Laser heating device and method for accurately controlling temperature of silicon material melting zone and diameter of silicon core

Abstract

The invention discloses a laser heating device for accurately controlling the temperature of a silicon material melting zone and the diameter of a silicon core, which comprises a furnace chamber, and an induction heating coil is arranged in the furnace chamber and is used for integrally heating a master batch rod; a plurality of lasers are arranged outside the furnace chamber and are used for preheating a master batch rod, or heating the master batch rod in different areas, or heating the bottom of a drawn silicon core; a plurality of light-transmitting openings are evenly formed in the side wall of the furnace chamber, and laser beams emitted by the laser irradiate into the furnace chamber through the light-transmitting openings so as to heat the master batch bar. The invention also discloses a method for heating the master batch rod by using the laser heating device. According to the method, the temperature of the silicon material melting zone can be accurately controlled, and silicon core diameter deviation caused by non-uniform induction heating is eliminated.

Description

Technical Field

[0001] The present invention belongs to the field of zone melting silicon core growth process and its control technology, and specifically relates to a laser heating device for accurately controlling the silicon material melting zone temperature and silicon core diameter. The present invention also relates to a method for heating a silicon core masterbatch rod using the above laser heating device. Background Art

[0002] The silicon core is a long and thin silicon rod. It plays a vital role as the substrate for silicon material deposition in the polycrystalline reduction furnace. It is the starting point for the reduction and deposition of silicon materials and provides a deposition site for silicon atoms on its surface. The preparation of silicon core mainly adopts two process methods: zone melting and mechanical processing. Among them, the zone melting method is mainly used to draw round silicon cores. It can be easily doped in gaseous state and is the core method in the preparation process of semiconductor-grade high-quality polycrystalline silicon.

[0003] Problems with existing technologies: When the zone melting method is used to draw silicon cores, a high-frequency induction coil is traditionally used to heat the silicon masterbatch rod, so that a molten zone is generated on the upper part, and then the seed crystal is welded, and then a slender silicon core product is grown upward by pulling the seed crystal. Since silicon at room temperature does not have conductive properties and cannot be heated by an induction coil, auxiliary means are required to preheat the silicon to a temperature close to the melting point to make it a conductor, so that induction heating can be used to further absorb heat and heat it to become a melt. Commonly used silicon material preheating methods include molybdenum wire heating method, graphite disc heating method, graphite fork sleeve quartz tube and low-resistance silicon heating method. The basic principle of the above preheating method is to use induction heating to heat conductive intermediate materials such as molybdenum wire, graphite and low-resistance silicon, so that they are heated up and then preheat the silicon raw material by heat conduction. These heterogeneous materials used as intermediates are prone to produce impurities at high temperatures and contaminate the raw material rods. It is difficult to meet the cleanliness requirements in the production of high-purity semiconductor silicon materials. Therefore, quartz sleeves are needed for isolation and protection. However, due to the poor thermal conductivity of quartz tubes, the chemical process will be slow and energy consumption will be high.

[0004] In order to improve production efficiency, the current method of simultaneously drawing multiple silicon cores with one masterbatch rod is usually used in the production process of zone melting silicon core. The growth rate and diameter of the silicon core are affected by the temperature of the silicon melt. If the temperature is too high, the silicon core is not supercooled enough and the condensation amount decreases; if the temperature is too low, the condensation amount increases and the growth rate accelerates. When multiple silicon cores are pulled upward at the same speed, the condensation amount is small and the diameter is thinner when the temperature is high; the condensation amount is large and the diameter is thicker when the temperature is low. In order to meet the diameter deviation requirements of the silicon core, it is necessary to finely design the current path of different growth areas on the induction heating coil so that the power, temperature and crystal diameter of different silicon core growth areas on the same heating coil are as consistent as possible. However, there are inevitably machining errors and state differences during growth, and it is difficult to ensure that the diameter of the silicon core is exactly the same. Taking the usual 5 8mm diameter silicon core growth system as an example, there is usually a deviation of ±1mm between each silicon core, which is equivalent to a maximum error of 25%, which cannot meet the diameter deviation requirements of high-quality silicon cores.

[0005] In order to keep the heating power of different silicon core growth areas on the same heating coil consistent, it is necessary to process many fine grooves on the heating coil and adjust the thickness of different areas, so as to adjust the current flow and on-resistance to achieve the purpose of uniform heating power. However, the processing of these grooves and different thickness areas makes there are many fine cracks and sharp corners on the heating coil. When the voltage and current of the high-frequency induction power supply are large, local discharge and arc are easily generated, which will affect the heating of the coil and burn and damage the induction coil. When process gases such as phosphine are added during the growth of semiconductor-grade silicon cores, the discharge phenomenon is more serious, which becomes an important obstacle to further improving the quality of silicon cores. Summary of the invention

[0006] The purpose of the present invention is to provide a laser heating device for accurately controlling the temperature of a silicon material melting zone and the diameter of a silicon core.

[0007] Another object of the present invention is to provide a method for heating a silicon core masterbatch rod using the above-mentioned laser heating device, which can accurately control the temperature of the silicon material melting zone and eliminate the silicon core diameter deviation caused by uneven induction heating.

[0008] The technical solution adopted by the present invention is a laser heating device for accurately controlling the temperature of the silicon material melting zone and the diameter of the silicon core, comprising a furnace chamber, wherein an induction heating coil is arranged inside the furnace chamber for heating the master material rod as a whole; a plurality of lasers are arranged outside the furnace chamber, and the lasers are used to preheat the master material rod, or to heat the master material rod in different areas, or to heat the bottom of the drawn silicon core; a plurality of light-transmitting openings are evenly arranged on the side wall of the furnace chamber, and the laser beam emitted by the laser is irradiated into the furnace chamber through the light-transmitting opening, thereby heating the master material rod.

[0009] The present invention is also characterized in that: The laser emits a laser beam in a straight line laser output mode with a certain opening angle.

[0010] The laser is a fiber-optic transmission laser, which includes a laser generator, and the laser generator is connected to a laser lens via a transmission optical fiber.

[0011] The laser is a vertical cavity surface emitting laser with a planar array output characteristic, and the number of lasers arranged in the same area to be heated of the masterbatch rod is one or more.

[0012] An adjustment mechanism is arranged below the laser, and the adjustment mechanism is used to adjust the height of the laser and the distance between the laser and the furnace chamber.

[0013] The adjustment mechanism comprises a base, a slide rail is arranged on the surface of the base, a sliding block used in conjunction with the sliding rail is sleeved on the sliding rail, and the sliding block is fixed under the laser.

[0014] Another technical solution adopted by the present invention is a laser heating method for accurately controlling the temperature of the silicon material melting zone and the diameter of the silicon core. Using the above-mentioned laser heating device, during the silicon core drawing process, a plurality of evenly distributed lasers are used to preheat the masterbatch rod. After the silicon material at the top of the masterbatch rod heats up and becomes conductive, an induction heating coil is used to heat the masterbatch rod as a whole. After a melting zone is formed at the top of the masterbatch rod, a plurality of lasers are used simultaneously to heat the melting zone in sections, thereby accurately controlling the diameter of the silicon core formed by each melting zone.

[0015] Another technical solution of the present invention is also characterized in that: Multiple lasers emit laser beams to irradiate the masterbatch rod, and the irradiation range of the multiple laser beams covers 360 degrees around the masterbatch rod.

[0016] The beneficial effects of the present invention are: Compared with the preheating method of the traditional silicon core furnace, the device of the present invention adopts laser preheating, which can prevent the risk of impurity contamination caused by the traditional preheating methods such as graphite rings; compared with the silicon core growth system that uses the induction heating coil alone, the method of the present invention can control the power of the laser projected at different angles, and finely control the temperature of the lower melting zone of the silicon core in different regions, thereby realizing the separate control of the diameters of multiple silicon cores and eliminating the deviation of the silicon core diameter caused by uneven induction heating. In addition, after adopting laser composite heating, the voltage and current applied to the induction heating coil are reduced, and the heating power of the coil is reduced, so it is not easy to generate arcs in the gaps and sharp corners of the coil, which can effectively prevent the coil from igniting and arcing, and improve the overall heating efficiency.

[0017] The method of the present invention adopts an induction coil and multiple lasers to jointly heat the silicon core masterbatch rod, thereby solving many problems affecting the quality of the silicon core, such as preheating of silicon material, precise control of silicon core diameter, and reducing power of the induction coil to prevent arcing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the laser heating device of the present invention; Figure 2 is a top view of the laser heating device of the present invention; Figure 3 is a schematic diagram of the laser beam acting on the masterbatch rod in the method of the present invention; Figure 4 It is a schematic diagram of the structure of the optical fiber guided laser in the device of the present invention; Figure 5 is a schematic diagram of superimposed irradiation using a vertical cavity surface emitting laser in the method of the present invention; Figure 6 It is a schematic diagram of using a laser to heat the root of a silicon core in the method of the present invention.

[0019] In the figure, 1. masterbatch rod, 101. melting zone, 2. induction heating coil, 201. positive pole of coil, 202. negative pole of coil, 203. grounding of coil, 3. silicon core, 4. laser, 401. laser beam, 402. laser lens, 403. transmission optical fiber, 404. laser generator, 5. furnace chamber, 501. light transmission port, 6. adjustment mechanism. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The laser heating device of the present invention can accurately control the temperature of the silicon material melting zone and the diameter of the silicon core, and the structure is as follows: Figure 1 and Figure 2 As shown, it includes a furnace chamber 5, wherein an induction heating coil 2 is arranged inside the furnace chamber 5 for heating the masterbatch rod 1 as a whole; a plurality of lasers 4 are arranged outside the furnace chamber 5 for preheating the masterbatch rod 1 and heating the masterbatch rod 1 in sections; a plurality of light-transmitting openings 501 are evenly opened on the side wall of the furnace chamber 5, and a laser beam 401 emitted by the laser 4 is irradiated into the furnace chamber 5 through the light-transmitting opening 501, thereby heating the masterbatch rod 1.

[0022] like Figure 2 As shown, the laser 4 uses a straight line laser output mode with a certain angle to emit a laser beam 401, each laser 4 covers a certain arc length of the masterbatch rod 1, and multiple lasers 4 project laser beams 401 from different angles to achieve full coverage of 360 degrees of the masterbatch rod 1. The method of the present invention can also use a point laser for heating, but the laser energy is concentrated at one point, and the heating is uneven, which is a degraded implementation method.

[0023] An adjustment mechanism 6 is provided below the laser 4 for adjusting the height of the laser 4 and the distance between the laser 4 and the furnace chamber 5. The adjustment of the distance between the laser 4 and the furnace chamber 5 can be achieved through the following structure: the adjustment mechanism 6 includes a base, a slide rail is provided on the surface of the base, a slider used in conjunction with the slide rail is provided below the laser 4, and the slider slides along the slide rail, so that the laser 4 can adjust the front and rear position along the laser emission direction. Adjusting the front and rear position of the laser 4 can control the length of the arc covered by the straight line laser beam on the masterbatch rod 1, thereby adjusting the heating area of ​​a single laser 4. The height position of the laser 4 can be adjusted by providing a retractable sleeve structure below the base.

[0024] like Figure 1-Figure 3 As shown, when the device of the present invention is in use, the masterbatch rod 1 is placed below the induction heating coil 2 in the furnace chamber 5, the induction heating coil 2 and the laser 4 heat the masterbatch rod 1, and a molten zone 101 is formed on the top of the masterbatch rod 1, and then a silicon core 3 is grown from the molten zone 101 by pulling the seed crystal.

[0025] By applying a high-frequency power supply between the positive pole 201 and the negative pole 202 of the induction heating coil 2, a high-frequency induced eddy current is formed on the master material rod 1 to achieve overall heating of the silicon raw material. The laser 4 is installed outside the furnace chamber 5, and the laser beam 401 is projected onto the master material rod 1 at the bottom of the specific silicon core 3 corresponding to the laser 4 through multiple light-transmitting ports 501 on the furnace chamber 5 to achieve zoned heating. The power of the induction heating coil 2 affects the temperature of the lower melting zone of all silicon cores 3, and by adjusting the power of different lasers 4 respectively, the zoned heating of the melting zone 101 is achieved, and the temperature of the lower melting zone of the silicon core 3 corresponding to the laser 4 is finely adjusted, thereby achieving accurate diameter control of multiple silicon cores 3 respectively. The number of silicon cores set is related to the diameter of the master material rod and the diameter of the silicon core. The larger the diameter of the master material rod and the smaller the diameter of the silicon core, the more the number of silicon cores that can be set can be increased. The specific number of silicon cores is not the core feature of the device of the present invention.

[0026] In addition, laser heating can also realize preheating of the masterbatch rod 1. After the silicon material at the top of the masterbatch rod 1 heats up and conducts electricity, the induction heating coil 2 performs eddy current induction heating. When preheating the masterbatch rod 1, first turn on multiple lasers 4 to preheat the top area of ​​the masterbatch rod 1 through the laser beam 401. When the temperature of the top area of ​​the masterbatch rod 1 reaches the conductive temperature of silicon, the induction heating coil 2 forms an eddy current at the top of the masterbatch rod 1. The eddy current forms a second heater at the top of the masterbatch rod 1 until a stable melting zone 101 is formed at the top of the masterbatch rod 1, and then the seed crystal is melted and the silicon core is pulled.

[0027] like Figure 4As shown, the laser 4 can be a fiber-optic transmission laser, which includes a laser generator 404, and the laser generator 404 is connected to a laser lens 402 through a transmission optical fiber 403. The laser emitted by the laser generator 404 is transmitted by the transmission optical fiber 403 and projected onto the masterbatch rod 1 through the lens 402 to achieve heating.

[0028] like Figure 5 As shown, the laser 4 may also be a vertical cavity surface emitting laser with a planar array output characteristic. When such a laser is used, a plurality of independent lasers may be arranged at the position of a single silicon core 3 for superimposed irradiation.

[0029] When the laser masterbatch bar preheating function is not required, Figure 6 As shown, the laser 4 can be arranged on the upper part of the induction heating coil 2, and the laser beam 401 emitted by the laser 401 enters the furnace chamber from the light-transmitting port 501, and irradiates the root position of the drawn silicon core 3 close to the induction heating coil 2, thereby increasing the temperature of the specific silicon core 3 and the temperature of the melting zone below the silicon core 3, thereby reducing its growth diameter. In addition, the laser irradiation of the silicon core 3 can be irradiated from one angle or from different angles at the same time to improve the heating uniformity.

[0030] The device of the present invention is provided with an induction heating coil 2 on the upper part of the masterbatch rod 1, and the induction heating coil 2 realizes the overall heating of the masterbatch rod 1 and the melt. A plurality of lasers 4 are installed outside the furnace chamber 5, and the masterbatch rod 1 is heated in different areas through the light-transmitting port 501. Laser heating can realize the preheating of the masterbatch rod 1. After the silicon material at the top of the masterbatch rod 1 heats up and becomes conductive, the induction heating coil 2 performs eddy current induction heating to melt the top of the masterbatch rod 1 and form a molten zone. After the drawing of the silicon core starts, the temperature of the overall growth system is controlled by the power of the induction heating coil 2, and the output power of the plurality of lasers 4 corresponding to the plurality of silicon cores 3 is adjusted respectively, so as to adjust the temperature of the molten zone in a differentiated manner by region, so as to achieve the purpose of finely controlling the diameter of the silicon core 3 in the temperature zone.

[0031] Embodiment 1: This embodiment takes a zone melting silicon core growth system that uses a 100mm diameter masterbatch rod to draw five 8mm diameter silicon cores as an example. Figure 1 and Figure 2 As shown, the silicon core drawing system includes a mother material rod 1, an induction heating coil 2, a silicon core 3 and a laser 4. Figure 3 As shown, 5 silicon cores are evenly distributed on the dividing circle outside the masterbatch rod, 5 silicon core drawing process holes are processed on the induction coil, and a coil positive electrode 201, a coil negative electrode 202 and a coil ground 203 are arranged on the induction coil.

[0032] In the direction opposite to the five silicon cores, five straight-line lasers 4 with a power of 2 kW are arranged. The lasers 4 are installed outside the sealed furnace chamber 5. The laser beams are projected onto the masterbatch rod 1 and the molten zone at the bottom of the specific silicon core 3 through multiple light-transmitting ports 501 on the furnace chamber. The specific maximum power of the laser can be adjusted according to the preheating speed and diameter control requirements.

[0033] The induction heating coil 2 and the laser 4 are used to heat the master material rod 1 and form a molten zone at the top of the master material rod. Then, by pulling the seed crystal to grow, the silicon core 3 grows from the molten zone. The induction heating coil 2 is installed inside the sealed furnace chamber 5. By applying a high-frequency power supply between the coil positive electrode 201 and the coil negative electrode 202, a high-frequency induced eddy current is formed on the master material rod 1 to achieve overall heating of the silicon raw material. The power of the induction heating coil affects the temperature of the lower molten zone of all silicon cores. By adjusting the power of different lasers 4 respectively, the zone heating of the molten zone is achieved, and the temperature of the lower molten zone of different silicon cores 3 is finely adjusted, thereby achieving accurate diameter control of multiple silicon cores respectively.

[0034] The laser 4 of the device of the present invention has the function of preheating the masterbatch rod. When preheating the masterbatch rod, multiple lasers are turned on first to preheat the top area of ​​the masterbatch rod by the laser beam. When the temperature of the top area of ​​the masterbatch rod reaches the conductive temperature of silicon, the induction heating coil forms an eddy current at the top of the masterbatch rod, and the eddy current forms a second heater at the top of the masterbatch rod until a stable melting zone is formed at the top of the masterbatch rod, and then the seed crystal is started to be melted and the silicon core is pulled.

[0035] The laser of this embodiment adopts a straight line laser, and the emitted laser beam has a straight line laser output mode with a certain angle. In this embodiment, the five lasers each cover an arc angle of 72 degrees of the masterbatch rod, and each laser covers an arc length of approximately 63 mm on the surface of the masterbatch rod with a diameter of 100 mm. The five lasers project laser beams from different angles to achieve full coverage of 360 degrees around the masterbatch rod. When the laser is molten, the masterbatch rod is heated with full power output. After a stable molten zone is formed, the laser output power is appropriately reduced. During the growth of the silicon core, the corresponding laser power is adjusted according to the diameter deviation of the silicon core. For silicon cores with larger diameters, the laser output power is increased; for silicon cores with smaller diameters, the laser output power is reduced.

[0036] In order to facilitate the debugging of the system, the laser is installed on an adjustment mechanism, which is fixed on the outer wall of the furnace. The adjustment mechanism can adjust the position of the laser forward and backward along the laser emission direction. The adjustment of the front and rear position of the laser can control the length of the arc covered by the straight-line laser beam on the master rod, thereby adjusting the heating area of ​​a single laser. When the laser position is adjusted toward the silicon core, the arc length projected by a single straight-line laser on the master rod becomes smaller, and the laser energy is relatively concentrated. When the laser position is adjusted in the direction away from the silicon core, the arc length projected by a single straight-line laser on the master rod becomes larger, and the laser energy is relatively dispersed.

[0037] The adjustment mechanism can also increase the pitch angle and rotation angle adjustment functions of the laser, but for a silicon core growth system with a fixed size, these two angles are relatively fixed and do not require frequent adjustments during production. They can be fixed in the appropriate position by a non-adjustable bracket.

[0038] Embodiment 2: This embodiment still takes the zone melting silicon core growth system of using 100mm diameter masterbatch rod to draw 5 8mm diameter silicon cores as an example. Figure 1 and Figure 2 As shown, the silicon core drawing system includes a mother material rod 1, an induction heating coil 2, a silicon core 3 and a laser 4. Figure 3 As shown, 5 silicon cores are evenly distributed on the dividing circle outside the masterbatch rod, 5 silicon core drawing process holes are processed on the induction coil, and a coil positive electrode 201, a coil negative electrode 202 and a coil ground 203 are arranged on the induction coil.

[0039] The difference from Example 1 is that Figure 4 As shown, this embodiment adopts a split laser, and a laser lens 402 is installed on the outside of the furnace wall. The laser lens 402 is connected to the laser generator 404 through a transmission optical fiber 403. The laser emitted by the laser generator 404 is transmitted through the transmission optical fiber 403, and then a straight line laser with a certain angle is projected onto the masterbatch rod 1 through the laser lens 402 to achieve heating. Figure 4 For the sake of clarity, the furnace chamber 5 and the multiple light-transmitting openings 501 on the furnace chamber 5 are not shown.

[0040] Embodiment 3: This embodiment still takes the zone melting silicon core growth system of using 100mm diameter masterbatch rod to draw 5 8mm diameter silicon cores as an example. Figure 1 and Figure 2 As shown, the silicon core drawing system includes a mother material rod 1, an induction heating coil 2, a silicon core 3 and a laser 4. Figure 3 As shown, 5 silicon cores are evenly distributed on the dividing circle outside the masterbatch rod, 5 silicon core drawing process holes are processed on the induction coil, and a coil positive electrode 201, a coil negative electrode 202 and a coil ground 203 are arranged on the induction coil.

[0041] The difference from Example 1 is that Figure 5 As shown, the laser of this embodiment adopts a vertical cavity surface emitting laser with a planar array output characteristic. This laser is referred to as VCSEL, which is a new type of array semiconductor laser. Its original output beam presents a uniform columnar shape and can be precisely controlled in different zones. When using this laser, multiple independent lasers can be set at the position of a single silicon core for superimposed irradiation to achieve heating of the masterbatch rod and the molten zone. Figure 5For the sake of clarity, the furnace chamber 5 and the multiple light-transmitting openings 501 on the furnace chamber 5 are not shown.

[0042] Embodiment 4: This embodiment still takes the zone melting silicon core growth system of using 100mm diameter masterbatch rod to draw 5 8mm diameter silicon cores as an example. Figure 1 and Figure 2 As shown, the silicon core drawing system includes a mother material rod 1, an induction heating coil 2, a silicon core 3 and a laser 4. Figure 3 As shown, 5 silicon cores are evenly distributed on the dividing circle outside the masterbatch rod, 5 silicon core drawing process holes are processed on the induction coil, and a coil positive electrode 201, a coil negative electrode 202 and a coil ground 203 are arranged on the induction coil.

[0043] When the laser masterbatch bar preheating function is not required, Figure 6 As shown, a laser can be used to emit a laser beam on the upper part of the induction heating coil, and the drawn silicon core can be irradiated from the light-transmitting port on the furnace chamber, and the irradiation position is close to the root of the silicon core of the induction heating coil, thereby increasing the temperature of the specific silicon core and the temperature of the melting zone below the silicon core, thereby reducing its growth diameter. The laser irradiation of the silicon core can be irradiated from one angle or from different angles at the same time to improve the heating uniformity.

[0044] Embodiment 5: This embodiment takes the zone melting silicon core growth system that uses a 100mm diameter master rod to draw 8 5mm diameter silicon cores as an example. The silicon core drawing system includes a master rod 1, an induction heating coil 2, a silicon core 3 and a laser 4. The 8 silicon cores are evenly distributed on the dividing circle outside the master rod 1, 8 silicon core drawing process holes are processed on the induction coil, and the coil positive electrode 201, coil negative electrode 202 and coil grounding 203 are set on the induction coil. 8 2kW straight line lasers 4 are set in the direction opposite to the 8 silicon cores.

[0045] Embodiment 6: This embodiment takes a zone melting silicon core growth system that uses a 100mm diameter master rod to draw four 12mm diameter silicon cores as an example. The silicon core drawing system includes a master rod 1, an induction heating coil 2, a silicon core 3, and a laser 4. The four silicon cores are evenly distributed on the dividing circle outside the master rod 1, four silicon core drawing process holes are processed on the induction coil, and the coil positive electrode 201, coil negative electrode 202 and coil grounding 203 are set on the induction coil. Four 2kW line lasers 4 are set in the direction opposite to the four silicon cores.

Claims

1. A laser heating device for accurately controlling the temperature of the silicon material melting zone and the diameter of the silicon core, characterized in that: The invention comprises a furnace chamber (5), wherein an induction heating coil (2) is arranged inside the furnace chamber (5) for heating the master material rod (1) as a whole; a plurality of lasers (4) are arranged outside the furnace chamber (5), and the lasers (4) are used to preheat the master material rod (1), or to heat the master material rod (1) in sections, or to heat the bottom of the drawn silicon core (3); a plurality of light-transmitting openings (501) are evenly arranged on the side wall of the furnace chamber (5), and a laser beam emitted by the laser (4) is irradiated into the furnace chamber (5) through the light-transmitting openings (501), thereby heating the master material rod (1).

2. The laser heating device for accurately controlling the temperature of the silicon material melting zone and the silicon core diameter according to claim 1 is characterized in that: The laser (4) emits a laser beam in a straight-line laser output mode with a certain opening angle.

3. The laser heating device for accurately controlling the temperature of the silicon material melting zone and the silicon core diameter according to claim 1 is characterized in that: The laser (4) is a fiber-optic transmission laser, comprising a laser generator (404), wherein the laser generator (404) is connected to a laser lens (402) via a transmission optical fiber (403).

4. The laser heating device for accurately controlling the temperature of the silicon material melting zone and the silicon core diameter according to claim 1, characterized in that: The laser (4) is a vertical cavity surface emitting laser with a planar array output characteristic, and the number of lasers (4) arranged in the same area to be heated of the masterbatch rod (1) is one or more.

5. The laser heating device for accurately controlling the temperature of the silicon material melting zone and the silicon core diameter according to claim 1, characterized in that: An adjustment mechanism (6) is provided below the laser (4), and the adjustment mechanism (6) is used to adjust the height of the laser (4) and the distance between the laser (4) and the furnace chamber (5).

6. The laser heating device for accurately controlling the temperature of the silicon material melting zone and the silicon core diameter according to claim 5, characterized in that: The adjustment mechanism (6) comprises a base, a surface of the base is provided with a slide rail, a sliding block for use with the slide rail is sleeved on the slide rail, and the sliding block is fixed below the laser (4).

7. A laser heating method for accurately controlling the temperature of the silicon material melting zone and the diameter of the silicon core, characterized in that: Using the laser heating device as described in any one of claims 1 to 6, during the silicon core drawing process, a plurality of uniformly distributed lasers (4) are used to preheat the master rod (1), and after the silicon material at the top of the master rod (1) is heated and conductive, the master rod (1) is heated as a whole using an induction heating coil (2). After a molten zone is formed at the top of the master rod (1), a plurality of lasers (4) are used simultaneously to heat the molten zone in different areas, thereby accurately controlling the diameter of the silicon core (3) formed in each molten zone.

8. The laser heating method for accurately controlling the silicon material melting zone temperature and silicon core diameter according to claim 7, characterized in that: A plurality of lasers (4) emit laser beams to irradiate the master material rod (1), and the irradiation range of the plurality of laser beams covers 360 degrees around the master material rod (1).

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