CN113122910A - Single crystal furnace thermal field device, single crystal furnace and single crystal growth control method - Google Patents
Single crystal furnace thermal field device, single crystal furnace and single crystal growth control method Download PDFInfo
- Publication number
- CN113122910A CN113122910A CN202010043383.6A CN202010043383A CN113122910A CN 113122910 A CN113122910 A CN 113122910A CN 202010043383 A CN202010043383 A CN 202010043383A CN 113122910 A CN113122910 A CN 113122910A
- Authority
- CN
- China
- Prior art keywords
- single crystal
- heat
- thermal field
- crystal furnace
- heat exchange
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
- C30B15/20—Controlling or regulating
- C30B15/203—Controlling or regulating the relationship of pull rate (v) to axial thermal gradient (G)
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/06—Silicon
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention discloses a thermal field device of a single crystal furnace, the single crystal furnace and a single crystal growth control method. The thermal field device of the single crystal furnace comprises: a heat shield having an air flow passage formed at a center thereof; the heat exchange component is arranged in the airflow channel and forms a lifting channel in a surrounding manner; the heat shield is arranged above the crucible; the heat shield has a bottom that is at least partially blocked between the heat exchange member and the level of silicon melt within the crucible. The single crystal furnace thermal field device is provided with a heat exchange component in an airflow channel formed by a heat shield, so that latent heat released by crystallization can be quickly taken away; the bottom of the heat shield is at least partially blocked between the heat exchange component and the liquid level of the silicon melt, so that the efficiency of the heat shield is improved; the longitudinal temperature gradient of the crystal is increased, and the growth speed of the crystal is improved.
Description
Technical Field
The invention belongs to the technical field of single crystal furnaces, and particularly relates to a single crystal furnace thermal field device, a single crystal furnace and a single crystal growth control method.
Background
With the arrival of the flat-price online era of the photovoltaic industry, the competition of the domestic crystal silicon industry is increasingly intensified, and the crystal silicon manufacturing industry mainly develops towards a large thermal field, large charging and large size at present, wherein the growth of monocrystalline silicon by the Czochralski method is the most widely applied technology for producing monocrystalline silicon at present.
When the monocrystal silicon is grown by the Czochralski method, a monocrystal furnace is one of core production equipment. Generally, a single crystal furnace includes a heater, a crucible, and a pulling head. Generally, a heater is disposed outside the crucible for heating the crucible, and the silicon material is heated and melted in the crucible to form a silicon melt. The pulling head immerses a seed crystal in the silicon melt, grows and pulls a single crystal rod below the seed crystal.
With the continuous development of the photovoltaic industry, how to reduce the cost on the premise of ensuring the quality becomes an important problem to be solved urgently. When the monocrystalline silicon is grown by the Czochralski method, the most direct mode for reducing the cost is to improve the production efficiency. The production efficiency is improved, and the crystal growth speed is preferably improved, so that the crystal pulling time is shortened.
The crystal growth rate provided by the existing single crystal furnace is low, and the crystal growth rate needs to be improved by modifying the single crystal furnace and improving the crystal pulling production process.
Disclosure of Invention
Aiming at the technical problems, the invention provides a thermal field device of a single crystal furnace, the single crystal furnace and a single crystal growth control method, and aims to solve the problem of low crystal growth speed in the prior art.
In a first aspect, the present invention provides a thermal field apparatus for a single crystal furnace, comprising:
a heat shield having an air flow passage formed at a center thereof;
the heat exchange component is arranged in the airflow channel and forms a lifting channel in a surrounding manner;
the heat shield is arranged above the crucible;
the heat shield has a bottom that is at least partially blocked between the heat exchange member and the level of silicon melt within the crucible.
Furthermore, the thermal field device of the single crystal furnace,
the bottom part is provided with an isolation surface at one side facing to the liquid level of the silicon melt;
the distance between the isolation surface and the liquid level of the silicon melt is 10-60 mm.
Further, the thermal field device of the single crystal furnace further comprises:
a heat collector;
the heat collecting bodies are arranged in groups on the heat exchange component;
the heat collecting body is positioned on one side of the heat exchange component facing the pulling channel.
Furthermore, the thermal field device of the single crystal furnace,
the heat collecting body comprises a convex part;
the convex part extends out from the heat exchange part towards the pulling channel.
Furthermore, the thermal field device of the single crystal furnace,
the heat collecting body and the heat exchange component are integrally processed; or
The heat collecting body is welded on the heat exchange component; or
The heat collecting body is connected with the heat exchange component in a threaded mode.
Furthermore, the thermal field device of the single crystal furnace,
the heat exchange component comprises a first shape outline and a second shape outline which are connected from top to bottom;
the first shape profile is a hollow truncated conical cylinder;
the second shape profile is a hollow cylindrical barrel;
the first shape contour is closed from top to bottom;
the inner diameter of the lower end of the first shape profile is equal to the inner diameter of the second shape profile.
Furthermore, the thermal field device of the single crystal furnace,
the heat shield includes an inner wall;
the inner wall comprises a second inner wall contour and a third inner wall contour which are connected from top to bottom;
the second inner wall profile is a truncated cone;
the third inner wall is cylindrical in profile;
the second inner wall profile is closed from top to bottom;
the inner diameter of the lower end of the second inner wall profile is equal to the inner diameter of the third inner wall profile.
Furthermore, the thermal field device of the single crystal furnace,
the inner wall further comprises a first inner wall profile connected above the second inner wall profile;
the first inner wall is cylindrical in profile;
the inner diameter of the upper end of the second inner wall profile is equal to the inner diameter of the first inner wall profile.
Further, the thermal field device of the single crystal furnace further comprises:
a cooling medium input line;
a cooling medium output line;
a flow channel for circulating a cooling medium is arranged in the heat exchange component;
the cooling medium flowing into the flow passage of the heat exchange member is conveyed by the cooling medium input pipe 1041;
the cooling medium flowing out of the flow channels of the heat exchange member is sent by the cooling medium output pipe 1042.
In a second aspect, the present invention provides a single crystal furnace comprising:
a crucible;
the heater is arranged on the outer side of the crucible and used for heating the crucible;
the thermal field apparatus for a single crystal furnace described in the first aspect,
the heat shield of the single crystal furnace thermal field device is arranged above the crucible.
In a third aspect, the present invention provides a single crystal growth control method applied to the single crystal furnace described in the second aspect, comprising:
step S1, acquiring a predetermined maximum pull rate V1M at each single crystal growth stage;
step S2, determining a preset pull rate V1P according to a pre-stored speed difference threshold value V1T;
step S3, according to the difference value between the actual pulling speed measured at the appointed first control time and the preset pulling speed V1P, adjusting the heating power of a heater and/or adjusting the distance between the separation surface at the bottom of the heat shield and the liquid level of the silicon melt and/or adjusting the flow rate of a cooling medium in a flow channel of the heat exchange part, so that the actual pulling speed measured at the appointed second control time is matched with the preset pulling speed V1P;
wherein, the growth stages of the single crystal are a seeding stage, a shouldering stage and a shouldering stage in sequence.
According to the single crystal furnace thermal field device and the single crystal furnace, the heat exchange component is arranged in the airflow channel formed by the heat shield, so that latent heat released by crystallization is quickly taken away, and the longitudinal temperature gradient of crystals is increased, so that the growth speed of the crystals is increased; the bottom of the heat shield at least partially blocks the space between the heat exchange component and the liquid level of the silicon melt to isolate the heat from the liquid level of the silicon melt, so that the heat exchange component can absorb more heat around the crystal bar, namely, the heat insulation area of the heat shield above the liquid level of the silicon melt in the crucible is increased, the efficiency of the heat shield is improved, the longitudinal temperature gradient of the crystal is increased, and the growth speed of the crystal is increased.
The single crystal growth control method provided by the invention is applied to the thermal field device and the single crystal furnace, the temperature and the thermal field in the single crystal furnace are changed by changing the power, and the latent heat released from a growth interface is absorbed by adjusting the distance between the separation surface at the bottom of the heat shield and the liquid level of the silicon melt and/or adjusting the flow velocity of a cooling medium in the flow channel of the heat exchange part, so that the longitudinal temperature gradient of the single crystal is increased, the fluctuation of the actual crystal pulling speed in a specified range of the preset crystal pulling speed is controlled, and the stable growth of the crystal is ensured while the crystal pulling speed is improved.
Drawings
The invention will be further described with reference to the accompanying drawings in which:
FIG. 1 is a schematic structural diagram of a thermal field device of a single crystal furnace according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a thermal field apparatus of a single crystal furnace according to another embodiment of the present invention;
FIG. 3 is a schematic diagram of a cross-section of a heat collector of a thermal field apparatus of a single crystal furnace according to an embodiment of the present invention;
FIG. 4 is another schematic cross-sectional view of a heat collector of a thermal field apparatus of a single crystal furnace in accordance with an embodiment of the present invention;
FIG. 5 is a graph showing a comparison of an actual pull rate, a predetermined pull rate and a maximum pull rate in the single crystal growth control method according to the embodiment of the present invention; wherein the content of the first and second substances,
1010: heat shielding; 1020: a heat exchange member; 1010A: an isolation surface; 1030: a heat collector; 1011: a first surface; 1012: a second surface; 1041: a cooling medium input line; 1042: a cooling medium output line; 2: a silicon rod; 2000: a crucible; 2010: melt level; 3010: a maximum pull rate; 3020: presetting a crystal pulling speed; 3030: the actual pull rate.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
In the technical field of growing monocrystalline silicon by the Czochralski method, the crystal growth speed and the crystal pulling speed have similar or same meanings; the growth interface has a similar or identical meaning as the crystalline interface.
As shown in fig. 1, the thermal field apparatus of a single crystal furnace according to an embodiment of the present invention includes:
a heat shield 1010 having an air flow channel formed at a center of the heat shield 1010;
the heat exchange part 1020 is arranged in the gas flow channel and forms a lifting channel in a surrounding manner;
the heat shield 1010 is arranged above the crucible 2000;
the heat shield 1010 has a bottom that is at least partially blocked between the heat exchange member 1020 and a silicon melt level 2010 within the crucible 2000.
According to the thermal field device of the single crystal furnace, the heat exchange component is arranged in the airflow channel formed by the heat shield, and latent heat released by crystallization is quickly taken away, so that the longitudinal temperature gradient of the crystal is increased in the thermal field of the pulling channel, and the growth speed of the crystal is increased.
In the thermal field device of the single crystal furnace of the embodiment, the heat shield is internally provided with the heat preservation felt which is used for isolating heat from the periphery of the heat shield (such as the liquid level of silicon melt, the thermal field outside the single crystal furnace and the like). When the bottom of the heat shield at least partially blocks the space between the heat exchange component and the liquid level of the silicon melt, the bottom of the heat shield can isolate the heat from the liquid level of the silicon melt, so that the heat exchange component can absorb more heat around the crystal bar, namely, the heat insulation area of the heat shield above the liquid level of the silicon melt in the crucible is increased, the efficiency of the heat shield is improved, the longitudinal temperature gradient of the crystal is increased, and the crystal pulling speed is increased.
In another aspect, the heat shield is used to direct a flow of shielding gas (e.g., argon).
Compared with the heat shield with only upright side walls in the prior art, the heat shield of the single crystal furnace thermal field device of the embodiment has the advantages that the bottom of the heat shield is at least partially blocked between the heat exchange part and the liquid level of the silicon melt, the heat shield area of the heat shield above the liquid level of the silicon melt in the crucible is increased, the efficiency of the heat shield is improved, the longitudinal temperature gradient of the crystal is increased, and the pulling speed is increased.
To further increase the effectiveness of the heat shield, the bottom of the single crystal furnace thermal field apparatus of this embodiment has a separation surface 1010A on the side facing the silicon melt level 2010;
the distance between the isolation surface 1010A and the liquid level 2010 of the silicon melt is 10-60 mm.
In the thermal field device of the single crystal furnace of the embodiment, the bottom of the heat shield is provided with the isolation surface at one side facing the liquid level of the silicon melt, so that the distance between the heat shield and the liquid level can be reduced, the heat exchange component can be closer to a growth interface, latent heat released by the silicon melt during crystallization can be absorbed as much as possible, the longitudinal temperature gradient of the crystal is increased, and the pulling speed is increased.
Preferably, the distance between the isolation surface 1010A and the liquid level 2010 of the silicon melt is 10-60 mm.
Preferably, the distance between the isolation surface 1010A and the liquid level 2010 of the silicon melt is 10 mm.
In particular, the isolation surface is approximately horizontal, i.e. approximately parallel to the silicon melt level.
It should be understood that the smaller the distance between the bottom of the heat shield and the melt level, the smaller the distance between the heat exchange member disposed within the heat shield and the growth interface; the closer the heat exchange part is to the growth interface, the more heat the heat exchange part absorbs, so that the heat exchange part can absorb more temperature of the growth interface, the longitudinal temperature gradient of the crystal is increased, and the crystal pulling speed is finally improved.
Further, in the thermal field apparatus of the single crystal furnace of the embodiment, the heat exchanging member 1020 is disposed on the side wall of the heat shield 1010.
Further, the thermal field apparatus of the single crystal furnace of this embodiment further includes:
a heat collector 1030;
the heat collecting bodies 1030 are disposed in groups at the heat exchanging part 1020;
the heat collecting body 1030 is located at a side of the heat exchanging member 1020 facing the pull-up passage.
In the thermal field device of the single crystal furnace of the embodiment, the heat collectors are arranged in groups on one side of the heat exchange component facing the pulling channel, so that more heat is collected from the pulling channel, the heat is guided out of the single crystal furnace by the heat exchange component, the longitudinal temperature gradient of the crystal is increased, and the pulling speed is improved.
Further, in the thermal field apparatus of the single crystal furnace of this embodiment,
the heat collector 1030 includes a protrusion;
the protrusion extends from the heat exchange member 1020 toward the drawing channel.
The thermal field device of the single crystal furnace of this embodiment further increases the contact area with the thermal field along the convex portion projecting in the direction toward the pulling path, thereby collecting more heat from within the pulling path and guiding the heat outside the single crystal furnace by the heat exchanging member to increase the longitudinal temperature gradient of the crystal and increase the pulling speed.
The raised portion may be a single body, which may be a triangular prism, a polygonal prism, or a tilted fin. At this time, a plurality of single protrusions are dispersedly disposed on a side of the heat exchange member 1020 facing the pull-up channel.
Preferably, the extending locus of the convex portion of each group of the heat collectors may extend along the central axis X of the heat shield 1010 or along a direction perpendicular to the central axis X of the heat shield 1010.
When the projection is in the shape of a continuously extending bar, the cross section thereof may be any of a triangle, a trapezoid, and a rectangle. A partial cross-sectional expanded view of a plurality of sets of parallel arranged bar-like projections is shown in fig. 3 or fig. 4.
It should be understood that, in practical use, the heat collecting body may have a cross-sectional shape of a convex surface, which is a rectangle, a hemisphere, an Ω -shape, or an S-shape, and other shapes that can be continuously arranged and have an arrangement structure that can increase the heat exchange surface area.
It should be understood that, in practical use, the convex portion of the heat collector may further have a plurality of surfaces that are concave, thereby further increasing the heat exchange area of the heat collector.
Further, in order to reduce the difficulty of production and manufacturing and further reduce the purchase and maintenance cost of the single crystal furnace, the heat collection body 1030 and the heat exchange component 1020 of the single crystal furnace thermal field device are integrally processed; or the heat collecting body 1030 is welded to the heat exchanging member 1020; or the heat collecting body 1030 is screw-coupled to the heat exchanging member 1020.
In order to further increase the surface available for heat exchange and increase the heat exchange speed, in the thermal field device of the single crystal furnace of the embodiment,
the heat exchange part 1020 includes a first shape profile and a second shape profile connected from top to bottom;
the first shape outline is a hollow truncated cone-shaped cylinder;
the second shape profile is a hollow cylindrical cylinder;
the first shape contour is closed from top to bottom;
the inner diameter of the lower end of the first shape profile is equal to the inner diameter of the second shape profile.
In the thermal field device of the single crystal furnace according to the embodiment, as a whole, the upper portion of the heat exchange member is a hollow inverted circular truncated cone (large in the upper portion and small in the lower portion), and the lower portion thereof is a hollow cylinder. When the heat exchange component is regarded as an annular structural member with equal wall thickness or variable wall thickness, the heat exchange component is formed by connecting a first shape outline and a second shape outline from top to bottom; the first shape profile is a hollow truncated conical cylinder, and the second shape profile is a hollow cylindrical cylinder; the first shape wheel is closed up from top to bottom, and the inner diameter of the lower end of the first shape profile is equal to that of the second shape profile.
In the thermal field device of the single crystal furnace of the embodiment, the heat exchange component with the optimized shape has more surfaces for heat exchange, and a more optimized thermal field is formed in the pulling channel by quickly absorbing heat released by crystallization, so that the longitudinal temperature gradient of the crystal is increased, and the growth speed of the crystal is finally improved.
Specifically, by increasing the heat exchange surface, the heat absorption amplitude of the heat exchange component is increased, and the heat exchange component with the optimized shape can absorb more heat from the growth interface in unit time.
It should be noted that the term "truncated cone" as used herein refers to a partial cone or conical surface obtained by transversely cutting a complete cone or conical surface from a side near its vertex, wherein one end of the partial cone or conical surface has a size larger than that of the other end (e.g., larger in the top and smaller in the bottom) or one end of the partial cone or conical surface has a size smaller than that of the other end (e.g., smaller in the top and smaller in the bottom).
The "hollow truncated cone-shaped cylinder" herein has an outer contour which is a truncated cone and an inner contour which is also a truncated cone. Equal wall thickness if the distance between its outer contour and its inner contour is equal everywhere along its axial extension direction; a wall thickness is variable if the distance between its outer contour and its inner contour varies everywhere along its axial extension.
It should be noted that, the inner and outer contours of the heat exchange component are described above, the specific structure or components of the heat exchange component or the shapes of the inner and outer surfaces are not limited, and any heat exchange component satisfying the above contours has similar technical effects.
As an enclosure and an enclosed member, the surface profile of the inner wall of the heat shield 1010 is adapted to the shape profile of the heat exchanging member 1020 in order to increase the effect of the heat shield guiding the air flow. Accordingly, in the thermal field device of the single crystal furnace of this embodiment,
the inner wall 1011 includes a second inner wall profile and a third inner wall profile connected from top to bottom;
the profile of the second inner wall is truncated cone;
the profile of the third inner wall is cylindrical;
the second inner wall profile is closed from top to bottom;
the inner diameter of the lower end of the second inner wall profile is equal to the inner diameter of the third inner wall profile.
In the thermal field apparatus of the single crystal furnace of this embodiment, as a whole, the upper portion of the inner wall of the heat shield is constrained to a truncated cone (large in the upper portion and small in the lower portion) space, and the lower portion of the inner wall of the heat shield is constrained to a cylinder space. Specifically, the inner wall 1011 of the heat shield has a surface profile formed by connecting a second inner wall profile and a third inner wall profile from top to bottom; wherein, the second inner wall profile is a truncated conical surface (or an inverted round table surface), and the third inner wall profile is a cylindrical surface; the second inner wall profile is closed from top to bottom, and the inner diameter of the lower end of the second inner wall profile is equal to that of the third inner wall profile.
In the thermal field device of the single crystal furnace of the embodiment, after the shape of the inner wall is optimized, the heat shield has more surfaces for heat insulation, so that a more optimized thermal field is formed in the pulling channel, the longitudinal temperature gradient of the crystal is increased, and the crystal growth speed is finally improved.
It should be noted that the term "truncated cone" as used herein refers to a partial cone or conical surface obtained by transversely cutting a complete cone or conical surface from a side near its vertex, wherein one end of the partial cone or conical surface has a size larger than that of the other end (e.g., larger in the top and smaller in the bottom) or one end of the partial cone or conical surface has a size smaller than that of the other end (e.g., smaller in the top and smaller in the bottom).
It should be noted that, the surface profile of the inner wall of the heat shield is described above, the specific structure, components or shape of the inner wall of the heat shield is not limited, and any inner wall of the heat shield satisfying the above surface profile has similar technical effects.
In order to further optimize the thermal field in the pulling channel, the thermal field device of the single crystal furnace of the embodiment,
the inner wall 1011 further comprises a first inner wall profile connected above a second inner wall profile;
the first inner wall is cylindrical in profile;
the inner diameter of the upper end of the second inner wall profile is equal to the inner diameter of the first inner wall profile.
In the thermal field apparatus for a single crystal furnace of this embodiment, as a whole, the inner wall of the heat shield is confined at the uppermost portion to a cylindrical space. Specifically, the inner wall 1011 of the heat shield has a surface profile formed by connecting a first inner wall profile, a second inner wall profile and a third inner wall profile from top to bottom; the first inner wall profile is a cylindrical surface, the second inner wall profile is a truncated conical surface (or an inverted circular table surface), and the third inner wall profile is a cylindrical surface; the second inner wall profile is closed from top to bottom, and the lower end of the second inner wall profile is as large as the third inner wall profile; the inner diameter of the upper end of the second inner wall profile is equal to the inner diameter of the first inner wall profile.
The inner wall of the single crystal furnace thermal field device has a three-section shape, and the heat shield with the optimized shape is arranged in the pulling channel, so that a more optimized thermal field is formed, the longitudinal temperature gradient of the crystal is increased, and the growth speed of the crystal is finally improved.
It should be noted that the term "truncated cone" as used herein refers to a partial cone or conical surface obtained by transversely cutting a complete cone or conical surface from a side near its vertex, wherein one end of the partial cone or conical surface has a size larger than that of the other end (e.g., larger in the top and smaller in the bottom) or one end of the partial cone or conical surface has a size smaller than that of the other end (e.g., smaller in the top and smaller in the bottom).
It should be noted that, the surface profile of the inner wall of the heat shield is described above, the specific structure, components or shape of the inner wall of the heat shield is not limited, and any inner wall of the heat shield satisfying the above surface profile has similar technical effects.
Specifically, in the central axis direction of the heat shield 1010, the transverse distance between the inner wall of the heat shield 1010 closest to the heat exchange component and the outer wall of the heat exchange component 1020 is substantially kept unchanged, so that the airflow resistance in the airflow channel is reduced, and the airflow field is more stable.
Further, the thermal field apparatus of the single crystal furnace of this embodiment further includes:
a cooling medium input line 1041;
a cooling medium output pipe 1042;
a flow channel for circulating a cooling medium is arranged in the heat exchange part 1020;
the cooling medium flowing into the flow passage of the heat exchange member 1020 is delivered by the cooling medium input pipe 1041;
the cooling medium flowing out of the flow passage of the heat exchanging member 1020 is supplied through the cooling medium output pipe 1042.
The cooling medium in the flow channel arranged in the thermal field device of the single crystal furnace of the embodiment can quickly guide latent heat released during crystallization out of the furnace, and the cooling medium can take away heat, so that the longitudinal temperature gradient of the crystal is increased, and the growth speed of the single crystal is further improved.
Further, in the thermal field apparatus of a single crystal furnace of this embodiment, the cooling medium is any one of: liquid nitrogen, liquid argon and industrial water.
Preferably, the flow channel has a spiral ascending track or an end-to-end U-shaped track in the extending direction.
Preferably, the flow channel may have one set of tracks or a plurality of sets of tracks arranged in parallel and spaced apart around the heat exchange member.
By utilizing a fluid storage device (used for storing a cooling medium) and a liquid delivery device (such as a gear pump, a vane pump and other fluid pumps) provided in the prior art, the cooling medium circulates in a flow channel of a heat exchange part, so that heat exchange is realized, and latent heat released during the crystallization of the silicon melt is taken away.
At this time, the cooling medium input pipe 1041, the cooling medium output pipe 1042, the flow channel in the heat exchanging part 1020, the liquid delivery device (such as a gear pump, a fluid pump such as a vane pump, etc.), the fluid storage device (for storing the cooling medium, such as a liquid reservoir), and other accessories (such as a fluid pressure adjusting device and a fluid flow rate adjusting device) together form a circulating cooling system.
It should be understood that the longitudinal temperature gradient may be further adjusted by adjusting the flow rate of the cooling medium within the liquid flow channel (e.g., increasing or decreasing the volumetric flow rate of the cooling medium).
The thermal field device capable of increasing the temperature gradient is arranged above the crucible 2000, so that the modified single crystal furnace is obtained. The single crystal furnace can also increase the longitudinal temperature gradient in the crystal growth direction, thereby improving the crystal pulling speed.
As shown in FIG. 1, in the thermal field apparatus for a single crystal furnace according to the embodiment of the present invention, a heat shield 1010 is disposed above a crucible, and the heat shield 1010 includes a first surface 1011 near a silicon rod 2 and a second surface 1012 opposite to the first surface 1011. The first surface 1011 is closed about its central axis forming an air flow channel. The second surface 1012 is an outer wall of the heat shield. Between the first surface 1011 and the second surface 1012, a thermal insulating material, such as a thermal blanket, is disposed.
The heat shield forms an air flow circulation in the single crystal furnace, controls the temperature gradient of the thermal field around the silicon rod 2, and isolates the silicon rod 2 from the high temperature zone on the heater side.
Preferably, the heat exchanging member 1020 is an axisymmetric structure formed around the central axis X of the heat shield, and includes an annular side wall and a hollow annular bottom, and the longitudinal section of the heat exchanging member is L-shaped; preferably, a flow channel through which a cooling medium flows is also provided at the bottom thereof.
Preferably, the heat exchange member is contoured to form a cylinder open at both ends in the space, and the cylinder is formed by one or more of a hollow truncated conical cylinder, a hollow cylindrical cylinder, a hollow drum-shaped cylinder and a hollow polygonal cylinder in combination along the extending direction of the cylinder.
As shown in fig. 1, a plurality of sets of outwardly convex heat collecting bodies are disposed on one side of the heat exchanging member 1020 close to the silicon rod 2, the plurality of sets of heat collecting bodies are uniformly spaced, and a contact point or a connection point thereof with the heat exchanging member 1020 is located on one circumferential surface coaxial with the silicon rod.
The raised heat collector has a plurality of outer surfaces, and compared with the arc profile surface of the heat exchange part, the contact area between the heat field around the silicon rod and the heat exchange part 1020 is increased, so that the heat transfer efficiency can be improved, the longitudinal temperature gradient is further increased, and the crystal pulling speed is further increased.
Preferably, the cooling medium is a gas or a liquid, such as liquid nitrogen, liquid argon, or cooling water. When in use, the material can be reasonably selected according to the requirements. Inert gas such as liquid nitrogen or liquid argon is used as a cooling medium, so that the heat capacity is large, and the production safety in a closed high-heat space can be improved. The thermal field apparatus of this example was cooled with liquid argon. The liquid argon is used as inert gas, so that the properties are stable, and the safety risk is low.
Preferably, the heat collector is integrally formed with the heat exchanging member. Preferably, the heat collecting bodies are arranged on the surface of the heat exchanging component facing the silicon rod at intervals by welding, pasting, adhering and the like.
The connection mode of the heat collecting body and the heat exchange component is convenient for processing or maintenance, and the purchase cost and the maintenance cost of the pulling equipment are directly reduced, so that the production cost of the czochralski silicon is further reduced.
Preferably, the heat exchange component and the heat collector are made of stainless steel materials, so that the heat dissipation effect is good, the corrosion is not easy, and the service life is long.
As shown in fig. 1, the profile of the heat exchange member 1020 is a hollow cylinder with an equal diameter; in this case, the contour of the first surface 1011 of the heat shield is adapted to the contour of the heat exchanging member 1020, the distance between which is approximately equal in the direction of the central axis of the silicon rod.
As shown in fig. 2, the profile of the heat exchange member 1020 is formed by connecting a truncated cone with a downward closing-in and a cylinder with an equal diameter; in this case, the contour of the first surface 1011 of the heat shield is adapted to the contour of the heat exchanging member 1020, the distance between which is approximately equal in the direction of the central axis of the silicon rod.
At this moment, the surface of the heat exchange component in the heat field has an inclined angle or an arc curve, so that the heat exchange area is further increased, and the heat exchange effect is better.
At this time, the inner surface of the heat shield facing to the pulling channel side has an inclined angle or an arc curve, so that the heat insulation area is further increased, and therefore, the heat insulation effect is better. At this time, the protruded heat collecting bodies are arranged at intervals in the circumferential direction of the variable diameter conical surface and the circumferential direction of the equal diameter cylindrical surface at the side facing the silicon rod in groups by means of welding, pasting, integral molding with the heat exchanging member, and the like. The heat exchange part faces to the surface of the silicon rod.
In summary, the thermal field device of the embodiment of the invention arranges the isolation surface at the bottom of the thermal shield, and the bottom of the thermal shield partially blocks between the heat exchange component and the liquid level of the silicon melt to isolate the heat from the liquid level of the silicon melt, so that the heat exchange component can absorb more heat around the crystal bar, that is, the thermal shield improves the efficiency of the thermal shield and increases the longitudinal temperature gradient of the crystal by increasing the heat insulation area of the thermal shield above the liquid level of the silicon melt in the crucible to improve the growth speed (or the crystal pulling speed) of the crystal; the bottom of the heat shield is provided with an isolation surface, so that the distance between the lower part of the heat shield and the surface of the silicon melt is smaller, and more latent heat released by the silicon melt during crystallization can be absorbed; the heat exchange part with the circulating cooling flow channel is arranged, and the heat collector is arranged on the other side of the heat exchange part opposite to the heat shield, so that the heat exchange area is further increased, the longitudinal temperature gradient of the crystal is effectively increased, and the crystal pulling speed and efficiency are improved.
On the other hand, the single crystal growth control method using the thermal field device and the single crystal furnace according to the embodiment of the invention includes:
step S1, acquiring a predetermined maximum pull rate V1M at each single crystal growth stage;
step S2, determining a preset pull rate V1P according to a pre-stored speed difference threshold value V1T;
step S3, according to the difference value between the actual pulling speed measured at the appointed first control time and the preset pulling speed V1P, adjusting the heating power of a heater and/or adjusting the distance between the separation surface at the bottom of the heat shield and the liquid level of the silicon melt and/or adjusting the flow rate of a cooling medium in a flow channel of the heat exchange part, so that the actual pulling speed measured at the appointed second control time is matched with the preset pulling speed V1P;
wherein, each single crystal growth stage is a seeding stage, a shouldering stage and a shouldering stage in turn.
In the method of this embodiment, the specified first control timing is earlier than the specified second control timing.
In the method of this embodiment, the predetermined maximum pull rate V1M can be obtained from a control parameter setting interface displayed in a display screen of the single crystal furnace;
in the method of this embodiment, the predetermined maximum pull rate V1M is determined by calculation based on the pull rate at which the crystal is deformed or distorted in each growth stage of the crystal.
Note that, the preset pull rate V1P in the step S2 is not greater than the maximum pull rate V1M; the difference between the preset pull rate V1P and the maximum pull rate V1M is not less than a predetermined and stored rate difference threshold V1T.
Fig. 5 shows the relative magnitude relationship between the maximum pull rate 3010, the preset pull rate 3020, and the actual pull rate 3030. As can be seen from FIG. 5, the predetermined pull rate is less than the maximum pull rate, and the actual pull rate fluctuates up and down around the predetermined pull rate.
Preferably, the maximum pull rate of the single crystal furnace using the thermal field device is 150mm/h, and the preset pull rate is set to 145 mm/h.
Since the temperature in the single crystal furnace is constantly changing, the actual pull rate in step S3 is also constantly changing.
The single crystal growth control method applied with the thermal field device and the single crystal furnace is applied to the thermal field device and the single crystal furnace, the temperature and the thermal field in the single crystal furnace are changed by changing the power of the heater, the heat absorbed from a growth interface is increased by adjusting the distance between the separation surface at the bottom of the heat shield and the liquid level of the silicon melt and/or adjusting the flow speed of a cooling medium in a flow channel of the heat exchange part, so that the longitudinal temperature gradient of the single crystal is increased, the fluctuation of the actual crystal pulling speed in a specified range of the preset crystal pulling speed is controlled, and the stable growth of the crystal is ensured while the crystal pulling speed is increased.
Specifically, the temperature and the thermal field in the single crystal furnace are changed by changing the power, including the temperature in the thermal field of the single crystal furnace is continuously changed by adjusting the heating power of the heater.
Specifically, increasing the amount of heat absorbed from the growth interface comprises:
adjusting the distance between an isolation surface at the bottom of the heat shield and the liquid level of the silicon melt; and/or
And adjusting the flow velocity of the cooling medium in the flow channel of the heat exchange part.
Specifically, in a control parameter setting interface displayed in a display screen of the single crystal furnace, the numerical values of the parameters are changed, so that the power is changed to change the temperature and the thermal field in the single crystal furnace; or increasing the heat absorbed from the growth interface, thereby changing the temperature and the thermal field distribution in the single crystal furnace, controlling the actual crystal pulling speed to fluctuate within the specified range of the preset crystal pulling speed, and ensuring the stable growth of the crystal while improving the crystal pulling speed.
The single crystal growth control method provided by the invention is applied to the thermal field device and the single crystal furnace, the temperature and the thermal field in the single crystal furnace are changed by changing the power, and the latent heat released from a growth interface is absorbed by adjusting the distance between the separation surface at the bottom of the heat shield and the liquid level of the silicon melt and/or adjusting the flow velocity of a cooling medium in the flow channel of the heat exchange part, so that the longitudinal temperature gradient of the single crystal is increased, the fluctuation of the actual crystal pulling speed in a specified range of the preset crystal pulling speed is controlled, and the stable growth of the crystal is ensured while the crystal pulling speed is improved.
The above embodiments are intended to illustrate that the present invention may be implemented or used by those skilled in the art, and modifications to the above embodiments will be apparent to those skilled in the art, and any method, process, product, which complies with the principles and novel and inventive features disclosed herein, which complies with the scope of the present invention, are intended to be within the scope of the present invention as defined by the claims and the description.
The invention has been described above by reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a// the [ device, component, etc ]" are to be interpreted openly as at least one instance of a device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (11)
1. A thermal field device of a single crystal furnace is characterized by comprising:
a heat shield (1010), the heat shield (1010) having an air flow channel formed at a center thereof;
the heat exchange component (1020) is arranged in the gas flow channel and forms a pulling channel in a surrounding manner;
the heat shield (1010) is arranged above the crucible (2000);
the heat shield (1010) has a bottom that is at least partially blocked between the heat exchange member (1020) and a silicon melt level (2010) within the crucible (2000).
2. The single crystal furnace thermal field apparatus of claim 1,
said bottom having an isolation surface (1010A) on a side facing said silicon melt level (2010);
the distance between the isolation surface (1010A) and the liquid level (2010) of the silicon melt is 10-60 mm.
3. The single crystal furnace thermal field apparatus of claim 1, further comprising:
a heat collector (1030);
the heat collecting bodies (1030) are arranged in groups on the heat exchanging component (1020);
the heat collecting body (1030) is located at a side of the heat exchanging member (1020) facing the pull-up passage.
4. The single crystal furnace thermal field apparatus according to claim 3,
said heat collector (1030) comprises a protrusion;
the convex part extends out from the heat exchange part (1020) to the direction of the pulling channel.
5. The single crystal furnace thermal field apparatus according to claim 3,
the heat collecting body (1030) and the heat exchange component (1020) are integrally processed; or
Said heat collecting body (1030) is welded to said heat exchanging member (1020);
or the heat collecting body (1030) is connected to the heat exchanging part (1020) in a threaded manner.
6. The single crystal furnace thermal field apparatus of claim 1,
the heat exchange component (1020) comprises a first shape profile and a second shape profile which are connected from top to bottom;
the first shape profile is a hollow truncated conical cylinder;
the second shape profile is a hollow cylindrical barrel;
the first shape contour is closed from top to bottom;
the inner diameter of the lower end of the first shape profile is equal to the inner diameter of the second shape profile.
7. The single crystal furnace thermal field apparatus of claim 1,
the heat shield (1010) includes an inner wall (1011);
the inner wall (1011) comprises a second inner wall profile and a third inner wall profile connected from top to bottom;
the second inner wall profile is a truncated cone;
the third inner wall is cylindrical in profile;
the second inner wall profile is closed from top to bottom;
the inner diameter of the lower end of the second inner wall profile is equal to the inner diameter of the third inner wall profile.
8. The single crystal furnace thermal field apparatus according to claim 7,
the inner wall (1011) further comprising a first inner wall profile connected above the second inner wall profile;
the first inner wall is cylindrical in profile;
the inner diameter of the upper end of the second inner wall profile is equal to the inner diameter of the first inner wall profile.
9. The single crystal furnace thermal field apparatus of claim 1, further comprising:
a cooling medium inlet line (1041);
a cooling medium output pipe (1042);
a flow channel for circulating a cooling medium is arranged in the heat exchange part (1020);
the cooling medium flowing into the flow channel of the heat exchange part (1020) is conveyed by the cooling medium input pipeline (1041);
the cooling medium flowing out of the flow channel of the heat exchange part (1020) is conveyed by the cooling medium output pipeline (1042).
10. A single crystal furnace, comprising:
a crucible (2000);
a heater disposed outside the crucible (2000) for heating the crucible (2000);
the single crystal furnace thermal field apparatus according to any one of claims 1 to 9,
the heat shield (1010) of the single crystal furnace thermal field device is arranged above the crucible (2000).
11. A single crystal growth control method applied to the single crystal furnace according to claim 10, comprising:
step S1, acquiring a predetermined maximum pull rate V1M at each single crystal growth stage;
step S2, determining a preset pull rate V1P according to a pre-stored speed difference threshold value V1T;
step S3, according to the difference value between the actual pulling speed measured at the appointed first control time and the preset pulling speed V1P, adjusting the heating power of a heater and/or adjusting the distance between the separation surface at the bottom of the heat shield and the liquid level of the silicon melt and/or adjusting the flow rate of a cooling medium in a flow channel of the heat exchange part, so that the actual pulling speed measured at the appointed second control time is matched with the preset pulling speed V1P;
wherein, the growth stages of the single crystal are a seeding stage, a shouldering stage and a shouldering stage in sequence.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010043383.6A CN113122910A (en) | 2020-01-15 | 2020-01-15 | Single crystal furnace thermal field device, single crystal furnace and single crystal growth control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010043383.6A CN113122910A (en) | 2020-01-15 | 2020-01-15 | Single crystal furnace thermal field device, single crystal furnace and single crystal growth control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113122910A true CN113122910A (en) | 2021-07-16 |
Family
ID=76772171
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010043383.6A Pending CN113122910A (en) | 2020-01-15 | 2020-01-15 | Single crystal furnace thermal field device, single crystal furnace and single crystal growth control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113122910A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114150371A (en) * | 2021-12-06 | 2022-03-08 | 徐州鑫晶半导体科技有限公司 | Cooling assembly, control method thereof and crystal growing device |
| CN114232079A (en) * | 2021-11-25 | 2022-03-25 | 华坪隆基硅材料有限公司 | Crystal pulling method and monocrystalline silicon wafer |
| WO2023179627A1 (en) * | 2022-03-21 | 2023-09-28 | 洛阳长缨新能源科技有限公司 | Crystal cooling apparatus for simultaneously drawing multiple crystals and artificial crystal preparation device |
| WO2024032332A1 (en) * | 2022-08-09 | 2024-02-15 | 隆基绿能科技股份有限公司 | Monocrystalline silicon rod drawing apparatus and method, heat exchanger, and heat exchange assembly |
-
2020
- 2020-01-15 CN CN202010043383.6A patent/CN113122910A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114232079A (en) * | 2021-11-25 | 2022-03-25 | 华坪隆基硅材料有限公司 | Crystal pulling method and monocrystalline silicon wafer |
| CN114150371A (en) * | 2021-12-06 | 2022-03-08 | 徐州鑫晶半导体科技有限公司 | Cooling assembly, control method thereof and crystal growing device |
| WO2023179627A1 (en) * | 2022-03-21 | 2023-09-28 | 洛阳长缨新能源科技有限公司 | Crystal cooling apparatus for simultaneously drawing multiple crystals and artificial crystal preparation device |
| WO2024032332A1 (en) * | 2022-08-09 | 2024-02-15 | 隆基绿能科技股份有限公司 | Monocrystalline silicon rod drawing apparatus and method, heat exchanger, and heat exchange assembly |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113122910A (en) | Single crystal furnace thermal field device, single crystal furnace and single crystal growth control method | |
| US20230095607A1 (en) | Heat exchange device and single crystal furnace | |
| CN211872142U (en) | Single crystal furnace thermal field device and single crystal furnace | |
| CN103911654B (en) | The method preparing the monocrystal silicon of a diameter of more than 400mm | |
| US5394825A (en) | Method and apparatus for growing shaped crystals | |
| CN207452295U (en) | A kind of cooling device for improving monocrystalline silicon pulling rate | |
| CN103966668A (en) | Growth method for controlling diameter of rod-like sapphire crystal based on protective atmosphere | |
| CN111116013A (en) | Molding and cooling device and method for fluorophosphate optical glass | |
| CN202297866U (en) | Argon gas cooling device of polysilicon ingot furnace | |
| CN2900558Y (en) | Straight drawing type crystal growing furnace based on temperature predicating compensation | |
| CN205893453U (en) | Guide cylinder for single crystal furnaces | |
| CN208791811U (en) | Crystal growing apparatus | |
| CN106222741A (en) | One exempts from out heat-insulation cage ingot casting device and method | |
| CN101220502A (en) | Vertical Bridgman growth furnace and method of optimizing temperature field inside furnace | |
| CN107252881A (en) | The crystallizer of copper is produced for up-drawing method | |
| CN209338399U (en) | A kind of direct yarn bushing air cooler of glass fibre | |
| CN211921735U (en) | Cooling device for improving pulling speed of monocrystalline silicon | |
| CN217398740U (en) | Device for uniformly cooling platinum tube | |
| CN217351610U (en) | Lifting furnace | |
| CN112746311A (en) | Single crystal furnace water cooling system based on PLC | |
| CN216738629U (en) | Water cooling screen for producing silicon single crystal rod | |
| CN108330534A (en) | A kind of water distributor structure of single crystal furnace cooling water | |
| CN106637385A (en) | Cz (Czochralski) crystal heater convenient for temperature gradient regulation and Cz crystal method | |
| CN110820043A (en) | Crystal growth apparatus and growth method | |
| CN102747420A (en) | Heat exchange table for polycrystalline ingot furnace and ventilation pipe diameter variation method of heat exchange table |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |