Wafer tray, thin film deposition apparatus and method

Abstract

The present application provides wafer tray, thin film deposition equipment and method. The wafer tray includes a tray body and an edge ring. The edge of the upper surface of the tray body is provided with a plurality of first positioning parts. A plurality of first steps of different heights are provided in each of the first positioning parts. The edge of the lower surface of the edge ring is provided with a plurality of second positioning parts. A plurality of second steps of different heights are provided in each of the second positioning parts, for matching the first steps in the first positioning parts, mounting the edge ring to different heights of the upper surface of the tray body, and surrounding the wafer placed on the tray body, to adjust the plasma density of the wafer edge in the subsequent thin film deposition process. The present application can automatically adjust the distance between the edge ring and the wafer surrounded thereby by mounting the edge ring to different heights of the upper surface of the tray body, to adjust the plasma density of the wafer edge in the subsequent thin film deposition process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor device processing, and in particular to a wafer tray, a thin film deposition apparatus, and a thin film deposition method. BACKGROUND

[0002] In the field of semiconductor device processing, the uniformity and film thickness distribution of thin films directly affect the performance and production efficiency of semiconductor devices. During the thin film deposition process, the thickness of the thin film usually presents a distribution of thinner in the center region and thicker in the edge region, and this phenomenon of uneven film thickness is particularly evident at the edge of the wafer, which usually results in a larger fluctuation range of the edge film thickness, and even a significant difference in film thickness between high and low points. The prior art installs an edge ring on the wafer tray to change the film thickness of the wafer edge. However, the distance between the existing edge ring and the wafer tray is fixed, and if the distance is to be changed, the cavity needs to be opened by lowering the temperature and the edge accessory needs to be replaced, which obviously reduces the efficiency of the thin film deposition process.

[0003] In order to overcome the above-mentioned defects existing in the prior art, the present application provides an improved wafer tray for automatically adjusting the distance between the edge ring and the wafer surrounded thereby to adjust the plasma density of the wafer edge in the subsequent thin film deposition process. SUMMARY

[0004] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0005] In order to overcome the above-mentioned defects existing in the prior art, the present application provides a wafer tray, a thin film deposition apparatus, and a thin film deposition method, which can automatically adjust the distance between the edge ring and the wafer surrounded thereby by setting a positioning portion with multiple steps of different heights to install the edge ring at different heights on the upper surface of the tray body, so as to adjust the plasma density of the wafer edge in the subsequent thin film deposition process.

[0006] Specifically, the wafer tray according to the first aspect of the present application comprises a tray body and a rim ring. The edge of the upper surface of the tray body is provided with a plurality of first positioning portions. Each of the first positioning portions is provided with a plurality of first steps of different heights. The edge of the lower surface of the rim ring is provided with a plurality of second positioning portions. Each of the second positioning portions is provided with a plurality of second steps of different heights for matching the first steps in the first positioning portions, mounting the rim ring to different heights of the upper surface of the tray body, and surrounding the wafers placed on the tray body, so as to adjust the plasma density of the wafer edge in the subsequent thin film deposition process.

[0007] Further, in some embodiments of the present application, each of the first steps of each of the first positioning portions is respectively provided with a positioning hole or a positioning pin, and at least one of the second steps of each of the second positioning portions is respectively provided with a positioning pin or a positioning hole, so as to mount the rim ring to different heights of the upper surface of the tray body. Alternatively, at least one of the first steps of each of the first positioning portions is provided with a positioning pin or a positioning hole, and each of the second steps of each of the second positioning portions is respectively provided with a positioning hole or a positioning pin, so as to mount the rim ring to different heights of the upper surface of the tray body.

[0008] Further, in some embodiments of the present application, the edge of the upper surface of the tray body is provided with four first positioning portions. The edge of the lower surface of the rim ring is provided with four second positioning portions.

[0009] Further, in some embodiments of the present application, each of the first positioning portions is provided with six first steps. Each of the second positioning portions is provided with six second steps. The rim ring is rotated to a corresponding angle according to the film thickness distribution of the wafer edge, and is mounted on the corresponding six second steps via the six first steps, so as to mount the rim ring to different heights of the upper surface of the tray body.

[0010] Further, in some embodiments of the present application, the outer diameter of the rim ring is greater than the diameter of the tray body, so as to form a supporting portion. The wafer tray further comprises a ring-shaped supporting structure, a lifting mechanism, and a rotating mechanism. The ring-shaped supporting structure surrounds the tray body and the rim ring, so as to support the supporting portion of the rim ring. The lifting mechanism is used for lowering the tray body so that the first positioning portions are separated from the second positioning portions of the rim ring, and raising the tray body so that the first positioning portions contact and lock the second positioning portions of the rim ring. The rotating mechanism is used for rotating the tray body after the first positioning portions are separated from the second positioning portions, adjusting the alignment relationship between each of the first steps of the first positioning portions and each of the second steps of the second positioning portions, so as to adjust the mounting height of the rim ring.

[0011] Further, in some embodiments of the present application, the wafer tray further comprises a controller configured to: determine a deposition thickness distribution of the thin film deposition process on the wafer edge; determine a target distance between the edge ring and the tray body according to the deposition thickness distribution; lower the tray body via the lifting mechanism and rotate the tray body according to the target distance to align each of the second steps of the edge ring to a corresponding plurality of first steps; and raise the tray body via the lifting mechanism to mount the edge ring to a corresponding height of the upper surface of the tray body.

[0012] Further, in some embodiments of the present application, the step of determining the deposition thickness distribution of the thin film deposition process on the wafer edge comprises: obtaining an actual thin film thickness distribution and a target thin film thickness distribution of the wafer edge; and determining the deposition thickness distribution of the thin film deposition process on the wafer edge according to a difference between the actual thin film thickness distribution and the target thin film thickness distribution.

[0013] Further, in some embodiments of the present application, a heating element is integrated in the tray body for heating the wafer in the thin film deposition process.

[0014] In addition, the above-mentioned thin film deposition apparatus is provided according to the second aspect of the present application. The thin film deposition apparatus comprises a process chamber. The wafer tray as provided by the first aspect of the present application is configured in the process chamber.

[0015] In addition, the above-mentioned thin film deposition method is provided according to the third aspect of the present application, which comprises the following steps: determining a deposition thickness distribution of the thin film deposition process on the wafer edge; determining a target distance between an edge ring and a tray body of a wafer tray as provided by the first aspect of the present application according to the deposition thickness distribution; lowering the tray body via a lifting mechanism and rotating the tray body according to the target distance to align each of the second steps of the edge ring to a corresponding plurality of first steps; raising the tray body via the lifting mechanism to mount the edge ring to a corresponding height of an upper surface of the tray body; and performing a thin film deposition process on a wafer carried by the tray body and surrounded by the edge ring to achieve the target thin film thickness distribution on the edge of the wafer. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above features and advantages of the present application will be better understood through reading the detailed description of embodiments of the present application in conjunction with the following drawings, in which: the components are not necessarily drawn to scale, and components of similar or identical function or features are designated by the same or similar reference signs.

[0017] Figure 1 A schematic diagram of the structure of a wafer tray provided according to some embodiments of the present invention is shown.

[0018] Figure 2 A schematic cross-sectional view of a wafer tray provided according to some embodiments of the present invention is shown.

[0019] Figure 3 A schematic diagram of the structure of a wafer tray provided according to some embodiments of the present invention is shown.

[0020] Figure 4 A schematic diagram of the structure of an edge ring provided according to some embodiments of the present invention is shown.

[0021] Figure 5 A schematic diagram of the structure of a wafer tray provided according to some embodiments of the present invention is shown.

[0022] Figure 6 A schematic flowchart of a thin film deposition method according to some embodiments of the present invention is shown.

[0023] Figure 7 A diagram showing the electron density distribution inside a wafer tray according to some embodiments of the present invention is illustrated.

[0024] Figure 8 A diagram showing the electron density distribution inside a wafer tray according to some embodiments of the present invention is illustrated.

[0025] Figure label:

[0026] 11. Tray body

[0027] 111 First Positioning Department

[0028] 12 Edge rings

[0029] 121 Second Positioning Section

[0030] 122 Supporting Department

[0031] 13. Ring-shaped support structure Detailed Implementation

[0032] The advantages and features of the present application will become apparent to those skilled in the art who can gain an understanding of the application by reading the description of the embodiment with reference to the accompanying drawings. The description of the embodiment is presented for purposes of illustration and description and is not intended to limit the scope of the application as set forth in the appended claims. The description of the embodiment, given together with the attached drawings, aims to explain the principle of the application. The embodiment was selected on the basis of presenting the application in a clear and complete manner. The embodiment is not intended to limit the scope of the application as set forth in the appended claims. The description of the embodiment is presented for purposes of illustration and description and is not intended to limit the scope of the application as set forth in the appended claims. The description of the embodiment, given together with the attached drawings, aims to explain the principle of the application. The embodiment was selected on the basis of presenting the application in a clear and complete manner. The embodiment is not intended to limit the scope of the application as set forth in the appended claims. In the following description, numerous specific details are discussed, such as specific circuit configurations and processes, in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without these specific details. In other instances, well-known methods have not been described in detail in order to avoid obscuring the present application. In addition, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0033] In the description of the present application, it should be noted that unless specifically stated and limited otherwise, the terms "mounting", "connected", "connecting" should be interpreted broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, can be electrically connected; can be directly connected, can be indirectly connected through an intermediate medium, or can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] In addition, "upper", "lower", "left", "right", "top", "bottom", "horizontal", "vertical" used in the following description should be understood as the orientation shown in the section and the related drawings. The relative terms are only for the convenience of description, and they do not mean that the device described should be manufactured or operated in a particular orientation, so they should not be understood as limiting the application.

[0035] It can be understood that although the terms "first", "second", "third" and the like can be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below can be referred to as the second component, region, layer and / or part without departing from some embodiments of the present application.

[0036] As described above, during the thin film deposition process, the thickness of the thin film usually presents a distribution of thinner in the center region and thicker in the edge region, and this uneven film thickness phenomenon is particularly evident at the edge of the wafer, which usually causes a larger fluctuation range of the edge film thickness, and even a significant difference between the high and low points of the film thickness. The prior art installs an edge ring on the wafer tray to change the film thickness at the edge of the wafer. However, the distance between the existing edge ring and the wafer tray is fixed, and if the distance is to be changed, the cooling cavity needs to be opened and the edge accessory needs to be replaced, which obviously reduces the efficiency of the thin film deposition process.

[0037] To overcome the above-mentioned defects existing in the prior art, the present application provides a wafer tray, a thin film deposition apparatus and a thin film deposition method, which can automatically adjust the distance between the edge ring and the wafer surrounded thereby by setting the positioning portion with multiple steps of different heights to install the edge ring at different heights of the upper surface of the tray body, so as to adjust the plasma density of the wafer edge in the subsequent thin film deposition process.

[0038] In a non-limiting embodiment, the above-mentioned thin film deposition apparatus provided by the second aspect of the present application comprises a process chamber. Herein, the wafer tray provided by the first aspect of the present application is arranged in the process chamber.

[0039] For details, please further refer to the following description Figures 1-4 . Figure 1 A structural schematic diagram of a wafer tray provided by some embodiments of the present application is shown. Figure 2 A cross-sectional schematic diagram of a wafer tray provided by some embodiments of the present application is shown. Figure 3 A structural schematic diagram of a wafer tray provided by some embodiments of the present application is shown. Figure 4 A structural schematic diagram of an edge ring provided by some embodiments of the present application is shown.

[0040] In Figures 1-4 The above-mentioned wafer tray provided by the first aspect of the present application comprises a tray body 11 and an edge ring 12. The edge of the upper surface of the tray body 11 is provided with multiple first positioning portions 111. Herein, multiple first steps of different heights are arranged in each first positioning portion 111. The edge of the lower surface of the edge ring 12 is provided with multiple second positioning portions 121. Herein, multiple second steps of different heights are arranged in each second positioning portion 121, which are used to cooperate with the first steps in the first positioning portions 111 to install the edge ring 12 at different heights of the upper surface of the tray body 11 and surround the wafer placed on the tray body 11, so as to adjust the plasma density of the wafer edge in the subsequent thin film deposition process.

[0041] Further, in Figure 3 and Figure 4 The above-mentioned wafer tray provided by the first aspect of the present application comprises a tray body 11 and an edge ring 12. The edge of the upper surface of the tray body 11 is provided with multiple first positioning portions 111. Herein, multiple first steps of different heights are arranged in each first positioning portion 111. The edge of the lower surface of the edge ring 12 is provided with multiple second positioning portions 121. Herein, multiple second steps of different heights are arranged in each second positioning portion 121, which are used to cooperate with the first steps in the first positioning portions 111 to install the edge ring 12 at different heights of the upper surface of the tray body 11 and surround the wafer placed on the tray body 11, so as to adjust the plasma density of the wafer edge in the subsequent thin film deposition process.

[0042] Alternatively, in some embodiments, each first positioning portion 111 is provided with a positioning hole or a positioning pin on each first step, and at least one second positioning portion 121 is provided with a positioning pin or a positioning hole on each second step, so as to mount the edge ring 12 to different heights of the upper surface of the tray body 11.

[0043] In Figures 1-3 the illustrated embodiment, the edge of the upper surface of the tray body 11 is provided with four first positioning portions 111. In Figures 1-4 the illustrated embodiment, the edge of the lower surface of the edge ring 12 is provided with four second positioning portions 121.

[0044] Further, in Figures 1-3 the illustrated embodiment, each first positioning portion 111 is provided with six first steps, each second positioning portion 121 is provided with six second steps, the edge ring 12 is rotated to a corresponding angle according to the film thickness distribution of the wafer edge, and is mounted on the corresponding six second steps via the six first steps, so as to mount the edge ring 12 to different heights of the upper surface of the tray body 11.

[0045] Please refer to Figure 5 . Figure 5 A structural schematic diagram of a wafer tray provided according to some embodiments of the present application is shown.

[0046] In Figure 5 the illustrated embodiment, the outer diameter of the edge ring 12 is greater than the diameter of the tray body 11, so as to form a supporting portion 122. In this regard, the above-mentioned wafer tray provided by the first aspect of the present application further comprises a ring-shaped support structure 13, a lifting mechanism and a rotating mechanism. The ring-shaped support structure 13 surrounds the tray body 11 and the edge ring 12, so as to support the supporting portion 122 of the edge ring 12. The lifting mechanism is used to lower the tray body 11, so that the first positioning portions 111 thereof are disengaged from the second positioning portions 121 of the edge ring 12, and is used to raise the tray body 11, so that the first positioning portions 111 thereof contact and lock the second positioning portions 121 of the edge ring 12. The rotating mechanism is used to rotate the tray body 11 after the first positioning portions 111 are disengaged from the second positioning portions 121, so as to adjust the alignment relationship between each first step of the first positioning portions 111 and each second step of the second positioning portions 121, so as to adjust the mounting height of the edge ring 12.

[0047] In addition, in some optional embodiments, the above-mentioned wafer tray provided by the first aspect of the present application further comprises a controller. In this regard, the controller can be connected to the above-mentioned lifting mechanism and rotating mechanism, so as to implement the film deposition method provided by the third aspect of the present application.

[0048] In addition, in some optional embodiments, the above-mentioned tray body 11 is integrated with a heating element, which is used to heat the wafer in the film deposition process.

[0049] The working principle of the thin film deposition apparatus will be described in combination with some embodiments of thin film deposition methods. Those skilled in the art can understand that the embodiments of the thin film deposition methods are only some non-limiting embodiments provided by the present application, which are intended to clearly show the main concept of the present application and provide some specific solutions for facilitating the public to implement, but not to limit the overall function or overall working mode of the thin film deposition apparatus. Similarly, the thin film deposition apparatus is also only a non-limiting embodiment provided by the present application, which does not limit the execution subject or execution order of each step in the thin film deposition methods.

[0050] Please refer to Figure 6 . Figure 6 A flowchart of a thin film deposition method according to some embodiments of the present application is shown.

[0051] As Figure 6 shown, the thin film deposition apparatus provided by the second aspect of the present application can first determine the deposition thickness distribution of the wafer edge by the thin film deposition process.

[0052] Specifically, the thin film deposition apparatus can first obtain the actual thin film thickness distribution and the target thin film thickness distribution of the wafer edge, and determine the deposition thickness distribution of the wafer edge by the thin film deposition process according to the difference between the actual thin film thickness distribution and the target thin film thickness distribution.

[0053] In addition, in the process of the thin film deposition process, there are product correction process scenarios in which the actual thin film thickness distribution is uneven but the target thin film thickness distribution is uniform, customized process scenarios in which the actual thin film thickness distribution is uniform but the target thin film thickness distribution is uneven, and error compensation process scenarios in which the actual thin film thickness distribution and the target thin film thickness distribution are both uniform but the thin film deposition rate is uneven.

[0054] Then, the thin film deposition apparatus can determine the target distance between the edge ring and the tray body of the wafer tray according to the deposition thickness distribution, as provided by the first aspect of the present application.

[0055] Then, the thin film deposition apparatus can lower the tray body via the lifting mechanism, and rotate the tray body according to the target distance, so as to align each second step of the edge ring with the corresponding plurality of first steps.

[0056] Then, the thin film deposition apparatus can raise the tray body via the lifting mechanism, so as to install the edge ring at the corresponding height on the upper surface of the tray body.

[0057] Then, the thin film deposition apparatus can perform the thin film deposition process on the wafer carried by the tray body and surrounded by the edge ring, so as to make the edge of the wafer reach the target thin film thickness distribution.

[0058] Please refer toFigure 7 and Figure 8 . Figure 7 A wafer tray internal electron density distribution map is shown according to some embodiments of the present application. Figure 8 A wafer tray internal electron density distribution map is shown according to some embodiments of the present application.

[0059] As Figure 7 and Figure 8 shown, the wafer tray provided by the first aspect of the present application can reduce the area range of the higher electron density by reducing the longitudinal distance between the edge ring and the wafer, so as to reduce the deposition rate at the edge, thereby avoiding the problem of over-thick film deposition at the wafer edge. In this way, the wafer tray provided by the first aspect of the present application can adjust the distance between the edge ring 12 and the wafer surrounded thereby according to the film thickness distribution on the wafer surface during the film deposition process, so as to adjust the film thickness at the wafer edge, thereby improving the uniformity of the film deposited on the wafer surface.

[0060] In summary, the wafer tray, the film deposition apparatus and the film deposition method provided by the present application can automatically adjust the distance between the edge ring and the wafer surrounded thereby by installing the edge ring to the upper surface of the tray body at different heights of the positioning portion having multiple steps of different heights, so as to adjust the plasma density at the wafer edge in the subsequent film deposition process.

[0061] Although the methods are illustrated and described above as a series of acts, it will be appreciated that the methods are not limited by the order of acts as some acts can, in accordance with one or more embodiments, occur simultaneously or in different orders with respect to other acts described herein or with respect to other acts not described herein but will be apparent to those skilled in the art.

[0062] Those skilled in the art will understand that information, signals, and data can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0063] Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

[0064] The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0065] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the processor and the storage medium can reside as discrete components in a user terminal.

[0066] In one or more exemplary embodiments, the functions described can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0067] The previous description of the disclosure is provided to enable any persons skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the example and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wafer tray, characterized by, The tray body has a plurality of first positioning portions on the edge of the upper surface, wherein each of the first positioning portions has a plurality of first steps with different heights; and The edge ring has a plurality of second positioning portions on the edge of the lower surface, wherein each of the second positioning portions has a plurality of second steps with different heights, and the second steps are matched with the first steps in the first positioning portions to install the edge ring to the upper surface of the tray body at different heights and to surround the wafer on the tray body to adjust the plasma density of the wafer edge in the subsequent thin film deposition process. Each of the first steps in each of the first positioning portions is respectively provided with a positioning hole or a positioning pin, and at least one of the second steps in each of the second positioning portions is respectively provided with a positioning pin or a positioning hole to install the edge ring to the upper surface of the tray body at different heights, or 2. The wafer tray of claim 1, wherein, At least one of the first steps in each of the first positioning portions is provided with a positioning pin or a positioning hole, and each of the second steps in each of the second positioning portions is respectively provided with a positioning hole or a positioning pin to install the edge ring to the upper surface of the tray body at different heights. The upper surface of the tray body has four first positioning portions on the edge, and the lower surface of the edge ring has four second positioning portions on the edge.

3. The wafer tray of claim 1, wherein, Each of the first positioning portions has six first steps, and each of the second positioning portions has six second steps, and the edge ring is rotated to a corresponding angle according to the thin film thickness distribution of the wafer edge and is installed on the corresponding six second steps via the six first steps to install the edge ring to the upper surface of the tray body at different heights.

4. The wafer tray of claim 3, wherein, The outer diameter of the edge ring is greater than the diameter of the tray body to form a supporting portion, and the wafer tray further comprises:

5. The wafer tray of claim 1, wherein, A ring-shaped supporting structure surrounding the tray body and the edge ring to support the supporting portion of the edge ring; A lifting mechanism for lowering the tray body to make the first positioning portions of the tray body disengage from the second positioning portions of the edge ring, and for raising the tray body to make the first positioning portions of the tray body contact and lock the second positioning portions of the edge ring; and A rotating mechanism for rotating the tray body to adjust the alignment relationship between each of the first steps of the first positioning portions and each of the second steps of the second positioning portions after the first positioning portions disengage from the second positioning portions to adjust the installation height of the edge ring. The wafer tray further comprises a controller configured to:

6. The wafer tray of claim 5, wherein, Determine the deposition thickness distribution of the wafer edge in the thin film deposition process; Determine the target distance between the edge ring and the tray body according to the deposition thickness distribution; Lower the tray body via the lifting mechanism and rotate the tray body according to the target distance to align each of the second steps of the edge ring with a corresponding plurality of first steps; and Raise the tray body via the lifting mechanism to install the edge ring to the upper surface of the tray body at a corresponding height. The step of determining the deposition thickness distribution of the wafer edge in the thin film deposition process comprises:

7. The wafer tray of claim 6, wherein, ​ acquire an actual film thickness distribution and a target film thickness distribution of the wafer edge; and determine a deposition thickness distribution of the film deposition process on the wafer edge according to a difference between the actual film thickness distribution and the target film thickness distribution.

8. The wafer tray of claim 1, wherein, The tray body is integrated with a heating element for heating the wafer in the film deposition process.

9. A thin film deposition apparatus, characterized by, The film deposition device comprises a process chamber, and the process chamber is configured with the wafer tray as claimed in any one of claims 1-8.

10. A method of thin film deposition, characterized by, comprising the following steps: determine a deposition thickness distribution of a film deposition process on a wafer edge; determine a target distance between an edge ring and a tray body of the wafer tray as claimed in any one of claims 1-8 according to the deposition thickness distribution; lower the tray body via a lifting mechanism and rotate the tray body according to the target distance to align each second step of the edge ring to a corresponding plurality of first steps; raise the tray body via the lifting mechanism to mount the edge ring to a corresponding height on the upper surface of the tray body; and perform a film deposition process on a wafer carried by the tray body and surrounded by the edge ring to achieve a target film thickness distribution on the edge of the wafer.

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