A heat shield and a vertical high-temperature oxidation furnace comprising the same

Abstract

The utility model discloses a heat shield and vertical high temperature oxidation furnace containing it, a plurality of first through -hole are evenly distributed to the outside of heat shield, the first through -hole is used for realizing heat shield penetration installation, the front of heat shield is smooth surface, and the back of heat shield is equipped with sunken platform and a plurality of flow guide grooves, the sunken platform is located the central position, one end of flow guide groove communicates with the sunken platform, and the other end of flow guide groove extends to the outer edge of heat shield, and flow guide groove and first through -hole mutually avoid, the sunken platform is used for fixed air inlet component, and flow guide groove is used for realizing that gas diffuses evenly along the back of heat shield. The utility model has compact structure, convenient to dismount and is favorable to the characteristics such as the improvement of gas distribution uniformity, make the atmosphere in vertical high temperature oxidation furnace more uniform, improve the uniformity of wafer heating, solve the problem that the oxidation film thickness uniformity of wafer in the existing silicon carbide high temperature oxidation furnace is insufficient, and it is favorable to large -scale commercial production application.

Description

Technical Field

[0001] This utility model relates to the field of third-generation semiconductor equipment and process technology, specifically to a heat insulation screen and a vertical high-temperature oxidation furnace containing the screen. Background Technology

[0002] In the manufacturing process of SiC chips and transistors, the surface of SiC wafers needs to be oxidized to form a SiO2 oxide layer. The SiC high-temperature oxidation furnace is a key process equipment specifically used for SiC gate oxide layer preparation, directly affecting the quality of the oxide layer on the SiC wafer surface, such as film thickness uniformity, and further impacting the stability and reliability of SiC devices. Inside the SiC high-temperature oxidation furnace, a perforated heat shield is typically used for bottom insulation and to maintain temperature uniformity throughout the constant-temperature zone, ensuring that all wafers are oxidized at a consistent or similar temperature, thereby achieving high film thickness uniformity. However, existing heat shields all have a circular through-hole in the center for air intake. Because the intake air temperature is low and blows directly onto the bottom wafers, the temperature of some wafers at the bottom of the oxidation furnace is relatively low, further resulting in thinner oxide layers on some wafers. Utility Model Content

[0003] The technical problem to be solved by this utility model is that the existing central through-hole heat insulation screen has a low inlet temperature and blows directly onto the bottom wafer, resulting in a relatively low temperature of the bottom wafer and a thinner oxide layer film thickness, which leads to insufficient uniformity of oxide layer film thickness. The present invention provides a heat insulation screen with a compact structure, convenient disassembly and assembly, and which is conducive to improving the uniformity of gas distribution, as well as a vertical high-temperature oxidation furnace containing the present invention.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A heat insulation screen has multiple first through holes evenly distributed on its outer side. The first through holes are used to allow the heat insulation screen to be installed through the screen. The front of the heat insulation screen is a smooth surface, and the back of the heat insulation screen is provided with a recessed platform and multiple guide grooves. The recessed platform is located at the center position. One end of each guide groove is connected to the recessed platform, and the other end of each guide groove extends to the outer edge of the heat insulation screen. The guide grooves avoid each other from the first through holes. The recessed platform is used to fix the air intake component, and the guide grooves are used to allow the gas to diffuse evenly along the back of the heat insulation screen.

[0005] As a further improvement of this utility model, multiple guide channels are arranged at equal intervals on the back of the heat insulation screen.

[0006] As a further improvement of this utility model, the guide groove is an arc-shaped groove.

[0007] As a further improvement of this utility model, the depth of the guide groove is 1 / 3 to 1 / 2 of the thickness of the heat insulation screen.

[0008] As a further improvement of this utility model, the radius of curvature of the guide channel is 130~150mm, the depth of the guide channel is 2~3mm, and the width of the guide channel is 1~3mm.

[0009] As a further improvement of this utility model, the heat insulation screen is made of silicon carbide.

[0010] As a general technical concept, this utility model also provides a vertical high-temperature oxidation furnace. The furnace body is provided with a boat frame, heat insulation plates, an air inlet pipe, and the aforementioned heat insulation screen. The boat frame is used to place wafers. The bottom of the boat frame is connected to the heat insulation screen. Multiple heat insulation plates are stacked vertically below the heat insulation screen. The air inlet pipe passes through the central hole of the heat insulation plate and is nested in the sink, so as to realize that the heating gas is evenly diffused into the furnace body through the guide groove.

[0011] As a further improvement of this utility model, a support column is provided between the boat frame and the heat insulation screen, and the support column penetrates the first through hole.

[0012] As a further improvement of this utility model, a gasket is provided between two adjacent heat insulation boards.

[0013] As a further improvement of this utility model, the heat insulation plate is provided with a plurality of second through holes on its outer side, and the second through holes are used to realize the heat insulation plate through installation.

[0014] Compared with the prior art, the advantages of this utility model are: This invention relates to a heat insulation screen and a vertical high-temperature oxidation furnace containing it. By setting a platform and a guide channel on the back of the heat insulation screen, with one end of the guide channel connected to the platform and the other end extending to the outer edge of the heat insulation screen, it not only provides air intake but also prevents the air intake from directly blowing onto the wafers at the bottom of the furnace, significantly improving the uniformity of the oxide layer thickness on the SiC wafer surface. Furthermore, because the heat insulation screen has a high temperature, the guide channel can preheat the gas, effectively increasing the intake temperature. Simultaneously, the arc-shaped guide channel changes the air intake direction, making the atmosphere in the reaction chamber of the vertical high-temperature oxidation furnace more uniform. This invention effectively solves the problem of insufficient oxide layer thickness uniformity on wafers in existing silicon carbide high-temperature oxidation furnaces, which is beneficial for large-scale commercial production applications. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structural principle of a vertical high-temperature oxidation furnace in a specific embodiment of this utility model; Figure 2 This is a schematic diagram of the structural principle of the heat insulation screen in a specific embodiment of the present utility model; wherein, Figure (a) is the front of the heat insulation screen and Figure (b) is the back of the heat insulation screen; Figure 3This is a schematic diagram of the structural principle of the heat insulation plate in a specific embodiment of this utility model; Legend: 1. Boat frame support; 2. Wafer; 3. Boat frame base plate; 4. Support column; 5. Heat shield; 6. Heat shield plate; 7. Gasket; 8. Air inlet pipe; 51. First through hole; 52. Guide groove; 53. Recessed platform; 61. Second through hole; 62. Center hole. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0017] In the description of this utility model, it should be understood that the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0019] Example like Figure 2 As shown, the heat insulation screen 5 of this utility model is generally circular in shape. Three first through holes 51 are evenly spaced on the outer side of the heat insulation screen 5, allowing for through-hole installation. The front of the heat insulation screen 5 is smooth, while the back of the heat insulation screen 5 has a recessed platform 53 and multiple guide grooves 52 arranged with equal depth, width, and spacing. The recessed platform 53 is located at the center. One end of each guide groove 52 communicates with the recessed platform 53, and the other end extends to the outer edge of the heat insulation screen 5. The guide grooves 52 and the first through holes 51 avoid each other to prevent gas from diffusing through the first through holes 51 and reducing the uniformity of gas distribution. The recessed platform 53 is used to fix the air intake component, and the guide grooves 52 are used to achieve uniform gas diffusion along the back of the heat insulation screen 5.

[0020] In this embodiment, the guide groove 52 is an arc-shaped groove, and the depth of the guide groove 52 is 1 / 3 to 1 / 2 of the thickness of the heat insulation screen 5, so as to improve the uniformity of gas diffusion.

[0021] Furthermore, the radius of curvature of the guide channel 52 is 130~150mm, the depth of the guide channel 52 is 2~3mm, and the width of the guide channel 52 is 1~3mm.

[0022] like Figure 1 As shown, this embodiment also provides a vertical high-temperature oxidation furnace. The furnace body includes a boat frame consisting of a boat frame support 1 and a boat frame base plate 3, as well as a heat shield 5, heat insulation plates 6, and an inlet pipe 8. A wafer 2 is placed on the boat frame support 1. The bottom of the boat frame base plate 3 is connected to the heat shield 5. Multiple heat insulation plates 6 are stacked vertically below the heat shield 5. The bottom of the inlet pipe 8 is connected to an external gas source, and the top of the inlet pipe 8 passes through the central hole 62 of the heat insulation plate 6 and is nested within a recessed platform 53. The diameter of the recessed platform 53 is slightly larger than the diameter of the inlet pipe 8. The inlet pipe 8 does not directly contact the surface of the heat shield 5, allowing gas to enter the recessed platform 53 and diffuse out through the guide channel 52. By thickening the traditional heat shield and designing a circular recessed platform 53 and an arc-shaped guide channel 52 on its back, the recessed platform 53 is nested with the inlet pipe 8, allowing gas to enter the guide channel 52 and exit, resulting in uniform diffusion throughout the furnace body. Both the heat insulation screen 5 and the heat insulation board 6 are made of high-purity silicon carbide and have excellent high-temperature resistance.

[0023] In this embodiment, since the heat insulation screen 5 has a high temperature, the guide groove 52 can preheat the gas to a certain extent, effectively increasing the temperature of the incoming gas. At the same time, the arc-shaped guide groove 52 changes the direction of the incoming gas, making the atmosphere in the reaction chamber of the vertical high-temperature oxidation furnace more uniform, and significantly improving the uniformity of the oxide layer thickness on the SiC wafer surface.

[0024] like Figure 1 As shown, a support column 4 is provided between the boat frame and the heat insulation screen 5, and the support column 4 penetrates the first through hole 51.

[0025] like Figure 1 As shown, a gasket 7 is provided between two adjacent heat insulation boards 6 to improve the stability of the heat insulation board 6 installation.

[0026] like Figure 3 As shown, the heat insulation plate 6 has multiple second through holes 61 on its outer side, which are used to allow the heat insulation plate 6 to be installed through.

[0027] In this embodiment, by setting a recessed platform 53 and a guide channel 52 on the back of the heat insulation screen 5, with one end of the guide channel 52 connected to the recessed platform 53 and the other end extending to the outer edge of the heat insulation screen 5, it not only has an air intake function but also avoids the air intake blowing directly onto the wafer 2 at the bottom of the furnace body, which significantly improves the uniformity of the oxide layer thickness on the SiC wafer surface.

[0028] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected by this utility model. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A heat insulation screen, characterized in that, Multiple first through holes (51) are evenly distributed on the outer side of the heat insulation screen (5). The first through holes (51) are used to realize the heat insulation screen (5) through installation. The front of the heat insulation screen (5) is a smooth surface. The back of the heat insulation screen (5) is provided with a recessed platform (53) and multiple guide grooves (52). The recessed platform (53) is located in the center position. One end of the guide groove (52) is connected to the recessed platform (53). The other end of the guide groove (52) extends to the outer edge of the heat insulation screen (5). The guide groove (52) avoids the first through holes (51). The recessed platform (53) is used to fix the air intake component. The guide groove (52) is used to realize the uniform diffusion of gas along the back of the heat insulation screen (5).

2. The heat insulation screen according to claim 1, characterized in that, Multiple guide channels (52) are arranged at equal intervals on the back of the heat insulation screen (5).

3. The heat insulation screen according to claim 2, characterized in that, The guide groove (52) is an arc-shaped groove.

4. The heat insulation screen according to claim 2, characterized in that, The depth of the guide groove (52) is 1 / 3 to 1 / 2 of the thickness of the heat insulation screen (5).

5. The heat insulation screen according to claim 2, characterized in that, The radius of curvature of the guide groove (52) is 130~150mm, the depth of the guide groove (52) is 2~3mm, and the width of the guide groove (52) is 1~3mm.

6. The heat insulation screen according to any one of claims 1 to 5, characterized in that, The heat insulation screen (5) is made of silicon carbide.

7. A vertical high-temperature oxidation furnace, characterized in that, The vertical high-temperature oxidation furnace is equipped with a boat frame, a heat insulation plate (6), an air inlet pipe (8), and a heat insulation screen (5) as described in any one of claims 1 to 6. The boat frame is used to place the wafer (2). The bottom of the boat frame is connected to the heat insulation screen (5). Multiple heat insulation plates (6) are stacked vertically below the heat insulation screen (5). The air inlet pipe (8) passes through the central hole (62) of the heat insulation plate (6) and is nested in the sink (53) so that the heating gas can be evenly diffused into the furnace body through the guide groove (52).

8. The vertical high-temperature oxidation furnace according to claim 7, characterized in that, A support column (4) is provided between the boat frame and the heat insulation screen (5), and the support column (4) penetrates the first through hole (51).

9. The vertical high-temperature oxidation furnace according to claim 7, characterized in that, A gasket (7) is provided between two adjacent heat insulation boards (6).

10. The vertical high-temperature oxidation furnace according to claim 7, characterized in that, The heat insulation board (6) has multiple second through holes (61) on its outer side, and the second through holes (61) are used to allow the heat insulation board (6) to be installed through.

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