Manufacturing method of solar cell

Abstract

The invention discloses a manufacturing method of a solar cell, relates to the technical field of photovoltaics, and is used for reducing the damage degree of a first semiconductor layer and / or a semiconductor substrate in a first laser irradiation area and improving the yield of the solar cell on the premise of realizing patterning treatment of a nitrogen-containing mask layer. And good working performance of the solar cell is facilitated. The manufacturing method of the solar cell comprises the following steps: firstly, sequentially forming a first semiconductor layer and a nitrogen-containing mask layer which are stacked on a semiconductor substrate; next, a partial region of the nitrogen-containing mask layer is irradiated with a first laser, so that the nitrogen content in the first laser irradiation region of the nitrogen-containing mask layer is reduced. And then, removing the nitrogen-containing mask layer in the first laser irradiation area by using a first corrosive liquid.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular, to a manufacturing method of a solar cell. Background Art

[0002] A solar cell is a device that can convert solar light energy into electrical energy. Specifically, when the solar cell is in a working state, sunlight shines on the semiconductor p-n junction of the solar cell, forming new hole-electron pairs. Under the action of the built-in electric field in the p-n junction, the photo-generated holes flow to the p region, and the photo-generated electrons flow to the n region. After connecting the circuit, an electric current can be generated. And patterning is an important step in the manufacturing process of solar cells. For example, operations such as opening a film on a semiconductor layer, isolating two types of semiconductor layers with opposite conductivity types in a back contact cell, and selectively grooving a passivation layer before metallization all require patterning.

[0003] However, when the existing manufacturing method of a solar cell performs patterning, it is easy to damage the semiconductor layer and / or the semiconductor substrate located below the patterning layer, thereby affecting the working performance of the solar cell. Summary of the Invention

[0004] The purpose of the present invention is to provide a manufacturing method of a solar cell, which can reduce the damage degree to the first semiconductor layer and / or the semiconductor substrate located in the first laser irradiation area on the premise of realizing the patterning of the nitrogen-containing mask layer, improve the yield of the solar cell, and is beneficial to the solar cell having good working performance.

[0005] To achieve the above purpose, the present invention provides a manufacturing method of a solar cell. The manufacturing method of the solar cell includes: First, a first semiconductor layer and a nitrogen-containing mask layer are sequentially formed on a semiconductor substrate in a stacked manner. Next, a part of the nitrogen-containing mask layer is irradiated with a first laser to reduce the nitrogen content in the first laser irradiation area of the nitrogen-containing mask layer. Next, the nitrogen-containing mask layer located in the first laser irradiation area is removed by a first etching solution.

[0006] In the case of adopting the above technical solution, in the manufacturing method provided by the present invention, a part of the nitrogen-containing mask layer is irradiated with a first laser. During the irradiation with the first laser, the nitrogen-containing mask layer in the first laser irradiation area is heated, so that the nitrogen element therein volatilizes in the form of nitrogen gas. Furthermore, in the nitrogen-containing mask layer after being irradiated with the first laser, the nitrogen content in the first laser irradiation area decreases, while the nitrogen content in the area not irradiated with the first laser remains unchanged, thereby realizing the modification treatment of part of the area in the nitrogen-containing mask layer. Based on this, different parts in different areas of the nitrogen-containing mask layer have different nitrogen contents, and the nitrogen-containing mask layer with a lower nitrogen content in the first laser irradiation area is removed by a first etching solution, thereby realizing the patterning treatment of the nitrogen-containing mask layer. It can be seen that in the manufacturing method provided by the present invention, only the nitrogen content in part of the nitrogen-containing mask layer is reduced by the first laser irradiation method, and then by the wet etching method, the nitrogen-containing mask layer in the first laser irradiation area is removed by the first etching solution, rather than directly heating the nitrogen-containing mask layer to be removed by high-temperature laser to cause film explosion in the laser irradiation area corresponding to the nitrogen-containing mask layer. Therefore, the degree of thermal damage to the part of the semiconductor substrate (or to the semiconductor substrate and the first semiconductor layer) below the nitrogen-containing mask layer in the first laser irradiation area can be reduced, the yield of the solar cell can be improved, and it is beneficial for the manufactured solar cell to have good working performance.

[0007] As a possible implementation solution, in the nitrogen-containing mask layer, the corrosion resistance of the part in the first laser irradiation area to the first etching solution is less than that of the remaining part to the first etching solution. In this case, at least the etching rate difference between the part of the nitrogen-containing mask layer irradiated with the first laser and the part not irradiated with the first laser can be utilized to realize the selective etching of the nitrogen-containing mask layer in the first laser irradiation area, reduce the influence of the first etching solution on the part of the nitrogen-containing mask layer not irradiated with the first laser, improve the patterning treatment accuracy, and further improve the yield of the manufactured solar cell.

[0008] As a possible implementation solution, the part of the nitrogen-containing mask layer in the first laser irradiation area is formed with a hole structure.

[0009] In the case of adopting the above technical solution, the existence of the hole structure makes the structure of the nitrogen-containing mask layer located in the first laser irradiation area looser, so that the first etchant can contact the inside of the nitrogen-containing mask layer located in the first laser irradiation area through the hole structure, increasing the etching area and etching rate of the first etchant on the nitrogen-containing mask layer located in the first laser irradiation area, improving the patterning processing productivity, and at the same time facilitating further reducing the influence of the first etchant on the part of the nitrogen-containing mask layer not irradiated by the first laser, and improving the patterning processing accuracy. Or, the first etchant can etch the first semiconductor layer or other film layers (such as a surface passivation layer, etc.) disposed under the nitrogen-containing mask layer located in the first laser irradiation area through the hole structure, so as to remove the nitrogen-containing mask layer located in the first laser irradiation area by a stripping method, providing another example for the manufacturing method provided by the present invention and improving the applicability of the manufacturing method provided by the present invention in different application scenarios.

[0010] As a possible implementation solution, the maximum aperture of at least one hole structure is greater than or equal to 5 nm and less than or equal to 20 μm.

[0011] In the case of adopting the above technical solution, the hole structure is formed by irradiating a part of the nitrogen-containing mask layer with the first laser to partially remove the nitrogen-containing mask layer located in the first laser irradiation area by means of heat treatment. Specific removal methods may be, for example, thermal gasification, thermal film explosion, or heating to cause the nitrogen element in this part of the nitrogen-containing mask layer to volatilize in the form of nitrogen gas, thereby forming a hole structure on the nitrogen-containing mask layer. Based on this, it can be understood that the higher the power density of the first laser, the larger the aperture and / or the number of hole structures formed in the nitrogen-containing mask layer. On the contrary, the lower the power density of the first laser, the smaller the aperture and / or the number of hole structures formed in the nitrogen-containing mask layer. In this case, the maximum aperture of at least one hole structure being within the above range is conducive to preventing the etching rate of the first etchant for removing the nitrogen-containing mask layer located in the first laser irradiation area from being too low due to the too small maximum aperture of the hole structure, and is conducive to improving the manufacturing efficiency. In addition, it can also prevent the irradiation temperature of the first laser on the nitrogen-containing mask layer from being too high due to the too large size of the hole structure, further reducing the degree of thermal damage to the semiconductor substrate after patterning processing, improving the yield of the manufactured solar cell, and being beneficial to the good working performance of the solar cell.

[0012] As a possible implementation solution, at least one hole structure is a through hole penetrating the nitrogen-containing mask layer.

[0013] In the case of adopting the above technical solution, since the thickness of the nitrogen-containing mask layer is fixed, compared with a blind hole with an opening at one end and a closed end at the other end (i.e., the hole structure does not penetrate the nitrogen-containing mask layer), when at least one hole structure is a through hole penetrating the nitrogen-containing mask layer, the area of ​​the nitrogen-containing mask layer exposed by the hole structure increases, which is more conducive to the first etching liquid to quickly erode the nitrogen-containing mask layer located in the first laser irradiation area, and further increases the etching rate of the nitrogen-containing mask layer located in the first laser irradiation area by the first etching liquid. Alternatively, the first etching liquid can directly etch the first semiconductor layer or other film layer disposed under the nitrogen-containing mask layer located in the first laser irradiation area through the hole structure, without having to etch through the hole structure to contact the first semiconductor layer or other film layer, further improving the rate of removing the nitrogen-containing mask layer located in the first laser irradiation area, and improving the efficiency and production capacity of the patterning process.

[0014] As a possible implementation scheme, in at least one hole structure, a size of a hole opening on a side away from the first semiconductor layer is smaller than a size of a hole bottom on a side close to the first semiconductor layer.

[0015] In the case of adopting the above technical solution, the size of the hole bottom of the hole structure is relatively large, which is conducive to the accumulation of the corresponding etching liquid at the hole bottom of the hole structure, enhancing the etching rate of the etching liquid at the corresponding hole bottom portion of the nitrogen-containing passivation layer, and improving the rate of removing the nitrogen-containing mask layer located in the first laser irradiation area. In addition, if the manufacturing method provided by the present invention is adopted to obtain a conductive contact area for filling the first electrode by removing the nitrogen-containing mask layer in the first laser irradiation area, the size of the hole bottom of the hole structure is relatively large, which is conducive to making the size of the first electrode set at the hole bottom of the hole structure relatively large, which is conducive to having a larger contact area between the first electrode and the first semiconductor layer, and reducing the contact resistance between the two. The hole size of the hole structure on the side away from the first semiconductor layer is relatively small, which is conducive to enhancing the adhesion between the first electrode and the nitrogen-containing mask layer located in the first laser irradiation area, reducing the risk of the first electrode falling off from the nitrogen-containing mask layer, enhancing the contact performance and contact strength between the first electrode and the first semiconductor layer, and improving the yield of the manufactured solar cell.

[0016] As a possible implementation scheme, at least one hole structure is cylindrical, bowl-like or gourd-like. In this case, the morphology of the hole structure has multiple examples, which is conducive to improving the applicability of the method for manufacturing a solar cell provided by the present invention in different practical application environments. In addition, it is also conducive to reducing the difficulty of the manufacturing process of forming a hole structure in the nitrogen-containing mask layer located in the first laser irradiation area.

[0017] As a possible implementation solution, removing the nitrogen-containing mask layer located in the first laser irradiation area by using a first etching solution includes: removing the nitrogen-containing mask layer located in the first laser irradiation area and a first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation area. In this case, through the manufacturing method provided by the present invention, under the protection of the part of the nitrogen-containing mask layer that is not irradiated by the first laser, patterning of the first semiconductor layer can be achieved, the degree of thermal damage to the part of the semiconductor substrate corresponding to the first laser irradiation area after patterning can be reduced, and the yield of the manufactured solar cell can be improved.

[0018] As a possible implementation solution, after removing the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation area by using a first etching solution, the manufacturing method of the solar cell further includes: polishing and / or texturing the surface of the area where the semiconductor substrate is exposed outside the remaining nitrogen-containing mask layer by using the first etching solution.

[0019] In the case of adopting the above technical solution, after removing the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation area, under the protection of the nitrogen-containing mask layer that is not irradiated by the first laser, the surface of the area where the semiconductor substrate is exposed outside the remaining nitrogen-containing mask layer can be polished by using the first etching solution to improve the flatness of the surface of this area, which is beneficial to improving the formation quality and deposition film thickness of the film layer (such as surface passivation layer, antireflection layer, second semiconductor layer, etc.) formed on the surface of this area and improving the working performance of the solar cell. And texturing the surface of the area where the semiconductor substrate is exposed outside the remaining nitrogen-containing mask layer by using the first etching solution can improve the light trapping effect of the surface of this area, increase the utilization rate of incident light, and further improve the bifaciality of the manufactured solar cell. Or, the texturing treatment can increase the specific surface area of the second semiconductor layer formed on the surface of this area, increase the contact area between the second semiconductor layer and the corresponding conductive material, and reduce the contact resistance. Furthermore, it can also be that after polishing the surface of the area where the semiconductor substrate is exposed outside the remaining nitrogen-containing mask layer by using the first etching solution first, the surface of the area where the semiconductor substrate is exposed outside the remaining nitrogen-containing mask layer is textured. In this case, polishing first can make the surfaces of all parts where the semiconductor substrate is exposed outside the remaining nitrogen-containing mask layer relatively flat, so that after texturing, the uniformity of the textured surface structures of all parts can be improved, and all parts of the surface have a good light trapping effect, further improving the yield of the formed solar cell.

[0020] As a possible implementation solution, the semiconductor substrate includes alternately arranged first regions and second regions. The first laser irradiation region is the second region. And after removing the nitrogen-containing mask layer located in the first laser irradiation region by using a first etching solution, the manufacturing method of the solar cell further includes: removing the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation region. Next, a second laser is used to irradiate a part of the nitrogen-containing mask layer in the non-edge region of the first region, so as to reduce the nitrogen content in the second laser irradiation region of the nitrogen-containing mask layer. Next, the nitrogen-containing mask layer in the first region that is not irradiated by the second laser is removed by using a second etching solution, and the nitrogen-containing mask layer located in the second laser irradiation region is retained. Next, a second semiconductor layer is formed in the second region and extends to cover the nitrogen-containing mask layer located in the second laser irradiation region. The conduction types of the second semiconductor layer and the first semiconductor layer are opposite.

[0021] In the case of adopting the above technical solution, during the actual manufacturing process, when removing the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation region, the etchant has side etching on the edge portion of the first semiconductor layer located under the nitrogen-containing mask layer that is not irradiated by the first laser, so that the edge portion of the nitrogen-containing mask layer that is not irradiated by the first laser extends out of the first semiconductor layer. In this case, if the second semiconductor layer is directly formed, the portion of the nitrogen-containing mask layer that extends out of the first semiconductor layer will affect the coating of the second semiconductor layer on the side wall of the first semiconductor layer, resulting in a relatively large number of defects at this location. However, in the manufacturing method provided by the present invention, after removing the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation region, the remaining nitrogen-containing mask layer and the first semiconductor layer are stacked in the first region. Next, a second laser is used to irradiate a part of the nitrogen-containing mask layer in the non-edge region of the first region, so that the nitrogen content in the second laser irradiation region of the nitrogen-containing mask layer is reduced, so that at least part of the region of the nitrogen-containing mask layer irradiated by the second laser has high corrosion resistance to the second etching solution, while the nitrogen content in the region of the nitrogen-containing mask layer that is not irradiated by the second laser is relatively high, resulting in relatively low corrosion resistance of this part to the second etching solution. Therefore, the second etching solution can be used to further selectively etch the nitrogen-containing mask layer, eliminate the influence of the part of the nitrogen-containing mask layer that extends out of the first semiconductor layer on the second semiconductor layer, improve the coating of the second semiconductor layer on the side wall of the first semiconductor layer, and reduce the number of defects at this location. And at least part of the nitrogen-containing mask layer retained in the second laser irradiation region can be used as an insulating layer between the first semiconductor layer and the second semiconductor layer with opposite conduction types, electrically isolating the two, reducing the leakage risk of the manufactured solar cell, and at the same time reducing the thermal damage degree to the first semiconductor layer and the semiconductor substrate located under the nitrogen-containing mask layer in the second laser irradiation region, improving the yield and working performance of the manufactured solar cell.

[0022] As a possible implementation solution, a second etching solution is used to remove the nitrogen-containing mask layer in the first region that is not irradiated by the second laser, and the nitrogen-containing mask layer in the second laser irradiation region is retained, including: using the second etching solution to remove the nitrogen-containing mask layer in the first region that is not irradiated by the second laser, and thinning the nitrogen-containing mask layer in the second laser irradiation region.

[0023] In the case of adopting the above technical solution, on the premise of ensuring that the remaining nitrogen-containing mask layer in the second laser irradiation region after thinning can electrically isolate the first semiconductor layer and the second semiconductor layer with opposite conduction types, there is no need to strictly limit the type of the second etching solution and / or the etching conditions in order to ensure that all of the nitrogen-containing mask layer in the second laser irradiation region is retained, thereby reducing the process difficulty of using the second etching solution to remove the nitrogen-containing mask layer in the first region that is not irradiated by the second laser.

[0024] As a possible implementation solution, in the case of the same laser wavelength and laser pulse width, the power density of the second laser is less than that of the first laser. In this case, it can be prevented that due to the too high power density of the second laser, excessive nitrogen elements escape in the part of the nitrogen-containing mask layer in the second laser irradiation region close to the first semiconductor layer, resulting in the loosening of its own structure, and ensuring that at least the part of the nitrogen-containing mask layer in the second laser irradiation region close to the first semiconductor layer has high corrosion resistance to the second etching solution. Thus, after removing the nitrogen-containing mask layer in the first region that is not irradiated by the second laser, at least the part of the nitrogen-containing mask layer in the second laser irradiation region close to the first semiconductor layer is retained, which is beneficial to reducing the leakage risk between the first semiconductor layer and the second semiconductor layer.

[0025] As a possible implementation solution, a first semiconductor layer and a nitrogen-containing mask layer are sequentially formed in a stacked manner on a semiconductor substrate, including: a first semiconductor layer, a surface passivation layer and a nitrogen-containing mask layer are sequentially formed in a stacked manner on the semiconductor substrate. And, using a first etching solution to remove the first laser irradiation region, including: using the first etching solution to remove the nitrogen-containing mask layer in the first laser irradiation region, the surface passivation layer and the first semiconductor layer below the nitrogen-containing mask layer in the first laser irradiation region.

[0026] In the case of adopting the above technical solution, through the manufacturing method provided by the present invention, under the protection of the part of the nitrogen-containing mask layer not irradiated by the first laser, patterning of the first semiconductor layer and the surface passivation layer can be realized, the degree of thermal damage to the part of the semiconductor substrate corresponding to the first laser irradiation region after patterning is reduced, and the yield of the manufactured solar cell is improved.

[0027] As a possible implementation solution, after removing the nitrogen-containing mask layer located in the first laser irradiation area by using the first etching solution, the manufacturing method of the solar cell further includes: forming a first electrode on the part of the nitrogen-containing mask layer removed by the first etching solution. The first electrode is electrically connected to the first semiconductor layer. In this case, through the manufacturing method provided by the present invention, patterning of the nitrogen-containing mask layer located on the first semiconductor layer can be realized to form a conductive window for filling the first electrode, reduce the degree of thermal damage to the part of the first semiconductor layer and the semiconductor substrate corresponding to the first laser irradiation area after patterning, and improve the yield of the manufactured solar cell.

[0028] As a possible implementation solution, the semiconductor substrate includes opposite first and second surfaces. And, a first semiconductor layer and a nitrogen-containing mask layer are sequentially formed in a stacked manner on the semiconductor substrate, including: sequentially forming a stacked first semiconductor layer and a nitrogen-containing mask layer on the first surface of the semiconductor substrate, and forming a nitrogen-containing mask layer at the edge of the second surface of the semiconductor substrate. Next, the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate is irradiated with a third laser to reduce the nitrogen content in the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate. Next, the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate is removed by using a third etching solution. In this case, the degree of thermal damage to the part of the semiconductor substrate close to the edge of the second surface after removing the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate can be reduced, the yield of the solar cell can be improved, and it is beneficial for the manufactured solar cell to have good working performance.

[0029] As a possible implementation solution, the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride. After being irradiated with the first laser, in the nitrogen-containing mask layer, the nitrogen-silicon ratio in the part located in the first laser irradiation area is less than that in the remaining part.

[0030] In the case of adopting the above technical solution, silicon nitride and silicon oxynitride can not only play the role of protecting the mask layer, but also have good insulation, passivation and antireflection effects, and are insulating materials with relatively comprehensive performance. Therefore, when the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride, it is beneficial to improve the working performance of the manufactured solar cell.

[0031] As a possible implementation solution, a part of the nitrogen-containing mask layer is irradiated with the first laser. Among them, the nitrogen-containing mask layer in the area not irradiated with the first laser includes an amorphous state, and at least part of the nitrogen-containing mask layer in the first laser irradiation area includes a crystalline state.

[0032] In the case of adopting the above technical solution, the nitrogen-containing mask layer itself is amorphous, and at least part of the nitrogen-containing mask layer located in the first laser irradiation area forms a crystalline state after being irradiated by the first laser, which can change the corrosion resistance of at least part of the nitrogen-containing mask layer located in the first laser irradiation area to different etching solutions. For example, the corrosion resistance of at least part of the nitrogen-containing mask layer located in the first laser irradiation area to alkaline etching solutions and the like can be reduced, so as to improve the rate of removing the nitrogen-containing mask layer located in the first laser irradiation area by using alkaline etching solutions and the like, and improve the manufacturing efficiency.

[0033] As a possible implementation solution, an oxide layer is formed on the surface of at least part of the nitrogen-containing mask layer located in the first laser irradiation area. In this case, the formation of the oxide consumes nitrogen element, or silicon element, or both nitrogen element and silicon element, etc. in the nitrogen-containing mask layer. Compared with at least part of the nitrogen-containing mask layer located in the first laser irradiation area, the stability and corrosion resistance of the oxide layer are relatively low for alkaline etching solutions and the like, which is conducive to subsequent removal of the nitrogen-containing mask layer located in the first laser irradiation area by using the first etching solution. Description of the Drawings

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0035] Figure 1 It is a flowchart of the manufacturing method of the solar cell provided by the embodiment of the present invention;

[0036] Figure 2 It is a schematic longitudinal sectional view of the structure of the solar cell formed by the manufacturing method provided by the embodiment of the present invention during the manufacturing process Figure 1 ;

[0037] Figure 3 It is a schematic longitudinal sectional view of the structure of the solar cell formed by the manufacturing method provided by the embodiment of the present invention during the manufacturing process Figure 2 ;

[0038] Figure 4 It is a schematic longitudinal sectional view of the structure of the solar cell formed by the manufacturing method provided by the embodiment of the present invention during the manufacturing process Figure 3 ;

[0039] Figure 5 It is a schematic longitudinal sectional view of the structure of the solar cell formed by the manufacturing method provided by the embodiment of the present invention during the manufacturing process Figure 4 ;

[0040] Figure 6Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 5 ;

[0041] Figure 7 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 6 ;

[0042] Figure 8 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 7 ;

[0043] Figure 9 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 8 ;

[0044] Figure 10 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 9 ;

[0045] Figure 11 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 ;

[0046] Figure 12 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 One;

[0047] Figure 13 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Two;

[0048] Figure 14 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Three;

[0049] Figure 15 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Four;

[0050] Figure 16 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Five;

[0051] Figure 17 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Six;

[0052] Figure 18 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Seven;

[0053] Figure 19 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Eight;

[0054] Figure 20 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 10 Nine;

[0055] Figure 21 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Ten;

[0056] Figure 22 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Eleven;

[0057] Figure 23 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Twelve;

[0058] Figure 24 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Thirteen;

[0059] Figure 25 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Fourteen;

[0060] Figure 26 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Fifteen;

[0061] Figure 27 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Sixteen;

[0062] Figure 28 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Seventeen;

[0063] Figure 29 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Eighteen;

[0064] Figure 30 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 2 Nineteen;

[0065] Figure 31 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Ten;

[0066] Figure 32 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Eleven;

[0067] Figure 33 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Twelve;

[0068] Figure 34 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Thirteen;

[0069] Figure 35 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Fourteen;

[0070] Figure 36 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Fifteen;

[0071] Figure 37 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Sixteen;

[0072] Figure 38 Longitudinal sectional schematic of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing processFigure 3 Seventeen;

[0073] Figure 39 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Eighteen;

[0074] Figure 40 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 3 Nineteen;

[0075] Figure 41 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 4 Ten;

[0076] Figure 42 Longitudinal sectional schematic view of the structure of the solar cell formed by the manufacturing method provided in the embodiment of the present invention during the manufacturing process Figure 4 Eleven;

[0077] Figure 43 Longitudinal TEM view of the structure of the manufacturing method provided in the embodiment of the present invention at the nitrogen-containing mask layer located in the first laser irradiation region.

[0078] Reference numerals: 11 is a semiconductor substrate, 12 is a first semiconductor layer, 13 is a nitrogen-containing mask layer, 14 is a first laser irradiation region, 15 is a hole structure, 16 is a first region, 17 is a second region, 18 is a second laser irradiation region, 19 is a second semiconductor layer, 20 is a surface passivation layer, 21 is a transparent conductive layer, 22 is a first electrode, 23 is a second electrode, 24 is a first interface passivation layer, 25 is a second interface passivation layer, 26 is a third region. Detailed implementation manners

[0079] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0080] Various structural schematic views according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where some details are enlarged for clearer expression and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0081] In the context of the present invention, when a layer / component is referred to as being "on" another layer / component, the layer / component can be directly on the other layer / component, or there can be an intermediate layer / component between them. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component can be "under" the other layer / component. In order to make the technical problems to be solved, technical solutions and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0082] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0083] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0084] A solar cell is a device that can convert the light energy of the sun into electrical energy. Specifically, when the solar cell is in a working state, sunlight shines on the semiconductor p-n junction of the solar cell, forming new hole-electron pairs. Under the action of the built-in electric field in the p-n junction, the photo-generated holes flow to the p region, and the photo-generated electrons flow to the n region. After connecting the circuit, an electric current can be generated. And patterning is an important step in the manufacturing process of solar cells. For example: the opening film treatment of the N-type or P-type semiconductor layer in the case where the N-type or P-type semiconductor layer is only located in a partial area on one side of the semiconductor substrate. Another example: the isolation treatment of two types of semiconductor layers with opposite conductivity types in a back contact cell. Another example: the selective grooving treatment of the passivation layer before metallization, etc. The above operations all require patterning.

[0085] However, in the existing manufacturing methods of solar cells, the above patterning process is usually achieved by means of laser etching process, chemical slurry etching process, photolithography combined with wet etching process, etc. The cost of the photolithography process is expensive, so the photolithography combined with wet etching process is less used to achieve patterning. In addition, the chemical slurry etching process has low precision and cumbersome operation, which is not conducive to improving the manufacturing efficiency and yield of solar cells. For the laser etching process, it directly etches and removes the mask layer to be removed (or the mask layer and the semiconductor layer, etc.) by using high-temperature laser. Although its etching precision is high, the production speed is fast, and the cost is relatively low, the commonly used laser etching process, for example, heats the semiconductor substrate with an extremely short pulse wave, thereby generating a large temperature gradient between the semiconductor substrate and the mask layer, and then generating extremely large stress, which causes the mask layer to burst and be removed under the action of the thermal stress. However, this film bursting method caused by the thermal stress requires a large laser energy density, which will inevitably damage the semiconductor substrate and the semiconductor layer, affecting the working performance of the solar cell.

[0086] In order to solve the above technical problems, an embodiment of the present invention provides a manufacturing method of a solar cell. Among them, the solar cell formed by the manufacturing method provided in the embodiment of the present invention can be a double-sided contact solar cell, that is, one of the positive electrode and the negative electrode of the manufactured solar cell is disposed on the front surface of the battery, and the other is disposed on the back surface of the battery. Or, the manufactured solar cell can also be a back contact battery, that is, both the positive electrode and the negative electrode of the manufactured solar cell are disposed on the back surface of the battery.

[0087] As Figure 1 shown, the manufacturing method of the solar cell provided in the embodiment of the present invention includes the following steps: First, a first semiconductor layer and a nitrogen-containing mask layer are sequentially formed on a semiconductor substrate. Next, a part of the nitrogen-containing mask layer is irradiated with a first laser to reduce the nitrogen content in the first laser irradiation area of the nitrogen-containing mask layer. Next, the nitrogen-containing mask layer located in the first laser irradiation area is removed by using a first etching solution.

[0088] It should be noted that in the manufacturing method provided in the embodiment of the present invention, removing the nitrogen-containing mask layer located in the first laser irradiation area by using the first etching solution can be directly etching and removing the nitrogen-containing mask layer located in the first laser irradiation area by the first etching solution, or can be etching and removing the first semiconductor layer or other film layers disposed between the nitrogen-containing mask layer located in the first laser irradiation area and the semiconductor substrate by the first etching solution, and indirectly removing the nitrogen-containing mask layer located in the first laser irradiation area by means of the peeled first semiconductor layer or other film layers, etc.

[0089] In the case of adopting the above technical solution, in the manufacturing method provided by the embodiment of the present invention, a part of the nitrogen-containing mask layer is irradiated with a first laser. During the irradiation of the first laser, the nitrogen-containing mask layer located in the first laser irradiation area is heated, so that the nitrogen element therein volatilizes in the form of nitrogen gas. Furthermore, in the nitrogen-containing mask layer after being irradiated by the first laser, the nitrogen content in the area irradiated by the first laser decreases, while the nitrogen content in the area not irradiated by the first laser remains unchanged, thereby realizing the modification treatment of part of the area in the nitrogen-containing mask layer. Based on this, different parts in different areas of the nitrogen-containing mask layer have different nitrogen contents, and the nitrogen-containing mask layer located in the first laser irradiation area and having a lower nitrogen content is removed by a first etching solution, thereby realizing the patterning treatment of the nitrogen-containing mask layer. It can be seen that in the manufacturing method provided by the embodiment of the present invention, only the nitrogen content in part of the nitrogen-containing mask layer is reduced by the first laser irradiation method, and then by the wet etching method, the nitrogen-containing mask layer located in the first laser irradiation area is removed by the first etching solution, rather than directly heating the nitrogen-containing mask layer to be removed by a high-temperature laser, so that the nitrogen-containing mask layer corresponding to the laser irradiation area undergoes film bursting or gasification. Compared with directly removing the nitrogen-containing mask layer by a high-temperature laser, the energy of the first laser is much lower. Therefore, the degree of thermal damage to the part of the semiconductor substrate (or to the semiconductor substrate and the first semiconductor layer) located below the nitrogen-containing mask layer in the first laser irradiation area can be reduced, the yield of the solar cell can be improved, and it is beneficial for the manufactured solar cell to have good working performance.

[0090] The following will be based on Figures 2 to 42 The cross-sectional view of the operation shown, and the manufacturing process of the solar cell provided by the embodiment of the present invention will be described in multiple embodiments:

[0091] Embodiment 1

[0092] The first step: As Figure 2 and Figure 3 shown, a first semiconductor layer 12 and a nitrogen-containing mask layer 13 are sequentially formed in a stacked manner on a semiconductor substrate 11.

[0093] Specifically, the embodiment of the present invention does not make specific limitations on the material of the semiconductor substrate. The semiconductor substrate can be a substrate of any semiconductor material such as a silicon substrate, a silicon-germanium substrate, a germanium substrate, or a gallium arsenide substrate. In addition, the conductivity type of the semiconductor substrate can be N-type, P-type, or of course, intrinsic type.

[0094] For the above-mentioned first semiconductor layer, the material of the first semiconductor layer can include any semiconductor material such as silicon, silicon-germanium, germanium, or gallium arsenide. In terms of the arrangement form of substances, the crystal phase of the first semiconductor layer can be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc. In addition, the conductivity type of the first semiconductor layer can be N-type or P-type.

[0095] For the above nitrogen-containing mask layer, its material may include any insulating material containing nitrogen elements, as long as it can be applied to the manufacturing method provided in the embodiments of the present invention.

[0096] Exemplarily, the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride. In this case, silicon nitride and silicon oxynitride can not only play the role of protecting the mask layer, but also have good insulation, passivation and antireflection effects. They are insulating materials with relatively comprehensive performance. Therefore, when the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride, it is beneficial to improve the working performance of the manufactured solar cell. Specifically, when the nitrogen-containing mask layer includes multiple materials, the distribution of different materials within the nitrogen-containing mask layer can be determined according to the actual manufacturing process. For example: in the case where the material of the nitrogen-containing mask layer includes silicon nitride and silicon oxynitride, the silicon nitride material in the nitrogen-containing mask layer can be distributed on the side close to the first semiconductor layer, while the silicon oxynitride material is distributed on the side away from the first semiconductor layer. Specifically, the nitrogen-containing mask layer can be a single-layer structure or a stacked structure composed of at least two mask layers.

[0097] As for the thickness and refractive index of the above nitrogen-containing mask layer, they can be set according to actual needs and are not specifically limited here. Exemplarily, the thickness of the nitrogen-containing mask layer can be greater than or equal to 2 nm and less than or equal to 150 nm. For example: the thickness of the nitrogen-containing mask layer can be 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 80 nm, 100 nm, 120 nm, 140 nm or 150 nm, etc.

[0098] Exemplarily, the refractive index of the nitrogen-containing mask layer can be greater than or equal to 1.9 and less than or equal to 2.6. For example: the refractive index of the nitrogen-containing mask layer can be 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 or 2.6, etc.

[0099] In the actual manufacturing process, after providing the semiconductor substrate, in some examples, the semiconductor substrate can be pre-cleaned to remove the cutting damage on the surface of the semiconductor substrate, as well as the organic matter and other pollutants generated during the transportation process, so as to improve the yield of the manufactured solar cell. Next, a process such as chemical vapor deposition can be used to form a first intrinsic semiconductor layer on the semiconductor substrate. Then, the first intrinsic semiconductor layer is doped by diffusion, ion implantation or doping source coating, so that the first intrinsic semiconductor layer forms a first semiconductor layer. Among them, if the material of the first semiconductor layer includes silicon and the first intrinsic semiconductor layer is doped by diffusion, after the first semiconductor layer is formed, a first doped silicon glass layer will also be formed on the side of the first semiconductor layer away from the semiconductor substrate. In this case, before forming the nitrogen-containing mask layer, a process such as wet or dry etching can be used to remove the first doped silicon glass layer; or the first doped silicon glass layer can also be retained. Next, a process such as chemical vapor deposition can be used to form a nitrogen-containing mask layer on the first semiconductor layer (or on the first doped silicon glass layer).

[0100] It should be noted that if Figure 2 As shown, the first intrinsic semiconductor layer for manufacturing the first semiconductor layer 12 may be formed directly on the semiconductor substrate 11 by adopting the above manufacturing method. Figure 3 As shown, before forming the above-mentioned first intrinsic semiconductor layer, a first interface passivation layer 24 is first formed on the semiconductor substrate 11 by using processes such as thermal oxidation or chemical vapor deposition, and then a first intrinsic semiconductor layer is formed on the first interface passivation layer 24. In this case, the passivation contact structure composed of the first interface passivation layer 24 and the first semiconductor layer 12 formed based on the first intrinsic semiconductor layer has an excellent interface passivation effect, and can achieve selective collection of carriers, reduce the carrier recombination rate at the region where the first interface passivation layer 24 and the first semiconductor layer 12 are provided on the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the manufactured solar cell. The material and thickness of the first interface passivation layer 24 can be set according to the material of the first semiconductor layer 12 and actual needs, and are not specifically limited here. For example: when the material of the first semiconductor layer is doped polysilicon, the first interface passivation layer is a tunneling passivation layer. For another example, when the material of the first semiconductor layer includes at least one of doped amorphous silicon, doped microcrystalline silicon and doped nanocrystalline silicon, the first interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer or a mixture of the above three.

[0101] In addition, it can be understood that the semiconductor substrate includes opposite first and second surfaces. If in the first step, a first semiconductor layer and a nitrogen-containing mask layer are sequentially formed in a stacked manner on the first surface of the semiconductor substrate, then during the formation of the nitrogen-containing mask layer, a nitrogen-containing mask layer may also be formed on the edge of the second surface of the semiconductor substrate due to overplating.

[0102] Second step: As Figure 4 shown, a first laser is used to irradiate a partial area of the nitrogen-containing mask layer 13 to reduce the nitrogen content in the first laser irradiation area 14 of the nitrogen-containing mask layer 13.

[0103] Specifically, in the embodiments of the present invention, the irradiation conditions of the first laser such as wavelength, pulse width, and power density, as well as the reduction degree of the nitrogen content in the first laser irradiation area of the nitrogen-containing mask layer can be set according to actual requirements, as long as it can satisfy the removal of the nitrogen-containing mask layer located in the first laser irradiation area with the first etching solution in the subsequent process and retain the part of the nitrogen-containing mask layer that is not irradiated by the first laser. In addition, the reduction of the nitrogen content in the first laser irradiation area of the nitrogen-containing mask layer means that the nitrogen content in the first laser irradiation area is reduced relative to before the first laser irradiation or relative to the area that is not irradiated by the first laser; the specific meaning of the reduction of the nitrogen content in the first laser irradiation area of the nitrogen-containing mask layer can be determined according to the material of the nitrogen-containing mask layer. For example: when the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride, the reduction of the nitrogen content in the first laser irradiation area of the nitrogen-containing mask layer means that: after the first laser irradiation, the nitrogen-silicon ratio in the first laser irradiation area of the nitrogen-containing mask layer is reduced. Specifically, after the first laser irradiation, in the nitrogen-containing mask layer, the nitrogen-silicon ratio in the part located in the first laser irradiation area is less than that in the remaining part.

[0104] Secondly, exemplarily, an oxide layer may be formed on the surface of at least part of the nitrogen-containing mask layer located in the first laser irradiation area. In this case, the formation of the oxide consumes nitrogen element, or silicon element, or both nitrogen element and silicon element in the nitrogen-containing mask layer. Compared with at least part of the nitrogen-containing mask layer located in the first laser irradiation area, the stability and corrosion resistance of the oxide layer are relatively low for alkaline etching solutions and the like, which is conducive to the subsequent removal of the nitrogen-containing mask layer located in the first laser irradiation area with the first etching solution. Among them, the above oxide layer may include a silicon oxide layer and / or a silicon oxynitride layer, etc.

[0105] In some embodiments, if the thickness of the oxide layer is too thick, the manufacturing difficulty is relatively high, and the time or temperature required to form the oxide layer is relatively long or high. For example, the time and / or power density of the first laser irradiation are too large. If the thickness of the oxide layer is too low, the thickness of the nitrogen-containing mask layer consumed is relatively small, and the improvement degree of the etching rate for subsequently removing the nitrogen-containing mask layer located in the first laser irradiation area with the first etching solution is relatively low. Therefore, in this technical solution, the thickness of the oxide layer can be 10% to 50% of the thickness of the nitrogen-containing mask layer. In this way, while ensuring the stability of the nitrogen-containing mask layer, the processing difficulty of the oxide layer and the time and / or power density of the first laser irradiation are reduced. Exemplarily, the thickness of the oxide layer is 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48% or 50% of the thickness of the nitrogen-containing mask layer, etc.

[0106] In addition, the material of the oxide layer may include silicon oxide and / or silicon oxynitride. Specifically, the silicon atoms on the surface of the nitrogen-containing mask layer located in the first laser irradiation area come into contact with oxygen and react to form an oxide layer.

[0107] In some embodiments, along the direction close to the first semiconductor layer, the oxygen content in at least part of the nitrogen-containing mask layer located in the first laser irradiation area may gradually decrease. With such a setting, the oxygen content on the outer surface of at least part of the nitrogen-containing mask layer located in the first laser irradiation area is the largest, which is convenient for subsequently using the first etching solution to quickly remove the nitrogen-containing mask layer located in the first laser irradiation area.

[0108] In addition, as Figures 4 to 6As shown, after the first laser irradiation, holes 15 can be formed in the portion of the nitrogen-containing mask layer 13 located in the first laser irradiation region 14. In this case, the presence of the holes 15 makes the structure of the portion of the nitrogen-containing mask layer 13 located in the first laser irradiation region 14 looser, so that the first etchant can contact the inside of the nitrogen-containing mask layer 13 located in the first laser irradiation region 14 through the holes 15, increasing the etching area and etching rate of the first etchant on the nitrogen-containing mask layer 13 located in the first laser irradiation region 14. While improving the patterning processing productivity, the contact time between the first etchant and the nitrogen-containing mask layer located in the non-first laser irradiation region is shortened, which is beneficial to further reducing the influence of the first etchant on the portion of the nitrogen-containing mask layer 13 that is not irradiated by the first laser, and improving the patterning processing accuracy. Alternatively, the first etchant can etch the first semiconductor layer 12 or other film layers (such as a surface passivation layer, etc.) disposed under the nitrogen-containing mask layer 13 located in the first laser irradiation region 14 through the holes 15, so as to remove the nitrogen-containing mask layer 13 located in the first laser irradiation region 14 by a stripping method, providing another example for the manufacturing method provided by the embodiments of the present invention, and improving the applicability of the manufacturing method provided by the embodiments of the present invention in different application scenarios.

[0109] The distribution of the above-mentioned holes in the first laser irradiation region and the size of the holes can be determined according to the requirements for the removal rate of the first etchant, the first laser irradiation conditions, and the requirements for the degree of thermal damage to the semiconductor substrate corresponding to the first laser irradiation region in the actual application scenario, and no specific limitation is made here.

[0110] Exemplarily, the maximum pore size of at least one hole structure may be greater than or equal to 5 nm and less than or equal to 20 μm. For example, the maximum pore size of at least one hole structure may be 5 nm, 10 nm, 20 nm, 50 nm, 100 nm, 300 nm, 500 nm, 700 nm, 800 nm, 1 μm, 5 μm, 10 μm, 15 μm or 20 μm, etc. In this case, the hole structure is formed because the first laser is used to irradiate part of the nitrogen-containing mask layer, so that the nitrogen-containing mask layer located in the first laser irradiation area is partially removed after being heated. The specific removal method may be, for example, thermal gasification, thermal film explosion, or heating to volatilize the nitrogen element in this part of the nitrogen-containing mask layer in the form of nitrogen gas, thereby forming a hole structure on the nitrogen-containing mask layer. Based on this, it can be understood that the higher the power density of the first laser, the larger the pore size and / or number of the hole structure formed in the nitrogen-containing mask layer. On the contrary, the lower the power density of the first laser, the smaller the aperture and / or number of the hole structure formed in the nitrogen-containing mask layer. In this case, the maximum aperture of at least one hole structure is within the above range, which is conducive to preventing the first etching liquid from removing the nitrogen-containing mask layer located in the first laser irradiation area at a low etching rate due to the maximum aperture of the hole structure being too small, and is conducive to improving manufacturing efficiency. In addition, it can also prevent the irradiation temperature of the first laser on the nitrogen-containing mask layer from being too high due to the hole structure being too large, further reducing the degree of thermal damage to the semiconductor substrate after patterning, improving the yield of the manufactured solar cell, and being conducive to the solar cell having good working performance. It should be noted that in the actual application process, adjacent hole structures may be connected, and at this time, multiple connected hole structures are considered to be one hole structure. Correspondingly, the maximum aperture of multiple connected hole structures is the aperture of the hole structure formed.

[0111] For the same hole structure, along the thickness direction of the nitrogen-containing mask layer, the pore diameters of different parts of the hole structure can be the same or different. When the pore diameters of different parts of the hole structure are different, the specific hole size of each part and the morphology of the hole structure can be set according to actual needs, and no specific limitation is made here.

[0112] Exemplarily, in at least one hole structure, the size of the hole opening on the side away from the first semiconductor layer is smaller than the size of the hole bottom on the side close to the first semiconductor layer. In this case, the size of the hole bottom of the hole structure is larger, which is conducive to the accumulation of the corresponding etching liquid at the hole bottom of the hole structure, and the etching rate of the etching liquid at the corresponding hole bottom portion of the nitrogen-containing passivation layer is increased, and the rate of removing the nitrogen-containing mask layer located in the first laser irradiation area is increased.

[0113] Exemplarily, at least one hole structure is in a quasi-cylindrical shape, a quasi-bowl shape, or a quasi-gourd shape. In this case, there are various examples of the morphology of the hole structure, which is beneficial to improving the applicability of the manufacturing method of the solar cell provided by the present invention in different actual application environments. Additionally, it is also beneficial to reducing the manufacturing process difficulty of forming the hole structure in the nitrogen-containing mask layer located in the first laser irradiation area.

[0114] In addition, when there are multiple hole structures in the nitrogen-containing mask layer located in the first laser irradiation area, the sizes of different hole structures can be the same or different. When the sizes of different hole structures are different, the distribution of the hole structures with different sizes in the first laser irradiation area can be determined according to actual needs, and no specific limitation is made here.

[0115] Among them, after being irradiated by the first laser, at least one hole structure in the nitrogen-containing mask layer located in the first laser irradiation area can be a blind hole with one end open and the other end closed (that is, the hole structure does not penetrate the nitrogen-containing mask layer). At least part of the above blind holes can form through holes penetrating the nitrogen-containing mask layer, or blind holes with increased depth and / or aperture after being etched by the first etching solution. Alternatively, at least one hole structure can be a through hole penetrating the nitrogen-containing mask layer. In this case, since the thickness of the nitrogen-containing mask layer is fixed, compared with the blind hole with one end open and the other end closed (that is, the hole structure does not penetrate the nitrogen-containing mask layer), when at least one hole structure is a through hole penetrating the nitrogen-containing mask layer, the area of the nitrogen-containing mask layer exposed through the hole structure increases, which is more conducive to the first etching solution quickly etching the nitrogen-containing mask layer located in the first laser irradiation area, further increasing the etching rate of the first etching solution on the nitrogen-containing mask layer located in the first laser irradiation area. Alternatively, the first etching solution can directly etch the first semiconductor layer or other film layers provided under the nitrogen-containing mask layer located in the first laser irradiation area through the hole structure, without having to etch through the hole structure to contact the first semiconductor layer or other film layers, further improving the rate of removing the nitrogen-containing mask layer located in the first laser irradiation area, and improving the efficiency and productivity of the patterning process.

[0116] Among them, in the nitrogen-containing mask layer located in the first laser irradiation area, the number and distribution of the hole structures as blind holes and the hole structures as through holes can be determined according to the first laser irradiation conditions and actual needs, and no specific limitation is made here.

[0117] In the actual application process, after the first laser irradiation, in the nitrogen-containing mask layer, the corrosion resistance of the portion located in the first laser irradiation area to the first etching liquid can be less than the corrosion resistance of the remaining portion to the first etching liquid. In this case, the etching rate difference between the portion irradiated by the first laser and the portion not irradiated by the first laser in the nitrogen-containing mask layer can be at least utilized to achieve selective etching of the nitrogen-containing mask layer located in the first laser irradiation area, reduce the influence of the first etching liquid on the portion of the nitrogen-containing mask layer not irradiated by the first laser, improve the patterning processing accuracy, and thus improve the yield of the manufactured solar cell. Among them, the corrosion resistance of the first laser irradiated area and the non-first laser irradiated area in the nitrogen-containing mask layer to the first etching liquid is determined according to the type of the first etching liquid. When the first etching liquid is an acidic etching liquid, after the first laser irradiation, in the nitrogen-containing mask layer, the acid corrosion resistance of the portion located in the first laser irradiation area to the first etching liquid is less than the acid corrosion resistance of the remaining portion to the first etching liquid. When the first etching solution is an alkaline etching solution, after the first laser irradiation, in the nitrogen-containing mask layer, the portion located in the first laser irradiation area has a lower alkaline corrosion resistance to the first etching solution than the remaining portion.

[0118] For example: when the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon nitride oxide, after the first laser irradiation, the alkali corrosion resistance of the part of the nitrogen-containing mask layer located in the first laser irradiation area to the first etching solution may be lower than the alkali corrosion resistance of the remaining part to the first etching solution.

[0119] It should be noted that, in the actual application process, the nitrogen-containing mask layer located in the first laser irradiation area may be subsequently removed by using the first etching liquid only because the nitrogen-containing mask layer in the first laser irradiation area has a hole structure. It may also be that after the first laser irradiation, the corrosion resistance of the portion of the nitrogen-containing mask layer located in the first laser irradiation area to the first etching liquid is less than that of the remaining portion, so that the nitrogen-containing mask layer located in the first laser irradiation area may be removed by using the first etching liquid. It may also be that the nitrogen-containing mask layer located in the first laser irradiation area may be removed by using the above-mentioned hole structure and the corrosion resistance of the portion located in the first laser irradiation area to the first etching liquid being less than that of the remaining portion.

[0120] In addition, for example, Figure 43As shown, a part of the nitrogen-containing mask layer is irradiated with a first laser. Among them, the nitrogen-containing mask layer in the area not irradiated by the first laser includes an amorphous state, and at least a part of the nitrogen-containing mask layer in the first laser irradiation area includes a crystalline state. In this case, the nitrogen-containing mask layer itself is in an amorphous state, and at least a part of the nitrogen-containing mask layer in the first laser irradiation area forms a crystalline state after being irradiated by the first laser, which can change the corrosion resistance of at least a part of the nitrogen-containing mask layer in the first laser irradiation area to different etching solutions. For example, it is possible to reduce the corrosion resistance of at least a part of the nitrogen-containing mask layer in the first laser irradiation area to etching solutions such as alkaline, thereby increasing the rate of removing the nitrogen-containing mask layer in the first laser irradiation area using an etching solution such as alkaline, and improving the manufacturing efficiency.

[0121] In some embodiments, the crystalline state appearing in the nitrogen-containing mask layer includes one or more of crystalline silicon, crystalline silicon nitride, and crystalline silicon oxynitride. Specifically, the crystalline state formed by at least a part of the nitrogen-containing mask layer in the first laser irradiation area may include only crystalline silicon, or only crystalline silicon nitride, or only crystalline silicon oxynitride. Or, the crystalline state formed by at least a part of the nitrogen-containing mask layer in the first laser irradiation area may include any two of crystalline silicon, crystalline silicon nitride, and crystalline silicon oxynitride; or, the crystalline state includes crystalline silicon, crystalline silicon nitride, and crystalline silicon oxynitride. In addition, the size of the crystalline state that appears may be in the micron scale or the nanometer scale. Among them, the size of crystalline silicon, crystalline silicon nitride, and / or crystalline silicon oxynitride is from 0.01 nm to 100 nm. For example, the size of crystalline silicon, crystalline silicon nitride, and / or crystalline silicon oxynitride is 0.01 nm, 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm, etc. For example, the crystalline silicon is nanocrystalline silicon.

[0122] In other embodiments, from the surface of at least a part of the nitrogen-containing mask layer irradiated by the first laser to the surface not irradiated by the first laser, the degree of crystallization of at least a part of the nitrogen-containing mask layer in the first laser irradiation area can gradually decrease. With such a setting, the degree of crystallization of at least a part of the nitrogen-containing mask layer on the surface in the first laser irradiation area is higher, which is more conducive to reducing the corrosion resistance of at least a part of the nitrogen-containing mask layer in the first laser irradiation area to the first etching solution and improving the removal efficiency.

[0123] As for the range of the nitrogen-containing mask layer irradiated by the first laser, it can be determined according to the type of solar cell and actual requirements, and no specific limitation is made here.

[0124] Exemplarily, such as Figure 4As shown, the semiconductor substrate 11 may have alternatingly distributed first regions 16 and second regions 17. The first laser irradiation region 14 is the second region 17. And, in the manufactured solar cell, the first semiconductor layer 12 is located in the first region 16. Moreover, the solar cell further includes a second semiconductor layer disposed in the second region and extending to cover a part of the first semiconductor layer. The conductivity type of the second semiconductor layer is opposite to that of the first semiconductor layer. In this case, the range of the above-mentioned first laser irradiation region 14 can be determined according to the range of the part of the second semiconductor layer disposed on the semiconductor substrate 11 in the actual application scenario, and no specific limitation is made here.

[0125] The third step: As Figure 7 As shown, a first etching solution is used to remove the nitrogen-containing mask layer 13 located in the first laser irradiation region, and the first semiconductor layer 12 located under the nitrogen-containing mask layer 13 in the first laser irradiation region is removed. In this case, through the manufacturing method provided by the embodiments of the present invention, under the protection of the part of the nitrogen-containing mask layer 13 that is not irradiated by the first laser, patterning of the first semiconductor layer 12 can be achieved, the degree of thermal damage to the part of the semiconductor substrate 11 corresponding to the first laser irradiation region after patterning is reduced, and the yield of the manufactured solar cell is improved.

[0126] Specifically, as described above, removing the nitrogen-containing mask layer located in the first laser irradiation region using the first etching solution may be directly etching and removing the nitrogen-containing mask layer located in the first laser irradiation region using the first etching solution. At this time, the type and etching conditions of the first etching solution can be determined according to the materials of the nitrogen-containing mask layer and the first semiconductor layer, and the difference between the nitrogen content in the nitrogen-containing mask layer in the first laser irradiation region and the nitrogen content in the nitrogen-containing mask layer in the region not irradiated by the first laser. No specific limitation is made here. In this case, it may be to use the first etching solution to only etch and remove the nitrogen-containing mask layer located in the first laser irradiation region, and then use other etching solutions to etch and remove the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation region. Or, it may also be to use the first etching solution to simultaneously remove the nitrogen-containing mask layer located in the first laser irradiation region and the first semiconductor layer located under the nitrogen-containing mask layer in the first laser irradiation region.

[0127] Alternatively, when a hole structure is formed in the nitrogen-containing mask layer, it is also possible to etch and remove other film layers disposed between the nitrogen-containing mask layer and the semiconductor substrate in the first laser irradiation region through a first etchant. The other film layer may be, for example, a first semiconductor layer, or a first semiconductor layer and a surface passivation layer, or a first doped silicon glass layer or other film layers to be patterned. The nitrogen-containing mask layer in the first laser irradiation region is indirectly removed by means of other film layer stripping or the like. At this time, the type and etching conditions of the first etchant need to be determined according to the material of the first semiconductor layer (or the first semiconductor layer and other film layers to be pattern-processed) disposed between the nitrogen-containing mask layer and the semiconductor substrate in the first laser irradiation region, which are not specifically limited herein.

[0128] For example: when the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride, and the first semiconductor layer is a first silicon layer, the first etchant may be an alkaline solution such as sodium hydroxide and / or potassium hydroxide. In this case, after the first laser irradiation, the nitrogen content in the nitrogen-containing mask layer in the first laser irradiation region decreases, and the silicon content increases, making the nitrogen-containing mask layer in the first laser irradiation region resistant to alkaline solution etching. Moreover, the alkaline solution can etch the first silicon layer.

[0129] Step 4: Polish and / or texture the surface of the region of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer using the first etchant. In this case, after removing the first semiconductor layer under the nitrogen-containing mask layer in the first laser irradiation region, the surface of the region of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer can be polished using the first etchant under the protection of the nitrogen-containing mask layer not irradiated by the first laser, so as to improve the flatness of the surface of this region, which is beneficial to improving the formation quality and deposition film thickness of the film layer (such as a surface passivation layer, an antireflection layer, a second semiconductor layer, etc.) formed on the surface of this region, and improving the working performance of the solar cell. As Figure 8 shown, texturing the surface of the region of the semiconductor substrate 11 exposed outside the remaining nitrogen-containing mask layer 13 using the first etchant can improve the light trapping effect of the surface of this region, increase the utilization rate of incident light, and thus improve the bifaciality of the manufactured solar cell. Alternatively, the texturing treatment can increase the specific surface area of the second semiconductor layer formed on the surface of this region, increase the contact area between the second semiconductor layer and the corresponding conductive material, and reduce the contact resistance. In addition, it is also beneficial to increase the contact area between the second semiconductor layer in the second region 17 and the corresponding electrode, improve the contact performance between the second semiconductor layer and the corresponding electrode, and further improve the working performance of the manufactured solar cell.

[0130] It should be noted that the manufacturing method provided by the embodiments of the present invention causes less thermal damage to the semiconductor substrate when irradiating the nitrogen-containing mask layer with the first laser. Therefore, after removing the nitrogen-containing mask layer located in the first laser irradiation area and the first semiconductor layer located below the nitrogen-containing mask layer in the first laser irradiation area with the first etching solution, texturing treatment can be directly performed on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer. After the texturing treatment, the morphology of the textured structure on each part of the surface is relatively uniform, and no additional polishing treatment is required, which is beneficial to simplifying the manufacturing efficiency of solar cells.

[0131] In addition, if a higher requirement for the uniformity of the textured structure on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer is required during the actual manufacturing process, polishing treatment can be first performed on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer with the first etching solution, and then texturing treatment can be performed on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer. In this case, performing the polishing treatment first can make each part of the surface of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer relatively flat. Thus, after the texturing treatment, the uniformity of the textured structure on each part of the surface is improved, so that each part of the surface has a good light trapping effect and / or reduces the contact resistance between the second semiconductor layer and the corresponding conductive material, further improving the yield of the formed solar cell.

[0132] It should be noted that after performing the above-mentioned polishing treatment on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer with the first etching solution, texturing treatment may not be performed. Alternatively, after performing the above-mentioned polishing treatment on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer with the first etching solution, other etching solutions may be additionally used to perform texturing treatment on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer.

[0133] Of course, in some cases, the operation of the above-mentioned fourth step may not be performed. In other cases, other etching solutions may be used to perform polishing treatment and / or texturing treatment on the surface of the area of the semiconductor substrate exposed outside the remaining nitrogen-containing mask layer.

[0134] Step Five: As Figures 9 to 11 shown, a second semiconductor layer 19 is formed in the second region 17 and extends to cover at least a part of the nitrogen-containing mask layer 13 in the first region 16. The conductivity type of the second semiconductor layer 19 is opposite to that of the first semiconductor layer 12.

[0135] Specifically, in terms of materials, the material of the second semiconductor layer may include any one of semiconductor materials such as silicon, silicon germanium, germanium, or gallium arsenide. In terms of the arrangement form of substances, the crystal phase of the second semiconductor layer may be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc. The ratio of the width of the second semiconductor layer extending and covering the nitrogen-containing mask layer located in the first region to the width of the first region can be set according to actual needs and will not be specifically limited here.

[0136] In an actual manufacturing process, by way of example, when the material of the second semiconductor layer is doped polysilicon and / or doped single-crystalline silicon and other materials, processes such as chemical vapor deposition can be used to form a second intrinsic semiconductor layer on the second region of the semiconductor substrate and on the nitrogen-containing mask layer located in the first region. Then, processes such as diffusion, ion implantation, or dopant source coating are used to dope the second intrinsic semiconductor layer so that the second intrinsic semiconductor layer forms the second semiconductor layer. Among them, if the material of the second semiconductor layer includes silicon and the second intrinsic semiconductor layer is doped by a diffusion process, a second doped silicon glass layer will also be formed on the side of the second semiconductor layer facing away from the semiconductor substrate after the second semiconductor layer is formed. In this case, heat treatment can be performed on a part of the second doped silicon glass layer located in the first region by means of laser irradiation or the like, so that the non-heat-treated part of the second doped silicon glass layer forms a mask layer; or, in the case of retaining the second doped silicon glass layer, processes such as deposition and selective etching are sequentially used to form a mask layer covering the second doped silicon glass layer located in the second region and a part of the first region (the material of this mask layer can include materials such as silicon nitride and / or aluminum oxide); or, alternatively, the second doped silicon glass layer can be removed, or in the case where the above-mentioned second doped silicon glass layer is not formed, processes such as deposition and selective etching are sequentially used to form a mask layer covering the second semiconductor layer located in the second region and a part of the first region. Next, at least under the protection of the mask layer, patterning is performed on the second semiconductor layer and the nitrogen-containing mask layer located in the first region, and only the part of the second semiconductor layer and the nitrogen-containing mask layer covering a part of the first semiconductor layer located in the first region, and the part of the second semiconductor layer located in the second region are retained. Among them, the part of the nitrogen-containing mask layer remaining between the overlapping first semiconductor layer and the second semiconductor layer can be used as an insulating layer for electrically isolating the first semiconductor layer and the second semiconductor layer with opposite conduction types. Among them, after patterning, in the first region, the sidewall of the second semiconductor layer can be aligned with the sidewall of the nitrogen-containing mask layer; at this time, after patterning, the second semiconductor layer covers the entire nitrogen-containing mask layer located in the first region. Or, after patterning, in the first region, the sidewall of the second semiconductor layer can also be recessed inward by a certain distance relative to the sidewall of the nitrogen-containing mask layer (the size of this distance can be set according to actual needs and is not specifically limited here) to reduce the risk of leakage. At this time, after patterning, the second semiconductor layer covers a part of the nitrogen-containing mask layer located in the first region.

[0137] Alternatively, when the material of the second semiconductor layer includes doped amorphous silicon, doped microcrystalline silicon, or doped nanocrystalline silicon, the second semiconductor layer can be directly formed on the second region of the semiconductor substrate and on the nitrogen-containing mask layer located in the first region. Then, processes such as deposition and selective etching are sequentially used to form a mask layer covering the second semiconductor layer located in the second region and part of the first region. Next, at least under the protection of the mask layer, the second semiconductor layer and the nitrogen-containing mask layer located in the first region are patterned, and only the part of the second semiconductor layer and the nitrogen-containing mask layer covering the part of the first semiconductor layer located in the first region and the part of the second semiconductor layer located in the second region are retained. In this case, instead of forming the above mask layer, processes such as laser etching can also be used to directly pattern the second semiconductor layer.

[0138] It should be noted that, as Figure 9 shown, the second semiconductor layer 19 can be directly formed on the second region 17 of the semiconductor substrate 11 and on the nitrogen-containing mask layer 13 located in the first region 16 by using the above manufacturing method. Alternatively, as Figure 11 shown, before forming the above second semiconductor layer, processes such as chemical vapor deposition can be used to first form a second interface passivation layer 25 on the second region 17 of the semiconductor substrate 11 and on the nitrogen-containing mask layer 13 located in the first region 16, and then form the second semiconductor layer on the second interface passivation layer 25. In this case, the passivation contact structure composed of the second interface passivation layer 25 and the second semiconductor layer 19 has excellent interface passivation effect, and can realize selective collection of carriers, reduce the carrier recombination rate at the region of the semiconductor substrate 11 where the second interface passivation layer 25 and the second semiconductor layer 19 are provided, and further improve the photoelectric conversion efficiency of the manufactured solar cell. The material and thickness of the second interface passivation layer 25 can be set according to the material of the second semiconductor layer 19 and actual requirements, and are not specifically limited here. For example: when the material of the second semiconductor layer is doped polysilicon, the second interface passivation layer is a tunneling passivation layer. Another example: when the material of the second semiconductor layer includes at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the second interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer, or a mixed layer of the above three.

[0139] In addition, as described above, if a nitrogen-containing mask layer is also formed at the edge of the second surface of the semiconductor substrate during the formation of the nitrogen-containing mask layer on the first surface of the semiconductor substrate, after the first step of operation, the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate can be irradiated with a third laser to reduce the nitrogen content in the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate. Next, the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate is removed using a third etchant. In this case, the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate can be removed relatively quickly; and, compared with directly removing the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate using a laser, the degree of thermal damage to the portion of the semiconductor substrate near the edge of the second surface can be reduced, the yield of the solar cell can be improved, and it is beneficial for the manufactured solar cell to have good working performance. In addition, compared with directly removing the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate using an etchant, since the manufacturing method provided by the embodiment of the present invention requires a shorter time to remove the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate, the nitrogen-containing mask layer located on the side surface of the semiconductor substrate can be avoided from being removed, ensuring the passivation protection effect and physical isolation effect of the nitrogen-containing mask layer on the semiconductor substrate.

[0140] It should be noted that after irradiating the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate with the third laser, the changes in the nitrogen content, silicon-nitrogen ratio, crystal state of the nitrogen-containing mask layer, and the formation of an oxide layer on the surface of the nitrogen-containing mask layer in the third laser irradiation area can all refer to the changes in the nitrogen-containing mask layer in the first laser irradiation area, which will not be elaborated here.

[0141] Specifically, the operation of removing the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate using the third etchant can be carried out simultaneously with the above-mentioned third step of operation; or, it can also be carried out after the first step of operation and before the third step of operation; or, it can also be carried out after the third step of operation.

[0142] The third etchant can be the same as or different from the first etchant.

[0143] Sixth step: As Figure 12 shown, a passivation and antireflection layer is formed on one side of the second surface of the semiconductor substrate 11 using processes such as chemical vapor deposition to reduce the carrier recombination rate and reflectivity on one side of the second surface of the semiconductor substrate 11, and further improve the conversion efficiency of the manufactured solar cell. The material of the passivation and antireflection layer can be determined according to the actual application scenario and will not be specifically limited here. Exemplarily, the passivation and antireflection layer can include an alumina layer and a silicon nitride layer.

[0144] It should be noted that the execution order of the above-mentioned fifth and sixth steps can be interchanged. It can be to first form the second semiconductor layer located in the second region and extending to cover a part of the nitrogen-containing mask layer in the first region, and then form the above-mentioned passivation and antireflection layer. Or it can be to first form the above-mentioned passivation and antireflection layer, and then form the second semiconductor layer. When the passivation and antireflection layer includes a passivation layer and an antireflection layer, it can also be to first form the passivation layer, then form the second semiconductor layer, and then form the antireflection layer.

[0145] Step 7: As Figure 13 shown, form a transparent conductive layer 21 covering the sides of the first semiconductor layer 12 and the second semiconductor layer 19 facing away from the semiconductor substrate 11. Through isolation grooves are formed in the transparent conductive layer 21 to disconnect the part of the transparent conductive layer 21 corresponding to the first semiconductor layer 12 from the part of the transparent conductive layer 21 corresponding to the second semiconductor layer 19. Specifically, in the embodiments of the present invention, the material and thickness of the transparent conductive layer 21 and the width of the isolation grooves are not specifically limited, as long as they can be applied to the manufacturing method provided by the embodiments of the present invention. Secondly, the second semiconductor layer 19 corresponding to the isolation grooves can be removed or not removed.

[0146] Among them, the above-mentioned transparent conductive layer can be formed by processes such as physical vapor deposition, and then processes such as laser etching or etching with an etching slurry are used to open isolation grooves in the transparent conductive layer. Specifically, when etching with an etching slurry, the etching slurry can be printed first, and then the etching slurry is cured and etched. Next, the etching slurry needs to be cleaned. In addition, the setting position of the above-mentioned isolation grooves can be determined according to actual needs and manufacturing precision. Optionally, the isolation grooves can be provided in the region where the first semiconductor layer and the second semiconductor layer overlap along the thickness direction of the semiconductor substrate.

[0147] Of course, in some cases, the above-mentioned seventh-step operation may not be performed.

[0148] Step 8: As Figure 14 shown, form a first electrode 22 electrically connected to the first semiconductor layer 12 and form a second electrode 23 electrically connected to the second semiconductor layer 19.

[0149] Exemplarily, the above-mentioned first electrode and second electrode can be formed by processes such as screen printing and electroplating. Specifically, the materials of the first electrode and the second electrode can include any one of conductive materials such as silver, aluminum, copper, nickel, or titanium, as long as they can be applied to the manufacturing method provided by the embodiments of the present invention.

[0150] It should be noted that in the first-step operation, only the first semiconductor layer and the nitrogen-containing mask layer stacked in sequence can be formed on the semiconductor substrate. Or, as Figure 15As shown, it can also be that a first semiconductor layer 12, a surface passivation layer 20, and a nitrogen-containing mask layer 13 are sequentially formed and stacked on the semiconductor substrate 11. In this case, as Figure 16 shown, in the third step of the operation, it is necessary to use a first etching solution to remove the nitrogen-containing mask layer 13 located in the first laser irradiation area, as well as the surface passivation layer 20 and the first semiconductor layer 12 below the nitrogen-containing mask layer 13 located in the first laser irradiation area. In this case, through the manufacturing method provided by the embodiments of the present invention, under the protection of the part of the nitrogen-containing mask layer 13 that is not irradiated by the first laser, patterning of the first semiconductor layer 12 and the surface passivation layer 20 can be achieved, reducing the degree of thermal damage to the part of the semiconductor substrate 11 corresponding to the first laser irradiation area after patterning, and improving the yield of the manufactured solar cell.

[0151] Among them, the material of the above-mentioned surface passivation layer may include any passivating material such as silicon oxide, aluminum oxide, and intrinsic silicon, and no specific limitation is made here.

[0152] In addition, in some cases, after performing the above-mentioned fourth step of the operation and before performing the above-mentioned fifth step of the operation, a process such as wet etching can also be used to remove at least part of the nitrogen-containing mask layer that has not been irradiated by the first laser. Among them, in the case where all of the nitrogen-containing mask layer that has not been irradiated by the first laser is removed, in the overlapping area of the first semiconductor layer and the second semiconductor layer with opposite conduction types, the two can be electrically connected to form a diode structure with a lower reverse breakdown voltage, reducing the hot spot risk of the back contact battery. The removal range of the nitrogen-containing mask layer that has not been irradiated by the first laser can be determined according to the requirements for the anti-burning ability and conversion efficiency of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0153] Alternatively, the second semiconductor layer formed in the fifth step of the first embodiment can be spaced apart from the first semiconductor layer in a direction parallel to the first plane to reduce the leakage risk. In this case, the distance between the first semiconductor layer and the second semiconductor layer can be set according to actual needs, and no specific limitation is made here.

[0154] Embodiment 2

[0155] In this embodiment 2, only the steps that are different from those in the first embodiment are described in detail. For the same steps, reference can be made to the explanation in the above-mentioned first embodiment, and no further elaboration will be made in the second embodiment. The difference between the second embodiment and the first embodiment is that: in the second embodiment, between the fourth and fifth steps of the operation, the treatment of a part of the nitrogen-containing mask layer in the first area is added. And, in the second embodiment, at least part of the nitrogen-containing mask layer located in the overlapping area of the first semiconductor layer and the second semiconductor layer needs to be retained. The following is a detailed description of the second embodiment:

[0156] The first step: AsFigure 2 and Figure 3 As shown in Figure 3 , a first semiconductor layer 12 and a nitrogen-containing mask layer 13 are sequentially formed in a stacked manner on a semiconductor substrate 11.

[0157] Step 2: As Figures 4 to 6 shown, a part of the nitrogen-containing mask layer 13 is irradiated with a first laser, so that the nitrogen content in the first laser irradiation area 14 of the nitrogen-containing mask layer 13 is reduced.

[0158] Step 3: As Figure 7 shown, the nitrogen-containing mask layer 13 located in the first laser irradiation area is removed by using a first etching solution, and the first semiconductor layer 12 located under the nitrogen-containing mask layer 13 in the first laser irradiation area is removed.

[0159] Step 4: As Figure 8 shown, the surface of the area where the semiconductor substrate 11 is exposed outside the remaining nitrogen-containing mask layer 13 is polished and / or textured by using a first etching solution.

[0160] Among them, the operations in the first to fourth steps in the manufacturing method provided in the second embodiment are the same as those in the first to fourth steps in the manufacturing method provided in the first embodiment, and the description in the first embodiment above can be referred to, and will not be elaborated here. Alternatively, the second to fourth steps in the second embodiment can also be replaced by: directly removing a part of the nitrogen-containing mask layer by using a laser etching process; then, removing the part of the first semiconductor layer exposed outside the remaining nitrogen-containing mask layer by using a wet etching process or the like. Or, the second to fourth steps in the second embodiment can also be replaced by: directly removing a part of the nitrogen-containing mask layer and a part of the first semiconductor layer by using a laser etching process.

[0161] Step 5: As Figure 17 and Figure 18 shown, a part of the nitrogen-containing mask layer 13 in the non-edge area of the first area 16 is irradiated with a second laser, so that the nitrogen content in the second laser irradiation area 18 of the nitrogen-containing mask layer 13 is reduced.

[0162] Specifically, in the actual manufacturing process, when removing the first semiconductor layer under the nitrogen-containing mask layer in the first laser irradiation region, the etchant has side etching on the edge portion of the first semiconductor layer under the nitrogen-containing mask layer that is not irradiated by the first laser, so that the edge portion of the nitrogen-containing mask layer that is not irradiated by the first laser extends beyond the first semiconductor layer. In this case, if the second semiconductor layer is directly formed, the portion of the nitrogen-containing mask layer that extends beyond the first semiconductor layer will affect the coating of the second semiconductor layer on the sidewall of the first semiconductor layer, resulting in a relatively large number of defects at this location. The manufacturing method provided by the embodiments of the present invention uses a second laser to irradiate a part of the nitrogen-containing mask layer in the non-edge region of the first region, so that the nitrogen content in the second laser irradiation region of the nitrogen-containing mask layer is reduced, so that at least a part of the region of the nitrogen-containing mask layer irradiated by the second laser has high corrosion resistance to the second etchant, while the nitrogen content in the region of the nitrogen-containing mask layer that is not irradiated by the second laser is relatively high, resulting in relatively low corrosion resistance of this part to the second etchant. Therefore, the second etchant can be used to further selectively etch the nitrogen-containing mask layer, eliminate the influence of the portion of the nitrogen-containing mask layer that extends beyond the first semiconductor layer on the second semiconductor layer, improve the coating of the second semiconductor layer on the sidewall of the first semiconductor layer, and reduce the number of defects at this location. And at least a part of the nitrogen-containing mask layer remaining in the second laser irradiation region can be used as an insulating layer between the first semiconductor layer and the second semiconductor layer with opposite conductivity types, electrically isolating the two, reducing the leakage risk of the manufactured solar cell, and at the same time reducing the degree of thermal damage to the first semiconductor layer and the semiconductor substrate under the nitrogen-containing mask layer in the second laser irradiation region, improving the yield and working performance of the manufactured solar cell. In this case, the range of the second laser irradiation region can be determined according to the range requirement for the second semiconductor layer to extend and cover the first semiconductor layer in the actual application scenario, the range of the nitrogen-containing mask layer that extends beyond the first semiconductor layer after removing the first semiconductor layer under the nitrogen-containing mask layer in the first laser irradiation region, and the second laser irradiation accuracy, as long as it can be applied to the manufacturing method provided by the embodiments of the present invention.

[0163] As for the second laser irradiation conditions, and the reduction amplitude of the nitrogen content of the nitrogen-containing mask layer in the second laser irradiation region after the second laser irradiation can be determined according to actual needs, as long as it can be applied to the manufacturing method provided by the embodiments of the present invention.

[0164] Exemplarily, under the condition of the same laser wavelength and laser pulse width, the power density of the second laser can be less than that of the first laser. In this case, it can be prevented that due to the too high power density of the second laser, too much nitrogen element escapes from the part of the nitrogen-containing mask layer in the second laser irradiation area close to the first semiconductor layer, resulting in the loosening of its own structure, and it is ensured that at least the part of the nitrogen-containing mask layer close to the first semiconductor layer in the second laser irradiation area has high corrosion resistance to the second etching solution. Therefore, after removing the nitrogen-containing mask layer in the first area that is not irradiated by the second laser, at least the part of the nitrogen-containing mask layer close to the first semiconductor layer in the second laser irradiation area is retained, which is beneficial to reducing the leakage risk between the first semiconductor layer and the second semiconductor layer.

[0165] In addition, exemplarily, the second laser is used to irradiate a part of the nitrogen-containing mask layer in the non-edge area of the first area. Among them, the nitrogen-containing mask layer in the area not irradiated by the second laser includes an amorphous state, and at least part of the nitrogen-containing mask layer in the second laser irradiation area includes a crystalline state. In this case, the nitrogen-containing mask layer itself is in an amorphous state, and at least part of the nitrogen-containing mask layer in the second laser irradiation area forms a crystalline state after being irradiated by the second laser, which can change the corrosion resistance of at least part of the nitrogen-containing mask layer in the second laser irradiation area to different etching solutions. For example, it can enhance the corrosion resistance of at least part of the nitrogen-containing mask layer in the second laser irradiation area to etching solutions such as acid, thereby enhancing the structural stability of at least part of the nitrogen-containing mask layer in the second laser irradiation area, improving the reliability of the solar cell and prolonging its service life; and, when the nitrogen-containing mask layer also has a passivation effect, more nitrogen-containing mask layer can be retained after being etched by an etching solution such as acid, improving the passivation effect of the nitrogen-containing mask layer on the first semiconductor layer and reducing the carrier recombination rate.

[0166] Among them, the crystal phase, crystalline state type, distribution, size, etc. of different regions of the nitrogen-containing mask layer after being irradiated by the second laser can refer to the crystal phase, crystalline state type, distribution, size, etc. information of different regions of the nitrogen-containing mask layer in the first laser irradiation area after the second step operation in the previous embodiment one, and will not be elaborated here.

[0167] Specifically, the degree of crystallization and / or grain size in the nitrogen-containing mask layer after being irradiated by the second laser can be less than or equal to the degree of crystallization and / or grain size in the nitrogen-containing mask layer after being irradiated by the first laser. The application principle of the beneficial effects in this case can refer to the application principle of the beneficial effects that under the condition of the same laser wavelength and laser pulse width, the power density of the second laser can be less than that of the first laser, and will not be elaborated here.

[0168] In addition, exemplarily, an oxide layer may be formed on the surface of at least a part of the nitrogen-containing mask layer within the second laser irradiation region. In this case, the oxide layer of the insulating material generally has a passivation effect, which is beneficial to improving the passivation effect of the nitrogen-containing mask layer on the first semiconductor layer at the overlapping region and reducing the carrier recombination rate. Among them, information such as the material and thickness of the above oxide layer may refer to the material and thickness of the oxide layer formed after the second step operation in the previous embodiment one, which will not be elaborated here.

[0169] Specifically, the thickness of the oxide layer formed on the surface of the nitrogen-containing mask layer after the second laser irradiation may be less than or equal to the thickness of the oxide layer formed on the surface of the nitrogen-containing mask layer after the first laser irradiation. The application principle of the beneficial effect in this case may refer to the application principle of the beneficial effect that the power density of the second laser may be less than the power density of the first laser under the same laser wavelength and laser pulse width as described above, which will not be elaborated here.

[0170] When the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride, after the second laser irradiation, in the nitrogen-containing mask layer, the nitrogen-silicon ratio in the part located in the second laser irradiation region is less than that in the remaining part. This is beneficial to using the second etching solution to remove the nitrogen-containing mask layer that has not been irradiated by the second laser.

[0171] Sixth step: As Figure 19 shown, use the second etching solution to remove the nitrogen-containing mask layer 13 in the first region 16 that has not been irradiated by the second laser, and retain the nitrogen-containing mask layer 13 located in the second laser irradiation region 18.

[0172] Specifically, the type of the second etching solution may be determined according to the material of the nitrogen-containing mask layer and the difference in nitrogen content between the region of the nitrogen-containing mask layer in the first region that has not been irradiated by the second laser and the region that has been irradiated by the second laser, and no specific limitation is made here.

[0173] For example: when the material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride, the second etching solution may include acidic solutions such as hydrofluoric acid, nitric acid or sulfuric acid.

[0174] In addition, during the actual manufacturing process, after using the second etching solution to remove the nitrogen-containing mask layer in the first region that has not been irradiated by the second laser, it may be that all of the nitrogen-containing mask layer in the second laser irradiation region is retained. Or, as Figure 19As shown, it is also possible to thin the nitrogen-containing mask layer 13 located in the second laser irradiation region 18 while removing the nitrogen-containing mask layer 13 that is not irradiated by the second laser in the first region 16 using the second etching solution. In this case, on the premise of ensuring that the remaining nitrogen-containing mask layer 13 in the second laser irradiation region 18 after the thinning treatment can electrically isolate the first semiconductor layer 12 and the second semiconductor layer 19 with opposite conductivity types, there is no need to strictly limit the type of the second etching solution and / or the etching conditions in order to ensure that all of the nitrogen-containing mask layer 13 located in the second laser irradiation region 18 is retained, thereby reducing the process difficulty of removing the nitrogen-containing mask layer 13 that is not irradiated by the second laser in the first region 16 using the second etching solution. As for the thickness of the nitrogen-containing mask layer 13 located in the second laser irradiation region 18 removed by the thinning treatment, it can be determined according to the nitrogen content of the nitrogen-containing mask layer 13 in the second laser irradiation region 18 at different thicknesses after being irradiated by the second laser, and no specific limitation is made here.

[0175] Step 7: As Figure 20 and Figure 21 shown, form a second semiconductor layer 19 located in the second region 17 and extending to cover the nitrogen-containing mask layer 13 in the second laser irradiation region 18. The conductivity type of the second semiconductor layer 19 is opposite to that of the first semiconductor layer 12.

[0176] Step 8: As Figure 21 shown, use a process such as chemical vapor deposition to form a passivation and antireflection layer on one side of the second surface of the semiconductor substrate 11.

[0177] Step 9: As Figure 22 shown, form a transparent conductive layer 21 covering the sides of the first semiconductor layer 12 and the second semiconductor layer 19 facing away from the semiconductor substrate 11.

[0178] Step 10: As Figure 23 shown, form a first electrode 22 electrically connected to the first semiconductor layer 12 and form a second electrode 23 electrically connected to the second semiconductor layer 19.

[0179] Among them, the operations in Step 7 to Step 10 in the manufacturing method provided in the second embodiment are the same as the operations in Step 5 to Step 8 in the manufacturing method provided in the first embodiment, and the description in the first embodiment above can be referred to, and details are not repeated here.

[0180] Embodiment 3

[0181] Step 1: As Figure 24 and Figure 25 shown, sequentially form a stacked first semiconductor layer 12 and a nitrogen-containing mask layer 13 on the semiconductor substrate 11.

[0182] Specifically, in the embodiments of the present invention, the material of the semiconductor substrate is not specifically limited. The semiconductor substrate can be a substrate of any semiconductor material such as a silicon substrate, a silicon-germanium substrate, a germanium substrate, or a gallium arsenide substrate. In addition, the conduction type of the semiconductor substrate can be N-type, P-type, or intrinsic type. In addition, the semiconductor substrate has opposite first and second surfaces. Among them, the first surface can correspond to the front surface of the manufactured solar cell, and at this time, the second surface corresponds to the back surface of the manufactured solar cell. Based on this, the first semiconductor layer and the nitrogen-containing mask layer can be provided only on the first surface of the semiconductor substrate; or, the first semiconductor layer and the nitrogen-containing mask layer can also be provided only on the second surface of the semiconductor substrate; or, the first semiconductor layer and the nitrogen-containing mask layer can also be provided on the first and second surfaces of the semiconductor substrate. At this time, the conduction types of the two first semiconductor layers provided on the first and second surfaces are opposite.

[0183] For the above-mentioned first semiconductor layer, the material of the first semiconductor layer can include any semiconductor material such as silicon, silicon-germanium, germanium, or gallium arsenide. In terms of the arrangement form of the substance, the crystal phase of the first semiconductor layer can be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc.

[0184] In terms of the conduction type, when the first semiconductor layer is provided only on the first surface or the second surface, the conduction type of the first semiconductor layer can be N-type or P-type; at this time, the solar cell further includes a second semiconductor layer, and the conduction type of the second semiconductor layer is opposite to that of the first semiconductor layer. When the first semiconductor layer is provided on both the first and second surfaces of the semiconductor substrate, the conduction type of the first semiconductor layer provided on the first surface can be N-type, and at this time, the conduction type of the first semiconductor layer provided on the second surface is P-type; or, the conduction type of the first semiconductor layer provided on the first surface can be P-type, and at this time, the conduction type of the first semiconductor layer provided on the second surface is N-type.

[0185] For the nitrogen-containing mask layer, the information such as the material, thickness, and refractive index of the nitrogen-containing mask layer in Embodiment 3 can refer to the material, thickness, and refractive index of the nitrogen-containing mask layer in Embodiment 1 described above, and will not be elaborated here.

[0186] As for the process of sequentially forming the first semiconductor layer and the nitrogen-containing mask layer on the semiconductor substrate, it can refer to the manufacturing process of the first semiconductor layer and the nitrogen-containing mask layer in Embodiment 1 described above. Among them, if the first semiconductor layer and the nitrogen-containing mask layer are formed on both the first and second surfaces of the semiconductor substrate, the first semiconductor layer and the nitrogen-containing mask layer need to be formed on the first and second surfaces respectively through the above manufacturing process.

[0187] In terms of the formation range, the first semiconductor layer can be disposed over the entire area of the corresponding surface of the semiconductor substrate, or can also be disposed only over a partial area of the corresponding surface of the semiconductor substrate.

[0188] In addition, if the first semiconductor layer is only disposed over a partial area of the corresponding surface of the semiconductor substrate, after forming the first semiconductor layer disposed as a whole layer and before forming the nitrogen-containing mask layer, it is also necessary to pattern the first semiconductor layer. For example, processes such as chemical vapor deposition can be used to form a mask layer on the side of the first semiconductor layer facing away from the semiconductor substrate (the material of this mask layer can include materials such as silicon nitride, silicon oxide, or silicon oxynitride). Then, selective etching of the mask layer is performed by means of laser etching, chemical slurry etching, or a combination of photolithography and wet etching. Next, under the protection of the remaining mask layer, the first semiconductor layer is patterned. Then, the nitrogen-containing mask layer is formed in the manner of Embodiment 1.

[0189] Alternatively, when both the nitrogen-containing mask layer and the first semiconductor layer are disposed over a partial area of the corresponding surface of the semiconductor substrate, the entire nitrogen-containing mask layer and the first semiconductor layer can be patterned in the manner of the second step and the third step of Embodiment 1.

[0190] It should be noted that as Figure 24 shown, the first semiconductor layer 12 can be directly formed on the semiconductor substrate 11 by using the above manufacturing method. Or, as Figure 25 shown, before forming the first semiconductor layer 12, processes such as thermal oxidation or chemical vapor deposition can be used to first form a first interface passivation layer 24 on the semiconductor substrate 11, and then form the first semiconductor layer 12 on the first interface passivation layer 24. The material of the first interface passivation layer 24 can refer to the material of the first interface passivation layer 24 in Embodiment 1 described above, and will not be elaborated here.

[0191] Second step: As Figure 26 shown, a part of the nitrogen-containing mask layer 13 is irradiated with a first laser to reduce the nitrogen content in the first laser irradiation area 14 of the nitrogen-containing mask layer 13.

[0192] Among them, the area of the nitrogen-containing mask layer irradiated with the first laser corresponds to the contact area between the first semiconductor layer and the corresponding electrode. Therefore, the range of the nitrogen-containing mask layer irradiated with the first laser can be determined according to the contact pattern between the electrode and the first semiconductor layer. In addition, the crystal phase, the type, distribution, and size of the crystalline state, and the structural morphology, etc. of different areas of the nitrogen-containing mask layer after being irradiated with the first laser can refer to the information such as the crystal phase, the type, distribution, and size of the crystalline state, and the structural morphology, etc. of different areas of the nitrogen-containing mask layer located in the first laser irradiation area after the second step operation in Embodiment 1 described above, and will not be elaborated here.

[0193] Step 3: As Figure 27 shown, use the first etchant to remove the nitrogen-containing mask layer 13 located in the first laser irradiation area.

[0194] Among them, the operations of the second and third steps in the manufacturing method provided in Embodiment 3 are substantially the same as those in the second and third steps in the manufacturing method provided in Embodiment 1, and reference can be made to the description in Embodiment 1 above, which will not be elaborated here. The difference is that in the third step of Embodiment 3, only the nitrogen-containing mask layer located in the first laser irradiation area is removed by the first etchant, and the first semiconductor layer under the nitrogen-containing mask layer in the first laser irradiation area is not removed.

[0195] Step 4: As Figure 19 shown, use processes such as screen printing and electroplating to form the first electrode 22 on the part where the nitrogen-containing mask layer 13 has been removed by the first etchant. The first electrode 22 is electrically connected to the first semiconductor layer 12 through the conductive window formed after the nitrogen-containing mask layer 13 is irradiated by the first laser and etched by the first etchant.

[0196] It should be noted that in the first-step operation, only the first semiconductor layer and the nitrogen-containing mask layer stacked in sequence may be formed on the semiconductor substrate. Or, as Figure 29 shown, the first semiconductor layer 12, the surface passivation layer 20, and the nitrogen-containing mask layer 13 stacked in sequence may also be formed on the semiconductor substrate 11. In this case, as Figure 30 shown, in the third-step operation, it is necessary to use the first etchant to remove the nitrogen-containing mask layer 13 located in the first laser irradiation area and remove the surface passivation layer 20 under the nitrogen-containing mask layer 13 in the first laser irradiation area. In this case, through the manufacturing method provided in the embodiment of the present invention, under the protection of the part of the nitrogen-containing mask layer 13 that is not irradiated by the first laser, patterning of the surface passivation layer 20 can be realized, the degree of thermal damage to the part of the semiconductor substrate 11 corresponding to the first laser irradiation area after opening the conductive window can be reduced, and the yield of the manufactured solar cell can be improved.

[0197] Among them, the material of the above surface passivation layer may include any passivating material such as silicon oxide, aluminum oxide, and intrinsic silicon, and no specific limitation is made here.

[0198] In addition, in the third embodiment, if the manufactured solar cell further includes a second semiconductor layer (the second semiconductor layer has a conductivity type opposite to that of the first semiconductor layer, and the second semiconductor layer and the first semiconductor layer are disposed on opposite sides of the semiconductor substrate), the manufacturing method in the third embodiment further includes the step of forming the second semiconductor layer on a side of the semiconductor substrate facing away from the first semiconductor layer by using a process such as chemical vapor deposition. The formation method of the second semiconductor layer may refer to the manufacturing process of the first semiconductor layer described above, and will not be elaborated here. The order of the formation operation of the second semiconductor layer may be set according to actual requirements, and will not be specifically limited here.

[0199] Among them, as Figure 31 shown, the second semiconductor layer 19 may be directly formed on the semiconductor substrate 11 by using the above manufacturing method. Or, as Figure 32 shown, before forming the second semiconductor layer 19, a second interface passivation layer 25 may be first formed on the semiconductor substrate 11 by using a process such as thermal oxidation or chemical vapor deposition, and then the second semiconductor layer 19 may be formed on the second interface passivation layer 25. The material of the second interface passivation layer 25 may refer to the material of the second interface passivation layer 25 in the first embodiment described above, and will not be elaborated here.

[0200] In addition, when forming the second electrode electrically connected to the second semiconductor layer, the operations in the first to fourth steps in the third embodiment described above may be referred to, and will not be elaborated here.

[0201] Embodiment Four

[0202] In this embodiment four, only the steps different from those in the first embodiment will be described in detail. The same steps may refer to the explanation in the first embodiment above and will not be elaborated in the fourth embodiment. The difference between the fourth embodiment and the first embodiment is that after the third step operation, the fifth step operation in the first embodiment is not included. And, the first semiconductor layer in the fourth embodiment is a first doped polysilicon layer. The following is a detailed description of the fourth embodiment:

[0203] First step: As Figure 2 and Figure 3 shown, a first semiconductor layer 12 and a nitrogen-containing mask layer 13 are sequentially formed on the semiconductor substrate 11 in a stacked manner.

[0204] Second step: As Figures 4 to 6 shown, a part of the nitrogen-containing mask layer 13 is irradiated with a first laser to reduce the nitrogen content in the first laser irradiation area 14 of the nitrogen-containing mask layer 13.

[0205] Third step: As Figure 7As shown, a first etching solution is used to remove the nitrogen-containing mask layer 13 located in the first laser irradiation area and the first semiconductor layer 12 located below the nitrogen-containing mask layer 13 in the first laser irradiation area.

[0206] Among them, the operations in the first to third steps in the manufacturing method provided in the fourth embodiment are the same as those in the first to third steps in the manufacturing method provided in the first embodiment, and reference can be made to the description in the first embodiment above, which will not be elaborated here. After the third-step operation of the fourth embodiment, the remaining first semiconductor layer forms a poly-finger structure.

[0207] In this embodiment, in subsequent process steps, the nitrogen-containing mask layer can be completely removed, not removed, or partially removed.

[0208] Embodiment Five

[0209] The first step: As Figure 33 shown, a first semiconductor layer 12 and a nitrogen-containing mask layer 13 are sequentially formed in a stacked manner on the semiconductor substrate 11.

[0210] Here, for the explanations of the semiconductor substrate, as well as the materials, conductivity types, and crystal phases of the first semiconductor layer, reference can be made to the first embodiment above, which will not be elaborated here. In addition, the semiconductor substrate has opposite first and second surfaces. Among them, the first surface can correspond to the front surface of the manufactured solar cell, and at this time, the second surface corresponds to the back surface of the manufactured solar cell. As Figure 33 shown, the second surface has an alternatingly and spaced-apart first region and second region, as well as a third region 26 located between the first region and the second region. Based on this, the above-mentioned first semiconductor layer and nitrogen-containing mask layer are provided on the second surface of the semiconductor substrate.

[0211] For the nitrogen-containing mask layer, for the information such as the material, thickness, and refractive index of the nitrogen-containing mask layer in the fifth embodiment, reference can be made to the material, thickness, and refractive index of the nitrogen-containing mask layer in the first embodiment described above, which will not be elaborated here.

[0212] The second step: As Figure 34 shown, a part of the nitrogen-containing mask layer 13 is irradiated with a first laser to reduce the nitrogen content in the first laser irradiation area 14 of the nitrogen-containing mask layer 13.

[0213] Specifically, it is necessary to determine the irradiation range of the first laser according to the requirements for the range of the second semiconductor layer formed later in the actual application scenario and the anti-leakage requirements between the first semiconductor layer and the second semiconductor layer. For example: The first laser irradiation area can correspond to the second region and the third region of the second surface.

[0214] The third step: As Figure 35As shown, a first etching solution is used to remove the nitrogen-containing mask layer 13 located in the first laser irradiation area, and the first semiconductor layer 12 located under the nitrogen-containing mask layer 13 in the first laser irradiation area is removed.

[0215] Step 4: As Figure 35 and 36 shown, the surface of the semiconductor substrate 11 exposed outside the remaining nitrogen-containing mask layer 13 is polished and / or textured using the first etching solution.

[0216] Among them, the operations in the first to fourth steps of the manufacturing method provided in Example 5 are the same as those in the first to fourth steps of the manufacturing method provided in Example 1, and reference can be made to the description in the above Example 1, which will not be elaborated here.

[0217] Step 5: As Figure 37 and Figure 38 shown, a second semiconductor layer is formed on the second region 17. The conduction type of the second semiconductor layer 19 is opposite to that of the first semiconductor layer 12.

[0218] Specifically, the material of the second semiconductor layer may include any one of semiconductor materials such as polycrystalline silicon, single-crystalline silicon, amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

[0219] In the actual manufacturing process, exemplarily, a chemical vapor deposition process or the like can be used to form a second intrinsic semiconductor layer on the second region and the third region of the semiconductor substrate, and on the nitrogen-containing mask layer located in the first region. Then, a doping process such as diffusion, ion implantation, or doping source coating is used to dope the second intrinsic semiconductor layer so that the second intrinsic semiconductor layer forms a second semiconductor layer. Among them, if the material of the second semiconductor layer includes silicon and the second intrinsic semiconductor layer is doped using a diffusion process, a second doped silicon glass layer will also be formed on the side of the second semiconductor layer facing away from the semiconductor substrate after the second semiconductor layer is formed. In this case, a heat treatment can be performed on a part of the second doped silicon glass layer located in the first region and the third region by means of laser irradiation or the like so that the non-heat-treated part of the second doped silicon glass layer forms a mask layer; or, in the case of retaining the second doped silicon glass layer, a mask layer located on the second region is formed successively using processes such as deposition and selective etching (the material of this mask layer may include materials such as silicon nitride and / or aluminum oxide); or, the second doped silicon glass layer can also be removed, or in the case where the above second doped silicon glass layer is not formed, a mask layer covering the second region is formed successively using processes such as deposition and selective etching. Next, at least under the protection of the mask layer, the second semiconductor layer is patterned, and only the part of the second semiconductor layer located on the second region is retained.

[0220] Alternatively, the method of forming the first semiconductor layer and patterning the first semiconductor layer in the first to third steps can be adopted to form the second semiconductor layer and pattern the second semiconductor layer.

[0221] It should be noted that the order of the first to third steps can be interchanged with the order of the fifth step. In other words, the first semiconductor layer can be formed on the first region first, and then the second semiconductor layer located on the second region can be formed. Alternatively, the second semiconductor layer located on the second region can be formed first, and then the first semiconductor layer can be formed on the first region.

[0222] Step 6: As Figure 39 shown, a surface passivation layer covering the first semiconductor layer 12 and the second semiconductor layer 19 can be formed by processes such as chemical vapor deposition. The material of the surface passivation layer can include any passivating material such as silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, or intrinsic silicon, and no specific limitation is made here.

[0223] Step 7: As Figures 40 to 42 shown, a first electrode 22 electrically connected to the first semiconductor layer 12 through an opening in the surface passivation layer is formed, and a second electrode 23 electrically connected to the second semiconductor layer 19 through an opening in the surface passivation layer is formed.

[0224] Specifically, the materials of the first electrode and the second electrode can refer to the materials of the first electrode and the second electrode in the first embodiment described above, and no specific limitation is made here. As for the manufacturing process of the first electrode and the second electrode, as Figures 40 to 42 shown, when the surface passivation layer is a nitrogen-containing mask layer, openings corresponding to at least one of the first electrode 22 and the second electrode 23 can be formed on the nitrogen-containing mask layer in the manner of the second to fourth steps in the third embodiment, and the first electrode 22 and the second electrode 23 can be formed.

[0225] Alternatively, processes such as laser etching or etching with an etching paste can be used to open a through-conductive window in a film layer such as a nitrogen-containing mask layer covering the first semiconductor layer and / or the second semiconductor layer; then, processes such as screen printing and electroplating are used to form the above-mentioned first electrode and / or second electrode.

[0226] In the above description, technical details such as the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. with the desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not exactly the same as the methods described above. In addition, although the above embodiments are described separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination.

[0227] The embodiments of the present invention have been described above. However, these embodiments are merely for the purpose of illustration more clearly, rather than for limiting the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: A first semiconductor layer and a nitrogen-containing mask layer are sequentially formed in a stacked manner on a semiconductor substrate; irradiating a partial area of ​​the nitrogen-containing mask layer with a first laser so as to reduce the nitrogen content in the first laser irradiated area of ​​the nitrogen-containing mask layer; The nitrogen-containing mask layer located in the first laser irradiation area is removed by using a first etching solution.

2. The method for manufacturing a solar cell according to claim 1, characterized in that: In the nitrogen-containing mask layer, the corrosion resistance of the portion located in the first laser irradiation area to the first etching solution is lower than the corrosion resistance of the remaining portion to the first etching solution.

3. The method for manufacturing a solar cell according to claim 1, characterized in that: A hole structure is formed in a portion of the nitrogen-containing mask layer located in the first laser irradiation area.

4. The method for manufacturing a solar cell according to claim 3, characterized in that: The maximum pore size of at least one of the pore structures is greater than or equal to 5 nm and less than or equal to 20 μm; and / or, at least one of the hole structures is a through hole penetrating the nitrogen-containing mask layer; And / or, in at least one of the hole structures, the size of the hole opening on the side away from the first semiconductor layer is smaller than the size of the hole bottom on the side close to the first semiconductor layer; And / or, at least one of the hole structures is cylindrical, bowl-shaped or gourd-shaped.

5. The method for manufacturing a solar cell according to claim 1, characterized in that: The step of removing the nitrogen-containing mask layer located in the first laser irradiation area by using the first etching solution comprises: The first etching solution is used to remove the nitrogen-containing mask layer located in the first laser irradiation area and the first semiconductor layer below the nitrogen-containing mask layer located in the first laser irradiation area.

6. The method for manufacturing a solar cell according to claim 5, characterized in that: After removing the first semiconductor layer below the nitrogen-containing mask layer in the first laser irradiation area by using the first etching solution, the method for manufacturing a solar cell further includes: The first etching solution is used to perform a polishing process and / or a texturing process on the surface of the semiconductor substrate in the area exposed outside the remaining nitrogen-containing mask layer.

7. The method for manufacturing a solar cell according to any one of claims 1 to 6, characterized in that: The semiconductor substrate comprises first regions and second regions which are alternately arranged; the first laser irradiation region is the second region; After the first etching solution is used to remove the nitrogen-containing mask layer located in the first laser irradiation area, the method for manufacturing a solar cell further includes: removing the first semiconductor layer below the nitrogen-containing mask layer in the first laser irradiation area; irradiating a portion of the nitrogen-containing mask layer located in a non-edge region of the first region with a second laser so as to reduce the nitrogen content in the second laser irradiation region of the nitrogen-containing mask layer; Using a second etching solution to remove the nitrogen-containing mask layer in the first region that is not irradiated by the second laser, and retaining the nitrogen-containing mask layer in the region irradiated by the second laser; A second semiconductor layer is formed in the second region and extends to cover the nitrogen-containing mask layer in the second laser irradiation region; the second semiconductor layer and the first semiconductor layer have opposite conductivity types.

8. The method for manufacturing a solar cell according to claim 7, characterized in that: The step of removing the nitrogen-containing mask layer in the first region that is not irradiated by the second laser by using the second etching solution and retaining the nitrogen-containing mask layer in the region irradiated by the second laser comprises: The second etching solution is used to remove the nitrogen-containing mask layer in the first area that is not irradiated by the second laser, and the nitrogen-containing mask layer in the area irradiated by the second laser is thinned.

9. The method for manufacturing a solar cell according to claim 7, characterized in that: In the case of the same laser wavelength and laser pulse width, the power density of the second laser is smaller than the power density of the first laser.

10. The method for manufacturing a solar cell according to any one of claims 1 to 4, characterized in that: The method of sequentially forming a stacked first semiconductor layer and a nitrogen-containing mask layer on a semiconductor substrate comprises: sequentially forming a stacked first semiconductor layer, a surface passivation layer and a nitrogen-containing mask layer on a semiconductor substrate; The step of removing the first laser irradiation area by using the first etching solution includes: removing the nitrogen-containing mask layer located in the first laser irradiation area and the surface passivation layer below the nitrogen-containing mask layer located in the first laser irradiation area by using the first etching solution.

11. The method for manufacturing a solar cell according to any one of claims 1 to 4, characterized in that: After the nitrogen-containing mask layer located in the first laser irradiation area is removed by the first etching solution, the method for manufacturing a solar cell further includes: forming a first electrode at the portion of the nitrogen-containing mask layer removed by the first etching solution, wherein the first electrode is electrically connected to the first semiconductor layer.

12. The method for manufacturing a solar cell according to any one of claims 1 to 6, characterized in that: The semiconductor substrate comprises a first surface and a second surface opposite to each other; A first semiconductor layer and a nitrogen-containing mask layer are sequentially formed on a semiconductor substrate, comprising: Sequentially forming a first semiconductor layer and a nitrogen-containing mask layer stacked on a first surface of the semiconductor substrate, and forming the nitrogen-containing mask layer at an edge of a second surface of the semiconductor substrate; Using a third laser to irradiate the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate, so as to reduce the nitrogen content in the nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate; The nitrogen-containing mask layer located at the edge of the second surface of the semiconductor substrate is removed by using a third etching solution.

13. The method for manufacturing a solar cell according to claim 1, characterized in that: The material of the nitrogen-containing mask layer includes silicon nitride and / or silicon oxynitride; After the first laser irradiation, in the nitrogen-containing mask layer, the nitrogen-to-silicon ratio in the portion located in the first laser irradiation area is smaller than the nitrogen-to-silicon ratio in the remaining portion.

14. The method for manufacturing a solar cell according to claim 1, characterized in that: irradiating a partial area of ​​the nitrogen-containing mask layer with the first laser, wherein the nitrogen-containing mask layer in an area not irradiated by the first laser comprises an amorphous state, and at least a portion of the nitrogen-containing mask layer in an area irradiated by the first laser comprises a crystalline state; And / or, an oxide layer is formed on the surface of at least a portion of the nitrogen-containing mask layer located in the first laser irradiation area.

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