Copper electroplating heterojunction cell and physical vapor deposition equipment
By forming a copper-nickel alloy layer on the surface of the copper seed layer, the problem of excess plating material loss in copper electroplated heterojunction cells is solved, achieving cost reduction and efficiency improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TONGWEI SOLAR ENERGY (CHENGDU) CO LID
- Filing Date
- 2025-05-23
- Publication Date
- 2026-05-15
Smart Images
Figure CN224250104U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of solar cell technology, and more specifically, to a copper electroplated heterojunction cell and a physical vapor deposition apparatus. Background Technology
[0002] In the fabrication of heterojunction solar cells, related technologies use copper interconnect technology to replace the screen-printed silver grid lines. The copper interconnect technology involves first depositing a seed layer of copper on an ITO (TCO) conductive film by PVD sputtering for conductivity (as a seed layer for electroplating), then performing pattern transfer on this conductive layer, and finally electroplating the grid lines. Furthermore, a tin protective layer can be formed on the electroplated copper grid lines using chemical tin plating.
[0003] However, the copper-plated heterojunction solar cells provided by the related technology have excessive copper plating filling losses during grid line fabrication, which leads to increased plating costs. Utility Model Content
[0004] The purpose of this invention is to provide a copper electroplated heterojunction battery and a physical vapor deposition (PVD) apparatus. The PVD apparatus can be used to prepare copper electroplated heterojunction batteries. When forming grid lines, the copper electroplated heterojunction battery can reduce excess electroplating material loss, which helps to reduce costs.
[0005] The embodiments of this utility model can be implemented as follows:
[0006] In a first aspect, this utility model provides a copper electroplated heterojunction battery, comprising:
[0007] Yellow membrane, which includes a copper seed layer;
[0008] A copper-nickel alloy layer is deposited on the surface of the copper seed layer; and,
[0009] The gate lines are deposited on a copper-nickel alloy layer.
[0010] In an optional implementation, the cross-section of the grid lines is rectangular.
[0011] In an optional embodiment, the copper-plated heterojunction cell includes a plurality of grid lines with a groove between adjacent grid lines.
[0012] In an optional implementation, the groove has a rectangular cross-section.
[0013] In an optional embodiment, the yellow film further includes a silicon substrate, a first intrinsic amorphous silicon layer, a second intrinsic amorphous silicon layer, a first doped layer, a second doped layer, a first transparent conductive layer, and a second transparent conductive layer; wherein,
[0014] The silicon substrate includes a first surface and a second surface that are arranged opposite to each other;
[0015] A first intrinsic amorphous silicon layer is formed on the first surface; a second intrinsic amorphous silicon layer is formed on the second surface; a first doped layer is formed on the side of the first intrinsic amorphous silicon layer facing away from the silicon substrate; a second doped layer is formed on the side of the second intrinsic amorphous silicon layer facing away from the silicon substrate; a first transparent conductive layer is formed on the side of the first doped layer facing away from the first intrinsic amorphous silicon layer; and a second transparent conductive layer is formed on the side of the second doped layer facing away from the second intrinsic amorphous silicon layer.
[0016] Both the first transparent conductive layer and the second transparent conductive layer have copper seed layers formed thereon; at least one of the copper seed layers on the first transparent conductive layer and the second transparent conductive layer has a copper-nickel alloy layer formed thereon.
[0017] In an optional embodiment, both the copper seed layer on the first transparent conductive layer and the copper seed layer on the second transparent conductive layer are formed with a copper-nickel alloy layer.
[0018] In an optional implementation, the gate lines are copper gate lines.
[0019] In an optional embodiment, the copper-plated heterojunction cell further includes a protective layer formed on the side of the grid lines opposite to the copper-nickel alloy layer.
[0020] In an optional implementation, the protective layer is a tin protective layer.
[0021] Secondly, this utility model provides a physical vapor deposition apparatus for preparing a copper-nickel alloy layer of a copper electroplated heterojunction battery according to any of the foregoing embodiments; the physical vapor deposition apparatus has a deposition chamber in which a copper-nickel alloy target is disposed.
[0022] The beneficial effects of the copper electroplated heterojunction battery provided by this utility model embodiment include: the copper electroplated heterojunction battery forms a copper-nickel alloy layer in the copper seed layer, so that the photosensitive emulsion can be coated on the copper-nickel alloy layer during the preparation of the copper electroplated heterojunction battery. The copper-nickel alloy layer can increase the light reflectivity of the seed layer surface and improve the corrosion resistance of the seed layer surface in subsequent development and exposure processes. Since the reflectivity of the seed layer is increased, it is beneficial to improve the reflection of light during the exposure process, and the bottom of the photosensitive emulsion layer can be exposed again through the reflection of light, which enhances the cross-linking reaction of the photosensitive emulsion. As a result, there is no undercut small feature structure in the photosensitive emulsion after development, so that the cross-section of the pre-plated groove formed on the photosensitive emulsion after development is rectangular. After cleaning the unexposed part of the photosensitive emulsion, a groove with a rectangular cross-section can be formed, which is beneficial to reduce the loss of excess electroplating material when forming grid lines in the groove, and helps to reduce costs.
[0023] Moreover, the copper-nickel alloy layer can provide high hardness and wear resistance, further enhancing the adhesion of subsequent processes.
[0024] The beneficial effects of the physical vapor deposition equipment provided in this embodiment of the present invention include: the physical vapor deposition equipment can form a copper-nickel alloy layer on the surface of the copper seed layer of the yellow film by using a copper-nickel alloy target material set in the deposition chamber, thereby reducing the loss of excess electroplating material in the subsequent grid line fabrication process and helping to reduce costs. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of the pre-coated groove formed by the photosensitive adhesive layer in related technologies;
[0027] Figure 2 This is a schematic diagram of the structure of the copper electroplated heterojunction battery in an embodiment of this utility model;
[0028] Figure 3 This is a schematic diagram of the pre-plated groove formed by the photosensitive adhesive layer in an embodiment of this utility model.
[0029] Icons: 010 - Copper-plated heterojunction solar cell; 100 - Yellow film; 110 - Silicon substrate; 121 - First intrinsic amorphous silicon layer; 122 - Second intrinsic amorphous silicon layer; 131 - First doped layer; 132 - Second doped layer; 141 - First transparent conductive layer; 142 - Second transparent conductive layer; 150 - Copper seed layer; 160 - Copper-nickel alloy layer; 170 - Grid line; 180 - Protective layer; 200 - Photosensitive adhesive layer; 210 - Pre-plated groove. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0033] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0034] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.
[0035] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.
[0036] The related technologies provide methods for fabricating copper electroplated heterojunction solar cells, including:
[0037] 1. Cleaning and texturing, for example: using an etching solution to etch a silicon substrate to form a pyramidal textured surface, thereby improving surface utilization;
[0038] 2. Phase vapor deposition (PECVD): An amorphous silicon layer is deposited onto the textured surface to prepare a substrate for forming a PN junction. Specifically, a first intrinsic amorphous silicon layer and a second intrinsic amorphous silicon layer are formed on the first and second sides of the silicon substrate, respectively, opposite to each other. A first doped layer is formed on the first intrinsic amorphous silicon layer, and a second doped layer is formed on the second intrinsic amorphous silicon layer. In other words, a PN junction is formed on the first intrinsic amorphous silicon layer and the second intrinsic amorphous silicon layer, respectively.
[0039] 3. TCO film preparation (PVD / RPD): After the PN junction is formed, a conductive transparent thin film (ITO layer) is formed on its surface;
[0040] 4. Deposit seed layer (PVD-Cu): Due to the poor conductivity of TCO and the poor adhesion between electroplated copper and TCO, a highly conductive copper seed layer is formed by pretreatment on the TCO film.
[0041] 5. Coating: Apply a layer of negative photosensitive adhesive (as an electroplating mask) to the front and back of the yellow film (the semi-finished battery cell after copper seed layer deposition).
[0042] 6. Printing: Using a light source with a wavelength greater than 400nm to expose the non-grid lines, the mask induces cross-linking reactions, etc., causing the exposed parts to denature and become less susceptible to corrosion by weak alkaline solutions after deformation.
[0043] 7. Development: Use a 10g / L Na2CO3 solution to rinse the mask at 30℃ for 40s to clean the unexposed reaction areas of the mask and form pre-plated grooves.
[0044] 8. Edge wrapping: Use edge wrapping adhesive to wrap the sides of the yellow film to prevent the sides of the yellow film from being electroplated with copper metal, which would cause the front and back of the battery cell to be connected.
[0045] 9. Electroplating, utilizing the Cu in the electroplating solution 2+ The principle is that electrons migrate to the surface of the PVD copper seed layer with the help of the electric field, capture electrons, and deposit and fill the grooves after development;
[0046] 10. Remove the film and etch back. Use a strong alkaline solution to dissolve the residual photosensitive adhesive (i.e., mask adhesive) and edge-sealing adhesive, and use a strong oxidizing acid solution to etch the PVD-copper seed layer until the ITO layer is exposed.
[0047] 11. Light injection, using infrared light to repair Si-H bonds, internal defects in saturated heterojunction cells, and release internal stress in silicon wafers and coatings through high-temperature annealing;
[0048] 12. Tinning: This process uses chemical solutions to replace elemental Cu on the surface of copper grid lines, forming a tin layer on the surface of the copper grid lines to protect them from oxidation by air.
[0049] During processes 6 and 7, the light intensity at the bottom of the photosensitive emulsion is weaker than that at the surface during exposure (the g-line wavelength is 436 nm and the i-line wavelength is 365 nm during the exposure process; the reflectivity of the copper seed layer is low in the 300-400 nm wavelength range, around 20%-40%, and in the 400-500 nm wavelength range, the reflectivity is 40%-60%). The surface of the photosensitive emulsion is fully exposed, while the bottom is underexposed. This results in the pre-plated groove 210 on the photosensitive emulsion layer 200 exhibiting a trapezoidal cross-section after development (e.g., ...). Figure 1As shown in the diagram, during the subsequent electroplating process 9, more copper needs to be filled into the trapezoidal groove, which leads to excess copper filling loss and increases the cost of the electroplating solution. Because the pre-plating groove 210 has a trapezoidal cross-sectional shape, a larger filling volume is required during electroplating. At the same current density, the electroplating production time increases, and production capacity is somewhat affected.
[0050] Furthermore, the trapezoidal cross-sectional shape of the pre-plated groove 210 will also cause the solar cell to have an excess light-blocking area. That is, the grid lines formed by the pre-plated groove 210 will cause the solar cell to have an excess light-blocking area, resulting in an excess light-blocking area in the finished solar cell, affecting the light-receiving area, reducing Isc and affecting efficiency.
[0051] Please refer to Figure 2 and Figure 3 This embodiment provides a copper electroplated heterojunction battery 010, which can improve the above-mentioned problems.
[0052] The copper electroplated heterojunction solar cell 010 includes a yellow film 100, a copper-nickel alloy layer 160, and grid lines 170. The yellow film 100 includes a copper seed layer 150. The copper-nickel alloy layer 160 is deposited on the surface of the copper seed layer 150. The grid lines 170 are deposited on the copper-nickel alloy layer 160.
[0053] The copper-plated heterojunction solar cell 010 has a copper-nickel alloy layer 160 formed in the copper seed layer 150. This allows for the application of photosensitive adhesive onto the copper-nickel alloy layer 160 during the fabrication of the cell. The copper-nickel alloy layer 160 can increase the light reflectivity of the seed layer surface during subsequent development and exposure processes (the reflectivity of the copper-nickel alloy layer 160 can reach approximately 40%-60% in the 300-400nm wavelength range; and in the 400-500nm wavelength range, the reflectivity of the copper-nickel alloy layer 160 can reach approximately 40%-60%). The reflectivity of the seed layer is around 60%-70%, which improves the corrosion resistance of the seed layer surface. Because the reflectivity of the seed layer is increased, it is beneficial to improve light reflection during exposure, and through light reflection, a secondary exposure process is achieved on the bottom of the photosensitive emulsion layer 200, enhancing the cross-linking reaction of the photosensitive emulsion. This results in the absence of undercut features in the photosensitive emulsion after development, ensuring that the cross-section of the pre-plated groove 210 formed on the photosensitive emulsion after development has a rectangular shape (e.g., ...). Figure 3As shown, after cleaning the unexposed portion of the photosensitive emulsion, a rectangular groove is formed. This reduces excess electroplating material loss during the formation of the grid lines 170 within the groove, thus lowering costs. Furthermore, the copper-nickel alloy layer 160 provides higher hardness and wear resistance, further enhancing the adhesion of subsequent processes. Simultaneously, because the pre-plating groove 210 has a rectangular cross-sectional shape, the filling volume is correspondingly reduced during electroplating. At the same current density, the electroplating production time is shortened, leading to increased production capacity.
[0054] Furthermore, the cross-section of the grid line 170 is rectangular. This helps to reduce the light-shielding area of the finished solar cell, increase the light-receiving area, increase Isc, and improve efficiency.
[0055] Optionally, the copper-plated heterojunction solar cell 010 includes multiple grid lines 170, with a groove between two adjacent grid lines 170; the groove has a rectangular cross-section. This further ensures a neat structure with clean sides for the grid lines 170, reducing excess light-shielding area on the solar cell.
[0056] Optionally, the structure of the yellow film 100 is similar to that of related technologies, and it further includes a silicon substrate 110, a first intrinsic amorphous silicon layer 121, a second intrinsic amorphous silicon layer 122, a first doped layer 131, a second doped layer 132, a first transparent conductive layer 141, and a second transparent conductive layer 142; wherein, the silicon substrate 110 includes a first surface and a second surface distributed opposite to each other; the first intrinsic amorphous silicon layer 121 is formed on the first surface; the second intrinsic amorphous silicon layer 122 is formed on the second surface; the first doped layer 131 is formed on the side of the first intrinsic amorphous silicon layer 121 away from the silicon substrate 110; the second doped layer 131... 32 is formed on the side of the second intrinsic amorphous silicon layer 122 away from the silicon substrate 110; the first transparent conductive layer 141 is formed on the side of the first doped layer 131 away from the first intrinsic amorphous silicon layer 121, and the second transparent conductive layer 142 is formed on the side of the second doped layer 132 away from the second intrinsic amorphous silicon layer 122; both the first transparent conductive layer 141 and the second transparent conductive layer 142 have copper seed layers 150 formed thereon; at least one of the copper seed layers 150 on the first transparent conductive layer 141 and the second transparent conductive layer 142 has a copper-nickel alloy layer 160 formed thereon.
[0057] Furthermore, both the copper seed layer 150 on the first transparent conductive layer 141 and the copper seed layer 150 on the second transparent conductive layer 142 are formed with a copper-nickel alloy layer 160; and the gate line 170 is a copper gate line.
[0058] Furthermore, the copper-plated heterojunction solar cell 010 also includes a protective layer 180, which is formed on the side of the grid line 170 away from the copper-nickel alloy layer 160, and the protective layer 180 can be a tin protective layer.
[0059] This embodiment also provides a physical vapor deposition apparatus for preparing a copper-nickel alloy layer 160 of a copper electroplated heterojunction battery 010; the physical vapor deposition apparatus has a deposition chamber in which a copper-nickel alloy target is disposed.
[0060] In summary, the physical vapor deposition equipment of this invention can be used to prepare copper electroplated heterojunction solar cells 010. When forming the grid lines 170, the copper electroplated heterojunction solar cells 010 can reduce the loss of excess electroplating material, which is beneficial to reducing costs.
[0061] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.
Claims
1. A copper-plated heterojunction battery, characterized in that, include: A yellow membrane (100), the yellow membrane (100) comprising a copper seed layer (150); A copper-nickel alloy layer (160) is deposited on the surface of the copper seed layer (150); and, Gate line (170), which is deposited on the copper-nickel alloy layer (160).
2. The copper-plated heterojunction battery according to claim 1, characterized in that, The cross-section of the grid line (170) is rectangular.
3. The copper-plated heterojunction battery according to claim 1, characterized in that, The copper-plated heterojunction cell includes a plurality of grid lines (170), with a groove between two adjacent grid lines (170).
4. The copper-plated heterojunction battery according to claim 3, characterized in that, The groove has a rectangular cross-section.
5. The copper-plated heterojunction battery according to claim 1, characterized in that, The yellow film (100) further includes a silicon substrate (110), a first intrinsic amorphous silicon layer (121), a second intrinsic amorphous silicon layer (122), a first doped layer (131), a second doped layer (132), a first transparent conductive layer (141), and a second transparent conductive layer (142); wherein, The silicon substrate (110) includes a first surface and a second surface that are opposite to each other; The first intrinsic amorphous silicon layer (121) is formed on the first surface; the second intrinsic amorphous silicon layer (122) is formed on the second surface; the first doped layer (131) is formed on the side of the first intrinsic amorphous silicon layer (121) away from the silicon substrate (110); the second doped layer (132) is formed on the side of the second intrinsic amorphous silicon layer (122) away from the silicon substrate (110); the first transparent conductive layer (141) is formed on the side of the first doped layer (131) away from the first intrinsic amorphous silicon layer (121), and the second transparent conductive layer (142) is formed on the side of the second doped layer (132) away from the second intrinsic amorphous silicon layer (122); Both the first transparent conductive layer (141) and the second transparent conductive layer (142) are formed with the copper seed layer (150); at least one of the copper seed layer (150) on the first transparent conductive layer (141) and the copper seed layer (150) on the second transparent conductive layer (142) is formed with the copper-nickel alloy layer (160).
6. The copper-plated heterojunction battery according to claim 5, characterized in that, Both the copper seed layer (150) on the first transparent conductive layer (141) and the copper seed layer (150) on the second transparent conductive layer (142) have the copper-nickel alloy layer (160) formed thereon.
7. The copper-plated heterojunction battery according to any one of claims 1-6, characterized in that, The gate line (170) is a copper gate line.
8. The copper-plated heterojunction battery according to any one of claims 1-6, characterized in that, The copper-plated heterojunction cell further includes a protective layer (180) formed on the side of the grid line (170) opposite to the copper-nickel alloy layer (160).
9. The copper-plated heterojunction battery according to claim 8, characterized in that, The protective layer (180) is a tin protective layer.
10. A physical vapor deposition apparatus, characterized in that, The copper-nickel alloy layer (160) for preparing the copper electroplated heterojunction cell according to any one of claims 1-9; the physical vapor deposition apparatus has a deposition chamber in which a copper-nickel alloy target is disposed.