Heating disc structure for improving film uniformity and semiconductor equipment

Abstract

The invention discloses a heating disc structure for improving film uniformity and semiconductor equipment. The heating disc structure comprises a tray body located in a reaction cavity and used for bearing a substrate for thin film deposition; the grounding electrode is arranged inside the tray body and used for leading out radio frequency energy, the grounding electrode comprises a first area with a first embedding depth and a second area with a second embedding depth, and the second embedding depth is larger than the first embedding depth. Through the heating disc structure, the overall uniformity of thin film deposition can be obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to a heating plate structure and a semiconductor device. Background Art

[0002] As the manufacturing process of semiconductor devices continues to improve, the uniformity requirements of thin films continue to increase. The heating plate, as the lower plate in the plasma enhanced chemical vapor deposition (PECVD) equipment, has a crucial impact on the process performance of the thin film.

[0003] However, in the prior art, the structure and arrangement of the ground electrode in the heating plate are limited, and it is impossible to ensure that the reaction conditions are consistent across the entire substrate surface, thereby obtaining a uniform film. Currently, the heating plate in the PECVD equipment cannot reduce the uniformity of the film deposited on the substrate surface to less than 1.2%.

[0004] In order to solve the above problems existing in the prior art, there is an urgent need in the art for an improved heating plate structure that can significantly improve the overall uniformity of thin film deposition. Summary of the invention

[0005] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or decisive elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0006] In order to overcome the above-mentioned defects in the prior art, the present invention provides a heating plate structure and a semiconductor device, which can significantly improve the overall uniformity of thin film deposition.

[0007] Specifically, the above-mentioned heating plate structure provided according to the first aspect of the present invention includes: a tray body, located in the reaction chamber, for supporting the substrate for thin film deposition; and a grounding electrode, arranged inside the tray body, for extracting radio frequency energy, wherein the grounding electrode includes a first area with a first burial depth and a second area with a second burial depth, and the second burial depth is greater than the first burial depth.

[0008] Furthermore, in some embodiments of the present invention, the first area is located in the central area of ​​the ground electrode and is aligned with the air inlet above the heating plate structure, and the second area is located in the edge area of ​​the ground electrode and is away from the air inlet.

[0009] Furthermore, in some embodiments of the present invention, the depth difference obtained by subtracting the first burying depth from the second burying depth is smaller than the first preset depth difference and larger than the second preset depth difference.

[0010] Further, in some embodiments of the present invention, the first preset depth difference is 0.3 mm, and the second preset depth difference is 0.1 mm.

[0011] Further, in some embodiments of the present invention, the ground electrode includes any one of a first shape with a concave center, a second shape with a convex center, and a third shape with continuous undulations.

[0012] Further, in some embodiments of the present invention, the ground electrode is in the first shape or the second shape, and the angle between the edge of the ground electrode and the upper surface of the tray body is in the range of 30° to 160°.

[0013] Furthermore, in some embodiments of the present invention, the diameter of the ground electrode is larger than the diameter of the substrate and smaller than the diameter of the tray body, wherein the distance between the depth variation region in the ground electrode and the edge of the ground electrode is 3 to 15 mm.

[0014] Furthermore, in some embodiments of the present invention, the heating plate structure is applied to a high frequency electric field in the frequency range of 2 MHz to 100 MHz, so that the total impedance in the tray body and the buried depth of the ground electrode conform to the following rule:

[0015]

[0016] Among them, Z total represents the total impedance of the heating plate structure, Z C represents the capacitive reactance and Z L represents the loop inductive reactance and Z L =ωL, ω represents the angular frequency of the alternating current, C is the capacitance, d represents the buried depth of the grounding electrode, ε represents the dielectric constant of the medium between the grounding electrode and the upper surface of the tray body, S represents the area of ​​the grounding electrode, L is the inductance, and Z L Greater than Z C , Z total is positive, the greater the buried depth d of the corresponding grounding electrode, the greater the total impedance Z total The smaller it is, the greater the current in the tray body.

[0017] In addition, the semiconductor device provided according to the second aspect of the present invention comprises: a reaction chamber, the upper part of which comprises an air inlet for introducing process gas; and the heating plate structure provided by the first aspect of the present invention, which is located in the reaction chamber and is used to support the substrate for depositing thin films.

[0018] Furthermore, in some embodiments of the present invention, the semiconductor device further comprises: a radio frequency power supply, providing a high frequency power signal to the reaction chamber; and a power electrode, disposed at the upper part of the reaction chamber, receiving the high frequency power signal and forming a high frequency electric field with a frequency range of 2 MHz to 100 MHz with the ground electrode, so as to ionize the process gas and deposit a thin film on the surface of the substrate, wherein the heating plate structure is applied to the high frequency electric field so that the total impedance in the tray body and the buried depth of the ground electrode conform to the following rule:

[0019]

[0020] Among them, Z total represents the total impedance of the heating plate structure, Z C represents the capacitive reactance and Z L represents the loop inductive reactance and Z L =ωL, ω represents the angular frequency of the alternating current, C is the capacitance, d represents the buried depth of the grounding electrode, ε represents the dielectric constant of the medium between the grounding electrode and the upper surface of the tray body, S represents the area of ​​the grounding electrode, L is the inductance, and Z L Greater than Z C , Z total is positive, the greater the buried depth d of the corresponding grounding electrode, the greater the total impedance Z total The smaller it is, the greater the current in the tray body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0022] Figure 1 A schematic structural diagram of a semiconductor device provided according to some embodiments of the present invention is shown;

[0023] Figure 2 A schematic structural diagram of a heating plate structure provided according to some other embodiments of the present invention is shown;

[0024] Figure 3A , 3B3C respectively show three shapes of ground electrodes provided according to some embodiments of the present invention;

[0025] Figure 4 A schematic diagram showing a mesh structure of a ground electrode provided in some embodiments of the present invention; and

[0026] Figure 5 A schematic structural diagram of a depth variation region in a ground electrode provided according to some embodiments of the present invention is shown.

[0027] Reference numerals:

[0028] 10. Semiconductor equipment;

[0029] 100 heating plate structure;

[0030] 110 tray body;

[0031] 111 upper surface;

[0032] 120 ground electrode;

[0033] 121 reticular structure;

[0034] 122 Depth Variation Area;

[0035] 130 Power electrode;

[0036] 140 plasma;

[0037] d1 first embedment depth;

[0038] d2 second embedment depth; and

[0039] Δd Depth difference. DETAILED DESCRIPTION

[0040] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0043] It is understood that although the terms "first", "second", "third", etc. may 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 may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0044] As mentioned above, in the prior art, the structure and arrangement of the ground electrode in the heating plate are limited, and it is impossible to ensure that the reaction conditions are consistent across the entire substrate surface, thereby obtaining a uniform film. Currently, the heating plate in the PECVD equipment cannot reduce the uniformity of the film deposited on the substrate surface to less than 1.2%.

[0045] In order to solve the above problems existing in the prior art, the present invention provides a heating plate structure and a semiconductor device, which can significantly improve the overall uniformity of thin film deposition.

[0046] In some non-limiting embodiments, the heating plate structure provided by the first aspect of the present invention may be configured in the semiconductor device provided by the second aspect of the present invention.

[0047] The working principle of the above-mentioned heating plate structure will be described below in conjunction with some embodiments of semiconductor devices. Those skilled in the art will understand that these embodiments of semiconductor devices are only some non-limiting implementations provided by the present invention, which are intended to clearly demonstrate the main concept of the present invention and provide some specific solutions that are convenient for the public to implement, rather than to limit all working modes or all functions of the heating plate structure. Similarly, the heating plate structure is also only a non-limiting implementation provided by the present invention, and does not constitute a limitation on other configuration objects in these semiconductor devices.

[0048] Please see Figure 1 , Figure 1 A schematic structural diagram of a semiconductor device provided according to some embodiments of the present invention is shown.

[0049] like Figure 1 As shown, in some embodiments of the present invention, the semiconductor device 10 may include a reaction chamber for providing a reaction space for thin film deposition, and the upper part of the interior of the reaction chamber may include an air inlet for introducing process gas. A heating plate structure 100 may be included inside the reaction chamber for supporting a substrate for thin film deposition. By adopting the heating plate structure 100 provided by the present invention, the thickness of the thin film deposited on the substrate can reach a target uniform thickness.

[0050] Optionally, the semiconductor device may specifically be a PECVD device to perform capacitively coupled plasma (CCP) discharge in a reaction chamber to activate the process gas so that the gas is deposited on the substrate surface to form a thin film.

[0051] Specifically, if Figure 1 As shown, in the semiconductor device 10, a radio frequency power supply may also be included to provide a high-frequency power signal to the reaction chamber. The heating disk structure 100 may include a ground electrode 120. The upper part of the reaction chamber may include a power electrode 130 for receiving a high-frequency power signal and forming a high-frequency electric field with a frequency range of 2MHz to 100MHz with the ground electrode 120 in the heating disk structure 100. When the intensity of the high-frequency electric field is high enough, it will cause the gas molecules to ionize and generate plasma 140 to activate the process gas and deposit it on the substrate surface. In this embodiment, the ground electrode 120 provides a stable potential reference point so that the plasma 140 can continue to exist between the two electrodes to maintain the stable discharge of the plasma 140.

[0052] Furthermore, if Figure 1As shown, in some embodiments of the present invention, the heating plate structure 100 may include a tray body 110 for supporting a substrate for thin film deposition. A ground electrode 120 may be provided inside the tray body 110 for conducting radio frequency energy. Furthermore, the ground electrode 120 in the tray body 110 may also be connected to a heating system for maintaining the substrate at a specific temperature to optimize the growth characteristics and quality of the thin film.

[0053] In some embodiments, the ground electrode 120 can be made of a metal material having a thermal expansion coefficient similar to that of the tray body 110. Alternatively, the tray body 110 can be made of one or more ceramic materials. The lower the temperature of the heating plate structure 100 made of ceramic material, the faster the film deposition rate. Correspondingly, at this time, the ground electrode 120 can be made of other metal materials such as molybdenum metal, tungsten metal, etc., whose thermal expansion coefficient is basically similar to that of ceramic materials, so as to conduct radio frequency energy.

[0054] Furthermore, if Figure 1 As shown, the ground electrode 120 includes a first area with a first buried depth d1 and a second area with a second buried depth d2, and the second buried depth d2 is greater than the first buried depth d1, which is used to compensate for the extreme difference in film thickness caused by the flow rate difference of the process gas distributed in different areas on the surface of the heating disk structure 100, thereby improving the uniformity of the thin film deposited on the substrate surface.

[0055] Specifically, see Figure 2 , Figure 2 A schematic structural diagram of a heating plate structure provided according to some other embodiments of the present invention is shown.

[0056] like Figure 2 As shown, in some optional embodiments, the first area can be located in the central area of ​​the ground electrode 120 and aligned with the air inlet above the heating disk structure 100. The second area can be located in the edge area of ​​the ground electrode 120 and away from the air inlet. Since the flow rate of the process gas on the upper surface of the heating disk structure 100 corresponding to the first area is usually greater than the flow rate of the process gas on the upper surface of the heating disk structure 100 corresponding to the second area, the electrode embedding depth of the first area and the second area of ​​the ground electrode 120 can be adjusted to adjust the deposition current in the first area and the second area.

[0057] Specifically, in some embodiments of the present invention, the ground electrode 120 can be applied to a high-frequency electric field with a frequency range of 2 MHz to 100 MHz. At this time, the total impedance in the tray body 110 and the buried depth of the ground electrode 120 can conform to the following rules:

[0058]

[0059] Among them, Z total represents the total impedance of the heating plate structure, Z C represents the capacitive reactance and Z L represents the loop inductive reactance and Z L =ωL, ω represents the angular frequency of the alternating current, C represents the capacitance, d represents the burial depth of the grounding electrode, ε represents the dielectric constant of the medium between the grounding electrode and the upper surface of the tray body, S represents the area of ​​the grounding electrode, and L represents the inductance.

[0060] According to the capacitive reactance formula: When the buried depth d of the ground electrode increases, the capacitance C decreases, and the corresponding capacitive reactance Z C The larger the inductive reactance, the larger the Z L =ωL, the larger the inductance L is, or the higher the angular frequency ω of the alternating current is, the corresponding inductive reactance Z L The bigger.

[0061] In this regard, in the high frequency range of 2MHz to 100MHz, Z L Greater than Z C , Z total is positive. At this time, the greater the embedding depth d of the ground electrode 120 is, the greater the total impedance Z in the heating disk structure 100 is. total The smaller the current is, the larger the current in the tray body 110 is. Therefore, it is explained that the heating power of the heating disk structure 100 can be changed by adjusting the embedding depth of the ground electrode 120 in the tray body 110, thereby directly adjusting the deposited film thickness. The larger the current in the tray body 110 is, the greater the thickness of the film deposited on the substrate surface thereon is.

[0062] Furthermore, according to the total impedance Z in the tray body 110 total The relationship between the embedding depth d of the ground electrode 120 can determine that if the embedding depth of the ground electrode 120 is uneven, the current distribution in the tray body 110 is uneven, which will directly affect the uniformity of the generated plasma 140, thereby causing the uniformity of the deposited film to deteriorate.

[0063] Further, in some embodiments, the depth difference Δd obtained by subtracting the first embedding depth d1 from the second embedding depth d2 may be less than the first preset depth difference and greater than the second preset depth difference. Optionally, the first preset depth difference may be preferably 0.3 mm, and the second preset depth difference may be preferably 0.1 mm, so that the depth difference Δd of the embedding depth from the second area and the first area in the ground electrode 120 to the upper surface 111 of the tray body 110 is between 0.1 mm and 0.3 mm. If the depth difference Δd is greater than 0.3 mm or less than 0.1 mm, it is easy to cause a large film thickness difference between the central area and the edge area of ​​the thin film deposited on the surface of the substrate, resulting in poor uniformity of the thin film. In addition, when the depth difference Δd is less than 0.3 mm, the uniformity of the thin film deposited on the surface of the substrate can be further reduced to less than 0.8%.

[0064] In addition, see Figure 3A , 3B 、3C, Figure 3A , 3B 3C respectively show three shapes of ground electrodes provided according to some embodiments of the present invention.

[0065] like Figure 3A As shown, in some optional embodiments, the ground electrode 120 can be configured to be a first shape such as a bowl with a concave center, that is, the first area corresponding to the above is located in the central area of ​​the ground electrode 120, and the second area is located in the edge area of ​​the ground electrode 120. The ground electrode 120 of the first shape can be used to reduce the thickness of the film deposited in the central area of ​​the substrate to improve the extreme difference in film thickness between the center and the edge of the film.

[0066] Alternatively, if Figure 3B As shown, in other embodiments, the process parameters in the reaction chamber can be adjusted, such as reducing the pressure in the reaction chamber, to speed up the flow rate of the process gas, so that the gas flow and plasma distribution in the central area of ​​the substrate are more uniform and sufficient than those in the edge area, so that the deposition rate in the central area may be faster, which will cause the central area of ​​the film to be thinner and the edge area to be thicker. At this time, the ground electrode 120 can also be set to a second shape with a central protrusion such as an inverted bowl. In this embodiment, the central area of ​​the ground electrode 120 is used as the second area, and its edge area is used as the first area, so that the second burial depth d2 of the central area is greater than the first burial depth d1 of the edge area, thereby increasing the deposition current in the central area. The second shape of the ground electrode 120 can be used to increase the thickness of the film deposited in the central area of ​​the substrate to improve the extreme difference in film thickness between the center and the edge of the film.

[0067] In some other optional embodiments, Figure 3CAs shown, the ground electrode 120 can also be a third shape with continuous undulations. Generally speaking, a continuously undulating ground electrode 120 will lead to poor uniformity of the film, but in the film deposition process of some special process materials, if there is no fixed regularity between the original deposited film thickness difference of the film and its deposition area, the third shape of the ground electrode 120 can also be used to specifically weaken the extreme difference in film thickness of the entire area of ​​the substrate surface.

[0068] Further, in some preferred embodiments, the ground electrode 120 is Figure 3A The first shape in Figure 3B When the second shape is obtained, in order to better control the shape of the ground electrode 120, the angle between the edge of the ground electrode 120 and the upper surface 111 of the tray body 110 can be set in the range of 30° to 160°. If the angle between the two is too large or too small, it is easy to cause the ground electrode 120 to have an unexpected deformation, thereby causing the uniformity of the film to deteriorate.

[0069] In addition, in the above embodiment, the first embedding depth d1 of the first region in the ground electrode 120 may be 1.1 mm. If the first embedding depth of the first region in the ground electrode 120 is too shallow, it is easy to cause electrostatic force on the upper surface 111 of the tray body 110, thereby causing the particle size (particle) on the deposited film and the uniformity of the film to deteriorate.

[0070] Next, see Figure 4 , Figure 4 A schematic diagram showing a mesh structure of a ground electrode provided according to some embodiments of the present invention is shown.

[0071] like Figure 4 As shown, in some embodiments, the ground electrode 120 can be configured as a mesh structure 121, and the spacing of the meshes can be in the range of 1 to 10 mm. The smaller the gap between the mesh structures in the ground electrode 120, the better the RF energy can be extracted, thereby improving the uniformity of film formation.

[0072] For further information, see Figure 5 , Figure 5 A schematic structural diagram of a depth variation region in a ground electrode provided according to some embodiments of the present invention is shown.

[0073] like Figure 5As shown, in some embodiments, the diameter of the ground electrode 120 may be greater than the diameter of the substrate and smaller than the diameter of the tray body 110. Optionally, generally speaking, the diameter of the tray body 110 in the heating plate structure 100 is generally about 330 mm, and the diameter of the substrate is generally about 300 mm. Therefore, the diameter of the ground electrode 120 may be greater than 300 mm and less than 330 mm, and the distance h between the depth change region 122 in the ground electrode 120 and the edge of the ground electrode 120 may be 3 to 15 mm, thereby ensuring that the RF energy can be completely extracted. If the distance h between the depth change region 122 in the ground electrode 120 and the edge of the ground electrode 120 is less than 3 mm, it is easy to reduce the RF extraction rate.

[0074] According to the embodiments listed above, by adjusting the difference in embedding depth between the first area and the second area of ​​the ground electrode 120 embedded in the tray body 110 and its shape, the thickness of each area of ​​the thin film deposited on the substrate supported on the heating disk structure 100 can be specifically controlled to improve the uniformity of the thin film deposited on the substrate surface.

[0075] Furthermore, in some comparative test embodiments, the process parameters of the thin film obtained by the above heating disk structure provided by the present invention and the existing heating disk structure are compared. The comparative test is mainly carried out on the structural setting of the ground electrode in the existing heating disk structure and its corresponding deposition film parameters, and the structural setting of the ground electrode 120 in the heating disk structure 100 of the present invention and its corresponding deposition film parameters.

[0076] Specifically, in some test examples, the average burial depth of the ground electrode in the existing heating disk structure to the upper surface of the tray body is maintained to be basically the same as the average burial depth of the ground electrode in the heating disk structure of the present invention to the upper surface of the tray body. However, in the existing heating disk structure, the depth difference Δd between the second burial depth d2 of the second area in the ground electrode and the first burial depth d1 of the first area is greater than 0.3 mm, for example, it can be 0.32 mm, 0.41 mm, etc. At this time, the uniformity of the thin film deposited by the existing heating disk structure is about 1.2%, and it cannot be further reduced. In addition, the difference between the maximum and minimum values ​​of the deposited film thickness, that is, the extreme difference in film thickness, is also large. For example, in In the heating disk structure 100 provided by the present invention, the depth difference Δd between the second buried depth d2 of the second region and the first buried depth d1 of the first region in the ground electrode 120 is maintained within 0.3 mm. At this time, the uniformity of the thin film deposited by the heating disk structure 100 is significantly improved, and the uniformity of the thin film is reduced to less than 1%, and can even be reduced to less than 0.8%. In addition, in comparison, the extreme difference in the thickness of the deposited thin film can also be further reduced.

[0077] Furthermore, the method for calculating the uniformity of the film may include the following steps: selecting n measuring points in the film, and obtaining the film thickness x of the n measuring points. n Calculate the standard deviation σ of the film thickness at n measuring points and the average film thickness at n measuring points Then use the uniformity calculation formula: The uniformity of the film at n measurement points can be obtained. For example, in the above test example, 49 measurement points can be selected to obtain the uniformity (NU%) of the film thickness.

[0078] Therefore, based on multiple test examples of the above-mentioned traditional heating plate structure and the heating plate structure in the present invention, it can be concluded that by controlling the range of the depth difference Δd between the second burial depth d2 of the second area in the ground electrode 120 to the upper surface 111 of the tray body 110 and the first burial depth d1 of the first area, the uniformity of film formation can be improved, the extreme difference of the film can be reduced, and thus the quality of the film can be improved.

[0079] Those skilled in the art can understand that the above-mentioned scheme of the ground electrode 120 including the first region and the second region with two different buried depths is only a non-limiting implementation method provided by the present invention, which is intended to clearly demonstrate the main concept of the present invention and provide a specific scheme that is convenient for the public to implement, rather than to limit the protection scope of the present invention. Optionally, in other embodiments, those skilled in the art can also divide the ground electrode 120 into multiple different buried depths for multiple regions in the thin film based on the concept of the present invention, so as to adjust the local deposition current in a targeted manner, thereby compensating the film thickness.

[0080] In summary, the present invention provides a heating plate structure and a semiconductor device, which can significantly improve the overall uniformity of thin film deposition.

[0081] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may 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 examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A heating plate structure for improving the uniformity of a thin film, characterized in that: include: The tray body is located in the reaction chamber and is used to support the substrate for thin film deposition; as well as A grounding electrode is disposed inside the tray body and is used to derive radio frequency energy, wherein the grounding electrode includes a first area with a first burial depth and a second area with a second burial depth, and the second burial depth is greater than the first burial depth.

2. The heating plate structure according to claim 1, characterized in that: The first area is located in the central area of ​​the ground electrode and is aligned with the air inlet above the heating plate structure, and the second area is located in the edge area of ​​the ground electrode and is away from the air inlet.

3. The heating plate structure according to claim 1, characterized in that: The depth difference obtained by subtracting the first embedding depth from the second embedding depth is smaller than the first preset depth difference and larger than the second preset depth difference.

4. The heating plate structure according to claim 3, characterized in that: The first preset depth difference is 0.3 mm, and the second preset depth difference is 0.1 mm.

5. The heating plate structure according to claim 1, characterized in that: The ground electrode includes any one of a first shape with a center concave, a second shape with a center convex, and a third shape with continuous undulations.

6. The heating plate structure according to claim 5, characterized in that: The ground electrode is in the first shape or the second shape, and an angle between an edge of the ground electrode and an upper surface of the tray body is in a range of 30° to 160°.

7. The heating plate structure according to claim 2, characterized in that: The diameter of the ground electrode is larger than the diameter of the substrate and smaller than the diameter of the tray body, wherein the distance between the depth variation region in the ground electrode and the edge of the ground electrode is 3-15 mm.

8. The heating plate structure according to claim 1, characterized in that: The heating plate structure is applied to a high frequency electric field in the frequency range of 2 MHz to 100 MHz, so that the total impedance in the tray body and the buried depth of the ground electrode conform to the following rules: Among them, Z total represents the total impedance of the heating plate structure, Z C represents the capacitive reactance and Z L represents the loop inductive reactance and Z L =ωL, ω represents the angular frequency of the alternating current, C is the capacitance, d represents the buried depth of the grounding electrode, ε represents the dielectric constant of the medium between the grounding electrode and the upper surface of the tray body, S represents the area of ​​the grounding electrode, L is the inductance, and Z L Greater than Z C , Z total is positive, the greater the buried depth d of the corresponding grounding electrode, the greater the total impedance Z total The smaller it is, the greater the current in the tray body.

9. A semiconductor device, characterized in that: include: The reaction chamber includes a gas inlet at the top of the interior thereof for introducing process gas; as well as The heating plate structure according to any one of claims 1 to 8 is located in the reaction chamber and is used to support a substrate for depositing a thin film.

10. The semiconductor device according to claim 9, wherein: Also includes: A radio frequency power supply, providing a high frequency power signal to the reaction chamber; as well as The power electrode is disposed at the upper part of the reaction chamber, receives the high-frequency power signal and forms a high-frequency electric field with a frequency range of 2 MHz to 100 MHz with the ground electrode to ionize the process gas and deposit a thin film on the surface of the substrate. The heating plate structure is applied to the high-frequency electric field so that the total impedance in the tray body and the embedding depth of the ground electrode conform to the following rule: Among them, Z total represents the total impedance of the heating plate structure, Z C represents the capacitive reactance and Z L represents the loop inductive reactance and Z L =ωL, ω represents the angular frequency of the alternating current, C is the capacitance, d represents the buried depth of the grounding electrode, ε represents the dielectric constant of the medium between the grounding electrode and the upper surface of the tray body, S represents the area of ​​the grounding electrode, L is the inductance, and Z L Greater than Z C , Z total is positive, the greater the buried depth d of the corresponding grounding electrode, the greater the total impedance Z total The smaller it is, the greater the current in the tray body.

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