A carrier plate for silver copper paste laser transfer printing and a preparation method thereof

Abstract

The application provides a carrier plate for silver-copper paste laser transfer printing and a preparation method thereof. The carrier plate comprises a substrate, and the substrate has a first surface. The first surface has a strip-shaped microgroove structure arranged periodically along a first direction and extending along a second direction. The first surface also has a hydrophobic layer. The static contact angle of the first surface to the silver-copper paste is θ, and 55°≤θ≤75°. The arithmetic average roughness of the first surface is Ra, and 0.3 μm≤Ra≤1.2 μm. The average spacing of adjacent rough peaks on the first surface is Rsm, and the particle size corresponding to the cumulative particle size distribution number of 99% of conductive particles in the silver-copper paste is D99. The following conditions are met: Rsm≥2×D99, so that the silver-copper paste realizes silver-coated copper ultra-fine grid line forming after being printed on the carrier plate.

Description

Technical Field

[0001] This application relates to the field of solar cells, and more particularly to a carrier plate for laser transfer of silver-copper paste and a method for preparing the same. Background Technology

[0002] Laser transfer technology is an emerging grid line fabrication technology. Its principle is as follows: conductive paste is filled into the grooves of a carrier plate, and the conductive paste is transferred to the surface of the solar cell by laser pulses. The carrier is a transfer film or a glass substrate.

[0003] Although laser transfer technology has the advantages of simple process and recyclable substrate, for silver-clad copper grid lines, the current laser transfer process is difficult to produce ultra-fine silver-clad copper grid lines, such as silver-clad copper grid lines with a linewidth of less than 20μm, due to the limitations of the substrate performance. Summary of the Invention

[0004] To address the aforementioned technical problems, this application discloses a carrier plate for laser transfer of silver-copper paste and its preparation method, enabling the formation of silver-copper-clad copper ultrafine grid lines after the silver-copper paste is printed on the carrier plate.

[0005] In a first aspect, this application provides a carrier plate for laser transfer of silver-copper paste, comprising: A substrate having a first surface; The first surface has a strip-shaped microgroove structure that is periodically arranged along a first direction and extends along a second direction; The first surface also has a hydrophobic layer; The static contact angle of the first surface with the silver-copper paste is θ, where 55°≤θ≤75°; The arithmetic mean roughness of the first surface is Ra, where 0.3 μm ≤ Ra ≤ 1.2 μm; The average spacing between adjacent rough peaks on the first surface is Rsm, and the particle size corresponding to the cumulative particle size distribution number of conductive particles in the silver-copper paste reaching 99% is D99, satisfying: Rsm≥2×D99; The first direction is the length extension direction of the grid line formed by the silver-copper paste, and the second direction is the direction perpendicular to the first direction on the first surface.

[0006] In some embodiments of this application, the roughness of the first surface along the first direction is Ra. x Along the second direction, the roughness of the first surface is Ra. y Satisfying: Ra x >Ra y .

[0007] In some embodiments of this application, 0.8 μm ≤ Rax ≤1.2μm, 0.3μm≤Ra y ≤0.6μm.

[0008] In some embodiments of this application, 20μm≤Rsm≤50μm.

[0009] In some embodiments of this application, the width of the strip microgroove structure is W1, and the depth of the strip microgroove structure is D1, satisfying: 4μm≤W1≤20μm, 1μm≤D1≤5μm.

[0010] In some embodiments of this application, the thickness of the hydrophobic layer is H1, where 3nm ≤ H1 ≤ 10nm.

[0011] In some embodiments of this application, the hydrophobic layer covers the first surface and the strip-shaped microgroove structure.

[0012] In some embodiments of this application, the material of the hydrophobic layer includes at least one of fluorosilane system materials and fluoropolymer system materials.

[0013] In some embodiments of this application, the fluorosilane system material includes at least one of perfluorooctyltriethoxysilane and perfluorodecyltrichlorosilane; The fluoropolymer system material includes a mixture of polytetrafluoroethylene nanoparticles and fluorinated acrylic resin.

[0014] In some embodiments of this application, the hydrophobic layer includes an anchoring underlayer and a hydrophobic toplayer, wherein the anchoring underlayer is in contact with the substrate.

[0015] In some embodiments of this application, the material of the anchoring substrate includes at least one of aminosilanes, organosilicon resins, polysiloxanes, high-temperature resistant polymers, and inorganic nano-oxides; The material of the hydrophobic top layer includes at least one of perfluorooctyltriethoxysilane and perfluorodecyltrichlorosilane.

[0016] Secondly, this application provides a method for preparing a carrier plate for laser transfer of silver-copper paste as described in the first aspect, comprising the following steps: A substrate is provided, the substrate having a first surface; Multiple strip-shaped microgrooves are formed on the first surface, arranged periodically along the first direction and extending along the second direction; The hydrophobic layer is prepared on the first surface after the strip microgroove structure is formed.

[0017] In some embodiments of this application, the strip microgroove structure is formed based on a first sandblasting process, a chemical etching process, or a laser etching process.

[0018] In some embodiments of this application, the preparation method further includes: The roughness of the first surface is controlled by a second sandblasting process.

[0019] Thirdly, this application provides a photovoltaic module, which includes a solar cell as described in the first aspect, or the photovoltaic module includes a solar cell prepared by the preparation method described in the second aspect.

[0020] Compared with the prior art, this application has at least the following beneficial effects: This application provides a carrier plate for laser transfer of silver-copper paste and its preparation method. The carrier plate has a first surface with strip-shaped microgrooves arranged periodically along a first direction and extending along a second direction, and also has a hydrophobic layer. Furthermore, the static contact angle of the first surface with the silver-copper paste is θ, 55°≤θ≤75°; the arithmetic mean roughness of the first surface is Ra, 0.3μm≤Ra≤1.2μm; the average spacing between adjacent roughness peaks of the first surface is Rsm; and the particle size corresponding to a cumulative particle size distribution of 99% of the conductive particles in the silver-copper paste is D99, satisfying: Rsm≥2×D99. In summary, by setting the strip-shaped microgrooves and hydrophobic layer on the first surface, and synergistically controlling θ, Ra, and Rsm within the scope of this application, this application enables the formation of ultra-fine silver-coated copper grid lines after the silver-copper paste is printed on the carrier plate, for example, achieving grid line width formation of less than 20μm, and achieving high-yield removal of the conductive paste in subsequent transfer steps. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the carrier plate in one embodiment of this application; Figure 2 This is a schematic diagram of the carrier plate in another embodiment of this application; Figure 3 This is a schematic diagram of the contact angle in one embodiment of this application; Figure 4 This is a strip microgroove structure in one embodiment of this application; Figure 5 This is a schematic diagram of the hydrophobic layer in one embodiment of this application; Explanation of reference numerals in the attached drawings: 1-substrate, 2-strip microgroove structure, 3-hydrophobic layer, 11-first surface, 31-anchoring bottom layer, 32-hydrophobic top layer. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0025] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0026] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0027] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0028] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0029] Heterojunction (HJT) solar cells have become an important technology in the photovoltaic industry due to their high conversion efficiency and low-temperature processing characteristics. Reducing the cost of metallization is the core objective of HJT solar cell industrialization, and replacing pure silver paste with silver-coated copper paste is one of the mainstream cost-reduction directions. However, as the linewidth of the steel plate opening narrows to below 20μm, the paste spreads laterally after printing onto the glass, resulting in an actual linewidth much larger than the steel plate opening linewidth, making it impossible to achieve ultra-fine line transfer below 20μm. Compared to pure silver paste, silver-copper paste has a higher copper powder density, approximately 8.9 g / cm³. 3 The high particle hardness of copper powder makes it prone to the presence of large-diameter copper powder particles (e.g., 10μm D99 copper powder particles). The Vickers hardness of copper powder is approximately 80HV~100HV, and the D50 particle size is typically 1μm~5μm. Furthermore, the surface of copper powder is easily oxidized to form CuO, which can lead to: 1) a 15%~25% difference in surface tension between the silver-copper paste and pure silver paste; 2) significant differences in wetting behavior between the silver-copper paste and the glass interface; and 3) high-density particles easily settling during rheological processes, exacerbating uneven spreading. On the other hand, in related technologies, surface modification of coated glass for laser transfer (e.g., anti-reflective (AR) film glass) mainly focuses on optimizing optical transmittance, without selectively improving the paste's formability. Its surface energy (approximately 40mJ / m²) is relatively low. 2 ~60mJ / m 2 The wetting parameters of the silver-copper paste do not match, resulting in uncontrolled spreading of the silver-copper paste.

[0030] In view of this, firstly, this application provides a carrier plate for laser transfer of silver-copper paste. See also Figure 1 and Figure 2 The carrier plate includes a substrate 1 having a first surface 11. The first surface 11 has strip-shaped microgrooves 2 periodically arranged along a first direction and extending along a second direction. The first surface 11 also has a hydrophobic layer 3. (Reference) Figure 3 The first surface 11 with a hydrophobic layer has a static contact angle θ with the silver-copper paste, where 55°≤θ≤75°. The arithmetic mean roughness of the first surface 11 is Ra, where 0.3μm≤Ra≤1.2μm. The average spacing between adjacent roughness peaks of the first surface 11 is Rsm. The particle size corresponding to a cumulative particle size distribution of 99% of the conductive particles in the silver-copper paste is D99, satisfying: Rsm≥2×D99. The substrate can be planar float glass or glass coated with an anti-reflective (AR) film, with a substrate thickness of 3mm~10mm.

[0031] In this application, the arithmetic mean roughness Ra refers to the arithmetic mean of the absolute values ​​of the profile offsets within the sampling length of the first surface. It is used to reflect the overall average height of the surface roughness and comprehensively reflect the degree of undulation of the surface peaks and valleys. The larger the value, the rougher the surface.

[0032] The inventors discovered that θ, Ra, and Rsm jointly affect the transfer quality of silver-copper paste. If θ is too small, the spread linewidth of the silver-copper paste is easily out of control; if θ is too large, the silver-copper paste is unable to form a continuous line, resulting in beading and broken lines; if Ra is too small, it is difficult to provide mechanical anchoring for the silver-copper paste, thus making it difficult to prevent the silver-copper paste from migrating laterally under the action of gravity and surface tension; if Ra is too large, it will cause the silver-copper paste to seep into the valley, that is, the microscopic depression area formed by roughness on the first surface of the carrier, increasing the actual contact area and thus exacerbating the spread of the silver-copper paste; D99 can reflect the size range of the largest particles in the silver-copper paste. Rsm≥2×D99 can avoid large-diameter copper powder particles in the silver-copper paste being mechanically stuck by rough peaks, resulting in residues after transfer that affect the transfer quality. This application provides a carrier plate for laser transfer of silver-copper paste. By setting a strip-shaped microgroove structure and a hydrophobic layer on the first surface, and synergistically controlling θ, Ra and Rsm within the scope of this application, the silver-copper paste can achieve the formation of ultra-fine silver-coated copper grid lines after printing on the carrier plate. For example, it can achieve grid line width formation of less than 20 μm, and achieve high yield of silver-copper paste removal in subsequent transfer steps.

[0033] In this application, the first direction is the length extension direction of the grid line formed by the silver-copper paste, and the second direction is the direction perpendicular to the first direction on the first surface.

[0034] In some embodiments of this application, reference is made to Figure 1 Along the first direction, the roughness of the first surface 11 is Ra. x Along the second direction, the roughness of the first surface 11 is Ra. y Satisfying: Ra x >Ra y The first direction is the direction of the squeegee movement, which is also the printing / transfer direction of the silver-copper paste. This is achieved by adjusting Ra... x >Ra y That is, by adjusting the directionality of the roughness texture, the higher roughness in the first direction of the carrier plate can provide anchoring force for the silver-copper paste to prevent the silver-copper paste from spreading out of control laterally, while the lower roughness in the second direction helps to ensure the continuity of the grid line shape.

[0035] In this application, Ra x Ra refers to the surface roughness value of the first surface measured along the first direction; y Ra refers to the surface roughness value of the first surface measured along the second direction. x and Ra y These are used to characterize the arithmetic mean roughness Ra in a specific measurement direction.

[0036] In some embodiments of this application, 0.8 μm ≤ Ra x≤1.2μm, 0.3μm≤Ra y ≤0.6μm. For example, Ra x 0.8μm, 0.9μm, 1μm, 1.1μm or 1.2μm; Ra y The thicknesses are 0.3 μm, 0.4 μm, 0.5 μm, or 0.6 μm. Ra x and Ra y Within the aforementioned range, the carrier plate has a higher roughness in the first direction, thereby providing stronger mechanical constraint in the direction perpendicular to the grid lines, inhibiting the lateral spread of the silver-copper paste, and achieving linewidth narrowing. Conversely, it has a lower roughness in the second direction, reducing the resistance of the scraper movement and ensuring the uniformity of the silver-copper paste filling. In this way, while ensuring the continuity of the grid line shape, it still provides effective anchoring capability for the silver-copper paste.

[0037] In some embodiments of this application, 20μm ≤ Rsm ≤ 50μm. For example, Rsm is 20μm, 30μm, 40μm, or 50μm. Rsm within this range can prevent large-diameter copper powder particles in the silver-copper paste, such as 10μm D99 copper powder particles, from being mechanically trapped by coarse peaks, thus avoiding residues after transfer that affect transfer quality. It also maintains sufficient anchor point density and surface structure uniformity, thereby synergistically achieving high-precision forming and high-yield transfer of the silver-copper paste with θ and Ra.

[0038] In some embodiments of this application, reference is made to Figure 4 The width of the strip microgroove structure 2 is W1, and the depth of the strip microgroove structure 2 is D1, satisfying: 4μm≤W1≤20μm, 1μm≤D1≤5μm. For example, W1 can be 4μm, 5μm, 10μm, 15μm, or 20μm, and D1 can be 1μm, 2μm, 3μm, 4μm, or 5μm. W1 and D1 being within the above ranges is beneficial for precisely controlling Rsm and the directionality of the roughness texture.

[0039] In some embodiments of this application, reference is made to Figure 4 The thickness of the hydrophobic layer is H1, where 3nm ≤ H1 ≤ 10nm. For example, H1 can be 3nm, 5nm, 7nm, or 10nm. The hydrophobic layer is a nanometer-thick thin film that controls the static contact angle of the first surface with the silver-copper paste, and its nanometer-thickness has almost no impact on the function of the strip microgroove structure.

[0040] In some embodiments of this application, reference is made to Figure 2 The hydrophobic layer 3 covers the first surface 11 and the strip microgroove structure 2, thereby modifying the first surface to be hydrophobic and thus controlling the contact angle of the silver-copper paste.

[0041] In some embodiments of this application, the hydrophobic layer material includes at least one of fluorosilane system materials and fluorinated polymer system materials. Since the laser pulse generates instantaneous high temperatures locally on the carrier surface during the laser transfer process of the silver-copper paste, with surface temperatures reaching 200°C to 400°C, the hydrophobic layer material should have a high thermal decomposition temperature: ≥300°C; and laser pulse tolerance: after 100,000 laser pulses, the contact angle attenuation rate should be ≤15%. Based on this, a polytetrafluoroethylene (PTFE) based system is preferred, with a thermal decomposition temperature of approximately 500°C; or, a fluorosilane self-assembled monolayer (SAM) with a CF bond energy of approximately 544 kJ / mol.

[0042] In some embodiments of this application, the fluorosilane system material includes at least one of perfluorooctyltriethoxysilane and perfluorodecyltrichlorosilane; the fluorinated polymer system material includes a mixture of polytetrafluoroethylene nanoparticles (D50 of 50 nm to 200 nm) and fluorinated acrylic resin. The weight-average molecular weight of the fluorinated acrylic resin is 100,000 to 500,000.

[0043] In some embodiments of this application, reference is made to Figure 5 The hydrophobic layer 3 includes an anchoring bottom layer 31 and a hydrophobic top layer 32, with the anchoring bottom layer 31 in contact with the substrate 1. The thickness of the anchoring bottom layer is 1nm~2nm, and the thickness of the hydrophobic top layer is 2nm~5nm, forming a double-layer gradient structure to improve the bonding force between the overall hydrophobic layer and the substrate.

[0044] In some embodiments of this application, the material of the anchoring layer includes at least one of aminosilanes, organosilicon resins, polysiloxanes, high-temperature resistant polymers, and inorganic nano-oxides; the material of the hydrophobic top layer includes at least one of perfluorooctyltriethoxysilane and perfluorodecyltrichlorosilane.

[0045] Secondly, this application provides a method for preparing a carrier plate for laser transfer of silver-copper paste as described in the first aspect, comprising the following steps: Step A: Provide a substrate having a first surface; Step B: Create multiple strip-shaped microgrooves on the first surface, arranged periodically along the first direction and extending along the second direction; Step C: Prepare a hydrophobic layer on the first surface after forming the strip microgroove structure.

[0046] In step A, the substrate can be ultra-white float glass, which is prepared for use after RCA cleaning or ultrasonic cleaning. The ultrasonic cleaning process parameters are as follows: the cleaning solution is a mixture of deionized water and ethanol, the frequency is 35kHz~45kHz, and the time is 8min~12min; the drying temperature is 110℃~130℃, and the drying time is 25min~35min.

[0047] In step C, when the hydrophobic layer consists of an anchoring underlayer and a hydrophobic top layer, an anchoring underlayer based on 3-aminopropyltriethoxysilane (APTES) can be first formed on the substrate surface using a vapor deposition process, followed by a hydrophobic top layer based on tridecafluorooctyltriethoxysilane (PFOTES) formed on the surface of the anchoring underlayer using a vapor deposition process; alternatively, a hydrophobic top layer based on PTFE nanoparticles can be coated on the surface of the anchoring underlayer. The average particle size of the PTFE nanoparticles is 50 nm to 100 nm. The mass ratio of PTFE nanoparticles to fluorinated acrylic resin affects the performance of the hydrophobic layer, thereby affecting the static contact angle θ of the first surface with the silver-copper paste. For example, as the relative content of PTFE nanoparticles in the hydrophobic layer increases, θ initially increases and then tends to stabilize (when the PTFE content is too high, particle agglomeration may lead to a decrease in roughness or a deterioration in coating uniformity, causing θ to tend to stabilize or slightly decrease). Based on this, θ can be controlled by adjusting the mass ratio of PTFE nanoparticles to fluorinated acrylic resin.

[0048] In some embodiments of this application, the strip microgroove structure is formed based on a first sandblasting process, a chemical etching process, or a laser etching process.

[0049] In this application, the methods for forming the strip-shaped microgroove structure include, but are not limited to, borax etching, chemical etching, or laser micromachining. For example, the borax etching process can use Al2O3 abrasive (80-200 mesh) at a pressure of 0.1 MPa-0.3 MPa, placing a strip-shaped mask on the substrate to expose the sandblasting contact area, thereby forming the strip-shaped microgroove structure. Another example is the chemical etching process, which uses HF / NH4F buffer solution (pH 4-5, 25℃-40℃), requiring the formation of a strip-shaped opening pattern through a mask before etching with the buffer solution to form the strip-shaped microgroove structure. Yet another example is the laser micromachining process, which uses a femtosecond laser to etch the strip-shaped microgroove structure onto the substrate, with a laser pulse width of less than 200 fs and a repetition frequency of 1 kHz-10 kHz.

[0050] In some embodiments of this application, the preparation method further includes: The roughness of the first surface is controlled by a second sandblasting process.

[0051] In this application, the arithmetic mean roughness Ra of the first surface can be controlled by sandblasting the first surface of the substrate, i.e., by employing a second sandblasting process. The arithmetic mean roughness Ra of the first surface can be adjusted by adjusting process parameters such as abrasive particle size, blasting pressure, and blasting distance. The average spacing Rsm between adjacent roughness peaks can be controlled by adjusting the distance between two adjacent strip-shaped microgroove structures.

[0052] Thirdly, this application provides a photovoltaic module, the photovoltaic module including a solar cell, the solar cell having grid lines formed using a carrier plate for laser transfer of silver-copper paste as described in any of the above embodiments.

[0053] This application also provides a photovoltaic module for converting received light energy into electrical energy and transmitting it to an external load. The photovoltaic module includes: at least one cell string, which is composed of multiple solar cells connected together; an encapsulating film for covering the surface of the cell string; and a cover plate for covering the surface of the encapsulating film facing away from the cell string.

[0054] Example The carrier plate for laser transfer of silver-copper paste according to the present application embodiment will be further described below with reference to more specific embodiments.

[0055] Example 1 <Substrate Processing> A 5mm thick ultra-white float glass is provided as the substrate, with a strain point ≥550°C. White corundum powder with an average particle size of 63μm is used. The spraying pressure is 0.3MPa, the spraying distance is 150mm, and the spraying angle is 90°, i.e., perpendicular incident and isotropic. This controls the arithmetic mean roughness Ra of the first surface of the substrate and the average spacing between adjacent roughness peaks to Rsm.

[0056] <Preparation of strip-shaped microgroove structures> Laser etching is used to form strip-shaped microgrooves on the substrate surface. By controlling the depth, width, and spacing of the microgrooves, the Ra value can be adjusted. x and Ra y ; <Preparation of Hydrophobic Layer> A hydrophobic layer was formed on the first surface by spin coating and thermosetting of a mixed dispersion of PTFE nanoparticles and fluorinated acrylic resin. The PTFE nanoparticle dispersion had a solid content of 5 wt%, the mass ratio of PTFE nanoparticles to fluorinated acrylic resin was 4:1, and the solvent was perfluoropolyether (PFPE). The spin coating parameters were: first, 500 rpm for 5 seconds to spread the PTFE nanoparticle dispersion, then 3000 rpm for 30 seconds to form a film. The thermosetting process involved pre-drying at 80°C for 10 minutes to remove the solvent, followed by sintering at 380°C for 30 minutes, with a cooling rate ≤5°C / min to prevent cracking of the hydrophobic layer due to thermal stress.

[0057] Examples 2-3 Except for adjusting the arithmetic mean roughness Ra of the first surface and the average spacing between adjacent roughness peaks to Rsm according to Table 1 in the <Substrate Processing>, the rest is the same as in Example 1.

[0058] Examples 4-5 In addition to the section on "Preparation of Strip Microgroove Structures," where the depth and width of the strip microgroove structure are adjusted to control Ra according to Table 1, the following steps are also taken: x and Ra y Except for the above, it is the same as in Example 1.

[0059] Examples 6-7 Except for the preparation of the hydrophobic layer, in which the mass ratio of PTFE nanoparticles to fluorinated acrylic resin is adjusted to control the static contact angle θ of the first surface with the silver-copper paste according to Table 1, the rest is the same as in Example 1.

[0060] Comparative Examples 1 to 2 Except for adjusting the arithmetic mean roughness Ra of the first surface and the average spacing between adjacent roughness peaks to Rsm according to Table 1 in the <Substrate Processing>, the rest is the same as in Example 1.

[0061] Comparative Examples 3 to 4 In addition to the section on "Preparation of Strip Microgroove Structures," where the depth and width of the strip microgroove structure are adjusted to control Ra according to Table 1, Ra is also controlled. x and Ra y Except for the above, the rest is the same as in Example 1.

[0062] Comparative Examples 5 to 6 Except for adjusting the arithmetic mean roughness Ra of the first surface and the average spacing between adjacent roughness peaks to Rsm according to Table 1 in the <Substrate Processing>, the rest is the same as in Example 1.

[0063] Table 1: Preparation parameters for each example and comparative example

[0064] Performance testing: The carriers prepared in each embodiment and comparative example were subjected to grid line transfer. Specifically, the viscosity of the silver-copper paste was adjusted to 200 Pa·s, and a two-step transfer process was adopted. First, the silver-copper paste was transferred from a steel plate to the carrier plate, where the opening linewidth of the steel plate was 28 μm and the depth was 18 μm; the squeegee pressure was 0.28 MPa, the squeegee moving speed was 70 mm / s, and the grid linewidth of the silver-copper paste after transfer to the carrier plate was 24 μm ± 1.2 μm. Second, the silver-copper paste was transferred from the carrier plate to the surface of the blue film (mainly a transparent conductive oxide film layer, such as a TCO film layer) of the HJT solar cell using a laser transfer process. The laser parameters were: wavelength 1064 nm, pulse width 80 ns, and energy density 1.0 J / cm². 2 The scanning speed was 400 mm / s. The transferred linewidth, broken grid rate, transfer yield, and residue on the carrier plate were then tested. The abrasion resistance of the hydrophobic layer and the carrier plate life were also tested. Among these: The process for testing the abrasion resistance of the hydrophobic layer is as follows: Test steps: 1. Contact angle measurement of silver-coated copper paste: Using a contact angle measuring instrument, randomly select 5 positions on the first surface of the carrier board and measure the static contact angle of the silver-coated copper paste (with the same formula as the subsequent process). Record the average value as θ. 浆 Judgment criterion: θ 浆 =55°~75°. 2. Initial contact angle measurement: Using a contact angle measuring instrument (e.g., Krüss DSA100), randomly select 5 positions on the first surface of the carrier plate to measure the static contact angle of deionized water, and record the average value as θ0; 3. Friction treatment: ① RCA paper tape method: Fix the carrier plate on the test bench, use a special paper tape (width 6.4mm, load 175g), and rub it back and forth 100 times along the second direction (perpendicular to the grid line direction) on the hydrophobic layer surface, with a rubbing distance of 20mm and a speed of 30 times / min; 4. Contact angle measurement after friction: Measure the static contact angle again at the same position, and record the average value as θ1; 5. Calculate the attenuation rate: Contact angle attenuation rate = (θ0-θ1) / θ0×100%; 6. Judgment criteria: Contact angle θ of silver-coated copper paste 浆 55°~75° (pass), attenuation rate ≤15% is acceptable. Deionized water cannot be simply replaced with silver-coated copper paste because the testing purposes are different; adjustments have been made accordingly.

[0065] The carrier board life test process is as follows: Test equipment: Laser transfer experimental platform (including nanosecond laser, wavelength 532nm, pulse width 10ns, spot diameter 30μm), screen printing machine, microscope.

[0066] Test Procedure: 1. Initial Performance Calibration: 1) Using standard silver-copper paste (D99=10μm, solid content 85wt%), print grid lines on a substrate (target line width 18μm, length 100mm); 2) Perform laser transfer (laser energy density 0.5J / cm²). 2 The pulse frequency is 10kHz), and the transfer is performed on the polished silicon wafer; the initial transfer yield (≥95% is acceptable) and the initial printed linewidth (≤20μm is acceptable) are measured. 2. Cyclic Test: Repeat the following steps until the transfer yield is below 90%: Step 1: Gently wipe the surface of the carrier plate with a lint-free cloth dampened with isopropyl alcohol to remove residual paste (be careful not to damage the hydrophobic layer); Step 2: After drying with nitrogen, check the surface under a microscope for scratches, microgroove blockage, or hydrophobic layer peeling; Step 3: Re-print and laser transfer, recording the transfer yield, printed line width, and residual particle rate each time; after every 1000 transfers, measure the contact angle θ and record the attenuation. 3. Lifespan Determination: When the transfer yield is below 90% in three consecutive tests, or the printed linewidth exceeds 25μm, or the contact angle decay rate exceeds 15%, the carrier board is considered to have reached its lifespan end. The cumulative number of transfers at the end of the lifespan is recorded as the carrier board's lifespan. 4. Data Recording: Plot a transfer yield-transfer count curve, taking the number of times the yield first falls below 90% as the lifespan value; simultaneously record auxiliary data such as contact angle decay rate and surface morphology changes (SEM observation).

[0067] Table 2: Performance data of each embodiment and comparative example

[0068] As can be seen from Examples 1 to 7 and Comparative Examples 1 to 6, the transfer linewidth of Examples 1 to 7 was controlled at 16μm to 24μm, the grid breakage rate was not higher than 1.20%, the transfer yield was not lower than 92.5%, the residue rate was not higher than 2.0%, and the carrier life was ≥32,000 cycles, achieving the formation of ultra-fine silver-clad copper grid lines with excellent overall performance. However, Comparative Examples 1 to 6 showed that the transfer linewidth was too narrow or too wide, that is, the transfer linewidth was out of control, the grid breakage rate increased to 2.8% to 6.0%, the transfer yield decreased to 65% to 85%, the residue rate increased to 1.5% to 4.0%, and the carrier life was significantly shortened to ≤25,000 cycles.

[0069] The above provides a detailed description of a carrier plate for laser transfer of silver-copper paste and its preparation method disclosed in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core inventive points of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A carrier plate for laser transfer of silver-copper paste, characterized in that, include: A substrate having a first surface; The first surface has a strip-shaped microgroove structure that is periodically arranged along a first direction and extends along a second direction; The first surface also has a hydrophobic layer; The static contact angle of the first surface with the silver-copper paste is θ, where 55°≤θ≤75°; The arithmetic mean roughness of the first surface is Ra, where 0.3 μm ≤ Ra ≤ 1.2 μm; The average spacing between adjacent rough peaks on the first surface is Rsm, and the particle size corresponding to the cumulative particle size distribution number of conductive particles in the silver-copper paste reaching 99% is D99, satisfying: Rsm≥2×D99; The first direction is the length extension direction of the grid line formed by the silver-copper paste, and the second direction is the direction perpendicular to the first direction on the first surface.

2. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, Along the first direction, the roughness of the first surface is Ra. x Along the second direction, the roughness of the first surface is Ra. y Satisfying: Ra x >Ra y .

3. The carrier plate for laser transfer of silver-copper paste according to claim 2, characterized in that, 0.8μm≤Ra x ≤1.2μm,0.3μm≤Ra y ≤0.6μm。 4. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, 20μm≤Rsm≤50μm.

5. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, The width of the strip microgroove structure is W1, and the depth of the strip microgroove structure is D1, satisfying: 4μm≤W1≤20μm, 1μm≤D1≤5μm.

6. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, The thickness of the hydrophobic layer is H1, where 3nm ≤ H1 ≤ 10nm.

7. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, The hydrophobic layer covers the first surface and the strip-shaped microgroove structure.

8. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, The hydrophobic layer is made of at least one of fluorosilane-based materials and fluoropolymer-based materials.

9. The carrier plate for laser transfer of silver-copper paste according to claim 8, characterized in that, The fluorosilane system material includes at least one of perfluorooctyltriethoxysilane and perfluorodecyltrichlorosilane; The fluoropolymer system material includes a mixture of polytetrafluoroethylene nanoparticles and fluorinated acrylic resin.

10. The carrier plate for laser transfer of silver-copper paste according to claim 1, characterized in that, The hydrophobic layer includes an anchoring bottom layer and a hydrophobic top layer, wherein the anchoring bottom layer is in contact with the substrate.

11. The carrier plate for laser transfer of silver-copper paste according to claim 10, characterized in that, The material of the anchoring layer includes at least one of aminosilanes, organosilicon resins, polysiloxanes, high-temperature resistant polymers, and inorganic nano-oxides; The material of the hydrophobic top layer includes at least one of perfluorooctyltriethoxysilane and perfluorodecyltrichlorosilane.

12. A method for preparing a carrier plate for laser transfer of silver-copper paste as described in any one of claims 1 to 11, characterized in that, Includes the following steps: A substrate is provided, the substrate having a first surface; Multiple strip-shaped microgrooves are formed on the first surface, arranged periodically along the first direction and extending along the second direction; The hydrophobic layer is prepared on the first surface after the strip microgroove structure is formed.

13. The preparation method according to claim 12, characterized in that, The strip-shaped microgroove structure is formed based on a first sandblasting process, a chemical etching process, or a laser etching process.

14. The preparation method according to claim 12, characterized in that, The preparation method further includes: The roughness of the first surface is controlled by a second sandblasting process.

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