Combined crucible for continuous crystal pulling

Abstract

The utility model discloses a combined crucible for continuous crystal pulling, which comprises a first crucible and a second crucible, the second crucible is arranged in the first crucible, the second crucible and the first crucible form a melt interlayer, and at least one first through hole is arranged on the side wall of the second crucible, so that the second crucible is communicated with the first crucible. According to the combined crucible for continuous crystal pulling disclosed by the utility model, the two crucible sleeves are adopted to form a communication structure, so that the problems of liquid level decline, low efficiency and great influence of granular silicon on silicon liquid in the second crucible in the existing crystal pulling process are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of crucibles, and more specifically, to a combined crucible for continuous single crystal pulling of single crystal silicon. Background Art

[0002] The current technologies for preparing single crystal silicon are mainly divided into two types: floating zone melting method and Czochralski method. The Czochralski method is relatively lower in cost, faster in growth rate, and more suitable for pulling large-size single crystal silicon rods. Currently, single crystal silicon is mainly produced by the Czochralski method. CZ is a common method for growing crystals from a melt, which requires the crystal to melt congruently. Its main advantage is that it is an intuitive technology that can grow large and dislocation-free single crystals in a short time.

[0003] Disadvantages: 1. Generally, a quartz crucible is used as a container, resulting in varying degrees of contamination of the melt; 2. When the melt contains volatile substances, it is difficult to control the components; 3. Whether it is the batch pulling method or the RCZ method, the silicon melt in the crucible will decrease as the single crystal silicon rod is pulled, causing the liquid level to drop, resulting in instability of the thermal dynamic environment in the pulling environment, and easily causing non-uniformity of the properties of the pulled single silicon crystal rod. As the growth process progresses, the liquid level in the crucible will continuously drop, and the inner wall of the crucible will be gradually exposed. Since the temperature of the crucible wall is very high, it has a great influence on the temperature field in the crystal and the melt, and even causes interface inversion. 4. When a pulled crystal cools in the gate, the silicon raw material for the next pull is added to the remaining silicon melt in the crucible through the feeding tube. Therefore, the addition of silicon material is completed when the crystal cools. However, before the next pull, it is necessary to wait for the single silicon crystal rod to cool down and be removed in the gate chamber, resulting in low efficiency in the industrial production of the RCZ method. Content of the Utility Model

[0004] In view of the above deficiencies in the current Czochralski method for producing single crystal silicon, the utility model provides a combined crucible for continuous single crystal pulling of single crystal silicon, which solves the problems of liquid level drop, temperature non-uniformity, and low efficiency by combining crucibles.

[0005] In order to achieve the above utility model purpose, the utility model adopts the following technical solutions:

[0006] A combined crucible for continuous single crystal pulling, including a first crucible and a second crucible. The second crucible is placed in the first crucible to form a molten material interlayer with the first crucible. At least one first through hole is provided on the side wall of the second crucible to make the second crucible communicate with the first crucible.

[0007] Further technical solution of the utility model:

[0008] Preferably, the number of the first through holes of the second crucible is an even number and is arranged oppositely.

[0009] Preferably, a mixer is arranged in the second crucible.

[0010] Preferably, the mixer has a cylindrical structure, with second through holes on its surface, and the port of the mixer is connected to the first through hole on the side wall of the second crucible.

[0011] Preferably, the first crucible includes a quartz outer crucible and a silicon nitride inner crucible embedded inside the quartz outer crucible, and the silicon nitride inner crucible is formed by splicing a plurality of plate-shaped first silicon nitride components.

[0012] Preferably, the second crucible includes one of an integral silicon nitride crucible and a combined silicon nitride crucible.

[0013] Preferably, the combined silicon nitride crucible includes:

[0014] Upper split body: formed by enclosing a plurality of plate-shaped second silicon nitride components through clamping parts;

[0015] Lower split body: having a card slot at the upper end;

[0016] The lower end of the upper split body is inserted into the card slot at the upper end of the lower split body, and the first through hole is arranged on the lower split body.

[0017] Preferably, an isolator is arranged between the first crucible and the second crucible.

[0018] Preferably, a plurality of third through holes are arranged on the surface of the isolator.

[0019] Preferably, the isolator includes one of a cylindrical shape and a horn shape.

[0020] The beneficial effects of the present utility model are:

[0021] (1) For the combined crucible for continuous crystal pulling of the present utility model, two crucibles are sleeved to form a communication structure, solving the problems of liquid level drop, low efficiency and great influence of granular silicon on the silicon liquid in the second crucible during the existing crystal pulling process.

[0022] (2) For the combined crucible for continuous crystal pulling of the present utility model, by arranging an isolator and a mixer, the problem of large temperature fluctuation of the silicon liquid in the second crucible is solved. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the combined crucible for continuous crystal pulling in Embodiment 1 disclosed by the present invention;

[0024] Figure 2 is a schematic structural diagram of the first crucible in Embodiment 1 disclosed by the present invention;

[0025] Figure 3 is a schematic structural diagram of the silicon nitride inner crucible in Embodiment 1 disclosed by the present invention;

[0026] Figure 4 Schematic diagram of the second crucible structure of Embodiment 1 disclosed in the present invention;

[0027] Figure 5 Schematic diagram of the lower split structure of the second crucible of Embodiment 1 disclosed in the present invention;

[0028] Figure 6 Schematic diagram of the second silicon nitride component structure of Embodiment 1 disclosed in the present invention;

[0029] Figure 7 Schematic diagram of the combined crucible structure for continuous crystal pulling of Embodiment 2 disclosed in the present invention;

[0030] Figure 8 Schematic diagram of the cylindrical isolator structure of Embodiment 2 disclosed in the present invention;

[0031] Figure 9 Schematic diagram of the combined crucible structure for continuous crystal pulling of Embodiment 3 disclosed in the present invention;

[0032] Figure 10 Schematic diagram of the horn-shaped isolator structure of Embodiment 3 disclosed in the present invention;

[0033] Figure 11 Schematic diagram of the combined crucible structure for continuous crystal pulling of Embodiment 4 disclosed in the present invention;

[0034] Figure 12 Schematic diagram of the mixer structure of Embodiment 4 disclosed in the present invention;

[0035] Description of the reference numerals in the schematic diagram:

[0036] 1. First crucible; 11. Quartz outer crucible; 12. Silicon nitride inner crucible; 121. First silicon nitride component; 2. Second crucible; 21. Upper split; 211. Second silicon nitride component; 212. Clamping member; 22. Lower split; 221. Card slot; 3. First through hole; 4. Mixer; 41. Second through hole; 5. Cylindrical isolator; 51. Third through hole; 6. Horn-shaped isolator. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be further described in detail below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part rather than all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0038] Embodiment 1: As Figures 1-6As shown in the figure, a combined crucible for continuous crystal pulling in this embodiment includes a first crucible 1 and a second crucible 2. The second crucible 2 is placed in the first crucible 1 to form a molten material interlayer with the first crucible 1. A first through hole 3 is provided on the side wall of the second crucible 2 to connect the second crucible 2 and the first crucible 1. Granular silicon is put into the molten material interlayer and enters the second crucible 2 after melting through the first through hole 3.

[0039] Monocrystalline silicon wafers are classified into 6-inch, 8-inch, 12-inch, 18-inch, etc. according to their diameters. The larger the diameter of the wafer, the higher the requirements for materials and technology. Existing monocrystalline silicon wafers are generally pulled using quartz crucibles, but quartz crucibles have a short service life, and quartz will react with silicon liquid, resulting in oxygen being incorporated into the silicon wafers. If silicon nitride material is used, the maximum diameter of the high-strength silicon nitride crucible prepared by the existing isostatic pressing method is about 12 inches, making it difficult to prepare large-size silicon wafers.

[0040] To obtain a large-size silicon nitride crucible, further, the first crucible 1 includes a silicon nitride inner crucible 12 and a quartz outer crucible 11. The silicon nitride inner crucible 12 is formed by splicing a plurality of plate-shaped first silicon nitride components 121. Due to the different thermal expansion coefficients of silicon nitride and quartz, at high temperatures, the quartz outer crucible 11 forms a compressive stress inward, causing the plate-shaped silicon nitride first components to be clamped tightly to form the silicon nitride inner crucible 12 with a diameter of 1000 mm.

[0041] The second crucible 2 is a combined silicon nitride crucible, including: an upper split body 21, which is formed by surrounding a plurality of plate-shaped second silicon nitride components 211 through a clamping member 212; a lower split body 22, which has a card slot 221 at the upper end. The lower end of the upper split body 21 is inserted into the card slot 221 at the upper end of the lower split body 22.

[0042] The use of a combined silicon nitride crucible solves the problems that it is difficult to prepare a larger size with the existing isostatic pressing method for high-strength silicon nitride crucibles and the high oxygen content in silicon wafers.

[0043] Example 2: As Figures 7-8 shown, on the basis of Example 1, a cylindrical isolator 5 is provided between the first crucible 1 and the second crucible 2, and the granular silicon is blocked between the first crucible 1 and the cylindrical isolator 5.

[0044] The distribution of granular silicon in the upper and lower parts of the molten material interlayer is uneven, and the temperature fluctuations in the upper and lower parts of the molten material interlayer are relatively large. The cylindrical isolator 5 effectively avoids affecting the temperature inside the second crucible 2.

[0045] A plurality of third through holes 51 are provided on the cylindrical isolator 5 for the molten granular silicon to pass through. The cylindrical isolator 5 and the first crucible 1 form a molten material interlayer. A first through hole 3 is provided on the side wall of the second crucible 2 to connect the second crucible 2 and the first crucible 1. Granular silicon is put into the molten material interlayer, melts and then passes through the third through holes 51 of the cylindrical isolator 5, and then enters the second crucible 2 through the first through hole 3.

[0046] Example 3: As Figures 9-10 shown, a horn-shaped isolator 6 is provided between the first crucible 1 and the second crucible 2, and the granular silicon is blocked between the first crucible 1 and the horn-shaped isolator 6. The horn-shaped isolator 6 only differs in shape from the cylindrical isolator 5 in Example 2.

[0047] Example 4, as Figures 11-12 shown, on the basis of Example 1, two opposite first through holes 3 are provided on the side wall of the second crucible 2, and a mixer 4 is arranged in the second crucible 2. The mixer 4 has a cylindrical structure, and second through holes 41 are provided on the surface. The ports at both ends of the mixer 4 are connected to the first through holes 3 on the side wall of the second crucible 2.

[0048] The granular silicon is put into the molten material interlayer, and after melting, it enters the mixer 4 through the first through hole 3. After the silicon liquid enters the mixer 4, it flows into the second crucible 2 through the second through holes 41 on the surface of the mixer 4.

[0049] In this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0050] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "arranged", "installed", "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0051] The above content is only an example and explanation of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as it does not deviate from the structure of the invention or exceed the scope defined by this claim book, it should fall within the protection scope of the present invention.

Claims

1. A combined crucible for continuous crystal pulling, characterized in that, It includes a first crucible and a second crucible. The second crucible is placed in the first crucible to form a molten material sandwich layer with the first crucible. At least one first through hole is provided on the side wall of the second crucible to make the second crucible communicate with the first crucible.

2. The combined crucible for continuous crystal pulling according to claim 1, characterized in that, The number of the first through holes of the second crucible is an even number and they are arranged oppositely.

3. The combined crucible for continuous crystal pulling according to claim 2, characterized in that, A mixer is arranged in the second crucible.

4. A combined crucible for continuous crystal pulling according to claim 3, characterized in that, The mixer has a cylindrical structure, and second through holes are provided on the surface. The port of the mixer is connected to the first through hole on the side wall of the second crucible.

5. The combined crucible for continuous crystal pulling according to claim 1, wherein The first crucible includes a quartz outer crucible and a silicon nitride inner crucible embedded inside the quartz outer crucible. The silicon nitride inner crucible is spliced by a plurality of plate-shaped first silicon nitride components.

6. The combined crucible for continuous crystal pulling according to claim 1, characterized in that The second crucible includes one of an integral silicon nitride crucible and a combined silicon nitride crucible.

7. A combined crucible for continuous crystal pulling according to claim 6, characterized in that, The combined silicon nitride crucible includes: Upper split body: It is formed by surrounding a plurality of plate-shaped second silicon nitride components through clamping parts; Lower split body: It has a clamping groove at the upper end; The lower end of the upper split body is inserted into the clamping groove at the upper end of the lower split body, and the first through hole is arranged on the lower split body.

8. A combined crucible for continuous crystal pulling according to claim 1, characterized in that An isolator is arranged between the first crucible and the second crucible.

9. The combined crucible for continuous crystal pulling according to claim 8, wherein, A plurality of third through holes are provided on the surface of the isolator.

10. A combined crucible for continuous crystal pulling according to claim 9, characterized in that, The isolator includes one of a cylindrical shape and a horn shape.

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