Wafer supporting structure and chemical vapor deposition device

Abstract

The utility model discloses a wafer supporting structure and a chemical vapor deposition device, the wafer supporting structure comprises a tray used for bearing a wafer and an annular lining used for supporting the edge of the tray, the diameter of the bottom surface of the edge of the tray is smaller than that of the maximum edge of the tray, and the annular lining is used for supporting the edge of the tray. Compared with the prior art, the part, exceeding the outer diameter of the lining, of the edge of the tray is greatly reduced, the area, which cannot be directly heated by a heating device, of the tray is reduced, and therefore the temperature difference between the edge of the tray and the center of the tray is reduced compared with the prior art, and the temperature difference between the edge of the tray and the center of the tray is reduced. Not only is the service life of the tray prolonged, but also the temperature uniformity of the tray is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor processing, in particular to a wafer support structure and a chemical vapor deposition device. Background Art

[0002] Vapor deposition technology is a technology for depositing thin films on substrates, such as semiconductor wafers. Among them, MOCVD (metal-organic chemical vapor deposition) is a technology that uses organic compounds of group III elements and ammonia or oxygen as crystal growth source materials, and performs vapor phase epitaxy on wafers in a thermal decomposition reaction to grow various compound semiconductor films.

[0003] Typically, the wafer to be processed is placed on the wafer support structure of the reaction chamber of the MOCVD device. The heat energy provided by the heating device in the reaction chamber is transferred to the wafer to be processed through the tray of the wafer support structure. At the same time, reaction gas is introduced into the reaction chamber to epitaxially grow a semiconductor thin film on the surface of the wafer to be processed.

[0004] The wafer support structure includes a bushing and a tray arranged above the bushing. When a semiconductor film is grown on the surface of the wafer to be processed, the heat energy of the heating device is first transferred to the tray, and then transferred from the tray to the wafer to be processed. The current tray diameter is larger than the bushing to facilitate the robot arm to pick up and place the tray. However, since the heating device is located in the bushing, the part of the tray outside the bushing cannot be directly heated by the heating device. Instead, the heat energy is transferred to the tray area outside the bushing through heat transfer, which leads to a large temperature difference between the center and edge of the tray, reduced temperature uniformity of the tray, and large internal thermal stress, which reduces the service life of the tray. In addition, the temperature uniformity of the tray will also affect the temperature uniformity of the wafer to be processed, thereby affecting the process effect of the wafer. Utility Model Content

[0005] In view of the deficiencies of the prior art, the utility model provides a wafer support structure and a chemical vapor deposition device to improve the temperature uniformity of a tray.

[0006] To achieve the above-mentioned purpose, the utility model proposes a wafer support structure, comprising: a tray for carrying wafers, and an annular sleeve supporting the edge of the tray; wherein the bottom diameter of the tray edge is smaller than the diameter at the maximum edge of the tray, and the difference between the diameter at the maximum edge of the tray and the outer diameter of the sleeve does not exceed 1% to 5% of the outer diameter of the sleeve.

[0007] Optionally, the bottom diameter of the tray edge is greater than or equal to the inner diameter of the bushing.

[0008] Optionally, the bottom diameter of the tray edge is less than or equal to the outer diameter of the bushing.

[0009] Optionally, the diameter of the tray decreases monotonically from the maximum edge to the bottom diameter of the tray edge.

[0010] Optionally, a vertical distance between the maximum edge of the tray and the bottom surface of the tray is 0.2h to 0.8h, wherein h is a vertical distance between the bottom edge and the top edge of the tray.

[0011] Optionally, the connecting surface between the maximum edge of the tray and the edge of the bottom surface of the tray is a slope.

[0012] Optionally, the angle between the inclined surface and the bottom surface of the tray is 100° to 170°.

[0013] Optionally, the connecting surface between the maximum edge of the tray and the edge of the bottom surface of the tray is an arc transition surface.

[0014] Optionally, the angle between the curved surface and the bottom surface of the tray is 100° to 170°.

[0015] Optionally, the difference between the diameter at the maximum edge of the tray and the outer diameter of the bushing does not exceed half of the vertical distance between the bottom edge and the top edge of the tray.

[0016] Optionally, the maximum edge of the tray is connected to the top edge of the tray edge by an arc transition chamfer.

[0017] Optionally, a central portion of the tray has a boss or an annular protrusion extending downward, and the boss or annular protrusion is located in the bushing to limit the radial position of the tray.

[0018] On the other hand, the utility model also provides a chemical vapor deposition device, comprising: a reaction chamber; a wafer support structure as mentioned above, located in the reaction chamber and used to carry the wafer; a heating device, arranged in the sleeve and used to heat the tray; a gas shower head, located in the reaction chamber and arranged opposite to the tray, and used to transport reaction gas into the reaction chamber.

[0019] Compared with the prior art, the utility model has at least the following advantages and beneficial effects:

[0020] The wafer support structure proposed by the utility model includes a tray and a bushing supporting the edge of the tray. The difference between the diameter at the maximum edge of the tray and the outer diameter of the bushing does not exceed 1% to 5% of the outer diameter of the bushing. Compared with the prior art, the portion of the tray edge that exceeds the outer diameter of the bushing is greatly reduced, and the area of ​​the edge portion that cannot be directly heated by the heating device is reduced, so that the temperature difference between the edge and the center of the tray is reduced compared with the prior art, which not only extends the life of the tray, but also improves the temperature uniformity of the tray, thereby reducing the influence of the poor temperature uniformity of the tray on the wafer process effect.

[0021] In the utility model, the bottom edge of the edge of the tray is on the inner side of the outer wall of the bushing and on the outer side of the inner wall of the bushing, and the position of the edge of the tray is limited above the side wall of the bushing. While ensuring the stability of the tray above the bushing, the area where the tray protrudes beyond the bushing is further reduced, and the temperature difference between the edge and the center of the tray is reduced.

[0022] In the utility model, the maximum edge of the tray is located in the middle of the thickness of the tray and is not close to the bottom surface or the top surface of the tray, thereby avoiding the concentration of thermal stress at the maximum edge.

[0023] In the utility model, the connecting surface between the maximum edge of the tray and the edge of the bottom surface of the tray is a bevel or an arc transition curved surface, and there is no additional protrusion on the connecting surface, so that the heat energy can be smoothly transitioned on the connecting surface, thereby avoiding the concentration of thermal stress; further, the maximum edge of the tray and the edge of the top surface of the tray are connected by an arc transition chamfer, so the angle formed at the maximum edge is larger, and it is not easy to form a sharp point, thereby avoiding the concentration of thermal stress at the maximum edge of the tray. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a current wafer support structure;

[0025] Figure 2 A schematic diagram of a wafer support structure provided by an embodiment of the utility model;

[0026] Figure 3 for Figure 2 A schematic diagram of the structure of the connection surface in FIG.

[0027] Figure 4 A schematic diagram of a wafer support structure provided by another embodiment of the utility model;

[0028] Figure 5 for Figure 4 A schematic diagram of the structure of the connection surface in FIG.

[0029] Figure 6 This is a schematic diagram of a chemical vapor deposition device provided by the utility model. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to describe in detail the technical solution, structural features, objectives and effects of a wafer support structure and a chemical vapor deposition device proposed by the present invention. The description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the implementation methods of the utility model, and are not used to limit the conditions for the implementation of the utility model. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the utility model without affecting the efficacy and purpose that can be achieved by the utility model.

[0032] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0033] like Figure 1 The figure shows a wafer support structure at present, including a sleeve 300' and a tray 200' arranged above the sleeve 300', wherein the tray 200' is used to carry the wafer 100, and the sleeve 300' is annular, and a heating device 400 is arranged inside the sleeve to heat the tray 200' and thus heat the wafer 100. As described in the background technology, the edge of the tray 200' greatly exceeds the outer wall of the sleeve 300' below it (hereinafter, the portion of the edge of the tray 200' exceeding the outer wall of the sleeve 300' is recorded as the edge portion 201'). Although this is convenient for the robot arm to take and place the tray 200 ', but there is no heating device 400 under the edge portion 201' and it is inconvenient to set it, so the edge portion 201' cannot be directly heated by the heating device 400, and can only be heated by heat transfer from the center to the edge of the tray 200', which leads to a large temperature difference between the edge and the center of the tray 200', resulting in poor temperature uniformity of the tray 200' and large thermal stress in the tray 200', which will not only affect the service life of the tray 200', but also affect the temperature uniformity of the wafer 100 above the tray 200', thereby affecting the process treatment effect on the surface of the wafer 100.

[0034] In order to solve the above problems, the utility model proposes a wafer support structure, which can reduce the temperature difference between the edge and the center of the tray and improve the temperature uniformity of the tray.

[0035] like Figure 2The wafer support structure of an embodiment of the utility model is shown, and the wafer support structure includes a tray 200 and a bushing 300 disposed under the tray 200. The bushing 300 is annular and supported at the edge of the tray 200, and can drive the tray 200 to rotate. The tray 200 is disc-shaped, and has a groove at the center of its top surface for carrying the wafer 100. The tray 200 has a downwardly extending boss 600 in the middle, and the boss 600 is located in the bushing 300, and is used to limit the radial position of the tray 200.

[0036] In other embodiments, the boss 600 may also be a hollow structure in the middle, that is, an annular protrusion, which is located in the bushing 300 and is used to limit the radial position of the tray 200.

[0037] The bottom edge of the tray 200 is connected to the top edge via a connecting surface 500. Figure 3 As shown, the connecting surface 500 is a ring surface with a protrusion, and the highest point of the protrusion is the maximum edge 502 of the tray 200; the maximum edge 502 is located outside the outer wall of the liner 300, and the difference between the diameter of the maximum edge 502 and the outer diameter of the liner 300 is d, and d is not greater than 1% to 5% of the outer diameter of the liner 300; the portion of the edge of the tray 200 that exceeds the outer wall of the liner 300 is the edge portion 201, and the edge portion 201 is annular, and its width is the difference d between the diameter of the maximum edge 502 of the tray 200 and the outer diameter of the liner 300. Compared with the prior art, the structure of this embodiment removes most of the area of ​​the tray 200 protruding from the outer wall of the liner 300, and reduces the area of ​​the edge portion 201 that cannot be directly heated by the heating device 400, so that under the same heating device 400, the temperature difference between the edge and the center of the tray 200 is reduced compared with the prior art, and the temperature uniformity of the tray 200 is optimized.

[0038] Furthermore, the difference d between the diameter 502 of the maximum edge of the tray 200 and the outer diameter of the bushing 300 is no greater than half the thickness of the edge portion 201, thereby further reducing the area of ​​the tray 200 protruding from the outer wall of the bushing 300 and further reducing the temperature difference between the edge and the center of the tray 200.

[0039] The bottom diameter of the edge of the tray 200 is smaller than the diameter of the maximum edge 502 of the tray, and because the maximum edge 502 protrudes from the outer wall of the bushing 300 , the robot arm can pick up and place the tray 200 through the maximum edge 502 .

[0040] The vertical distance between the maximum edge 502 of the tray 200 and the bottom surface of the tray 200 is 0.2h-0.8h, where h is the vertical distance between the bottom edge and the top edge of the tray 200, and is also the thickness of the edge portion 201. It can be understood that the maximum edge 502 has a smaller thickness in the vertical direction than the edge portion 201, that is, the maximum edge 502 is an annular flange with a head that is smaller than the bottom and protrudes laterally relative to the edge portion 201. In the vertical direction, by arranging the maximum edge 502 of the tray 200 near the middle of the tray 200 rather than near the top or bottom surface of the tray 200, it is avoided that there is no transition slope or arc surface between the maximum edge 502 and the edge portion 201, forming a sharp annular edge, and avoiding the formation of sharp thermal stress concentration at the maximum edge 502.

[0041] The bottom surface of the tray 200 (except the boss 600) is a plane, and the bottom diameter of the edge of the tray 200 is greater than or equal to the inner diameter of the bushing 300, that is, the bottom edge of the tray 200 is located on or outside the inner wall of the bushing 300, and the connecting surface 500 is located outside the inner wall of the bushing 300, so that the tray 200 can be stably set above the bushing 300 and rotate therewith.

[0042] Furthermore, the bottom diameter of the edge of the tray 200 is also smaller than or equal to the outer diameter of the bushing 300, that is, the bottom edge of the tray 200 is located on the outer wall or inner side of the bushing 300, so that the connection point between the connection surface 500 and the bottom surface of the tray is located on the side wall of the bushing 300. On the basis of maintaining the stability of the tray 200, the area of ​​the edge portion 201 that cannot be directly heated by the heating device 400 is further reduced, and the temperature difference between the edge and the center of the tray 200 is further reduced, thereby optimizing the temperature uniformity of the tray 200. Figure 3 The figure shows that the bottom diameter of the edge of the tray 200 is equal to the outer diameter of the bushing 300 , and the bottom edge of the tray 200 is located on the outer side wall of the bushing 300 .

[0043] like Figure 3 As shown, the connecting surface 500 also includes a first connecting surface 501 connecting the maximum edge 502 of the tray 200 and the top edge of the tray 200 and a second connecting surface 503 connecting the maximum edge 502 of the tray 200 and the bottom edge of the tray 200; the diameter from the maximum edge 502 of the tray 200 to the bottom diameter of the edge of the tray 200 and the diameter from the maximum edge 502 of the tray 200 to the top diameter of the edge of the tray 200 both decrease monotonically. In this embodiment, the second connecting surface 503 is a slope, and the first connecting surface 501 is an arc transition surface, that is, the second connecting surface 503 and the top edge of the edge of the tray 200 are connected by an arc transition chamfer to avoid the formation of tip stress concentration.

[0044] In other embodiments, the first connecting surface 501 may also be a bevel, but compared with the angle and tip formed by the connection between the bevels, the angle formed by the connection between the arc transition surface and the bevel is larger, and the transition between the two connecting surfaces is also smoother. At this connection, that is, the maximum edge 502, it is less likely to produce thermal stress concentration.

[0045] The angle between the second connection surface 503 and the bottom surface of the tray 200 is an obtuse angle, which is 100° to 170° in this embodiment, so as to provide a forking space for the robot arm, so that the robot arm can reach in from the second connection surface 503 to clamp the maximum edge 502 to pick up and place the tray 200. The setting of the obtuse angle, on the one hand, provides space for the forking of the robot arm, so that the diameter of the maximum edge 502 can be further reduced, thereby reducing the distance extending out of the bushing 300, so that the temperature of the tray 200 is more uniform; on the other hand, it avoids the formation of tip stress concentration at the maximum edge 502.

[0046] like Figure 4 and Figure 5 The wafer support structure of another embodiment is shown. The connection surface 500 of this embodiment also includes a first connection surface 501, a second connection surface 503 and a maximum edge 502. The first connection surface 501 is a circular arc transition surface, and the maximum edge 502 is located at the connection between the first connection surface 501 and the second connection surface 503. However, different from the above embodiment, the second connection surface 503 of this embodiment is a circular arc transition surface, that is, the circular arc transition surface is used to replace the inclined surface in the above embodiment to connect the maximum edge 502 of the tray 200 and the bottom edge of the tray 200. At this time, the first connection surface 501 and the second connection surface 503 are both circular arc surfaces, and the angle formed by the connection between the two is larger. It is less likely to form a sharp tip at the maximum edge 502, thereby reducing the concentration of thermal stress at the maximum edge 502.

[0047] Similar to the above-mentioned embodiment, the angle between the second connecting surface 503 which is an arc transition curved surface and the bottom surface of the tray 200 is also 100° to 170°.

[0048] The curvatures of the first connecting surface 501 and the second connecting surface 503 may be the same or different. When the curvatures of the two are the same, the connecting surface 500 is a complete arc, and the maximum edge 502 is its vertex. On its symmetry axis, that is, Figure 4 and Figure 5 The situation shown.

[0049] In other embodiments, when the second connecting surface 503 is an arc transition surface, the first connecting surface 501 can also be an inclined surface, but at this time the angle at the maximum edge 502 is smaller than when two arc transition surfaces are connected, and the thermal stress at the maximum edge 502 is also more concentrated.

[0050] In more embodiments, the first connecting surface 501 and the second connecting surface 503 can also be connected arc transition chamfers and bevels. The first connecting surface 501 and the second connecting surface 503 are connected by their respective arc transition chamfers. At this time, the maximum edge 502 is located at the connection between the two arc transition chamfers or on any arc transition chamfer.

[0051] like Figure 6 As shown, the utility model also provides a chemical vapor deposition device, including a reaction chamber 700, and any of the above-mentioned wafer support structures arranged in the reaction chamber 700, the wafer support structure is used to carry the wafer 100, the wafer support structure includes a tray 200 and an annular sleeve 300 supporting the edge of the tray 200; it also includes a heating device 400, which is arranged in the sleeve 300 and is used to heat the tray 200, and then heat the wafer 100 on the tray 200.

[0052] The bottom diameter of the edge of the tray 200 is smaller than the diameter at the maximum edge of the tray 200, and the difference between the diameter at the maximum edge of the tray 200 and the outer diameter of the bushing 300 does not exceed 1% to 5% of the outer diameter of the bushing. This structure removes most of the area of ​​the tray 200 protruding from the outer wall of the bushing 300, reduces the area of ​​the edge portion 201 that cannot be directly heated by the heating device 400, reduces the temperature difference between the edge and the center of the tray 200, and optimizes the temperature uniformity of the tray 200.

[0053] A gas shower head 800 is further disposed in the reaction chamber 700 , and is disposed opposite to the tray 200 , and is used to transport reaction gas into the reaction chamber 700 .

[0054] In this embodiment, the chemical vapor deposition device is a metal organic compound chemical vapor deposition device.

[0055] In other embodiments, other types of chemical vapor deposition devices may be used.

[0056] The above is only a preferred embodiment of the utility model. Although the utility model has been disclosed as a preferred embodiment, it is not intended to limit the utility model. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the utility model by using the above disclosed methods and technical contents without departing from the scope of the technical solution of the utility model, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.

Claims

1. A wafer support structure, characterized in that: include: A tray for carrying wafers, and an annular bushing for supporting the edge of the tray; The bottom diameter of the tray edge is smaller than the diameter at the maximum edge of the tray, and the difference between the diameter at the maximum edge of the tray and the outer diameter of the bushing does not exceed 1% to 5% of the outer diameter of the bushing.

2. The wafer support structure according to claim 1, characterized in that: The bottom diameter of the tray edge is greater than or equal to the inner diameter of the bushing.

3. The wafer support structure according to claim 1, characterized in that: The bottom diameter of the tray edge is smaller than or equal to the outer diameter of the bushing.

4. The wafer support structure according to claim 1, characterized in that: The diameter at the maximum edge of the tray decreases monotonically to the bottom diameter of the tray edge.

5. The wafer support structure according to claim 1, characterized in that: The vertical distance between the maximum edge of the tray and the bottom surface of the tray is 0.2h-0.8h, wherein h is the vertical distance between the bottom edge and the top edge of the tray.

6. The wafer support structure according to claim 5, characterized in that: The connecting surface between the maximum edge of the tray and the edge of the bottom surface of the tray is an inclined surface.

7. The wafer support structure according to claim 6, characterized in that: The included angle between the inclined surface and the bottom surface of the tray is 100° to 170°.

8. The wafer support structure according to claim 5, characterized in that: The connecting surface between the maximum edge of the tray and the edge of the bottom surface of the tray is an arc transition curved surface.

9. The wafer support structure according to claim 8, characterized in that: The angle between the curved surface and the bottom surface of the tray is 100° to 170°.

10. The wafer support structure according to claim 1, characterized in that: The difference between the diameter at the maximum edge of the tray and the outer diameter of the bushing does not exceed half of the vertical distance between the bottom edge and the top edge of the tray.

11. The wafer support structure according to claim 6 or 8, characterized in that: The maximum edge of the tray is connected to the top edge of the tray edge by a circular arc transition chamfer.

12. The wafer support structure according to any one of claims 1 to 10, characterized in that: The tray has a downwardly extending boss or annular protrusion in the middle, and the boss or annular protrusion is located in the bushing to limit the radial position of the tray.

13. A chemical vapor deposition device, characterized in that: include: Reaction chamber; The wafer support structure according to any one of claims 1 to 12, located in the reaction chamber and used to support the wafer; A heating device, disposed in the sleeve, for heating the tray; The gas shower head is located in the reaction chamber, arranged opposite to the tray, and is used for conveying reaction gas into the reaction chamber.

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