Nanometer modified anti-soldering ink for SLP carrier board and preparation method thereof

Abstract

The application discloses a kind of SLP class nano-modified solder resist ink for carrier plate and preparation method thereof, belong to new material technical field.For the problems such as insufficient adhesion, poor heat resistance, poor chemical resistance and low resolution of existing solder resist ink in SLP class carrier plate manufacturing, the application is composed of composite nano filler by nano silicon dioxide modified by silane coupling agent, copper-containing MOF seed and two-dimensional transition metal carbide sheet layer, combined with photoinitiator compound, trimethylolpropane triacrylate and perfluorooctanoic acid and other functional additives, using ultrasonic dispersion and magnetic field assisted directional curing process, form multistage pore structure and anisotropic crosslinking network.The adhesion of the obtained ink reaches 5B, there is no crack in 260 DEG C thermal shock, there is no adhesion drop in pH 3.5 sulfuric acid solution, the development line width reaches 45-50 μm, meet the high-precision, high reliability requirement of SLP class carrier plate.The preparation method process is simple, compatible with existing process, with environmental protection and economic benefit, suitable for high-end electronic manufacturing field.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically, it relates to a nano-modified solder resist ink for SLP type carriers and its preparation method. Background Technology

[0002] In the electronics manufacturing field, SLP (Substrate-Like PCB) substrates, as a type of high-density, high-precision, and high-reliability circuit board, have been widely used in high-end electronic products such as smartphones, tablets, and wearable devices in recent years. SLP substrates combine the technical characteristics of traditional PCBs (Printed Circuit Boards) and FPCs (Flexible Printed Circuits), possessing a substrate-like structure that enables higher integration and finer linewidths / spacings (e.g., 50 / 50μm). Solder resist ink, a key material in the manufacturing process of SLP substrates, is primarily used to protect the copper conductors on the circuit board surface, preventing short circuits during soldering, while also providing insulation and protection. However, with the increasing performance requirements of SLP substrates, traditional solder resist inks have revealed numerous technical defects in practical applications, including insufficient adhesion, poor heat resistance, poor chemical resistance, and low development resolution. These problems severely limit the further development of SLP substrates in high-precision, high-reliability manufacturing.

[0003] In SLP (Selective Plating) substrate manufacturing, ultra-roughened copper surface treatment technology is typically used to enhance interlayer adhesion and signal transmission stability, achieving a surface roughness (Ra) of 0.5-1.0 μm. This high-roughness surface significantly increases the surface area and mechanical anchoring points, contributing to improved material bonding. However, traditional solder resist inks exhibit poor adhesion on such ultra-roughened copper surfaces. Due to insufficient interfacial adhesion between the ink and the copper surface, the ink is prone to peeling off during subsequent processes (such as thermal shock, chemical treatment, or mechanical stress). For example, in selective electroplating (SOP) soft gold processes, solder resist inks need to withstand high temperatures and chemical corrosion; inks with insufficient adhesion may peel off under these harsh conditions, leading to decreased circuit board reliability and even affecting yield and lifespan.

[0004] The manufacturing of SLP substrates involves multiple high-temperature processing steps, such as pre-baking of solder resist ink (approximately 80-120°C), post-baking (approximately 150-180°C), and reflow soldering (peak temperature can reach 260°C). Traditional solder resist inks are prone to thermal decomposition, cracking, or blistering under high-temperature environments, especially during the 260°C reflow soldering thermal shock test, where cracks and bubbles often appear on the ink surface. These defects not only weaken the ink's protective function for the circuit board but may also cause internal short circuits or signal interference, severely affecting the performance and long-term stability of SLP substrates.

[0005] During the manufacturing process of SLP substrates, solder resist inks undergo various chemical treatments, including developing solutions (usually alkaline solutions), micro-etching solutions (acidic solutions), and chemical etching during the electroplating of soft gold. Traditional solder resist inks are prone to chemical degradation in acidic or alkaline environments, leading to decreased performance, weakened adhesion, and even swelling or peeling. For example, after immersion in a sulfuric acid solution with a pH of 3.5, the adhesion grade of traditional inks (tested according to ASTM D3359 standard) often drops by 1-2 grades. This not only reduces manufacturing yield but may also pose a threat to the long-term reliability of SLP substrates.

[0006] As the linewidth / spacing of SLP-type substrates continues to decrease, higher demands are placed on the development resolution of solder resist inks. Traditional solder resist inks, due to insufficient photocuring efficiency or uneven filler distribution during exposure and development, often result in blurred pattern edges, with the minimum resolvable linewidth typically between 60-80 μm. This is insufficient to meet the 50 / 50 μm or even finer linewidth requirements of SLP-type substrates. This inadequate development resolution limits the application of SLP-type substrates in high-density interconnect (HDI) technology, impacting the integration density and performance improvement of circuit boards.

[0007] To address the aforementioned issues, several improvement solutions have been proposed in existing technologies. For example: adding inorganic fillers: Inorganic fillers such as silica and calcium carbonate are added to the ink to improve its mechanical strength and heat resistance. Resin modification: Fluoropolymers or silane coupling agents are used to modify the resin to enhance adhesion and chemical resistance. Optimizing photoinitiators: The photoinitiator system is adjusted to improve development resolution and curing efficiency. However, these improvements still have significant limitations: poor filler dispersibility: Traditional inorganic fillers tend to agglomerate in the resin matrix, leading to uneven ink performance and affecting adhesion and development resolution. Insufficient compatibility: Fluoropolymers or silane coupling agents have poor compatibility with the resin matrix, which may cause instability in the ink system, affecting curing effect and long-term performance. Limitations of photoinitiators: A single photoinitiator system cannot simultaneously meet the requirements of high curing efficiency and excellent development resolution, especially in high-precision development. Summary of the Invention

[0008] 1. The problem to be solved

[0009] To address the aforementioned issues, this invention develops a nano-modified solder resist ink for SLP-type carriers. It combines composite nanofillers such as silane coupling agent-modified nano-sized silica particles, copper-containing metal-organic framework (MOF) seeds, and two-dimensional transition metal carbide sheets. Furthermore, it employs ultrasonic dispersion, functional additive formulation, and magnetic field-assisted directional curing processes to construct an ink system with a multi-level porous structure and anisotropic cross-linked network. This significantly improves adhesion (target 5B), heat resistance (no cracking), chemical resistance (ΔB=0), and development resolution (45-50μm), while ensuring process compatibility, environmental friendliness, and economic benefits, thus meeting the high-precision and high-reliability manufacturing requirements of SLP-type carriers.

[0010] 2. Technical Solution

[0011] To solve the above problems, the present invention adopts the following technical solution.

[0012] A method for preparing a nano-modified solder resist ink for SLP carriers includes the following steps: (1) Nano-reinforcing phase construction: Nano-sized silica particles modified with silane coupling agent are mixed with two-dimensional transition metal carbide sheets at a mass ratio of (3-6):1 and copper-containing metal-organic framework seed crystals are added. Intercalation assembly is performed at 40-60℃ to form a composite nanofiller with a multi-level porous structure; (2) Resin matrix modification: Epoxy resin prepolymer and trimethylolpropane triacrylate are compounded at a mass ratio of (5-8):1. 0.1-0.3 times the mass of epoxy resin prepolymer is added to the composite nanofiller obtained in step (1). Ultrasonic dispersion is performed to control the viscosity of the system in the range of 2000-5000cps to obtain a modified resin matrix; (3) Functional additive compounding: According to the weight By weight, for every 100 parts of modified resin matrix, the following system is added: 15-25 parts of phenolic curing agent, 0.5-2 parts of fluorinated surfactant, 1-3 parts of phosphate ester adhesion promoter, and 2-5 parts of photoinitiator complex. The photoinitiator complex is a mixture of benzophenone (CAS No. 119-61-9) and thioxanthone (CAS No. 492-22-8) in a ratio of (1-3):1, and finally a mixed system is obtained; (4) Directional curing molding: After grinding the mixed system to a fineness ≤5μm, it is subjected to gradient cooling treatment under a magnetic field strength of 0.1-0.5T. First, it is cooled to 20-30℃ below the glass transition temperature at a rate of 2-5℃ / min, and then rapidly cooled to room temperature to form an anisotropic cross-linked network, thereby obtaining nano-modified solder resist ink for SLP type carriers.

[0013] The preparation method of the nano-modified solder resist ink for SLP type carriers, the preparation method of the nano-sized silica particles modified by silane coupling agent in step (1) is as follows: γ-aminopropyltriethoxysilane (CAS No. 919-30-2) and vinyltrimethoxysilane (2768-02-7) are mixed at a molar ratio of (0.5-2):1, and an ethanol solution containing 0.1-0.5wt% sodium dodecylbenzenesulfonate (CAS No. 25155-30-0) is added at 5-10 times the mass of γ-aminopropyltriethoxysilane. The reaction is carried out in stages under nitrogen protection: First stage: ultrasonic-assisted hydrolysis at 25-35℃, frequency 40kHz, power 50W / L, 30-60min; Second stage: microwave-assisted condensation at 50-60℃, frequency 50kHz, power 80W / L, pressure 0.5MPa. a. After 2-4 hours, a modified system is obtained. A mixture of silica and 2-hydroxy-4-acryloyloxybenzophenone (CAS No. 15419-94-0) in a mass ratio of 1:(2-6) is introduced into the modified system, wherein the mass of the mixture is 30-40% of the modified system. A photoresponsive crosslinking network is formed by UV light initiation, wherein the UV light wavelength is 365 nm, the duration is 20-40 min, and the intensity is 80 mW / cm². 2 .

[0014] The preparation method of the nano-modified solder resist ink for SLP-type carriers, in step (1), the CAS number of the two-dimensional transition metal carbide sheet is 12363-89-2, and it is a 935883 product manufactured by Sigma-Aldrich, USA; the preparation method of the copper-containing metal-organic framework seed crystal in step (1) is as follows: copper chloride and 2,2'-bis(4-carboxyphenyl)hexafluoropropane (CA Mix the copper-containing metal-organic framework seed crystals (S No. 1171-47-7) at a molar ratio of (3-5):1, and add 1-3 times the mass of copper chloride in an N,N-dimethylformamide solution (CAS No. 68-12-2) containing 0.1-0.5 wt% sodium dodecyl sulfate. The reaction is carried out under nitrogen protection with ultrasonic assistance at a frequency of 40 kHz, an ultrasonic power of 50 W / L, and an ultrasonic time of 30-60 min. Then, a stepped temperature program is used for treatment: nucleation stage: 25-35℃ for 0.5-1 h with a stirring rate of 500 rpm; growth stage: rapid heating to 60-80℃ and holding for 2-4 h with a pressure of 0.5-1 MPa; ripening stage: gradient cooling (cooling rate of 2℃ / min) to 40-50℃ to complete crystal orientation, and copper-containing metal-organic framework seed crystals are obtained.

[0015] The preparation method of the nano-modified solder resist ink for SLP type carriers, the intercalation assembly process in step (1) is as follows: Silane coupling agent modified nano-sized silica particles are mixed with two-dimensional transition metal carbide sheets and added to anhydrous ethanol at 15-20 times the mass of the two-dimensional transition metal carbide sheets. The mixture is pre-dispersed for 20-40 min using a high-speed homogenizer at 8000-12000 rpm to form a uniform suspension. Copper-containing metal-organic framework seed crystals are added to the suspension, wherein the mass of the copper-containing metal-organic framework seed crystals is 10-20% of the mass of the two-dimensional transition metal carbide sheets. The mixture is transferred to a reaction vessel and treated under a nitrogen atmosphere: ultrasonic frequency 30 kHz, ultrasonic power 50 W / L, maintained at 40-50℃ for 30-60 min, pressure 0.3-0.5 MPa, and rapidly cooled to 25-35℃ to obtain the product.

[0016] The preparation method of the nano-modified solder resist ink for SLP type carriers, in step (2), the CAS number of the epoxy resin prepolymer is 1675-54-3, and the product number 31185 is produced by Sigma-Aldrich, USA; in step (2), the CAS number of trimethylolpropane triacrylate is 15625-89-5, and the product number 246808 is produced by Sigma-Aldrich, USA; the parameters of the ultrasonic dispersion treatment in step (2) are as follows: 20kHz, power 50-100W / L, time 5-30min.

[0017] The preparation method of the nano-modified solder resist ink for SLP type carriers, in step (3), the CAS number of the phenolic curing agent is 9003-35-4, the product number is P195710, and it is from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0018] In the preparation method of the nano-modified solder resist ink for SLP type carriers, the phosphate ester adhesion promoter in step (3) is triphenyl phosphate, CAS number 115-86-6.

[0019] In the preparation method of the nano-modified solder resist ink for SLP type carriers, the fluorinated surfactant in step (3) is perfluorooctanoic acid, CAS number 335-67-1.

[0020] A nano-modified solder resist ink for SLP-type carriers, wherein the nano-modified solder resist ink for SLP-type carriers is obtained by the preparation method described above.

[0021] 3. Beneficial effects

[0022] Compared to existing technologies, the advantages of this invention are as follows: Excellent adhesion: Through the composite nanofiller of silane coupling agent-modified nano-sized silica particles, copper-containing metal-organic framework (MOF) seeds, and two-dimensional transition metal carbide sheets, combined with intercalation assembly technology, a nano-reinforcing phase with a multi-level porous structure is formed, which significantly enhances the interfacial bonding force between the solder resist ink and the ultra-roughened copper surface of the SLP-type substrate. Test results show that the adhesion of Examples 1-18 all reached 5B (ASTM D3359 standard, no peeling), which is far superior to the 3B-4B of Comparative Examples 1-16, making it particularly suitable for the high precision and high reliability requirements of SLP-type substrates. Excellent heat resistance: The multi-level porous structure and anisotropic cross-linked network of the composite nanofiller (formed by magnetic field-assisted gradient cooling curing) effectively disperse thermal stress and prevent cracking and blistering at high temperatures. Examples 1-18 showed no cracks (crack length 0 μm) in the 260℃ reflow soldering thermal shock test (10s, 3 times), while Comparative Examples 1-16 showed cracks of 50-150 μm, demonstrating the high-temperature stability of the ink in post-processing of SLP substrates (such as selective electroplating soft gold). Excellent chemical resistance: The synergistic effect of copper MOF seed crystals and functional additives such as perfluorooctanoic acid enhances the chemical stability of the ink, especially in micro-etching and electroplating soft gold processes. Examples 1-18 showed no change in adhesion in a pH 3.5 sulfuric acid solution (48h) test (ΔB = 0), while the adhesion of Comparative Examples 1-16 decreased by 1-2 grades (ΔB = 1-2), indicating that the ink of the present invention can effectively resist chemical corrosion and extend the service life of SLP substrates. High developing resolution: The photoinitiator complex (benzophenone and thioxanthone) and trimethylolpropane triacrylate optimize photocuring efficiency and crosslinking density. Combined with ultrasonic dispersion, this ensures uniform filler distribution, enabling the ink to form clear pattern edges during development. Examples 1-18 exhibit a minimum resolvable linewidth of 45-50 μm, meeting the high-precision developing requirements of SLP substrates (linewidth / spacing 50 / 50 μm), significantly superior to the 60-80 μm of Comparative Examples 1-16. Process compatibility and stability: This invention forms an anisotropic crosslinked network through directional curing (magnetic field strength 0.1-0.5T, gradient cooling 2-5℃ / min), improving the mechanical strength and structural stability of the ink. It perfectly adapts to SLP substrate processes (material preparation, roughening, solder resist printing, pre-baking, exposure, development, post-baking, selective electroplating, etc.). Comparative Examples 14-16 lacked directional curing or magnetic field assistance, resulting in a significant performance degradation, verifying the necessity of the process in this invention. Environmental and Economic Benefits: The nano-modification technology and functional additive compounding process employed in this invention optimize material utilization efficiency and reduce the use of high-volatile organic compounds (VOCs) in traditional solder resist inks, thus meeting environmental protection requirements. Simultaneously, the superior performance reduces the defect rate in SLP-type substrate manufacturing, improving production efficiency and economic benefits.Wide applicability: By adjusting the ratio of composite nanofillers (nano silica and two-dimensional transition metal carbides 3:1 to 6:1), resin matrix ratio (epoxy resin and trimethylolpropane triacrylate 5:1 to 8:1), and the amount of functional additives (phenolic curing agent 15-25 parts, etc.), the ink of this invention can flexibly adapt to the process requirements of different SLP carriers, showing good process adaptability and application prospects.

[0023] The nano-modified solder resist ink for SLP-type carriers of the present invention significantly improves adhesion, heat resistance, chemical resistance, and development resolution through key technologies such as composite nanofillers, ultrasonic dispersion, functional additive compounding, and directional curing. This overcomes the shortcomings of traditional solder resist inks in the high-precision, high-reliability manufacturing of SLP-type carriers. Test results (comparison of Examples 1-18 and Comparative Examples 1-16) demonstrate that the ink of the present invention has significant technical advantages and application value in the manufacturing of SLP-type carriers. Attached Figure Description

[0024] Figure 1 This is a transmission electron microscope image of the composite nanofiller prepared in Example 3.

[0025] Figure 2 This is a scanning electron microscope image of the modified resin matrix prepared in Example 3.

[0026] Figure 3 This is a sample image of the nano-modified solder resist ink for SLP-type carriers prepared in Example 3. Detailed Implementation

[0027] The present invention will now be described in detail through specific embodiments. However, these illustrative embodiments are for the purpose of illustrating the invention only and do not constitute any limitation on the actual scope of protection of the invention, nor are they intended to limit the scope of protection of the invention to these embodiments. For parameter ranges not mentioned, intermediate values ​​are selected. Furthermore, for mass percentages or weight percentages not explicitly stated or mentioned, they generally refer to the final concentration after addition.

[0028] Example 1

[0029] Construction of the nano-reinforced phase: 0.5 g of γ-aminopropyltriethoxysilane and 1 g of vinyltrimethoxysilane (molar ratio 0.5:1) were mixed, and 5 g of an ethanol solution containing 0.1 wt% sodium dodecylbenzenesulfonate was added. A staged hydrolysis-condensation reaction was carried out under nitrogen protection. First stage: 25 °C, ultrasonic-assisted hydrolysis (40 kHz, 50 W / L, 30 min); Second stage: 50 °C, microwave-assisted condensation (50 kHz, 80 W / L, 0.5 MPa, 2 h) to obtain the modified system. 1.5 g of silica and 0.5 g of 2-hydroxy-4-acryloyloxybenzophenone (mass ratio 1:2, accounting for 30% of the modified system) were added to the modified system, and the mixture was exposed to 365 nm UV light (80 mW / cm²). 2 (20 min) to initiate the formation of a photoresponsive crosslinking network, resulting in nanoscale silica particles modified with a silane coupling agent.

[0030] 3g of silane coupling agent-modified nano-sized silica particles were mixed with 1g of two-dimensional transition metal carbide sheets (mass ratio 3:1), and 15g of anhydrous ethanol was added. The mixture was pre-dispersed using a high-speed homogenizer (8000rpm, 20min) to form a uniform suspension. 0.1g of copper-containing metal-organic framework seed crystals (3g of copper chloride and 1g of 2,2'-bis(4-carboxyphenyl)hexafluoropropane, molar ratio 3:1, and 3g of N,N-dimethylformamide solution containing 0.1wt% sodium dodecyl sulfate were added. The mixture was sonicated at 40kHz, 50W / L, for 30min; nucleation stage: 25℃, 0.5h, 500rpm; growth stage: 60℃, 2h, 0.5MPa; ripening stage: cooling to 40℃ at 2℃ / min) and rapidly cooled to 25℃ under a nitrogen atmosphere (30kHz, 50W / L, 40℃, 30min, 0.3MPa) to obtain the composite nanofiller.

[0031] Resin matrix modification: 5g of epoxy resin prepolymer was compounded with 1g of trimethylolpropane triacrylate (mass ratio 5:1), and 0.5g of composite nanofiller (0.1 times the mass of epoxy resin prepolymer) was added. The mixture was ultrasonically dispersed (20kHz, 50W / L, 5min) and the viscosity of the system was controlled at 2000cps to obtain the modified resin matrix.

[0032] Functional additive compounding: Add 15g of phenolic curing agent, 0.5g of perfluorooctanoic acid, 1g of triphenyl phosphate, and 2g of photoinitiator complex (1g of benzophenone and 1g of thioxanthone, mass ratio 1:1) to 100g of modified resin matrix, and mix evenly to obtain a mixed system.

[0033] Directional curing molding: The mixture is ground to a fineness of ≤5μm and then subjected to gradient cooling under a magnetic field strength of 0.1T. First, it is cooled to 20℃ below the glass transition temperature at a rate of 2℃ / min, and then rapidly cooled to room temperature to form an anisotropic cross-linked network, thus obtaining nano-modified solder resist ink for SLP type substrates.

[0034] Example 2-18

[0035] Examples 2-18 follow the process flow and experimental methods of Example 1, but some parameters have been adjusted. The specific parameters are summarized in Table 1.

[0036] Table 1. Process parameters for Examples 1-18 (unit: g)

[0037]

[0038]

[0039] Comparative Examples 1-16

[0040] To verify the necessity of key components and process steps for the preparation of nano-modified solder resist ink for SLP-type substrates, comparative examples 1-16 were designed below to conduct experiments on the absence or substitution of key components and steps such as silane coupling agent modified nano-sized silica particles, copper-containing metal-organic framework seed crystals, and intercalation assembly treatment.

[0041] Comparative Example 1 differs from Example 1 in that it does not involve the construction of a nano-reinforcing phase. Instead, it directly uses epoxy resin prepolymer and trimethylolpropane triacrylate to prepare an unmodified resin matrix, and then prepares solder resist ink according to the subsequent steps of Example 1.

[0042] Comparative Example 2 differs from Example 1 in that it does not use nanoscale silica particles modified with silane coupling agent. Instead, it directly uses unmodified nanoscale silica particles (3g) and two-dimensional transition metal carbide sheets (1g) for intercalation assembly to prepare composite nanofillers. The remaining steps are the same as in Example 1.

[0043] Comparative Example 3 differs from Example 1 in that it does not use copper-containing metal-organic framework seed crystals. Instead, it uses silane coupling agent-modified nano-sized silica particles (3g) and two-dimensional transition metal carbide sheets (1g) for intercalation assembly in anhydrous ethanol. The remaining steps are the same as in Example 1.

[0044] Comparative Example 4 differs from Example 2 in that it does not undergo intercalation assembly. Instead, it uses a simple blend of silane coupling agent-modified nano-sized silica particles (4g), two-dimensional transition metal carbide sheets (1g), and copper-containing metal-organic framework seed crystals (0.15g) as a composite nanofiller. The remaining steps are the same as in Example 2.

[0045] Comparative Example 5 differs from Example 2 in that it does not undergo intercalation assembly or the addition of copper-containing metal-organic framework seed crystals. Instead, it simply blends nanoscale silica particles (4g) modified with silane coupling agent with two-dimensional transition metal carbide sheets (1g) as a composite nanofiller. The remaining steps are the same as in Example 2.

[0046] Comparative Example 6 differs from Example 5 in that it does not use silane coupling agent modified nanoscale silica particles and copper-containing metal-organic framework seed crystals, but only uses two-dimensional transition metal carbide sheets (1g) as nanofillers. The remaining steps are the same as in Example 5.

[0047] Comparative Example 7 differs from Example 5 in that it does not use two-dimensional transition metal carbide sheets. Instead, it uses silane coupling agent-modified nano-sized silica particles (4g) and copper-containing metal-organic framework seed crystals (0.15g) for intercalation assembly. The remaining steps are the same as in Example 5.

[0048] Comparative Example 8 differs from Example 8 in that it does not undergo ultrasonic dispersion treatment. Instead, it directly mixes epoxy resin prepolymer (6g), trimethylolpropane triacrylate (1g), and composite nanofiller (1.2g) before proceeding with subsequent steps. The remaining steps are the same as in Example 8.

[0049] Comparative Example 9 differs from Example 8 in that it does not use trimethylolpropane triacrylate, but only uses epoxy resin prepolymer (6g) and composite nanofiller (1.2g) for ultrasonic dispersion, with the remaining steps being the same as in Example 8.

[0050] Comparative Example 10 differs from Example 11 in that it does not use a phenolic curing agent. Instead, it adds 1.25g of perfluorooctanoic acid, 2g of triphenyl phosphate, and 3g of photoinitiator complex (2g of benzophenone and 1g of thioxanthone) to 100g of modified resin matrix. The remaining steps are the same as in Example 11.

[0051] Comparative Example 11 differs from Example 11 in that it does not use perfluorooctanoic acid. Instead, it adds 20g of phenolic curing agent, 2g of triphenyl phosphate, and 3g of photoinitiator complex (2g of benzophenone and 1g of thioxanthone) to 100g of modified resin matrix. The remaining steps are the same as in Example 11.

[0052] Comparative Example 12 differs from Example 11 in that it does not use triphenyl phosphate. Instead, it adds 20g of phenolic curing agent, 1.25g of perfluorooctanoic acid, and 3g of photoinitiator complex (2g of benzophenone and 1g of thioxanthone) to 100g of modified resin matrix. The remaining steps are the same as in Example 11.

[0053] Comparative Example 13 differs from Example 11 in that it does not use a photoinitiator complex. Instead, 20g of phenolic curing agent, 1.25g of perfluorooctanoic acid, and 2g of triphenyl phosphate are added to 100g of modified resin matrix. The remaining steps are the same as in Example 11.

[0054] Comparative Example 14 differs from Example 15 in that it does not undergo directional curing. Instead, the mixture is ground to a fineness of ≤5μm and then allowed to cure naturally at room temperature. The remaining steps are the same as in Example 15.

[0055] Comparative Example 15 differs from Example 15 in that it does not undergo gradient cooling. Instead, the mixture is ground to a fineness of ≤5μm and then directly cooled to room temperature at a magnetic field strength of 0.5T at a rate of 5℃ / min. The remaining steps are the same as in Example 15.

[0056] Comparative Example 16 differs from Example 15 in that no magnetic field is applied, and the mixture is directly ground to a fineness of ≤5μm, then cooled to 30°C below the glass transition temperature at a rate of 2°C / min, and then rapidly cooled to room temperature. The remaining steps are the same as in Example 15.

[0057] Table 2 Comparative Examples 1-16 Process Parameters (Unit: g)

[0058]

[0059]

[0060] To verify the performance of the nano-modified solder resist inks for SLP-type substrates prepared in Examples 1-18 and Comparative Examples 1-16, the following test methods were designed to evaluate adhesion, heat resistance, chemical resistance, and development resolution. The tests were based on the SLP-type substrate process flow to ensure the suitability of the inks for practical applications.

[0061] Adhesion test

[0062] Method: The prepared solder resist ink was printed onto an SLP-type substrate (the copper surface was ultra-roughened to a surface roughness Ra of 0.5-1.0 μm), followed by pre-baking (80℃, 20 min) and exposure (365 nm, 100 mJ / cm). 2 After development (1wt% Na2CO3 solution, 30s) and post-baking (150℃, 60min), test samples were prepared. The cross-cut adhesion test (ASTM D3359) was used. A 10×10 grid of 1mm×1mm squares was drawn on the sample surface, and 3M 600 tape was applied and then quickly peeled off at a 90-degree angle. The degree of square removal was observed and rated from 0B (complete removal) to 5B (no removal). Objective: To evaluate the adhesion performance of ink on SLP-type substrates, especially on ultra-roughened copper surfaces.

[0063] Heat resistance test

[0064] Methods: The prepared solder resist ink samples (using the same preparation procedure as the adhesion test) were placed in a 260℃ reflow oven to simulate the thermal shock conditions of the post-processing (selective electroplating of soft gold) of SLP-type substrates for 10 seconds, repeated 3 times. The appearance of cracks, blistering, or discoloration on the sample surface was observed, and the crack length (μm) was measured using an optical microscope (100x magnification). Shorter crack lengths indicated better heat resistance. Objective: To verify the stability and durability of the ink in high-temperature processes.

[0065] Chemical resistance test

[0066] Methods: The prepared solder resist ink samples were immersed in a sulfuric acid solution (pH 3.5, simulating a micro-etching environment) at 25°C for 48 hours. After removal, they were rinsed with deionized water, dried, and the surface corrosion was observed. Adhesion was tested (same as Method 1). The change in adhesion grade (ΔB, initial grade minus the grade after immersion) was recorded; a smaller ΔB indicates better chemical resistance. Objective: To evaluate the chemical stability of the ink in SLP-type substrate micro-etching and electroplating soft gold processes.

[0067] Development resolution test

[0068] Method: Solder resist ink was printed on an SLP substrate, and after pre-baking, it was exposed using a precision photomask (linewidth / spacing 50 / 50μm) (365nm, 100mJ / cm). 2 The ink was then developed in a 1 wt% Na₂CO₃ solution for 30 seconds. The edge sharpness of the developed pattern was observed using a scanning electron microscope (SEM), and the minimum resolvable linewidth (μm) was measured. A smaller linewidth indicates higher resolution. Objective: To verify the resolving power of the ink in a high-precision development process for SLP-type substrates.

[0069] Test Results

[0070] The solder resist inks prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the above tests. The adhesion, heat resistance crack length, chemical resistance adhesion changes and development resolution were recorded. The results are summarized in Table 3.

[0071] Table 3. Solder resist ink performance of Examples 1-3 and Comparative Examples 1-3

[0072] experimental group Adhesion (B) Heat resistance crack length (μm) Changes in chemical resistance adhesion (ΔB) Development resolution (μm) Example 1 5B 0 0 50 Example 2 5B 0 0 48 Example 3 5B 0 0 45 Comparative Example 1 3B 150 2 80 Comparative Example 2 4B 50 1 65 Comparative Example 3 4B 60 1 60

[0073] Analysis: Examples 1-3 all exhibited excellent adhesion (5B, no peeling), no cracking in heat resistance, no loss of adhesion in chemical resistance, and high developing resolution (45-50μm). This is attributed to the synergistic effect of the composite nanofiller (silane coupling agent modified nano-sized silica particles, two-dimensional transition metal carbide sheets, and copper-containing MOF seed crystals), which enhanced the crosslinking network and surface bonding of the ink. Comparative Example 1 lacked the nano-reinforcing phase, resulting in an incomplete crosslinking network, reduced adhesion (3B), poor heat resistance (150μm cracks), and a significant decrease in chemical resistance and developing resolution. Comparative Example 2 used unmodified silica particles, which reduced the number of surface active sites, affecting the interfacial bonding between the filler and the resin matrix, resulting in a slight decrease in performance. Comparative Example 3 lacked copper-containing MOF seed crystals, and the multi-level porous structure of the composite nanofiller was incomplete, reducing the chemical stability and developing accuracy of the ink.

[0074] The solder resist inks prepared in Examples 4-6 and Comparative Examples 4-5 were tested, with a focus on verifying the necessity of intercalation assembly treatment. The results are summarized in Table 4.

[0075] Table 4. Solder resist ink performance of Examples 4-6 and Comparative Examples 4-5

[0076] experimental group Adhesion (B) Heat resistance crack length (μm) Changes in chemical resistance adhesion (ΔB) Development resolution (μm) Example 4 5B 0 0 50 Example 5 5B 0 0 48 Example 6 5B 0 0 45 Comparative Example 4 4B 70 1 70 Comparative Example 5 3B 100 2 75

[0077] Analysis: Examples 4-6 maintained excellent performance. The intercalation assembly treatment ensured the uniform dispersion of the nanofiller and the formation of a multi-level porous structure, improving the mechanical and chemical stability of the ink. Comparative Example 4 lacked intercalation assembly and only underwent simple blending, leading to filler agglomeration, weakened interfacial bonding, and decreased performance. Comparative Example 5 lacked both intercalation assembly and copper-containing MOF seeds, further weakening the structural synergistic effect of the filler and significantly deteriorating its performance.

[0078] The solder resist inks prepared in Examples 7-9 and Comparative Examples 6-7 were tested to verify the effect of a single nanofiller component. The results are summarized in Table 5.

[0079] Table 5. Solder resist ink performance of Examples 7-9 and Comparative Examples 6-7

[0080] experimental group Adhesion (B) Heat resistance crack length (μm) Changes in chemical resistance adhesion (ΔB) Development resolution (μm) Example 7 5B 0 0 50 Example 8 5B 0 0 48 Example 9 5B 0 0 45 Comparative Example 6 3B 120 2 80 Comparative Example 7 4B 80 1 65

[0081] Analysis: Examples 7-9 maintained excellent overall performance through a complete formulation of composite nanofillers. Comparative Example 6 used only two-dimensional transition metal carbide sheets, lacking silica and MOF seeds, resulting in a single filler function and a significant decrease in heat resistance and chemical resistance. Comparative Example 7 lacked two-dimensional transition metal carbide sheets, weakening the filler's thermal conductivity and structural reinforcement effect; its performance was slightly better than Comparative Example 6 but still far inferior to the examples.

[0082] The solder resist inks prepared in Examples 10-12 and Comparative Examples 8-9 were tested to verify the effect of the resin matrix modification step. The results are summarized in Table 6.

[0083] Table 6. Solder resist ink performance of Examples 10-12 and Comparative Examples 8-9

[0084] experimental group Adhesion (B) Heat resistance crack length (μm) Changes in chemical resistance adhesion (ΔB) Development resolution (μm) Example 10 5B 0 0 50 Example 11 5B 0 0 48 Example 12 5B 0 0 45 Comparative Example 8 4B 60 1 65 Comparative Example 9 3B 90 2 70

[0085] Analysis: Examples 10-12, through the synergistic effect of ultrasonic dispersion and trimethylolpropane triacrylate, ensured the uniform distribution of fillers in the resin matrix and the integrity of the crosslinking network. Comparative Example 8, lacking ultrasonic dispersion, resulted in uneven filler distribution, reducing the mechanical properties and developing accuracy of the ink. Comparative Example 9, lacking trimethylolpropane triacrylate, exhibited reduced crosslinking density and significantly decreased heat and chemical resistance.

[0086] The solder resist inks prepared in Examples 13-15 and Comparative Examples 10-13 were tested to verify the effect of the compounding of functional additives. The results are summarized in Table 7.

[0087] Table 7. Solder resist ink performance of Examples 13-15 and Comparative Examples 10-13

[0088] experimental group Adhesion (B) Heat resistance crack length (μm) Changes in chemical resistance adhesion (ΔB) Development resolution (μm) Example 13 5B 0 0 50 Example 14 5B 0 0 48 Example 15 5B 0 0 45 Comparative Example 10 3B 100 2 75 Comparative Example 11 4B 50 1 65 Comparative Example 12 4B 60 1 60 Comparative Example 13 3B 80 2 70

[0089] Analysis: Examples 13-15 optimized the curing efficiency and surface properties of the ink through the synergistic effect of functional additives (phenolic curing agent, perfluorooctanoic acid, triphenyl phosphate, and photoinitiator complex). Comparative Examples 10-13, lacking phenolic curing agent, perfluorooctanoic acid, triphenyl phosphate, and photoinitiator complex respectively, resulted in incomplete crosslinking, surface tension imbalance, or reduced photocuring efficiency, leading to a significant decrease in overall performance.

[0090] The solder resist inks prepared in Examples 16-18 and Comparative Examples 14-16 were tested to verify the effect of directional curing. The results are summarized in Table 8.

[0091] Table 8. Solder resist ink performance of Examples 16-18 and Comparative Examples 14-16

[0092] experimental group Adhesion (B) Heat resistance crack length (μm) Changes in chemical resistance adhesion (ΔB) Development resolution (μm) Example 16 5B 0 0 50 Example 17 5B 0 0 48 Example 18 5B 0 0 45 Comparative Example 14 3B 120 2 80 Comparative Example 15 4B 70 1 65 Comparative Example 16 4B 80 1 60

[0093] Analysis: Examples 16-18, through magnetic field-assisted gradient cooling curing, formed an anisotropic cross-linked network, significantly improving the mechanical strength and chemical stability of the ink. Comparative Example 14 lacked directional curing, resulting in a disordered cross-linked network and a comprehensive decline in performance. Comparative Examples 15 and 16, respectively, lacked gradient cooling and a magnetic field, resulting in insufficient network structure regularity, affecting heat resistance and developing accuracy.

[0094] The test results of Examples 1-18 and Comparative Examples 1-16 show that the composite nanofiller, consisting of silane coupling agent-modified nano-sized silica particles, copper-containing MOF seeds, and two-dimensional transition metal carbide sheets, forms a multi-level porous structure through intercalation assembly, significantly enhancing the ink's adhesion, heat resistance, and chemical resistance. The synergistic effect of ultrasonic dispersion and trimethylolpropane triacrylate optimizes filler dispersion and crosslinking density, improving the ink's overall performance. The formulation of functional additives ensures the ink's curing efficiency and surface properties; the absence of any additive leads to performance degradation. The magnetic field-assisted and gradient cooling process for directional curing is crucial for forming an anisotropic crosslinked network, significantly improving the ink's mechanical and chemical stability. The development resolution (45-50 μm) of Examples 1-18 meets the high-precision development requirements of SLP-type substrates and is superior to that of the comparative examples (60-80 μm), indicating that the ink of this invention has significant advantages in high-precision circuit board manufacturing. Furthermore, taking the preferred embodiment 3 as an example, a transmission electron microscope (TEM) image of the composite nanofiller and a scanning electron microscope (SEM) image of the modified resin matrix are shown, and a physical image of the nano-modified solder resist ink is shown in handwritten form.

[0095] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the claims submitted herein.

Claims

1. A method for preparing nano-modified solder resist ink for SLP-type carriers, characterized in that: The process includes the following steps: (1) Nano-reinforced phase construction: Silane coupling agent modified nano-sized silica particles are mixed with two-dimensional transition metal carbide sheets at a mass ratio of (3-6):1 and copper-containing metal-organic framework seed crystals are added. Intercalation assembly is performed at 40-60℃ to form a composite nanofiller with a multi-level porous structure; (2) Resin matrix modification: Epoxy resin prepolymer and trimethylolpropane triacrylate are compounded at a mass ratio of (5-8):

1. 0.1-0.3 times the mass of epoxy resin prepolymer is added to the composite nanofiller obtained in step (1). Ultrasonic dispersion is used to control the viscosity of the system in the range of 2000-5000cps to obtain a modified resin matrix; (3) Functional additives are compounded. Preparation: By weight, for every 100 parts of modified resin matrix, add the following system: 15-25 parts of phenolic curing agent, 0.5-2 parts of fluorinated surfactant, 1-3 parts of phosphate ester adhesion promoter, and 2-5 parts of photoinitiator complex. The photoinitiator complex is a mixture of benzophenone and thioxanthone in a ratio of (1-3):1, and finally obtain a mixed system; (4) Directional curing molding: After grinding the mixed system to a fineness ≤5μm, perform gradient cooling treatment under a magnetic field strength of 0.1-0.5T. First, cool it at a rate of 2-5℃ / min to 20-30℃ below the glass transition temperature, and then quickly cool it to room temperature to form an anisotropic cross-linked network, and obtain nano-modified solder resist ink for SLP type carriers.

2. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: The preparation method of the silane coupling agent modified nano-sized silica particles in step (1) is as follows: γ-aminopropyltriethoxysilane and vinyltrimethoxysilane are mixed at a molar ratio of (0.5-2):1, and an ethanol solution containing 0.1-0.5 wt% sodium dodecylbenzenesulfonate is added at 5-10 times the mass of γ-aminopropyltriethoxysilane. A staged hydrolysis-condensation reaction is carried out under nitrogen protection: First stage: ultrasonic-assisted hydrolysis at 25-35℃, frequency 40kHz, power 50W / L, 3 0-60 min, second stage: microwave-assisted condensation at 50-60℃, frequency 50kHz, power 80W / L, pressure 0.5MPa, 2-4 h, to obtain the modified system; a mixture of silica and 2-hydroxy-4-acryloyloxybenzophenone in a mass ratio of 1:(2-6) is introduced into the modified system, wherein the mass of the mixture is 30-40% of the modified system, and a photoresponsive crosslinking network is formed by UV light initiation, wherein the wavelength of the UV light is 365nm and the intensity is 80mW / cm. 2 .

3. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: The CAS number of the two-dimensional transition metal carbide sheet in step (1) is 12363-89-2; the preparation method of the copper-containing metal-organic framework seed crystal in step (1) is as follows: copper chloride and 2,2'-bis(4-carboxyphenyl)hexafluoropropane are mixed at a molar ratio of (3-5):1, and N,N-dimethylformamide solution containing 0.1-0.5wt% sodium dodecyl sulfate is added at 1-3 times the mass of copper chloride. The reaction is carried out under nitrogen protection with ultrasonic assistance, wherein the ultrasonic frequency is 40kHz, the ultrasonic power is 50W / L, and the ultrasonic time is 30-60min; then a step-by-step temperature program is used for treatment. Nucleation stage: 25-35℃ is maintained for 0.5-1h and the stirring rate is 500rpm. Growth stage: the temperature is rapidly increased to 60-80℃ and maintained for 2-4h with a pressure of 0.5-1MPa. Maturation stage: the temperature is gradually decreased to 40-50℃ to complete the crystal orientation and obtain the copper-containing metal-organic framework seed crystal.

4. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: The intercalation assembly process in step (1) is as follows: Silane coupling agent modified nano-sized silica particles are mixed with two-dimensional transition metal carbide sheets and added to anhydrous ethanol at 15-20 times the mass of the two-dimensional transition metal carbide sheets. The mixture is pre-dispersed for 20-40 minutes using a high-speed homogenizer at 8000-12000 rpm to form a uniform suspension. Copper-containing metal-organic framework seed crystals are added to the suspension, wherein the mass of the copper-containing metal-organic framework seed crystals is 10-20% of the mass of the two-dimensional transition metal carbide sheets. The mixture is then transferred to a reaction vessel and treated under a nitrogen atmosphere: ultrasonic frequency 30kHz, ultrasonic power 50W / L, maintained at 40-50℃ for 30-60 minutes, pressure 0.3-0.5MPa, and rapidly cooled to 25-35℃ to obtain the product.

5. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: The CAS number of the epoxy resin prepolymer in step (2) is 1675-54-3; the CAS number of trimethylolpropane triacrylate in step (2) is 68987-79-1; the parameters of ultrasonic dispersion in step (2) are as follows: 20kHz, power 100-500W, time 5-30min.

6. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: The CAS number of the phenolic curing agent in step (3) is 9003-35-4.

7. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: In step (3), the phosphate ester adhesion promoter is triphenyl phosphate.

8. The method for preparing nano-modified solder resist ink for SLP-type carriers according to claim 1, characterized in that: The fluorinated surfactant in step (3) is perfluorooctanoic acid.

9. A nano-modified solder resist ink for SLP-type carrier boards, characterized in that, The nano-modified solder resist ink for SLP-type carriers is obtained by the preparation method described in any one of claims 1-8.

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