CN111192934B - Preparation method of silicon oxide etching template for silicon substrate, silicon substrate and application - Google Patents
Preparation method of silicon oxide etching template for silicon substrate, silicon substrate and application Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/362—Laser etching
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention provides a preparation method of a silicon oxide etching template for a silicon substrate, which comprises the following steps: selecting a preset pattern, wherein the preset pattern is composed of a pixel matrix, the pixel matrix is composed of a plurality of pixel points, and each pixel point corresponds to a gray value; converting the gray value corresponding to each pixel point into the size of a unit area on the silicon oxide layer corresponding to the position of the pixel point; outputting a vector graph according to the sizes of all the unit areas, wherein the vector graph comprises the shapes and the sizes of all the unit areas corresponding to each pixel point of the preset pattern; inputting the vector pattern into a laser marking machine, guiding the laser beam direction of the laser marking machine by using the vector pattern, ablating from the silicon oxide layer to the silicon layer direction, forming a plurality of notches corresponding to the vector pattern in a plurality of unit areas on the silicon oxide layer, and obtaining the silicon oxide etching template. The invention can draw any gray image on the silicon solar cell panel on the premise of not losing obvious photoelectric conversion performance.
Description
Technical Field
The invention relates to the field of semiconductor devices, in particular to a preparation method of a silicon oxide etching template for a silicon substrate, the silicon substrate and application.
Background
With the increasing popularity of distributed photovoltaic energy, solar cells are gradually beginning to be applied on a large scale in the construction of towns, such as laying solar panels on roofs or roads to form part of a town energy system. In addition, the solar energy power supply can be integrated on some low-power-consumption portable electronic devices, such as solar-driven watches, calculators and the like.
Since the cost of solar power generation is also higher than that of conventional energy sources, research on solar cells is still focused on improving the efficiency of light-electricity conversion of solar cells and reducing the cost of the cells. In order to absorb more available light as much as possible, the conventional silicon-based solar cell is designed to be black or dark blue by preparing a textured or antireflection layer to reduce the reflectivity so as to improve the photoelectric conversion efficiency, which results in a relatively single appearance of the silicon-based solar cell. In addition, to meet the requirement of transporting photogenerated carriers, metal grid lines are often applied to the preparation of top electrodes of silicon solar cells. These electrodes are visible to the naked eye and their presence can also disrupt the uniformity of the appearance of the solar cell.
However, in these distributed photovoltaic application scenarios, people are required to frequently interact with the solar cell panels. Accordingly, the design of the appearance of solar panels may become increasingly important in the future when distributed photovoltaic systems are prevalent.
In order to express the artistry of the solar cell panel, it is desirable to draw a pattern thereon. The prior art has realized the depiction of the pattern by covering the solar cell with a patterned semi-transparent filter film, however, in this way the filter film itself absorbs and reflects a large amount of visible light, which results in a significant drop in the photo-electric conversion efficiency of the solar cell. Painting the solar cell to achieve the image also blocks the incidence of light, resulting in a significant decrease in the photoelectric conversion efficiency of the solar cell.
Disclosure of Invention
An object of the present invention is to express the artistry of solar cell panels.
It is a further object of the present invention to trace a pattern on a cell panel without a significant drop in the cell's light-to-electricity conversion efficiency.
Particularly, the invention provides a preparation method of a silicon oxide etching template for a silicon substrate, wherein the surface of the silicon substrate is provided with a silicon layer and a silicon oxide layer, and the preparation method comprises the following steps:
selecting a preset pattern, wherein the preset pattern is composed of a pixel matrix, the pixel matrix is composed of a plurality of pixel points, and each pixel point corresponds to a gray value;
converting the gray value corresponding to each pixel point into the size of a unit region on the silicon oxide layer corresponding to the pixel point position;
outputting a vector graph according to the sizes of all the unit areas, wherein the vector graph comprises the shapes and the sizes of all the unit areas corresponding to each pixel point of the preset pattern;
inputting the vector graph into a laser marking machine, guiding the laser beam direction of the laser marking machine by using the vector graph, and ablating from the silicon oxide layer to the silicon layer direction to form a plurality of notches corresponding to the vector graph in a plurality of unit areas on the silicon oxide layer, thereby preparing and obtaining the silicon oxide etching template.
Optionally, before converting the gray scale value corresponding to each pixel point into the size of the unit region on the silicon oxide layer corresponding to the pixel point position, the method further includes the following steps:
opening the preset pattern by using programming software, and reading a gray matrix corresponding to the preset pattern, wherein the gray matrix comprises a gray value corresponding to each pixel point;
outputting a vector graphic according to the sizes of all the unit areas comprises the following steps:
outputting a vector graphic file containing the sizes of all unit areas on the silicon oxide layer;
and drawing the corresponding vector graphics in the vector graphics file in a plane drawing software according to the vector graphics file.
Optionally, the method further comprises the following steps between outputting a vector pattern according to the sizes of all the unit areas and inputting the vector pattern into a laser marking machine:
parameters of the laser marking machine are adjusted so that the laser beam ablates only the silicon oxide layer in a subsequent step of ablation.
Optionally, the parameters of the laser marking machine at least include frequency, scanning speed, scanning frequency and Z-axis height of the laser marking machine;
the frequency range of the laser marking machine is 50-65kHz, the scanning speed range of the laser marking machine is 135-150mm/s, the scanning frequency range of the laser marking machine is 1-3 times, and the Z-axis height range of the laser marking machine is 40-60 mm.
Optionally, the shape of the unit area is selected to be square or circular.
In particular, the present invention also provides a method of patterning a silicon substrate, comprising the steps of:
preparing a silicon oxide etching template by the preparation method;
and etching the silicon substrate at the plurality of notches by using the silicon oxide etching template through a wet etching method so as to form patterns which are visually consistent with the preset patterns on the silicon substrate.
Optionally, in the wet etching method, the etching solution is an alkaline solution, and the solute is an alkaline solute.
In particular, the present invention also provides a silicon substrate having a first surface and a second surface opposite to the first surface, the silicon substrate comprising:
a plurality of silicon microstructures having different reflectivities, each of the silicon microstructures comprising a plurality of silicon microcells having the same reflectivity, each of the silicon microcells being configured on the silicon substrate and etched to a predetermined depth from the first surface of the silicon substrate toward a direction close to the second surface; wherein
The number of each silicon microstructure and the arrangement mode of all the silicon micro units on the silicon substrate are determined according to a preset pattern, so that the pattern formed by all the silicon micro units is visually consistent with the preset pattern.
Optionally, each of the plurality of silicon microstructures is the same shape; and is
The silicon microstructures of the same kind have the same size of each silicon microcell, and the silicon microstructures of different kinds have different sizes of each silicon microcell.
In particular, the invention also provides an application of the silicon substrate, and the silicon substrate is applied to a solar cell.
In the prior art, monocrystalline silicon/polycrystalline silicon solar cells are monotonous blue, purple or black panels, and the current technology cannot realize the construction of complex patterns on the solar cells. By using the scheme of the invention, any gray image can be drawn on the silicon solar cell panel on the premise of not losing obvious photo-electric conversion performance. This wearable power supply unit in future has important effect like fields such as intelligent wrist-watch, intelligent bracelet and solar energy knapsack, photovoltaic building integration like photovoltaic roof, photovoltaic wall and photovoltaic road etc. photovoltaic art.
In addition, the silicon substrate with the patterned surface is applied to the solar cell, so that the solar cell adds artistic value to the original functional value, which is beneficial to expanding the application range of the solar cell and possibly promoting the popularization of a distributed photovoltaic system.
The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.
Drawings
Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:
FIG. 1 is a schematic flow chart diagram of a method of making a silicon oxide etching template for a silicon substrate according to one embodiment of the present invention;
FIG. 2 is a scanning electron micrograph of silicon microcells of the same size periodically arranged and etched on a silicon substrate, according to one embodiment of the present invention;
FIG. 3 is a reflection spectrum of a silicon substrate having silicon microcells with top edges of 5 μm, 15 μm, 20 μm, 25 μm, 30 μm, 32 μm, 34 μm, and 35 μm in accordance with one embodiment of the present invention;
FIG. 4 is a scatter plot of the reflectivity versus area of the top square of the inverted pyramid structure shown in FIG. 3;
fig. 5 is a corresponding graph of the size of corresponding silicon microcells at different gray scale values of Gamma 1.8 according to one embodiment of the present invention;
FIG. 6 is a schematic view of the shape of an opening in a photolithographic reticle according to one embodiment of the invention;
FIG. 7 is a partial scanning electron microscope view of a silicon oxide etching template according to one embodiment of the invention;
FIG. 8 is a schematic flow chart diagram of a method of patterning a silicon substrate in accordance with one embodiment of the present invention;
FIG. 9 is a partial scanning electron microscope view of a silicon substrate having a patterned surface in accordance with one embodiment of the invention;
FIG. 10 is a scanning electron microscope image with a silicon microcell according to one embodiment of the present invention;
FIG. 11 is a schematic view of a selected default pattern according to one embodiment of the present invention;
FIG. 12 is a schematic block diagram of a silicon substrate having a patterned surface in accordance with one embodiment of the present invention;
fig. 13 is a schematic diagram of applying a silicon solar cell to a dial of a smart watch according to one embodiment of the present invention.
Detailed Description
Fig. 1 shows a schematic flow diagram of a method of preparing a silicon oxide etching template for a silicon substrate having a silicon layer and a silicon oxide layer on a surface thereof according to an embodiment of the present invention. As shown in fig. 1, the preparation method comprises:
step S100, selecting a preset pattern, wherein the preset pattern is composed of a pixel matrix, the pixel matrix comprises a plurality of pixel points, and each pixel point corresponds to a gray value;
step S200, converting the gray value corresponding to each pixel point into the size of a unit area on the silicon oxide layer corresponding to the position of the pixel point;
step S300, outputting a vector graph according to the sizes of all the unit areas, wherein the vector graph comprises the shapes and the sizes of all the unit areas corresponding to each pixel point of the preset pattern;
and S400, inputting the vector graph into a laser marking machine, guiding the laser beam direction of the laser marking machine by using the vector graph, ablating the silicon layer from the silicon oxide layer to form a plurality of notches corresponding to the vector graph in a plurality of unit areas on the silicon oxide layer, and thus preparing and obtaining the silicon oxide etching template.
In step S100, the preset pattern is a gray scale image. For example, the selected preset pattern is a 4-bit gray picture in a computer selected at will, and the 4-bit gray picture includes 16 gray values, that is, pixel points included in the preset pattern have 16 middle gray values. This means that the opening size of the region to be etched on the mask blank substrate is 16 kinds. In this embodiment, a 4-bit gray image is used, but the invention is not limited thereto, and a gray image with more gray values, such as an 8-bit gray image, may also be used.
Before step S200, in order to construct the correspondence between the unit area size on the silicon oxide layer and the 4bit gray scale value of the picture, it is necessary to determine the unit area size and the reflectivity size of the silicon microcells with different sizes finally obtained under the arrangement of the unit areas, wherein the size of the top edge of the silicon microcell is equal to the size of the notch in step S400. In one embodiment, the silicon microcell is in the shape of an inverted pyramid. The unit area was set to be a square with a side of 40 μm, and the inverted pyramid-shaped silicon microcell was centered in the unit area. In other embodiments, the side length of the unit region may be set to 5 to 1000 μm, the positive direction may be set to another shape such as a rectangle as needed, and the inverted pyramid-shaped silicon microcell may not necessarily be constructed at the center of the unit region, and may be at any position of the unit region.
First, it is necessary to prepare silicon microcells of certain sizes periodically arranged and etched on a bulk silicon substrate. FIG. 2 shows a scanning electron micrograph of a periodic arrangement of identically sized silicon microcells etched on a silicon substrate, according to one embodiment of the present invention. For example, silicon microcells having top edges of 5 μm, 15 μm, 20 μm, 25 μm, 30 μm, 32 μm, 34 μm and 35 μm, respectively, were prepared and tested for reflectivity of these structured silicon substrates, and the results of the reflection spectra are shown in FIG. 3.Then, the reflectivity of each sample at 550nm is taken, a scatter diagram of the square area at the top of the reflectivity-inverted pyramid structure is made, as can be seen from fig. 4, the reflectivity and the structure area show linear negative correlation, and the formula after linear fitting is that R is 36.65-0.01800a, wherein R is the reflectivity (%), and a is the square area size (μm)2). The size of the top edge of the inverted pyramid at any reflectivity value can be determined by this formula.
It will be appreciated that the above formula can only correspond to the case where 40 μm square is used as the unit area size, and that changing the unit area size requires re-measuring the reflectivity and redefining the fit. Even if the 40 μm square is used as the unit area size, the fitting equation in this example is varied depending on the variation of the measured value and the method of fitting calculation, but the effect of the finally presented pattern is not significantly affected by a slight variation.
Note that, in the computer, it is defined that the luminance values corresponding to different grays are needed to be Gamma-corrected (y ═ x)GammaX is a linear quantity, y is a nonlinear quantity after correction, and it can be understood that, considering that 16 gray values are equally divided, the brightness change of every two adjacent gray values is the same, and actually, the brightness of the light of the adjacent gray values exponentially rises according to the Gamma value), the essence of Gamma correction is that human eyes feel nonlinear to the linearly changed light intensity, and the definition of silicon microcells with different reflectivities on the silicon substrate corresponding to the preset pattern pixel points also needs to comply with the Gamma correction. The area A is 0-1444 μm, as can be seen from the formula based on R36.65-0.01800A (unit area size 40 μm)2In the range of (1444 corresponds to a square with a side length of 38 μm, and the maximum value is related to the processing precision of the mask plate and the selected unit area period of 40 μm), the value of the reflectivity value is between 10.66% and 36.65%, the range is divided by a rule that Gamma is 1.8, and the range is divided into 16 equal parts according to 16 brightness values. Under the assumption of Gamma 1.8, the corresponding reflectivities at 16 gray-scale values are defined, as shown in fig. 5. And the size of the top side of the corresponding silicon inverted pyramid is found according to the formula R-36.65-0.01800A, and the sideThe length corresponds to the side length of the square converted on the mask plate. As shown in table 1 below:
TABLE 1
The corresponding relation between the gray value in the computer graph and the silicon microcells on the silicon substrate is completed through the table. It should be understood that the value of Gamma is not limited to 1.8, and may be any value in the range of 1.0-3.0, and different Gamma values only have an effect on the contrast of the graph.
After the corresponding relationship is defined, any 4-bit gray level picture needs to be converted into a silicon oxide etching template for photoetching. In Matlab software, each pixel point of a 4-bit gray picture is converted into an integer of 0 to 15 (0 represents the darkest, and 15 represents the brightest) in a matrix form, that is, the gray value corresponding to each pixel. The gray picture is opened in Matlab software, the gray matrix of the gray picture is read, the matrix is defined as A, and the scr file can be identified by AutoCAD software and is written by the following program, wherein the program covers the corresponding relation between the gray value in the upper table and the square in the photoetching mask plate, and the program comprises the following steps:
the scr file generated by the program is imported into AutoCAD to generate a vector graphic file for preparing the silicon oxide etching template. It should be noted that the program can be implemented in many ways, and is not limited to this. Both Matlab and AutoCAD may be replaced with other programming software or planimetric drawing software. In addition, the final recess formed in the programming process is square, however, due to the particularity of the alkali etching of the monocrystalline silicon, the pattern can be circular as shown in fig. 6, and can even be any pattern with an area within the range of the circular and the square. A photoetching mask plate can be prepared through the vector graphic file.
In step S200, the gray scale value corresponding to each pixel point can be converted into the size of the unit region on the silicon oxide layer corresponding to the pixel point position by using table 1. The positions of the silicon oxide layer unit areas correspond to the positions of the pixel points one by one, and the number of the silicon oxide layer unit areas also corresponds to the number of the pixel points one by one.
In step S300, the scr document generated by the program is imported into AutoCAD to generate a vector graphics file, and the vector graphics file has a vector graphics corresponding to the preset graphics.
Before step S400, the method further includes:
the parameters of the laser marking machine are adjusted so that the laser beam can only ablate the silicon oxide layer and hardly ablate the silicon layer in the subsequent step S400 of ablation.
Wherein, each parameter of the laser marking machine at least comprises the frequency, the scanning speed, the scanning frequency and the Z-axis height of the laser marking machine. In one embodiment, a laser marking machine produced by a Tianhong laser may be used. The laser frequency may be set to, for example, 50kHz, 57kHz, 62kHz, or 625kHz, or may be any other value in the range of 50-65 kHz. The scanning speed may be set to 135mm/s, 138mm/s, 142mm/s, 145mm/s or 150mm/s, for example, or may be any other value within the range of 135-150 mm/s. The number of scanning times may be set to, for example, 1 time, 2 times, or 3 times, or may be any other number of times within a range of 1 to 3 times. The z-axis height of the laser may be set, for example, to 40mm, 50mm or 60mm, or any other value in the range of 40-60 mm. The above parameters are kept within the above ranges, otherwise the laser beam may ablate into the silicon layer in step S400.
FIG. 7 shows a partial scanning electron microscope view of a silicon oxide etch template according to one embodiment of the invention. As can be seen in fig. 7, the oxide layer is removed after the silicon substrate is ablated by the laser beam. The near-surface silicon has undulations but is not etched deeply.
Fig. 8 shows a schematic flow diagram of a method of patterning a silicon substrate according to one embodiment of the invention. As shown in fig. 8, the patterning method, in addition to steps S100 to S400, further includes:
and S500, etching the silicon substrate at the plurality of notches by using a silicon oxide etching template through a wet etching method to form a pattern which is visually consistent with a preset pattern on the silicon substrate.
Wherein the silicon substrate is, for example, a monocrystalline silicon wafer with (100) crystal plane polishing. Wherein, the thickness of the oxide layer of the monocrystalline silicon can be 50nm, 200nm, 300nm, 500nm, 700nm, 900nm or 1000nm, or any thickness value of 50-1000 nm. But also a silicon nitride layer or other thin film materials resistant to alkali corrosion.
In step S500, the unmasked portion is etched into an inverted pyramid shape under the anisotropic etching condition of the hot alkali solution. In this example, the etching solution was formed after etching in an alkali/alcohol mixed solution (potassium hydroxide 20g, ultrapure water 10mL, ethanol 90mL) at 65 ℃ for 3 to 4 hours. In other embodiments, the specific etching conditions are flexible and adjustable, and the etching solution only needs to be an alkaline solution, the solute can be sodium hydroxide, potassium hydroxide or tetramethylammonium hydroxide, the ethanol can be other alcohols, such as isopropanol, even the ethanol can not be added under certain conditions, and the temperature of the etching solution can be between 30 and 120 ℃.
And finally, washing the silicon oxide etched by the alkali solution by ultrapure water, and dissolving the silicon oxide layer on the surface by hydrofluoric acid to form the silicon substrate with the patterned surface. As shown in fig. 9 and 10, a perfect inverted pyramid structure is etched on the silicon substrate. FIG. 11 is a diagram illustrating a selected default pattern, according to an embodiment of the invention. Fig. 12 is a schematic structural view of a silicon substrate having a patterned surface according to one embodiment of the present invention. As can be seen from fig. 11 and 12, the present invention produces a pattern that visually conforms to the predetermined pattern.
In particular, the invention also provides a silicon substrate, as shown in fig. 9, the silicon substrate 1 is prepared by the above method. The silicon substrate 1 has a first surface 10 and a second surface opposite to the first surface 10. The silicon substrate 1 comprises a plurality of silicon microstructures with different reflectivity, each silicon microstructure comprises a plurality of silicon microcells 20 with the same reflectivity, and each silicon microcell 20 is configured on the silicon substrate 1 and etched to a predetermined depth from the first surface 10 to the direction close to the second surface of the silicon substrate 1. The number of each silicon microstructure and the arrangement of all the silicon microcells 20 on the silicon substrate 1 are determined according to a preset pattern, so that the pattern formed by all the silicon microcells 20 is visually consistent with the preset pattern.
In one embodiment, the silicon microcells 20 in the plurality of silicon microstructures are identical in shape. Also, the silicon microcells 20 in the same silicon microstructure are the same size, and the silicon microcells 20 in different silicon microstructures are different in size. In one embodiment, the silicon substrate is a monocrystalline silicon wafer polished by a (100) crystal plane, but is not limited thereto, and may be monocrystalline silicon or polycrystalline silicon of other crystal planes, for example.
The silicon substrate 1 has a plurality of silicon microcells 20 with different sizes on the surface thereof, and the plurality of silicon microcells 20 with different sizes jointly form a pattern which is visually identical or substantially identical to a preset pattern. Referring to fig. 9 and 10, in this embodiment, the silicon microcell 20 has an inverted pyramid shape. Of course, the shape of the silicon microcell 20 is not limited thereto, and may be, for example, a square shape, a regular pyramid shape, or the like.
In the prior art, monocrystalline silicon/polycrystalline silicon solar cells are monotonous blue, purple or black panels, and the current technology cannot realize the construction of complex patterns on the solar cells. By using the scheme of the invention, any gray image can be drawn on the silicon solar cell panel on the premise of not losing obvious photo-electric conversion performance. This wearable power supply unit in future has important effect like fields such as intelligent wrist-watch, intelligent bracelet and solar energy knapsack, photovoltaic building integration like photovoltaic roof, photovoltaic wall and photovoltaic road etc. photovoltaic art.
In addition, the patterned silicon oxide etching template can be prepared by only one-step laser scanning ablation by utilizing the laser beam ablation method, the process is simple, the method is very suitable for large-scale production, and the ablation precision meets the requirement of displaying the silicon surface pattern. In addition, the silicon substrate with the patterned surface is applied to the solar cell, so that the solar cell adds artistic value to the original functional value, which is beneficial to expanding the application range of the solar cell and possibly promoting the popularization of a distributed photovoltaic system.
The silicon substrate can be applied to a solar cell as a silicon solar cell, for example, to a graphene/silicon heterojunction cell device, and is also applicable to a traditional silicon solar cell, especially a back junction back contact cell with a front surface without electrode contact. More importantly, besides generating electricity in a large area, the patterned silicon solar cell can also be applied to small wearable devices, for example, as shown in fig. 13, the patterned silicon solar cell can be used as a dial plate of a smart watch to continuously charge a battery in the watch and drive a low-power-consumption quartz movement, a global positioning system chip, various sensor chips or a bluetooth transmission chip. Such a non-display smart watch may not require charging or battery replacement at all, with the energy being continuously provided by a high efficiency, aesthetically pleasing patterned monocrystalline silicon battery. In addition to this, patterned solar cells will likely have greater potential applications in such areas where personalization, low power consumption, freedom from charging, and no longer particularly sensitive to the cost of solar cell power generation are needed.
Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.
Claims (10)
1. A preparation method of a silicon oxide etching template for a silicon substrate is characterized in that the surface of the silicon substrate is provided with a silicon layer and a silicon oxide layer, and the preparation method comprises the following steps:
selecting a preset pattern, wherein the preset pattern is composed of a pixel matrix, the pixel matrix is composed of a plurality of pixel points, and each pixel point corresponds to a gray value;
converting the gray value corresponding to each pixel point into the size of a unit region on the silicon oxide layer corresponding to the pixel point position;
outputting a vector graph according to the sizes of all the unit areas, wherein the vector graph comprises the shapes and the sizes of all the unit areas corresponding to each pixel point of the preset pattern;
inputting the vector graph into a laser marking machine, guiding the laser beam direction of the laser marking machine by using the vector graph, and ablating from the silicon oxide layer to the silicon layer direction to form a plurality of notches corresponding to the vector graph in a plurality of unit areas on the silicon oxide layer, thereby preparing and obtaining the silicon oxide etching template.
2. The method according to claim 1, wherein before converting the gray scale value corresponding to each pixel point into the size of the unit region on the silicon oxide layer corresponding to the pixel point position, the method further comprises the following steps:
opening the preset pattern by using programming software, and reading a gray matrix corresponding to the preset pattern, wherein the gray matrix comprises a gray value corresponding to each pixel point;
outputting a vector graphic according to the sizes of all the unit areas comprises the following steps:
outputting a vector graphic file containing the sizes of all unit areas on the silicon oxide layer;
and drawing the corresponding vector graphics in the vector graphics file in a plane drawing software according to the vector graphics file.
3. The manufacturing method according to claim 1, further comprising the steps of, between outputting a vector pattern according to the sizes of all the unit areas and inputting the vector pattern into a laser marking machine:
parameters of the laser marking machine are adjusted so that the laser beam ablates only the silicon oxide layer in a subsequent step of ablation.
4. The method for preparing a composite material according to claim 3, wherein the parameters of the laser marking machine at least comprise the frequency, scanning speed, scanning frequency and Z-axis height of the laser marking machine;
the frequency range of the laser marking machine is 50-65kHz, the scanning speed range of the laser marking machine is 135-150mm/s, the scanning frequency range of the laser marking machine is 1-3 times, and the Z-axis height range of the laser marking machine is 40-60 mm.
5. The method for producing a composite material according to claim 1, wherein the shape of the unit area is selected to be a square or a circle.
6. A method of patterning a silicon substrate, comprising the steps of:
preparing a silicon oxide etching template by the preparation method of any one of claims 1 to 5;
and etching the silicon substrate at the plurality of notches by using the silicon oxide etching template through a wet etching method so as to form patterns which are visually consistent with the preset patterns on the silicon substrate.
7. The patterning method according to claim 6, wherein in the wet etching method, the etching solution is an alkaline solution, and the solute is an alkaline solute.
8. A silicon substrate prepared by the preparation method of any one of claims 1 to 5, wherein the silicon substrate has a first surface and a second surface opposite to the first surface, and the silicon substrate comprises:
a plurality of silicon microstructures having different reflectivities, each of the silicon microstructures comprising a plurality of silicon microcells having the same reflectivity, each of the silicon microcells being configured on the silicon substrate and etched to a predetermined depth from the first surface of the silicon substrate toward a direction close to the second surface; wherein
The number of each silicon microstructure and the arrangement mode of all the silicon micro units on the silicon substrate are determined according to a preset pattern, so that the pattern formed by all the silicon micro units is visually consistent with the preset pattern.
9. The silicon substrate of claim 8, wherein each silicon microcell in the plurality of silicon microstructures is the same shape; and is
The silicon microstructures of the same kind have the same size of each silicon microcell, and the silicon microstructures of different kinds have different sizes of each silicon microcell.
10. Use of a silicon substrate according to any one of claims 8 to 9 for a solar cell.
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