KR101193786B1 - Single Crystal Grower, Manufacturing Method for Single Crystal, and Single Crystal Ingot Manufacturied by the same - Google Patents

Abstract

Embodiments relate to a single crystal growing apparatus, a single crystal growing method, and a single crystal ingot grown thereby.
The single crystal growth apparatus according to the embodiment includes a crucible capable of containing a melt and a magnet spaced apart from the crucible and installed around the crucible, wherein the melt changes according to the growth of the single crystal ingot. The position of the magnet may be controlled according to the remaining volume ratio α.

Description

Single Crystal Grower, Single Crystal Growth Method, and Single Crystal Ingot Grown by the Single Crystal Grower, Manufacturing Method for Single Crystal, and Single Crystal Ingot Manufacturied by the same

Embodiments relate to a single crystal growing apparatus, a single crystal growing method, and a single crystal ingot grown thereby.

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 the wafer, first, single crystal silicon needs to be grown in an ingot form, and for this, Czochralski (CZ) method may be applied.

Currently, quartz crucibles are used to contain molten silicon melt in a single crystal ingot manufacturing method by the CZ method. These quartz crucibles are dissolved in the melt together with the reaction with the silicon melt to be transformed into SiOx form, which is incorporated into the ingot to form micro internal defects (BMD) or the like to act as gettering sites for metal impurities during the semiconductor process, On the other hand, by causing various defects and segregation, it can eventually adversely affect the yield of the semiconductor device.

In order to control the oxygen concentration in the single crystal ingot, there is a method of changing the hot zone (H / Z) in the crystal growth furnace substantially. For example, the method of controlling the dissolution rate of a quartz crucible by adjusting the length of a heater, a slit, etc. has been discussed a lot.

In addition, there is a method of controlling the oxygen concentration by adjusting the rotation speed of the single crystal ingot, the rotation speed of the quartz crucible, the argon or the pressure in the growth furnace, and the like.

Another method is to control the oxygen concentration through melt convection using a magnetic field.

On the other hand, despite the conventional technology, there is a weak technique for controlling the oxygen concentration variation in the crystal length direction and the wafer in-plane oxygen concentration variation in the low oxygen concentration.

In addition, the prior art does not propose a technique for reducing the dispersion by relatively controlling the oxygen concentration in the in-plane center portion and the edge portion of the wafer.

Embodiments provide a single crystal growth apparatus, a single crystal growth method, and a single crystal ingot grown thereby, which can effectively control low oxygen, crystal length direction, and in-plane oxygen variation.

The single crystal growth apparatus according to the embodiment includes a crucible capable of containing a melt and a magnet spaced apart from the crucible and installed around the crucible, wherein the melt changes according to the growth of the single crystal ingot. The position of the magnet may be controlled according to the remaining volume ratio α.

In addition, the single crystal growth method according to the embodiment of the present invention comprises a crucible capable of containing a melt and a magnet spaced apart from the crucible and installed around the crucible, wherein the melt changes according to the growth of the single crystal ingot. (Melt) The position of the magnet may be controlled according to the remaining volume ratio α.

In addition, the single crystal ingot according to the embodiment is manufactured by the single crystal growth method described above, wherein ORG (Oxygen Radial Gradient) in the cross section of the plane direction perpendicular to the axial direction is ORG = (Maximum Oi-Minimum Oi) / (Maximum Oi) If indicated by ORG value may be configured to 4% or less.

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According to the single crystal growth apparatus, the single crystal growth method, and the single crystal ingot and the wafer grown by the embodiment, no additional measures such as hot zone (H / Z) replacement for various levels of oxygen concentration control in the prior art are unnecessary.

In addition, according to the embodiment, when the remaining volume of the melt is separated at a specific ratio by using a magnetic field during the single crystal ingot growth process, low oxygen is realized and the crystal length direction and wafer are made using a method that facilitates oxygen distribution control. In-plane oxygen deviation can be effectively controlled.

For example, the location of the magnet is determined by setting the melt remaining volume ratio to 0.3 to 0.6. As the length of the single crystal increases, the position of the MGP gradually increases from the initial center to the surface of the melt. There is a characteristic that is controlled while rising, it can be used to effectively control the implementation of low oxygen, the crystal length direction and the oxygen deviation in the wafer (Wafer) plane.

In particular, the embodiment can significantly control the in-plane oxygen concentration variation, which is a disadvantage of low oxygen concentration wafers.

1 is a schematic view of a single crystal growth apparatus according to the embodiment.
Figure 2 is an illustration of a method for growing a single crystal while maintaining a specific ratio of the total volume of the remaining melt (Melt) Vt and the melt volume Va in the upper portion of the MGP position by applying the single crystal growth apparatus according to the embodiment.
3 to 6 is a result of the behavior of the oxygen concentration carried out by moving the magnet position using the volume ratio of the remaining melt during silicon single crystal ingot growth according to the embodiment.
7 is a result of the behavior of oxygen concentration carried out by moving the magnet position to the melt surface using the volume ratio of the remaining melt as the silicon single crystal ingot grows according to the embodiment.
8 is an in-plane oxygen concentration deviation performed by moving the magnet position to the melt surface using the volume ratio of the remaining melt during silicon single crystal ingot growth according to the embodiment.
9 is a ratio diagram when converted to Ha / Ht when Va / Vt behaves at 0.3 to 0.6 during silicon single crystal ingot growth according to an embodiment.

Hereinafter, a single crystal growth apparatus, a single crystal growth method, and a single crystal ingot and a wafer grown by the same will be described in detail with reference to the accompanying drawings.

(Example)

The embodiment relates to a method of controlling the oxygen concentration by adjusting the MGP (Maximum Gauss Position) position in a method of controlling oxygen concentration by inhibiting dissolution of a quartz crucible using a horizontal type magnet (Horizontal type magnet). will be. Here, MGP means the distance from the free surface of the melt to the center of the horizontal magnetic field.

When the MGP is located near the ingot interface, the power of the heater is relatively increased. At this time, the oxygen concentration is increased, and when it is far away, the oxygen concentration is decreased. This is a method of controlling the amount of oxygen eluted from the quartz crucible with a magnetic field.

However, as the ingot grows, the magnet's relative position changes and the amount of melt decreases, causing the melt convection and the thermal environment to change. Due to this effect, there is a problem that the oxygen concentration deviation and the oxygen concentration deviation in the wafer surface in the crystal length direction are deteriorated, and there is a limit to the oxygen concentration control by simply moving the magnet.

The use of a strong magnetic field, especially in low oxygen concentration implementations, reduces the smooth mixing of the melt convection, thus increasing the in-plane oxygen concentration dispersion. In the case of in-plane oxygen concentration deviation, it can be expressed by ORG (Oxygen Radial Gradient), which is the following Equation 1, and means the ratio of the oxygen concentration deviation to the maximum oxygen concentration in the wafer plane.

In Equation 1, the case of low oxygen shows a higher ORG even in the case of the same in-plane oxygen concentration deviation than in the case of high oxygen. That is, when the in-plane oxygen concentration deviations are the same (when the molecules are the same in Equation 1), in case of low oxygen than high oxygen (the value of the molecule is high in oxygen and low in oxygen in Equation 1), the ORG value increases. .

Accordingly, an embodiment provides a single crystal growth apparatus, a single crystal growth method, and a single crystal ingot and a wafer grown thereby, which can implement low oxygen and effectively control the ingot crystal length direction and in-plane oxygen variation.

In addition, the embodiment is intended to significantly control the variation in the oxygen concentration in the wafer surface, which is a disadvantage of the low oxygen concentration wafer (Wafer).

1 is a schematic diagram of a single crystal growth apparatus 100 according to an embodiment.

In order to solve the above problem, the convection of a melt close to the wall of the crucible 110 by applying a low magnetic flux to a crucible 110, for example, a quartz crucible, using a strong magnetic field during the single crystal ingot growth process. In the suppressed state, the position of the magnet (Magnet) 120 can be positioned at a value calculated by a specific volume ratio to control the oxygen concentration variation in the crystal length direction of the ingot. In particular, it is intended to present a method capable of uniformly controlling the in-plane oxygen concentration.

In FIG. 1, Ha is a distance calculation value from the melt surface to the MGP, and Ht is a distance calculation value from the melt surface to the bottom of the crucible.

FIG. 2 illustrates a method of growing a single crystal while maintaining the specific volume of Vt and the volume of melt on the upper portion of the MGP position by applying the single crystal growing apparatus 100 according to the embodiment. It is an illustration.

The embodiment applies a magnetic field of about 3000 Gauss or more to suppress convection of the melt (Melt) near the wall of the crucible 110, and controls the crucible 110 rotation to 0.2 RPM or less, but is not limited thereto.

In the embodiment, the initial MGP was set at a ratio of Va / Vt of 0.3 to 0.6. As the ingot IG grows, the relative position of the magnet 120 changes and the amount of the melt decreases, so that the melt convection changes. In this condition, the ingot was grown while moving the magnet 120 to reduce the in-plane oxygen concentration variation. As a result, the oxygen concentration of the sensor center and the edge of the wafer was changed according to the moving speed of the magnet 120 by length. .

In an exemplary embodiment, the position Mp of the magnet 120 may be converted into a specific volume ratio α of the remaining melt Melt and positioned at the position of Equation 2 below.

At this time, Co is the initial position of the crucible, Cj is the position of the crucible when the length of the single crystal ingot is j, V [X] is when the distance from the bottom of the crucible to the melt surface by x Total Melt Remaining volume (i.e. remaining volume of melt when length of single crystal ingot is j), α is the ratio of Va to Vt (Va / Vt), Vt is the total remaining volume of melt, and Va Is the remaining volume of the melt that is above the MGP position, and F (x) is the distance calculation value Ha from the melt surface at the x volume to the MGP.

3 to 6 are results of behavior of oxygen concentration performed by moving a magnet position using a volume ratio of remaining melt during silicon single crystal ingot growth according to an embodiment.

For example, FIG. 2 is performed by changing a magnet moving speed during a process of growing a 300 mm silicon single crystal ingot for a wafer having low oxygen concentration with improved in-plane scattering using a horizontal magnet. It is the result of behavior of oxygen concentration.

Specifically, FIG. 3 is a case where the α value which is a ratio value of Va and Vt is set as a decreasing function, FIG. 4 is a case where α value which is a ratio value of Va and Vt is 0.3, and FIG. 5 is a ratio of Va and Vt. The value α is 0.6, and FIG. 6 is a case where the value α is an increase function.

According to the embodiment, the experiment after setting the α value, which is the ratio of Va and Vt to a constant of 0.3 to 0.6, improved the oxygen concentration distribution in the wafer surface, but when the α value was set as an increasing function, the edge The oxygen concentration in the center of the sensor was lower than the oxygen concentration in. When the α value was set as a decreasing function, the oxygen concentration in the center was higher than the oxygen concentration at the edge.

7 is a result of the behavior of the oxygen concentration carried out by moving the magnet position to the melt surface using the volume ratio of the remaining melt as the silicon single crystal ingot grows according to the embodiment.

According to the results of FIG. 7, the data is " center oxygen concentration, edge 4 point oxygen concentration value " and when the α value is a constant value of 0.3 to 0.6, the oxygen concentration deviation is small, and when the α value is set as a decreasing function, the edge The oxygen concentration in the center was higher than the oxygen concentration in. When the α value was set as an increase function, the oxygen concentration in the center was lower than the oxygen concentration at the edge.

8 is an in-plane oxygen concentration variation performed by moving a magnet position to a melt surface by using a volume ratio of remaining melt during silicon single crystal ingot growth according to an embodiment.

According to FIG. 8, the in-plane oxygen concentration distribution is uniform when α, which is a ratio value of Va and Vt, is a constant value of 0.3 to 0.6. For example, the ORG value may be 4 or less.

On the other hand, the in-plane oxygen concentration distribution tends to deteriorate when the ratio value of Va and Vt is out of the above range or when the α value is an increase function or a decrease function condition which is not a constant.

FIG. 9 is a ratio chart when converting to Ha / Ht when Va / Vt behaves at 0.3 to 0.6 during silicon single crystal ingot growth.

According to FIG. 9, when Va / Vt behaves at 0.3 to 0.6, the ratio is not fixed in terms of Ha / Ht and the ratio decreases as the length of the single crystal increases, and the rate decrease accelerates toward the latter part of the ingot body and the position of the magnetic field. Can be controlled while accelerating and moving from the initial position to the melt surface.

According to the embodiment, during the single crystal ingot growth process, when the remaining volume of the melt is separated at a specific ratio by using a magnetic field, it is easy to control the oxygen distribution, and to realize low oxygen, crystal length direction, and oxygen in the wafer surface. Deviation can be effectively controlled.

For example, the location of the magnet is determined by setting the melt remaining volume ratio to 0.3 to 0.6. As the length of the single crystal increases, the position of the MGP gradually increases from the initial center to the surface of the melt. There is a characteristic that is controlled while rising, it can be used to effectively control the implementation of low oxygen, the crystal length direction and the oxygen deviation in the wafer (Wafer) plane.

In particular, the embodiment can significantly control the in-plane oxygen concentration variation, which is a disadvantage of low oxygen concentration wafers.

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 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.

In addition, the above description has been made with reference to the embodiments, which are merely examples and are not intended to limit the embodiments, and those skilled in the art to which the embodiments belong may not be exemplified above without departing from the essential characteristics of the embodiments. It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. 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 (12)

In the single crystal growth apparatus comprising a crucible capable of containing a melt and a magnet spaced apart from the crucible and installed around the crucible,
A single crystal growth apparatus in which the position of the magnet is controlled according to the melt remaining volume ratio (α) which changes according to the growth of the single crystal ingot. The method according to claim 1,
The location of the magnet is determined by setting the melt remaining volume ratio α to 0.3 to 0.6,
wherein α = Va / Vt, Vt is the total remaining volume of the melt, and Va is the remaining volume of the melt above the Maximum Gauss Position (MGP). The method according to claim 1,
The single crystal growth apparatus is controlled as the position of the MGP gradually rises from the center of the melt to the surface of the melt (Melt) as the length of the single crystal increases during the growth of the single crystal ingot. In the single crystal growth apparatus comprising a crucible capable of containing a melt and a magnet spaced apart from the crucible and installed around the crucible,
A method of growing a single crystal in which a magnet is controlled in accordance with a melt remaining volume ratio (α), which changes according to the growth of a single crystal ingot. 5. The method of claim 4,
The location of the magnet is determined by setting the melt remaining volume ratio α to 0.3 to 0.6,
wherein α = Va / Vt, Vt is the total remaining volume of the melt, and Va is the remaining volume of the melt above the Maximum Gauss Position (MGP). 5. The method of claim 4,
Single crystal growth method is controlled as the position of the MGP gradually increases from the center to the surface of the melt (Melt) as the length of the single crystal increases during the growth of the single crystal ingot. delete delete delete Prepared by the method of any one of claims 4 to 6,
ORG (Oxygen Radial Gradient) in the cross section in the plane direction perpendicular to the axial direction,
If ORG = (Maximum Oi-Minimum Oi) / (Maximum Oi) is displayed,
Monocrystalline ingot with ORG value less than 4%. delete delete

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