Single crystal furnace

Abstract

The utility model is suitable for the technical field of monocrystalline silicon manufacturing, and provides a single crystal furnace, which comprises a crucible body, a crucible body and a crucible cover, the plurality of heating structures are sequentially arranged at intervals in the vertical direction, are wound on at least part of the crucible body, and comprise heating main bodies and electrode mounting seats connected with the heating main bodies; the furnace body is wound outside the multiple heating structures, and the multiple electrodes are installed on the furnace body and connected with the multiple electrode installation bases in a one-to-one correspondence mode. According to the single crystal furnace disclosed by the utility model, each heating structure can be regulated and controlled to have different heating amounts on different areas of the pot body, so that the temperature gradient of a thermal field is more uniform and stable, and therefore, when the pot body does lifting motion in the vertical direction, the heating temperatures of the heating main bodies with different distances from corner areas of the pot body can be controlled to be different; the condition that oxygen is separated out and enters silicon lattices due to the fact that the temperature of the corner area of the pot body is too high is avoided, and the purity of a single crystal silicon rod is controlled.

Description

Technical Field

[0001] The utility model belongs to the technical field of single crystal silicon manufacturing, and particularly relates to a single crystal furnace. Background Art

[0002] As a basic material for photovoltaic power generation, single crystal silicon wafers have a wide market demand. The Czochralski single crystal growth method is a common single crystal growth method. Its growth process is carried out in a single crystal furnace. The melt is contained in a quartz crucible, and the quartz crucible is continuously heated by a heater. A seed crystal is immersed in the melt, and processes such as seeding, shoulder formation, shoulder turning, equal diameter and end finishing are carried out in sequence, and finally a single crystal silicon rod is obtained.

[0003] When preparing a single crystal silicon rod by a single crystal furnace, since the main component of the quartz crucible is SiO2 and the oxygen content is the highest in the corner area of the quartz crucible, when the heater heats the quartz crucible, oxygen in this area is easily precipitated and enters the lattice, reducing the yield of the single crystal rod product. Eventually, quality problems such as concentric circles appear in the prepared solar cells, increasing the scrap rate. Summary of the Utility Model

[0004] The single crystal furnace provided by the embodiment of the utility model aims to solve the problem that oxygen in the quartz crucible in the prior art is easily precipitated and enters the lattice, reducing the yield of the single crystal rod product.

[0005] In a first aspect, the embodiment of the utility model provides a single crystal furnace, including:

[0006] A crucible body capable of moving up and down under the drive of a driving member;

[0007] A plurality of heating structures are sequentially arranged at intervals in the vertical direction and are wound around at least part of the crucible body, including a heating main body and an electrode mounting seat connected to the heating main body;

[0008] A furnace body is wound around the plurality of heating structures;

[0009] A plurality of electrodes are installed on the furnace body and are respectively connected to the plurality of electrode mounting seats in one-to-one correspondence.

[0010] Furthermore, the heating main body is in a wavy shape.

[0011] Furthermore, the height range of the heating main body is 50 mm - 260 mm.

[0012] Furthermore, the height of the heating main body at the lowermost position is less than the height of the remaining heating main bodies.

[0013] Furthermore, the electrode mounting seats are respectively detachably connected to the heating main body and the electrodes, and the electrodes are detachably connected to the furnace body.

[0014] Furthermore, one end of the electrode mounting base is connected to the heating body through a bolt, and the other end of the electrode mounting base is threadedly connected to the electrode.

[0015] Furthermore, the electrode mounting base includes a first section, a second section, and a third section connected in sequence. The first section is provided with a first mounting hole, and a first internal thread for connecting to the heating body is provided on the inner wall of the first mounting hole. The third section is provided with a second mounting hole for connecting to the electrode, and a second internal thread for connecting to the electrode is provided on the inner wall of the second mounting hole.

[0016] Furthermore, there are distances between the bolt and the electrode and one end of the second section respectively;

[0017] The second section is provided with a through hole extending along the axis, and the through hole is respectively communicated with the first mounting hole and the second mounting hole. The second section is provided with an exhaust hole in the radial direction, and the exhaust hole is communicated with the through hole.

[0018] Furthermore, the aperture of the first mounting hole and the aperture of the second mounting hole are both larger than the aperture of the through hole.

[0019] Furthermore, the first section is provided with a first annular notch at the end of the first mounting hole facing the second section, and the aperture of the first annular notch is larger than the aperture of the first mounting hole; and / or the third section is provided with a second annular notch at the end of the second mounting hole facing the second section, and the aperture of the second annular notch is larger than the aperture of the second mounting hole.

[0020] The beneficial effects achieved by the present utility model are as follows: The electrode is installed through the furnace body, the electrode is connected to an external power supply, and the heating body is connected through the electrode mounting base. After the electrode is energized, the heating body can heat the melt in the pot body. Since there are multiple heating structures outside the pot body, each heating structure can be adjusted to have different heating amounts for different regions of the heating structure, so that different regions of the heating structure are heated differently, making the temperature gradient of the thermal field more uniform and stable. When the pot body moves up and down in the vertical direction, the heating temperatures of different heating bodies at different distances from the corner area of the pot body can be controlled, thus avoiding the situation where the temperature of the arc-shaped corner wall is too high and oxygen is precipitated and enters the silicon lattice, controlling the purity of the single crystal rod, and ensuring the quality of the single crystal rod. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of a single crystal furnace provided by an embodiment of the present utility model;

[0022] Figure 2 is Figure 1 a cross-sectional schematic diagram of the single crystal furnace in

[0023] Figure 3 is Figure 2 a schematic structural view of the heating structure and the electrode in

[0024] Figure 4 is Figure 3 a schematic structural view of the electrode mounting seat and the electrode in

[0025] Figure 5 is Figure 4 a schematic cross-sectional view of the electrode mounting seat and the electrode in

[0026] Description of main component symbols: 100 - single crystal furnace, 10 - quartz crucible, 11 - straight wall, 12 - arc corner wall, 13 - bottom wall, 20 - heating structure, 21 - heating main body, 22 - electrode mounting seat, 221 - first section, 2211 - first mounting hole, 2212 - first annular notch, 222 - second section, 2221 - through hole, 2222 - exhaust hole, 223 - third section, 2231 - second mounting hole, 2232 - second annular notch, 30 - furnace body, 40 - electrode, 50 - bolt, 60 - central axis of the crucible. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0028] Briefly describe the distinguishing features between the present utility model and the prior art, and these distinguishing features constitute the innovative points of the present utility model

[0029] Embodiment 1

[0030] Please refer to Figures 1 to 3 , which is a single crystal furnace 100 provided by the first embodiment of the present utility model, including a crucible body 10, a plurality of heating structures 20, a furnace body 30 and electrodes 40.

[0031] Among them, the crucible body 10 can move up and down under the drive of a driving member; a plurality of heating structures 20 are arranged at intervals in the vertical direction and are wound around at least part of the crucible body 10, including a heating main body 21 and an electrode mounting seat 22 connected to the heating main body 21; the furnace body 30 is wound around a plurality of heating structures 20; a plurality of electrodes 40 are installed on the furnace body 30 and are connected to a plurality of electrode mounting seats 22 in one-to-one correspondence.

[0032] The above single crystal furnace 100 installs the electrodes 40 through the furnace body 30. The electrodes 40 are connected to an external power supply and are connected to the heating body 21 through the electrode mounting seat 22. After the electrodes 40 are energized, the heating body 21 can heat the melt in the crucible 10. Since there are multiple heating structures 20 outside the crucible 10, the heating amounts of each heating structure 20 for different regions of the crucible 10 can be adjusted, so that the heat received by different regions of the crucible 10 is different, making the temperature gradient of the thermal field more uniform and stable. Thus, when the crucible 10 moves up and down in the vertical direction, the heating temperatures of different heating bodies 21 at different distances from the corner region of the crucible 10 can be controlled, thereby avoiding the situation where the temperature of the arc-shaped corner wall 12 is too high, resulting in oxygen precipitation and entering the silicon lattice, controlling the purity of the single crystal rod, ensuring the quality of the single crystal rod, and avoiding the appearance of concentric circles during the later preparation of solar cells.

[0033] Specifically, the crucible 10 of this embodiment is also provided with a layer of surrounding carbon crucible band. The quartz crucible has a straight wall 11, an arc-shaped corner wall 12, and a bottom wall 13 connected in sequence, and the carbon crucible band surrounds the outside of the straight wall 11. Among them, the silicon material is placed in the crucible 10 and heated to melt into a melt. It can be understood that the single crystal furnace 100 of this embodiment also includes a crucible central axis 60, and the crucible central axis 60 is used to support the bottom of the crucible 10 to drive the crucible 10 to move up and down under the drive of a driving member; it can also include a heat insulation layer, and the heat insulation layer is arranged between the heating body 21 and the furnace body 30 to insulate the crucible 10 and prevent the heat in the crucible 10 from quickly escaping; the single crystal furnace 100 can also include a guide cylinder, and an inert gas, such as helium, is introduced through the guide cylinder to purge the impurities precipitated from the silicon material, blow away the silicon monoxide particles generated when the polysilicon melts, and discharge them through the bottom of the furnace body 30.

[0034] Among them, as the crystal pulling continues, in the initial stage, the heating body 21 is located at the straight wall 10 stage, and at this time the arc-shaped corner wall 12 is not heated. As the crystal pulling progresses, the crucible will rise at a certain speed as the liquid silicon in the crucible decreases to ensure that the relative position of the solid-liquid interface in the entire temperature field remains unchanged. During the movement, the arc-shaped corner wall 12 will enter the range of the heating body 21 located below. At this time, the heating temperature of the heating body 21 can be controlled, so as to accurately control the heating temperature of the arc-shaped corner wall 12 and avoid oxygen precipitation.

[0035] Among them, when the electrode 40 is connected to an external power supply, the heating body 21 generates heat to continuously heat the silicon material in the pot body 10, gradually melting the silicon material into molten material. When setting multiple heating structures 20, each heating body 21 can be set to have the same height, or each can have different heights, or some of the heating bodies 21 are set to one height and the other part of the heating bodies 21 is set to another height, or the height of the heating body 21 gradually increases in the direction from top to bottom, or the height gradually decreases in the direction from top to bottom, which is not limited herein. Thus, when heating bodies 21 of different heights are set, the heat generation amounts of the respective heating bodies 21 are different, so as to be able to release different amounts of heat to the pot body 10, thereby enabling the heat supply to different regions of the pot body 10 to be controlled as needed to ensure temperature control of the molten material. It can be understood that the higher the heating body 21, the more heat it can generate.

[0036] Embodiment 2

[0037] Among them, please refer to Figure 3 , in this embodiment, when setting the heating body 21, the heating body 21 is in a wavy shape. Thus, the heating body 21 can have a greater extension length to achieve the effect of increasing the heat generation amount.

[0038] Furthermore, when the heating body 21 is set to a wavy shape, both the upper surface and the lower surface of the heating body 21 can be set to be flat, so as to facilitate the spaced arrangement of multiple heating bodies 21 in the vertical direction and make full use of the space.

[0039] Embodiment 3

[0040] Furthermore, when setting the heating body 21, the height range of the heating body 21 is 50 mm - 260 mm. Thus, each heating body 21 has an appropriate height, avoiding the situation that when the height of the heating body 21 is set too large, the coverage range of each heating body 21 on the straight wall 11 is large and it is difficult to precisely control the heating temperature at the required position on the straight wall 11; and avoiding the situation that when the height of the heating body 21 is too small, a larger number of heating bodies 21 need to be set, increasing the setting cost of the heating structure 20.

[0041] Even further, the height range of the heating body 21 is preferably 150 mm - 240 mm, so that the height of the heating body 21 is neither too large nor too small, facilitating the installation of multiple heating bodies 21 and ensuring the installation cost.

[0042] Among them, the height of the heating body 21 can be set to values such as 150 mm, 180 mm, 200 mm, 220 mm, 240 mm, etc., which is not limited herein.

[0043] Embodiment 4

[0044] Among them, in order to more accurately control the temperature at the position of the straight wall 11 close to the arc-shaped corner wall 12, in this embodiment, the height of the heating main body 21 at the bottom is set to be less than the height of the other heating main bodies 21. In this way, the height of the heating main body 21 at the bottom is set to be the smallest, and the heating area corresponding to the straight wall 11 is the smallest. Since the heating main body 21 at the bottom is directly close to the arc-shaped corner wall 12, the temperature of the area of the arc-shaped corner wall 12 can be more accurately controlled. In this way, the lowest temperature can be controlled at the position close to the arc-shaped corner wall 12, so as to reduce the oxygen evolution of the arc-shaped corner wall 12.

[0045] For example, in some embodiments, the height of the heating main body 21 at the bottom can be set to 150 mm, and the height of the other heating main bodies 21 above can be set to 180 mm; the height of the heating main body 21 at the bottom can be set to 180 mm, and the height of the other heating main bodies 21 above can be set to 200 mm.

[0046] Embodiment Five

[0047] In an embodiment of the present utility model, in order to facilitate the cleaning of the heating structure 20 and the maintenance of the single crystal furnace 100, the electrode mounting seat 22 is detachably connected to the heating main body 21 and the electrode 40 respectively, and the electrode 40 is detachably connected to the furnace body 30. In this way, after a silicon rod is produced, by detachably separating the electrode mounting seat 22 from the heating main body 21 and the furnace body 30 respectively, the heating main body 21 can be removed from the furnace body 30, so as to clean the impurities deposited on the surface of the heating main body 21 and ensure that the heat generated by the heating main body 21 in the later stage can be quickly radiated to the pot body 10.

[0048] Among them, the detachable connection method between the electrode mounting seat 22 and the heating main body 21 can be plugging, clamping and other methods, and the detachable connection method between the electrode 40 and the electrode mounting seat 22 can also be set as plugging, clamping and other methods, which are not limited here.

[0049] It can be understood that each heating main body 21 needs to be connected to an input pole and an output pole. Therefore, two electrode mounting seats 22 need to be installed on each heating main body 21. Specifically, the two electrode mounting seats 22 on each heating main body 21 in this embodiment are arranged opposite to each other along the radial direction of the heating main body 21, so as to facilitate the arrangement of the two electrode mounting seats 22.

[0050] Furthermore, the electrode mounting seats 22 on one side of the multiple heating main bodies 21 are located on the same straight line in the vertical direction.

[0051] Embodiment Six

[0052] Specifically, please refer toFigure 4 and Figure 5 In order to ensure the connection stability between the electrode mounting seat 22 and the heating body 21 and the furnace body 30 respectively, the electrode mounting seat 22 is threadedly connected to the heating body 21 and the electrode 40 respectively, and the electrode 40 is threadedly connected to the furnace body 30. That is, when the electrode mounting seat 22 and the heating body 21 are installed, one end of the electrode mounting seat 22 is installed with the heating body 21 through the bolt 50, so that the electrode mounting seat 22 can be stably installed with the heating body 21 as a whole; when the electrode mounting seat 22 and the electrode 40 are installed, the other end of the electrode mounting seat 22 can be provided with internal threads or external threads, and one of the electrode mounting seat 22 and the electrode 40 is internal threads and the other is external threads, so as to realize the installation of the electrode mounting seat 22 and the electrode 40.

[0053] Further, when the electrode 40 and the furnace body 30 are installed, a connection seat can be provided on the furnace body 30 to ensure the connection area with the electrode 40, so as to ensure the installation strength of the electrode 40 on the furnace body 30. After the electrode 40 and the furnace body 30 are threadedly connected, the electrode 40 passes through the furnace body 30 and then is connected to the electrode mounting seat 22.

[0054] Specifically, the electrode mounting seat 22 of this embodiment is provided with internal threads, and the electrode 40 is provided with external threads. The electrode 40 is screwed into the electrode mounting seat 22 to realize the installation of the electrode 40.

[0055] Embodiment Seven

[0056] Please refer to Figure 5 , in order to ensure the installation strength between the electrode mounting seat 22 and the heating body 21 and the electrode 40 respectively, the electrode mounting seat 22 includes a first section 221, a second section 222 and a third section 223 connected in sequence. The first section 221 is provided with a first mounting hole 2211, and the hole wall of the first mounting hole 2211 is provided with a first internal thread for connecting with the heating body 21. The third section 223 is provided with a second mounting hole 2231 for connecting with the electrode 40, and the hole wall of the second mounting hole is provided with a second internal thread. By further providing a second section 222 between the first section 221 and the third section 223, since the second section 222 does not need to be connected to the bolt 50 or the electrode 40 and does not need to be provided with internal threads. For example, the second section 222 can be provided in a solid manner to ensure the structural strength of the electrode mounting seat 22.

[0057] Embodiment Eight

[0058] Furthermore, since the electrode 40 and the bolt 50 are respectively threadedly connected to the electrode mounting seat 22 and are both inserted into the electrode mounting seat 22, as the heating body 21 heats up, the temperature inside the entire furnace body 30 rises, and the air pressure inside the electrode mounting seat 22 expands. To ensure the safety of the single crystal furnace 100 during use, there is a gap between the bolt 50, the electrode 40 and one end of the second section 222 respectively; the second section 222 is provided with a through hole 2221 extending along the axis, and the through hole 2221 is respectively communicated with the first mounting hole 2211 and the second mounting hole 2231. The second section 222 is provided with exhaust holes 2222 along the radial direction, and the exhaust holes 2222 are communicated with the through hole 2221. In this way, when the single crystal furnace 100 is in use, the air pressure in the first section 221 and the third section 223 expands, flows into the through hole 2221 of the second section 222, and is discharged through the exhaust holes 2222 to ensure the safety of use during thermal expansion.

[0059] Embodiment Nine

[0060] Among them, in order to ensure the structural strength of the entire electrode mounting seat 22, the aperture of the first mounting hole 2211 and the aperture of the second mounting hole 2231 are both larger than the aperture of the through hole 2221, that is, it is only necessary to set the through hole 2221 in the second section 222 to enable air flow. By setting the through hole 2221 with a smaller aperture, the second section 222 can be made as close to a solid state as possible, thereby ensuring the structural strength of the entire electrode mounting seat 22.

[0061] Among them, the aperture of the first mounting hole 2211 and the aperture of the second mounting hole 2231 can be the same or different, and this is not limited here.

[0062] Embodiment Ten

[0063] In order to further ensure the safety of use during thermal expansion, the first section 221 is provided with a first annular notch 2212 at the end of the first mounting hole 2211 facing the second section 222, and the aperture of the first annular notch 2212 is larger than the aperture of the first mounting hole 2211; and / or the third section 223 is provided with a second annular notch 2232 at the end of the second mounting hole 2231 facing the second section 222, and the diameter of the second annular notch 2232 is larger than the aperture of the second mounting hole 2231. Thus, by setting the larger-aperture first annular notch 2212 and / or the second annular notch 2232, when the gas in the first mounting hole 2211 and the second mounting hole 2231 expands, it can flow and expand into the first annular notch 2212 or the second annular notch 2232 with a larger aperture. The first annular notch 221 and the second annular notch 2232 achieve the effect of releasing pressure, and then expand into the through hole 2221, further ensuring the safety of use of the electrode mounting seat 22.

[0064] That is, in this embodiment, the first annular notch 2212 can be provided only at the end of the first mounting hole 2211, or the second annular notch 2232 can be provided only at the end of the second mounting hole 2231, or annular notches can be provided at the ends of both the first mounting hole 2211 and the second mounting hole 2231, all of which can achieve the effect of releasing gas pressure.

[0065] Furthermore, the apertures of the first annular notch 2212 and the second annular notch 2232 are relatively large, resulting in a thinner wall thickness at the set positions of the electrode mounting seat 22. Therefore, the lengths of the first annular notch 2212 and the second annular notch 2232 along the axial direction of the electrode mounting seat 22 are much smaller than the lengths of the first mounting hole 2211 and the second mounting hole 2231, thereby ensuring the structural strength of the electrode mounting seat 22.

[0066] In the above single crystal furnace 100, by setting the heating main body 21 in a wavy shape, the heating main body 21 can have a greater extended length to achieve the effect of increasing the heat generation amount; the height of each heating main body 21 is set within the range of 120 - 300 mm, so that each heating main body 21 has an appropriate height, avoiding that when the height of the heating main body 21 is set too large, the coverage range of each heating main body 21 on the straight wall 11 is relatively large and it is difficult to precisely control the heating temperature at the required position of the straight wall 11; avoiding that when the height of the heating main body 21 is too small, the number of set heating main bodies 21 is relatively large and the installation cost of the heating structure 20 is increased; setting the height of the lowermost heating main body 21 to be less than the heights of the other heating main bodies 21 can more precisely control the temperature in the area of the arc-shaped corner wall 12; detachably connecting the electrode mounting seat 22 to the heating main body 21 and the electrode 40 respectively, and detachably connecting the electrode 40 to the furnace body 30, the heating main body 21 can be removed from the furnace body 30 to clean the impurities deposited on the surface of the heating main body 21, ensuring that the heat generated by the heating main body 21 in the later stage can be quickly radiated to the pot body 10; by setting the electrode mounting seat 22 to include a first section 221, a second section 222, and a third section 223 connected in sequence, the second section 222 does not need to be connected to the bolt 50 or the electrode 40, and no internal thread needs to be provided, so as to ensure the structural strength of the electrode mounting seat 22; by providing the exhaust hole 2222 and the through hole 2221 communicating with each other on the second section 222, gas can flow out to the environment during thermal expansion, ensuring the use safety; by providing annular notches in the first section 221 and the second section 222 respectively, the effect of releasing a part of the pressure can be achieved during gas thermal expansion, further ensuring the use safety of the electrode mounting seat 22.

[0067] It can be understood that those skilled in the art can, under the guidance of the above embodiments, combine various implementation manners in the above embodiments to obtain technical solutions of various implementation manners.

[0068] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A single crystal furnace, characterized in that, Including: A crucible body capable of moving up and down under the drive of a driving member; A plurality of heating structures, sequentially arranged at intervals in the vertical direction, wound around at least a part of the crucible body, including a heating main body and an electrode mounting seat connected to the heating main body; A furnace body wound around the plurality of heating structures; A plurality of electrodes mounted on the furnace body and respectively connected to the plurality of electrode mounting seats in one-to-one correspondence.

2. The single crystal furnace according to claim 1, characterized in that, The heating main body is in a wavy shape.

3. The single crystal furnace according to claim 1, characterized in that The height range of the heating main body is 50 mm - 260 mm.

4. The single crystal furnace according to claim 1, characterized in that, The height of the heating main body at the lowermost position is less than the height of the remaining heating main bodies.

5. The single crystal furnace according to claim 1, characterized in that, The electrode mounting seats are respectively detachably connected to the heating main body and the electrodes, and the electrodes are detachably connected to the furnace body.

6. The single crystal furnace according to claim 5, characterized in that One end of the electrode mounting seat is connected to the heating main body by a bolt, and the other end of the electrode mounting seat is threadedly connected to the electrode.

7. The single crystal furnace according to claim 6, characterized in that, The electrode mounting seat includes a first section, a second section and a third section connected in sequence. The first section is provided with a first mounting hole, and the inner wall of the first mounting hole is provided with a first internal thread for connecting to the heating main body. The third section is provided with a second mounting hole for connecting to the electrode, and the inner wall of the second mounting hole is provided with a second internal thread for connecting to the electrode.

8. The single crystal furnace according to claim 7, wherein The bolt and the electrode respectively have a distance from one end of the second section; The second section is provided with a through hole extending along the axis, the through hole is respectively communicated with the first mounting hole and the second mounting hole, and the second section is provided with an exhaust hole in the radial direction, and the exhaust hole is communicated with the through hole.

9. The single crystal furnace according to claim 8, wherein, The aperture of the first mounting hole and the aperture of the second mounting hole are both larger than the aperture of the through hole.

10. The single crystal furnace according to claim 8, characterized in that, The first section is provided with a first annular notch at the end of the first mounting hole facing the second section, and the aperture of the first annular notch is larger than the aperture of the first mounting hole; and / or the third section is provided with a second annular notch at the end of the second mounting hole facing the second section, and the aperture of the second annular notch is larger than the aperture of the second mounting hole.

Images