Reaction chamber and film coating process method

Abstract

The present invention provides a reaction chamber, which belongs to the technical field of coating equipment and is used to accommodate battery silicon wafers and perform ALD coating on 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, which 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 entering and exiting gas in the reaction chamber, wherein the air curtain is arranged outside the reaction zone and limits the range of the reaction zone in the reaction chamber by the air curtain, so as to improve the heating efficiency of the reaction chamber on the battery silicon wafers.

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, 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 ALD equipment consists of an inner cavity and an outer cavity. Figure 1 As shown, thin film deposition can begin when the temperature of the cell silicon wafers within the carrier reaches the required process temperature. The entire heating process involves heating the inner chamber and then the carrier, using heaters attached to the outer chamber walls to bring the cell silicon wafers to the required temperature. When the reaction chamber reaches the required process temperature, the reaction sources trimethylaluminum (TMA) and water (H2O) are introduced into the chamber, depositing a dense aluminum oxide film on the crystal surface, thereby 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 the inner cavity will have residual dust, which can be cleaned regularly. However, the heating element in 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 solar silicon wafers, and coating the solar 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 solar 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 solar 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 entering and exiting gas in 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 range 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 range of the reaction zone.

[0009] Preferably, two air curtain units are provided, and the two air curtain units are separately arranged in the circumference of the reaction zone, so that the air curtains are 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 includes an air curtain inlet and an air curtain outlet, and the air curtain inlet and the air curtain outlet pass through the outer cavity and are connected to the reaction chamber; wherein, the output end of the air curtain inlet and the input end of the air curtain outlet are provided with flow equalizing plates, 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 solar cell 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 the introduction of the process gas into the reaction zone, stopping the introduction of the protective gas with the 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 This is a schematic diagram of the cross-sectional structure of an existing reaction chamber from the main view direction;

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

[0021] Figure 3 A schematic diagram of the main cross-sectional structure of a reaction chamber 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 used solely to distinguish the objects being described and do not convey any order or technical meaning. The terms "connection" and "coupling" used in this application, unless otherwise specified, include both direct and indirect connections (couplings). In the description of this application, it should be understood that the terms "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," and the like, indicating positions or positional relationships, are based on the positions or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0024] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it 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. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower 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 with reference to the accompanying drawings and specific implementation methods.

[0026] A reaction chamber, referring to Figure 2 and Figure 3 , used to accommodate battery silicon wafers and 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] Outer cavity 100, reference Figure 2 , which is the basic housing of the device. The outer chamber 100 is constructed with a reaction chamber that can accommodate process gases. The process gases form a reaction zone 700 within the reaction chamber to coat the solar cell silicon wafers within the reaction zone 700. Regarding the relationship between the solar cell silicon wafers and the reaction zone 700, the solar cell silicon wafers can be directly arranged in the reaction zone 700 to maximize the heating effect of the heating element 200 on the solar cell silicon wafers. Alternatively, a carrier can be used as a positioning tool for the solar cell silicon wafers to ensure that the solar cell silicon wafers are stably placed in the reaction zone 700, facilitating the convenient placement and removal of large numbers of solar cell silicon wafers.

[0028] For example, a long, rectangular carrier is designed to evenly accommodate the cell wafers. The wafers are aligned in the same direction within the carrier, allowing the process gas to flow toward the wafers at the same angle. If all the cell wafers are arranged vertically on the carrier, the process gas can flow from top to bottom across the surface of the cell wafers.

[0029] Furthermore, it is understood that the outer chamber 100 is provided with an inlet 500 and an outlet 600 for process gas flow in and out. The inlet 500 and outlet 600 are located at the upper and lower sides of the height direction of the reaction zone 700, and the inlet 500 and outlet 600 are respectively connected to the outer chamber 100 to achieve the flow of process gas from top to bottom or from bottom to top. The vertical arrangement of the inlet 500 and outlet 600 shortens the flow path of the process gas within the reaction zone 700, thereby improving the utilization rate of the process gas and the response efficiency of the coating. 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 part 710 at the upper part of the reaction zone 700, where the process gas distribution is not uniform or the mixing between multiple process gases is not uniform; and to avoid the battery silicon wafer being located in the second reaction part 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 positioned within the reaction chamber to heat the solar cell silicon wafers within the reaction zone 700. Common heating elements 200 are heating wires that generate heat through the application of an electric current. It is understood that the heating element 200 is positioned close to the inner wall of the reaction chamber, leaving ample space in the reaction chamber after the heating element 200 is installed, facilitating the design of 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, thereby reducing the volume of the reaction chamber. The air curtain unit 300 forms an air curtain 310 in the reaction chamber by the air entering and exiting 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. The faster the flow rate of the protective gas constituting the air curtain 310, the better the isolation effect of the 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] To increase the isolation range of the air curtain unit 300, it is understood that the air curtain 310 contacts the inner wall of the reaction chamber, i.e., the two types of barriers are combined to expand the restricted range, thereby limiting the range of the reaction zone 700; alternatively, multiple air curtain units 300 are provided, and the air curtains 310 between adjacent air curtain units 300 are combined with each other to form a larger gas barrier, thereby limiting the range of the reaction zone 700. Conventionally, two air curtain units 300 are provided, and the two air curtain units 300 are respectively arranged in the circumference of the reaction zone 700, so that the air curtains 310 are arranged in a circumferential direction of the reaction zone 700, isolating the reaction zone 700 to a local position in the reaction chamber.

[0033] For example, the reaction chamber is in the shape of an elongated strip, and the reaction zone 700 is preferably also designed in the shape of an elongated 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. Therefore, two air curtain units 300 are provided on either side of the width of the reaction zone 700 to limit the expansion of the reaction zone 700 in the width direction. To further restrict the reaction zone 700, in combination with the aforementioned barrier combination logic, the two air curtains 310 can contact the inner walls of the reaction chamber on both sides in the length direction to form a blockade of the reaction zone 700 in the width and length directions; or the two air curtains 310 can contact the inner walls of the reaction chamber on both sides in the height direction to form a blockade of the reaction zone 700 in the width and height directions. Similarly, the two air curtains 310 can simultaneously contact the inner walls of the reaction chamber on multiple sides 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 exposed to 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. 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 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] It is understandable that the various components in the present application are arranged based on the direction of movement of the process gas. The drawings of the specific embodiment of the present application illustrate that the process gas moves from top to bottom to form the air curtain 310, but the protection scope of the present application obviously also includes the process gas entering from bottom to top, from left to right, from right to left, from front to back, and from back to front. Of course, in addition to the aforementioned process gas entering from a certain positive direction and then exiting from another relative positive direction, the protection scope of the present application also includes the process gas entering from an oblique direction and exiting from an oblique direction, entering from an oblique direction and exiting from a positive direction, and entering from a positive direction and exiting from an oblique direction. The aforementioned oblique direction can be any direction, and the positive direction can also be any direction. In addition, when the movement direction of the aforementioned process gas changes, the position layout of the relative components is also adaptively adjusted accordingly. For example, if the process gas is introduced from front to back, the air curtain inlet 320 and the air curtain outlet 330 are arranged front to back, and the workstation 400 for accommodating the battery silicon wafers is located between the air curtain inlet 320 and the air curtain outlet 330 .

[0036] 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 separately; and the air curtain outlet 330 and the air outlet 600 on the outer cavity 100 have two design structures.

[0037] 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 merged, leaving only one air outlet 600 located below the reaction zone 700. This outlet 600 is used to output process gas and also draws the air curtain 310 located outside the reaction zone 700 toward the outlet 600, allowing the protective gas comprising the air curtain 310 to be discharged from the outlet 600. It should be noted that this structural form facilitates positioning the lower portion of the air curtain 310 closer to the reaction zone 700, thereby reducing the volume of the second reaction section 720 of the reaction zone 700 without affecting the normal coating of the solar cell silicon wafers, thereby reducing the external dimensions of the entire reaction chamber. It should be noted that, based on the aforementioned process that the lower part of the air curtain 310 needs to be close to the second reaction part 720, it means that the lower part of the air curtain 310 needs a space close to the second reaction part 720, so there needs to be a distance between the work station 400 in the reaction area 700 that accommodates the carrier or directly accommodates the battery silicon wafer 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.

[0038] Specifically, the gas outlet 600 can be located between the two gas curtain units 300. This allows the two gas curtains 310 to be brought closer together, reducing the volume of the lower portion of the reaction zone 700 in the vertical direction. This 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, reducing contact between the process gas and the inner wall of the reaction chamber. Only the upper interior of the reaction zone 700 is exposed to the process gas, facilitating subsequent maintenance. It is important to emphasize that after the shielding gas and process gas are output from the same gas outlet 600, they can be separated again during the process, allowing the shielding gas to be recycled.

[0039] 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 air outlet 600 of the reaction zone 700 are divided into two sets, which are independent and spaced apart. With this 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 between 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 set to flow vertically from top to bottom along the battery wafer in the reaction chamber.

[0040] A coating process method suitable for the above-mentioned reaction chamber is specifically as follows: starting the heating element 200 to heat the solar cell 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.

[0041] It should be noted that the order of heating the cell silicon wafer and establishing the air curtain 310 can be reversed. That is, the air curtain 310 can be established first, followed by heating the cell silicon wafer using the heating element 200. Furthermore, after stopping the flow of process gas into the reaction zone 700, the reaction chamber can be maintained in operation for a period of time, until the process gas in the reaction zone 700 is completely exhausted, before stopping the flow of the protective gas with an initial velocity into the air curtain unit 300. Whether the process gas has been exhausted can be determined by detecting whether the gas discharged from the gas outlet 600 contains process gas. Alternatively, the time for maintaining the reaction chamber in operation can be determined empirically.

[0042] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional 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.

[0043] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A reaction chamber for accommodating battery silicon wafers and 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 solar cell silicon wafer in the reaction zone (700); A heating element (200), the heating element (200) being arranged in the reaction chamber, the heating element 200 being arranged close to the inner wall of the reaction chamber, and being used for heating the cell silicon wafer in the reaction zone (700); and An air curtain unit (300) is provided, wherein the air curtain unit (300) forms an air curtain (310) in the reaction chamber by passing gas in and out of the reaction chamber, and the air curtain unit (300) is located between the heating element (200) and the reaction zone (700); wherein the air curtain (310) is provided 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, wherein The air curtain (310) contacts the inner wall of the reaction chamber to limit the range of the reaction zone (700); or, a plurality of air curtain units (300) are provided, and the air curtains (310) between adjacent air curtain units (300) are combined with each other to limit the range of the reaction zone (700).

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

4. The reaction chamber according to claim 3, wherein: The two air curtain units (300) are respectively arranged 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.

5. The reaction chamber according to claim 3, wherein: The reaction chamber further comprises an air inlet (500) and an air outlet (600) for the inlet and outlet of process gas, wherein 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 on the upper and lower sides of the height direction of the reaction zone (700).

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

7. The reaction chamber according to claim 6, wherein: The gas outlet (600) is located between the two gas curtain units (300), and the gas outlet (600) allows the two gas curtains (310) to be closer to each other, thereby reducing the volume of the lower part of the reaction zone (700) in the height direction.

8. The reaction chamber according to claim 1, wherein: 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 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 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, wherein: 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 method, characterized in that: Using the reaction chamber according to any one of claims 1 to 9, comprising: activating 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), a process gas is introduced 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 air curtain unit (300).

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