PECVD with auxiliary heating device and heating control method
By setting up multiple auxiliary heating plates around the furnace body of the PECVD equipment and independently controlling their power, the problems of pollution and short lifespan of auxiliary heating devices are solved, resulting in more uniform coating and higher equipment capacity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUNAN RED SUN PHOTOELECTRICITY SCI & TECH
- Filing Date
- 2022-08-29
- Publication Date
- 2026-05-19
AI Technical Summary
The auxiliary heating devices in existing PECVD equipment are prone to contaminating the coating process, have a short lifespan, occupy reaction chamber space, and affect equipment capacity and maintenance costs.
Multiple auxiliary heating plates are integrated into the periphery of the furnace body. Using auxiliary heating devices made of the same material as the main heating components, the auxiliary heating plates are located above and below the graphite boat. Uniform heating is achieved by independently controlling the power of the heating plates.
It improves coating uniformity and temperature control accuracy, extends equipment life, reduces maintenance frequency and cost, and increases equipment capacity.
Smart Images
Figure CN117660937B_ABST
Abstract
Description
Technical Field
[0001] This invention mainly relates to the field of photovoltaic cell manufacturing technology, specifically a PECVD with auxiliary heating device and a heating control method. Background Technology
[0002] Silicon wafers undergo texturing, diffusion, etching, annealing, surface coating, passivation, screen printing, and sintering to become solar cells. The specific processes vary depending on the individual wafers. Surface coating is one of the core processes in photovoltaic cell production, and PECVD (Precision Continuous Chemical Deposition) is the equipment used for surface coating. PECVD equipment consists of three main parts: the furnace cabinet, the clean bench, and the source cabinet. The reaction chamber, located inside the furnace cabinet, is where the coating reaction takes place, typically at 400℃-600℃. Existing tubular PECVD furnaces have a cylindrical structure with heating wires wrapped around the outer wall of a quartz tube. The quartz tube forms a coating reaction chamber, which is heated by a cylindrical heating cavity. A graphite boat is located inside the reaction chamber. Due to its vertical insert structure, the outer blades of the graphite boat have a large heating area and are easily heated by the furnace. However, the blades and silicon wafers in the middle of the graphite boat are farther from the heating element, and the middle blades receive less radiation from the heating element, making them more difficult to heat. Current solutions typically involve extending the isothermal time to achieve uniform heating of the middle blades, but extending the heating time significantly reduces the equipment's coating capacity.
[0003] To reduce process time and improve coating uniformity, existing technologies typically add auxiliary heating devices to the reaction chamber to provide separate auxiliary heating to the top and bottom of the graphite boat. This results in better temperature uniformity within the graphite boat and the silicon wafers inside, meeting process temperature requirements. The auxiliary heating devices can shorten process time, thereby increasing equipment capacity and performance. For example, patent 201920037274.6 discloses installing multiple auxiliary heating devices and heating sleeves inside the reaction chamber of the main heating furnace to assist in heating the main furnace during the heating phase, shortening heating and process time. Patent 201920978650.1 discloses using a tungsten filament infrared auxiliary heater placed between the quartz tube in the reaction chamber and the bottom of the graphite boat to generate infrared light for auxiliary heating, achieving comprehensive heating of the silicon wafers, shortening process time, and reducing coating color difference. Patent 202023146457.3 discloses using a resistance heating rod combined with a quartz sleeve to achieve auxiliary heating within the PECVD reaction chamber. This method simplifies the auxiliary heating device within the chamber and facilitates its application in PECVD.
[0004] However, the auxiliary heating devices used in existing equipment generally contain metals such as magnesium or tungsten, which can easily contaminate the coating process and reduce the efficiency of the solar cells. They are generally protected by quartz sleeves. In the reaction chamber, the auxiliary heating and its protective quartz sleeve occupy part of the space inside the quartz tube, affecting the entry and exit of the graphite boat and the movement of the boat. The boat carrier is prone to colliding with the auxiliary heating device when entering and exiting the graphite boat, which can easily lead to damage to the auxiliary heating device and its quartz sleeve. Furthermore, the heating rod and the adaptation sleeve may be damaged for various reasons. The infrared heating rod usually has a lifespan of only 6 to 10 months. In addition, the heating rod is relatively heavy and is prone to damaging the quartz sleeve when it is positioned at the top for auxiliary heating. The space inside the reaction chamber is relatively small. To provide auxiliary heating to the graphite boat in a small space, a relatively large power of the auxiliary heating device is usually used, which results in a high heating surface load of the auxiliary heating device, reducing the lifespan of the auxiliary heating device itself and increasing the probability of damage.
[0005] Due to the coating deposition in the reaction chamber, the quartz sleeve usually requires regular cleaning and maintenance. When the auxiliary heating device or its sleeve is damaged and needs to be replaced, the reaction chamber must be cooled down to a temperature that is safe for human operation, which significantly affects the equipment's operating time, reduces its production capacity, and increases maintenance costs. Furthermore, frequent cooling also has a significant impact on the service life of components such as the quartz tube, furnace body, and sealing rings. Summary of the Invention
[0006] To address the technical problems existing in the prior art, this invention provides a PECVD and heating control method with an auxiliary heating device that offers better heating uniformity, higher temperature control accuracy, more convenient installation and maintenance, more flexible heating plate arrangement, and can effectively improve coating uniformity.
[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0008] A PECVD with an auxiliary heating device includes a furnace body, which includes a furnace shell and an insulation layer, a main heating component, and a quartz tube disposed within the furnace shell. The main heating component is wound around the outer wall of the quartz tube. The furnace body also includes an auxiliary heating component, which includes at least two auxiliary heating plates, which are respectively arranged above and below the main heating component.
[0009] As a further improvement of the present invention, it also includes an auxiliary heating power regulator, which is used to control the output of different power from multiple auxiliary heating plates.
[0010] As a further improvement of the present invention: the auxiliary heating power regulator includes a first auxiliary heating power regulator and a second auxiliary heating power regulator, the first auxiliary heating power regulator and the second auxiliary heating power regulator are respectively used to control the power output of the upper auxiliary heating plate and the lower auxiliary heating plate.
[0011] As a further improvement of the present invention: the auxiliary heating plate includes heating wires and a fixing plate, wherein the fixing plate is used to fix the heating wires.
[0012] As a further improvement of the present invention: the fixing plate has a first groove for fixing the heating wire.
[0013] As a further improvement of the present invention: the first groove is a trapezoidal groove or a circular groove with an opening.
[0014] As a further improvement of the present invention: the heating wires are arranged in a spiral or serpentine pattern on the fixed plate.
[0015] As a further improvement of the present invention: the fixing plate is provided with an insulator fixing groove for fixing the auxiliary heating plate to the outside of the insulator string of the main heating assembly.
[0016] As a further improvement of the present invention: the main heating assembly includes multiple sets of main heating coils and a main heating regulator, which is used to connect to the multiple sets of main heating coils and to control the heating of the multiple sets of main heating coils.
[0017] As a further improvement of the present invention: the total length of the multiple auxiliary heating plates is not less than the total length of the graphite boat.
[0018] This invention also discloses a heating control method for PECVD with an auxiliary heating device as described above, the steps of which include:
[0019] Step S1: Set the target temperature required for the reaction chamber and start the main heating component;
[0020] Step S2: Turn on the auxiliary heating component;
[0021] Step S3: Adjust the power of different auxiliary heating plates in the auxiliary heating assembly at different stages of the coating process;
[0022] Step S4: After the coating process is completed, turn off the auxiliary heating components.
[0023] As a further improvement of the present invention, step S3 specifically includes:
[0024] Step S301: During the heating stage of the PECVD reaction chamber, the auxiliary heating components are at full power output;
[0025] Step S302: During the constant temperature stage of the process, adjust the output power of each auxiliary heating plate in the auxiliary heating assembly so that the output power of the upper auxiliary heating plate is less than the output power of the lower auxiliary heating plate.
[0026] Step S303: During the process deposition stage, reduce the output power of each auxiliary heating plate in the auxiliary heating assembly.
[0027] Compared with the prior art, the advantages of the present invention are as follows:
[0028] 1. The PECVD with auxiliary heating device of the present invention integrates the auxiliary heating plate into the furnace body. Multiple auxiliary heating plates are arranged around the main heating component of the furnace body, and multiple sets of auxiliary heating wires are embedded in the auxiliary heating plates to provide auxiliary heating to the graphite boat inside the furnace body. The auxiliary heating plate uses the same material as the heating wires of the main heating component of the furnace body, has the same lifespan as the furnace body, is not located in the reaction chamber, and requires no maintenance during use. Because this auxiliary heating component is located outside the reaction chamber, it will not cause contamination of the reaction chamber due to damage to the quartz sleeve, unlike auxiliary heating devices inside the reaction chamber, thus avoiding contamination caused by auxiliary heating. Downtime maintenance due to equipment failure can effectively improve equipment productivity; the auxiliary heating device is located outside the reaction chamber, without occupying space inside the reaction chamber, facilitating the entry and exit of the graphite boat; the auxiliary heating plate is located outside the furnace wire, using multiple sets of auxiliary heating wires for auxiliary heating, with the heating plate located above and below the graphite boat, both using a plate-type heating method, which provides more uniform heating compared to the heating rod structure; the auxiliary heating plate can be designed as multiple heating plates according to the heating needs of the graphite boat, enabling multi-stage auxiliary heating of the graphite boat, which is more conducive to the temperature control accuracy of the graphite boat and effectively improves the uniformity of PECVD coating.
[0029] 2. The heating control method of the present invention first turns on the main heating component and sets the target temperature required for the reaction chamber, and then starts the auxiliary heating component. Multiple auxiliary heating plates can uniformly heat the graphite boat. During the constant temperature stage of the process, the output power of each auxiliary heating plate can be adjusted. That is, the upper and lower auxiliary heating plates can be adjusted to different output powers as needed. Due to the stratification of heating heat, the heat usually rises, and the upper auxiliary heating plate will be hotter. To ensure that the graphite boat is heated evenly, the power of the upper auxiliary heating plate at the same position needs to be lower than that of the lower auxiliary heating plate. The upper and lower auxiliary heating plates of the present invention can be independently controlled to achieve uniform coating and ensure the uniformity of the coating. Attached Figure Description
[0030] Figure 1 This is a structural schematic diagram of the present invention in a specific embodiment one.
[0031] Figure 2 This is a schematic diagram of the structural principle of the multiple auxiliary heating plates of the present invention in a specific embodiment one.
[0032] Figure 3 This is a schematic diagram of the auxiliary heating plate of the present invention in a specific embodiment one.
[0033] Figure 4 yes Figure 3 Sectional view at AA.
[0034] Figure 5 This is a flowchart of the heating control method of the present invention.
[0035] Legend:
[0036] 1. Furnace shell; 2. Insulation layer; 3. Main heating assembly; 4. Quartz tube; 5. Auxiliary heating assembly; 51. Auxiliary heating plate; 511. Heating wire; 512. Fixing plate; 6. Auxiliary heating regulator; 61. First auxiliary heating regulator; 62. Second auxiliary heating regulator; 7. First groove; 8. Insulator fixing groove; 9. Main heating regulator; 10. Graphite boat. Detailed Implementation
[0037] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.
[0038] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0039] 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.
[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0041] like Figures 1 to 4 As shown, this embodiment discloses a PECVD with an auxiliary heating device, including a furnace body, which includes a furnace shell 1 and an insulation layer 2, a main heating component 3, and a quartz tube 4 disposed inside the furnace shell 1. The main heating component 3 is wrapped around the outer wall of the quartz tube 4. It also includes an auxiliary heating component 5, which includes at least two auxiliary heating plates 51, which are respectively arranged above and below the main heating component 3.
[0042] In this embodiment of PECVD with an auxiliary heating device, the auxiliary heating plate 51 of the auxiliary heating component 5 is integrated into the furnace body. Multiple auxiliary heating plates 51 are arranged around the heating wire of the main heating component 3 in the furnace body. Multiple sets of heating wires 511 are embedded in the auxiliary heating plate 51 to provide auxiliary heating to the graphite boat 10 inside the furnace body. The auxiliary heating plate 51 uses the same material as the heating wire of the main heating component 3 in the furnace body, has the same lifespan as the furnace body, and is not located inside the reaction chamber, requiring no maintenance during use. Because the auxiliary heating component 5 is located outside the reaction chamber, it will not cause contamination to the reaction chamber due to damage to the quartz sleeve, unlike auxiliary heating devices inside the reaction chamber, thus avoiding contamination caused by auxiliary heating devices. Downtime maintenance caused by heating device failure can effectively improve equipment productivity; the auxiliary heating device is located outside the reaction chamber and does not occupy space inside the reaction chamber, facilitating the entry and exit of the graphite boat 10; the auxiliary heating plate 51 is located outside the furnace wire and uses multiple sets of auxiliary heating wires for auxiliary heating. The auxiliary heating plate 51 is located above and below the graphite boat 10, both using a plate-type heating method, which provides more uniform heating compared to the heating rod structure; the auxiliary heating plate 51 can be designed as multiple heating plates according to the heating requirements of the graphite boat 10, enabling multi-segment auxiliary heating of the graphite boat, which is more conducive to the temperature control accuracy of the graphite boat 10 and effectively improves the uniformity of PECVD coating.
[0043] In this embodiment, an auxiliary heating power regulator 6 is also included, which is used to control the output power of multiple auxiliary heating plates 51 at different levels. Further, in a preferred embodiment, the auxiliary heating power regulator 6 includes a first auxiliary heating power regulator 61 and a second auxiliary heating power regulator 62, which are used to control the output power of the upper auxiliary heating plate 51 and the lower auxiliary heating plate 51, respectively.
[0044] In this embodiment, the main heating component 3 is also included, which includes multiple sets of main heating coils 31, and a main heating regulator 9 is also included. The main heating regulator 9 is used to connect to the multiple sets of main heating coils 31 and to control the heating of the multiple main heating coils 31.
[0045] In this embodiment, the system includes a main heating regulator 9, multiple sets of main heating coils 31, and multiple auxiliary heating plates 51. The main heating regulator 9 is connected to the multiple main heating coils 31 and is used to control the heating of the multiple main heating coils 31. The main heating adopts a cascade dual-loop constant temperature control. The main heating coils 31 are used for constant temperature heating of the heating system. The first auxiliary heating regulator 61 controls the multiple upper auxiliary heating plates 51 to perform constant power heating, and adjusts the output power of each upper auxiliary heating plate 51 according to the process requirements, thereby improving the temperature uniformity of each tank above the graphite boat 10. The second auxiliary heating regulator 62 controls the output power of the multiple lower auxiliary heating plates 51, thereby improving the temperature uniformity of each tank below the graphite boat 10. The length and number of auxiliary heating plates 51 are determined according to the design of the graphite boat 10 and the temperature adjustment of the graphite boat 10 required by the process, and are generally divided into 3. A section of auxiliary heating plate 51 or more auxiliary heating plates 51, the overall length of the auxiliary heating plate 51 should be greater than the total length of the graphite boat 10, to ensure that both ends of the graphite boat 10 are also heated evenly.
[0046] In this embodiment, the auxiliary heating plate 51 includes a heating wire 511 and a fixing plate 512. The fixing plate 512 is used to fix the heating wire 511. The fixing plate 512 has a first groove 7 for fixing the heating wire 511. In this embodiment, the heating wire 511 is arranged in a spiral on the fixing plate 512. In other embodiments, the heating wire 511 can be arranged in a serpentine pattern or other ways to ensure that the heating wire 511 can heat the graphite boat 10 evenly.
[0047] In this embodiment, the first groove 7 is a trapezoidal groove. The narrow opening of the trapezoidal groove ensures that the heating wire 511 is reliably and stably arranged in the first groove 7 and is not easily detached from the trapezoidal groove. In other embodiments, the first groove 7 can also be a circular groove with an opening or other shapes, as long as it can ensure that the heating wire 511 is stably and reliably fixed.
[0048] In this embodiment, the fixing plate 512 has an insulator fixing groove 8 for fixing the auxiliary heating plate 51 to the outside of the insulator string of the main heating assembly 3. Further, in a preferred embodiment, multiple auxiliary heating plates 51 are respectively arranged around the main heating assembly 3, forming an upper auxiliary heating plate 51 and a lower auxiliary heating plate 51, to provide auxiliary heating to the graphite boat 10 in the reaction chamber. The auxiliary heating plate 51 includes an auxiliary heating wire 511, which is arranged in a spiral structure. The auxiliary heating wire 511 is embedded in the trapezoidal groove of the fixing heating wire in the insulating material board (such as ceramic fiber board). The auxiliary heating plate 51 is designed with a groove structure in the insulator fixing groove 8 to facilitate fixing the auxiliary heating plate 51 to the outside of the insulator string of the main heating wire.
[0049] Example 2
[0050] like Figure 5 As shown, this embodiment provides a heating control method for PECVD with an auxiliary heating device based on Embodiment 1, the steps of which include:
[0051] Step S1: Set the target temperature required for the reaction chamber and start the main heating component 3;
[0052] Step S2: Turn on auxiliary heating component 5;
[0053] Step S3: Adjust the power of different auxiliary heating plates 51 in the auxiliary heating assembly 5 at different stages of the coating process;
[0054] Step S4: After the coating process is completed, turn off the auxiliary heating component 5.
[0055] In this embodiment, the heating control method sets the target temperature required for the reaction chamber, turns on the main heating component 3, and then starts the auxiliary heating component 5. Multiple auxiliary heating plates 51 can uniformly heat the graphite boat 10. During the constant temperature stage of the process, the output power of each auxiliary heating plate 51 can be adjusted. That is, the upper and lower auxiliary heating plates 51 can be adjusted to different output powers as needed. Due to the stratification of heating heat, the heat usually rises, so the upper auxiliary heating plate 51 will be hotter. To ensure that the graphite boat 10 is heated evenly, the power of the upper auxiliary heating plate 51 at the same position needs to be lower than that of the lower auxiliary heating plate 51. In this embodiment, the upper and lower auxiliary heating plates 51 can be controlled independently to achieve uniform coating and ensure the uniformity of the coating.
[0056] In this embodiment, step S3 specifically includes:
[0057] Step S301: During the heating stage of the PECVD reaction chamber, the auxiliary heating component 5 is powered at full capacity; the graphite boat 10 and silicon wafer are heated to the target process temperature rapidly.
[0058] Step S302: During the constant temperature stage of the process, adjust the output power of each auxiliary heating plate 51; adjust the output power of each auxiliary heating plate 51 so that the output power of the upper auxiliary heating plate 51 is less than the output power of the lower auxiliary heating plate 51;
[0059] The boat foot block absorbs more heat, so the auxiliary heating plate 51 at the boat foot has a slightly higher output power; at the boat blade, the power output of the auxiliary heating is adjusted according to the uniformity of the silicon wafer coating. If the silicon wafer coating in this tank is too thin, the auxiliary heating in this section is adjusted to increase the output power, and vice versa.
[0060] Step S303: During the deposition stage, reduce the output power of each auxiliary heating plate 51; to ensure uniform coating speed, reduce the power output of the upper and lower auxiliary heating plates 51 to a smaller value, such as reducing the output power to less than 20% of the full power.
[0061] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.
Claims
1. A PECVD with an auxiliary heating device, comprising a furnace body, the furnace body including a furnace shell (1) and an insulation layer (2), a main heating assembly (3), and a quartz tube (4) disposed within the furnace shell (1), characterized in that, The main heating assembly (3) is wound around the outer wall of the quartz tube (4) and also includes an auxiliary heating assembly (5). The auxiliary heating assembly (5) includes at least two auxiliary heating plates (51), which are respectively arranged above and below the main heating assembly (3). The auxiliary heating plate (51) includes a heating wire (511) and a fixing plate (512). The fixing plate (512) is used to fix the heating wire (511). The fixing plate (512) has a first groove (7) for fixing the heating wire (511). The fixing plate (512) has an insulator fixing groove (8) for fixing the auxiliary heating plate (51) to the outside of the insulator string of the main heating assembly (3). It also includes an auxiliary heating power regulator (6), which is used to control the output of different power of multiple auxiliary heating plates (51).
2. The PECVD with auxiliary heating device according to claim 1, characterized in that, The auxiliary heating power regulator (6) includes a first auxiliary heating power regulator (61) and a second auxiliary heating power regulator (62). The first auxiliary heating power regulator (61) and the second auxiliary heating power regulator (62) are used to control the power output of the upper auxiliary heating plate (51) and the lower auxiliary heating plate (51), respectively.
3. The PECVD with auxiliary heating device according to claim 1, characterized in that, The first groove (7) is a trapezoidal groove or a circular groove with an opening.
4. The PECVD with auxiliary heating device according to claim 1, characterized in that, The heating wires (511) are arranged in a spiral or serpentine pattern on the fixed plate (512).
5. The PECVD with auxiliary heating device according to any one of claims 1 to 4, characterized in that, The main heating assembly (3) includes multiple sets of main heating wires (31) and a main heating regulator (9). The main heating regulator (9) is connected to the multiple sets of main heating wires (31) and is used to control the multiple sets of main heating wires (31) to heat.
6. The PECVD with auxiliary heating device according to any one of claims 1 to 4, characterized in that, The total length of the multiple auxiliary heating plates (51) is not less than the total length of the graphite boat (10).
7. A heating control method for PECVD with an auxiliary heating device according to any one of claims 1 to 6, characterized in that, The steps include: Step S1: Set the target temperature required for the reaction chamber and start the main heating component (3). Step S2: Turn on the auxiliary heating component (5); Step S3: Adjust the power of different auxiliary heating plates (51) in the auxiliary heating assembly (5) at different stages of the coating process; Step S4: After the coating process is completed, turn off the auxiliary heating component (5).
8. The heating control method for PECVD with auxiliary heating device according to claim 7, characterized in that, Step S3 specifically includes: Step S301: During the heating stage of the PECVD reaction chamber, the auxiliary heating component (5) is at full power output; Step S302: During the process constant temperature stage, adjust the output power of each auxiliary heating plate (51) in the auxiliary heating assembly (5) so that the output power of the upper auxiliary heating plate (51) is less than the output power of the lower auxiliary heating plate (51); Step S303: During the process deposition stage, reduce the output power of each auxiliary heating plate (51) in the auxiliary heating assembly (5).