A tray structure for silicon carbide epitaxial equipment

Abstract

The utility model relates to the technical field of semiconductor manufacturing equipment, specifically disclose a tray structure for silicon carbide epitaxial equipment, including tray base, the concentric circle arrangement of multiple wafer bearing positions is provided with in the upper end surface of circular tray base, each wafer bearing position is the recessed structure of ladder, including embedding setting bottom support ring in the upper end of circular tray base, the inclined transition surface is connected with the upper surface of tray base the outer edge of bottom support ring's upper end surface, through recessed bearing position structure of ladder, the risk of wafer thermal deformation breakage is reduced significantly, radial flow guide groove optimizes reaction gas radial distribution uniformity, and the composite structure of graphite matrix and silicon carbide coating and the processing of round corner edge are matched, effectively improve the anti -peeling ability of coating and equipment service life under high temperature working condition, finally realize the synchronous improvement of epitaxial layer thickness consistency and production yield.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing equipment technology, and specifically discloses a tray structure for silicon carbide epitaxial equipment. Background Technology

[0002] Silicon carbide epitaxial growth equipment is a key component in the manufacture of high-performance semiconductor chips. Its core component, the wafer tray, is used to support the wafer and perform chemical vapor deposition at high temperatures. Current mainstream wafer trays employ a graphite substrate with a protective coating, utilizing a special surface structure to optimize wafer heating uniformity and gas flow. The structural rationality of these trays directly affects the quality stability and production efficiency of the epitaxial layer.

[0003] However, existing pallet designs still have significant limitations:

[0004] Poor thermal deformation compatibility; at high temperatures, the wafer and the tray expand to different degrees due to material differences, and the wafer edge is easily squeezed and damaged.

[0005] Traditional uniformly distributed channels have difficulty balancing airflow between the center and the edge regions, resulting in uneven epitaxial growth thickness.

[0006] The coating on the sharp edges of the tray is prone to peeling off during long-term high-temperature use, which not only contaminates the reaction environment but also accelerates the damage to the substrate. Utility Model Content

[0007] This invention proposes a tray structure for silicon carbide epitaxial equipment. The stepped recessed bearing structure significantly reduces the risk of wafer thermal deformation and breakage. The radial guide grooves optimize the radial distribution uniformity of the reactive gas. Combined with the composite structure of graphite substrate and silicon carbide coating and the rounded edge treatment, it effectively improves the coating's anti-peeling ability and the equipment's service life under high-temperature conditions.

[0008] This utility model is implemented as follows: a tray structure for silicon carbide epitaxial equipment, comprising:

[0009] The tray base has multiple wafer carrier positions arranged in concentric circles on its upper surface;

[0010] Each of the wafer carrier sites is a stepped recessed structure, including:

[0011] A bottom support ring is embedded in the upper part of the circular tray base;

[0012] An inclined transition surface connects the outer edge of the upper end face of the bottom support ring to the upper surface of the tray base.

[0013] As a preferred embodiment of the tray structure for silicon carbide epitaxial equipment according to this utility model, the inclined angle of the inclined transition surface is 15°-45°, and the surface is polished.

[0014] As a preferred embodiment of the tray structure for silicon carbide epitaxial equipment according to this utility model, the upper surface of the tray base is provided with guide grooves radially distributed around the center of the tray base. Multiple guide grooves are staggered with multiple wafer carrier positions. The depth of the guide grooves is 1-3mm and the width is 2-5mm.

[0015] As a preferred embodiment of the tray structure for silicon carbide epitaxial equipment according to this utility model, the tray substrate is made of high-purity graphite material and the surface is covered with a silicon carbide coating with a coating thickness of 50-200μm.

[0016] As a preferred embodiment of the tray structure for silicon carbide epitaxial equipment of this utility model, a countersunk hole is provided at the center of the lower end face of the tray base, and a threaded ceramic sleeve is fixedly connected to the inner side of the countersunk hole.

[0017] As a preferred embodiment of the tray structure for silicon carbide epitaxial equipment according to this utility model, the inner edge of the bottom support ring is provided with a rounded corner structure with a rounded corner radius R≥0.5mm.

[0018] The beneficial effects of this utility model are:

[0019] This invention significantly reduces the risk of wafer thermal deformation and breakage through a stepped recessed bearing structure, optimizes the radial distribution uniformity of reactive gases through radial guide grooves, and effectively improves the coating's anti-peeling ability and equipment lifespan under high-temperature conditions by combining a composite structure of graphite substrate and silicon carbide coating with rounded edge treatment. Ultimately, it achieves simultaneous improvement in epitaxial layer thickness consistency and production yield. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a top view of the overall structure of this utility model;

[0022] Figure 2 This is a cross-sectional view of the wafer carrier site of this utility model;

[0023] Figure 3 This is a magnified three-dimensional structural diagram of the wafer carrier site of this utility model;

[0024] Figure 4 This is a bottom view of the overall structure of this utility model.

[0025] The markings in the diagram are: 1. Tray base; 2. Wafer carrier; 3. Bottom support ring; 4. Inclined transition surface; 5. Guide groove; 6. Countersunk hole; 7. Threaded ceramic sleeve. 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 1-4 A tray structure for a silicon carbide epitaxial device, comprising:

[0028] The upper surface of the circular tray base 1 is provided with multiple wafer carrier positions 2 arranged in concentric circles;

[0029] Each wafer carrier site 2 has a stepped recessed structure, including:

[0030] A bottom support ring 3 is embedded in the upper end of the circular tray base 1;

[0031] Inclined transition surface 4 connects the outer edge of the upper end face of the bottom support ring 3 with the upper surface of the tray base 1.

[0032] In this embodiment: the surface of the tray base 1 is provided with concentrically arranged wafer support positions 2, each support position adopts a stepped recessed structure, the bottom support ring 3 is embedded in the upper end of the tray base 1 to provide narrow ring support, the wafer only contacts the 0.8mm wide ring surface of the bottom support ring 3, which significantly reduces thermal stress; the inclined transition surface 4 connects the outer edge of the bottom support ring 3 and the upper surface of the tray base 1 at a 30° angle, the polished inclined surface guides the reactive gas to diffuse towards the center of the wafer, improving epitaxial uniformity, the surface of the tray base 1 is provided with radial guide grooves 5, which force the airflow to flow directionally from the center to the edge, eliminating the concentration difference between the center and the edge; the tray base 1 is made of graphite substrate covered with an 80μm silicon carbide coating, combined with the rounded corners on the inner side of the bottom support ring 3, to prevent coating peeling and contamination; the bottom countersunk hole 6 fixes the threaded ceramic sleeve 7, and the rotating shaft is connected by ceramic bolts to realize the smooth rotation of the tray.

[0033] As a technical optimization of this utility model, the inclined angle of the inclined transition surface 4 is 15°-45°, and the surface is polished.

[0034] In this embodiment, the 15°-45° tilt angle of the inclined transition surface 4, combined with the polished surface, reduces airflow resistance and forms a laminar gas film, thereby reducing growth defects caused by turbulence at the wafer edge.

[0035] As a technical optimization of this utility model, the upper surface of the tray base 1 is provided with guide grooves 5 radially distributed with the center of the tray base 1 as the center. Multiple guide grooves 5 are staggered with multiple wafer carrier positions 2. The depth of the guide grooves 5 is 1-3mm and the width is 2-5mm.

[0036] In this embodiment, the radial guide channels 5 and the wafer support sites 2 are staggered, breaking the symmetrical flow field of the traditional uniformly distributed channels, so that the gas is pressurized along the radial gradient, thus solving the problem of lagging edge growth rate.

[0037] As a technical optimization of this utility model, the tray substrate 1 is made of high-purity graphite material and covered with a silicon carbide coating with a coating thickness of 50-200μm.

[0038] In this embodiment, the graphite substrate and silicon carbide coating are combined to utilize the high thermal conductivity of graphite for rapid heat equalization, while the silicon carbide coating isolates the reaction chamber from graphite volatiles.

[0039] As a technical optimization of this utility model, a countersunk hole 6 is provided at the center of the lower end face of the tray base 1, and a threaded ceramic sleeve 7 is fixedly connected to the inner side of the countersunk hole 6.

[0040] In this embodiment: the countersunk hole 6 is embedded with a threaded ceramic sleeve 7, and the ceramic and the graphite matrix are thermally matched to avoid tray shaking caused by interface cracking during high-temperature rotation.

[0041] As a technical optimization of this utility model, the inner edge of the bottom support ring 3 is provided with a rounded corner structure with a rounded corner radius R≥0.5mm.

[0042] In this embodiment, the rounded corners on the inner side of the bottom support ring 3 eliminate stress concentration points in the coating, preventing the coating from cracking and peeling off from the sharp corners under cyclic thermal shock.

[0043] The working principle and usage process of this utility model are as follows: The wafer is placed on the bottom support ring 3 of the wafer carrier position 2. During the high-temperature process, the tray substrate 1 is heated to 1600°C. The reaction gas is injected from the top of the chamber and flows radially from the center of the tray to the outer edge along the radial guide groove 5. When it reaches the inclined transition surface 4, it wraps the bottom surface of the wafer upward along the polished inclined surface. When the wafer expands due to heat, the edge slides outward along the inclined transition surface 4. The rotating shaft drives the tray substrate 1 to rotate at a uniform speed through the threaded ceramic sleeve 7, so that each area of ​​the wafer is alternately exposed to the high-speed and low-speed airflow areas, thereby achieving dynamic balance of the growth rate. The silicon carbide coating completely covers the graphite substrate under the protection of the rounded corner structure, preventing the diffusion of substrate impurities into the reaction environment.

[0044] 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.

[0045] 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 tray structure for a silicon carbide epitaxial device, characterized in that: include: The tray base (1) has multiple wafer carrier positions (2) arranged in concentric circles on its upper end surface; Each of the wafer carrier sites (2) is a stepped recessed structure, including: A bottom support ring (3) is embedded in the upper end of the tray base (1); Inclined transition surface (4) connects the outer edge of the upper end face of the bottom support ring (3) with the upper surface of the tray base (1).

2. The tray structure for a silicon carbide epitaxial device according to claim 1, characterized in that: The inclined transition surface (4) has an inclination angle of 15°-45° and is polished.

3. The tray structure for a silicon carbide epitaxial device according to claim 1, characterized in that: The upper surface of the tray base (1) is provided with guide grooves (5) radially distributed with the center of the tray base (1) as the center. Multiple guide grooves (5) are staggered with multiple wafer carrier positions (2). The depth of the guide grooves (5) is 1-3mm and the width is 2-5mm.

4. The tray structure for a silicon carbide epitaxial device according to claim 1, characterized in that: The tray substrate (1) is made of high-purity graphite material and covered with a silicon carbide coating with a coating thickness of 50-200μm.

5. A tray structure for a silicon carbide epitaxial device according to claim 1, characterized in that: A countersunk hole (6) is provided at the center of the lower end face of the tray base (1), and a threaded ceramic sleeve (7) is fixedly connected to the inner side of the countersunk hole (6).

6. The tray structure for a silicon carbide epitaxial device according to claim 1, characterized in that: The bottom support ring (3) has a rounded corner structure on its inner edge, with a rounded corner radius R ≥ 0.5 mm.

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