Air inlet uniformizing device

Abstract

The application relates to the technical field of epitaxial equipment, and discloses an air inlet uniformizing device which comprises an air inlet pipe group, a gas mixing cylinder and a uniformizing air guide box; the air inlet pipe group comprises a plurality of air inlet pipes which are communicated into the gas mixing cylinder, the air inlet pipes extend to the outlet direction of the gas mixing cylinder, each air inlet pipe comprises an air outlet section, the air outlet section is located in the gas mixing cylinder, the air outlet section is in a spiral shape, and a plurality of first air outlet holes are arranged on each air outlet section; the outlet end of the gas mixing cylinder is communicated with the inlet end of the uniformizing air guide box, a gas flow channel is arranged in the uniformizing air guide box, and the outlet of the uniformizing air guide box is used for being communicated with a reaction chamber. The gas required by the reaction enters the gas mixing cylinder through the first air outlet holes on the air inlet pipes, is fully mixed, and then is guided to flow through the uniformizing air guide box, so that the gas concentration distribution on the substrate surface in the reaction chamber is uniform, the gas flow of each part is consistent, and the consistency and reliability of an epitaxial layer obtained through the reaction are improved.

Description

Technical Field

[0001] This invention relates to the field of epitaxial equipment technology, and in particular to an air intake and equalization device. Background Technology

[0002] Silicon carbide (SiC), as a third-generation wide-bandgap semiconductor material, possesses excellent high-temperature resistance, high-voltage resistance, and high-frequency characteristics, and is widely used in new energy vehicles, photovoltaics, communications, and other fields. Epitaxial growth is the core process in SiC device fabrication. This process involves introducing carbon and silicon source gases (such as SiH4 and C2H2) along with a carrier gas (such as H2) into a reaction chamber, where a chemical reaction occurs on the surface of a high-temperature substrate, depositing and forming a SiC thin film epitaxial layer.

[0003] In current silicon carbide epitaxial equipment, the gas homogenization device usually adopts a single-stage porous plate or a simple flow guiding structure. These designs have significant technical defects. For example, the mixing time between the source gas and the carrier gas before entering the reaction chamber is insufficient, resulting in low mixing efficiency and uneven gas concentration distribution on the substrate surface. This leads to large deviations in epitaxial layer thickness, affecting the consistency and reliability of the device. In addition, although the simple flow guiding structure can guide the gas flow to a certain extent, the gas flow rate in the middle is often greater than that at the edge, causing abnormal growth rate of the epitaxial layer at the substrate edge, resulting in edge thickening or thinning, reducing the yield of epitaxial wafers and affecting device performance. Summary of the Invention

[0004] The present invention aims to improve at least one technical problem in the prior art.

[0005] This invention proposes an inlet gas equalization device, which achieves consistency in the mixing ratio of reaction gases and uniformity of airflow through a multi-layer mixing diffusion and graded gas equalization and guiding structure design, thereby ensuring the uniformity of epitaxial process and device performance.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: it is an air intake and equalization device, including an air intake pipe assembly, a gas mixing cylinder, and an equalization guide box.

[0007] The intake pipe assembly includes several intake pipes connected to the gas mixing cylinder. The intake pipes extend toward the outlet of the gas mixing cylinder. Each intake pipe includes an exhaust section located inside the gas mixing cylinder. The exhaust section is spiral-shaped and each exhaust section is provided with multiple first exhaust holes.

[0008] The outlet end of the gas mixing cylinder is connected to the inlet end of the gas equalization guide box. The gas equalization guide box is provided with a gas flow channel. The outlet of the gas equalization guide box is used to connect with the reaction chamber. The gas passes through the gas mixing cylinder and the gas equalization guide box in sequence from the gas inlet pipe group, and then enters the reaction chamber.

[0009] As a further improvement to the above technical solution, the outer surface of the gas mixing cylinder is provided with a heating element group.

[0010] As a further improvement to the above technical solution, the heating element group includes a first heating element and a second heating element, which are alternately arranged. The first heating element is in the shape of a ring and has a first notch to make it open-ring. The second heating element is in the shape of a ring and has a second notch to make it open-ring. The first notch and the second notch face opposite directions.

[0011] As a further improvement to the above technical solution, the gas mixing cylinder also includes a gas collecting nozzle, which is located at the outlet end of the gas mixing cylinder. The inlet end of the gas collecting nozzle is circular, and the outlet end of the gas collecting nozzle is rectangular. The outlet end of the gas collecting nozzle is connected to the inlet end of the gas equalization guide box, and the gas in the gas mixing cylinder enters the gas equalization guide box through the gas collecting nozzle.

[0012] As a further improvement to the above technical solution, the gas flow guide box includes a variable diameter box, the inlet end of which is connected to the outlet end of the gas mixing cylinder, and the outlet end of which is connected to the reaction chamber. The lateral length of the variable diameter box gradually increases from the inlet end to the outlet end.

[0013] As a further improvement to the above technical solution, the difference between the lateral length of the outlet end of the variable diameter box and the wafer diameter is greater than 50mm.

[0014] As a further improvement to the above technical solution, the gas equalization and flow guiding box further includes a flow guiding plate, a driver, and a pressure sensor. There are two flow guiding plates and two drivers. The driver is provided with a rotating shaft, which vertically passes through the bottom surface of the gas equalization and flow guiding box. The flow guiding plate is located inside the variable diameter box and is fixedly connected to the rotating shaft. The flow guiding plate laterally divides the variable diameter box into a first gas flow channel, a second gas flow channel, and a third gas flow channel. The first gas flow channel, the second gas flow channel, and the third gas flow channel are all directly connected to the gas mixing cylinder and the reaction chamber. The pressure sensor is provided on the flow guiding plate and is used to monitor the gas pressure difference on both sides of the flow guiding plate. The driver is used to drive the flow guiding plate to rotate around the rotating shaft.

[0015] As a further improvement to the above technical solution, the gas equalization guide box also includes a gas equalization plate, which is located at the outlet end of the gas equalization guide box. The gas in the gas equalization guide box enters the reaction chamber through the gas equalization plate. The gas equalization plate is provided with a plurality of second exhaust holes, and the diameter of the outlet end of the second exhaust holes increases sequentially.

[0016] As a further improvement to the above technical solution, the air intake and equalization device also includes a flow guide shroud, the inlet end of which is connected to the outlet end of the equalization plate, and the vertical height on both sides of the inlet end of the flow guide shroud is greater than the vertical height in the middle.

[0017] As a further improvement to the above technical solution, the distance between the fixed position of each air intake pipe and the central axis of the gas mixing cylinder is 60mm, and / or each air intake pipe is equipped with a flow controller, and / or the number of spiral turns of the exhaust section is 3-5, and / or the pitch of the exhaust section is 80-100mm, and / or the diameter of the first exhaust hole is 3-5mm.

[0018] The technical solution has at least the following beneficial effects: the gas required for the reaction enters the gas mixing cylinder from the exhaust section of the inlet pipe. The spiral shape and the design of multiple first exhaust holes are conducive to improving the gas mixing efficiency and the uniform gas flow. Then, the gas flow is guided by the uniform gas flow guide box, which is conducive to the uniform distribution of gas concentration on the substrate surface in the reaction chamber and the consistent gas flow in each part, thereby improving the consistency and reliability of the epitaxial layer obtained by the reaction. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the air intake and equalization device of the present invention;

[0021] Figure 2 This is a side view of an embodiment of the air intake and equalization device of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of an embodiment of the intake pipe of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of an embodiment of the gas distribution and flow guiding box of the present invention;

[0024] Figure 5 This is a schematic diagram illustrating the function of the air distribution plate in an embodiment of the present invention;

[0025] Figure 6 This is a cross-sectional view of an embodiment of the gas distribution and flow guiding box of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of an embodiment of the gas distribution and flow guiding box of the present invention.

[0027] In the attached diagram: 1-Inlet pipe assembly; 11-Exhaust section; 110-First exhaust port; 2-Gas mixing cylinder; 21-Heating plate assembly; 22-Gas collecting nozzle; 3-Gas distribution guide box; 31-Variable diameter box; 32-Guide plate; 33-Driver; 331-Rotating shaft; 34-Gas distribution plate; 340-Second exhaust port; 35-Guide shroud; 4-Reaction chamber. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] The following is combined with Figures 1 to 7 Embodiments of the present invention will be described.

[0030] Reference Figure 1 An air intake and equalization device in this embodiment includes an air intake pipe assembly 1, a gas mixing cylinder 2, and an equalization guide box 3.

[0031] The intake pipe assembly 1 includes a plurality of intake pipes connected to the gas mixing cylinder 2. The intake pipes extend toward the outlet direction of the gas mixing cylinder 2. Each intake pipe includes an exhaust section 11. The exhaust section 11 is located inside the gas mixing cylinder 2. The exhaust section 11 is spiral in shape. Each exhaust section 11 is provided with a plurality of first exhaust holes 110.

[0032] The outlet end of the gas mixing cylinder 2 is connected to the inlet end of the gas equalization guide box 3. The gas equalization guide box 3 is provided with a gas flow channel. The outlet of the gas equalization guide box 3 is used to connect with the reaction chamber 4. The gas passes through the gas mixing cylinder 2 and the gas equalization guide box 3 in sequence from the gas inlet pipe group 1, and then enters the reaction chamber 4.

[0033] In current silicon carbide epitaxial equipment, the gas homogenizing device typically employs a single-stage porous plate or a simple flow guiding structure. These designs have significant technical drawbacks. For example, insufficient mixing time between the source gas and carrier gas before entering the reaction chamber leads to low mixing efficiency and uneven gas concentration distribution on the substrate surface, resulting in large deviations in epitaxial layer thickness and affecting device consistency and reliability. In this embodiment, the gas required for the reaction enters the gas mixing cylinder 2 from the exhaust section 11 of the inlet pipe. The spiral shape and multiple first exhaust holes 110 design improve gas mixing efficiency and enhance gas homogenization. Then, the gas flow is guided by the gas homogenizing guide box 3, which helps to ensure uniform gas concentration distribution on the substrate surface within the reaction chamber 4 and consistent gas flow rates in each part, thereby improving the consistency and reliability of the epitaxial layer obtained from the reaction. Specifically, the inlet pipe assembly 1 can be composed of several inlet pipes for conveying gases such as SiH4, CH4, and H2. The inlet pipe assembly 1 is installed with the gas mixing cylinder 2, and a sealing sleeve is used to ensure the sealing of the connection. The outlet end of the gas mixing cylinder 2 is installed in conjunction with the inlet end of the gas equalization guide box 3. The outlet end of the gas equalization guide box 3 is used to be installed on the reaction chamber 4, and the height of the gas equalization guide box 3 is adapted to the height of the substrate.

[0034] Reference Figure 1 In some embodiments, the outer surface of the gas mixing cylinder 2 is provided with a heating element group 21. By providing the heating element group 21, the mixed gas is preheated, avoiding temperature fluctuations caused by low-temperature gas entering the reaction chamber 4, improving the stability of gas entering the reaction chamber 4, and ensuring the uniformity of airflow.

[0035] In some embodiments, the heating element group 21 includes a first heating element and a second heating element, which are alternately arranged. The first heating element is annular and has a first notch to make it an open ring. The second heating element is annular and has a second notch to make it an open ring. The first and second notches face opposite directions. The surface of the mixing cylinder is covered with alternately arranged first and second heating elements, which are staggered to improve the preheating effect of the mixed gas, avoid temperature fluctuations caused by low-temperature gas entering the reaction chamber 4, improve the stability of gas entering the reaction chamber 4, and ensure the uniformity of gas flow.

[0036] Reference Figure 1In some embodiments, the gas mixing cylinder 2 further includes a gas collecting nozzle 22 located at the outlet end of the gas mixing cylinder 2. The inlet end of the gas collecting nozzle 22 is circular, and the outlet end is rectangular. The outlet end of the gas collecting nozzle 22 is connected to the inlet end of the gas equalization and diversion box 3, and the gas in the gas mixing cylinder 2 enters the gas equalization and diversion box 3 through the gas collecting nozzle 22. The inlet end of the gas collecting nozzle 22 is circular, the outlet end is rectangular, and the middle part is a gradual transition from circular to rectangular, which facilitates the uniform entry of gas from the gas mixing cylinder 2 into the gas equalization and diversion box 3.

[0037] Reference Figure 4 In some embodiments, the gas flow guide box 3 includes a variable diameter box 31. The inlet end of the variable diameter box 31 is connected to the outlet end of the gas mixing cylinder 2, and the outlet end of the variable diameter box 31 is connected to the reaction chamber 4. The lateral length of the variable diameter box 31 gradually increases from the inlet end to the outlet end. Specifically, one end of the variable diameter box 31 has a small rectangular diameter, which is adapted to the outlet end of the gas mixing cylinder 2. When a gas collecting nozzle 22 is provided at the outlet end of the gas mixing cylinder 2, the variable diameter box 31 is adapted to the outlet end of the gas collecting nozzle 22. The other end has a large rectangular diameter, which is adapted to the interface of the reaction chamber 4. The variable diameter box 31 helps to guide the gas flow and improve the uniformity of the airflow.

[0038] In some embodiments, the difference between the lateral length of the outlet end of the variable diameter box 31 and the wafer diameter is greater than 50 mm. This arrangement ensures that the process gas can cover the entire wafer surface, improving the uniformity of the epitaxial process and device performance.

[0039] Reference Figure 4 and Figure 5 In some embodiments, the gas equalization and flow guiding box 3 further includes a flow guiding plate 32, a driver 33, and a pressure sensor. There are two flow guiding plates 32 and two drivers 33. The driver 33 is provided with a rotating shaft 331, which vertically penetrates the bottom surface of the gas equalization and flow guiding box 3. The flow guiding plate 32 is located inside the variable diameter box 31 and is fixedly connected to the rotating shaft 331. The flow guiding plate 32 laterally divides the variable diameter box 31 into a first gas flow channel, a second gas flow channel, and a third gas flow channel. The first gas flow channel, the second gas flow channel, and the third gas flow channel are all directly connected to the gas mixing cylinder 2 and the reaction chamber 4. The pressure sensor is provided on the flow guiding plate 32. The pressure sensor is used to monitor the gas pressure difference on both sides of the flow guiding plate 32. The driver 33 is used to drive the flow guiding plate 32 to rotate around the rotating shaft 331. Figure 5Figures A and B illustrate one embodiment of the rotating guide vanes. In the prior art, although simple guide structures can guide gas flow to a certain extent, the gas flow rate in the middle is often greater than that at the edge, causing abnormal growth rates of the epitaxial layer at the substrate edge, resulting in edge thickening or thinning, reducing the yield of the epitaxial wafer, and affecting device performance. The structure of this embodiment facilitates real-time adjustment of the gas flow rate in the three gas channels, ensuring gas supply or compensation in the middle and edge of the wafer, and promoting uniform gas concentration distribution on the substrate surface within the reaction chamber 4. Specifically, the driver 33 can use a rotating motor, a rotating cylinder, or a gear transmission structure, etc. The two guide vanes 32 are installed in the variable diameter box 31 via a rotating shaft 331 fixed to the driver 33, dividing the variable diameter box 31 into three parts: the first gas channel, the second gas channel, and the third gas channel, corresponding to the positions of the middle and edge of the wafer within the reaction chamber 4, respectively. Pressure sensors are mounted on the guide vanes 32, and by detecting the gas pressure difference between the left, middle, and right sides of the variable diameter box 31, the rotating motor can be controlled to drive the guide vanes 32 to rotate. Two miniature pressure sensors can be installed on each guide vane 32 to measure the gas pressure on both sides and then calculate the pressure difference. Alternatively, a miniature differential pressure sensor can be used to obtain the gas pressure difference on both sides of the guide vane 32.

[0040] Reference Figure 4 and Figure 6 In some embodiments, the gas distribution box 3 further includes a gas distribution plate 34, which is located at the outlet end of the gas distribution box 3. The gas in the gas distribution box 3 enters the reaction chamber 4 through the gas distribution plate 34. The gas distribution plate 34 is provided with a plurality of second exhaust holes 340, and the diameter of the outlet end of the second exhaust holes 340 increases sequentially. The structure of the second exhaust holes 340 in this embodiment allows the gas to enter the reaction chamber 4 radially, further improving the uniformity of the airflow. Specifically, the gas distribution plate 34 can be provided with 3-5 rows of second exhaust holes 340, and the diameter of the outlet end of the second exhaust holes 340 increases sequentially, that is, each exhaust hole is composed of a cylindrical front half and a frustum rear half.

[0041] Reference Figure 4 and Figure 7 In some embodiments, the gas inlet and gas distribution device further includes a flow guide hood 35, the inlet end of which is connected to the outlet end of the gas distribution plate 34. The vertical height on both sides of the inlet end of the flow guide hood 35 is greater than the vertical height in the middle. The gas inlet hood is installed on the gas distribution plate 34, and the process gas is introduced into the reaction chamber 4. The gas inlet of the flow guide hood 35 is smaller in the middle and larger on both sides to ensure edge gas compensation and flow velocity uniformity.

[0042] Reference Figure 2 and Figure 3In some embodiments, the distance between the fixed position of each intake pipe and the central axis of the gas mixing cylinder 2 is 60mm, and / or each intake pipe is equipped with a flow controller, and / or the number of spiral turns of the exhaust section 11 is 3-5, and / or the pitch of the exhaust section 11 is 80-100mm, and / or the diameter of the first exhaust hole 110 is 3-5mm. The above are preferred structural configurations of the exhaust section 11, which can improve gas mixing efficiency. Specifically, the flow controller can be located at the intake end of the intake pipe, outside the gas mixing cylinder 2. The selection of the above specific parameters is only a preferred range, and the parameters do not affect each other.

[0043] The preferred embodiments of the present invention have been described in detail above, but the present disclosure is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present disclosure.

[0044] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0045] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

Claims

1. An air intake and equalization device, characterized in that: It includes an intake pipe assembly (1), a gas mixing cylinder (2), and a gas distribution guide box (3); The intake pipe assembly (1) includes several intake pipes connected to the gas mixing cylinder (2). The intake pipes extend toward the outlet direction of the gas mixing cylinder (2). Each intake pipe includes an exhaust section (11). The exhaust section (11) is located inside the gas mixing cylinder (2). The exhaust section (11) is spiral in shape. Each exhaust section (11) is provided with a plurality of first exhaust holes (110). The outlet end of the gas mixing cylinder (2) is connected to the inlet end of the gas equalization guide box (3). The gas equalization guide box (3) is provided with a gas flow channel. The outlet of the gas equalization guide box (3) is connected to the reaction chamber (4). The gas passes through the gas mixing cylinder (2) and the gas equalization guide box (3) in sequence from the gas inlet pipe group (1) and then enters the reaction chamber (4). The gas flow guide box (3) includes a variable diameter box (31). The inlet end of the variable diameter box (31) is connected to the outlet end of the gas mixing cylinder (2). The outlet end of the variable diameter box (31) is connected to the reaction chamber (4). The transverse length of the variable diameter box (31) gradually increases from the inlet end to the outlet end. The gas distribution box (3) further includes a guide vane (32), a driver (33), and a pressure sensor. There are two guide vanes (32) and two drivers (33). The driver (33) has a rotating shaft (331) that vertically penetrates the bottom surface of the gas distribution box (3). The guide vane (32) is located inside the variable diameter box (31) and is fixedly connected to the rotating shaft (331). The guide vane (32) directs the flow of the variable diameter box... The diaphragm box (31) is laterally divided into a first gas flow channel, a second gas flow channel and a third gas flow channel. The first gas flow channel, the second gas flow channel and the third gas flow channel are all directly connected to the gas mixing cylinder (2) and the reaction chamber (4). The pressure sensor is provided on the guide plate (32). The pressure sensor is used to monitor the gas pressure difference on both sides of the guide plate (32). The driver (33) is used to drive the guide plate (32) to rotate around the rotating shaft (331).

2. The air intake and equalization device according to claim 1, characterized in that: The outer surface of the gas mixing cylinder (2) is provided with a heating element group (21).

3. The air intake and equalization device according to claim 2, characterized in that: The heating element group (21) includes a first heating element and a second heating element, which are alternately arranged. The first heating element is in the shape of a ring and has a first notch to make it open-ring. The second heating element is in the shape of a ring and has a second notch to make it open-ring. The first notch and the second notch face opposite directions.

4. The air intake and equalization device according to claim 1, characterized in that: The gas mixing cylinder (2) also includes a gas collecting nozzle (22), which is located at the outlet end of the gas mixing cylinder (2). The inlet end of the gas collecting nozzle (22) is circular, and the outlet end of the gas collecting nozzle (22) is rectangular. The outlet end of the gas collecting nozzle (22) is connected to the inlet end of the gas equalization guide box (3). The gas in the gas mixing cylinder (2) enters the gas equalization guide box (3) through the gas collecting nozzle (22).

5. The air intake and equalization device according to claim 1, characterized in that: The difference between the lateral length of the outlet end of the variable diameter box (31) and the wafer diameter is greater than 50 mm.

6. The air intake and equalization device according to claim 1, characterized in that: The gas distribution box (3) also includes a gas distribution plate (34), which is located at the outlet end of the gas distribution box (3). The gas in the gas distribution box (3) enters the reaction chamber (4) through the gas distribution plate (34). The gas distribution plate (34) is provided with a plurality of second exhaust holes (340), and the diameter of the outlet end of the second exhaust hole (340) increases sequentially.

7. The air intake and equalization device according to claim 6, characterized in that: The air intake equalization device also includes a flow guide hood (35), the inlet end of which is connected to the outlet end of the equalization plate (34), and the vertical height on both sides of the inlet end of the flow guide hood (35) is greater than the vertical height in the middle.

8. The air intake and equalization device according to claim 1, characterized in that: The distance between the fixed position of each of the air intake pipes and the central axis of the gas mixing cylinder (2) is 60 mm, and / or each of the air intake pipes is provided with a flow controller, and / or the number of spiral turns of the exhaust section (11) is 3-5, and / or the pitch of the exhaust section (11) is 80-100 mm, and / or the diameter of the first exhaust hole (110) is 3-5 mm.

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