Method for growing low-defect crystal
By obtaining and using the deformation coefficients of quartz crucibles and graphite crucibles to correct the ratio of crystal growth rate to the crucible lift rate, the problem of inaccurate liquid mouth distance control in the CZ method is solved, and the stable growth of low-defect crystals is achieved.
Patent Information
- Application Number
- CN202411998366.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-11
AI Technical Summary
It is difficult to accurately control the liquid gap during the existing CZ method to grow crystals, making it difficult to obtain a stable temperature gradient at the interface of the growing crystal, and thus it is difficult to achieve the growth of low-defect crystals.
By obtaining the deformation coefficients of the quartz crucible and the graphite crucible, and correcting the ratio of the lifting and falling rate of the quartz crucible to the crystal growth rate based on these coefficients, the liquid port distance is accurately controlled.
Accurate control of the liquid port distance is achieved, ensuring the stability of the temperature gradient of the growing crystal interface, thereby growing low-defect crystals.
Smart Images
Figure CN119800488A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a method for growing low-defect crystals. Background Art
[0002] The current mainstream method for growing single crystal silicon is the Czochralski method (CZ method, also known as the Czochralski method). Figure 1 The thermal field structure shown is used to grow single crystal silicon: the polysilicon material filled in the graphite crucible 11 and the quartz crucible 12 is heated by the heater 17 to melt it into silicon melt 13, and then the seed crystal 15 is immersed in the silicon melt 13, and the pulling speed of the seed crystal 15 is controlled in the silicon crystal growth temperature zone to grow crystal 16.
[0003] During the CZ method of growing crystals, under specific thermal field conditions, if the growth rate is too fast, crystal defects such as Crystal Originated Particles (COP) and Oxidation-Induced Stacking Faults (OSF) will be generated, which will cause leakage risks during the integrated circuit manufacturing process; while if the growth rate is too slow, A / B interstitial defects (A / B interstitial defects) will be generated, which will cause problems such as metal impurity absorption during the integrated circuit manufacturing process.
[0004] Only with a suitable critical growth rate can low-defect crystals without the above defects be produced. The critical growth rate is equal to the ratio of the crystal growth rate to the temperature gradient of the growing crystal interface. Only under a specific temperature gradient can the crystal growth rate be more accurately controlled. Figure 1 As shown, the structures that affect the temperature gradient in the thermal field structure mainly include the guide tube 14, the heater 17, the insulation barrel 18 and the graphite crucible 11, etc. The relative positions of these structures determine the temperature gradient of the growing crystal interface, wherein the size of the temperature gradient mainly depends on the height of the distance between the guide tube 14 and the surface of the silicon melt 13, wherein the height of the distance between the guide tube 14 and the surface of the silicon melt 13 is also called the liquid mouth distance (melt gap), and a smaller liquid mouth distance will obtain a larger temperature gradient, thereby obtaining a higher crystal growth rate to grow low-defect crystals, that is, being able to accurately control the liquid mouth distance is the key to growing low-defect crystals.
[0005] However, in the process of growing crystals by the CZ method of the related art, it is difficult to accurately control the liquid-to-mouth distance, which makes it difficult to obtain a stable temperature gradient at the interface of the growing crystal, thereby making it difficult to achieve the growth of low-defect crystals. Summary of the invention
[0006] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.
[0007] In view of the existing problems, the present application provides a method for growing low-defect crystals, comprising:
[0008] Obtaining deformation coefficients of the quartz crucible and the graphite crucible at a plurality of positions from an initial liquid level position to an end liquid level position of the molten liquid contained in the quartz crucible;
[0009] Measuring the inner radius of the quartz crucible at each of the position points before drawing of the current furnace;
[0010] Based on the deformation coefficients of the quartz crucible and the graphite crucible at each of the positions and the inner radius of the quartz crucible at each of the positions before drawing of the current furnace, the inner radius of the quartz crucible at each of the positions after drawing of the current furnace is obtained;
[0011] Based on the inner radius of the quartz crucible at each of the positions after pulling of the current furnace, the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the molten liquid of the current furnace is at each of the positions is obtained.
[0012] Exemplarily, the deformation coefficients of the quartz crucible and the graphite crucible at multiple positions from the initial liquid level position to the final liquid level position of the molten liquid contained in the quartz crucible are obtained, including:
[0013] The first heat in the life cycle of the graphite crucible:
[0014] Respectively measuring the inner radius of the quartz crucible and the graphite crucible at each of the position points before and after drawing;
[0015] The remaining heats in the life cycle of the graphite crucible:
[0016] The deformation coefficients of the quartz crucible and the graphite crucible at each of the positions are obtained based on the inner radii of the quartz crucible and the graphite crucible at each of the positions before and after drawing in the previous heat.
[0017] Exemplarily, the remaining furnaces within the service life of the graphite crucible further include a step of measuring the inner radius of the graphite crucible at each of the position points after drawing of the current furnace.
[0018] Exemplarily, based on the inner radius of the quartz crucible at each of the position points after pulling of the current furnace, the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the molten liquid of the current furnace is at each of the position points is obtained, including:
[0019] Obtaining the density of the melt and the density of the crystal of the current heat, and measuring the inner radius of the crystal when the liquid level of the melt of the current heat is at each of the position points;
[0020] Based on the density of the melt in the current furnace, the density of the crystal, the inner radius of the crystal when the liquid level of the melt is at each of the position points, and the inner radius of the quartz crucible at each of the position points after pulling, the ratio of the quartz crucible lifting rate and the crystal growth rate when the liquid level of the melt in the current furnace is at each of the position points is obtained.
[0021] Exemplarily, the ratio of the lifting rate of the quartz crucible to the crystal growth rate when the liquid level of the molten liquid in the current furnace is at each of the positions is obtained by the following formula based on the density of the molten liquid in the current furnace, the density of the crystal, the inner radius of the crystal when the liquid level of the molten liquid is at each of the positions, and the inner radius of the quartz crucible at each of the positions after pulling:
[0022]
[0023] Wherein, CLR represents the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the melt of the current furnace is at each of the positions, ρ s represents the density of the melt in the current heat, ρ L Indicates the density of the crystal in the current batch, r CRY represents the inner radius of the crystal when the liquid level of the melt in the current furnace is at each of the position points, and r′1_q represents the inner radius of the quartz crucible at each of the position points after pulling in the current furnace.
[0024] Exemplarily, the inner radius of the quartz crucible at each of the positions after drawing in the current furnace is obtained by the following formula based on the deformation coefficients of the quartz crucible and the graphite crucible at each of the positions and the inner radius of the quartz crucible at each of the positions before drawing in the current furnace:
[0025] r′1_q=(1-kh)*r1_q
[0026] Among them, r′1_q represents the inner radius of the quartz crucible at each of the said position points after drawing of the current furnace, k represents the deformation coefficient of the quartz crucible at each of the said position points, h represents the deformation coefficient of the graphite crucible at each of the said position points, and r1_q represents the inner radius of the quartz crucible at each of the said position points before drawing of the current furnace.
[0027] Exemplarily, the deformation coefficients of the quartz crucible and the graphite crucible at each of the positions are obtained by the following formula based on the inner radius of the quartz crucible and the graphite crucible at each of the positions before and after drawing in the previous heat:
[0028]
[0029] Among them, k represents the deformation coefficient of the quartz crucible at each of the position points, h represents the deformation coefficient of the graphite crucible at each of the position points, r0_q and r′0_q respectively represent the inner radius of the quartz crucible at each of the position points before and after drawing of the previous heat, r0_g and r′0_g respectively represent the inner radius of the graphite crucible at each of the position points before and after drawing of the previous heat.
[0030] Exemplarily, a laser diameter gauge is used to measure the inner radius of the quartz crucible and the graphite crucible at each of the positions before and after drawing of the first furnace, the inner radius of the quartz crucible at each of the positions before drawing of the remaining furnaces, and the inner radius of the graphite crucible at each of the positions after drawing of the remaining furnaces.
[0031] Exemplarily, a CCD camera is used to measure the inner radius of the crystal when the liquid level of the melt of the current heat is at each of the position points.
[0032] Exemplarily, the number of furnace cycles of the graphite crucible is greater than or equal to 40 and less than or equal to 100.
[0033] The method for growing low-defect crystals in the embodiment of the present application obtains the deformation coefficients of the quartz crucible and the graphite crucible, and corrects the ratio of the quartz crucible lifting rate to the crystal growth rate based on the deformation coefficients of the quartz crucible and the graphite crucible, so as to obtain an accurate ratio of the quartz crucible lifting rate to the crystal growth rate, thereby being able to accurately control the liquid mouth distance, and further to obtain a stable temperature gradient at the interface of the growing crystal, thereby achieving the growth of low-defect crystals. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.
[0035] In the attached figure:
[0036] Figure 1 A schematic diagram showing a thermal field structure of a growing crystal in the related art;
[0037] Figure 2 A line graph showing the ratio of the preset and measured crystal growth rate to the crucible lifting rate of the related art;
[0038] Figure 3 A flow chart showing a method for growing a low-defect crystal according to an exemplary embodiment of the present application;
[0039] Figure 4 A line graph showing the ratio of the preset and measured crystal growth rate to the crucible lifting rate according to an exemplary embodiment of the present application;
[0040] Figure 5 A schematic diagram showing the distribution of qualified areas and high defect areas of comparative example crystals and example crystals is shown. DETAILED DESCRIPTION
[0041] Next, the present application will be described more completely in conjunction with the accompanying drawings, in which embodiments of the present application are shown. However, the present application can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, for clarity, the sizes and relative sizes of layers and regions may be exaggerated. The same reference numerals throughout represent the same elements.
[0042] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.
[0043] Spatially relative terms such as "under," "below," "below," "under," "above," "above," etc., may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" the other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.
[0044] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "a", "an", and "said / the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.
[0045] Embodiments of the application are described herein with reference to cross-sectional views that are schematic diagrams of ideal embodiments (and intermediate structures) of the present application. Thus, variations from the shapes shown due to, for example, manufacturing techniques and / or tolerances can be expected. Therefore, embodiments of the present application should not be limited to the specific shapes of the zones shown herein, but include shape deviations due to, for example, manufacturing. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges, rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the actual shape of the region of the device and are not intended to limit the scope of the present application.
[0046] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by ordinary technicians in the field of this application. It will also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an ideal or overly formal sense unless expressly defined as such herein.
[0047] In order to thoroughly understand the present application, detailed steps and structures will be presented in the following description to illustrate the technical solution proposed by the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementations.
[0048] For low-defect crystals with a yield greater than 93% (COP free yield greater than 93% as detected by copper rust, SPx and other testing equipment), every 1% increase in yield can significantly reduce costs and greatly improve product stability and competitiveness at the client end.
[0049] Although the purpose of achieving a suitable critical growth rate can be achieved by adjusting the pulling speed, the problem is that if the liquid mouth distance is unstable, the preset growth rate cannot be determined. Therefore, the control of the liquid mouth distance is the key to improving the crystal yield. If the setting of the liquid mouth distance deviates from the actual liquid mouth distance value, it will directly affect the temperature gradient, thereby changing the critical growth rate and causing a decrease in the crystal yield. Therefore, if the growth of low-defect crystals with a yield greater than 93% is to be achieved, especially if the growth of low-defect crystals with a yield greater than 95% is to be achieved, the liquid mouth distance needs to be accurately controlled. The control of the liquid mouth distance is determined by the ratio of the crystal growth rate to the crucible lifting rate (i.e., the lifting rate of the quartz crucible) when the liquid level of the silicon melt is at different positions. Therefore, it is necessary to accurately set the ratio of the crystal growth rate to the crucible lifting rate (i.e., the lifting rate of the quartz crucible) when the liquid level of the silicon melt is at different positions.
[0050] The ratio of the crystal growth rate to the crucible lifting and lowering rate is determined by the density and radius of the crystal, and the density and radius of the molten silicon. The density of the crystal and the density of the molten silicon are constants. Therefore, the control of the liquid mouth distance mainly depends on the radius of the crystal and the radius of the molten silicon. The radius of the crystal can be accurately measured by a CCD camera (charge coupled device camera), and the radius of the molten silicon is equal to the inner radius of the quartz crucible at the liquid level of the molten silicon (the radius of the inner surface of the quartz crucible). The inner radius of the quartz crucible is generally measured before the crystal is pulled.
[0051] However, the inventors of the present application have found that the quartz crucible will deform during the crystal pulling process, causing the inner radius of the quartz crucible to change, affecting the radius of the silicon melt; at the same time, the graphite crucible will age during its use period, and the aging of the quartz crucible will affect the deformation of the quartz crucible, thereby affecting the inner radius of the quartz crucible, and thus affecting the radius of the silicon melt. Figure 2As shown, the deformation of the quartz crucible and the aging of the graphite crucible will cause the ratio of the quartz crucible lifting rate and the crystal growth rate measured in the comparative example to deviate from the ratio of the quartz crucible lifting rate and the crystal growth rate preset in the comparative example, wherein the ratio of the quartz crucible lifting rate and the crystal growth rate measured in the comparative example refers to the actual ratio of the quartz crucible lifting rate and the crystal growth rate that makes the liquid mouth distance meet the requirements during the growth process, that is, when the crystal is grown according to the ratio of the quartz crucible lifting rate and the crystal growth rate preset in the comparative example, the liquid mouth distance cannot be accurately controlled; wherein, CLR represents the ratio of the quartz crucible lifting rate and the crystal growth rate, crystal length represents the crystal length, the crystal length corresponds to the liquid level position of the melt, and the liquid level of the melt decreases with the increase of the crystal length. That is, the deformation of the quartz crucible and the aging of the graphite crucible will cause the inner radius of the quartz crucible to change, thereby causing the radius of the silicon melt to change, which in turn makes it impossible to obtain an accurate ratio of the crystal growth rate to the crucible lifting rate, making it difficult to accurately control the liquid mouth distance and achieve the growth of low-defect crystals.
[0052] Therefore, in view of the existence of the aforementioned technical problems, the present application proposes a method for growing low-defect crystals, such as Figure 3 As shown, it includes the following steps:
[0053] Step S1, obtaining deformation coefficients of a quartz crucible and a graphite crucible at a plurality of positions from an initial liquid level position to an end liquid level position of a molten liquid contained in the quartz crucible;
[0054] Step S2, measuring the inner radius of the quartz crucible at each position point before drawing of the current furnace;
[0055] Step S3, based on the deformation coefficients of the quartz crucible and the graphite crucible at each position point and the inner radius of the quartz crucible at each position point before drawing of the current furnace, obtaining the inner radius of the quartz crucible at each position point after drawing of the current furnace;
[0056] Step S4, based on the inner radius of the quartz crucible at each position point after pulling of the current furnace, obtain the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the molten liquid of the current furnace is at each position point.
[0057] The method for growing low-defect crystals in the embodiment of the present application obtains the deformation coefficients of the quartz crucible and the graphite crucible, and corrects the ratio of the quartz crucible lifting rate to the crystal growth rate based on the deformation coefficients of the quartz crucible and the graphite crucible, so as to obtain an accurate ratio of the quartz crucible lifting rate to the crystal growth rate, thereby being able to accurately control the liquid mouth distance, and further to obtain a stable temperature gradient at the interface of the growing crystal, thereby achieving the growth of low-defect crystals.
[0058] Below, reference Figures 3 to 5The method for growing low-defect crystals of the present application is described in detail, wherein: Figure 3 A flow chart showing a method for growing a low-defect crystal according to an exemplary embodiment of the present application is shown. Figure 4 The following is a line graph showing the ratio of the preset and measured crystal growth rate to the crucible lifting rate according to an exemplary embodiment of the present application. For example, the method for growing low-defect crystals of the present application is applied to the CZ method. Figure 5 A schematic diagram showing the distribution of qualified areas and high defect areas of comparative example crystals and example crystals is shown.
[0059] For example, Figure 3 As shown, the method for growing low-defect crystals of the present application comprises the following steps:
[0060] First, step S1 is performed to obtain deformation coefficients of the quartz crucible and the graphite crucible at multiple positions from the initial liquid level position to the final liquid level position of the melt contained in the quartz crucible.
[0061] In one example, the melt contained in the quartz crucible is silicon melt, the initial liquid level position of the melt refers to the liquid level position of the melt before drawing, and the final liquid level position of the melt refers to the liquid level position of the melt after drawing, wherein the initial liquid level position of the melt is higher than the final liquid level position of the melt. Exemplarily, the multiple position points from the initial liquid level position to the final liquid level position of the melt contained in the quartz crucible include the initial liquid level position of the melt, the final liquid level position of the melt, and multiple position points located between the initial liquid level position of the melt and the final liquid level position of the melt, and the multiple position points refer to multiple height position points, and the multiple position points are spaced along the height direction of the quartz crucible; more specifically, the multiple position points can be spaced at equal intervals along the height direction of the quartz crucible. Exemplarily, the number of position points should be reasonably set according to actual needs, and this application does not limit this.
[0062] In one example, deformation coefficients of a quartz crucible and a graphite crucible at multiple positions from an initial liquid level position to an end liquid level position of a molten liquid contained in the quartz crucible are obtained, including: in the first furnace within the service life of the graphite crucible: measuring the inner radius of the quartz crucible and the graphite crucible at each position before and after drawing, respectively; in the remaining furnaces within the service life of the graphite crucible: obtaining the deformation coefficients of the quartz crucible and the graphite crucible at each position based on the inner radius of the quartz crucible and the graphite crucible at each position before and after drawing of the previous furnace.
[0063] In one example, the remaining heats in the graphite crucible use cycle also include a step of measuring the inner radius of the graphite crucible at each position point after drawing in the current heat. Exemplarily, a laser diameter gauge can be used to measure the inner radius of the graphite crucible at each position point after drawing in the remaining heats.
[0064] In one example, during the life cycle of the graphite crucible, the graphite crucible will not be replaced, and a new quartz crucible needs to be replaced after each furnace drawing is completed during the life cycle of the graphite crucible. Exemplarily, the number of furnaces during the life cycle of the graphite crucible is greater than or equal to 40 and less than or equal to 100. Exemplarily, a laser diameter gauge can be used to measure the inner radius of the quartz crucible and the graphite crucible at each position point before and after the first furnace drawing. Exemplarily, the inner radius of the quartz crucible at each position point refers to the radius of the inner surface of the quartz crucible at each position point, and the inner radius of the graphite crucible at each position point refers to the radius of the inner surface of the graphite crucible at each position point.
[0065] In one example, the deformation coefficients of the quartz crucible and the graphite crucible at each position point are obtained by the following formula based on the inner radius of the quartz crucible and the graphite crucible at each position point before and after drawing in the previous heat:
[0066]
[0067] Among them, k represents the deformation coefficient of the quartz crucible at each position point, h represents the deformation coefficient of the graphite crucible at each position point, r0_q and r′0_q respectively represent the inner radius of the quartz crucible at each position point before and after drawing of the previous heat, r0_g and r′0_g respectively represent the inner radius of the graphite crucible at each position point before and after drawing of the previous heat.
[0068] Next, step S2 is performed to measure the inner radius of the quartz crucible at each position point before drawing of the current furnace. Exemplarily, since a new quartz crucible needs to be replaced for each furnace drawing, the inner radius of the quartz crucible at each position point needs to be measured before each furnace drawing. Exemplarily, a laser diameter gauge can be used to measure the inner radius of the quartz crucible at each position point before drawing of the current furnace, wherein the inner radius of the quartz crucible at each position point before drawing of the current furnace includes the inner radius of the quartz crucible at each position point before drawing of the first furnace and the inner radius of the quartz crucible at each position point before drawing of the remaining furnaces.
[0069] Next, step S3 is performed to obtain the inner radius of the quartz crucible at each position point after drawing of the current furnace based on the deformation coefficient of the quartz crucible and graphite crucible at each position point and the inner radius of the quartz crucible at each position point before drawing of the current furnace.
[0070] In one example, the graphite crucible will continue to age during its service life, resulting in different deformation coefficients of the quartz crucible and graphite crucible at various positions in different furnaces. The deformation coefficients of the quartz crucible and graphite crucible used to calculate the inner radius of the quartz crucible at various positions after drawing of the current furnace in this application are based on the inner radius of the quartz crucible and graphite crucible at various positions before and after drawing of the previous furnace, which can obtain a more accurate inner radius of the quartz crucible at various positions after drawing of the current furnace.
[0071] In an example, the inner radius of the quartz crucible at each position point after pulling of the current furnace refers to the inner radius of the quartz crucible after the polycrystalline silicon material of the current furnace is melted into melt. The inner radius of the quartz crucible at each position point after pulling is the actual inner radius of the quartz crucible at each position point during the crystal pulling process. The actual inner radius of the quartz crucible at each position point cannot be measured during the crystal pulling process. The present application calculates the actual inner radius of the quartz crucible at each position point during the crystal pulling process based on the deformation coefficient of the quartz crucible and the graphite crucible, so that the accurate ratio of the crucible lifting rate and crystal growth rate at each position point can be calculated based on the actual inner radius of the quartz crucible at each position point, that is, the ratio of the quartz crucible lifting rate and crystal growth rate can be corrected based on the deformation coefficient of the quartz crucible and the graphite crucible, so as to accurately control the liquid mouth distance, and then obtain a stable temperature gradient at the interface of the growing crystal, and achieve the growth of low-defect crystals.
[0072] In one example, the inner radius of the quartz crucible at each position point after the current furnace is pulled is obtained by the following formula based on the deformation coefficient of the quartz crucible and the graphite crucible at each position point and the inner radius of the quartz crucible at each position point before the current furnace is pulled:
[0073] r′1_q=(1-kh)*r1_q
[0074] Among them, r′1_q represents the inner radius of the quartz crucible at each position point after drawing of the current furnace, k represents the deformation coefficient of the quartz crucible at each position point, h represents the deformation coefficient of the graphite crucible at each position point, and r1_q represents the inner radius of the quartz crucible at each position point before drawing of the current furnace.
[0075] In one example, the present application takes into account the influence of the deformation of the quartz crucible and the aging of the graphite crucible on the inner radius of the quartz crucible, and calculates the inner radius of the quartz crucible at each position point after drawing of the current furnace based on the deformation coefficient of the quartz crucible and the graphite crucible at each position point and the inner radius of the quartz crucible at each position point before drawing of the current furnace, and the calculation result is more accurate.
[0076] Finally, step S4 is performed to obtain the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the molten liquid of the current furnace is at each position point based on the inner radius of the quartz crucible at each position point after pulling of the current furnace.
[0077] Specifically, based on the inner radius of the quartz crucible at each position point after pulling of the current furnace, the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the melt of the current furnace is at each position point is obtained, including: obtaining the density of the melt and the density of the crystal of the current furnace, and measuring the inner radius of the crystal when the liquid level of the melt of the current furnace is at each position point; based on the density of the melt of the current furnace, the density of the crystal, the inner radius of the crystal when the liquid level of the melt is at each position point, and the inner radius of the quartz crucible at each position point after pulling, the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the melt of the current furnace is at each position point is obtained.
[0078] In one example, a CCD camera may be used to measure the inner radius of the crystal when the liquid level of the current heat is at various positions. Exemplarily, the density of the current heat's melt and the density of the crystal are constant.
[0079] In one example, the following formula is used to obtain the ratio of the lifting rate of the quartz crucible to the crystal growth rate when the liquid level of the current furnace is at each position point based on the density of the melt of the current furnace, the density of the crystal, the inner radius of the crystal when the liquid level of the melt is at each position point, and the inner radius of the quartz crucible at each position point after pulling:
[0080]
[0081] Among them, CLR represents the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the current furnace is at each position point, ρ s Indicates the density of the melt in the current heat, ρ L Indicates the density of the crystal in the current batch, r CRY represents the inner radius of the crystal when the liquid level of the melt of the current heat is at each position point, and r′1_q represents the inner radius of the quartz crucible at each position point after pulling of the current heat.
[0082] In one example, since the present application can calculate the inner radius of the quartz crucible at each position point after pulling of the current furnace, the above formula can be used to calculate the accurate ratio of the quartz crucible lifting rate and crystal growth rate when the liquid level of the melt of the current furnace is at each position point, thereby being able to accurately control the liquid mouth distance, and then obtain a stable temperature gradient at the interface of the growing crystal, thereby achieving the growth of low-defect crystals.
[0083] In one example, as a combination of the above embodiments, the calculation process of the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the second and third heats of the melt in the graphite crucible service life is at various positions is described in detail:
[0084] In the second heat, the inner radius of the quartz crucible and the graphite crucible at each position point before and after drawing of the first heat has been measured, and the deformation coefficient of the quartz crucible and the graphite crucible at each position point is obtained based on the inner radius of the quartz crucible and the graphite crucible at each position point before and after drawing of the first heat; then, based on the deformation coefficient of the quartz crucible and the graphite crucible and the measured inner radius of the quartz crucible at each position point before drawing of the second heat, the inner radius of the quartz crucible at each position point after drawing of the second heat is obtained; then, based on the inner radius of the quartz crucible at each position point after drawing of the second heat, the density of the melt, the density of the crystal and the inner radius of the crystal when the liquid level of the melt is at each position point, the ratio of the quartz crucible lifting rate and the crystal growth rate when the liquid level of the melt in the second heat is at each position point is obtained.
[0085] In the third heat, based on the measured inner radius of the quartz crucible at each position point before drawing in the second heat and the calculated inner radius of the quartz crucible at each position point after drawing in the second heat, the deformation coefficient of the quartz crucible at each position point is obtained. At the same time, the inner radius of the graphite crucible at each position point after drawing in the first heat is the inner radius of the graphite crucible at each position point before drawing in the second heat, and the inner radius of the graphite crucible at each position point after drawing in the second heat is also measured. Based on the measured inner radius of the graphite crucible at each position point before and after drawing in the second heat, the deformation coefficient of the quartz crucible at each position point is obtained. radius, and obtain the deformation coefficient of the graphite crucible at each position point; then, based on the deformation coefficients of the quartz crucible and the graphite crucible and the measured inner radius of the quartz crucible at each position point before drawing of the third furnace, obtain the inner radius of the quartz crucible at each position point after drawing of the third furnace; then, based on the inner radius of the quartz crucible at each position point after drawing of the third furnace, the density of the melt, the density of the crystal and the inner radius of the crystal when the liquid level of the melt is at each position point, obtain the ratio of the quartz crucible lifting rate and the crystal growth rate when the liquid level of the melt in the third furnace is at each position point.
[0086] In an exemplary embodiment, for the calculation process of the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the melt in the furnace after the third furnace within the use cycle of the graphite crucible is at various position points, the calculation process of the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the melt in the third furnace is at various position points can be referred to, and no further details are given here.
[0087] In one example, if Figure 4As shown, the preset ratio of the quartz crucible lifting rate to the crystal growth rate obtained by the method of the present application is basically the same as the measured ratio of the quartz crucible lifting rate to the crystal growth rate, that is, the method of the present application can obtain an accurate ratio of the quartz crucible lifting rate to the crystal growth rate; wherein CLR represents the ratio of the quartz crucible lifting rate to the crystal growth rate, crystal length represents the crystal length, the crystal length corresponds to the liquid level position of the melt, and the liquid level of the melt decreases as the crystal length increases.
[0088] In one example, the low-defect crystal referred to in this application refers to a crystal with a COP free yield greater than 93% detected by testing equipment such as copper rust, SPx, etc. Exemplarily, the method of this application can be used to grow a crystal with a COP free yield of 96.8%.
[0089] In one example, the present application provides defect detection results of a comparative crystal and an example crystal, wherein the comparative crystal is a crystal grown by a method in the related art (i.e., during the growth process, the ratio of the quartz crucible lifting rate to the crystal growth rate is not corrected). For example, during the growth process of the comparative crystal, the ratio of the quartz crucible lifting rate to the crystal growth rate is set to be Figure 2 The ratio of the quartz crucible lifting rate to the crystal growth rate is preset in the comparative example; the example crystal is a crystal obtained by the method for growing low-defect crystals of the present application. Figure 5 As shown, defect detection was performed on the example crystal and the comparative example crystal. Compared with the comparative example crystal, the qualified zone length in the example crystal was significantly longer and the high defect zone length was significantly shorter, wherein the qualified zone refers to the area in the crystal that meets the low defect crystal conditions, and the high defect zone refers to the area in the crystal that does not meet the low defect crystal conditions. That is, the effective length (i.e., qualified zone length) of the low-defect crystal obtained by the method for growing low-defect crystals of the present application is significantly longer, and the stability is significantly improved. Exemplarily, the high defect zone of the head and tail sections of the crystal is the transition zone between the head and tail of the crystal, which has nothing to do with the control of the ratio of the quartz crucible lifting rate to the crystal growth rate.
[0090] So far, the description of the key steps of the method for growing low-defect crystals of the present application has been completed. The complete method for growing low-defect crystals may also include other steps, which will not be described one by one here. It is worth mentioning that the order of the above steps can be adjusted without conflict.
[0091] In summary, the method for growing low-defect crystals in the embodiment of the present application obtains the deformation coefficients of the quartz crucible and the graphite crucible, and corrects the ratio of the quartz crucible lifting rate to the crystal growth rate based on the deformation coefficients of the quartz crucible and the graphite crucible. The accurate ratio of the quartz crucible lifting rate to the crystal growth rate can be obtained, so that the liquid mouth distance can be accurately controlled, and then a stable temperature gradient of the growing crystal interface can be obtained, thereby achieving the growth of low-defect crystals.
[0092] Although multiple embodiments are described herein, it should be understood that a variety of other modifications and embodiments may be conceived by those skilled in the art, all of which will fall within the spirit and scope of the concepts disclosed herein. More particularly, various modifications and changes may be made to the arrangements and / or components of the combined arrangements of the subject matter within the scope of the disclosure, drawings, and appended claims of the present application. In addition to modifications and changes to the components and / or arrangements, the use of alternatives is also an obvious option for those skilled in the art.
Claims
1. A method for growing a low-defect crystal, characterized in that: The method comprises: Obtaining deformation coefficients of the quartz crucible and the graphite crucible at a plurality of positions from an initial liquid level position to an end liquid level position of the molten liquid contained in the quartz crucible; Measuring the inner radius of the quartz crucible at each of the position points before drawing of the current furnace; Based on the deformation coefficients of the quartz crucible and the graphite crucible at each of the positions and the inner radius of the quartz crucible at each of the positions before drawing of the current furnace, the inner radius of the quartz crucible at each of the positions after drawing of the current furnace is obtained; Based on the inner radius of the quartz crucible at each of the positions after pulling of the current furnace, the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the molten liquid of the current furnace is at each of the positions is obtained.
2. The method according to claim 1, characterized in that Obtaining deformation coefficients of the quartz crucible and the graphite crucible at multiple positions from an initial liquid level position to an end liquid level position of the molten liquid contained in the quartz crucible, including: The first heat in the life cycle of the graphite crucible: Respectively measuring the inner radius of the quartz crucible and the graphite crucible at each of the position points before and after drawing; The remaining heats in the life cycle of the graphite crucible are: The deformation coefficients of the quartz crucible and the graphite crucible at each of the positions are obtained based on the inner radii of the quartz crucible and the graphite crucible at each of the positions before and after drawing in the previous heat.
3. The method according to claim 2, characterized in that The remaining furnaces within the use cycle of the graphite crucible also include a step of measuring the inner radius of the graphite crucible at each of the position points after drawing in the current furnace.
4. The method according to claim 1, characterized in that: Based on the inner radius of the quartz crucible at each of the position points after pulling of the current furnace, the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the molten liquid of the current furnace is at each of the position points is obtained, including: Obtaining the density of the melt and the density of the crystal of the current heat, and measuring the inner radius of the crystal when the liquid level of the melt of the current heat is at each of the position points; Based on the density of the melt in the current furnace, the density of the crystal, the inner radius of the crystal when the liquid level of the melt is at each of the position points, and the inner radius of the quartz crucible at each of the position points after pulling, the ratio of the quartz crucible lifting rate and the crystal growth rate when the liquid level of the melt in the current furnace is at each of the position points is obtained.
5. The method according to claim 4, characterized in that The ratio of the lifting rate of the quartz crucible to the crystal growth rate when the liquid level of the current furnace is at each of the positions is obtained by the following formula based on the density of the melt of the current furnace, the density of the crystal, the inner radius of the crystal when the liquid level of the melt is at each of the positions, and the inner radius of the quartz crucible at each of the positions after pulling: Wherein, CLR represents the ratio of the quartz crucible lifting rate to the crystal growth rate when the liquid level of the melt of the current furnace is at each of the positions, ρ s represents the density of the melt in the current heat, ρ L Indicates the density of the crystal in the current batch, r CRY represents the inner radius of the crystal when the liquid level of the melt in the current furnace is at each of the position points, and r′1_q represents the inner radius of the quartz crucible at each of the position points after pulling in the current furnace.
6. The method according to claim 1, characterized in that The inner radius of the quartz crucible at each of the positions after drawing in the current furnace is obtained by the following formula based on the deformation coefficients of the quartz crucible and the graphite crucible at each of the positions and the inner radius of the quartz crucible at each of the positions before drawing in the current furnace: r′1_q=(1-kh)*r1_q Among them, r′1_q represents the inner radius of the quartz crucible at each of the said position points after drawing of the current furnace, k represents the deformation coefficient of the quartz crucible at each of the said position points, h represents the deformation coefficient of the graphite crucible at each of the said position points, and r1_q represents the inner radius of the quartz crucible at each of the said position points before drawing of the current furnace.
7. The method according to claim 2, characterized in that: The deformation coefficients of the quartz crucible and the graphite crucible at each of the positions are obtained by the following formulas based on the inner radius of the quartz crucible and the graphite crucible at each of the positions before and after drawing in the previous heat: Wherein, k represents the deformation coefficient of the quartz crucible at each of the positions, h represents the deformation coefficient of the graphite crucible at each of the positions, r0_q and r0 ′ _q respectively represent the inner radius of the quartz crucible at each position before and after the previous heat, r0_g and r0 ′ _g respectively represent the inner radius of the graphite crucible at each of the position points before and after drawing of the previous heat.
8. The method according to claim 3, characterized in that A laser diameter gauge is used to measure the inner radius of the quartz crucible and the graphite crucible at each of the positions before and after drawing of the first furnace, the inner radius of the quartz crucible at each of the positions before drawing of the remaining furnaces, and the inner radius of the graphite crucible at each of the positions after drawing of the remaining furnaces.
9. The method according to claim 4, characterized in that A CCD camera is used to measure the inner radius of the crystal when the liquid level of the molten liquid of the current furnace is at each of the position points.
10. The method according to claim 2, characterized in that The number of furnaces in the use cycle of the graphite crucible is greater than or equal to 40 and less than or equal to 100.