Single crystal furnace

Abstract

The utility model relates to a single crystal furnace, which comprises a furnace body, a furnace cover and a furnace cover, the crucible assembly is arranged in the inner cavity of the furnace body, the crucible assembly comprises a quartz crucible and a graphite crucible which are arranged in a sleeved mode, and a silicon solution is contained in the quartz crucible; the heating parts are arranged on the periphery of the crucible assembly and used for heating the crucible assembly; the supporting shaft is connected to the bottom of the graphite crucible in a supporting manner; the monitoring structure is arranged at the top of the furnace body and is used for identifying unmelted polycrystalline silicon in the silicon melt and acquiring the position information of the unmelted polycrystalline silicon; and the movement control structure is arranged at one end, far away from the crucible, of the supporting shaft, and is used for controlling the crucible assembly to move according to the position information of the unmelted polycrystalline silicon and reducing the distance between the unmelted polycrystalline silicon and the heating part. And local heat is increased, so that melting of polycrystalline silicon is accelerated.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor product manufacturing technology, and in particular to a single crystal furnace. Background Technology

[0002] In recent years, photovoltaic power generation, as a green energy source and a major energy source for human sustainable development, has received increasing attention and vigorous development from countries around the world. Monocrystalline silicon wafers, as a fundamental material for photovoltaic power generation, have a wide market demand. Monocrystalline silicon wafers are typically obtained by slicing monocrystalline silicon rods; therefore, the quality of the monocrystalline silicon rods ultimately affects the quality of the silicon wafers. In practical applications, the Czochralski (CZ) method is currently the main method for pulling monocrystalline silicon rods.

[0003] In the production of single-crystal silicon rods, polycrystalline silicon is filled into a quartz crucible, melted, and single-crystal rods are grown through seed crystallization in contact with the molten surface. However, uneven melting of the polycrystalline silicon within the crucible is a problem. Utility Model Content

[0004] To address the aforementioned technical problems, this invention provides a single-crystal furnace that solves the problem of uneven melting of polycrystalline silicon.

[0005] To achieve the above objectives, the technical solution adopted in this embodiment of the utility model is: a single crystal furnace, comprising:

[0006] Furnace body, wherein a chamber is defined within the furnace body;

[0007] A crucible assembly is disposed in the inner cavity of the furnace body. The crucible assembly includes a nested quartz crucible and a graphite crucible, and the quartz crucible contains a silicon solution.

[0008] A heating element is disposed around the crucible assembly for heating the crucible assembly;

[0009] A support shaft is provided for connection to the bottom of the graphite crucible.

[0010] A monitoring structure is installed on the top of the furnace body to identify unmelted polysilicon in the molten silicon and obtain the location information of the unmelted polysilicon.

[0011] A movement control structure is located at the end of the support shaft away from the crucible, and is used to control the movement of the crucible assembly based on the position information of the unmelted polysilicon, thereby reducing the distance between the unmelted polysilicon and the heating element.

[0012] Optionally, the monitoring structure includes:

[0013] The image acquisition unit is used to acquire images of the surface of the molten silicon in real time;

[0014] The location information acquisition unit is used to acquire the location information of unmelted polycrystalline silicon based on the image acquired by the image acquisition unit.

[0015] Optionally, the movement control structure includes:

[0016] The first moving unit includes a first base, a first platform movably disposed on the first base, and a first driving part that drives the first platform to move in a first direction, wherein the first platform is connected to the support shaft.

[0017] The second moving unit includes a second base, a second platform movably disposed on the second base, and a second driving unit that drives the second platform to move in a second direction, wherein the first base is disposed on the second platform;

[0018] The first direction and the second direction are intersecting.

[0019] Optionally, the first drive unit includes a first drive motor and a first lead screw, the first lead screw is connected to the first platform through a transmission connector, and the extension direction of the first lead screw is parallel to the first direction;

[0020] The first lead screw rotates under the drive of the first drive motor, so that the first platform moves in the first direction.

[0021] Optionally, the second drive unit includes a second drive motor and a second lead screw, the second lead screw being connected to the second platform via a transmission connector, and the extension direction of the second lead screw being parallel to the second direction;

[0022] The second lead screw rotates under the drive of the second drive motor, so that the second platform moves in the second direction.

[0023] Optionally, a drive track is provided between the first platform and the first base.

[0024] Optionally, a drive track is provided between the second platform and the second base.

[0025] Optionally, the area of ​​the orthographic projection of the first base onto the second platform is located within the second platform.

[0026] Optionally, the motion control structure further includes:

[0027] The processing unit is used to receive the position information transmitted by the monitoring structure and output control commands to control the movement of the crucible assembly;

[0028] The control commands include the movement trajectory and movement distance of the crucible assembly, and the maximum distance the crucible assembly moves along the first direction or the second direction is less than the distance between the crucible assembly and the heating element.

[0029] Optionally, the heating element is fixed to the bottom of the furnace body by electrode bolts and connected to the heating electrode at the bottom of the furnace body.

[0030] The beneficial effects of this invention are as follows: The single-crystal furnace provided by this invention is equipped with a monitoring structure and a movement control structure. The monitoring structure is used to identify unmelted polysilicon in the molten silicon and obtain the position information of the unmelted polysilicon. The movement control structure is used to control the movement of the crucible assembly based on the position information of the unmelted polysilicon, thereby reducing the distance between the unmelted polysilicon and the heating element. That is, after the monitoring structure detects unmelted polysilicon in the molten silicon and obtains its position information, the movement control structure controls the crucible assembly carrying the molten silicon to move according to the position information, so that the unmelted polysilicon moves closer to the heating element, thereby increasing the local heat and accelerating the melting of the polysilicon. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the single crystal furnace in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram illustrating the motion control structure in an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0034] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0035] The features such as "parallel," "perpendicular," and "identical" used in the embodiments of this disclosure include features in the strict sense of "parallel," "perpendicular," and "identical," as well as cases where "approximately parallel," "approximately perpendicular," and "approximately identical" include certain tolerances. Taking into account the measurement and the tolerances associated with the measurement of a specific quantity (e.g., limitations of the measurement system), they represent the acceptable deviation range for a specific value as determined by a person skilled in the art. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of said value.

[0036] Furthermore, throughout this document, unless otherwise defined, the terms “substantially,” “essentially,” “approximately,” and “about” are used to describe and explain small variations. When used with an event or situation, these terms can cover situations where the event or situation occurs precisely or approximately. For example, when used with a numerical value, these terms can include a range of variation of the numerical value less than or equal to 10%, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term “substantially coplanar” can refer to two surfaces arranged along the same plane within a micrometer range, for example, within 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm.

[0037] refer to Figure 1 and Figure 2 This embodiment provides a single crystal furnace, including:

[0038] Furnace body 1, wherein a chamber is defined within the furnace body 1;

[0039] The crucible assembly 2 is disposed in the inner cavity of the furnace body 1. The crucible assembly 2 includes a quartz crucible 21 and a graphite crucible 22, which are nested together. The quartz crucible 21 contains a silicon solution.

[0040] Heating components 3 are disposed around the crucible assembly 2 and are used to heat the crucible assembly 2;

[0041] A support shaft 4 is connected to the bottom of the graphite crucible 22. A crucible tray is provided at the upper end of the support shaft 4, and the lower end of the support shaft 4 extends out of the bottom of the furnace body 1.

[0042] A monitoring structure is installed on the top of the furnace body to identify unmelted polysilicon in the molten silicon and obtain the location information of the unmelted polysilicon.

[0043] A movement control structure is provided at the end of the support shaft 4 away from the crucible, and is used to control the movement of the crucible assembly 2 according to the position information of the unmelted polysilicon, so as to reduce the distance between the unmelted polysilicon and the heating component 3.

[0044] After the monitoring structure detects unmelted polysilicon in the molten silicon, it acquires the position information of the unmelted polysilicon. The movement control structure controls the crucible assembly 2 carrying the molten silicon to move according to the position information, so that the unmelted polysilicon moves closer to the heating component 3, thereby increasing the local heat and accelerating the melting of polysilicon, which helps to improve the uniformity of polysilicon melting.

[0045] In an exemplary embodiment, the monitoring structure includes:

[0046] Image acquisition unit 100 is used to acquire images of the surface of molten silicon in real time;

[0047] The location information acquisition unit is used to acquire the location information of unmelted polycrystalline silicon based on the image acquired by the image acquisition unit 100.

[0048] For example, the image acquisition unit 100 may include a CCD camera to acquire images of the surface of the molten silicon in real time.

[0049] For example, the location information acquisition unit is used to establish a coordinate system with the center point of the silicon melt as the origin based on the image acquired by the image acquisition unit 100, and to acquire the coordinates of the unmelted polycrystalline silicon.

[0050] It should be noted that the unmelted polysilicon may be a dispersed block structure or multiple polysilicon blocks stacked together. For dispersed polysilicon blocks, the coordinates of each block can be obtained separately. For stacked polysilicon blocks, the center point of the stacked blocks can be selected as the reference coordinate.

[0051] In an exemplary embodiment, the motion control structure includes:

[0052] The first moving unit 6 includes a first base 62, a first platform 61 movably disposed on the first base 62, and a mechanism for driving the first platform 61 in a first direction (see reference). Figure 2 The first driving part moves in the X direction (in the middle), the first platform 61 is connected to the support shaft 4, and the support shaft 4 is connected to the first platform 61 through the base 41;

[0053] The second moving unit 7 includes a second base 72, a second platform 71 movably disposed on the second base 72, and a mechanism for driving the second platform 71 in a second direction (see reference). Figure 2 The second drive unit moves in the Y direction (in the middle), and the first base 62 is disposed on the second platform 71;

[0054] The first direction and the second direction are intersecting.

[0055] In an exemplary embodiment, the first direction and the second direction are arranged perpendicularly, but this is not a limitation.

[0056] It should be noted that the support shaft 4 and the first platform 61 can be detachably connected together. The support shaft 4 and the first platform 61 move synchronously, so that when the first platform 61 moves along the first direction, it synchronously drives the support shaft 4 to move in the first direction, thereby realizing the movement of the crucible assembly 2 in the first direction.

[0057] The first base 62 and the second platform 71 can be detachably connected or fixedly connected. The first base 62 and the second platform 71 move synchronously so that when the second platform 71 moves along the second direction, it synchronously drives the first base 62 and the first platform 61 on it to move in the second direction, thereby further realizing the movement of the crucible assembly 2 in the first direction.

[0058] In an exemplary embodiment, the single crystal furnace further includes a rotation control structure for controlling the rotation of the crucible assembly 2. The rotation control structure can be connected to the second base 72 via a rotation shaft. When the position of the unmelted polycrystalline silicon deviates from the first direction and the second direction, i.e., it is not on the movement path of the crucible assembly 2 along the first direction or the second direction, the rotation control structure can be used to control the rotation of the crucible assembly 2 so that the unmelted polycrystalline silicon is located on the movement path of the crucible assembly 2, thereby effectively reducing the distance between the unmelted polycrystalline silicon and the heating element 3 after the crucible assembly 2 moves along the first direction or the second direction.

[0059] It should be noted that when the rotation control structure controls the crucible assembly 2 to rotate, the first moving unit 6 and the second moving unit 7 rotate synchronously.

[0060] In an exemplary embodiment, the first drive unit includes a first drive motor 81 and a first lead screw 82. The first lead screw 82 is connected to the first platform 61 through a transmission connector 20, and the extension direction of the first lead screw 82 is parallel to the first direction.

[0061] The first lead screw 82 rotates under the drive of the first drive motor 81, so that the first platform 61 moves in the first direction.

[0062] One end of the transmission connector 20 is spirally mounted on the first lead screw 82, and the other end of the transmission connector 20 is connected to the side of the first platform 61 by a connecting bolt. One end of the first lead screw 82 is connected to the first drive motor 81, and the other end of the first lead screw 82 is connected to a lead screw fixing bearing 10. The first drive motor 81 drives the first lead screw 82 to rotate, so that the transmission connector 20 drives the first platform 61 to move linearly in the extension direction of the first lead screw 82.

[0063] In an exemplary embodiment, a transmission track is provided between the first platform 61 and the first base 62 to achieve a movable connection between the first platform 61 and the first base 62. However, this is not a limitation. For example, the first platform 61 and the first base 62 can also be movablely connected by a slide rail and a slider.

[0064] In an exemplary embodiment, the orthographic projection of the first platform 61 onto the first base 62 is located within the first base 62, that is, the area of ​​the first platform 61 is less than or equal to the area of ​​the first base 62, so that the first platform 61 can move smoothly within the first base 62.

[0065] In an exemplary embodiment, the second drive unit includes a second drive motor 91 and a second lead screw 92. The second lead screw 92 is connected to the second platform 71 via a transmission connector 20, and the extension direction of the second lead screw 92 is parallel to the second direction.

[0066] The second lead screw 92 rotates under the drive of the second drive motor 91, so that the second platform 71 moves in the second direction.

[0067] One end of the transmission connector 20 is screwed onto the second lead screw 92, and the other end of the transmission connector 20 is connected to the side of the second platform 71 by a connecting bolt. One end of the second lead screw 92 is connected to the second drive motor 91, and the other end of the second lead screw 92 is connected to a lead screw fixing bearing 10. The second drive motor 91 drives the second lead screw 92 to rotate, so that the transmission connector 20 drives the second platform 71 to move linearly in the extension direction of the second lead screw 92.

[0068] In an exemplary embodiment, a drive track is provided between the second platform 71 and the second base 72 (see reference). Figure 1 The transmission track 73 in the middle is used to realize the movable connection between the second platform 71 and the second base 72, but it is not limited to this. For example, the second platform 71 and the second base 72 can also be movablely connected by a slide rail and a slider.

[0069] In an exemplary embodiment, the orthographic projection of the second platform 71 onto the second base 72 is located within the second base 72, that is, the area of ​​the second platform 71 is less than or equal to the area of ​​the second base 72, so that the second platform 71 can move smoothly within the second base 72.

[0070] In an exemplary embodiment, the area of ​​the orthographic projection of the first base 62 onto the second platform 71 is located within the second platform 71. That is, the area of ​​the first base 62 is less than or equal to the area of ​​the second platform 71.

[0071] In an exemplary embodiment, the motion control structure further includes:

[0072] The processing unit is used to receive the position information transmitted by the monitoring structure and output control commands to control the movement of the crucible assembly 2;

[0073] The control commands include the movement trajectory and movement distance of the crucible assembly 2, and the maximum distance that the crucible assembly 2 moves along the first direction or the second direction is less than the distance between the crucible assembly 2 and the heating element 3.

[0074] The image acquisition unit 100 acquires an image of the surface of the molten silicon. The position information acquisition unit acquires the position information of the unmelted polysilicon based on the image acquired by the image acquisition unit 100, and establishes a coordinate system with the center point M of the molten silicon as the origin. The position information of the unmelted polysilicon is converted into coordinate output, for example, the coordinates (X1, Y1) of the monitored unmelted polysilicon are transmitted to the motion control structure.

[0075] The processing unit of the motion control structure obtains the movement trajectory and movement distance of the crucible assembly 2 using the (X1,Y1) coordinates.

[0076] It should be noted that because the distance between the crucible assembly 2 and the heating element 3 is limited, the moving distance of the crucible assembly 2 is also limited. The maximum distance the crucible assembly 2 can move along the first direction or the second direction is less than the distance between the crucible assembly 2 and the heating element 3, to avoid contact between the crucible assembly 2 and the heating element 3. That is, the distance between the crucible assembly 2 and the heating element 3 must be kept greater than zero. Therefore, the moving distance is obtained by proportionally converting the coordinates of the unmelted polycrystalline silicon. For example, the coordinates (X1, Y1) of the unmelted polycrystalline silicon are used as the moving distance (X2, Y2) of the crucible assembly 2, and the position of the crucible assembly 2 is moved according to the coordinates (X2, Y2). The coordinates (X2, Y2) have a maximum value limit to maintain the distance between the crucible assembly 2 and the heating element 3, preventing the crucible assembly 2 from directly contacting the heating element 3.

[0077] It should be noted that the maximum moving distance of the crucible assembly 2 can be set according to actual needs. For example, the minimum distance between the crucible assembly 2 and the heating element 3 is 0.1-0.5 mm, but it is not limited to this.

[0078] In an exemplary embodiment, the heating element 3 is disposed around the crucible assembly 2 for heating the crucible assembly 2. The heating element 3 is fixed to the bottom of the furnace body 1 by electrode bolts and is connected to the heating electrode at the bottom of the furnace body 1.

[0079] In an exemplary embodiment, the single crystal furnace further includes a heat insulation layer disposed between the heating element 3 and the side wall of the furnace body 1, for blocking the heat of the heating element 3 from radiating to the outside of the furnace body 1.

[0080] The following points need to be explained:

[0081] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0082] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present disclosure, i.e., these drawings are not drawn to actual scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0083] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0084] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

Claims

1. A single crystal furnace, characterized in that, include: Furnace body, wherein a chamber is defined within the furnace body; A crucible assembly is disposed in the inner cavity of the furnace body. The crucible assembly includes a nested quartz crucible and a graphite crucible, and the quartz crucible contains a silicon solution. A heating element is disposed around the crucible assembly for heating the crucible assembly; A support shaft is provided for connection to the bottom of the graphite crucible. A monitoring structure is installed on the top of the furnace body to identify unmelted polysilicon in the molten silicon and obtain the location information of the unmelted polysilicon. A movement control structure is located at the end of the support shaft away from the crucible, and is used to control the movement of the crucible assembly based on the position information of the unmelted polysilicon, thereby reducing the distance between the unmelted polysilicon and the heating element.

2. The single crystal furnace according to claim 1, characterized in that, The monitoring structure includes: The image acquisition unit is used to acquire images of the surface of the molten silicon in real time; The location information acquisition unit is used to acquire the location information of unmelted polycrystalline silicon based on the image acquired by the image acquisition unit.

3. The single crystal furnace according to claim 1, characterized in that, The movement control structure includes: The first moving unit includes a first base, a first platform movably disposed on the first base, and a first driving part that drives the first platform to move in a first direction, wherein the first platform is connected to the support shaft. The second moving unit includes a second base, a second platform movably disposed on the second base, and a second driving unit that drives the second platform to move in a second direction, wherein the first base is disposed on the second platform; The first direction and the second direction are intersecting.

4. The single crystal furnace according to claim 3, characterized in that, The first drive unit includes a first drive motor and a first lead screw. The first lead screw is connected to the first platform through a transmission connector, and the extension direction of the first lead screw is parallel to the first direction. The first lead screw rotates under the drive of the first drive motor, so that the first platform moves in the first direction.

5. The single crystal furnace according to claim 3, characterized in that, The second drive unit includes a second drive motor and a second lead screw. The second lead screw is connected to the second platform through a transmission connector, and the extension direction of the second lead screw is parallel to the second direction. The second lead screw rotates under the drive of the second drive motor, so that the second platform moves in the second direction.

6. The single crystal furnace according to claim 3, characterized in that, A transmission track is provided between the first platform and the first base.

7. The single crystal furnace according to claim 3, characterized in that, A drive track is provided between the second platform and the second base.

8. The single crystal furnace according to claim 3, characterized in that, The area of ​​the orthographic projection of the first base onto the second platform lies within the second platform.

9. The single crystal furnace according to claim 3, characterized in that, The motion control structure also includes: The processing unit is used to receive the position information transmitted by the monitoring structure and output control commands to control the movement of the crucible assembly; The control commands include the movement trajectory and movement distance of the crucible assembly, and the maximum distance the crucible assembly moves along the first direction or the second direction is less than the distance between the crucible assembly and the heating element.

10. The single crystal furnace according to claim 1, characterized in that, The heating element is fixed to the bottom of the furnace body by electrode bolts and is connected to the heating electrode at the bottom of the furnace body.

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