TWI622674B - Seed chuck and crystal seed growth fruance - Google Patents

Abstract

The invention discloses a seed crystal chuck and a straight-drawing single crystal furnace. The seed crystal chuck is provided with a hollow structure, and the hollow structure penetrates the upper and lower ends of the seed crystal chuck. It is applied to a straight-drawing single crystal furnace, so that the inert protective gas (such as argon) in the straight-drawing single crystal furnace can cool the middle part of the head of the ingot through the hollow structure, and dissipate heat from the edge of the ingot. The speed is kept consistent, so that the entire ingot is cooled uniformly, the phenomenon of rapid heat dissipation at the edge of the ingot and slow heat dissipation in the middle is overcome, and the crystal quality of the ingot is improved. In addition, the outer diameter of the seed chuck is equal to the diameter of a crystal rod, which is conducive to suppressing the upward radiation heat transfer from the lower end of the straight-drawing single crystal furnace, reducing the heat loss upward through the hollow structure, and reducing the power consumption of the crystal growth. Steady control of the thermal field temperature distribution during the growth process is beneficial to the growth of the ingot and improves the crystal quality of the ingot.

Description

Seed chuck and straight pull single crystal furnace

The invention relates to the field of crystal rod growth, in particular to a seed crystal chuck and a straight-drawing single crystal furnace.

Monocrystalline silicon, as a semiconductor material, is generally used in the manufacture of integrated circuits and other electronic components. Most of the semiconductor single crystal silicon is manufactured by the direct pull method. For the single crystal silicon growth method using the direct pull method, please refer to FIG. 1a to FIG. 1c. During the growth of the single crystal silicon, an inert gas such as argon is used as a protective gas (Figure The thick black arrows in 1a, 1b, and 1c indicate the direction of the argon gas flow.) Polycrystalline silicon is placed in a quartz crucible 10 and heated to melt into a silicon melt 11. A seed crystal 12 with a specific crystal orientation is fixed in the seed crystal holder. The lower end of the head 13 and the upper end of the seed crystal chuck 13 are connected to a linkage mechanism 15 through a connecting rod 14. The linkage mechanism 15 is used to control the movement of the seed crystal 12. First, the seed crystal 12 is fused to the silicon melt 11 (as shown in FIG. 1 a), and the seeding stage is started. Then, the single crystal silicon is adjusted by adjusting the temperature of the silicon melt 11 and the upward speed of the seed crystal 12. 16 grows up after the shoulder-releasing phase and the shoulder-turning phase (as shown in Figure 1b and Figure 1c).

However, the crystal quality of the front stage (about 100 mm height) of the single crystal silicon 16 formed in the prior art is poor, which cannot meet the actual needs, resulting in greater waste.

The technical problem to be solved by the present invention is to provide a seed chuck and a straight pull single The crystal furnace can improve the crystal quality of the crystal rod, increase the utilization rate of the entire crystal rod and reduce the cost when the crystal rod is prepared by the direct drawing method.

In order to solve the above technical problems, the seed chuck provided by the present invention includes: a hollow structure is arranged in the seed chuck, and the hollow structure penetrates the upper and lower ends of the seed chuck.

Further, in the seed chuck, a shape of a cross section of the hollow structure in a height direction is a quadrangle.

Optionally, in the seed chuck, the quadrangle is an inverted trapezoid.

Further, in the seed chuck, a cross-sectional shape of the hollow structure in a width direction is circular or polygonal.

Optionally, in the seed chuck, the number of sides of the polygon is 3-12.

Further, in the seed chuck, an outer diameter of the seed chuck is equal to a diameter of a crystal rod.

Further, in the seed chuck, the size of the outer diameter is 100 mm-600 mm.

Further, in the seed chuck, a maximum value of an inner diameter of the seed chuck is 1/3 to 2/3 of the outer diameter.

Further, in the seed chuck, a minimum value of an inner diameter of the seed chuck is 1/5 to 1/3 of the outer diameter.

Optionally, in the seed chuck, the height of the seed chuck is 100 mm-600 mm.

Further, in the seed chuck, the shape of the seed chuck is a cylinder or a prism.

Further, in the seed chuck, the number of sides of the prism is 3-12.

Further, in the seed chuck, a central axis of the hollow structure coincides with a central axis of the seed chuck.

Further, in the seed chuck, the material of the seed chuck is molybdenum or graphite.

Optionally, in the seed chuck, the seed chuck further includes a first connection structure, and the first connection structure is located at a bottom portion or a lower half of an inner sidewall of the seed chuck.

Further, in the seed chuck, the first connection structure is in a “T” shape.

Optionally, in the seed chuck, the seed chuck further includes a second connection structure, and the second connection structure is located on the top or the upper half of the inner side wall of the seed chuck.

Further, in the seed chuck, the second connection structure is in a “T” shape.

According to another aspect of the present invention, the present invention also provides a straight-drawing single crystal furnace including the above-mentioned seed chuck.

Further, in the straight-drawing single crystal furnace, the straight-drawing single crystal furnace further includes a linkage mechanism, and an upper end of the seed crystal chuck is connected to the linkage mechanism through a connecting rod, and the seed crystal clamp A seed crystal is fixed at the lower end of the head, and the linkage mechanism is used to control the movement of the seed crystal.

Further, in the straight-drawing single crystal furnace, the seed crystal is fixed to a lower end of the seed crystal chuck through a seed crystal shaft or a first steel wire.

Further, in the straight-drawing single crystal furnace, the seed is passed through a second steel wire. The upper end of the crystal chuck is connected to the connecting rod.

In the present invention, a hollow structure is provided in the seed chuck, and the hollow structure penetrates the upper and lower ends of the seed chuck, and is applied to a straight-drawing single crystal furnace, so that the straight-drawing single crystal furnace is used. The inert protective gas (such as argon) can cool the middle part of the head of the ingot through the hollow structure, keeping the same heat dissipation speed as the edge of the ingot, so that the entire ingot is radiated uniformly, and the heat dissipation at the edge of the ingot is overcome quickly. Slow phenomenon improves the crystal quality of the ingot.

Further, the shape of the cross-section of the hollow structure in the height direction is an inverted trapezoid, that is, the upper bottom area of the hollow structure is larger than the bottom bottom area. , Reducing heat loss through the hollow structure, reducing the power consumption of the crystal growth, stably controlling the thermal field temperature distribution of the crystal growth process, facilitating the growth of the crystal rod, and improving the crystal quality of the crystal rod. On the other hand, the upper and lower areas of the hollow structure of the seed chuck should be large, so that more shielding gas can pass through the hollow structure, and the purpose of cooling the middle part of the head of the crystal rod is better achieved. Ingots with better crystal quality.

Furthermore, the outer diameter of the seed chuck is equal to the diameter of a crystal rod. Compared with the existing seed chuck, the outer diameter of the seed chuck is increased, and a straight-drawing single crystal furnace can be suppressed. The lower end radiates heat upward, reduces the power consumption of the crystal, and stably controls the thermal field temperature distribution of the crystal growth process, which is beneficial to the growth of the crystal rod and improves the crystal quality of the crystal rod. In particular, in the initial stage of the formation of the ingot, the upward lifting speed of the seed crystal changes greatly, which makes the temperature distribution of the thermal field in the Czochralski single crystal furnace fluctuate greatly. By increasing the outer diameter of the seed crystal chuck, it can be greatly reduced. The heat is lost, which reduces the power consumption at the beginning of the growth of the ingot, so that the temperature of the grown crystal is increased in advance during the shoulder turning stage. And reduce costs.

10‧‧‧Quartz Crucible

11‧‧‧ Silicon Melt

12‧‧‧ Seed

13‧‧‧seed chuck

14‧‧‧ connecting rod

15‧‧‧ Linkage

16‧‧‧ Monocrystalline

20‧‧‧Quartz Crucible

21‧‧‧ silicon melt

22‧‧‧ Seed

23‧‧‧seed chuck

A‧‧‧ hollow structure

231‧‧‧First connection structure

232‧‧‧Second connection structure

24‧‧‧ connecting rod

25‧‧‧ Linkage

1a to 1c are schematic structural diagrams of a direct-drawing single crystal furnace in the prior art; FIG. 2a is a three-dimensional structural diagram of the seed chuck in Embodiment 1 of the present invention; and FIG. 2b is a perspective view of the first embodiment of the present invention. The sectional structure view of the seed chuck is shown in FIG. 3a to FIG. 3c are schematic structural diagrams of the straight-drawing single crystal furnace in Embodiment 1 of the present invention; and FIG. 4 is a perspective view of the seed chuck in Embodiment 2 of the present invention. Structural view; FIG. 5 is a perspective structural view of the seed chuck in Embodiment 3 of the present invention.

As described in the conventional art, there is a problem in the prior art that the crystal quality of the front stage (about 100 mm height) of the single crystal silicon 16 is poor. The applicant found through research that, as shown in FIG. 1a to FIG. 1c, in the prior art, when the single-crystal silicon is prepared by the straight-draw method, the commonly used seed chuck 13 is a solid cylinder, and at the seeding stage of the crystal growth, At the turn of the shoulder stage, the flow direction of the inert gas such as argon around the single crystal silicon 16 will be affected by the solid seed chuck 13, the middle portion of the single crystal silicon 16 will have a small argon gas flow, and the edge portion will be argon. The air flow is large (the direction of the argon gas flow is shown by the thick black arrows in Figures 1a, 1b, and 1c). Therefore, the edge of the single crystal silicon 16 will dissipate heat quickly, and the heat dissipation in the middle will be slow. Uniform, so that the solid-liquid interface (that is, the interface of the silicon melt 11 and the single crystal silicon 16) is convex toward the crystal, resulting in poor crystal quality; In addition, because the diameter of the commonly used seed chuck 13 is small, In the seeding stage and the shoulder releasing stage, due to the large change in the upward lifting speed of the seed crystal 12, the thermal field temperature distribution in the straight-type single crystal silicon furnace device fluctuates greatly, and a large amount of heat will be dissipated upward from the lower end of the straight-type single crystal furnace. (The thin line arrows in Figures 1a, 1b and 1c indicate the direction of heat loss) The growth of the preceding single-crystal silicon, monocrystalline silicon so that further pre-stage of the crystal quality deterioration can not meet the actual demand, resulting in greater waste.

Based on the above research and discovery, the present invention provides a seed chuck. A hollow structure is disposed in the seed chuck, and the hollow structure penetrates the upper and lower ends of the seed chuck.

Correspondingly, the present invention also provides a straight-drawing single crystal furnace using the seed crystal chuck.

In the present invention, a hollow structure is provided in the seed chuck, and the hollow structure penetrates the upper and lower ends of the seed chuck, and is applied to a straight-drawing single crystal furnace, so that the straight-drawing single crystal furnace is used. The inert protective gas (such as argon) can cool the middle part of the head of the ingot through the hollow structure, keeping the same heat dissipation speed as the edge of the ingot, so that the entire ingot is radiated uniformly, and the heat dissipation at the edge of the ingot is overcome quickly. Slow phenomenon improves the crystal quality of the ingot.

In the following, the seed chuck and the straight-drawing single crystal furnace of the present invention will be described in more detail with reference to flowcharts and schematic diagrams, which show the preferred embodiments of the present invention. It should be understood that those skilled in the art can modify the present invention described herein. While still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as widely known to those skilled in the art, and not as a limitation on the present invention.

The invention is described in more detail by way of example in the following paragraphs with reference to the drawings. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and all use inaccurate proportions, which are only used to facilitate and clearly assist the description of the embodiments of the present invention.

The examples of the seed chuck and the straight-drawing single crystal furnace are listed below to clearly explain the content of the present invention. It should be clear that the content of the present invention is not limited to the following embodiments. Improvements in conventional technical means are also within the scope of the present invention.

Example 1:

Please refer to FIG. 2a and FIG. 2b. FIG. 2a is a schematic diagram of the three-dimensional structure of the seed chuck according to Embodiment 1 of the present invention, and FIG. 2b is a schematic diagram of its cross-sectional structure. In this embodiment, a hollow structure A is provided in the seed chuck 23, and the hollow structure A penetrates the upper and lower ends of the seed chuck 23 to form an air flow in the seed chuck 23. Conductable structure. Preferably, the shape of the seed chuck 23 is a cylinder, and the shape of the cross-section (ie, vertical cross-section) of the hollow structure A in the height direction is an inverted trapezoid, and the hollow structure A is in the width direction. The shape of the cross section (that is, the cross section) is circular. In order to maintain the seed chuck 23 in a relatively stable state, the central axis of the hollow structure A coincides with the central axis of the seed chuck 23. Preferably, in a straight-drawing single crystal furnace, the outer diameter D1 of the seed chuck is equal to the diameter of the required ingot, for example: the diameter of the required ingot is 150mm, 300mm, 450mm, etc., correspondingly, The outer diameter D1 is designed to be 150mm, 300mm, 450mm, etc., and the size of the outer diameter D1 may be in the range of 100mm-600mm; meanwhile, the maximum inner diameter D2 _{max of} the seed chuck 23 may be The outer diameter D1 is 1/3 to 2/3, for example, the maximum inner diameter D2 _max is 50mm, 100mm, 150mm, 200mm, 300mm, etc .; the minimum inner diameter D2 _{min of} the seed chuck 23 may be the The outer diameter D1 is 1/5 to 1/3, for example, the minimum inner diameter D2 _min may be 30mm, 60mm, 90mm, 150mm, etc .; the height H of the seed chuck 23 may be 100mm-600mm. The seed chuck 23 outer diameter D1, the maximum inner diameter D2 _max, and the minimum inner diameter D2 _min is set to match the height H, so that the best crystal quality of the ingot. The material of the seed chuck 23 may be a material having high temperature resistance and high strength, such as metallic molybdenum or graphite.

Of course, the above-mentioned seed chuck 23 needs to be used in combination with other devices in practical applications. Therefore, the seed chuck 23 further includes a first connection structure 231 and a second connection structure 232. Preferably, the first connection structure 231 is located at the bottom of the seed chuck 23, in order to To balance the forces, the first connection structure 231 is designed in a “T” shape; the second connection structure 232 is located on the top of the seed chuck 23 and is also designed in a “T” shape. For example, when the above-mentioned seed chuck 23 is applied to a straight-pull single crystal furnace, since the commonly used seed crystal is generally a cylinder or a rectangular parallelepiped, one or more notches are provided on it, so it can directly pass through a seed axis. Or the first metal wire (such as the first steel wire) fixes the seed crystal on the first connecting structure 231; at the same time, in order to control the movement of the seed crystal, a seed crystal shaft or a second metal can be transmitted through A wire (such as a second steel wire) and a second connection structure 232 connect the seed crystal chuck 23 with a connecting rod, and then the connecting rod connects a linkage structure, and the linkage mechanism controls the movement of the seed crystal. In fact, in other embodiments, the “ten” shape of the first connection structure 231 and the second connection structure 232 may also be designed on the lower half and the upper half of the inner side wall of the seed chuck 23, respectively. Similarly, the seed crystal chuck 23 can be fixed to the seed crystal 22 and the seed crystal chuck 23 is connected to the connecting rod. Obviously, the first connection structure 231 may also be other structures matching the seed crystal, such as grooves, small holes, etc., and the seed crystal 22 may be fixed by a pin; similarly, the second The connecting structure 232 may also be another structure designed to be matched with the connecting rod. The present invention does not limit the first connection structure 231 and the second connection structure 232, and they may also include other structures known to those of ordinary skill in the art, and details are not described herein.

In order to further clearly describe and explain the content of the present invention, the growth process of preparing a single crystal silicon by a direct drawing method is taken as an example to describe in detail the beneficial effect of the seed chuck applied to a direct drawing single crystal furnace.

Please refer to FIG. 3a to FIG. 3c, which are schematic structural diagrams of the straight-drawing single crystal furnace corresponding to an initial stage, a shoulder-releasing stage, and a shoulder-turning stage of preparing a single-crystal silicon by a straight-drawing method. In the process of preparing single crystal silicon by the direct pulling method, an inert gas such as argon is used as a protective gas, and an inert gas such as Argon, combined with vacuum pumping, forms an argon flow under a reduced-pressure atmosphere in a straight-drawing single crystal furnace (the thick black arrows in Figs. 3a to 3c indicate the direction of argon flow). The flow of argon gas can take away the volatile oxides of high temperature molten polycrystalline silicon to prevent the oxide particles from falling into the silicon melt and then moving to the solid-liquid interface, destroying the consistency of the monocrystalline silicon atom arrangement; on the other hand, it can timely Take away the heat from the surface of the single crystal silicon, promote the heat dissipation and cooling of the single crystal silicon, and increase the vertical temperature gradient of the single crystal silicon, which is conducive to the growth of the single crystal silicon. Generally, the pressure of the decompressed atmosphere during the preparation of single crystal silicon is 12 Torr-20 Torr, and the flow rate of argon gas is 45 slpm-80 slpm (standard liter per minute, that is, standard liter per minute).

The specific preparation process is as follows: first, polycrystalline silicon is loaded into the quartz crucible 20, and a seed crystal 22 having a specific crystal orientation is fixed at the lower end of the seed crystal chuck 23, and the seed crystal 22 is formed by a certain crystal orientation. Silicon single crystal is cut or drilled, and the commonly used crystal directions are <100>, <111>, <110>, <511> and so on. The seed crystal 22 is generally a cylinder or a rectangular parallelepiped, and one or more notches are provided on the seed crystal. Therefore, the seed crystal 22 or the first steel wire (illustration omitted in the figure) and the first connection structure can be passed through. 231 (as shown in FIG. 2) fixes the seed crystal 22 to the lower end of the seed chuck 23; the upper end of the seed chuck 23 is connected to a linkage mechanism 25 through a connecting rod 24 to control the The movement of the seed crystal 22 is to close the chamber of the straight-drawing single crystal furnace and evacuate it. Then, the polycrystalline silicon is heated and melted through the graphite heating element (the diagram is omitted in the figure), and the polycrystalline silicon is completely melted to form a silicon melt 21 Then, gradually lower the silicon melt temperature to near the melting point of the silicon.

Then, the seed crystal chuck 23 is rotated by the connecting rod 24 through the linkage mechanism 25, and the seed crystal 22 is slowly lowered to be fused with the silicon melt 21 (as shown in FIG. 3a). (Shown), that is, the process of the initial stage of the single crystal silicon is completed; then, the seed crystal 22 is pulled up at a certain speed through the linkage mechanism 25 to enter the seeding process, the main role of the seeding process In order to eliminate the dislocation defect caused by single crystal silicon due to thermal shock, the supercooling degree of the leading edge of the crystal is used to drive the silicon atoms to sequentially arrange on the silicon solid on the solid-liquid interface to form the single crystal silicon 26.

When the single crystal silicon 26 is raised to a certain height, the speed of pulling up the seed crystal 22 is reduced, and the temperature of the silicon melt 21 is slightly reduced. The temperature is lowered to promote the lateral growth of the single crystal silicon 26 Even if the diameter of the single crystal silicon 26 is increased, this process is called a shoulder-releasing stage (as shown in FIG. 3b).

In the above process, the flat solid-liquid interface and stable thermal field temperature distribution are the key factors affecting the quality of single crystal silicon. Therefore, in the embodiment of the invention, a hollow structure A is provided in the seed chuck 23, and the shape of the vertical section of the hollow structure A is an inverted trapezoid, that is, the upper area area of the hollow structure A is greater than the lower area area. It can make relatively more inert protective gas (such as argon) in the straight-drawing single crystal furnace cool the middle part of the head of the single crystal silicon 26 through the hollow structure A, and dissipate heat from the edge of the single crystal silicon 26. Keep the speed uniform, make the whole single crystal silicon dissipate uniformly, overcome the phenomenon that the edge of the single crystal silicon dissipates fast, and the heat dissipation in the middle is slow, get a good solid-liquid interface, and increase the vertical temperature gradient of the single crystal silicon, improve the crystal quality. In addition, because the speed of pulling up the seed crystal 22 in the above process changes greatly, and the temperature of the silicon melt 21 also changes, the temperature distribution of the thermal field in the straight-drawing single crystal furnace also fluctuates greatly, but In the embodiment of the present invention, since the outer diameter of the seed crystal chuck 23 is equal to the diameter of the single crystal silicon to be formed subsequently, the large-sized seed crystal chuck 23 can suppress the upward radiation of the lower end of the straight pull single crystal furnace. Heat transfer (the thin line arrows in Figures 3a to 3c indicate the direction of heat radiation), and the lower bottom area of the hollow structure A is small, which is also to reduce the heat loss upward through the hollow structure A, which can reduce the single crystal well The heat loss in the early stage of silicon stabilizes the thermal field temperature distribution during the growth process of the silicon, reduces the power consumption in the early stage of single crystal silicon growth, and is beneficial to the subsequent growth of single crystal silicon.

Next, when the diameter of the single crystal silicon 26 is increased to a target diameter (about 10 mm lower than the target diameter), the temperature of the silicon melt 21 is increased by increasing the heating power of the graphite heating element, and the seed crystal is adjusted at the same time. The speed of the upward pull, the speed of rotation, and the speed of rotation of the quartz crucible suppress the lateral growth of the single crystal silicon 26 and promote its vertical growth, so that the single crystal silicon 26 grows to approximately the same diameter. This stage is called Turn shoulder stage (as shown in Figure 3c). In order to promote the lateral growth of the single crystal silicon 26 in the previous stage (that is, the shoulder-releasing stage), the temperature of the silicon melt 21 is reduced, and the outer diameter of the seed chuck 23 in the embodiment of the present invention is reduced. It has the same diameter as the required single crystal silicon, which greatly reduces the heat loss at the lower end of the straight-drawing single crystal furnace. Therefore, when entering the turning shoulder stage, the actual temperature of the straight-drawing single crystal furnace will be compared with the actual temperature in the prior art. High, that is, the starting temperature of the shoulder stage in the actual process is increased in advance, which can reduce the length of the bad part of the front part of the single crystal silicon 26, which is conducive to the growth of the subsequent single crystal silicon, and improves the utilization rate of the entire single crystal silicon lower the cost.

It then entered the equal-diameter growth process, which is the main stage of single crystal silicon growth, growing for tens of hours or even more than a hundred hours. Finally, when there is not much silicon melt 21 in the quartz crucible 20, the diameter of the single crystal silicon 26 is changed to an inverted cone by accelerating the upward lifting speed of the seed crystal 22 and appropriately increasing the heating power. When the cone tip is small enough, it will detach from the silicon melt 21, at which time the growth process of the single crystal silicon ends. When the single crystal silicon 26 cools to near room temperature, the single crystal silicon 26 can be removed.

In this embodiment, a hollow structure A is provided in the seed chuck, and the hollow structure A is applied to a straight-drawing single crystal furnace, so that an inert protective gas (such as argon) in the straight-drawing single crystal furnace can pass through. The hollow structure A cools the middle part of the monocrystalline silicon head to keep the same heat dissipation speed as the edge of the monocrystalline silicon, so that the entire monocrystalline silicon can dissipate heat uniformly, and the heat dissipation of the edge of the monocrystalline silicon can be overcome quickly. The phenomenon of slow heat dissipation forms a good solid-liquid interface and improves the crystal quality of single crystal silicon.

Further, the shape of the cross section of the hollow structure A in the height direction is an inverted trapezoid, that is, the upper bottom area of the hollow structure is larger than the lower bottom area. On the one hand, it is beneficial to suppress the upward radiation transmission of the lower end of the straight-drawing single crystal furnace. Heat, reduces the heat dissipation upward through the hollow structure A, reduces the power consumption of the single crystal silicon growth, and stably controls the thermal field temperature distribution of the single crystal silicon growth process, which is beneficial to the growth of the single crystal silicon and improves the Crystal quality. On the other hand, the upper and lower areas of the hollow structure A of the seed chuck should be large, so that more shielding gas can pass through the hollow structure and better achieve the purpose of cooling the middle portion of the single crystal silicon head. Single crystal silicon with better crystal quality was obtained.

Furthermore, the outer diameter of the seed chuck is equal to the diameter of the single crystal silicon. Compared with the existing seed chuck, the outer diameter of the seed chuck is increased, and the straight pull single can be suppressed. The lower end of the furnace radiates heat upward, reduces the power consumption of the single crystal silicon growth, and stably controls the thermal field temperature distribution of the single crystal silicon growth, which is beneficial to the growth of the single crystal silicon and improves the crystal quality of the single crystal silicon. In particular, in the initial stage of the formation of the single crystal silicon, the upward lifting speed of the seed crystal changes greatly, so that the thermal field temperature distribution in the straight-pull single crystal furnace fluctuates greatly. By increasing the outer diameter of the seed crystal chuck, it can greatly increase Reduce heat dissipation, reduce power consumption in the early stage of growth of single crystal silicon, increase the temperature of the growth of the crystal in the shoulder stage in advance, reduce the bad quality of the front part of the single crystal silicon, which is conducive to the subsequent growth of the single crystal silicon and improve the entire single crystal silicon. Utilization and cost reduction of crystalline silicon.

Example 2:

Please refer to FIG. 4, which illustrates a three-dimensional structure view of the seed chuck according to the embodiment. The structure of the seed chuck of the second embodiment is basically the same as that of the seed chuck of the first embodiment. Both of them have a cylindrical structure, the outer diameter is equal to the diameter of the required crystal rod, and the hollow structure B of The shapes of the vertical sections are inverted trapezoids, and the difference is that the shape of the cross section of the hollow structure B of the seed chuck 23 in the second embodiment is a hexagon. In other embodiments, the shape of the cross section of the hollow structure may also be other polygons, such as a triangle, a quadrangle, an octagon, a dodecagon, etc., and the number of sides of the polygon may be 3-12.

Therefore, when the seed chuck 23 is used in a straight-drawing single crystal furnace in this embodiment, it also has the beneficial effects as described in the first embodiment.

Example 3:

Please refer to FIG. 5, which illustrates a three-dimensional structure diagram of the seed chuck according to the embodiment. The structure of the seed chuck of the third embodiment is basically the same as that of the seed chuck of the first embodiment, and the hollow structure A of the two is the same. The shape of the vertical cross section of the hollow structure A is an inverted trapezoid. The shapes of the cross-sections of the hollow structures A are all circular. The difference is that the shape of the seed chuck 23 in the third embodiment is a hexagonal prism, and the longest pair of the bottom of the hexagonal prism is opposite. The angle (that is, the outer diameter of the seed chuck 23) is equal to the diameter of the desired crystal rod. In other embodiments, the shape of the seed chuck 23 may be other prisms, and the number of sides of the prisms may be 3-12.

Therefore, when the seed chuck 23 is used in a straight-drawing single crystal furnace in this embodiment, the beneficial effects as described in Embodiment 1 can also be achieved.

In summary, the present invention provides a hollow structure in the seed chuck, and the hollow structure penetrates the upper and lower ends of the seed chuck, and is applied to a straight-drawing single crystal furnace, so that the straight-drawing single The inert protective gas (such as argon) in the crystal furnace can cool the middle part of the head of the crystal rod through the hollow structure, keeping the same heat dissipation speed as the edge of the crystal rod, making the entire crystal rod uniformly dissipate heat, and overcoming the rapid cooling of the edge of the crystal rod. The phenomenon of slow heat dissipation in the middle improves the crystal quality of the ingot.

Further, the shape of the cross section of the hollow structure in the height direction is an inverted trapezoid, that is, the upper bottom area of the hollow structure is larger than the lower bottom area. On the one hand, it is beneficial to suppress the upward radiation heat transfer from the lower end of the straight-drawing single crystal furnace. , Reducing heat loss through the hollow structure, reducing the power consumption of the crystal growth, stably controlling the thermal field temperature distribution of the crystal growth process, facilitating the growth of the crystal rod, and improving the crystal quality of the crystal rod. On the other hand, the upper and lower areas of the hollow structure of the seed chuck should be large, so that more shielding gas can pass through the hollow structure, and the purpose of cooling the middle part of the head of the crystal rod is better achieved. Ingots with better crystal quality.

Furthermore, the outer diameter of the seed chuck is equal to the diameter of a crystal rod. Compared with the existing seed chuck, the outer diameter of the seed chuck is increased, and a straight-drawing single crystal furnace can be suppressed. The lower end radiates heat upward, reduces the power consumption of the crystal, and stably controls the thermal field temperature distribution of the crystal growth process, which is beneficial to the growth of the crystal rod and improves the crystal quality of the crystal rod. In particular, in the initial stage of the formation of the ingot, the upward lifting speed of the seed crystal changes greatly, which makes the temperature distribution of the thermal field in the Czochralski single crystal furnace fluctuate greatly. By increasing the outer diameter of the seed crystal chuck, it can be greatly reduced. The heat is lost, which reduces the power consumption at the beginning of the growth of the ingot, so that the temperature of the grown crystal is increased in advance during the shoulder turning stage, and the bad quality of the front part of the ingot is reduced, which is conducive to the growth of the subsequent ingot and the utilization of the entire ingot. And reduce costs.

Obviously, the above embodiments are only the preferred embodiments of the present invention. On the basis of the above-mentioned seed chucks, a variety of similar seed chucks can be obtained to avoid crystal rods in the prior art. Uneven heat dissipation and poor quality of the front part of the ingot. Therefore, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (21)

A seed chuck, in which a hollow structure is arranged, the hollow structure penetrates the upper and lower ends of the seed chuck, and the seed chuck further includes a first connection structure, the The first connection structure is located at the bottom or the lower half of the inner side wall of the seed chuck. The seed chuck according to claim 1, wherein a shape of a cross section of the hollow structure in a height direction is a quadrangle. The seed chuck according to claim 2, wherein the quadrangle is an inverted trapezoid. The seed chuck according to claim 1, wherein a shape of a cross section of the hollow structure in a width direction is a circle or a polygon. The seed chuck according to claim 4, wherein the number of sides of the polygon is 3-12. The seed chuck according to any one of claims 1 to 5, wherein an outer diameter of the seed chuck is equal to a diameter of a crystal rod. The seed chuck according to claim 6, wherein the size of the outer diameter is 100mm-600mm. The seed chuck according to claim 7, wherein a maximum value of an inner diameter of the seed chuck is 1/3 to 2/3 of the outer diameter. The seed chuck according to claim 8, wherein the minimum value of the inner diameter of the seed chuck is 1/5 to 1/3 of the outer diameter. The seed chuck according to claim 1, wherein a height of the seed chuck is 100 mm to 600 mm. The seed chuck according to claim 1, wherein the shape of the seed chuck is a cylinder or a prism. The seed chuck according to claim 11, wherein the number of sides of the prism is 3-12. The seed chuck according to claim 1, wherein a central axis of the hollow structure coincides with a central axis of the seed chuck. The seed chuck according to claim 1, wherein the material of the seed chuck is molybdenum or graphite. The seed chuck according to claim 1, wherein the first connection structure has a cross shape. The seed chuck according to claim 1, wherein the seed chuck further comprises a second connection structure, and the second connection structure is located on the top or the upper half of the inner side wall of the seed chuck. The seed chuck according to claim 16, wherein the second connection structure is cross-shaped. A straight-drawing single crystal furnace using the seed chuck according to any one of claims 1-17. The straight-drawing single crystal furnace according to claim 18, wherein the straight-drawing single crystal furnace further includes a linkage mechanism, and an upper end of the seed crystal chuck is connected to the linkage mechanism through a connecting rod, and the seed crystal A seed crystal is fixed at the lower end of the chuck, and the linkage mechanism is used to control the movement of the seed crystal. The straight-drawing single crystal furnace according to claim 19, wherein the seed crystal is fixed to a lower end of the seed crystal chuck through a seed crystal shaft or a first steel wire. The straight-drawing single crystal furnace according to claim 19, wherein an upper end of the seed crystal chuck is connected to the connecting rod through a seed crystal shaft or a second steel wire.