KR101395392B1 - Growing Method for Silicon Single Crystal Ingot - Google Patents

Abstract

The embodiment relates to a method of growing a silicon single crystal ingot.
A method of growing a silicon single crystal ingot according to an embodiment includes melting a polycrystalline silicon in a crucible, conducting a necking process using a single crystal seed, A body processing step of growing a single crystal ingot in the radial direction of the seed and advancing the body after advancing the shoulder so as to have a predetermined diameter; And a tailing process of reducing the diameter of the body and separating the melt from the melt. The diameter of the body of the single crystal ingot is 400 mm or more, and when the tailing process is performed, the melt gap is 35 mm or less .

Description

Growing Method for Silicon Single Crystal Ingot

The embodiment relates to a method of growing a silicon monocrystal ingot.

Silicon wafers, which are mainly used as substrates in the manufacture of semiconductor devices, generally have high-purity polycrystalline silicon produced, and then monocrystals are grown from polycrystalline silicon according to the Czochralski (CZ) crystal growth method, The wafer is sliced to produce a silicon wafer. The wafer is mirror-polished, cleaned, and finally inspected.

For example, in the conventional single crystal ingot growing method, after a seed is immersed in a melt in which polycrystalline silicon is melted, the seed crystal is grown at a high pulling rate to proceed the necking process. Then, the single crystal is gradually grown in the radial direction with the seed, and if the seed crystal has a predetermined diameter, the shouldering step is performed. The body growth is performed after the shouldering step, the body is processed for a predetermined length, the diameter of the body is decreased, and the single crystal ingot growth is completed through a tailing process in which the body is separated from the melt.

According to the prior art, since a large-diameter single crystal ingot, for example, a single crystal ingot of 400 mm or more, has a volume larger than that of a 300 mm single crystal ingot, the cooling driving force of the single crystal due to the lowering of the melt level in the tailing process There is a problem that a pop-out phenomenon in which a growing silicon single crystal ingot is inadvertently separated from a silicon melt is likely to occur.

The present invention provides a method for growing a silicon single crystal ingot which can improve the production yield of large diameter silicon single crystal ingots.

A method of growing a silicon single crystal ingot according to an embodiment includes melting a polycrystalline silicon in a crucible, conducting a necking process using a single crystal seed, A body processing step of growing a single crystal ingot in the radial direction of the seed and advancing the body after advancing the shoulder so as to have a predetermined diameter; And a tailing process of reducing the diameter of the body and separating the melt from the melt. The diameter of the body of the single crystal ingot is 400 mm or more, and when the tailing process is performed, the melt gap is 35 mm or less .

The embodiment can provide a method of growing a silicon monocrystalline ingot capable of improving the production yield of a large-diameter silicon single crystal ingot by reducing the possibility of pop-out in a tailing process of the silicon single crystal ingot.

1 is a schematic view of an apparatus for producing a single crystal ingot according to an embodiment.
Fig. 2 is an example of a change in melt-gap according to the length of the tees in the method of growing a single crystal ingot in the embodiment and the prior art. Fig.
Figure 3 is an exemplary photograph of a monocrystalline ingot popped out during a tailing process in a monocrystalline ingot according to the prior art.
4 is a photograph of an example of a full structure single crystal ingot grown according to the method of manufacturing a single crystal ingot according to an embodiment.
Fig. 5 is an illustration of a crucible lift change according to the length of the tees in the embodiment and the prior art. Fig.
Fig. 6 is an exemplary diagram illustrating the seed rotation change according to the length of the tees in the embodiment and the prior art; Fig.
FIG. 7 is an exemplary diagram showing a change in magnetic field according to a length of a tee in the embodiment and the prior art. FIG.

In the description of the embodiments, each wafer, apparatus, chuck, member, sub-region, or surface is referred to as being "on" or "under" Quot ;, " on "and" under "include both being formed" directly "or" indirectly " In addition, the criteria for "up" or "down" of each component are described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

(Example)

1 is a schematic view of an apparatus for producing a single crystal ingot according to an embodiment.

The silicon single crystal growth apparatus 100 according to the embodiment may include a chamber 110, a crucible 112, a heater 120, a lifting means 128, and the like.

For example, the single crystal ingot growing apparatus 100 according to the embodiment includes a quartz crucible 112 in which a silicon melt SM is contained as a hot zone structure in the chamber 110, and a quartz crucible 112 And a support structure 116 for supporting a load is placed on the lower portion of the graphite crucible. The support structure 116 is condensed in a rotation drive device (not shown) (Not shown).

The chamber 110 may provide a space in which predetermined processes for growing a single crystal ingot for a silicon wafer used as an electronic component material such as a semiconductor are performed.

A heater 120 as a heat source for supplying heat energy required for growing a single crystal ingot IG is surrounded by the outer periphery of the graphite crucible 114 and the heat of the heater is discharged to the side of the chamber 110 by the outer edge of the heater A side shielding system 130 consisting of a heat shield 132 and side insulation 134 is enclosed to shield the heat.

A lower insulation system 140 composed of a shielding plate 142 and a lower insulation member 144 may be mounted to the lower portion of the heater 120 so as to prevent the heat of the heater from being discharged to the lower portion of the chamber.

An upper insulation system 150 including a heater cover 152 and an upper insulation 154 may be mounted on the upper side of the side insulation system 130 so as to prevent the heat of the heater from being emitted to the upper portion of the chamber.

In the upper insulating system 150, a single crystal ingot is interposed between the single crystal ingot IG and the quartz crucible 112 to block the heat released from the silicon melt SM, A heat shield 122 may be mounted to provide a cooling drive force to dissipate heat released from the silicon melt and transferred to the silicon ingot.

An impression for growing the ingot by dipping the seed crystal S connected to the lifting means 128, for example, a cable, into the silicon melt SM at the upper part of the chamber 110 while rotating it at a predetermined speed, A pullup device is installed and a gas supply pipe (not shown) for supplying an inert gas such as argon (Ar) or neon (Ne) to the inside of the chamber may be formed.

A vacuum exhaust pipe (not shown) may be formed in the lower portion of the chamber 110 and connected to the vacuum exhaust connection to evacuate and exhaust the inert gas supplied from the gas supply pipe.

Here, the inert gas supplied to the vacuum pumping force of the vacuum exhaust pipe from the gas supply pipe to the inside of the chamber has a down flow.

As an example of a manufacturing method for a silicon single crystal ingot growing method, a Czochralski (CZ) method of growing a crystal by immersing a seed crystal, which is a single crystal, in a silicon melt (SM) .

According to this method, after the seed is dipped in the molten melt of the polycrystalline silicon, the seed crystal is grown at a high pulling rate and the necking process is carried out. Then, the single crystal is gradually grown in the radial direction with the seed, and if the seed crystal has a predetermined diameter, the shouldering step is performed. The body growth is continued after the shoulder ringing step, the body diameter is decreased by a predetermined length, and the body is separated from the melt, and the monocrystalline ingot is grown by a tailing process.

After the cryoping process for cutting the body portion of the crystal-grown single crystal ingot to a predetermined size, the outer surface is grinded such that the remaining portion of the rod has a predetermined diameter.

According to the prior art, since a large-diameter single crystal ingot, for example, a single crystal ingot of 400 mm or more, has a volume larger than that of a 300 mm single crystal ingot, the cooling driving force of the single crystal due to the lowering of the melt level in the tailing process There is a problem that a pop-out phenomenon in which a growing silicon single crystal ingot is inadvertently separated from a silicon melt is likely to occur.

Accordingly, in the embodiment, when a silicon single crystal ingot is produced by the Czochralski method, a pop-out phenomenon in which a silicon single crystal ingot being grown in a tailing process is inadvertently separated from a silicon melt does not occur A large-diameter silicon monocrystal ingot growth method of 400 mm or more without occurrence of dislocation.

FIG. 2 is a view showing an example of a change in the melt gap according to the length of the tail portion in the single crystal ingot growing method in the embodiment and the prior art.

2, R2 is an example of a change in the melt gap according to the length of the tail portion when the crucible does not rise during the tailing process of the silicon single crystal ingot having a diameter of about 300 mm in the prior art (No Cricible Lift up) R1 is an example of the change of the melt gap according to the length of the tail portion when the crucible does not rise during the tailing process of the silicon single crystal ingot having a diameter of about 450 mm in the prior art (No Cricible Lift up).

On the other hand, P is an example of a change in the melt gap according to the length of the tail portion when the crucible rises (Cricible Lift up) during the tailing process of the silicon single crystal ingot having a diameter of about 450 mm in the manufacturing method of the single crystal ingot according to the embodiment to be.

According to the prior art, a silicon single crystal ingot growth of not more than 300 mm is generally conducted in a tailing process in a state where crucible rise is stopped during a tailing process (No Crucible Lift up).

On the other hand, a 450 mm single crystal ingot has a larger volume than a 300 mm single crystal. As a result, the height of the solid-liquid interface is increased due to the cooling driving force of the crystal due to the lowering of the melt level in the tailing process. There is a high possibility that a pop-out phenomenon in which a silicon single crystal ingot is inadvertently separated from a silicon melt.

3 is an exemplary photograph of a monocrystalline ingot popped out during a tailing process in a monocrystalline ingot according to the prior art.

In the body process in the production of the silicon single crystal, the crucible is lifted up so that the free surface of the silicon melt is at the same position, and the silicon single crystal is lowered Which compensates for the position of the Melt Free Surface.

Conventionally, when a silicon single crystal of 300 mm or less is grown, the potential generation rate in the tailing process is low. Thus, the tailing process is recognized as a process for separating a silicon melt and a silicon single crystal in a silicon single crystal process, A tailing process is performed as much as the diameter of the single crystal ingot.

However, in the production of large diameter silicon single crystals of 400 mm or more, there is a high probability that a pop-out phenomenon occurs in which the silicon single crystal is inadvertently separated from the silicon melt during the tailing process without raising the crucible in the tailing process.

In order to prevent a pop-out phenomenon, if the silicon single crystal pulling up rate is lowered during the tailing process, the reduction of the diameter of the crystal for the purpose of tailing progress can not be easily controlled. In order to decrease the crystal diameter at a low crystal pulling rate, , A vicious cycle occurs in which the possibility of pop-out is increased again.

If a pop-out occurs during the growth of a large-diameter silicon single crystal with a high liquid interface at a high temperature of 400 mm or more. If the circumferential portion of the bottom of the separated crystal contacts with the silicon melt again after the pop-out, cooling of the single crystal ingot In order to reduce the possibility of pop-out in the tailing process, it is necessary to compensate for the decrease in the cooling power of the crystal during the tailing process, while the silicon single crystal and the silicon melt A method of lowering the height of the interface between the solid and the liquid should be devised.

In FIG. 2, P is an example of the change in the melt gap according to the length of the tail portion when the crucible rises (Cricible Lift up) during the tailing process of the silicon single crystal ingot having a diameter of about 450 mm in the manufacturing method of the single crystal ingot according to the embodiment .

According to the embodiment, a full structure single crystal ingot as shown in FIG. 4 can be manufactured by controlling the melt gap to about 35 mm or less in the tailing process of a large diameter silicon single crystal ingot having a diameter of about 400 mm or more .

According to the embodiment, by controlling (A) the melt gap in the tailing process of the large diameter silicon single crystal ingot of about 400 mm in diameter or larger to about 35 mm or less, for example, 10 mm or less in the prior art from about 50 to 60 mm, Full Structure Single crystal ingot can be manufactured.

In addition, according to the embodiment, the length of the tail portion can be controlled to about 420 mm in the tailing process of a single crystal having a diameter of 450 mm, so that the tailing process time can be reduced and the yield can be improved as compared with the prior art.

Fig. 5 is an exemplary diagram illustrating changes in crucible lift according to the length of the tees in Examples and prior art. Fig.

As shown in FIG. 5, according to the prior art (RC), the tailing process was performed in a state where the crucible lifting was stopped (crucible lift ratio = 0) in the tailing process after the body process. On the other hand, according to the embodiment (PC), by applying the crucible rising in the tailing process, it is possible to improve the crystal growth cooling driving force to reduce the melt gap and reduce the height of the liquid interface to lower the possibility of pop- The production yield of the large diameter silicon single crystal can be increased by manufacturing a single crystal ingot.

FIG. 6 is a diagram illustrating an example of seed rotation change according to the length of the tees in the embodiment and the prior art.

As shown in FIG. 6, according to the conventional technology (RS), the seed rotation after the body process was kept constant in the tailing process. However, according to the embodiment (PS), the crucible- It is possible to further increase the production yield of the large-diameter silicon single crystal by effectively reducing the gap and effectively controlling the height of the solid-liquid interface.

For example, according to the embodiment, in order to lower the height of the solid-liquid interface during the tailing process, the seed rotation rate is gradually decreased so that the rotational speed of the stepped ingot is about 5 rpm or less when the length of the tail portion is 100 mm or more Through the tailing process, the production yield of large-diameter silicon single crystals can be further increased.

FIG. 7 is a diagram illustrating an example of a change in magnetic field according to a length of a tee in the embodiment and the prior art. FIG.

As shown in FIG. 7, according to the prior art RM, the magnetic field is kept constant in the tailing process after the body process. However, according to the embodiment PM, the magnetic field is gradually reduced by application of the crucible- It is possible to further increase the production yield of the large-diameter silicon single crystal by effectively reducing the gap and effectively controlling the height of the solid-liquid interface.

For example, according to the embodiment, in order to lower the height of the solid-liquid interface during the tailing process, the magnetic field is gradually decreased and the tailing process is performed at a magnetic field of about 1000 Gauss or less at a length of the tail portion of about 100 mm or more, The yield can be further increased.

The embodiments are directed to a silicon ingot which can improve the production yield of a large-diameter silicon single crystal ingot by reducing the possibility of pop-out in a tailing process of the silicon single crystal ingot by controlling the crucible rotation speed, controlling the seed turnover rate, A method of growing a single crystal ingot can be provided.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. It can be seen that the modification and application of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

100: single crystal growth apparatus, 110: chamber
112: crucible, 120: heater, 128: lifting means

Claims (7)

Melting polycrystalline silicon in a crucible and then conducting a necking process from a molten silicon melt using a single crystal seed;
A body processing step of growing a single crystal ingot in the radial direction of the seed and advancing the body after advancing the shoulder so as to have a predetermined diameter; And
And a tailing process of reducing the diameter of the body and separating the silicon melt from the silicon melt,
The diameter of the body portion of the single crystal ingot is 400 mm or more,
Wherein the melt gap is controlled to 35 mm or less when the tailing process is performed. The method according to claim 1,
And growing the crucible upon progressing the tailing process. 3. The method of claim 2,
And controlling the melt gap to be 10 mm or less in the tailing process. 3. The method of claim 2,
Wherein the seed rotating speed is lowered while applying a crucible upward in the tailing process. 5. The method of claim 4,
Wherein the seed rotating speed is gradually decreased, and after the length of the tail portion grown in the tailing process exceeds 100 mm, the remaining tailing process is performed at 5 rpm or less. 3. The method of claim 2,
And a magnetic field is gradually reduced together with application of a crucible in the tailing process. The method according to claim 6,
Wherein the magnetic field is gradually decreased in the tailing step, and a tailing process is performed in a magnetic field of 1000 Gauss or less at a length of 100 mm or less after the tail portion.

Images