CN115369478B

CN115369478B - Crystal remelting control method and equipment, crystal pulling furnace and computer storage medium

Info

Publication number: CN115369478B
Application number: CN202110552586.2A
Authority: CN
Inventors: 武高峰; 李侨; 徐战军; 赵会刚; 张伟建; 赵阳; 贺瑞环; 刘永生; 李羊飞; 周宏坤; 杨正华
Original assignee: Longi Green Energy Technology Co Ltd
Current assignee: Longi Green Energy Technology Co Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2024-03-01
Anticipated expiration: 2041-05-20
Also published as: CN115369478A

Abstract

The invention discloses a crystal remelting control method and equipment, a crystal pulling furnace and a computer storage medium, relates to the technical field of crystal bar crystal pulling, and aims to automatically control crystal bar remelting, so that the control of the crystal bar is more accurate, the remelting efficiency is improved, and the labor cost is reduced. The crystal remelting control method comprises the following steps: under the condition of broken line of the crystal, the crucible lifting device is controlled to lower the crucible from the broken line crucible position of the crystal to the return crucible position of the crystal. When the crucible is lowered to the position where the crystal returns to the crucible, the crystal pulling device is controlled to adjust the position of the crystal, so that the crystal is contacted with the liquid level of the melt. When the crystal contacts with the liquid level of the melt, the heater is controlled to carry out the remelting operation on the crystal. And under the condition that the exothermic amount of the heater is larger than or equal to the reflow endothermic amount of the crystal according to the crystal endothermic parameter and the heater exothermic parameter, determining that the crystal is converted into a melt.

Description

Crystal remelting control method and equipment, crystal pulling furnace and computer storage medium

Technical Field

The invention relates to the technical field of crystal bar pulling, in particular to a crystal reflow control method and equipment, a pulling furnace and a computer storage medium.

Background

At present, in the Czochralski method, raw materials are placed in a crucible of a crystal pulling furnace, the raw materials are heated and melted in the crystal pulling furnace, then a single crystal seed crystal is immersed into the melt, the melt grows along the seed crystal through accurate temperature control, and a crystal bar (also called as a crystal) for solar photovoltaic is finally formed through the processes of seeding, shouldering, shoulder turning, isodiametric and ending. However, during the growth of the ingot, breakage of the ingot (also known as edge breakage) tends to occur.

In the prior art, the broken wire is processed in such a way that the broken wire crystal bar is stretched into a crucible for melting for a plurality of times until all the melting back is completed. In the process of stretching the ingot into the crucible for a plurality of times, field personnel are required to judge whether the ingot in the crucible is melted or not according to experience. However, the judgment of personnel may be due to different personnel technologies and experiences, so that the time when the crystal bar stretches into the crucible is different, the crucible is poked by the crystal bar or the melting efficiency is low, and the crystal bar needs to be observed manually at any time, so that the labor intensity is increased, and the labor cost is increased.

Disclosure of Invention

The invention aims to provide a crystal remelting control method and equipment, a crystal pulling furnace and a computer storage medium, which can automatically control crystal rod remelting, so that the control of the crystal rod is more accurate, the remelting efficiency is improved, and the labor cost is reduced.

In a first aspect, the invention provides a crystal reflow control method applied to a crystal pulling furnace. The crystal pulling furnace comprises a crucible lifting device, a crystal lifting device and a heater. The crucible lifting device is used for adjusting the crucible position of the crucible, and the crucible is used for containing melt.

The crystal remelting control method comprises the following steps: under the condition of broken line of the crystal, the crucible lifting device is controlled to lower the crucible from the broken line crucible position of the crystal to the return crucible position of the crystal. When the crucible is lowered to the position where the crystal returns to the crucible, the crystal pulling device is controlled to adjust the position of the crystal, so that the crystal is contacted with the liquid level of the melt. When the crystal contacts with the liquid level of the melt, the heater is controlled to carry out the remelting operation on the crystal. And under the condition that the exothermic amount of the heater is larger than or equal to the reflow endothermic amount of the crystal according to the crystal endothermic parameter and the heater exothermic parameter, determining that the crystal is converted into a melt.

Under the condition of adopting the technical scheme, in the process of controlling the heater to carry out the reflow operation on the crystal, the invention determines that the crystal is converted into the melt under the condition that the heat release quantity of the heater is larger than or equal to the reflow heat release quantity of the crystal according to the heat release parameter of the crystal and the heat release parameter of the heater. Compared with the prior art, the invention can improve the accuracy of judging whether the crystal in the crucible is melted on the basis of reducing labor cost by judging whether the crystal in the crucible is melted or not according to experience by field personnel, thereby not only avoiding the crucible from being poked by the crystal, but also improving the remelting efficiency.

And before remelting, the crucible is lowered from the broken line crucible position to the crystal remelting crucible position by controlling the crucible lifting device, and the crystal is contacted with the liquid level of the melt by controlling the crystal lifting device, so that the situation that the crystal is relatively close to the liquid level Huang Zijian when the broken line crucible position of the crystal is directly contacted with the liquid level of the melt, the crystal stretches into the liquid level and the melt can be immersed into a heat shield is avoided.

In one possible implementation, the controlling the crucible lifting device to lower the crucible from the crystal breakage crucible position to the crystal return crucible position includes:

the crucible lifting device is controlled to descend the crucible from the broken line crucible position to the crucible preheating position, and the heater is controlled to preheat the crucible which descends to the crucible preheating position.

The crucible lifting device is controlled to lower the crucible from the crucible preheating crucible position to the crystal return crucible position.

Under the condition of adopting the technical scheme, before the remelting operation, the crucible lifting device is controlled to descend the crucible from the broken line crucible position of the crystal to the crucible preheating position, and the heater is controlled to fully preheat the crucible which descends to the crucible preheating position. After the preheating is finished, controlling the crucible lifting device to descend the crucible from the crucible preheating crucible position to the crystal return crucible position for remelting.

In one possible implementation, the controlling the crucible lifting device to lower the crucible from the crystal breakage crucible position to the crucible preheating crucible position includes:

the crucible lifting device is controlled to descend the crucible from the broken line crucible position of the crystal. And acquiring an actual crucible position of the crucible, and controlling the heater to preheat the crucible under the condition that the actual crucible position of the crucible is the crucible preheating position.

In one possible implementation, the controlling the crucible lifting device to lower the crucible from the crucible preheating crucible position to the crystal return crucible position includes:

the crucible lifting device is controlled to start to descend the crucible from the crucible preheating position. Acquiring an actual crucible position of the crucible, and determining that the actual crucible position of the crucible is equal to the crystal crucible return position of the crucible under the condition that the actual crucible position of the crucible is lower than or equal to the initial crucible return position of the crystal.

In one possible implementation, the initial return crucible position is determined by the seeding crucible position height and the first crucible position correction parameter. Wherein initial crucible return = seeding crucible level height-first crucible level correction parameter.

Under the condition of adopting the technical scheme, the initial crucible return position is determined by the seeding crucible position height and the first crucible position correction parameter. Since the seeding crucible position of the crystal is known in height, the initial crucible position return can be controlled by setting the first crucible position correction parameter.

In one possible implementation, the first crucible position correction parameter is 5mm to 40mm.

In one possible implementation, the crucible preheating crucible position is determined by a crystal breakage crucible position and a second crucible position correction parameter. Wherein crucible pre-heat crucible position = crystal break crucible position height-second crucible position correction parameter.

Under the condition of adopting the technical scheme, the crucible preheating crucible position is determined by the height of the broken line crucible position of the crystal and the correction parameter of the second crucible position under the condition of adopting the technical scheme. The crucible position of the broken line of the crystal is known in height, and the crucible can be controlled to preheat the crucible position by setting the correction parameter of the second crucible position.

In one possible implementation, the second crucible position correction parameter is 20mm to 60mm.

In one possible implementation manner, before controlling the heater to perform the reflow operation on the crystal in the case of the broken crystal line, the crystal reflow control method further includes:

the heater is controlled to adjust the power from the wire break heating power to the crystal reflow power.

In one possible implementation, the break heating power and the crystal reflow power change linearly.

Under the condition of adopting the technical scheme, the broken wire heating power and the crystal reflow power are in linear change, so that the temperature of the melt in the crucible is increased linearly, and the phenomenon that the quality of crystal pulling is influenced due to overlarge temperature change of the melt in the crucible is avoided.

In one possible implementation, the time used for the control heater to adjust the power from the off-line heating power to the crystal reflow power is 5s to 600s.

Through the research of the inventor, the time for controlling the heater to adjust the power from the wire-break heating power to the crystal remelting power is too short, so that the temperature in the crucible can be changed drastically, the quality of the melt is influenced, and the crystal pulling quality is influenced; controlling the heater to adjust the power from the off-line heating power to the crystal remelting power for too long can affect the remelting power efficiency. And the time for adjusting the power from the wire-breaking heating power to the crystal remelting power by controlling the heater is 5 s-600 s, so that the remelting efficiency is improved as much as possible under the condition of ensuring the crystal pulling quality.

In one possible implementation, the crystal has a first crystal section near the liquid surface and a second crystal section far from the liquid surface, and the length of the second crystal section is smaller than that of the first crystal section. The crystal remelting power of the heater in the first crystal section is larger than that of the heater in the second crystal section.

Under the condition of adopting the technical scheme, the crystal is provided with a first crystal section close to the liquid level and a second crystal section far away from the liquid level. Based on the above, during reflow, the first crystal section is reflowed first, and then the second crystal section is reflowed. Because the back melting power of the heater is larger than the seeding power, and the crystal back melting power of the heater in the first crystal section is larger than the crystal back melting power of the heater in the second crystal section, after the crystal is completely back melted, the power of the heater is more close to the seeding power, the time for adjusting the power of the heater to the seeding power can be reduced, the working efficiency is improved, and the influence on the crystal pulling quality due to overlarge power change of the heater is avoided.

In one possible implementation, the crystal reflow power of the heater at the first crystal segment is determined by the seeding power and the first power correction parameter. Wherein, the crystal reflow power of the heater at the first crystal section=seeding power+the first correction power parameter. The first correction power parameter is 10 kw-25 kw.

Under the condition of adopting the technical scheme, the crystal remelting power of the heater in the first crystal section is determined by the seeding power and the first power correction parameter. Since the seeding power is known, the crystal remelting power of the heater at the first crystal section can be controlled by setting the first power correction parameter. And after the back melting is finished, the crystal back melting power of the heater in the first crystal section is calculated through the seeding power, so that the power of the heater can be conveniently adjusted to the seeding power in the follow-up process.

The inventor researches find that the crystal remelting power is too high, and after the remelting is finished, the power of the heater is not easy to drop to the seeding power, so that the working efficiency is low; and the crystal remelting power is too small, the remelting time is too long, and the working efficiency is low. And the first correction power parameter is 10 kw-25 kw, so that the crystal remelting power of the heater in the first crystal section is moderate, and the working efficiency is improved.

In one possible implementation, the crystal reflow power of the heater at the second crystal section is determined by the seeding power and the second power correction parameter. Wherein, the crystal reflow power of the heater in the second crystal section=seeding power+the second correction power parameter, and the second correction power parameter is 0 kw-10 kw.

Under the condition of adopting the technical scheme, the crystal remelting power of the heater in the second crystal section is determined by the seeding power and the second power correction parameter. Since the seeding power is known, the crystal reflow power of the heater at the second crystal section can be controlled by setting the second power correction parameter.

The inventor researches find that the crystal remelting power is too high, and after the remelting is finished, the power of the heater is not easy to drop to the seeding power, so that the working efficiency is low; and the crystal remelting power is too small, the remelting time is too long, and the working efficiency is low. And the second correction power parameter is 0 kw-10 kw, so that the crystal remelting power of the heater in the second crystal section is moderate, thereby improving the working efficiency.

In one possible implementation manner, the controlling the heater to perform a reflow operation on the crystal includes:

and controlling the crystal to perform the sectional remelting operation according to the sectional remelting parameters.

Determining that the crystal is converted into a melt when the exothermic amount of the heater is greater than or equal to the reflow endothermic amount of the crystal according to the crystal endothermic parameter and the heater exothermic parameter, comprising:

and determining the sectional reflow heat absorption quantity of the crystal according to the sectional reflow parameters. And determining the theoretical time length of the crystal section remelting according to the heat absorption quantity of the crystal section remelting and the heat release parameter of the heater, and determining that the crystal section remelting is finished under the condition that the time length of the crystal section remelting is greater than or equal to the theoretical time length of the crystal section remelting.

Under the condition of adopting the technical scheme, the crystal is controlled to carry out the sectional remelting operation according to the sectional remelting parameters, and the crystal is stretched into the crucible for remelting in sections.

And determining the sectional reflow heat absorption quantity of the crystal according to the sectional reflow parameters. And determining the theoretical time length of the crystal section remelting according to the heat absorption quantity of the crystal section remelting and the heat release parameter of the heater, and determining that the crystal section remelting is finished under the condition that the time length of the crystal section remelting is greater than or equal to the theoretical time length of the crystal section remelting. Therefore, whether the segmented remelting of the crystal is finished can be determined through the remelting time, the accuracy of judging whether the crystal in the crucible is melted can be improved on the basis of reducing labor cost, the crucible is prevented from being poked by the crystal, and the remelting efficiency is improved.

In one possible implementation, the above-mentioned segment remelting parameter is a segment remelting length, where a segment remelting length is a length of a crystal that extends into a melt at a time. When the crystal has a first crystal section close to the liquid surface and a second crystal section far away from the liquid surface, the diameter of the first crystal section is larger than that of the second crystal section. The segmented reflow length of the second crystal section is 1-3 times of that of the first crystal section.

Under the condition of adopting the technical scheme, as the diameter of the first crystal section is larger than that of the second crystal section, the heat release quantity of the heater corresponding to the first crystal section is larger than that of the heater corresponding to the second crystal section within the same length. Based on the method, the segmented reflow length of the second crystal section is 1-3 times of that of the first crystal section, and the second crystal section with longer length can be melted in the same time, so that the reflow efficiency is improved.

In one possible implementation, the segmented reflow length is 20mm to 40mm.

Under the condition of adopting the technical scheme, the inventor researches that the segmented remelting length is too long, so that the situation of poking the crucible is easy to occur; the segmented reflow length is too short, the number of the multi-segment reflow is too large, and the reflow efficiency is low. The segmented remelting length is 20-40 mm, so that the safety of remelting is ensured, and the remelting efficiency is improved.

In one possible implementation, the crystal endothermic parameter includes a crystal melting parameter and a crystal crystallization latent heat parameter. Wherein,

the crystal melting parameters include the mass of the crystal, the specific heat of the crystal, and the amount of temperature change.

The crystal crystallization latent heat parameter includes the heat of fusion of the crystal and the number of moles of the crystal.

The heater heat release parameters include the power of the heater and the heating time.

In one possible implementation, the crystal rotation of the crystal pulling furnace is 3-7 rpm during the reflow operation.

Under the condition of adopting the technical scheme, the inventor researches that the crystal rotation speed of the crystal pulling furnace is too high and the heat loss is larger in the process of remelting operation; the crystal rotation speed of the crystal pulling furnace is too slow, and the crystals are heated unevenly. The crystal of the crystal pulling furnace is changed into 3-7 revolutions per minute, so that heat damage can be reduced, and the crystal can be heated uniformly.

In one possible implementation, the crucible of the crystal pulling furnace is turned between 0.5 rpm and 4 rpm during the reflow operation.

Under the condition of adopting the technical proposal, the inventor researches that the crucible of the crystal pulling furnace rotates too fast and the heat loss is larger in the process of the reflow operation; the crucible of the crystal pulling furnace rotates at too slow a speed, and the crystals are heated unevenly. The crucible of the crystal pulling furnace is changed into 0.5-4 revolutions/min, so that heat damage can be reduced, and crystals can be heated uniformly.

In a second aspect, the present invention also discloses a crystal pulling control apparatus comprising: the processor is used for running a computer program or instructions to realize the crystal reflow control method.

In a third aspect, the invention also discloses a crystal pulling furnace, which comprises a crucible lifting device, a crystal lifting device, a heater and crystal pulling control equipment. The crystal pulling control device is in communication connection with the crucible lifting device, the crystal lifting device and the heater.

In a fourth aspect, the present invention also discloses a computer storage medium, in which instructions are stored, and when the instructions are executed, the crystal reflow control method is implemented.

Advantageous effects of the second aspect, the third aspect, the fourth aspect, and various implementations thereof in the present invention are the same as those of the first aspect or any possible implementation of the first aspect, and are not described here again.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:

FIG. 1 shows a flow chart of steps of a crystal reflow control method provided by an embodiment of the present invention;

FIG. 2 shows a schematic crystal diagram provided by an embodiment of the present invention;

FIG. 3 shows a schematic hardware configuration of a crystal pulling control device according to an embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is only exemplary and is not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the concepts of the present disclosure.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. The meaning of "a number" is one or more than one unless specifically defined otherwise.

At present, in the Czochralski method, raw materials are placed in a crucible of a crystal pulling furnace, the raw materials are heated and melted in the crystal pulling furnace, then a single crystal seed crystal is immersed into the molten liquid, the molten liquid grows along the seed crystal through accurate temperature control, and finally a crystal bar for solar photovoltaic is formed through the processes of seeding, shouldering, shoulder rotating, isodiametric and ending. However, during the growth of the ingot, breakage of the ingot (also known as edge breakage) tends to occur.

In the prior art, the broken wire is processed in such a way that the broken wire crystal bar is stretched into a crucible for melting for a plurality of times until all the melting back is completed. In the process of stretching the ingot into the crucible for a plurality of times, field personnel are required to judge whether the ingot in the crucible is melted or not according to experience. However, the judgment of the personnel may be different due to different technologies and experiences of the personnel, so that the time when the ingot stretches into the crucible is different. The interval that the crystal bar stretches into the crucible is too short, the crystal bar in the crucible is not melted yet, and when the crystal bar stretches into the crystal bar continuously, the crystal bar is poked out of the crucible; the interval that the crystal bar stretches into the crucible is overlength, can lead to the work efficiency of back melting low, needs the manual work to observe at any time moreover, increases intensity of labour, increases the cost of labor.

Based on the above, the embodiment of the invention discloses a crystal pulling furnace, which is equipment for melting polycrystalline materials such as polycrystalline silicon and the like in an inert gas (nitrogen and helium are mainly) environment and growing dislocation-free single crystal silicon rods by using a Czochralski method. In an embodiment of the invention, the crystal pulling furnace comprises a crucible lifting device, a crystal lifting device and a heater. The crucible lifting device is used for adjusting the crucible position of the crucible. The crucible is used for containing melt. The crystal pulling device is used for pulling the crystal and adjusting the position of the crystal. The heater is used for heating the melt in the crucible.

Further, the crystal pulling furnace further comprises a crystal position detecting device, a crystal diameter detecting device, a crystal length detecting device and a crucible position detecting device. The crystal position detecting device is used for detecting the position of the crystal in the crystal pulling furnace. The crystal length detection device is used for detecting the length of the crystal. The crystal diameter detection device is used for detecting the diameter of each place of the crystal. The crucible position detection device is used for detecting the position of the crucible in the crystal pulling furnace.

Furthermore, the crystal pulling furnace further comprises a crystal lifting abnormality detection module, a crucible lifting abnormality detection module and a crystal position abnormality detection module after melting back is completed. The crystal lifting abnormality detection module is used for detecting the abnormal lifting of the crystal. The crucible lifting abnormality detection module is used for detecting crucible lifting abnormality. The crystal position abnormality detection module is used for detecting the abnormal crystal position after the melting back is finished.

According to the crystal lifting abnormal detection module, the crystal lifting speed is set, the crystal position change in corresponding time is calculated, the crystal position change is compared with the corresponding crystal encoder position change quantity, the reliability of the crystal encoder position is judged, the external faults of the encoder and the coupler are eliminated, and the abnormal occurrence of the reflow function is prevented due to the abnormal external hardware.

According to the crucible lifting abnormality detection module, the crucible lifting speed is set, the crucible position change in corresponding time is calculated, the crucible position change is compared with the corresponding crucible encoder position change quantity, the reliability of the position of the crucible encoder is judged, the external faults of the encoder and the coupling are eliminated, and the abnormality of external hardware is prevented, so that the abnormal reflow function is caused.

And the crystal position abnormality detection module after the melting back is finished compares the obtained crystal position after the melting back with the lower limit of the crystal melting back position. As safety judgment, the lower limit range of the position of the remelting crystal is 100 mm-200 mm.

The embodiment of the invention also discloses a crystal remelting control method which is applied to the crystal pulling furnace. Referring to fig. 1, the crystal reflow control method includes the steps of:

s101: under the condition of broken line of the crystal, the crucible lifting device is controlled to lower the crucible from the broken line crucible position of the crystal to the return crucible position of the crystal.

In practical application, under the condition of broken lines of the crystal, the diameter of each part of the crystal, the length of the crystal, the position of the crucible and the position of the crystal are obtained.

In the embodiment of the invention, when the condition of the broken line of the crystal is found or the signal of the broken line of the crystal is obtained, the crucible lifting device is controlled to descend the crucible from the crucible position of the broken line of the crystal to the crucible position of the crystal return. The crucible is lowered from the broken line crucible position to the return crucible position, so that the situation that when the broken line crucible position of the crystal is directly contacted with the liquid level of the melt, the distance between the crystal and the liquid level Huang Zijian is relatively short, the crystal stretches into the liquid level, and the melt can be immersed into a heat shield can be avoided.

In one example, controlling the crucible lifting device to lower the crucible from the crystal breakage crucible position to the crystal return crucible position may include:

the crucible lifting device is controlled to descend the crucible from the broken line crucible position to the crucible preheating position, and the heater is controlled to preheat the crucible which descends to the crucible preheating position. Specifically, the crucible lifting device is controlled to lower the crucible from the broken line crucible position of the crystal. And acquiring an actual crucible position of the crucible, and controlling the heater to preheat the crucible under the condition that the actual crucible position of the crucible is the crucible preheating position. In the process of lowering the crucible to the crystal remelting, the crucible position is preheated by the crucible, so that the molten liquid in the crucible can be preheated better.

After the preheating is finished, the crucible lifting device is controlled to descend the crucible from the crucible preheating crucible position to the crystal return crucible position. Specifically, the crucible lifting device is controlled to lower the crucible from the crucible pre-heating crucible position. Acquiring an actual crucible position of the crucible, and determining that the actual crucible position of the crucible is equal to the crystal crucible return position of the crucible under the condition that the actual crucible position of the crucible is lower than or equal to the initial crucible return position of the crystal.

In one example, the initial return crucible level described above can be determined from the seeding crucible level height and the first crucible level correction parameter. Initial crucible return = seeding crucible level height-first crucible level correction parameter. The initial crucible return position is determined by the seeding crucible position height and the first crucible position correction parameter. Before the crystal is remelted, the crystal is subjected to a seeding stage, so that the height of the seeding crucible position of the crystal is known, and the initial reflow crucible position can be controlled by setting the first crucible position correction parameter. And the seeding crucible position is the highest safe position, and the crucible can be lowered to the heating core area of the heater according to different thermal fields by lowering a certain first crucible position correction parameter through the seeding crucible position. For example, the first crucible position correction parameter may be 5mm to 40mm.

In one example, the crucible preheating crucible position may be determined from the crystal breakage crucible position and the second crucible position correction parameter. Crucible pre-heat crucible position = crystal break crucible position height-second crucible position correction parameter. The crucible preheating crucible position is determined by the height of the broken line crucible position of the crystal and the correction parameter of the second crucible position. The crucible level height of the broken line of crystals, i.e. the crucible level height when the broken line of crystals is found, can also be understood as the crucible level height when the crystals are ready to be remelted. The crucible position of the broken line of the crystal is known in height, and the crucible can be controlled to preheat the crucible position by setting the correction parameter of the second crucible position.

The second crucible position correction parameter may be 20mm to 60mm. Through researches of the inventor, the correction parameter of the second crucible position is overlarge, the crucible position is lower, the upper wall of the crucible is close to the heater, and the collapse is easy to cause; the correction parameters of the second crucible position are too small, the crucible position is close to the heat exchanger, and the melt is heated to easily cause the blowing. And the correction parameter of the second crucible position is 20-60 mm, so that the distance between the crucible and the heater and the heat exchanger is moderate, and the remelting process is more stable.

In practical application, the crucible preheating position is calculated according to the height of the broken line crucible position of the crystal and the second crucible position correction parameter, wherein the second crucible position correction parameter is the first lowering distance of the crucible, and can be understood as the lowering distance of the crucible from the broken line crucible position of the crystal to the crucible preheating position.

And then calculating an initial crucible return position according to the height of the seeding crucible and the first crucible position correction parameter. And calculating the distance from the crucible preheating crucible position to the crystal return crucible position when the crucible descends from the crucible preheating crucible position through the initial return crucible position and the crucible preheating crucible position.

When the height of the crucible preheating crucible position is higher than the height of the initial crucible returning position, the difference between the height of the crucible preheating crucible position and the height of the initial crucible returning position is the distance from the crucible preheating crucible position to the crystal crucible returning position.

When the height of the crucible preheating crucible position is lower than or equal to the height of the initial crucible returning position, the crucible preheating crucible position is the initial crucible returning position, and the crucible positioned at the crucible preheating crucible position does not need to descend.

Based on the above, before the remelting operation, the crucible lifting device is controlled to lower the crucible from the broken line crucible position to the crucible preheating position, and the heater is controlled to fully preheat the crucible which is lowered to the crucible preheating position. After the preheating is finished, controlling the crucible lifting device to descend the crucible from the crucible preheating crucible position to the crystal return crucible position for remelting.

S102, when the crucible is lowered to the position where the crystal returns to the crucible, controlling the crystal pulling device to adjust the position of the crystal so that the crystal contacts with the liquid level of the melt.

Specifically, the crystal pulling device is controlled to drive the crystal to descend so that the crystal contacts with the liquid level of the melt. The distance that the crystal lifting device drives the crystal to descend is: the difference between the height of the crystal break line crucible level and the height of the crystal return crucible level.

Before controlling the heater to carry out the remelting operation on the crystal, the crystal remelting control method further comprises the following steps: the heater is controlled to adjust the power from the wire break heating power to the crystal reflow power.

In one example, the wire break heating power and the crystal reflow power may change linearly.

The broken wire heating power and the crystal remelting power are linearly changed, so that the temperature of the melt in the crucible is linearly increased, and the phenomenon that the quality of crystal pulling is influenced due to overlarge temperature change of the melt in the crucible is avoided.

In one example, the time used by the control heater to adjust power from off-line heating power to crystal reflow power may be between 5s and 600s.

Referring to fig. 2, the crystal has a first section 10 near the liquid surface and a second section 20 far from the liquid surface. The second wafer section 20 has a length less than the length of the first wafer section 10. Wherein the crystal reflow power of the heater at the first die section 10 is greater than the crystal reflow power of the heater at the second die section 20. In an embodiment of the present invention, the first crystal section 10 may be an equal diameter section, and the second crystal section 20 may be a shoulder section.

Specifically, referring to fig. 2, during reflow, the heater is controlled to adjust the power from the off-line heating power to the crystal reflow power of the heater in the first crystal segment 10. The first crystal section 10 is melted back first, and when the first crystal section 10 is melted back. The heater is controlled to adjust the power from the crystal reflow power of the heater in the first crystal section 10 to the crystal reflow power of the heater in the second crystal section 20, and the second crystal section 20 is continuously reflow. After the second crystal section 20 is melted back, the heater is controlled to adjust the power to seeding power, and the seeding is started again.

Based thereon, referring to fig. 2, the crystal has a first crystal section 10 near the liquid surface and a second crystal section 20 far from the liquid surface. In the reflow process, the first wafer 10 is reflowed, and then the second wafer 20 is reflowed. Because the crystal rod needs to be remelted into a melt during remelting, the remelting power of the heater is larger than the seeding power, and the crystal remelting power of the heater in the first crystal section 10 is larger than the crystal remelting power of the heater in the second crystal section 20, so that after the crystal is completely remelted, the power of the heater is more similar to the seeding power, the time for adjusting the power of the heater into the seeding power can be reduced, the working efficiency is improved, and the influence on the crystal pulling quality due to overlarge power change of the heater is avoided.

The crystal reflow power of the heater at the first crystal segment can be determined by the seeding power and the first power correction parameter. Wherein, the crystal reflow power of the heater at the first crystal section=seeding power+the first correction power parameter.

The crystal reflow power of the heater at the first die is determined by the seeding power and the first power correction parameter. Since the seeding stage has already been passed when the crystal is reflowed, the seeding power is known. By setting the first power correction parameter, the crystal reflow power of the heater at the first crystal section can be controlled. And after the back melting is finished, the crystal back melting power of the heater in the first crystal section is calculated through the seeding power, so that the power of the heater can be conveniently adjusted to the seeding power in the follow-up process.

In one example, the first correction power parameter may be 10kw to 25kw.

The crystal reflow power of the heater at the second crystal section may be determined by the seeding power and the second power correction parameter. Wherein, the crystal reflow power of the heater at the second crystal section = seeding power + second correction power parameter.

The crystal reflow power of the heater at the second crystal section is determined by the seeding power and the second power correction parameter. The seeding power is known, and by setting the second power correction parameter, the crystal reflow power of the heater in the second crystal section can be controlled. And after the back melting is finished, the seeding is needed again, so that the back melting power of the heater in the crystal of the second crystal section is calculated through the seeding power, and the power of the heater is conveniently adjusted to the seeding power in the follow-up process.

In one example, the second correction power parameter may be 0kw to 10kw.

S103, controlling the heater to carry out a remelting operation on the crystal when the crystal is contacted with the melt liquid level.

The crystal pulling device drives the crystal to descend so that the crystal stretches into the melt, and the crystal is melted in the melt.

In the process of the remelting operation, the crystal rotation of the crystal pulling furnace can be 3-7 revolutions/min. Through the research of the inventor, the crystal rotation speed of the crystal pulling furnace is too high in the process of the reflow operation, and the heat loss is larger; the crystal rotation speed of the crystal pulling furnace is too slow, and the crystals are heated unevenly. The crystal of the crystal pulling furnace is changed into 3-7 revolutions per minute, so that heat damage can be reduced, and the crystal can be heated uniformly.

In the process of the remelting operation, the crucible rotation of the crystal pulling furnace can be 0.5-4 revolutions/min. Through the research of the inventor, during the remelting operation, the crucible of the crystal pulling furnace rotates too fast, and the heat loss is larger; the crucible of the crystal pulling furnace rotates at too slow a speed, and the crystals are heated unevenly. The crucible of the crystal pulling furnace is changed into 0.5-4 revolutions/min, so that heat damage can be reduced, and crystals can be heated uniformly.

S104, determining that the crystal is converted into a melt under the condition that the exothermic amount of the heater is larger than or equal to the reflow endothermic amount of the crystal according to the crystal endothermic parameter and the heater exothermic parameter.

The crystal endothermic parameter includes a crystal melting parameter and a crystal crystallization latent heat parameter. Crystal endotherm parameter = crystal fusion parameter + crystal latent heat of crystallization parameter.

The above crystal melting parameters include the mass of the crystal, the specific heat of the crystal, and the amount of temperature change. Crystal melting parameter = specific heat of crystal x mass of crystal x temperature change. The specific heat of the crystal is known when calculating the crystal melting parameter. The volume of the crystal can be calculated by the length of the crystal and the diameter of the crystal, and then the mass of the crystal can be calculated by the density of the crystal. The temperature change refers to the difference between the temperature of the melt level and the temperature of the crystal melting point. In practical applications, the amount of temperature change is known. From this, the crystal melting parameter can be calculated.

The above-mentioned crystal crystallization latent heat parameter includes the heat of fusion of the crystal and the number of moles of the crystal. Crystal crystallization latent heat parameter = heat of fusion of crystal x moles of crystal. The heat of fusion of the crystals and the number of moles of the crystals are known, whereby the latent heat of crystallization parameter of the crystals can be calculated.

The crystal heat absorption parameter, namely the back melting heat of the crystal, can be calculated through the crystal melting parameter and the crystal crystallization latent heat parameter.

The heat release parameter of the heater is the heat release quantity of the heater. The heater heat release parameters include the power of the heater and the heating time. Heater heat release parameter = power of heater x heating time. When the power of the heater is known and the heat absorption quantity of the crystal is obtained, the theoretical crystal remelting duration can be calculated. When the crystal is remelted, when the heating time of the heater is longer than or equal to the theoretical period of crystal remelting, the crystal can be accurately known to be converted into melt.

The heat release from the heater cannot be completely converted into the heat back-melt absorption of the crystal due to heat loss. In practical application, when the back melting heat absorption quantity of the crystal is larger than or equal to the heat release quantity of the k multiplied by the heater, the crystal is determined to be converted into a melt. k is larger than or equal to 1, and k can be set according to the working environment of an actual crystal pulling furnace, and is not limited.

Based on the above, in the process of controlling the heater to carry out the remelting operation on the crystal, under the condition that the exothermic capacity of the heater is larger than or equal to the remelting heat capacity of the crystal according to the endothermic parameter of the crystal and the exothermic parameter of the heater, the invention determines that the crystal is converted into a melt. Compared with the prior art, the invention can improve the accuracy of judging whether the crystal in the crucible is melted on the basis of reducing labor cost by judging whether the crystal in the crucible is melted or not according to experience by field personnel, thereby not only avoiding the crucible from being poked by the crystal, but also improving the remelting efficiency.

In practical applications, the height of the crucible is generally smaller than the length of the crystal, the crucible cannot accommodate the entire crystal at one time, and the crystal needs to be melted back in sections. Therefore, controlling the heater to perform the reflow operation on the crystal includes controlling the crystal to perform the piecewise reflow operation according to the piecewise reflow parameters.

The above-mentioned segmentation melt-back parameter is the segmentation melt-back length, in practical application, according to the whole length of crystal when breaking the line, according to predetermineeing the segmentation melt-back length, divide into the multistage with the crystal. The segmented remelting length is the length of each time the crystal stretches into the melt, namely the length of each time the crystal is remelted.

The segment remelting length can be 20 mm-40 mm. The inventor researches that the segmented remelting length is too long, so that the condition of poking the crucible is easy to occur; the segmented reflow length is too short, the number of the multi-segment reflow is too large, and the reflow efficiency is low. The segmented remelting length is 20-40 mm, so that the safety of remelting is ensured, and the remelting efficiency is improved.

Referring to fig. 2, when the crystal has the above-described first crystal section 10 near the liquid surface and the second crystal section 20 far from the liquid surface, the diameter of the first crystal section 10 is larger than that of the second crystal section 20. Wherein the segmented reflow length of the second crystal segment 20 is 1-3 times of the segmented reflow length of the first crystal segment 10. In one example, the first wafer section 10 may be an isodiametric section and the second wafer section 20 may be a shouldered section.

Referring to fig. 2, since the diameter of the first crystal section 10 is larger than that of the second crystal section 20, the heat release amount of the heater corresponding to the first crystal section 10 is larger than that of the heater corresponding to the second crystal section 20 within the same length. Based on this, the segmented reflow length of the second crystal section 20 is 1 to 3 times that of the first crystal section 10, and the second crystal section 20 having a longer length can be melted in the same time, thereby improving the reflow efficiency.

and determining the sectional reflow heat absorption quantity of the crystal according to the sectional reflow parameters.

Specifically, the volume of each section of crystal is calculated according to the length and the diameter of each section of crystal, and the mass of each section of crystal can be calculated by combining the density of the crystals. The heat absorption quantity of the crystal segment of each section of crystal can be calculated according to the mass of each section of crystal.

And determining the theoretical time length of the crystal segment remelting according to the heat absorption quantity of the crystal segment remelting and the heat release parameter of the heater.

Specifically, according to the power of the heater and the heat absorption quantity of the crystal section melting back corresponding to each section of crystal, the corresponding time length of the crystal section melting back of each section of crystal can be calculated.

And under the condition that the crystal segment remelting time length is larger than or equal to the crystal segment remelting theoretical time length, determining that the crystal segment remelting is finished.

Specifically, when each section of crystal is melted back, the completion of the melting back of each section of crystal can be quickly determined when the heating time length of each section of crystal is determined to be greater than or equal to the crystal subsection melting back theoretical time length corresponding to each section of crystal.

Based on the above, the stage reflow heat absorption amount of the crystal is determined according to the stage reflow parameters. And determining the theoretical time length of the crystal section remelting according to the heat absorption quantity of the crystal section remelting and the heat release parameter of the heater, and determining that the crystal section remelting is finished under the condition that the time length of the crystal section remelting is greater than or equal to the theoretical time length of the crystal section remelting. Therefore, whether the segmented remelting of the crystal is finished can be determined through the remelting time, the accuracy of judging whether the crystal in the crucible is melted can be improved on the basis of reducing labor cost, the crucible is prevented from being poked by the crystal, and the remelting efficiency is improved.

Referring to FIG. 3, the actions performed by the crystal pulling control device described above may be stored as computer instructions in the crystal pulling control device's memory 220, the computer instructions stored in the memory 220 being executed by the processor 210.

The crystal pulling control apparatus 200 includes: processor 210 and communication interface 230, communication interface 230 and processor coupling 210, processor 210 being configured to execute computer programs or instructions. The crystal pulling control apparatus 200 may be in communication with the crucible lifting device, the crystal pulling device, and the heater via the communication interface 230.

Referring to fig. 3, the processor 210 may be a general purpose central processing unit (central processing unit, CPU), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present invention. The communication interface 230 may be one or more. The communication interface 230 may use any transceiver-like device for communicating with other devices or communication networks.

Referring to FIG. 3, the crystal pulling control apparatus 200 described above may also include a communication line 240. Communication line 240 may include a pathway to transfer information between the aforementioned components.

Optionally, referring to FIG. 3, the crystal pulling control apparatus 200 may also include a memory 220. Memory 220 is used to store computer instructions for performing the execution of aspects of the present invention and is controlled by processor 210. Processor 210 is operative to execute computer instructions stored in memory 220.

As shown in fig. 3, the memory 220 may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (random access memory, RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (electrically erasable programmable read-only memory, EEPROM), a compact disc (compact disc read-only memory) or other optical disk storage, optical disk storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 220 may be stand alone and be coupled to the processor 210 via a communication line 240. Memory 220 may also be integrated with processor 210.

Alternatively, the computer instructions in the embodiments of the present invention may be referred to as application program codes, which are not limited in particular.

In a particular implementation, referring to FIG. 3, as one embodiment, processor 210 may include one or more CPUs, such as CPU0 and CPU1 of FIG. 3.

In a particular implementation, referring to FIG. 3, as an example, the crystal pulling control apparatus 200 may include a plurality of processors 210, such as the processor 210 and the processor 250 of FIG. 3. Each of these processors may be a single-core processor or a multi-core processor.

The embodiment of the invention also provides a computer readable storage medium. The computer readable storage medium has instructions stored therein that, when executed, implement the functions performed by the crystal pulling control device in the above-described embodiments.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions is loaded and executed on a computer, the processes or functions of embodiments of the present invention are performed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, a terminal, a user equipment, or other programmable apparatus. The computer program or instructions may be stored in or transmitted from one computer readable storage medium to another, for example, by wired or wireless means from one website site, computer, server, or data center. Computer readable storage media can be any available media that can be accessed by a computer or data storage devices such as servers, data centers, etc. that integrate one or more available media. Usable media may be magnetic media such as floppy disks, hard disks, magnetic tape; optical media, such as digital video discs (digital video disc, DVD); but also semiconductor media such as solid state disks (solid state drive, SSD).

Although the invention is described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Although the invention has been described in connection with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are merely exemplary illustrations of the present invention as defined in the appended claims and are considered to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. The crystal remelting control method is characterized by being applied to a crystal pulling furnace, wherein the crystal pulling furnace comprises a crucible lifting device, a crystal pulling device and a heater, the crucible lifting device is used for adjusting the crucible position of a crucible, and the crucible is used for containing melt; the crystal remelting control method comprises the following steps:

under the condition of broken line of the crystal, controlling the crucible lifting device to descend the crucible from the broken line crucible position of the crystal to the crucible position of the crystal return;

when the crucible descends to the crucible position where the crystal returns to the crucible position, controlling the crystal pulling device to adjust the position of the crystal so that the crystal contacts with the liquid level of the melt;

when the crystal is in contact with the liquid level of the melt, controlling the heater to carry out the remelting operation on the crystal;

determining that the crystal is converted into a melt under the condition that the exothermic amount of the heater is larger than or equal to the reflow endothermic amount of the crystal according to the crystal endothermic parameter and the heater exothermic parameter;

in the case of broken crystal, before the heater is controlled to perform the reflow operation on the crystal, the crystal reflow control method further includes: controlling the heater to adjust the power from the wire-break heating power to the crystal melting back power; the broken wire heating power and the crystal reflow power are in linear change.

2. The crystal remelting control method of claim 1 wherein controlling the crucible lifting device to lower the crucible from a crystal breakage crucible position to a crystal reflow crucible position comprises:

controlling the crucible lifting device to descend the crucible from the broken line crucible position to the crucible preheating position, and controlling the heater to preheat the crucible which descends to the crucible preheating position;

and controlling the crucible lifting device to lower the crucible from the crucible preheating crucible position to the crystal return crucible position.

3. The crystal remelting control method of claim 2 wherein controlling the crucible lifting device to lower the crucible from a crystal breakage crucible position to a crucible preheating crucible position comprises:

controlling the crucible lifting device to descend the crucible from the crucible position of the broken line of the crystal;

and acquiring the actual crucible position of the crucible, and controlling the heater to preheat the crucible under the condition that the actual crucible position of the crucible is the crucible preheating position.

4. The crystal remelting control method of claim 2 wherein controlling the crucible lifting device to lower the crucible from a crucible-preheating crucible position to a crystal-remelting crucible position comprises:

Controlling the crucible lifting device to descend the crucible from the crucible preheating position;

and acquiring the actual crucible position of the crucible, and determining that the actual crucible position of the crucible is equal to the crystal crucible returning position of the crucible under the condition that the actual crucible position of the crucible is lower than or equal to the initial crucible returning position of the crystal.

5. The crystal remelting control method of claim 4 wherein the initial reflow crucible position is determined by a seeding crucible position height and a first crucible position correction parameter; wherein,

the initial crucible return = the seeding crucible level height-the first crucible level correction parameter; and/or the number of the groups of groups,

the correction parameter of the first crucible position is 5 mm-40 mm.

6. The crystal reflow control method of claim 2, wherein the crucible pre-heat crucible position is determined by the crystal breakage crucible position and a second crucible position correction parameter; wherein,

the crucible preheating crucible position = the crystal breakage crucible position height-the second crucible position correction parameter; and/or the number of the groups of groups,

the correction parameter of the second crucible position is 20 mm-60 mm.

7. The crystal reflow control method of claim 1, wherein the time taken to control the heater to adjust power from off-line heating power to crystal reflow power is between 5s and 600s.

8. The crystal reflow control method of claim 1, wherein the crystal has a first crystal section proximate the liquid level and a second crystal section distal the liquid level, the second crystal section having a length less than the length of the first crystal section;

wherein,

and the crystal remelting power of the heater in the first crystal section is larger than that of the heater in the second crystal section.

9. The crystal reflow control method of claim 8, wherein the heater's crystal reflow power at the first die is determined by seeding power and a first power correction parameter; wherein,

the crystal reflow power of the heater at the first crystal section=seeding power+first correction power parameter; the first correction power parameter is 10 kw-25 kw; and/or the number of the groups of groups,

the crystal reflow power of the heater at the second crystal section is determined by the seeding power and a second power correction parameter; wherein,

the crystal reflow power of the heater at the second crystal section=seeding power+second correction power parameter, and the second correction power parameter is 0 kw-10 kw.

10. The crystal reflow control method of any of claims 1-6, wherein controlling the heater to reflow the crystal includes:

Controlling the crystal to perform sectional remelting operation according to the sectional remelting parameters;

and under the condition that the exothermic amount of the heater is larger than or equal to the reflow heat absorption amount of the crystal according to the crystal endothermic parameter and the heater exothermic parameter, determining that the crystal is converted into a melt, wherein the method comprises the following steps:

determining the subsection remelting heat absorption quantity of the crystal according to the subsection remelting parameters;

determining the theoretical time length of the crystal section remelting according to the heat absorption quantity of the crystal section remelting and the heat release parameter of the heater;

11. The crystal reflow control method of claim 10, wherein the segment reflow parameters are segment reflow lengths, the segment reflow lengths being the lengths of the crystal that each extend into the melt; when the crystal has a first crystal section close to the liquid level and a second crystal section far away from the liquid level, the diameter of the first crystal section is larger than that of the second crystal section; wherein,

the segmented reflow length of the second crystal section is 1-3 times of the segmented reflow length of the first crystal section; and/or the number of the groups of groups,

The segmented remelting length is 20-40 mm.

12. The crystal reflow control method of any of claims 1-6, wherein the crystal endothermic parameters include a crystal melting parameter and a crystal crystallization latent heat parameter; wherein,

the crystal melting parameters comprise the mass of the crystal, the specific heat of the crystal and the temperature variation;

the crystal crystallization latent heat parameter comprises the heat of fusion of the crystal and the mole number of the crystal;

the heater heat release parameters include power and heating time of the heater.

13. The crystal remelting control method according to any one of claims 1 to 6, wherein during the remelting operation, a crystal rotation of the crystal pulling furnace is 3 to 7 rotations/min, and/or a crucible rotation of the crystal pulling furnace is 0.5 to 4 rotations/min.

14. A crystal pulling control apparatus, comprising: a processor and a communication interface coupled to the processor for executing a computer program or instructions to implement the crystal reflow control method of any of claims 1-13.

15. A crystal pulling furnace comprising a crucible lifting device, a crystal pulling device, a heater, and the crystal pulling control apparatus of claim 14, the crystal pulling control apparatus in communication with the crucible lifting device, the crystal pulling device, and the heater.

16. A computer storage medium having instructions stored therein which, when executed, implement the crystal reflow control method of any one of claims 1-13.