Single crystal silicon rod growth method and device

Abstract

The present invention provides a method and a device for growing a single crystal silicon rod, belonging to the technical field of semiconductor manufacturing. The single crystal silicon rod growing device includes: a crucible assembly, including a graphite crucible and a quartz crucible disposed within the graphite crucible, the quartz crucible being used for containing a silicon melt; a superconductor assembly surrounding the crucible assembly, the superconductor assembly including a plurality of superconductors arranged in a vertical direction, the plurality of superconductors being independent of each other; and a control unit connected to the superconductor assembly for respectively adjusting the magnetic field intensities of the plurality of superconductors during the growth process of the single crystal silicon rod. The technical solution of the present invention can improve the product yield of the single crystal silicon rod.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular, to a method and apparatus for growing a single crystal silicon rod. Background Art

[0002] As a semiconductor material, single crystal silicon is generally used to manufacture integrated circuits and other electronic components. In the process of preparing single crystal silicon, a seed crystal with a smaller diameter is immersed in a silicon melt, and a thin crystal with a smaller diameter is grown by seed crystal introduction to discharge dislocations so as to achieve the purpose of growing a zero-dislocation crystal. Then, through the shoulder release process, the crystal grows from the thin crystal to the target diameter, and then the crystal with the required size is obtained through isodiametric growth. Finally, through the finishing process, the crystal bar is separated from the liquid surface to obtain a complete crystal.

[0003] During the growth of a single crystal silicon rod, a magnetic field can be applied to a quartz crucible containing a silicon melt to change the oxygen concentration of the silicon melt, reduce the defects of the single crystal silicon rod, and improve the quality of the single crystal silicon rod. However, in the related art, the applied magnetic field intensity is single. When the overall magnetic field intensity changes, it is easy to cause a sudden and drastic change in the convection in the silicon melt, a large temperature change, and not only a large axial change but also

[0004] a large radial change difference in the oxygen content entering the single crystal silicon rod from the inside of the silicon melt, affecting the uniformity of the oxygen content in the single crystal silicon rod; in addition, the drastic temperature change further causes the pulling speed to be unstable, an increase in the defects inside the crystal, and a reduction in the yield of the single crystal silicon rod. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method and apparatus for growing a single crystal silicon rod, which can improve the product yield of the single crystal silicon rod.

[0006] To achieve the above object, the technical solution adopted in the embodiment of the present invention is:

[0007] A single crystal silicon rod growth apparatus, comprising:

[0008] A crucible assembly, including a graphite crucible and a quartz crucible disposed inside the graphite crucible, the quartz crucible being used for containing a silicon melt;

[0009] A superconductor assembly surrounding the crucible assembly, the superconductor assembly including a plurality of superconductors disposed along the vertical direction, the plurality of superconductors being independent of each other;

[0010] A control unit, connected to the superconductor assembly, for respectively adjusting the magnetic field intensity of the plurality of superconductors during the growth process of the single crystal silicon rod.

[0011] In some embodiments, it further includes:

[0012] A lifting mechanism connected to the crucible assembly for controlling the vertical movement of the crucible assembly.

[0013] In some embodiments, the superconductor assembly includes, from top to bottom in the vertical direction:

[0014] A first superconductor, a second superconductor, and a third superconductor.

[0015] In some embodiments, the lifting mechanism is specifically configured to move the crucible assembly during the growth of a single crystal silicon rod such that the solid-liquid interface in the quartz crucible is located within the magnetic field region generated by the first superconductor.

[0016] In some embodiments, the control unit is configured to control the initial magnetic fields of the plurality of superconductors to gradually increase in intensity from top to bottom in the vertical direction.

[0017] In some embodiments, it further includes:

[0018] A diameter monitoring component for monitoring the diameter of the grown single crystal silicon rod to obtain a diameter monitoring result;

[0019] The control unit, connected to the diameter detection component, is further configured to receive the diameter monitoring result of the diameter monitoring component during the growth of the single crystal silicon rod and adjust the magnetic field intensities of the plurality of superconductors according to the diameter monitoring result.

[0020] In some embodiments, the control unit is specifically configured to adjust the magnetic field intensity of the third superconductor according to the difference between the target diameter and the diameter monitoring result when the crucible assembly moves into the magnetic field range of the third superconductor; adjust the magnetic field intensity of the second superconductor according to the difference between the target diameter and the diameter monitoring result when the crucible assembly moves into the magnetic field range of the second superconductor; and adjust the magnetic field intensity of the first superconductor according to the difference between the target diameter and the diameter monitoring result when the crucible assembly moves into the magnetic field range of the first superconductor.

[0021] In some embodiments, the control unit is further configured to obtain defect data of the single crystal silicon rod after the growth of the single crystal silicon rod is completed and adjust the initial magnetic field intensities of the plurality of superconductors according to the defect data.

[0022] An embodiment of the present invention further provides a method for growing a single crystal silicon rod, which is applied to the single crystal silicon rod growth device as described above and includes:

[0023] Using the control unit to respectively adjust the magnetic field intensities of the plurality of superconductors during the growth of the single crystal silicon rod.

[0024] In some embodiments, the method further includes:

[0025] During the growth of the single crystal silicon rod, use the lifting mechanism to move the crucible assembly so that the solid-liquid interface in the quartz crucible is located within the magnetic field region generated by the first superconductor.

[0026] The beneficial effects of the present invention are as follows:

[0027] In this embodiment, the superconductor assembly includes a plurality of superconductors arranged vertically. The plurality of superconductors are independent of each other. In this way, during the growth of the single crystal silicon rod, the magnetic field intensity of each superconductor can be adjusted separately. It can achieve the control of the stratified convection of the silicon melt inside the quartz crucible, avoid the sudden and drastic change of the convection in the silicon melt, ensure the uniformity of the radial and axial oxygen content inside the crystal during single crystal growth; in addition, it can also ensure the stability of the pulling speed during crystal growth, improve the stability and reliability of the product quality of the single crystal silicon rod, and improve the product yield of the single crystal silicon rod. Description of the Drawings

[0028] Figure 1 It shows a schematic structural diagram of the single crystal silicon rod growth device according to an embodiment of the present invention;

[0029] Figure 2 It shows a schematic flow diagram of the single crystal silicon rod growth method according to an embodiment of the present invention.

[0030] Reference Signs

[0031] 1 First superconductor

[0032] 2 Second superconductor

[0033] 3 Third superconductor

[0034] 4 Quartz crucible

[0035] 5 Graphite crucible

[0036] 6 Silicon melt

[0037] 7 Magnetic field lines

[0038] 8 Single crystal silicon rod Detailed Embodiments

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0041] The present invention provides a method and device for growing a single crystal silicon rod, which can improve the product yield of the single crystal silicon rod.

[0042] An embodiment of the present invention provides a device for growing a single crystal silicon rod, as Figure 1 shown, including:

[0043] A crucible assembly, including a graphite crucible 5 and a quartz crucible 4 disposed inside the graphite crucible 5, and the quartz crucible 4 is used to hold a silicon melt 6;

[0044] A superconductor assembly surrounding the crucible assembly, the superconductor assembly includes a plurality of superconductors disposed along the vertical direction, the plurality of superconductors are independent of each other, and when the superconductors are turned on, magnetic field lines 7 penetrating the crucible assembly are generated, and the convection of the silicon melt 6 can be controlled through the magnetic field lines 7;

[0045] A control unit, connected to the superconductor assembly, for adjusting the magnetic field intensity of the plurality of superconductors respectively during the growth process of the single crystal silicon rod 8.

[0046] In this embodiment, the superconductor assembly includes a plurality of superconductors disposed along the vertical direction, and the plurality of superconductors are independent of each other. In this way, during the growth process of the single crystal silicon rod, the magnetic field intensity of each superconductor can be adjusted respectively. It can realize the layered convection control of the silicon melt inside the quartz crucible, avoid the sudden drastic change of the convection inside the silicon melt, and ensure the uniformity of the radial and axial oxygen content inside the crystal during single crystal growth; in addition, it can also ensure the stability of the pulling speed during crystal growth, improve the stability and reliability of the product quality of the single crystal silicon rod, and improve the product yield of the single crystal silicon rod.

[0047] In some embodiments, as Figure 1 shown, the superconductor assembly includes the following superconductors arranged in sequence from top to bottom along the vertical direction:

[0048] A first superconductor 1, a second superconductor 2 and a third superconductor 3. Of course, this embodiment is not limited to setting three superconductors, and more superconductors can also be set, such as four superconductors, five superconductors, etc. Each superconductor is in a ring shape, surrounding the crucible assembly, and the axes of the plurality of superconductors coincide.

[0049] In some embodiments, the single-crystal silicon rod growth device further comprises:

[0050] A lifting mechanism connected to the crucible assembly for controlling the crucible assembly to move in the vertical direction. During the growth of the single-crystal silicon rod, the lifting mechanism can move the crucible assembly so that the solid-liquid interface in the quartz crucible is located within the magnetic field region generated by the first superconductor 1. In this way, even if the magnetic field intensities of the second superconductor 2 and the third superconductor 3 change, the stability of the solid-liquid interface can be ensured, the oxygen precipitation fluctuation caused by the change in the magnetic field intensity can be weakened, the uniformity of the radial oxygen content and the stability of the pulling speed during crystal growth can be achieved. On the one hand, it ensures the uninterrupted growth of the single-crystal silicon rod, and on the other hand, it ensures the product quality of the single-crystal silicon rod.

[0051] In some embodiments, the control unit is used to control the initial magnetic fields of the multiple superconductors to gradually increase in intensity from top to bottom in the vertical direction.

[0052] As Figure 1 shown, when the superconductor assembly includes the first superconductor 1, the second superconductor 2, and the third superconductor 3, the magnetic field intensities generated by the first superconductor 1, the second superconductor 2, and the third superconductor 3 gradually increase from top to bottom, which can realize the convective stratification control of the silicon melt, and further realize the uniform change of the axial oxygen content inside the crystal.

[0053] In some embodiments, the single-crystal silicon rod growth device further comprises:

[0054] A diameter monitoring component for monitoring the diameter of the grown single-crystal silicon rod to obtain a diameter monitoring result;

[0055] The control unit, connected to the diameter detection component, is further configured to receive the diameter monitoring result of the diameter monitoring component during the growth of the single-crystal silicon rod and adjust the magnetic field intensities of the multiple superconductors according to the diameter monitoring result.

[0056] In this way, the magnetic field intensities of the multiple superconductors can be adjusted according to the diameter detection result, so that the actual diameter of the single-crystal silicon rod reaches the target diameter.

[0057] When the single-crystal silicon rod growth device is working, as Figure 1 shown, the graphite crucible 5 wraps the quartz crucible 4, and the quartz crucible 4 contains a silicon melt 6. When the single-crystal silicon rod 8 is growing, the first superconductor 1, the second superconductor 2, and the third superconductor 3 are turned on simultaneously, and the magnetic field intensity is increased step by step, thereby suppressing the thermal convection inside the silicon melt and the oxygen migration caused by the convection, and realizing the uniform change of the axial oxygen content inside the crystal.

[0058] In addition, during the growth of the single-crystal silicon rod 8, driven by the lifting mechanism, the crucible assembly moves upward in the vertical direction, ensuring that the solid-liquid interface in the quartz crucible is always within the magnetic field region generated by the first superconductor 1, which can guarantee the stability of the solid-liquid interface, reduce the oxygen precipitation fluctuation caused by the change in magnetic field intensity, achieve the uniformity of the radial oxygen content and the stability of the pulling speed during crystal growth. On the one hand, it ensures the continuous growth of the single-crystal silicon rod, and on the other hand, it guarantees the product quality of the single-crystal silicon rod.

[0059] During the upward movement of the crucible assembly, when the crucible assembly moves into the magnetic field range of the third superconductor 3, the control unit can adjust the magnetic field intensity of the third superconductor 3 according to the difference between the target diameter and the diameter monitoring result; when the crucible assembly moves into the magnetic field range of the second superconductor 2, the control unit can adjust the magnetic field intensity of the second superconductor 2 according to the difference between the target diameter and the diameter monitoring result; when the crucible assembly moves into the magnetic field range of the first superconductor 1, the control unit can adjust the magnetic field intensity of the first superconductor 1 according to the difference between the target diameter and the diameter monitoring result.

[0060] Specifically, when the diameter monitoring result is greater than the target diameter, the magnetic field intensity of the corresponding superconductor can be lowered; when the diameter monitoring result is less than the target diameter, the magnetic field intensity of the corresponding superconductor can be increased to achieve the control of the diameter of the single-crystal silicon rod.

[0061] In this embodiment, the superconductor can suppress the thermal convection inside the silicon melt through the magnetic field. The greater the magnetic field intensity, the stronger the suppression of the convection inside the silicon melt, and the smaller the magnetic field intensity, the lower the suppression of the convection inside the silicon melt. In addition, the temperature of the silicon melt is the key factor determining the diameter of the single-crystal silicon rod. The lower the temperature, the gradually stronger the growth in the radial direction of the single-crystal silicon rod and the larger the diameter; the higher the temperature, the gradually weaker the growth in the radial direction of the single-crystal silicon rod and the smaller the diameter. Therefore, by controlling the thermal convection inside the silicon melt through the magnetic field, the diameter of the single-crystal silicon rod can be controlled. When the diameter of the single-crystal silicon rod is too large, the magnetic field intensity of the superconductor is reduced, the suppression of the convection inside the silicon melt is reduced, and the temperature of the silicon melt is increased, thereby making the diameter of the single-crystal silicon rod smaller; when the diameter of the single-crystal silicon rod is too small, the magnetic field intensity of the superconductor is increased, the suppression of the convection inside the silicon melt is increased, and the temperature of the silicon melt is reduced, thereby making the diameter of the single-crystal silicon rod larger.

[0062] In some embodiments, the control unit is further configured to, after the growth of the single-crystal silicon rod is completed, obtain the defect data of the single-crystal silicon rod and adjust the initial magnetic field intensity of the multiple superconductors according to the defect data.

[0063] After the growth of the single-crystal silicon rod is completed, the single-crystal silicon rod will be evaluated. The single-crystal silicon rod is sliced every 300 - 450 mm, and the slices are inspected for defects. If the pulling speed (P / S) is too high, it will cause the appearance of defects such as V-rich and P-band, while if the P / S is too low, defects such as I-rich and B-band will appear. A superconductor can suppress the thermal convection inside the silicon melt through a magnetic field. The greater the magnetic field strength, the stronger the suppression of convection inside the silicon melt, and the smaller the magnetic field strength, the lower the suppression of convection inside the silicon melt. In addition, the suppression of convection inside the silicon melt affects the temperature of the silicon melt, and the temperature of the silicon melt affects P / S. Therefore, the control of P / S can be indirectly achieved by controlling the thermal convection of the silicon melt through a magnetic field. When P / S is too high, the magnetic field strength of the superconductor is reduced, the suppression of convection inside the silicon melt is reduced, the temperature of the silicon melt is increased, and thus P / S becomes smaller. When P / S is too low, the magnetic field strength of the superconductor is increased, the suppression of convection inside the silicon melt is increased, the temperature of the silicon melt is reduced, and thus P / S becomes larger.

[0064] An embodiment of the present invention also provides a method for growing a single-crystal silicon rod, which is applied to the single-crystal silicon rod growth device as described above, and includes:

[0065] During the growth of the single-crystal silicon rod, the control unit is used to adjust the magnetic field strengths of the multiple superconductors respectively.

[0066] In this embodiment, the superconductor assembly includes multiple superconductors arranged vertically, and the multiple superconductors are independent of each other. In this way, during the growth of the single-crystal silicon rod, the magnetic field strength of each superconductor can be adjusted respectively. It can realize the layered convection control of the silicon melt inside the quartz crucible, avoid the sudden violent change of convection inside the silicon melt, and ensure the uniformity of the radial and axial oxygen contents inside the crystal during single-crystal growth. In addition, it can also ensure the stability of the pulling speed during crystal growth, improve the stability and reliability of the product quality of the single-crystal silicon rod, and improve the product yield of the single-crystal silicon rod.

[0067] In some embodiments, the method further includes:

[0068] During the growth of the single-crystal silicon rod, the lifting mechanism is used to move the crucible assembly so that the solid-liquid interface inside the quartz crucible is located within the magnetic field region generated by the first superconductor.

[0069] During the growth of the single-crystal silicon rod, as Figure 1 shown, the graphite crucible 5 wraps the quartz crucible 4, and the quartz crucible 4 contains a silicon melt 6 inside; as Figure 2 shown, during the growth of the single-crystal silicon rod 8, the first superconductor 1, the second superconductor 2, and the third superconductor 3 are turned on simultaneously, and the magnetic field strength is gradually increased, so as to suppress the thermal convection inside the silicon melt and the oxygen migration caused by the convection, and realize the uniform change of the axial oxygen content inside the crystal.

[0070] In addition, when the single-crystal silicon rod 8 is growing, driven by the lifting mechanism, the crucible assembly moves upward in the vertical direction, so that the solid-liquid interface in the quartz crucible is always located within the magnetic field region generated by the first superconductor 1, which can ensure the stability of the solid-liquid interface, weaken the oxygen precipitation fluctuation caused by the change of the magnetic field intensity, realize the uniformity of the radial oxygen content and the stability of the pulling speed during crystal growth. On the one hand, it ensures that the growth of the single-crystal silicon rod is not interrupted, and on the other hand, it ensures the product quality of the single-crystal silicon rod.

[0071] During the upward movement of the crucible assembly, when the crucible assembly moves into the magnetic field range of the third superconductor 3, the control unit can adjust the magnetic field intensity of the third superconductor 3 according to the difference between the target diameter and the diameter monitoring result; when the crucible assembly moves into the magnetic field range of the second superconductor 2, the control unit can adjust the magnetic field intensity of the second superconductor 2 according to the difference between the target diameter and the diameter monitoring result; when the crucible assembly moves into the magnetic field range of the first superconductor 1, the control unit can adjust the magnetic field intensity of the first superconductor 1 according to the difference between the target diameter and the diameter monitoring result.

[0072] Specifically, when the diameter monitoring result is greater than the target diameter, the magnetic field intensity of the corresponding superconductor can be lowered; when the diameter monitoring result is less than the target diameter, the magnetic field intensity of the corresponding superconductor can be raised to realize the control of the diameter of the single-crystal silicon rod.

[0073] In some embodiments, as Figure 2 shown, after the growth of the single-crystal silicon rod is completed, the defect data of the single-crystal silicon rod can also be obtained, and the initial magnetic field intensities of the multiple superconductors can be adjusted according to the defect data.

[0074] It should be noted that the various embodiments in this specification are described in a progressive manner. The same or similar parts among the various embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments. In particular, for the method embodiment, since it is basically similar to the product embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the product embodiment.

[0075] In the description of the above embodiments, the specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0076] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present disclosure, and all of them should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A single-crystalline silicon rod growth device, characterized in that, Comprising: A crucible assembly, including a graphite crucible and a quartz crucible disposed within the graphite crucible, the quartz crucible being used to hold a silicon melt; A superconductor assembly surrounding the crucible assembly, the superconductor assembly including a plurality of superconductors arranged vertically, the plurality of superconductors being independent of each other; A control unit, connected to the superconductor assembly, for adjusting the magnetic field intensities of the plurality of superconductors respectively during the growth process of a single crystal silicon rod; A lifting mechanism connected to the crucible assembly, for controlling the crucible assembly to move vertically; The superconductor assembly includes, from top to bottom in the vertical direction: A first superconductor, a second superconductor, and a third superconductor; The lifting mechanism is specifically used to move the crucible assembly during the growth process of a single crystal silicon rod, so that the solid-liquid interface in the quartz crucible is located within the magnetic field region generated by the first superconductor.

2. The single-crystalline silicon rod growth device according to claim 1, characterized in that, The control unit is used to control the initial magnetic fields of the plurality of superconductors to gradually increase in intensity from top to bottom in the vertical direction.

3. The single-crystalline silicon rod growth device according to claim 1, characterized in that, It further comprises: A diameter monitoring assembly, for monitoring the diameter of the grown single crystal silicon rod to obtain a diameter monitoring result; The control unit, connected to the diameter detection assembly, is further used to receive the diameter monitoring result of the diameter monitoring assembly during the growth process of a single crystal silicon rod, and adjust the magnetic field intensities of the plurality of superconductors according to the diameter monitoring result.

4. The single-crystalline silicon rod growth device according to claim 3, characterized in that, The control unit is specifically used to adjust the magnetic field intensity of the third superconductor according to the difference between the target diameter and the diameter monitoring result when the crucible assembly moves into the magnetic field range of the third superconductor; adjust the magnetic field intensity of the second superconductor according to the difference between the target diameter and the diameter monitoring result when the crucible assembly moves into the magnetic field range of the second superconductor; adjust the magnetic field intensity of the first superconductor according to the difference between the target diameter and the diameter monitoring result when the crucible assembly moves into the magnetic field range of the first superconductor.

5. The single-crystalline silicon rod growth device according to claim 2, characterized in that, The control unit is further used to obtain defect data of the single crystal silicon rod after the growth of the single crystal silicon rod is completed, and adjust the initial magnetic field intensities of the plurality of superconductors according to the defect data.

6. A single-crystalline silicon rod growth method, characterized in that, Applied to the single crystal silicon rod growth device according to any one of claims 1-5, including: Using the control unit to adjust the magnetic field intensities of the plurality of superconductors respectively during the growth process of a single crystal silicon rod.

7. The single-crystalline silicon rod growth method according to claim 6, characterized in that, The method further comprises: Using the lifting mechanism to move the crucible assembly during the growth process of a single crystal silicon rod, so that the solid-liquid interface in the quartz crucible is located within the magnetic field region generated by the first superconductor.

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