A finishing process for improving the success rate of finishing

Abstract

The application discloses a tailing process for improving tailing success rate, which precisely controls the temperature change of a growth interface, tailing shape, and ensures that the diameter cannot be reduced or the tailing is broken due to too low or too high temperature rising trend by controlling seven parameters, specifically by reducing the crucible rotation, reducing the furnace pressure, reducing the power, reducing the crystal rotation, reducing the argon flow, increasing the pulling speed, and reducing the crucible lifting, so that the tailing success rate is above 90%.

Description

Technical Field

[0001] This invention relates to the field of monocrystalline silicon production technology, and in particular to a finishing process that improves the success rate of finishing. Background Technology

[0002] In the production of monocrystalline silicon rods, the main processes include furnace dismantling, charging, melting, temperature adjustment, crystal pulling, shoulder setting, shoulder rotation, equal diameter setting, finishing, and furnace shutdown.

[0003] The finishing process is a crucial step, concluding the pulling of a single crystal ingot. After the constant-diameter section is completed and the crystal tail detaches from the molten silicon, thermal stress can cause dislocations to form, which then extend upwards. To avoid this, a finishing process is employed to reduce the area of ​​thermal stress acting on the crystal tail, preventing dislocation formation and improving the crystallization rate of the single crystal.

[0004] The existing process involves raising the temperature of the thermal field to reduce the diameter of the crystal rod. When the diameter is reduced to a certain extent, it is directly broken off. However, there is a risk of wire breakage at the end of the process, which can lead to failure in the final stage. Summary of the Invention

[0005] In view of this, the present invention provides a finishing process to improve the success rate of finishing, thereby solving the problem of low success rate of finishing processes in existing processes.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A finishing process to improve the success rate of finishing work includes:

[0008] In the early stages of the final stage, the heater power is increased by a moderate amount, the crystal pulling speed is reduced, the crucible lifting is stopped, the crucible rotation is reduced, the crystal rotation is reduced, the furnace pressure is reduced, and the argon flow rate is reduced, so that the crystal diameter will not shrink immediately when entering the final stage.

[0009] In the mid-stage of the process, the heater power is slightly increased, the crystal pulling speed is increased, and the crucible rotation is reduced, causing the thermal field to begin to heat up and the crystal diameter to shrink rapidly.

[0010] In the final stage, the heater power is significantly increased, the crystal pulling speed is increased, and the crucible rotation is reduced, so that the thermal field temperature continues to increase, the crystal grows rapidly, and the crystal diameter is reduced to the final state. The crystal is then lifted out of the liquid surface to complete the final stage.

[0011] Preferably, the medium-amplitude increase in heater power is an increase of 8-10KW from the equal-diameter power, the small-amplitude increase in heater power is an increase of 4-6KW from the initial stage, and the large-amplitude increase in heater power is an increase of 13-15KW from the intermediate stage.

[0012] Preferably, the medium-amplitude increase in heater power is achieved by increasing the equal-diameter power by 9KW, the small-amplitude increase in heater power is achieved by increasing it by 5KW again from the initial stage, and the large-amplitude increase in heater power is achieved by increasing it by 14KW again from the intermediate stage.

[0013] Preferably, in the early stage of the finishing process, the crystal pulling speed is reduced from 83 mm / hr to 75 mm / hr, the crucible lifting speed is reduced from 0.2 mm / hr to 0, the crucible rotation speed is reduced from 8 rpm to 6.5 rpm after a period of time, the crystal rotation speed is reduced from 8 rpm to 7 rpm after a period of time, the furnace pressure is reduced from 13 torr to 11 torr, and the argon flow rate is reduced from 100 slpm to 80 slpm.

[0014] Preferably, during the final stage, the crystal pulling speed is increased from 75 mm / hr to 107 mm / hr, the crucible lifting speed is kept at 0, and the crucible rotation speed is reduced from 6.5 rpm to 4.5 rpm.

[0015] Preferably, during the final stage, the crystal rotation is maintained at 7 rpm, the furnace pressure is maintained at 11 torr, and the argon flow rate is maintained at 80 slpm.

[0016] Preferably, in the later stage of the finishing process, the body pulling speed is reduced from 107 mm / hr to 255 mm / hr, the crucible lifting speed is kept at 0, and the crucible rotation speed is reduced from 4.5 rpm to 2 rpm.

[0017] Preferably, the crystal rotation is maintained at 7 rpm, the furnace pressure is maintained at 11 torr, and the argon flow rate is maintained at 80 slpm.

[0018] Preferably, the early stage of finishing corresponds to a finishing length of 0-80mm, the middle stage of finishing corresponds to a finishing length of 80-160mm, and the late stage of finishing corresponds to a finishing length of 160-240mm.

[0019] Preferably, in the final stage of the process, the crystal diameter is reduced to a final state of 25-30 mm.

[0020] As can be seen from the above technical solution, the finishing process provided by the present invention, which improves the success rate of finishing, controls seven parameters: specifically by reducing crucible rotation, reducing furnace pressure, reducing power, reducing crystal rotation, reducing argon flow rate, increasing pulling speed, and reducing crucible rise, to precisely control the temperature change of the growth interface and the finishing shape. At the same time, it ensures that the diameter cannot be reduced or the finishing line is broken due to the temperature rising trend being too low or too high, and the finishing success rate reaches more than 90%. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic flowchart of a finishing process to improve the success rate of finishing, provided in an embodiment of the present invention. Detailed Implementation

[0023] This invention discloses a finishing process to improve the success rate of finishing work. This process controls seven parameters, specifically:

[0024] In the early stages, increase the heater power, reduce the pulling speed, stop the crucible lifting, reduce the crucible rotation, reduce the furnace pressure, and reduce the argon flow rate to ensure that the crystal diameter will not shrink immediately when entering the final stage, and to ensure a smooth transition from the constant diameter stage to the final stage, while also buffering the temperature rise in the middle and later stages of the constant diameter stage.

[0025] In the middle stage, the heater power is increased, the crystal pulling speed is increased, and the crucible rotation is reduced, so that the thermal field begins to heat up and the crystal rod diameter is rapidly reduced;

[0026] Later, the power was increased significantly and the crystal pulling speed was increased. The crucible speed was reduced to 2 rpm, the thermal field temperature continued to increase, the crystal grew rapidly, and the crystal diameter was reduced to 25-30 mm. The crystal was then lifted out of the liquid surface, completing the process.

[0027] This solution achieves a success rate of over 90% by precisely controlling the temperature changes at the growth interface and the shape of the terminal section, while ensuring that the diameter reduction is not achieved or the terminal section breaks due to excessively low or high temperature rise.

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The finishing process for improving the success rate of finishing provided in this embodiment of the invention includes:

[0030] In the early stages of the final stage, the heater power is increased by a moderate amount, the crystal pulling speed is reduced, the crucible lifting is stopped, the crucible rotation is reduced, the crystal rotation is reduced, the furnace pressure is reduced, and the argon flow rate is reduced, so that the crystal diameter will not shrink immediately when entering the final stage.

[0031] In the mid-stage of the process, the heater power is slightly increased, the crystal pulling speed is increased, and the crucible rotation is reduced, causing the thermal field to begin to heat up and the crystal diameter to shrink rapidly.

[0032] In the final stage, the heater power is significantly increased, the crystal pulling speed is increased, and the crucible rotation is reduced, so that the thermal field temperature continues to increase, the crystal grows rapidly, and the crystal diameter is reduced to the final state. The crystal is then lifted out of the liquid surface to complete the final stage.

[0033] As can be seen from the above technical solutions, the finishing process for improving the success rate of finishing provided by the embodiments of the present invention controls seven parameters: specifically by reducing crucible rotation, reducing furnace pressure, reducing power, reducing crystal rotation, reducing argon flow rate, increasing pulling speed, and reducing crucible rise, to precisely control the temperature change of the growth interface and the finishing shape, while ensuring that the diameter cannot be reduced or the finishing line is broken due to the temperature rising trend being too low or too high, and the finishing success rate reaches more than 90%.

[0034] Furthermore, the intermediate increase in heater power is achieved by increasing the equal-diameter power by 8-10KW (preferably 9KW), the slight increase in heater power is achieved by increasing it again by 4-6KW (preferably 5KW) from the initial stage, and the significant increase in heater power is achieved by increasing it again by 13-15KW (preferably 14KW) from the middle stage, thereby providing a reasonable temperature increase gradient for the entire finishing process.

[0035] Preferably, in the early stage of the finishing process, the crystal pulling speed is reduced from 83 mm / hr to 75 mm / hr, the crucible lifting speed is reduced from 0.2 mm / hr to 0, the crucible rotation speed is reduced from 8 rpm to 6.5 rpm after a period of time, the crystal rotation speed is reduced from 8 rpm to 7 rpm after a period of time, the furnace pressure is reduced from 13 torr to 11 torr, and the argon flow rate is reduced from 100 slpm to 80 slpm. This ensures that the crystal diameter will not shrink immediately when entering the finishing stage, and guarantees a smooth transition from the constant diameter stage to the finishing stage, while also buffering the temperature rise in the later stages of the constant diameter stage.

[0036] During the final stage, the crystal pulling speed was increased from 75 mm / hr to 107 mm / hr, the crucible height was kept at 0, and the crucible rotation was reduced from 6.5 rpm to 4.5 rpm, causing the thermal field to start heating up and the crystal rod diameter to shrink rapidly. Similar to the previous stage, the crystal rotation was kept at 7 rpm, the furnace pressure was kept at 11 torr, and the argon flow rate was kept at 80 slpm.

[0037] In the final stage, the body pulling speed was reduced from 107 mm / hr to 255 mm / hr, the crucible lifting was kept at 0, the crucible rotation was reduced from 4.5 rpm to 2 rpm, the thermal field temperature continued to increase, and the crystal grew rapidly; similar to the middle stage, the crystal rotation was kept at 7 rpm, the furnace pressure was kept at 11 torr, and the argon flow rate was kept at 80 slpm.

[0038] The early stage of finishing corresponds to a finishing length of 0-80mm, the middle stage of finishing corresponds to a finishing length of 80-160mm, and the late stage of finishing corresponds to a finishing length of 160-240mm.

[0039] In the final stage, the crystal diameter is reduced to a final state of 25-30 mm.

[0040] The following is a further description of this solution with reference to specific embodiments:

[0041] The process of this plan can be referred to Figure 1 As shown:

[0042] ① Early stage (tailing length 0-80mm): The heater power is increased by 9KW from the equal diameter stage, the crystal pulling speed is reduced from 83mm / hr to 75mm / hr, the crucible lifting speed is reduced from 0.2mm / hr to 0, the crucible rotation speed is reduced from 8rpm to 6.5rpm after a period of time (specifically until the tailing length is 80mm), the crystal rotation speed is reduced from 8rpm to 7rpm after a period of time (specifically until the tailing length is 40mm), the furnace pressure is reduced from 13torr to 11torr, and the argon flow rate is reduced from 100slpm to 80slpm. Under these parameters, the crystal diameter will not shrink immediately when entering the tailing stage, ensuring a smooth transition from the equal diameter stage to the tailing stage, and buffering the temperature rise in the later stages of the equal diameter stage.

[0043] ② Mid-term (80-160mm): The heater power is increased by 5KW again from the early stage, the crystal pulling speed is reduced from 75mm / hr to 107mm / hr, the crucible rise is kept at 0, the crucible rotation is reduced from 6.5rpm to 4.5rpm, the crystal rotation is kept at 7rpm, the furnace pressure is kept at 11torr, and the argon flow rate is kept at 80slpm; under these parameters, the crystal diameter is rapidly reduced.

[0044] ③ Later stage (160-240mm): The heater power is increased again by 14KW from the middle stage, the crystal pulling speed is reduced from 107mm / hr to 255mm / hr, the crucible rise is kept at 0, the crucible rotation speed is reduced from 4.5rpm to 2rpm, the crystal rotation speed is kept at 7rpm, the furnace pressure is kept at 11torr, and the argon flow rate is kept at 80slpm; under these parameters, the crystal grows rapidly, and the crystal diameter is reduced to 25-30mm. The crystal is then lifted out of the liquid surface, completing the final stage.

[0045] This process controls seven parameters: specifically, by reducing crucible rotation, furnace pressure, power, crystal rotation, and argon flow rate, increasing pulling speed, and reducing crucible rise, to precisely control the temperature change at the growth interface and the shape of the tail. At the same time, it ensures that the diameter cannot be reduced or the tail breaks due to the temperature rise being too low or too high, and the success rate of the tail is over 90%.

[0046] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A finishing process to improve the success rate of finishing, characterized in that, By controlling heater power, crystal pulling speed, crucible rise, crucible rotation, crystal rotation, furnace pressure, and argon flow rate in stages, the end-of-line disconnection during the final stage is avoided, including: In the early stages of the final stage, the heater power is increased by a moderate amount, the crystal pulling speed is reduced, the crucible lifting is stopped, the crucible rotation is reduced, the crystal rotation is reduced, the furnace pressure is reduced, and the argon flow rate is reduced, so that the crystal diameter will not shrink immediately when entering the final stage. In the mid-stage of the process, the heater power is slightly increased, the crystal pulling speed is increased, and the crucible rotation is reduced, causing the thermal field to begin to heat up and the crystal diameter to shrink rapidly. In the final stage, the heater power is significantly increased, the crystal pulling speed is increased, and the crucible rotation is reduced, so that the thermal field temperature continues to increase, the crystal grows rapidly, and the crystal diameter is reduced to the final state. The crystal is then lifted out of the liquid surface to complete the final stage. The medium-amplitude increase in heater power is an increase of 8-10KW from the equal-diameter power; the small-amplitude increase in heater power is an increase of 4-6KW from the initial stage; and the large-amplitude increase in heater power is an increase of 13-15KW from the intermediate stage. In the early stage of the final stage, the crystal pulling speed was reduced from 83 mm / hr to 75 mm / hr, the crucible lifting speed was reduced from 0.2 mm / hr to 0, the crucible rotation speed was reduced from 8 rpm to 6.5 rpm after a period of time, the crystal rotation speed was reduced from 8 rpm to 7 rpm after a period of time, the furnace pressure was reduced from 13 torr to 11 torr, and the argon flow rate was reduced from 100 slpm to 80 slpm.

2. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, The medium-amplitude increase in heater power is achieved by increasing the equal-diameter power by 9KW; the small-amplitude increase in heater power is achieved by increasing it by 5KW again from the initial stage; and the large-amplitude increase in heater power is achieved by increasing it by 14KW again from the intermediate stage.

3. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, During the final stage, the crystal pulling speed was increased from 75 mm / hr to 107 mm / hr, the crucible lifting speed was kept at 0, and the crucible rotation speed was reduced from 6.5 rpm to 4.5 rpm.

4. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, During the final stage, the crystal rotation speed was maintained at 7 rpm, the furnace pressure at 11 torr, and the argon flow rate at 80 slpm.

5. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, During the final stage of the process, the crystal pulling speed was increased from 107 mm / hr to 255 mm / hr, the crucible lifting speed was kept at 0, and the crucible rotation speed was reduced from 4.5 rpm to 2 rpm.

6. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, During the final stage, the crystal rotation speed was maintained at 7 rpm, the furnace pressure at 11 torr, and the argon flow rate at 80 slpm.

7. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, The early stage of finishing corresponds to a finishing length of 0-80mm, the middle stage of finishing corresponds to a finishing length of 80-160mm, and the late stage of finishing corresponds to a finishing length of 160-240mm.

8. The finishing process for improving the success rate of finishing according to claim 1, characterized in that, In the final stage, the crystal diameter is reduced to a final state of 25-30 mm.

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