Silicon carbide epitaxial furnace wafer tray
By designing a silicon carbide wafer tray and utilizing concentric annular protrusion support points and a spiral flow channel structure, the problems of impurity release and deformation of the wafer tray at high temperatures were solved, achieving stable wafer support and airflow uniformity, and improving the uniformity of the epitaxial layer and device performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU RONGFANG SEMICONDUCTOR TECHNOLOGY CO LTD
- Filing Date
- 2025-05-21
- Publication Date
- 2026-04-17
AI Technical Summary
The wafer trays in existing silicon carbide epitaxial furnaces are prone to releasing impurities at high temperatures. The high coefficient of thermal expansion causes the trays to deform, affecting wafer flatness and uneven airflow distribution, resulting in uneven epitaxial layer thickness and doping concentration, which affects device performance.
The wafer tray, made of silicon carbide, features concentric ring-shaped raised support points for point contact support, a central through-hole to form a vertical gas flow channel, spiral guide grooves at the edges to guide gas flow, and a bottom reinforcing rib structure to disperse thermal stress and improve tray rigidity and temperature field uniformity.
Maintaining wafer stability at high temperatures, preventing slippage, improving airflow and temperature field uniformity, reducing thermal stress accumulation, and enhancing epitaxial layer uniformity and device performance.
Smart Images
Figure CN224133249U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor manufacturing equipment technology, and specifically discloses a silicon carbide epitaxial furnace wafer tray. Background Technology
[0002] Silicon carbide (SiC), with its superior properties such as high critical breakdown field strength, high saturated electron drift velocity, and high thermal conductivity, plays an important role in next-generation high-efficiency, high-voltage power electronic devices. It is a key third-generation semiconductor material for both military and civilian applications. In the SiC semiconductor industry chain, SiC epitaxial wafers are the basic material used to manufacture power devices, grown from SiC wafers as substrates. Currently, SiC epitaxial wafers are typically prepared using vapor phase epitaxy (VPE). In VPE, reactant gases are transported to the wafer surface, where a reaction occurs under specific temperature conditions to form the desired epitaxial layer. The uniformity of the epitaxial layer is a crucial quality criterion. To obtain epitaxial wafers with high uniformity, controlling the uniformity of the flow field and temperature field of the reactant gases on the wafer surface is a critical step.
[0003] Silicon carbide epitaxial furnaces grow epitaxial layers at high temperatures (typically above 1500℃), placing extremely high demands on the high-temperature resistance, thermal stability, and chemical stability of the wafer trays. In existing technologies, wafer trays are mostly made of graphite; however, graphite easily releases impurities at high temperatures, contaminating the wafer, and its high coefficient of thermal expansion can easily cause tray deformation, affecting wafer flatness. Furthermore, traditional tray structures are simple in design, resulting in unstable wafer fixation and uneven airflow distribution, leading to uneven epitaxial layer thickness and doping concentration, thus affecting device performance. Utility Model Content
[0004] This invention proposes a silicon carbide epitaxial furnace wafer tray. The concentric ring-shaped raised support points reduce the contact area, thereby reducing the accumulation of thermal stress and preventing wafer slippage. Through holes form vertical gas flow channels, promoting the uniform diffusion of reactive gases to the wafer surface. Spiral guide grooves at the edges guide the gas to flow along the spiral path, improving the temperature field uniformity between the wafer edge and the center region.
[0005] This utility model is implemented as follows: a silicon carbide epitaxial furnace wafer tray, comprising:
[0006] The substrate is made of silicon carbide.
[0007] A wafer fixing structure includes at least two concentric rings of raised support points disposed on the surface of a substrate;
[0008] The airflow channel includes multiple through holes in the central region of the substrate and spiral guide grooves located at the edge of the substrate;
[0009] The deformation-resistant structure includes reinforcing ribs fixedly connected to the bottom of the base, wherein the thickness of the reinforcing ribs is 1 / 3 to 1 / 2 of the thickness of the base.
[0010] The mounting interface includes multiple locating pin holes distributed along the edge of the base.
[0011] As a preferred wafer tray for a silicon carbide epitaxial furnace according to this utility model, the height of the raised support point is 0.5-1.5mm, and the top is spherical or flat, for contact with the wafer forming point.
[0012] As a preferred wafer tray for a silicon carbide epitaxial furnace according to this utility model, the diameter of the through hole is 2-5mm, and the depth of the spiral guide groove is 1-3mm and the width is 3-6mm.
[0013] As a preferred embodiment of the silicon carbide epitaxial furnace wafer tray of this utility model, the number of the concentric ring-arranged protruding support points is 12-36 per ring, and the distance between adjacent support points is 8-15mm.
[0014] As a preferred embodiment of the silicon carbide epitaxial furnace wafer tray of this utility model, the through holes are distributed in a regular hexagonal pattern in the central region of the substrate, and the number of through holes is 20-50.
[0015] As a preferred embodiment of the silicon carbide epitaxial furnace wafer tray of this utility model, the reinforcing ribs are a cross structure of radial and circular structures.
[0016] As a preferred wafer tray for a silicon carbide epitaxial furnace according to this utility model, the substrate has a diameter of 200-450mm and a thickness of 10-20mm.
[0017] The beneficial effects of this utility model are:
[0018] The substrate of this invention is made of silicon carbide, which utilizes its high thermal conductivity and low coefficient of thermal expansion to maintain structural stability at high temperatures and reduce wafer displacement caused by thermal expansion.
[0019] The concentric ring-shaped raised support points support the wafer by point contacting the spherical or planar surface, reducing the contact area and avoiding large-area contact between the wafer and the tray surface, thereby reducing the accumulation of thermal stress and preventing wafer slippage.
[0020] The through-holes in the central region form a vertical gas flow channel, which promotes the uniform diffusion of the reactant gas to the wafer surface. The spiral guide grooves at the edge guide the gas to flow along the spiral path, prolonging the gas residence time and forming turbulence, thus improving the temperature field uniformity between the wafer edge and the central region.
[0021] The bottom reinforcing ribs adopt a radial and circular intersecting structure, which disperses the concentrated areas of thermal stress, suppresses the warping deformation of the substrate at high temperatures, and improves the overall rigidity of the pallet. Attached Figure Description
[0022] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.
[0023] Figure 1 This is a top view of the overall structure of this utility model;
[0024] Figure 2 This is a bottom view of the overall structure of this utility model.
[0025] The markings in the diagram are: 1. Base; 2. Raised support point; 3. Through hole; 4. Reinforcing rib; 5. Spiral guide groove; 6. Positioning pin hole. Detailed Implementation
[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding its content. Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.
[0027] Please see Figure 1-2 A silicon carbide epitaxial furnace wafer tray, comprising:
[0028] Substrate 1, Substrate 1 is made of silicon carbide;
[0029] The wafer fixing structure includes at least two concentric rings of raised support points 2 disposed on the surface of the substrate 1;
[0030] The airflow channel includes multiple through holes 3 opened in the central region of the substrate 1, and a spiral guide groove 5 located in the edge region of the substrate 1;
[0031] The deformation-resistant structure includes a reinforcing rib 4 fixedly connected to the bottom of the base 1, the thickness of which is 1 / 3 to 1 / 2 of the thickness of the base 1;
[0032] The mounting interface includes multiple positioning pin holes 6 distributed along the edge of the base 1.
[0033] In this embodiment: the substrate 1 is made of silicon carbide, which utilizes its high thermal conductivity and low coefficient of thermal expansion to maintain structural stability at high temperatures and reduce wafer displacement caused by thermal expansion;
[0034] The concentric ring-shaped raised support points 2 support the wafer by point contacting the spherical or planar surface, reducing the contact area and avoiding large-area contact between the wafer and the tray surface, thereby reducing the accumulation of thermal stress and preventing the wafer from sliding.
[0035] The through-hole 3 in the central region forms a vertical gas flow channel, which promotes the uniform diffusion of the reaction gas to the wafer surface. The spiral guide groove 5 at the edge guides the gas to flow along the spiral path, prolongs the gas residence time and forms turbulence, improving the temperature field uniformity between the wafer edge and the central region.
[0036] The bottom reinforcing rib 4 adopts a radial and circular intersecting structure, which disperses the concentrated area of thermal stress, suppresses the warping deformation of the base 1 at high temperature, and improves the overall rigidity of the pallet;
[0037] The positioning pin hole 6 cooperates with the furnace body clamp to achieve quick alignment and installation of the tray, avoiding displacement caused by thermal expansion differences at high temperatures.
[0038] As a technical optimization of this utility model, the height of the protruding support point 2 is 0.5-1.5mm, and the top is a spherical or flat surface, used to form a point contact with the wafer.
[0039] In this embodiment: the height of the raised support point 2 is 0.5-1.5mm, and the top is spherical or flat, which is used to form point contact with the wafer, reduce the contact area, avoid the wafer from being in contact with the tray surface over a large area, thereby reducing the accumulation of thermal stress and preventing the wafer from sliding.
[0040] As a technical optimization of this utility model, the diameter of the through hole 3 is 2-5mm, and the depth of the spiral guide groove 5 is 1-3mm and the width is 3-6mm.
[0041] In this embodiment: the diameter of the through hole 3 is 2-5mm, the depth of the spiral guide groove 5 is 1-3mm and the width is 3-6mm. The through hole 3 forms a vertical gas flow channel, which promotes the uniform diffusion of the reaction gas to the wafer surface. The edge spiral guide groove 5 guides the gas to flow along the spiral path, prolongs the gas residence time and forms turbulence.
[0042] As a technical optimization of this utility model, the number of concentric ring-arranged protruding support points 2 is 12-36 per ring, and the distance between adjacent support points is 8-15mm.
[0043] In this embodiment, the number of concentric ring-shaped protrusions 2 is 12-36 per ring, which reduces the contact area, avoids large-area contact between the wafer and the tray surface, thereby reducing thermal stress accumulation and preventing wafer slippage.
[0044] As a technical optimization of this utility model, the through holes 3 are distributed in a regular hexagonal shape in the central region of the substrate 1, and the number of through holes 3 is 20-50.
[0045] In this embodiment: the vias 3 are distributed in a regular hexagonal pattern in the central region of the substrate 1. The vias 3 in the central region form a vertical gas flow channel, which promotes the uniform diffusion of the reaction gas to the wafer surface.
[0046] As a technical optimization of this utility model, the reinforcing rib 4 is a cross structure of radial and circular structures.
[0047] In this embodiment, the reinforcing rib 4 is a cross structure of radial and circular structures, which disperses the concentrated area of thermal stress, suppresses the warping deformation of the substrate 1 at high temperature, and improves the overall rigidity of the tray.
[0048] As a technical optimization of this utility model, the diameter of the substrate 1 is 200-450mm and the thickness is 10-20mm.
[0049] In this embodiment: the diameter of the base 1 is 200-450mm and the thickness is 10-20mm to ensure the strength and rigidity of the base.
[0050] The working principle and usage process of this utility model are as follows: The substrate 1 is made of silicon carbide, which utilizes its high thermal conductivity and low coefficient of thermal expansion to maintain structural stability at high temperatures and reduce wafer displacement caused by thermal expansion. The concentric ring-shaped raised support points 2 support the wafer by point contact with the spherical or planar surfaces, reducing the contact area and avoiding large-area contact between the wafer and the tray surface, thereby reducing thermal stress accumulation and preventing wafer slippage. The through holes 3 in the central area form a vertical gas flow channel, promoting the uniform diffusion of reactive gases to the wafer surface. The spiral guide grooves 5 at the edge guide the gas to flow along the spiral path, prolonging the gas residence time and forming turbulence, improving the temperature field uniformity between the wafer edge and the central area. The bottom reinforcing ribs 4 adopt a radial and circular intersecting structure, which disperses the concentrated area of thermal stress, suppresses the warping deformation of the substrate 1 at high temperatures, and improves the overall rigidity of the tray. The positioning pin holes 6 cooperate with the furnace body clamps to achieve rapid alignment and installation of the tray, avoiding displacement caused by thermal expansion differences at high temperatures.
[0051] In the description of this utility model, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inner", "outer", "back", "middle", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this utility model.
[0052] However, the above description is only a specific embodiment of this utility model and should not be construed as limiting the scope of implementation of this utility model. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of this utility model should still fall within the scope of the claims of this utility model.
Claims
1. A silicon carbide epitaxial furnace wafer tray, characterized by: include: The substrate (1) is made of silicon carbide. The wafer fixing structure includes at least two concentric rings of raised support points (2) disposed on the surface of the substrate (1); The airflow channel includes multiple through holes (3) opened in the central region of the substrate (1) and spiral guide grooves (5) located in the edge region of the substrate (1); The anti-deformation structure includes a reinforcing rib (4) fixedly connected to the bottom of the base (1), wherein the thickness of the reinforcing rib is 1 / 3 to 1 / 2 of the thickness of the base (1); The mounting interface includes multiple positioning pin holes (6) distributed on the edge of the base (1).
2. A silicon carbide epitaxial furnace wafer tray as defined in claim 1, wherein: The raised support point (2) has a height of 0.5-1.5 mm and a spherical or flat top for making point contact with the wafer.
3. A silicon carbide epitaxial furnace wafer tray as defined in claim 1, wherein: The diameter of the through hole (3) is 2-5 mm, and the depth of the spiral guide groove (5) is 1-3 mm and the width is 3-6 mm.
4. A silicon carbide epitaxial growth wafer tray as defined in claim 1, wherein: The number of the concentric ring-shaped protruding support points (2) is 12-36 per ring, and the distance between adjacent support points is 8-15mm.
5. A silicon carbide epitaxial growth wafer tray as defined in claim 1, wherein: The through holes (3) are distributed in a regular hexagonal pattern in the central region of the substrate (1), and the number of through holes (3) is 20-50.
6. A silicon carbide epitaxial growth wafer tray as defined in claim 1, wherein: The reinforcing rib (4) is a cross structure of radial and circular structures.
7. A silicon carbide epitaxial growth wafer tray as defined in claim 1, wherein: The substrate (1) has a diameter of 200-450 mm and a thickness of 10-20 mm.