Novel guiding and releasing method

Abstract

The invention relates to the technical field of monocrystalline silicon manufacturing, in particular to a novel drawing and releasing method which comprises the following steps: controlling the growth of a silicon single crystal by adopting a czochralski method; introducing a seed crystal with a specific crystal orientation into the melt; after material melting is completed, the power of a heater is set as seeding power, and the temperature in the furnace is kept constant; seed crystals make contact with the solid-liquid phase connecting surface, and during seeding, the temperature is dynamically regulated and controlled to be kept within a constant range. According to the invention, the process of manually judging whether seeding succeeds or not, judging the stability of crystal pulling and manually controlling temperature adjustment is cancelled; after material melting is completed, the temperature in the furnace is controlled and kept constant, the shouldering step is directly carried out, the temperature change interval is set in the shouldering process, the shouldering radial line detection is carried out, the cooling amplitude is automatically adjusted, and the temperature in the shouldering process is ensured to be appropriate until shouldering is successful, so that the temperature adjustment and seeding steps can be skipped, a large amount of working hours are saved, and the production efficiency is improved. According to the invention, 10% of workload can be reduced in an ideal state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single crystal silicon manufacturing, in particular to a novel pulling-off method. BACKGROUND

[0002] The Czochralski method is the main method for preparing single crystals at present, and from the early invention to now, the method of eliminating dislocations by necking in the seed crystal stage has been used to form a dislocation-free crystal growth process method, making large-size single crystal growth possible and being put into industrial production.

[0003] The core of the existing crystal pulling process in the early stage is seed crystal fusion, temperature adjustment and seed crystal pulling, among which the seed crystal serves as a crystal growth template to ensure that the newly grown crystal is consistent with the crystal direction of the seed crystal; the temperature adjustment and fusion process is to avoid crystal defects such as dislocations and twins during crystal growth, and finally a single crystal with no defects, high purity and large size is obtained through precise temperature control, pulling speed and thermal field design.

[0004] After the feeding is completed, the molten material is waited, the temperature of the molten material is controlled to the liquid temperature required for fusion, the fusion is performed after the liquid temperature reaches the target liquid temperature, the seed crystal is pulled after the fusion is completed, and the shoulder is then pulled. The preparation process in the middle takes a lot of time and affects the production efficiency. In the temperature adjustment and pulling-off process, the main difficulties are: 1. Stability of the thermal field: small fluctuations in the temperature gradient will cause crystal defects; 2. Stability of the solid-liquid interface: polycrystalline growth caused by supercooling or overheating needs to be avoided; and the temperature needs to be stable during the isodiametric growth period, and temperature surges are inevitable during temperature control.

[0005] Therefore, it is necessary to invent a novel pulling-off method to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide a novel pulling-off method, which solves the problem that the traditional solidification felt is easy to be powdered during the high-temperature operation of the single crystal furnace, resulting in reduced heat preservation performance, increased energy consumption of the single crystal furnace and reduced yield.

[0007] To achieve this purpose, the present application adopts the following technical solutions: A novel pulling-off method is provided, which comprises the following steps: Step S1: controlling the growth of silicon single crystals by the Czochralski method; Step S2: introducing a seed crystal with a specific crystal direction into the melt; Step S3: after the molten material is completed, setting the power of the heater to the crystal pulling power and keeping the temperature in the furnace constant; Step S4: the seed crystal contacts the solid-liquid phase interface, and the temperature is dynamically adjusted during the crystal pulling to keep it within a constant range; Step S5: performing the shoulder pulling step, controlling the shoulder pulling speed of the crystal, and controlling the shoulder temperature; Step S6: control the temperature variation range in the shoulder process and perform the shoulder diameter detection; Step S7: automatically adjust the cooling amplitude to ensure that the temperature in the shoulder process is appropriate until the shoulder process is successful.

[0008] As a preferred scheme of the new type of seeding method, the heater power and the seeding power in step S3 are 55-65 kw.

[0009] As a preferred scheme of the new type of seeding method, the shoulder pulling speed in step S5 is 65-85 mm / h, and the shoulder temperature is controlled by the shoulder interval power.

[0010] As a preferred scheme of the new type of seeding method, when the crystal length in the shoulder process is less than 50, the power in the shoulder interval is 1.5-3 kw / h.

[0011] As a preferred scheme of the new type of seeding method, when the crystal length in the shoulder process is 50-150, the power in the shoulder interval is 3-5 kw / h.

[0012] As a preferred scheme of the new type of seeding method, when the crystal length in the shoulder process is 150-300, the power in the shoulder interval is 6-8 kw / h.

[0013] As a preferred scheme of the new type of seeding method, the constant temperature in step S4 is 1450 DEG C.

[0014] As a preferred scheme of the new type of seeding method, the temperature variation range in step S6 is 40-60 DEG C.

[0015] As a preferred scheme of the new type of seeding method, the shoulder diameter detection in step S6, when the diameter detection value is less than 4, the system determines that it is abnormal, and the abnormality lasts for 20 minutes, and the device defaults to break the line.

[0016] The beneficial effects of the present application are as follows: the present application cancels the manual judgment of the success of the seeding and the stability of the crystal pulling and the process of manually controlling the temperature adjustment; after the melting material is completed, the temperature in the furnace is controlled and kept constant, the shoulder process is directly performed, the temperature variation range in the shoulder process is set, the shoulder diameter detection is performed, the cooling amplitude is automatically adjusted to ensure that the temperature in the shoulder process is appropriate until the shoulder process is successful, thus the temperature adjustment and the seeding process can be skipped, a large amount of working hours can be saved, and the present application can reduce 10% of the workload under the ideal state. DETAILED DESCRIPTION

[0017] The technical scheme of the present application will be further described through the specific embodiments.

[0018] In the description of the present application, unless otherwise explicitly specified and limited, if the term "connection" and the like appear to indicate the connection relationship between components, the term should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0019] The present application provides a new method for introducing a fire, comprising the following steps: Step S1: using the Czochralski method to control the growth of silicon single crystal; Step S2: introducing a seed crystal with a specific crystal direction into the melt; Step S3: after the completion of the melt, the heater power is set to the crystal introduction power, and the temperature in the furnace is kept constant; Step S4: the seed crystal contacts the solid-liquid phase interface, and when the crystal is introduced, the temperature is dynamically controlled to keep it within a constant range.

[0020] Step S5: perform the shoulder step, control the shoulder pulling speed of the crystal, and control the shoulder temperature; Step S6: control the temperature variation range during the shoulder process and perform the shoulder diameter detection; Step S7: automatically adjust the cooling amplitude to ensure that the temperature during the shoulder process is appropriate until the shoulder process is successful.

[0021] The heater power and the crystal introduction power in step S3 are 55-65kw.

[0022] The shoulder pulling speed in step S5 is 65-85mm / h, and the shoulder temperature is controlled by the shoulder interval power.

[0023] When the length of the shoulder crystal is less than 50, the power of the shoulder interval is 1.5-3kw / h.

[0024] When the length of the shoulder crystal is 50-150, the power of the shoulder interval is 3-5kw / h.

[0025] When the length of the shoulder crystal is 150-300, the power of the shoulder interval is 6-8kw / h.

[0026] The constant temperature in step S4 is 1450℃.

[0027] The temperature variation range in step S6 is 40-60℃.

[0028] The shoulder diameter line detection in the step S6, when the diameter line detection value is less than 4, the system determines the abnormality, the abnormality lasts for 20 minutes, and the device defaults the broken line.

[0029] In the process of shoulder, the crystal blocks the temperature measuring point, and cannot accurately identify the temperature, so the shoulder power is adjusted to control the shoulder temperature.

[0030] The temperature regulation mode of the seed crystal includes: only one continuous diameter reduction process in the whole process of introducing the seed crystal, the temperature regulation amount of the seed crystal is set according to the power adjustment coefficient in the whole process; or the process of introducing the seed crystal is a non-continuous diameter reduction process, including a first diameter reduction process, an equal crystal process and a second diameter reduction process, the target diameter of the second diameter reduction process is reached, the temperature regulation of the seed crystal is carried out in the equal crystal process, the temperature regulation amount of the seed crystal is set according to the power adjustment, and the deviation of the seed crystal power will cause the success or failure of the seed crystal, so the seed crystal pulling speed at the time of the end of the seed crystal or the failure of the seed crystal is observed to judge, which greatly increases the existing workload.

[0031] The patent shortens the preparation work by saving the welding and seed crystal time, and further improves the single crystal production efficiency; the Czochralski method is a controlled solid-liquid transformation process, in which, under certain conditions, the atoms at the solid-liquid interface are continuously transformed from liquid to solid, so that the solid crystal gradually becomes larger, and the desired size requirement is reached. The main sign that distinguishes the crystalline solid silicon from the molten silicon is that the interatomic binding force restricts the equilibrium position of the atoms, making the crystal a rigid solid. To make the crystalline solid into a melt, external energy is needed to weaken this binding force, so that the atoms are randomly distributed away from the lattice position. In actual production, the method of heating is usually used to realize the transformation from solid to liquid, at this time the heat required is called the latent heat of fusion, and the transformation point temperature is the melting point of the substance. When the melt solidifies, the free energy of the system decreases, and the transformation from liquid to solid is completed by releasing this part of energy. Therefore, heat is the fundamental driving force to realize the above-mentioned transformation; therefore, after the melting material is completed, the initial temperature in the furnace is stable without large temperature fluctuations, at this time the heater power is set to the seed crystal power, the temperature in the furnace is kept stable, the seed crystal contacts the liquid surface, the contact position will be cooled rapidly to form a crystallization surface, the seed crystal temperature is kept at 1450℃ during the seed crystal time, after the seed crystal contacts the liquid surface, the melting process is done by heating, such as using the seed crystal that has completed the melting and seed crystal, the seed crystal is used in the solid-liquid interface, and the crystallization surface is enlarged to the ideal size by controlling the pulling speed and the shoulder temperature, the process is the shoulder step, so the temperature adjustment and seed crystal steps can be skipped, and a lot of working hours can be saved.

[0032] In the embodiment, a normal end seed crystal is found, a fine crystal is left and the length of the fine crystal is ensured to be 100-200 mm, the liquid surface temperature is stabilized to be greater than 1450 DEG C while the seed crystal is lowered, the temperature of the seed crystal when contacting the liquid surface is not lower than 1450 DEG C, the power of the crystal is matched with the liquid temperature, the liquid temperature is ensured to be greater than 1450 DEG C, the state of the seed crystal is observed after the seed crystal contacts the solid-liquid surface, the crystal pulling speed is set to be 60-80 mm / h when the crystal point appears, and the automatic shoulder placing is executed according to the shoulder placing working step and parameters.

[0033] The present application cancels the manual judgment of the success of the crystal pulling and the stability of the crystal pulling and the process of manually controlling the temperature adjustment, controls and keeps the temperature in the furnace constant after the melting material is completed, directly carries out the shoulder placing working step, sets the temperature change range and the shoulder diameter line detection in the shoulder placing process, automatically adjusts the cooling amplitude, ensures that the temperature in the shoulder placing process is appropriate, and until the shoulder placing is successful, so that the temperature adjustment and the crystal pulling working step can be skipped, a large amount of working hours can be saved, and the present application can reduce 10% of the workload in the ideal state.

[0034] It should be noted that the above specific embodiments are only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art should understand that various modifications, equivalent replacements, changes and the like can be made to the present application. However, as long as these changes do not deviate from the spirit of the present application, they should be within the protection scope of the present application. In addition, some terms used in the present application specification and claims are not limited, but only for convenient description.

Claims

1. A novel method of arc extinguishing, characterized in that, The method comprises the following steps: Step S1: controlling the growth of silicon single crystal by using the Czochralski method; Step S2: introducing a seed crystal with a specific crystal orientation into the melt; Step S3: after the completion of the melting, setting the heater power as the seeding power and keeping the temperature in the furnace constant; Step S4: when the seed crystal contacts the solid-liquid interface, dynamically adjusting the temperature so as to keep it within a constant range during the seeding; Step S5: performing the shoulder growth step, controlling the shoulder growth speed of the crystal and controlling the shoulder growth temperature; Step S6: controlling the temperature variation range during the shoulder growth and performing the shoulder diameter detection; Step S7: automatically adjusting the temperature reduction range to ensure that the temperature during the shoulder growth is appropriate until the shoulder growth is successful.

2. A novel method of extinguishing a fire as claimed in claim 1, wherein: The heater power in the step S3 is 55-65 kw.

3. A novel method of extinguishing a fire as claimed in claim 1, wherein: The shoulder growth speed in the step S5 is 65-85 mm / h, and the shoulder growth temperature is controlled by the shoulder growth range power.

4. A novel method of extinguishing a fire as claimed in claim 3 wherein: When the length of the crystal during the shoulder growth is less than 50, the power of the shoulder growth range is 1.5-3 kw / h.

5. A novel method of extinguishing a fire as claimed in claim 4 wherein: When the length of the crystal during the shoulder growth is 50-150, the power of the shoulder growth range is 3-5 kw / h.

6. A novel method of extinguishing a fire as claimed in claim 5 wherein: When the length of the crystal during the shoulder growth is 150-300, the power of the shoulder growth range is 6-8 kw / h.

7. A novel method of extinguishing a fire as claimed in claim 6 wherein: The constant temperature in the step S4 is 1450℃.

8. A novel method of extinguishing a fire as claimed in claim 1, wherein: The temperature variation range in the step S6 is 40-60℃.

9. A novel method of extinguishing a fire as claimed in claim 5 wherein: In the shoulder diameter detection in the step S6, when the diameter detection value is less than 4, the system determines that an abnormality occurs, and the abnormality lasts for 20 minutes, and the device is defaulted to be disconnected.