A crystal production apparatus

Abstract

The embodiment of the present specification provides a crystal preparation device for preparing a crystal by a liquid phase method, which comprises: a growth cavity, at least one layer of plate assemblies is arranged in the growth cavity, wherein the at least one layer of plate assemblies comprises through holes; the density of the through holes gradually decreases from the center to the edge of the plate assemblies; a heating assembly for heating the growth cavity; a connecting assembly for connecting a seed crystal holder to support a seed crystal; and a power assembly for driving the connecting assembly to rotate and / or move up and down, so as to drive the seed crystal holder to rotate and / or move up and down.

Description

[0001] Case Analysis

[0002] This application is a divisional application of Chinese application filed on June 7, 2022, with application number 202210632655.5 and entitled "A Crystal Preparation Apparatus". Technical Field

[0003] This specification relates to the field of crystal preparation technology, and in particular to an apparatus for preparing crystals based on a liquid-phase method. Background Technology

[0004] In the preparation of crystals (e.g., silicon carbide) based on liquid-phase methods (e.g., liquid-phase epitaxy, LPE), volatile components in the raw materials can rise or even evaporate into a gaseous state and continue to overflow into the external insulation components, causing excessive consumption of the raw materials. Furthermore, the evaporation process leads to component deviation in the raw materials, affecting crystal growth. In addition, the overflowing vapor can affect the insulation performance of the insulation components. Therefore, it is necessary to provide a crystal preparation apparatus that improves the movement of volatile components to further ensure normal crystal growth. Summary of the Invention

[0005] One embodiment of this specification provides a crystal preparation apparatus for liquid-phase crystal preparation. The apparatus includes: a growth chamber, wherein at least one plate assembly is disposed within the growth chamber, and the at least one plate assembly includes through holes; a heating assembly for heating the growth chamber; a connecting assembly for connecting a seed crystal holder to support the seed crystal; and a power assembly for driving the connecting assembly to rotate and / or move up and down, thereby driving the seed crystal holder to rotate and / or move up and down.

[0006] In some embodiments, the through-holes of adjacent plate assemblies are staggered.

[0007] In some embodiments, for at least one of the at least one plate assembly, the ratio of the total opening area of ​​the through holes to the upper surface area of ​​the plate assembly is in the range of 30%-80%.

[0008] In some embodiments, the density of the vias gradually decreases from the center to the edge of the plate assembly.

[0009] In some embodiments, the ratio of the via density near the center of the board assembly to the via density near the edge of the board assembly is in the range of 1:1 to 20:1.

[0010] In some embodiments, the diameter of the through hole is in the range of 0.1 mm to 10 mm.

[0011] In some embodiments, a coating is applied or a shielding ring is provided on the upper portion of the sidewall of the growth chamber within a predetermined range.

[0012] In some embodiments, the device further includes a cavity cover and an upper insulation component, wherein the gap between the cavity cover and the upper insulation component is filled with carbon powder.

[0013] In some embodiments, the cavity cover includes a raised structure.

[0014] In some embodiments, the wall thickness of the growth chamber sidewall gradually increases from the top to the bottom of the growth chamber. Attached Figure Description

[0015] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0016] Figure 1 This is a schematic diagram of the structure of an exemplary crystal preparation apparatus according to some embodiments of this specification;

[0017] Figure 2 This is a schematic diagram of through-holes on an exemplary board assembly according to some embodiments of this specification;

[0018] Figure 3 This is a schematic diagram of through-holes on an exemplary board assembly according to some embodiments of this specification;

[0019] Figure 4 This is a partial structural schematic diagram of an exemplary cavity cover and upper insulation component according to some embodiments of this specification;

[0020] Figure 5 This is a schematic diagram of the structure of an exemplary growth chamber shown in some embodiments of this specification;

[0021] Figure 6 This is a schematic diagram of the structure of an exemplary seed crystal holder and a seed crystal according to some embodiments of this specification;

[0022] Figure 7 This is a flowchart illustrating an exemplary crystal preparation method according to some embodiments of this specification.

[0023] In the figure, 100 is the crystal preparation device, 110 is the growth chamber, 120 is the heating component, 111 is the plate component, 1111 is the through hole, 130 is the chamber cover, 131 is the gap, 132 is the protruding structure, 140 is the heat preservation component, 141 is the upper heat preservation component, 142 is the middle heat preservation component, 143 is the bottom heat preservation component, 144 is the lower heat preservation component, 150 is the seed crystal holder, 160 is the connecting component, 170 is the cover plate, 180 is the seed crystal, 181 is the first seed crystal, 182 is the second seed crystal, and 190 is the graphite paper. Detailed Implementation

[0024] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0025] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0026] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0027] Figure 1 This is a schematic diagram of the structure of an exemplary crystal preparation apparatus according to some embodiments of this specification.

[0028] In some embodiments, the crystal preparation apparatus 100 can prepare crystals (e.g., silicon carbide) based on a liquid-phase method. The crystal preparation apparatus 100 described in detail below, with reference to the accompanying drawings and using the preparation of silicon carbide crystals as an example, will be explained in detail. It is worth noting that the following embodiments are merely illustrative of this specification and do not constitute a limitation of this application.

[0029] like Figure 1 As shown, the crystal preparation apparatus 100 may include a growth chamber 110 and a heating assembly 120.

[0030] The growth chamber 110 serves as the site for crystal preparation, and the heating assembly 120 is used to heat the growth chamber 110 to provide the heat (e.g., temperature, temperature field, etc.) required for crystal preparation.

[0031] In some embodiments, the material of the growth chamber 110 can be determined according to the type of crystal to be prepared. For example, when preparing silicon carbide crystals, the material of the growth chamber 110 may include graphite. In some embodiments, the material of the growth chamber 110 may also include molybdenum, tungsten, tantalum, etc. In some embodiments, the growth chamber 110 can provide the raw materials required for crystal preparation. For example, the growth chamber 110 can serve as a carbon source, providing the carbon required for preparing silicon carbide crystals. In some embodiments, the raw materials required for crystal preparation (e.g., silicon powder, carbon powder) can be placed inside the growth chamber 110. In some embodiments, the growth chamber 110 can be a place where the raw materials form a melt. For example, under the high temperature generated by the heating component 120, the silicon powder melts into a melt (liquid state), and the carbon provided by the growth chamber 110 itself dissolves in the silicon solution, forming a carbon solution in silicon, which serves as a liquid raw material for preparing silicon carbide crystals by the liquid phase method. In some embodiments, in order to improve the solubility of carbon in silicon, fluxes (e.g., aluminum, silicon-chromium alloys, Li-Si alloys, Ti-Si alloys, Fe-Si alloys, Sc-Si alloys, Co-Si alloys, etc.) can be added to the raw materials.

[0032] In some embodiments, a coating or a shielding ring may be applied to the upper predetermined area of ​​the inner wall of the growth chamber 110 to prevent the silicon near the melt surface from reacting with the carbon on the sidewall of the growth chamber 110 and spontaneously nucleating and crystallizing. In some embodiments, the coating or shielding ring may be made of a high-temperature resistant metal (e.g., rare earth metals such as tungsten, tantalum, molybdenum, and chromium, or aluminum) or a metal compound (e.g., zirconium oxide, aluminum oxide, etc.).

[0033] In some embodiments, the upper preset range may be 0-2 / 3 of the height along the growth chamber. In some embodiments, the upper preset range may be 0-1 / 3 of the height along the growth chamber. In some embodiments, the upper preset range may be 0-1 / 4 of the height along the growth chamber.

[0034] For further description of the growth chamber 110, please refer to other parts of this specification (e.g., Figure 5 (and its description), which will not be repeated here.

[0035] In some embodiments, the heating component 120 may include an induction heating component, a resistance heating component, etc. In some embodiments, the heating component 120 may be disposed around the outer periphery of the growth chamber 110.

[0036] In some embodiments, the heating assembly 120 may include an induction coil. In some embodiments, the induction coil may be disposed around the outer periphery of the growth chamber 110. In some embodiments, in order to ensure the temperature field required for crystal growth and improve crystal growth efficiency, the height ratio of the growth chamber 110 to the induction coil needs to be within a preset range.

[0037] In some embodiments, the height ratio of the growth cavity 110 to the induction coil can be in the range of 1:1 to 1:5. In some embodiments, the height ratio of the growth cavity 110 to the induction coil can be in the range of 1:1.5 to 1:4.5. In some embodiments, the height ratio of the growth cavity 110 to the induction coil can be in the range of 1:2 to 1:4. In some embodiments, the height ratio of the growth cavity 110 to the induction coil can be in the range of 1:2.5 to 1:3.5. In some embodiments, the height ratio of the growth cavity 110 to the induction coil can be in the range of 1:2.8 to 1:3.

[0038] In some embodiments, at least one plate assembly 111 may be disposed within the growth chamber 110. In some embodiments, the plate assembly 111 may be located within the melt inside the growth chamber 110.

[0039] During silicon carbide crystal growth, convection occurs in the melt within the growth chamber 110, causing silicon to move upwards from the bottom of the chamber and even evaporate from a liquid state to a gaseous state, continuing to rise and resulting in excessive silicon consumption. Furthermore, the overflowing silicon vapor may spill out of the growth chamber 110 and adhere to the insulation components outside the chamber, contaminating the insulation components and affecting their insulation performance. Accordingly, at least one plate assembly 111 disposed within the growth chamber can alter the convection of the melt, slowing the upward movement of silicon and preventing excessive consumption. Simultaneously, it avoids or reduces the amount of silicon vapor overflowing from the chamber, thus preventing or reducing contamination of the insulation components.

[0040] In some embodiments, the material of the plate assembly 111 can be determined according to the type of crystal to be prepared. For example, when preparing silicon carbide crystals, the material of the plate assembly 111 is the same as that of the growth chamber 110 (e.g., graphite). Graphite can serve as a carbon source, providing the carbon required for preparing silicon carbide crystals, and can also react with silicon to generate silicon carbide. Accordingly, the consumption of the growth chamber 110 can be reduced, and the number of times the growth chamber 110 can be used can be increased.

[0041] In some embodiments, the board assembly 111 may include through-holes. These through-holes can serve as channels for melt convection or movement. In some embodiments, the through-holes are designed to meet preset conditions in order to slow down the upward movement of silicon while satisfying convection or movement requirements. Further description is available. Figure 2 and Figure 3 This will not be elaborated upon here.

[0042] In some embodiments, when the heating component 120 is an induction heating component (such as...) Figure 1 As shown), the plate assembly 111 can also serve as a heat source to provide the heat required for crystal preparation (e.g., the heat energy required for crystal growth to dissolve the raw materials into a melt, and the temperature field required for crystal growth).

[0043] In some embodiments, the plate assembly 111 (e.g., the uppermost plate assembly) may be located at a predetermined distance below the melt surface. In some embodiments, the distance of the plate assembly 111 (e.g., the uppermost plate assembly) below the melt surface will affect the channels and paths for the melt raw materials required for crystal growth to be transported to the crystal growth surface, thereby affecting the quality of the grown crystal. Therefore, the predetermined distance needs to be within a predetermined range.

[0044] In some embodiments, the preset distance can be in the range of 10mm-50mm. In some embodiments, the preset distance can be in the range of 15mm-45mm. In some embodiments, the preset distance can be in the range of 20mm-40mm. In some embodiments, the preset distance can be in the range of 25mm-35mm. In some embodiments, the preset distance can be in the range of 28mm-32mm.

[0045] In some embodiments, to improve the stability of crystal growth, the plate assembly 111 (e.g., the lowest plate assembly) may be located near the midpoint of the height of the melt or heating assembly (e.g., an induction coil). In some embodiments, "nearby" may refer to a preset distance. In some embodiments, the preset distance may include ±50cm, ±40cm, ±30cm, ±20cm, ±10cm, ±8cm, ±6cm, ±4cm, ±2cm, ±1cm, etc. For example, "near the midpoint of the melt height" may include a range of ±30cm from half the melt height.

[0046] In some embodiments, the spacing between adjacent plate assemblies 111 can affect the temperature field near the crystal growth interface, the supply of raw materials (e.g., carbon, silicon) required for growth, and their transport path to the crystal growth interface. Therefore, the spacing between adjacent plate assemblies 111 must be within a preset range.

[0047] In some embodiments, the spacing between adjacent plate assemblies 111 can be in the range of 10mm-60mm. In some embodiments, the spacing between adjacent plate assemblies 111 can be in the range of 15mm-55mm. In some embodiments, the spacing between adjacent plate assemblies 111 can be in the range of 20mm-50mm. In some embodiments, the spacing between adjacent plate assemblies 111 can be in the range of 25mm-45mm. In some embodiments, the spacing between adjacent plate assemblies 111 can be in the range of 30mm-40mm. In some embodiments, the spacing between adjacent plate assemblies 111 can be in the range of 34mm-36mm.

[0048] In some embodiments, the crystal fabrication apparatus 100 may further include a cavity cover 130. In some embodiments, the shape and size of the cavity cover 130 may be compatible with the growth cavity 110. In some embodiments, the cavity cover 130 and the growth cavity 110 may be sealed or detachably connected (e.g., snap-fit).

[0049] In some embodiments, the crystal preparation apparatus 100 may further include a heat-insulating component 140 for heat-insulating the growth chamber 110. In some embodiments, the heat-insulating component 140 may be disposed around the outer periphery of the growth chamber 110. In some embodiments, the heat-insulating component 140 may be disposed around the outside of the heating component 120.

[0050] In some embodiments, the thermal insulation component 140 may include an upper thermal insulation component 141, a middle thermal insulation component 142, a cavity bottom thermal insulation component 143, and a lower thermal insulation component 144.

[0051] In some embodiments, such as Figure 1 As shown, the upper insulation component 141 can be located at the upper part of the growth chamber 110. In some embodiments, the middle insulation component 142 can be located at the lower part of the growth chamber 110 or below the upper insulation component 141. In some embodiments, the bottom insulation component 143 can be located at the bottom of the growth chamber 110. In some embodiments, the lower insulation component 144 can be located below the middle insulation component 142 and the bottom insulation component 143. In some embodiments, adjacent insulation components (e.g., the upper insulation component 141 and the middle insulation component 142, the middle insulation component 142 and the lower insulation component 144, the bottom insulation component 143 and the lower insulation component 144) can be detachably connected (e.g., fitted connection) to facilitate the removal and replacement of damaged insulation components.

[0052] In some embodiments, the insulation components (e.g., upper insulation component 141, middle insulation component 142, bottom insulation component 143, lower insulation component 144) may include bulk insulation material, granular insulation material, flocculent insulation material, sheet-like insulation material, etc. In some embodiments, the material of each insulation component may include quartz (silicon oxide), corundum (alumina), zirconium oxide, carbon fiber, ceramics, or other high-temperature resistant materials (e.g., rare earth metal borides, carbides, nitrides, silicides, phosphides, and sulfides, etc.). In some embodiments, the materials of each insulation component may be the same or different.

[0053] In some embodiments, the crystal preparation apparatus 100 may further include a seed crystal holder 150 for bonding the seed crystal. In some embodiments, the material of the seed crystal holder 150 may include graphite. For a related description of the seed crystal holder 150 and the seed crystal, please refer to other parts of this specification (e.g., Figure 6 (and its description), which will not be repeated here.

[0054] In some embodiments, the crystal preparation apparatus 100 may further include a connecting component 160 for connecting the seed crystal holder 150. In some embodiments, the connecting component 160 may be a cylinder, a pyramid, or the like. In some embodiments, the connecting component 160 may be integrally formed or formed by connecting multiple connecting parts to each other. In some embodiments, the material of the connecting component 160 may include, but is not limited to, graphite.

[0055] In some embodiments, the crystal preparation apparatus 100 may further include a power component (not shown) for driving the connecting component 160 to rotate and / or move up and down, so as to drive the seed crystal holder 150 to rotate and / or move up and down, so as to grow crystals.

[0056] In some embodiments, the crystal preparation apparatus 100 may further include a cover plate 170. In some embodiments, the cover plate 170 may be used to reduce crystal cracking. In some embodiments, the cover plate 170 may be located above the upper insulation component 141. In some embodiments, the cover plate 170 may be a cylinder, a pyramid, or the like. In some embodiments, the material of the cover plate 170 may be the same as or different from the material of the insulation component 140.

[0057] In some embodiments, such as Figure 1 As shown, the cavity cover 130, the upper heat insulation component 141 and the cover plate 170 are provided with through holes so that the connecting assembly 160 and the seed crystal holder 150 can pass through for rotation and / or up and down movement.

[0058] In some embodiments, the size of the hole in the cover plate 170 affects the amount of silicon volatilization. For example, if the hole is too large, heat will be lost through it, increasing the heat energy required from the heating components, which in turn leads to a higher melt temperature and increased silicon volatilization. Conversely, if the hole in the cover plate 170 is too small, the connecting component 160 and the seed crystal holder 150 cannot pass through for rotation and / or vertical movement, thus hindering normal crystal growth. Therefore, the diameter of the hole in the cover plate 170 must be within a preset range.

[0059] In some embodiments, the diameter of the hole in the cover plate 170 can be in the range of 20mm-150mm. In some embodiments, the diameter of the hole in the cover plate 170 can be in the range of 40mm-120mm. In some embodiments, the diameter of the hole in the cover plate 170 can be in the range of 50mm-100mm. In some embodiments, the diameter of the hole in the cover plate 170 can be in the range of 70mm-80mm.

[0060] It should be noted that the above description of the crystal preparation apparatus 100 is merely for illustration and explanation, and does not limit the scope of this application. Those skilled in the art can make various modifications and changes to the crystal preparation apparatus 100 under the guidance of this application. However, these modifications and changes are still within the scope of this application.

[0061] Figure 2 This is a schematic diagram of a through-hole on an exemplary board assembly according to some embodiments of this specification. Figure 3 This is a schematic diagram of a through-hole on an exemplary board assembly according to some embodiments of this specification.

[0062] In some embodiments, such as Figure 2 and Figure 3 As shown, the board assembly 111 may include through holes 1111. In some embodiments, the through holes 1111 may penetrate the board assembly 111. In some embodiments, the shape of the through holes 1111 may include regular or irregular shapes such as circles, ellipses, polygons, and stars. In some embodiments, the shapes of the through holes 1111 on a single board assembly 111 may be the same or different. In some embodiments, the shapes of the through holes 1111 on different board assemblies 111 may be the same or different.

[0063] In some embodiments, the through holes 1111 on adjacent plate assemblies 111 may be staggered. For example, as Figure 2 As shown, through hole 1111 is located on the upper plate assembly. Figure 2 (shown by the solid line in the middle) and the through hole 1111' on the lower plate assembly ( Figure 2 (As shown by the dashed lines) do not overlap. In some embodiments, interlacing can represent non-overlapping or partial overlap.

[0064] By staggering the through holes 1111 on adjacent plate assemblies 111, the convection of the melt in the growth chamber 110 can be adjusted, reducing the rising speed of volatile components (e.g., silicon), reducing the amount of volatile components (e.g., silicon) volatilizing from the surface of the melt, and reducing the silicon carbide particles generated by the reaction of volatile components (e.g., silicon vapor) with the graphite in the growth chamber 110. Furthermore, it can reduce the adhesion of volatilized silicon or generated silicon carbide particles to the upper insulation component, thus preventing contamination or damage to the insulation component, ensuring the insulation performance of the insulation component, and further ensuring normal crystal growth.

[0065] The ratio of the total opening area of ​​the vias 1111 to the surface area of ​​the plate assembly 111 containing the via 1111 affects the convection of the melt within the growth chamber 110, thus impacting normal crystal growth. For example, if the ratio is too large, the silicon rise rate cannot be effectively improved, and consequently, the volatilization of silicon on the melt surface cannot be effectively reduced. Conversely, if the ratio is too small, the resistance to the upward movement of the melt increases, making it difficult to ensure sufficient melt reaches the vicinity of the seed crystal, thus affecting the crystal growth rate. Therefore, in some embodiments, the ratio of the total opening area of ​​the vias 1111 to the surface area of ​​the plate assembly 111 containing the via 1111 needs to meet a preset requirement.

[0066] In some embodiments, for at least one of the at least one layer of plate assemblies 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 can be in the range of 30%-80%. In some embodiments, for at least one of the at least one layer of plate assemblies 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 can be in the range of 35%-75%. In some embodiments, for at least one of the at least one layer of plate assemblies 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 can be in the range of 40%-70%. In some embodiments, for at least one of the at least one layer of plate assemblies 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 can be in the range of 45%-65%. In some embodiments, for at least one of the at least one layer of plate assemblies 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 can be in the range of 50%-60%. In some embodiments, for at least one of the at least one layer of plate assembly 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 may be in the range of 52%-58%. In some embodiments, for at least one of the at least one layer of plate assembly 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 may be in the range of 54%-56%.

[0067] In some embodiments, for different plate assemblies 111, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 containing the through hole 1111 may be the same or different. In some embodiments, in the direction from the bottom to the top of the growth cavity 110, the ratio of the total opening area of ​​the through holes 1111 to the upper surface area of ​​the plate assembly 111 containing the through hole 1111 may gradually decrease or increase. For example, as... Figure 2 As shown, through hole 1111 is located on the upper plate assembly. Figure 2 (As shown by the solid line) The ratio of the total area of ​​the openings to the area of ​​the upper surface of the panel assembly can be less than the through-hole 1111' on the lower panel assembly. Figure 2 (As shown by the dashed line) The ratio of the total area of ​​the openings to the area of ​​the upper surface of the panel assembly.

[0068] In some embodiments, such as Figure 3As shown, the density of vias 1111 (e.g., the number of vias 1111 per unit area) can gradually decrease from the center to the edge of the plate assembly 111. In some embodiments, the via density near the center of the plate assembly 111 can be higher than the via density near the edge of the plate assembly 111. Accordingly, sufficient melt can be ensured to move upward from the vias 1111 located near the center of the plate assembly 111 to the seed crystal to crystallize and grow crystals, thereby improving melt convection and reducing excessive silicon consumption while ensuring crystal preparation efficiency.

[0069] It should be noted that, in the embodiments of this specification, "nearby" can refer to a preset distance. In some embodiments, the preset distance may include 10cm, 8cm, 6cm, 4cm, 2cm, 1cm, etc. In some embodiments, "near the center" of the board assembly 111 can refer to a board assembly area with the center of the board assembly 111 as the center and a radius of a preset distance. In some embodiments, "near the edge" of the board assembly 111 can refer to a board assembly area within a preset distance from the edge of the board assembly 111.

[0070] If the ratio of the via density near the center of the plate assembly 111 to the via density near the edge of the plate assembly 111 is too small, it will lead to natural nucleation of silicon carbide on the inner wall of the growth cavity 110 or a high natural nucleation rate. Conversely, if the ratio is too large, it will cause the crystal center to grow too quickly, easily forming encapsulation and cracking. Therefore, in some embodiments, the ratio of the via density near the center of the plate assembly 111 to the via density near the edge of the plate assembly 111 needs to be within a preset range.

[0071] In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 20:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 18:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 16:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 14:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 12:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 10:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 8:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 6:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1:1 to 5:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 1.5:1 to 4.5:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 2:1 to 4:1. In some embodiments, the ratio of the via density near the center of the board assembly 111 to the via density near the edge of the board assembly 111 can be in the range of 2.5:1 to 3.5:1. In some embodiments, the ratio of the through-hole density near the center of the board assembly 111 to the through-hole density near the edge of the board assembly 111 can be in the range of 2.8:1 to 3.2:1.

[0072] The diameter of the through-hole 1111 affects the convection of the melt within the growth chamber 110, thus impacting normal crystal growth. For example, if the diameter of the through-hole 1111 is too large, it cannot effectively improve the silicon rising speed, and consequently, cannot effectively reduce silicon volatilization on the melt surface. Conversely, if the diameter of the through-hole 1111 is too small, the resistance to the upward movement of the melt increases, making it impossible to ensure that a sufficient amount of melt reaches the vicinity of the seed crystal, thereby affecting the crystal growth rate. Therefore, in some embodiments, the diameter of the through-hole 1111 must meet preset requirements.

[0073] In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-10mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-9mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-8mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-7mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-6mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-5mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.1mm-5mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 0.5mm-4.5mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 1mm-4mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 1.5mm-3.5mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 2mm-3mm. In some embodiments, the diameter of the through hole 1111 can be in the range of 2.4mm-2.6mm.

[0074] Figure 4 This is a partial structural schematic diagram of an exemplary cavity cover and upper insulation component according to some embodiments of this specification.

[0075] As mentioned earlier, during crystal preparation, silicon moves upward from the bottom of the growth chamber 110, and may even evaporate into a gaseous state, continuing to rise as silicon vapor. This silicon vapor may overflow the chamber cover 130 and condense upon cooling, adhering to the surface of the upper insulation component 141, affecting its insulation performance. Therefore, in some embodiments, such as... Figure 4 As shown, the cavity cover 130 and the upper insulation component 141 may have a gap 131, which can be filled with carbon powder so that the volatilized silicon vapor reacts with the carbon powder. This can prevent the silicon vapor from overflowing and condensing upon cooling and adhering to the surface of the upper insulation component 141, or prevent the silicon carbide particles generated by the reaction of silicon vapor with the growth cavity 110 from adhering to the insulation component and affecting its insulation performance.

[0076] In some embodiments, such as Figure 4 As shown, the cavity cover 130 may also include a raised structure 132. Because the temperature near the raised structure 132 is lower (below the melt temperature), some silicon vapor can condense at the raised structure 132, thus slowing down or reducing the overflow of silicon vapor and reducing the degree of contamination of the upper insulation assembly 141. After crystal growth is completed, the raised structure 132 can be cleaned for subsequent use.

[0077] Figure 5 This is a schematic diagram of the structure of an exemplary growth chamber according to some embodiments of this specification.

[0078] As mentioned above, in the crystal preparation process, the raw materials need to be melted into a melt (liquid state) and crystal growth is carried out based on the melt. The growth chamber 110 needs to provide the carbon source required for crystal growth. Therefore, the temperature at the bottom (or lower middle part) of the growth chamber 110 is relatively high, and the carbon is consumed relatively quickly.

[0079] Therefore, in some embodiments, the wall thickness of the sidewall of the growth chamber 110 is along the direction from the top to the bottom of the growth chamber 110 (e.g., Figure 5 The direction indicated by the middle arrow gradually increases, which can prevent the bottom from being consumed too much and becoming thinner, and further increase the number of times the growth chamber 110 can be used.

[0080] Figure 6 This is a schematic diagram of the structure of an exemplary seed crystal holder and a seed crystal according to some embodiments of this specification.

[0081] In the crystal preparation process, if the seed crystal is too thin, it is easy to burn through, which will affect the crystal preparation effect. Also, because the seed crystal is too thin, the seed crystal holder may inevitably come into contact with the melt, generating crystals with different crystal forms and / or crystal orientations than the seed crystal, thus producing crystal defects. On the other hand, if a thicker seed crystal is used directly, the cost of seed crystal preparation will be greatly increased.

[0082] Therefore, in some embodiments, the seed crystal 180 may include at least two layers of seed crystals, wherein the seed crystal used for crystal growth (i.e. the bottommost seed crystal in direct contact with the melt) has a higher quality, while the quality of other seed crystals may be relatively lower, thereby reducing costs while increasing the overall thickness of the seed crystal.

[0083] In some embodiments, such as Figure 6 As shown, at least two seed crystal layers may include a first seed crystal 181 and a second seed crystal 182, wherein the mass of the first seed crystal 181 may be lower than the mass of the second seed crystal 182.

[0084] In some embodiments, provided that the second seed crystal 182 meets the crystal growth requirements, the thickness of the first seed crystal 181 can be greater than the thickness of the second seed crystal 182, so as to further reduce the cost of the seed crystal 180.

[0085] In some embodiments, the bonding method between the seed crystal holder 150 and the first seed crystal 181, and between the first seed crystal 181 and the second seed crystal 182, may include, but is not limited to, bonding, gluing, etc.

[0086] Since the seed crystal holder 150 inevitably has certain pores, the gaseous material accumulated in the gap or pore area on the back side of the seed crystal (e.g., the bonding surface between the first seed crystal 181 and the seed crystal holder 150) will escape, resulting in defects (e.g., planar hexagonal void defects) in the final crystal.

[0087] Therefore, in some embodiments, such as Figure 6 As shown, graphite paper 190 can be filled between the seed crystal holder 150 and the seed crystal 180 (first seed crystal 181). The graphite paper 190 is relatively soft and has high flatness, which can reduce the porosity of the bonding surface, prevent uneven heating on the back side of the seed crystal, reduce the generation of subsequent defects, and at the same time improve the bonding strength between the seed crystal holder 150 and the seed crystal 180 (e.g., the first seed crystal 181).

[0088] Figure 7 This is a flowchart illustrating an exemplary crystal fabrication method according to some embodiments of this specification. In some embodiments, process 700 may be performed by one or more components in a crystal fabrication apparatus (e.g., crystal fabrication apparatus 100). In some embodiments, process 700 may be performed automatically by a control system. For example, process 700 may be implemented by control commands, based on which the control system controls the various components to complete the various operations of process 700. In some embodiments, process 700 may be performed semi-automatically. For example, one or more operations of process 700 may be performed manually by an operator. In some embodiments, when completing process 700, one or more additional operations not described may be added, and / or one or more operations discussed herein may be removed. Additionally, Figure 7 The order of operations shown is not restrictive. Figure 7 As shown, process 700 includes the following steps.

[0089] Step 710: Place the raw material into the growth chamber.

[0090] In some embodiments, the raw material may refer to the raw materials required for crystal growth. For example, when growing silicon carbide crystals, the raw material may include silicon (e.g., silicon powder, silicon wafers, silicon blocks). As another example, when growing silicon carbide crystals, the raw material may include silicon and carbon (e.g., carbon powder, carbon blocks, carbon particles). In some embodiments, including carbon powder, carbon blocks, or carbon particles in the raw material can increase the number of uses of the growth chamber. In some embodiments, the raw material may also include a flux to improve the solubility of carbon in silicon. In some embodiments, the flux may include, but is not limited to, aluminum, silicon-chromium alloys, Li-Si alloys, Ti-Si alloys, Fe-Si alloys, Sc-Si alloys, and Co-Si alloys.

[0091] In some embodiments, at least one plate assembly may be disposed within the growth chamber. For a description of the growth chamber (e.g., growth chamber 110) and at least one plate assembly (e.g., plate assembly 111), please refer to other parts of this specification (e.g., Figures 1-5 (and its description), which will not be repeated here.

[0092] Step 720: The growth chamber is heated by the heating component to melt the raw material into a melt.

[0093] For example, when growing silicon carbide crystals, the raw materials melt to form a solution of carbon in silicon, which serves as the liquid raw material for crystal growth.

[0094] For a description of the heating assembly (e.g., heating assembly 120), please refer to other parts of this specification (e.g., Figure 1 (and its description), which will not be repeated here.

[0095] In some embodiments, to improve the utilization rate of raw materials, the ratio of melt height to growth chamber height needs to be within a preset range. In some embodiments, the ratio of melt height to growth chamber height can be in the range of 1:1 to 1:5. In some embodiments, the ratio of melt height to growth chamber height can be in the range of 1:1.5 to 1:4.5. In some embodiments, the ratio of melt height to growth chamber height can be in the range of 1:2 to 1:4. In some embodiments, the ratio of melt height to growth chamber height can be in the range of 1:2.5 to 1:3.5. In some embodiments, the ratio of melt height to growth chamber height can be in the range of 1:2.8 to 1:3.

[0096] In some embodiments, to improve the stability of crystal growth, the melt surface may be located near the midpoint of the height of the heating component (e.g., an induction coil). In some embodiments, "nearby" may refer to a preset distance. In some embodiments, the preset distance may include ±50cm, ±40cm, ±30cm, ±20cm, ±10cm, ±8cm, ±6cm, ±4cm, ±2cm, ±1cm, etc. For example, after the raw material is melted into a melt, the melt surface may be located within a range of ±30cm of half the height of the heating component (e.g., an induction coil).

[0097] Step 730: Attach the seed crystal to the seed crystal holder.

[0098] In some embodiments, the seed crystal may include at least two layers of seed crystals. In some embodiments, the at least two layers of seed crystals may include a first seed crystal and a second seed crystal, wherein the first seed crystal may be bonded to a seed crystal holder, and the second seed crystal may be bonded to the first seed crystal. In some embodiments, the mass of the first seed crystal may be lower than the mass of the second seed crystal.

[0099] In some embodiments, before bonding the seed crystal to the seed crystal holder, graphite paper may be adhered to the seed crystal holder, with the graphite paper positioned between the seed crystal holder and the seed crystal. In some embodiments, the seed crystal and / or graphite paper may be concentric with the seed crystal holder.

[0100] In some embodiments, the thickness of the graphite paper can be in the range of 0.5 mm to 1 mm. In some embodiments, the thickness of the graphite paper can be in the range of 0.6 mm to 0.9 mm. In some embodiments, the thickness of the graphite paper can be in the range of 0.5 mm to 1 mm. In some embodiments, the thickness of the graphite paper can be in the range of 0.7 mm to 0.8 mm.

[0101] In some embodiments, to ensure the bonding strength between the graphite paper, the first seed crystal, and the second seed crystal, and to guarantee crystal quality, the flatness of the surface of the first seed crystal must meet preset conditions. In some embodiments, the flatness of the surface of the first seed crystal bonded to the graphite paper can be less than 0.01 mm. In some embodiments, the flatness of the surface of the first seed crystal bonded to the second seed crystal can be in the range of 0.005 mm to 0.008 mm. In some embodiments, the flatness of the surface of the first seed crystal bonded to the second seed crystal can be in the range of 0.006 mm to 0.007 mm.

[0102] For further descriptions of the seed crystal (e.g., seed crystal 180) and the seed crystal holder (e.g., seed crystal holder 150), please refer to other parts of this specification (e.g., Figure 6 (and its description), which will not be repeated here.

[0103] Step 740: Lower the seed crystal holder with the seed crystal attached so that the seed crystal comes into contact with the melt.

[0104] In some embodiments, the connecting component can be lowered by the power component, thereby lowering the seed crystal holder so that the seed crystal comes into contact with the melt.

[0105] Step 750: Based on the seed crystal and the melt, prepare the crystal.

[0106] In some embodiments, the connecting component can be rotated and / or moved up and down by the power component, thereby causing the seed crystal holder to rotate and / or move up and down, and the melt can be condensed and crystallized at the seed crystal to grow a crystal.

[0107] During crystal growth, convection occurs in the melt within the growth chamber. Silicon from the lower part moves upwards. Some of this silicon is blocked by the plate assemblies within the growth chamber, while some continues to move upwards through the through-holes in the plate assemblies. Because the through-holes on adjacent plate assemblies are staggered, the silicon continuing to move upwards is blocked by the plate assembly above. This process repeats, significantly reducing the amount of silicon convection to the upper surface of the melt. Consequently, this reduces silicon volatilization from the upper surface of the melt, further reducing the contamination level of the insulation components, maintaining their insulation performance, and ultimately ensuring normal crystal growth.

[0108] It should be noted that the above description of process 700 is merely for illustration and explanation, and does not limit the scope of this application. Those skilled in the art can make various modifications and changes to process 700 under the guidance of this application. However, these modifications and changes are still within the scope of this application.

[0109] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) At least one plate assembly is provided in the growth chamber. The material of the plate assembly includes graphite, which can be used as a carbon source to provide the raw materials required for the preparation of silicon carbide crystals; (2) The plate assembly includes through holes. The through holes on adjacent plate assemblies are designed to be staggered, which can adjust the convection of the melt in the growth chamber, reduce the rising speed of volatile components (e.g., silicon), reduce the volatilization of volatile components (e.g., silicon) on the surface of the melt, reduce the excessive consumption of volatile components, and reduce the silicon carbide particles generated by the reaction of volatile components (e.g., silicon vapor) with the growth chamber. Furthermore, it can reduce the degree of contamination of the heat preservation assembly, ensure the heat preservation performance of the heat preservation assembly, and further ensure the normal growth of the crystal; (3) A coating or a shielding ring is provided on the upper part of the inner wall of the growth chamber within a preset range, which can avoid The silicon on the surface of the non-melting body reacts with the carbon on the sidewall of the growth chamber to spontaneously nucleate and crystallize; (4) There are gaps between the chamber cover and the upper insulation component, and the gaps are filled with carbon powder. The carbon powder can react with the volatilized silicon vapor to prevent silicon vapor from overflowing into the insulation component, or to prevent silicon carbide particles generated by the reaction of silicon vapor with the growth chamber from adhering to the insulation component and affecting its insulation performance; (5) The chamber cover includes a raised structure, which can allow some silicon vapor to condense at the raised structure to slow down or reduce the overflow of silicon vapor and reduce the degree of contamination of the insulation component; (6) The seed crystal includes at least two layers of seed crystal, which can increase its thickness and reduce the risk of it being burned through, and further ensure the quality of the crystal produced; (7) The mass of the first seed crystal bonded to the seed crystal holder can be lower than the mass of the second seed crystal bonded to the first seed crystal to reduce the seed crystal cost and further reduce the crystal preparation cost. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced can be any one or a combination of the above, or any other possible beneficial effects.

[0110] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0111] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0112] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0113] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0114] For each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, and documents, referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0115] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A crystal preparation apparatus for preparing crystals using a liquid-phase method, characterized in that, The device includes: A growth chamber, wherein at least two plate assemblies are disposed within the growth chamber, wherein... Each of the at least two-layer board assembly includes a through hole; The diameter of the through hole is in the range of 0.1mm-10mm; The density of the through holes gradually decreases from the center to the edge of the plate assembly; In the direction from the bottom to the top of the growth chamber, the ratio of the total opening area of ​​the through holes on one layer of the plate assembly to the upper surface area of ​​the plate assembly gradually decreases. Heating assembly for heating the growth chamber; Connecting components for connecting the seed crystal holder to support the seed crystal; and A power component is used to drive the connecting component to rotate and / or move up and down, so as to drive the seed crystal holder to rotate and / or move up and down.

2. The crystal preparation apparatus according to claim 1, characterized in that, The plate assembly is located in the melt within the growth chamber, and at a predetermined distance below the melt surface.

3. The crystal preparation apparatus according to claim 1, characterized in that, The spacing between adjacent plate assemblies is in the range of 10mm-60mm.

4. The crystal preparation apparatus according to claim 1, characterized in that, The heating assembly includes an induction coil, which is arranged around the periphery of the growth chamber. The height ratio of the growth chamber to the induction coil is in the range of 1:1 to 1:

5.

5. The crystal preparation apparatus according to claim 1, characterized in that, The ratio of the through-hole density near the center of the board assembly to the through-hole density near the edge of the board assembly is in the range of 1:1 to 20:

1.

6. The crystal preparation apparatus according to claim 1, characterized in that, The upper part of the sidewall of the growth chamber is coated with a coating or a shielding ring is provided within a predetermined range.

7. The crystal preparation apparatus according to claim 1, characterized in that, The device also includes a cavity cover and an upper heat insulation component, and the gap between the cavity cover and the upper heat insulation component is filled with carbon powder.

8. The crystal preparation apparatus according to claim 7, characterized in that, The cavity cover includes a raised structure.

9. The crystal preparation apparatus according to claim 1, characterized in that, The apparatus is used to prepare silicon carbide crystals. The growth chamber is made of graphite, and the wall thickness of the sidewall of the growth chamber gradually increases from the top to the bottom of the growth chamber.

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