TW202305207A - Crystal pulling furnace - Google Patents

Abstract

The invention discloses a crystal pulling furnace which comprises a furnace body provided with a cavity and a crystal pulling opening communicated with the cavity. The supporting seat is arranged in the cavity; the crucible is arranged on the supporting seat; the guide cylinder is arranged between the crucible and the crystal pulling opening; the filtering device is arranged on the inner side wall of the guide cylinder, a crystal pulling channel is formed in the position, corresponding to the crystal pulling opening, of the filtering device, and a plurality of airflow channels are formed in the filtering device.

Description

Crystal puller

The invention belongs to the technical field of crystal pulling furnaces, in particular to a crystal pulling furnace.

With the continuous improvement of the quality of semiconductor silicon wafers, there are higher requirements for the control of crystal defects in crystal rods during the crystal pulling process. There are two main factors affecting crystal defects. One is the technical parameters of crystal pulling. The technical parameters of pulling the crystal can produce better quality crystal rods; the second is the structure and performance of the thermal field, which is a prerequisite for the quality of the crystal rod, and the thermal field is a crucial component of the crystal pulling furnace , due to the strict requirements on the crystal pulling environment of the crystal pulling furnace, the quality and material requirements of the thermal field are extremely high, not only high temperature resistance, good thermal stability, but also high purity.

During the crystal pulling process, it is necessary to fill the crystal pulling furnace with inert gas. One is to maintain a constant pressure in the furnace and give the crystal a stable growth space; the other is to take away a large amount of SiO gas and impurities generated during the crystal growth process to avoid these substances. A large amount is deposited on the surface of the thermal field components, affecting its normal use. In the related technology, the sudden change of the local temperature field or the turbulent flow of the inert gas often causes the crystal to break, and the single crystal is transformed into a polycrystalline growth. After the break occurs, it generally needs to be melted back or lifted, which not only increases the cost, but also increases the cost. Moreover, the overall yield rate of the ingot is reduced, which affects the normal and orderly progress of crystal pulling.

The purpose of the embodiments of the present invention is to provide a crystal pulling furnace, which is used to solve the problem that sudden changes in the local temperature field affect crystal pulling during the crystal pulling process.

An embodiment of the present invention provides a crystal pulling furnace, comprising: A furnace body, the furnace body has a chamber, and the furnace body is provided with a crystal pulling port communicated with the chamber; a support seat, the support seat is arranged in the chamber; a crucible, the crucible is arranged on the support base; A draft tube, the draft tube is arranged between the crucible and the crystal pulling port; A filtering device, the filtering device is arranged on the inner side wall of the guide cylinder, a crystal pulling channel is arranged on the filtering device corresponding to the crystal pulling port, and a plurality of air flow channels are arranged on the filtering device.

Wherein, the filter device includes an annular plate, and the outer periphery of the annular plate is connected with the inner side wall of the guide tube.

Wherein, the filter device includes a cone, the airflow channel is arranged on the side wall of the cone, the crystal pulling channel runs through the axis of the cone, and the diameter of the end of the cone near the crystal pulling port is smaller than that of the cone away from The diameter of one end of the crystal puller.

Wherein, the inner side wall of the guide tube is provided with a supporting platform, and the bottom of the filtering device is arranged on the supporting platform.

Wherein, the orthographic projection of the filtering device on the first plane is located within the orthographic projection of the crucible on the first plane, and the first plane is perpendicular to the axis of the furnace body.

Wherein, the orthographic projection of the draft tube on the first plane is located within the orthographic projection of the crucible on the first plane, and the first plane is perpendicular to the axis of the furnace body.

Wherein, the inner wall of the chamber is provided with a deflector, and the deflector extends along the circumferential direction of the inner wall of the chamber, and the deflector is arranged on the outer side of the guide tube, and the guide tube and the guide tube Flow plate connection.

Wherein, at least one of the deflector and the deflector is a piece of thermal insulation material; and/or The surface of at least one of the deflector and the deflector is provided with an insulating layer.

Wherein, the gas flow channel includes a first channel and a second channel communicated with the first channel, the first channel is set away from the crucible, the second channel is set close to the crucible, the diameter of the first channel is larger than that of the second channel diameter of.

Wherein, the number of the airflow channel is multiple, and a plurality of the airflow channels are evenly distributed on the filter device; and/or The axis of the draft tube is collinear or parallel to the axis of the furnace body; and/or The axis of the crystal pulling channel is collinear or parallel to the axis of the furnace body.

The crystal pulling furnace according to the embodiment of the present invention includes: a furnace body, the furnace body has a chamber, and the furnace body is provided with a crystal pulling port communicated with the chamber; a support seat, the support seat is arranged in the chamber; a crucible , the crucible is arranged on the support base; the guide cylinder, the guide cylinder is arranged between the crucible and the crystal pulling port; the filter device, the filter device is arranged on the inner wall of the guide cylinder, the filter device A crystal pulling channel is provided at a position corresponding to the crystal pulling port, and a plurality of airflow channels are provided on the filtering device.

In the crystal pulling furnace of the embodiment of the present invention, the filter device is arranged on the inner wall of the guide cylinder, and the position corresponding to the crystal pulling port on the filter device is provided with a crystal pulling channel, and the filter device is provided with a plurality of Airflow channel. The silicon oxide formed by the reaction between the silicon melt and the quartz crucible can be filtered through the filter device, and the condensation of silicon oxide above the crystal pulling furnace and other particulate objects above the crystal pulling furnace or other impurities in the inert gas flow can be filtered to prevent colder substances from falling into the crystal growth. Near the solid-liquid interface of the solid-liquid interface, prevent the thermal shock caused by the colder substance and avoid local temperature fluctuations. During the crystal pulling process, the filter device can block the generated silicon oxide gas from floating upward, and the inert gas flows from the top to the bottom. After passing through the filter device, the solid impurity particles can be filtered out. At the same time, the air flow channel of the filter device can change the turbulent flow of the inert gas. , so that the passing airflow passes over the surface of the melt in an orderly manner, and the silicon oxide gas is taken away in time. The filter device can effectively prevent the generation of thermal shock, reduce the turbulent flow of inert gas, greatly reduce the probability of crystal ingot disconnection, and improve the crystal ingot overall yield.

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

It should be noted that when an element is referred to as being “fixed” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

It is to be understood that the terms "length", "width", "top", "bottom", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device Or elements must have a certain orientation, be constructed and operate in a certain orientation, and thus should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of said features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those with ordinary knowledge in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

The crystal pulling furnace provided by the embodiment of the present application will be described in detail below through specific embodiments and application scenarios as shown in FIG. 1 to FIG. 4 .

As shown in FIGS. 1 to 4 , the crystal pulling furnace of the embodiment of the present invention includes: a furnace body 10 , a support base 20 , a crucible 30 , a draft tube 40 and a filtering device 50 , the furnace body 10 has a chamber 11 , and the furnace body 10 A crystal pulling port 12 communicating with the chamber 11 is provided, and crystal pulling can be performed through the crystal pulling port 12 . The support seat 20 is arranged in the chamber 11, the support seat 20 can include a support rod and a base, the lower end of the support rod is connected to the inner bottom wall of the chamber, the base can be arranged on the upper end of the support rod, and the axis of the support rod can be aligned with the The axes of the furnace body are parallel or coincident. The crucible 30 is set on the support base 20, the crucible 30 can be set on the base, the support rod can be rotated, and the rotation of the support rod can drive the crucible 30 to rotate, so that the crucible 30 can be heated evenly. The guide cylinder 40 can be arranged between the crucible 30 and the crystal pulling port 12 , and the guide cylinder 40 can be blocked and erected to guide the flow, so that the airflow can flow to the silicon melt 33 of the crucible 30 so as to drive the generated oxides. The crucible 30 may include a graphite crucible 31 and a quartz crucible 32 , the graphite crucible 31 may be set on the support base 20 , and the quartz crucible 32 may be set inside the graphite crucible 31 .

The filter device 50 can be arranged on the inner side wall of the guide cylinder 40, the filter device 50 can be arranged at the lower end position of the guide cylinder 40, and the position corresponding to the crystal pulling port 12 on the filter device 50 can be provided with a crystal pulling channel. The channel can be circular, and the crystal pulling channel can be used to facilitate crystal pulling and facilitate the passage of crystal rods 60 . A plurality of airflow channels 53 may be provided on the filter device 50, and the plurality of airflow channels 53 may be arranged at intervals. The number of filter devices 50 can be one or more, for example, there are multiple filter devices 50 , and multiple filter devices 50 can be arranged at intervals along the axial direction of the guide cylinder 40 to enhance the filtering and flow guiding effects.

In the crystal pulling furnace of the embodiment of the present invention, the filter device 50 is arranged on the inner side wall of the guide cylinder 40, and the position corresponding to the crystal pulling port 12 on the filter device 50 is provided with a crystal pulling channel, and the filter device 50 is provided with multiple Airflow channel 53. Through the filter device 50, the condensate of silicon oxide generated by the reaction between the silicon melt and the quartz crucible above the crystal pulling furnace and other particulate objects above the crystal pulling furnace or other impurities in the inert gas flow can be filtered to prevent colder substances from falling to the crystal. Near the growing solid-liquid interface, prevent thermal shock from cooler substances and avoid local temperature fluctuations. During the crystal pulling process, the filter device 50 can block the generated silicon oxide gas from floating upward, and the inert gas flows from the top to the bottom. After passing through the filter device 50, the solid impurity particles can be filtered out. The turbulent flow of the inert gas makes the passing airflow pass over the surface of the melt in an orderly manner, and the silicon oxide gas is taken away in time. The generation of thermal shock can be effectively prevented through the filter device 50, the turbulent flow of the inert gas is reduced, and the possibility of crystal rod breakage is greatly reduced. probability and improve the overall yield of crystal ingots.

In some embodiments, as shown in FIG. 1 , the filtering device 50 may include an annular plate, the outer periphery of which is connected to the inner wall of the draft tube 40 , and the axis of the annular plate may be parallel to or coincident with the axis of the furnace body 10 . A plurality of gas flow channels 53 may be arranged on the annular plate at intervals, and the circular hole in the middle of the annular plate serves as a crystal pulling channel. After passing through the annular plate, solid impurity particles can be filtered out. At the same time, the air flow channel 53 of the annular plate can change the turbulent flow of the inert gas, so that the passing air flow can pass over the surface of the melt in an orderly manner, and the silicon oxide gas can be taken away in time. Through the annular plate, it can effectively Prevent thermal shock and reduce turbulent flow of inert gas.

In some other embodiments, as shown in FIGS. 3 to 4 , the filter device 50 may include a cone, the air flow channel 53 is arranged on the side wall of the cone, the crystal pulling channel runs through the axis of the cone, and the cone is close to the puller. The diameter of one end of the crystal port 12 is smaller than the diameter of the end of the cone away from the crystal pulling port 12, which is convenient for filtering solid impurity particles through the gas flow channel 53, so that the gas flow channel 53 can change the turbulent flow of the inert gas. The side wall of the cone has a certain inclination angle, which can change the direction of the inert gas flow, so that it can be evenly blown to the surface of the ingot, so as to accelerate the cooling of the ingot and increase the crystal pulling rate. After the particles are blocked, the particles can move down along the outer wall of the cone, reducing the blockage of the airflow channel 53 .

Optionally, as shown in FIGS. 1 to 4 , a support platform 41 may be provided on the inner side wall of the draft tube 40 , and the support platform 41 may extend along the circumferential direction of the inner side wall of the draft tube 40 , and the bottom of the filter device 50 It is arranged on the supporting platform 41 , and the filtering device 50 can be supported by the supporting platform 41 . A sealing structure may be provided between the bottom of the filtering device 50 and the upper surface of the supporting platform 41 to reduce the gap and prevent solid impurities or air flow from passing through the gap. The bottom edge of the cone can be set on the support platform 41 , the outer wall of the cone can be spaced apart from the inner wall of the guide tube 40 , and the axis of the cone can be parallel or coincident with the axis of the furnace body 10 .

The area between the inner side wall of the guide tube 40 and the outer side wall of the cone can be provided with a groove on the support table 41, and after the particles are blocked, the particles can move down along the outer side of the cone and pass through the groove. It can accommodate and collect solid particles, reducing the blockage of the airflow channel 53 .

Optionally, the orthographic projection of the filtering device 50 on the first plane may be located within the orthographic projection of the crucible 30 on the first plane, and the first plane is perpendicular to the axis of the furnace body 10 to prevent solid impurity particles from entering the molten material in the crucible 30. body, so that the gas passing through the gas flow channel 53 can skim over the surface of the melt in an orderly manner, take away the silicon oxide gas in time, and effectively prevent the generation of thermal shock.

Optionally, the orthographic projection of the draft tube 40 on the first plane is located within the orthographic projection of the crucible 30 on the first plane, and the first plane is perpendicular to the axis of the furnace body 10, so that the diverted gas can be swept in an orderly manner. Over the surface of the melt, the silicon oxide gas is taken away in time.

In some embodiments, the inner wall of the chamber 11 may be provided with a deflector 42 , the deflector 42 may extend along the circumference of the inner wall of the chamber 11 , and the deflector 42 may be disposed on the outside of the deflector cylinder 40 , the guide cylinder 40 and the guide plate 42 can be connected. After the gas passing through the gas flow channel 53 has swept over the surface of the melt in an orderly manner, the gas with oxides can flow along the inner sidewall of the furnace body 10 to the bottom of the furnace body 10 through the flow guide of the deflector plate 42, so as to bring Oxidation is removed to reduce the damage or influence of the oxide on the crucible 30, the support base 20 and other components.

In an embodiment of the present invention, at least one of the deflector 42 and the deflector cylinder 40 can be an insulating material, for example, the deflector 42 or the deflector 40 can be an insulating material, and the deflector 42 and the deflector The cylinders 40 can all be made of heat-insulating material, so as to improve the heat-insulating effect and reduce heat loss.

The surface of at least one of the deflector 42 and the deflector cylinder 40 can be provided with an insulating layer, such as, the surface of the deflector 42 or the deflector cylinder 40 can be provided with an insulation layer, and the surface of the deflector 42 and the deflector cylinder 40 All are equipped with an insulation layer, through which the insulation effect can be improved and heat loss can be reduced.

Optionally, as shown in FIG. 2 , the gas flow channel 53 may include a first channel 51 and a second channel 52 communicated with the first channel 51, the first channel 51 is set away from the crucible 30, and the second channel 52 is set close to the crucible 30, The diameter of the first channel 51 is larger than the diameter of the second channel 52 , which is convenient for filtering solid impurity particles through the gas flow channel 53 , so that the gas flow channel 53 can change the turbulent flow of the inert gas.

Optionally, the number of gas flow channels 53 is multiple, and the multiple gas flow channels 53 can be evenly distributed on the filter device 50, so that the gas flow channels 53 can change the turbulence of the inert gas, and the gas flow distribution is uniform.

Optionally, the axis of the draft tube 40 is collinear or parallel to the axis of the furnace body 10, and the axis of the crystal pulling channel is collinear or parallel to the axis of the furnace body 10, so that the draft tube and the crystal pulling channel are located at the center of the furnace body 10. The central position is conducive to the uniform distribution of airflow and temperature of the furnace body 10 .

Embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementations, and the above-mentioned specific implementations are only illustrative, rather than restrictive, and those with ordinary knowledge in the art Under the enlightenment of the present invention, without departing from the purpose of the present invention and the scope protected by the scope of the patent application, many forms can also be made, all of which belong to the protection of the present invention.

10: furnace body 11: chamber 12: Crystal port 20: Support seat 30: Crucible 31: graphite crucible 32: Quartz crucible 33: Silicon melt 40: deflector 41: support platform 42: deflector 50: Filtration device 51: The first channel 52:Second channel 53: Airflow channel 60: Ingot

Fig. 1 is a structural representation of crystal pulling furnace; Fig. 2 is a schematic diagram of the distribution of air passages; Fig. 3 is a partial schematic diagram of the filtering device being arranged on the supporting platform; Fig. 4 is a schematic diagram of a filter device disposed on a support platform.

10: furnace body

11: chamber

12: Crystal port

20: Support seat

30: Crucible

31: graphite crucible

32: Quartz crucible

33: Silicon melt

40: deflector

41: support table

42: deflector

50: Filtration device

60: Ingot

Claims (10)

A crystal pulling furnace, comprising: A furnace body, the furnace body has a chamber, and the furnace body is provided with a crystal pulling port communicated with the chamber; a support seat, the support seat is arranged in the chamber; a crucible, the crucible is arranged on the support base; A draft tube, the draft tube is arranged between the crucible and the crystal pulling port; A filtering device, the filtering device is arranged on the inner side wall of the guide cylinder, a crystal pulling channel is arranged on the filtering device corresponding to the crystal pulling port, and a plurality of air flow channels are arranged on the filtering device. The crystal pulling furnace as claimed in claim 1, wherein the filtering device comprises an annular plate, and the outer periphery of the annular plate is connected to the inner side wall of the draft tube. The crystal pulling furnace as claimed in claim 1, wherein the filter device includes a cone, the airflow channel is arranged on the side wall of the cone, the crystal pulling channel runs through the axis of the cone, and the cone is close to the The diameter of one end of the crystal pulling mouth is smaller than the diameter of the end of the cone tube away from the crystal pulling mouth. The crystal pulling furnace as claimed in claim 1, wherein the inner wall of the draft tube is provided with a support platform, and the bottom of the filtering device is arranged on the support platform. The crystal pulling furnace according to claim 1, wherein the orthographic projection of the filter device on the first plane is located within the orthographic projection of the crucible on the first plane, and the first plane is perpendicular to the axis of the furnace body. The crystal pulling furnace according to claim 1, wherein the orthographic projection of the draft tube on the first plane is located within the orthographic projection of the crucible on the first plane, and the first plane is perpendicular to the axis of the furnace body . The crystal pulling furnace as claimed in item 1, wherein, the inner wall of the chamber is provided with a deflector, and the deflector extends along the circumferential direction of the inner wall of the chamber, and the deflector is arranged on the The outside of the tube, the guide tube is connected with the guide plate. The crystal pulling furnace as claimed in claim 7, wherein at least one of the deflector and the deflector is a piece of thermal insulation material; and/or The surface of at least one of the deflector and the deflector is provided with an insulating layer. The crystal pulling furnace as claimed in item 1, wherein the gas flow channel includes a first channel and a second channel communicated with the first channel, the first channel is set away from the crucible, and the second channel is set close to the crucible, The diameter of the first channel is larger than the diameter of the second channel. The crystal pulling furnace as claimed in item 1, wherein a plurality of the gas flow channels are evenly distributed on the filtering device; and/or The axis of the draft tube is collinear or parallel to the axis of the furnace body; and/or The axis of the crystal pulling channel is collinear or parallel to the axis of the furnace body.

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