CN117374137A - Substrate processing method and solar cell manufacturing method - Google Patents

Abstract

The present application provides a substrate processing method comprising providing a substrate comprising a first surface; performing localized oxidation on the first surface of the substrate, thereby forming a first region including an oxide layer and a second region not including an oxide layer on the first surface; and (3) entering the substrate into the alkali solution for a preset time period to perform texturing, so that a first suede structure is formed on a first area of the first surface, and a second suede structure is formed on a second area of the first surface, wherein the size of the first suede structure is smaller than that of the second suede structure. Thereby, different sized pile structures can be obtained on the surface of the substrate by a simple process. Therefore, by forming a large-size suede structure in the metal grid line area, the adhesive force of the metal grid line and the matrix can be improved, and the organic balance of the grid line adhesive force and the anti-reflection effect of the surface of the battery piece is realized, so that the method has good process controllability.

Description

Substrate processing method and solar cell manufacturing method

Technical field

The present application relates to a substrate processing method, and in particular to a method of processing a substrate during the manufacturing of solar cell wafers.

Background technique

In the wafer preparation process for solar cells, a texturing step is usually required. Texturing is to form a textured surface on the surface of the substrate. The textured surface will reflect and refract the light multiple times, thereby changing the light transmission path and allowing the light to enter the battery. Texturing can reduce the reflection of sunlight on the battery surface and increase light absorption, thereby improving the battery's utilization of sunlight and battery conversion efficiency.

Generally, the larger the texture on the surface of the silicon wafer, the greater the reflectivity of the battery to light, and the better the adhesion between the metal grid and the surface of the battery. On the contrary, if the texture on the surface of the battery is smaller, the greater the reflectivity of the battery to light. The smaller the reflectivity, the worse the bonding force between the metal grid and the battery surface.

In the prior art, an inverted pyramid suede is formed on the surface of the silicon wafer through a texturing step. The suede is a single suede microstructure, and the anti-reflective effect of the pyramid suede is due to the bonding of the metal grid lines to the battery surface. There is often a contradiction between the forces. The smaller the surface texture, the better the anti-reflection effect. The larger the surface texture, the better the bonding force between the metal grid wire and the battery surface. This makes it difficult for the surface structure of the solar cell to take into account the anti-reflection effect and the metal grid. Line adhesion quality.

In order to overcome this problem, in the prior art, a preparation method for forming two different texture sizes has been proposed. This method usually requires the use of a mask to form a patterned structure on the surface of the substrate, thereby forming a hollow area and a mask on the surface of the substrate. area, perform texturing treatment on the surface of the base body corresponding to the hollow area to form a large-sized suede surface, then remove the covered area, and then perform texturing treatment on the part with the covered area removed, thereby forming a small-sized suede surface. However, this method requires mask production and requires mask removal and texturing twice, making the entire process complicated and the operation cost high.

Contents of the invention

Therefore, the purpose of this application is to provide a substrate processing method, especially a substrate texturing method, through which the entire texturing process can be simplified, and thereby reduce the operating cost of the entire substrate processing method. , and thereby reduce the overall cost of the solar cells obtained by this method.

According to one aspect of the present application, a substrate processing method is provided, which method includes providing a substrate, the substrate including a first surface; performing regionalized oxidation on the first surface of the substrate, thereby forming on the first surface a composition including: The first region of the oxide layer and the second region that does not include the oxide layer; the substrate is entered into an alkali solution for a predetermined period of time, such as 10s to 600s for texturing, thereby forming a third region on the first surface. A suede structure is provided and a second suede structure is formed on the second area of the first surface, and the size of the first suede structure is smaller than the size of the second suede structure.

In one embodiment, the substrate is a silicon substrate, especially an n-type silicon substrate.

In one embodiment, when the substrate is a silicon substrate, the oxide layer is a silicon oxide layer, and the regionalized oxidation of the n-type silicon substrate is preferably formed through a laser oxidation process. By adjusting the energy of the laser and the irradiation time, it can be easily Control the oxidation thickness of the oxide layer.

In one embodiment, the alkali solution is a KOH solution or a NaOH solution. After the substrate including the regionalized oxide layer is immersed in the alkali solution, first, the alkali solution textures the second area of the silicon oxide-free mask layer, and at the same time, the alkali solution Begin to corrode the silicon oxide mask layer in the first area. As the silicon oxide mask layer is removed by the alkali solution, the alkali solution begins to texturize the first area with the silicon oxide mask layer; use the alkali solution to interact with the silicon matrix and oxidize The different reaction rates of the layers make the second area have a long reaction time and obtain a large suede structure; while the first area has a short reaction time and obtain a small suede structure. Thus, through a simple step, different sizes of suede are obtained. surface structure.

In one embodiment, the first region may be a region on which a metal gate line will not be formed, and the second region may be a region on which a metal gate line will be formed. Accordingly, in this specification and in the claims , the first region is also called the non-metal gate line region, and the second region is also called the metal gate line region.

Therefore, by forming a large-sized textured structure in the metal grid area, the adhesion between the metal grid and the substrate can be improved, and by controlling the power of the laser, the irradiation time of the laser, and the scanning path of the laser, the oxidation can be accurately controlled. The thickness of the layer and the size difference between the metal grid area and the non-metal grid area are well controlled, thereby achieving an organic balance between the grid adhesion and the anti-reflection effect on the cell surface, making this method very good. Process controllability.

In one embodiment, the substrate further includes a second surface opposite the first surface, and the method further includes performing regionalized oxidation on the second surface to form a third region with an oxide layer and a third region without an oxide layer. the fourth area. Therefore, when the substrate having both the first surface and the second surface subjected to regionalized oxidation is immersed in an alkali solution, the first surface and the second surface of the substrate can be textured at the same time, and the first surface and the second surface can be textured at the same time. Suede structures of different sizes are formed simultaneously on the two surfaces.

Furthermore, by controlling the power, irradiation time, scanning path, etc. of the laser in the regionalized oxidation step of the first surface and the second surface, the thickness and thickness of the oxide layer formed on the first surface and the second surface can be customized. Size, position, etc., thus, suede structures of different sizes and layouts can be formed on the first surface and the second surface of the base body as needed.

According to the method of the present application, masking and multiple texturing steps are omitted, thereby simplifying the texturing process of the entire substrate, thereby reducing production costs. By forming textured structures of different sizes in different areas of the substrate surface, the grid lines of the solar cells produced by the method of the present invention have good adhesion to the cell surface, and at the same time, the non-grid line areas have better anti-reflection effects, making the solar cells The battery can achieve the best anti-reflection effect while also greatly improving the bonding performance of the battery grid on the battery surface.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings of the embodiments of the present invention will be briefly introduced below. The drawings are only used to illustrate some embodiments of the present invention, but not to limit all embodiments of the present invention thereto.

1A to 1G are schematic diagrams illustrating each step of a substrate processing method according to the first embodiment of the present application;

2A to 2C are schematic diagrams showing steps of a texturing process according to a second embodiment of the present application; and

3A to 3C are schematic diagrams showing steps of a texturing process according to a third embodiment of the present application.

Detailed ways

Below, the technical solution of the present disclosure is described in detail with specific embodiments of the present disclosure. It is to be noted that in the following description and in the claims, reference to specific numerical values is not intended to be exact but encompasses reasonable deviations.

The present disclosure provides a silicon wafer processing method, in particular, a silicon wafer processing method for solar cells. The method includes performing regionalized oxidation on the surface of a substrate, especially an n-type silicon substrate, whereby the third layer on the surface is An oxide layer mask is formed on one area, especially a silicon oxide mask, and there is no oxide layer mask on the second area, and then the substrate on which the oxide layer mask is selectively formed is immersed in an alkali solution, so that the alkali solution is first mixed with The second area without the oxide mask reacts to texturize the area. At the same time, the alkali solution reacts with the oxide mask to gradually remove the oxide mask. After the oxide mask is removed, the alkali solution continues to react with the oxide mask. The silicon material of the base reacts to texturize the first area. Therefore, due to the different time between the first area and the second area of the base surface being in direct contact with the alkali solution, a textured structure is formed in the first area and the second area. have different sizes, that is, since the second area without the oxide mask reacts with the alkali solution first, while the first area with the silicon oxide mask does not react with the alkali solution until the silicon oxide mask is removed by the alkali solution , therefore, the size of the suede structure in the second area is larger, while the size of the suede structure in the first area is smaller. Preferably, the second area corresponds to the area of the silicon substrate where the metal grid line is to be formed, or is called the metal grid line area. Therefore, in subsequent steps, due to the larger size of the texture structure in the second area, the The attachment of the metal grid lines to the substrate, and the textured structure in the first area is smaller in size. This area has a better anti-reflection effect, so that the obtained solar cell can achieve the best anti-reflection effect while being greatly improved. The bonding performance of battery grid wires on the battery surface.

As an embodiment of the present application, the above-mentioned regionalized oxidation step is preferably achieved by irradiating a region of the substrate surface with a laser, for example, by driving the laser to irradiate the substrate surface along a predetermined path, thereby oxidizing the substrate on the first region, and on the second region. A silicon oxide mask with a predetermined thickness is obtained on the surface of a region of the substrate. The thickness can be, for example, in the range of 0.5 to 10 nm. By controlling the power of the laser, the irradiation time, etc., the thickness of the formed silicon oxide mask can be controlled, and thereby The size of the pile structure on the first and second regions can be controlled.

In one embodiment of the present application, the above-mentioned alkali solution can be a KOH solution or a NaOH solution. By controlling the time when the substrate is immersed in the alkali solution, the size of the textured structure formed can be controlled.

Although the formation of the texture structure on one surface of the substrate is described above, the texture structure may also be formed on both opposing surfaces of the substrate, for example, after regional oxidation of the first surface or simultaneously with regional oxidation of the second surface. , thus, an area including the oxide layer mask and an area not including the oxide layer mask are formed on both the first surface and the second surface of the substrate, so that when the substrate is immersed in the alkaline solution, the two surfaces are simultaneously The above-mentioned texturing process improves the texturing efficiency, simplifies the process, and reduces the cost. In addition, by controlling the laser power, irradiation time, etc. when the two surfaces are oxidized, the thickness of the silicon oxide mask formed on the first surface and the second surface can be controlled, thereby obtaining different sizes on the first surface and the second surface. Suede construction.

The above-mentioned texturing process can be used as a part of the solar cell silicon wafer processing. Therefore, after forming a textured structure on the first surface and/or the second surface of the substrate, the texture-containing material can be deposited on the first and/or second surface respectively. A silicon film is deposited, and then a transparent conductive film is deposited, and then a first surface contact electrode and/or a second surface metal contact electrode is produced.

As mentioned above, by forming a textured structure with a large size in the metal grid area, the contact electrode produced can have better adhesion.

Although in the above description, the solar cell silicon wafer includes an n-type silicon substrate, the present application is not limited thereto. Other types of silicon substrates may be used, such as p-type silicon substrates. The present application is not limited to a specific silicon substrate. type.

Embodiments according to the present application will be described in detail below with reference to the accompanying drawings, wherein FIGS. 1A to 1G are schematic diagrams showing steps according to the first embodiment of the present application, and FIGS. 2A to 2C are schematic diagrams according to the second embodiment of the present application. 3A to 3C are schematic diagrams showing various steps of the texturing process according to the third embodiment of the present application.

First embodiment:

As shown in Figures 1A to 1G, the first embodiment is a solar cell silicon wafer processing method. The processing method includes the following steps:

As shown in FIG. 1A , in step A, an n-type silicon substrate 1 is provided into a processing chamber (not shown). The silicon substrate 1 has a first surface 11 and a second surface 12 . The first surface of the silicon substrate 1 has The second surface 12 of the silicon substrate 1 has a metal gate line region 11a and a non-metal gate line region 11b. The second surface 12 of the silicon substrate 1 has a metal gate line region 12a and a non-metal gate line region 12b. It is noted that the metal gate line region refers to a region in which a metal gate line will be formed in a subsequent step, and the non-metal gate line region refers to a region in which a metal gate line is not formed in a subsequent step.

As shown in FIG. 1B , in step B: a silicon oxide mask layer 2 with a thickness of 0.5 nm to 10 nm is formed by laser oxidation on the non-metal gate line area 11 b of the first surface 11 of the n-type silicon substrate 1 ; wherein, laser oxidation The process conditions include, for example, selecting an ultraviolet picosecond laser with a wavelength of 355 nanometers and setting the energy density to 0.02-1.50 J/cm ² , thereby forming a regionalized silicon oxide mask layer on the first surface.

As shown in Figure 1C, in step C, surface texturing is performed. In this step C, the silicon substrate with the silicon oxide mask layer 2 partially formed on the surface is immersed in an alkali solution for a predetermined period of time to react. The alkali solution is, for example, 0.1 %~10% volume concentration KOH solution or NaOH solution KOH solution or NaOH solution. During the reaction process, the alkali solution first textures the area of the silicon oxide mask layer 2, that is, the metal gate line area. At the same time, the alkali solution begins to corrode the silicon oxide mask layer 2. As the silicon oxide mask layer 2 is eroded by the alkali solution, removal, the alkali liquid begins to texturize the area with the silicon oxide mask layer 2, that is, the non-metal gate line area; using the characteristics of the different reaction rates of the alkali liquid with the silicon matrix and silicon oxide (SiOx), the metal gate lines The reaction time of the region 11a is long, and a large texture structure is obtained; the reaction time of the non-metal grid line region 11b is short, and a small texture structure is obtained.

Through the above steps, a substrate with different suede structures on the surface is obtained. Subsequently, the above-mentioned silicon wafer is made into a solar cell silicon wafer through the steps shown in FIGS. 1D to 1G, for example.

As shown in FIG. 1D, in step D, a first layer of silicon-containing film 3 on the first surface and a first layer of silicon-containing film 3 on the second surface are respectively deposited on the first surface 11 and the second surface 12 of the n-type silicon substrate 1 including a textured structure. A layer of silicon-containing film 4; wherein, the first layer of silicon-containing film 3 on the first surface and the first layer of silicon-containing film 4 on the second surface are, for example, intrinsic silicon-containing films, which can be, for example, microcrystalline, nanometer, or amorphous silicon. , silicon oxide or silicon carbide and other thin film layers, a single layer with the same performance or a multi-layer or a stack of several silicon-containing films with different properties, with a thickness of 1 to 50 nm.

As shown in Figure 1E, in step E, a second layer of silicon-containing film 5 on the first surface and a second layer of silicon-containing film 6 on the second surface are respectively deposited on the first surface 11 and the second surface 12 of the n-type silicon substrate 1 ; Wherein, the second layer of silicon-containing film 5 on the first surface and the second layer of silicon-containing film 6 on the second surface are, for example, doped silicon-containing films, which can be microcrystalline, nanometer, amorphous silicon, silicon oxide or silicon carbide. Among the thin film layers, a single layer with the same performance or a multi-layer or several laminated silicon-containing films with different properties, the thickness of which is preferably 1 to 50 nm; the first surface, the second layer of the silicon-containing film and The doping categories of the second silicon-containing film on the second surface are respectively n-type and p-type or p-type and n-type.

As shown in Figure 1F, in step F, a first surface transparent conductive film 7 and a second surface transparent conductive film 8 are respectively deposited on the first surface 11 and the second surface 12 of the n-type silicon substrate 1, where the first surface The transparent conductive film 7 and the second transparent conductive film 8 are a stack or mixture of one or more doped metal oxides or nitrides. The metal oxide can be selected from indium oxide, tin oxide, zinc oxide, and cadmium oxide, for example. , titanium nitride, the metal nitride can be titanium nitride, for example, and its doping element can be selected from indium, tin, calcium, aluminum, cadmium, zinc, cerium, fluorine, for example, and its thickness is preferably 1 to 100nm;

Then, as shown in FIG. 1G , in step G, the first metal gate line region 11 a (second region) on the first surface 11 and the metal gate line region 12 a on the second surface 12 of the n-type silicon substrate 1 are respectively formed. The surface metal contact electrode 9 and the second surface metal contact electrode 10 are then subjected to light injection annealing treatment to obtain the heterojunction solar cell of the present invention.

Among them, the front metal contact electrode 9 and the back metal contact electrode 10 can be formed by screen printing, electroplating or a combination of the two.

Although in the first embodiment, regionally different suede structures are formed only on the first surface 11 of the base 1 , the present application is not limited thereto, and can be formed on the first surface 11 and the second surface 12 Regionally different suede structures are formed on both surfaces at the same time. Although in the above description, the method of the present application is described by taking the formation of heterojunction solar cells as an example, the present application is not limited thereto, but can be combined with any solar cell manufacturing method that requires texturing, thereby obtaining Desired suede structure.

Second embodiment

The following describes a wafer processing method according to the second embodiment of the present application with reference to FIGS. 2A to 2C . It should be understood that in the following description, the texturing process is mainly focused on, and the process after texturing can refer to FIGS. 1D to 2C . The description of Figure 1G will not be repeated here.

As shown in Figure 2A, in step A, an n-type silicon substrate 1 is provided. The silicon substrate 1 is provided with a first surface 11 and a second surface 12. The first surface of the silicon substrate 11 has a metal gate line region 11a and a non-metal gate line. In the region 11b, the first surface of the silicon substrate 12 has a metal gate line region 12a and a non-metal gate line region 12b.

Before performing regionalized oxidation on the silicon substrate, optionally, the silicon substrate may be processed, that is, in step A0, the silicon substrate 1 is subjected to double-sided polishing and gettering treatment.

Then, as shown in FIG. 2B, in step B, a regionalized oxidation step is performed. In this step, the first surface 11 of the n-type silicon substrate 1 has a non-metal gate line region 11b and a second surface of the n-type silicon substrate 1. The surface 12 has the non-metallic grid area 12b, and the silicon oxide mask layer 2 with the same thickness ranging from 0.5nm to 10nm is formed through laser oxidation. Among them, the laser oxidation process can use an ultraviolet picosecond laser with a wavelength of 355 nanometers and an energy density of 0.02～1.50J/cm ² .

Subsequently, in step C, surface texturing is performed. In the surface texturing step, the silicon substrate with the silicon oxide mask layer 2 formed on the surface is immersed in an alkali solution for reaction. The alkali solution is a KOH solution or a NaOH solution. During the reaction process, the alkali solution affects the area of the silicon oxide mask layer 2. Texturing is carried out, and at the same time, the alkali solution begins to corrode the silicon oxide mask layer 2. As the silicon oxide mask layer 2 is removed by the alkali solution, the alkali solution begins to texturize the area with the silicon oxide mask layer 2; using the alkali solution and The different reaction rates between the silicon matrix and silicon oxide (SiOx) make the reaction time of the metal grid area 11a on the first surface and the metal grid area 12a on the second surface long, resulting in a large textured structure; the non-metallic area on the first surface The reaction time of the gate line area 11b and the second surface non-metal gate line area 12b is short, resulting in a small texture structure, as shown in Figure 2C.

The subsequent process is the same as described with reference to FIGS. 1D to 1G and therefore will not be described again, whereby a solar cell silicon wafer with good adhesion is obtained.

Third embodiment

According to the second embodiment, the thickness of the silicon oxide layer mask formed on the first surface and the second surface may be the same or different, thereby forming different thicknesses on the metal gate line areas of the first surface and the second surface. sized pile structure as described in the third embodiment. The texturing process according to the third embodiment will be described below with reference to FIGS. 3A to 3C.

First, as shown in FIG. 3A, in step A, an n-type silicon substrate 1 is provided, which has a first surface 11 and a second surface 12. The first surface 11 of the silicon substrate has a metal gate line region 11a and a non-metal gate. In the line region 11b, the second surface 12 of the silicon substrate has a metal gate line region 12a and a non-metal gate line region 12b.

Before performing regionalized oxidation, step A0 is optionally performed, in which the silicon substrate 1 is subjected to double-sided polishing and gettering treatment.

Then, as shown in FIG. 3B , a regionalized oxidation step is performed. In this step, the non-metallic gate line region 11b of the first surface 11 of the n-type silicon substrate 1 and the non-metallic gate line region 11b of the second surface 12 of the n-type silicon substrate 1 are The metal gate line areas 12b are respectively formed with silicon oxide mask layers 2 with different thicknesses ranging from 0.5 nm to 10 nm through laser oxidation. For example, the silicon oxide mask layer 2 on the second surface is thicker than the silicon oxide mask layer 2 on the first surface. thickness; this can be achieved, for example, by controlling the power, irradiation time, etc. of the laser that irradiates the first surface and the second surface during the laser oxidation process. Among them, for example, an ultraviolet picosecond laser with a wavelength of 355 nanometers and an energy density of 0.02 to 1.50 J/cm ² is used.

As shown in Figure 3C, surface texturing step C is performed. In this step, the silicon substrate with the silicon oxide mask layer 2 formed on the surface is immersed in an alkali solution for reaction. The alkali solution is a KOH solution or a NaOH solution. During the reaction The alkali solution textures the area without silicon oxide mask layer 2, and at the same time, the alkali solution begins to corrode the silicon oxide mask layer 2. As the silicon oxide mask layer 2 is removed by the alkali solution, the alkali solution begins to corrode the silicon oxide mask layer 2. The area of layer 2 is textured; the characteristics of the different reaction rates between the alkali solution and the silicon matrix and silicon oxide (SiOx) are used to make the reaction time of the metal grid line area 11a on the first surface and the metal grid line area 12a on the second surface the longest. , a large suede structure is obtained; the non-metallic grid line area 11b on the first surface is the second, and a small suede structure is obtained; the reaction time of the non-metallic grid line area 12b on the second surface is the shortest, and a micro suede structure is obtained, as shown in Figure 3C Show.

Thus, by controlling the power of the laser, the irradiation time, etc., the thickness of the oxide layer mask is controlled, thereby controlling the size of the final textured structure.

As described in the first embodiment, after the above texturing process is completed, the silicon wafer with the textured structure is further processed, thereby obtaining a solar cell. These steps are basically the same as those described with reference to FIGS. 1D to 1G in the first embodiment. Therefore, the same content can be applied to the third embodiment and will not be described again.

The present application has been described in detail through three embodiments above, but those skilled in the art can understand that the present application is not limited thereto, but may include any modifications or variations. For example, although in the above embodiments, in The laser oxidation process is used in the regionalized oxidation step, but the application is not limited to this. Other oxidation processes or deposition processes may be used to form a regionalized oxide layer mask on the surface of the substrate. In addition, after forming the textured structure, by appropriately selecting the subsequent processes, the substrate with the regionalized textured structure of the present application can be further made into a heterojunction solar cell. However, the application is not limited to this, but the substrate can be It is used to further manufacture other types of solar cells, such as PERC type solar cells, but the application is not limited thereto. In the above description and claims, various steps are described in order, but it should be understood that this does not mean that these steps must be performed in the order described, but that some steps can be performed simultaneously or in reverse order. This application Not limited to a specific sequence of steps.

Therefore, according to this application, the following items are included but not limited to:

Item 1. A wafer processing method, including:

providing a substrate including a first surface;

Regionalized oxidation step: In this step, the first surface is regionally oxidized to form a first region including an oxide layer and a second region not including an oxide layer; and

Texturing step: immersing the regionalized and oxidized substrate in an alkali solution for a predetermined time to form a first texture structure on the first area and a second texture structure on the second area, the third The dimensions of the first pile structure are smaller than the dimensions of the second pile structure.

Item 2. The method according to item 1, wherein the substrate is a silicon substrate, especially an n-type silicon substrate.

Item 3. The method of item 1 or 2, wherein the regionalized oxidation step includes irradiating the first area of the first surface along a predetermined path with a laser.

Item 4. The method as described in item 3, wherein the laser uses an ultraviolet picosecond laser with a wavelength of 355 nanometers, and the energy density is set to 0.02-1.50J/cm ² .

Item 5. The method according to any one of Items 1 to 4, wherein the thickness of the oxide layer is in the range of 0.5 nm to 10 nm.

Item 6. The method according to any one of items 1 to 5, wherein the substrate further includes a second surface opposite to the first surface, and before the texturing step, the method further includes: regionalized oxidation the second surface to form a third region including an oxide layer and a fourth region not including an oxide layer.

Item 7. The method of item 6, wherein the thickness of the oxide layer formed on the first region is different from the thickness of the oxide layer formed on the third region.

Item 8. The method according to any one of items 1 to 7, wherein the alkali solution is a KOH or NaOH solution.

Project 9. A method for preparing silicon wafers for solar cells, including:

Provide a substrate prepared using the method of any one of items 1 to 8; and

A metal contact electrode is formed on the second area.

Project 10. A method for preparing silicon wafers for solar cells, including:

Providing a substrate prepared using the method described in item 6 or 7; and

Metal contact electrodes are formed on the second region and the fourth region respectively.

Item 11. The method of item 9 or 10, before forming the metal contact electrode, further comprising:

forming one or more silicon-containing films on the first surface and the second surface of the substrate; and

A transparent conductive film is formed on the silicon-containing film.

Item 12. The method of any of items 9 to 11, further comprising:

After forming the metal contact electrode, a light injection annealing process is performed.

Item 13. A silicon substrate, wherein the silicon substrate is obtained by the method according to any one of items 1 to 8.

Item 14. A solar cell silicon wafer, wherein the solar cell silicon wafer is obtained by using the method described in any one of items 9 to 12.

From the foregoing description, it will be apparent to those of ordinary skill in the art that, although the methods and devices described herein constitute exemplary embodiments of the present disclosure, the present invention is not limited to these specific embodiments, and Changes may be made to such embodiments without departing from the scope of the invention as defined by the claims. Additionally, it is to be understood that the present invention is defined by the claims and that it is not intended that any limitations or elements describing the exemplary embodiments set forth herein will be incorporated into the interpretation of any claim element unless such a limitation is expressly stated. or component. Likewise, it is to be understood that all noted advantages or objects of the invention disclosed herein need not be satisfied in order to fall within the scope of any claim, since the invention is defined by the claims and because even though this may not have been expressly stated herein There may also be inherent and/or unforeseen advantages of the claimed invention.

Claims (10)

1. A wafer processing method, comprising:

providing a substrate comprising a first surface;

a regional oxidation step: in this step, the first surface is regionally oxidized to form a first region including an oxide layer and a second region not including an oxide layer; and

and (3) wool making: immersing the regionally oxidized substrate in an alkaline solution for a predetermined time to form a first pile structure on the first region and a second pile structure on the second region, the first pile structure having a size smaller than a size of the second pile structure.

2. The method according to claim 1, wherein the substrate is a silicon substrate, in particular an n-type silicon substrate.

3. The method of claim 1 or 2, wherein the step of regionalizing oxidation comprises illuminating a first region of the first surface along a predetermined path with a laser.

4. A method according to claim 3, wherein the laser is a uv sheath second laser having a wavelength of 355 nm and an energy density of 0.02 to 1.50J/cm ² 。

5. The method of any one of claims 1 to 4, wherein the substrate further comprises a second surface opposite the first surface, the method further comprising, prior to the step of texturing: the second surface is regionally oxidized to form a third region including the oxide layer and a fourth region not including the oxide layer.

6. The method of claim 5, wherein a thickness of the oxide layer formed on the first region is different from a thickness of the oxide layer formed on the third region.

7. A preparation method of a solar cell silicon wafer comprises the following steps:

providing a substrate prepared by the method of any one of claims 1 to 6; and

and forming a metal contact electrode on the second region.

8. A preparation method of a solar cell silicon wafer comprises the following steps:

providing a substrate prepared by the method of claim 4 or 5; and

and forming metal contact electrodes on the second region and the fourth region respectively.

9. A silicon substrate, wherein the silicon substrate is obtained by the method of any one of claims 1 to 6.

10. A solar cell silicon wafer, wherein the solar cell silicon wafer is obtained using the method of claim 7 or 8.