A single crystal furnace and a secondary feeding method

Abstract

The present disclosure provides a single crystal furnace and a secondary feeding method. The single crystal furnace comprises a furnace body comprising a furnace chamber, and at least one set of stop block mechanisms, each set of the stop block mechanisms comprising a stop block and a lifting unit, the stop block being arranged on an inner circumferential wall of the furnace chamber, and the stop block being connected to the lifting unit and being capable of moving axially along the furnace chamber under the driving of the lifting unit. The single crystal furnace and the secondary feeding method provided by the embodiments of the present disclosure can flexibly adjust the height of the feeding pipe during the feeding process of the feeding pipe.

Description

Technical Field

[0001] This invention relates to the field of crystal pulling technology, and in particular to a single crystal furnace and a secondary feeding method. Background Technology

[0002] A single-crystal furnace is a specialized piece of equipment for producing single-crystal silicon rods. In traditional production, polycrystalline silicon raw materials are loaded into a quartz crucible and melted all at once. The effective mass of the single-crystal silicon rod is limited by the maximum feed rate, which is determined by the size of the quartz crucible. The weight of the blocky silicon material filling the crucible is the maximum feed rate. During the melting process, the blocky solid silicon turns into liquid, releasing the space occupied by the gaps between the blocks. A single-feed operation cannot achieve a sufficient quantity of material, thus reducing the maximum feed rate and resulting in low crucible utilization. Therefore, secondary feeding technology is widely used to improve crucible utilization and reduce costs.

[0003] In related technologies, a typical secondary feeding system is widely used, implemented through a feeding tube. The feeding tube mainly consists of a guide device, a tube body, a central molybdenum rod, and a conical base. The top of the central molybdenum rod connects to the lifting head of the single crystal furnace, and the bottom connects to the conical base via screws. The central molybdenum rod passes through the tube body and the guide device, and the bottom of the tube body and the conical base close together to form a space for storing silicon. The feeding tube needs to be positioned and limited by a stop at a corresponding location within the single crystal furnace. Then, the lifting head descends, the conical base gradually separates from the tube body, and the silicon falls, thus completing the feeding process.

[0004] However, conventional feeding methods have certain limitations: the baffle used to position and limit the feeding tube cannot be moved. As feeding proceeds, the silicon liquid level will rise and get closer and closer to the feeding tube. Splashing and high temperature will damage the feeding tube, so the feeding amount can only be reduced. If the feeding amount needs to be increased, the height of the baffle must be increased, which inevitably leads to more severe solution splashing in the early stage of feeding, which may damage the heater and the hot zone, and also reduce the service life of the guide tube.

[0005] Some technologies have designed telescopic quartz feeding devices that can move the feeding tube. However, this solution requires redesigning the feeding tube, which is more complex in structure, has higher replacement and maintenance costs, and has a large overall radial dimension, making it difficult to implement in a long and narrow furnace chamber. Furthermore, it cannot be adjusted in real time and requires the feeding tube to be removed for adjustment, which also has certain limitations. Summary of the Invention

[0006] This disclosure provides a single crystal furnace and a secondary feeding method, which can flexibly adjust the height of the feeding tube during the feeding process.

[0007] The technical solution provided by this invention is as follows:

[0008] A single crystal furnace, comprising:

[0009] Furnace body, including furnace chamber; and

[0010] At least one set of stop mechanisms, each set of stop mechanisms including a stop block and a lifting unit, the stop block being disposed on the inner peripheral wall of the furnace chamber and connected to the lifting unit, and being able to move along the axial direction of the furnace chamber under the drive of the lifting unit.

[0011] For example, there are at least two sets of the stop mechanism, and the at least two sets of the stop mechanism are distributed circumferentially along the inner peripheral wall of the furnace chamber.

[0012] For example, the inner peripheral wall of the furnace chamber is provided with a sliding groove extending along the axial direction of the furnace chamber, the side wall of the furnace chamber is also provided with an installation cavity communicating with the sliding groove, and the side wall of the furnace chamber is also provided with a radial channel that radially penetrates the installation cavity and the outer peripheral wall of the furnace chamber.

[0013] The lifting unit includes a transmission assembly and a drive assembly. The stop block is disposed corresponding to the slide groove. The drive assembly is at least partially exposed outside the furnace chamber and is connected to the transmission assembly via the radial channel. The transmission assembly is installed in the mounting cavity and is connected to the stop block via the slide groove. The drive assembly drives the stop block to move axially along the furnace chamber through the transmission assembly.

[0014] For example, the transmission assembly includes a lead screw assembly, the lead screw assembly comprising:

[0015] A lead screw is arranged axially along the furnace chamber, the lead screw having a first end and a second end opposite each other along its own axial direction; and

[0016] A slider, which is connected to the lead screw and can move along the lead screw as the lead screw rotates;

[0017] The drive component is directly or indirectly connected to the lead screw to drive the lead screw to rotate, and the stop block is connected to the slider to move synchronously with the slider.

[0018] For example, the drive assembly includes a rotating shaft and a drive member. The rotating shaft extends radially along the furnace chamber and passes through the radial channel. The rotating shaft has a third end and a fourth end opposite to each other along its own axial direction. The third end is placed in the mounting cavity, and the fourth end extends to the outer side of the outer peripheral wall of the furnace body. The fourth end is connected to the drive member.

[0019] The transmission assembly further includes a bevel gear transmission group, which connects the second end of the lead screw to the third end of the rotating shaft, and is used to convert the rotational motion of the rotating shaft about its own axis into the rotational motion of the lead screw about its own axis.

[0020] For example, the drive component may include a handwheel or a drive motor.

[0021] For example, the bevel gear transmission assembly includes:

[0022] A first bevel gear, which is coaxially connected to the second end of the lead screw;

[0023] A second bevel gear, which is coaxially connected to the third end of the rotating shaft;

[0024] The first bevel gear and the second bevel gear mesh with each other.

[0025] For example, the outer diameter of the first bevel gear is less than or equal to the outer diameter of the second bevel gear.

[0026] For example, the mounting cavity includes a first chamber extending axially along the furnace chamber and a second chamber separated from the first chamber, wherein the first chamber communicates with the slide groove, the lead screw assembly is mounted in the slide groove, the second end of the lead screw extends from the first chamber to the second chamber, the third end of the rotating shaft extends from outside the furnace chamber to the second chamber, and the bevel gear transmission assembly is mounted in the second chamber.

[0027] A secondary feeding method for a single crystal furnace, applied to the single crystal furnace described above, the method comprising the following steps:

[0028] During the secondary feeding process into the single crystal furnace through the feeding pipe, the feeding pipe is positioned and limited by the stop block, and the stop block is moved along the axial direction of the furnace chamber according to a predetermined rule to adjust the relative distance between the feeding pipe and the crucible in the furnace chamber along the axial direction of the furnace chamber.

[0029] The beneficial effects of the embodiments disclosed herein are as follows:

[0030] In the above scheme, the baffle used to position and limit the feeding tube inside the single crystal furnace is designed to move freely along the furnace chamber axis. Because the baffle can move freely along the furnace chamber axis, the distance between the feeding tube and the liquid surface in the crucible is adjustable, ensuring sufficient feeding amount each time and guaranteeing the safety of the heater, hot zone, and feeding tube. Furthermore, since the distance between the feeding tube and the liquid surface can be adjusted according to actual conditions, it can better cope with various emergencies and ensure equipment safety. In addition, only structural modifications to the baffle are needed to achieve its lifting purpose, resulting in a simple structure and convenient operation. Moreover, when pulling multiple crystal rods, the height of the baffle can be directly adjusted, allowing free switching between single and multiple rod pulling without being limited by other external factors. In summary, macroscopically, this increases the output of the single crystal furnace in a single cycle, the utilization rate of the quartz crucible, and reduces the manufacturing cost of single crystal preparation. Attached Figure Description

[0031] Figure 1 This is a view showing the appearance of the single crystal furnace in an embodiment of this disclosure;

[0032] Figure 2 This is a cross-sectional view of the single crystal furnace in an embodiment of this disclosure;

[0033] Figure 3 express Figure 2 Enlarged view of the partial structure within the dashed box A in the middle. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] like Figures 1 to 3 As shown, the single crystal furnace provided in this embodiment of the invention includes a furnace body 10 and at least one set of baffle mechanisms 20. The furnace body 10 includes a furnace chamber, and a crucible, a crucible shaft, a heater, etc., may be disposed within the furnace chamber;

[0037] Each set of the stop mechanism 20 includes a stop 21 and a lifting unit 22. The stop 21 is disposed on the inner peripheral wall of the furnace chamber and is connected to the lifting unit 22. Under the drive of the lifting unit 22, the stop 21 can move along the axial direction of the furnace chamber.

[0038] In the above scheme, the stop 21 used for positioning and limiting the feeding tube in the single crystal furnace is designed to be freely movable along the furnace chamber axis. Because the stop 21 can move freely along the furnace chamber axis, the distance between the feeding tube and the liquid surface in the crucible is adjustable, ensuring sufficient feeding amount each time and guaranteeing the safety of the heater, hot zone, and feeding tube. Furthermore, since the distance between the feeding tube and the liquid surface can be adjusted according to actual conditions, it can better cope with various emergencies and ensure equipment safety. In addition, only structural modifications to the stop 21 are needed to achieve its lifting purpose, resulting in a simple structure and convenient operation. Moreover, when pulling multiple crystal rods, the height of the stop 21 can be directly adjusted, allowing free switching between single and multiple rod pulling without being limited by other external factors. In summary, macroscopically, this increases the output of the single crystal furnace in a single cycle, the utilization rate of the quartz crucible, and reduces the manufacturing cost of single crystal preparation.

[0039] As an exemplary embodiment, such as Figure 1 and Figure 2 As shown, there may be at least two sets of the stop mechanism 20, and the at least two sets of the stop mechanism 20 are distributed circumferentially along the inner peripheral wall of the furnace chamber. In a more specific embodiment, as... Figure 1 and Figure 2 As shown, there may be two sets of the stop mechanism 20, with the two sets of stop mechanisms 20 symmetrically arranged on the radially opposite side walls of the furnace chamber. It is understood that the specific number of the stop mechanisms 20 is not limited, and there may be two or more sets.

[0040] As some exemplary embodiments, such as Figure 3 As shown, the inner peripheral wall of the furnace chamber is provided with a sliding groove 11 extending along the axial direction of the furnace chamber. The side wall of the furnace chamber is also provided with an installation cavity 12 communicating with the sliding groove 11. The side wall of the furnace chamber is also provided with a radial channel 13 that radially penetrates the installation cavity 12 and the outer peripheral wall of the furnace chamber. The lifting unit 22 includes a transmission assembly 221 and a drive assembly 222. The stop block 21 is provided corresponding to the sliding groove 11. The drive assembly 222 is at least partially exposed outside the furnace chamber and is connected to the transmission assembly 221 via the radial channel 13. The transmission assembly 221 is installed in the installation cavity 12 and is connected to the stop block 21 via the sliding groove 11. The drive assembly 222 drives the stop block 21 to move along the axial direction of the furnace chamber through the transmission assembly 221.

[0041] In the above scheme, the transmission component 221 serves as the power transmission component between the drive component 222 and the stop block 21, and it is responsible for driving the stop block 21 to rise and fall under the power of the drive component 222. The drive component 222 is at least partially exposed outside the furnace room to facilitate operator control of its operation and to change the position of the stop block 21 at any time.

[0042] For example, such as Figure 3 As shown, the transmission assembly 221 includes a lead screw assembly, which includes:

[0043] A lead screw 2211 is arranged axially along the furnace chamber, the lead screw 2211 having a first end and a second end opposite to each other along its own axial direction; and

[0044] Slider 2212 is connected to lead screw 2211 and can move along lead screw 2211 as lead screw 2211 rotates;

[0045] The drive assembly 222 is directly or indirectly connected to the lead screw 2211 to drive the lead screw 2211 to rotate, and the stop block 21 is connected to the slider 2212 to move synchronously with the slider 2212.

[0046] In the above scheme, the transmission component 221 is a set of lead screws 2211. The movement of the slider 2212 on the lead screw 2211 drives the movement of the stop block 21. This method has a simple structure and the movement accuracy of the stop block 21 is high.

[0047] It should be noted that the lead screw 2211 drives the movement of the slider 2212, and the thread of the lead screw 2211 must meet the self-locking condition so that the slider 2212 can be locked to the expected position.

[0048] It is understood that the transmission assembly 221 is not limited to the lead screw 2211 group, but can be any other structure that can drive the stop block 21 to rise and fall.

[0049] In addition, for example, such as Figure 3 As shown, the lead screw assembly also includes a guide rod 2213, and the slider 2212 can move along the guide rod 2213 to improve the smoothness of the stop block's movement.

[0050] In addition, for example, Figure 3 As shown, the drive assembly 222 includes a rotating shaft 2221 and a drive member 2222. The rotating shaft 2221 extends radially along the furnace chamber and passes through the radial channel 13. A bearing is provided between the rotating shaft 2221 and the radial channel 13 to allow the rotating shaft 2221 to rotate freely within the radial channel 13, and the gap between the rotating shaft 2221 and the radial channel 13 is sealed by a bearing cover. The rotating shaft 2221 has a third end and a fourth end opposite to each other along its own axial direction. The third end is placed in the mounting cavity 12, and the fourth end extends to the outer side of the outer peripheral wall of the furnace body 10. The fourth end is connected to the drive member 2222. The transmission assembly 221 further includes a bevel gear transmission group, which connects the second end of the lead screw 2211 and the third end of the rotating shaft 2221 to convert the rotational motion of the rotating shaft 2221 about its own axis into the rotational motion of the lead screw 2211 about its own axis.

[0051] In the above scheme, the driving component 2222 can drive the rotating shaft 2221 to rotate. The rotating shaft 2221 is axially arranged to extend radially along the furnace chamber, while the lead screw 2211 extends axially along the furnace chamber. Therefore, the transmission assembly 221 also adopts a bevel gear transmission group that can transmit vertical rotational motion, so as to change the radial rotational motion of the rotating shaft 2221 into the axial rotational motion of the lead screw 2211, and then convert the rotational motion of the lead screw 2211 into the axial linear motion of the stop block 21. The bevel gear transmission group can also bear a part of the axial force. The speed of the stop block 21 can be controlled by changing the transmission ratio of the bevel gear transmission group.

[0052] For example, the drive component 2222 can be a handwheel for manual operation; the drive component 2222 can also be a drive motor for automated operation.

[0053] Furthermore, as an exemplary embodiment, such as Figure 3 As shown, the bevel gear transmission assembly includes:

[0054] The first bevel gear 223 is coaxially connected to the second end of the lead screw 2211;

[0055] The second bevel gear 224 is coaxially connected to the third end of the rotating shaft 2221;

[0056] The first bevel gear 223 and the second bevel gear 224 mesh with each other.

[0057] For example, the outer diameter of the first bevel gear 223 is less than or equal to the outer diameter of the second bevel gear 224. By employing this scheme, the larger torque of the drive component 2222 can be converted into a smaller torque of the lead screw 2211, thereby achieving more precise adjustment of the height of the stop block 21.

[0058] Furthermore, by way of example, the mounting cavity 12 includes a first chamber 121 extending axially along the furnace chamber and a second chamber 122 separated from the first chamber 121, wherein the first chamber 121 communicates with the slide groove 11, the lead screw 2211 assembly is installed in the slide groove 11, the second end of the lead screw 2211 extends from the first chamber 121 to the second chamber 122, the third end of the rotating shaft 2221 extends from outside the furnace chamber to the second chamber 122, and the bevel gear transmission assembly is installed in the second chamber 122. With the above solution, the second chamber 122 can provide a relatively clean space for the bevel gear transmission assembly to avoid contamination by particles and other impurities, thereby improving its service life.

[0059] Furthermore, this disclosure also provides a secondary feeding method for a single crystal furnace, applied to the single crystal furnace in this disclosure embodiment, the method comprising the following steps:

[0060] During the secondary feeding process into the single crystal furnace through the feeding pipe, the feeding pipe is positioned and limited by the stop 21, and the stop 21 is moved along the axial direction of the furnace chamber according to a predetermined rule to adjust the relative distance between the feeding pipe and the crucible in the furnace chamber along the axial direction of the furnace chamber.

[0061] The following points need to be explained:

[0062] (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.

[0063] (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.

[0064] (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.

[0065] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure shall be determined by the scope of the claims.

Claims

1. A single crystal furnace, characterized in that, include: Furnace body, including furnace chamber; and At least one set of stop mechanisms, each set of stop mechanisms including a stop and a lifting unit, the stop being configured to position and limit the feeding pipe during the secondary feeding process into the single crystal furnace through the feeding pipe, the stop being disposed on the inner peripheral wall of the furnace chamber, and the stop being connected to the lifting unit and being able to move along the furnace chamber axially under the drive of the lifting unit; The inner peripheral wall of the furnace chamber is provided with a sliding groove extending along the axial direction of the furnace chamber. The side wall of the furnace chamber is also provided with an installation cavity communicating with the sliding groove. The side wall of the furnace chamber is also provided with a radial channel that radially penetrates the installation cavity and the outer peripheral wall of the furnace chamber. The lifting unit includes a transmission assembly and a drive assembly. The stop block is disposed corresponding to the slide groove. The drive assembly is at least partially exposed outside the furnace chamber and is connected to the transmission assembly via the radial channel. The transmission assembly is installed in the mounting cavity and is connected to the stop block via the slide groove. The drive assembly drives the stop block to move axially along the furnace chamber through the transmission assembly.

2. The single crystal furnace according to claim 1, characterized in that, The stop mechanism has at least two sets, and the at least two sets of the stop mechanism are distributed circumferentially along the inner peripheral wall of the furnace chamber.

3. The single crystal furnace according to claim 1, characterized in that, The transmission assembly includes a lead screw assembly, the lead screw assembly comprising: A lead screw is arranged axially along the furnace chamber, the lead screw having a first end and a second end opposite each other along its own axial direction; and A slider, which is connected to the lead screw and can move along the lead screw as the lead screw rotates; The drive component is directly or indirectly connected to the lead screw to drive the lead screw to rotate, and the stop block is connected to the slider to move synchronously with the slider.

4. The single crystal furnace according to claim 3, characterized in that, The drive assembly includes a rotating shaft and a drive member. The rotating shaft extends radially along the furnace chamber and passes through the radial channel. The rotating shaft has a third end and a fourth end that are opposite each other along its own axial direction. The third end is placed in the mounting cavity, and the fourth end extends to the outer side of the outer peripheral wall of the furnace body. The fourth end is connected to the drive member. The transmission assembly further includes a bevel gear transmission group, which connects the second end of the lead screw to the third end of the rotating shaft, and is used to convert the rotational motion of the rotating shaft about its own axis into the rotational motion of the lead screw about its own axis.

5. The single crystal furnace according to claim 4, characterized in that, The driving component includes a handwheel or a drive motor.

6. The single crystal furnace according to claim 4, characterized in that, The bevel gear transmission assembly includes: A first bevel gear, which is coaxially connected to the second end of the lead screw; A second bevel gear, which is coaxially connected to the third end of the rotating shaft; The first bevel gear and the second bevel gear mesh with each other.

7. The single crystal furnace according to claim 6, characterized in that, The outer diameter of the first bevel gear is less than or equal to the outer diameter of the second bevel gear.

8. The single crystal furnace according to claim 4, characterized in that, The mounting cavity includes a first chamber extending axially along the furnace chamber and a second chamber separated from the first chamber, wherein the first chamber communicates with the slide groove, the lead screw assembly is installed in the slide groove, the second end of the lead screw extends from the first chamber to the second chamber, the third end of the rotating shaft extends from outside the furnace chamber to the second chamber, and the bevel gear transmission assembly is installed in the second chamber.

9. A method for secondary feeding of a single crystal furnace, characterized in that, Applied to the single crystal furnace as described in any one of claims 1 to 7, the method comprises the following steps: During the secondary feeding process into the single crystal furnace through the feeding pipe, the feeding pipe is positioned and limited by the stop block, and the stop block is moved along the axial direction of the furnace chamber according to a predetermined rule to adjust the relative distance between the feeding pipe and the crucible liquid surface in the furnace chamber along the axial direction of the furnace chamber.

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