A screen pasting process of screen pasting UV inkjet printing glue

Abstract

This invention relates to the field of semiconductor chip packaging and bonding technology, and discloses a screen bonding process using UV inkjet printing adhesive, comprising the following steps: inkjet printing, using a photothermal dual-curing UV inkjet printing adhesive, the adhesive is precisely coated onto the surface of the screen or glass to be bonded using an inkjet printing device, with optional UV irradiation, depending on the material of the product to be bonded and the bonding requirements, the coated adhesive is either cured by UV irradiation or not. During screen bonding, the adhesive is precisely and uniformly coated onto the surface to be bonded by using an inkjet printing device and a compatible UV inkjet printing adhesive, which can solve the problems of excessive time spent on adhesive coating in traditional scraping processes, which restricts production cycle, and excessive adhesive coating thickness leading to serious material waste, poor uniformity, and easy generation of bubbles, ensuring the high efficiency and economy of screen bonding production, improving material utilization and bonding quality.

Description

Technical Field

[0001] This invention relates to the field of semiconductor chip packaging and bonding technology, specifically to a screen bonding process for UV inkjet printing adhesive. Background Technology

[0002] In screen bonding processes, the adhesive is typically applied using a scraping method.

[0003] Currently, due to the inherent limitations of the adhesive application process, the adhesive application time during screen bonding can be as long as 40 seconds, severely restricting overall production efficiency. Furthermore, the adhesive coating thickness needs to be controlled within 250-350um, resulting in large adhesive consumption and significant waste. Poor thickness uniformity also easily leads to air bubbles during bonding, affecting the bonding tightness. In addition, the traditional process requires UV curing immediately after adhesive application before subsequent bonding can proceed, making it impossible to flexibly adjust the process according to product materials and requirements. Moreover, for well-cured products, the secondary heat curing time is fixed at 2 hours, further increasing production time and affecting production cycle and cost control.

[0004] Therefore, a screen bonding process for UV inkjet printing adhesive is proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a screen bonding process for UV inkjet printing adhesive, which solves the problem mentioned in the background art of air bubbles easily generated during the bonding process due to poor thickness uniformity.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a screen bonding process for UV inkjet printing adhesive, comprising the following steps: Step 1: Inkjet printing. A UV inkjet printing adhesive with photothermal dual curing is used. The adhesive is precisely applied to the surface of the screen or glass to be bonded using an inkjet printing device. The inkjet printing time is controlled at 10-15 seconds, and the coating thickness of the adhesive is controlled at 20-30μm. Step 2: Optional UV irradiation. Depending on the material of the product to be bonded and the bonding requirements, choose to cure the coated adhesive with UV light or not. When using UV light, select UV light with a wavelength of 365nm or 395nm. Step 3: Glass bonding. The parts to be bonded, coated with UV inkjet printing adhesive, are precisely aligned and bonded to the corresponding glass. Step 4: Vacuum treatment. Place the bonded components into a vacuum device for vacuum treatment to remove any residual air bubbles between the bonding surfaces. Step 5: Initial heat curing. Place the vacuum-treated components in a constant temperature environment of 80-90℃ for 30 minutes to complete the initial heat curing of the adhesive. Step Six: Quality Inspection. Conduct a quality inspection on the bonded components after the initial heat curing, and classify the components into good and defective products based on the inspection results. Step 7: Secondary heat curing of good products. Place the qualified good components in a constant temperature environment of 80℃ for 1-2 hours to complete the secondary heat curing of the adhesive. Step 8: Repair of defective products. For defective components that fail the inspection, repair them by removing the original adhesive and defective parts from their surfaces, and then re-bonding them according to the process flow from Step 1 to Step 7. The viscosity range of the UV inkjet printing adhesive is 10-25 cps.

[0007] Preferably, in step one, the photocuring mechanism of the photothermal dual-curing UV inkjet printing adhesive is to initiate curing by ultraviolet light irradiation, wherein the wavelength of the ultraviolet light is 365nm or 395nm, and the thermal curing condition of the photothermal dual-curing UV inkjet printing adhesive is to maintain a temperature of 80-90℃, wherein the maintenance time is selected as 20 minutes, 2 hours or 3 hours according to the process requirements.

[0008] Preferably, in step one, the inkjet printing equipment is a precision CNC inkjet printing system, the system presets the coating pattern and thickness through software, the component to be bonded is a screen or a glass substrate, and the adhesive is coated on the surface of the screen or the surface of the glass substrate.

[0009] Preferably, in step two, the conditions for selecting UV irradiation include: the product to be bonded is a material with high UV transmittance, the adhesive needs to have preliminary positioning ability before bonding, and the production cycle requires rapid pre-curing. The conditions for choosing not to perform UV irradiation include: the parts to be bonded contain materials sensitive to ultraviolet light, the adhesive needs to maintain its fluidity until vacuum processing to facilitate the removal of air bubbles, and the process route is to be simplified as much as possible.

[0010] Preferably, in step three, the precise alignment and bonding is completed by a high-precision visual alignment system, with the alignment accuracy controlled within ±5μm. The component to be bonded and the glass are contacted and pressed together by a robotic arm or a precision platform, with the initial pressing force controlled between 0.05-0.2MPa.

[0011] Preferably, in step four, the vacuum treatment is carried out in a vacuum chamber, the vacuum degree of the vacuum chamber is evacuated to below 10 Pa, and the pressure holding time is 30-120 seconds. During the vacuum treatment, the component is placed on a heatable platform, and the platform temperature is maintained at 25-40°C to maintain the appropriate fluidity of the adhesive.

[0012] Preferably, in step five, the initial heat curing is carried out in a circulating hot air oven or tunnel oven with a temperature control accuracy of ±1℃. During the initial heat curing process, the components are placed flat on a tray with a gap of more than 10mm between the components to ensure uniform hot air circulation.

[0013] Preferably, in step six, the quality inspection includes automated optical inspection and manual sampling. The automated optical inspection uses a machine vision system to detect appearance defects of the components, including bubbles, foreign objects, scratches, and bonding misalignment. The bubble detection sensitivity is for bubbles with a diameter greater than 50 μm, and the misalignment detection accuracy is ±10 μm. The manual sampling inspection samples the components that have passed the automated inspection and checks the bonding interface and preliminary bonding strength using a high-magnification microscope and a shear force tester. The sampling ratio is 5%.

[0014] Preferably, in step seven, the secondary heat curing of the good product is carried out in a batch oven. The oven is equipped with a forced convection system to ensure temperature uniformity, which is ±2℃. The duration of the secondary heat curing is selected according to the reliability level requirements of the final product. The correspondence between the reliability level requirements and the heat preservation time is as follows: 1 hour for commercial grade products, 1.5 hours for industrial grade products, and 2 hours for automotive grade or high reliability products.

[0015] Preferably, in step eight, the defective product rework specifically includes the following sub-steps: placing the defective component on a heatable rework platform and heating it to 80-100℃ to soften the adhesive layer; carefully separating the screen and glass from the edge of the component using a precision scraper or suction tool; wiping the residual adhesive surface with a lint-free cloth soaked in a special organic solvent until the adhesive layer is completely removed and the surface is smooth; then using a plasma cleaner to activate the cleaned screen and glass surface, with a processing power of 300-500W and a processing time of 30-60 seconds; after completing the surface treatment, the screen and glass, as the parts to be bonded, re-enter the inkjet printing process in step one.

[0016] Compared with the prior art, the present invention provides a screen bonding process for UV inkjet printing adhesive, which has the following advantages: 1. In this invention, during screen bonding, an inkjet printing device and a compatible UV inkjet printing adhesive are used to apply the adhesive precisely and evenly to the surface to be bonded. This solves the problems of excessively long application time in traditional scraping adhesive processes, which restricts production cycle, and excessive adhesive coating thickness leading to serious material waste, poor uniformity, and easy generation of air bubbles. This ensures the high efficiency and economy of screen bonding production, and improves material utilization and bonding quality.

[0017] 2. In this invention, when performing screen bonding, a UV inkjet printing adhesive with photothermal dual curing is used, and optional UV irradiation steps and flexibly adjustable thermosetting parameters are set in the process flow. This allows for the autonomous selection of whether to perform UV pre-curing and to match different thermosetting conditions according to the specific material of the product to be bonded and the bonding requirements. This solves the problem of fixed curing processes and inflexible adjustments in traditional processes, enabling the screen bonding process to adapt to a wider range of product types and production requirements, and improving the flexibility and applicability of the process.

[0018] 3. In this invention, when bonding the screen, a vacuum process is introduced after the glass is bonded to remove interface bubbles. A complete follow-up process including initial heat curing, quality inspection, secondary heat curing of good products, and rework of defective products is set up. This can systematically solve the problems of loose bonding, unstable yield, ineffective reuse of defective products, and time-consuming secondary curing caused by uneven adhesive layer and insufficient curing in traditional processes. This ensures the reliability, stability, and final yield of the bonded components and optimizes production resources and efficiency. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: The screen bonding process of this UV inkjet printing adhesive includes the following steps: Step 1: Inkjet printing. A UV inkjet printing adhesive with photothermal dual curing is used. The adhesive is precisely applied to the screen to be bonded using an inkjet printing device. The inkjet printing time is controlled within 10 seconds, and the coating thickness of the adhesive is controlled within 20μm. Step 2: Optional UV irradiation. Depending on the material of the product to be bonded and the bonding requirements, select UV irradiation to cure the coated adhesive. When using UV irradiation, select UV light with a wavelength of 365nm. Step 3: Glass bonding. The parts to be bonded, coated with UV inkjet printing adhesive, are precisely aligned and bonded to the corresponding glass. Step 4: Vacuum treatment. Place the bonded components into a vacuum device for vacuum treatment to remove any residual air bubbles between the bonding surfaces. Step 5: Initial heat curing. Place the vacuum-treated components in a constant temperature environment of 80℃ for 30 minutes to complete the initial heat curing of the adhesive. Step Six: Quality Inspection. Conduct a quality inspection on the bonded components after the initial heat curing, and classify the components into good and defective products based on the inspection results. Step 7: Secondary heat curing of good products. Place the qualified good components in a constant temperature environment of 80℃ for 1 hour to complete the secondary heat curing of the adhesive. Step 8: Repair of defective products. For defective components that fail the inspection, repair them by removing the original adhesive and defective parts from their surfaces, and then re-bonding them according to the process flow from Step 1 to Step 7. The viscosity range of the UV inkjet printing adhesive is 10 cps.

[0021] In step one, the photocuring mechanism of the photothermal dual-curing UV inkjet printing adhesive is to initiate curing by ultraviolet light irradiation with a wavelength of 365nm. The thermal curing conditions of the photothermal dual-curing UV inkjet printing adhesive are to maintain a temperature of 80℃ for 20 minutes, depending on the process requirements.

[0022] In step one, the inkjet printing equipment is a precision CNC inkjet printing system. The system presets the coating pattern and thickness through software. The part to be bonded is a screen, and the adhesive is coated on the surface of the screen.

[0023] In step two, the conditions for selecting UV irradiation include: the product to be laminated is a material with high UV transmittance, the adhesive needs to have preliminary positioning ability before lamination, and the production cycle requires rapid pre-curing. The conditions for choosing not to perform UV irradiation include: the parts to be bonded contain materials sensitive to ultraviolet light, the adhesive needs to maintain its fluidity until vacuum processing to facilitate the removal of air bubbles, and the process route is to be simplified as much as possible.

[0024] In step three, precise alignment and bonding are completed through a high-precision vision alignment system, with alignment accuracy controlled within ±5μm. The parts to be bonded and the glass are contacted and pressed together by a robotic arm, with the initial pressing force controlled at 0.05MPa.

[0025] In step four, vacuum treatment is carried out in a vacuum chamber. The vacuum level in the vacuum chamber is evacuated to below 10 Pa, and the pressure holding time is 30 seconds. During the vacuum treatment, the component is placed on a heatable stage, and the stage temperature is maintained at 25°C to maintain the appropriate fluidity of the adhesive.

[0026] In step five, the initial heat curing is carried out in a circulating hot air oven with a temperature control accuracy of ±1℃. During the initial heat curing process, the components are placed flat on a tray with a gap of more than 10mm between them to ensure uniform hot air circulation.

[0027] In step six, quality inspection includes automated optical inspection and manual sampling. Automated optical inspection uses a machine vision system to detect appearance defects in components, including bubbles, foreign objects, scratches, and bonding misalignment. The bubble detection sensitivity is for bubbles with a diameter greater than 50 μm, and the misalignment detection accuracy is ±10 μm. Manual sampling involves sampling components that have passed the automated inspection and checking the bonding interface and preliminary bonding strength using a high-magnification microscope and a shear force tester. The sampling ratio is 5%.

[0028] In step seven, the secondary heat curing of the good products is carried out in a batch oven. The oven is equipped with a forced convection system to ensure temperature uniformity, which is ±2℃. The duration of the secondary heat curing is selected according to the reliability level requirements of the final product. The correspondence between the reliability level requirements and the heat preservation time is as follows: 1 hour for commercial grade products, 1.5 hours for industrial grade products, and 2 hours for automotive grade products.

[0029] In step eight, the rework of defective products specifically includes the following sub-steps: Place the defective component on a heatable rework platform and heat it to 80°C to soften the adhesive layer. Carefully separate the screen and glass from the edge of the component using a precision scraper. Wipe the residual adhesive surface with a lint-free cloth soaked in a special organic solvent until the adhesive layer is completely removed and the surface is smooth. Then, use a plasma cleaner to activate the cleaned screen and glass surface. The processing power is 300W and the processing time is 30 seconds. After the surface treatment is completed, the screen and glass are re-entered into the inkjet printing process of step one as the parts to be bonded.

[0030] Example 2: The screen bonding process of this UV inkjet printing adhesive includes the following steps: Step 1: Inkjet printing. A UV inkjet printing adhesive with photothermal dual curing is used. The adhesive is precisely applied to the screen to be bonded using an inkjet printing device. The inkjet printing time is controlled within 13 seconds, and the coating thickness of the adhesive is controlled within 25μm. Step 2: Optional UV irradiation. Depending on the material of the product to be bonded and the bonding requirements, select UV irradiation to cure the coated adhesive. When using UV irradiation, select UV light with a wavelength of 365nm. Step 3: Glass bonding. The parts to be bonded, coated with UV inkjet printing adhesive, are precisely aligned and bonded to the corresponding glass. Step 4: Vacuum treatment. Place the bonded components into a vacuum device for vacuum treatment to remove any residual air bubbles between the bonding surfaces. Step 5: Initial heat curing. Place the vacuum-treated components in a constant temperature environment of 85℃ for 30 minutes to complete the initial heat curing of the adhesive. Step Six: Quality Inspection. Conduct a quality inspection on the bonded components after the initial heat curing, and classify the components into good and defective products based on the inspection results. Step 7: Secondary heat curing of good products. Place the qualified good components in a constant temperature environment of 80℃ for 1.5 hours to complete the secondary heat curing of the adhesive. Step 8: Repair of defective products. For defective components that fail the inspection, repair them by removing the original adhesive and defective parts from their surfaces, and then re-bonding them according to the process flow from Step 1 to Step 7. The viscosity range of the UV inkjet printing adhesive is 17 cps.

[0031] In step one, the photocuring mechanism of the photothermal dual-curing UV inkjet printing adhesive is to initiate curing by ultraviolet light irradiation with a wavelength of 365nm. The thermal curing conditions of the photothermal dual-curing UV inkjet printing adhesive are to maintain a temperature of 85℃ for 2 hours, depending on the process requirements.

[0032] In step one, the inkjet printing equipment is a precision CNC inkjet printing system. The system presets the coating pattern and thickness through software. The part to be bonded is a screen, and the adhesive is coated on the surface of the screen.

[0033] In step two, the conditions for selecting UV irradiation include: the product to be laminated is a material with high UV transmittance, the adhesive needs to have preliminary positioning ability before lamination, and the production cycle requires rapid pre-curing. The conditions for choosing not to perform UV irradiation include: the parts to be bonded contain materials sensitive to ultraviolet light, the adhesive needs to maintain its fluidity until vacuum processing to facilitate the removal of air bubbles, and the process route is to be simplified as much as possible.

[0034] In step three, precise alignment and bonding are completed through a high-precision vision alignment system, with alignment accuracy controlled within ±5μm. The parts to be bonded and the glass are contacted and pressed together by a robotic arm, with the initial pressing force controlled at 0.1MPa.

[0035] In step four, vacuum treatment is carried out in a vacuum chamber. The vacuum level in the vacuum chamber is evacuated to below 10 Pa, and the pressure holding time is 70 seconds. During the vacuum treatment, the component is placed on a heatable stage, and the stage temperature is maintained at 30°C to maintain the appropriate fluidity of the adhesive.

[0036] In step five, the initial heat curing is carried out in a circulating hot air oven with a temperature control accuracy of ±1℃. During the initial heat curing process, the components are placed flat on a tray with a gap of more than 10mm between them to ensure uniform hot air circulation.

[0037] In step six, quality inspection includes automated optical inspection and manual sampling. Automated optical inspection uses a machine vision system to detect appearance defects in components, including bubbles, foreign objects, scratches, and bonding misalignment. The bubble detection sensitivity is for bubbles with a diameter greater than 50 μm, and the misalignment detection accuracy is ±10 μm. Manual sampling involves sampling components that have passed the automated inspection and checking the bonding interface and preliminary bonding strength using a high-magnification microscope and a shear force tester. The sampling ratio is 5%.

[0038] In step seven, the secondary heat curing of the good products is carried out in a batch oven. The oven is equipped with a forced convection system to ensure temperature uniformity, which is ±2℃. The duration of the secondary heat curing is selected according to the reliability level requirements of the final product. The correspondence between the reliability level requirements and the heat preservation time is as follows: 1 hour for commercial grade products, 1.5 hours for industrial grade products, and 2 hours for automotive grade products.

[0039] In step eight, the rework of defective products specifically includes the following sub-steps: Place the defective component on a heatable rework platform and heat it to 90°C to soften the adhesive layer. Carefully separate the screen and glass from the edge of the component using a precision scraper. Wipe the surface of residual adhesive with a lint-free cloth soaked in a special organic solvent until the adhesive layer is completely removed and the surface is smooth. Then, use a plasma cleaner to activate the cleaned screen and glass surface. The processing power is 400W and the processing time is 45 seconds. After the surface treatment is completed, the screen and glass are re-entered into the inkjet printing process of step one as the parts to be bonded.

[0040] Example 3: The screen bonding process of this UV inkjet printing adhesive includes the following steps: Step 1: Inkjet printing. A UV inkjet printing adhesive with photothermal dual curing is used. The adhesive is precisely applied to the screen to be bonded using an inkjet printing device. The inkjet printing time is controlled within 15 seconds, and the coating thickness of the adhesive is controlled within 30μm. Step 2: Optional UV irradiation. Depending on the material of the product to be bonded and the bonding requirements, select UV irradiation to cure the coated adhesive. When using UV irradiation, select UV light with a wavelength of 365nm. Step 3: Glass bonding. The parts to be bonded, coated with UV inkjet printing adhesive, are precisely aligned and bonded to the corresponding glass. Step 4: Vacuum treatment. Place the bonded components into a vacuum device for vacuum treatment to remove any residual air bubbles between the bonding surfaces. Step 5: Initial heat curing. Place the vacuum-treated components in a constant temperature environment of 90℃ for 30 minutes to complete the initial heat curing of the adhesive. Step Six: Quality Inspection. Conduct a quality inspection on the bonded components after the initial heat curing, and classify the components into good and defective products based on the inspection results. Step 7: Secondary heat curing of good products. Place the qualified good components in a constant temperature environment of 80℃ for 2 hours to complete the secondary heat curing of the adhesive. Step 8: Repair of defective products. For defective components that fail the inspection, repair them by removing the original adhesive and defective parts from their surfaces, and then re-bonding them according to the process flow from Step 1 to Step 7. The viscosity range of the UV inkjet printing adhesive is 25 cps.

[0041] In step one, the photocuring mechanism of the photothermal dual-curing UV inkjet printing adhesive is to initiate curing by ultraviolet light irradiation with a wavelength of 365nm. The thermal curing conditions of the photothermal dual-curing UV inkjet printing adhesive are to maintain a temperature of 90℃ for 3 hours, depending on the process requirements.

[0042] In step one, the inkjet printing equipment is a precision CNC inkjet printing system. The system presets the coating pattern and thickness through software. The part to be bonded is a screen, and the adhesive is coated on the surface of the screen.

[0043] In step two, the conditions for selecting UV irradiation include: the product to be laminated is a material with high UV transmittance, the adhesive needs to have preliminary positioning ability before lamination, and the production cycle requires rapid pre-curing. The conditions for choosing not to perform UV irradiation include: the parts to be bonded contain materials sensitive to ultraviolet light, the adhesive needs to maintain its fluidity until vacuum processing to facilitate the removal of air bubbles, and the process route is to be simplified as much as possible.

[0044] In step three, precise alignment and bonding are completed through a high-precision vision alignment system, with alignment accuracy controlled within ±5μm. The parts to be bonded and the glass are contacted and pressed together by a robotic arm, with the initial pressing force controlled at 0.2MPa.

[0045] In step four, vacuum treatment is carried out in a vacuum chamber. The vacuum level in the vacuum chamber is evacuated to below 10 Pa, and the pressure holding time is 120 seconds. During the vacuum treatment, the component is placed on a heatable stage, and the stage temperature is maintained at 40°C to maintain the appropriate fluidity of the adhesive.

[0046] In step five, the initial heat curing is carried out in a circulating hot air oven with a temperature control accuracy of ±1℃. During the initial heat curing process, the components are placed flat on a tray with a gap of more than 10mm between them to ensure uniform hot air circulation.

[0047] In step six, quality inspection includes automated optical inspection and manual sampling. Automated optical inspection uses a machine vision system to detect appearance defects in components, including bubbles, foreign objects, scratches, and bonding misalignment. The bubble detection sensitivity is for bubbles with a diameter greater than 50 μm, and the misalignment detection accuracy is ±10 μm. Manual sampling involves sampling components that have passed the automated inspection and checking the bonding interface and preliminary bonding strength using a high-magnification microscope and a shear force tester. The sampling ratio is 5%.

[0048] In step seven, the secondary heat curing of the good products is carried out in a batch oven. The oven is equipped with a forced convection system to ensure temperature uniformity, which is ±2℃. The duration of the secondary heat curing is selected according to the reliability level requirements of the final product. The correspondence between the reliability level requirements and the heat preservation time is as follows: 1 hour for commercial grade products, 1.5 hours for industrial grade products, and 2 hours for automotive grade products.

[0049] In step eight, the rework of defective products specifically includes the following sub-steps: Place the defective component on a heatable rework platform and heat it to 100°C to soften the adhesive layer. Carefully separate the screen and glass from the edge of the component using a precision scraper. Wipe the residual adhesive surface with a lint-free cloth soaked in a special organic solvent until the adhesive layer is completely removed and the surface is smooth. Then, use a plasma cleaner to activate the cleaned screen and glass surface. The processing power is 500W and the processing time is 60 seconds. After the surface treatment is completed, the screen and glass are re-entered into the inkjet printing process of step one as the parts to be bonded.

[0050] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not use inkjet printing technology, but uses traditional squeegee coating technology to apply the adhesive. The squeegee coating time is 40 seconds, and the adhesive layer thickness is controlled at 300μm.

[0051] Comparative Example 2 differs from Example 2 in that: this comparative example does not include an optional UV light irradiation step, but instead forces all samples to undergo UV light irradiation with a wavelength of 365nm for pre-curing after inkjet printing and coating.

[0052] Comparative Example 3 differs from Example 3 in that: after the glass is bonded, no vacuum treatment step is performed in this comparative example.

[0053] Comparative Example 4 differs from Example 3 in that: this comparative example does not have independent quality inspection and classification steps, all components are directly subjected to a second heat curing for 2 hours after the initial heat curing, and no rework process is set.

[0054] The screen bonding components prepared by the screen bonding process implemented in Examples 1-3 and Comparative Examples 1-4 were subjected to performance and efficiency tests. The test items and test methods are as follows: Adhesive application efficiency and material utilization test: Record the time required for a single component to complete adhesive application, weigh the average amount of adhesive consumed by a single component, and calculate the percentage comparison with the traditional scraping adhesive process.

[0055] Adhesive layer uniformity and bubble rate test: The thickness uniformity of the adhesive layer inside the bonding component and the number of bubbles with a diameter greater than 50μm at the interface were detected by ultrasonic scanning microscope, and the bubble rate was counted.

[0056] Adhesion strength test: A push-pull force tester is used to conduct a 90-degree peel strength test to evaluate the bonding strength between the screen and the glass.

[0057] Process yield and rework cost test: Statistically analyze the total yield of batch production, and compare and analyze the percentage of defective products that can be successfully reused after the rework process, as well as the material loss cost caused by the inability to rework.

[0058] The test data of the screen bonding components prepared by the processes in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below: Table 1 - Test data of screen bonding components prepared by the process By comparing and analyzing the data in the table, it can be seen that the screen bonding components prepared using the processes in Examples 1-3 are significantly superior to those prepared using the processes in Comparative Examples 1-4 in terms of overall performance and production efficiency. This indicates that by using inkjet printing equipment and a compatible UV inkjet printing adhesive for coating, the adhesive can be precisely and evenly applied to the surface to be bonded. This solves the problems of excessively long coating time in traditional scraping processes, which restricts production cycle, and excessive adhesive thickness leading to serious material waste, poor uniformity, and easy bubble formation. This ensures the high efficiency and economy of screen bonding production, improves material utilization and bonding quality. By using a photothermal dual-curing UV inkjet printing adhesive and setting optional UV irradiation steps and flexibly adjustable thermosetting parameters in the process flow, the bonding process can be optimized according to the surface to be bonded. Based on the specific materials and bonding requirements of the product, the process allows for the independent selection of whether to perform UV pre-curing and to match different thermal curing conditions. This solves the problem of fixed curing processes and inflexible adjustments in traditional processes, enabling the screen bonding process to adapt to a wider range of product types and production requirements. This improves the flexibility and applicability of the process. By introducing vacuum treatment after glass bonding to remove interface bubbles, and setting up a complete follow-up process that includes initial thermal curing, quality inspection, secondary thermal curing of good products, and rework of defective products, the process can systematically solve the problems of loose bonding, unstable yield, ineffective reuse of defective products, and time-consuming and rigid secondary curing caused by uneven adhesive layers and insufficient curing in traditional processes. This ensures the reliability, stability, and final yield of the bonded components, and optimizes production resources and efficiency.

[0059] By comparing and analyzing the relevant data in the table, it can be seen that the products prepared by the screen bonding process of the UV inkjet printing adhesive provided by the present invention not only have higher production efficiency and better material utilization, but also show advantages in adhesive layer uniformity, interface bonding strength and final product yield. This indicates that the screen bonding process provided by the present invention has better overall performance.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A screen bonding process for UV inkjet printing adhesive, characterized in that, Includes the following steps: Step 1: Inkjet printing. A UV inkjet printing adhesive with photothermal dual curing is used. The adhesive is precisely applied to the surface of the screen or glass to be bonded using an inkjet printing device. The inkjet printing time is controlled at 10-15 seconds, and the coating thickness of the adhesive is controlled at 20-30μm. Step 2: Optional UV irradiation. Depending on the material of the product to be bonded and the bonding requirements, choose to cure the coated adhesive with UV light or not. When using UV light, select UV light with a wavelength of 365nm or 395nm. Step 3: Glass bonding. The parts to be bonded, coated with UV inkjet printing adhesive, are precisely aligned and bonded to the corresponding glass. Step 4: Vacuum treatment. Place the bonded components into a vacuum device for vacuum treatment to remove any residual air bubbles between the bonding surfaces. Step 5: Initial heat curing. Place the vacuum-treated components in a constant temperature environment of 80-90℃ for 30 minutes to complete the initial heat curing of the adhesive. Step Six: Quality Inspection. Conduct a quality inspection on the bonded components after the initial heat curing, and classify the components into good and defective products based on the inspection results. Step 7: Secondary heat curing of good products. Place the qualified good components in a constant temperature environment of 80℃ for 1-2 hours to complete the secondary heat curing of the adhesive. Step 8: Repair of defective products. For defective components that fail the inspection, repair them by removing the original adhesive and defective parts from their surfaces, and then re-bonding them according to the process flow from Step 1 to Step 7. The viscosity range of the UV inkjet printing adhesive is 10-25 cps.

2. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step one, the photocuring mechanism of the photothermal dual-curing UV inkjet printing adhesive is to initiate curing by ultraviolet light irradiation, wherein the wavelength of the ultraviolet light is 365nm or 395nm, and the thermal curing condition of the photothermal dual-curing UV inkjet printing adhesive is to keep it at a temperature of 80-90℃, wherein the holding time is selected as 20 minutes, 2 hours or 3 hours according to the process requirements.

3. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step one, the inkjet printing equipment is a precision CNC inkjet printing system. The system presets the coating pattern and thickness through software. The component to be bonded is a screen or a glass substrate. The adhesive is applied to the surface of the screen or the surface of the glass substrate.

4. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step two, the conditions for selecting UV irradiation include: the product to be bonded is a material with high UV transmittance, the adhesive needs to have preliminary positioning ability before bonding, and the production cycle requires rapid pre-curing. The conditions for choosing not to perform UV irradiation include: the parts to be bonded contain materials sensitive to ultraviolet light, the adhesive needs to maintain its fluidity until vacuum processing to facilitate the removal of air bubbles, and the process route is to be simplified as much as possible.

5. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step three, the precise alignment and bonding is completed by a high-precision vision alignment system, with the alignment accuracy controlled within ±5μm. The component to be bonded and the glass are contacted and pressed together by a robotic arm or a precision platform, with the initial pressing force controlled between 0.05-0.2MPa.

6. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step four, the vacuum treatment is carried out in a vacuum chamber, where the vacuum level is evacuated to below 10 Pa and the pressure holding time is 30-120 seconds. During the vacuum treatment, the component is placed on a heatable platform, and the platform temperature is maintained at 25-40°C.

7. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step five, the initial heat curing is carried out in a circulating hot air oven or tunnel oven with a temperature control accuracy of ±1℃. During the initial heat curing process, the components are placed flat on a tray with a gap of more than 10mm between them.

8. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step six, the quality inspection includes automated optical inspection and manual sampling. The automated optical inspection uses a machine vision system to detect appearance defects in the components, including bubbles, foreign objects, scratches, and bonding misalignment. The bubble detection sensitivity is for bubbles with a diameter greater than 50 μm, and the misalignment detection accuracy is ±10 μm. The manual sampling inspection samples the components that have passed the automated inspection and checks the bonding interface and preliminary bonding strength using a high-magnification microscope and a shear force tester. The sampling ratio is 5%.

9. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step seven, the secondary heat curing of the good product is carried out in a batch oven equipped with a forced convection system and a temperature uniformity of ±2℃. The duration of the secondary heat curing is selected according to the reliability level requirements of the final product. The correspondence between the reliability level requirements and the heat preservation time is as follows: 1 hour for commercial grade products, 1.5 hours for industrial grade products, and 2 hours for automotive grade or high reliability products.

10. A screen attachment process of a screen attachment UV inkjet printing glue according to claim 1, characterized in that, In step eight, the defective product rework specifically includes the following sub-steps: placing the defective component on a heatable rework platform and heating it to 80-100℃ to soften the adhesive layer; carefully separating the screen and glass from the edge of the component using a precision scraper or suction tool; wiping the residual adhesive surface with a lint-free cloth soaked in a special organic solvent until the adhesive layer is completely removed and the surface is smooth; then using a plasma cleaner to activate the cleaned screen and glass surface, with a processing power of 300-500W and a processing time of 30-60 seconds; after completing the surface treatment, the screen and glass, as the parts to be bonded, re-enter the inkjet printing process in step one.

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