Horizontal epitaxial furnace
By introducing filtration and speed equalization components into the gas delivery unit of the horizontal epitaxial furnace, the problems of dust accumulation in the cross section and unstable gas flow rate were solved, thereby improving the quality and uniformity of the epitaxial wafers.
Patent Information
- Application Number
- CN202520037135.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2035-01-07
AI Technical Summary
In horizontal epitaxial furnaces, dust and particulate matter tend to accumulate in the cross-shaped structure, causing gas to carry contaminants into the cavity, affecting the quality of the epitaxial wafer. Furthermore, the unstable radial flow rate of the gas leads to abnormal film thickness and doping uniformity.
A gas treatment unit is introduced into the gas delivery unit, including a filter assembly and a velocity equalization assembly. The filter assembly is used to remove particulate contaminants, and the velocity equalization assembly is used to uniformly distribute the airflow. The gas treatment unit is located on the side close to the epitaxial growth unit and uses a honeycomb panel and activated carbon filter assembly to ensure gas cleanliness and stable flow rate.
It effectively removes particulate matter from the gas, ensures uniform gas distribution, improves the production quality and doping uniformity of epitaxial wafers, and reduces film thickness inhomogeneity.
Smart Images
Figure CN223793273U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor equipment technology, and in particular to a horizontal epitaxial furnace. Background Technology
[0002] Currently, chemical vapor deposition (CVD) epitaxial systems have become the main method for preparing silicon carbide (SiC) epitaxial films due to their low temperature, ease of control, and good film uniformity. Silicon carbide epitaxial furnaces are mainly classified into horizontal, vertical, and planetary types. For horizontal silicon carbide epitaxial furnaces, the gas inlet is horizontal. The gas enters the quartz square tube through a cross-shaped pipe, and then splits into three gas paths (central and side) to enter the chamber for reaction.
[0003] However, the cross-shaped structure in horizontal epitaxial furnaces easily accumulates dust and particulate matter. If the cross-shaped structure becomes contaminated, the gas entering the furnace cavity can easily carry contaminants, resulting in abnormal epitaxial wafer quality. Furthermore, the gas exiting the cross-shaped structure travels a considerable distance from the furnace cavity, during which it is easily disturbed, causing instability in its radial flow velocity and ultimately leading to abnormal film thickness and doping uniformity in the epitaxial wafers. Therefore, it is necessary to modify existing horizontal epitaxial furnaces. Summary of the Invention
[0004] One objective of this application is to provide a horizontal epitaxial furnace that can improve the quality of epitaxial wafer production.
[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: a horizontal epitaxial furnace, including a gas conveying unit and an epitaxial growth unit, and further including at least one gas processing unit disposed within the gas conveying unit. The gas processing unit includes at least one filter component and at least one constant velocity component. The filter component is used to remove particulate contaminants carried in the conveying gas. The constant velocity component has a plurality of gas holes evenly distributed on it to make the gas flow uniformly distributed. The constant velocity component is disposed on the side of the gas processing unit close to the epitaxial growth unit.
[0006] As a preferred embodiment, the pore density on the uniform velocity component is 9 to 100 pores per square centimeter.
[0007] As a preferred embodiment, all the pores on the uniform speed component have the same diameter.
[0008] As a preferred embodiment, the constant speed component is a honeycomb panel.
[0009] As a preferred option, the honeycomb panel is made of quartz material.
[0010] As a preferred embodiment, the gas processing unit includes at least two of the honeycomb panels, and at least one of the honeycomb panels is respectively disposed at the air inlet end and the air outlet end of the filter assembly.
[0011] As a preferred embodiment, the filter assembly is an activated carbon filter assembly.
[0012] As a preferred embodiment, in any of the horizontal epitaxial furnaces described above, a transition piece is further provided between the gas conveying unit and the epitaxial growth unit. The transition piece is used to reduce the influence of high temperature on the epitaxial growth unit and the gas conveying unit. The total length of the gas conveying unit is L, and the distance between the gas processing unit and the transition piece is L1, where 1 / 3L≤L1≤2 / 3L.
[0013] As a preferred embodiment, the gas processing unit is located in the central region of the gas delivery unit, where L1 = 1 / 2L.
[0014] As a preferred embodiment, the gas delivery unit includes at least two gas delivery pipes, each of which is provided with a gas processing unit, and each gas processing unit is equidistant from the epitaxial growth unit.
[0015] Compared with the prior art, the beneficial effects of this application are as follows:
[0016] This application proposes to add a gas processing unit to the gas delivery unit of a horizontal epitaxial furnace. This gas processing unit can not only remove impurities such as particulate matter from the gas to avoid the possible impact of particulate matter on the quality of the epitaxial surface, but also make the radial flow velocity of the gas more uniform, reducing the problems of poor epitaxial film thickness and doping uniformity caused by unstable radial flow velocity of the gas. Attached Figure Description
[0017] Figure 1 This is a top view of a horizontal epitaxial furnace in the prior art;
[0018] Figure 2 This is a top view of the horizontal epitaxial furnace in an embodiment of this application;
[0019] Figure 3 This is a right-side view of the horizontal epitaxial furnace gas processing unit in an embodiment of this application;
[0020] Figure 4 This is a top view of a horizontal epitaxial furnace according to another embodiment of this application;
[0021] Figure 5 This is a top view of the horizontal epitaxial furnace gas processing unit in an embodiment of this application;
[0022] Figure 6 This is a top view of a horizontal epitaxial furnace in another embodiment of this application.
[0023] In the figure: 1. Gas delivery unit; 10. Gas delivery end; 11. First pipeline; 12. Second pipeline; 13. Third pipeline; 2. Gas processing unit; 21. Filter assembly; 210. Inlet end; 211. Outlet end; 22. Uniform speed assembly; 220. Air hole; 3. Transition component; 4. Epitaxial growth unit. Detailed Implementation
[0024] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.
[0025] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application 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. They should not be construed as limiting the specific protection scope of this application.
[0026] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.
[0027] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.
[0028] like Figure 1As shown, the existing horizontal epitaxial furnace includes a gas delivery unit 1, a transition piece 3, and an epitaxial growth unit 4. The gas delivery unit 1 includes a first pipe 11, a second pipe 12, and a third pipe 13. The second pipe 12 is wider than the first pipe 11 and the third pipe 13 to ensure that the gas can uniformly cover the substrate surface. The first pipe 11 and the third pipe 13 are symmetrically arranged and have equal widths to control the gas flow rate, ensuring uniform gas distribution and thorough mixing. Because the temperature inside the gas chamber of the epitaxial growth unit 4 is very high during epitaxial wafer production, a transition piece 3 is usually added between the gas delivery unit 1 and the epitaxial growth unit 4 to block the high temperature and prevent damage to the quartz square tube used for gas intake. The reaction gas required for epitaxial wafer growth is delivered through the gas delivery end 10 of the gas delivery unit 1 to the first pipe 11, the second pipe 12, and the third pipe 13, and then delivered from the transition piece 3 to the epitaxial growth unit 4 to participate in the growth of the epitaxial wafer. Furthermore, existing horizontal epitaxial furnaces are equipped with crossbars for distributing and changing the direction of gas flow. Gas typically passes through the crossbars before being delivered to gas delivery unit 1. However, during operation, the crossbars in the epitaxial furnace are prone to dust accumulation. When the incoming reactive gas passes through the crossbars, contaminants on the crossbars are easily carried into the epitaxial growth unit 4, thus affecting the production quality of the epitaxial wafers. Moreover, to avoid excessively high or low gas concentrations in localized areas that could affect the uniformity of the epitaxial layer, existing horizontal epitaxial furnaces typically have a considerable distance between the gas exiting the crossbars and the cavity. This excessive distance can easily cause uneven radial flow velocity of the gas, leading to abnormal film thickness and doping uniformity in the epitaxial wafers.
[0029] To address the problems existing in current horizontal epitaxial furnaces, this application provides a novel horizontal epitaxial furnace capable of improving the quality and doping uniformity of silicon carbide epitaxial wafers. For example... Figure 2 As shown, the horizontal epitaxial furnace in this application includes a gas delivery unit 1, a gas processing unit 2, a transition piece 3, and an epitaxial growth unit 4. The gas processing unit 2 is respectively disposed in the first pipe 11, the second pipe 12, and the third pipe 13 of the gas delivery unit 1. Further, the gas processing unit 2 includes a filter assembly 21 and a constant speed assembly 22. The filter assembly 21 is disposed on one side near the gas delivery end 10 of the gas delivery unit 1 and is used to remove impurities such as particulate matter carried in the delivery gas, which can objectively increase the service life of the gas pipeline and increase the tolerance of the gas pipeline cleanliness. The constant speed assembly 22 has a plurality of gas holes 220 evenly distributed on one side near the epitaxial growth unit 4 and is disposed on one side to ensure that the gas is delivered to the epitaxial growth unit 4 evenly and stably.
[0030] In some embodiments, the gas delivery unit 1 includes at least two gas delivery pipes, each of which is provided with a gas processing unit 2. Each gas processing unit 2 is equidistant from the epitaxial growth unit 4. Figure 2 As shown, each gas processing unit 2 is located at the same position. Since the path length of the gas through the gas processing unit 2 is consistent, the speed at which the gas reaches the epitaxial growth unit 4 can also be consistent, thereby ensuring that the gas entering the epitaxial growth unit 4 can be mixed uniformly.
[0031] In some embodiments, the pore density on the uniform velocity assembly 22 is 9 to 100 pores per square centimeter. The higher the pore density on the uniform velocity assembly 22, the more radial splitting of the gas occurs, which is more conducive to achieving uniform gas distribution in the radial direction. In addition, the higher the pore density, the greater the reduction effect on the lateral gas flow velocity, and the more stable the lateral gas flow velocity. This allows the gas in each gas delivery pipe to be more thoroughly and uniformly mixed when entering the epitaxial growth unit 4, thereby improving the production quality of the epitaxial wafer.
[0032] In some embodiments, the apertures of each pore on the uniform speed component 22 are the same, and the gas is more evenly distributed radially when it enters the uniform speed component 22, so that the gas delivered to the epitaxial growth unit 4 is mixed more evenly, thereby ensuring that the growth conditions of the entire epitaxial wafer surface are consistent and improving the uniformity of the epitaxial wafer growth rate and thickness.
[0033] In some embodiments, such as Figure 3 As shown, the uniform velocity component 22 employs a honeycomb panel with multiple equilateral hexagonal pores 220. This effectively disperses the airflow in the gas delivery unit 1, dividing the gas into multiple fine, uniform streams as it passes through the honeycomb panel. This ensures a stable and uniform radial flow velocity of the gas before entering the epitaxial growth unit 4, reducing problems such as poor epitaxial film thickness and doping uniformity caused by unstable radial flow velocity. Furthermore, the honeycomb panel has higher porosity and lower mass density than other matrix materials, effectively reducing airflow turbulence, particularly lateral turbulence. This allows the gas to diffuse radially, improving the stability and uniformity of radial gas flow and preventing localized blockage. In some embodiments, the pores on the honeycomb panel can also be circular, square, or other shapes.
[0034] In some embodiments, the honeycomb panel is made of quartz material. Quartz has high temperature resistance and corrosion resistance. Therefore, even if the honeycomb panel made of quartz is placed close to the epitaxial growth unit 4 with extremely high internal reaction temperature, its function and service life will not be greatly affected.
[0035] In some embodiments, the filter component 21 and the constant velocity component 22 in the gas processing unit 2 are combined into one unit, which can both perform gas impurity filtration and maintain a uniform and stable gas flow rate. In other embodiments, the filter component 21 and the constant velocity component 22 may also be provided separately.
[0036] In some embodiments, such as Figure 4 As shown, the constant velocity component 22 in the gas processing unit 2 consists of two honeycomb panels, respectively disposed on both sides of the inlet end 210 and the outlet end 211 of the filter component 21. The gas is transported to the first pipe 11, the second pipe 12, and the third pipe 13 through the gas delivery end 10 of the gas delivery unit 1. Then, it first passes through the honeycomb panel on the side of the inlet end 210 for radial flow uniformity. After the filter component 21 filters out particulate impurities in the gas, it passes through the honeycomb panel on the side of the outlet end 211 again for radial flow uniformity, so that the gas always maintains a stable and uniform flow state in the delivery pipe.
[0037] In some embodiments, the filter component 21 in the gas treatment unit 2 is an activated carbon filter component 21. Activated carbon is low in cost and has a very strong adsorption capacity, which can effectively remove impurities from the gas and improve the efficiency of gas impurity treatment. Figure 5 As shown, the uniform velocity component 22 has multiple uniformly distributed pores 220 of a certain length inside. Activated carbon is directly filled into these pores 220 of the uniform velocity component 22 to form a filter component 21, which filters particulate matter and other impurities in the gas. This gas treatment unit 2 can simultaneously remove particulate matter and other impurities from the gas and stabilize the gas flow rate. Moreover, since the filter component 21 and the uniform velocity component 22 are integrated, it saves space in the gas treatment unit 2, simplifies the manufacturing process of the gas treatment unit 2, and reduces equipment production costs.
[0038] In some embodiments, the gas processing unit 2 includes at least one filter component 21 and a constant velocity component 22, which can simultaneously remove gas impurities and maintain a uniform and stable radial flow rate of the gas.
[0039] In some embodiments, the gas processing unit 2 is provided with a filter component 21 and a constant speed component 22 separately. The filter component 21 can be provided first and then the constant speed component 22 can be provided; or the constant speed component 22 can be provided at both ends and the filter component 21 can be provided in the middle. When the filter component 21 or the constant speed component 22 needs to be replaced or maintained, it is not necessary to disassemble the entire gas processing unit 2. Only the component that needs to be maintained needs to be replaced, which can reduce maintenance time and cost.
[0040] In some embodiments, a filter assembly 21 is preferably provided near the gas delivery end 10 in the gas delivery unit 1, followed by a constant velocity assembly 22. Thus, the gas entering the gas delivery unit 1 first passes through the filter assembly 21 to remove particulate matter and other impurities from the gas after passing through the cross section, minimizing the risk of epitaxial wafer quality degradation and abnormalities caused by particulate matter and other impurities, and increasing pipeline lifespan. Subsequently, the gas enters the constant velocity assembly 22, effectively controlling the gas flow rate to be stable and uniform before reaching the epitaxial growth unit 4, reducing problems such as poor epitaxial wafer thickness and doping uniformity caused by unstable radial gas flow rate.
[0041] Since the temperature required inside the epitaxial growth unit 4 is extremely high during epitaxial growth, if the gas processing unit 2 is close to the transition piece 3, it may be affected by the high temperature inside the epitaxial growth unit 4, resulting in deformation or damage. Therefore, in order to improve the service life of the gas processing unit 2, the gas processing unit 2 needs to be set in a suitable position.
[0042] In some embodiments, such as Figure 6 As shown, the total length of the gas delivery unit 1 is L, and the distance between the gas processing unit 2 and the transition piece 3 is L1. 1 / 3L≤L1≤2 / 3L. The gas processing unit 2, which is set within this distance range, is not easily affected by the high temperature when the epitaxial growth unit 4 grows the epitaxial wafer. This avoids the aging and deterioration of the components in the gas processing unit 2 caused by long-term high-temperature operation, and improves the reliability and service life of the components in the gas processing unit 2.
[0043] Further optimization, such as Figure 6 As shown, the gas processing unit 2 is located in the middle region of the gas delivery unit 1, with L1 = 1 / 2L. This avoids the gas processing unit 2 from being affected by the high temperature inside the epitaxial growth unit 4, and further improves the service life of the gas processing unit 2.
[0044] In some embodiments, the filter assembly 21 may be a filter screen, a reaction filter, etc.
[0045] In some embodiments, the filter component 21 can also be replaced by some impurity adsorption materials, such as activated carbon, ultracarbon materials, filter cotton, silica gel, etc.
[0046] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.
Claims
1. A horizontal epitaxial furnace comprising a gas delivery unit and an epitaxial growth unit, characterized by, The gas delivery unit further comprises at least one gas treatment unit arranged in the gas delivery unit, the gas treatment unit comprising at least one filter assembly and at least one uniformity assembly, the filter assembly being used to remove particulate contaminants carried in the delivery gas, and the uniformity assembly having a plurality of gas holes uniformly distributed thereon and used to uniformly distribute the gas flow, the uniformity assembly being arranged close to one side of the epitaxial growth unit.
2. A horizontal epitaxial furnace as claimed in claim 1, wherein The density of the gas holes on the uniformity assembly is 9-100 gas holes per square centimeter.
3. A horizontal epitaxial furnace as claimed in claim 2, wherein The diameters of the gas holes on the uniformity assembly are the same.
4. A horizontal epitaxial furnace as claimed in claim 1, wherein The uniformity assembly is a honeycomb plate.
5. A horizontal epitaxial furnace as claimed in claim 4, wherein The honeycomb plate is made of quartz.
6. A horizontal epitaxial furnace as claimed in claim 4, wherein The gas treatment unit comprises at least two honeycomb plates, and at least one honeycomb plate is arranged at the gas inlet end and the gas outlet end of the filter assembly.
7. A horizontal epitaxial furnace as claimed in claim 1, wherein The filter assembly is an activated carbon filter assembly.
8. A horizontal epitaxial furnace as claimed in any one of claims 1 to 7, wherein The gas delivery unit and the epitaxial growth unit further comprise a transition piece arranged therebetween, the transition piece being used to reduce the influence of high temperature on the epitaxial growth unit and the gas delivery unit, the total length of the gas delivery unit being L, the distance between the gas treatment unit and the transition piece being L1, and 1 / 3L≤L1≤2 / 3L.
9. A horizontal epitaxial furnace as claimed in claim 8, wherein The gas treatment unit is arranged in the middle region of the gas delivery unit, and L1=1 / 2L.
10. A horizontal epitaxial furnace as claimed in any one of claims 1 to 7, wherein The gas delivery unit comprises at least two gas delivery pipes, and each gas delivery pipe comprises one gas treatment unit, and the distances between the gas treatment units and the epitaxial growth unit are the same.