阅读说明：本技术 控制单晶硅尾部长度的方法及单晶炉收尾方法 (Method for controlling tail length of monocrystalline silicon and ending method of monocrystalline furnace ) 是由 梁万亮 丁亚国 马国忠 顾燕滨 河野贵之 于 2020-12-24 设计创作，主要内容包括：本发明提供一种控制单晶硅尾部长度的方法及单晶硅收尾方法,属于单晶硅生产技术领域。读取实时收尾长度L-1以及该收尾长度对应的实际收尾重量W-1,并通过实时收尾长度L-1计算理论收尾重量W-0,比较实际收尾重量W-1与理论收尾重量W-0的偏差,如果偏差过大,则对应的调整实时收尾长度L-1时刻的拉晶拉速或收尾温度,以降低实际收尾重量W-1与理论收尾重量W-0的偏差,达到控制单晶硅硅棒尾部长度的目的,避免单晶硅硅棒尾部过长,导致收尾用料较多,且收尾时间长,或者单晶硅硅棒尾部过短,造成位错,使晶体失去完整单晶结构。同时,控制单晶硅硅棒尾部长度,也能够为成批次生产特殊要求的单晶硅硅棒提供可靠的收尾控制参数。(The invention provides a method for controlling tail length of monocrystalline silicon and a monocrystalline silicon ending method, belonging to the technical field of monocrystalline silicon production. Reading real-time tail length L 1 And an actual final weight W corresponding to the final length 1 And by real-time ending length L 1 Calculating theoretical ending weight W 0 Comparing the actual ending weight W 1 And theoretical ending weight W 0 If the deviation is too large, the real-time ending length L is correspondingly adjusted 1 The pull rate or the end temperature of the crystal at the moment to reduce the actual end weight W 1 And theoretical ending weight W 0 The deviation of the length of the tail part of the monocrystalline silicon rod is controlled, the problems that the tail part of the monocrystalline silicon rod is too long, the tail materials are more, the tail time is long, or the tail part of the monocrystalline silicon rod is too short, dislocation is caused, and the crystal loses a complete monocrystalline structure are avoided. Meanwhile, the length of the tail part of the monocrystalline silicon rod can be controlledCan provide reliable ending control parameters for batch secondary production of the monocrystalline silicon rods with special requirements.)

1. A method for controlling the tail length of monocrystalline silicon is characterized by comprising the following steps:

a. reading real-time tail length L₁And an actual final weight W corresponding to the final length₁；

b. Calculating theoretical ending weight W₀：

Where ρ is_GIs the density of the monocrystalline silicon, D is the equal diameter of the monocrystalline silicon rod, D₁For a real-time ending length L₁The theoretical diameter of the tail of the monocrystalline silicon is measured;

c. calculating the weight deviation rate eta:

d. comparing the absolute value | eta | of the weight deviation ratio with a preset deviation ratio threshold eta₀When eta |. does not exist>η₀Adjusting the real-time ending length L₁The pull rate or the end temperature at the time such that eta e < -eta ∈₀，η₀]Wherein η₀>0；

e. And c, repeating the steps a to d at preset crystal pulling length delta L intervals, and controlling the tail length of the monocrystalline silicon.

2. The method of controlling tail length of single crystal silicon as claimed in claim 1, wherein in step d, said "adjusting real time tail length L" adjusts real time tail length L₁The pull rate and the ending temperature of the crystal pulling at the moment comprise the following steps:

d1. when eta<-η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is increased by 1 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is increased by 1 to 25 percent;

d2. when eta>η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is reduced by 1 to 25 percent, or the real-time ending length L is reduced₁The ending temperature at the moment is reduced by 1 to 25 percent.

3. The method of controlling the tail length of single crystal silicon as claimed in claim 2,

in step d1, when η<-η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is increased by 5 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is increased by 5 to 25 percent;

in step d2, when η>η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is reduced by 5 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is reduced by 5 to 25 percent.

4. The method of controlling tail length of single crystal silicon as claimed in claim 1, wherein the real time tail length L of two adjacent reads₁The difference value is more than or equal to 1mm, and the delta L is less than or equal to 30 mm.

5. The method of controlling tail length of single crystal silicon as claimed in claim 4, wherein real time tail length L of two adjacent reads₁The difference value of delta L is more than or equal to 10mm and less than or equal to 30 mm.

6. The method of controlling the tail length of single crystal silicon as claimed in claim 1, wherein η₀≤0.15。

7. The method of controlling the tail length of single crystal silicon as claimed in claim 6, wherein η₀≤0.05。

8. A single crystal furnace ending method is used for controlling the tail length of a silicon single crystal rod and is characterized in that: the method comprises the following steps:

performing first ending according to the preset ending parameters, adjusting the preset ending parameters according to the method for controlling the length of the tail part of the monocrystalline silicon according to any one of claims 1 to 7, and obtaining first adjusting parameters after ending the ending to obtain a first monocrystalline silicon rod;

judging whether the tail length of the first monocrystalline silicon rod meets the requirement, if so, taking the first adjustment parameter as a final parameter, and putting into production; if not, the following method is executed:

performing Nth ending according to the (N-1) th adjusting parameter, adjusting the (N-1) th adjusting parameter according to the method for controlling the length of the tail part of the monocrystalline silicon according to any one of claims 1 to 7, and obtaining the Nth adjusting parameter after ending the ending to obtain the Nth monocrystalline silicon rod, wherein N is an integer more than or equal to 2;

and judging whether the tail length of the Nth monocrystalline silicon rod meets the requirement, and if so, taking the Nth adjustment parameter as a final parameter to put into production.

Technical Field

The invention belongs to the technical field of monocrystalline silicon production, and particularly relates to a method for controlling tail length of monocrystalline silicon and a monocrystalline silicon ending method.

Background

The crystal is directly separated from the liquid level after the process of crystal pulling equal diameter is finished, the grown dislocation-free single crystal receives thermal shock, and dislocation can be generated when the thermal stress is larger than the critical stress of silicon, so that the crystal loses a complete single crystal structure, the crystal is required to be terminated after the equal diameter is finished, the crystal is slowly separated from the liquid level, and the dislocation generated when the generated single crystal is subjected to the thermal shock is avoided. The length of the ending is generally close to the diameter of the same diameter, and is greater or smaller than the diameter of the same diameter.

In the prior art, a crystal pulling ending process is mainly carried out by adopting a preset ending process through a control system. For example, chinese patent No. 201610375021.9 discloses an automatic ending method for a Z-80 single crystal furnace, which sets a single crystal pulling rate and a temperature correction value at the beginning of the ending of the single crystal, and adjusts the pulling rate and the temperature correction value according to the variation of the ending length of the single crystal before the ending of the single crystal. For another example, chinese patent No. 201910977065.4 discloses a method for ending a single crystal furnace, which can improve the success rate of ending, by repeatedly measuring the shape of the ending tail and correspondingly adjusting the ending process according to the change of the shape of the tail, the tail of the single crystal silicon with regular shape can be obtained.

However, the above ending process cannot control the length of the tail of the single crystal silicon, and if the ending length is too long, the ending materials are more and the ending time is long; although the reduction of the ending length is beneficial to reducing ending materials, improving the yield, reducing the ending time, reducing the consumption of electricity, argon and the like, the dislocation is easily generated when the ending length is too short, so that the crystal loses the complete single crystal structure. Meanwhile, in some special occasions, different thermal histories of the tail of the crystal bar are needed, and the tail length may change according to actual requirements, so that the tail length of the monocrystalline silicon needs to be controlled.

Disclosure of Invention

In view of this, the present invention provides a method for controlling the length of the tail of the single crystal silicon, so as to solve the technical problem in the prior art that the length of the tail of the single crystal silicon cannot be effectively controlled.

The invention also provides a single crystal furnace ending method for obtaining the silicon single crystal rod with the equivalent tail length.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a method of controlling the tail length of single crystal silicon, comprising the steps of:

a. reading real-time tail length L₁And an actual final weight W corresponding to the final length₁；

b. Calculating theoretical ending weight W₀：

Where ρ is_GIs the density of the monocrystalline silicon, D is the equal diameter of the monocrystalline silicon rod, D₁For a real-time ending length L₁The theoretical diameter of the tail of the monocrystalline silicon is measured;

c. calculating the weight deviation rate eta:

d. comparing the absolute value | eta | of the weight deviation ratio with a preset deviation ratio threshold eta₀When eta |. does not exist>η₀Adjusting the real-time ending length L₁The pull rate or the end temperature at the time such that eta e < -eta ∈₀，η₀]Wherein η₀>0；

e. And c, repeating the steps a to d at preset crystal pulling length delta L intervals, and controlling the tail length of the monocrystalline silicon.

Preferably, in step d, the "adjusting the real-time ending length L₁The pull rate and the ending temperature of the crystal pulling at the moment comprise the following steps:

d1. when eta<-η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is increased by 1 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is increased by 1 to 25 percent;

d2. when eta>η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is reduced by 1 to 25 percent, or the real-time ending length L is reduced₁The ending temperature at the moment is reduced by 1 to 25 percent.

Preferably, in step d1, when η<-η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is increased by 5 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is increased by 5 to 25 percent; in step d2, when η>η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is reduced by 5 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is reduced by 5 to 25 percent.

Preferably, the real-time tail length L of two adjacent reads₁The difference value is more than or equal to 1mm, and the delta L is less than or equal to 30 mm.

Preferably, the real-time tail length L of two adjacent reads₁The difference value of delta L is more than or equal to 10mm and less than or equal to 30 mm.

Preferably, eta₀≤0.15。

Preferably, eta₀≤0.05。

A single crystal furnace ending method is used for controlling the tail length of a silicon single crystal rod and comprises the following steps:

according to the preset ending parameters, carrying out first ending, adjusting the preset ending parameters according to the method for controlling the length of the tail part of the monocrystalline silicon, and after ending, obtaining first adjusting parameters to obtain a first monocrystalline silicon rod;

judging whether the tail length of the first monocrystalline silicon rod meets the requirement, if so, taking the first adjustment parameter as a final parameter, and putting into production; if not, the following method is executed:

performing Nth ending according to the (N-1) th adjusting parameter, adjusting the (N-1) th adjusting parameter according to the method for controlling the length of the tail part of the monocrystalline silicon, and obtaining the Nth adjusting parameter after ending the ending to obtain an Nth monocrystalline silicon rod, wherein N is an integer more than or equal to 2;

and judging whether the tail length of the Nth monocrystalline silicon rod meets the requirement, and if so, taking the Nth adjustment parameter as a final parameter to put into production.

According to the technical scheme, the invention provides a method for controlling the tail length of monocrystalline silicon, which has the beneficial effects that: reading real-time tail length L₁And an actual final weight W corresponding to the final length₁And by real-time ending length L₁Calculating theoretical ending weight W₀Comparing the actual ending weight W₁And theoretical ending weight W₀If the deviation is too large, the real-time ending length L is correspondingly adjusted₁The pull rate or the end temperature of the crystal at the moment to reduce the actual end weight W₁And theoretical ending weight W₀The deviation of the length of the tail part of the monocrystalline silicon rod is controlled, the problems that the tail part of the monocrystalline silicon rod is too long, the tail materials are more, the tail time is long, or the tail part of the monocrystalline silicon rod is too short, dislocation is caused, and the crystal loses a complete monocrystalline structure are avoided. Meanwhile, the tail length of the monocrystalline silicon rod is controlled, and reliable ending control parameters can be provided for batch secondary production of monocrystalline silicon rods with special requirements.

The invention also provides a monocrystalline silicon ending method, which realizes the controllable length of the tail part of the monocrystalline silicon rods in the same batch or similar batches, and avoids the problems that the tail part of the monocrystalline silicon rod is too long, the ending materials are more, the ending time is long, or the tail part of the monocrystalline silicon rod is too short, the dislocation is caused, and the crystal loses the complete monocrystalline structure. Meanwhile, the tail length of the monocrystalline silicon rod is controlled, and reliable ending control parameters can be provided for batch secondary production of monocrystalline silicon rods with special requirements.

Drawings

Fig. 1 is a reference schematic diagram of a method of controlling the length of a tail of single crystal silicon.

Detailed Description

The technical scheme and the technical effect of the invention are further elaborated in the following by combining the drawings of the invention.

Referring to fig. 1, in one embodiment, a method for controlling tail length of single crystal silicon comprises the steps of:

a. reading real-time tail length L₁And an actual final weight W corresponding to the final length₁. That is, a predetermined ending parameter is used to perform ending, and during the ending process, the real-time ending length L can be obtained by the control system of the existing Czochralski crystal growing furnace₁And an actual final weight W corresponding to the final length₁。

b. Calculating theoretical ending weight W₀：

Where ρ is_GIs the density of the monocrystalline silicon, D is the equal diameter of the monocrystalline silicon rod, D₁For a real-time ending length L₁The theoretical diameter of the tail of the monocrystalline silicon.

Specifically, assuming that the theoretical tail shape of the tail is a regular taper, for example, the expected tail length of a silicon single crystal rod to be obtained is L₀According to the expected ending length L₀And pulling the constant diameter D to obtain the expected tail angle theta₀＝arctan(2L₀/D)。

When the length L is finished in real time₁During the process, the theoretical tail of the monocrystalline silicon crystal rod is in a shape of a circular truncated cone, the bottom diameter of the circular truncated cone is the equal diameter D of the silicon rod, and the upper theoretical diameterThe theoretical ending weight W can be calculated by formula I₀。

c. Calculating the weight deviation rate eta:

d. comparing the absolute value | eta | of the weight deviation ratio with a preset deviation ratio threshold eta₀When eta |. does not exist>η₀Adjusting the real-time ending length L₁The pull rate or the end temperature at the time such that eta e < -eta ∈₀，η₀]Wherein η₀>0。

Specifically, when the actual ending weight W₁Weight greater than theoretical final weight W₀Time, i.e. the rate of weight deviation eta>When the weight deviation ratio η is too large, the final length of the tail of the monocrystalline silicon and the theoretical deviation value are increased, and then the final ending parameter needs to be adjusted. For example, when eta>η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is increased by 1 to 25 percent, or the real-time ending length L is adjusted₁The ending temperature at the moment is increased by 1-25 percent, so that the ending speed is increased. As another example, when eta<-η₀In time, the real-time ending length L₁The pulling speed of the crystal pulling at the moment is reduced by 1 to 25 percent, or the real-time ending length L is reduced₁The ending temperature at the moment is reduced by 1-25 percent so as to slow the ending speed.

e. And c, repeating the steps a to d at preset crystal pulling length delta L intervals, and controlling the tail length of the monocrystalline silicon.

Specifically, repeating steps a-d at intervals of a predetermined crystal pulling length Delta L to obtain the real-time ending length L again₁And an actual final weight W corresponding to the final length₁And judging and adjusting the ending rate at the moment to enable the tail length of the monocrystalline silicon rod to be towards the expected tail length L₀Close.

In the method, the real-time ending length L is read₁And an actual final weight W corresponding to the final length₁And by real-time ending length L₁Calculating theoretical ending weight W₀Comparing the actual ending weight W₁And theoretical ending weight W₀If the deviation is too large, the real-time ending length L is correspondingly adjusted₁The pull rate or the end temperature of the crystal at the moment to reduce the actual end weight W₁And theoretical ending weight W₀The deviation of the length of the tail part of the monocrystalline silicon rod is controlled, the problems that the tail part of the monocrystalline silicon rod is too long, the tail materials are more, the tail time is long, or the tail part of the monocrystalline silicon rod is too short, the dislocation is caused, and the crystal is lost are solvedA complete single crystal structure. Meanwhile, the tail length of the monocrystalline silicon rod is controlled, and reliable ending control parameters can be provided for batch secondary production of monocrystalline silicon rods with special requirements.

It should be noted that the above adjustment process can be completed by manual adjustment or by cooperating with a computer software program.

When the manual regulation is completed, the regulation frequency of the ending parameters is moderate, the regulation amplitude is moderate, the regulation frequency or the regulation amplitude is too large, the ending process fluctuation is easily caused, ending failure is caused, and the regulation frequency or the regulation amplitude is too small, so that the tail part of the monocrystalline silicon rod has large deviation during regulation and the regulation effect is not good. For example, in the case of manual adjustment, the determination adjustment is performed once every 10mm to 30mm at a predetermined pull length Δ L, the adjustment width of the pull rate or the ending temperature corresponding to each time is 5% to 25%, and the allowable deviation ratio threshold η is set for each adjustment₀Larger, e.g. 0.05 ≦ η₀≤0.15。

When the method is matched with a computer software program, the adjusting frequency of the ending parameters can be improved, the adjusting amplitude can be reduced, so that small-amplitude and multiple-time adjustment can be realized, and the optimal ending parameters can be obtained by fewer times. For example, when adjusting in accordance with a computer software program, the judgment adjustment is performed once every predetermined pull length Δ L of 1mm to 10mm, the adjustment range of the pull rate or the ending temperature corresponding to the time is 1% to 10% each time, and the allowable deviation ratio threshold η is set for each adjustment₀Can be smaller, e.g., 0 ≦ η₀≤0.05。

In another embodiment, a method for ending a single crystal furnace is used for controlling the tail length of a silicon single crystal rod, and comprises the following steps:

according to the preset ending parameters, carrying out first ending, adjusting the preset ending parameters according to the method for controlling the length of the tail part of the monocrystalline silicon, and after ending, obtaining first adjusting parameters to obtain a first monocrystalline silicon rod;

judging whether the tail length of the first monocrystalline silicon rod meets the requirement, if so, taking the first adjustment parameter as a final parameter, and putting into production; if not, the following method is executed:

performing Nth ending according to the (N-1) th adjusting parameter, adjusting the (N-1) th adjusting parameter according to the method for controlling the length of the tail part of the monocrystalline silicon, and obtaining the Nth adjusting parameter after ending the ending to obtain an Nth monocrystalline silicon rod, wherein N is an integer more than or equal to 2;

and judging whether the tail length of the Nth monocrystalline silicon rod meets the requirement, and if so, taking the Nth adjustment parameter as a final parameter to put into production.

It should be noted that, generally, in the case of manual adjustment, the tail length and the expected tail length L can be obtained by 3-5 times of adjustment₀A similar single crystal silicon rod. If the tail length L is adjusted by matching with a computer software program, the tail length and the expected tail length L can be obtained by adjusting 2-3₀A silicon single crystal rod which is close and has a tail part with a relatively regular conical shape.

By adopting the ending method of the single crystal furnace, the tail length of the single crystal silicon rods of the same batch or similar batches can be controlled, and the problems that the tail of the single crystal silicon rod is too long, the ending materials are more, the ending time is long, or the tail of the single crystal silicon rod is too short, dislocation is caused, and the crystal loses a complete single crystal structure are avoided. Meanwhile, the tail length of the monocrystalline silicon rod is controlled, and reliable ending control parameters can be provided for batch secondary production of monocrystalline silicon rods with special requirements. Moreover, the ending parameters of the single crystal furnace obtained by the method, particularly the ending parameters of the single crystal furnace obtained under the condition of auxiliary adjustment of computer software, are a continuous function taking the pulling speed of crystal pulling and the ending temperature as variables in the expression form, and compared with the traditional periodic ending parameters, the ending process is more stable and controllable, the tail shape of the silicon single crystal rod is more regular, and the ending success rate is higher.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.