Sample tank for bearing wafer and epitaxial base

Abstract

The invention relates to a sample tank for bearing a wafer and an epitaxial base, the sample tank comprises a groove for bearing the wafer, the bottom of the groove comprises a wafer supporting surface, and the side wall of the groove comprises a fence structure; the enclosure structure comprises a straight enclosure which is arranged corresponding to the reference edge of the wafer; the arc enclosure is arranged corresponding to the arc part of the wafer; the transition fence is arranged between the straight fence and the arc fence, and the transition fence comprises an external corner area directly connected with the straight fence and an internal corner area directly connected with the arc fence; the straight fence and the transition fence are both located in the circumference where the arc fence is located. The enclosure structure comprises the straight enclosure, the arc enclosure and the transition enclosure, the transition enclosure comprises the external corner area and the internal corner area, and the straight enclosure and the transition enclosure are both located in the circumference where the arc enclosure is located, so that abrasion of geometric sharp positions such as the tail end of a wafer reference edge to the sample groove enclosure is reduced, and the service life of the epitaxial base is prolonged.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a sample slot and epitaxial substrate for supporting wafers. Background Technology

[0002] In recent years, the semiconductor industry has developed rapidly, with device feature sizes continuously shrinking and integration and complexity increasing. Against this backdrop, unprecedentedly stringent requirements have been placed on the quality and performance of semiconductor wafer materials themselves, as well as the precision of fabrication processes. Forming an epitaxial layer on the wafer has become an indispensable key process step in advanced semiconductor manufacturing.

[0003] Taking metal-organic chemical vapor deposition (MOCVD) as an example, in the process of fabricating semiconductor epitaxial layers, the substrate wafer needs to be placed in the sample pocket of the epitaxial substrate. However, the sample pocket is usually circular. For wafers with reference edges, the shape of the sample pocket and the wafer does not match, making it easy for collisions to occur between the wafer and the sample pocket. In addition, since the geometric features of the wafer reference edge are relatively sharp, there is also a risk of accidental collisions between the wafer and the sample pocket during wafer handling or substrate rotation.

[0004] Since the hardness of a wafer is usually higher than that of a sample tank, when a collision occurs between the wafer and the sample tank, the coating on the surface of the epitaxial substrate is damaged, and the epitaxial substrate is corroded in the MOCVD process, leading to the failure of the epitaxial substrate. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a sample slot for supporting wafers, comprising:

[0006] The groove is used to support the wafer. The bottom of the groove includes a wafer support surface, and the sidewalls of the groove include a retaining structure.

[0007] The fencing structure includes:

[0008] A straight barrier is set to correspond to the reference edge of the wafer;

[0009] The arc-shaped enclosure is set to correspond to the arc-shaped portion of the wafer;

[0010] Transition fencing is set between straight fencing and curved fencing. Transition fencing includes the external corner area that is directly connected to the straight fencing and the internal corner area that is directly connected to the curved fencing.

[0011] Both the straight fencing and the transition fencing are located within the circumference of the curved fencing.

[0012] In one embodiment, the length of the straight barrier is less than the length of the reference edge of the wafer, and the straight barrier is used to conform to the middle portion of the reference edge of the wafer; the length of the straight barrier ranges from 80% to 90% of the length of the reference edge of the wafer.

[0013] In one embodiment, the bottom of the groove further includes an edge channel, which is disposed at the edge of the wafer support surface and at the junction of the wafer support surface and the arc-shaped enclosure.

[0014] In one embodiment, the bottom of the groove further includes a stress relief channel, which is disposed in the central region of the wafer support surface. The center of the stress relief channel coincides with the center of the edge channel, and the radius of the stress relief channel is 1 / 3 to 2 / 3 of the radius of the edge channel.

[0015] In one embodiment, the central angle of the edge channel ranges from 310° to 328°, the stress relief channel is annular, the groove is used to support the 4-inch wafer, the inner diameter of the edge channel ranges from 92mm to 98mm, the inner diameter of the stress relief channel ranges from 46mm to 56mm, the difference between the inner and outer diameters of the edge channel ranges from 1mm to 4mm, and the difference between the inner and outer diameters of the stress relief channel ranges from 1mm to 4mm.

[0016] In one embodiment, the height of the enclosure structure ranges from 0.5mm to 5mm, the bottom surface of the edge channel is lower than the wafer support surface by a height range of 0.5mm to 2mm, and the bottom surface of the stress relief channel is lower than the wafer support surface by a height range of 0.5mm to 2mm.

[0017] In one embodiment, the external corner area is a rounded corner area, and the transition fence includes a transition arc. The first end of the transition arc is tangent to the straight fence to form the external corner area, and the second end of the transition arc intersects with the arc fence to form the internal corner area. The diameter of the transition arc ranges from 1 mm to 3 mm.

[0018] In one embodiment, the wafer support surface is directly connected to the flat enclosure.

[0019] Another aspect of this application provides an epitaxial substrate for supporting a wafer, including the sample slot for supporting a wafer in any of the above embodiments.

[0020] In one embodiment, the epitaxial substrate for supporting the wafer includes a graphite substrate and a silicon carbide coating covering the surface of the graphite substrate.

[0021] The sample slot and epitaxial substrate for supporting wafers provided by the present invention, by including a straight barrier corresponding to the reference edge of the wafer, an arc barrier corresponding to the arc portion of the wafer, and a transition barrier between the straight barrier and the arc barrier, wherein the transition barrier includes a positive corner area and a negative corner area, and both the straight barrier and the transition barrier are located within the circumference of the arc barrier, reduces wear on the sample slot barrier at geometrically sharp points such as the end of the wafer reference edge, and extends the service life of the epitaxial substrate. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1 A top view of a sample slot for carrying a wafer according to an embodiment of this application is shown;

[0024] Figure 2 A cross-sectional schematic diagram of a sample slot for carrying a wafer is shown according to an embodiment of this application;

[0025] Figure 3 A schematic diagram is shown of the point contact between the enclosure structure and the wafer when the enclosure structure does not have a straight enclosure.

[0026] Figure 4 A schematic diagram of the enclosure structure without a transition enclosure is shown;

[0027] Figure 5 A schematic diagram is shown showing the contact between the transition enclosure and the wafer forming point when the transition enclosure is not located within the circumference of the arc enclosure;

[0028] Figure 6 This diagram illustrates the embedding of the wafer reference edge into the channel when a channel is provided at the junction of the wafer support surface and the flat enclosure.

[0029] Figure Labels

[0030] 100, Groove 110, Wafer Support Surface

[0031] 111. Edge channel; 112. Stress relief channel

[0032] 120. Fence structure; 121. Straight fence

[0033] 122. Curved fence; 123. Transition fence

[0034] 1231. External corner area; 1232. Internal corner area Detailed Implementation

[0035] To better understand the above-mentioned objectives, features, and advantages of this application, embodiments of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0036] Numerous specific details are set forth in the following description to provide a thorough understanding of this application, but this application may also be implemented in other ways than those described herein. Clearly, the embodiments described in the specification are only a portion of, and not all, of the embodiments of this application.

[0037] In the fabrication of semiconductor epitaxial layers, a substrate wafer must be placed within the sample pocket of the epitaxial substrate. The wafer typically has a reference flat (also called a positioning edge), the ends of which have relatively sharp geometric features. Therefore, collisions are prone to occur between the wafer and the sample pocket. When a collision occurs, the coating on the surface of the epitaxial substrate is damaged, and the epitaxial substrate is etched during the MOCVD process, leading to substrate failure.

[0038] To address the aforementioned problems, this application provides a sample slot for supporting wafers, with reference to... Figure 1 and Figure 2 As shown, it includes:

[0039] The groove 100 is used to support the wafer. The bottom of the groove 100 includes a wafer support surface 110, and the sidewalls of the groove include a retaining structure 120.

[0040] The enclosure structure 120 includes:

[0041] The straight enclosure 121 is set to correspond to the reference edge of the wafer;

[0042] The arc-shaped enclosure 122 is set to correspond to the arc portion of the wafer;

[0043] The transition fence 123 is set between the straight fence 121 and the arc fence 122. The transition fence 123 includes a positive corner area 1231 that is directly connected to the straight fence 121 and a negative corner area 1232 that is directly connected to the arc fence 122.

[0044] Both the straight fence 121 and the transition fence 123 are located within the circumference of the arc fence 122.

[0045] In one embodiment, a groove 100 is formed in the epitaxial substrate as the main structure of a sample slot for supporting a wafer. The bottom of the groove 100 is a plane for supporting the wafer, referred to as the wafer support surface 110. The sidewalls of the groove 100 surround the wafer and are referred to as the enclosure structure 120. The height of the enclosure structure 120 is the depth of the groove 100, which is the height of the wafer support surface 110 below the surface of the non-groove area of ​​the epitaxial substrate. Furthermore, the height of the enclosure structure 120 is typically greater than the thickness of the wafer to ensure that the wafer is completely contained within the groove 100. Specifically, the height of the enclosure structure 120 ranges from 0.5 mm to 5 mm, for example, 0.5 mm, 1 mm, 2 mm, 3 mm, and 5 mm.

[0046] In one embodiment, the enclosure structure 120 includes a straight enclosure 121 disposed corresponding to the reference edge of the wafer. The wafer reference edge, also known as the wafer positioning edge, is an important feature used to determine the wafer orientation during wafer manufacturing, playing a crucial role in wafer processing, alignment, and inspection. The wafer reference edge refers to the straight portion on the outer edge of the wafer, used to mark a specific orientation of the wafer. During wafer processing and handling, it helps guide the correct placement of the wafer in the equipment, ensuring proper alignment. Furthermore, silicon crystal structures with different crystal orientations differ in physical and electrical properties; therefore, the wafer reference edge can also be used to indicate specific crystal orientations, for example... <100> Crystal orientation. Wafer reference edges can also be used as alignment marks in alignment operations to ensure processing accuracy. Currently, wafer reference edges are mainly found on small-sized wafers, such as 2-inch wafers, 4-inch wafers, and some 6-inch wafers, while wafers of 6 inches and larger typically use V-grooves (notches) for positioning. Therefore, the sample slots provided in this application are typically used to support small-sized wafers; the following explanation uses a 4-inch wafer as an example.

[0047] For wafers with reference edges, when the sample slot enclosure structure is circular and does not have a straight enclosure, such as Figure 3 As shown, after wafer W is placed in the sample well, the corner of the reference edge makes point contact with the circular barrier A, which accelerates the wear rate of the sample well barrier. Therefore, it is necessary to install a straight barrier in the sample well used to support wafers with reference edges to avoid point contact between the corner of the wafer reference edge and the barrier structure of the sample well.

[0048] In one embodiment, the length of the straight barrier 121 is less than the length of the reference edge of the wafer. For example, the length of the straight barrier 121 is 80% to 90% of the length of the reference edge of the wafer, so that the straight barrier 121 is used to fit the middle part of the reference edge of the wafer and avoids the straight barrier 121 from contacting the corner part of the reference edge of the wafer.

[0049] In one embodiment, the enclosure structure 120 further includes an arc-shaped enclosure 122 corresponding to the arc portion of the wafer. Further, a transition enclosure 123 is provided between the straight enclosure 121 and the arc-shaped enclosure 122. The transition enclosure 123 is used to prevent the corner portion of the wafer reference edge from forming point contact with the enclosure structure 120. Specifically, transition enclosures 123 are provided at both ends of the straight enclosure 121, and the transition enclosures 123 at both ends of the straight enclosure 121 are symmetrically arranged.

[0050] When straight and curved fences are directly connected without a transition fence, the resulting structure is as follows: Figure 4 As shown, a sharp external angle B is formed at the junction of the straight and curved barriers. This allows the wafer to be placed... Figure 4 During the epitaxial process in the sample holder shown, rotation causes significant stress at the sharp corner B, making this area prone to wear. Therefore, for sample holders supporting wafers with reference edges, it is necessary to round the corners on both sides of the straight enclosure to avoid stress concentration caused by sharp corners.

[0051] In one embodiment, the transition fence 123 includes an external corner region 1231 directly connected to the straight fence 121, and an internal corner region 1232 directly connected to the curved fence 122. (See reference...) Figure 1 As shown, the transition enclosure 123 includes a transition arc. The first end of the transition arc is tangent to the straight enclosure 121 to form a positive corner area 1231, and the second end of the transition arc intersects with the arc enclosure 122 to form a negative corner area 1232. In order to achieve the connection between the two ends of the transition arc and the straight enclosure 121 and the arc enclosure 122 respectively, the diameter of the transition arc must be greater than or equal to the minimum distance between the straight enclosure 121 and the arc enclosure 122, and the center of the transition arc must be located outside the groove 100, that is, the center of the transition arc is located on the side of the straight enclosure 121 away from the arc enclosure 122. The diameter range of the transition arc can be set as needed, for example, 1mm to 3mm. Optionally, the radius of the positive corner area 1231 formed by the transition arc and the straight enclosure 121 is 1mm.

[0052] In one embodiment, the positive corner region 1231 is a rounded corner region to avoid forming sharp protrusions in the enclosure structure 120. Specifically, the shape of the positive corner region 1231 is formed by the first end of the transition arc tangent to the straight enclosure 121; the shape of the negative corner region 1232 is formed naturally during processing by the second end of the transition arc and the end of the arc enclosure 122. The straight corner enclosure 121 and the arc enclosure 122 together restrict the movement space of the wafer, and the negative corner region 1232 can prevent the sharp part of the wafer reference edge from directly contacting the enclosure structure 120. Furthermore, the included angle of the negative corner region 1232 is related to the diameter of the transition arc. When the diameter of the transition arc increases, the included angle of the negative corner region 1232 increases, and when the diameter of the transition arc decreases, the included angle of the negative corner region 1232 decreases.

[0053] In one embodiment, both ends of the straight-corner fence 121 are connected to the arc-shaped fence 122 via a positive corner region 1231 and a negative corner region 1232, respectively. The positive corner region 1231 and the negative corner region 1232 form a transition fence 123 between the straight fence 121 and the arc-shaped fence 122, and the transition fences 123 at both ends of the straight fence 121 are symmetrically arranged. Optionally, the distance between the two negative corners, that is, the distance between the intersection points of the transition arcs on both sides of the straight-corner fence 121 and the arc-shaped fence 122, ranges from 25mm to 30mm, preferably 27.3mm.

[0054] The transition arc forms the positive corner region 1231 and the negative corner region 1232 as the transition barrier 123 between the flat corner barrier 121 and the arc barrier 122, avoiding direct contact between the sharp part of the wafer reference edge and the sample slot barrier structure, and reducing the number of times the sharp part of the wafer reference edge wears on the sample slot barrier during wafer handling or epitaxial substrate rotation.

[0055] It should be noted that both the straight fencing 121 and the transition fencing 123 are located within the circumference of the arc-shaped fencing 122. When the transition fencing adopts... Figure 5 In the design of the reserved space shown, the edge lines of the transition enclosure are all set in a direction away from the wafer, leaving space to avoid contact with the sharp parts of the wafer reference edge. The reserved space can be Figure 5 The superior arc-shaped sector region C is shown. Although... Figure 5 The fan-shaped enclosure shown serves as a transition barrier to prevent direct contact between the reference edge corner of the wafer and the sample well enclosure. However, due to slippage, the reference edge corner of the wafer W may extend into the curved fan-shaped area C, resulting in point contact. If the epitaxial process experiences a significant temperature increase at this point, the sample well is prone to localized cracking due to wafer thermal expansion. To avoid... Figure 5In the event of the situation shown, it is necessary to ensure that the graphic edge line of the fence structure 120 does not exceed the circumference of the arc fence 122. Therefore, the graphic edge lines of the straight fence 121 and the transition fence 123 must fall within the circumference of the arc fence 122.

[0056] In one embodiment, refer to Figure 1 and Figure 2 As shown, the bottom of the groove 100 is further provided with an edge channel 111 and a stress relief channel 112. The bottom surfaces of both the edge channel 111 and the stress relief channel 112 are lower than the wafer support surface 110. The depth of the edge channel 111, i.e., the height of its bottom surface below the wafer support surface 110, ranges from 0.5mm to 2mm, and is typically greater than 1mm; the depth of the stress relief channel 112, i.e., the height of its bottom surface below the wafer support surface, also ranges from 0.5mm to 2mm. The depths of the edge channel 111 and the stress relief channel 112 can be the same or different. In the embodiments of this application, the height of the bottom surface of the edge channel 111 below the wafer support surface 110 is 2mm, and the height of the bottom surface of the stress relief channel 112 below the wafer support surface is 1mm.

[0057] In one embodiment, the edge channel 111 is disposed at the edge of the wafer support surface 110, specifically at the junction of the wafer support surface 110 and the arc-shaped barrier 122. The edge channel 111 includes opposing sidewalls, wherein the outer sidewall of the edge channel 111 is connected to the surface of the arc-shaped barrier 122 to form the same surface, such as... Figure 2 As shown. By forming the edge channel 111, the contact area between the wafer and the arc enclosure 122 is changed from the right-angled area formed by the junction of the wafer support surface 110 and the arc enclosure 122 to the same surface formed by the connection of the edge channel 111 and the arc enclosure 122. This can greatly reduce the direct contact between the wafer and the sample well enclosure and avoid collisions and wear.

[0058] In one embodiment, the edge channel 111 is only provided at the junction of the wafer support surface 110 and the arc-shaped barrier 122. It should be noted that no edge channel is provided at the junction of the wafer support surface 110 and the flat barrier 121; the wafer support surface 110 and the flat barrier 121 are directly connected. Therefore, the edge channel 111 is arc-shaped rather than circular, as shown below. Figure 1 As shown. Specifically, the central angle of the edge channel 111 ranges from 310° to 328°, for example, 322°. Taking a 4-inch wafer as an example, the inner diameter of the edge channel ranges from 92mm to 98mm, for example, 98mm, and the difference between the inner and outer diameters of the edge channel ranges from 1mm to 4mm, for example, 1mm, 2mm, 3mm, 4mm.

[0059] When a trench is formed at the junction of the wafer support surface 110 and the flat barrier 121, a straight trench D will be formed, as shown in the figure. Figure 6 As shown, when wafer W is placed, the reference edge is easily embedded in the straight channel D. During the subsequent wafer leveling process, the embedded portion of the wafer will continuously squeeze and scrape the straight barrier area over a large area, leading to an accelerated wear rate in that area. The edge channel 111, located at the junction of the wafer support surface 110 and the arc barrier 122, has a curvature, which can prevent the wafer reference edge from embedding. Therefore, the edge channel 111 is only provided at the junction of the wafer support surface 110 and the arc barrier 122; no channel is provided at the junction of the wafer support surface 110 and the straight barrier 121.

[0060] In one embodiment, since wafer epitaxial growth is usually carried out in a high-temperature environment, reaching 1000°C or even higher, if the sample groove deforms due to thermal stress concentration, the deformed sample groove is prone to squeezing and rubbing against the wafer. Therefore, it is necessary to provide a stress relief channel 112 at the bottom of the groove 100 to prevent the sample groove from deforming due to thermal expansion and contraction, and to prevent the sharp part of the wafer reference edge from embedding into the sample groove enclosure.

[0061] In one embodiment, the stress relief channel 112 is disposed in the central region of the wafer support surface 110, and the center of the stress relief channel 112 coincides with the center of the edge channel 111. Specifically, the center of the stress relief channel 112, the center of the edge channel 111, and the center of the arc-shaped barrier 122 all coincide. The radius of the stress relief channel 112 is 1 / 3 to 2 / 3 of the radius of the edge channel 111. Taking a 4-inch wafer as an example, the inner diameter of the stress relief channel 112 ranges from 46 mm to 56 mm, and the difference between the inner diameter and the outer diameter of the stress relief channel 112 ranges from 1 mm to 4 mm. For example, when the inner diameter of the stress relief channel 112 is 50 nm and the difference between the inner diameter and the outer diameter is 4 mm, the outer diameter of the stress relief channel 112 is 54 nm.

[0062] In one embodiment, the process of placing the wafer in the sample cell includes: first, using a vacuum pen to hold the central area of ​​the back side of the wafer, so that the angle between the wafer plane and the wafer support surface 110 of the sample cell is less than 30°, aligning the wafer reference edge with and fitting it against the straight barrier 121 of the sample cell to avoid point contact between the wafer and the barrier structure 120 of the sample cell; then, releasing the vacuum of the vacuum pen, supporting the wafer solely by the support of the vacuum pen and continuously sliding the vacuum pen to the edge of the wafer, while continuously reducing the angle between the wafer plane and the wafer support surface 110 until the angle is less than 5°; finally, removing the vacuum pen from the edge of the wafer, allowing the wafer to fall naturally into the sample cell, thus completing the wafer placement operation.

[0063] This application also provides an epitaxial substrate for supporting wafers, which includes the sample slots described above for supporting wafers.

[0064] In one embodiment, the epitaxial substrate includes a graphite substrate and a silicon carbide (SiC) coating covering the surface of the graphite substrate. The SiC coating is mainly used to isolate the graphite substrate from direct contact with active gases (e.g., ammonia) in the chemical vapor deposition chamber, preventing the graphite substrate from being chemically corroded during high-temperature processes. Wafers are typically made of materials such as gallium arsenide (GaAs), aluminum oxide (Al2O3), silicon carbide (SiC), or silicon (Si). The hardness of the wafer is much higher than that of the graphite substrate. Therefore, when the wafer collides or is squeezed against the epitaxial substrate, it can cause localized deformation of the graphite substrate. Furthermore, the SiC coating covering the surface of the graphite substrate is typically thin, for example, 0.1 mm. Therefore, when the wafer collides or is squeezed against the epitaxial substrate, it can also cause damage to the SiC coating, leading to the failure of the graphite substrate. By adopting the above-described sample groove design for supporting the wafer in the epitaxial substrate, squeezing or collision between the wafer and the epitaxial substrate can be minimized, extending the service life of the epitaxial substrate.

[0065] The sample slot and epitaxial substrate for supporting wafers provided by the present invention, by including a straight barrier corresponding to the reference edge of the wafer, an arc barrier corresponding to the arc portion of the wafer, and a transition barrier between the straight barrier and the arc barrier, wherein the transition barrier includes a positive corner area and a negative corner area, and both the straight barrier and the transition barrier are located within the circumference of the arc barrier, reduces wear on the sample slot barrier at geometrically sharp points such as the end of the wafer reference edge, and extends the service life of the epitaxial substrate.

[0066] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0067] The above description is merely an embodiment of this application, which enables those skilled in the art to understand and implement this application. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may 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 described herein, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

1. A sample tank for carrying a wafer, characterized by, The application relates to a sample groove for carrying a wafer. The groove comprises a bottom and a sidewall, wherein the bottom comprises a wafer support surface and the sidewall comprises a surrounding structure. The surrounding structure comprises: a flat surrounding corresponding to a reference edge of the wafer; a circular surrounding corresponding to a circular part of the wafer; a transition surrounding arranged between the flat surrounding and the circular surrounding, wherein the transition surrounding comprises a convex corner region directly connected to the flat surrounding and a concave corner region directly connected to the circular surrounding; and wherein the flat surrounding and the transition surrounding are located within a circle of the circular surrounding.

2. The sample holder for carrying a wafer according to claim 1, wherein, The length of the flat surrounding is less than the length of the reference edge of the wafer, and the flat surrounding is used to fit the middle part of the reference edge of the wafer.

3. The sample holder for carrying a wafer according to claim 1, wherein, The length of the flat surrounding ranges from 80% to 90% of the length of the reference edge of the wafer.

4. The sample holder for carrying a wafer according to claim 3, wherein, The bottom of the groove further comprises an edge channel arranged at the edge of the wafer support surface, and the edge channel is arranged at the joint of the wafer support surface and the circular surrounding.

5. The sample holder for carrying a wafer according to claim 4, wherein, The bottom of the groove further comprises a stress release channel arranged at the central region of the wafer support surface, wherein the center of the stress release channel coincides with the center of the edge channel, and the radius of the stress release channel is 1 / 3 to 2 / 3 of the radius of the edge channel.

6. The sample holder for carrying wafers according to claim 4, wherein, The central angle of the edge channel ranges from 310 degrees to 328 degrees, the stress release channel is in the shape of a ring, the groove is used to carry a 4-inch wafer, the inner diameter of the edge channel ranges from 92 mm to 98 mm, the inner diameter of the stress release channel ranges from 46 mm to 56 mm, the difference between the inner diameter and the outer diameter of the edge channel ranges from 1 mm to 4 mm, and the difference between the inner diameter and the outer diameter of the stress release channel ranges from 1 mm to 4 mm.

7. The sample holder for carrying wafers according to claim 1, wherein, The height of the surrounding structure ranges from 0.5 mm to 5 mm, the height of the bottom surface of the edge channel below the wafer support surface ranges from 0.5 mm to 2 mm, and the height of the bottom surface of the stress release channel below the wafer support surface ranges from 0.5 mm to 2 mm.

8. The sample holder for carrying wafers according to claim 1, wherein, The convex corner region is a rounded corner region, the transition surrounding comprises a transition arc, the first end of the transition arc is tangent to the flat surrounding to form the convex corner region, the second end of the transition arc intersects with the circular surrounding to form the concave corner region, and the diameter of the transition arc ranges from 1 mm to 3 mm.

9. An epitaxial pedestal for carrying a wafer, the epitaxial pedestal comprising: The wafer support surface is directly connected to the flat surrounding.

10. The epitaxial pedestal for carrying a wafer of claim 1, wherein, The application further relates to a sample groove for carrying a wafer, which comprises the sample groove as claimed in any one of claims 1 to 8. The application further relates to a graphite base and a silicon carbide coating layer covering the surface of the graphite base.

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