TWI812518B - Crystal puller - Google Patents

Abstract

The invention discloses a crystal pulling furnace, which includes: a furnace body, which has a chamber, and the furnace body is provided with a crystal pulling port connected to the chamber; a support seat, which is arranged in the chamber; and a crucible, which is arranged on the support. On the seat; the guide tube is arranged between the crucible and the crystal pulling port; the filtering device is arranged on the inner wall of the guide tube, and the crystal pulling channel is provided at the position corresponding to the crystal pulling port on the filtering device , the filter device is provided with multiple air flow channels.

Description

Crystal pulling furnace

The invention belongs to the technical field of crystal pulling furnaces, and specifically relates to a crystal pulling furnace.

With the continuous improvement of the quality of semiconductor silicon wafers, there are higher requirements for the management and control of crystal defects of crystal rods during the crystal pulling process. There are two main factors that affect crystal defects. One is the technical parameters of crystal pulling. With optimization The technical parameters of crystal pulling can produce better quality crystal ingots; the second is the structure and performance of the thermal field, its quality is a prerequisite for the quality of the crystal ingot, and the thermal field is a crucial component of the crystal pulling furnace. , due to the strict requirements of the crystal pulling environment of the crystal pulling furnace, the quality and material requirements of the thermal field are extremely high. It must not only be high temperature resistant, have good thermal stability, but also have high purity.

During the crystal pulling process, inert gas needs to be filled into the crystal pulling furnace. First, it maintains a constant pressure in the furnace and gives the crystal a stable growth space. Second, it takes away a large amount of SiO gas and impurities generated during the crystal growth process to avoid these substances. A large amount of deposits are deposited on the surface of thermal field components, affecting their normal use. In related technologies, sudden changes in the local temperature field or turbulence of inert gases often cause the crystal to break and transform from single crystal to polycrystalline growth. After the breakage occurs, it generally requires remelting or lifting operations, which not only increases the cost, but also increases the cost. Moreover, it reduces the overall yield of the crystal ingot and affects the normal and orderly progress of crystal pulling.

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

An embodiment of the present invention provides a crystal pulling furnace, including: The furnace body has a chamber, and the furnace body is provided with a crystal pulling port connected to the chamber; A support base, the support base is arranged in the chamber; Crucible, the crucible is arranged on the support base; A flow guide tube, which is arranged between the crucible and the crystal pulling mouth; A filtering device is provided on the inner wall of the guide tube. A crystal pulling channel is provided on the filtering device at a position corresponding to the crystal pulling opening. A plurality of air flow channels are provided on the filtering device.

Wherein, the filtering device includes an annular plate, and the outer periphery of the annular plate is connected to the inner wall of the guide tube.

Wherein, the filtering device includes a cone, the air flow channel is arranged on the side wall of the cone, the crystal pulling channel runs through the axial direction of the cone, and the diameter of the end of the cone close to the crystal pulling opening is smaller than the diameter of the end of the cone away from the cone. The diameter of one end of the crystal opening.

Wherein, the inner wall of the guide tube is provided with a support platform, and the bottom of the filter device is arranged on the support 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 guide 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 guide plate, the guide plate extends along the circumferential direction of the inner wall of the chamber, the guide plate is arranged on the outside of the guide tube, and the guide tube is connected with the guide tube. Flow board connection.

Wherein, at least one of the guide plate and the guide tube is a piece of thermal insulation material; and/or A thermal insulation layer is provided on the surface of at least one of the guide plate and the guide tube.

Wherein, the air flow channel includes a first channel and a second channel connected with the first channel. The first channel is located away from the crucible. The second channel is located close to the crucible. The diameter of the first channel is larger than that of the second channel. diameter.

Wherein, the number of the air flow channels is multiple, and the multiple air flow channels are evenly distributed on the filter device; and/or The axis of the guide 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 having a chamber and a crystal pulling port connected to the chamber; a support base disposed in the chamber; and a crucible , the crucible is arranged on the support seat; the flow guide tube is arranged between the crucible and the crystal pulling mouth; the filtering device is arranged on the inner wall of the flow guide tube, the filtering device A crystal pulling channel is provided at a position corresponding to the crystal pulling port, and a plurality of air flow channels are provided on the filtering device.

In the crystal pulling furnace of the embodiment of the present invention, the filtering device is arranged on the inner wall of the guide tube. The filtering device is provided with a crystal pulling channel at a position corresponding to the crystal pulling opening. The filtering device is provided with a plurality of crystal pulling channels. Airflow channel. The filtration device can filter the condensation of silicon oxide generated by the reaction between the silicon melt and the quartz crucible above the crystal pulling furnace, as well as other particulate matter above the crystal pulling furnace or other impurities in the inert gas flow, to prevent colder substances from falling into the crystal growth near the solid-liquid interface to prevent thermal shock from colder substances and avoid local temperature shocks. During the crystal pulling process, the filter device can block the generated silicon oxide gas from floating upward, and the inert gas flows from above to downward. 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 air flow passes over the melt surface in an orderly manner, taking away the silicon oxide gas in time. The filter device can effectively prevent the generation of thermal shock, reduce the turbulence of inert gas, greatly reduce the probability of crystal ingot breakage, and improve the crystal ingot overall yield.

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

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can 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 should be understood that the terms "length", "width", "top", "bottom", "front", "back", "left", "right", "vertical", "horizontal", "top", The orientations or positional relationships indicated by "bottom", "inner", "outside", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply the device referred to. Or elements must have a specific orientation, be constructed and operate in a specific orientation and therefore are not to be construed as limitations on the invention.

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

In the present invention, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interaction between two elements. For those with ordinary knowledge in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

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

As shown in Figures 1 to 4, the crystal pulling furnace according to the embodiment of the present invention includes: a furnace body 10, a support base 20, a crucible 30, a guide tube 40 and a filtering device 50. The furnace body 10 has a chamber 11. The furnace body 10 There is a crystal pulling port 12 connected with the chamber 11, and the crystal can be pulled through the crystal pulling port 12. The support base 20 is disposed in the chamber 11. The support base 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 disposed on the upper end of the support rod. The axis of the support rod can be connected to the inner bottom wall of the chamber. The axes of the furnace body are parallel or coincident. The crucible 30 is arranged on the support seat 20. The crucible 30 can be arranged on the base, and the support rod can rotate. The rotation of the support rod can drive the crucible 30 to rotate, so that the crucible 30 can be heated evenly. The flow guide tube 40 can be disposed between the crucible 30 and the crystal pulling port 12. The flow guide tube 40 can be blocked and stood up to guide the flow, so that the air flow can flow to the silicon melt 33 of the crucible 30 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 disposed on the support base 20, and the quartz crucible 32 may be disposed in the graphite crucible 31.

The filtering device 50 can be disposed on the inner wall of the guide tube 40. The filtering device 50 can be provided at the lower end of the guide tube 40. A crystal pulling channel can be provided on the filtering device 50 at a position corresponding to the crystal pulling port 12 to pull the crystal. The channel can be circular, and the crystal pulling channel can facilitate crystal pulling and facilitate the passage of the crystal rod 60 . A plurality of air flow channels 53 may be provided on the filter device 50 , and the plurality of air flow channels 53 may be arranged at intervals. The number of filtering devices 50 may be one or more. For example, the number of filtering devices 50 may be multiple. The plurality of filtering devices 50 may be spaced apart along the axial direction of the flow guide tube 40 to enhance the filtering and flow guiding effects.

In the crystal pulling furnace of the embodiment of the present invention, the filtering device 50 is disposed on the inner wall of the guide tube 40. The filtering device 50 is provided with a crystal pulling channel at a position corresponding to the crystal pulling port 12. The filtering device 50 is provided with a plurality of crystal pulling channels. 53 airflow channels. The filtering device 50 can filter the condensation of silicon oxide generated by the reaction between the silicon melt and the quartz crucible above the crystal pulling furnace, as well as other particulate matter above the crystal pulling furnace or other impurities in the inert gas flow, to prevent colder substances from falling into the crystal. Near the growing solid-liquid interface, it prevents thermal shock from colder substances and avoids local temperature shocks. 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 above to downward. After passing through the filter device 50, the existing solid impurity particles can be filtered out. At the same time, the air flow channel 53 of the filter device 50 can be changed. The turbulent flow of the inert gas causes the passing air flow to sweep over the melt surface in an orderly manner, taking away the silicon oxide gas in time. The filter device 50 can effectively prevent the generation of thermal shock, reduce the turbulent flow of the inert gas, and greatly reduce the risk of crystal ingot breakage. probability to improve the overall yield of the crystal ingot.

In some embodiments, as shown in FIG. 1 , the filtering device 50 may include an annular plate. The outer periphery of the annular plate is connected to the inner wall of the guide tube 40 . The axis of the annular plate may be parallel to or coincident with the axis of the furnace body 10 . A plurality of air flow channels 53 can 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, the existing solid impurity particles can be filtered out. At the same time, the air flow channel 53 of the annular plate can change the turbulence of the inert gas, so that the passing air flow passes over the melt surface in an orderly manner, taking away the silicon oxide gas in a timely manner. The annular plate can effectively Prevent the generation of thermal shock and reduce the turbulence of inert gas.

In other embodiments, as shown in FIGS. 3 to 4 , the filtering device 50 may include a cone, the airflow channel 53 is provided on the side wall of the cone, the crystal pulling channel runs through along the axis of the cone, and the cone is close to the puller. The diameter of one end of the crystal opening 12 is smaller than the diameter of the end of the cone away from the crystal opening 12, which facilitates filtering of solid impurity particles through the air flow channel 53, so that the air flow channel 53 can change the turbulent flow of inert gas. The side wall of the cone has a certain inclination angle, which can change the direction of the inert gas flow and blow it evenly to the surface of the crystal rod, speeding up the cooling of the crystal rod and increasing the crystal pulling rate. After the particles are blocked, the particles can move downward along the outer wall of the cone to reduce obstruction of the air flow channel 53 .

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

The support platform 41 can be provided with a groove in the area between the inner wall of the guide tube 40 and the outer wall of the cone. After the particles are blocked, the particles can move downward along the outer wall of the cone and pass through the groove. Solid particles can be accommodated and collected to reduce obstruction of the air flow channel 53 .

Alternatively, 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 melt in the crucible 30 body, so that the gas passing through the air flow channel 53 can pass over the melt surface in an orderly manner, taking away the silicon oxide gas in time, effectively preventing the generation of thermal shock.

Optionally, the orthographic projection of the guide 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 guided gas can sweep in an orderly manner. Passing through the melt surface, the silicon oxide gas is taken away in time.

In some embodiments, the inner wall of the chamber 11 may be provided with a baffle 42 , the baffle 42 may extend along the circumferential direction of the inner wall of the chamber 11 , and the baffle 42 may be disposed outside the baffle 40 , the guide tube 40 and the guide plate 42 can be connected. After the gas passing through the gas flow channel 53 passes over the melt surface in an orderly manner, the gas containing oxides can flow along the inner wall of the furnace body 10 toward the bottom of the furnace body 10 through the flow guide of the baffle plate 42 so as to bring the gas to the bottom of the furnace body 10. Remove oxides and reduce damage or impact of oxides on the crucible 30, the support base 20 and other components.

In the embodiment of the present invention, at least one of the guide plate 42 and the guide tube 40 can be a piece of thermal insulation material. For example, the guide plate 42 or the guide tube 40 can be a piece of thermal insulation material. The guide plate 42 and the guide tube 40 can be a piece of thermal insulation material. The tube 40 can all be made of thermal insulation material to improve the thermal insulation effect and reduce heat loss.

The surface of at least one of the guide plate 42 and the guide tube 40 can be provided with an insulation layer. For example, the surface of the guide plate 42 or the guide tube 40 can be provided with an insulation layer. The surfaces of the guide plate 42 and the guide tube 40 can be provided with an insulation layer. All are equipped with an insulation layer, which can improve the insulation effect and reduce heat loss.

Optionally, as shown in Figure 2, the air flow channel 53 may include a first channel 51 and a second channel 52 connected with the first channel 51. The first channel 51 is located away from the crucible 30, and the second channel 52 is located close to the crucible 30. The diameter of the first channel 51 is larger than the diameter of the second channel 52, which facilitates filtering of 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 air flow channels 53 is multiple, and the multiple air flow channels 53 can be evenly distributed on the filter device 50, so that the air flow channels 53 can change the turbulent flow of the inert gas and the air flow is evenly distributed.

Optionally, the axis of the flow guide 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 flow guide 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 air flow and temperature in the furnace body 10 .

The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above-mentioned specific implementations. The above-mentioned specific implementations are only illustrative and not restrictive. Those with ordinary knowledge in the art Under the inspiration of the present invention, many forms can be made without departing from the spirit of the present invention and the protection scope of the patent application, all of which fall within the protection of the present invention.

10: Furnace body 11: Chamber 12: Crystal pulling mouth 20: Support base 30:Crucible 31:Graphite crucible 32:Quartz crucible 33:Silicon melt 40: guide tube 41:Support platform 42:Deflector 50:Filter device 51:First channel 52:Second channel 53:Air flow channel 60:crystal rod

Figure 1 is a schematic structural diagram of a crystal pulling furnace; Figure 2 is a schematic diagram of the distribution of air flow channels; Figure 3 is a partial schematic diagram of the filter device installed on the support platform; Figure 4 is a schematic diagram of the filter device installed on the support platform.

10: Furnace body

11: Chamber

12: Crystal pulling mouth

20: Support base

30:Crucible

31:Graphite crucible

32:Quartz crucible

33:Silicon melt

40: guide tube

41:Support platform

42:Deflector

50:Filter device

60:crystal rod

Claims (10)

A crystal pulling furnace includes: The furnace body has a chamber, and the furnace body is provided with a crystal pulling port connected to the chamber; A support base, the support base is arranged in the chamber; Crucible, the crucible is arranged on the support base; A flow guide tube, which is arranged between the crucible and the crystal pulling mouth; A filtering device is provided on the inner wall of the guide tube. A crystal pulling channel is provided on the filtering device at a position corresponding to the crystal pulling opening. A plurality of air flow channels are provided on the filtering device. The crystal pulling furnace of claim 1, wherein the filtering device includes an annular plate, and the outer periphery of the annular plate is connected to the inner wall of the guide tube. The crystal pulling furnace according to claim 1, wherein the filtering device includes a cone, the air flow channel is provided on the side wall of the cone, the crystal pulling channel runs through along the axial direction of the cone, and the cone is close to the cone. The diameter of one end of the crystal pulling opening is smaller than the diameter of the end of the cone away from the crystal pulling opening. The crystal pulling furnace of claim 1, wherein the inner wall of the guide tube is provided with a support platform, and the bottom of the filtering device is disposed on the support platform. The crystal pulling furnace of claim 1, 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. The crystal pulling furnace of claim 1, wherein the orthographic projection of the guide 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 according to claim 1, wherein the inner wall of the chamber is provided with a guide plate, the guide plate extends along the circumferential direction of the inner wall of the chamber, and the guide plate is disposed on the guide plate. On the outside of the tube, the guide tube is connected to the guide plate. The crystal pulling furnace according to claim 7, wherein at least one of the guide plate and the guide tube is an insulating material piece; and/or A thermal insulation layer is provided on the surface of at least one of the guide plate and the guide tube. The crystal pulling furnace according to claim 1, wherein the air flow channel includes a first channel and a second channel connected to the first channel, the first channel is located away from the crucible, and the second channel is located close to the crucible, The diameter of the first channel is greater than the diameter of the second channel. The crystal pulling furnace according to claim 1, wherein a plurality of the air flow channels are evenly distributed on the filtering device; and/or The axis of the guide 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.