JP3203342B2 - Single crystal manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus for manufacturing a single crystal used as a material of a single crystal substrate for manufacturing a semiconductor circuit.

[0002]

2. Description of the Related Art In the field of semiconductor manufacturing, the Czochralski method has been generally used as a method for growing a silicon single crystal. As an example of an apparatus using this method, for example, an apparatus as shown in FIG. 4 (Japanese Patent Application Laid-Open No. 64-72984) can be exemplified.

An apparatus 1 shown in FIG. 4 comprises a heating chamber 2a for mainly containing a structure for melting silicon and a pulling chamber 2 for storing a silicon crystal S to be pulled.
The crucible 5 and the heater 6 arranged so as to surround mainly the side surface of the crucible 5 are provided in the heating chamber 2a. The crucible 5 contains the silicon melted by the heater 6. The crucible 5 is connected to a driving device (not shown) by the rotating shaft 4, and is rotated at a predetermined speed by the driving device. Usually, the crucible 5 includes a quartz crucible 5a and a graphite crucible 5b for protecting the quartz crucible 5a.

On the other hand, the lifting chamber 2b has a ceiling 3a for closing the opening of the heating chamber 2a, and a ceiling 3a.
And a housing portion 3b mainly housing the silicon single crystal body S being grown. A cylinder 25 extending toward the crucible 5 is attached to a joint of the housing 3b with the ceiling 3a. In the pulling chamber 2b, there is provided a pulling wire 7 penetrating the top wall and hanging down. At the lower end of the pulling wire 7, a chuck 9 for holding a seed crystal 8 is provided.
The upper end side of the pulling wire 7 is wound around a wire hoist 10 so as to pull up the silicon crystal S being grown at a predetermined speed. Note that a heat insulating member 11 is provided on the heating chamber 2a side of the illustrated heater 6.
This is to prevent heat from the heater 6 from escaping to the outside of the heating chamber 2a.

In the chamber 2, a lifting chamber 2b
Argon gas is introduced from the gas inlet 12 formed in the cylinder 25. The argon gas passes through the inside of the housing 3b from the gas inlet 12 as shown in FIG. Heating chamber 2 passing inside
a, and is discharged from the gas discharge port 13. The flow of the argon gas in this way is for cooling the growing silicon single crystal S introduced into the cylinder 25,
SiO generated in chamber 2 as silicon is melted
This is for discharging gas out of the system. The silicon single crystal body S being pulled up by the action of the cylinder 25 is rapidly cooled, and the pulling speed is improved to increase the productivity.

In a part of the ceiling portion 3a of the pulling chamber 2b, a state of a solid-liquid interface which is a boundary surface between the melt melted in the crucible 5 and the outer peripheral surface of the silicon single crystal S pulled from the crucible 5 is provided. The observation hole 26 for observing is opened. A camera 27 for observing the diameter and for observing the state of the solid-liquid interface is installed in the viewing hole 26 as shown in the figure. Based on a signal from the camera 27, a silicon single crystal having a desired diameter is pulled up. Thus, the lifting speed of the wire hoisting machine 10 is adjusted.

[0007] In addition to the above techniques, for example,
There is also a structure as shown in FIG. 5 disclosed in Japanese Patent No. 40119.

The structure shown in this figure has many parts in common with the structure shown in FIG. 4, but the only difference is that the structure shown in FIG. While a cylinder 25 for promoting cooling is attached, the one shown in FIG. 5 has a V-shaped cross section 30 attached for the same purpose.

The board 30 has an outer peripheral end attached to and supported by the heat insulating member 11. This board 30
Is formed concentrically with a flat portion 30a.
An inclined wall 30b inclined toward the melting surface of the crucible 5 extends from the inner peripheral end of Oa toward the melt surface of the crucible 5 while being reduced in diameter.
The end of the inclined wall 30b is located near the solid-liquid interface described above. The opening diameter of the opening near the solid-liquid interface formed by the inclined wall 30b is set to a size such that the camera 27 can image the state of the solid-liquid interface as shown in the figure.

Since the board 30 is arranged so as to surround the outer peripheral wall of the crucible 5, the radiant heat of the heater 6 to the silicon single crystal S is almost completely blocked by the board 30. In other words, the cooling of the top portion side of the silicon single crystal body S to be pulled up is considerably promoted as compared with the case where the silicon single crystal body S is not provided.

[0011]

However, in a conventional single crystal manufacturing apparatus having such a structure, FIG.
In the structure having the structure shown in FIG. 1, the outer periphery of the silicon single crystal body S located inside the cylinder 25 is cooled by the action of the cylinder 25.
5 is heated by the melt or the radiant heat from the heater 6, so that the cooling of the silicon single crystal body S is promoted as compared with the case where the cylinder 25 is not provided. There was still room for improvement.

In the structure having the structure shown in FIG. 5, the silicon single crystal S
Has been found to be quite efficient but has unacceptable defects in terms of obtaining good quality silicon single crystals.

That is, when a single crystal was manufactured using the board 30, there was a case where OSF defects were remarkably generated in the manufactured single crystal. As a result of the inventor's research to solve this problem and to produce a high-quality single crystal that could not be obtained by the conventional pulling method, the cause of the crystal defects is that the crystal heat history after solidification is It turned out to be a problem. That is, in the apparatus having the configuration shown in FIG. 5, when the cooling rate of the silicon single crystal body S, especially the cooling rate of the portion immediately above the solidification interface is rapidly cooled,
SF is generated. Thereafter, the cooling rate of the pulled-up silicon single crystal S is reduced, and the pulled-up single crystal S is further rapidly cooled, so that the generation of OSF is extremely reduced. At the same time, it has been found that the degree of oxygen precipitation that occurs when a heat treatment is performed on a silicon wafer manufactured using the single crystal body S can be reduced.

The present invention has been made in view of such a conventional problem, and a single crystal having a high quality can be obtained by controlling the thermal history of the single crystal. The purpose of the present invention is to provide a manufacturing apparatus.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a heating apparatus having a built-in crucible for accommodating a melt and a heater arranged to surround the outer periphery of the crucible and heating the crucible. A chamber and a heating chamber ceiling portion that covers an opening of the heating chamber are formed, and a storage portion that stores therein a single crystal body that is pulled up from the crucible is formed at a center portion of the ceiling portion, and the ceiling portion is formed. In a single crystal manufacturing apparatus provided with a pulling chamber formed with an observation hole for looking into a solid-liquid interface between the melt and the outer peripheral surface of the single crystal body to be pulled up, the heating chamber or the pulling chamber is A disk portion extending in the direction of the crucible to the vicinity of the growing single crystal, and pulling of the growing single crystal toward the inner circumferential direction from the middle of the disk portion; A heat shield that gradually reduces and elongates the diameter of the solid-liquid interface from an angle that does not hinder the view of the solid-liquid interface from the eye and the viewing hole, and blocks radiant heat from the heater radiated toward the single crystal body to be pulled up. A heat history forming member comprising a wall portion is provided.

Further, a heating chamber having a built-in crucible for accommodating the melt, a heater arranged to surround the outer periphery of the crucible and heating the crucible, and a ceiling portion of a heating chamber covering an opening of the heating chamber Is formed, a storage portion for storing therein a single crystal body pulled up from the crucible is formed in a central portion of the ceiling portion, and the melt and the single crystal body outer peripheral surface pulled up are formed on the ceiling portion. In a single crystal manufacturing apparatus provided with a pull-up chamber formed with a peep hole for looking into the solid-liquid interface of the pull-up chamber, extending from the junction between the ceiling portion and the storage portion of the pull-up chamber in the crucible direction, A cylindrical portion provided so as to surround the single crystal body being grown, a disk portion projecting outward from a lower end portion of the cylindrical portion, and an inner peripheral portion extending from an outer peripheral end portion of the disk portion. The heating heater which is gradually reduced in diameter and extended at an angle so as not to hinder the pulling of the growing single crystal body and the view of the solid-liquid interface from the viewing hole toward the cylindrical portion, and radiates toward the cylindrical portion. And a heat history forming member configured by a heat shield wall portion for blocking radiant heat from the heat history.

[0017]

The apparatus for producing a single crystal of the present invention having the above-described structure functions as follows. First, the solidified solid that has been solidified is rapidly cooled because heat radiation from the heater is interrupted by the presence of the heat shield wall. afterwards,
Due to the presence of the disk portion, heat radiation from the single crystal body to the ceiling of the chamber being cooled is interrupted, and the cooling rate is reduced. In the portion where the single crystal reaches the upper portion than the disk portion, heat radiation from the single crystal to the ceiling is promoted, and the single crystal is rapidly cooled. In the case of having a cylindrical part on the disk part, the single crystal above the disk part is based on the effect of rectifying the flow of argon gas and the effect of promoting heat conduction to the ceiling through the cylindrical part. It is possible to accelerate quenching of the body more.

The thermal history of the single crystal can be made ideal by the effect of the thermal history forming member, and the quality of the single crystal can be improved, specifically, the occurrence of OSF defects can be suppressed, and
It becomes possible to realize suppression of oxygen precipitation.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an apparatus for producing a single crystal according to the present invention. This single crystal manufacturing apparatus 1
Has a member for melting silicon, a mechanism for pulling up crystallized silicon, and the like. The member for melting silicon is accommodated in the heating chamber 2a, and a mechanism for pulling up the silicon single crystal is provided in the heating chamber 2a. Pull-up chamber 2 which can be separated from separation chamber 2a by a separation mechanism
b.

A crucible 5 for accommodating molten silicon is provided in the heating chamber 2a. The crucible 5 is supported by a driving device (not shown) by a rotating shaft 4 so as to be rotatable and vertically movable. The driving device 22 is configured to compensate for a drop in the liquid level due to the pulling of the silicon single crystal S by using the crucible 5.
The crucible 5 is constantly rotated at a predetermined number of revolutions in order to stir the silicon melt. The rotating shaft 4 penetrates through the heating chamber 2a, but is held by special bearings (not shown) to keep the inside and outside of the chamber airtight and to be used under extremely poor temperature conditions. . The crucible 5 comprises a quartz crucible 5a and a graphite crucible 5b for protecting the same as in the prior art.

On the side wall portion of the crucible 5, a heater 6 for melting silicon is arranged so as to surround the periphery thereof. Outside the heater 6, a heat insulating member 11 for preventing heat from the heater 6 from being directly radiated to the heating chamber 2a is provided so as to surround the periphery thereof. Note that the heater 6 and the heat insulating member 11 are attached to a support 24. The support 24 is manufactured using a material having a very large thermal resistivity.

One end of the wire hoisting machine 10 is attached to the lifting chamber 2b.
Is provided with a pull-up wire 7 which is inserted through the top wall of the housing portion 3b and is hung down.
A chuck 9 for holding a seed crystal 8 is attached.
The wire hoist 10 pulls up the silicon single crystal S that gradually grows on the lower end side of the seed crystal 8 in accordance with the growth rate or the like, and at the same time, constantly rotates the crucible 5 in the direction opposite to the rotation direction.

Heating chamber 2a and lifting chamber 2b
From the vicinity of the separation mechanism of the heating chamber 2a, a disk portion 44A extending toward the crucible 5 is provided. Therefore, the shape of the disk portion 44 is such a hollow disk that at least the silicon single crystal body S can be pulled up freely. Also, the peephole 26
Providing a window in this hollow disk so that the state of the solid-liquid interface can be observed from this does not impair the function of the disk portion.
A heat shield wall portion 46 is formed from the middle of the disk portion 44A and is inclined toward the melting surface of the crucible 5 and extends in the melt direction while reducing the diameter. The end of the heat shield wall 46 in the direction of the melt is located near the solid-liquid interface between the melt and the silicon single crystal S.

Further, the housing 3b of the lifting chamber 2b
Is provided with a gas inlet 12 for introducing an argon gas into the chamber 2. Argon gas is introduced from the gas inlet 12, and the argon gas flows into the pull-up chamber 2 b and flows into the silicon chamber. The crystal S is cooled, and then flows into the heating chamber 2a from near the solid-liquid interface and is discharged from the gas outlet 13. The flow of the argon gas in this way is for two reasons, namely, for rapidly cooling the silicon single crystal S and discharging the SiO 2 gas generated in the chamber 2 due to the melting of silicon to the outside of the system. .

In a part of the ceiling portion 3a of the pulling chamber 2b, a state of a solid-liquid interface which is a boundary surface between the melt melted in the crucible 5 and the outer peripheral surface of the silicon single crystal body S pulled up therefrom is provided. The observation hole 26 for observing is opened. A camera 27 for observing the diameter and for observing the state of the solid-liquid interface is installed in the viewing hole 26 as shown in the figure. Based on a signal from the camera 27, a silicon single crystal having a desired diameter is pulled up. Thus, the lifting speed of the wire hoisting machine 10 is adjusted. Therefore, as described above, the disc portion 4 is so arranged that the view from the camera 27 is not obstructed.
Consideration is given to the shape of the 4A window and the shape of the heat shield wall 46.

With such a configuration, the solidified silicon single crystal body S is provided with the heat shielding wall 46.
As a result, the radiant heat from the heater 6 is blocked, so that the part pulled up from the solid-liquid interface to some extent is rapidly cooled. This quenching is further facilitated by the flow of argon gas. In the portion where the lifting is further advanced, that is, in the portion until reaching the vicinity of the inner peripheral end of the disk portion 44A, the cooling of the argon gas is performed, but the degree is much smaller than that near the solid-liquid interface,
In addition, since the radiant cooling to the ceiling 3a is interrupted by the disk portion 44A, a gradually cooled state is achieved. And the disk part 44
Above A, radiant cooling to the ceiling 3a is effective,
This time it will be quenched. Since the thermal history changes in this way, it is possible to prevent the occurrence of OSF defects and suppress the oxygen precipitation.

Next, FIG. 2 shows a configuration according to a second embodiment of the present invention. According to this embodiment,
The heat history forming member attached to the junction between the ceiling portion 3a and the housing portion 3b of the lifting chamber 2b instead of the heat shield wall portion 46 being supported by the disk portion 44A attached to the heating chamber 2a. It has the feature that it can be supported by 40. The heat history forming member 40 includes a cylindrical portion 42, a disk portion 44, and a heat shield wall portion 46.

As shown, a cylindrical portion 42 extending toward the crucible 5 extends from the inner surface near the junction between the ceiling portion 3a and the accommodation portion 3b of the lifting chamber 2b. At the lower end of the cylindrical portion 42, there is formed a disk portion 44 which protrudes horizontally toward the outside, and a part of the disk portion 44 is provided so that the state of the solid-liquid interface can be observed from a peephole 26 described later. Opening 48 is formed at an optimum position. Further, from the outer peripheral portion of the disk portion 44, a heat shield wall portion 46 which is inclined toward the melting surface of the crucible 5 and extends in the melt direction while reducing the diameter is formed. The end of the heat shield wall 46 in the direction of the melt is located near the solid-liquid interface between the melt and the silicon single crystal S. The angle of inclination of the heat shield wall 46 and the diameter of the opening located in the vicinity of the melt formed by the heat shield wall 46 are determined by the size of the peephole 2.
The angle and the aperture diameter are set so that the camera view from the aperture 6 and the opening 48 is not obstructed.

Further, the housing 3b of the lifting chamber 2b
Is provided with a gas inlet 12 for introducing an argon gas into the chamber 2. An argon gas is introduced from the gas inlet 12, and the argon gas is supplied to the heat history forming member 40 and the heat history forming member 40. It passes between the silicon single crystal S drawn into the member 40, flows into the heating chamber 2 a from near the solid-liquid interface, and is discharged from the gas outlet 13.

The position of the opening 48 and the shape of the heat shield wall 46 are taken into consideration so as not to obstruct the field of view from the camera 27 as described above. Of course, the heat-insulating wall 46 and the cylindrical portion 42 have the heat-shielding properties and heat-absorbing properties taken into consideration first, and all factors such as their shapes and sizes are determined so that an ideal heat history is realized. Needless to say.

By providing the cylindrical portion 42 between the disk portion 44 and the ceiling portion 3b as described above, the effect of improving the quality can be further ensured. This is because the provision of the cylindrical portion 42 allows the argon gas to flow in a space between the inner wall of the cylindrical portion 42 and the silicon single crystal body S in a rectified manner, and thus the argon gas flows above the disk portion 44. Cooling rate of the silicon single crystal body S located in the
This is because, compared with the case where the cylindrical portion 42 does not exist, the process can be performed earlier and the generation of crystal defects can be further reduced.

Next, the operation of the apparatus of the present invention configured as described above will be described in detail.

First, in manufacturing a silicon single crystal, the pulling chamber 2b is separated from the heating chamber 2a, and the silicon coarse crystal as a raw material and a very small amount of impurities are charged into the crucible 5, and the pulling chamber 2b is placed in the crucible 5. It is attached to the heating chamber 2a. In this state, the heater 6 is heated to wait for the silicon in the crucible 5 to be melted.
When this silicon is in a molten state, the wire winding machine 10
Is operated to lower the pull-up wire 7 so that the seed crystal attached to the chuck 9 contacts the surface of the silicon melt. In this state, when the silicon crystal begins to grow on the seed crystal, the wire hoist 10 is pulled up at a predetermined speed to grow the silicon single crystal S as shown in FIG. When the top portion of the silicon single crystal body S is drawn into the cylindrical portion 42 by this pulling, the silicon single crystal body S is rapidly cooled by the argon gas flowing through the inside. On the other hand, the portion of the silicon single crystal S located between the crucible 5 and the cylindrical portion 42 is cooled down more slowly than the inside of the cylindrical portion 42 because the degree of cooling is suppressed by the action of radiant heat from the melt. Become so. The heat shield wall portion 46 surrounds the side peripheral portion of the crucible 5 and the cylindrical portion 4 from the heater 6.
Radiation heat in two directions is blocked to some extent. For this reason, the degree to which the cylindrical portion 42 is heated by radiant heat incident from the outside is extremely reduced, and the cooling of the silicon single crystal body S drawn into the cylindrical portion 42 is reduced by an amount corresponding to the suppression of the external heating. Will be promoted.

Accordingly, for example, a portion from the vicinity of the solid-liquid interface between the melt and the silicon single crystal body S to the portion 100 mm or less from the solid-liquid interface drawn into the cylindrical portion 42 is almost gradually cooled, In this case, the heat shield wall portion 46 and the cylindrical portion 42
Quenched by the heat shielding effect. As a result, the occurrence of OSF defects can be suppressed to some extent without lowering the pulling speed.

Next, FIG. 3 shows a configuration according to a third embodiment of the present invention. According to this embodiment, in addition to the configuration of the second embodiment, the disk portion 44A extends outward from the upper edge of the heat shield wall portion 46 so that the disk portion 44A extends from between the heating chamber 2a and the heat shield wall portion 46. The flow of argon gas is interrupted, and the argon gas flows into the silicon single crystal body S and the heat shield wall 46.
It is arranged so as to pass only between and. According to this configuration, the heat history imparted to the silicon single crystal body S is almost the same as that of the second embodiment, but the SiO 2 powder generated in the gas on the melt surface by this configuration is transferred from the crucible 5 to the outside of the system. It is possible to reduce the harmful effects of polycrystallization of the silicon single crystal discharged and pulled up.

According to the configuration of the above embodiment, the vicinity of the solid-liquid interface between the melt and the silicon single crystal S is 100 m from the interface.
The portion up to m is quenched, gradually cooled from 100 mm until it passes through the disk portion, and the upper portion passing through the disk portion is quenched. As a result, it is possible to realize an ideal thermal history, and it is possible to prevent the occurrence of OSF defects and suppress the oxygen precipitation.

Since the angle of inclination is such that the field of view from the camera 27 to the solid-liquid interface is not obstructed, the pulling speed of the silicon single crystal body S is adjusted while checking the crystal growth state. be able to. As a result, the silicon single crystal body S can be grown while maintaining the desired diameter.

In the configuration of the above embodiment, most of the argon gas flows from the opening of the heat shield wall portion 46 toward the solid-liquid interface of the silicon single crystal S, so that an ideal gas flow path is provided. It can be. That is, the SiO 2 precipitate generated from the melt surface can be effectively discharged out of the system.

[0039]

As described above, according to the present invention, the heat history of quenching, slow cooling, and quenching is applied after pulling, so that the productivity of the single crystal body is improved while suppressing the deterioration in quality. Will be able to do that.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for producing a single crystal according to the present invention.

FIG. 2 is a schematic configuration diagram of an apparatus for producing a single crystal according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an apparatus for producing a single crystal according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional single crystal manufacturing apparatus.

FIG. 5 is a schematic configuration diagram of another conventional single crystal manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Single crystal manufacturing apparatus 2 ... Chamber 2a ... Heating chamber 2b ... Pull-up chamber 5 ... Crucible 6 ... Heater 7 ... Pull-up wire 8 ... Seed crystal 40 ... Heat history forming member 42 ... Cylindrical part 44 ... Disk part 44A … Disc part 46… Heat-shield wall part 48… Opening

Continuation of the front page (72) Inventor Shigeru Takao 3434 Shimada, Hikari-shi, Yamaguchi Prefecture Inside Nippon Steel Corporation Hikari Works (56) References JP-A-3-218994 (JP, A) JP-A-64 JP-A-72984 (JP, A) JP-A-3-177389 (JP, A) JP-A-3-97688 (JP, A) JP-A-64-65086 (JP, A) JP-A-2-57962 (JP, U) (Japanese Patent Publication No. Sho 57-40119 (JP, B2)) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00

Claims (2)

(57) [Claims] 1. A heating chamber having a built-in crucible for accommodating a melt, a heater arranged to surround the outer periphery of the crucible and heating the crucible, and a ceiling portion of a heating chamber covering an opening of the heating chamber. Is formed, a storage portion for storing therein a single crystal body pulled up from the crucible is formed in a central portion of the ceiling portion, and the melt and the single crystal body outer peripheral surface pulled up are formed on the ceiling portion. A production chamber provided with a pulling chamber formed with a peephole that looks into the solid-liquid interface of the above, wherein the heating chamber or the pulling chamber extends from the heating chamber or the pulling chamber toward the crucible in the vicinity of the growing single crystal. The solid-liquid interface is not hindered from pulling up the growing single crystal body from the middle of the disk portion toward the inner circumferential direction and from the viewing hole. A heat history forming member is provided, which comprises a heat shield wall portion that gradually reduces and elongates the diameter at such an angle and blocks radiant heat from the heater radiated toward the single crystal body to be pulled up from the heater. An apparatus for producing a single crystal. 2. A heating chamber having a built-in crucible containing a melt, a heater arranged to surround the outer periphery of the crucible and heating the crucible, and a heating chamber ceiling covering an opening of the heating chamber. Is formed, a storage portion for storing therein a single crystal body pulled up from the crucible is formed in a central portion of the ceiling portion, and the melt and the single crystal body outer peripheral surface pulled up are formed on the ceiling portion. In a single crystal body manufacturing apparatus provided with a pulling chamber formed with a peephole that looks into the solid-liquid interface of the pulling chamber, the pulling chamber extends from the junction between the ceiling portion and the storage portion in the crucible direction, A cylindrical portion provided so as to surround the single crystal body being grown, a disk portion projecting outward from a lower end portion of the cylindrical portion, and an inner circumferential direction from an outer peripheral end portion of the disk portion. Then, the diameter of the solid-liquid interface is gradually reduced and extended at an angle that does not hinder the pulling-up of the growing single crystal body and the view of the solid-liquid interface from the viewing hole, and the heater is radiated toward the cylindrical portion. An apparatus for producing a single crystal, characterized in that a heat history forming member constituted by a heat shield wall portion for blocking radiant heat is provided.