Plasma enhanced chemical vapor deposition device

Abstract

The embodiment of the invention relates to the technical field of coating, and provides a plasma enhanced chemical vapor deposition device. The plasma enhanced chemical vapor deposition device comprises a reaction cavity, excitation electrode plates, grounding electrode plates and a gas supply assembly, wherein the excitation electrode plates and the grounding electrode plates are alternately arranged in the reaction cavity at intervals; the gas supply assembly is connected with the reaction cavity and is used for supplying reaction gas to a treatment space; and at least one radio frequency generator and at least one dielectric layer which are connected with the edge of the excitation electrode plate and are used for generating plasma discharge in the processing space. And a processing space is formed between each excitation electrode plate and each grounding electrode plate which are adjacent to each other. The at least one dielectric layer is located on the surface, facing the processing space, of the excitation electrode plate or the grounding electrode plate, and the dielectric layer has non-uniform unit area capacitance, so that plasmas in the processing space are uniformly distributed.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of film coating technology, and in particular, to a plasma enhanced chemical vapor deposition device. Background Art

[0002] Semiconductor or photovoltaic materials are widely used in electronics, new energy and other industries. Semiconductor and photovoltaic materials usually need to be chemically treated before they can be applied to products. Plasma Enhanced Chemical Vapor Deposition (PECVD) technology is one of the chemical treatment methods. Common PECVD devices are of two types: tube type and plate type.

[0003] In the process of realizing the present application, the inventors found that the PECVD devices in the prior art have at least the following problems: Specifically, the traditional plate-type PECVD devices have the problem of low production capacity, and the quality of the film deposited by the traditional tube-type PECVD devices cannot meet the production requirements of high-quality solar cells. Summary of the invention

[0004] An embodiment of the present application provides a plasma enhanced chemical vapor deposition device. The plasma enhanced chemical vapor deposition device includes a reaction chamber, an excitation electrode plate, a ground electrode plate, a gas supply assembly, at least one radio frequency generator, and at least one dielectric layer. The excitation electrode plate and the ground electrode plate are arranged alternately and spaced apart in the reaction chamber, and a processing space is formed between each adjacent excitation electrode plate and ground electrode plate, and the processing space is used to place the substrate to be coated. The gas supply assembly is connected to the reaction chamber for providing reaction gas to the processing space. At least one radio frequency generator is connected to the edge of the excitation electrode plate for generating plasma discharge in the processing space. At least one dielectric layer is located on one or two surfaces of the excitation electrode plate facing the processing space, or, is located on one or two surfaces of the ground electrode plate facing the processing space, and the dielectric layer has a non-uniform unit area capacitance so that the plasma in the processing space is evenly distributed.

[0005] In the PECVD device of the embodiment of the present application, the excitation electrode plate and the grounding electrode plate are arranged alternately and spaced apart in the reaction chamber, so that multiple substrates can be processed simultaneously, the production capacity is significantly improved, and the problem of low production capacity of the traditional plate-type PECVD device is solved. In addition, by connecting the RF generator to the edge of the excitation electrode plate and introducing a dielectric layer with uneven unit area capacitance, the uniformity of the plasma distribution can be improved, thereby improving the uniformity and quality of the deposited film layer, and solving the problem of insufficient film quality of the traditional tubular PECVD device.

[0006] In some embodiments, the thickness of the dielectric layer is non-uniform, so that the dielectric layer has a non-uniform capacitance per unit area.

[0007] In some embodiments, when the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, the thickness of the dielectric layer is largest at the edge of the excitation electrode plate, and the thickness of the dielectric layer gradually decreases in the direction pointing from the edge of the excitation electrode plate to the center; when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space, the thickness of the dielectric layer is largest at the edge of the grounding electrode plate, and the thickness of the dielectric layer gradually decreases in the direction pointing from the edge of the grounding electrode plate to the center.

[0008] In some embodiments, when the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, the surface of the excitation electrode plate facing the processing space is a convex surface, and the dielectric layer includes a concave surface adapted to the convex surface of the excitation electrode plate and a plane opposite to the concave surface; when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space, the surface of the grounding electrode plate facing the processing space is a convex surface, and the dielectric layer includes a concave surface adapted to the convex surface of the grounding electrode plate and a plane opposite to the concave surface.

[0009] In some embodiments, when the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, the dielectric layer completely covers the convex surface of the excitation electrode plate, or the dielectric layer partially covers the convex surface of the excitation electrode plate, and the size of the dielectric layer is not less than the size of the substrate; when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space, the dielectric layer completely covers the convex surface of the grounding electrode plate, or the dielectric layer partially covers the convex surface of the grounding electrode plate, and the size of the dielectric layer is not less than the size of the substrate.

[0010] In some embodiments, when the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, or when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space: along the thickness direction of the dielectric layer, in any cross-section of the dielectric layer, the contour lines of the concave surface are Gaussian distributed.

[0011] In some embodiments, when the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, or when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space: the concave surface of the dielectric layer is formed by multiple steps with gradually decreasing heights.

[0012] In some embodiments, the dielectric layer includes at least one of a solid dielectric layer and a gas dielectric layer.

[0013] In some embodiments, the gas dielectric layer is in communication with the processing volume.

[0014] In some embodiments, the solid dielectric layer has a hollow inner cavity, and the gas dielectric layer fills the inner cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of a plasma enhanced chemical vapor deposition device according to an embodiment of the present application.

[0016] Explanation of the symbols of the main components: PECVD device-10; reaction chamber-11; excitation electrode plate-12; grounding electrode plate-13; gas supply assembly-14; RF generator-15; dielectric layer-16; processing space-S; first direction-D1; second direction-D2; third direction-D3.

[0017] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the present application.

[0019] In the description of the embodiments of the present application, the terms "center", "thickness", "up", "down", "top", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the implementation methods of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0020] In the description of the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0021] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two.

[0022] In the description of the embodiments of the present application, unless otherwise specified, the term "connection" 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 an indirect connection through an intermediate medium; it can be the internal connection between two elements or the interaction relationship between two elements.

[0023] For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] Figure 1 FIG. 1 is a schematic diagram of the structure of a plasma enhanced chemical vapor deposition (PECVD) device according to an embodiment of the present application. Figure 1 As shown, the PECVD device 10 includes a reaction chamber 11, an excitation electrode plate 12, a ground electrode plate 13, a gas supply component 14, a gas exhaust component (not shown), a radio frequency generator 15 and a dielectric layer 16.

[0025] Along the first direction D1, the excitation electrode plates 12 and the grounding electrode plates 13 are alternately arranged in the reaction chamber 11, and a processing space S is formed between each adjacent excitation electrode plate 12 and grounding electrode plate 13. The processing space S is used to place the substrate to be coated.

[0026] The excitation electrode plate 12 and the grounding electrode plate 13 are parallel or approximately parallel. An adjacent excitation electrode plate 12 and a adjacent grounding electrode plate 13 form a parallel plate capacitively coupled plasma electrode pair. The PECVD device 10 includes a plurality of parallel plate capacitively coupled plasma electrode pairs.

[0027] The gas supply assembly 14 is connected to the reaction chamber 11 and is used to provide reaction gas to the processing space S. The gas exhaust assembly is connected to the reaction chamber 11 and is used to exhaust the reaction gas in the reaction chamber 11 .

[0028] There is at least one RF generator 15 , which is connected to the edge of the excitation electrode plate 12 and is used to generate plasma discharge in the processing space S.

[0029] The number of the dielectric layer 16 is at least one. The dielectric layer 16 is located on the surface of the excitation electrode plate 12 facing the processing space S, and the dielectric layer 16 has a non-uniform capacitance per unit area, so that the plasma in the processing space S is evenly distributed.

[0030] It should be noted that the conventional plate-type PECVD device widely used in semiconductor (such as thin film transistor) and photovoltaic fields usually includes an upper electrode plate and a lower electrode plate relative to each other. In order to achieve the best uniformity, the feed point of the excitation power supply is set at the middle position of the top surface of the upper electrode plate, and plasma discharge deposition, etching or other surface treatment is performed only on the upper surface of the lower electrode plate, which limits the production capacity and wastes a lot of space.

[0031] It should also be noted that the deposition rate, uniformity and film quality of the medium / low frequency power supply of the traditional tubular PECVD device cannot reach the deposition level of the radio frequency / very high frequency (RF / VHF) of the plate-type PECVD device, which results in it being limited to the production of traditional photovoltaic passivated emitter and rear cell (Passivated Emitter and Rear Cell, PERC) or tunnel oxide passivated contact (Tunnel Oxide Passivated Contact, TOPCon) cells, and cannot be used in the production of high-quality new heterojunction (Heterojunction with Intrinsic Thin Layer, HJT) solar cells.

[0032] In the PECVD device 10 of the embodiment of the present application, the excitation electrode plate 12 and the grounding electrode plate 13 are arranged alternately and spaced apart in the reaction chamber 11, so that multiple substrates can be processed simultaneously, which significantly improves the production capacity and solves the problem of low production capacity of traditional plate-type PECVD devices.

[0033] In addition, the PECVD device 10 of the embodiment of the present application corrects or improves the uniformity of the plasma electric field distribution by connecting the RF generator 15 to the edge of the excitation electrode plate 12 and introducing a dielectric layer 16 with uneven capacitance per unit area, thereby improving the uniformity and quality of the deposited film layer and solving the problem of insufficient film layer quality in traditional tubular PECVD devices.

[0034] The dielectric layer 16 can be arranged on one side or both sides of the excitation electrode plate 12 or the grounding electrode plate 13. The general principle is to correct the non-uniform electric field in the discharge gap (or processing space S) of the parallel plate capacitive coupled plasma electrode pair to achieve the purpose of forming a uniform electric field and uniform discharge between the discharge gaps.

[0035] Specifically, in a capacitively coupled plasma (CCP) chemical vapor deposition device, the RF voltage distributed at the edge and center of the plasma processing space is uneven during the process of electromagnetic waves generated by the excitation power supply (also known as the RF generator) propagating simultaneously along the two surfaces of the excitation electrode plate. If the RF power supply is connected to the edge of the excitation electrode plate, the RF voltage decreases slightly from the edge to the center of the excitation electrode plate.

[0036] As mentioned above, one method to restore the (substantially) uniform RF voltage at the edge and center of the plasma itself is as follows: a capacitor is introduced between the excitation electrode plate 12 and the ground electrode plate 13, and the capacitor is connected in series with the plasma and the substrate in the reaction chamber 11.

[0037] More specifically, in the PECVD device 10, the excitation electrode plate 12, the ground electrode plate 13 and the plasma are all conductors, a capacitor is formed between the excitation electrode plate 12 and the plasma, and a capacitor is formed between the plasma and the ground electrode plate 13. Due to the introduction of the dielectric layer 16, the capacitance between the plasma and the ground electrode plate 13 is changed, or an additional capacitor is introduced. This additional capacitor is inserted between the substrate and the electrode plate (at Figure 1 The middle part is the excitation electrode plate 12), which divides a part of the voltage drop between the parallel plate capacitively coupled plasma electrode pair, thereby achieving uniform electric field discharge between the entire parallel plate capacitively coupled plasma electrode pair.

[0038] This additional capacitor adjusts the local RF power distribution to compensate for the process non-uniformity caused by, for example, gas composition non-uniformity, edge effect or temperature gradient. For example, the edge power supply of the excitation electrode plate 12 will generate standing waves, resulting in an uneven electric field in the processing space S, and the dielectric layer 16 acts as a capacitive voltage divider to compensate for this non-uniformity and make the plasma discharge more uniform.

[0039] In some embodiments, different shapes of the excitation electrode plate 12 or the grounding electrode plate 13 may be used, such as circular, square, etc., to accommodate different substrate sizes and shapes.

[0040] In some embodiments, the gas supply assembly 14 may adopt different gas supply modes, such as spray mode, diffusion mode, etc., to optimize gas distribution. For example, the gas supply assembly 14 includes a gas source and a uniform gas spray box connected to the gas source and the reaction chamber 11. The gas source provides reaction gas to the interior of the reaction chamber 11 through the uniform gas spray box, and generates plasma through radio frequency discharge.

[0041] In some embodiments, the gas exhaust assembly includes, for example, a vacuum pump connected to the reaction chamber 11. The vacuum pump extracts the reacted gas from the lower part of the electrode plate array out of the reaction chamber 11.

[0042] In some embodiments, the RF generator 15 may use different RF frequencies and powers, such as a VHF excitation power source of 13.56 MHz or higher, to optimize the plasma characteristics.

[0043] In some embodiments, the substrate is located on a surface of the excitation electrode plate 12 facing the processing space S.

[0044] In some other embodiments, the substrate is located on the surface of the ground electrode plate 13 facing the processing space S.

[0045] In some embodiments, the substrate is substantially plate-shaped. During plasma processing, the substrate is perpendicular to the first direction D1 and parallel or substantially parallel to a plane formed by the second direction D2 and the third direction D3. The first direction D1, the second direction D2, and the third direction D3 are perpendicular to each other.

[0046] Figure 1 Schematically shows an excitation electrode plate 12, two grounding electrode plates 13, a radio frequency generator 15 and two dielectric layers 16. A processing space S is formed between the excitation electrode plate 12 and two adjacent grounding electrode plates 13, and a dielectric layer 16 is provided on two opposite surfaces of the excitation electrode plate 12.

[0047] In other embodiments, the number of the excitation electrode plates 12, the grounding electrode plates 13, the RF generators 15 and the dielectric layer 16 is not limited to the above. For example, there are at least two excitation electrode plates 12, and at least one grounding electrode plate 13. Along the first direction D1, the excitation electrode plates 12 and the grounding electrode plates 13 are spaced and alternately distributed. Alternatively, there are multiple RF generators 15, and each RF generator 15 can be connected to one or more excitation electrode plates 12. Alternatively, the dielectric layer 16 is located on a surface of the excitation electrode plate 12 facing the processing space S; alternatively, the dielectric layer 16 is located on two surfaces of the grounding electrode plate 13 facing the processing space S; alternatively, the dielectric layer 16 is located on a surface of the grounding electrode plate 13 facing the processing space S.

[0048] In some embodiments, the thickness of the dielectric layer 16 is non-uniform, so that the dielectric layer 16 has a non-uniform capacitance per unit area to compensate for the non-uniform voltage distribution on the processing space S. Therefore, by changing the thickness of the dielectric layer 16 to control the capacitance per unit area of ​​the dielectric layer 16, it is beneficial to flexibly control the distribution of the capacitance per unit area of ​​the dielectric layer 16, so as to more accurately compensate for the electromagnetic non-uniformity during the plasma processing. In some embodiments, one surface of the dielectric layer 16 is planar, and the other surface has a non-planar shape, so that the thickness of the dielectric layer 16 is non-uniform.

[0049] In some embodiments, the dielectric layer 16 is thickest at the position of the electromagnetic standing wave in the processing space S, which is located at the position where the RF generator 15 is connected to the excitation electrode plate 12, that is, corresponding to the edge position of the excitation electrode plate 12. And the thickness of the dielectric layer 16 gradually decreases from the edge of the excitation electrode plate 12 to the center of the excitation electrode plate 12. Therefore, if the electromagnetic traveling waves induced in the processing space S combine with each other near the edge of the excitation electrode plate 12 to form a standing wave, and the standing wave has a maximum voltage near the edge of the excitation electrode plate 12, then the thickness of the dielectric layer 16 will be greater near the edge of the excitation electrode plate 12 than at the center of the excitation electrode plate 12.

[0050] In some embodiments, the dielectric layer 16 is located on the surface of the excitation electrode plate 12 facing the processing space S, the thickness of the dielectric layer 16 is largest at the edge of the excitation electrode plate 12, and the thickness of the dielectric layer 16 gradually decreases in the direction from the edge of the excitation electrode plate 12 to the center.

[0051] In other embodiments, the dielectric layer 16 is located on the surface of the grounding electrode plate 13 facing the processing space S, the thickness of the dielectric layer 16 is largest at the edge of the grounding electrode plate 13, and the thickness of the dielectric layer 16 gradually decreases in the direction pointing from the edge of the grounding electrode plate 13 to the center.

[0052] Therefore, in order to solve the problem of too high edge electric field strength caused by the RF generator 15 supplying power to the edge of the excitation electrode plate 12, by providing a thicker dielectric layer 16 at the edge of the excitation electrode plate 12 and / or the grounding electrode plate 13, the electric field strength at the edge of the excitation electrode plate 12 and / or the grounding electrode plate 13 can be reduced, so that the electric field distribution is more uniform. In addition, the dielectric layer 16 with thick edges and thin center is conducive to effectively suppressing the generation of standing waves, and further improving the uniformity of plasma.

[0053] In some embodiments, the rate at which the thickness of the dielectric layer 16 decreases may be adjusted according to specific process parameters and the size of the excitation electrode plate 12 or the ground electrode plate 13 to obtain optimal uniformity.

[0054] In some embodiments, the excitation electrode plate 12 has a non-planar surface facing the processing space S, and the dielectric layer 16 is located on the surface of the excitation electrode plate 12 facing the processing space S.

[0055] Specifically, the surface of the excitation electrode plate 12 facing the processing space S is a convex surface, and the dielectric layer 16 includes a concave surface adapted to the convex surface of the excitation electrode plate 12 and a flat surface opposite to the concave surface. Therefore, the cooperation between the convex surface of the excitation electrode plate 12 and the concave surface of the dielectric layer 16 can improve the stability of the structure, prevent the dielectric layer 16 from falling off, and facilitate processing.

[0056] In some other embodiments, the ground electrode plate 13 has a non-planar surface facing the processing space S, and the dielectric layer 16 is located on the surface of the ground electrode plate 13 facing the processing space S.

[0057] Specifically, the surface of the ground electrode plate 13 facing the processing space S is a convex surface, and the dielectric layer 16 includes a concave surface adapted to the convex surface of the ground electrode plate 13 and a flat surface opposite to the concave surface. Therefore, the cooperation between the convex surface of the ground electrode plate 13 and the concave surface of the dielectric layer 16 can improve the stability of the structure, prevent the dielectric layer 16 from falling off, and facilitate processing.

[0058] In some embodiments, the dielectric layer 16 may adopt different concave shapes or adjust the curvature of the concave surface according to specific process parameters and the size of the excitation electrode plate 12 or the grounding electrode plate 13 to obtain optimal electric field uniformity.

[0059] In some embodiments, the dielectric layer 16 is located on the surface of the excitation electrode plate 12 facing the processing space S, the dielectric layer 16 completely covers the convex surface of the excitation electrode plate 12, or the dielectric layer 16 partially covers the convex surface of the excitation electrode plate 12, and the size of the dielectric layer 16 is not less than the size of the substrate.

[0060] This helps ensure that the dielectric layer 16 covers the area where the substrate is located, ensuring that the plasma uniformity on the substrate surface is effectively adjusted. When the dielectric layer 16 partially covers the convex surface of the excitation electrode plate 12 and the size of the dielectric layer 16 is not less than the size of the substrate, it can also reduce material usage and reduce costs.

[0061] In other embodiments, the dielectric layer 16 is located on the surface of the ground electrode plate 13 facing the processing space S, the dielectric layer 16 completely covers the convex surface of the ground electrode plate 13, or the dielectric layer 16 partially covers the convex surface of the ground electrode plate 13, and the size of the dielectric layer 16 is not less than the size of the substrate.

[0062] Similarly, the position setting of the above-mentioned dielectric layer 16 is conducive to ensuring that the dielectric layer 16 covers the area where the substrate is located, ensuring that the plasma uniformity on the substrate surface is effectively adjusted. When the dielectric layer 16 partially covers the convex surface of the ground electrode plate 13 and the size of the dielectric layer 16 is not less than the size of the substrate, the material usage can also be reduced and the cost can be reduced.

[0063] In some embodiments, the dielectric layer 16 is located on the surface of the excitation electrode plate 12 facing the processing space S or the dielectric layer 16 is located on the surface of the grounding electrode plate 13 facing the processing space S, and along the thickness direction of the dielectric layer 16, in any cross section of the dielectric layer 16, the contour line of the concave surface is Gaussian distributed. Therefore, the Gaussian distribution contour line of the dielectric layer 16 can achieve a smooth transition of the electric field strength, reduce the sudden change of the electric field, and thus improve the uniformity of the plasma.

[0064] In some embodiments, the parameters of the Gaussian distribution of the concave surface of the dielectric layer 16, such as the standard deviation and the center position, may be adjusted according to specific process parameters and the size of the excitation electrode plate 12 or the ground electrode plate 13 to obtain optimal electric field uniformity.

[0065] In some embodiments, the dielectric layer 16 is located on the surface of the excitation electrode plate 12 facing the processing space S, or the dielectric layer 16 is located on the surface of the grounding electrode plate 13 facing the processing space S, and the concave surface of the dielectric layer 16 is formed by multiple steps with gradually decreasing heights.

[0066] Therefore, it is easier to manufacture and control the dielectric layer 16 to have a stepped structure than the Gaussian distribution contour of the dielectric layer 16. In addition, the stepped structure can achieve the effect of Gaussian distribution and improve the uniformity of plasma to a certain extent.

[0067] In some embodiments, the number and height of the steps forming the concave surface of the dielectric layer 16 can be adjusted according to specific process parameters and the size of the excitation electrode plate 12 or the grounding electrode plate 13 to obtain optimal electric field uniformity.

[0068] In some embodiments, the dielectric layer 16 includes at least one of a solid dielectric layer and a gas dielectric layer, thereby increasing the flexibility of material selection for the dielectric layer 16 .

[0069] In some embodiments, the material of the solid dielectric layer is selected from one or a combination of ceramic, quartz, Teflon, and glass, but is not limited thereto.

[0070] In some embodiments, the material of the gas dielectric layer may be selected from air or reactive gas, but is not limited thereto.

[0071] In some embodiments, the gas dielectric layer is connected to the processing space S. Thus, the structural design of the PECVD device 10 can be simplified and the manufacturing cost can be reduced. In addition, the dielectric properties of the gas dielectric layer can be dynamically adjusted by adjusting the gas composition and pressure of the processing space S to achieve more precise electric field control.

[0072] Specifically, the dielectric layer 16 is a gas dielectric layer, one of the excitation electrode plate 12 and the grounding electrode plate 13 is a flat plate structure, and the other is a flying saucer structure, so that the discharge gap size between the excitation electrode plate 12 and the grounding electrode plate 13 is non-constant, which plays the effect of correcting the uneven electric field.

[0073] It should be noted that the flat plate structure refers to the two relative surfaces of the electrode plate facing the processing space S being flat, and the flying saucer structure refers to the two relative surfaces of the electrode plate facing the processing space S being convex, and the electrode plate is thick in the middle and thin at the edges.

[0074] In some embodiments, the solid dielectric layer has a hollow inner cavity, and the gas dielectric layer is filled in the inner cavity. Thus, the dielectric layer 16 can combine the advantages of solid dielectric materials and gas dielectric materials, the solid dielectric layer provides structural support, and the gas dielectric layer provides adjustable dielectric properties. In addition, the overall dielectric properties of the dielectric layer 16 can be flexibly adjusted by adjusting the composition and pressure of the gas in the inner cavity of the solid dielectric layer.

[0075] In some embodiments, different inner cavity shapes (eg, circular, square, etc.) can be designed according to specific process parameters and the size of the excitation electrode plate 12 or the grounding electrode plate 13, and the size of the hollow inner cavity can be adjusted to flexibly control the electric field distribution.

[0076] In other embodiments, the implementation method of the dielectric layer 16 having a non-uniform capacitance per unit area is not limited to the above, and is described below with examples.

[0077] In some embodiments, the dielectric layer 16 has a non-uniform capacitance per unit area by changing the material composition of the dielectric layer 16. For example, the dielectric layer 16 may be composed of two or more materials with different dielectric constants, and a material with a high dielectric constant is used in an area where the plasma density needs to be enhanced, and a material with a low dielectric constant is used in an area where the plasma density needs to be reduced. These materials may exist in a layered structure, a gradient structure, or a mixed structure. For another example, impurities of different concentrations are doped in the dielectric material forming the dielectric layer 16 to change the local dielectric constant, thereby forming the desired non-uniform capacitance per unit area to compensate for the non-uniform voltage distribution on the processing space S.

[0078] In some embodiments, the dielectric layer 16 may have a non-uniform capacitance per unit area by changing the surface structure of the dielectric layer 16. For example, microstructures such as microgrooves and micropillars may be fabricated on the surface of the dielectric layer 16. These microstructures may change the distribution of the capacitance per unit area of ​​the dielectric layer 16, thereby compensating for the non-uniform voltage distribution on the processing space S.

[0079] In summary, the PECVD device of the embodiment of the present application expands the production capacity of the traditional plate-type PECVD device by arranging the excitation electrode plates and the grounding electrode plates in an array.

[0080] In addition, in the PECVD device of the embodiment of the present application, the radio frequency generator can use an RF / VHF power supply to excite the gas to generate a high-density, low-ion bombardment energy plasma, thereby improving the quality of traditional tubular PECVD plasma deposition or processing.

[0081] In addition, in the PECVD device of the embodiment of the present application, the excitation electrode plate or the grounding electrode plate is a disc-shaped structure, and a dielectric layer is used to compensate and fill the disc-shaped structure, so as to correct the standing wave formed by connecting the RF generator at the edge of the RF electrode plate, including other edge effects such as telegraph effect, electrostatic field edge effect, uneven gas or temperature distribution, etc., so as to form a uniform plasma in the discharge gap of the electrode plate.

[0082] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A plasma enhanced chemical vapor deposition device, characterized in that: include: reaction chamber; The excitation electrode plates and the grounding electrode plates are arranged alternately and at intervals in the reaction chamber, and a processing space is formed between each adjacent excitation electrode plate and the grounding electrode plate, and the processing space is used to place the substrate to be coated; A gas supply assembly, connected to the reaction chamber, for supplying reaction gas to the processing space; at least one radio frequency generator connected to an edge of the excitation electrode plate and configured to generate a plasma discharge in the processing space; as well as At least one dielectric layer is located on one or both surfaces of the excitation electrode plate facing the processing space, or on one or both surfaces of the grounding electrode plate facing the processing space, and the dielectric layer has a non-uniform capacitance per unit area so that the plasma in the processing space is evenly distributed.

2. The plasma enhanced chemical vapor deposition device according to claim 1, characterized in that: The thickness of the dielectric layer is non-uniform, so that the dielectric layer has the non-uniform capacitance per unit area.

3. The plasma enhanced chemical vapor deposition device according to claim 2, characterized in that: When the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, the thickness of the dielectric layer is the largest at the edge of the excitation electrode plate, and the thickness of the dielectric layer gradually decreases in the direction from the edge of the excitation electrode plate to the center; When the dielectric layer is located on the surface of the grounding electrode plate facing the processing space, the thickness of the dielectric layer is largest at the edge of the grounding electrode plate, and the thickness of the dielectric layer gradually decreases in the direction from the edge of the grounding electrode plate to the center.

4. The plasma enhanced chemical vapor deposition device according to claim 3, characterized in that: In the case where the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, the surface of the excitation electrode plate facing the processing space is a convex surface, and the dielectric layer includes a concave surface adapted to the convex surface of the excitation electrode plate and a flat surface opposite to the concave surface; When the dielectric layer is located on the surface of the grounding electrode plate facing the processing space, the surface of the grounding electrode plate facing the processing space is a convex surface, and the dielectric layer includes a concave surface adapted to the convex surface of the grounding electrode plate and a plane opposite to the concave surface.

5. The plasma enhanced chemical vapor deposition device according to claim 4, characterized in that: When the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, the dielectric layer completely covers the convex surface of the excitation electrode plate, or the dielectric layer partially covers the convex surface of the excitation electrode plate, and the size of the dielectric layer is not less than the size of the substrate; When the dielectric layer is located on the surface of the grounding electrode plate facing the processing space, the dielectric layer completely covers the convex surface of the grounding electrode plate, or the dielectric layer partially covers the convex surface of the grounding electrode plate, and the size of the dielectric layer is not less than the size of the substrate.

6. The plasma enhanced chemical vapor deposition device according to claim 4, characterized in that: When the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, or when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space: along the thickness direction of the dielectric layer, in any cross section of the dielectric layer, the contour line of the concave surface is Gaussian distributed.

7. The plasma enhanced chemical vapor deposition device according to claim 4, characterized in that: When the dielectric layer is located on the surface of the excitation electrode plate facing the processing space, or when the dielectric layer is located on the surface of the grounding electrode plate facing the processing space: the concave surface of the dielectric layer is formed by a plurality of steps with gradually decreasing heights.

8. The plasma enhanced chemical vapor deposition device according to any one of claims 1 to 7, characterized in that: The dielectric layer includes at least one of a solid dielectric layer and a gas dielectric layer.

9. The plasma enhanced chemical vapor deposition device according to claim 8, characterized in that: The gas dielectric layer is in communication with the processing space.

10. The plasma enhanced chemical vapor deposition device according to claim 8, characterized in that: The solid dielectric layer has a hollow inner cavity, and the gas dielectric layer fills the inner cavity.

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