled up, and the second open / close valve 52 remains on while the first open / close valve 51 remains on. Is turned off, the third pipe 43 is closed, and the switching valve 36 is turned off to allow the discharge port 33b of the head vacuum pump 33 to communicate with the atmosphere. As a result, the inert gas in the head chamber 16 is quickly discharged into the atmosphere together with dust by the operation of the head vacuum pump 33, so that the dust does not enter the main chamber 12 and dust (particles) is removed. The high-purity silicon single crystal rod 11 not included can be pulled up.
[0020]
In order to prevent the inert gas in the head chamber 16 from being pulled into the main chamber 12 when the silicon single crystal rod 11 is pulled up, the head vacuum pump 33 needs to use a pump having a larger suction capacity than the main vacuum pump. There is. For example, when the pressure in the main chamber 12 is 10 Torr, it is necessary to use the head vacuum pump 33 capable of setting the pressure in the head chamber 16 to 5 Torr. When the pressure in the main chamber 12 is 30 Torr, the head chamber It is necessary to use the vacuum pump 33 for the head which can make the pressure in 16 to 15-20 Torr. On the other hand, when only a pump having a suction capacity smaller than that of the main vacuum pump can be used as the head vacuum pump 33, the first and second on-off valves 51 and 52 are turned off when the pulling device 10 is pulled up. The first and third pipe lines 41 and 43 are closed, and the head vacuum pump 33 is stopped.
[0021]
【The invention's effect】
As described above, according to the present invention, the suction port of the head vacuum pump is connected to the head chamber, and the head vacuum pump is configured to suck and discharge the dust generated in the head chamber. Even if dust is generated from the sliding portion of the wire in the head chamber, the head vacuum pump quickly sucks and discharges the dust out of the head chamber. As a result, since the dust does not enter the main chamber, a high-purity silicon single crystal rod not containing dust (particles) can be pulled up.
Also, if the discharge port of the head vacuum pump is connected to the head chamber via a filter and the dust generated in the head chamber is collected by the filter, the gas in the head chamber together with the dust is vacuumed for the head. After being sucked by the pump and dust in the gas is collected and purified by the filter, the purified gas returns to the head chamber again. As a result, the dust can be prevented from entering the main chamber as described above.
[0022]
Further, a first opening / closing valve for opening and closing the first pipe line is provided in the first pipe line, and a switching valve for switching the discharge port of the head vacuum pump so as to communicate with the filter or the atmosphere is provided in the second pipe line. A second on-off valve for opening and closing the third pipe is provided in the pipe, and the controller controls the head vacuum pump, the first on-off valve, the switching valve, and the second on-off valve in accordance with the operating state of the pulling device. With this configuration, when the inside of the main chamber is opened to the atmosphere, the controller opens the first and second on-off valves, and switches the switching valve so that the discharge port of the head vacuum pump and the filter communicate with each other. As a result, the dust generated in the head chamber is quickly collected by the filter, and the purified air is returned to the head chamber, so that the dust can be prevented from entering the main chamber.
On the other hand, when the inside of the main chamber reaches a predetermined negative pressure, the controller opens the first on-off valve, closes the second on-off valve, and switches the switching valve so that the discharge port of the head vacuum pump communicates with the atmosphere. As a result, dust generated in the head chamber is discharged into the atmosphere, so that the dust can be prevented from entering the main chamber.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part including a head of a silicon single crystal pulling apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Silicon single crystal pulling apparatus 11 Silicon single crystal rod 12 Main chamber 13 Wire 14 Wire winding mechanism 16 Head chamber 33 Vacuum pump 33a for head 33 Suction port 33b Discharge port 34 Filter 41 First pipe line 42 Second pipe line 43 Third Pipe line 51 First on-off valve 52 Second on-off valve

Claims (2)

A wire (13) pulled up while rotating the silicon single crystal rod (11) from the silicon melt in the main chamber (12), a wire winding mechanism (14) for winding the wire (13), and the wire winding In the silicon single crystal pulling apparatus including the take-up mechanism (14) and the head chamber (16) communicating with the main chamber (12),
The suction port (33a) of the head vacuum pump (33) is connected to the head chamber (16),
The head vacuum pump (33) is configured to suck and discharge dust generated in the head chamber (16) ,
The discharge port (33b) of the head vacuum pump (33 ) is connected to the head chamber (16) via a filter (34) ,
A head structure for a silicon single crystal pulling apparatus, wherein dust generated in the head chamber (16) is collected by the filter (34) . A first on-off valve (51) provided in a first pipe (41) for connecting the suction port (33a) of the head vacuum pump (33) and the head chamber (16) to open and close the first pipe (41). )When,
The discharge port (33b) of the head vacuum pump (33) is provided in a second pipe (42) connecting the discharge port (33b) of the vacuum pump for head (33) and the filter (34). (34) or a switching valve (36) that switches to communicate with the atmosphere,
A second on-off valve (52) provided in a third pipe (43) connecting the filter (34) and the head chamber (16) to open and close the third pipe (43);
A controller for controlling the head vacuum pump (33), the first on-off valve (51), the switching valve (36) and the second on-off valve (52) according to the operating state of the pulling device (10). The head structure of the silicon single crystal pulling apparatus according to claim 1, which is provided.

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