TWI853456B - Single crystal furnace and secondary charging method - Google Patents

Abstract

The present invention provides a single crystal furnace and a secondary charging method, the single crystal furnace comprising: a furnace body, which comprises a furnace chamber; and at least one set of baffle mechanisms, each set of the baffle mechanisms comprising a baffle and a lifting unit, the baffle being arranged on the inner circumferential wall of the furnace chamber, and the baffle being connected to the lifting unit, and being able to move axially along the furnace chamber when driven by the lifting unit.

Description

Single crystal furnace and secondary charging method

The present invention belongs to the field of crystal pulling technology, and in particular relates to a single crystal furnace and a secondary charging method.

The single crystal furnace is a professional equipment for producing single crystal silicon rods. In the traditional production process, polycrystalline silicon raw materials are loaded into the quartz crucible at one time for melting and production. The effective quality of the single crystal silicon rod is limited by the maximum feeding amount, which is determined by the size of the quartz crucible. The weight of the block silicon material filled with the quartz crucible is the maximum feeding amount. During the melting process of the silicon material, the block solid silicon becomes liquid, and the space occupied by the gaps between the blocks is released. The one-time feeding cannot achieve sufficient feeding, which reduces the maximum feeding amount to a certain extent, and the crucible utilization rate is not high. Therefore, the secondary feeding technology has been widely used to improve the crucible utilization rate and reduce costs.

In the related technologies, a typical secondary feeding system is widely used, which is realized through a feeding tube. The feeding tube is mainly composed of a guide device, a tube body, a central molybdenum rod and a conical base; the top of the central molybdenum rod can be connected to the single crystal furnace lifting head, and the bottom is connected to the conical base through 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 are closed to form a space for storing silicon materials. The feeding tube needs to be positioned and limited by the block at the corresponding position in the single crystal furnace, and then the lifting head is lowered, the conical base and the tube body are gradually separated, and the silicon material falls to realize the feeding.

However, the conventional feeding method has certain limitations: the baffle used to position and limit the feeding tube cannot be moved. As the feeding progresses, the silicon liquid level will rise and get closer to the feeding tube. The 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 will inevitably cause more severe solution splashing in the initial stage of feeding, which will pose a risk of damaging the heater and the thermal field and reduce the service life of the guide tube.

In some technologies, a telescopic quartz feeding device is designed to realize the movement of the feeding tube, but this solution requires the redesign of the feeding tube, the structure of the feeding tube is more complicated, the replacement and maintenance costs are higher, the radial size of the overall structure is too large, and it is not easy to implement in a narrow and long furnace chamber, etc., and it cannot be adjusted in time. The feeding tube needs to be taken out for adjustment, which also has certain limitations.

The embodiment of the present invention provides a single crystal furnace and a secondary charging method, which can flexibly adjust the height of the charging tube during the charging process of the charging tube.

The technical solution provided by the present invention is as follows: A single crystal furnace, comprising: A furnace body, which includes a furnace chamber; and At least one set of baffle mechanisms, each set of the baffle mechanisms includes a baffle and a lifting unit, the baffle is arranged on the inner peripheral wall of the furnace chamber, and the baffle is connected to the lifting unit, and can move along the axial direction of the furnace chamber when driven by the lifting unit.

Exemplarily, there are at least two groups of the baffle mechanism, and the at least two groups of the baffle mechanism are circumferentially distributed along the inner circumferential wall of the furnace chamber.

For example, the inner peripheral wall of the furnace chamber is provided with a slide groove extending along the axial direction of the furnace chamber, the inner side wall of the furnace chamber is also provided with a mounting cavity communicating with the slide groove, and the side wall of the furnace chamber is also provided with a radial channel radially penetrating the mounting cavity and the outer peripheral wall of the furnace chamber; Wherein, the lifting unit includes a transmission element and a driving element, the block is arranged corresponding to the slide groove, the driving element is at least partially exposed to the outside of the furnace chamber and connected to the transmission element through the radial channel, the transmission element is installed in the mounting cavity and connected to the block through the slide groove, and the driving element drives the block to move axially along the furnace chamber through the transmission element.

Exemplarily, the transmission element includes a screw bar group, which includes: A screw bar arranged along the axial direction of the furnace chamber, the screw bar having a first end and a second end opposite to each other along its own axial direction; and A slider, the slider is connected to the screw bar and can move along the screw bar as the screw bar rotates; Wherein, the driving element is directly or indirectly connected to the screw bar to drive the screw bar to rotate, and the block is connected to the slider to move synchronously with the slider.

Exemplarily, the driving element includes a rotating shaft and a driving member, the rotating shaft extends radially along the furnace chamber and penetrates the radial channel, the rotating shaft has a third end and a fourth end opposite to each other along its own axis, the third end is placed in the mounting cavity, the fourth end extends to the outer side of the outer peripheral wall of the furnace body, and the fourth end is connected to the driving member; The transmission element also includes: a tapered gear transmission group, the tapered gear transmission group connects the second end of the lead screw and the third end of the rotating shaft, and is used to convert the rotational motion of the rotating shaft around its own axis into the rotational motion of the lead screw around its own axis.

Exemplarily, the drive member includes a handwheel or a drive motor.

Exemplarily, the bevel gear transmission group includes: A first bevel gear, the first bevel gear is coaxially connected to the second end of the screw; A second bevel gear, the second bevel gear is coaxially connected to the third end of the rotating shaft; Wherein, the bevel gears of the first bevel gear and the second bevel gear are meshed with each other.

Exemplarily, the outer diameter of the gear of the first bevel gear is smaller than or equal to the outer diameter of the gear of the second bevel gear.

Exemplarily, the mounting cavity includes a first chamber extending along the axial direction of the furnace chamber and a second chamber separated from the first chamber, wherein the first chamber is connected to the slide groove, the screw lever assembly is installed in the slide groove, the second end of the screw lever extends from the first chamber to the second chamber, the third end of the rotating shaft extends from the outside of the furnace chamber to the second chamber, and the tapered gear transmission assembly is installed in the second chamber.

A secondary charging method for a single crystal furnace is applied to the single crystal furnace as described above, and the method comprises the following steps: In the process of secondary charging into the single crystal furnace through a charging tube, the charging tube is positioned and limited by the baffle, and the baffle is moved along the axial direction of the furnace chamber according to a predetermined rule to adjust the relative distance between the charging tube and the crucible in the furnace chamber in the axial direction of the furnace chamber.

The beneficial effects brought by the embodiment of the present invention are as follows: In the above scheme, the baffle used for positioning and limiting the feeding tube in the single crystal furnace is designed to be a structure that can move freely along the axial direction of the furnace chamber. In this way, since the baffle can move freely along the axial direction of the furnace chamber, the distance between the feeding tube and the liquid surface of the crucible can be adjusted, thereby ensuring that the amount of feeding each time is sufficient and the safety of the heater, thermal field and feeding tube can be ensured; and, by The distance between the feeding tube and the liquid surface can be adjusted according to the actual situation, which can better cope with various emergencies and ensure the safety of the equipment. In addition, only the structure of the baffle needs to be improved to achieve its lifting purpose, with a simple structure and convenient operation. In addition, when pulling multiple crystal rods, the height of the baffle can be directly adjusted, and the pulling of a single rod and multiple rods can be switched freely without being restricted by other external factors. In summary, from a macro perspective, the output of the single crystal furnace in a single cycle and the utilization rate of the quartz crucible are improved, and the manufacturing cost of preparing single crystals is reduced.

In order to help you understand the technical features, contents and advantages of the present invention and the effects it can achieve, the present invention is described in detail as follows with the accompanying drawings and appendices in the form of embodiments. The drawings used therein are only for illustration and auxiliary description, and may not be the true proportions and precise configurations after the implementation of the present invention. Therefore, the proportions and configurations of the attached drawings should not be interpreted to limit the scope of application of the present invention in actual implementation.

In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present 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 number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention.

As shown in Figures 1 to 3, the single crystal furnace provided by the embodiment of the present invention includes a furnace body 10 and at least one set of baffle mechanisms 20. The furnace body 10 includes a furnace chamber, in which a crucible, a crucible shaft, a heater, etc. may be arranged; Each set of the baffle mechanisms 20 includes a baffle 21 and a lifting unit 22, the baffle 21 is arranged on the inner peripheral wall of the furnace chamber, and the baffle 21 is connected to the lifting unit 22, and can move along the axial direction of the furnace chamber when driven by the lifting unit 22.

In the above scheme, the baffle 21 used for positioning and limiting the feeding tube in the single crystal furnace is designed to be a structure that can move freely along the axial direction of the furnace chamber. In this way, since the baffle 21 can move freely along the axial direction of the furnace chamber, the distance between the feeding tube and the liquid surface of the crucible can be adjusted, thereby ensuring that the amount of feeding each time is sufficient and the safety of the heater, the thermal field and the feeding tube can be ensured; and, The distance between the feeding tube and the liquid surface can be adjusted according to the actual situation, which can better cope with various emergencies and ensure the safety of the equipment. In addition, only the structure of the block 21 needs to be improved to achieve its lifting purpose, and the structure is simple and easy to operate. In addition, when pulling multiple crystal rods, the height of the block 21 can be directly adjusted, and the pulling of a single rod and multiple rods can be switched freely without being restricted by other external factors. In summary, from a macro perspective, the output of the single crystal furnace in a single cycle and the utilization rate of the quartz crucible are improved, and the manufacturing cost of preparing single crystals is reduced.

As an exemplary embodiment, as shown in FIG. 1 and FIG. 2 , the block mechanism 20 may have at least two groups, and the at least two groups of the block mechanism 20 are circumferentially distributed along the inner peripheral wall of the furnace chamber. In a more specific embodiment, as shown in FIG. 1 and FIG. 2 , the block mechanism 20 may have two groups, and the two groups of the block mechanism 20 are symmetrically arranged on two radially opposite side walls of the furnace chamber. Of course, it can be understood that the specific number of the block mechanism 20 is not limited, and it can also be two groups or more.

As some exemplary embodiments, as shown in FIG. 3 , a chute 11 extending along the axial direction of the furnace chamber is provided on the inner peripheral wall of the furnace chamber, a mounting cavity 12 communicating with the chute 11 is provided inside the side wall of the furnace chamber, and a radial channel 13 radially penetrating the mounting cavity 12 and the outer peripheral wall of the furnace chamber is provided on the side wall of the furnace chamber; wherein the lifting unit 22 includes a transmission element 221 and a driving element 2 22, the baffle 21 is arranged corresponding to the slide groove 11, the driving element 222 is at least partially exposed to the outside of the furnace chamber and is connected to the transmission element 221 via the radial channel 13, the transmission element 221 is installed in the installation cavity 12 and is connected to the baffle 21 via the slide groove 11, and the driving element 222 drives the baffle 21 to move axially along the furnace chamber through the transmission element 221.

In the above solution, the transmission element 221 serves as a power transmission component between the driving element 222 and the block 21, and is responsible for driving the block 21 to move up and down under the power of the driving element 222. The driving element 222 is at least partially exposed to the outside of the furnace, so that the operator can control its operation and change the position of the block 21 at any time.

Exemplarily, as shown in FIG3 , the transmission element 221 includes a screw bar assembly, which includes: A screw bar 2211 arranged along the axial direction of the furnace chamber, the screw bar 2211 having a first end and a second end opposite to each other along its own axial direction; and A slider 2212, the slider 2212 is connected to the screw bar 2211, and can move along the screw bar 2211 as the screw bar 2211 rotates; The driving element 222 is directly or indirectly connected to the screw lever 2211 to drive the screw lever 2211 to rotate, and the block 21 is connected to the slider 2212 to move synchronously with the slider 2212.

In the above scheme, the transmission element 221 uses a screw bar 2211 set, and the slider 2212 on the screw bar 2211 moves to drive the block 21 to move. In this way, the structure is simple and the movement accuracy of the block 21 is higher.

It should be noted that the screw bar 2211 spirally drives the slider 2212 to move, and the threaded rubber of the screw bar 2211 needs to meet the self-locking condition so that the slider 2212 can be locked to the expected position.

Of course, it is understandable that the transmission element 221 is not limited to the screw rod 2211 set, but can also be any other structure that can drive the block 21 to rise and fall.

In addition, for example, as shown in FIG. 3 , the screw lever assembly further includes a guide rod 2213, and the slider 2212 can move along the guide rod 2213 to improve the movement stability of the block.

In addition, as shown in FIG3 , the driving element 222 includes a rotating shaft 2221 and a driving member 2222. The rotating shaft 2221 extends radially along the furnace chamber and penetrates the radial channel 13. A bearing is provided between the rotating shaft 2221 and the radial channel 13 so that the rotating shaft 2221 can rotate freely in 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 rotating shaft 2221 extending radially along the furnace chamber and passing through the radial channel 13. The third end and the fourth end are axially opposite to each other, the third end is placed in the installation cavity 12, the fourth end extends to the outer side of the outer peripheral wall of the furnace body 10, and the fourth end is connected to the driving member 2222; the transmission element 221 also includes: a tapered gear transmission group, the tapered gear transmission group connects the second end of the lead screw 2211 and the third end of the rotating shaft 2221, and is used for converting the rotational motion of the rotating shaft 2221 around its own axis into the rotational motion of the lead screw 2211 around its own axis.

In the above scheme, the driving member 2222 can drive the rotating shaft 2221 to rotate. The rotating shaft 2221 is axially arranged to extend along the furnace chamber radial direction, and the screw 2211 axially extends along the furnace chamber axial direction. Therefore, the transmission element 221 also adopts a tapered gear transmission group that can transmit vertical rotational motion to realize the radial rotation of the rotating shaft 2221. The axial rotational motion of the shaft 2221 is changed into the axial rotational motion of the screw lever 2211, and then the rotational motion of the screw lever 2211 is changed into the axial linear motion of the block 21. The tapered gear transmission group can also bear a part of the axial force at the same time. The moving speed of the block 21 can be controlled by changing the transmission ratio of the tapered gear transmission group.

Exemplarily, the driving member 2222 may be optionally equipped with a hand wheel to realize manual operation; the driving member 2222 may also be equipped with a driving motor to realize automatic operation.

In addition, as an exemplary embodiment, as shown in FIG3 , the bevel gear transmission group includes: A first bevel gear 223, the first bevel gear 223 is coaxially connected to the second end of the screw 2211; A second bevel gear 224, the second bevel gear 224 is coaxially connected to the third end of the rotating shaft 2221; Wherein, the bevel gears of the first bevel gear 223 and the second bevel gear 224 are engaged with each other.

For example, the outer diameter of the gear of the first bevel gear 223 is smaller than or equal to the outer diameter of the gear of the second bevel gear 224. With such a solution, the larger torque of the driving member 2222 can be converted into the smaller torque of the screw 2211, thereby achieving the purpose of more accurately adjusting the height of the block 21.

In addition, illustratively, the installation chamber 12 includes a first chamber 121 extending along the axial direction of the furnace chamber and a second chamber 122 separated from the first chamber 121, wherein the first chamber 121 is in communication with the chute 11, the screw 2211 assembly is installed in the chute 11, the second end of the screw 2211 extends from the first chamber 121 to the second chamber 122, the third end of the shaft 2221 extends from the outside of the furnace chamber to the second chamber 122, and the bevel gear transmission assembly is installed in the second chamber 122. By adopting the above solution, the second chamber 122 can provide a relatively clean space for the bevel gear transmission assembly to avoid contamination by impurities such as particles and improve its service life.

In addition, the embodiment of the present invention also provides a secondary charging method for a single crystal furnace, which is applied to the single crystal furnace in the embodiment of the present invention, and the method includes the following steps: In the process of secondary charging into the single crystal furnace through the charging tube, the charging tube is positioned and limited by the baffle 21, and the baffle 21 is moved along the axial direction of the furnace chamber according to a predetermined rule to adjust the relative distance between the charging tube and the crucible in the furnace chamber in the axial direction of the furnace chamber.

The above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by something equivalent without departing from the spirit and scope of the present invention, it should be included in the protection scope of the patent application of the present invention.

10: furnace body 11: chute 12: mounting chamber 13: radial channel 20: block mechanism 21: block 22: lifting unit 121: first chamber 122: second chamber 221: transmission element 222: driving element 223: first bevel gear 224: second bevel gear 2211: lead screw 2212: slide block 2213: guide rod 2221: rotating shaft 2222: driving element

FIG1 shows an external view of a single crystal furnace in an embodiment of the present invention; FIG2 shows a cross-sectional view of a single crystal furnace in an embodiment of the present invention; FIG3 shows an enlarged view of the local structure of the dotted frame A in FIG1.

10: Furnace body

11: Chute

12: Installation cavity

13: Radial channel

21:Block

121: First chamber

122: Second chamber

221: Transmission components

222: Driving element

223: First bevel gear

224: Second bevel gear

2211: Spindle

2212: Slider

2213: Guide rod

2221: Rotation axis

2222:Driver

Claims (9)

A single crystal furnace comprises: a furnace body, which comprises a furnace chamber; and at least one set of baffle mechanisms, each set of the baffle mechanisms comprises a baffle and a lifting unit, the baffle being arranged on the inner peripheral wall of the furnace chamber, and the baffle being connected to the lifting unit, and being able to move along the axial direction of the furnace chamber when driven by the lifting unit; a chute extending along the axial direction of the furnace chamber is arranged on the inner peripheral wall of the furnace chamber, and a mounting cavity communicating with the chute is also arranged inside the side wall of the furnace chamber, and the side wall of the furnace chamber is provided with a mounting cavity connected to the mounting cavity. A radial channel is also provided on the mounting cavity and the outer peripheral wall of the furnace chamber in a radial direction; wherein the lifting unit includes a transmission element and a driving element, the baffle is arranged corresponding to the slide groove, the driving element is at least partially exposed to the outside of the furnace chamber and connected to the transmission element through the radial channel, the transmission element is installed in the mounting cavity and connected to the baffle through the slide groove, and the driving element drives the baffle to move axially along the furnace chamber through the transmission element. The single crystal furnace as described in claim 1, wherein the baffle mechanism has at least two groups, and the at least two groups of baffle mechanisms are distributed circumferentially along the inner circumferential wall of the furnace chamber. The single crystal furnace as described in claim 1, wherein the transmission element includes a screw bar assembly, the screw bar assembly includes: a screw bar arranged along the axial direction of the furnace chamber, the screw bar having a first end and a second end opposite to each other along its own axial direction; and a slider, the slider is connected to the screw bar and can move along the screw bar as the screw bar rotates; wherein the driving element is directly or indirectly connected to the screw bar to drive the screw bar to rotate, and the block is connected to the slider to move synchronously with the slider. The single crystal furnace as described in claim 3, wherein the driving element comprises a rotating shaft and a driving member, the rotating shaft extends along the radial direction of the furnace chamber and penetrates the radial channel, the rotating shaft has a third end and a fourth end opposite to each other along its own axis, the third end is placed in the mounting cavity, the fourth end extends to the outer side of the outer peripheral wall of the furnace body, and the fourth end is connected to the driving member; the transmission element further comprises: a tapered gear transmission group, the tapered gear transmission group connects the second end of the lead screw and the third end of the rotating shaft, and is used to convert the rotational motion of the rotating shaft around its own axis into the rotational motion of the lead screw around its own axis. The single crystal furnace as described in claim 4, wherein the driving part includes a hand wheel or a driving motor. The single crystal furnace as described in claim 4, wherein the bevel gear transmission group includes: a first bevel gear, the first bevel gear is coaxially connected to the second end of the screw; a second bevel gear, the second bevel gear is coaxially connected to the third end of the rotating shaft; wherein the bevel gears of the first bevel gear and the second bevel gear are meshed with each other. The single crystal furnace as described in claim 6, wherein the outer diameter of the gear of the first bevel gear is smaller than or equal to the outer diameter of the gear of the second bevel gear. The single crystal furnace as described in claim 4, wherein, the mounting chamber includes a first chamber extending along the axial direction of the furnace chamber and a second chamber separated from the first chamber, wherein the first chamber is connected to the chute, the screw bar assembly is mounted in the chute, the second end of the screw bar extends from the first chamber to the second chamber, the third end of the rotating shaft extends from the outside of the furnace chamber to the second chamber, and the conical gear transmission assembly is mounted in the second chamber. A secondary charging method for a single crystal furnace is applied to a single crystal furnace as described in any one of claims 1 to 8, and the method comprises the following steps: during the secondary charging process into the single crystal furnace through a charging tube, the charging tube is positioned and limited by the baffle, and the baffle is moved along the axial direction of the furnace chamber according to a predetermined rule to adjust the relative distance between the charging tube and the crucible liquid level in the furnace chamber in the axial direction of the furnace chamber.

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