Reaction chamber and coating process method

Abstract

The invention provides a reaction chamber, and belongs to the technical field of coating equipment, the reaction chamber is used for accommodating a battery silicon wafer and carrying out ALD coating on the battery silicon wafer by inputting process gas, the reaction chamber comprises an outer cavity, the outer cavity is provided with a reaction cavity capable of accommodating the process gas, the process gas forms a reaction area in the reaction cavity, and the outer cavity is used for accommodating the process gas. Coating a film on the battery silicon wafer in the reaction area; the heating element is arranged in the reaction cavity and is used for heating the battery silicon wafer in the reaction area; the gas curtain unit forms a gas curtain in the reaction cavity by feeding and discharging gas in the reaction cavity, the gas curtain is arranged on the outer side of the reaction area, and the range of the reaction area in the reaction cavity is limited through the gas curtain; the heating efficiency of the reaction chamber on the battery silicon wafer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of film coating equipment, and in particular to a reaction chamber and a film coating process method. Background Art

[0002] In the production process of solar cell silicon wafers, a thin film deposition process is used to coat the silicon wafers. The aluminum oxide film prepared by ALD is recognized by the industry as the preparation method with the best film quality.

[0003] At present, the reaction chamber of the ALD equipment consists of an inner cavity and an outer cavity. Figure 1 As shown, when the temperature of the cell silicon wafer in the carrier reaches the process required temperature, the thin film deposition process can be carried out. The entire heating process is to heat the inner cavity first and then heat the carrier through the heating element attached to the outer cavity wall to make the cell silicon wafer reach the temperature requirement. When the reaction chamber meets the process requirements, the reaction sources trimethylaluminum (TMA) and water (H2O) are introduced into the reaction chamber to deposit a dense aluminum oxide film on the crystal surface, thereby achieving the purpose of passivating the crystalline silicon surface.

[0004] In the above structure, TMA is directly injected into the inner cavity. After the coating process is completed, only residual dust will remain in the inner cavity, and the inner cavity only needs to be cleaned regularly. However, the heating element of this method indirectly heats the battery silicon wafer, and there is an inner cavity in the middle that needs to be heated first, which affects the heating effect and increases energy consumption.

[0005] Therefore, the technical problem of the prior art is: how to improve the heating efficiency of the reaction chamber on the battery silicon wafer. Summary of the invention

[0006] The embodiment of the present application provides a reaction chamber, which solves the technical problem in the prior art of how to improve the heating efficiency of the reaction chamber on the battery silicon wafer, thereby achieving the goal of improving the heating efficiency of the reaction chamber on the battery silicon wafer.

[0007] An embodiment of the present application provides a reaction chamber for accommodating battery silicon wafers, and coating the battery silicon wafers by inputting process gas. The reaction chamber comprises: an outer cavity, wherein the outer cavity is constructed with a reaction chamber that can accommodate the process gas, and the process gas forms a reaction zone in the reaction chamber to coat the battery silicon wafers in the reaction zone; a heating element, wherein the heating element is arranged in the reaction chamber and is used to heat the battery silicon wafers in the reaction zone; and an air curtain unit, wherein the air curtain unit forms an air curtain in the reaction chamber by letting gas enter and exit the reaction chamber, wherein the air curtain is arranged outside the reaction zone, and the range of the reaction zone in the reaction chamber is limited by the air curtain.

[0008] Preferably, the air curtain contacts the inner wall of the reaction chamber to limit the scope of the reaction zone; or, a plurality of air curtain units are provided, and the air curtains between adjacent air curtain units are combined with each other to limit the scope of the reaction zone.

[0009] Preferably, two air curtain units are provided, and the two air curtain units are arranged in the circumference of the reaction zone, so that an air curtain of a certain shape is arranged in the circumference of the reaction zone.

[0010] Preferably, the two air curtain units are arranged on both sides of the reaction zone in the width direction to limit the expansion of the reaction zone in the width direction.

[0011] Preferably, the reaction chamber further comprises an air inlet and an air outlet for the process gas to enter and exit, the air inlet and the air outlet are respectively connected and arranged on the outer cavity, and the air inlet and the air outlet are located at the upper and lower sides of the height direction of the reaction zone.

[0012] Preferably, the air curtain unit and the process gas share the gas outlet.

[0013] Preferably, the air outlet is located in the middle of the two air curtain units, and the two air curtains are brought closer to each other through the air outlet to reduce the volume of the lower part of the reaction zone in the height direction.

[0014] Preferably, the air curtain unit comprises an air curtain inlet and an air curtain outlet, wherein the air curtain inlet and the air curtain outlet pass through the outer cavity and are connected to the reaction chamber; wherein a flow equalizing plate is provided at the output end of the air curtain inlet and the input end of the air curtain outlet, and the air curtain unit forms an air curtain through the two flow equalizing plates.

[0015] Preferably, the inlet and outlet gases of the gas curtain and the inlet and outlet gases of the reaction zone are divided into two sets; the gas curtain has a first movement direction in the reaction chamber, and the process gas has a second movement direction in the reaction chamber, and the first movement direction and the second movement direction are consistent or substantially consistent.

[0016] A coating process method comprises: starting the heating element to heat the battery silicon wafer in the reaction zone; introducing a protective gas with an initial velocity into the air curtain unit so that the air curtain unit establishes the air curtain; after the air curtain unit establishes the air curtain, introducing a process gas into the reaction zone in the middle of the air curtain; after stopping introducing the process gas into the reaction zone, stopping introducing the protective gas with an initial velocity into the air curtain unit.

[0017] The above one or more technical solutions in the embodiments of the present application have at least one or more of the following technical effects:

[0018] 1. In the present application, an air curtain unit is used to replace the inner cavity. The advantages are: first, the air curtain formed by the air curtain unit can isolate the dust generated by the reaction while still having the dust isolation function of the inner cavity; second, the heating element can directly heat the battery silicon wafers in the reaction zone by passing through the air curtain, avoiding the need to heat the inner cavity first in the conventional reaction chamber structure, and the heating is fast and the heating energy consumption is low; it solves the technical problem of how to improve the heating efficiency of the reaction chamber for the battery silicon wafers in the prior art; and achieves the goal of improving the heating efficiency of the reaction chamber for the battery silicon wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the cross-sectional structure of an existing reaction chamber in the main view direction;

[0020] Figure 2 A schematic diagram of a cross-sectional structure of a reaction chamber from the main view Figure 1 ;

[0021] Figure 3 A schematic diagram of a cross-sectional structure of a reaction chamber from the main view Figure 2 .

[0022] Figure numerals: 100, outer cavity; 200, heating element; 300', inner cavity; 300, air curtain unit; 310, air curtain; 320, air curtain air inlet; 330, air curtain air outlet; 400, work station; 500, air inlet; 510, first air inlet; 520, second air inlet; 600, air outlet; 700, reaction zone; 710, first reaction part; 720, second reaction part. DETAILED DESCRIPTION

[0023] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of this application, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application.

[0024] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] A reaction chamber, reference Figure 2 and Figure 3 , used to accommodate battery silicon wafers, and to coat the battery silicon wafers by inputting process gases. The reaction chamber can be an ALD coating chamber, or a coating chamber for other processes. The reaction chamber includes an outer cavity 100, a heating element 200, and an air curtain unit 300; the heating element 200 and the air curtain unit 300 are both arranged in the outer cavity 100, the heating element 200 is used to heat the battery silicon wafers in the outer cavity 100, and the air curtain unit 300 is used to form an air curtain 310 to limit the range of movement of the process gas after entering the outer cavity 100.

[0027] The outer cavity 100, reference Figure 2 , which is a basic shell of a device. The outer cavity 100 is constructed with a reaction chamber that can accommodate process gas, and the process gas forms a reaction zone 700 in the reaction chamber to coat the battery silicon wafers in the reaction zone 700; wherein, regarding the relationship between the battery silicon wafers and the reaction zone 700, the battery silicon wafers can be directly arranged in the reaction zone 700 so that the heating element 200 has the best heating effect on the battery silicon wafers; or a carrier can be used as a limiting tool for the battery silicon wafers to ensure that the battery silicon wafers are stably arranged in the reaction zone 700, which is also convenient for a large number of battery silicon wafers to be placed and taken out conveniently.

[0028] For example, a long strip carrier is designed to evenly accommodate the cell silicon wafers, and the cell silicon wafers are arranged in the same direction in the carrier so that the process gas can move toward the cell silicon wafers at the same angle. If all the cell silicon wafers are arranged vertically on the carrier, the process gas can move from top to bottom over the surface of the cell silicon wafers.

[0029] In addition, it can be understood that the outer cavity 100 is provided with an inlet 500 and an outlet 600 for the process gas to enter and exit, and the inlet 500 and the outlet 600 are located at the upper and lower sides of the height direction of the reaction zone 700, and the inlet 500 and the outlet 600 are respectively connected to the outer cavity 100 to realize the process gas moving from top to bottom or from bottom to top. The above-mentioned inlet 500 and the outlet 600 are arranged up and down, so that the movement path of the process gas in the reaction zone 700 is short, and the utilization rate of the process gas and the response efficiency of the coating are improved. Among them, it is preferred to arrange the battery silicon wafer in the middle of the entire reaction zone 700, where the process gas concentration is uniform, the flow rate is uniform, and the flow direction is consistent; to avoid the battery silicon wafer being located in the first reaction section 710 at the upper part of the reaction zone 700, where the process gas distribution is not uniform or the mixing of multiple process gases is not uniform; and to avoid the battery silicon wafer being located in the second reaction section 720 at the lower part of the reaction zone 700, where the gas outlet 600 affects the flow rate and flow direction of the process gas.

[0030] Heating element 200, reference Figure 2 The heating element 200 is arranged in the reaction chamber to heat the cell silicon wafer in the reaction zone 700. The common heating element 200 is a heating wire that generates heat through electric current. It is understandable that the heating element 200 is arranged close to the inner wall of the reaction chamber so that the reaction chamber still retains a large space after the heating element 200 is arranged, which is convenient for designing the air curtain unit 300.

[0031] Air curtain unit 300, reference Figure 2 , used to form a gas barrier to achieve partitioning in the reaction chamber. The air curtain unit 300 is used to replace the traditional inner cavity 300'. In addition to facilitating the heating of the heating element 200, it is also beneficial to reduce the size of the outer cavity 100, so that the volume of the reaction chamber is reduced. The air curtain unit 300 forms an air curtain 310 in the reaction chamber by letting gas enter and exit the reaction chamber, wherein the air curtain 310 is arranged on the outside of the reaction zone 700, and the range of the reaction zone 700 in the reaction chamber is limited by the air curtain 310. And the faster the flow rate of the protective gas constituting the air curtain 310, the better the isolation effect of the formed air curtain 310. When the flow rate of the protective gas is greater than the diffusion rate of the process gas in the reaction zone 700, the process gas cannot pass through the air curtain 310, ensuring that dust will not overflow from the reaction zone 700.

[0032] In order to improve the isolation range of the air curtain unit 300, it can be understood that the air curtain 310 contacts the inner wall of the reaction chamber, that is, the two types of barriers are combined to expand the restricted range, thereby limiting the range of the reaction zone 700; or, the air curtain unit 300 is provided with multiple air curtains, and the air curtains 310 between adjacent air curtain units 300 are combined with each other, that is, combined into a larger gas barrier, thereby limiting the range of the reaction zone 700. Conventionally, there are two air curtain units 300, and the two air curtain units 300 are respectively arranged in the circumference of the reaction zone 700, so that the air curtains 310 of the form are arranged in the circumference of the reaction zone 700, isolating the reaction zone 700 in a local position of the reaction chamber.

[0033] Exemplarily, the reaction chamber is in the shape of a long strip, and the reaction zone 700 is preferably also designed as a long strip based on the shape of the reaction chamber and the principle of maximizing utilization. In this case, the distance between the reaction zone 700 and the reaction chamber in the width direction is generally the largest, so the two air curtain units 300 are arranged on both sides of the width direction of the reaction zone 700 to limit the expansion of the reaction zone 700 in the width direction of the reaction zone 700. In order to improve the restriction on the reaction zone 700, combined with the aforementioned barrier combination logic, the two air curtains 310 can be in contact with the inner walls on both sides of the length direction of the reaction chamber to form a blockade of the reaction zone 700 in the width and length directions; or the two air curtains 310 can be in contact with the inner walls on both sides of the height direction of the reaction chamber to form a blockade of the width and height directions of the reaction zone 700; similarly, the two air curtains 310 can be in contact with the inner walls of the reaction chamber on multiple sides at the same time to more comprehensively block the reaction zone 700. In addition, an air curtain unit 300 in the form of an air curtain 310 may be added to replace the inner wall of the reaction chamber, thereby more accurately limiting the range of the reaction zone 700 and reducing the inner wall area that contacts the dust during the reaction.

[0034] The structure of the air curtain unit 300 includes an air curtain air inlet 320 and an air curtain air outlet 330, which pass through the outer cavity 100 and are connected to the reaction chamber; wherein, the output end of the air curtain air inlet 320 and the input end of the air curtain air outlet 330 are provided with a flow equalizing plate (not shown in the figure), and the air curtain unit 300 forms an air curtain 310 through the two flow equalizing plates.

[0035] refer to Figure 2 and Figure 3 The air curtain inlet 320 and the air inlet 500 on the outer cavity 100 are independent of each other to allow gas to enter respectively; and the air curtain outlet 330 and the air outlet 600 on the outer cavity 100 have two design structures.

[0036] The first structure of the air curtain air outlet 330 and the air outlet 600 on the outer cavity 100 is as follows: Figure 2, the air curtain outlet 330 and the air outlet 600 of the outer chamber 100 are combined, and only one air outlet 600 located below the reaction zone 700 is retained. The air outlet 600 is used for the output of process gas, and also attracts the air curtain 310 located outside the reaction zone 700 to approach the air outlet 600, and makes the protective gas constituting the air curtain 310 also output from the air outlet 600. It should be noted that this structural form is conducive to making the lower part of the air curtain 310 close to the reaction zone 700, so that without affecting the normal coating of the battery silicon wafer, it is conducive to reducing the volume of the second reaction part 720 of the reaction zone 700, and then reducing the outer size of the entire reaction chamber. It should be noted that, based on the aforementioned requirement that the lower portion of the air curtain 310 is close to the second reaction portion 720, it means that the lower portion of the air curtain 310 requires a space close to the second reaction portion 720. Therefore, a distance must be left between the work station 400 for accommodating the carrier or directly accommodating the battery silicon wafer in the reaction area 700 and the gas outlet 600, so that the protective gas constituting the air curtain 310 can move out from the gas outlet 600 through this distance.

[0037] Specifically, the gas outlet 600 is located in the middle of the two gas curtain units 300, and the two gas curtains 310 are brought closer to each other through the gas outlet 600 to reduce the volume of the lower part of the reaction zone 700 in the height direction; it also reduces the contact of the process gas with the bottom inner wall of the reaction chamber. In other words, the two gas curtains 310 are guided to form a U-shaped gas barrier to reduce the contact between the process gas and the inner wall of the reaction chamber. Only the upper part of the reaction zone 700 is contacted by the process gas, making subsequent maintenance convenient. It can be emphasized that after the protective gas and the process gas are output from the same gas outlet 600, they can be separated again through the process, and the protective gas can be recycled.

[0038] The second structure of the air curtain air outlet 330 and the air outlet 600 on the outer cavity 100 is as follows: Figure 3 , the air curtain outlet 330 and the outlet 600 of the reaction zone 700 are divided into two sets, which are independent and spaced apart. With such a design, the air curtain 310 has a first movement direction in the reaction chamber, and the process gas has a second movement direction in the reaction chamber. Preferably, the first movement direction and the second movement direction are consistent or substantially consistent, so that the air curtain 310 is close to the reaction zone 700, and the movement of the protective gas and the process gas does not interfere with each other. It should be noted that the second movement direction of the process gas movement has a preferred direction relative to the battery silicon wafer. Specifically, when the battery wafer is vertically arranged, the process gas preferably flows vertically from top to bottom along the battery wafer. In this case, the air curtain 310 is also preferably arranged to flow vertically from top to bottom along the battery wafer in the reaction chamber.

[0039] A coating process method suitable for the above-mentioned reaction chamber is specifically as follows: starting the heating element 200 to heat the battery silicon wafer in the reaction zone 700; introducing a protective gas with an initial velocity into the air curtain unit 300, so that the air curtain unit 300 establishes an air curtain 310; after the air curtain unit 300 establishes the air curtain 310, introducing a process gas into the reaction zone 700 in the middle of the air curtain 310; after stopping the introduction of the process gas into the reaction zone 700, stopping the introduction of the protective gas with the initial velocity into the air curtain unit 300.

[0040] It should be noted that the order of heating the cell silicon wafer first and establishing the air curtain 310 can be interchanged, that is, the air curtain 310 can be established first, and then the cell silicon wafer can be heated by the heating element 200. In addition, after stopping the introduction of process gas into the reaction zone 700, the reaction chamber can be kept running for a period of time, and after the process gas in the reaction zone 700 is completely exhausted, the introduction of the protective gas with the initial velocity into the air curtain unit 300 can be stopped. Whether the process gas is exhausted can be determined by detecting whether the gas exhausted from the gas outlet 600 contains the process gas; or it can be determined by relying on experience to determine the aforementioned time for continuing to maintain the operation of the reaction chamber.

[0041] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0042] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A reaction chamber for accommodating battery silicon wafers, coating the battery silicon wafers by inputting process gas, characterized in that: The reaction chamber comprises: An outer cavity (100), wherein the outer cavity (100) is constructed with a reaction chamber capable of accommodating process gas, and the process gas forms a reaction zone (700) in the reaction chamber to coat the cell silicon wafer in the reaction zone (700); A heating element (200), the heating element (200) being arranged in the reaction chamber and used for heating the cell silicon wafer in the reaction zone (700); and An air curtain unit (300), wherein the air curtain unit (300) forms an air curtain (310) in the reaction chamber by letting gas enter and exit the reaction chamber, wherein the air curtain (310) is arranged outside the reaction zone (700), and the range of the reaction zone (700) in the reaction chamber is limited by the air curtain (310).

2. The reaction chamber according to claim 1, characterized in that: The air curtain (310) contacts the inner wall of the reaction chamber, thereby limiting the scope of the reaction zone (700); or, the air curtain unit (300) is provided with a plurality of air curtain units (300), and the air curtains (310) between adjacent air curtain units (300) are combined with each other, thereby limiting the scope of the reaction zone (700).

3. The reaction chamber according to claim 1, characterized in that: Two air curtain units (300) are provided, and the two air curtain units (300) are arranged in the circumference of the reaction zone (700), so that an air curtain (310) in the form of air curtain is arranged in the circumference of the reaction zone (700).

4. The reaction chamber according to claim 3, characterized in that: The two air curtain units (300) are disposed on both sides of the reaction zone (700) in the width direction to limit the expansion of the reaction zone (700) in the width direction thereof.

5. The reaction chamber according to claim 3, characterized in that: The reaction chamber further comprises an air inlet (500) and an air outlet (600) for the process gas to enter and exit, the air inlet (500) and the air outlet (600) are respectively connected and arranged on the outer cavity (100), and the air inlet (500) and the air outlet (600) are located at the upper and lower sides of the height direction of the reaction zone (700).

6. The reaction chamber according to claim 5, characterized in that: The air curtain unit (300) and the process gas share the gas outlet (600).

7. The reaction chamber according to claim 6, characterized in that: The gas outlet (600) is located in the middle of the two air curtain units (300), and the two air curtains (310) are brought closer to each other through the gas outlet (600) to reduce the volume of the lower part of the reaction zone (700) in the height direction.

8. The reaction chamber according to claim 1, characterized in that: The air curtain unit (300) comprises an air curtain air inlet (320) and an air curtain air outlet (330), wherein the air curtain air inlet (320) and the air curtain air outlet (330) pass through the outer cavity (100) and are connected to the reaction cavity; wherein the output end of the air curtain air inlet (320) and the input end of the air curtain air outlet (330) are provided with flow equalizing plates, and the air curtain unit (300) forms an air curtain (310) through the two flow equalizing plates.

9. The reaction chamber according to claim 1, characterized in that: The inlet and outlet gases of the gas curtain (310) and the inlet and outlet gases of the reaction zone (700) are divided into two sets; the gas curtain (310) has a first movement direction in the reaction chamber, and the process gas has a second movement direction in the reaction chamber, and the first movement direction and the second movement direction are consistent or substantially consistent.

10. A coating process, characterized in that: Using the reaction chamber according to any one of claims 1 to 9, comprising: Starting the heating element (200) to heat the cell silicon wafer in the reaction zone (700); Introducing a protective gas having an initial velocity into the air curtain unit (300), so that the air curtain unit (300) establishes the air curtain (310); After the gas curtain unit (300) establishes the gas curtain (310), introducing a process gas into the reaction zone (700) in the middle of the gas curtain (310); After the process gas is stopped from being introduced into the reaction zone (700), the protective gas having the initial velocity is stopped from being introduced into the gas curtain unit (300).

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