Method for determining seeding power

Abstract

The invention belongs to the technical field of single crystal production, and relates to a method for determining seeding power, which comprises the following steps: recording melting starting time h1, recording melting ending time h2 when a solid-to-liquid ratio reaches a preset value, and obtaining actual melting time H (H = h2-h1); recording the initial crucible material weight a and the actual melting time H, and calculating the melting rate v, wherein v is equal to a / H; calculating a non-first furnace power compensation value Kb according to the melting rate V; and calculating non-first furnace seeding power K according to the first furnace seeding power Ka and the non-first furnace power compensation value Kb, wherein K = Ka + Kb. The method has the beneficial effects that the melt finishing signal is accurately collected through the change of the solid-to-liquid ratio, and the non-first furnace seeding power is calculated through the melt rate, so that the accuracy of the initial seeding power is improved, the initial first shoulder expansion survival rate, the one-time crystallization rate and the whole rod rate can be increased, and the production cost is reduced. And the seeding power recommended on the basis of the thermal field thermal insulation performance condition is combined with the SOP parameters, so that the equal-diameter pulling speed can be better matched, and the pulling speed scattering difference is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of single crystal production and relates to a method for determining crystal seeding power. Background Art

[0002] The thermal system of a CZ single crystal furnace consists of a heater, a heat preservation system, a support mechanism, a support rod, a support bowl (graphite crucible), etc. The heater is the main body of the thermal system and is made of high-purity graphite. Most heat preservation systems are made of high-purity graphite and carbon felt, and some are made of a mixture of carbon-carbon composite materials, carbon felt, cured felt, high-purity quartz, molybdenum sheets and high-purity graphite. The size, height, thickness of the thermal system are different, and the temperature changes differently. The temperature gradient is used to quantitatively describe the temperature distribution. The so-called temperature gradient refers to the rate of change of temperature in a certain direction, and dr / dT is used to represent the rate of change of temperature T at a certain point in the r / ρ direction. Within a certain distance, the greater the temperature difference in a certain direction, the greater the temperature change per unit distance, and the greater the temperature gradient; conversely, the smaller the temperature difference, the smaller the temperature gradient. So we imitate the force field in thermodynamics and the magnetic field description in electricity, and call this thermodynamic temperature distribution "temperature field", usually called "thermal field".

[0003] The thermal field is mainly affected by the thermal system, and the thermal field will definitely change when the thermal system changes. The thermal field of the single crystal furnace is constantly changing during the entire crystal pulling process. Taking the static thermal field as an example, after the polysilicon melts, the temperature distribution during seeding is determined by the heater, insulation system, crucible position and surrounding environment. When the single crystal furnace stops running and is restarted, the position of the carbon felt in the insulation system will change, and the service life of the thermal field of each furnace is different. The above differences will directly lead to changes in the thermal insulation of the static thermal field, which will directly affect the seeding power search of each furnace, affecting the initial crystallization rate and the whole rod pulling speed. Therefore, a method for determining the seeding power is needed to solve the above technical problems. Summary of the invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a method for determining the seeding power, which can avoid the difficulty in finding the initial seeding power caused by the change of thermal field due to dismantling and the difference in thermal field life, and the actual cooling after entering the equal diameter does not meet the actual needs, resulting in the dispersion of the pulling speed out of the furnace.

[0005] The technical solution adopted by the present invention is: a method for determining seeding power, characterized in that it comprises the following steps:

[0006] Record the melting start time h1, and when the solid-liquid ratio reaches the preset value, record the melting end time h2, and obtain the actual melting time H, H = h2-h1;

[0007] Record the initial charging weight a and the actual melting time H to calculate the melting rate v, v = a / H;

[0008] Calculate the non-first furnace power compensation value Kb according to the melt rate V;

[0009] The non-first furnace seeding power K is calculated according to the first furnace seeding power Ka and the non-first furnace power compensation value Kb, where K=Ka+Kb.

[0010] Furthermore, when the preset value is 0.03-0.1, the melting ends.

[0011] Furthermore, the non-first furnace power compensation value Kb is obtained according to the compensation value b corresponding to the melt rate v and the fixed compensation power c, that is, Kb=b×c.

[0012] Furthermore, when the melt rate v>90kg / h, the compensation value b is -0.9~-1.1.

[0013] Furthermore, when the melt rate is 60<v≤90kg / h, the compensation value b is -1.1 to -0.3.

[0014] Furthermore, when the melt rate is 50≤v≤60kg / h, the compensation value b is 0.

[0015] Furthermore, when the melt rate is 20≤v<50kg / h, the compensation value b is 0.3-0.9.

[0016] Furthermore, when the melt rate is v<20 kg / h, the compensation value b is 0.9-1.1.

[0017] Furthermore, the fixed compensation power c is 1.4-1.6.

[0018] Furthermore, the fixed compensation power c is 1.5.

[0019] The present invention relates to a tail-end single crystal crystallization method, in which a melt end signal is accurately collected through a change in a solid-liquid ratio, and then a non-first furnace seeding power is calculated through a melt rate under conditions of equal melt power, thereby improving the accuracy of the initial seeding power. The seeding power accuracy is improved, and the initial first shoulder expansion survival rate, one-time crystallization rate, and whole rod rate can be increased. Moreover, the seeding power recommended based on the thermal field insulation performance conditions combined with the SOP parameters can better match the equal-diameter pulling speed and reduce the pulling speed dispersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of an embodiment provided by the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Figure 1As shown, this process flow mainly includes temperature stabilization, seeding, shoulder release and equal diameter processes.

[0022] The present invention provides a method for determining seeding power, characterized in that it comprises the following steps:

[0023] Record the melting start time h1, and when the solid-liquid ratio reaches the preset value, record the melting end time h2, and obtain the actual melting time H, H = h2-h1;

[0024] Record the initial charge weight a and the actual melting time H to calculate the melting rate v, v = a / H;

[0025] Calculate the non-first furnace power compensation value Kb according to the melt rate V;

[0026] The non-first furnace seeding power K is calculated based on the first furnace seeding power Ka and the non-first furnace power compensation value Kb, K = Ka + Kb. With the increasing number of times the single crystal furnace is used, the melting time under the same heater power condition is also constantly changing, which will directly affect the search for seeding power for each furnace, affecting the initial crystallization rate and the whole rod pulling speed. This technical solution accurately collects the actual melting time through the change of the solid-liquid ratio, and calculates the actual melting rate to calculate the non-first furnace seeding power, thereby improving the accuracy of the initial seeding power. The improvement of the seeding power accuracy can increase the initial first shoulder expansion survival rate, the one-time crystallization rate, and the whole rod rate, and the seeding power recommended based on the thermal field insulation performance conditions combined with the SOP parameters can better match the equal diameter pulling speed and reduce the pulling speed dispersion.

[0027] Preferably, when the preset value is 0.03-0.1, the melting ends.

[0028] Preferably, the non-first furnace power compensation value Kb is obtained according to the compensation value b corresponding to the melt rate v and the fixed compensation power c, that is, Kb=b×c.

[0029] Preferably, when the melt rate v>90kg / h, the compensation value b is -0.9 to -1.1.

[0030] Preferably, when the melt rate is 60<v≤90kg / h, the compensation value is -1.1 to -0.3.

[0031] Preferably, when the melt rate is 50≤v≤60kg / h, the compensation value b is 0.

[0032] Preferably, when the melt rate is 20≤v<50kg / h, the compensation value b is 0.3-0.9.

[0033] Preferably, when the melt rate is v<20 kg / h, the compensation value b is 0.9-1.1.

[0034] Preferably, the fixed compensation power c is 1.4-1.6.

[0035] Preferably, the fixed compensation power c is 1.5.

[0036] When in use, the PLC system collects the melting start signal time, records the melting start time h1, and the CCD visual inspection system collects the melting end time h2, calculates the actual melting time H, and then calculates the actual melting rate v. The non-first furnace power compensation value Kb is obtained according to the compensation value b and the fixed compensation power c corresponding to the actual melting rate v. The non-first furnace seeding power K is calculated according to the first furnace seeding power Ka and the non-first furnace power compensation value Kb, which is the recommended seeding power. A more accurate melting end time can accurately calculate the melting rate, which not only improves the accuracy of the initial seeding power, but also increases the survival rate of the first shoulder expansion by 3%.

[0037] The present invention relates to a tail-end single crystal crystallization method, in which a melt end signal is accurately collected through a change in a solid-liquid ratio, and then a non-first furnace seeding power is calculated through a melt rate under conditions of equal melt power, thereby improving the accuracy of the initial seeding power. The seeding power accuracy is improved, and the initial first shoulder expansion survival rate, one-time crystallization rate, and whole rod rate can be increased. Moreover, the seeding power recommended based on the thermal field insulation performance conditions combined with the SOP parameters can better match the equal-diameter pulling speed and reduce the pulling speed dispersion.

[0038] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for determining seeding power, characterized in that: The steps include: Record the melting start time h1, and when the solid-liquid ratio reaches the preset value, record the melting end time h2, and obtain the actual melting time H, H = h2-h1; Record the initial charging weight a and the actual melting time H to calculate the melting rate v, v = a / H; Calculate the non-first furnace power compensation value Kb according to the melt rate V; The non-first furnace seeding power K is calculated according to the first furnace seeding power Ka and the non-first furnace power compensation value Kb, where K=Ka+Kb.

2. The method for determining seeding power according to claim 1, characterized in that: When the preset value is 0.03-0.1, the melting is finished.

3. The method for determining seeding power according to claim 2, characterized in that: The non-first furnace power compensation value Kb is obtained according to the compensation value b corresponding to the melt rate v and the fixed compensation power c, that is, Kb=b×c.

4. The method for determining seeding power according to claim 3, characterized in that: When the melt rate v>90kg / h, the compensation value b is -0.9 to -1.

1.

5. The method for determining seeding power according to claim 4, characterized in that: When the melt rate is 60<v≤90kg / h, the compensation value b is -1.1 to -0.

3.

6. The method for determining seeding power according to claim 5, characterized in that: When the melt rate is 50≤v≤60kg / h, the compensation value b is 0.

7. The method for determining seeding power according to claim 6, characterized in that: When the melt rate is 20≤v<50kg / h, the compensation value b is 0.3-0.

9.

8. The method for determining seeding power according to claim 7, characterized in that: When the melt rate is v<20kg / h, the compensation value b is 0.9-1.

1.

9. The method for determining seeding power according to any one of claims 3 to 8, characterized in that: The fixed compensation power c is 1.4-1.

6.

10. The method for determining seeding power according to claim 9, characterized in that: The fixed compensation power c is 1.5.

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