Large-area uniform-gas cross-electrode plasma ionization device

Abstract

The application discloses a large-area uniform-gas cross electrode plasma ionization device, which comprises a cavity, a carrier plate, a uniform-gas assembly and a cross electrode assembly, an inner auxiliary heating device is arranged around the inside of the cavity, and the carrier plate is arranged below the cavity and used for carrying a substrate to be treated; the uniform-gas assembly is composed of a gas inlet assembly, an upper electrode plate, a uniform-gas plate A, a uniform-gas plate B, a uniform-gas isolation plate and a uniform-gas layering frame, and process gas is uniformly diffused into the inside of the cavity through the multi-layer uniform-gas structure; the cross electrode assembly comprises positive electrode columns and negative electrode columns which are alternately arranged, the positive and negative electrode columns are fixed on the uniform-gas isolation plate made of quartz, and the cross electrode assembly is connected with an external power supply through electrode connecting columns and electrode leading-out columns. A uniform multi-dimensional electric field network is formed through the electrode structure arranged in space, uniform distribution of plasma in the large-area cavity is realized, the plasma generation area and the substrate placing area are decoupled, direct bombardment damage of high-energy particles to the substrate is avoided, and the deposition rate and product yield are improved.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating equipment technology, and in particular to a large-area uniform gas cross electrode plasma ionization device. Background Technology

[0002] Plasma-enhanced chemical vapor deposition (PECVD) is a widely used thin film preparation technology in industry. Its core principle is to generate plasma by exciting process gases with an electric field. The activity of the plasma promotes chemical reactions, thereby depositing a thin film on the substrate surface. Currently, widely used industrial PECVD deposition systems generally employ a parallel plate electrode structure. Specifically, two parallel electrode plates are arranged within the process chamber. The upper electrode plate integrates the process gas spraying function, while the lower electrode plate serves as a grounding device. The substrate to be processed is placed on the lower electrode plate. An RF or VHF power supply is connected to the upper electrode plate through an impedance matching device to excite the gas between the two plates, generating plasma.

[0003] The plasma discharge system with the aforementioned traditional parallel plate electrode structure has the following inherent defects: First, the substrate to be treated inevitably becomes part of the discharge system, and the high-energy particles generated by the plasma will directly bombard the surface of the substrate, causing damage. This damage will seriously affect the product performance, especially for organic sensitive materials. Second, when the substrate to be treated has an irregular structure or features such as sharp points or deep holes, it will seriously interfere with the distribution of the plasma electric field, leading to unstable discharge and even causing ablation damage to the substrate. Third, for large-size substrates and insulating substrates, the discharge spacing of the traditional electrode plates will become a variable, resulting in a significant decrease in the stability of the entire system, or even failure to work properly. Fourth, the edge effect of the parallel plate structure is obvious, and the uniformity of plasma distribution is poor, which limits the yield and process window of large-size substrate coating. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a large-area uniform gas cross-electrode plasma ionization device, which solves the problems existing in the prior art, such as high-energy particle bombardment of substrates, unstable discharge on irregularly shaped substrates, poor adaptability to large-size and sensitive substrates, and uneven plasma distribution.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a large-area uniform gas cross electrode plasma ionization device, comprising a cavity, a carrier plate, a uniform gas assembly, and a cross electrode assembly;

[0006] The carrier plate is disposed inside the cavity at the bottom and supports the substrate to be processed;

[0007] The gas equalization assembly is disposed above the cavity and includes an air inlet assembly, an upper electrode plate, a gas equalization plate A, a gas equalization plate B, a gas equalization isolation plate, and a gas equalization layered frame. The air inlet assembly is disposed above the upper electrode plate to introduce process gas. After entering from the air inlet assembly, the process gas flows sequentially through the upper electrode plate, gas equalization plate B, gas equalization plate A, and gas equalization isolation plate, and finally diffuses evenly into the cavity through the gas equalization holes on the gas equalization isolation plate. The gas equalization isolation plate, gas equalization plate A, and gas equalization plate B are all fixed to the gas equalization layered frame, and the gas equalization layered frame is fixed to the upper electrode plate, forming a stable multi-layered gas equalization structure.

[0008] The cross electrode assembly includes a positive electrode post, a negative electrode post, an electrode connecting post, and an electrode lead-out post. The positive and negative electrode posts are arranged alternately and fixed on the gas-equalizing isolation plate. The positive electrode posts converge on one side and connect to an electrode connecting post, while the negative electrode posts converge on the other side and connect to another electrode connecting post. One end of the electrode connecting post is connected to the electrode lead-out post, and the other end of the electrode lead-out post extends to the outside of the cavity and is connected to a power source.

[0009] Furthermore, the inner wall of the cavity is provided with internal auxiliary heating to provide and maintain the process temperature.

[0010] Furthermore, the gas-uniform isolation plate is made of insulating material, which electrically isolates the positive electrode post from the negative electrode post.

[0011] Furthermore, the electrode lead-out column extends from above the upper electrode plate and is vertically connected to the electrode connecting column; an electrode lead-out isolation sleeve is fitted at the part of the electrode lead-out column that passes through the gas uniform layering frame, a lower isolation sleeve is provided above the gas uniform layering frame, an upper isolation sleeve is nested at the outer end of the electrode lead-out column, and sealing rings are provided on both sides of the lower and upper isolation sleeves to achieve vacuum sealing. Finally, the entire set of electrode columns is fixed to the upper electrode plate by a pressure plate.

[0012] Furthermore, an isolation plate A is fixed on the cavity, and an upper electrode plate is fixed on the isolation plate A. Sealing rings are provided on both the upper and lower surfaces of the isolation plate A. An isolation plate B is provided around the lower part of the upper electrode plate to limit the plasma generation area in the cavity.

[0013] Furthermore, the materials of the gas equalization isolation plate, lower isolation sleeve, isolation plate B, isolation plate A, upper isolation sleeve, and electrode lead-out isolation sleeve are any one of quartz, ceramic, or PEEK insulating materials, and the appropriate material is selected according to different process temperatures and chemical environments.

[0014] Furthermore, the gas equalization plate A, the gas equalization plate B, and the gas equalization isolation plate are all provided with gas equalization holes, which are arranged exponentially according to the cavity size and the arrangement of the substrate to be treated.

[0015] Furthermore, the substrate to be processed is any one of silicon wafers, irregularly shaped structural parts, large-size substrates, insulating material substrates, or organic sensitive material substrates.

[0016] Furthermore, the carrier plate side or the substrate side to be treated is also provided with an independent electric field control unit for regulating the energy of ionized ions, so as to realize independent control of ionization density and ion energy and meet the needs of different processes.

[0017] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:

[0018] 1. By designing the electrodes to be arranged in a cross pattern, a multi-dimensional, interwoven electric field network is formed within the reaction chamber, thereby weakening the edge effect of the parallel plate structure. This allows the electric field and plasma to be more uniformly extended throughout the entire volume of the chamber, significantly improving the plasma uniformity on the substrate plane.

[0019] 2. The complex electric field generated by the cross electrodes changes the trajectory of electrons from simple vertical oscillations to three-dimensional complex motion, which greatly prolongs the movement path and residence time of electrons in the reaction chamber and increases the probability of collision between electrons and reactive gas molecules. Under the same input power, higher gas ionization rate and thin film deposition rate can be obtained.

[0020] 3. The plasma uniformity is significantly less sensitive to geometric parameters such as electrode spacing, which enables the PECVD process to maintain good uniformity over a wider range of reaction pressure, power and gas flow rate. This reduces the difficulty of process debugging and greatly improves the equipment's adaptability to coating large-size substrates and production yield.

[0021] 4. The cross-electrode structure partially decouples the plasma generation area from the substrate placement area in space. Through electrode layout and phase control, high-density plasma can be generated in the center of the cavity, while maintaining a relatively uniform plasma sheath with controllable ion bombardment energy at the substrate position. This reduces the risk of direct damage to the surface of sensitive substrates (such as organic materials and irregular structures) by high-energy ions while ensuring film quality. Furthermore, independent control of ion density and energy can be achieved by introducing an independent electric field to the carrier side. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a schematic diagram of the main structure of a large-area uniform gas cross electrode plasma ionization device according to the present invention;

[0024] Figure 2For the present invention Figure 1 A cross-sectional view along the F direction;

[0025] Figure 3 This is a top view of a large-area uniform gas cross electrode plasma ionization device according to the present invention;

[0026] Figure 4 For the present invention Figure 3 A magnified view of the electrode connection point in the D direction.

[0027] Explanation of markings in the diagram: 1-Cavity, 2-Carrier plate, 3-Silicon wafer, 4-Gas equalization isolation plate, 5-Gas equalization layered frame, 6-Gas equalization plate A, 7-Gas equalization plate B, 8-Inlet assembly, 9-Upper electrode plate, 10-Positive electrode post, 11-Negative electrode post, 12-Electrode connection post, 13-Electrode lead-out post, 14-Lower isolation sleeve, 15-Isolation plate B, 16-Isolation plate A, 17-Internal auxiliary heating, 18-Pressure plate, 19-Upper isolation sleeve, 20-Sealing ring, 21-Electrode lead-out isolation sleeve, 22-Gas equalization hole. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] Example

[0030] refer to Figure 1-4 As shown, a large-area uniform gas cross-electrode plasma ionization device is mainly used in the PECVD coating process of silicon wafers. The specific structure is as follows:

[0031] The cavity 1 is made of stainless steel, and internal auxiliary heaters 17 are evenly arranged around its perimeter. The internal auxiliary heaters 17 use resistance heating, which can heat the internal temperature of the cavity to 200-400℃, and the process temperature is maintained stable through the insulation layer. A carrier plate 2 is horizontally arranged at the bottom of the cavity 1. The carrier plate 2 can be made of graphite or aluminum alloy, and its surface is anodized. It is used to support the silicon wafers 3 to be processed.

[0032] The gas equalization assembly is installed on top of cavity 1. Isolation plate A16 is bolted to the top flange of cavity 1. Isolation plate A16 is made of quartz, and both its upper and lower surfaces have sealing grooves with fluororubber sealing rings installed inside to achieve a vacuum seal between the cavity and the outside. Upper electrode plate 9 is made of aluminum alloy and is bolted to the upper surface of isolation plate A16. Gas inlet assembly 8 is installed at the top center of upper electrode plate 9 and communicates with the gas chamber inside upper electrode plate 9.

[0033] The gas equalization layer frame 5 is made of aluminum alloy and is fixed to the lower surface of the upper electrode plate 9 with bolts. The gas equalization plate B7, gas equalization plate A6, and gas equalization isolation plate 4 are fixed in parallel from top to bottom inside the gas equalization layer frame 5, with a certain gas diffusion space between them. Gas equalization holes 22 are opened on the gas equalization plate B7, gas equalization plate A6, and gas equalization isolation plate 4. The gas equalization holes 22 are arranged in an exponential level of two-to-four and four-to-sixteen. In this embodiment, according to the specifications of the cavity diameter of 600mm and the ability to support 12 6-inch silicon wafers, a total of 256 gas equalization holes with a diameter of 1.5mm are opened on the gas equalization isolation plate 4 to ensure that the process gas can be uniformly diffused to the entire cross-section of the cavity.

[0034] The cross electrode assembly is mounted on the lower surface of the gas equalization isolation plate 4. 32 positive electrode posts 10 and 32 negative electrode posts 11, made of stainless steel with a diameter of 3mm, are arranged alternately at equal intervals and fixed to the gas equalization isolation plate 4 by threads. The gas equalization isolation plate 4 is made of quartz material with a thickness of 10mm to ensure insulation between the positive and negative electrode posts. The upper ends of all the positive electrode posts 10 converge at the left side of the gas equalization isolation plate 4 and are welded to a copper electrode connecting post 12; the upper ends of all the negative electrode posts 11 converge at the right side of the gas equalization isolation plate 4 and are welded to another copper electrode connecting post 12.

[0035] The upper ends of the two electrode connecting posts 12 are vertically welded to the lower ends of one electrode lead-out post 13. The electrode lead-out post 13 is made of copper, has a diameter of 8mm, and extends into the cavity from the top of the upper electrode plate 9. A quartz electrode lead-out isolation sleeve 21 is fitted over the part of the electrode lead-out post 13 that passes through the gas equalization layer frame 5 to prevent short circuits between the electrode lead-out post 13 and the aluminum alloy gas equalization layer frame 5. A lower isolation sleeve 14 is provided on the upper surface of the gas equalization layer frame 5 corresponding to the position of the electrode lead-out post 13. An upper isolation sleeve 19 is nested within the part of the electrode lead-out post 13 that extends out of the upper electrode plate 9. Both the lower isolation sleeve 14 and the upper isolation sleeve 19 are made of polytetrafluoroethylene, and fluororubber sealing rings 20 are provided at both ends to achieve vacuum sealing. Finally, the upper isolation sleeve 19, the lower isolation sleeve 14, and the entire set of electrode posts are pressed and fixed onto the upper electrode plate 9 by a stainless steel pressure plate 18 and bolts.

[0036] Quartz isolation plates B15 are fixed around the lower surface of the upper electrode plate 9. The isolation plates B15 are 50mm high and are used to limit the plasma generation area to the central area below the electrode, prevent the plasma from spreading at the edge of the cavity, and further improve the uniformity of plasma distribution.

[0037] The specific working process is as follows: First, the silicon wafer 3 to be processed is placed on the carrier plate 2, the cavity door is closed, and a vacuum is drawn to the required background vacuum level. The internal auxiliary heater 17 is turned on to heat the inside of the cavity to the set process temperature. Process gases (such as silane, ammonia, hydrogen, etc.) enter the internal cavity of the upper electrode plate 9 from the gas inlet assembly 8, and then flow through the gas equalization plate B7 and the gas equalization plate A6 in sequence for preliminary gas equalization. Finally, the gases are evenly diffused into the reaction area inside the cavity through the gas equalization holes 22 on the gas equalization isolation plate 4.

[0038] When the radio frequency power supply is turned on, power is transmitted through electrode lead-out post 13 and electrode connection post 12 to positive electrode post 10 and negative electrode post 11, forming a multi-dimensional interwoven electric field between the cross-arranged positive and negative electrode posts. The electric field excites the process gas to generate plasma, and electrons move in three dimensions in the complex electric field, colliding frequently with gas molecules to achieve efficient ionization. Since the plasma generation area is spatially decoupled from the silicon wafer 3 placement area, the silicon wafer 3 does not participate in the discharge process, avoiding direct bombardment by high-energy particles.

[0039] To adjust the ion energy acting on the surface of silicon wafer 3, the independent bias power supply on one side of carrier plate 2 can be turned on. By applying different bias voltages, the bombardment energy of the ions can be controlled to meet the needs of different thin film deposition processes. After the process is completed, the power supply and gas supply are turned off, and after the chamber cools down, it is filled with atmosphere, and then the silicon wafer can be removed.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A large-area uniform gas cross-electrode plasma ionization device, characterized in that, Includes cavity (1), carrier plate (2), gas equalization assembly and cross electrode assembly; The carrier plate (2) is disposed inside the cavity (1) at the bottom and supports the substrate to be processed; The gas equalization assembly is disposed above the cavity (1) and includes an air inlet assembly (8), an upper electrode plate (9), a gas equalization plate A (6), a gas equalization plate B (7), a gas equalization isolation plate (4), and a gas equalization layering frame (5). The air inlet assembly (8) is disposed above the upper electrode plate (9) to introduce process gas. After entering from the air inlet assembly (8), the process gas flows sequentially through the upper electrode plate (9), the gas equalization plate B (7), the gas equalization plate A (6), and the gas equalization isolation plate (4). The gas equalization isolation plate (4), the gas equalization plate A (6), and the gas equalization plate B (7) are all fixed to the gas equalization layering frame (5), and the gas equalization layering frame (5) is fixed to the upper electrode plate (9). The cross electrode assembly includes a positive electrode post (10), a negative electrode post (11), an electrode connecting post (12), and an electrode lead-out post (13). The positive electrode post (10) and the negative electrode post (11) are arranged alternately and fixed on the gas-equalizing isolation plate (4). The positive electrode post (10) is gathered on one side and connected to an electrode connecting post (12), and the negative electrode post (11) is gathered on the other side and connected to another electrode connecting post (12). The electrode connecting post (12) is connected to one end of the electrode lead-out post (13), and the other end of the electrode lead-out post (13) extends to the outside of the cavity (1) and is connected to the power supply.

2. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, The cavity (1) is provided with an internal auxiliary heat source (17) around its inner wall to provide and maintain the process temperature.

3. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, The gas-equalizing isolation plate (4) is made of insulating material and electrically isolates the positive electrode post (10) from the negative electrode post (11).

4. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, The electrode lead-out column (13) extends from above the upper electrode plate (9) and is vertically connected to the electrode connecting column (12); the part of the electrode lead-out column (13) that passes through the gas equalization layer frame (5) is fitted with an electrode lead-out isolation sleeve (21), a lower isolation sleeve (14) is provided above the gas equalization layer frame (5), an upper isolation sleeve (19) is nested at the outer end of the electrode lead-out column (13), and sealing rings (20) are provided on both sides of the lower isolation sleeve (14) and the upper isolation sleeve (19). The entire set of electrode columns is fixed to the upper electrode plate (9) by the pressure plate (18).

5. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, An isolation plate A (16) is fixed on the cavity (1), and an upper electrode plate (9) is fixed on the isolation plate A (16). Sealing rings are provided on both the upper and lower surfaces of the isolation plate A (16). An isolation plate B (15) is provided around the lower part of the upper electrode plate (9) to limit the plasma generation area in the cavity (1).

6. The large-area uniform gas cross-electrode plasma ionization device according to any one of claims 3-5, characterized in that, The gas-uniform isolation plate (4), lower isolation sleeve (14), isolation plate B (15), isolation plate A (16), upper isolation sleeve (19), and electrode lead-out isolation sleeve (21) are made of any one of quartz, ceramic, or PEEK insulating material.

7. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, The gas equalization plate A (6), gas equalization plate B (7) and gas equalization isolation plate (4) are all provided with gas equalization holes (22), and the gas equalization holes (22) are arranged in an exponential manner according to the cavity size and the arrangement of the substrate to be treated.

8. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, The substrate to be processed is any one of silicon wafer (3), irregular structural parts, large-size substrate, insulating material substrate or organic sensitive material substrate.

9. The large-area uniform gas cross-electrode plasma ionization device according to claim 1, characterized in that, An independent electric field control unit is also provided on the side of the carrier plate (2) or the side of the substrate to be treated to regulate the energy of the ionized ions.

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