Chip encapsulation adhesive film, preparation method and application thereof
By combining epoxy resin with nanomaterials and latent curing agents, the problems of chip encapsulation films being brittle at room temperature and experiencing a sharp drop in viscosity at high temperatures are solved, achieving a stable encapsulation process and excellent encapsulation effect, meeting the high precision and high performance requirements of chip encapsulation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG HUINA NEW MATERIAL MANUFACTURING CO LTD
- Filing Date
- 2026-04-17
- Publication Date
- 2026-06-12
AI Technical Summary
Existing chip encapsulation films are prone to brittle adhesion at room temperature, and at high temperatures, the viscosity drops sharply, causing adhesive overflow and contamination of the cavity. It is difficult to balance morphological stability and self-leveling performance.
By combining epoxy resin with nano-calcium carbonate, nano-silicon fiber, aluminum hydroxide, latent curing agent and organic urea accelerator, and by controlling the stirring frequency and temperature, a semi-cured structure with both strength and ductility is formed. Combined with a suitable baking process, low-to-medium temperature latent curing and subsequent high-temperature curing are achieved, avoiding rheological changes in the adhesive layer.
The processing is stable, the shelf life is long, the cured product has excellent comprehensive performance, high packaging precision, and good resistance to glue overflow, ensuring high-strength protection and electrical insulation performance of chip packaging.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer sealing materials technology, and more specifically, to a chip encapsulation film, its preparation method, and its application. Background Technology
[0002] Epoxy resin is widely used for sealing and protecting electronic components due to its advantages such as strong adhesion, high hardness, high mechanical strength, resistance to media, aging resistance, and good electrical insulation properties, especially in the field of chip packaging, where it plays an irreplaceable role. In practical applications, adhesive films are a common form in chip packaging. These films are cut to the required thickness and size for the chip, and after removing the protective film, they are directly applied to the chip surface. Through a series of processes including debubbling, pressurization, and heating, the adhesive film completely encapsulates the chip, achieving its encapsulation and protection function.
[0003] To meet the requirements of automated encapsulation processes, such films need to possess good morphological stability and flexibility. They must not become brittle during room-temperature cutting and processing, and must also ensure excellent mechanical properties and temperature resistance during high-temperature encapsulation. However, existing technologies (such as patent CN119592012A) mainly rely on introducing high molecular weight polymers into the resin system to achieve a film-like physical form. This often results in insufficient modulus of the film in the semi-cured state, making it extremely sensitive to mechanical pressure during production and prone to permanent indentations that affect the smoothness of the appearance. More seriously, such physical thickening systems will experience significant viscosity collapse due to heat during the high-temperature encapsulation stage, causing severe adhesive overflow and making it difficult to meet the micron-level control requirements for thickness and contour in precision encapsulation. On the other hand, attempting to forcibly establish a framework during the pre-reaction stage by introducing a highly active curing system will lead to localized burst polymerization during production and premature embrittlement of the film at room temperature due to uncontrollable curing kinetics. This creates a vicious cycle where "improving film formation means losing rheological control, and increasing reactivity means losing storage stability." Summary of the Invention
[0004] To overcome the shortcomings of the prior art, such as the chip encapsulation adhesive film being prone to brittle adhesion at room temperature and causing overflow and contamination of the cavity due to a sudden drop in viscosity during high-temperature encapsulation, thus failing to simultaneously ensure morphological stability and self-leveling performance, this invention provides an adhesive film for chip encapsulation. Another object of the present invention is to provide a method for preparing an adhesive film for chip packaging; Another object of the present invention is to provide an application of a chip encapsulation film.
[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A chip encapsulation film comprises the following raw materials in parts by weight: 100 parts epoxy resin, 40-60 parts nano calcium carbonate, 20-40 parts silicon dioxide, 20-40 parts aluminum hydroxide, 10-20 parts nano silicon-based fibers, 5-10 parts amine latent curing agent, 5-10 parts dicyandiamide, and 1-2 parts organic urea accelerator.
[0006] Preferably, the dicyandiamide is a white crystalline particle with an active hydrogen equivalent of 18-25; The organic urea accelerator is a light yellow crystalline granule with a melting point of 150~160℃ and a moisture content of ≤0.5%.
[0007] Preferably, the silica particles have a diameter of 3-8 micrometers and a moisture content of ≤0.3%; the aluminum hydroxide particles have a diameter of 2-6 micrometers and a moisture content of ≤0.3%. Preferably, the composition also includes the following raw materials in parts by weight: 0.1 to 0.5 parts of defoamer and 0.05 to 0.1 parts of carbon black.
[0008] Preferably, the defoamer is a solvent-free silicone-based defoamer; Preferably, the epoxy resin is at least one of bisphenol A type epoxy resin and bisphenol F epoxy resin; the epoxy equivalent is 150~200 g / eq, and the viscosity at 25°C is 3000~15000cps.
[0009] Furthermore, the nano-calcium carbonate particles have a diameter of 20-60 nm and are surface-treated with borate ester.
[0010] Furthermore, the nano-silicon-based fibers have a diameter of 20-50 nm and a length of 600-1500 nm, and are surface-treated with a silane coupling agent.
[0011] A method for preparing the adhesive film for chip encapsulation includes the following steps: S1. Stir and mix epoxy resin, nano calcium carbonate, silicon dioxide, aluminum hydroxide, and nano silicon-based fibers. S2. Add dicyandiamide and organic urea accelerator and stir to mix; S3. Add modified amine curing agent and stir to mix; S4. The mixed adhesive is applied to the lower release film and then laminated with the upper release film. After being pressed by rollers, baked, and cooled, the adhesive film for chip packaging is obtained.
[0012] Furthermore, during step S3, the material temperature is controlled to be below 40°C.
[0013] Preferably, the stirring frequency during steps S1 to S2 is 25 to 35 Hz and the dispersion frequency is 20 to 30 Hz; the stirring frequency during step S3 is 20 to 25 Hz and the dispersion frequency is 10 to 20 Hz.
[0014] Preferably, step S1 involves stirring and mixing for 20-40 minutes; step S2 involves stirring and mixing for 30-50 minutes; and step S3 involves stirring and mixing for 10-15 minutes.
[0015] Furthermore, after the S4 roller forms the film, it is baked at 80~100℃ for 30~20 min.
[0016] Furthermore, Preferably, in step S4, the pressure roller forms a film with a thickness of 250±5 μm.
[0017] Preferably, S4 is cut after cooling to obtain the encapsulating film for the chip.
[0018] Preferably, steps S1 to S3 are performed under a vacuum of -0.09 to -0.1 MPa.
[0019] Preferably, after S3 is mixed, it is aged at room temperature for 12-24 hours.
[0020] Preferably, epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, nano-silica fiber, defoamer, and carbon black are initially mixed, and then stirred for 20-40 minutes under the following conditions: vacuum degree -0.09~-0.1 MPa, material temperature controlled below 40°C by a cooling device, stirring frequency 25~35 Hz, dispersion frequency 20~30 Hz; dicyandiamide and organic urea accelerator are added, and the mixture is stirred for 30-50 minutes under the following conditions: vacuum degree -0.09~-0.1 MPa, material temperature controlled below 40°C by a cooling device, stirring frequency 25~35 Hz, dispersion frequency 20~30 Hz; modified amine curing agent is added, and the mixture is stirred for 10-15 minutes under the following conditions: vacuum degree -0.09~-0.1 MPa, material temperature controlled below 40°C by a cooling device, stirring frequency 20~25 Hz, dispersion frequency 10~20 Hz; finally, the mixture is cured at room temperature for 12~24 minutes. h; Apply the adhesive evenly to the lower release film, then cover the upper release film with the adhesive, and roll it into the required film. Bake at 80~100℃, cool, cut, and store in a freezer with the temperature set below -15℃; the resulting film is the chip packaging film.
[0021] An application of the aforementioned chip encapsulation film, used in semiconductor chip encapsulation.
[0022] Further, the process includes the following steps: after the preserved chip encapsulation film is brought to room temperature, the upper release film is peeled off and then attached to the surface of the semiconductor chip; under heating and pressure, the film is stretched to wrap the chip, and after vacuum degassing, the lower release film is peeled off; and then the temperature is raised for curing.
[0023] Furthermore, the encapsulating film for the chip is stored below -15°C, and the room temperature recovery time is 30~60 min; it is heated and pressurized at 60~80°C and 0.05~0.15 MPa; and then cured at 140~160°C.
[0024] Preferably, the heating and pressurization are carried out for 8-15 seconds; vacuum degassing is performed for 50-70 seconds; and curing is carried out at 140-160°C for 40-60 minutes.
[0025] This invention utilizes epoxy resin combined with two or more latent curing agents. Taking advantage of the differences in their gelation temperature and curing rate, and combining this with a suitable baking process, the low-to-medium temperature latent curing agents preferentially participate in the reaction, forming a semi-cured structure with both strength and ductility. Simultaneously, by using a small amount of modified amine curing agent to react with the epoxy resin, the semi-cured, semi-flow state of the system is further stabilized, ultimately obtaining a soft adhesive film that does not become brittle at room temperature and exhibits excellent morphological stability. This semi-cured substrate can act as a skeletal support during subsequent heated bonding, preventing rheological changes in the adhesive layer and effectively solving the dimensional stability problem of ultra-thin adhesive films during processing and storage. In use, the adhesive film is applied to the chip surface, and negative pressure bubble-blowing extends the film to wrap around the chip. Mold pressure achieves tight bonding, and the unreacted low-to-medium temperature latent curing agents complete the subsequent curing reaction, forming a protective layer that meets the encapsulation requirements, thus achieving chip encapsulation protection.
[0026] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: 1. Stable processing and long shelf life. The adhesive material remains stable during the mixing stage. In a 30 kg scale preparation process, the colloid remains stable with no significant increase in viscosity. The viscosity increase is less than 10% after storage at 27℃ for 3 months, and the viscosity change is less than 2% when stored at a low temperature of 0~5℃. The finished adhesive film can be stably stored at a low temperature of -15℃ for no less than 3 months, and its processing activity can be restored after being placed at room temperature for 30~60 minutes, with a wide operating window.
[0027] 2. The cured product exhibits excellent overall performance. The cured product achieves a Shore D hardness of 83, a tensile strength exceeding 60 MPa (maximum 62.1 MPa), and a Tg of 105~115℃. Simultaneously, the product achieves a UL94 V-0 flame retardant rating, a dielectric strength of not less than 25 kV / mm, and a thermal conductivity of 0.6 W / mK. While providing high-strength physical protection, it also ensures excellent electrical insulation and heat dissipation performance.
[0028] 3. High encapsulation precision and excellent resistance to adhesive overflow. The adhesive film does not melt or flow during the curing process at 150℃, maintaining a stable state without adhesive overflow. This allows for complete encapsulation of the chip, significantly improving the chip encapsulation yield. The adhesive film is manufactured with fixed thickness and size, making it convenient to handle, minimizing errors, and reducing mixing steps and problems caused by operational mistakes during mixing. Attached Figure Description
[0029] Figure 1 This is a diagram showing the state of the rubber compound. Figure 2 This is a diagram of a semi-cured adhesive film. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.
[0031] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.
[0032] Dicyandiamide is a white crystalline granule with an active hydrogen equivalent of 18-25; the organic urea accelerator is a light yellow crystalline granule with a melting point of 150-160℃ and a moisture content of ≤0.5%; the silica has a particle size of 3-8 micrometers and a moisture content of ≤0.3%; the aluminum hydroxide has a particle size of 2-6 micrometers and a moisture content of ≤0.3%; the nano-calcium carbonate has a particle size of 20-60 nm and is surface-treated with borate ester; the nano-silicon-based fibers (SiO2 nanowires) have a diameter of 20-50 nm and a length of 600-1500 nm and are surface-treated with silane coupling agent; the release film is a PET film, with the upper film being white and flexible, with a temperature resistance of not less than 100℃ and a release force of 5-10 g; the lower film is transparent and slightly rigid, with a temperature resistance of not less than 160℃ and a release force of 100-150 g.
[0033] Example 1 1. Raw material composition 100 parts epoxy resin, 40 parts nano calcium carbonate, 40 parts silica, 40 parts aluminum hydroxide, 0.1 parts defoamer, 5 parts modified amine curing agent, 10 parts dicyandiamide, 2 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 20 parts by weight of bisphenol A epoxy resin and 80 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7000 cps. 2. Preparation of encapsulant film for chip packaging After initial mixing of the epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black, the mixture was stirred for 20 min under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 25 Hz, and dispersion frequency 30 Hz. Then, dicyandiamide and organic urea accelerator were added and stirred, followed by degassing under vacuum degree -0.09 MPa, stirring frequency 25 Hz, and dispersion frequency 20 Hz, for 40 min. Finally, modified amine curing agent was added and the mixture was stirred for 15 min under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 20 Hz, and dispersion frequency 10 Hz. The mixture was then cured at room temperature for 12-24 h. The adhesive is evenly applied to the lower release film, and then the upper release film is laminated on the adhesive. The film is then rolled into the required film (250±5 μm), baked at 80~100℃, cooled at room temperature for 10~20 min, cut into the required size, and stored in a freezer with the temperature set below -15℃. The resulting film is the adhesive for chip packaging.
[0034] Example 2 1. Raw material composition 100 parts epoxy resin, 40 parts nano calcium carbonate, 20 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 8 parts modified amine curing agent, 8 parts dicyandiamide, 2 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 40 parts by weight of bisphenol A epoxy resin and 60 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 175 g / eq, and the viscosity at 25℃ is 8500 cps. 2. Preparation of encapsulant film for chip packaging After initial mixing of the epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black, the mixture was stirred for 20 min under the following conditions: vacuum degree -0.1 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 30 Hz, and dispersion frequency 20 Hz. Then, dicyandiamide and organic urea accelerator were added and stirred, followed by degassing under vacuum degree -0.1 MPa, stirring frequency 30 Hz, and dispersion frequency 20 Hz, for another 30 min. Finally, modified amine curing agent was added and the mixture was stirred for 10 min under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 25 Hz, and dispersion frequency 20 Hz. The mixture was then cured at room temperature for 12-24 h. The adhesive is evenly applied to the lower release film, and then the upper release film is laminated on the adhesive. The film is then rolled into the required film (250±5 μm), baked at 80~100℃, cooled at room temperature for 10~20 min, cut into the required size, and stored in a freezer with the temperature set below -15℃. The resulting film is the adhesive for chip packaging.
[0035] Example 3 1. Raw material composition 100 parts epoxy resin, 60 parts nano calcium carbonate, 20 parts silica, 40 parts aluminum hydroxide, 0.5 parts defoamer, 10 parts modified amine curing agent, 8 parts dicyandiamide, 2 parts organic urea accelerator, and 0.05 parts carbon black; The epoxy resin is composed of 40 parts by weight of bisphenol A epoxy resin and 60 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 175 g / eq, and the viscosity at 25℃ is 8500 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed. The mixture is then stirred for 25 minutes under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40°C by a cooling device, stirring frequency 35 Hz, and dispersion frequency 20 Hz. Dicyandiamide and organic urea accelerator are then added and stirred. The mixture is then defoamed under vacuum degree -0.09 MPa, stirring frequency 35 Hz, and dispersion frequency 20 Hz, and stirred for 45 minutes. Finally, a modified amine curing agent is added and the mixture is stirred for 10 minutes under the following conditions: vacuum degree -0.1 MPa, material temperature controlled below 40°C by a cooling device, stirring frequency 20 Hz, and dispersion frequency 20 Hz. The final mixture is then cured at room temperature for 12–24 hours. The adhesive is evenly applied to the lower release film, and then the upper release film is laminated on the adhesive. The film is then rolled into the required film (250±5 μm), baked at 80~100℃, cooled at room temperature for 10~20 min, cut into the required size, and stored in a freezer with the temperature set below -15℃. The resulting film is the adhesive for chip packaging.
[0036] Example 4 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate, 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 10 parts modified amine curing agent, 10 parts dicyandiamide, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 30 parts by weight of bisphenol A epoxy resin and 70 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 173 g / eq, and the viscosity at 25℃ is 8100 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed and then stirred for 25 min under vacuum of -0.09 MPa, with the material temperature controlled below 40℃ by a cooling device, a stirring frequency of 30 Hz, and a dispersion frequency of 20 Hz. Modified amine curing agent, dicyandiamide, and organic urea accelerator are added and stirred, then degassed under vacuum of -0.09 MPa, with a stirring frequency of 30 Hz and a dispersion frequency of 20 Hz, and stirred for 50 min. The adhesive is then cured at room temperature for 12–24 h. The adhesive is evenly coated onto the lower release film, and then the upper release film is laminated onto the adhesive. The mixture is then rolled into the desired film (250±5 μm), baked at 80–100℃, cooled at room temperature for 10–20 min, cut to the required size, and stored in a freezer at a temperature below -15℃. The resulting film is the adhesive for chip encapsulation.
[0037] Example 5 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate, 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 10 parts modified amine curing agent, 10 parts dicyandiamide, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 20 parts by weight of bisphenol A epoxy resin and 80 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7000 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed and then stirred for 25 min under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 35 Hz, and dispersion frequency 25 Hz. Modified amine curing agent, dicyandiamide, and organic urea accelerator are added and stirred, then degassed under vacuum degree -0.09 MPa, stirring frequency 35 Hz, and dispersion frequency 20 Hz, and stirred for 50 min. The adhesive is then cured at room temperature for 12-24 h. The adhesive is evenly coated onto the lower release film, and then the upper release film is laminated onto the adhesive. The mixture is then rolled into the desired film (250±5 μm), baked at 80-100℃, cooled at room temperature for 10-20 min, cut to the required size, and stored in a freezer at a temperature below -15℃. The resulting film is the adhesive for chip encapsulation.
[0038] Comparative Example 1 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate, 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 15 parts modified amine curing agent, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 30 parts by weight of bisphenol A epoxy resin and 70 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7200 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed and then stirred for 25 minutes under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 35 Hz, and dispersion frequency 25 Hz. Modified amine curing agent, dicyandiamide, and organic urea accelerator are added and stirred. The mixture is then degassed under vacuum degree -0.09 MPa, stirring frequency 35 Hz, and dispersion frequency 20 Hz, and stirred for 50 minutes. The adhesive is cured at room temperature for 12-24 hours. Using a laminator with PET film, a film of the required thickness and size is produced. A semi-cured film is then obtained by using a tunnel oven at a specific temperature and time. After cooling at room temperature for 10-20 minutes, it is cut to the required size and stored in a freezer set at a temperature below -15℃. The resulting film is the adhesive film for chip encapsulation.
[0039] Comparative Example 2 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate, 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 20 parts dicyandiamide, and 0.1 parts carbon black; The epoxy resin is composed of 20 parts by weight of bisphenol A epoxy resin and 80 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7000 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed. The mixture is then stirred for 25 minutes under vacuum of -0.09 MPa, with the material temperature controlled below 40°C by a cooling device, a stirring frequency of 35 Hz, and a dispersion frequency of 25 Hz. Dicyandiamide is then added and stirred, followed by degassing under vacuum of -0.09 MPa, a stirring frequency of 35 Hz, and a dispersion frequency of 20 Hz, for another 50 minutes. The mixture is then cured at room temperature for 12-24 hours. Using a laminator and PET film, a film of the required thickness and size is produced. A semi-cured film is then obtained in a tunnel oven at a specific temperature and time. This semi-cured film is uniformly coated onto a 0.05 mm thick transparent PET film, and then another 0.05 mm thick transparent PET film is applied to the mixture. The mixture is then rolled to a thickness of 0.3 ± 0.02 mm and left at room temperature for 12 hours, followed by cooling at room temperature for 10-20 minutes. After min, cut it to the required size and store it in a freezer with the temperature set below -15°C; the result is the encapsulating film for chip packaging.
[0040] Comparative Example 3 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate, 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 15 parts modified amine curing agent, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 30 parts by weight of bisphenol A epoxy resin and 70 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7200 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed and then stirred for 30 min under the following conditions: vacuum degree -0.09 MPa, material temperature controlled at 60℃±2℃ by a cooling device, stirring frequency 40 Hz, and dispersion frequency 35 Hz. Modified amine curing agent, dicyandiamide, and organic urea accelerator are added and stirred, then degassed under vacuum degree -0.09 MPa, stirring frequency 40 Hz, and dispersion frequency 35 Hz, and stirred for 50 min. The adhesive is then cured at room temperature for 12-24 h. Using a laminator with PET film, a film of the required thickness and size is produced. A semi-cured film is obtained by using a tunnel oven at a specific temperature and time. After cooling at room temperature for 10-20 min, it is cut to the required size and stored in a freezer at a temperature below -15℃. The resulting film is the adhesive film for chip encapsulation.
[0041] Comparative Example 4 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate, 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 15 parts modified amine curing agent, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 30 parts by weight of bisphenol A epoxy resin and 70 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7200 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, modified amine curing agent, dicyandiamide, and organic urea accelerator described above are mixed by stirring. After initial mixing and degassing under a vacuum of -0.09 MPa, the mixture is stirred for 20 min under a vacuum of -0.09 MPa, with the material temperature controlled below 40°C by a cooling device, a stirring frequency of 35 Hz, and a dispersion frequency of 20 Hz. Nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black are then added, and the mixture is stirred for 35 min under a stirring frequency of 30 Hz and a dispersion frequency of 20 Hz. The adhesive is then cured at room temperature for 12-24 h. Using a laminator and PET film, the adhesive film of the required thickness and size is produced. A semi-cured adhesive film is then produced in a tunnel oven at a specific temperature and time. After cooling at room temperature for 10-20 min, the film is cut to the required size and stored in a freezer at a temperature below -15°C. The resulting film is the adhesive film for chip encapsulation.
[0042] Comparative Example 5 1. Raw material composition 100 parts epoxy resin, 80 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 15 parts modified amine curing agent, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 30 parts by weight of bisphenol A epoxy resin and 70 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7200 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate, silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed and then stirred for 30 minutes under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 40 Hz, and dispersion frequency 35 Hz. Modified amine curing agent, dicyandiamide, and organic urea accelerator are added and stirred. The mixture is then degassed under vacuum degree -0.09 MPa, stirring frequency 40 Hz, and dispersion frequency 35 Hz, and stirred for 50 minutes. The adhesive is cured at room temperature for 12-24 hours. Using a laminator with PET film, a film of the required thickness and size is produced. A semi-cured film is then obtained by using a tunnel oven at a specific temperature and time. After cooling at room temperature for 10-20 minutes, it is cut to the required size and stored in a freezer at a temperature below -15℃. The resulting film is the adhesive film for chip encapsulation.
[0043] Comparative Example 6 1. Raw material composition 100 parts epoxy resin, 50 parts nano calcium carbonate (unmodified), 30 parts silica, 40 parts aluminum hydroxide, 0.2 parts defoamer, 15 parts modified amine curing agent, 1.5 parts organic urea accelerator, and 0.1 parts carbon black; The epoxy resin is composed of 30 parts by weight of bisphenol A epoxy resin and 70 parts by weight of bisphenol F epoxy resin; the epoxy equivalent is 170 g / eq, and the viscosity at 25℃ is 7200 cps. 2. Preparation of encapsulant film for chip packaging The epoxy resin, nano-calcium carbonate (unmodified), silica, aluminum hydroxide, defoamer, and carbon black described above are initially mixed and then stirred for 30 min under the following conditions: vacuum degree -0.09 MPa, material temperature controlled below 40℃ by a cooling device, stirring frequency 40 Hz, and dispersion frequency 35 Hz. Modified amine curing agent, dicyandiamide, and organic urea accelerator are added and stirred, then degassed under vacuum degree -0.09 MPa, stirring frequency 40 Hz, and dispersion frequency 35 Hz, and stirred for 50 min. The adhesive is then cured at room temperature for 12-24 h. Using a laminator with PET film, a film of the required thickness and size is produced. A semi-cured film is obtained by using a tunnel oven at a specific temperature and time. After cooling at room temperature for 10-20 min, it is cut to the required size and stored in a freezer set at a temperature below -15℃. The resulting film is the adhesive film for chip encapsulation.
[0044] Performance testing The performance tests of the chip encapsulating films prepared according to various embodiments of the present invention are as follows: Specific gravity was determined according to GB / T 533-2008; The Shore D hardness was determined according to GB / T 531.2-2009 (after heat curing). Flame retardancy was determined according to UL94 (after heat curing); Tensile strength and elongation at break (after heat curing) were determined according to GB / T 528-2009. Dielectric strength was determined according to GB / T 1695-2005 (after heat curing); Thermal conductivity was measured according to ASTM 5470; The glass transition temperature was determined according to IFC 1006; The coefficient of thermal expansion was determined by TMA (after heat curing); The viscosity change of 30 kg of rubber was measured throughout the entire rubber preparation process and after 90 days of storage at 27℃ / 0~5℃, according to GB / T2794-2022. According to GB / T1731-2020, the flexibility of the film stored at -15℃ for 90 days after rewarming was tested, and the processing status after rewarming at room temperature for 30~60 minutes was verified simultaneously.
[0045] After the adhesive film is left at room temperature for 30-60 minutes, the white PET film is peeled off and bonded to the surface of the filter chip. A laminator is used to apply a pressure of 0.1 MPa to the film surface, and the film is heated at 60-80°C for 8-15 seconds. A vacuum system is then used to achieve a vacuum of -0.1 MPa, which is maintained for 50-70 seconds. Under this negative pressure, the adhesive film stretches and covers the chip. The coated chip is then placed in a tunnel oven at a controlled temperature of 140-160°C for 40-60 minutes for curing.
[0046] After removing the chip and allowing it to cool, peel off the transparent PET film and observe: ① Whether the chip is completely encased with no exposed chips, and whether each chip has a clear outline and a smooth surface. ② Scribe the chip, removing the adhesive without chip detachment. ③ Take eight points on the substrate (four corners × 4, four sides × 4, and eight on the surface) and magnify them 50 times to observe the surface and side voids. ④ Open the cover and observe the material leakage / seepage. ⑤ Test for Uhast failure under high-acceleration temperature and humidity.
[0047] The performance metrics obtained from the tests are shown in Table 1.
[0048] Analysis and Explanation Table 1 Performance Indicators of Adhesive Films for Chip Packaging
[0049] The chip encapsulation film prepared in the examples exhibits excellent overall performance and good processing and storage stability: the adhesive material remains stable during the mixing stage; there is no significant viscosity increase when preparing the adhesive at a scale of 30 kg; the viscosity increase is ≤10% after 3 months of storage below 27℃; and the viscosity change is <2% when stored at low temperatures of 0~5℃. The resulting homogeneous and stable adhesive material is as follows: Figure 1 As shown. The finished film can be stably stored at -15℃ for ≥3 months, and its processing activity can be restored after being placed at room temperature for 30~60 minutes, exhibiting a wide operating window. The obtained film is as follows. Figure 2 As shown, the adhesive film does not break when bent after thawing and shows no rheological changes. After curing, it has a Shore D hardness of 79~83, tensile strength of 36~38 MPa, Tg of 102~108℃, flame retardancy of UL94V-0, dielectric strength ≥25kV / mm, and thermal conductivity of 0.4~0.5 W / mK. After encapsulation, it can completely encapsulate the chip with a clear outline, no voids or material leakage, no chip detachment during dicing, and no failure in Uhast testing, meeting the precision packaging requirements of semiconductor chips.
[0050] All comparative examples exhibited significant performance defects, rendering them unsuitable for chip packaging applications. Comparative Example 1, due to excessive modified amine curing agent and the absence of dicyandiamide, resulted in complete hardening of the film after semi-curing, making encapsulation impossible. Comparative Example 2, lacking modified amine curing agent and organic urea accelerator, and with excessive dicyandiamide, exhibited extremely poor semi-curing effects, severe rheological changes in the colloid during encapsulation, and unqualified curing results. Comparative Example 3, due to excessively high mixing temperature, caused premature cross-linking of the adhesive, leading to a sharp increase in viscosity, numerous pores after lamination, and unqualified appearance. Comparative Example 4, due to reversed raw material mixing order, resulted in poor filler dispersion, with undispersed powder agglomerates in the film, affecting encapsulation quality. Comparative Example 5, by removing the core filler nano-calcium carbonate and adding excessive amounts of silica, resulted in poor rheological properties of the adhesive, uneven thickness after lamination, and inability to form a film normally. Comparative Example 6, using untreated nano-calcium carbonate, had a high oil absorption value, leading to abnormal adhesive viscosity, numerous pores in the film after lamination, and unqualified appearance and performance.
[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A chip encapsulation film, characterized in that, It comprises the following raw materials in parts by weight: 100 parts epoxy resin, 40-60 parts nano calcium carbonate, 20-40 parts silicon dioxide, 20-40 parts aluminum hydroxide, 10-20 parts nano silicon-based fiber, 5-10 parts modified amine curing agent, 5-10 parts dicyandiamide, and 1-2 parts organic urea accelerator.
2. The encapsulating film for chip packaging according to claim 1, characterized in that, The nano-calcium carbonate particles have a diameter of 20-60 nm and are prepared by surface treatment with borate ester.
3. The encapsulating film for chip packaging according to claim 1, characterized in that, The nano-silicon-based fibers have a diameter of 20-50 nm and a length of 600-1500 nm, and are surface-treated with a silane coupling agent.
4. A method for preparing a chip encapsulation film according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Stir and mix epoxy resin, nano calcium carbonate, silicon dioxide, aluminum hydroxide, and nano silicon-based fibers. S2. Add dicyandiamide and organic urea accelerator and stir to mix; S3. Add modified amine curing agent and stir to mix; S4. The mixed adhesive is applied to the lower release film and then laminated with the upper release film. After being pressed by rollers, baked, and cooled, the adhesive film for chip packaging is obtained.
5. The method for preparing the chip encapsulation film according to claim 4, characterized in that, During steps S1 to S3, the material temperature is controlled to be below 40℃.
6. The method for preparing the chip encapsulation film according to claim 4, characterized in that, After the S4 roller forms the film, it is baked at 80~100℃ for 20~30 min.
7. The encapsulating film for chip packaging according to claim 4, characterized in that, The upper release film has a temperature resistance of not less than 100℃ and a release force of 5~10 g; the lower release film has a temperature resistance of not less than 160℃ and a release force of 100~150 g.
8. The application of the chip encapsulation film according to any one of claims 1 to 4, characterized in that, Used in semiconductor chip packaging.
9. The application of the chip encapsulation film according to claim 8, characterized in that, The process includes the following steps: After the preserved chip encapsulation film is brought to room temperature, the upper release film is peeled off and then attached to the surface of the semiconductor chip; under heating and pressure, the film is stretched to wrap the chip, and after vacuum degassing, the lower release film is peeled off; and then the temperature is raised for curing.
10. The application of the chip encapsulation film according to claim 8, characterized in that, The encapsulating film for the chip is stored below -15℃, and the room temperature recovery time is 30~60 min; it is heated and pressurized at 60~80℃ and 0.05~0.15 MPa. Heat to 140~160℃ for curing.