阅读说明：本技术 一种磁控拉单晶超导磁体及磁屏蔽方法 (Magnetic control single crystal pulling superconducting magnet and magnetic shielding method ) 是由 刘伟 李超 马鹏 张弛 李勇 葛正福 兰贤辉 冯勇 刘向宏 张平祥 于 2021-09-22 设计创作，主要内容包括：本发明公开了一种磁控拉单晶超导磁体,包括屏蔽结构和超导线圈。屏蔽结构包括磁屏蔽铁轭上板、磁屏蔽铁轭下板和磁屏蔽铁轭筒体,磁屏蔽铁轭上板和磁屏蔽铁轭下板分别连接在磁屏蔽铁轭筒体的两端,磁屏蔽铁轭筒体为多层结构。超导线圈设置在磁屏蔽结构内部。本发明采用多层优化过的磁屏蔽结构,在节约电工纯铁的基础上,进一步降低磁体的漏磁,从而满足磁控拉单晶用超导磁体周围电气设备的安全、稳定运行。同时单层磁屏蔽结构的厚度也较小,可以降低因单层较厚电工纯铁磁屏蔽结构造成的磁屏蔽与超导线圈之间的电磁作用力过大,诱发的磁体运行稳定性问题的风险,提高磁控拉单晶用超导磁体的稳定性,保证生产效率及稳定性。(The invention discloses a magnetic control single crystal pulling superconducting magnet, which comprises a shielding structure and a superconducting coil. The shielding structure comprises a magnetic shielding iron yoke upper plate, a magnetic shielding iron yoke lower plate and a magnetic shielding iron yoke barrel, the magnetic shielding iron yoke upper plate and the magnetic shielding iron yoke lower plate are respectively connected to two ends of the magnetic shielding iron yoke barrel, and the magnetic shielding iron yoke barrel is of a multilayer structure. The superconducting coil is disposed inside the magnetic shield structure. The invention adopts a multilayer optimized magnetic shielding structure, further reduces the magnetic leakage of the magnet on the basis of saving electrician pure iron, thereby meeting the requirement of safe and stable operation of electrical equipment around the superconducting magnet for magnetically controlling and pulling single crystals. Meanwhile, the thickness of the single-layer magnetic shielding structure is smaller, the risk of the problem of the induced running stability of the magnet due to overlarge electromagnetic acting force between the magnetic shielding and the superconducting coil caused by the single-layer thicker electrician pure iron magnetic shielding structure can be reduced, the stability of the superconducting magnet for magnetic control crystal pulling is improved, and the production efficiency and the stability are ensured.)

1. A magnetic control single crystal pulling superconducting magnet is characterized by comprising a shielding structure and a superconducting coil (410);

the shielding structure includes: the magnetic shielding iron yoke comprises a magnetic shielding iron yoke upper plate (100), a magnetic shielding iron yoke lower plate (110) and a magnetic shielding iron yoke barrel (120), wherein the magnetic shielding iron yoke upper plate (100) and the magnetic shielding iron yoke lower plate (110) are respectively connected to two ends of the magnetic shielding iron yoke barrel (120), and the magnetic shielding iron yoke barrel (120) is of a multilayer structure;

the superconducting coil (410) is disposed inside the magnetic shielding structure.

2. The magnetron pulled single crystal superconducting magnet as claimed in claim 1, wherein the magnetic shielding yoke upper plate (100) and the magnetic shielding yoke lower plate (110) are parallel to each other, two ends of the magnetic shielding yoke cylinder (120) are vertically connected to the magnetic shielding yoke upper plate (100) and the magnetic shielding yoke lower plate (110), respectively, and the magnetic shielding yoke cylinder (120) is located at an outer edge position of the magnetic shielding yoke upper plate (100) and the magnetic shielding yoke lower plate (110).

3. A magnetically controlled single crystal pulling superconducting magnet according to claim 1, wherein the magnetic shielding yoke upper plate (100), the magnetic shielding yoke lower plate (110) and the magnetic shielding yoke barrel (120) are all made of electrical pure iron.

4. A magnetically controlled pulled single crystal superconducting magnet according to claim 1, further comprising a dewar (200), the dewar (200) being a hollow closed structure, the dewar (200) being disposed inside the magnetic shielding structure, the superconducting coil (410) being disposed inside the dewar (200).

5. A magnetically controlled pulled single crystal superconducting magnet according to claim 4, wherein the dewar (200) comprises an outer dewar and an inner dewar (130);

the outer Dewar is arranged on one side, close to the magnetic shielding iron yoke barrel (120), of the interior of the shielding structure, and the inner Dewar (130) is arranged on the position close to the axis of the shielding structure.

6. A magnetically controlled pulled single crystal superconducting magnet according to claim 5, wherein the inner Dewar (130) is made of a non-magnetic material.

7. A magnetically controlled single crystal pulling superconducting magnet according to claim 4, further comprising a cold shield (300), wherein the cold shield (300) is a hollow structure, the cold shield (300) is disposed inside the Dewar (200), and the superconducting coil (410) is disposed inside the cold shield (300).

8. The superconducting magnet of claim 7, further comprising a refrigerator (500), wherein the refrigerator (500) is disposed outside the shielding structure, a primary cold head (510) is connected to a refrigeration output end of the refrigerator (500), and the primary cold head (510) is connected to the cold shield (300).

9. A magnetically controlled single crystal pulling superconducting magnet according to claim 1, wherein the superconducting coil (410) is wound on a coil former (400).

10. The magnetic shielding method applied to the magnetic control pulling single crystal superconducting magnet of any one of claims 1 to 9, is characterized by comprising the following steps:

determining the layer number of the magnetic shielding structure;

assembling the magnetic shielding structure;

a superconducting coil (410) is disposed inside the magnetic shield structure.

Technical Field

The invention relates to the technical field of semiconductor production equipment, in particular to a magnetic control single crystal pulling superconducting magnet and a magnetic shielding method.

Background

The high-purity monocrystalline silicon is widely applied to industries such as solar cells, integrated circuits, semiconductors and the like, is one of key materials of high and new technology industries such as photovoltaic power generation, electronic information and the like, and has an important strategic position in terms of energy, information and national safety.

According to the existing literature research, the current foreign research units are mainly enterprises such as Sumitomo, Toshiba and JASTEC, etc. of Japan superconducting technology company. Although the related research on domestic monocrystalline silicon is started with Japan, the production technology level is still relatively low in the present general. In recent years, related patents such as CN103106994A, CN110136915A and ZL201922296007.3 are applied for protection in China. However, most of the current magnets have two problems as follows: (1) the magnet is not shielded by electrician pure iron, and (2) the thicker electrician pure iron is used for shielding. The magnet which is not magnetically shielded is bound to cause overlarge magnetic leakage due to the strong magnetic field of the magnetic control pulling single crystal superconducting magnet, so that the electric equipment around the magnet is influenced, even the magnetic field distribution of the adjacent magnet is influenced, and the high-quality growth of the single crystal silicon is influenced. And the magnetic control that adopts the individual layer thick electrician's pure iron to carry out the magnetic screen draws single crystal magnet, needs thick electrician's pure iron just can reduce the magnetic leakage to reasonable level, and the electrician's pure iron of so not only waste, also can produce too big electromagnetic force between the electrician's pure iron of excessive thickness and the superconducting magnet coil for superconducting magnet operating stability receives certain influence.

Disclosure of Invention

The embodiment of the invention provides a magnetic control single crystal pulling superconducting magnet and a magnetic shielding method, which are used for solving the problems that in the prior art, a single-layer thicker electrical pure iron is used for magnetic shielding, the electrical pure iron is wasted, and the running stability of the superconducting magnet is influenced.

On one hand, the embodiment of the invention provides a magnetic control single crystal pulling superconducting magnet, which comprises a shielding structure and a superconducting coil;

the shielding structure includes: the magnetic shielding iron yoke comprises a magnetic shielding iron yoke upper plate, a magnetic shielding iron yoke lower plate and a magnetic shielding iron yoke barrel, wherein the magnetic shielding iron yoke upper plate and the magnetic shielding iron yoke lower plate are respectively connected to two ends of the magnetic shielding iron yoke barrel, and the magnetic shielding iron yoke barrel is of a multilayer structure;

the superconducting coil is disposed inside the magnetic shield structure.

In one possible implementation manner, the magnetic shielding yoke upper plate and the magnetic shielding yoke lower plate are parallel to each other, two ends of the magnetic shielding yoke cylinder are vertically connected to the magnetic shielding yoke upper plate and the magnetic shielding yoke lower plate respectively, and the magnetic shielding yoke cylinder is located at outer side edge positions of the magnetic shielding yoke upper plate and the magnetic shielding yoke lower plate.

In one possible implementation, the magnetic shield yoke upper plate, the magnetic shield yoke lower plate and the magnetic shield yoke cylinder are all made of electrical pure iron.

In a possible implementation manner, the magnetic shielding device further comprises a dewar, wherein the dewar is a hollow closed structure, the dewar is arranged inside the magnetic shielding structure, and the superconducting coil is arranged inside the dewar.

In one possible implementation, the dewar includes an outer dewar and an inner dewar; the outer Dewar is arranged at one side of the shielding structure close to the magnetic shielding iron yoke cylinder, and the inner Dewar is arranged at the position close to the axis of the shielding structure.

In one possible implementation, the inner dewar is made using a non-magnetic material.

In a possible implementation mode, the device further comprises a cold shield, wherein the cold shield is of a hollow structure, the cold shield is arranged inside the Dewar, and the superconducting coil is arranged inside the cold shield.

In a possible implementation mode, the refrigerator is arranged outside the shielding structure, the refrigeration output end of the refrigerator is connected with a primary cold head, and the primary cold head is connected with the cold shield.

In one possible embodiment, the superconducting coil is wound on a coil former.

On the other hand, the embodiment of the invention also provides a magnetic shielding method of the magnetic control single crystal pulling superconducting magnet, which comprises the following steps:

determining the layer number of the magnetic shielding structure;

assembling a magnetic shielding structure;

the superconducting coils are arranged inside the magnetic shielding structure.

The magnetic control single crystal pulling superconducting magnet and the magnetic shielding method have the following advantages:

by adopting the multilayer optimized magnetic shielding structure, the magnetic leakage of the magnet is further reduced on the basis of saving electrician pure iron, so that the safe and stable operation of electrical equipment around the superconducting magnet for magnetically controlling and pulling the single crystal is met. Meanwhile, the thickness of the single-layer magnetic shielding structure is smaller, the risk of the problem of the induced running stability of the magnet due to overlarge electromagnetic acting force between the magnetic shielding and the superconducting coil caused by the single-layer thicker electrician pure iron magnetic shielding structure can be reduced, the stability of the superconducting magnet for magnetic control crystal pulling is improved, and the production efficiency and the stability are ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a magnetic control single crystal pulling superconducting magnet according to an embodiment of the present invention;

fig. 2 is a flowchart of a method for magnetically pulling a single crystal to form a superconducting magnetic shield according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a magnetron-pulled single crystal superconducting magnet according to an embodiment of the present invention. The embodiment of the invention provides a magnetic control single crystal pulling superconducting magnet, which comprises a shielding structure and a superconducting coil 410;

the shielding structure includes: the magnetic shielding iron yoke comprises a magnetic shielding iron yoke upper plate 100, a magnetic shielding iron yoke lower plate 110 and a magnetic shielding iron yoke barrel 120, wherein the magnetic shielding iron yoke upper plate 100 and the magnetic shielding iron yoke lower plate 110 are respectively connected to two ends of the magnetic shielding iron yoke barrel 120, and the magnetic shielding iron yoke barrel 120 is of a multilayer structure;

the superconducting coils 410 are disposed inside a magnetic shield structure.

Illustratively, the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110 are both circular ring-shaped plates, and both are the same size. The magnetic shield yoke upper plate 100 is positioned right above the magnetic shield yoke lower plate 110, the upper and lower ends of the magnetic shield yoke cylinder 120 are respectively connected to the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110, and the magnetic shield yoke cylinder 120 is connected to the outer edge positions of the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110, so that the whole shielding structure is formed into a cylindrical hollow cylinder shape. The superconducting coil 410 is disposed inside the shielding structure, and under the action of the magnetic shielding iron yoke barrel 120, the strong magnetic field generated by electrifying the superconducting coil 410 can be limited inside the shielding structure, and no or little leakage flux is generated.

In one possible embodiment, the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110 are parallel to each other, both ends of the magnetic shield yoke cylinder 120 are vertically connected to the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110, respectively, and the magnetic shield yoke cylinder 120 is located at the outer edge positions of the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110.

Illustratively, the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110 are in a horizontal state, and thus the magnetic shield yoke barrel 120 is in a vertical state after the magnetic shield yoke barrel 120 is vertically connected between the magnetic shield yoke upper plate 100 and the magnetic shield yoke lower plate 110. And a gap is provided between the multi-layered structure of the magnetic shield yoke cylinder 120.

In one possible embodiment, the magnetic shield yoke upper plate 100, the magnetic shield yoke lower plate 110, and the magnetic shield yoke cylinder 120 are all made of electrical pure iron.

Illustratively, the magnetic shield yoke upper plate 100, the magnetic shield yoke lower plate 110 and the magnetic shield yoke barrel 120, which are made of an electrical pure iron material, can effectively block the leakage of the strong magnetic field generated by the superconducting coil 410.

In a possible embodiment, dewar 200 is further included, dewar 200 is a hollow closed structure, dewar 200 is disposed inside a magnetic shielding structure, and superconducting coil 410 is disposed inside dewar 200.

Illustratively, the interior of the dewar 200 is evacuated to reduce heat exchange between the superconducting coil 410 and the exterior of the dewar 200, so that the superconducting coil 410 can be always below the superconducting critical temperature.

In one possible embodiment, dewar 200 includes an outer dewar and an inner dewar 130; the outer dewar is disposed inside the shield structure at a side close to the magnetic shield yoke cylinder 120, and the inner dewar 130 is disposed at a position close to the axis of the shield structure.

Illustratively, since the single crystal furnace or the like is disposed at the axial center of the shielding structure, and the strong magnetic field generated by the superconducting coil 410 needs to act on the single crystal furnace or the like, the inner dewar 130 located near the axial center of the shielding structure is made of a non-magnetic material to avoid shielding the magnetic field, so that the magnetic field can smoothly penetrate and act on the device at the axial center of the shielding structure.

In a possible embodiment, the cold shield 300 is further included, the cold shield 300 is a hollow structure, the cold shield 300 is arranged inside the dewar 200, and the superconducting coil 410 is arranged inside the cold shield 300.

Illustratively, the cold shield 300 is coupled to a primary cold head 510, the primary cold head 510 is coupled to a refrigeration output of the refrigerator 500, and the refrigerator 500 is disposed outside of the shielding structure. In an embodiment of the present invention, chiller 500 is a G-M chiller. The refrigerator 500 transfers the low temperature to the cold shield 300 through the primary cold head 510, thereby reducing the temperature of the cold shield 300, so that the superconducting coil 410 inside the cold shield 300 is always in a low temperature state, and ensuring that the superconducting coil 410 has a good working state. Meanwhile, since the whole cold shield 300 is located inside the vacuum dewar 200, the cold shield 300 does not exchange heat with the outside of the dewar 200, so that the cold shield 300 can be always in a low temperature state.

In one possible embodiment, the superconducting coils 410 are wound around the bobbin 400.

Illustratively, the bobbin 400 is an O-shaped structure, and the bobbin 400 of the O-shaped structure has a curvature, i.e., forms a saddle-like shape. In the embodiment of the present invention, the number of the bobbin 400 is two, the two bobbins 400 have the same structure and are symmetrically disposed at two sides of the interior of the cold shield 300, the two bobbins 400 are connected together by the cold conducting connection structure 520, and the cold conducting connection structure 520 is installed on the inner side surface of the cold shield 300. The coil bobbin 400 not only provides structural support for the superconducting coil 410 and resists deformation of the superconducting coil 410 caused by electromagnetic force generated when the superconducting magnet operates, but also serves as a cold conduction structure of the superconducting coil 410, the coil bobbin 400 is in contact with the cold conduction structure on the inner bottom surface of the shielding structure, namely the top surface of the lower plate 110 of the magnetic shielding iron yoke, the cold conduction structure is connected with the secondary cold head, and the secondary cold head is connected with the primary cold head 510, so that low temperature can be transmitted to the superconducting coil 410. Meanwhile, the primary cold head 510 is also connected to the cold shield 300, and a low temperature environment is also provided for the superconducting coil 410 through the cold shield 300.

The embodiment of the invention also provides a magnetic shielding method of the magnetic control single crystal pulling superconducting magnet, as shown in fig. 2, the method comprises the following steps:

s200, determining the number of layers of the magnetic shielding structure;

s210, assembling a magnetic shielding structure;

s220, arranging the superconducting coil 410 in the magnetic shielding structure.

For example, the number of layers and the thickness of the shielding structure, specifically, the magnetic shielding iron yoke barrel 120, may be optimally designed according to related design parameters in combination with the magnetization curve of the electrical pure iron, so as to meet the magnetic leakage requirement of the superconducting magnet. After the number of magnetic shielding layers, specifically the number of magnetic shielding iron yoke barrels 120, is determined, the magnetic shielding structure can be assembled. Then, the dewar 200, the cold shield 300, the coil bobbin 400, the superconducting coil 410, and the refrigerator 400 are sequentially mounted, and the mounting of the entire superconducting magnet is completed. Before use, the interior of the Dewar 200 needs to be vacuumized, and the preferred vacuum degree needs to reach 10^-2Pa and then the refrigerator 500 is started to bring the superconducting coil 410 gradually to the operating temperature. And finally, electrifying and exciting the superconducting coil 410, and producing high-purity monocrystalline silicon by combining a monocrystalline furnace after the current reaches a required value.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.