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 coating equipment, and in particular to a reaction chamber and a 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, and the alumina thin film prepared by ALD is recognized by the industry as the best method for preparing thin films with high quality.

[0003] Currently, the reaction chamber of an ALD device consists of an inner cavity and an outer cavity. The structure of the reaction chamber is as shown in the attached... Figure 1 When the temperature of the battery silicon wafers in the carrier reaches the process required temperature, the thin film deposition process can be carried out. During the entire heating process, the heating elements attached to the outer cavity wall first heat the inner cavity and then heat the carrier to make the battery silicon wafers reach the temperature requirement. When the reaction chamber reaches the process requirements, trimethylaluminum (TMA) and water (H2O) are introduced into the reaction chamber, and a dense alumina thin film is deposited on the crystal surface, thereby achieving the purpose of passivating the surface of crystalline silicon.

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

[0005] Therefore, the technical problem of the existing technology is: how to improve the heating efficiency of the reaction chamber for battery silicon wafers. Summary of the Invention

[0006] The embodiments of the present application provide a reaction chamber, which solves the technical problem of how to improve the heating efficiency of the reaction chamber for battery silicon wafers in the existing technology; and achieves the improvement of the heating efficiency of the reaction chamber for battery silicon wafers.

[0007] The embodiments of the present application provide a reaction chamber for accommodating battery silicon wafers and coating the battery silicon wafers by inputting process gases. The reaction chamber includes: an outer cavity, which constructs a reaction chamber capable of accommodating process gases, and the process gases form a reaction zone in the reaction chamber to coat the battery silicon wafers in the reaction zone; heating elements, which are arranged in the reaction chamber for heating the battery silicon wafers in the reaction zone; and an air curtain unit, which forms an air curtain in the reaction chamber by flowing in and out of gases in the reaction chamber, wherein the air curtain is arranged outside the reaction zone to limit the range of the reaction zone in the reaction chamber.

[0008] Preferably, the air curtain contacts the inner wall of the reaction chamber to limit the range of the reaction zone; alternatively, 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 respectively arranged in the circumferential direction of the reaction zone, so that the formed air curtain is arranged in the circumferential direction of the reaction zone.

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

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

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

[0013] Preferably, the air outlet is located in the middle of the two air curtain units. Through the air outlet, the two air curtains are made to approach each other 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 air inlet and an air curtain air outlet. The air curtain air inlet and the air curtain air outlet pass through the outer cavity and are communicated in the reaction chamber; wherein, flow equalizing plates are arranged at the output end of the air curtain air inlet and the input end of the air curtain air outlet, and the two flow equalizing plates make the air curtain unit form an air curtain.

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

[0016] A coating process method includes: 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 to establish the air curtain by the air curtain unit; after the air curtain unit establishes the air curtain, introducing the 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] One or more of the above technical solutions in the embodiments of the present application have at least one or more of the following technical effects: 1. In this application, the air curtain unit is used to replace the inner cavity. The advantages are as follows: First, the air curtain formed by the air curtain unit can isolate the dust generated by the reaction, still having the dust isolation function of the inner cavity. Second, the heating element can directly heat the battery silicon wafer in the reaction zone across the air curtain, avoiding the need to first heat the inner cavity in the conventional reaction chamber structure, with fast heating and low heating energy consumption. It solves the technical problem of how to improve the heating efficiency of the reaction chamber for the battery silicon wafer in the prior art; achieving an improvement in the heating efficiency of the reaction chamber for the battery silicon wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic cross-sectional structure view in the main viewing direction of the existing reaction chamber; Figure 2 is a schematic cross-sectional structure view in the main viewing direction of a reaction chamber Figure 1 ; Figure 3 is a schematic cross-sectional structure view in the main viewing direction of a reaction chamber Figure 2 .

[0019] Reference numerals: 100, outer cavity; 200, heating element; 300’, inner cavity; 300, air curtain unit; 310, air curtain; 320, air curtain inlet; 330, air curtain outlet; 400, work station; 500, inlet; 510, first inlet; 520, second inlet; 600, outlet; 700, reaction zone; 710, first reaction part; 720, second reaction part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The serial numbers assigned to the components in this article, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meanings. And the "connection" and "coupling" mentioned in this application, unless otherwise specified, both include direct and indirect connection (coupling). In the description of this application, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings, and are 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 should not be construed as a limitation to this application.

[0021] In this application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the 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, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0022] To better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0023] A reaction chamber, referring to Figure 2 and Figure 3 , is used to accommodate a battery silicon wafer and coat the battery silicon wafer by inputting process gas. 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 inside the outer cavity 100. The heating element 200 is used to heat the battery silicon wafer inside the outer cavity 100, and the air curtain unit 300 is used to form an air curtain 310 to limit the movement range of the process gas after entering the outer cavity 100.

[0024] The outer cavity 100, referring to Figure 2 , is the basic housing of a device. The outer cavity 100 is constructed with a reaction cavity that can accommodate process gas, and the process gas forms a reaction zone 700 inside the reaction cavity to coat the battery silicon wafer in the reaction zone 700; among them, regarding the relationship between the battery silicon wafer and the reaction zone 700, the battery silicon wafers can be directly arranged in the reaction zone 700, so that the heating effect of the heating element 200 on the battery silicon wafers is the best; 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 and also facilitate the convenient placement and removal of a large number of battery silicon wafers.

[0025] Exemplarily, a long strip-shaped carrier is designed to uniformly accommodate the battery silicon wafers, and the battery silicon wafers are arranged in the same direction in the carrier, so that the process gas can move towards the battery silicon wafers at the same angle. For example, if all the battery silicon wafers are arranged vertically on the carrier, the process gas can move from top to bottom across the surface of the battery silicon wafers.

[0026] In addition, it can be understood that an inlet 500 and an outlet 600 for process gas to enter and exit are provided on the outer cavity 100. The inlet 500 and the outlet 600 are located on the upper and lower sides in the height direction of the reaction zone 700, and the inlet 500 and the outlet 600 are respectively communicated with the outer cavity 100 to enable the process gas to move from top to bottom or from bottom to top. The above arrangement of the inlet 500 and the outlet 600 up and down makes the movement path of the process gas in the reaction zone 700 short, improving the utilization rate of the process gas and the response efficiency of film coating. Among them, it is preferably 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 situation that when the battery silicon wafer is located in the first reaction part 710 at the upper part of the reaction zone 700, the distribution of the process gas is not uniform enough or the mixing of multiple process gases is not uniform enough; and also to avoid the situation that when the battery silicon wafer is located in the second reaction part 720 at the lower part of the reaction zone 700, the outlet 600 will affect the flow rate and flow direction of the process gas.

[0027] The heating element 200, refer to Figure 2 , the heating element 200 is arranged in the reaction chamber and is used to heat the battery silicon wafer in the reaction zone 700. A common heating element 200 is a heating wire, which generates heat through an electric current. It can be understood that the heating element 200 is arranged close to the inner wall of the reaction chamber so that there is still a large space in the reaction chamber after the heating element 200 is arranged, which is convenient for designing the air curtain unit 300.

[0028] The air curtain unit 300, refer to Figure 2 , which is used to form a gas barrier to achieve zoning 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, reducing the volume of the reaction chamber. The air curtain unit 300 forms an air curtain 310 in the reaction chamber by allowing gas to enter and exit the reaction chamber. Among them, the air curtain 310 is arranged outside the reaction zone 700, and the range of the reaction zone 700 in the reaction chamber is restricted 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.

[0029] To increase 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 restricting 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, that is, combined into a larger gas barrier, thereby restricting the range of the reaction zone 700. Conventionally, two air curtain units 300 are provided, and the two air curtain units 300 are arranged on the circumferential direction of the reaction zone 700, so that the formed air curtain 310 is arranged on the circumferential direction of the reaction zone 700, isolating the reaction zone 700 at a local position in the reaction chamber.

[0030] Exemplarily, the reaction chamber is in a long strip shape, and based on the shape of the reaction chamber and the principle of maximizing utilization, the reaction zone 700 is preferably also designed in a long strip shape. In this case, the distance between the reaction zone 700 and the reaction chamber in the width direction is generally the largest. Then, the two air curtain units 300 are arranged on both sides of the reaction zone 700 in the width direction to restrict the expansion of the reaction zone 700 in the width direction of the reaction zone 700. To improve the restriction on the reaction zone 700, combined with the foregoing barrier combination logic, it can be that the two air curtains 310 contact the inner walls on both sides in the length direction of the reaction chamber to form a blockade of the reaction zone 700 in the width and length directions; it can also be that the two air curtains 310 contact the inner walls on both sides in the height direction of the reaction chamber to form a blockade of the reaction zone 700 in the width and height directions; similarly, the two air curtains 310 can contact the inner walls of the reaction chamber on multiple sides simultaneously to more comprehensively blockade the reaction zone 700. In addition, air curtain units 300 can be added to form air curtains 310 to replace the inner wall of the reaction chamber, which can more accurately restrict the range of the reaction zone 700 and also reduce the inner wall area in contact with dust during the reaction.

[0031] 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 communicate in the reaction chamber; wherein, flow equalizing plates (not shown in the figure) are provided at the output end of the air curtain air inlet 320 and the input end of the air curtain air outlet 330, and the two flow equalizing plates enable the air curtain unit 300 to form an air curtain 310.

[0032] It is understandable that each component in the present application is arranged based on the movement direction of the process gas. The drawings of the specific embodiments of the present application illustrate that the process gas moves from top to bottom to form the gas curtain 310. However, 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 above-mentioned schemes where the process gas enters from a certain positive direction and exits from the opposite 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. Exemplarily, if the process gas enters from front to back, the gas curtain inlet 320 and the gas curtain outlet 330 are arranged front and back, and the station 400 for accommodating the battery silicon wafer is located between the gas curtain inlet 320 and the gas curtain outlet 330.

[0033] Reference Figure 2 and Figure 3 , the gas curtain inlet 320 and the inlet 500 on the outer cavity 100 are independent of each other to respectively introduce gases; and the gas curtain outlet 330 and the outlet 600 on the outer cavity 100 have two design structures.

[0034] The first structure of the gas curtain outlet 330 and the outlet 600 on the outer cavity 100 is as follows: Reference Figure 2 , the gas curtain outlet 330 and the outlet 600 of the outer cavity 100 are combined, and only one outlet 600 located below the reaction zone 700 is retained. The outlet 600 is for the output of the process gas, and also attracts the gas curtain 310 located outside the reaction zone 700 to be close to the outlet 600, and makes the protective gas forming the gas curtain 310 also output from the outlet 600. It should be noted that this structural form is beneficial to making the lower part of the gas curtain 310 close to the reaction zone 700, which is beneficial to reducing the volume of the second reaction part 720 of the reaction zone 700 without affecting the normal coating of the battery silicon wafer, and then reducing the outer size of the entire reaction chamber. It should be noted that based on the aforementioned need for the lower part of the gas curtain 310 to have a process of approaching the second reaction part 720, it means that the lower part of the gas curtain 310 requires a space to approach the second reaction part 720. Then, there should be a spacing between the station 400 for accommodating the carrier or directly accommodating the battery silicon wafer in the reaction zone 700 and the outlet 600, and through this spacing, the protective gas forming the gas curtain 310 moves out from the outlet 600.

[0035] Specifically, the air outlet 600 is located in the middle of the two air curtain units 300. Through the air outlet 600, the two air curtains 310 are made to approach each other, so as 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 air curtains 310 are guided to form a U-shaped gas barrier, reducing the contact between the process gas and the inner wall of the reaction chamber. Only the upper part inside the reaction zone 700 is contacted by the process gas, making the later maintenance convenient. It should be emphasized that after the protective gas and the process gas are output from the same air outlet 600, they can be separated by process, and the protective gas can be recycled.

[0036] The second structure of the air curtain air outlet 330 and the air outlet 600 on the outer cavity 100 is as follows: Refer to Figure 3 , the air curtain air outlet 330 and the air outlet 600 of the reaction zone 700 are divided into two sets, and the two are independent and spaced apart. With such a design, the air curtain 310 has a first movement direction in the reaction chamber, while the process gas has a second movement direction in the reaction chamber. Preferably, the first movement direction and the second movement direction are the same or substantially the same, so that the air curtain 310 is close to the reaction zone 700, and the movements between the protective gas and the process gas do not interfere with each other. It should be noted that there is a preferred direction for the second movement direction of the process gas movement relative to the battery silicon wafer. Specifically, when the battery wafer is vertically arranged, the process gas preferably flows vertically downward along the battery wafer. In this case, the air curtain 310 in the reaction chamber is also preferably arranged to flow vertically downward along the battery wafer.

[0037] A coating process method applicable to the above reaction chamber is as follows. Specifically, start the heating element 200 to heat the battery silicon wafer in the reaction zone 700; introduce a protective gas with an initial velocity into the air curtain unit 300 to establish the air curtain 310 in the air curtain unit 300; after the air curtain 310 is established in the air curtain unit 300, introduce the process gas into the reaction zone 700 in the middle of the air curtain 310; after stopping introducing the process gas into the reaction zone 700, stop introducing the protective gas with an initial velocity into the air curtain unit 300.

[0038] It should be noted that the order of heating the battery silicon wafer and establishing the air curtain 310 can be interchanged, that is, the air curtain 310 can be established first, and then the battery silicon wafer can be heated by the heating element 200. In addition, after stopping introducing the process gas into the reaction zone 700, the reaction chamber can be maintained in operation for a period of time first. After all the process gas in the reaction zone 700 is exhausted, then before stopping introducing the protective gas with an initial velocity into the air curtain unit 300. Whether the process gas is exhausted can be determined by detecting whether the gas discharged from the air outlet 600 contains the process gas; it can also be determined by relying on experience to determine a time for maintaining the operation of the reaction chamber as described above.

[0039] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0040] 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 equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A reaction chamber for accommodating a battery silicon wafer and coating the battery silicon wafer by inputting process gases, characterized in that, The reaction chamber includes: An outer cavity (100), which is constructed with a reaction cavity capable of accommodating process gas, and the process gas forms a reaction zone (700) in the reaction cavity to coat the battery silicon wafers in the reaction zone (700); A heating element (200), which is arranged in the reaction cavity and is used to heat the battery silicon wafers in the reaction zone (700); and An air curtain unit (300), which forms an air curtain (310) in the reaction cavity by flowing gas in and out of the reaction cavity. Wherein, the air curtain (310) is arranged outside the reaction zone (700), and the range of the reaction zone (700) in the reaction cavity is restricted 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 cavity to restrict 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 restrict the range 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 respectively arranged in the circumferential direction of the reaction zone (700) so that the formed air curtain (310) is arranged in the circumferential direction of the reaction zone (700).

4. The reaction chamber according to claim 3, characterized in that, The two air curtain units (300) are respectively arranged on both sides in the width direction of the reaction zone (700) to restrict the expansion of the reaction zone (700) in its width direction.

5. The reaction chamber according to claim 3, characterized in that, The reaction chamber further includes 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 and communicatively arranged on the outer cavity (100), and the air inlet (500) and the air outlet (600) are located on the upper and lower sides in 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 air outlet (600).

7. The reaction chamber according to claim 6, wherein The air outlet (600) is located in the middle of the two air curtain units (300), and the two air curtains (310) are made to approach each other through the air 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, wherein 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) penetrate through the outer cavity (100) and communicate in the reaction cavity; wherein, flow equalizing plates are arranged at the output end of the air curtain air inlet (320) and the input end of the air curtain air outlet (330), 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 air intake and exhaust of the air curtain (310) and the air intake and exhaust of the reaction zone (700) are divided into two sets; the air curtain (310) has a first movement direction in the reaction cavity, and the process gas has a second movement direction in the reaction cavity. The first movement direction and the second movement direction are the same or basically the same.

10. A coating process method, 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 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 the 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 an initial velocity into the air curtain unit (300).

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