A processing method for solder resist dry film

Abstract

The present invention proposes a method for processing a solder resist dry film, the steps of which include: mixing a solder resist base component and a hardener according to a preset weight ratio to obtain a mixture; heating the mixture, detecting the refractive index of the mixture until it reaches a preset standard range, stopping heating and stirring, and degassing; uniformly coating the degassed mixture on a carrier film, drying in a vacuum environment, and obtaining a composite substrate; attaching an antistatically treated protective film to the surface of the composite substrate, pressing and shaping at room temperature, and obtaining a solder resist dry film. The uniformity and density of the solder resist film thickness during the packaging process are improved, and the isolation performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to a method for processing a solder resist dry film. Background Art

[0002] Solder mask plays a vital role in semiconductor packaging manufacturing and printed circuit board (PCB) production. With the development of technology, the form and application of solder mask are also evolving. Traditional solder mask usually refers to liquid solder mask, which is widely used in PCB manufacturing and semiconductor packaging. Solder mask covers the non-welding area of ​​the circuit board, isolates moisture, oxygen and other corrosive gases in the air, prevents metal lines from oxidation or corrosion, covers the unwelded area, prevents dust, particles and other pollutants from adhering to the surface of the circuit board, and ensures the cleanliness and normal function of the circuit board.

[0003] However, the liquid coating process in the related art easily leads to uneven film thickness, especially on complex or high-density circuit boards, which may cause film thickness fluctuations and affect product quality. In addition, defects such as bubbles, pinholes or shrinkage holes are easily generated during the liquid coating process, affecting the density and isolation performance of the film layer. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for processing a solder mask dry film, aiming to solve the problems of uneven film thickness and poor isolation performance of the solder mask layer during the packaging process.

[0005] To solve the above technical problems, the present invention is implemented as follows: a method for processing a solder mask dry film, the steps comprising:

[0006] S1, mixing the solder mask base component and the hardener according to a preset weight ratio to obtain a mixture;

[0007] S2, heating the mixture, detecting the refractive index of the mixture until it reaches within a preset standard range, stopping heating and stirring, and performing degassing;

[0008] S3, uniformly coating the degassed mixture on a carrier film, and drying it in a vacuum environment to obtain a composite substrate;

[0009] S4, laminating the protective film treated with antistatic treatment on the surface of the composite substrate, pressing and shaping at room temperature to obtain a solder resist dry film.

[0010] In some embodiments of the present invention, in step S1, the solder mask base component includes a resin matrix and a leveling gain component, the resin matrix includes at least one of bisphenol A epoxy resin, phenolic epoxy resin, and acrylic modified polyurethane resin, the leveling gain component includes at least one of siloxane modified polymer, fluorine-containing acrylate derivative, and polyether modified siloxane, and the hardener includes at least one of dicyandiamide, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride.

[0011] In some embodiments of the present invention, in step S1, the mass ratio of the resin matrix: the leveling enhancement component: the hardener is 100:0.1-10:5-50.

[0012] In some embodiments of the present invention, step S2 comprises:

[0013] S2.1, transfer the mixture to a reactor, initially heat it to 40-50°C, maintain it for 5-10 min, and then gradually increase it to 60-70°C;

[0014] S2.2, connecting the online sampling port to the reactor, allowing the mixture to pass through the refractive index detector during the circulation process, setting the detection frequency to 1 to 5 times / second, and automatically comparing it with the target refractive index after temperature compensation;

[0015] S2.3, obtaining the refractive index of the mixture and determining whether the refractive index is within a preset range;

[0016] S2.4: If yes, stop heating; if no, execute step S2.3.

[0017] In some embodiments of the present invention, between step S2.3 and step S2.4, the following is further included:

[0018] If yes, it is determined whether the holding time of the refractive index reaches a predetermined threshold; if not, step S2.3 is executed.

[0019] In some embodiments of the present invention, step S3 includes:

[0020] S3.1. Before coating, preheat the coating module to ensure the module temperature is stable, and calibrate the corresponding relationship between the slit width and the film thickness;

[0021] S3.2, convey the deaerated mixture to the coating module at a constant rate, and automatically adjust the slit width according to the feedback from the flow meter to ensure that the film thickness is maintained at the target value;

[0022] S3.3, first carry out a vacuum pre-baking stage at a temperature of 60-70°C and a pressure of 1.33-0.13 Pa, maintain for 5-10 minutes, then carry out a medium-temperature bubble suppression stage at a temperature of 80-100°C and a pressure of 0.13-0.013 Pa, maintain for 10-15 minutes, and finally carry out a cooling stabilization stage in which the temperature is lowered to room temperature and the pressure is raised to normal pressure, maintain for 5-10 minutes, to obtain a composite substrate.

[0023] In some embodiments of the present invention, step S4 includes:

[0024] S4.1. Introducing conductive materials or antistatic materials on the surface or inside of the film substrate to obtain a protective film;

[0025] S4.2. Ensure that the surfaces of the protective film and the composite substrate are clean and dry, accurately align the protective film and the composite substrate, and apply slight pressure through the primary pressing roller to make the protective film and the composite substrate initially contact;

[0026] S4.3, gradually increase the pressure, push the bubbles to the edge of the film layer by moving the pressing roller, and heat it at the same time to obtain a prefabricated film body;

[0027] S4.4, transfer the prefabricated film to a hot press, set the temperature to 30-80°C and the pressure to 5-50 bar, maintain for 1-5 minutes, then gradually return the temperature to room temperature, ensure uniform cooling and shaping of the film layer through airflow control or natural cooling, and obtain a solder mask dry film.

[0028] In some embodiments of the present invention, in step S4.1, the film substrate includes at least one of polyimide, polyethylene terephthalate, and polyamide, the conductive material includes at least one of carbon nanotubes, silver nanoparticles, and carbon black, and the antistatic material includes at least one of quaternary ammonium salt compounds, polyvinyl pyrrolidone, and polyvinyl alcohol.

[0029] Compared with the prior art, the processing method of the solder mask dry film in the present invention has the following beneficial effects:

[0030] The uniform distribution of the resin and hardener is ensured by precisely mixing the solder mask base components and the hardener in a preset weight ratio, laying the foundation for the uniformity of the film layer. Heating and real-time refractive index detection ensure that the mixture reaches the preset uniformity and reaction degree, avoiding uneven film thickness caused by component separation or incomplete reaction. The uniform coating of the mixture onto the carrier film in a vacuum environment, combined with precise coating equipment and vacuum drying, further ensures the consistency of the film thickness. Through primary lamination and gradual pressurization, the precise control of the lamination roller is combined with automatic adjustment of the slit width to maintain the film thickness within the target range. At the same time, precise control of the hot pressing and cooling process ensures that the film layer maintains a uniform thickness in the final shaping stage.

[0031] The film thickness of the solder mask dry film can be strictly controlled within a preset range to ensure that the film thickness of each batch of products is highly consistent and meets the needs of high-precision electronic manufacturing. Through precise coating and lamination processes, the solder mask dry film can achieve high-precision film layer distribution on complex and high-density circuit boards to meet the needs of fine circuits and high-density packaging. The highly uniform and dense film layer reduces electrical problems caused by film defects (such as bubbles and pinholes) and improves the overall circuit board yield and performance stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure is a schematic flow chart of a method for processing a solder resist dry film in one embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] Please refer to Figure 1 The present invention provides a method for processing a solder mask dry film, the steps comprising:

[0035] S1. Mix the solder mask base component and the hardener according to a preset weight ratio to obtain a mixture.

[0036] The solder mask base component includes a resin matrix and a leveling gain component, the resin matrix includes at least one of bisphenol A epoxy resin, phenolic epoxy resin, and acrylic modified polyurethane resin, the leveling gain component includes at least one of siloxane modified polymer, fluorine-containing acrylate derivative, and polyether modified siloxane, and the hardener includes at least one of dicyandiamide, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride.

[0037] The resin matrix provides excellent adhesion and high mechanical strength, ensuring the stability and durability of the solder mask dry film in subsequent processes. The hardener forms a three-dimensional network structure through a cross-linking reaction with the resin matrix, significantly improving the mechanical strength and heat resistance of the film. The leveling gain component reduces the surface tension, promotes the uniform spreading of the resin on the carrier film, reduces surface defects such as pinholes, bubbles and shrinkage holes, provides excellent self-leveling performance, and ensures high flatness and smooth surface of the film.

[0038] The combination of bisphenol A epoxy resin, phenolic epoxy resin and anhydride hardener significantly improves the heat resistance of the film layer, enabling it to maintain stable physical properties in a high temperature environment and not easily deformed or degraded.

[0039] The combination of acrylic modified polyurethane resin and polyisocyanate hardener provides higher chemical resistance and corrosion resistance, suitable for harsh working environments. Phenolic epoxy resin improves the stability of the film in a chemically corrosive environment due to its high crosslinking density and chemical resistance, preventing the film from degrading due to chemical corrosion. The hardener forms a strong network structure through crosslinking reaction with the resin matrix, further enhancing the chemical resistance and thermal stability of the film.

[0040] The combination of different resins and hardeners enables the solder mask dry film to adapt to different application environments and performance requirements, such as high-temperature electronic packaging, aerospace electronic components, etc. Excellent leveling and surface flatness meet the strict requirements of high-precision printed circuit boards (PCBs) and other precision electronic manufacturing processes.

[0041] According to the mass ratio, the resin matrix: leveling enhancement component: hardener = 100:0.1~10:5~50. For example, it can be 100:0.1:5, 100:1:10, 100:10:50, etc.

[0042] S2. Heat the mixture, detect the refractive index of the mixture until it reaches a preset standard range, stop heating and stirring, and perform degassing.

[0043] Through real-time monitoring of the refractive index, the uniform mixing of the resin matrix, leveling gain component and hardener in the mixture is ensured, and the consistency of the ratio of each batch of products is ensured. The viscosity and dispersibility of the mixture are controlled, the fluidity and uniformity of the mixture are improved, and the quality of the film layer after coating is ensured. Through effective degassing treatment, the content of bubbles and solvents in the film layer is reduced, the density and uniformity of the film layer are improved, and the film formation defects are reduced. The production process is automated and adjusted in real time, the accuracy and stability of process control are improved, and human errors are reduced. The heat resistance, chemical stability and mechanical strength of the solder mask dry film in high-demand application scenarios are ensured, and the overall reliability and market competitiveness of the product are improved.

[0044] Step S2 includes:

[0045] S2.1. Transfer the mixture to a reactor, initially heat it to 40-50°C, for example, 40°C, 45°C, 50°C, maintain it for 5-10 min, for example, 5 min, 8 min, 10 min, and then gradually increase it to 60-70°C, for example, 60°C, 65°C, 70°C.

[0046] By gradually raising the temperature of the mixture to 40-50°C, it helps the initial dissolution of the resin matrix and the hardener, ensuring that the components are fully mixed to form a uniform mixture. Keeping it at 40-50°C for 5-10 minutes promotes the initial chemical reaction and improves the uniformity and stability of the mixture. Gradually increase the temperature to 60-70°C to control the reaction rate, prevent violent reactions or excessive cross-linking caused by sudden temperature rise, and ensure a smooth reaction process.

[0047] Heating reduces the viscosity of the mixture and improves fluidity, facilitating subsequent processing and coating processes. It helps to evenly disperse the leveling gain component in the resin matrix, avoids excessive or low local concentration, and improves the overall uniformity of the mixture.

[0048] S2.2. Connect the online sampling port to the reactor, and allow the mixture to pass through the refractive index detector during the circulation process. The detection frequency is set to 1 to 5 times / second, and the temperature compensation is performed and then automatically compared with the target refractive index.

[0049] If the mixture is completely homogeneous, the refractive index of each area is consistent and equal to the overall refractive index. If there is component separation or aggregation in the mixture, the refractive index of different areas will be different, causing fluctuations or deviations in the overall measurement results. The refractive index is very sensitive to changes in the proportion of components in the mixture. Even a small change in the proportion of components will cause a significant change in the refractive index. This high sensitivity makes the refractive index an effective tool for evaluating the homogeneity of a mixture. Real-time monitoring and automatic comparison reduce dependence on operators, reduce human operating errors, and improve the stability and consistency of the production process.

[0050] S2.3. Obtain the refractive index of the mixture and determine whether the refractive index is within a preset range.

[0051] By judging whether the refractive index is within the preset range, we can confirm that the proportion of each component in the mixture meets the design requirements and ensure the performance and quality of the final product. We can timely detect the deviation of the mixture ratio and identify the problems that may occur during the mixing process, such as uneven components and incomplete reaction, to prevent unqualified mixtures from entering the subsequent process. By obtaining and judging the refractive index in real time, we can ensure that each batch of mixtures has reached the predetermined formula standard before entering the degassing and coating process, thus improving the consistency and reliability of the product.

[0052] S2.4: If yes, stop heating; if no, execute step S2.3.

[0053] Between step S2.3 and step S2.4, the method further includes:

[0054] If yes, it is determined whether the holding time of the refractive index reaches a predetermined threshold; if not, step S2.3 is executed.

[0055] It not only confirms that the refractive index is within the preset range, but also ensures that it remains stable for a certain period of time to avoid misjudgment due to instantaneous fluctuations or uneven mixing in a short period of time. Ensuring that the refractive index of the mixture is stable within the target range before stopping heating and stirring reflects the uniformity of the mixture and the adequacy of the reaction.

[0056] By setting the holding time threshold, we can avoid stopping heating too early due to the short-term refractive index reaching the target range, and ensure that the mixture has been fully reacted and evenly mixed. We can ensure that each batch of mixture has reached the ideal mixing state before entering the degassing process, reducing fluctuations and unstable factors in the production process. Through the dual confirmation of refractive index range judgment and holding time judgment, we can improve the strictness of quality control and ensure that product quality meets the highest standards. We can reduce defects caused by uneven mixing or insufficient reaction, and improve the yield rate and market competitiveness of the final product.

[0057] The obtained mixture is subjected to viscosity measurement to determine whether the viscosity curve change is <1%. If so, proceed to step S3.

[0058] S3, coating the deaerated mixture evenly on a carrier film, and drying it in a vacuum environment to obtain a composite substrate.

[0059] Step S3: By evenly coating the deaerated mixture onto the carrier film and drying it in a vacuum environment, the following key technical effects are achieved: ensuring that the thickness of each layer of film meets the design specifications and improving product consistency. Effectively remove bubbles and solvent residues, reduce defects in the film layer, and improve the quality of the film layer. Improve the durability and stability of the film layer through efficient cross-linking and optimized adhesion. Improve the efficiency and stability of the production line through vacuum drying and optimization of process parameters, provide high-quality composite substrates, and ensure the smooth lamination and pressing of subsequent protective films. Produce high-performance, high-reliability solder mask dry films to meet the high-standard market requirements and enhance the market competitiveness of products.

[0060] Step S3 includes:

[0061] S3.1. Before coating, preheat the coating module to ensure that the module temperature is stable, and calibrate the corresponding relationship between the slit width and the film thickness.

[0062] By preheating the coating module before coating, ensure that the internal temperature of the module reaches and maintains the set value. This helps the mixture maintain uniform fluidity during the coating process and avoids uneven film thickness caused by module temperature fluctuations. Stable module temperature reduces thermal stress in the film during coating and initial curing, prevents warping or deformation of the film, and improves the flatness and consistency of the product. By calibrating the correspondence between the slit width and the film thickness, ensure that the film thickness can be accurately adjusted according to actual needs during the coating process. This is crucial to achieving a predetermined film thickness (such as 25µm ±1µm). The calibration process ensures that the coating module can maintain consistent film thickness under different operating conditions (such as changes in mixture viscosity), reduces fluctuations in film thickness, and improves product uniformity and quality.

[0063] S3.2. The degassed mixture is delivered to the coating module at a constant rate. The slit width is automatically adjusted according to the feedback from the flow meter to ensure that the film thickness is maintained at the target value.

[0064] By delivering the deaerated mixture to the coating module at a constant rate, the amount of mixture coated per unit time is ensured to be stable, thereby achieving precise control of film thickness. According to the real-time feedback of the flow meter, the slit width of the coating module is automatically adjusted to ensure that the film thickness is always maintained at the target value (such as 25µm ±1µm). This closed-loop control system greatly improves the accuracy and consistency of film thickness control. The real-time flow rate data provided by the flow meter enables the system to respond instantly to changes in the mixture flow rate, and maintains film thickness stability by automatically adjusting the slit width, reducing human intervention and operating errors. The automated flow control system can effectively cope with flow fluctuations or changes in mixture viscosity that may occur during the production process, maintain film thickness consistency, and improve product uniformity and quality.

[0065] S3.3, first carry out a vacuum pre-baking stage at a temperature of 60-70°C and a pressure of 1.33-0.13 Pa, maintain for 5-10 minutes, then carry out a medium-temperature bubble suppression stage at a temperature of 80-100°C and a pressure of 0.13-0.013 Pa, maintain for 10-15 minutes, and finally carry out a cooling stabilization stage in which the temperature is lowered to room temperature and the pressure is raised to normal pressure, maintain for 5-10 minutes, to obtain a composite substrate.

[0066] Under low temperature and medium vacuum conditions, the solvent and some volatile components in the mixture are initially volatilized to reduce the residual solvent in the film layer. The low pressure environment under vacuum conditions is used to promote the rise and discharge of fine bubbles in the mixture, reduce the formation of bubbles in the film layer, and improve the density and uniformity of the film layer.

[0067] Under higher temperature and lower pressure, the volatilization of residual solvent is accelerated to ensure that the solvent is completely discharged, and the film layer is prevented from warping or cracking due to residual solvent during the curing process. Under higher temperature and lower pressure conditions, residual bubbles are further eliminated to ensure the flatness and density of the film layer.

[0068] By gradually lowering the temperature, the film layer is cooled evenly to prevent stress concentration and film deformation caused by sudden temperature changes. Slowly returning to normal pressure prevents film warping or cracking caused by rapid pressure changes, ensuring the flatness and stability of the composite substrate.

[0069] Through multi-stage vacuum drying, a tightly cross-linked resin network structure is formed, the mechanical strength and wear resistance of the film layer are improved, and the durability and reliability of the solder mask dry film are enhanced. Solvents and bubbles are effectively removed, defects in the film layer are reduced, the high quality and flatness of the film layer are ensured, and the performance and consistency of the final product are improved. Through the staged drying process, solvent volatilization and bubble discharge are optimized, drying time and energy consumption are reduced, and production efficiency is improved. The temperature and pressure parameters of each stage are precisely controlled to ensure that the drying effect of each stage meets the expectations and improve the controllability and stability of the process.

[0070] S4. A protective film treated with antistatic agent is attached to the surface of the composite substrate, pressed and fixed at room temperature to obtain a solder resist dry film.

[0071] Step S4 includes:

[0072] S4.1. Introducing a conductive material or an antistatic material on the surface or inside of a film substrate to obtain a protective film. The film substrate includes at least one of polyimide, polyethylene terephthalate, and polyamide, the conductive material includes at least one of carbon nanotubes, silver nanoparticles, and carbon black, and the antistatic material includes at least one of quaternary ammonium salt compounds, polyvinyl pyrrolidone, and polyvinyl alcohol.

[0073] The introduction of conductive materials makes the protective film have excellent conductivity, effectively disperses and releases static electricity, and prevents static electricity accumulation and discharge from damaging electronic components. The addition of antistatic materials further reduces the surface resistance of the film layer, improves the antistatic performance, and ensures the stability of the solder mask dry film in high-precision electronic packaging.

[0074] The film matrix material provides excellent mechanical strength and toughness, making the solder mask dry film not easy to break or deform during use, improving the durability of the product. Highly heat-resistant materials such as polyimide and polyethylene terephthalate ensure that the solder mask dry film maintains stable physical and chemical properties in high temperature environments and is not easy to degrade or deteriorate.

[0075] The synergistic effect of the leveling gain component (mixed in the previous step) and the conductive and antistatic materials improves the fluidity and spreadability of the mixture, ensures uniform spreading and high flatness of the film layer, and reduces film defects such as bubbles and pinholes. The conductive and antistatic materials are evenly dispersed in the film matrix to avoid material aggregation or stratification, ensuring the overall uniformity and consistency of the film layer.

[0076] S4.2. Ensure that the surfaces of the protective film and the composite substrate are clean and dry, accurately align the protective film and the composite substrate, and apply slight pressure through the primary lamination roller to make initial contact between the protective film and the composite substrate.

[0077] Ensure that there is no dust, oil or other contaminants on the surface of the protective film and the composite substrate, improve the bonding quality between the two layers of materials, and prevent the film from falling off or causing defects. Keep the surface dry to avoid moisture or solvent residue that affects the bonding effect and ensure a firm bond between the film layers.

[0078] Through the precise alignment system, the protective film and the composite substrate are perfectly connected to avoid edge misalignment or incomplete coverage, and the uniformity and consistency of the overall film layer are improved. The primary lamination roller applies slight pressure to make the protective film and the composite substrate initially contact, promote the close combination of the two layers of materials, and reduce the formation of bubbles and wrinkles. The slight pressure helps to initially expel bubbles in the film layer and improve the flatness and quality of the film layer.

[0079] The use of automated primary lamination rollers enables fast and efficient lamination of the protective film and the composite substrate, improving the overall efficiency of the production line. The automatic alignment and lamination system reduces operator intervention, reduces human errors, and improves the stability and consistency of the production process.

[0080] S4.3. Gradually increase the pressure, move the pressing roller, push the bubbles to the edge of the film layer, and heat it at the same time to obtain a prefabricated film body.

[0081] By gradually increasing the pressure, the entire film layer is evenly compressed, avoiding local overpressure or underpressure, and improving the overall flatness and consistency of the film layer. As the lamination roller moves, the bubbles are gradually pushed to the edge of the film layer and discharged, reducing the number of bubbles inside the film layer, improving the density and surface quality of the film layer. Heating during the lamination process promotes the activation or softening of the adhesive, enhances the adhesion between the protective film and the composite substrate, and ensures a firm bond between the film layer. Appropriate temperature increase helps accelerate the cross-linking reaction between the resin matrix and the hardener, forming a strong three-dimensional network structure, and improving the mechanical strength and durability of the film layer.

[0082] S4.4. Transfer the prefabricated film to a hot press, set the temperature to 30-80°C and the pressure to 5-50 bar, maintain for 1-5 minutes, then gradually return the temperature to room temperature, and ensure uniform cooling and shaping of the film layer through airflow control or natural cooling to obtain a solder resist dry film.

[0083] By applying high temperature and high pressure in the hot press, the adhesion between the protective film and the composite substrate is further enhanced to ensure the firm bonding of the film layer. The temperature is set at 30~80℃ to promote the cross-linking reaction between the resin matrix and the hardener, forming a more solid three-dimensional network structure, and improving the mechanical strength and heat resistance of the film layer.

[0084] By gradually lowering the temperature, the film layer is cooled evenly to prevent stress concentration and warping or cracking of the film layer caused by sudden temperature changes. Airflow control or natural cooling is used to ensure that the temperature of the film layer drops evenly during the entire cooling process to maintain the flatness and consistency of the film layer. By controlling the cooling rate, the film layer is ensured to achieve the final physical form and mechanical properties during the shaping process, thereby improving the stability and reliability of the product.

[0085] The final solder mask dry film is inspected for defects such as pits, bubbles, and cracks, so that the film appearance defect rate of the obtained solder mask dry film is less than 0.1%, and the film appearance defect rate = defect area / overall area.

[0086] The specific structures of all mechanical equipment used in the processing method of the present invention, such as sampling probe, viscometer, reactor, coating module, etc., are known to those skilled in the art and will not be described in detail here.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing a solder mask dry film, characterized in that the steps include: S1, mixing the solder mask base component and the hardener according to a preset weight ratio to obtain a mixture; S2, heating the mixture, detecting the refractive index of the mixture until it reaches within a preset standard range, stopping heating and stirring, and performing degassing; S3, uniformly coating the degassed mixture on a carrier film, and drying it in a vacuum environment to obtain a composite substrate; Step S3 includes: S3.

1. Before coating, preheat the coating module to ensure the module temperature is stable, and calibrate the corresponding relationship between the slit width and the film thickness; S3.2, convey the deaerated mixture to the coating module at a constant rate, and automatically adjust the slit width according to the feedback from the flow meter to ensure that the film thickness is maintained at the target value; S3.3, firstly carry out a vacuum pre-baking stage at a temperature of 60-70°C and a pressure of 1.33-0.13 Pa, maintaining for 5-10 minutes, then carry out a medium-temperature bubble suppression stage at a temperature of 80-100°C and a pressure of 0.13-0.013 Pa, maintaining for 10-15 minutes, and finally carry out a cooling stabilization stage in which the temperature is lowered to room temperature and the pressure is raised to normal pressure, maintaining for 5-10 minutes, to obtain a composite substrate; S4, laminating the protective film treated with antistatic treatment on the surface of the composite substrate, pressing and shaping at room temperature to obtain a solder resist dry film.

2. The method for processing a solder mask dry film according to claim 1, characterized in that: In step S1, the solder mask base component includes a resin matrix and a leveling gain component, the resin matrix includes at least one of bisphenol A epoxy resin, phenolic epoxy resin, and acrylic modified polyurethane resin, the leveling gain component includes at least one of siloxane modified polymer, fluorine-containing acrylate derivative, and polyether modified siloxane, and the hardener includes at least one of dicyandiamide, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride.

3. The method for processing a solder mask dry film according to claim 2, characterized in that: In step S1, the mass ratio of the resin matrix: the leveling enhancement component: the hardener is 100:0.1-10:5-50.

4. The method for processing a solder mask dry film according to claim 1, characterized in that: Step S2 includes: S2.1, transfer the mixture to a reactor, initially heat it to 40-50°C, maintain it for 5-10 min, and then gradually increase it to 60-70°C; S2.2, connecting the online sampling port to the reactor, allowing the mixture to pass through the refractive index detector during the circulation process, setting the detection frequency to 1 to 5 times / second, and automatically comparing it with the target refractive index after temperature compensation; S2.3, obtaining the refractive index of the mixture and determining whether the refractive index is within a preset range; S2.4: If yes, stop heating; if no, execute step S2.

3.

5. The method for processing a solder mask dry film according to claim 4, characterized in that: Between step S2.3 and step S2.4, the method further includes: If yes, it is determined whether the holding time of the refractive index reaches a predetermined threshold; if not, step S2.3 is executed.

6. The method for processing a solder mask dry film according to claim 1, characterized in that: Step S4 includes: S4.

1. Introducing conductive materials or antistatic materials on the surface or inside of the film substrate to obtain a protective film; S4.

2. Ensure that the surfaces of the protective film and the composite substrate are clean and dry, accurately align the protective film and the composite substrate, and apply slight pressure through the primary pressing roller to make the protective film and the composite substrate initially contact; S4.3, gradually increase the pressure, push the bubbles to the edge of the film layer by moving the pressing roller, and heat it at the same time to obtain a prefabricated film body; S4.4, transfer the prefabricated film to a hot press, set the temperature to 30-80°C and the pressure to 5-50 bar, maintain for 1-5 minutes, then gradually return the temperature to room temperature, ensure uniform cooling and shaping of the film layer through airflow control or natural cooling, and obtain a solder mask dry film.

7. The method for processing a solder mask dry film according to claim 6, characterized in that: In step S4.1, the film substrate includes at least one of polyimide, polyethylene terephthalate, and polyamide, the conductive material includes at least one of carbon nanotubes, silver nanoparticles, and carbon black, and the antistatic material includes at least one of quaternary ammonium salt compounds, polyvinyl pyrrolidone, and polyvinyl alcohol.

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