Method and device for improving thermal field uniformity of large-size silicon carbide

Abstract

The invention relates to the technical field of semiconductor material preparation, in particular to a method and device for improving the uniformity of a large-size silicon carbide temperature field, and the method comprises the steps: obtaining axial and radial temperature data in real time through a distributed sensor network, dynamically compensating the temperature field through a multi-source cooperative heating system, and calculating compensation parameters based on a thermal-electromagnetic coupling model. And synchronously driving the dynamic heat preservation structure, carrying out analog simulation on the temperature field, and designing the structure of the furnace body. Three layers of induction coils are arranged at the top in the furnace body, an infrared radiation plate is arranged at the bottom in the furnace body, the porosity of a porous silicon carbide ceramic plate is continuously adjusted through shape memory alloy, and under the cooperation of a two-degree-of-freedom adjustment and control step heat preservation cover, the temperature of the porous silicon carbide ceramic plate is increased; the three-linkage radial and axial cooperative regulation mechanism of electromagnetic heating, infrared compensation and dynamic heat preservation can be achieved, the temperature field uniformity in the growth process of the large-size silicon carbide crystals is improved, and the quality problems of defects, cracks and the like in the growth process of the crystals are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor material preparation, and particularly relates to a method and device for improving the uniformity of a large-size silicon carbide temperature field. BACKGROUND

[0002] Silicon carbide is a semiconductor material with excellent physical properties and is widely used in high-temperature, high-frequency and high-power electronic devices. In the growth process of large-size silicon carbide crystals, the uniformity of the temperature field plays a crucial role in the quality and performance of the crystals.

[0003] However, traditional silicon carbide crystal growth devices often have uneven temperature field distribution, which leads to quality problems such as defects and cracks in the growth process of the crystals, thereby affecting the application performance of the crystals. Therefore, how to improve the uniformity of the temperature field in the growth process of large-size silicon carbide crystals has become a difficult problem to be solved in the current technology. SUMMARY

[0004] The present application relates to the technical field of semiconductor material preparation, and particularly relates to a method and device for improving the uniformity of a large-size silicon carbide temperature field.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: A method for improving the uniformity of a large-size silicon carbide temperature field, comprising: Step one, real-time acquisition of axial and radial temperature data through a distributed sensor network; Step two, dynamic compensation of the temperature field using a multi-source collaborative heating system, independent adjustment of the partition power of the three-layer induction coil by ±15%, and simultaneous control of the output intensity of the MoSi2 infrared radiation plate; Step three, calculation of compensation parameters based on a thermal-electromagnetic coupling model; Step four, synchronous driving of a dynamic heat preservation structure, using a stepper motor to control the rotation of the rotating stepped heat preservation cover, and at the same time, starting the micro heat pipe.

[0006] Step five, temperature field simulation, judgment of thermal stress value (σ σ ), if σ ≤0.8 MPa, the growth is completed, otherwise, real-time acquisition of temperature field data using a sensor, and repeating steps one to five.

[0007] Preferably, the distributed sensor network in step one is composed of a bundle of silicon carbide fiber sensors and a lanthanum oxide coated thermocouple.

[0008] Preferably, the output power gradient intensity of the MoSi2 infrared radiation plate in step two is 0-5 kW / cm 2 and is adjustable.

[0009] Preferably, the rotating step cover in the fourth step is obliquely arranged, and the inclination angle and the rotating speed of the rotating step cover are 45-60 degrees and 5-15 rpm respectively.

[0010] The application discloses a device for improving the uniformity of a large-size silicon carbide temperature field. A furnace body; A composite heating subsystem is composed of three layers of induction coils, and the three layers of induction coils are coaxially arranged in the furnace body, and a MoSi2 infrared radiation plate integrated with a seed crystal holder is arranged below the three layers of induction coils, and the MoSi2 infrared radiation plate is fixedly installed in the furnace body. A gradient composite heat preservation structure is sequentially arranged from inside to outside as a heat reflection layer, a heat resistance layer and a heat dissipation regulation layer, and a step heat preservation cover is arranged at the outer periphery of the gradient composite heat preservation structure, a stepping motor is arranged above the step heat preservation cover and is used for driving the step heat preservation cover to rotate, and the stepping motor is fixedly installed at the inner top of the furnace body. An intelligent control unit is composed of an FPGA multivariable predictive controller and a porosity adjusting device. The three layers of induction coils are composed of three induction coils with different diameters, and the three induction coils are arranged at intervals from small to large and from high to low outside the step protection cover.

[0011] Preferably, the heat reflection layer, the heat resistance layer and the heat dissipation regulation layer are arranged between the three layers of induction coils and the MoSi2 infrared radiation plate, and the heat reflection layer and the heat resistance layer are respectively 0.1-0.3 mm molybdenum foil and carbon fiber felt.

[0012] Preferably, the heat dissipation regulation layer comprises a porous silicon carbide ceramic plate and a plurality of micro heat pipes, the porous silicon carbide ceramic plate is fixed at the bottom of the MoSi2 infrared radiation plate, and the plurality of micro heat pipes are arranged in an 8*8 grid shape at the bottom of the porous silicon carbide ceramic plate.

[0013] Preferably, the porosity adjusting device is a shape memory alloy actuator, which is used for continuously adjusting the porosity of the porous silicon carbide ceramic plate in a range of 30%-70%.

[0014] Compared with the prior art, the method and the device for improving the uniformity of a large-size silicon carbide temperature field have the following beneficial effects: 1. The three layers of induction coils with independently adjustable partition power by ±15% are arranged at the top of the furnace body, and the MoSi2 infrared radiation plate with a power of 0-5 kW / cm 2The power gradient output MoSi2 infrared radiation plate drives the porous silicon carbide ceramic plate by using the shape memory alloy, so that the porosity is continuously adjustable in the range of 30%-70%, and the step heat preservation cover capable of operating at the inclination angle of 45°-60° and the rotating speed of 5-15 rpm is controlled in two degrees of freedom, so that the radial and axial coordinated control mechanism of the three-linkage mechanism of electromagnetic heating-infrared compensation-dynamic heat preservation is realized, and the temperature field uniformity in the growth process of large-size silicon carbide crystals is improved, so that the quality problems such as defects and cracks of the crystals in the growth process are avoided.

[0015] 2、The distributed sensing network composed of the carbonized silicon fiber sensor bundle and the lanthanum oxide coating thermocouple, and the compensation parameter algorithm based on the thermal-electromagnetic coupling model calculation are matched, and the control of the FPGA multivariable predictive controller can improve the radial and axial coordinated control efficiency of the three-linkage mechanism of electromagnetic heating-infrared compensation-dynamic heat preservation. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A flowchart of a method for improving the temperature field uniformity of large-size silicon carbide is provided. Figure 2 A block diagram of the structure of a device for improving the temperature field uniformity of large-size silicon carbide is provided.

[0017] Figure 3 A three-dimensional structure diagram of a device for improving the temperature field uniformity of large-size silicon carbide is provided. Figure 4 A three-dimensional sectional structure diagram of a device for improving the temperature field uniformity of large-size silicon carbide is provided. Figure 5 A local three-dimensional structure diagram of a device for improving the temperature field uniformity of large-size silicon carbide is provided.

[0018] In the figure: 1 furnace body, 2 induction coil, 3 MoSi2 infrared radiation plate, 4 step heat preservation cover, 5 stepping motor, 6 driving motor, 7 porous silicon carbide ceramic plate, 8 micro heat pipe, 9 shape memory alloy actuator, 10 FPGA multivariable predictive controller. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all.

[0020] Embodiment 1: Reference Figure 1 A method for improving the temperature field uniformity of large-size silicon carbide, comprising: Step one, real-time acquisition of axial and radial temperature data by distributed sensor network, wherein the distributed sensor network is composed of a bundle of silicon carbide fiber sensors and lanthanum oxide coated thermocouples; Step two, dynamic compensation of temperature field by multi-source collaborative heating system, independent adjustment of partition power of three-layer induction coil, and simultaneous control of MoSi2 infrared radiation plate 3 output intensity; Step three, calculation of compensation parameters based on thermal-electromagnetic coupling model; Step four, synchronous driving of dynamic insulation structure, using stepper motor 5 to control the rotation of stepped insulation cover 4, and at the same time, starting the micro heat pipe 8.

[0021] Step five, temperature field simulation, judge thermal stress value (σ) σ ), if σ ≤0.8 MPa, complete growth, otherwise, use sensors to collect temperature field data in real time, repeat steps one to five.

[0022] Wherein, the parameters of dynamic adjustment are as follows:

[0023] Referring to Figures 2 to 5 , a device for improving the uniformity of large-size silicon carbide temperature field, comprising: Furnace body 1; composite heating subsystem: composed of three-layer induction coil, and the three-layer induction coil is coaxially arrayed in the furnace body 1, and a MoSi2 infrared radiation plate 3 integrated with a seed crystal holder is arranged below the three-layer induction coil, and the MoSi2 infrared radiation plate 3 is fixedly installed in the furnace body 1, and a heat reflection layer, a heat resistance layer and a heat dissipation control layer are arranged between the three-layer induction coil and the MoSi2 infrared radiation plate 3.

[0024] Gradient composite insulation structure: the heat reflection layer, the heat resistance layer and the heat dissipation control layer are arranged from inside to outside, and the heat reflection layer and the heat resistance layer are respectively 0.1mm molybdenum foil and carbon fiber felt, and the heat dissipation control layer includes a porous silicon carbide ceramic plate 7 and a plurality of micro heat pipes 8, the porous silicon carbide ceramic plate 7 is fixed at the bottom of the MoSi2 infrared radiation plate 3, and the plurality of micro heat pipes 8 are distributed in an 8x8 grid at the bottom of the porous silicon carbide ceramic plate 7; further comprising a stepped insulation cover 4 arranged on the outer periphery, the stepped insulation cover 4 is provided with a stepper motor 4 for driving the stepped insulation cover to rotate, and the stepper motor 4 is fixedly installed on the inner top of the furnace body, and the driving end surface of the stepper motor 4 is further fixedly installed with a driving motor 6 for driving the stepped insulation cover 4 to tilt.

[0025] Intelligent control unit: composed of FPGA multivariable predictive controller 10 and porosity adjusting device, the porosity adjusting device is shape memory alloy actuator 9, and the porosity of the porous silicon carbide ceramic plate 7 is adjusted to 40% by using the shape memory alloy actuator 9, and the low porosity can enhance the solid thermal conductivity and compensate the edge heat dissipation.

[0026] The three-layer induction coil is composed of three induction coils 2 with different diameters, and the three induction coils 2 are distributed at equal intervals from small to large and from high to low outside the stepped protective cover.

[0027] Example 2: Step one, real-time acquisition of axial and radial temperature data by distributed sensor network, wherein the distributed sensor network is composed of a bundle of silicon carbide fiber sensors and lanthanum oxide coated thermocouples; Step two, dynamic compensation of temperature field by using multi-source collaborative heating system, independent adjustment of partition power of three-layer induction coil, and control of MoSi2 infrared radiation plate 3 output intensity; Step three, calculation of compensation parameters based on thermal-electromagnetic coupling model; Step four, synchronous driving of dynamic insulation structure, using stepper motor 5 to control the rotation of stepped insulation cover 4, and at the same time, starting the micro heat pipe 8.

[0028] Step five, temperature field simulation, judge thermal stress value (σ) σ ), if σ ≤0.8 MPa, complete growth, otherwise, use sensors to collect temperature field data in real time, repeat steps one to five.

[0029] Wherein, the parameters of dynamic adjustment are as shown in the following table:

[0030] Referring to Figures 2 to 5 , a device for improving the uniformity of large-size silicon carbide temperature field, comprising: Furnace body; composite heating subsystem: composed of three-layer induction coil, and the three-layer induction coil is coaxially arrayed in the furnace body 1, and a MoSi2 infrared radiation plate 3 integrated with a seed crystal holder is arranged below the three-layer induction coil, and the MoSi2 infrared radiation plate 3 is fixedly installed in the furnace body 1, and a heat reflecting layer, a heat resisting layer and a heat dissipation regulating layer are arranged between the three-layer induction coil and the MoSi2 infrared radiation plate.

[0031] Gradient composite heat preservation structure: heat reflection layer, heat resistance layer and heat dissipation regulation layer are arranged in turn from inside to outside, and the heat reflection layer and the heat resistance layer are respectively 0.2mm molybdenum foil and carbon fiber felt, the heat dissipation regulation layer includes porous silicon carbide ceramic plate 7 and a plurality of micro heat pipes 8, the porous silicon carbide ceramic plate 7 is fixed at the bottom of the MoSi2 infrared radiation plate 3, and the plurality of micro heat pipes 8 are distributed in the bottom of the porous silicon carbide ceramic plate 7 in the form of 8*8 grid; it also includes the stepped heat preservation cover 4 arranged on the outer periphery, the stepped heat preservation cover 4 is provided with a stepping motor 5 for driving the stepped heat preservation cover 4 to rotate, and the stepping motor 5 is fixedly installed on the inner top of the furnace body 1.

[0032] Intelligent control unit: composed of FPGA multivariable predictive controller 10 and porosity adjusting device, the porosity adjusting device is shape memory alloy actuator 9, and the porosity of the porous silicon carbide ceramic plate 7 is adjusted to 50% by using the shape memory alloy actuator 9.

[0033] The three-layer induction coil is composed of three induction coils 2 with different diameters, and the three induction coils 2 are distributed at equal intervals from small to large and from high to low outside the stepped protection cover 4.

[0034] Example 3: Step one, real-time acquisition of axial and radial temperature data by distributed sensor network, wherein the distributed sensor network is composed of silicon carbide fiber sensor bundle and lanthanum oxide coating thermocouple; Step two, dynamic compensation of temperature field by using multi-source collaborative heating system, independent adjustment of partition power of three-layer induction coil, and control of MoSi2 infrared radiation plate 3 output intensity; Step three, calculation of compensation parameters based on thermal-electromagnetic coupling model; Step four, synchronous driving of dynamic heat preservation structure, using stepping motor 5 to control the rotation of stepped heat preservation cover 4, at the same time, starting micro heat pipe 8.

[0035] Step five, temperature field simulation, judge thermal stress value (σ) σ ), if σ ≤0.8 MPa, complete growth, otherwise, use sensors to collect temperature field data in real time, repeat steps one to five.

[0036] Wherein, the parameters of dynamic adjustment are as follows:

[0037] Referring to Figures 2 to 5 , a device for improving the uniformity of large-size silicon carbide temperature field, comprising: The furnace body 1; the composite heating subsystem: composed of three layers of induction coils, and the three layers of induction coils are coaxially arranged in the furnace body 1, and a MoSi2 infrared radiation plate 3 integrated with a seed crystal holder is arranged below the three layers of induction coils, and the MoSi2 infrared radiation plate 3 is fixedly installed in the furnace body, and a heat reflection layer, a heat resistance layer and a heat dissipation control layer are arranged between the three layers of induction coils and the MoSi2 infrared radiation plate.

[0038] The gradient composite heat preservation structure: the heat reflection layer, the heat resistance layer and the heat dissipation control layer are sequentially arranged from inside to outside, and the heat reflection layer and the heat resistance layer are respectively 0.3mm molybdenum foil and carbon fiber felt, the heat dissipation control layer includes a porous silicon carbide ceramic plate 7 and a plurality of micro heat pipes 8, the porous silicon carbide ceramic plate 7 is fixed at the bottom of the MoSi2 infrared radiation plate 3, the plurality of micro heat pipes 8 are distributed in the bottom of the porous silicon carbide ceramic plate 7 in the form of 8*8 grid, and the outer periphery of the gradient composite heat preservation structure is provided with a stepped heat preservation cover 4, the upper portion of the stepped heat preservation cover 4 is provided with a stepping motor 5 for driving the self-rotation of the stepped heat preservation cover 4, and the stepping motor 5 is fixedly installed at the inner top of the furnace body 1, and the driving end of the stepping motor 5 is also fixedly installed with a driving motor 7 for driving the inclination of the stepped heat preservation cover 4.

[0039] The intelligent control unit: composed of an FPGA multivariable predictive controller 10 and a porosity adjusting device, the porosity adjusting device is a shape memory alloy actuator 9, the porosity of the porous silicon carbide ceramic plate 7 is adjusted to 60% by using the shape memory alloy actuator 9, the high porosity (combining the micro heat pipe array, the three layers of induction coils are composed of three induction coils 2 with different diameters, and the three induction coils 2 are distributed at equal intervals outside the stepped protection cover 4 from small to large and from high to low.

[0040] Further, the above-mentioned fixed connection should be understood in a broad sense unless otherwise specified and limited, for example, it can be welding, or gluing, or integrally formed with other conventional means familiar to those skilled in the art.

[0041] The above-mentioned, only for the preferred specific embodiments of the present application, but the protection scope of the present application is not limited to this, any skilled in the art within the technical range disclosed by the present application, according to the technical scheme of the present application and the invention concept to make equivalent replacement or change, should be covered in the protection scope of the present application.

Claims

1. A method for improving the temperature field uniformity of large size silicon carbide, characterized in that, Comprising: Step one, real-time acquisition of axial and radial temperature data by distributed sensor network; Step two, dynamic compensation of temperature field by multi-source collaborative heating system, independent adjustment of partition power of three-layer induction coil ± 15%, and control of output intensity of MoSi2 infrared radiation plate (3); Step three, calculation of compensation parameters based on thermal-electromagnetic coupling model; Step four, synchronous driving of dynamic insulation structure, control of rotation of stepped insulation cover (4) by stepper motor (5), and start of micro heat pipe (8) at the same time. Step five, temperature field simulation is carried out to determine the thermal stress value The distributed sensor network in step one is composed of a bundle of silicon carbide fiber sensors and lanthanum oxide coated thermocouples. ), if The stepped insulation cover (4) in step four is arranged obliquely, and the inclination angle and rotation speed of the stepped insulation cover are 45°-60° and 5-15 rpm respectively. ≤0.8 MPa, the growth is completed, otherwise, the temperature field data is collected in real time by using the sensor, and steps one to five are repeated.

2. The method of claim 1, wherein, Comprising:

3. The method of claim 1, wherein, The output power gradient intensity of the MoSi2 infrared radiation plate (3) in the second step is 0-5 kW / cm 2 and adjustable.

4. The method of claim 1, wherein, Furnace body (1); 5. The device for improving the temperature field uniformity of large size silicon carbide according to any one of claims 1-4, characterized in that, Composite heating subsystem: composed of three-layer induction coil, and three-layer induction coil coaxial array distributed in the furnace body (1), MoSi2 infrared radiation plate (3) integrated by seed crystal holder below the three-layer induction coil (2), and MoSi2 infrared radiation plate (3) fixedly installed in the furnace body (1); Gradient composite insulation structure: heat reflecting layer, heat resisting layer and heat dissipation regulating layer arranged from inside to outside, and stepped insulation cover (4) arranged on the outer periphery, stepper motor (5) for driving self-rotation of the stepped insulation cover (4) above the stepped insulation cover (4), and stepper motor (5) fixedly installed on the inner top of the furnace body (1); Intelligent control unit: composed of FPGA multivariable predictive controller (10) and porosity adjusting device. The three-layer induction coil is composed of three induction coils (2) with different diameters, and the three induction coils (2) are distributed at equal intervals from small to large and from high to low outside the stepped protection cover (4). The heat reflecting layer, heat resisting layer and heat dissipation regulating layer are placed between the three-layer induction coil and the MoSi2 infrared radiation plate (3), and the heat reflecting layer and the heat resisting layer are respectively 0.1-0.3mm molybdenum foil and carbon fiber felt. The heat dissipation regulating layer includes a porous silicon carbide ceramic plate 7 and a plurality of micro heat pipes 8, the porous silicon carbide ceramic plate 7 is fixed at the bottom of the MoSi2 infrared radiation plate 3, and the plurality of micro heat pipes 8 are distributed in an 8×8 grid at the bottom of the porous silicon carbide ceramic plate (7).

6. The device for improving the uniformity of the temperature field of large-size silicon carbide according to claim 5, characterized in that, The porosity adjusting device is a shape memory alloy actuator (9) for continuously adjusting the porosity of the porous silicon carbide ceramic plate (7) in the range of 30%-70%.

7. The device for improving the uniformity of the temperature field of large-size silicon carbide according to claim 5, characterized in that, ​ 8. The device for improving the temperature field uniformity of large-size silicon carbide according to claim 5, characterized in that, ​

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