KR100793950B1 - Silicon single crystal ingot and manufacturing method thereof - Google Patents

Abstract

A silicon single crystal ingot and a growing method thereof are disclosed. The disclosed silicon single crystal ingot growing method is a method of manufacturing a silicon single crystal using a magnetic field applied by a coil arranged on the outer side of a silicon single crystal growing apparatus for pulling up single crystals from a silicon melt by a Czochralski (CZ) method Wherein ZGP (Zero Gauss Plane) is positioned above the surface of the silicon melt by controlling the ratio and intensity of the magnetic field applied by the coil.

According to the present invention, in the Czochralski method for manufacturing not only a small-diameter but also a large-diameter single crystal having a diameter of 200 mm or more, various levels of oxygen concentration required through asymmetric magnetic field control are added to the crystal lengths without loss such as additional hot zone (H / There is an advantage that the oxygen concentration can be controlled in a uniform distribution in the direction of the oxygen concentration.

ZGP (Zero Gauss Plane), single crystal, wafer

Description

TECHNICAL FIELD [0001] The present invention relates to a silicon single crystal ingot and a method of growing the same. BACKGROUND ART [0002]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a structure of a silicon single crystal growing apparatus to which a silicon single crystal growing method according to the present invention is applied. FIG.

2 is a graph comparing the oxygen concentration homogeneity obtained by the silicon single crystal growth method according to the present invention with the conventional one.

3 is a graph showing the oxygen concentration control profile by the silicon single crystal growth method according to the present invention.

FIG. 4 is a graph showing the levels of oxygen concentration according to various asymmetric magnetic field ratios in a silicon single crystal growth method according to the present invention and quantitative values of oxygen concentration levels according to a magnetic field ratio. FIG.

FIG. 5 is a table and graph showing the level of oxygen concentration according to the magnetic field strength and a quantitative value of the oxygen concentration level according to the magnetic field intensity in the same method of growing the silicon single crystal according to the present invention Mark shown.

Description of the Related Art

10. Ingot

11. Crucible

12. Silicon melt (SM)

13. Support

14. Heater

15. Insulation

16. Lower coil

17. Upper coil

18. Thermal Shield

19. Rotary shaft

The present invention relates to a method of growing a silicon single crystal, and more particularly, to a method of growing a silicon single crystal by changing a hot zone (H / Z) composed of various components including a heater and a thermal insulation structure in a silicon single crystal growing apparatus To a silicon single crystal growth method capable of controlling oxygen concentration only by controlling a magnetic field ratio (Ratio) and an intensity without changing a parameter or a parameter.

Currently, a silica crucible has been essentially used to contain molten silicon melt in the single crystal growth method by the Czochralski (CZ) method. This silica crucible is dissolved in the melt accompanied by the reaction with the silicon melt, so that the silica crucible is transferred into the form of SiOx and eventually mixed into the single crystal. On the one hand, the silica crucible is strengthened by increasing the strength of the wafer and the bulk micro defect (Metal impurity) in a semiconductor process, and on the other hand, various defects and segregation are caused in the semiconductor process, resulting in an adverse effect on the yield of the semiconductor device .

 To control the oxygen concentration in such crystals, attempts have been made to design a substantial portion of the hot zone (H / Z) portion in the crystal growth furnace.

For example, attempts have been made to control the dissolution rate of the silica crucible by adjusting the length of a heater, power supplied by upper and lower thermal insulation, and the like.

However, this method causes problems such as the time and cost of replacing the hot zone (H / Z) every time according to various oxygen demand levels of the customer.

In order to solve the above-mentioned problems, recently, a magnetic field such as a cusp and a superconducting horizontal magnetic field is used to control the convection of the silicon melt or to strengthen the magnetic field applied to the inside of the crucible, There is a lot of attempts to reduce it.

For example, in the case of a cusp magnetic field, a method of moving a ZGP (Zero Gauss Plane) position around a crucible using a magnet member, or making the ZGP uniform or coincident with a surface of a silicon melt have. And researches such as inhibiting the oxygen dissolution inside the crucible by stabilizing the melt convection by using the high magnetic field through the superconducting horizontal magnetic field have been actively carried out.

However, such a method also requires the use of an additional member, or the superconducting magnet to be used is expensive, and the capacity of the equipment is increased. In addition, the ZGP operation of the cusp magnetic field under the melt for the control of the conventional melt convection is limited to the depth direction only in the top-bottom symmetrical shape or on the melt surface, In addition, a required oxygen concentration level or higher was obtained, which resulted in a decrease in productivity.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method of manufacturing a honeycomb structure by positioning a ZGP position on a surface of a melt without replacing an additional hot zone (H / Z) And controlling the oxygen concentration uniformly distributed in the longitudinal direction of the single crystal regardless of the length of the single crystal depending on the diameter and the charge size, thereby improving the productivity.

According to another aspect of the present invention, there is provided a method of growing a silicon single crystal by a Czochralski (CZ) method, the method comprising the steps of: Wherein a ZGP (Zero Gauss Plane) is positioned above the surface of the silicon melt by controlling the ratio and intensity of a magnetic field applied by the coil, in a method of manufacturing a silicon single crystal using a magnetic field.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram schematically showing a structure of a crystal growth apparatus to which a silicon single crystal growth method according to the present invention is applied.

First, prior to describing the silicon single crystal growth method according to the present invention, a silicon single crystal growth apparatus to which the silicon single crystal growth method according to the present invention is applied will be described.

A silicon single crystal growth apparatus as shown in Fig. 1 is used to grow a silicon single crystal ingot according to the Czochralski (CZ) method.

As shown in Fig. 1, a silicon single crystal growth apparatus includes a chamber (not shown) in which a silicon monocrystalline ingot 10 is grown.

A crucible 11 for containing a silicon melt (SM) 12 made of quartz is provided in the chamber. Outside the crucible 11, a support base 13, which is made of graphite and supports the crucible 11, (11).

The support base 13 is fixed on the rotary shaft 19. The rotary shaft 19 is rotated by a driving means (not shown) so that the crucible 11 is rotated while being elevated so that the high- . The support member 13 is surrounded by a cylindrical heater 14 at a predetermined interval, and the heater 14 is surrounded by a thermal insulating material 15.

The heater 14 melts a high-purity polycrystalline silicon ingot placed in the crucible 11 into a silicon melt 12. The heat retaining material 15 is formed in such a manner that the heat radiated from the heater 14 is diffused Thereby improving the thermal efficiency.

A lifting means (not shown) for lifting the cable by winding a cable is provided above the chamber above the crucible 11. The lower part of the cable is brought into contact with the silicon melt 12 in the crucible 11, A seed crystal for growing the single crystal ingot 10 is provided. The silicon single crystal ingot 10 is rotated about the same axis as the rotation axis 19 of the crucible 11 by rotating the crucible 11 around the same axis as the rotation axis 19 of the crucible 11, Rotate it in the opposite direction to pull it up.

An inert gas such as argon (Ar), neon (Ne), and nitrogen (N) is introduced into the upper portion of the chamber to grow a smooth silicon monocrystalline ingot 10, I am using a lot of methods. Therefore, reference numeral 3 in FIG. 1 is a line showing a state in which argon (Ar) gas, which is an inert gas, is introduced into the upper portion of the growth apparatus and discharged to the lower portion of the growth apparatus for the growth of the silicon single crystal ingot 10 .

A radiating insulator or a heat shield 18 may be provided between the silicon single crystal ingot 10 and the crucible 11 so as to surround the ingot 10. This heat shield 18 has been developed in the course of designing various hot zones (H / Z) to reduce the deviation of the vertical temperature gradient in the crystal radial direction in accordance with the tendency that the wafer should have homogeneous characteristics in the plane And serves to control the cooling rate at the outer circumferential portion of the ingot 10 by cutting off heat radiated from the ingot 10.

The heat shield 18 is made of graphite coated with molybdenum (Mo), tungsten (W), carbon (C), or SiC, and can be formed into various shapes. Therefore, the shape of the heat shield 18 is not limited to the structure shown in FIG.

Further, when a silicon single crystal ingot is produced by the Czochralski (CZ) method, a magnetic field is applied to the silicon melt 12 contained in the crucible 11 during crystal growth of the ingot 10, A coil for applying a magnetic field to the silicon melt 12 is provided on the outer side of the chamber to change it. At this time, the coil arranges the lower coil 16 on the lower outer side of the chamber and the upper coil 17 on the upper side thereof.

In FIG. 1, reference numeral 2 denotes a magnetic field.

A silicon single crystal growth method according to the present invention is described below by applying a silicon single crystal growth apparatus having the above-described structure.

Referring to the drawings again, the silicon single crystal growth method according to the present invention is characterized in that the oxygen concentration level required by the asymmetric magnetic field control in the Czochralski (CZ) method for manufacturing a large diameter crystal of 200 mm or more It is a technique to control the oxygen concentration uniformly distributed in the crystal length direction without loss such as additional H / Z replacement and the like.

That is, it is possible to achieve the uniformity of the in-plane uniformity of the silicon wafer and the various oxygen concentration ranges required only by the special control of the magnetic field without changing the additional hot zone (H / Z) and parameters, The growth rate of the ingot can be improved and productivity can be expected to be improved.

Specifically, an asymmetric magnetic field is formed by flowing currents (asymmetrical) having different values to the upper and lower coils 17 and 16, respectively.

1, the ZGP (Zero Gauss Plane) is located above the surface of the silicon melt 12 based on the ZGP center position 'H', and the 'H' By adjusting the asymmetry ratio and the intensity of the upper and lower coils 17 and 16 provided in the upper and lower coils 17 and 16, respectively.

This adjusts the dissolution rate of SiOx dissolved from the crucible 11 due to the magnetic field component applied to the inner wall of the crucible 11, that is, the angle and intensity of the magnetic field applied to the inner wall of the crucible 11 according to the magnetic field, It is possible not only to realize a uniform oxygen concentration in the longitudinal direction of the Si crystal but also to achieve a required oxygen concentration level simply without changing the special hot zone (H / Z) and parameters.

1, the magnet installed outside the chamber is wrapped around the chamber with the upper and lower coils 17 and 16 wrapped around the chamber, The position of the ZGP (Zero Gauss Plane) line 1 is positioned above the surface of the silicon melt 12 as shown in FIG. 1 by adjusting the ratio and intensity of the magnetic field applied by the lower coils 17 and 16 It is possible to provide a high-quality single crystal growth method with high productivity by uniformly controlling the oxygen concentration in the second half of the crystal, especially through the asymmetric magnetic field control.

In order to provide the above-described method, in the silicon single crystal growth method according to the present invention, when a silicon single crystal is grown by the Czochralski (CZ) method, a magnetic field of a cusp type is used, The silicon single crystal is grown by controlling the oxygen concentration so that the ratio and the intensity of the magnetic field of the silicon single crystal are simultaneously changed.

 That is, in the method of growing a silicon single crystal according to the present invention, the intensity of the lower magnetic field measured when a cusp type magnetic field is applied is called G_lower, the intensity of the upper magnetic field is called G_upper, and the ratio of the upper and lower magnetic fields is adjusted The following equation (1) is satisfied.

1.00? Exp (G_lower / G_upper)? 135.00

On the other hand, data as shown in the table and graph of FIG. 4, which will be described later, was obtained as an example of the test. The above equation (1) by this test can be described as follows.

2.718? Exp (G_lower / G_upper)? 134.29

The above equation (1) represents the range when the upper and lower ratios are applied, and as the numerical value increases, the asymmetry increases. Therefore, assuming that the positions of the coils 16 and 17 are not physically moved but are fixed at certain positions, the ZGP center 'H' in the case of varying the ratios as shown in FIG. 1, 12) upwards, resulting in a low level of oxygen concentration.

At this time, when the surface position of the ZGP and the silicon melt 12 coincides with the upper portion of the heater 14 based on the heater top at the time of application of the magnetic field by the upper and lower coils 17 and 16, , The relationship between the position of the ZGP and the surface of the silicon melt (12) is given by the following equation (2).

0 ≤ ZGP_center - Silicon melt surface ≤ 500

Equation (2) is an equation indicating that the position of the ZGP should be located at least above the surface of the silicon melt 12. [ Therefore, it always has a (+) value. In this embodiment, the Zero Gauss Plane (ZGP) is located above the surface of the silicon melt 12 based on the ZGP center position 'H', but it may not be limited to this.

The ZGP of the magnetic field applied under the conditions of equations (1) and (2) above is measured with respect to the radial direction inside the crystal growth furnace, and the following relation is obtained as shown in the following equation (3).

Y = C 1 - C 2 X - C 3 X 2

Here, Y is the ZGP position, X is the radial position inside the crucible, and C 1, C 2, and C 3 are coefficients when the magnetic field ratio is applied.

The equation (3) is a relational expression obtained by deriving a regression equation using a statistical tool based on experimental data. The equation is expressed by a quadratic equation as shown in equation (3), and a parabolic form (asymmetric) As shown in Fig.

Further, the coefficient C value in Equation (3) obtained by applying equations (1) and (2) can be made in the range of the following equations (4) and (5) by changing the physical magnet movement or the upper and lower magnetic field ratios.

C₁≤500

Equation (4) represents the intercept value of Equation (3) and represents the position 'H' of the ZGP center and is located at a maximum of 500 mm or less in relation to Equation (2).

1? Exp (C? 3 / C?)? 25

The above equation (5) shows the relationship between the coefficients C 2 and C 3 for the equation (3), and also shows that as the value increases, the asymmetry increases.

In other words, based on Equations (4) and (5), Equation (3) shows that C 1 is a slice value, and ZGP center 'H' is located within a range of 500 or less. In the crystal growth furnace, Good results were obtained when the ratio of ZGP positions was in the range of 1 to 25. [

As a result, all of the above equations means that when the asymmetry of the magnetic field follows the above equation and the position of the ZGP is located above the surface of the silicon melt 12 and operated within the specified range, the oxygen concentration is controlled to a desired level .

FIG. 2 shows the level of oxygen concentration along the length direction of the single crystal as a result of the growth of the single crystal under the conditions satisfying the relations of the above-mentioned formulas 1 to 5.

As shown in the graph of FIG. 2, the graph (dotted line) before the improvement shows that, due to the Oi (Interstitial Oxygen) pumping phenomenon in the longitudinal direction, especially in the rear part of the body during Si ingot growth, (About 10.50 ppma (parts per million atoms)) to the approximate upper / lower limit value (thin solid line) for the oxygen concentration as data (data) which causes deterioration of the productivity due to a decrease in the homogeneity of the oxygen concentration with respect to the oxygen concentration, The uniformity of the oxygen concentration in the longitudinal direction of the Si ingot is lowered in the conventional method.

On the contrary, after the improvement of the application result of the present invention, it is shown that uniform interstitial oxygen concentration was obtained at 70% or more of the entire length of the ingot from the beginning to the end of the body. It can be seen that the Oi pumping phenomenon before the improvement by the adjustment of the magnetic field ratio and the intensity is applied according to the intention of the present invention.

And FIG. 3 shows experimental data showing that Test 1 and Test 2 can achieve the required oxygen concentration without changing the additional hot zone (H / Z) or parameter by applying the same magnetic field ratio but changing only the magnetic field strength As shown in the graph. In this graph, Test 1 is the same ratio for Test 2, and the relative magnetic field intensity is about 1 magnetic field of Test 1.

As shown in FIG. 2, it can be seen that the level of oxygen concentration along the length direction of the single crystal is uniform and the Oi pumping phenomenon in the latter half is effectively suppressed.

Referring to the table and the graph shown in FIG. 4, first, the table of FIG. 4 shows the relationship between the asymmetric ratio of the magnetic field and the amount of oxygen concentration when the upper and lower currents of the magnetic field are asymmetrically applied in actual silicon single crystal growth according to Equation As shown, a graph thereon is shown together in Fig. As described above, as the ratio of the asymmetric magnetic field increases, the component of the magnetic field component applied to the inner wall of the quartz crucible 11 changes, and consequently, the oxygen concentration level is lowered.

Also, referring to the table and the graph of FIG. 5, FIG. 5 shows an example in which the oxygen concentration level can be controlled according to the magnetic field intensity when the same ratio of asymmetric magnetic field is formed. It can be confirmed that a higher level of oxygen concentration is realized compared to the case of forming a relatively strong magnetic field and that the oxygen concentration level can be controlled by appropriately adjusting the magnetic field intensity even if the magnetic field ratio is different.

It is confirmed that the oxygen concentration level can be controlled only by the intensity of the magnetic field to be operated when any condition is satisfied regardless of the numerical values of the above Equations 1 to 5 when applied in actual field.

Further, the silicon single crystal growth method according to the present invention can adjust the ratio and intensity of the magnetic field according to the oxygen concentration requirement level of the customer as well as the low oxygen concentration of the oxygen concentration of 10.5 ppma or less, , It is possible to simply adjust the level of oxygen concentration, that is, the oxygen concentration between the ingots in the lattice to one of 6 ppma to 14 ppm due to the adjustment of Equations 1 to 5 as shown in Fig.

Therefore, by applying the silicon single crystal growth method according to the present invention, it is possible to grow a single crystal having a uniform quality distribution in the lengthwise direction of the single crystal without loss due to an additional change in hot zone (H / Z) In particular, productivity improvement can be expected by maximizing the prime length due to the suppression effect of the oxygen concentration pumping in the latter half.

As described above, the silicon single crystal growth method according to the present invention has the following effects.

In the Czochralski method for manufacturing large diameter crystals of not less than 200 mm in diameter as well as small and medium calibers, various levels of oxygen concentration required through asymmetric magnetic field control are uniformly distributed in the crystal length direction without loss such as additional hot zone (H / Z) Can be controlled.

In order to control the oxygen concentration of the single crystal, the position of the ZGP is located above the surface of the silicon melt and the productivity can be improved by controlling the oxygen concentration uniformly in the latter half of the crystal through the asymmetric magnetic field control. .

In addition, ZGP can be positioned on the surface of the melt and the asymmetric magnetic field control can control the uniform concentration of oxygen in the entire single crystal longitudinal direction regardless of the length of the single crystal depending on the aperture and charge size.

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 and modifications may be made without departing from the scope of the invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (14)

A method of growing a silicon single crystal ingot by using a magnetic field applied by a coil disposed on the upper and lower sides of a silicon single crystal growing apparatus for pulling up a single crystal seed from a silicon melt by a Czochralski (CZ) method As a result, The magnetic field applied by the coil is a cusp type asymmetric magnetic field, Wherein the ratio of the asymmetric magnetic field or the intensity of the asymmetric magnetic field is controlled to control the oxygen concentration in the longitudinal direction of the single crystal. delete A method of growing a silicon monocrystal ingot using a cusp magnetic field generated by a coil disposed at the upper and lower outer sides of a silicon single crystal growing apparatus for pulling up a single crystal from a silicon melt by a Czochralski (cz) method As a result, The intensity of the lower magnetic field measured in applying the cusp magnetic field is called G_lower and the intensity of the upper magnetic field is called G_upper. In adjusting the ratio of the magnetic field in the upper and lower portions, Wherein the silicon single crystal ingot is grown on the silicon substrate. [ Equation 1 ] 1.00? Exp (G_lower / G_upper)? 135.00 A method of growing a silicon monocrystal ingot using a cusp magnetic field generated by a coil disposed at the upper and lower outer sides of a silicon single crystal growing apparatus for pulling up a single crystal from a silicon melt by a Czochralski (cz) method As a result, When the ZGP (Zero Gauss Plane) and the position of the surface of the silicon melt coincide with the upper portion of the heater of the silicon single crystal growing apparatus when the magnetic field is applied by the upper and lower coils, Wherein the relationship between the position of the ZGP and the surface of the silicon melt assumes a negative (-) position, and satisfies the following formula (2). & Quot; (2 ) & quot ; 0 ≤ ZGP_center - Silicon melt surface ≤ 500 The method according to claim 3 or 4, Wherein ZGP of a magnetic field applied under the conditions of Equation (1) or (2) is defined by the following equation (3) with respect to the radial direction of the silicon single crystal growth apparatus. & Quot; (3 ) & quot ; Y = C 1 - C 2 X - C 3 X 2 Where Y is the ZGP position, X is a radial position inside the crucible, C ₁, C ₂, and C ₃ are coefficients when magnetic field ratio is applied. 6. The method of claim 5, Wherein the value of the coefficient C 1 in the equation (3) is in the range of the following formula (4) due to the movement of the coil or the change of the ratio of the upper and lower magnetic fields. & Quot; (4 ) & quot ; C₁≤500 6. The method of claim 5, Wherein the values of the coefficients C 2 and C 3 in Equation (3) are changed in accordance with the movement of the coil or the ratio of the upper and lower magnetic fields. & Quot; (5 ) & quot ; 1? Exp (C? 3 / C?)? 25 The method according to claim 1, Wherein the asymmetric magnetic field comprises an upper magnetic field and a lower magnetic field generated by the upper and lower coil members disposed outside the silicon single crystal ingot growing apparatus and the intensity of the upper magnetic field and the lower magnetic field is at least one of the upper and lower coil members Wherein the current is controlled by an applied current. 9. The method of claim 8,  And a ZGP (Zero Gauss Plane) is positioned above the silicon melt surface by a change in the ratio of the upper magnetic field and the lower magnetic field. 9. The method of claim 8, Wherein the intensity of the upper magnetic field and the intensity of the lower magnetic field are different from each other and the intensity of the lower magnetic field is higher than the upper magnetic field. delete In a silicon monocrystal ingot grown by the Chokoraski method with a cusp magnetic field asymmetrically applied to the upper and lower portions of the silicon single crystal ingot growing apparatus by the upper and lower coil members disposed on the outer side of the silicon single crystal ingot growing apparatus, Wherein the crystal growth direction is constant in the radial direction of the ingot and the interstitial oxygen concentration is uniform at 70% or more of the total length of the ingot. 13. The method of claim 12, (G_lower / G_upper) < / = 135.00 (G_lower / G_upper) when the ratio of the magnetic field of the lower and upper magnetic domains is G_lower and the intensity of the upper magnetic field is G_upper, Wherein the interstitial oxygen concentration is adjusted to one of 6 ppma to 14 ppm. 13. The method of claim 12, The silicon single crystal ingot having a diameter of 200 mm or more.

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