A slide tray and epitaxial growth apparatus

Abstract

This application discloses a wafer carrier tray and an epitaxial growth apparatus, relating to the field of semiconductor epitaxial growth technology. By setting the first surface of the wafer carrier tray to support the wafer as a convex structure, the center of the wafer is in direct contact with the center of the first surface of the wafer carrier tray, while there is a gap between the periphery of the wafer and the periphery of the first surface of the wafer carrier tray. This results in the temperature at the periphery of the wafer being lower than the temperature at the center of the wafer, and consequently, the epitaxial growth rate at the periphery is lower than that at the center of the wafer. Ultimately, this yields an epitaxial wafer with a more stable thickness model during the epitaxial growth process, characterized by a higher center and lower edges. This reduces the impact of uneven density distribution of the wafer carrier tray and the wafer's own curvature on the thickness model of the epitaxial wafer, thereby reducing the probability of product scrap due to changes in the thickness model and improving the stability of the epitaxial growth process and product quality.

Description

Technical Field

[0001] This application relates to the field of semiconductor epitaxial growth technology, and in particular to a wafer tray and an epitaxial growth apparatus. Background Technology

[0002] In semiconductor epitaxial growth processes, wafers, such as SiC wafers, are typically placed on heated wafer trays. The trays transfer heat to the wafers, and epitaxial growth occurs under specific gas conditions to form epitaxial wafers. However, existing wafer trays are mostly designed for uniform thickness. Due to the uneven density distribution of the trays themselves, it is impossible to guarantee a completely uniform temperature distribution across the entire surface. This can lead to uneven heating of the wafers during epitaxial growth, resulting in inconsistent growth rates at different locations on the wafer surface. Furthermore, the thermal stress caused by this uneven temperature distribution can affect the curvature of the epitaxial wafer, leading to thickness model flipping and product scrap. This severely impacts the stability of the epitaxial growth process and product quality. Summary of the Invention

[0003] To address the aforementioned technical problems, this application provides a wafer tray and an epitaxial growth apparatus. By designing the wafer tray structure, the probability of product scrap caused by thickness model changes during epitaxial wafer growth is reduced, the thickness uniformity of the epitaxial wafer is improved, and thus the stability of the epitaxial growth process and product quality are enhanced.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] In a first aspect, this application provides a slide tray, including a tray body;

[0006] The tray body has a first surface for holding the wafer, and the first surface is convex.

[0007] Optionally, the height of the center position of the first surface protruding relative to the periphery of the first surface ranges from 0.1mm to 1mm, including the endpoint values.

[0008] Optionally, the first surface is a convex elliptical surface.

[0009] Optionally, the first surface includes a first region and a second region surrounding the first region;

[0010] The first region is a plane;

[0011] Along a radial direction away from the center of the first surface, the height of the second region gradually decreases relative to the first region.

[0012] Optionally, the first surface may further include a third region surrounding the second region;

[0013] The third region is a plane, and the first region is higher than the third region.

[0014] Optionally, along a radial direction away from the center of the first surface, the height of the second region decreases linearly or as a smooth curve relative to the height of the first region.

[0015] Optionally, the tray body further includes a second surface disposed opposite to the first surface, the second surface including a fourth region, a fifth region surrounding the fourth region, and a sixth region surrounding the fifth region;

[0016] The fourth region is a plane, the sixth region is a plane, and the sixth region is higher than the fourth region;

[0017] Along a radial direction away from the center of the second surface, the height of the fifth region gradually increases relative to the fourth region.

[0018] Optionally, the height difference between the fourth region and the sixth region is in the range of 0.5mm-1mm, including the endpoint values.

[0019] Optionally, the material of the slide tray is graphite or tantalum carbide;

[0020] Alternatively, the main material of the slide tray is graphite, and at least the first surface of the slide tray is coated with a tantalum carbide coating.

[0021] Secondly, this application provides an epitaxial growth apparatus, comprising: a wafer tray as described in any of the preceding claims, and a limiting ring;

[0022] The limiting ring is arranged around the wafer tray to fix the wafer tray and the wafer on the wafer tray.

[0023] Compared with existing technologies, the above technical solution has the following advantages:

[0024] The wafer carrier tray provided in this application includes a tray body with a first surface for supporting wafers. By setting the first surface as a convex structure, i.e., the center of the first surface is higher than its periphery, when the wafer is supported on the first surface of the wafer carrier tray, the center of the wafer is in direct contact with the center of the first surface of the wafer carrier tray, while there is a gap (i.e., non-direct contact) between the periphery of the wafer and the periphery of the first surface of the wafer carrier tray. Thus, the temperature of the center of the wafer is relatively higher due to direct contact with the wafer carrier tray, while the temperature of the periphery of the wafer is relatively lower due to non-direct contact with the wafer carrier tray. Consequently, the epitaxial growth rate of the periphery of the wafer is lower than that of the center of the wafer, making it easier to obtain an epitaxial wafer with a thickness model that is higher at the center and lower at the edge (positive curvature). The epitaxial wafer with a thickness model that is higher at the center and lower at the edge (positive curvature) is more stable during epitaxial growth. This reduces the probability of product scrap due to thickness model changes during epitaxial growth caused by uneven density distribution of the wafer carrier tray, improves the thickness uniformity of the epitaxial wafer, and thus improves the stability of the epitaxial growth process and product quality.

[0025] Furthermore, when a wafer with negative curvature is placed on the first surface of the wafer carrier provided in this application, because the first surface is convex and the wafer is thin and relatively soft, the center of the wafer with negative curvature will be lifted due to the higher center position of the first surface, thus the epitaxial wafer will grow with positive curvature during the epitaxial growth process. Conversely, when a wafer with positive curvature is placed on the first surface of the wafer carrier provided in this application, because the first surface is convex, the epitaxial wafer will maintain positive curvature during the epitaxial growth process. Since the internal stress of a wafer with positive curvature is mostly compressive stress, this stress state is more stable in a high-temperature epitaxial environment and is less prone to significant release or reconstruction. During epitaxial growth, the stress change trend is relatively predictable. After growing an epitaxial wafer of a certain thickness, only a regular increase in curvature will occur, rather than irregular deformation, ensuring that the epitaxial wafer grows stably at the rate expected by the model. Therefore, it can also reduce the impact of the wafer's own curvature on the epitaxial wafer thickness model and maintain the stability of the epitaxial wafer thickness model.

[0026] Furthermore, the wafer tray provided in this application is conducive to epitaxial growth of epitaxial wafers with a high center and low edge (positive curvature) thickness model, which can maintain the stability of the epitaxial wafer thickness model, reduce the frequency of epitaxial wafer thickness model flipping, and thus reduce the frequency of needle valve adjustment, avoiding the situation of pressure stagnation caused by frequent needle valve adjustment. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic cross-sectional view of a slide tray in the prior art;

[0029] Figure 2 In order to be in Figure 1 A magnified cross-sectional view of a wafer placed on a wafer tray, as shown.

[0030] Figure 3 This is a schematic diagram of the planar structure of a slide tray provided in an embodiment of this application;

[0031] Figure 4 for Figure 3 The diagram shows the structure of the slide tray along the CC' section.

[0032] Figure 5 This is a partial enlarged cross-sectional view of a substrate tray and epitaxial growth apparatus provided in an embodiment of this application.

[0033] Figure 6 This is a partial enlarged cross-sectional view of another substrate tray and epitaxial growth apparatus provided in an embodiment of this application;

[0034] Figure 7 for Figure 1 The thickness of two epitaxial wafers obtained after continuous epitaxial growth on an existing wafer carrier tray is shown at some locations.

[0035] Figure 8 for Figure 4 The illustration shows the thickness of some locations on two epitaxial wafers obtained after continuous epitaxial growth using the wafer tray provided in this embodiment of the application.

[0036] Explanation of reference numerals in the attached figures:

[0037] Wafer T; wafer tray 10; tray body 11; tray ring sheath 12; first surface S1; second surface S2; first region S11; second region S12; third region S13; fourth region S21; fifth region S22; sixth region S23; limiting ring 20; first limiting part 21; second limiting part 22. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0040] Figure 1 This is a schematic cross-sectional view of a slide tray 10 in the prior art. Figure 2 In order to be in Figure 1 A partially enlarged schematic diagram of the wafer T placed on the wafer tray 10 is shown below. Figure 1 and Figure 2 As shown, the existing wafer tray 10 is usually designed with uniform thickness, that is, the surface of the existing wafer tray 10 used to support the wafer T is a planar structure. In the figure, point A is the center position of the surface of the wafer tray 10 supporting the wafer T, and point B is the edge position of the surface of the wafer tray 10 supporting the wafer T. The heights of points A and B are the same. In this way, after the wafer T is placed on the surface of the wafer tray 10, all parts of the wafer T are in complete contact with the surface of the wafer tray 10.

[0041] However, as described in the background section, due to the uneven density distribution of the wafer tray itself, it is impossible to guarantee that the temperature distribution of each part of the wafer tray surface is completely consistent. Therefore, the wafer carried by the wafer tray may not be heated evenly during the epitaxial growth process, which may lead to inconsistent growth rates at different locations on the wafer surface. At the same time, the thermal stress generated by the uneven temperature may affect the curvature of the epitaxial wafer, resulting in the thickness of the epitaxial wafer flipping, causing product scrap and seriously affecting the stability of the epitaxial growth process and product quality.

[0042] The inventors also discovered that during continuous epitaxial mass production, the curvature of the wafers used initially is not completely consistent. Curvature (BOW) refers to the maximum deviation distance between the wafer center plane (i.e., the plane formed by the midpoint of the wafer thickness) and a reference plane in a free, unclamped state. It describes the overall macroscopic deformation of the wafer, which is "bowl-shaped" or "umbrella-shaped". Curvature can be positive or negative. Generally, a convex shape (i.e., the center of the wafer is higher than its edge) is positive, and a concave shape (i.e., the center of the wafer is lower than its edge) is negative. Therefore, during epitaxial growth, the curvature of the epitaxial wafer will change dynamically due to the influence of residual stress, which may also lead to changes in the thickness model of the epitaxial wafer and result in product scrap (i.e., thickness flip).

[0043] However, during high-temperature epitaxy, the release of tensile stress in wafers with negative curvature can induce lattice distortion and form a large number of extended defects. These defects can hinder the uniform adsorption and migration of atoms on the surface of the epitaxial wafer, causing significant fluctuations in the growth rate of the local epitaxial wafer. Consequently, during continuous growth, wafers with negative curvature are prone to thickness model changes, which seriously affect the stability of the epitaxial process and product quality control. On the other hand, the internal stress of wafers with positive curvature is mostly compressive stress. This stress state is more stable in the high-temperature epitaxial environment and is less prone to large-scale release or reconstruction. During epitaxial growth, the stress change trend is relatively predictable. After growing an epitaxial wafer of a certain thickness, only a regular increase in curvature will occur, rather than irregular deformation, which can ensure that the epitaxial wafer grows stably at the rate expected by the model.

[0044] Currently, considering that different needle valves are typically used to regulate the airflow at different locations on the epitaxial wafer within the epitaxial growth chamber, adjusting these needle valves can be used to control the continuous growth of epitaxial wafers with the target thickness model during the epitaxial growth process. Specifically, increasing the flow rate of the central needle valve in the corresponding central region of the epitaxial wafer can achieve an epitaxial wafer thickness model that is high in the center and low at the edges; conversely, decreasing the flow rate of the central needle valve in the corresponding central region can achieve an epitaxial wafer thickness model that is low in the center and high at the edges. However, frequent adjustment of the needle valves may lead to abnormal flow control, causing pressure buildup, affecting the airflow distribution within the growth chamber and resulting in uneven temperature distribution. This amplifies the impact of changes in the internal stress of the epitaxial wafer on atomic adsorption and migration, thereby affecting the thickness model of the epitaxial wafer and leading to product scrap.

[0045] To address the above problems, this application provides a slide tray 10. Figure 3 This is a schematic diagram of the planar structure of a slide tray 10 provided in an embodiment of this application. Figure 4 for Figure 3 The schematic diagram of the slide tray along the CC' section is shown below. Figure 3 and Figure 4As shown, the wafer carrier tray 10 includes a tray body 11, which has a first surface S1 for holding the wafer T. The first surface S1 is convex, meaning that the center of the first surface S1 (corresponding to point A in the figure) is higher than its periphery (corresponding to point B in the figure).

[0046] It is understandable that by setting the first surface S1 of the slide tray 10 to a convex structure, that is, the center position of the first surface S1 of the slide tray 10 is higher than its periphery, thus, the reference... Figure 5 and Figure 6 As shown, when wafer T is supported on the first surface S1 of wafer carrier tray 10, the center of the wafer is in direct contact with the center of the first surface S1 of wafer carrier tray 10, while the periphery of the wafer has a gap (i.e., not in direct contact) with the periphery of the first surface S1 of wafer carrier tray 10. Thus, the temperature of the center of the wafer is relatively high due to direct contact with the wafer carrier tray, while the temperature of the periphery of the wafer is relatively low due to not being in direct contact with the wafer carrier tray. Consequently, the epitaxial growth rate of the periphery of the wafer is lower than that of the center of the wafer, making it easier to obtain an epitaxial wafer with a thickness model that is high at the center and low at the edge (positive curvature). The epitaxial wafer with a thickness model that is high at the center and low at the edge (positive curvature) is more stable during epitaxial growth. This reduces the probability of product scrap due to thickness model changes during epitaxial growth caused by uneven density distribution of the wafer carrier tray, improves the thickness uniformity of the epitaxial wafer, and thus improves the stability of the epitaxial growth process and product quality.

[0047] It is also understood that when a wafer with negative curvature is placed on the first surface S1 of the wafer carrier 10 provided in this embodiment, reference... Figure 5 and Figure 6 As shown, since the first surface S1 is convex and the wafer is relatively thin and soft, the center of the wafer with negative curvature will be lifted due to the higher center of the first surface S1, resulting in positive curvature during epitaxial growth. When the wafer with positive curvature is placed on the first surface S1 of the wafer carrier 10 provided in this embodiment, since the first surface S1 is convex, the epitaxial wafer maintains positive curvature during epitaxial growth. Since the internal stress of the wafer with positive curvature is mostly compressive stress, this stress state is more stable in the high-temperature epitaxial environment and is less prone to significant release or reconstruction. During epitaxial growth, the stress change trend is relatively predictable. After growing an epitaxial wafer of a certain thickness, only a regular increase in curvature will occur, rather than irregular deformation, which can ensure that the epitaxial wafer grows stably at the rate expected by the model. Therefore, it can also reduce the impact of the wafer's own integrity on the epitaxial wafer thickness model and maintain the stability of the epitaxial wafer thickness model.

[0048] Furthermore, the wafer tray 10 provided in this application embodiment is conducive to epitaxial growth of epitaxial wafers with a center high and edge low (positive curvature) thickness model, which can maintain the stability of the epitaxial wafer thickness model, reduce the frequency of epitaxial wafer thickness model flipping, and thus reduce the frequency of needle valve adjustment, avoiding the situation of pressure stagnation caused by frequent needle valve adjustment.

[0049] Optionally, in some embodiments of this application, such as Figure 4 As shown, the height d1 of the protrusion of the center position (point A in the figure) of the first surface S1 of the wafer tray 10 relative to the peripheral position (point B in the figure) of the first surface S1 can be 0.1mm-1mm, including the endpoint value. In this way, the center position of the wafer T can be in direct contact with the center position of the first surface S1 of the wafer tray 10, while there is a gap between the peripheral position of the wafer T and the peripheral position of the first surface S1 of the wafer tray 10. This makes the epitaxial growth rate of the peripheral position of the wafer T lower than that of the center position of the wafer T, which makes it easier to obtain an epitaxial wafer with a thickness model that is high at the center and low at the edge (positive curvature). At the same time, it can also avoid the difference between the epitaxial growth rate of the center position of the wafer T and the epitaxial growth rate of the peripheral position of the wafer T being too large.

[0050] Regarding the specific morphology of the first surface S1 of the slide tray 10, optionally, in some embodiments of this application, such as Figure 4 As shown, the first surface S1 of the slide tray 10 can be a convex elliptical surface. That is, along the radial direction away from the center of the first surface S1, the height of the first surface S1 gradually decreases along a smooth curve.

[0051] It is understandable that when the wafer T is placed on the first surface S1 of the wafer carrier tray 10, which has a convex elliptical surface, the initial wafer thickness is relatively thin and the overall thickness is relatively soft. Therefore, even if the wafer has a negative curvature, its center position will be lifted by the center position of the first surface S1. Furthermore, along the radial direction away from the center position of the first surface S1, the vertical distance between the first surface S1 of the wafer carrier tray 10 and the wafer T gradually increases. Correspondingly, the temperature transferred from the wafer carrier tray 10 to the corresponding area of ​​the wafer T gradually decreases, and the growth rate of the corresponding area of ​​the epitaxial wafer gradually decreases, which is conducive to obtaining an epitaxial wafer with a more stable thickness model through epitaxial growth.

[0052] Regarding the specific morphology of the first surface S1 of the slide tray 10, another option, in some embodiments of this application, is as follows: Figure 5As shown, the first surface S1 of the slide tray 10 includes a first region S11 and a second region S12 surrounding the first region S11; the first region S11 is a plane; along the radial direction away from the center of the first surface S1, the height of the second region S12 gradually decreases relative to the first region S11. At this time, the second region S12 can extend from the first region S11 to the edge of the first surface S1, and the first surface S1 of the slide tray 10 can be an annular boss surface.

[0053] Understandably, by dividing the first surface S1 of the wafer carrier 10 into a first region S11 and a second region S12 surrounding the first region S11, the first region S11 is planar and its height is greater than that of the second region S12. Thus, the first region S11 directly contacts the wafer T, allowing the central region of the wafer T corresponding to the first region S11 to have a higher temperature, resulting in a higher epitaxial growth rate and improved support for the wafer T. Meanwhile, along the radial direction away from the center of the first surface S1, the height of the second region S12 gradually decreases, thereby gradually increasing the vertical distance between the second region S12 and the wafer T. Correspondingly, the temperature transmitted from the wafer carrier 10 to the corresponding region of the wafer T gradually decreases, and the growth rate of the corresponding region of the epitaxial wafer also gradually decreases. Ultimately, an epitaxial wafer with a relatively high central region and a gradually decreasing height of the surrounding region can be obtained.

[0054] Another option for the specific morphology of the first surface S1 of the slide tray 10 is, as follows: Figure 6 As shown, the first surface S1 of the slide tray 10 includes not only a first region S11 and a second region S12 surrounding the first region S11, but also a third region S13 surrounding the second region S12; the first region S11 is planar; the third region S13 is planar, and the first region S11 is higher than the third region S13; along the radial direction away from the center of the first surface S1, the height of the second region S12 relative to the first region S11 gradually decreases. In this case, the first surface S1 of the slide tray 10 can be an annular stepped surface.

[0055] It is understandable that by dividing the first surface S1 of the wafer carrier 10 into a first region S11, a second region S12 surrounding the first region S11, and a third region S13 surrounding the second region S12, both the first region S11 and the third region S13 are planar, and the height of the third region S13 is lower than that of the first region S11, the first region S11 still serves to support the wafer T and maintain a high epitaxial growth rate in the central region of the wafer T; the second region S12 serves as a transition region, causing the epitaxial growth rate of the corresponding position of the wafer T to gradually decrease in the radial direction away from the center position of the first surface S1; the third region S13 corresponds to the edge region of the wafer T. Since the third region S13 is planar and the gap distance between it and the edge region of the wafer T is relatively fixed, the epitaxial growth rate of the edge region of the wafer T is relatively fixed. Ultimately, an epitaxial wafer with a relatively high thickness in the central region and a relatively low thickness in the edge region, and a thickness that gradually decreases from the central region to the edge region, can be obtained.

[0056] Optional, such as Figure 5 and Figure 6 As shown, along the radial direction away from the center of the first surface S1, the height of the second region S12 relative to the first region S11 can be linear (e.g., ...). Figure 6 (as shown) or a smooth curve (such as) Figure 5 (As shown) The height of the second region S12 of the first surface S1 gradually decreases. However, this application does not limit the form in which the height of the second region S12 of the first surface S1 gradually decreases. In addition to linear decrease or decrease along a smooth curve, it can also be decreased in other forms. It is only necessary to ensure that the gap distance between the wafer tray 10 and the wafer T gradually increases in the radial direction away from the center position of the first surface S1, thereby ensuring that the epitaxial growth rate of the corresponding region of the wafer T gradually decreases and avoiding local abrupt changes in the thickness of the wafer T.

[0057] Based on any of the above embodiments, optionally, in some embodiments of this application, such as Figure 6 As shown, the tray body 11 of the slide tray 10 also includes a second surface S2 disposed opposite to the first surface S1. The second surface S2 includes a fourth region S21, a fifth region S22 surrounding the fourth region S21, and a sixth region S23 surrounding the fifth region S22. The fourth region S21 is planar, and the sixth region S23 is planar. The sixth region S23 is higher than the fourth region S21. Along the radial direction away from the center of the second surface S2, the height of the fifth region S22 relative to the fourth region S21 gradually increases. At this time, the second surface S2 of the slide tray 10 is an annular stepped surface.

[0058] It is understandable that a heating device is provided on one side of the second surface S2 of the wafer carrier tray 10. The second surface S2 of the wafer carrier tray 10 is heated and then the temperature is conducted to the wafer T through the first surface S1. The second surface S2 of existing wafer carrier trays is usually planar (see reference). Figure 5 (As shown in the second surface S2). In this embodiment, the second surface S2 of the wafer tray 10 is divided into a fourth region S21, a fifth region S22 surrounding the fourth region S21, and a sixth region S23 surrounding the fifth region S22. Both the fourth region S21 and the sixth region S23 are planar, and the sixth region S23 is higher than the fourth region S21. Thus, the fourth region S21 is lower in height and can directly contact the heating device located at the bottom of the wafer tray 10, resulting in a relatively higher temperature in the fourth region S21. Correspondingly, the temperature of the corresponding region of the first surface S1 (e.g., the first region S11) is relatively higher, thereby resulting in a relatively higher temperature in the central region of the wafer T, leading to a larger epitaxial growth rate. Along the center position away from the second surface S2 In the radial direction, the height of the fifth region S22 gradually increases relative to the height of the fourth region S21, thus the distance between the fifth region S22 and the heating device gradually increases, and the temperature of the fifth region S22 gradually decreases. Correspondingly, the temperature of the corresponding region of the first surface S1 (e.g., the second region S12) gradually decreases, thereby causing the temperature of the corresponding region of the wafer T to gradually decrease, and the epitaxial growth rate to gradually decrease. The sixth region S23 is planar, so the distance between the sixth region S23 and the heating device is relatively fixed, making the temperature of the sixth region S23 relatively fixed. Correspondingly, the temperature of the corresponding region of the first surface S1 (e.g., the third region S13) is relatively fixed, thereby making the temperature of the edge region of the wafer T relatively fixed, maintaining a stable epitaxial growth rate.

[0059] In other words, this embodiment not only uses the design of the first surface S1 of the wafer tray 10 as a convex structure, but also uses the design of the annular stepped surface of the second surface S2 of the wafer tray 10, which has a low center area and a high edge area, in order to make the temperature conducted to the center area of ​​the wafer T relatively high, maintaining a high epitaxial growth rate, while the temperature conducted to the peripheral area of ​​the wafer T relatively low, maintaining a low epitaxial growth rate, and finally easily obtaining an epitaxial wafer with a thickness model that is high in the center and low at the edge (positive curvature).

[0060] It should be noted that when the second surface S2 of the slide tray 10 is adopted as... Figure 6 When the annular stepped surface structure is shown, the first surface S1 of the slide tray 10 can also be adopted. Figure 6 The annular stepped surface structure shown is not limited to this in this application. Alternatively, the first surface S1 of the slide tray 10 may also adopt other alternatives. Figure 5 The annular boss surface structure shown, or using Figure 4The convex elliptical surface structure shown may vary depending on the specific circumstances.

[0061] It should also be noted that, in the various embodiments of this application, the height of each position on the first surface S1 and the second surface S2 is compared in the vertical direction from the second surface S2 to the first surface S1.

[0062] Optionally, in the second surface S2 of the wafer tray 10, the height difference between the fourth region S21 and the sixth region S23 can be in the range of 0.5mm-1mm, including the endpoint value, so that the epitaxial growth rate at the periphery of the wafer T is lower than the epitaxial growth rate at the center of the wafer T, making it easier to obtain an epitaxial wafer with a thickness model that is high at the center and low at the edge (positive curvature), while also avoiding an excessive difference between the epitaxial growth rate at the center of the wafer T and the epitaxial growth rate at the periphery of the wafer T.

[0063] Based on any of the above embodiments, optionally, in some embodiments of this application, the material of the wafer carrier 10 can be graphite or tantalum carbide. It is understood that graphite has excellent high-temperature resistance and high thermal conductivity, making it a preferred material for the wafer carrier 10. However, after a period of use, graphite powder may detach from the surface of the graphite wafer carrier, leading to abnormal particle formation in the epitaxially grown wafer. Therefore, tantalum carbide can also be selected as the material for the wafer carrier 10. Tantalum carbide has superior high-temperature resistance and thermal stability, as well as a certain degree of corrosion resistance, which can reduce powder detachment from the wafer carrier 10 during the epitaxial process and lower the probability of abnormal particle formation in the epitaxial wafer.

[0064] Alternatively, in some embodiments of this application, the main material of the wafer tray 10 is graphite, and at least the first surface S1 of the wafer tray 10 is coated with a tantalum carbide coating. Thus, the tantalum carbide coating on at least the first surface S1 of the wafer tray 10 can prevent graphite powder from detaching, which helps to prevent detached graphite powder from entering the epitaxial wafer and causing particle abnormalities. Specifically, the tantalum carbide coating can be applied only to the first surface S1 of the wafer tray 10, or it can be applied to the entire surface of the wafer tray 10. It is understood that applying a tantalum carbide coating to the entire surface of the wafer tray 10 provides a better effect in preventing graphite powder from detaching and entering the epitaxial wafer, thus further preventing particle abnormalities.

[0065] Accordingly, embodiments of this application also provide an epitaxial growth apparatus, such as... Figure 5 and Figure 6As shown, the epitaxial growth apparatus includes a wafer tray 10 provided in any of the preceding embodiments, and a limiting ring 20; the limiting ring 20 is disposed around the wafer tray 10 and is used to fix the wafer tray 10 and the wafer T located on the wafer tray 10.

[0066] It is understood that the wafer tray 10 includes a tray body 11 and a tray ring sheath 12, with the tray ring sheath 12 surrounding the tray body 11. The limiting ring 20 includes a first limiting part 21 and a second limiting part 22. The shape of the second limiting part 22 is adapted to the tray body 11 and the tray ring sheath 12 to fix the position of the wafer tray 10. The shape of the first limiting part 21 is adapted to the shape of the wafer T to fix the wafer T. The height of the first limiting part 21 needs to be adjusted accordingly based on the wafer tray 10 to ensure that the height of the contact surface between the first limiting part 21 and the wafer T is greater than or equal to the height of the wafer T placed in the wafer tray 10, thus preventing the epitaxial wafer from shifting or flying off during subsequent production. Through the above device, the wafer tray 10 and the wafer T can be fixed in the epitaxial growth apparatus, preventing changes in the position of the wafer or wafer tray during the epitaxial growth process from affecting the epitaxial growth quality.

[0067] Figure 7 It shows Figure 1 The thickness of two epitaxial wafers (marked as before and after flipping) obtained after continuous epitaxial growth on the existing wafer tray is shown. It can be seen that although both epitaxial wafers are of the same thickness model with a lower center and a higher edge, the abnormal wafer (marked as the epitaxial wafer after flipping) has a lower center thickness and a higher edge thickness. The uniformity changes from 1.32% (marked as the epitaxial wafer before flipping) to 3.33% (marked as the epitaxial wafer after flipping).

[0068] Figure 8 It shows Figure 4 The thickness of two epitaxial wafers (marked as before and after flipping) obtained after continuous epitaxial growth on the wafer tray 10 provided in the embodiment of this application is shown. It can be seen that the thickness model changes from a center-low and edge-high model to a center-high and edge-low model, and the uniformity changes only from 0.75% (marked as the epitaxial wafer after flipping) to 1.58% (marked as the epitaxial wafer before flipping).

[0069] contrast Figure 7 and Figure 8 Experimental results show that using the slide tray provided in this application significantly reduces the amount of thickness uniformity variation caused by changes in the thickness model, thereby reducing the product defect rate due to changes in the thickness model. Furthermore, for thickness models with a high center and low edges, using the slide tray provided in this application can reduce the thickness variation anomaly rate to 1%.

[0070] In summary, the wafer carrier tray and epitaxial growth apparatus provided in this application embodiment, by setting the first surface of the wafer carrier tray to carry the wafer as a convex structure, allows the center of the wafer to directly contact the center of the first surface of the wafer carrier tray, while the periphery of the wafer has a gap (i.e., non-direct contact) with the periphery of the wafer. This results in a lower epitaxial growth rate at the periphery of the wafer compared to the center, ultimately making it easier to obtain an epitaxial wafer with a thickness model that is higher at the center and lower at the edges (positive curvature). Epitaxial wafers with a thicker thickness model are more stable during epitaxial growth, thereby reducing the probability of product scrap due to thickness model changes during epitaxial growth caused by uneven density distribution of the wafer carrier tray, improving the thickness uniformity of the epitaxial wafer, and thus improving the stability of the epitaxial growth process and product quality. At the same time, it can also reduce the impact of the wafer's own integrity on the epitaxial wafer thickness model, maintaining the stability of the epitaxial wafer thickness model; and it can also reduce the frequency of needle valve adjustment, reducing the pressure buildup problem caused by frequent needle valve adjustments. In addition, the epitaxial growth apparatus can also ensure that the wafer tray and wafer are fixed during the epitaxial growth process, avoiding positional displacement or wafer slippage that would affect the quality of the epitaxially grown wafer and the epitaxial growth efficiency.

[0071] The various parts of this manual are described in a combination of parallel and progressive methods. Each part focuses on the differences between the other parts, and the same or similar parts can be referred to each other.

[0072] The features described above regarding the disclosed embodiments can be substituted or combined with each other to enable those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A slide tray, characterized in that, Including the tray body; The tray body has a first surface for holding the wafer, and the first surface is convex.

2. The slide tray according to claim 1, characterized in that, The height of the center position of the first surface protruding relative to the periphery of the first surface ranges from 0.1mm to 1mm, including the endpoint values.

3. The slide tray according to claim 1, characterized in that, The first surface is a convex elliptical surface.

4. The slide tray according to claim 1, characterized in that, The first surface includes a first region and a second region surrounding the first region; The first region is a plane; Along a radial direction away from the center of the first surface, the height of the second region gradually decreases relative to the first region.

5. The slide tray according to claim 4, characterized in that, The first surface also includes a third region surrounding the second region; The third region is a plane, and the first region is higher than the third region.

6. The slide tray according to claim 4 or 5, characterized in that, Along a radial direction away from the center of the first surface, the height of the second region decreases linearly or as a smooth curve relative to the height of the first region.

7. The slide tray according to any one of claims 3-5, characterized in that, The tray body also includes a second surface disposed opposite to the first surface, the second surface including a fourth region, a fifth region surrounding the fourth region, and a sixth region surrounding the fifth region; The fourth region is a plane, the sixth region is a plane, and the sixth region is higher than the fourth region; Along a radial direction away from the center of the second surface, the height of the fifth region gradually increases relative to the fourth region.

8. The slide tray according to claim 7, characterized in that, The height difference between the fourth region and the sixth region ranges from 0.5mm to 1mm, including the endpoint values.

9. The slide tray according to claim 1, characterized in that, The material of the slide tray is graphite or tantalum carbide; Alternatively, the main material of the slide tray is graphite, and at least the first surface of the slide tray is coated with a tantalum carbide coating.

10. An epitaxial growth apparatus, characterized in that, include: The slide tray as described in any one of claims 1-9, and the limiting ring; The limiting ring is arranged around the wafer tray to fix the wafer tray and the wafer on the wafer tray.

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