Seed crystal lifting mechanism and crystal growth system

Abstract

The utility model relates to the technical field of crystal growth systems, in particular to a seed crystal lifting mechanism and a crystal growth system. The lifting mechanism comprises a support, a sliding table, a rotating shaft, a first driving device, a second driving device and a weighing sensor, the rotating shaft penetrates through the sliding table, the rotating shaft and the sliding table are relatively fixed in the first direction, and the rotating shaft can rotate relative to the sliding table; the sliding table is slidably connected with the support in the first direction, the first driving device is used for driving the sliding table to slide along the support, and the second driving device is used for driving the rotating shaft to rotate. The weighing sensor is arranged on the sliding table and is connected with the rotating shaft; the weighing sensor is used for detecting a pulling force value applied to the seed crystal by the rotating shaft. The lifting mechanism can accurately control the rotation of the seed crystal, the weight of the seed crystal and the contact height of the seed crystal and a solution, so that the crystal growth quality and efficiency are ensured.

Description

Technical Field

[0001] The present application relates to the technical field of crystal growth systems, and in particular to a seed crystal pulling mechanism and a crystal growth system. Background Art

[0002] The third generation semiconductor silicon carbide (SiC) has the characteristics of wide bandgap, high breakdown voltage, large saturation drift velocity, high thermal conductivity, etc., which is conducive to the application of high voltage, high temperature and high frequency power devices. Among them, the single crystal of the third generation semiconductor SiC can be produced by solution growth method. However, one of the key steps of this process is seeding, which involves placing the seed crystal in the solution to guide the growth of new single crystals. The quality of seeding directly affects the quality of the crystal. The pulling mechanism of the seed crystal of the existing solution growth method is simple, and manual operation is required. The quality of seeding depends on the practical experience of the operator, and the labor task of the operator is large, and the quality of seeding is unstable. Utility Model Content

[0003] The present application discloses a seed crystal pulling mechanism and a crystal growth system, so as to solve the problem that the existing seed crystal pulling mechanism needs to be manually operated and the seed crystal quality is unstable.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] In the first aspect, a seed crystal lifting mechanism includes a bracket, a slide, a rotating shaft, a first driving device, a second driving device and a weighing sensor, wherein the rotating shaft passes through the slide and is relatively fixed to the slide along a first direction, and the rotating shaft can rotate relative to the slide; the slide is slidably connected to the bracket along the first direction, the first driving device is used to drive the slide to slide along the bracket, and the second driving device is used to drive the rotating shaft to rotate; the weighing sensor is arranged on the slide and connected to the rotating shaft, and the weighing sensor is used to detect the pulling force applied by the rotating shaft to the seed crystal.

[0006] Furthermore, the slide is provided with a through hole which penetrates the slide along the axial direction of the rotating shaft, the rotating shaft passes through the through hole, and the rotating shaft and the slide are transmission-connected via a weighing sensor.

[0007] Furthermore, the lifting mechanism also includes a weighing plate and a magnetic fluid seal mounted on the rotating shaft, the magnetic fluid seal includes a stator and a rotor, the rotor rotates synchronously with the rotating shaft, and the stator is fixedly connected to the weighing plate; the weighing sensor includes a cantilever beam, one end of the cantilever beam is fixedly mounted on the slide, and the other end of the cantilever beam is connected to the weighing plate.

[0008] Furthermore, the pulling mechanism also includes a first bellows, a second bellows and a mounting plate which are sleeved on the rotating shaft. The mounting plate is used to be fixedly connected to the furnace cover of the growth furnace. The first bellows is arranged between the weighing plate and the slide, and the second bellows is arranged between the slide and the mounting plate.

[0009] Further, the lifting mechanism includes a rotary joint, and a first pipeline and a second pipeline disposed inside the rotating shaft. The first pipeline and the second pipeline are communicated and both extend along a first direction. The rotary joint is disposed at an end of the rotating shaft. The rotary joint includes a water inlet and a water outlet. The water inlet is communicated with the first pipeline, and the water outlet is communicated with the second pipeline.

[0010] Further, the first driving device includes a first driving member and a first slide rail disposed on the bracket. The sliding table is slidably connected to the first slide rail, and an output end of the first driving member is connected to the sliding table; and / or, the second driving device includes a second driving member and a transmission assembly. The transmission assembly includes a driving wheel, a driven wheel and a conveyor belt. The conveyor belt is sleeved on the driving wheel and the driven wheel. The driving wheel is connected to an output end of the second driving member, and the driven wheel is connected to the rotating shaft.

[0011] Further, the lifting mechanism further includes a speed reducer, and an output end of the second driving member is connected to the driving wheel through the speed reducer.

[0012] In a second aspect, the present application provides a crystal growth system, which includes a growth furnace and the lifting mechanism of the first aspect. The bracket is fixedly disposed on a furnace cover of the growth furnace.

[0013] Adopting the technical solution of the present application, the beneficial effects are as follows:

[0014] For the seed crystal lifting mechanism provided by the present application, the rotating shaft and the sliding table are relatively fixed along the first direction, and the rotating shaft is used to be connected to a carrying device of the seed crystal. Therefore, when the first driving device drives the sliding table to slide along the first direction, the rotating shaft can be driven to move along the first direction, so that the movement of the seed crystal along the first direction can be realized. At the same time, the second driving device can drive the rotating shaft to rotate through the transmission assembly, thereby driving the rotation of the seed crystal. In addition, the weighing sensor is connected to the rotating shaft and can detect the pulling force value applied by the rotating shaft to the seed crystal, and the weight of the seed crystal and the height of the seed crystal in contact with the solution can be calculated according to the pulling force value. The lifting mechanism can realize precise control of the rotation of the seed crystal, the weight of the seed crystal, and the height of the seed crystal in contact with the solution, thereby ensuring the quality and efficiency of crystal growth. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of a lifting mechanism according to an embodiment of the present application;

[0016] Figure 2 It is a schematic structural diagram of a lifting mechanism according to an embodiment of the present application;

[0017] Figure 3 It is a schematic structural diagram of a lifting mechanism according to an embodiment of the present application.

[0018] Reference numerals: 100 - sliding table; 200 - rotating shaft; 210 - first pipeline; 220 - second pipeline; 300 - first driving device; 320 - first slide rail; 330 - linear module; 340 - worm and worm gear reducer; 400 - second driving device; 410 - second driving member; 420 - transmission assembly; 421 - driving wheel; 422 - driven wheel; 423 - conveyor belt; 430 - reducer; 500 - weighing sensor; 510 - cantilever beam; 600 - bracket; 720 - locking screw; 800 - magnetic fluid seal; 810 - stator; 820 - rotor; 900 - mounting plate;

[0019] 10 - first bellows; 20 - second bellows; 30 - weighing plate; 40 - rotary joint;

[0020] 01 - water inlet; 02 - water outlet. Specific embodiments

[0021] In order to make the objectives, technical solutions, and advantages of this application clearer, the following will further describe this application in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0022] The application scenarios described in the embodiments of this application are for more clearly explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those of ordinary skill in the art know that with the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are equally applicable to similar technical problems. Among them, in the description of this application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0023] Figure 1 It is a schematic structural diagram of a lifting mechanism according to an embodiment of this application. Figure 2 It is a schematic structural diagram of a lifting mechanism according to an embodiment of this application. Figure 3 It is a schematic structural diagram of a lifting mechanism according to an embodiment of this application. Please refer to Figures 1 to 3 In an embodiment of this application, a lifting mechanism is provided, which includes a bracket 600, a sliding table 100, a rotating shaft 200, a first driving device 300, a second driving device 400, and a weighing sensor 500. Among them, the rotating shaft 200 penetrates through the sliding table 100 and is relatively fixed to the sliding table 100 along the first direction D1, and the rotating shaft 200 can rotate relative to the sliding table 100. The sliding table 100 is slidably connected to the bracket 600 along the first direction. The first driving device 300 is used to drive the sliding table 100 to slide along the bracket 600, and the second driving device 400 is used to drive the rotating shaft 200 to rotate.

[0024] The weighing sensor 500 is arranged on the slide 100 and connected to the rotating shaft 200. The weighing sensor 500 is used to detect the pulling force applied by the rotating shaft 200 to the seed crystal, and can calculate the weight of the seed crystal and the contact height of the seed crystal with the liquid surface according to the pulling force value, so as to adjust the contact height of the seed crystal with the solution to a preset height. The pulling mechanism in the present application can accurately control the contact height of the seed crystal with the liquid surface, so as to optimize the crystal growth conditions and improve the crystal quality.

[0025] Optionally, the slide 100 is provided with a through hole that penetrates the slide 100 along the axial direction of the rotating shaft 200, and the rotating shaft 200 passes through the through hole. The rotating shaft 200 and the slide 100 are connected by a transmission sensor 500. It can be understood that when the rotating shaft 200 rotates, there is no friction between the inner wall of the through hole and the rotating shaft 200, so that the slide 100 can drive the rotating shaft 200 to move along the first direction, and the weighing sensor 500 can also accurately detect the pulling force of the rotating shaft 200 on the seed crystal.

[0026] Reference Figure 3 The lifting mechanism also includes a weighing plate 30 and a magnetic fluid seal 800 which are sleeved on the rotating shaft 200. The magnetic fluid seal 800 includes a stator 810 and a rotor 820. The rotor 820 rotates synchronously with the rotating shaft 200. The stator 810 is fixedly connected to the weighing plate 30. The magnetic fluid fills the gap between the rotor 820 and the stator 810 to form a liquid sealing film.

[0027] Among them, the weighing sensor 500 includes a cantilever beam 510 and a strain gauge arranged on the cantilever beam 510, one end of the cantilever beam 510 is fixed to the slide 100, and the other end of the cantilever beam 510 is connected to the weighing plate 30. The force of the rotating shaft 200 along the first direction can be transmitted to the cantilever beam 510 through the weighing plate 30. The bending of the cantilever beam 510 will cause the strain gauge attached thereto to stretch or compress, which will cause the resistance of the strain gauge to change. The weighing sensor 500 can convert the resistance value into a corresponding tension value. The weighing sensor 500 in this application can monitor the tension value of the seed crystal in real time and accurately sense the weight change of the seed crystal support.

[0028] Continue to refer to Figure 3 The lifting mechanism further includes a first bellows 10, a second bellows 20 and a mounting plate 900 sleeved on the rotating shaft 200, the mounting plate 900 being used for being fixedly connected to the furnace cover of the growth furnace, the first bellows 10 being arranged between the weighing plate 30 and the slide 100, and the second bellows 20 being arranged between the slide 100 and the mounting plate 900. The first bellows 10 and the second bellows 20 are used to allow the slide 100 to move in the first direction while maintaining the sealing inside the first bellows 10 and the second bellows 20.

[0029] Continue to refer to Figure 2 and Figure 3 As shown in FIGS. 2 and 3, the lifting mechanism includes a rotary joint 40, and a first pipeline 210 and a second pipeline 220 disposed within the rotary shaft 200. The first pipeline 210 and the second pipeline 220 are in communication and both extend along a first direction. The rotary joint 40 is disposed at an end of the rotary shaft 200. The rotary joint 40 includes a water inlet 01 and a water outlet 02. The water inlet 01 is in communication with the first pipeline 210, and the water outlet 02 is in communication with the second pipeline 220. The coolant enters the first pipeline 210 through the water inlet 01, then flows to the second pipeline 220 and can flow out from the water outlet 02 to the drainage pipeline, thereby cooling the rotary shaft 200. Optionally, the second pipeline 220 is sleeved on the first pipeline 210, and the bottoms of the two are in communication, which can not only increase the contact area between the coolant in the first pipeline 210 and the coolant in the second pipeline 220, but also save space.

[0030] The rotary shaft 200 is made of stainless steel, so that the rotary shaft 200 can be welded and machined to ensure the centering accuracy of the rotary shaft 200 and avoid the rotary shaft 200 driving the seed crystal end cover to draw an arc.

[0031] Continue to refer to Figures 1 to 3 As shown in FIG. 4, the first driving device 300 includes a first driving member (not shown in the figure) and a first slide rail 320 disposed on the bracket 600. The slide table 100 is slidably connected to the first slide rail 320. The output end of the first driving member is connected to the slide table 100. The first driving member can drive the slide table 100 to move along the first direction D1. Among them, the first driving member can be a motor.

[0032] Optionally, the first driving device 300 further includes a linear module 330 disposed on the first slide rail 320. The lead screw in the linear module 330 is connected to the slide table 100 through a worm and worm gear reducer, and the worm and worm gear reducer can play a role in reducing the speed and increasing the torque.

[0033] As an alternative embodiment, the second driving device 400 includes a second driving member 410 and a transmission assembly 420. The transmission assembly 420 includes a driving wheel 421, a driven wheel 422 and a conveyor belt 423. The conveyor belt 423 is sleeved on the driving wheel 421 and the driven wheel 422. The driving wheel 421 is connected to the output end of the second driving member 410, and the driven wheel 422 is connected to the rotary shaft 200. The second driving member 410 drives the driving wheel 421 to rotate, and the driving wheel 421 drives the driven wheel 422 to rotate through the conveyor belt 423, thereby driving the rotary shaft 200 to rotate.

[0034] Among them, the diameter of the driving wheel 421 is smaller than the diameter of the driven wheel 422, and the conveyor belt 423 is a wedge belt. Among them, the second driving member 410 can be a motor.

[0035] Optionally, the lifting mechanism further includes a speed reducer 430, and the output end of the second driving member 410 is connected to the driving wheel 421 through the speed reducer 430. Among them, the speed reducer 430 can be a planetary speed reducer.

[0036] Based on the same technical concept, the embodiments in the present application further provide a crystal growth system, which includes a growth furnace and the lifting mechanism in various possible embodiments of the present application, and the bracket 600 is fixedly arranged on the furnace cover of the growth furnace.

[0037] Because it includes the lifting mechanism in the present application, the crystal growth system also has the ability to monitor the weight of the seed crystal in real time, monitor the pulling force of the rotating shaft 200 on the seed crystal, so as to accurately control the height of the contact between the seed crystal and the solution, and control the rotation speed of the seed crystal, improving the growth quality and stability of the crystal.

[0038] In summary, when using the lifting mechanism and the crystal growth system of the present application to grow single crystals, taking the liquid-phase method silicon carbide crystal growth process as an example, the specific steps may include the following:

[0039] After the silicon carbide material melts in the crucible, the first driving device 300 drives the rotating shaft 200 through the sliding table 100 to drive the seed crystal to quickly descend to a position 10 mm above the melt surface for baking. Before crystal seeding, it is considered that the solvent vapor solidifies on the surface of the seed crystal and etches the surface of the seed crystal. Subsequently, locally saturated SiC can be redeposited to form 15R-SiC, Si droplets and viscous SiC particles, and then the rotating shaft 200 slowly drives the seed crystal to immerse in the solution, and the change in the reading of the weighing sensor 500 is used to judge the height of the contact between the seed crystal and the solution, and then it is lifted to a certain height from the solution surface to form a meniscus of 0.2 - 3.5 mm. Since the ingot continuously grows and gains weight, the liquid level of the silicon carbide liquid continuously decreases, and the weighing sensor 500 can accurately detect the pulling force value of the rotating shaft 200 on the seed crystal and monitor the weight change of the seed crystal in real time.

[0040] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A seed crystal pulling mechanism, characterized in that: It includes a bracket, a slide, a rotating shaft, a first driving device, a second driving device and a weighing sensor, wherein: The rotating shaft passes through the slide and is relatively fixed to the slide along a first direction, and the rotating shaft can rotate relative to the slide; The slide is slidably connected to the bracket along the first direction, the first driving device is used to drive the slide to slide along the bracket, and the second driving device is used to drive the rotating shaft to rotate; The weighing sensor is arranged on the slide and connected to the rotating shaft, and the weighing sensor is used to detect the pulling force value applied by the rotating shaft to the seed crystal.

2. The lifting mechanism according to claim 1, characterized in that: The slide is provided with a through hole penetrating the slide along the axial direction of the rotating shaft, the rotating shaft passes through the through hole, and the rotating shaft and the slide are transmission-connected via the weighing sensor.

3. The lifting mechanism according to claim 2, characterized in that: The lifting mechanism further comprises a weighing plate and a magnetic fluid seal sleeved on the rotating shaft, wherein the magnetic fluid seal comprises a stator and a rotor, wherein the rotor rotates synchronously with the rotating shaft, and the stator is fixedly connected to the weighing plate; The weighing sensor comprises a cantilever beam, one end of the cantilever beam is fixedly arranged on the slide table, and the other end of the cantilever beam is connected to the weighing plate.

4. The lifting mechanism according to claim 3, characterized in that: The lifting mechanism also includes a first bellows, a second bellows and a mounting plate which are sleeved on the rotating shaft. The mounting plate is used to be fixedly connected to the furnace cover of the growth furnace. The first bellows is arranged between the weighing plate and the slide, and the second bellows is arranged between the slide and the mounting plate.

5. The lifting mechanism according to claim 1, characterized in that: The lifting mechanism includes a rotating joint and a first pipeline and a second pipeline arranged in the rotating shaft, the first pipeline and the second pipeline are connected and both extend along the first direction, the rotating joint is arranged at the end of the rotating shaft, the rotating joint includes a water inlet and a water outlet, the water inlet is connected to the first pipeline, and the water outlet is connected to the second pipeline.

6. The lifting mechanism according to claim 1, characterized in that: The first driving device comprises a first driving member and a first slide rail provided on the bracket, the slide table is slidably connected to the first slide rail, and the output end of the first driving member is connected to the slide table; And / or, the second driving device includes a second driving member and a transmission assembly, the transmission assembly includes a driving wheel, a passive wheel and a conveyor belt, the conveyor belt is sleeved on the driving wheel and the passive wheel, the driving wheel is connected to the output end of the second driving member, and the passive wheel is connected to the rotating shaft.

7. The lifting mechanism according to claim 6, characterized in that: The lifting mechanism further includes a reducer, and the output end of the second driving member is connected to the driving wheel through the reducer.

8. A crystal growth system, characterized in that: It comprises a growth furnace and the lifting mechanism as claimed in any one of claims 1 to 7, wherein the bracket is fixed to the furnace cover of the growth furnace.

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