Method and equipment for preparing selective emitter of solar cell

Abstract

The present application discloses a method and equipment for preparing a selective emitter of a solar cell. The method for preparing a selective emitter of a solar cell comprises: preheating a preset area of ​​a semi-finished silicon wafer; locally heavily doping the diffusion layer of the semi-finished silicon wafer to form a heavily doped area, wherein the heavily doped area is located within the preset area, and the preset area is not smaller than the heavily doped area; wherein the local heavy doping is performed by laser irradiation. The method and equipment for preparing a selective emitter of a solar cell of the present application embodiment, by preheating a preset area of ​​a semi-finished silicon wafer, and then using a laser to locally heavily dope the diffusion layer of the semi-finished silicon wafer to form a heavily doped area, can reduce the damage of the laser to the surface of the silicon wafer during the production process of the laser-processed selective emitter solar cell, thereby improving the photoelectric conversion efficiency of the cell.

Description

Technical Field

[0001] The present application relates to the field of laser processing technology, and in particular to a method and equipment for preparing a selective emitter of a solar cell. Background Art

[0002] After the silicon wafer is textured and diffused, the selective emitter solar cell is locally heavily doped in the area where the grid line electrode is printed, which can reduce the contact resistance between the electrode and the silicon wafer and improve the photoelectric conversion efficiency of the battery. The existing method for preparing selective emitter solar cells usually uses slurry printing, and then adopts high-temperature diffusion, mask etching and other methods for preparation. Application CN101950780A discloses a method for making selective emitter cells by screen printing. This method involves two screen printings and one mask diffusion. The low production capacity is not conducive to large-scale production. Application CN101820023A discloses a method for preparing a selective emitter of a crystalline silicon solar cell. This method requires local heavy doping in a vacuum, and the process steps are complicated and the cost is extremely high. Application CN102709387A discloses a selective emitter etching process. This method uses a mask to achieve local heavy doping. The process is complicated, and it is difficult to ensure the alignment accuracy of the subsequent process. Application CN102110743A discloses a method for locally laser melting phosphosilicate glass to produce selective emitter solar cells. This method uses laser scanning on the phosphosilicate glass on the surface of a silicon wafer to achieve local heavy doping. The laser has the problem of uneven doping, and higher laser energy can also damage the silicon wafer. Summary of the invention

[0003] The purpose of this application is to solve one of the above-mentioned technical problems at least to a certain extent.

[0004] To this end, the first purpose of the present application is to propose a method for preparing a selective emitter of a solar cell, which can reduce the damage of the laser to the surface of the silicon wafer during the production process of the laser-processed selective emitter solar cell, thereby improving the photoelectric conversion efficiency of the cell.

[0005] The second objective of the present application is to provide a device for preparing a selective emitter of a solar cell.

[0006] In order to achieve the above-mentioned objectives, the first aspect embodiment of the present application proposes a method for preparing a selective emitter of a solar cell, comprising: preheating a preset area of ​​a semi-finished silicon wafer; locally heavily doping the diffusion layer of the semi-finished silicon wafer to form a heavily doped region, wherein the heavily doped region is located within the preset area, and the preset area is not smaller than the heavily doped region; wherein the local heavy doping is performed by laser irradiation.

[0007] Optionally, the surface of the diffusion layer is covered with phosphosilicate glass or borosilicate glass, and the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped region, including:

[0008] The diffusion layer is irradiated with laser light so that phosphorus atoms in the phosphosilicate glass or boron atoms in the borosilicate glass replace silicon atoms in the diffusion layer to form the heavily doped region.

[0009] Optionally, the preset area is the entire semi-finished silicon wafer;

[0010] Alternatively, the preset region is a strip-shaped region arranged corresponding to the heavily doped region, and the width of the preset region is not less than the width of the heavily doped region.

[0011] Optionally, the preheating treatment is one of heating by a heating plate, heating by a heating chamber, heating by an LED lamp or an infrared lamp tube, and heating by a laser.

[0012] Optionally, a preheating treatment is performed on a predetermined area of ​​the semi-finished silicon wafer, including:

[0013] When the preset region is a strip-shaped region arranged corresponding to the heavily doped region, a laser heating method is used to heat the preset region.

[0014] Optionally, irradiating the diffusion layer with laser comprises:

[0015] irradiating the diffusion layer with the light spot emitted by the laser, and scanning the heavily doped region of the entire diffusion layer; or

[0016] The light spot emitted by the laser is used to illuminate the diffusion layer, and the semi-finished silicon wafer is controlled to move along a preset direction so that the laser scans through the heavily doped region of the entire diffusion layer.

[0017] Optionally, the shape of the light spot emitted by the laser is one of circular, elliptical, rectangular and square.

[0018] Optionally, when the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped region, the wavelength of the laser used is 355-1500nm and the energy density is 0.2-2.0J / cm 2 .

[0019] Optionally, when the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped region, the wavelength of the laser used is 800-1500 nm.

[0020] Optionally, the method further includes:

[0021] After the preheating treatment is performed on the preset area of ​​the semi-finished silicon wafer, the preset area is subjected to a heat preservation treatment.

[0022] The method for preparing the selective emitter of a solar cell in the embodiment of the present application preheats a preset area of ​​a semi-finished silicon wafer, and then uses a laser to locally heavily dope the diffusion layer of the semi-finished silicon wafer to form a heavily doped area. This can reduce the damage to the surface of the silicon wafer caused by the laser during the production of the laser-processed selective emitter solar cell, thereby improving the photoelectric conversion efficiency of the battery.

[0023] In order to achieve the above-mentioned purpose, the second embodiment of the present application proposes a preparation device for a solar cell selective emitter, comprising: a pretreatment device, a laser processing device and a workbench,

[0024] Wherein, the pretreatment device is used to perform preheating treatment on a preset area of ​​the semi-finished silicon wafer;

[0025] The laser processing device is used to perform local heavy doping on the diffusion layer of the preheated semi-finished silicon wafer to form a heavily doped area, wherein the heavily doped area is located in the preset area, and the preset area is not smaller than the heavily doped area, and the local heavy doping is performed by laser irradiation;

[0026] The workbench is used for placing the semi-finished silicon wafer.

[0027] Optionally, the pretreatment device is one of a heating table, a heating chamber, an LED lamp or an infrared lamp tube heating device, and a laser heating device.

[0028] Optionally, the laser processing device is arranged above the workbench, and the pretreatment device is arranged above, below or around the workbench.

[0029] Optionally, the pre-processing device includes a first laser generator, the first laser generator generates a first laser to form a first light spot on the diffusion layer, and the first light spot covers the diffusion layer; or,

[0030] The pre-processing device includes a first laser generator and a first focusing component. The first laser generator generates a first laser. The first laser passes through the first focusing component to form a first light spot on the diffusion layer. The first light spot covers the diffusion layer.

[0031] Optionally, when the first light spot does not cover the entire diffusion layer, the pre-processing device further includes a laser scanning component,

[0032] The laser scanning component controls the movement of the first laser so that the first light spot passes through the entire diffusion layer; or

[0033] The equipment for preparing the selective emitter of a solar cell further comprises a first moving device, and the first moving device is used for driving the semi-finished silicon wafer to move so that the first light spot passes through the entire diffusion layer.

[0034] Optionally, the workbench includes a fixing device, and the fixing device is used to fix the semi-finished silicon wafer on the workbench.

[0035] Optionally, the laser processing device includes a second laser generator and a second scanning and focusing component, the second laser generator generates a second laser, the second laser passes through the second scanning and focusing component to form a second light spot on the diffusion layer, and the second scanning and focusing component controls the second light spot to scan through the entire diffusion layer.

[0036] Optionally, the second scanning and focusing component is a galvanometer and a field lens, and the galvanometer and the field lens control the optical path of the second laser so that the second light spot scans along the diffusion layer;

[0037] Or the second scanning and focusing component is a focusing mirror and a linear motor, the focusing mirror controls the second light spot of the second laser to focus on the diffusion layer, and the linear motor drives the laser processing device to scan along the diffusion layer, or drives the workbench to move relative to the second light spot.

[0038] Optionally, the laser processing device further includes an optical shaping device,

[0039] The optical shaping device controls the second laser to form at least one third light spot of a specific shape on the diffusion layer, so that the third light spot irradiates a partial area or the entire area of ​​the diffusion layer.

[0040] The equipment for preparing the selective emitter of a solar cell in the embodiment of the present application preheats a preset area of ​​a semi-finished silicon wafer through a pretreatment device, and then a laser processing device uses a laser to locally heavily dope the diffusion layer of the preheated semi-finished silicon wafer to form a heavily doped area, which can reduce the damage to the surface of the silicon wafer caused by the laser during the production process of the laser processed selective emitter solar cell, thereby improving the photoelectric conversion efficiency of the battery.

[0041] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0043] Figure 1 is a flow chart of a method for preparing a selective emitter of a solar cell according to an embodiment of the present application;

[0044] Figure 2 is a flow chart of a method for preparing a selective emitter of a solar cell according to another embodiment of the present application;

[0045] Figure 3 It is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to an embodiment of the present application;

[0046] Figure 4 is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to another embodiment of the present application;

[0047] Figure 5 It is a structural schematic diagram of a device for preparing a selective emitter of a solar cell according to a specific embodiment of the present application;

[0048] Figure 6 is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to another specific embodiment of the present application;

[0049] Figure 7 It is a structural schematic diagram of a device for preparing a selective emitter of a solar cell according to another embodiment of the present application;

[0050] Figure 8 It is a structural schematic diagram of a device for preparing a selective emitter of a solar cell according to another specific embodiment of the present application;

[0051] Fig. 9 is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to another specific embodiment of the present application;

[0052] Fig.10 is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to another embodiment of the present application;

[0053] Fig.11 It is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to an embodiment of the present application;

[0054] Fig.12 It is a schematic structural diagram of a device for preparing a selective emitter of a solar cell according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0056] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0057] The following describes a method and equipment for preparing a selective emitter for a solar cell according to an embodiment of the present application with reference to the accompanying drawings.

[0058] The preparation principle is as follows: When processing solar cells, a layer of phosphosilicate glass or borosilicate glass will be formed on the surface of the silicon wafer after texturing and diffusion. The phosphorus atoms in the phosphosilicate glass or the boron atoms in the borosilicate glass are used as diffusion sources. The phosphorus atoms or boron atoms are activated through preheating treatment, and then lasers are used to propel them so that they diffuse to a certain depth in the silicon wafer to form a PN junction, thereby achieving local heavy doping. Since the pulse energy required for doping is low and the laser repetition frequency used is high, the processing speed can be increased and the production capacity of the equipment can be improved. On the other hand, lower laser energy can reduce the damage to the surface of the silicon wafer by laser processing and improve the photoelectric conversion efficiency of the battery.

[0059] Figure 1 It is a flow chart of a method for preparing a selective emitter of a solar cell according to an embodiment of the present application.

[0060] like Figure 1 As shown, the method for preparing a selective emitter of a solar cell comprises:

[0061] S1, preheating a preset area of ​​the semi-finished silicon wafer.

[0062] Among them, the semi-finished silicon wafer refers to a semi-finished silicon wafer that has been textured (or not textured) and diffused, and a layer of phosphosilicate glass or borosilicate glass is formed on the surface of the diffusion layer.

[0063] Before processing the semi-finished silicon wafer, a preheating treatment may be performed, wherein the preheating treatment may be performed in a variety of ways, such as heating with a heating plate, heating with a heating chamber, heating with an LED lamp or an infrared lamp tube, or heating with a laser.

[0064] By preheating the semi-finished silicon wafer, specifically, the preheating temperature is 50-500°C, preferably 150-300°C, the phosphorus atoms in the phosphorus silicate glass on the diffusion layer or the boron atoms in the borosilicate glass can obtain a certain initial thermal motion speed, which is beneficial to further advance the phosphorus atoms or boron atoms in the subsequent steps.

[0065] S2, locally heavily doping the diffusion layer of the semi-finished silicon wafer to form a heavily doped region.

[0066] After the preheating treatment, the diffusion layer of the semi-finished silicon wafer may be locally heavily doped by laser irradiation to form a heavily doped region.

[0067] Specifically, the surface of the diffusion layer of the semi-finished silicon wafer is covered with phosphosilicate glass or borosilicate glass. The diffusion layer can be irradiated with laser. Since phosphorus atoms or boron atoms have a certain initial thermal motion speed, laser propulsion is performed in this step, so that the phosphorus atoms in the phosphosilicate glass or the boron atoms in the borosilicate glass replace the silicon atoms in the diffusion layer to form a heavily doped area.

[0068] The heavily doped region is located in a preset area, and the preset area is not smaller than the heavily doped region.

[0069] The preset area can be the entire semi-finished silicon wafer, or it can be a strip area corresponding to the heavily doped area. The width of the preset area is not less than the width of the heavily doped area, so as to achieve the purpose of saving energy.

[0070] In one embodiment of the present application, when the preset region is a strip-shaped region arranged corresponding to the heavily doped region, a laser heating method is preferably used to heat the preset region.

[0071] The diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped area. Specifically, the following two methods may be used:

[0072] The first method is to use the laser spot to illuminate the diffusion layer and scan the heavily doped area of ​​the entire diffusion layer. In other words, the semi-finished silicon wafer is kept fixed and the entire diffusion layer is scanned by adjusting the optical path of the laser. For example, the optical path scanning path is adjusted by using a galvanometer scanning or by moving the entire laser device relative to the semi-finished silicon wafer.

[0073] The second method is to use the laser spot to illuminate the diffusion layer, and control the semi-finished silicon wafer to move in a preset direction, so that the laser scans through the heavily doped area of ​​the entire diffusion layer. In other words, the laser light path remains unchanged, and the entire diffusion layer is scanned by moving the semi-finished silicon wafer.

[0074] The light spot irradiated by the laser may include various shapes, such as circular, elliptical, rectangular, square, etc. Preferably, the light spot is square or rectangular, which has better light spot uniformity and better doping effect.

[0075] When the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped area, the wavelength of the laser used is 355-1500nm and the energy density is 0.2-2.0J / cm 2 Preferably, the wavelength of the laser is 800-1500 nm.

[0076] In another embodiment of the present application, Figure 2 As shown, the method for preparing the selective emitter of a solar cell also includes:

[0077] S3, after preheating the preset area of ​​the semi-finished silicon wafer, heat preservation treatment is performed on the preset area.

[0078] Normally, the time interval between preheating and local heavy doping is very small, and heat preservation is not required. However, heat preservation is beneficial to maintain the initial thermal motion speed of phosphorus atoms or boron atoms, thereby ensuring the effect of subsequent processing. Heat preservation can be carried out by continuing heating (temperature control) using a preheating device.

[0079] The method for preparing the selective emitter of a solar cell in the embodiment of the present application preheats a preset area of ​​a semi-finished silicon wafer, and then uses a laser to locally heavily dope the diffusion layer of the semi-finished silicon wafer to form a heavily doped area. This can reduce the damage to the surface of the silicon wafer caused by the laser during the production of the laser-processed selective emitter solar cell, thereby improving the photoelectric conversion efficiency of the battery.

[0080] Several specific embodiments are described in detail below.

[0081] Embodiment 1:

[0082] The method for preparing a selective emitter of a solar cell includes a pretreatment stage and a heavy doping stage.

[0083] In the pretreatment stage, the entire semi-finished silicon wafer is preheated by heating the heating table, heating chamber or infrared lamp tube, so that the phosphorus atoms in the phosphosilicate glass or the boron atoms in the borosilicate glass obtain a certain initial thermal motion speed. In the heavy doping stage, the semi-finished silicon wafer (corresponding to the position of the heavy doping area) is irradiated with a laser to push the phosphorus atoms of the phosphosilicate glass activated by pretreatment or the boron atoms in the borosilicate glass into the surface of the silicon wafer. After solidification, the phosphorus atoms or boron atoms replace the position of the silicon atoms to form a heavy doping area. The laser wavelength used for heavy doping is 355-1500nm, preferably 515-545nm, and the scanning speed can be selected according to actual needs. The laser spot can be circular, elliptical, square or rectangular, etc. Preferably it is square or rectangular, with better spot uniformity and better doping effect.

[0084] The invention discloses a preparation device for a selective emitter of a solar cell, comprising a heating device, a laser processing device and a workbench.

[0085] The semi-finished silicon wafer is placed on a workbench, the laser processing device is arranged above the workbench, and the heating device is a heating table, a heating chamber or an infrared lamp. Among them, the heating table can be realized by arranging heating components such as a heating rod on the workbench, and the placement and heating of the semi-finished silicon wafer can be realized at the same time. The heating chamber and the infrared lamp can be arranged near the workbench, for example, below, above or around the workbench, so as to achieve the heating of the entire semi-finished silicon wafer. The laser processing device includes a laser generator, a galvanometer and a field mirror. The laser generator emits a laser, which passes through the galvanometer and the field mirror to form a light spot in the heavily doped area of ​​the semi-finished silicon wafer. The galvanometer drives the laser to scan along the heavily doped area path to complete the scanning of the entire heavily doped area. Preferably, it also includes a laser shaping component to shape the laser light spot into an ellipse, a square or a rectangle.

[0086] Embodiment 2:

[0087] The method in this embodiment is different from that in Embodiment 1 only in that laser heating is used during pretreatment, and the laser covers the entire semi-finished silicon wafer to complete the pretreatment of the silicon wafer.

[0088] The corresponding preparation equipment of the selective emitter of the solar cell is different from the preparation equipment in Example 1 only in that the heating device is a laser heating device. The laser heating device includes a laser generator, and may further include a laser shaping component and a laser focusing component, and a light spot of a preset shape is formed by the laser shaping component. The laser heating device can be arranged above the workbench and does not affect the laser processing device.

[0089] Example 3

[0090] The method in this embodiment is different from that in Embodiment 2 only in that during pretreatment, the area irradiated by the laser spot coincides with or is slightly wider than the heavily doped area. The heavily doped area is in the shape of a strip. Preferably, the width of the laser spot irradiated by the laser heating device is 1.2 to 3 times the width of the strip (single strip). The laser of the laser heating device is shaped by a shaping device into a strip-shaped spot of the same shape as the aforementioned irradiated area to complete the heating. The preheating area is more concentrated, which avoids energy waste and helps to improve the doping effect.

[0091] Example 4

[0092] The method in this embodiment is similar to that in Embodiment 3, except that during processing, the spot width of the heating laser is equal to or greater than the width of the heavily doped region (single line), preferably 1.2 to 3 times its width, the spot width of the processing laser is equal to the width of the heavily doped region (single line), the heating laser and the processing laser scan through the entire heavily doped region path, the two have the same scanning trajectory, and the heating laser is irradiated before the processing laser. The laser heating device is arranged above the workbench and does not affect the laser processing device.

[0093] The difference between the equipment for preparing the selective emitter of a solar cell in this embodiment and the equipment for preparing in Embodiment 1 is that the laser heating device is the same as the laser processing device in Embodiment 1.

[0094] Example 5

[0095] The method in this embodiment is different from that in Embodiment 1 and Embodiment 4 only in that during heavy doping (and) or preheating treatment, the laser processing device (and) laser heating device and the workbench are relatively moved to realize scanning of the entire preset area by the light spot.

[0096] The corresponding preparation equipment is different from the equipment in Examples 1 and 4 in that:

[0097] The laser processing device includes a laser and a field lens, and may also include an optical path transmission device, a beam expansion device, etc.

[0098] The laser heating device includes a laser and a field lens, and may also include an optical path transmission device, a beam expansion device, etc.

[0099] The laser heating device is arranged in front of the laser processing device, so that when the laser heating device moves relative to the workbench, the laser heating device is always in front of the laser processing device.

[0100] The preparation equipment also includes a moving device for driving the workbench to move. By setting a linear motion mechanism or an XY linear motion mechanism on the workbench, the semi-finished silicon wafer on the workbench is driven to move to the corresponding area to complete the scanning.

[0101] When the shape of the preset area is a plurality of parallel strips, the workbench may be a conveyor belt. The semi-finished silicon wafer is placed on the conveyor belt, and the heating table is arranged below the conveyor belt. The movement of the semi-finished silicon wafer is controlled by conveying, thereby improving the processing and conveying efficiency.

[0102] The preparation equipment may also include a moving device that drives the laser processing device (and) the laser heating device to move as a whole, and the scanning is completed by controlling the overall movement of the laser processing device (and) the laser heating device.

[0103] In order to implement the above-mentioned embodiment, the present application also proposes a device for preparing a selective emitter of a solar cell.

[0104] like Figure 3 As shown, the manufacturing equipment of the selective emitter of a solar cell includes a pre-processing device 100 , a laser processing device 200 and a workbench 300 .

[0105] The laser processing device 200 is disposed above the workbench 300 , and the pre-processing device 100 is disposed near the workbench, such as above, below, or around the workbench.

[0106] The pretreatment device 100 is used to perform preheating treatment on a preset area of ​​a semi-finished silicon wafer.

[0107] The pre-treatment device 100 may be one of a heating table, a heating chamber, an LED lamp or an infrared lamp tube heating device, and a laser heating device. The heating table, the heating chamber, and the LED lamp or infrared lamp tube heating device may be set with reference to the heating table, the heating chamber, and the LED lamp or infrared lamp tube heating device of the prior art to heat the semi-finished silicon wafer placed on the workbench. Specifically, the pre-treatment device 100 is a laser heating device, which includes a first laser generator 110.

[0108] The first laser generator 110 generates a first laser to form a first light spot on the diffusion layer of the semi-finished silicon wafer. The first light spot covers the diffusion layer.

[0109] like Figure 4 As shown, the pre-processing device 100 further includes a first focusing component 120. The first laser generator 110 generates a first laser, and the first laser passes through the first focusing component 120 to form a first light spot on the diffusion layer, and the first light spot covers the diffusion layer of the semi-finished silicon wafer.

[0110] In one embodiment of the present application, Figure 5 As shown, the pre-processing device 100 further includes a laser scanning component 130 .

[0111] When the first light spot does not cover the entire diffusion layer, the laser scanning component 130 controls the movement of the first laser so that the first light spot passes through a preset area of ​​the entire diffusion layer. The laser scanning component 130 can be a galvanometer or a linear motor. The galvanometer can control the deflection of the light path, and the linear motor can drive the laser heating device to move and scan the preset area.

[0112] In another embodiment of the present application, Figure 6 As shown, the manufacturing equipment for the selective emitter of a solar cell further includes a first moving device 400 .

[0113] The first moving device 400 is used to drive the semi-finished silicon wafer to move so that the first light spot passes through the entire diffusion layer.

[0114] The laser processing device 200 is used to perform local heavy doping on the diffusion layer of the semi-finished silicon wafer to form a heavy doping area. The local heavy doping is performed by laser irradiation.

[0115] The heavily doped region is located in a preset area, and the preset area is not smaller than the heavily doped region.

[0116] Specifically, Figure 7 As shown, the laser processing device 200 includes a second laser generator 210 and a second scanning focusing component 220 .

[0117] The second laser generator 210 generates a second laser, and the second laser forms a second light spot on the diffusion layer through the second scanning and focusing component 220. The second focusing component 220 controls the second light spot to scan through the heavily doped region of the entire diffusion layer.

[0118] In one embodiment of the present application, Figure 8 As shown, the second scanning and focusing component 220 is a galvanometer 221 and a field lens 222. The galvanometer 221 and the field lens 222 control the optical path of the second laser so that the second light spot scans along the heavily doped region path of the diffusion layer.

[0119] In another embodiment of the present application, Fig. 9 As shown, the second scanning focusing component 220 is a focusing mirror 223 and a linear motor 224. The focusing mirror 223 controls the second light spot of the second laser to focus on the diffusion layer to form a second light spot, and the linear motor 224 drives the laser processing device 200 to scan along the heavily doped region path of the diffusion layer.

[0120] The workbench 300 is used to place semi-finished silicon wafers.

[0121] like Fig.10 As shown, the workbench 300 may include a fixing device 310, and the fixing device 310 is used to fix the semi-finished silicon wafer on the workbench 300. For example, the fixing device 310 may be a negative pressure adsorption device, which adsorbs the semi-finished silicon wafer through adsorption force to achieve better fixation.

[0122] In another embodiment of the present application, Fig.11 As shown, the second scanning and focusing component 220 is a focusing mirror 223 and a linear motor 224. The linear motor 224 is used to drive the workbench to move so that the second light spot passes through the heavily doped region of the entire diffusion layer.

[0123] In yet another embodiment of the present application, Fig.12 As shown, the equipment for preparing the selective emitter of a solar cell further includes an optical shaping device 500 .

[0124] The optical shaping device 500 controls the second laser to form at least one third light spot of a specific shape in the diffusion layer, such as a rectangular or square light spot, so as to make the heavy doping more uniform.

[0125] (and), control the second laser to form at least one fourth light spot of a specific shape in the diffusion layer. For example, the fourth light spot can be a plurality of strip-shaped light spots to form a preset area of ​​the same shape, directly irradiating the preset area for heating. Or form a rectangular or square light spot and scan along the path of the preset area.

[0126] The equipment for preparing the selective emitter of a solar cell in the embodiment of the present application preheats a preset area of ​​a semi-finished silicon wafer through a pretreatment device, and then a laser processing device uses a laser to locally heavily dope the diffusion layer of the semi-finished silicon wafer to form a heavily doped area. This can reduce the damage to the surface of the silicon wafer caused by the laser during the production process of the laser processed selective emitter solar cell, thereby improving the photoelectric conversion efficiency of the battery.

[0127] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0128] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing in a suitable manner if necessary, and then stored in a computer memory.

[0129] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0130] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Claims

1. A method for preparing a selective emitter of a solar cell, characterized in that: include: Preheating a preset area of ​​the semi-finished silicon wafer, when the preset area is a strip-shaped area corresponding to the heavily doped area, heating the preset area by a laser heating method; Performing local heavy doping on the diffusion layer of the semi-finished silicon wafer to form a heavily doped region, wherein the heavily doped region is located in the preset region, and the preset region is not smaller than the heavily doped region; Wherein, the local heavy doping is performed by laser irradiation; The preheating temperature of the laser heating the preset area is 150-300°C; When the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped area, the wavelength of the laser used is 355-1500nm and the energy density is 0.2-2.0J / cm 2 ; The surface of the diffusion layer is covered with phosphosilicate glass or borosilicate glass, and the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped area, including: The diffusion layer is irradiated with laser light so that phosphorus atoms in the phosphosilicate glass or boron atoms in the borosilicate glass replace silicon atoms in the diffusion layer to form the heavily doped region.

2. The method according to claim 1, characterized in that The width of the preset region is not less than the width of the heavily doped region.

3. The method according to claim 1, characterized in that The method further comprises: irradiating the diffusion layer with a laser, comprising: irradiating the diffusion layer with the light spot emitted by the laser, and scanning the heavily doped region of the entire diffusion layer; or The light spot emitted by the laser is used to illuminate the diffusion layer, and the semi-finished silicon wafer is controlled to move along a preset direction so that the laser scans through the heavily doped region of the entire diffusion layer.

4. The method according to claim 3, characterized in that The shape of the light spot emitted by the laser is one of circular, elliptical, rectangular and square.

5. The method according to claim 1, characterized in that When the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped region, the wavelength of the laser used is 800-1500nm.

6. The method according to claim 1, characterized in that Also includes: After the preheating treatment is performed on the preset area of ​​the semi-finished silicon wafer, the preset area is subjected to a heat preservation treatment.

7. A device for preparing a selective emitter of a solar cell, characterized in that: include: Pre-treatment device, laser processing device and workbench, Wherein, the pretreatment device is used to preheat the preset area of ​​the semi-finished silicon wafer, and the pretreatment device is a laser heating device. When the preset area is a strip-shaped area corresponding to the heavily doped area, the preset area is heated by a laser heating method; The laser processing device is used to perform local heavy doping on the diffusion layer of the preheated semi-finished silicon wafer to form a heavily doped area, wherein the heavily doped area is located in the preset area, and the preset area is not smaller than the heavily doped area, and the local heavy doping is performed by laser irradiation; The workbench is used to place the semi-finished silicon wafer; The preheating temperature of the laser heating the preset area is 150-300°C; When the diffusion layer of the semi-finished silicon wafer is locally heavily doped to form a heavily doped area, the wavelength of the laser used is 355-1500nm and the energy density is 0.2-2.0J / cm 2 ; The surface of the diffusion layer is covered with phosphosilicate glass or borosilicate glass, and the diffusion layer is irradiated with laser so that phosphorus atoms in the phosphosilicate glass or boron atoms in the borosilicate glass replace the silicon atoms in the diffusion layer to form the heavily doped region.

8. The device for preparing a selective emitter of a solar cell according to claim 7, characterized in that: The laser processing device is arranged above the workbench, and the pre-processing device is arranged above, below or around the workbench.

9. The preparation device for the selective emitter of a solar cell according to claim 7, characterized in that: The pre-processing device comprises a first laser generator, the first laser generator generates a first laser to form a first light spot on the diffusion layer, and the first light spot covers the diffusion layer; or, The pre-processing device includes a first laser generator and a first focusing component. The first laser generator generates a first laser. The first laser passes through the first focusing component to form a first light spot on the diffusion layer. The first light spot covers the diffusion layer.

10. The manufacturing device for the selective emitter of a solar cell according to claim 9, characterized in that: When the first light spot does not cover the entire diffusion layer, the pre-processing device further includes a laser scanning component, which controls the movement of the first laser so that the first light spot passes through the entire diffusion layer; Alternatively, the equipment for preparing the selective emitter of a solar cell further comprises a first moving device, and the first moving device is used for driving the semi-finished silicon wafer to move so that the first light spot passes through the entire diffusion layer.

11. The manufacturing device of the solar cell selective emitter according to claim 7, characterized in that: The workbench comprises a fixing device, and the fixing device is used to fix the semi-finished silicon wafer on the workbench.

12. The manufacturing device for the selective emitter of a solar cell according to claim 7, characterized in that: The laser processing device includes a second laser generator and a second scanning and focusing component. The second laser generator generates a second laser. The second laser passes through the second scanning and focusing component to form a second light spot on the diffusion layer. The second scanning and focusing component controls the second light spot to scan through the entire diffusion layer.

13. The manufacturing device of the solar cell selective emitter according to claim 12, characterized in that: The second scanning and focusing component is a galvanometer and a field lens, and the galvanometer and the field lens control the optical path of the second laser so that the second light spot scans along the diffusion layer; Or the second scanning and focusing component is a focusing mirror and a linear motor, the focusing mirror controls the second light spot of the second laser to focus on the diffusion layer, and the linear motor drives the laser processing device to scan along the diffusion layer, or drives the workbench to move relative to the second light spot.

14. The manufacturing device for the selective emitter of a solar cell according to claim 12, characterized in that: The laser processing device also includes an optical shaping device, The optical shaping device controls the second laser to form at least one third light spot of a specific shape on the diffusion layer, so that the third light spot irradiates a partial area or the entire area of ​​the diffusion layer.

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