Saddle-shaped permanent magnetic field device for silicon single crystal growth

Abstract

The invention provides a saddle-shaped permanent magnetic field device for silicon single crystal growth, and belongs to the technical field of semiconductor manufacturing, the saddle-shaped permanent magnetic field device comprises a saddle-shaped single crystal permanent magnet, a walking mechanism, a lifting mechanism and a support, the saddle-shaped single crystal permanent magnet is composed of a left yoke plate, a right yoke plate, a left saddle-shaped magnetic pole, a right saddle-shaped magnetic pole, a left jackscrew, a right jackscrew and a concentrating flux plate; the single-crystal permanent magnet magnetic poles are of a saddle-shaped structure, the uniformity of the magnetic field intensity within the circumferential range is greatly improved, the resistivity of the single crystal and the uniformity of impurities can be better improved, the lifting mechanism can integrally move the magnetic field up and down, initial position adjustment can be achieved, and micro up-down movement can be achieved through the internal design of the left and right saddle-shaped magnetic poles; the center of the magnetic pole can be adjusted according to the actual height of the molten silicon liquid level, the magnetic pole adopts a vacuum infusion process, so that a magnetic material is isolated from air and insulated, the service life is prolonged, the left and right jackscrew structures can adjust the distance between the magnetic poles, the magnetic field intensity is adjustable, and the applicability is improved. The problems that the magnetic field intensity of a conventional single-crystal permanent magnetic field cannot be adjusted, and the permanent magnetic field cannot be closed are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a saddle-shaped permanent magnetic field device for growing silicon single crystals. Background Art

[0002] At present, semiconductor silicon wafers are divided into 4-6 inches, 8 inches and 12 inches according to their sizes. 4-6 inches are mainly used in the manufacture of diodes, triodes and power devices, 8 inches are mainly used in power devices, automotive chips, power managers, display drivers and fingerprint recognition chips, and 12 inches are mainly used in high-end fields such as integrated circuits or processing chips. The domestic 4-6 inch single crystal growth technology has matured, but with the continuous upgrading of chip products and the continuous improvement of process technology, the quality requirements for single crystals are also higher, and the requirements for single crystal growth equipment are also higher. At present, the main magnetic fields used in the growth of 4-6 inch single crystals in the market are single crystal electromagnetic fields and single crystal permanent magnetic fields. Single crystal electromagnetic fields have high energy consumption, high maintenance costs, and short service life. They have gradually been replaced by permanent magnets. The magnetic field strength of conventional single crystal permanent magnetic fields cannot be adjusted, and it cannot be flexibly matched with process requirements. The permanent magnetic field cannot be turned off, and the operation of the single crystal furnace during maintenance becomes more difficult, and there are greater safety hazards. In addition, the magnetic field structure of a conventional single crystal permanent magnetic field is a left and right magnetic pole structure, and the magnetic field uniformity is poor. The magnetic field intensity is stronger near the magnetic poles, and the magnetic field intensity is weaker on the other two sides. The silicon solution is subjected to uneven magnetic field forces within the circumference, affecting the uniformity of resistivity. The magnetic field height at the center of the single crystal permanent magnetic field is also not adjustable, and there is no way to match a variety of thermal field sizes, which limits its use. Summary of the invention

[0003] Based on the problems existing in the prior art, the present invention proposes a saddle-shaped permanent magnetic field device for growing silicon single crystals, which solves the problems in the prior art that the magnetic field strength of the conventional single crystal permanent magnetic field cannot be adjusted, cannot be flexibly coordinated with process requirements, the permanent magnetic field cannot be turned off, the operation of the single crystal furnace is more difficult during maintenance, and there are major safety hazards.

[0004] According to the technical solution of the present invention, the present invention proposes a saddle-shaped permanent magnetic field device for growing silicon single crystals, which includes a saddle-shaped single crystal permanent magnet, a walking mechanism, a bracket assembly and a lifting mechanism; the saddle-shaped single crystal permanent magnet is fixed on a bearing seat with a connecting plate and a fixed pulley of the walking mechanism, and the bearing seat includes an active bearing seat and a driven bearing seat; the two guide rails of the walking mechanism are fixed on the bracket to form a C-shaped overall structure installed on both sides of the single crystal furnace.

[0005] The saddle-shaped single crystal permanent magnet comprises a left magnetic pole and a right magnetic pole, and the center of the magnetic field formed by the left magnetic pole and the right magnetic pole is located 20 mm below the liquid level of the molten silicon in the single crystal furnace.

[0006] Furthermore, the saddle-shaped single crystal permanent magnet includes a left yoke plate, a left magnetic pole, a right magnetic pole, a right yoke plate, a right top wire, a magnetic conductive plate and a left top wire; the material of the left yoke plate, the left magnetic pole, the right magnetic pole, the right yoke plate and the magnetic conductive plate is high magnetic permeability DT4 electrical pure iron; the left yoke plate is connected to the left magnetic pole, the right magnetic pole is connected to the right yoke plate, the left yoke plate is connected to the magnetic conductive plate, and the right yoke plate is connected to the magnetic conductive plate to form a C-shaped whole.

[0007] Furthermore, the left magnetic pole and the right magnetic pole of the saddle-shaped single crystal permanent magnet are respectively an N pole and an S pole, and have opposite polarities.

[0008] Furthermore, the direction of the magnetic induction lines of the saddle-shaped single crystal permanent magnet is from the N pole of the left magnetic pole through the single crystal furnace to the S pole of the right magnetic pole, then to the right yoke plate, through the magnetic conductive plate, back to the left yoke plate, and then to the left magnetic pole, forming a loop. The magnetic field strength at the center point of the horizontal distance between the centers of the left magnetic pole and the right magnetic pole is mainly effective in crystal pulling, and the magnetic field strength is any value between 800GS and 1500GS.

[0009] Furthermore, the right top screw and the left top screw of the saddle-shaped single crystal permanent magnet are respectively installed at the connection between the left yoke plate and the right yoke plate on both sides of the magnetic conductive plate, and the connection position of the left yoke plate and the right yoke plate with the magnetic conductive plate is pushed open or reduced by the right top screw and the left top screw, and then a pad made of DT4 electrical pure iron is added or reduced between the left yoke plate and the right yoke plate and the magnetic conductive plate. When a loop is formed, the distance between the left magnetic pole and the right magnetic pole is changed, thereby increasing or decreasing the central magnetic field strength.

[0010] Preferably, the left and right poles of the saddle-shaped single crystal permanent magnet are composed of a rare earth alloy magnet block, an upper top screw, a pole guide rail, a lower top screw, a pole slider, and a pole cavity; the pole cavity is made of stainless steel and has a stepped shape, the pole slider is made of DT4 electrical pure iron, the rare earth alloy magnet blocks are stacked in rows in the pole cavity, the pole cavity is connected to the pole slider, the pole guide rail is connected to the left and right yoke plates, the pole cavity and the pole slider are installed on the pole guide rail, and the position is fixed by the upper top screw and the lower top screw; the left and right poles are made of a vacuum infusion process, after the rare earth alloy magnet blocks are assembled, the pole is placed in a curing furnace as a whole, vacuumed, and then epoxy is infused, the epoxy using HY750, and after the infusion is completed, the pole is transferred to the curing furnace, the temperature of the curing furnace is set to 40 degrees, and a 4-hour curing treatment and one-piece molding are performed.

[0011] Preferably, the left magnetic pole and the right magnetic pole of the saddle-shaped single crystal permanent magnet are saddle-shaped structures to improve the circumferential uniformity of the magnetic field.

[0012] Furthermore, the left magnetic pole and the right magnetic pole of the saddle-shaped single crystal permanent magnet can adjust the upper and lower positions of the magnetic poles through the upper top screw and the lower top screw, thereby adjusting the magnetic field position of the magnetic field center.

[0013] Preferably, both ends of the transmission shaft of the walking mechanism are fixed on the active bearing seat and the driven bearing seat, and the active pulley and the driven pulley are fixed on the outside of the transmission shaft. The active pulley and the driven pulley are installed on the guide rail, and one end of the transmission shaft is connected to the drive motor.

[0014] Compared with the prior art, the beneficial technical effects of the saddle-shaped permanent magnetic field device for silicon single crystal growth of the present invention are as follows:

[0015] 1. The saddle-shaped permanent magnetic field device for silicon single crystal growth provided by the present invention increases the uniformity of the circumferential magnetic field strength in the single crystal furnace area through the saddle-shaped magnetic pole structure, and realizes the forward and backward movement and up and down lifting of the single crystal magnet through the walking mechanism and the lifting mechanism, which is convenient for maintenance; the magnetic pole is moved up and down slightly through the magnetic pole slide rail to match the thermal field and crucible sizes of different sizes; the magnetic pole spacing is adjustable through the left and right yoke plate top wire structure, thereby changing the magnetic field strength, and can be matched with different crystal pulling processes to realize a multifunctional, energy-saving and uniform single crystal magnet.

[0016] 2. The saddle-shaped permanent magnetic field device for silicon single crystal growth provided by the present invention has an adjustable magnetic field strength, can flexibly meet process requirements, the permanent magnetic field can be turned off and has a high safety factor.

[0017] 3. The saddle-shaped permanent magnetic field device for single crystal growth provided by the present invention increases the walking mechanism and the lifting mechanism at the bottom of the magnetic field so that the magnetic field can move back and forth and up and down, which is convenient for maintenance. The magnetic poles can be fine-tuned up and down through the top wire and the slide rail, which can better match the thermal fields and crucible heights of different sizes. By increasing the top wire mechanism between the two yoke plates and the magnetic conductive plate, the distance between the two magnetic poles can be adjusted, thereby achieving adjustable magnetic field strength and meeting more crystal pulling needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a saddle-shaped single-crystal permanent magnet according to the present invention;

[0019] Figure 2a A schematic diagram of the working position of a saddle-shaped single crystal permanent magnet according to the present invention;

[0020] Figure 2b A schematic diagram of the maintenance position of a saddle-shaped single-crystal permanent magnet according to the present invention;

[0021] Figure 3 A schematic diagram of the three-dimensional structure of the walking mechanism according to the present invention;

[0022] Figure 4 It is a schematic diagram of the structure of a saddle-shaped permanent magnet according to the present invention;

[0023] Figure 5 A schematic diagram of the magnetic pole structure of a saddle-shaped permanent magnet according to the present invention;

[0024] Figure 6a A schematic top view of a lifting mechanism according to the present invention;

[0025] Figure 6b It is a front view schematic diagram of the lifting mechanism according to the present invention.

[0026] Description of the drawings in the accompanying drawings: 1-1, single crystal furnace; 1-2, saddle-shaped single crystal permanent magnet; 1-3, walking mechanism; 1-4, bracket assembly; 1-5, lifting mechanism; 3-1, driving motor; 3-2, active pulley; 3-3, guide rail; 3-4, active bearing seat; 3-5, transmission shaft; 3-6, rack; 3-7, driven pulley; 3-8, driven bearing seat; 3-9, fixed pulley; 4-1, left yoke plate; 4 -2, left magnetic pole; 4-3, right magnetic pole; 4-4, right yoke plate; 4-5, right top screw; 4-6, magnetic conductive plate; 4-7, left top screw; 5-1, rare earth alloy magnet block; 5-2, upper top screw; 5-3, magnetic pole guide rail; 5-4, lower top screw; 5-5, magnetic pole slider; 5-6, magnetic pole cavity; 6-1, reduction motor; 6-2, coupling; 6-3 transmission shaft; 6-4, reducer; 6-5, screw lift. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0029] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0030] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0031] like Figure 1-6b As shown, the present invention provides a saddle-shaped permanent magnetic field device for growing silicon single crystals, which includes a saddle-shaped single crystal permanent magnet 1-2, a walking mechanism 1-3, a support assembly 1-4 and a lifting mechanism 1-5.

[0032] Saddle-shaped single crystal permanent magnets 1-2 are installed on both sides of the single crystal furnace 1-1. The saddle-shaped single crystal permanent magnets 1-2 form a magnetic field for processing silicon single crystals. The single crystal furnace 1-1 contains molten silicon single crystal melt. The center point of the magnetic field is located below the liquid surface of the silicon single crystal melt. Preferably, the center point of the magnetic field is at any height of 8mm to 22mm from the liquid surface of the silicon single crystal melt; or preferably, the center point of the magnetic field is at any position of 0mm to 20mm from the liquid surface of the silicon single crystal melt, that is, the center point of the magnetic field is located at any position within 20mm from the liquid surface of the silicon single crystal melt.

[0033] The saddle-shaped single crystal permanent magnet uses a rare earth alloy as a magnetic source to provide a stable and uniform magnetic field for single crystal growth. The magnetic field can effectively suppress melt fluctuations and reduce the scouring of the crucible caused by melt fluctuations. The saddle-shaped structure can make the silicon melt more evenly stressed, further reducing fluctuations, and can also improve the resistance uniformity of silicon single crystals, thereby improving the consistency of single crystal products. In the prior art, oxygen formed by melt scouring the crucible leads to the formation of defects in single crystal silicon rods, while the magnetic field provided by the saddle-shaped single crystal permanent magnet 1-2 in the present invention does not have a structure of melt scouring the crucible, so it can effectively improve the quality of single crystals, reduce single crystal defects, and improve resistance uniformity; and the saddle-shaped single crystal permanent magnet does not require any power consumption, thereby reducing the cost of crystal pulling.

[0034] The saddle-shaped single crystal permanent magnet 1-2 is mainly composed of two saddle-shaped magnetic poles, two yoke plates and a magnetic conductive plate. The saddle-shaped magnetic poles are installed on the yoke plates. The yoke plates are rectangular thick iron plate welded structures, and the magnetic conductive plates are rectangular thick iron plate joint structures. There are connecting plates at both ends of the magnetic conductive plates, which are connected to the yoke plates to form a C-shaped structure. One of the two magnetic poles is an N pole, and the other is an S pole. The magnetic poles are saddle-shaped structures. Inside the saddle structure, rectangular alloy magnetic blocks are arranged in a stepped shape to form magnetic poles. The rectangular alloy magnetic blocks are installed in a stepped stainless steel cavity. The stepped stainless steel cavity is a symmetrical structure with a low middle and high sides, forming a saddle-shaped magnetic pole structure as a whole. The magnetic field extends from the N pole to the S pole, then through the yoke plate to the magnetic conductive plate, and then back to the magnetic pole, forming a magnetic circuit, so that the magnetic field is concentrated in the single crystal furnace area. A top screw structure is provided at the connection between the yoke plate and the magnetic conductive plate of the saddle-shaped single crystal permanent magnet 1-2, the purpose of which is to change the distance between the magnetic conductive plate and the yoke plate through the top screw structure, thereby changing the distance between the two magnetic poles. When the magnetic pole distance increases, the central magnetic field strength will decrease, so that the crystal pulling process can be matched, the appropriate magnetic field strength can be selected, and the magnetic field application is more flexible. The connection between the magnetic pole and the yoke plate adopts the form of a guide rail, and top screws are added up and down, so that the magnetic pole can be fine-tuned up and down, so that the melt liquid level position can be better matched and a better crystal pulling effect can be obtained.

[0035] The walking mechanism 1-3 can make the saddle-shaped permanent magnetic field 1-2 move forward and backward flexibly, which can improve the safety of the single crystal furnace maintenance and reduce the difficulty of maintenance. Because there are certain safety hazards in working under the magnetic field environment, the maintenance tools must be non-magnetic, and the maintenance personnel cannot wear any iron parts; on the other hand, the magnetic field is not required in the melting process, and the magnetic field will increase the melting time. Only by increasing the heating power can the melting time be increased and the energy consumption is increased. Therefore, in the melting stage, the saddle-shaped permanent magnet can be moved to the maintenance position, which will not affect the melting efficiency.

[0036] The driving motor 3-1 of the walking mechanism 1-3 is a reduction motor, and the driving motor 3-1 has a brake function, which can brake in time during operation. The driven pulley 3-7 has a gear structure on the outside, which can mesh with the rack and drive the pulley to make the saddle-shaped permanent magnetic field move smoothly on the slide rail.

[0037] The bracket components 1-4 play a supporting role for all components, are fixed to the ground with expansion screws, adopt a 4-square steel column structure, are connected into a whole by tie rods, and are connected to the lifting mechanism at the top.

[0038] The lifting mechanism 1-5 can make the saddle magnet move up and down in the vertical direction of the single crystal furnace. When the single crystal furnace uses different thermal fields and crucibles, the liquid level of the melt will be adjusted and some of the adjustment distances are very large. With the lifting mechanism, the center height of the magnetic pole can be quickly adjusted to match the melt liquid level. It is convenient and quick to use and improves work efficiency.

[0039] The lifting mechanism 1-5 is a C-shaped structure as a whole, which matches the shape of the saddle-shaped permanent magnetic field and is easy to install. The reduction motor 6-1 is a two-side shaft structure, the reducer 6-4 is a right-angle structure, the reducer 6-4 rotates the transmission direction 90 degrees, and the four screw lifts 6-5 are worm screw structures. The upper ends of the four screw lifts 6-5 are connected by a connecting plate, and the lower ends are directly connected to the load.

[0040] The saddle-shaped single crystal permanent magnet 1-2 is fixed on the bearing seat with a connecting plate and the fixed pulley 3-9 of the walking mechanism 1-3, and the bearing seat includes an active bearing seat 3-4 and a driven bearing seat 3-7; the two guide rails 3-3 of the walking mechanism 1-3 are fixed on the bracket 1-4, forming a C-shaped overall structure installed on both sides of the single crystal furnace 1-1. The saddle-shaped single crystal permanent magnet 1-2 is installed on both sides of the single crystal furnace 1-1, and the magnetic field formed by the saddle-shaped single crystal permanent magnet 1-2 is used to process silicon single crystals. The single crystal furnace 1-1 contains molten silicon single crystal melt, and the center point of the magnetic field is located below the liquid surface of the silicon single crystal melt, preferably the center point of the magnetic field is at any height of 8mm to 22mm from the liquid surface of the silicon single crystal melt; or preferably the center point of the magnetic field is at any position of 0mm to 20mm from the liquid surface of the silicon single crystal melt, that is, the center point of the magnetic field is located at any position within 20mm from the liquid surface of the silicon single crystal melt. The left magnetic pole 4-2 of the saddle-shaped single crystal permanent magnet 1-2 is an N pole, and the right magnetic pole 4-3 of the saddle-shaped single crystal permanent magnet 1-2 is an S pole, with opposite polarities. The left magnetic pole 4-2 and the right magnetic pole 4-3 of the saddle-shaped single crystal permanent magnet 1-2 are composed of a rare earth alloy magnetic block 5-1, an upper top wire 5-2, a magnetic pole guide rail 5-3, a lower top wire 5-4, a magnetic pole slider 5-5 and a magnetic pole cavity 5-6. The magnetic pole cavity 5-6 is made of stainless steel and has a stepped shape. The material of the magnetic pole slider 5-5 is DT4 electrical pure iron, the rare earth alloy magnet block 5-1 is stacked in a row into the magnetic pole cavity 5-6, the magnetic pole cavity 5-6 is connected to the magnetic pole slider 5-5, the magnetic pole guide rail 5-3 is connected to the left and right yoke plates, the magnetic pole cavity 5-6 and the magnetic pole slider 5-5 are installed on the magnetic pole guide rail 5-3, and the magnetic pole cavity 5-6 and the magnetic pole slider 5-5 are fixed in position by the upper top screw 5-2 and the lower top screw 5-4. The left magnetic pole 4-2 and the right magnetic pole 4-3 adopt a vacuum infusion process. After assembling the rare earth alloy magnet block 5-1, the magnetic pole is placed in a curing furnace as a whole, vacuumized, and then epoxy is infused. The epoxy adopts HY750. After the infusion is completed, the magnetic pole is transferred to the curing furnace. The temperature of the curing furnace is set to 40 degrees, and a 4-hour curing treatment and integrated molding are performed. The left magnetic pole 4-2 and the right magnetic pole 4-3 of the saddle-shaped single crystal permanent magnet 1-2 are saddle-shaped structures to improve the circumferential uniformity of the magnetic field. The left magnetic pole 4-2 and the right magnetic pole 4-3 of the saddle-shaped single crystal permanent magnet 1-2 can adjust the upper and lower positions of the magnetic poles through the upper top screw 5-2 and the lower top screw 5-4, thereby adjusting the magnetic field center magnetic field position.

[0041] The direction of the magnetic induction line of the saddle-shaped single crystal permanent magnet 1-2 is from the N pole of the left magnetic pole 4-2 through the single crystal furnace to the S pole of the right magnetic pole 4-3, then to the right yoke plate 4-4, through the magnetic conductive plate 4-6, back to the left yoke plate 4-1, and then to the left magnetic pole 4-2, forming a loop. The main factor that affects the crystal pulling is the magnetic field strength at the center point of the horizontal distance between the left magnetic pole 4-2 and the right magnetic pole 4-3. The magnetic field strength is any Gauss between 800GS and 1500GS. The right top screw 4-5 and the left top screw 4-7 of the saddle-shaped single crystal permanent magnet 1-2 are installed at the connection between the left yoke plate 4-1 and the right yoke plate 4-4 on both sides of the magnetic conductive plate 4-6. The connection position of the left yoke plate 4-1 and the right yoke plate 4-4 with the magnetic conductive plate 4-6 can be pushed open or reduced by the right top screw 4-5 and the left top screw 4-7, and then the pads are added or reduced between the left yoke plate 4-1 and the right yoke plate 4-4 and the magnetic conductive plate 4-6. The pads are made of DT4 electrical pure iron. When a loop is formed, the distance between the left magnetic pole 4-2 and the right magnetic pole 4-3 is changed, thereby increasing or decreasing the central magnetic field strength.

[0042] The walking mechanism 1-3 is installed on the lifting mechanism 1-5, the lifting mechanism 1-5 is installed on the bracket assembly 1-4, the saddle-shaped single crystal permanent magnet 1-2 is installed on the walking mechanism 1-3, forming a C-shaped whole installed on both sides of the 1-1 single crystal furnace, the center point of the magnetic field formed by the single crystal permanent magnet 1-2 is located 20mm below the silicon melt liquid surface, the driving motor 3-1 of the walking mechanism 1-3 drives the transmission shaft 3-5, and the two ends of the transmission shaft 3-5 are fixed to the active bearing seat 3-4 and the slave On the active bearing seat 3-8, the driving pulley 3-2 and the driven pulley 3-7 are fixed on the transmission shaft 3-5 on the outside, the driving pulley 3-2 and the driven pulley 3-7 are installed on the guide rail 3-3, the transmission shaft 3-5 drives the active pulley 3-2 and the driven pulley 3-7 to roll, and the driven pulley 3-7 rolls. A gear is fixed on the outside, and the gear and rack 3-6 move. The walking mechanism 1-3 drives the overall saddle-shaped single crystal permanent magnet 1-2 to move freely forward and backward, and freely switch back and forth between the working position and the maintenance position. The transmission shaft 3-5 of the walking mechanism 1-3 is fixed on the active bearing seat 3-4 and the driven bearing seat 3-8 at both ends, and the active pulley 3-2 and the driven pulley 3-7 are fixed on the transmission shaft 3-5 on the outside, the active pulley 3-2 and the driven pulley 3-7 are installed on the guide rail 3-3, and one end of the transmission shaft 3-5 is connected to the drive motor 3-1.

[0043] The lower part of the lifting mechanism 1-5 is connected to the bracket, and the reduction motor 6-1 drives the coupling 6-2. Through the transmission shaft and the reduction motor 6-1, the four screw lifts are lifted and lowered at the same time, so that the saddle-type single crystal permanent magnet can be adjusted up and down.

[0044] like Figure 1As shown, the bottom of the saddle-shaped single crystal permanent magnet is connected to the active pulley and the driven pulley of the walking mechanism by bolts, the guide rail under the walking mechanism is connected to the lifting mechanism by bolts, and the lifting mechanism is connected to the bracket by bolts to form a C-shaped whole, which is installed on both sides of the single crystal furnace. The saddle-shaped permanent magnetic field can provide a stable, energy-free horizontal magnetic field for single crystal growth, and the walking mechanism 1-3 can make the saddle-shaped permanent magnetic field 1-2 move flexibly back and forth. On the one hand, it can improve the safety of single crystal furnace maintenance and reduce the difficulty of maintenance, because there are certain safety hazards in working under a magnetic field environment, and the maintenance tools must be non-magnetic, and the maintenance personnel cannot wear any iron parts; on the other hand, the magnetic field is not required in the melting process. The magnetic field will increase the melting time. Only by increasing the heating power can the melting time be increased, which increases energy consumption. Therefore, in the melting stage, the saddle-shaped permanent magnet can be moved to the maintenance position, which will not affect the melting efficiency. The lifting mechanism 1-5 can make the saddle magnet move up and down in the vertical direction of the single crystal furnace. When the single crystal furnace uses different thermal fields and crucibles, the liquid level of the melt will be adjusted and some of the distances required for adjustment are very large. With the lifting mechanism, the height of the magnetic pole center can be quickly adjusted to match the melt level. It is convenient and fast to use and improves work efficiency. The bracket assembly 1-4 plays a supporting role for all components. The bracket assembly 1-4 is fixed with ground expansion screws and adopts a 4-square steel column structure, which is connected into a whole by tie bars to provide stable support.

[0045] like Figure 2a and Figure 2b As shown, the walking mechanism 1-3 can make the saddle-shaped permanent magnetic field 1-2 move forward and backward flexibly. Figure 2b As shown, the magnetic field is moved to the area outside the single crystal furnace through the walking mechanism. On the one hand, it can improve the safety of the single crystal furnace maintenance and reduce the difficulty of maintenance. Because there are certain safety hazards in working under the magnetic field environment, the maintenance tools must be non-magnetic and the maintenance personnel cannot wear any iron parts. On the other hand, the magnetic field is not required in the melting process. The magnetic field will increase the melting time instead. Only by increasing the heating power can the melting time be increased, which increases the energy consumption. Therefore, in the melting stage, the saddle-shaped permanent magnet can be moved to the maintenance position, which will not affect the melting efficiency.

[0046] like Figure 3As shown, the driving motor 3-1 of the walking mechanism 1-3 drives the transmission shaft 3-5, and the two ends of the transmission shaft 3-5 are fixed on the active bearing seat 3-4 and the driven bearing seat 3-8. The active pulley 3-2 and the driven pulley 3-7 are fixed on the outside of the transmission shaft 3-5. The active pulley 3-2 and the driven pulley 3-7 are installed on the guide rail 3-3. The transmission shaft 3-5 drives the active pulley 3-2 and the driven pulley 3-7 to roll. A gear is fixed on the outside of the driven pulley roller 3-7, and the gear and rack 3-6 move. Through the above structure, the walking mechanism 1-3 can smoothly drive the overall saddle-shaped single crystal permanent magnet 1-2 to move freely forward and backward, and switch freely between the working position and the maintenance position.

[0047] like Figure 4 As shown, the saddle-shaped single crystal permanent magnet 1-2 includes a left yoke plate 4-1, a left magnetic pole 4-2, a right magnetic pole 4-3, a right yoke plate 4-4, a right top wire 4-5, a magnetic conductive plate 4-6 and a left top wire 4-7; the left yoke plate 4-1, the left magnetic pole 4-2, the right magnetic pole 4-3, the right yoke plate 4-4 and the magnetic conductive plate 4-6 are made of high magnetic permeability DT4 electrical pure iron; the left yoke plate 4-1 is connected to the left magnetic pole 4-2, the right magnetic pole 4-3 is connected to the right yoke plate 4-4, the left yoke plate 4-1 is connected to the magnetic conductive plate 4-6, and the right yoke plate 4-4 is connected to the magnetic conductive plate 4-6 to form a C-shaped whole.

[0048] The left magnetic pole 4-2 is installed on the left yoke plate 4-1 through the magnetic pole guide rail 5-3, and the right magnetic pole 4-3 is installed on the right yoke plate 4-4 through the magnetic pole guide rail 5-3. The left yoke plate 4-1 and the right yoke plate 4-4 are installed on both sides of the magnetic conductive plate 4-6. The right top screw 4-5 and the left top screw 4-7 are respectively installed on both sides of the magnetic conductive plate 4-6 and the connection between the left yoke plate 4-1 and the right yoke plate 4-4. The connection position of the left yoke plate 4-1 and the right yoke plate 4-4 and the magnetic conductive plate 4-6 can be pushed open or reduced by the right top screw 4-5 and the left top screw 4-7, and then the pad made of DT4 electrical pure iron is added or reduced between the left yoke plate 4-1 and the right yoke plate 4-4 and the magnetic conductive plate 4-6. When a loop is formed, the distance between the left magnetic pole 4-2 and the right magnetic pole 4-3 is changed, thereby increasing or decreasing the central magnetic field strength. In this embodiment, the left magnetic pole 4-2 and the right magnetic pole 4-3 are vacuum-infused epoxy-based, which reduces oxidation of the magnetic material in contact with air, increases heat insulation, and improves the service life of the equipment.

[0049] like Figure 5As shown, the left magnetic pole 4-2 and the right magnetic pole 4-3 are composed of a rare earth alloy magnetic block 5-1, an upper top wire 5-2, a magnetic pole guide rail 5-3, a lower top wire 5-4, a magnetic pole slider 5-5 and a magnetic pole cavity 5-6. The rare earth alloy magnetic blocks 5-1 are stacked in rows and installed in a stainless steel magnetic pole cavity 5-6. The stainless steel magnetic pole cavity 5-6 is designed to be a saddle-shaped step shape. The magnetic pole arrangement improves the uniformity of the magnetic field in the circumferential range of the magnetic field. The upper top wire 5-2 and the lower top wire 5-4 are installed and fixed on the yoke plate. The upper top wire 5-2 and the lower top wire 5-4 can be used to adjust the movement of the magnetic pole slider 5-5 on the magnetic pole guide rail 5-3, thereby adjusting the upper and lower positions of the magnetic pole cavity, changing the position of the magnetic pole center, so that the central magnetic field surface can move up and down to match the thermal field position.

[0050] like Figure 6a and Figure 6b As shown, the lifting mechanism 1-5 is connected to the bracket at the bottom, and the reduction motor 6-1 drives the coupling 6-2. Through the transmission shaft 3-5 and the reducer, the four screw lifts are lifted and lowered at the same time, so that the saddle-shaped single crystal permanent magnet can be adjusted up and down. The lifting mechanism 1-5 is a C-shaped structure as a whole, which matches the shape of the saddle-shaped permanent magnetic field and is easy to install. The reduction motor 6-1 is a shaft structure on both sides, and the reducer 6-4 is a right-angle structure, so that the transmission direction is rotated 90 degrees. The four screw lifts 6-5 are turbine screw structures. The upper ends of the four screw lifts 6-5 are connected by a connecting plate, and the lower ends are directly connected to the load. The turbine screw has a compact structure, a small volume, a stable operation, no noise, and can flexibly and reliably lift the single crystal permanent magnet. The two ends of the transmission shaft 6-3 are connected to the coupling 6-2, and the reduction motor 6-1 outputs a drive to rotate, and the transmission shaft 6-3 transmits the torque to the reducer 6-4, and finally transmits it to the screw lift 6-5, finally realizing up and down movement, playing the role of connecting and transmitting torque.

[0051] In summary, the saddle-shaped permanent magnetic field device for silicon single crystal growth provided by the present invention increases the uniformity of the circumferential magnetic field intensity in the single crystal furnace area through the saddle-shaped magnetic pole structure; the present invention realizes the forward and backward movement, up and down lifting of the single crystal magnet through the walking mechanism and the lifting mechanism, which is convenient for maintenance; the present invention realizes the upward and downward micro-movement of the magnetic pole through the magnetic pole slide rail, and cooperates with different sizes of thermal fields and crucible sizes; the present invention realizes adjustable magnetic pole spacing through the left and right yoke plate top wire structures, thereby changing the magnetic field strength, and can be matched with different crystal pulling processes to realize a multifunctional, energy-saving and uniform single crystal magnet.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A saddle-shaped permanent magnetic field device for growing silicon single crystals, characterized in that: It comprises a saddle-shaped single crystal permanent magnet (1-2), a walking mechanism (1-3), a support assembly (1-4) and a lifting mechanism (1-5); The saddle-shaped single crystal permanent magnet (1-2) is fixed on a bearing seat with a connecting plate and a fixed pulley (3-9) of a walking mechanism (1-3), wherein the bearing seat comprises an active bearing seat (3-4) and a driven bearing seat (3-7); two guide rails (3-3) of the walking mechanism (1-3) are fixed on a bracket (1-4), forming a C-shaped integral structure installed on both sides of the single crystal furnace (1-1).

2. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claim 1, characterized in that: The saddle-shaped single crystal permanent magnet (1-2) comprises a left magnetic pole (4-2) and a right magnetic pole (4-3), and the center of the magnetic field formed by the left magnetic pole (4-2) and the right magnetic pole (4-3) is located 20 mm below the liquid level of the molten silicon inside the single crystal furnace (1-1).

3. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claim 1, characterized in that: The saddle-shaped single crystal permanent magnet (1-2) comprises a left yoke plate (4-1), a left magnetic pole (4-2), a right magnetic pole (4-3), a right yoke plate (4-4), a right top wire (4-5), a magnetic conductive plate (4-6) and a left top wire (4-7); The left yoke plate (4-1), the left magnetic pole (4-2), the right magnetic pole (4-3), the right yoke plate (4-4) and the magnetic conductive plate (4-6) are made of high magnetic permeability DT4 electrical pure iron; The left yoke plate (4-1) is connected to the left magnetic pole (4-2), the right magnetic pole (4-3) is connected to the right yoke plate (4-4), the left yoke plate (4-1) is connected to the magnetic conductive plate (4-6), and the right yoke plate (4-4) is connected to the magnetic conductive plate (4-6), forming a C-shaped whole.

4. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claim 3, characterized in that: The left magnetic pole (4-2) and the right magnetic pole (4-3) of the saddle-shaped single crystal permanent magnet (1-2) are respectively an N pole and an S pole, and have opposite polarities.

5. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claims 3 to 4, characterized in that: The direction of the magnetic induction line of the saddle-shaped single crystal permanent magnet (1-2) is from the N pole of the left magnetic pole (4-2) through the single crystal furnace to the S pole of the right magnetic pole (4-3), then to the right yoke plate (4-4), through the magnetic conductive plate (4-6), back to the left yoke plate (4-1), and then to the left magnetic pole (4-2), forming a loop. The magnetic field strength at the center point of the horizontal distance between the centers of the left magnetic pole (4-2) and the right magnetic pole (4-3) acts on the crystal pulling, and the magnetic field strength is any value between 800GS and 1500GS.

6. The saddle-shaped permanent magnetic field device for growing a silicon single crystal according to any one of claims 3 to 5, characterized in that: The right top screw (4-5) and the left top screw (4-7) of the saddle-shaped single crystal permanent magnet (1-2) are respectively installed at the connection between the left yoke plate (4-1) and the right yoke plate (4-4) on both sides of the magnetic conductive plate (4-6); the connection between the left yoke plate (4-1) and the right yoke plate (4-4) and the magnetic conductive plate (4-6) is opened or reduced by the right top screw (4-5) and the left top screw (4-7); then, a pad made of DT4 electrical pure iron is added or reduced between the left yoke plate (4-1) and the right yoke plate (4-4) and the magnetic conductive plate (4-6); and the distance between the left magnetic pole (4-2) and the right magnetic pole (4-3) is changed when a loop is formed, thereby increasing or reducing the central magnetic field intensity.

7. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claims 3 to 6, characterized in that: The left magnetic pole (4-2) and the right magnetic pole (4-3) of the saddle-shaped single crystal permanent magnet (1-2) are composed of a rare earth alloy magnetic block (5-1), an upper top wire (5-2), a magnetic pole guide rail (5-3), a lower top wire (5-4), a magnetic pole slider (5-5), and a magnetic pole cavity (5-6); The magnetic pole cavity (5-6) is made of stainless steel and has a stepped shape. The material of the magnetic pole slider (5-5) is DT4 electrical pure iron. The rare earth alloy magnet blocks (5-1) are stacked in rows in the magnetic pole cavity (5-6). The magnetic pole cavity (5-6) is connected to the magnetic pole slider (5-5). The magnetic pole guide rail (5-3) is connected to the left and right yoke plates. The magnetic pole cavity (5-6) and the magnetic pole slider (5-5) are installed on the magnetic pole guide rail (5-3) and fixed in position by an upper top screw (5-2) and a lower top screw (5-4). The left magnetic pole (4-2) and the right magnetic pole (4-3) are formed by a vacuum infusion process. After the rare earth alloy magnetic block (5-1) is assembled, the magnetic pole is placed in a curing furnace as a whole. After vacuuming, epoxy is infused. The epoxy adopts HY750. After the infusion is completed, the magnetic pole is transferred to the curing furnace. The temperature of the curing furnace is set at 40 degrees. The curing treatment and integrated molding are carried out for 4 hours.

8. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claim 7, characterized in that: The left magnetic pole (4-2) and the right magnetic pole (4-3) of the saddle-shaped single crystal permanent magnet (1-2) are saddle-shaped structures, thereby improving the circumferential uniformity of the magnetic field.

9. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claims 3 to 8, characterized in that: The left magnetic pole (4-2) and the right magnetic pole (4-3) of the saddle-shaped single crystal permanent magnet (1-2) can adjust the upper and lower positions of the magnetic poles through an upper top screw (5-2) and a lower top screw (5-4), thereby adjusting the magnetic field position of the magnetic field center.

10. The saddle-shaped permanent magnetic field device for silicon single crystal growth according to claim 1, characterized in that: The two ends of the transmission shaft (3-5) of the walking mechanism (1-3) are fixed on the active bearing seat (3-4) and the driven bearing seat (3-8), and an active pulley (3-2) and a driven pulley (3-7) are fixed on the outer side of the transmission shaft (3-5), the active pulley (3-2) and the driven pulley (3-7) are installed on the guide rail (3-3), and one end of the transmission shaft (3-5) is connected to the driving motor (3-1).

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