Gas inlet and radio frequency system of plate-type PECVD equipment

Abstract

The invention relates to the field of photovoltaic equipment, and discloses a plate-type PECVD (Plasma Enhanced Chemical Vapor Deposition) equipment air inlet and radio frequency system which is arranged on a cavity cover of equipment. The device comprises nine special gas inlets, four remote plasma source gas inlets, a radio frequency power supply feed-in system cooperating with the special gas inlets in quantity and space distribution, and a multi-stage split-flow gas pipeline system with active adjustment capability. The nine special gas inlets form a uniform gas atmosphere of'peripheral symmetrical surrounding + center vertical injection ', and each special gas inlet is correspondingly provided with a radio frequency power supply feed-in point. The four remote plasma source air inlets are symmetrically distributed along the center line of the air distribution box and located in the four evenly-divided areas. According to the multi-stage split-flow gas pipeline system, a main pipeline is communicated with each gas inlet and each cleaning port through a plurality of split-flow branches, metering valves are arranged on the plurality of split-flow branches, and the flow of each split-flow branch is controlled through a flow controller. Therefore, the uniformity of the special gas and the cleaning effect of the RPS are improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic equipment, and in particular to an air intake and radio frequency system for a plate-type PECVD equipment. Background Technology

[0002] In the coating process of photovoltaic cells, plate-type PECVD equipment is widely used for thin film preparation. The uniformity of the film layer is directly related to the photoelectric conversion efficiency, color consistency, and yield of the cell. This uniformity is mainly determined by two core factors: the spatial distribution uniformity of the reactant gases and the density uniformity of the plasma glow discharge. Meanwhile, the cleanliness and maintenance of the reaction chamber are also key factors affecting the coating quality and stable operation of the equipment.

[0003] Current plate-type PECVD equipment typically employs five reactive gas inlets, five corresponding RF power supply feed points, and two remote plasma inlets within its process chamber. The five reactive gas inlets are located at the center point and four corners of the chamber cover, while the two remote plasma inlets are positioned on either side of the center point. The reactive gas is introduced via a main special gas inlet pipe, which then branches into five sub-pipes connected to the five reactive gas inlets. The remote plasma cleaning gas is introduced via a main cleaning gas inlet pipe, which then branches into two sub-pipes connected to the two remote plasma inlets.

[0004] This existing approach has inherent drawbacks: First, due to the limited number and layout of gas inlets, and the inability to control the airflow at each inlet, the reactant gas or cleaning agent cannot achieve large-area, highly uniform diffusion after entering the spacious chamber, resulting in a concentration gradient within the chamber. Second, the corresponding number of RF feed points is too small, making it difficult to generate a uniform plasma field within a large chamber. Third, the traditional distribution of two remote plasma inlets creates dead zones in the radiation area and gas inhomogeneity, leading to uneven cleaning, low efficiency, and the presence of cleaning dead zones. The combined effect of gas and plasma inhomogeneities amplifies the non-uniformity of thin film deposition, causing fluctuations in thickness and refractive index. Although limited compensation can be achieved by adjusting process parameters, the adjustment capability has reached a bottleneck and cannot meet the stringent requirements for film uniformity in next-generation high-efficiency batteries. Summary of the Invention

[0005] The purpose of this invention is to provide an air intake and radio frequency system for plate-type PECVD equipment, which solves the problems of uneven gas distribution, incomplete cavity cleaning, and uneven plasma field in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention discloses a plate-type PECVD equipment air intake and radio frequency system, which is installed on the cavity cover of the equipment. It includes nine special gas inlets, four remote plasma source inlets, a radio frequency power supply feeding system that coordinates with the special gas inlets in terms of quantity and spatial distribution, and a multi-stage split gas pipeline system with active adjustment capability.

[0008] The gas distribution box is divided into nine regions in a nine-square grid pattern, and the nine special gas inlets are located in the nine regions respectively; each special gas inlet is equipped with a corresponding radio frequency power input point; each radio frequency power input point is independently excitation controlled.

[0009] The gas distribution box is divided into four equal regions along a cross shape, and the four remote plasma source inlets are located in the four regions respectively.

[0010] Nine of the special gas inlets are symmetrically distributed along the center line of the gas distribution box, and four remote plasma source inlets are symmetrically distributed along the center line of the gas distribution box.

[0011] The multi-stage gas distribution pipeline system includes: a flow controller, a metering valve, a special gas main pipeline, a remote plasma main pipeline, and several special gas distribution branches and remote plasma distribution branches. The special gas distribution branches are connected to the special gas main pipeline and are used to uniformly and controllably distribute the gas from the special gas main pipeline to nine special gas inlets. The remote plasma distribution branches are connected to the remote plasma main pipeline and are used to uniformly and controllably distribute the gas from the remote plasma main pipeline to four remote plasma source inlets. The metering valve is installed on several special gas distribution branches and remote plasma distribution branches. The flow controller is electrically connected to the metering valve and is used to control the flow rate adjustment of each branch.

[0012] Furthermore, the nine special gas inlets are located at the center of the nine regions, and the four remote plasma source inlets are located at the center of the four regions.

[0013] Furthermore, the nine special gas inlets are respectively one central special gas inlet, four corner special gas inlets, and four intermediate special gas inlets. The central special gas inlet is located at the center of the gas distribution box, the corner special gas inlets are located at the four corners of the gas distribution box, and the intermediate special gas inlets are located between two adjacent corner special gas inlets.

[0014] The special gas diversion branch includes a first-level diversion branch, a second-level diversion branch, a third-level diversion branch, and four first-level and four second-level diversion branches.

[0015] The metering valve is installed on the first secondary diversion branch, the second secondary diversion branch, and the third secondary diversion branch.

[0016] One end of the first and third-level diversion branch is connected to the corner special gas inlet, and the other end is connected to the first and second-level diversion branch.

[0017] One end of the second and third level diversion branch is connected to the intermediate special gas inlet, and the other end is connected to the second and second level diversion branch.

[0018] The third and second-level diversion branch is connected to the central special gas inlet.

[0019] The four first and third-level diversion branches and the four second and third-level diversion branches have the same length and diameter.

[0020] Furthermore, the remote plasma shunt branch is provided with four branches, which are respectively connected to the four remote plasma source inlets, and each remote plasma shunt branch is provided with a metering valve.

[0021] The advantages of this invention are:

[0022] 1. This invention balances the uniformity of the special gas and the cleaning effect of RPS while also considering cost savings. Through extensive experimental research and comparison, the critical point between the number of air inlets and cleaning ports was identified. By optimizing the placement and piping design, the invention achieves maximum gas uniformity with a limited number of air inlets. By simultaneously increasing and optimizing the special gas introduction path and RF feed point layout, and introducing active, zone-controllable flow regulation capabilities, the invention achieves dual and adjustable uniform distribution of gas and electricity at both the physical structure and dynamic control levels. This fundamentally improves the uniformity, process adaptability, and controllability of thin film deposition, thereby significantly enhancing the coating quality.

[0023] 2. This invention employs four sets of remote plasma sources, symmetrically distributed around the cavity, to achieve efficient and uniform coverage of the cavity interior. Each remote plasma source is equipped with an independent gas path and excitation device, allowing for independent adjustment of plasma power and gas flow rate according to process requirements, thus enhancing the flexibility and adaptability of the cleaning process.

[0024] 4. The gas pipeline lengths of the same-level branches of the present invention are designed to be equal, which can further ensure the consistency of the outlet flow rate. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1.

[0027] Figure 2 It is a distribution diagram of nine special gas inlets and a multi-stage gas distribution pipeline system.

[0028] Figure 3 yes Figure 2 A magnified view of a multi-stage gas splitting pipeline.

[0029] Figure 4 This is a distribution diagram of the four remote plasma source inlets.

[0030] Figure 5 This is a simplified distribution diagram of the special gas inlet and the remote plasma source inlet in Comparative Example 1.

[0031] Figure 6 This is a simplified distribution diagram of the special gas inlet and the remote plasma source inlet in Comparative Example 3.

[0032] Explanation of key component symbols:

[0033] 1. Central special gas inlet; 2. Corner special gas inlet; 3. Intermediate special gas inlet; 4. Remote plasma source inlet; 5. Metering valve; 6. Main special gas pipeline; 7. Cavity cover; 8. First and second-level branch lines; 9. Second and second-level branch lines; 10. Third and second-level branch lines; 11. First and third-level branch lines; 12. Second and third-level branch lines; 13. Remote plasma branch line; 14. Radio frequency power supply feed system. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In this invention, unless otherwise stated, directional terms such as "up," "down," "left," and "right" are generally understood in conjunction with the accompanying drawings and the directions shown in actual applications.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "discretionary" mean that they may or may not be included (or may or may not be present).

[0039] Example 1:

[0040] like Figures 1 to 4 As shown, the present invention discloses an air intake and radio frequency system for a plate-type PECVD equipment, which is installed on the cavity cover 7 of the equipment. It includes nine special gas inlets, four remote plasma source inlets 4, and a radio frequency power supply feed system 14 that coordinates with the special gas inlets in terms of quantity and spatial distribution, as well as a multi-stage split gas pipeline system with active adjustment capability.

[0041] The gas distribution box is divided into nine regions in a 3x3 grid pattern, with nine special gas inlets located at the center of each region. Each special gas inlet corresponds to a radio frequency (RF) power input point. Each RF power input point is independently controlled. The gas inlets and RF power input points are treated as a coordinated system for synchronous expansion and optimization, achieving a configuration upgrade from "5+5" to "9+9," and introducing independent flow rate adjustment capabilities for each zone after gas path and diversion. This physically enhances process uniformity. Specifically, in this embodiment, the nine special gas inlets are a central special gas inlet 1, four corner special gas inlets 2, and four intermediate special gas inlets 3. The central special gas inlet 1 is located at the center of the gas distribution box, the corner special gas inlets 2 are located at the four corners of the gas distribution box, and the intermediate special gas inlets 3 are located between adjacent corner special gas inlets 2. Both gas introduction and RF power input include independent points at the center, effectively solving the "gas and plasma starvation effect" at the center of the chamber in traditional solutions, ensuring the synchronicity and uniformity of the reaction throughout the entire chamber region.

[0042] The gas distribution box is divided into four equal regions in a cross shape. Four remote plasma source inlets are located at the center of each of the four regions. Plasma gas radiates outwards in a circular pattern from the four remote plasma source inlets, completely covering the entire cavity and improving its cleaning effect.

[0043] The multi-stage gas splitting pipeline system includes: a flow controller, a metering valve 5, a special gas main pipeline 6, a remote plasma main pipeline, and several special gas splitting branches and remote plasma splitting branches 13.

[0044] The special gas diversion branch is connected to the special gas main pipeline 6, and is used to uniformly and controllably divert the gas from the special gas main pipeline 6 to nine special gas inlets. The remote plasma diversion branch 13 is connected to the remote plasma main pipeline, and is used to uniformly and controllably divert the gas from the remote plasma main pipeline to four remote plasma source inlets 4. Specifically, the special gas diversion branch in this embodiment includes a first secondary diversion branch 8, a second secondary diversion branch 9, a third secondary diversion branch 10, and four first tertiary diversion branches 11 and four second tertiary diversion branches 12. Metering valves 5 are installed on the first secondary diversion branches 8, 9, and 10. One end of the first tertiary diversion branch 11 is connected to the corner special gas inlet, and the other end is connected to the first secondary diversion branch 8. One end of the second tertiary diversion branch 12 is connected to the middle special gas inlet, and the other end is connected to the second secondary diversion branch 9. The third and second-level diversion branches 10 are connected to the central special gas inlet. The four first and third-level diversion branches 11 and the four second and third-level diversion branches 12 have the same length and diameter. There are four remote plasma diversion branches 13, which are connected to the four remote plasma source inlets 4 respectively. Each remote plasma diversion branch 13 is equipped with a metering valve 5.

[0045] The flow controller is electrically connected to the metering valve 5 and is used to control the flow regulation of each branch.

[0046] Comparative Example 1:

[0047] like Figure 5 As shown, this comparative example adopts the existing 5+2 air intake distribution layout, that is: the gas distribution box is divided into four equal regions along a cross shape, with four special gas inlets located at the center of each of the four regions, and one more special gas inlet located at the center of the gas distribution box. The gas distribution box is further divided into two equal regions, with two remote plasma source inlets 4 located at the center of each of the two regions.

[0048] Other technical features are consistent with those in Example 1.

[0049] Comparative Example 2: This comparative example adopts the same 9+4 air intake distribution layout as Example 1, that is, the gas distribution box is divided into nine regions in a nine-square grid pattern, and the nine special gas inlets are located at the center of each of the nine regions. The gas distribution box is divided into four regions in a cross shape. The four remote plasma source inlets 4 are located at the center of each of the four regions. However, the multi-stage split gas pipeline system adopts the existing unregulated mode, that is, the gas enters from the main pipeline and is randomly distributed to the branches connected to it.

[0050] Other technical features are consistent with those in Example 1.

[0051] Comparative Example 3:

[0052] like Figure 6 As shown, this comparative example employs a 12+6 air intake distribution layout, meaning the gas distribution box is divided into 12 regions in a 3x4 grid, with each of the 12 special gas intakes located at the center of one of the 12 regions. The gas distribution box is further divided into 6 regions in a 3x2 grid, with each of the 6 remote plasma source intakes located at the center of one of the 6 regions.

[0053] Other technical features are consistent with those in Example 1.

[0054] Experimental data:

[0055] Increasing the number of air inlets theoretically improves the uniformity of gas distribution, but it also increases the difficulty and cost of equipment manufacturing. Therefore, this solution balances the uniformity of the special gas and the cleaning effect of RPS while also considering cost savings. Through strategic layout and piping design, it achieves maximum cost-effectiveness in terms of gas uniformity and cleaning effect with a limited number of air inlets and cleaning ports. The following compares the uniformity of the special gas and the cleaning effect of RPS in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3:

[0056] The silicon wafer coating uniformity test involves coating silicon wafers on a carrier plate using the schemes of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example 1. The film thickness of the silicon wafers in each area of ​​the carrier plate is measured multiple times for each scheme, and the average value is taken to calculate the film thickness non-uniformity ratio corresponding to each scheme.

[0057] In the PECVD coating cleaning process, the cleaning effect of RPS can be quantitatively analyzed by the median of the difference in silicon wafer cleanliness. From both statistical and process characterization perspectives, the median, as a key indicator reflecting the central tendency of data, can effectively avoid the interference of extreme values ​​and accurately reflect the overall distribution characteristics of silicon wafer surface cleanliness. The higher the median, the better the uniformity of surface cleanliness and the overall cleaning effect of the silicon wafer under the RPS cleaning process. This data evaluation of the cleaning effect of RPS in the PECVD process uses the following method: the carrier board covered with bare silicon wafers is weighed before and after cleaning. By calculating the weight difference of each silicon wafer and analyzing the median of this data, the cleaning effect of RPS on the silicon wafers can be determined, and thus the overall cleanliness inside the chamber can be inferred.

[0058] As shown in Tables 1, 2, and 9, Comparative Example 1, which uses a configuration with 5 air inlets and 2 cleaning ports and a multi-stage split gas pipeline system with active adjustment capability, has a non-uniformity rate of 22.60% and a median difference in the bare die value of 0.55.

[0059] As shown in Tables 3, 4 and 9, Example 1 uses a method with 9 air inlets and 4 cleaning ports, as well as a multi-stage split gas pipeline system with active adjustment capability. Its non-uniformity ratio is 10.60%, and the median difference of the bare die is 1.35.

[0060] As shown in Tables 5, 6, and 9, Comparative Example 2, which uses a configuration of 9 air inlets and 4 cleaning ports, along with the existing non-adjustable multi-stage split gas pipeline system, has a non-uniformity ratio of 16.91% and a median difference in bare wafer values ​​of 0.76.

[0061] As shown in Tables 7, 8, and 9, Comparative Example 3, which uses a configuration of 12 air inlets and 6 cleaning ports, along with a multi-stage split gas pipeline system with active adjustment capabilities, has a non-uniformity rate of 9.80% and a median difference in the bare die values ​​of 1.39.

[0062] A comparison of the data from Example 1 and Comparative Example 2 shows that the multi-stage gas pipeline system of this embodiment significantly improves the coating uniformity (reduced from 22.60% to 10.60%) and cleaning effect (increased from 0.55 to 1.35).

[0063] A comparison of the data from Comparative Example 1, Example 1, and Comparative Example 3 shows that increasing the number of air inlets and cleaning ports can reduce coating unevenness and improve cleaning performance. However, comparing the magnitude of improvement, Example 1, with its four additional air inlets and two additional cleaning ports compared to Comparative Example 1, achieves a doubling of improvement in coating uniformity and cleaning performance, while still meeting the current requirements for film uniformity in high-efficiency batteries. Comparative Example 3, also with four additional air inlets and two additional cleaning ports compared to Example 1, only shows a slight improvement in coating uniformity and cleaning performance. Considering the cost-benefit ratio, the number and layout of air inlets and cleaning ports used in this example not only significantly improve coating uniformity and cleaning performance, meeting the current requirements for film uniformity in high-efficiency batteries, but also controls the increase in manufacturing costs.

[0064]

[0065] Table 1. Test data on silicon wafer coating uniformity under Comparative Example 1.

[0066]

[0067] Table 2. Simulated RPS cleaning data under the scheme of Comparative Example 1

[0068]

[0069] Table 3. Test data on silicon wafer coating uniformity under the scheme of Example 1.

[0070]

[0071] Table 4. Simulated RPS cleaning data under the scheme of Example 1

[0072]

[0073] Table 5. Test data on silicon wafer coating uniformity under Comparative Example 2.

[0074]

[0075] Table 6. Simulated RPS cleaning data under Comparative Example 2

[0076]

[0077] Table 7 Test data on silicon wafer coating uniformity under Comparative Example 3

[0078]

[0079] Table 8. Simulated RPS cleaning data under Comparative Example 3.

[0080] Table 9 Comparison of parameters between Comparative Examples 1 to 3 and Example 1

[0081] In summary, this invention can improve the uniformity of special gases and the cleaning effect of RPS under controllable manufacturing costs, thus meeting the current requirements of high-efficiency batteries for film uniformity.

[0082] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A plate-type PECVD equipment air intake and radio frequency system, disposed on the cavity cover (7) of the equipment, characterized in that: It includes nine special gas inlets, four remote plasma source inlets (4), and a radio frequency power supply feed system (14) that coordinates with the special gas inlets in terms of quantity and spatial distribution, as well as a multi-stage split gas pipeline system with active adjustment capability; The gas distribution box is divided into nine regions in a nine-square grid pattern. The nine special gas inlets are located in the nine regions and correspond one-to-one. Each special gas inlet is equipped with a corresponding radio frequency power input point. Each radio frequency power input point is independently excitation controlled. The gas distribution box is divided into four regions in a cross shape. The four remote plasma source inlets (4) are located in the four regions respectively and correspond one to one. Nine of the special gas inlets are symmetrically distributed along the center line of the gas distribution box, and four remote plasma source inlets (4) are symmetrically distributed along the center line of the gas distribution box. The multi-stage gas distribution pipeline system includes: a flow controller, a metering valve (5), a special gas main pipeline (6), a remote plasma main pipeline, and several special gas distribution branches and remote plasma distribution branches (13); the special gas distribution branches are connected to the special gas main pipeline (6) and are used to uniformly and controllably distribute the gas in the special gas main pipeline (6) to nine special gas inlets; the remote plasma distribution branches (13) are connected to the remote plasma main pipeline and are used to uniformly and controllably distribute the gas in the remote plasma main pipeline to four remote plasma source inlets (4); the metering valve (5) is installed on several special gas distribution branches and remote plasma distribution branches (13); The flow controller is electrically connected to the metering valve (5) and is used to control the flow regulation of each branch.

2. The air intake and radio frequency system for plate-type PECVD equipment according to claim 1, characterized in that: The nine special gas inlets are located at the center of the nine regions, and the four remote plasma source inlets (4) are located at the center of the four regions.

3. The air intake and radio frequency system for plate-type PECVD equipment according to claim 2, characterized in that: The nine special gas inlets are respectively a central special gas inlet (1), four corner special gas inlets (2), and four intermediate special gas inlets (3); the central special gas inlet (1) is located in the center of the gas distribution box, the corner special gas inlets (2) are located at the four corners of the gas distribution box, and the intermediate special gas inlets (3) are located between two adjacent corner special gas inlets (2); The special gas diversion branch includes a first and second level diversion branch (8), a second and second level diversion branch (9), a third and second level diversion branch (10), and four first and third level diversion branches (11) and four second and third level diversion branches (12). The metering valve (5) is installed on the first secondary diversion branch (8), the second secondary diversion branch (9), and the third secondary diversion branch (10); One end of the first third-level diversion branch (11) is connected to the corner special gas inlet, and the other end is connected to the first second-level diversion branch (8); One end of the second and third level diversion branch (12) is connected to the intermediate special gas inlet, and the other end is connected to the second and second level diversion branch (9); The third secondary diversion branch (10) is connected to the central special gas inlet; The four first and third-level diversion branches (11) have the same length and diameter, and the four second and third-level diversion branches (12) have the same length and diameter.

4. The air intake and radio frequency system for plate-type PECVD equipment according to claim 2, characterized in that: The remote plasma diversion branch (13) is provided with four branches, which are respectively connected to the four remote plasma source inlets (4). Each remote plasma diversion branch (13) is provided with a metering valve (5).

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