Crucible assembly and crystal growth furnace
By designing a spacer in the crucible assembly, separating the gas volatile region from the crystal pulling region, the problem of oxygen impurities entering the crystal rod in single crystal silicon production is solved, and the oxygen impurity content of silicon rods is reduced and quality improvement is achieved.
Patent Information
- Application Number
- CN202420739174.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-11
- Publication Date
- 2025-01-14
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
During the production process of single crystal silicon, oxygen atoms generated by SiO reaction in the quartz crucible will enter the crystal rod, resulting in high oxygen content at the head of the crystal rod, affecting the quality of the crystal rod.
A crucible assembly is designed, including a crucible body and a spacer. The spacer is composed of a barrier wall and a fixed wall. The barrier wall separates the inner part of the crucible body into a gas volatile area and a crystal pulling area, and oxygen impurities volatilize and escape from the upper part of the gas volatile area. , reduce the oxygen content in the silicon melt.
The oxygen impurity content of the silicon rod is effectively reduced and the quality of the crystal rod is improved. Through the design of the spacer, the oxygen impurity content in the silicon melt is greatly reduced, and the oxygen impurity content of the silicon rod formed is reduced and the quality is higher.
Smart Images
Figure CN222349180U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of crystal growth equipment, and in particular to a crucible assembly and a crystal growth furnace. Background Art
[0002] The production of single crystal silicon in the photovoltaic industry generally adopts the direct pulling method. During the single crystal growth process, the seed crystal is immersed in the silicon melt in the quartz crucible using a pulling mechanism and a seed crystal chuck, and the seed crystal is slowly pulled upward using the pulling mechanism. In this way, a single crystal silicon rod of a certain diameter is grown under the seed crystal.
[0003] The main source of oxygen in single crystal silicon produced by the Czochralski method is SiO produced by the reaction between SiO in the quartz crucible and silicon raw materials. Under high temperature conditions, oxygen atoms in SiO at the solid-liquid interface will enter the crystal rod due to segregation, especially in the initial stage of crystal pulling, resulting in a high oxygen content in the head area of the crystal rod and reduced quality of the crystal rod. Utility Model Content
[0004] In view of this, the present application provides a crucible assembly and a crystal growth furnace, aiming to solve one of the technical problems in the prior art.
[0005] To achieve the above objectives, the technical solutions adopted in this application are as follows:
[0006] In a first aspect, an embodiment of the present application provides a crucible assembly, comprising:
[0007] A crucible body, comprising a side wall and a bottom wall;
[0008] The isolating member comprises a fixed wall and a blocking wall, wherein the fixed wall is connected to the crucible body and the blocking wall, the blocking wall is arranged in the crucible body and spaced apart from the side wall, the blocking wall separates the inside of the crucible body into a gas volatilization area and a crystal pulling area, and a first connecting structure is provided at one end of the blocking wall close to the bottom wall, and the first connecting structure connects the gas volatilization area and the crystal pulling area.
[0009] In one embodiment of the first aspect, a cross section of the barrier wall is a closed line pattern, and the barrier wall and the side wall are arranged in parallel.
[0010] In one embodiment of the first aspect, one end of the blocking wall away from the bottom wall is flush with one end of the side wall away from the bottom wall, and one end of the blocking wall close to the bottom wall is spaced apart from the bottom wall to define the first connecting structure.
[0011] In one embodiment of the first aspect, the fixed wall is arranged corresponding to the gas volatilization area, and a second connecting structure is provided on the fixed wall, and the second connecting structure connects the gas volatilization area with the outside.
[0012] In one embodiment of the first aspect, the fixed wall includes a plurality of connection portions, the plurality of connection portions are evenly spaced and distributed in a circular shape, and a gap between two adjacent connection portions forms the second connecting structure.
[0013] In one of the embodiments of the first aspect, the connecting portion connects an end of the blocking wall away from the bottom wall and an end of the side wall away from the bottom wall, and the connecting portion and the side wall are detachably connected.
[0014] In one of the embodiments of the first aspect, the fixed wall further includes a limiting portion, the side wall is provided with a groove corresponding to the limiting portion, and the limiting portion is engaged with the groove.
[0015] In one of the embodiments of the first aspect, in a length direction perpendicular to the side wall, the side wall enclosure distance is D1, and the distance between the barrier wall and the side wall is D2, satisfying: 0.1≤D2 / D1≤0.3.
[0016] In one embodiment of the first aspect, the barrier wall is made of silicon nitride material or a silicon nitride coating is provided on the surface of the barrier wall.
[0017] In a second aspect, an embodiment of the present application further provides a crystal growth furnace, comprising the crucible assembly in any of the above embodiments.
[0018] Compared with the prior art, the beneficial effects of the present application are as follows: the present application proposes a crucible assembly, comprising a crucible body and an isolating member, the crucible body comprising a side wall and a bottom wall, the isolating member comprising a fixed wall and a blocking wall, the fixed wall connecting the crucible body and the blocking wall, thereby connecting the isolating member to the crucible body; specifically, the blocking wall is arranged in the crucible body and spaced apart from the side wall, the blocking wall separates the inside of the crucible body into a gas volatilization area and a crystal pulling area, so that when the side wall is heated, SiO generated between the side wall of the crucible body and the silicon melt volatilizes and escapes from the silicon melt from the upper part of the gas volatilization area, and the content of oxygen impurities in the silicon melt at the bottom of the gas volatilization area is greatly reduced; the barrier wall is provided with a first connecting structure at one end close to the bottom wall, the first connecting structure connecting the gas volatilization area and the crystal pulling area, so that the silicon melt with less oxygen impurities enters the crystal pulling area for crystal pulling operation, and the oxygen impurity content of the formed silicon rod is reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0020] Figure 1 One of the structural schematic diagrams of the crucible assembly in some embodiments of the present application is shown;
[0021] Figure 2 The second structural schematic diagram of the crucible assembly in some embodiments of the present application is shown;
[0022] Figure 3 A schematic diagram of the structure of the isolation element in some embodiments of the present application is shown.
[0023] Explanation of the main component symbols: 100-crucible assembly; 110-crucible body; 111-side wall; 112-bottom wall; 120-isolating member; 121-blocking wall; 122-fixed wall; 1211-first connecting structure; 1221-connecting part; 1222-second connecting structure; 1223-limiting part; 113-gas volatilization area; 114-crystal pulling area. DETAILED DESCRIPTION
[0024] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0025] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" 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 application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0027] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0028] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0029] Usually, the crystal pulling process is to put the crystal raw material into the crucible assembly, and heat the side wall of the crucible body through the high temperature generated by the heater to melt the crystal raw material. Then, the molten silicon liquid is slightly cooled to produce a certain degree of supercooling, and then a silicon single crystal (called a seed crystal) fixed on the seed crystal axis is inserted into the melt surface. After the seed crystal and the melt are melted, the seed crystal is slowly pulled upward, and the crystal will grow into a crystal rod at the lower end of the seed crystal.
[0030] As mentioned above, in the absence of a spacer, the side wall of the crucible body and the silicon melt at the connection point under high temperature conditions are prone to react to produce SiO, which will sublime and volatilize the silicon melt at high temperature, causing SiO to rise in the silicon melt and gather on the surface of the silicon melt. At the same time, SiO in the silicon melt penetrates into the middle of the silicon melt along the radial direction of the side wall 111 under the action of thermal convection and segregation. Therefore, in the initial stage of crystal pulling, the oxygen content in the head area of the crystal rod is relatively high, and the quality of the crystal rod is reduced.
[0031] In response to the above problems, Figure 1As shown, the embodiment of the present application provides a crucible assembly 100, including a crucible body 110 and an isolating member 120, and the isolating member 120 is used in conjunction with the crucible body 110. Specifically, the isolating member 120 is used to block SiO from penetrating into the interior of the silicon melt from the edge of the silicon melt, so that the oxygen impurity content in the produced crystal rod is reduced and the quality of the crystal rod is improved.
[0032] The crucible body 110 includes a side wall 111 and a bottom wall 112. It is understood that the side wall 111 is generally an enclosed structure, such as a cylinder, a truncated cone or a rectangle, and the bottom wall 112 is connected to the bottom end of the side wall 111 to form the crucible body 110, which is used to contain silicon melt.
[0033] The isolation member 120 includes a fixed wall 122 and a barrier wall 121. The fixed wall 122 connects the crucible body 110 and the barrier wall 121, thereby connecting the isolation member 120 to the crucible body 110. Specifically, the barrier wall 121 is disposed in the crucible body 110 and spaced apart from the side wall 111. The barrier wall 121 separates the interior of the crucible body 110 into a gas volatilization area 113 and a crystal pulling area 114.
[0034] Thus, when the side wall 111 is heated, SiO generated between the side wall 111 of the crucible body 110 and the silicon melt is gathered in the gas volatilization region 113 under the action of the barrier wall 121, and does not directly enter the crystal pulling region 114. The SiO in the gas volatilization region 113 moves upward and volatilizes from the upper part of the gas volatilization region 113 to escape from the silicon melt, so that the content of SiO in the silicon melt at the bottom of the gas volatilization region 113 is greatly reduced.
[0035] The first connecting structure 1211 is provided at one end of the barrier wall 121 close to the bottom wall 112, and the first connecting structure 1211 connects the gas volatilization area 113 and the crystal pulling area 114. In this way, the silicon melt with less SiO at the bottom of the gas volatilization area 113 enters the crystal pulling area 114 from the first connecting structure 1211 for crystal pulling operation, and the silicon rod formed has a lower oxygen impurity content and a higher quality.
[0036] In one embodiment, the cross section of the barrier wall 121 is a closed line pattern, and the barrier wall 121 is arranged in parallel with the side wall 111. In this way, the barrier wall 121 and the side wall 111 components form a structure that is connected up and down, and the silicon melt in the gas volatilization area 113 cannot flow along the radial direction of the side wall 111, and can only flow into the crystal pulling area 114 from the first connecting structure 1211 below the barrier wall 121, thereby increasing the flow distance of the silicon melt in the gas volatilization area 113, prolonging the flow time, and allowing SiO in the silicon melt to fully volatilize.
[0037] Preferably, the shape of the barrier wall 121 is the same as that of the side wall 111, and the barrier wall 121 is cylindrical, truncated cone or rectangular. In this way, the gas volatilization area 113 is annular and has the same thickness everywhere, and the pulled crystal rod is more uniform. Of course, the shape of the barrier wall 121 can also be designed according to actual needs, and there is no special limitation.
[0038] The end of the blocking wall 121 away from the bottom wall 112 is flush with the end of the side wall 111 away from the bottom wall 112, making the overall structure of the crucible assembly 100 more beautiful, and can also increase the depth of the silicon melt in the crucible body 110, thereby improving the crystal rod yield of a single crystal pulling.
[0039] It can be understood that by controlling the depth of the first connecting structure 1211 and making the first connecting structure 1211 close to the bottom wall 112 of the crucible body 110, the SiO content of the silicon melt in the crystal pulling area 114 can be reduced. By controlling the size of the first connecting structure 1211, the flow rate of the silicon melt between the gas volatilization area 113 and the crystal pulling area 114 can be adjusted.
[0040] In some embodiments, one end of the barrier wall 121 close to the bottom wall 112 can be connected to the bottom wall 112, and an annular through hole is opened at the end of the barrier wall 121 close to the bottom wall 112. The annular through hole is the first connecting structure 1211, which allows the silicon melt in the lower part of the gas volatilization area 113 to enter the crystal pulling area 114.
[0041] Preferably, in the present embodiment, one end of the barrier wall 121 close to the bottom wall 112 is spaced apart from the bottom wall 112 to define a first connecting structure 1211. This simplifies the processing technology of the barrier wall 121 and increases the flux of the silicon melt between the gas volatilization area 113 and the crystal pulling area 114.
[0042] Specifically, in the length direction of the side wall 111 , the length of the crucible body 110 is H1 , and the length of the barrier wall 121 is H2 , satisfying: 0.6≤H2 / H1≤0.8.
[0043] In this embodiment, H2 / H1 is 0.7, and in other embodiments, H2 / H1 may also be 0.6, 0.65, 0.75, 0.8, etc., which is not limited to the ratios shown in the examples. In this way, the silicon melt stays in the gas volatilization area 113 for a long enough time to fully volatilize the SiO therein, and the silicon melt at the bottom can quickly enter the crystal pulling area 114 from the gas volatilization area 113 to avoid affecting the crystal pulling efficiency.
[0044] In one embodiment, the fixed wall 122 is arranged corresponding to the gas volatilization area 113, and a second connecting structure 1222 is arranged on the fixed wall 122, and the second connecting structure 1222 connects the gas volatilization area 113 with the outside. In this way, SiO in the silicon melt in the gas volatilization area 113 is volatilized, and other impurity gases and volatiles in the molten silicon can be discharged, thereby improving the quality of the silicon rod.
[0045] Illustratively, in this embodiment, the fixed wall 122 includes a plurality of connection portions 1221 , and the plurality of connection portions 1221 are evenly spaced and distributed in a circular shape, and a gap between two adjacent connection portions 1221 forms a second connecting structure 1222 .
[0046] like Figure 3 As shown, each connecting portion 1221 is fan-shaped, and multiple fan-shaped portions are evenly spaced apart, with one arc edge of each fan-shaped portion connected to the blocking wall 121, and the other arc edge connected to the side wall 111. The two fan-shaped portions are spaced apart, and SiO in the silicon melt escapes from the gap between the two fan-shaped portions after volatilization.
[0047] In other embodiments, the connecting portion 1221 is in a strip shape and extends radially along the side wall 111 , and two adjacent strips are spaced apart to form the second connecting structure 1222 . A plurality of through holes may also be opened on the annular plate-shaped connecting portion 1221 to form the second connecting structure 1222 .
[0048] In one embodiment, the connection portion 1221 connects one end of the barrier wall 121 away from the bottom wall 112 and one end of the side wall 111 away from the bottom wall 112 . The connection portion 1221 and the side wall 111 are detachably connected, so that the isolation member 120 can be used multiple times.
[0049] Specifically, Figure 1 As shown, the fixed wall 122 further includes a limiting portion 1223, and the side wall 111 is provided with a groove corresponding to the limiting portion 1223, and the limiting portion 1223 is engaged with the groove. In this way, the isolation member 120 can be prevented from falling off from the crucible body 110, and the isolation member 120 can also be prevented from rotating.
[0050] In one embodiment, Figure 2 As shown, in the length direction perpendicular to the side wall 111 , the enclosed distance of the side wall 111 is D1 , and the distance between the blocking wall 121 and the side wall 111 is D2 , satisfying: 0.1≤D2 / D1≤0.3.
[0051] In this embodiment, D2 / D1 is 0.2. In other embodiments, D2 / D1 may be 0.1, 0.15, 0.25, 0.3, etc., without limiting the ratio of the examples.
[0052] In this way, a sufficiently large area is reserved for the crystal pulling operation without affecting the crystal pulling efficiency. At the same time, SiO in the silicon melt can be removed through the gas volatilization area 113 to improve the quality of the silicon rod.
[0053] In this embodiment, the barrier wall 121, the connection part 1221 and the stopper 1223 are made of silicon nitride material or the surfaces of the barrier wall 121, the connection part 1221 and the stopper 1223 are provided with silicon nitride coating. In this way, it is possible to prevent the reaction between the silicon melt and the barrier wall 121 to produce SiO. In other embodiments, graphite or silicon carbide material can be used instead of silicon nitride material. Although it can also prevent the reaction between the silicon melt and the barrier wall 121 to produce SiO, it is easy to produce carbon oxides that enter the silicon melt and reduce the quality of the crystal rod.
[0054] It should be noted that, whether it is graphite, silicon carbide material, silicon nitride material or silicon carbide combined with silicon nitride material, their thermal reaction temperatures are higher than silicon dioxide (i.e., the melting point of the crucible body 110 is above 1700°C). In this way, during the crystal growth process, i.e., at a high temperature of 1200°C to 1400°C, since the thermal reaction temperature of the barrier wall 121 material is not reached, the isolation member 120 will not react with the crucible body 110, thereby extending the service life of the crucible assembly 100. At the same time, in addition to the above advantages, silicon nitride material is a bonding material and has many advantages such as energy saving, environmental protection, high temperature resistance, and corrosion resistance.
[0055] The embodiment of the present application further provides a crystal growth furnace, including the crucible assembly 100 in any of the above embodiments, and thus has all the beneficial effects of the crucible assembly 100 in any of the above embodiments, which will not be described in detail here.
[0056] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0057] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.
Claims
1. A crucible assembly, characterized in that: include: A crucible body, including a side wall and a bottom wall; The isolating member comprises a fixed wall and a blocking wall, wherein the fixed wall is connected to the crucible body and the blocking wall, the blocking wall is arranged in the crucible body and spaced apart from the side wall, the blocking wall separates the inside of the crucible body into a gas volatilization area and a crystal pulling area, and a first connecting structure is provided at one end of the blocking wall close to the bottom wall, and the first connecting structure connects the gas volatilization area and the crystal pulling area.
2. The crucible assembly according to claim 1, characterized in that: The cross section of the barrier wall is a closed line pattern, and the barrier wall and the side wall are arranged in parallel.
3. The crucible assembly according to claim 1, characterized in that: One end of the blocking wall away from the bottom wall is flush with one end of the side wall away from the bottom wall, and one end of the blocking wall close to the bottom wall is spaced apart from the bottom wall to define and form the first connecting structure.
4. The crucible assembly according to claim 1, characterized in that: The fixed wall is arranged corresponding to the gas volatilization area, and a second connecting structure is arranged on the fixed wall, and the second connecting structure connects the gas volatilization area with the outside.
5. The crucible assembly according to claim 4, characterized in that: The fixed wall includes a plurality of connection parts, the plurality of connection parts are evenly spaced and distributed in a circular shape, and a gap between two adjacent connection parts forms the second connecting structure.
6. The crucible assembly according to claim 5, characterized in that: The connecting portion connects one end of the blocking wall away from the bottom wall and one end of the side wall away from the bottom wall, and the connecting portion and the side wall are detachably connected.
7. The crucible assembly according to claim 6, characterized in that: The fixed wall further includes a limiting portion, the side wall is provided with a groove corresponding to the limiting portion, and the limiting portion is clamped in the groove.
8. The crucible assembly according to any one of claims 1 to 7, characterized in that: In the length direction perpendicular to the side wall, the side wall enclosure distance is D1, and the distance between the blocking wall and the side wall is D2, satisfying: 0.1≤D2 / D1≤0.
3.
9. The crucible assembly according to any one of claims 1 to 7, characterized in that: The barrier wall is made of silicon nitride material or a silicon nitride coating is provided on the surface of the barrier wall.
10. A crystal growth furnace, characterized in that: A crucible assembly comprising any one of claims 1 to 9.