KR101129928B1 - Method for Manufacturing Single Crystal - Google Patents

Abstract

The example relates to a single crystal production method.
In one embodiment, a method of manufacturing a single crystal includes loading polycrystalline silicon into a quartz crucible of a chamber and heating the same using a heater to form a silicon melt; And injecting a dopant into the silicon melt using a dopant injector, wherein the injecting the dopant is performed at a power of 2 KW or more than a dip power of a chamber for forming the silicon melt. Injection may proceed.

Description

Method for Manufacturing Single Crystal

The example relates to a single crystal production method.

In order to manufacture a semiconductor, a process of manufacturing a wafer, injecting predetermined ions into the wafer, and forming a circuit pattern is required. In this case, in order to manufacture a wafer, first, single crystal silicon must be grown in an ingot form, and for this, a Czochralski (CZ) method or a floating zone (FZ) method may be applied.

Czochralski (CZ) method is a method of growing a crystal while immersing a seed crystal (seed crystal) in molten silicon and slowly pulling it up. According to this method, first, a necking process of growing thin and long crystals from seed crystals is carried out, followed by a shouldering process of growing crystals in a radial direction to a target diameter, and then a constant diameter. After the body growing process to grow into a crystal having a certain length, after the body growing by a certain length, the single crystal growth is finished through a tailing process that gradually decreases the diameter of the crystal and finally separates it from the molten silicon. do.

In general, silicon wafers used as substrates for semiconductor devices have a P-type or N-type dopant added in the growth process of silicon single crystals in order to have an appropriate resistivity value.

In addition, the P-type or N-type dopant is further divided into a high melting point dopant having a higher melting point than a melting point of silicon and a low melting point dopant having a lower melting point than that of a silicon. The dopant is added to the silicon melt according to the type of dopant. The way is different.

A typical P-type high melting point dopant is boron (B), and its melting point is about 2180 ° C., which is higher than the melting point of silicon 1414 ° C., so that polycrystalline silicon, which is a silicon single crystal growth preparation step, is loaded into a quartz crucible. It is possible to add dopants to the silicon melt by injecting and melting together with polycrystalline silicon in the bottom of the quartz crucible.

On the other hand, low melting point dopants having lower melting point than silicon include antimony (Sb), red (Red Phosphorus), germanium (Ge), arsenic (As), etc. These low melting dopants are due to the low melting point In the melting stage of the first polycrystalline silicon during the single crystal growth process, the polycrystalline silicon is melted and vaporized before it is completely melted.

The vaporized low melting point dopant is discharged to the outside of the growth furnace with an inert gas such as Ar flowing to remove the silicon oxide causing contamination in the silicon growth furnace. It would not be possible to produce the silicon single crystals added.

Accordingly, in order to inject high concentrations of low melting point dopants, polycrystalline silicon has been completely dissolved and then powdered low melting point dopants are sprayed onto the surface of the molten silicon to perform doping. However, at this time, the temperature of the silicon melt is so high that the dopant does not completely melt into the silicon melt, and about 30% of it is vaporized to be discharged and removed outside the single crystal growth apparatus together with the inert gas.

Therefore, even in this case, control of the injection concentration of the low melting point dopant is incomplete, and waste of the low melting point dopant is generated. In addition, most of the low melting point dopants have a problem of causing environmental pollution when discharged to the outside of the growth furnace as a toxic substance.

In particular, oxides are generated due to impurities in the low melting dopant, and these oxides float on the surface of the silicon melt, causing particle hits, and making silicon single crystal growth impossible, thereby causing a fatal cause of lowering silicon single crystal productivity. do.

On the other hand, according to the prior art, there is a limit to the method of measuring the degree of contamination in the chamber of the single crystal growth apparatus.

Embodiments provide a single crystal manufacturing method capable of preventing contamination of a silicon melt by a low melting point dopant.

In addition, the embodiment is to provide a method that can easily and accurately measure the degree of contamination in the chamber.

In one embodiment, a method of manufacturing a single crystal includes loading polycrystalline silicon into a quartz crucible of a chamber and heating the same using a heater to form a silicon melt; And injecting a dopant into the silicon melt using a dopant injector, wherein the injecting the dopant is performed at a power of 2 KW or more than a dip power of a chamber forming the silicon melt. Injection may proceed.

According to the single crystal manufacturing method according to the embodiment, the doping process is injected by adjusting the doping process conditions of the low melting point dopant to prevent contamination of the silicon melt by the low melting point dopant, and the loss caused by the contamination of the single crystal Can be prevented.

In addition, according to the embodiment, the degree of contamination in the chamber can be easily and accurately measured.

1 is an illustration of a single crystal growth apparatus to which the method for producing a single crystal according to the embodiment is applied.
2 is an experimental example and a comparative example measured by using the weight of the contamination degree in the chamber in the method for producing a single crystal according to the embodiment.
Figure 3 is an illustration of the loss point in the shoulder of the single crystal in the case of applying the method of producing a single crystal according to the embodiment and a comparative example.
Fig. 4 is an illustration of the loss point of the single crystal in the body when the manufacturing method of the single crystal according to the embodiment is applied and in the comparative example.

Hereinafter, a single crystal manufacturing method according to an embodiment will be described in detail with reference to the accompanying drawings.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under" the substrate, each layer Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

(Example)

1 is an exemplary view of a single crystal growth apparatus to which a method for manufacturing a single crystal according to an embodiment is applied.

The silicon single crystal growth apparatus 100 according to the embodiment may include a chamber 110, a crucible 120, a heater 130, a dopant injection device 160, and the like.

For example, the single crystal growth apparatus 100 according to the embodiment is provided in the chamber 110, the inside of the chamber 110, the crucible 120 containing the silicon melt, and the inside of the chamber 110. Is provided in, may include a heater 130 for heating the crucible 120 and a dopant injection device 160 for injecting a dopant into the silicon melt (SM).

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

The radiant heat insulator 140 may be installed on the inner wall of the chamber 110 to prevent heat of the heater 130 from being discharged to the side wall of the chamber 110.

The embodiment may control various factors such as the rotational speed of the quartz crucible 120 and the pressure conditions inside the chamber to control the oxygen concentration during silicon single crystal growth. For example, in order to control the oxygen concentration, an argon gas or the like may be injected into the chamber 110 of the silicon single crystal growth apparatus and discharged downward.

The crucible 120 is provided inside the chamber 110 to contain the silicon melt SM and may be made of quartz. A crucible support 125 made of graphite may be provided outside the crucible 120 to support the crucible 120. The crucible support 125 is fixedly installed on the rotation shaft 127, which is rotated by a driving means (not shown) so that the solid-liquid interface has the same height while rotating and elevating the crucible 120. It can be maintained.

The heater 130 may be provided inside the chamber 110 to heat the crucible 120. For example, the heater 130 may have a cylindrical shape surrounding the crucible support 125. The heater 130 melts a high-purity polycrystalline silicon mass loaded in the crucible 120 into a silicon melt SM.

The dopant injection device 160 may be connected to the seed chuck 152 of the single crystal growth lifter 150 to perform a dopant injection process.

In an embodiment, the dopant D may be, but is not limited to, antimony (Sb), red (Red Phosphorus), germanium (Ge), arsenic (As), and the like.

The lower end of the dopant injector 160 is dipped in the silicon melt SM while the dopant D is loaded in the dopant injector 160 so that the dopant D is in contact with the silicon melt SM. The dopant D may be melted and vaporized by the temperature of the silicon melt SM, but is not limited thereto.

For example, the lower end of the dopant injector 160 is to be contained in the silicon melt SM, but the dopant D is loaded in a predetermined dopant receiver (not shown) so as not to be in direct contact with the silicon melt SM. In order to be supplied with heat from the silicon melt (SM) by radiation rather than conduction, the low melting point dopant (D) can be vaporized in a gaseous state, the vaporized gaseous low melting point dopant (D) is a dopant injection device ( Through the through-hole (not shown) formed at the bottom of the 160, the gaseous low melting point dopant may be injected into the silicon melt (SM).

In the embodiment, the method of injecting the dopant D into the silicon melt SM is not limited to the dopant injection method using the dopant injection device 160 described above.

According to the single crystal manufacturing method according to the embodiment, it is possible to prevent contamination of the silicon melt by the low melting point dopant by adjusting the doping process conditions of the low melting point dopant.

For example, injecting the dopant D into the silicon melt SM using the dopant injector 160 may include a dip power of the chamber 110 forming the silicon melt SM. Dopants may be implanted at more than about 2 KW power.

In an embodiment, the dip power of the chamber 110 forming the silicon melt SM may be the power of the heater 130 to a temperature at which the polycrystalline silicon is melted.

According to the single crystal manufacturing method according to the embodiment, the doping process conditions of the low-melting point dopant by the dopant is injected at a power of about 2 KW or more than the dip power of the chamber forming the silicon melt by the low-melting point dopant Contamination of the silicon melt can be prevented, so that loss due to contamination of the single crystal can be prevented.

2 is a test example (Case 4) and a comparative example (Case 1, Case 2, Case 3) measured by using the difference in weight of the contamination in the chamber in the method of manufacturing a single crystal according to the embodiment.

Case pressure Dip power Doping time
Comparative example Case 1 80 Torr or more Dip power + 1KW or less More than 15 minutes-less than 20 minutes Case 2 50 ~ 80 Torr Dip power + 1KW and above 2 KW More than 15 minutes-less than 20 minutes Case 3 50 Torr or less Dip power + 1KW and above 2 KW More than 15 minutes-less than 20 minutes Example Case 4 50 Torr or less Dip power + 2KW or more 15 minutes or less

Table 1 is an example of the process conditions in the case of applying a single crystal manufacturing method according to the embodiment (Case 4) and Comparative Examples (Case 1, Case 2, Case 3).

In the method of manufacturing a single crystal according to the embodiment, the degree of contamination in the chamber may be measured, and thus the degree of contamination may be easily measured by measuring a weight difference with respect to a specific area of the chamber as shown in FIG. 2. For example, after the dopant implantation process, the degree of contamination in the chamber can be easily measured by measuring a weight difference between a lower portion of the chamber in which the crucible 120 is positioned and a barrier layer (not shown) disposed at a boundary between the upper portion of the chamber in which the single crystal growth lifter 150 is located. Although it can measure, the contamination measurement object is not limited to this. On the other hand, in the case of measuring the contamination level using the barrier film, the weight difference may be measured after wiping off contaminants such as particles that are not fixed on the barrier film, but is not limited thereto.

According to the embodiment, the pollution degree can be easily measured by the pollution degree measuring method using the weight difference, and the measurement results are the results of the measurement results of the contamination levels in the grown single crystals described below with reference to the results of FIGS. 3 and 4. It can be seen that the concordance, the method of measuring the contamination level of the chamber using the weight difference according to the embodiment can be seen that it is very useful for the contamination measurement.

FIG. 3 is a diagram illustrating a diameter-based loss point (%) at the shoulder of the single crystal in the comparative example and when the manufacturing method of the single crystal according to the embodiment is applied, and FIG. Fig. 1 shows examples of the loss point (%) of the body of the single crystal in the case where the method for producing a single crystal is applied and in the comparative example.

In FIGS. 3 and 4, the test for each case is repeated five times to analyze the data for the loss point, and it can be seen that the embodiment (Case4) has the best gain (%).

Hereinafter, the loss point (%) analysis data for the Examples and Comparative Examples.

First, in case 1 of the comparative example, the contamination in the chamber was the most severe when compared with other examples, Case 2, Case 3, and Case 4. Accordingly, the contamination level of Case 1 is shown as 100% in FIG. 2.

Meanwhile, in case 1, polycrystallization occurred at a level of about 31.6% or more based on the diameter of the shoulder of the single crystal grown as shown in FIG. 3, and particles contaminated at about 40% or more based on the body growth length as shown in FIG. 4. Polycrystallization by occurred.

In addition, there was a problem that further doping further accelerates the location of contamination and polycrystallization in the chamber. For example, there was a problem in that the location of contamination and polycrystallization in the chamber is advanced to the level of about 50% or less based on the diameter of the shoulder and about 31.6% or less based on the body growth length by additional doping.

Case 2 had a second level (about 75%) of contamination in the chamber compared to Case 1, Case 3, and Case 4 as shown in FIG.

In addition, polycrystallization occurred at a level of about 61.8% or more based on the diameter of the shoulder of the single crystal grown as shown in FIG. 3, and polycrystal due to contaminated particles at about 51.6% or more based on the body growth length as illustrated in FIG. 4. Upset occurred. In addition, there is a problem that the location of such internal contamination and polycrystallization by the additional doping is also advanced.

Case 3 had a third level (about 45%) of contamination in the chamber compared to Case 1, Case 2, and Case 4 as shown in FIG.

In addition, polycrystallization occurred at a level of about 75% or more based on the diameter of the shoulder of the single crystal grown as shown in FIG. 3, and polycrystal due to contaminated particles at about 72% or more based on the body growth length as shown in FIG. 4. Upset occurred. On the other hand, there was no significant change in the location of contamination and polycrystallization in the chamber when there was additional doping.

Case 4, which is an example, was the lowest level (about 25%) in the chamber when compared to Case 1, Case 2 and Case 3, which are comparative examples as shown in FIG.

In addition, polycrystallization occurred at a level of about 96% or more based on the diameter of the shoulder of the single crystal grown as shown in FIG. 3, and polycrystal due to contaminated particles at about 96.8% or more based on the body growth length as shown in FIG. 4. Upset occurred. On the other hand, the contamination level was the lowest even with additional doping.

According to the single crystal production method according to the embodiment, it is possible to prevent contamination of the silicon melt by the low melting point dopant by adjusting the doping process conditions of the low melting point dopant.

According to the single crystal manufacturing method according to the embodiment, the doping process conditions of the low-melting point dopant by the dopant is injected at a power of about 2 KW or more than the dip power of the chamber forming the silicon melt by the low-melting point dopant Contamination of the silicon melt can be prevented, so that loss due to contamination of the single crystal can be prevented.

In addition, according to the embodiment, the degree of contamination in the chamber can be easily and accurately measured.

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 each embodiment may be combined or modified with respect to other embodiments by those 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 embodiment can be modified. And differences relating to these modifications and applications will have to be construed as being included in the scope of the embodiments defined in the appended claims.

Claims (6)

Stacking polycrystalline silicon in a quartz crucible of the chamber and heating with a heater to form a silicon melt; And
Injecting a dopant into the silicon melt using a dopant injector;
Injecting the dopant
And a dopant is injected at a power of 2 KW or more than a dip power of the chamber forming the silicon melt. The method according to claim 1,
The dip power of the chamber forming the silicon melt is
A method for producing a single crystal, which is the power of a heater to a temperature at which the polycrystalline silicon is melted. The method according to claim 1,
In the step of injecting the dopant,
The time for injecting the dopant is less than 15 minutes manufacturing method of a single crystal. The method according to claim 1,
Injecting the dopant,
Ar is 50lpm (liters per minute) or more, pressure is 50 Torr or less, dopant injection time is less than 15 minutes. The method according to claim 1,
After injecting the dopant,
And measuring the contamination degree in the chamber by measuring the difference in weight of the contamination level in the chamber with respect to a predetermined region of the chamber. The method of claim 5,
In order to measure the degree of contamination in the chamber,
The method of manufacturing a single crystal for measuring the difference in weight of the barrier film is installed at the boundary between the lower chamber of the crucible and the upper chamber of the single crystal growth lifter.

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