Silicon nitride coating protection device for crystalline silicon ingot casting

Abstract

The utility model discloses a silicon nitride coating protection device for a crystalline silicon ingot casting, which comprises a graphite heat conduction seat, a rectangular crucible for the crystalline silicon ingot casting is arranged at the top of the graphite heat conduction seat, four graphite protection plates distributed in a rectangular shape are arranged at the top of the graphite heat conduction seat around the outer part of the rectangular crucible, and a cavity is formed among the four graphite protection plates; the rectangular crucible is arranged in the cavity and attached to the inner side wall of the graphite protection plate, and four blocking pieces are evenly arranged on the inner cavity wall of the rectangular crucible. According to the silicon nitride coating protection device disclosed by the invention, the silicon nitride coating on the inner wall of the rectangular crucible can be shielded, so that high-flow argon flow is prevented from impacting molten silicon in the rectangular crucible to shake, and the situation that the silicon nitride coating falls off due to the fact that the high-flow argon flow and the liquid level of the molten silicon shake and scour the silicon nitride coating is avoided; and the trouble of demolding damage caused by adhesion of the crystal silicon ingot and the rectangular crucible due to falling of the silicon nitride coating is also avoided, and the quality of the crystal silicon ingot is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of crystalline silicon ingot equipment, in particular to a silicon nitride coating protection device for crystalline silicon ingots. Background Art

[0002] Crystalline silicon ingot casting is an important link in the silicon material manufacturing process. It involves melting the silicon raw material and then directionally solidifying it under specific process conditions to form a silicon block with a specific crystal structure. Crystalline silicon ingot demolding is an important step in the crystalline silicon production process. It involves the process of smoothly separating the solidified crystal silicon ingot from the ingot casting equipment. It is achieved by providing a silicon nitride coating on the inner wall of the crucible to isolate the silicon material from the inner wall of the crucible, prevent the silicon material from direct contact with the crucible and adhesion, avoid damage to the surface of the crystal silicon ingot, destruction of the lattice structure or introduction of impurities, and ensure the quality of the crystal silicon ingot.

[0003] However, since oxygen and carbon are the main impurity elements in silicon ingots, oxygen and carbon will have adverse effects on subsequent silicon wafer processing and the photoelectric conversion efficiency of its silicon wafer application. Most of the existing methods for reducing the oxygen and carbon content in the ingot furnace are to reduce the air pressure in the ingot furnace, increase the flow rate of argon, an inert protective gas in the furnace, increase the gas flow rate in the furnace, and discharge the oxygen and carbon volatile gases. However, using this method to discharge the oxygen and carbon volatile gases will cause the large flow of argon in the furnace to continuously impact the solid-liquid-gas three-phase contact point composed of the quartz crucible, argon, and molten silicon surface, increase the degree of liquid surface shaking, weaken the adhesion effect of the silicon nitride coating and cause it to fall off, thereby causing the crystalline silicon ingot to stick abnormally to the crucible when demolding, affecting the quality of the crystalline silicon ingot. Therefore, those skilled in the art provide a silicon nitride coating protective device for crystalline silicon ingots to solve the problems raised in the above background technology. Utility Model Content

[0004] The purpose of the present invention is to provide a silicon nitride coating protection device for crystalline silicon ingots to solve the problems raised in the above background technology.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A silicon nitride coating protective device for crystalline silicon ingots, comprising: a graphite heat-conducting seat, a rectangular crucible for crystalline silicon ingots arranged on the top of the graphite heat-conducting seat, four graphite guard plates arranged in a rectangular shape around the top of the graphite heat-conducting seat and surrounding the outside of the rectangular crucible, a cavity being provided between the four graphite guard plates, the rectangular crucible being provided inside the cavity and being attached to the inner sidewall of the graphite guard plate, and four baffles being evenly provided on the inner cavity wall of the rectangular crucible, each of the four baffles being composed of a plurality of segmented pieces arranged in an interlaced manner, and a corner piece being provided between two adjacent baffles The two ends of the corner piece are respectively staggered with the segmented pieces on both sides, and the top side walls of the segmented pieces and the corner pieces are clamped and installed with L-shaped pull rods. One end of the L-shaped pull rod away from the segmented piece and the corner piece is clamped and installed on one side of the rectangular crucible and inserted into the inside of the graphite guard plate. A threaded column is provided at one end of the L-shaped pull rod inserted into the inside of the graphite guard plate. The threaded column passes through the graphite guard plate and extends to the outside thereof, and a fixing nut is provided at one end of the threaded column located outside the graphite guard plate. The fixing nut is threadedly installed on the outer wall of the threaded column and fits against the side wall of the graphite guard plate.

[0007] Preferably, the top side walls of the segmented piece and the corner piece are respectively provided with a first rectangular through hole and a second rectangular through hole, and a rectangular hook is provided at the bottom of the L-shaped pull rod. The L-shaped pull rod is engaged with the top of the segmented piece and the corner piece through the cooperation of the rectangular hook with the first rectangular through hole and the second rectangular through hole.

[0008] Preferably, a slot is provided on the inner side of the L-shaped pull rod, and the L-shaped pull rod is engaged with the side wall of the rectangular crucible through the slot.

[0009] Preferably, a portion of the side wall of the graphite guard plate above the rectangular crucible is evenly provided with a plurality of rectangular insertion holes, and one end of the L-shaped pull rod away from the segmented piece and the corner piece is inserted into the rectangular insertion hole.

[0010] Preferably, the end surface of the threaded column is smaller than the opening area of ​​the rectangular insertion hole, and the threaded column passes through the rectangular insertion hole and extends to the outside of the graphite guard plate.

[0011] Preferably, the end surface area of ​​the fixing nut is larger than the opening area of ​​the rectangular insertion hole, and the fixing nut covers the outside of the opening of the rectangular insertion hole and is tightly attached to the side wall of the graphite guard plate.

[0012] Preferably, the material of the baffle is silicon nitride ceramic, and the material of the L-shaped pull rod is carbon-carbon composite material.

[0013] Compared with the prior art, the advantages of the present invention are:

[0014] By setting a baffle, the baffle can be fixed to the inner wall of the rectangular crucible through an L-shaped pull rod, and the baffle is used to block the silicon nitride coating on the inner wall of the rectangular crucible to prevent a large flow of argon gas from impacting the molten silicon in the rectangular crucible and causing it to shake. This not only avoids the silicon nitride coating from falling off due to the large flow of argon gas and the shaking of the molten silicon liquid level, but also avoids the trouble of the silicon ingot sticking to the rectangular crucible due to the falling of the silicon nitride coating, which leads to its demolding damage. This ensures the demolding effect of the silicon nitride coating and improves the quality of the silicon ingot. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of a silicon nitride coating protection device according to an embodiment of the present invention;

[0016] Figure 2 Schematic diagram of a three-dimensional graphite heat conducting seat according to an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the connection of two baffles according to an embodiment of the present invention;

[0018] Figure 4 This is a three-dimensional schematic diagram of a rectangular hook according to an embodiment of the present utility model;

[0019] Figure 5 This is a schematic diagram of the connection between the rectangular hook and the graphite guard plate according to one embodiment of the present utility model;

[0020] Figure 6 Schematic diagram of the connection between the baffle and the graphite guard plate according to one embodiment of the present invention.

[0021] In the figure: 1. Graphite heat-conducting seat; 11. Graphite guard plate; 111. Cavity; 112. Rectangular jack; 12. Rectangular crucible; 2. Baffle; 21. Segmented piece; 211. First rectangular through hole; 22. Corner piece; 221. Second rectangular through hole; 3. L-shaped pull rod; 301. Slot; 31. Rectangular hook; 32. Threaded column; 33. Fixing nut. DETAILED DESCRIPTION

[0022] In the description of the present invention, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In addition, the term "including" and any variations thereof are intended to cover non-exclusive inclusions.

[0023] Combine Figures 1-6 As shown, a rectangular crucible 12 for crystalline silicon ingots is provided on the top of the graphite heat-conducting seat 1, and four graphite guard plates 11 distributed in a rectangular shape are provided on the top of the graphite heat-conducting seat 1 around the outside of the rectangular crucible 12. There is a cavity 111 between the four graphite guard plates 11, and the rectangular crucible 12 is arranged inside the cavity 111 and fits on the inner wall of the graphite guard plate 11. In addition, four baffles 2 are evenly provided on the inner wall of the rectangular crucible 12. The four baffles 2 are composed of a plurality of segmented sheets 21 arranged in a staggered manner, and a corner sheet 22 is provided between two adjacent baffles 2. The two ends of the corner sheet 22 are respectively connected to the segmented sheets on both sides. The sheets 21 are arranged in an staggered manner, and the top side walls of the segmented sheets 21 and the corner sheets 22 are both snap-fitted with L-shaped pull rods 3. One end of the L-shaped pull rod 3 away from the segmented sheets 21 and the corner sheets 22 is snap-fitted on one side of the rectangular crucible 12 and inserted into the interior of the graphite guard plate 11. A threaded column 32 is provided at one end of the L-shaped pull rod 3 inserted into the interior of the graphite guard plate 11. The threaded column 32 passes through the graphite guard plate 11 and extends to the outside thereof, and a fixing nut 33 is provided at one end of the threaded column 32 located outside the graphite guard plate 11. The fixing nut 33 is threadedly installed on the outer wall of the threaded column 32 and fits against the side wall of the graphite guard plate 11.

[0024] In one embodiment, when installing the baffle 2, each L-shaped pull rod 3 can be mounted on the first rectangular through hole 211 on the side wall of the segmented piece 21 through the rectangular hook 31, and then one end of the L-shaped pull rod 3 is inserted into the rectangular insertion hole 112 on the side wall of the graphite guard plate 11, so that the L-shaped pull rod 3 is engaged with one side of the rectangular crucible 12 through the card slot 301, and the segmented piece 21 is fixed to the inner wall of the rectangular crucible 12 to complete the installation of the segmented piece 21, and then the above steps are repeated to fix the other segmented pieces 21 on the inner wall of the rectangular crucible 12 and arrange them in a staggered manner. The baffle 2 is composed of the staggered segmented pieces 21, and then the L-shaped pull rod 3 is mounted on the corner piece 2 through the rectangular hook 31. 2, and then insert one end of the L-shaped pull rod 3 into the rectangular socket 112 on the side wall of the graphite guard plate 11 to complete the installation of the corner piece 22. Finally, repeat the above steps, connect the four baffles 2 through the corner piece 22, and let the four baffles 2 form a rectangular frame to block one side of the silicon nitride coating on the inner side of the rectangular crucible 12. The installation of the baffle 2 can be completed. The silicon nitride coating on the inner wall of the rectangular crucible 12 can be blocked by the baffle 2 to prevent the large flow of argon gas from impacting the molten silicon in the rectangular crucible 12 and causing it to shake, thereby avoiding the situation where the silicon nitride coating is washed away by the large flow of argon gas and the shaking of the molten silicon liquid level and causing it to fall off, thereby ensuring the use of the silicon nitride coating.

[0025] In one embodiment, when installing the L-shaped pull rod 3, one end of the L-shaped pull rod 3 can be inserted into the rectangular socket 112 on the side wall of the graphite guard plate 11, and the threaded column 32 installed on the L-shaped pull rod 3 is extended from the rectangular socket 112 to the outside of the graphite guard plate 11, and then the fixing nut 33 is screwed and installed on the outer wall of the threaded column 32 and tightly attached to the outer wall of the graphite guard plate 11, and the L-shaped pull rod 3 is tightened to limit the position of the L-shaped pull rod 3 to prevent the L-shaped pull rod 3 from being stuck in the graphite guard plate 11. The ink guard plate 11 shakes, which avoids the shaking of the segmented piece 21 and the baffle 2 connected thereto in the rectangular crucible 12 due to the shaking of the L-shaped pull rod 3, improves the stability of the baffle 2 and the segmented piece 21, and ensures the use of the baffle 2 and the segmented piece 21. In addition, the baffle 2 made of silicon nitride ceramic is in contact with the molten silicon, and the baffle 2 will not adhere to the molten silicon, avoiding the situation that the quality of the crystalline silicon ingot is affected by the adhesion of the baffle 2 to the molten silicon, and further improves the quality of the crystalline silicon ingot.

[0026] In one embodiment, since the rectangular hook 31, the first rectangular through hole 211 and the second rectangular through hole 221 are all rectangular, when the rectangular hook 31 is installed in the first rectangular through hole 211 and the second rectangular through hole 221, the rectangular hook 31 will not swing in the first rectangular through hole 211 and the second rectangular through hole 221, thereby avoiding the shaking of the segmented piece 21 and the corner piece 22 installed on the L-shaped pull rod 3 due to the shaking of the rectangular hook 31 in the first rectangular through hole 211 and the second rectangular through hole 221, thereby ensuring the stability of the segmented piece 21 and the corner piece 22, and the L-shaped pull rod 3 made of carbon-carbon composite material fixes the baffle 2, so that the L-shaped pull rod 3 will not be affected by the high temperature in the ingot furnace and deformed, thereby avoiding the trouble of the position displacement of the baffle 2 caused by the deformation of the L-shaped pull rod 3 due to the high temperature in the ingot furnace, thereby further improving the stability of the baffle 2.

[0027] In one embodiment, after long-term use, the fixing nut 33 can be screwed and removed, and then the L-shaped pull rod 3 can be pulled out from the rectangular socket 112 to complete the disassembly of each segmented piece 21 and the corner piece 22. The damaged segmented piece 21 or corner piece 22 can be replaced separately, avoiding the trouble of replacing the entire baffle 2 and facilitating subsequent maintenance work.

[0028] The working principle of the present invention is as follows: when producing crystalline silicon ingots, the baffle 2 can be fixed to the inner wall of the rectangular crucible 12 by the L-shaped pull rod 3, and the baffle 2 can block the silicon nitride coating on the inner wall of the rectangular crucible 12 to prevent the large-flow argon gas flow from impacting the molten silicon in the rectangular crucible 12 and causing it to shake. This not only avoids the situation where the silicon nitride coating is washed away by the large-flow argon gas flow and the shaking of the molten silicon liquid level and causes it to fall off, but also avoids the trouble of the crystalline silicon ingot being stuck to the rectangular crucible 12 due to the falling off of the silicon nitride coating, which causes its demolding to be damaged, thereby ensuring the demolding effect of the silicon nitride coating and improving the quality of the crystalline silicon ingot.

[0029] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A silicon nitride coating protective device for crystalline silicon ingots, comprising: A graphite heat-conducting seat (1), wherein a rectangular crucible (12) for crystalline silicon ingots is provided on the top of the graphite heat-conducting seat (1), characterized in that four graphite guard plates (11) distributed in a rectangular shape are provided on the top of the graphite heat-conducting seat (1) and surround the outside of the rectangular crucible (12), a cavity (111) is provided between the four graphite guard plates (11), the rectangular crucible (12) is provided inside the cavity (111) and is attached to the inner wall of the graphite guard plate (11), and the inner cavity wall of the rectangular crucible (12) is evenly provided with four baffles (2), each of the four baffles (2) is composed of a plurality of segmented pieces (21) arranged in an alternating manner, and a corner piece (22) is provided between two adjacent baffles (2), and the two ends of the corner piece (22) are respectively connected to the segmented pieces on both sides. The segments (21) are arranged in an interlaced manner, and the top side walls of the segmented segments (21) and the corner segments (22) are both snap-fitted with L-shaped pull rods (3), and one end of the L-shaped pull rod (3) away from the segmented segments (21) and the corner segments (22) is snap-fitted with one side of the rectangular crucible (12) and inserted into the interior of the graphite guard plate (11). The end of the L-shaped pull rod (3) inserted into the interior of the graphite guard plate (11) is provided with a threaded column (32), and the threaded column (32) passes through the graphite guard plate (11) and extends to the outside thereof, and the end of the threaded column (32) located outside the graphite guard plate (11) is provided with a fixing nut (33), and the fixing nut (33) is threadedly installed on the outer wall of the threaded column (32) and fits against the side wall of the graphite guard plate (11).

2. The silicon nitride coating protective device for crystalline silicon ingots according to claim 1, characterized in that: The top side walls of the segmented piece (21) and the corner piece (22) are respectively provided with a first rectangular through hole (211) and a second rectangular through hole (221); the bottom of the L-shaped pull rod (3) is provided with a rectangular hook (31); the L-shaped pull rod (3) is engaged with the top of the segmented piece (21) and the corner piece (22) through the cooperation of the rectangular hook (31) and the first rectangular through hole (211) and the second rectangular through hole (221).

3. The silicon nitride coating protective device for crystalline silicon ingots according to claim 1, characterized in that: A clamping groove (301) is provided on the inner side of the L-shaped pull rod (3), and the L-shaped pull rod (3) is clamped on the side wall of the rectangular crucible (12) through the clamping groove (301).

4. The silicon nitride coating protective device for crystalline silicon ingots according to claim 2, characterized in that: The side wall of the graphite guard plate (11) located above the rectangular crucible (12) is evenly provided with a plurality of rectangular insertion holes (112), and one end of the L-shaped pull rod (3) away from the segmented piece (21) and the corner piece (22) is inserted into the inside of the rectangular insertion hole (112).

5. The silicon nitride coating protective device for crystalline silicon ingots according to claim 4, characterized in that: The end surface of the threaded column (32) is smaller than the opening area of ​​the rectangular insertion hole (112), and the threaded column (32) passes through the rectangular insertion hole (112) and extends to the outside of the graphite guard plate (11).

6. The silicon nitride coating protective device for crystalline silicon ingots according to claim 4, characterized in that: The end surface area of ​​the fixing nut (33) is larger than the opening area of ​​the rectangular insertion hole (112), and the fixing nut (33) covers the outside of the opening of the rectangular insertion hole (112) and is tightly attached to the side wall of the graphite guard plate (11).

7. The silicon nitride coating protective device for crystalline silicon ingots according to claim 1, characterized in that: The material of the baffle (2) is silicon nitride ceramics, and the material of the L-shaped pull rod (3) is a carbon-carbon composite material.

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