Temperature control system for coating process

Abstract

A temperature control system for a coating process. The temperature control system comprising: a furnace tube (1), wherein an outer-layer heating wire (11) is wound outside the furnace tube (1), and a high-temperature-resistant fixing rod (2) arranged parallel to the furnace tube (1) and wound with an inner-layer heating wire (21) is provided in the furnace tube (1); a temperature control device, which comprises a first temperature control module (31), a second temperature control module (32), a trigger board module (33), a transformer module (34) and a silicon controlled rectifier module (35), wherein the outer-layer heating wire (11) and the inner-layer heating wire (21) are respectively connected to the first temperature control module (31) and the second temperature control module (32) by means of thermocouples, the first temperature control module (31) and the second temperature control module (32) are connected to the trigger board module (33), the trigger board module (33) is connected to the transformer module (34) and the silicon controlled rectifier module (35), and the transformer module (34) is connected to a power supply module (36); and a graphite boat (4) having a cavity (41), through which the high-temperature-resistant fixing rod (2) passes. By means of heating inner and outer layers of the graphite boat (4), the temperature distribution in the whole graphite boat (4) can be effectively balanced, thereby improving the uniformity and quality of coating.

Description

A temperature control system for coating process

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on August 30, 2023, with application number 202311104023.2 and invention name “A temperature control system for a coating process”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of silicon wafer coating, and in particular to a temperature control system for a coating process. Background Art

[0004] In recent years, many countries have begun to vigorously develop solar energy to seek new impetus for economic development. Among the many solar cells, the process technology of single-crystal silicon cells has been greatly improved.

[0005] Tubular PECVD (Plasma Enhanced Chemical Vapor Deposition) is one of the most mature coating methods at present and is still one of the mainstream coating methods. Efficiency requirements have led to larger and larger cell sizes, and production capacity demands have led to more and more specifications for graphite boat loading. The loading capacity of a single graphite boat has grown from 200 cells at the beginning to 600 cells now. Technological discoveries have shown that as the loading capacity of a graphite boat increases, it is difficult to better control the electric field, thermal field, and gas field required for the reaction during coating. The ensuing problem is that the film color uniformity between the outer and inner boat pages after coating is quite different. The industry's solution is to split the large graphite boat into two small graphite boats, so that the overall width of the graphite boat becomes smaller. For example, Germany's centrotherm uses a dual-tube feed to a dual boat, while Red Sun and Jiejiawei Chuang use a single-tube feed to a dual boat. The former changes the coating difference from between sheets to between tubes, and it cannot be processed in the same tube, and the gas field cannot be unified; although the latter is in one tube, because two graphite boats are powered by electrode rods and graphite blocks, the electric field between the two graphite boats cannot be unified.

[0006] Summary of the Invention

[0007] To this end, the technical problem to be solved by this application is to overcome the problem in the prior art that the thermal field during the process of increasing the specifications of the graphite boat cannot accurately lead to differences between the battery cells in the middle and outer parts of the graphite boat after the process, and the problem that a unified electric field and gas field cannot be formed when the graphite boat is cut into small graphite boats for coating.

[0008] In order to solve the above technical problems, the present application provides a temperature control system for a coating process, comprising: a furnace tube, an outer heating wire is wound around the outer tube, and a high-temperature resistant fixed rod is arranged inside the furnace tube and is arranged parallel to the furnace tube and is wound around the inner heating wire; a temperature control device, comprising a first temperature control module, a second temperature control module, a trigger plate module, a transformer module, and a thyristor module, the outer heating wire and the inner heating wire are respectively connected to the first temperature control module and the second temperature control module through thermocouples, the first temperature control module and the second temperature control module are connected to the trigger plate module, the trigger plate module is respectively connected to the transformer module and the thyristor module, and the transformer module The block is connected to the power module; the graphite boat has a cavity for the high-temperature resistant fixing rod to pass through; wherein, the temperature control module is used to receive the signal of the thermocouple to obtain the real-time temperature value of the furnace tube; the temperature control module is used to determine whether the temperature of the furnace tube needs to be adjusted by comparing the real-time temperature value with the set target temperature. If the real-time temperature value is lower than or higher than the target temperature, the temperature control module will send a signal to the trigger board module, and transmit the signal to the thyristor module through the trigger board module; the thyristor is used to control the on and off of the current after receiving the signal, thereby realizing the increase or decrease of the furnace tube temperature.

[0009] In one embodiment of the present application, the graphite boat includes a plurality of outer graphite boat blades and inner graphite boat blades that are arranged in parallel and staggered, and the cavity is located between the outer graphite boat blades and the inner graphite boat blades that are staggered.

[0010] In one embodiment of the present application, a first graphite rod is connected between the electrodes of all the outer graphite boat blades located on the same side, a first conductive block is mounted on the first graphite rod, the first conductive block is provided with a first electrode hole, and both ends of the first graphite rod are fastened by a first graphite nut.

[0011] In one embodiment of the present application, a second graphite rod is connected between the electrodes of all the inner graphite boat blades located on the same side, a second conductive block is mounted on the second graphite rod, the second conductive block is provided with a second electrode hole, and both ends of the second graphite rod are fastened by second graphite nuts.

[0012] In one embodiment of the present application, the first conductive block and the second conductive block are 150±10 mm apart.

[0013] In one embodiment of the present application, a third graphite rod is vertically passed through the boat ears of each of the outer graphite boat blade and the inner graphite boat blade, and both ends of the third graphite rod are fastened by third graphite nuts.

[0014] In one embodiment of the present application, ceramic rods are vertically passed through the plurality of outer graphite boat blades and the inner graphite boat blades.

[0015] In one embodiment of the present application, a ceramic ring is sleeved on the ceramic rod between the adjacent outer graphite boat blades and the adjacent inner graphite boat blades.

[0016] In one embodiment of the present application, the length of the graphite boat is 1500±50 mm.

[0017] In one embodiment of the present application, the furnace tube and the graphite boat are arranged in parallel.

[0018] The above technical solution of the present application has the following advantages over the prior art: the temperature control system of a coating process described in the present application forms a two-layer heating system by adding a row of heating devices parallel to the furnace tube in the center of the furnace tube. When the graphite boat enters, these heating devices will penetrate the middle part of the graphite boat. The graphite boat is energized with current through the same furnace tube through the electrode rods and electrode holes, which improves the thermal field uniformity of the battery cell coating while ensuring the uniformity of the electric field and the uniformity of the gas field. This two-layer heating system and electrode energization design can achieve better thermal and electric field control. By heating the inner and outer layers of the graphite boat, the temperature distribution of the entire graphite boat can be effectively balanced, and the uniformity and quality of the coating can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the contents of this application easier to understand, the application is further described in detail below based on the specific embodiments of this application and in conjunction with the accompanying drawings.

[0020] Figure 1 is a schematic diagram of a heating wire fixed in the middle of a furnace tube.

[0021] Figure 2 is a schematic diagram of the inner layer heating cross section.

[0022] Figure 3 is a schematic diagram of the temperature control module.

[0023] FIG4 is a schematic diagram of the top view of the graphite boat.

[0024] FIG5 is a side view of a graphite boat.

[0025] Explanation of the reference numerals in the specification: 1. furnace tube; 11. outer heating wire; 2. high temperature resistant fixing rod; 21. inner heating wire; 31. first temperature control module; 32. second temperature control module; 33. trigger plate module; 34. transformer module; 35. thyristor module; 36. power supply module; 4. graphite boat; 41. cavity; 42. outer graphite boat blade; 43. inner graphite boat blade; 44. first graphite rod; 441. first graphite nut; 45. first conductive block; 451. first electrode hole; 46. second graphite rod; 461. second graphite nut; 47. second conductive block; 471. second electrode hole; 48. third graphite rod; 481. third graphite nut; 49. ceramic rod; 491. ceramic ring. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present application and implement it, but the embodiments are not intended to limit the present application.

[0027] In this application, if there is a description of directions (up, down, left, right, front and back), it is only for the convenience of describing the technical solution of this application, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on this application.

[0028] In this application, "several" means one or more, "multiple" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself; "above," "below," and "within" are understood to include the number itself. In the description of this application, the use of "first" or "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0029] In this application, unless otherwise expressly defined, terms such as "disposed," "installed," and "connected" should be interpreted broadly. For example, they may refer to direct connection or indirect connection through an intermediate medium; fixed connection or detachable connection or integral molding; mechanical connection or electrical connection or mutual communication; and internal connection between two components or interaction between two components. Persons skilled in the art can reasonably determine the specific meanings of these terms in this application based on the specific content of the technical solution.

[0030] 1 to 5 , a temperature control system for a coating process of the present application includes: a furnace tube 1, an outer heating wire 11 being wound around the outer tube, and a high-temperature resistant fixed rod 2 being arranged parallel to the furnace tube and wound around the inner heating wire 21; a temperature control device including a first temperature control module 31, a second temperature control module 32, a trigger plate module 33, a transformer module 34, and a thyristor module 35. The outer heating wire 11 and the inner heating wire 21 are respectively connected to the first temperature control module 31 and the second temperature control module 32 through thermocouples. The first temperature control module 31 and the second temperature control module 32 are connected to the trigger plate module 33. The trigger plate module 33 is respectively connected to the transformer module 34 and the thyristor module 35, the transformer module 34 is connected to the power module 36; the graphite boat 4 has a cavity 41 for the high-temperature resistant fixing rod 2 to pass through; wherein, the temperature control module is used to receive the signal of the thermocouple to obtain the real-time temperature value of the furnace tube 1; the temperature control module is used to determine whether the temperature of the furnace tube 1 needs to be adjusted by comparing the real-time temperature value with the set target temperature. If the real-time temperature value is lower than or higher than the target temperature, the temperature control module will send a signal to the trigger board module 33, and transmit the signal to the thyristor module 35 through the trigger board module 33; the thyristor is used to control the on and off of the current after receiving the signal, thereby achieving an increase or decrease in the temperature of the furnace tube 1.

[0031] In some embodiments, the high temperature resistant fixing rod 2 can be made of ceramic material and connected to the furnace tube 1 through a flange.

[0032] In some embodiments, the first temperature control module 31 and the second temperature control module 32 may use a PID controller; the trigger board module 33 may be a solid-state relay trigger board; and the transformer module 34 may be an AC transformer.

[0033] In some embodiments, the graphite boat 4 includes a plurality of outer graphite boat blades 42 and inner graphite boat blades 43 that are arranged in parallel and staggered, and the cavity 41 is located between the outer graphite boat blades 42 and the inner graphite boat blades 43 that are staggered.

[0034] In some embodiments, a first graphite rod 44 is connected between the electrodes of all the outer graphite boat blades 42 located on the same side, a first conductive block 45 is mounted on the first graphite rod 44, and the first conductive block 45 is provided with a first electrode hole 451. The two ends of the first graphite rod 44 are fastened by a first graphite nut 441.

[0035] In some embodiments, a second graphite rod 46 is connected between the electrodes of all the inner graphite boat blades 43 located on the same side, a second conductive block 47 is mounted on the second graphite rod 46, and the second conductive block 47 is provided with a second electrode hole 471. The two ends of the second graphite rod 46 are fastened by a second graphite nut 461.

[0036] In some embodiments, the first conductive block 45 and the second conductive block 47 are spaced 150 ± 10 mm apart. Without interfering with the movement of the furnace tube 1 into and out of the boat, the mainframe's inner heating device extends through the interior of the graphite boat 4. This dual heating layer ensures uniform thermal field distribution across the two sections of the graphite boat 4.

[0037] In some embodiments, a third graphite rod 48 is vertically passed through the boat ears of the outer graphite boat blade 42 and the inner graphite boat blade 43 , and both ends of the third graphite rod 48 are fastened by third graphite nuts 481 .

[0038] In some embodiments, a plurality of the outer graphite boat blades 42 and the inner graphite boat blades 43 are further vertically penetrated by ceramic rods 49 .

[0039] In some embodiments, a ceramic ring 491 is sleeved on the ceramic rod 49 between the adjacent outer graphite boat blades 42 and the inner graphite boat blades 43 .

[0040] In some embodiments, the length of the graphite boat 4 is 1500±50 mm. The shorter design of the graphite boat 4 with a length of 1500 mm improves the electrical uniformity inside the furnace tube 1.

[0041] In some embodiments, the furnace tube 1 and the graphite boat 4 are arranged in parallel.

[0042] During the coating process, the graphite boat 4 enters the furnace tube 1. The high-temperature-resistant fixing rod 2 passes through the cavity 41 of the graphite boat 4 and extends to the rear end of the boat. The inner heating filament 21 heats the interior of the graphite boat 4, while the outer heating filament 11 heats the exterior of the furnace tube 1. The two heating modules work together to balance the thermal field, thereby improving the film quality. This provides a stable temperature environment, preventing rapid temperature fluctuations during the coating process, thereby improving the quality and uniformity of the film. Furthermore, by placing the heating source both inside and outside the graphite boat 4, the film formation and deposition process can be better controlled, enhancing the coating effect.

[0043] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application is described in detail with reference to examples, ordinary technicians in this field should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be included in the scope of the claims of the present application.

Claims

1. A temperature control system for a coating process, characterized in that: include: A furnace tube (1) having an outer heating wire (11) wound around it, and having a high temperature resistant fixing rod (2) arranged parallel to the furnace tube and wound around an inner heating wire (21) arranged inside it; a temperature control device comprising a first temperature control module (31), a second temperature control module (32), a trigger plate module (33), a transformer module (34), and a thyristor module (35), wherein the outer heating wire (11) and the inner heating wire (21) are respectively connected to the first temperature control module (31) and the second temperature control module (32) through a thermocouple, the first temperature control module (31) and the second temperature control module (32) are connected to the trigger plate module (33), the trigger plate module (33) is respectively connected to the transformer module (34) and the thyristor module (35), and the transformer module (34) and the thyristor module (35) are respectively connected to the trigger plate module (33). The pressure regulator module (34) is connected to the power supply module (36); the graphite boat (4) has a cavity (41) for the high temperature resistant fixing rod (2) to pass through; wherein the temperature control module is used to receive the signal of the thermocouple to obtain the real-time temperature value of the furnace tube (1); the temperature control module is used to determine whether the temperature of the furnace tube (1) needs to be adjusted by comparing the real-time temperature value with the set target temperature; if the real-time temperature value is lower than or higher than the target temperature, the temperature control module will send a signal to the trigger board module (33), and transmit the signal to the thyristor module (35) through the trigger board module (33); the thyristor is used to control the on and off of the current after receiving the signal, so as to achieve the increase or decrease of the temperature of the furnace tube (1).

2. A temperature control system for a coating process according to claim 1, characterized in that: The graphite boat (4) comprises a plurality of outer graphite boat blades (42) and inner graphite boat blades (43) which are arranged in parallel and staggered, and the cavity (41) is located between the outer graphite boat blades (42) and the inner graphite boat blades (43) which are staggered.

3. A temperature control system for a coating process according to claim 2, characterized in that: A first graphite rod (44) is connected between the electrodes of all the outer graphite boat blades (42) located on the same side, a first conductive block (45) is mounted on the first graphite rod (44), the first conductive block (45) is provided with a first electrode hole (451), and both ends of the first graphite rod (44) are fastened by first graphite nuts (441).

4. A temperature control system for a coating process according to claim 3, characterized in that: A second graphite rod (46) is connected between the electrodes of all the inner graphite boat blades (43) located on the same side, a second conductive block (47) is mounted on the second graphite rod (46), the second conductive block (47) is provided with a second electrode hole (471), and both ends of the second graphite rod (46) are fastened by second graphite nuts (461).

5. A temperature control system for a coating process according to claim 4, characterized in that: The first conductive block (45) and the second conductive block (47) are spaced 150±10 mm apart.

6. The temperature control system for a coating process according to claim 2, characterized in that: The outer graphite boat blade (42) and the inner graphite boat blade (43) are each vertically provided with a third graphite rod (48) through the boat ears, and both ends of the third graphite rod (48) are fastened by third graphite nuts (481).

7. The temperature control system for a coating process according to claim 2, characterized in that: Ceramic rods (49) are vertically penetrated through the plurality of outer graphite boat blades (42) and the inner graphite boat blades (43).

8. A temperature control system for a coating process according to claim 7, characterized in that: A ceramic ring (491) is sleeved on the ceramic rod (49) between the adjacent outer graphite boat blades (42) and the inner graphite boat blades (43).

9. The temperature control system for coating process according to claim 2, characterized in that: The length of the graphite boat (4) is 1500±50 mm.

10. The temperature control system for coating process according to claim 1, characterized in that: The furnace tube (1) and the graphite boat (4) are arranged in parallel.

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