High-temperature-resistant liquid silicone adhesive for chip packaging and synthesis process of high-temperature-resistant liquid silicone adhesive

Abstract

The invention relates to the technical field of semiconductor materials, and discloses a high-temperature-resistant liquid silicone adhesive for chip packaging and a synthesis process thereof, and the synthesis process comprises the following steps: S1, basic mixing of a component A, S2, intelligent dispersion of a heat-resistant filler of the component A, S3, catalyst addition of the component A, S4, preparation of a component B, and S5, packaging, mixing and curing linkage control. Through algorithm linkage of A component heat-resistant filler dispersion (S2) and packaging, mixing and curing (S5), the initial curing temperature of S5 is calculated according to the final ultrasonic attenuation coefficient alpha of S2, and the temperature rise amplitude (alpha is less than 3.8 and is increased by 8 DEG C when alpha is greater than or equal to 3.8) is dynamically adjusted according to the alpha value, and meanwhile, the S2 ensures that the filler is uniformly dispersed by virtue of an ultrasonic-stirring collaborative algorithm, so that the curing effect of the filler is improved. Finally, after the adhesive is aged at 250 DEG C, the adhesive strength retention rate reaches 82.1%-83.3%, and the long-term high-temperature requirement of a chip is met.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, specifically to a high-temperature resistant liquid silicone adhesive for chip packaging and its synthesis process. Background Technology

[0002] High-temperature resistant liquid silicone adhesive for chip packaging is a type of functional material used for bonding chips to substrates, combining high-temperature resistance and insulation. Its core function is to achieve integrated functions of mechanical fixation, heat conduction and electrical insulation in the long-term high-temperature working environment of chips. It is usually composed of two components, A and B. Component A contains base resin, heat-resistant filler and catalyst, while component B contains crosslinking agent, coupling agent and inhibitor. After the two are mixed and cured, they form a stable adhesive structure. It is a key auxiliary material in the chip packaging industry chain to ensure the reliability of devices.

[0003] In existing technologies, the application process of high-temperature resistant liquid silicone adhesives for chip packaging has formed a mature system: first, components A and B are prepared according to the formula ratio. The preparation of component A requires mixing and dispersing the base resin and heat-resistant filler, and then adding a catalyst; the preparation of component B requires mixing the crosslinking agent and coupling agent, and then adding an inhibitor to adjust the curing speed. In use, components A and B are mixed in proportion, vacuum degassed, and then coated around the chip. Finally, it is cured at 100-160℃ for 1-2 hours. During the curing process, the reaction process is controlled by setting a fixed temperature curve. Related products have been widely used in chip-level packaging scenarios for electronic and semiconductor components.

[0004] The most critical shortcoming of the existing technology is that the dispersion process of the heat-resistant filler component A is independent of the subsequent encapsulation and curing process, and no parameter linkage mechanism has been established. The filler dispersion process is only controlled by a fixed rotation speed and ultrasonic power, and the dispersion effect (such as filler uniformity) is not used as the basis for adjusting the curing process. The curing process adopts a preset fixed temperature program, which cannot dynamically optimize the heating strategy according to the uneven dispersion of the filler in the early stage. This easily leads to incomplete curing in poorly dispersed areas, which ultimately causes fluctuations in the overall high-temperature resistance of the adhesive. After aging at 250℃, the adhesive strength retention rate is difficult to stably meet the standard. In view of this, we propose a high-temperature resistant liquid silicone adhesive for chip encapsulation and its synthesis process. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-temperature resistant liquid silicone adhesive for chip packaging and its synthesis process, which solves the problem that the dispersion process of the heat-resistant filler in component A and the packaging curing process lack parameter linkage, and the curing process relies solely on a fixed temperature program, making it impossible to dynamically adjust based on the initial filler dispersion effect.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-temperature resistant liquid silicone adhesive for chip packaging, comprising component A and component B:

[0007] Component A: Contains 55-75 parts by weight of vinyl-terminated polydimethylsiloxane, with a vinyl content of 0.15-0.45 mmol / g and a viscosity of 800-3500 mPa·s; 12-22 parts by weight of phenyl-vinyl co-modified silicone oil, with a phenyl content of 8-18 wt% and a vinyl content of 0.25-0.55 mmol / g; 6-11 parts by weight of nano-alumina and nano-silica composite filler pretreated with silane coupling agent, with nano-alumina particle size of 25-45 nm and nano-silica particle size of 15-30 nm, in a mass ratio of 2:1 to 1:2; and 0.15-0.45 parts by weight of platinum-divinyltetramethyldisiloxane complex catalyst, with a platinum content of 1000-5000 ppm.

[0008] Component B: Contains 25-38 parts by weight of hydrogen-containing polysiloxane with a hydrogen content of 0.12-0.28 mmol / g and a viscosity of 300-800 mPa·s; 6-9 parts by weight of an interface-modifying coupling agent composed of γ-aminopropyltriethoxysilane and epoxysilane in a mass ratio of 1:1; and 0.02-0.08 parts by weight of a 1-ethynyl-1-cyclohexanol inhibitor.

[0009] Preferably, in the nano-titanium dioxide composite filler that has undergone organic treatment such as nano-alumina and nano-silica, the surface of nano-aluminum nitride is treated with a silane coupling agent to form Si-O-Al bonds, and the surface of nano-silica is treated to form Si-O-Si bonds.

[0010] The synthesis process of a high-temperature resistant liquid silicone adhesive for chip packaging includes the following steps:

[0011] S1.A Basic Mixing Step: In a reaction vessel with nitrogen protection, temperature control and high-speed stirring, add the vinyl-terminated polydimethylsiloxane and phenyl-vinyl co-modified silicone oil as described in claim 1, and stir at 250-350 r / min for 15 min;

[0012] S2.A Component Heat-Resistant Filler Intelligent Dispersion Step: In the mixed system obtained in step S1, add the nano-alumina and nano-silica composite filler pretreated with silane coupling agent as described in claim 1, and use an ultrasonic-stirring coordinated dispersion control algorithm: Real-time acquisition of ultrasonic attenuation coefficient α (dB / cm) and stirring torque τ (N·m); when α < 3.8 and τ > 10, automatically increase the stirring speed to 380-400 r / min and maintain ultrasonic power; when α ≥ 3.8 and τ ≤ 10, maintain the current parameters and continue processing at 90-105℃ for 2.5-3.5 hours, and record the final stable value of α.

[0013] S3. Catalyst addition step for component A: After the system obtained in step S2 is cooled to below 40°C, add the platinum-divinyltetramethyldisiloxane complex catalyst as described in claim 1, and stir at 150-200 r / min for 30 min to obtain component A;

[0014] S4. Preparation steps of component B: In a stirred tank at room temperature, first add the interface-modifying coupling agent of hydrogen-containing polysiloxane, γ-aminopropyltriethoxysilane and epoxysilane as described in claim 1, stir at 200-250 r / min for 20 min, then add the 1-ethynyl-1-cyclohexanol inhibitor as described in claim 1 dropwise, and continue stirring for 1 to 1.5 hours to obtain component B;

[0015] S5. Encapsulation and Curing Linkage Control Step: Mix component A obtained in step S3 with component B obtained in step S4 at a mass ratio of 1.2:1-2:1. After vacuum degassing for 5-8 minutes, coat the mixture onto the bonding surface between the chip and the substrate. Use a curing control algorithm linked to step S2: Based on the final stable value of α in step S2, set the initial curing temperature T0 = 85 + (4.2 - α) × 5℃. Monitor the dielectric constant ε of the curing system in real time. When the rate of decrease of ε is < 0.01 / min, automatically increase the temperature by 5-8℃. The total curing time is controlled within 1.2-1.8 hours.

[0016] Preferably, before step S1, the reactor undergoes a three-stage pretreatment: first, the inner wall is rinsed with anhydrous ethanol for 10-15 minutes, then a vacuum is drawn to -0.095 MPa and maintained for 30 minutes, and finally, nitrogen gas with a purity ≥99.99% is introduced to atmospheric pressure, and the replacement is repeated 3 times.

[0017] Preferably, in step S2, the ultrasonic device uses a frequency-adjustable transducer with an initial frequency of 35 kHz, automatically switching to 45 kHz every 30 minutes and maintaining it for 5 minutes, and the ultrasonic power density is controlled between 0.5 and 0.8 W / cm². 2 The agitator adopts a ribbon structure, and the gap between the blade and the vessel wall is 5-8mm.

[0018] Preferably, in step S2, the dispersion process is sampled once per hour, and the particle size of the filler agglomerates is measured using a laser particle size analyzer. When the difference between two consecutive D90 measurements is ≤20nm, the dispersion is considered stable, and the step can be terminated. The cooling process adopts a gradient cooling mode, reducing the temperature by 5℃ every 10 minutes until it reaches 40℃.

[0019] Preferably, in step S3, the catalyst is pre-diluted with an equal amount of phenyl-vinyl co-modified silicone oil and added dropwise at a uniform rate within 15 minutes using a constant pressure dropping funnel. The stirring paddle is eccentrically installed with an eccentricity of 1 / 5 of the radius of the reactor. The viscosity of the system is recorded every 5 minutes during the stirring process, and the final viscosity is controlled at 1500-2000 mPa·s.

[0020] Preferably, in step S4, the hydrogen-containing polysiloxane is filtered through a 0.22μm organic filter membrane before being added, a baffle made of polytetrafluoroethylene is installed on the inner wall of the stirred tank, the height of the baffle is 2 / 3 of the height of the tank, the stirring shaft speed fluctuation is controlled within ±5r / min, and the final pH value of the mixed system is controlled at 6.5-7.5.

[0021] Preferably, in step S4, the inhibitor is dehydrated by molecular sieve before being added, and nitrogen is used for micro-positive pressure protection during the addition process, with a pressure of 0.02-0.03 MPa. After the addition is completed, stirring is continued for 30 minutes, and then the mixture is allowed to stand and age for another 30 minutes. The obtained component B needs to be used within 2 hours or stored in a sealed refrigerator at 5-10°C.

[0022] Preferably, in step S5, the mixing of components A and B is carried out using a planetary mixer with a revolution speed of 800-1000 r / min and a rotation speed of 200-300 r / min, and a mixing time of 5-8 minutes; the coating is controlled by a precision dispensing valve, with a thickness deviation of ≤±5μm; and the temperature-time curve is recorded in real time during the curing process to ensure that the curve fluctuation range is ≤±3℃.

[0023] This invention provides a high-temperature resistant liquid silicone adhesive for chip packaging and its synthesis process.

[0024] It has the following beneficial effects:

[0025] 1. This invention establishes an algorithmic linkage between the dispersion of the heat-resistant filler in component A (S2) and the encapsulation and curing process (S5). The initial curing temperature of S5 is calculated based on the final ultrasonic attenuation coefficient α of S2, and the curing temperature rise is dynamically adjusted in conjunction with the α value. When α < 3.8 (slightly poor dispersion), the temperature rises by 8℃; when α ≥ 3.8 (good dispersion), the temperature rises by 5℃, avoiding localized poor curing caused by uneven dispersion. Simultaneously, the rotation speed of S2 is adjusted in real time through an ultrasonic-stirring collaborative algorithm to ensure uniform filler dispersion, providing a high-quality matrix for S5 curing. Ultimately, the adhesive strength retention rate after aging at 250℃ reaches 82.1%–83.3%, meeting the long-term high-temperature operation requirements of the chip.

[0026] 2. This invention links the ultrasonic frequency switching algorithm in S2 with the ultrasonic-stirring coordinated dispersion algorithm, periodically switching within the 30-50kHz frequency range (35kHz as the primary frequency and 45kHz as the secondary frequency). This, combined with real-time acquisition of α and τ parameters to adjust the stirring speed, avoids directional agglomeration of the filler caused by a single frequency, while ensuring sufficient dispersion through torque and attenuation coefficient feedback. This linkage results in component A having a D50 ≤ 330nm and a sedimentation rate ≤ 3.5%. Compared to Comparative Example 3 (D50 = 420nm, sedimentation rate 7.8%) controlled by a single algorithm, the dispersion stability is significantly improved, laying the foundation for achieving the required insulation and adhesion performance.

[0027] 3. This invention links the gradient cooling algorithm (S2) with the dispersion stability determination algorithm. It first steadily cools the material to 40°C at a rate of 5°C every 10 minutes to avoid secondary agglomeration of the filler caused by sudden cooling. Simultaneously, it uses hourly D90 difference measurements to determine dispersion stability (termination occurs when the difference is ≤20nm), balancing cooling efficiency and dispersion quality. This linkage forms a closed loop with the S5 curing algorithm, resulting in an adhesive volume resistivity of 2.5 × 10⁻⁶. 14 -2.8×10 14 Ω·cm, compared to Comparative Example 2 (0.9×10) without linkage control 14 (Ω·cm), significantly improving insulation performance and process adaptability. Attached Figure Description

[0028] Figure 1 This is a process diagram for synthesizing a high-temperature resistant liquid silicone adhesive used in chip packaging. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a high-temperature resistant liquid silicone adhesive for chip packaging and its synthesis process, comprising component A and component B:

[0031] Component A: Contains 55-75 parts by weight of vinyl-terminated polydimethylsiloxane, with a vinyl content of 0.15-0.45 mmol / g and a viscosity of 800-3500 mPa·s; 12-22 parts by weight of phenyl-vinyl co-modified silicone oil, with a phenyl content of 8-18 wt% and a vinyl content of 0.25-0.55 mmol / g; 6-11 parts by weight of nano-alumina and nano-silica composite filler pretreated with silane coupling agent, with nano-alumina particle size of 25-45 nm and nano-silica particle size of 15-30 nm, in a mass ratio of 2:1 to 1:2; and 0.15-0.45 parts by weight of platinum-divinyltetramethyldisiloxane complex catalyst, with a platinum content of 1000-5000 ppm.

[0032] Component B: Contains 25-38 parts by weight of hydrogen-containing polysiloxane with a hydrogen content of 0.12-0.28 mmol / g and a viscosity of 300-800 mPa·s; 6-9 parts by weight of an interface-modifying coupling agent composed of γ-aminopropyltriethoxysilane and epoxysilane in a mass ratio of 1:1; and 0.02-0.08 parts by weight of a 1-ethynyl-1-cyclohexanol inhibitor.

[0033] In the nano-titanium dioxide composite filler that has undergone organic treatment such as nano-alumina and nano-silica, the surface of nano-aluminum nitride forms Si-O-Al bonds after treatment with a silane coupling agent, and the surface of nano-silica forms Si-O-Si bonds after treatment.

[0034] Example 1:

[0035] Component A

[0036] Vinyl-terminated polydimethylsiloxane: 60 parts by weight, vinyl content 0.2 mmol / g, viscosity 1800 mPa·s;

[0037] Phenyl-vinyl co-modified silicone oil: 15 parts by weight, phenyl content 10 wt%, vinyl content 0.3 mmol / g;

[0038] Nano-alumina and nano-silica composite filler pretreated with silane coupling agent: 7 parts by weight, nano-alumina particle size 30nm, nano-silica particle size 20nm, and the mass ratio of the two is 1.5:1;

[0039] Platinum-divinyltetramethyldisiloxane complex catalyst: 0.2 parts by weight, platinum content 2500 ppm.

[0040] Component B

[0041] Hydrogen-containing polysiloxane: 30 parts by weight, hydrogen content 0.15 mmol / g, viscosity 500 mPa·s;

[0042] An interface-modifying coupling agent composed of γ-aminopropyltriethoxysilane and epoxysilane in a mass ratio of 1:1: 7 parts by mass;

[0043] 1-Ethynyl-1-cyclohexanol inhibitor: 0.04 parts by weight.

[0044] Example 2:

[0045] Component A

[0046] Vinyl-terminated polydimethylsiloxane (60 parts by weight, vinyl content 0.2 mmol / g, viscosity 1800 mPa·s), nano-alumina and nano-silica composite filler pretreated with silane coupling agent and organically treated (7 parts by weight, nano-alumina particle size 30 nm, nano-silica particle size 20 nm, mass ratio 1.5:1), and platinum-divinyltetramethyldisiloxane complex catalyst (0.2 parts by weight, platinum content 2500 ppm) are all consistent with those in Example 1;

[0047] The phenyl content of the phenyl-vinyl co-modified silicone oil was adjusted to 15 wt% (in the range of 8-18 wt%), and the other parameters (15 parts by mass, vinyl content 0.3 mmol / g) were consistent with those in Example 1.

[0048] Component B

[0049] All components and parameters (30 parts by weight of hydrogen-containing polysiloxane, hydrogen content 0.15 mmol / g, viscosity 500 mPa·s; 7 parts by weight of interface-modifying coupling agent; 0.04 parts by weight of inhibitor) are completely consistent with those in Example 1.

[0050] Example 3:

[0051] Component A

[0052] Vinyl-terminated polydimethylsiloxane (60 parts by weight, vinyl content 0.2 mmol / g, viscosity 1800 mPa·s), phenyl-vinyl co-modified silicone oil (15 parts by weight, phenyl content 10 wt%, vinyl content 0.3 mmol / g), and platinum-divinyltetramethyldisiloxane complex catalyst (0.2 parts by weight, platinum content 2500 ppm) were all consistent with those in Example 1.

[0053] The mass ratio of nano-aluminum nitride to nano-silica was adjusted to 2.0:1 (within the range of 2:1 to 1:2), and the other parameters (7 parts by mass, nano-aluminum nitride particle size 30nm, nano-silica particle size 20nm, pretreated with silane coupling agent) were consistent with those in Example 1.

[0054] Component B

[0055] All components and parameters (30 parts by weight of hydrogen-containing polysiloxane, hydrogen content 0.15 mmol / g, viscosity 500 mPa·s; 7 parts by weight of interface-modifying coupling agent; 0.04 parts by weight of inhibitor) are completely consistent with those in Example 1.

[0056] Comparative Example 1:

[0057] Component A

[0058] The nano-titanium dioxide composite filler (7 parts by weight, nano-alumina particle size 30nm, nano-silica particle size 20nm, mass ratio 1.5:1) and platinum-divinyltetramethyldisiloxane complex catalyst (0.2 parts by weight, platinum content 2500ppm) pretreated with silane coupling agent and organically treated with nano-alumina and nano-silica are consistent with those in Example 1.

[0059] The phenyl-vinyl co-modified silicone oil was removed, and the mass fraction of vinyl-terminated polydimethylsiloxane was adjusted to 75 parts by mass (ensuring that the total mass of component A remained unchanged). The remaining parameters (vinyl content 0.2 mmol / g, viscosity 1800 mPa·s) were consistent with those in Example 1.

[0060] Component B

[0061] All components and parameters (30 parts by weight of hydrogen-containing polysiloxane, hydrogen content 0.15 mmol / g, viscosity 500 mPa·s; 7 parts by weight of interface-modifying coupling agent; 0.04 parts by weight of inhibitor) are completely consistent with those in Example 1.

[0062] Comparative Example 2:

[0063] Component A

[0064] Vinyl-terminated polydimethylsiloxane (60 parts by weight, vinyl content 0.2 mmol / g, viscosity 1800 mPa·s), phenyl-vinyl co-modified silicone oil (15 parts by weight, phenyl content 10 wt%, vinyl content 0.3 mmol / g), and platinum-divinyltetramethyldisiloxane complex catalyst (0.2 parts by weight, platinum content 2500 ppm) were all consistent with those in Example 1.

[0065] The nano-titanium dioxide composite filler, which is organically treated with nano-alumina and nano-silica, was not pretreated with silane coupling agent (so it could not form Si-O-Al and Si-O-Si bonds). The other parameters (7 parts by mass, nano-aluminum nitride particle size 30nm, nano-silica particle size 20nm, mass ratio 1.5:1) were the same as in Example 1.

[0066] Component B

[0067] All components and parameters (30 parts by weight of hydrogen-containing polysiloxane, hydrogen content 0.15 mmol / g, viscosity 500 mPa·s; 7 parts by weight of interface-modifying coupling agent; 0.04 parts by weight of inhibitor) are completely consistent with those in Example 1.

[0068] Comparative Example 3:

[0069] Component A

[0070] Vinyl-terminated polydimethylsiloxane (60 parts by weight, vinyl content 0.2 mmol / g, viscosity 1800 mPa·s), phenyl-vinyl co-modified silicone oil (15 parts by weight, phenyl content 10 wt%, vinyl content 0.3 mmol / g), and platinum-divinyltetramethyldisiloxane complex catalyst (0.2 parts by weight, platinum content 2500 ppm) were all consistent with those in Example 1;

[0071] The organically treated nano-alumina and nano-titanium dioxide composite fillers, such as nano-alumina and nano-silica, were replaced with a single nano-alumina filler (7 parts by weight, 30 nm particle size, pretreated with silane coupling agent). The remaining parameters were the same as in Example 1.

[0072] Component B

[0073] All components and parameters (30 parts by weight of hydrogen-containing polysiloxane, hydrogen content 0.15 mmol / g, viscosity 500 mPa·s; 7 parts by weight of interface-modifying coupling agent; 0.04 parts by weight of inhibitor) are completely consistent with those in Example 1.

[0074] Establish the following experiment:

[0075] (I) Experimental Objective

[0076] The effects of different component formulations (Examples 1-3 and Comparative Examples 1-3) on the high-temperature resistance, bond strength, insulation performance and dispersion stability of the adhesive were verified, and the optimal formulation that meets the chip packaging requirements was screened.

[0077] (II) Performance Testing Items and Methods

[0078] 1. High temperature resistance test (250℃ constant temperature aging test)

[0079] Test standard: Refer to GB / T7141-2022 "Test Method for Thermal Aging of Plastics";

[0080] Sample preparation: Place the cured adhesive sample (size: 20mm×20mm×2mm) in a high-temperature aging chamber;

[0081] Experimental parameters: Set temperature 250℃, constant temperature aging for 500h, take out samples every 100h, cool to room temperature and test appearance (whether cracked or discolored) and adhesion strength retention rate.

[0082] Judgment criteria: No cracking or discoloration after aging, and a bond strength retention rate of ≥80% are considered qualified.

[0083] 2. Bond strength test (shear bond strength)

[0084] Test basis: Refer to GB / T13936-2014 "Determination of Shear Strength of Bonds between Vulcanized Rubber and Metal";

[0085] Sample preparation: A composite structure of "sapphire substrate (simulating LED chip) - adhesive - alumina ceramic substrate (simulating packaging substrate)" was adopted. The adhesive was coated around the chip and blocked the light emission from the chip's perimeter, with a thickness of 50μm.

[0086] Experimental parameters: Using a universal testing machine with a loading rate of 5 mm / min, the shear bond strength of samples aged at room temperature (25℃) and 250℃ was tested. Each formulation was tested 3 times, and the average value was taken.

[0087] Judgment criteria: The shear bond strength at room temperature is ≥2.5MPa, and after aging it is ≥2.0MPa to be considered qualified.

[0088] 3. Volume resistivity test (insulation performance)

[0089] Test basis: Refer to GB / T1410-2006 "Test methods for volume resistivity and surface resistivity of solid insulating materials";

[0090] Sample preparation: The size of the cured adhesive sample is 50mm×50mm×1mm, and the surface is clean and free of impurities;

[0091] Experimental parameters: A high resistivity meter was used, a voltage of 500V was applied, and the sample was kept at a constant temperature of 25℃ and a relative humidity of 50% for 1 minute. The volume resistivity value was then read. Each sample was tested 3 times and the average value was taken.

[0092] Judgment criterion: Volume resistivity ≥ 1×10 14 Ω·cm is acceptable (meets chip insulation requirements).

[0093] 4. Dispersion stability test (particle size distribution and sedimentation rate)

[0094] Test basis: Refer to GB / T19077-2016 "Particle size analysis by laser diffraction";

[0095] Sample preparation: Take 5 mL of the uncured A component mixture, dilute it to 100 mL with anhydrous ethanol, and ultrasonically disperse for 10 min;

[0096] Experimental parameters: D50 (median particle size) and D90 (90% particle size) were measured using a laser particle size analyzer. Component A was placed in a sealed container and left to stand at room temperature for 72 hours. The sedimentation rate (mass of sediment / total mass of filler × 100%) was then measured.

[0097] Judgment criteria: D50≤500nm, D90≤800nm, and sedimentation rate≤5% are acceptable (to avoid uneven local performance after curing).

[0098] Performance test parameter table:

[0099] Table 1: High Temperature Resistance Test Parameters and Results

[0100]

[0101] Table 2: Shear bond strength test parameters and results:

[0102]

[0103]

[0104] Table 3: Volume Resistivity Test Parameters and Results

[0105]

[0106]

[0107] Table 4. Dispersion Stability Test Parameters and Results

[0108]

[0109] Experimental conclusions

[0110] I. Summary of Core Performance Standards

[0111] Through testing the high temperature resistance, bonding strength, insulation performance, and dispersion stability of Examples 1-3 (optimized formulation with controlled variables) and Comparative Examples 1-3 (deviating from the core technical solution), the results show that all performance indicators of Examples 1-3 meet the requirements of chip packaging adhesives. Comparative Examples 1-3, due to the lack of key components or process steps, have at least one core performance that does not meet the standard. The specific differences and reasons are analyzed as follows.

[0112] II. Key Influencing Factors and Performance Correlation Conclusions

[0113] (I) Phenyl-vinyl co-modified silicone oil is the core guarantee of high temperature resistance and adhesive strength.

[0114] Comparing Examples 1-3 (containing 15 parts by weight of phenyl-vinyl co-modified silicone oil) with Comparative Example 1 (this component was removed), it can be seen that:

[0115] After aging at 250℃ for 500 hours, Examples 1-3 showed a bond strength retention rate of 82.1% to 83.3%, with no cracking or discoloration, and a reflectivity of over 98%. In contrast, Comparative Example 1 showed a bond strength retention rate of only 68.2% after aging, with slight cracking and yellowing, and its room temperature bond strength (2.2 MPa) did not meet the qualified standard of ≥2.5 MPa.

[0116] Conclusion: The phenyl structure in phenyl-vinyl co-modified silicone oil can improve the high-temperature stability of the organosilicon matrix, while the vinyl structure can synergistically crosslink with other components of component A to enhance interfacial bonding. Without this component, the heat aging resistance and adhesion performance of the adhesive are significantly reduced, failing to meet the long-term high-temperature operation requirements of the chip.

[0117] (II) The silane coupling agent pretreatment of nanocomposite fillers determines the dispersion stability and insulation performance.

[0118] Comparing Examples 1-3 (composite fillers pretreated with silane coupling agent) with Comparative Example 2 (untreated), it can be seen that:

[0119] In Examples 1-3, component A had a D50 ≤ 330 nm and a D90 ≤ 700 nm. After standing for 72 hours, the sedimentation rate was only 3.0%–3.5%, and the volume resistivity reached 2.5 × 10⁻⁶. 14 -2.8×10 14 Ω·cm; Comparative Example 2 has a D50 of 650 nm, a D90 of 980 nm, a sedimentation rate of 12.5%, and a volume resistivity of only 0.9 × 10⁻⁶ Ω·cm; 14 Ω·cm (not meeting the standard of ≥1×10¹⁴Ω·cm).

[0120] Conclusion: Silane coupling agent pretreatment can form Si-O-Al bonds on the surface of nano-aluminum nitride and Si-O-Si bonds on the surface of nano-silica, significantly improving the compatibility between the filler and the organosilicon matrix, preventing agglomeration. When the adhesive is coated around the chip, it blocks light from emanating from the chip's periphery, while the white part can reflect some light well with a reflectivity of over 98%. Without pretreatment, the filler is prone to agglomeration and sedimentation, which not only leads to poor dispersion stability but also damages the insulation structure, causing a decrease in volume resistivity and failing to meet the chip insulation requirements.

[0121] (III) Nanocomposite fillers (aluminum nitride + silicon dioxide) are superior to single aluminum nitride fillers.

[0122] Comparing Examples 1-3 (composite packing) with Comparative Example 3 (single aluminum nitride packing), it can be seen that:

[0123] After aging, the bond strength retention rate of Examples 1-3 was 82.1% to 83.3%, and the settlement rate was 3.0% to 3.5%; after aging, the bond strength retention rate of Comparative Example 3 was 69.6%, and the settlement rate was 7.8% (exceeding the 5% acceptable standard).

[0124] Conclusion: The addition of nano-silica can optimize the particle size distribution of fillers, reduce the packing gap of single aluminum nitride fillers, and improve the dispersion uniformity and interfacial bonding tightness. Single aluminum nitride fillers are prone to agglomeration due to their uniform particle size distribution, which reduces dispersion stability and weakens interfacial adhesion resistance at high temperatures, and cannot match the comprehensive performance of composite fillers.

[0125] (iv) Optimization trend of internal variables in the implementation example on performance

[0126] In Examples 1-3, the test results for controlling a single variable (phenyl content, composite filler mass ratio) showed that:

[0127] Increased phenyl content (Example 1: 10wt% → Example 2: 15wt%): room temperature bond strength increased from 2.8MPa to 3.0MPa, and retention rate after aging increased from 82.1% to 83.3%, indicating that within the range of 8-18wt%, appropriately increasing the phenyl content can further enhance high temperature resistance and bond strength;

[0128] Adjustment of composite packing mass ratio (Example 1:1.5:1 → Example 3:2.0:1): Volume resistivity from 2.5×10 14 Ω·cm increased to 2.6×10 14 The sedimentation rate increased from 3.2% to 3.5% in Ω·cm, with no significant fluctuation in performance, indicating that within the range of 2:1 to 1:2, this ratio has little impact on core performance and the formulation has high tolerance for error.

[0129] Please see the appendix Figure 1 The synthesis process of a high-temperature resistant liquid silicone adhesive for chip packaging includes the following steps:

[0130] S1.A Basic Mixing Step: In a reaction vessel with nitrogen protection, temperature control and high-speed stirring, add the vinyl-terminated polydimethylsiloxane and phenyl-vinyl co-modified silicone oil as described in claim 1, and stir at 250-350 r / min for 15 min;

[0131] Before step S1, the reactor undergoes a three-stage pretreatment: first, the inner wall is rinsed with anhydrous ethanol for 10-15 minutes, then a vacuum is drawn to -0.095 MPa and maintained for 30 minutes, and finally, nitrogen gas with a purity ≥99.99% is introduced to atmospheric pressure, and the replacement is repeated 3 times.

[0132] S2. A Component Heat-Resistant Filler Intelligent Dispersion Step: In the mixed system obtained in step S1, add the nano-alumina and nano-silica composite filler pretreated with silane coupling agent as described in claim 1, and use an ultrasonic-stirring coordinated dispersion control algorithm: Real-time acquisition of ultrasonic attenuation coefficient α (dB / cm) and stirring torque τ (N·m); when α < 3.8 and τ > 10, automatically increase the stirring speed to 380-400 r / min and maintain ultrasonic power; when α ≥ 3.8 and τ ≤ 10, maintain the current parameters and continue processing at 90-105℃ for 2.5-3.5 hours, and record the final stable value of α, including the following algorithm:

[0133] Step 1: First, initialize the parameters and set the initial ultrasonic power density P0 (unit: W / cm²). 2 The values ​​range from 0.5 to 0.8, representing the initial ultrasonic energy intensity applied to the system; the initial stirring speed N0 (unit: r / min, value: 250-350, representing the initial rotational speed of the stirring device); and the target processing temperature T. set (Unit: °C, values ​​90-105, representing the constant temperature to be maintained during dispersion), then the temperature control system of the reactor is activated to stabilize the system temperature at T. set The corresponding values ​​are then added to the mixed system obtained in step S1, along with the nano-alumina and nano-silica composite filler pretreated with silane coupling agent, to complete the initial preparation work.

[0134] Step 2: Conduct real-time parameter acquisition. The ultrasonic attenuation coefficient α (unit: dB / cm, reflecting the degree of attenuation of ultrasound propagation in the system; the smaller the attenuation value, the more uniform the packing dispersion) of the current system is acquired through the ultrasonic monitoring module. The real-time stirring torque τ (unit: N·m, reflecting the resistance of the system to the stirring shaft during the stirring process; the larger the resistance value, the more serious the packing agglomeration) of the stirring shaft is acquired through the torque sensor. The acquisition frequency is set to 1 time / 30s to ensure that changes in the dispersion state of the system are captured in real time.

[0135] Step 3: Perform conditional judgment and parameter adjustment, substituting the collected α and τ into the judgment formula.

[0136]

[0137] Where α0 = 3.8 dB / cm is the preset ultrasonic attenuation coefficient threshold; a value lower than this indicates insufficient packing dispersion. τ0 = 10 N·m is the preset stirring torque threshold; a value higher than this indicates severe packing agglomeration. currentGiven the current stirring speed (unit: r / min), if α < α0 and τ > τ0, then increase the stirring speed to 380-400 r / min and keep the ultrasonic power P0 unchanged. If the condition is not met, then maintain the current stirring speed and ultrasonic power.

[0138] Step 4: Initialize the frequency parameters, setting the initial ultrasonic frequency f0 = 35kHz (unit: kHz, representing the initial ultrasonic vibration frequency applied by the ultrasonic device), the frequency switching interval Δt = 30min (unit: min, representing the time interval between two frequency switching), and the frequency hold time t after switching. hold =5min (unit: min, representing the time required to maintain after switching to the target frequency), then start the ultrasound device to stabilize the initial frequency at the value corresponding to f0;

[0139] Step 5: Implement time-series monitoring. Collect the current ultrasonic working time t (unit: min, starting from the start time of the ultrasonic device) in real time through a timer. Calculate the remainder of t and Δt, tmodΔt, where "mod" is the remainder operation. The calculation result represents the time difference between the current time and the last frequency switch. Use this result to determine whether the frequency switch node has been reached.

[0140] Step 6: Execute frequency switching control, and control frequency switching according to the formula based on timing monitoring results:

[0141]

[0142] Where k = 1, 2, 3, ... are positive integers, representing the k-th frequency switching period, f1 = 45 kHz is the target ultrasonic frequency after switching, and when t is in the range [kΔt, kΔt+t]... hold When t is in the range, the ultrasound frequency is switched to f1 = 45kHz. When t exceeds this range, it is restored to the initial frequency f0 = 35kHz.

[0143] Step 7: Perform continuous monitoring and recording, repeating steps 2-3 until the system reaches T. set The cumulative processing time t reaches t total (Unit: h, value 2.5-3.5, representing the total time requirement for the dispersed steps), during which the average values ​​of α and τ are recorded every 10 minutes, and finally when t = t total At this point, record the stable ultrasonic attenuation coefficient α. final (Unit: dB / cm, used as a linkage parameter for subsequent encapsulation, mixing, and curing steps), the steps corresponding to this algorithm are now complete;

[0144] In step S2, the ultrasonic device uses a frequency-adjustable transducer with an initial frequency of 35kHz, automatically switching to 45kHz every 30 minutes and maintaining it for 5 minutes, and the ultrasonic power density is controlled between 0.5 and 0.8 W / cm². 2 The stirring paddle adopts a ribbon structure, and the gap between the paddle blade and the vessel wall is 5-8mm;

[0145] In step S2, the dispersion process is sampled once per hour, and the particle size of the filler agglomerates is measured using a laser particle size analyzer. When the difference between two consecutive D90 measurements is ≤20nm, the dispersion is considered stable, and this step can be terminated. The cooling process adopts a gradient cooling mode, reducing the temperature by 5℃ every 10 minutes until it reaches 40℃.

[0146] S3. Catalyst addition step for component A: After the system obtained in step S2 is cooled to below 40°C, add the platinum-divinyltetramethyldisiloxane complex catalyst as described in claim 1, and stir at 150-200 r / min for 30 min to obtain component A;

[0147] In step S3, the catalyst is pre-diluted with an equal amount of phenyl-vinyl co-modified silicone oil and added dropwise at a uniform rate within 15 minutes using a constant pressure dropping funnel. The stirring paddle is eccentrically installed with an eccentricity of 1 / 5 of the radius of the reactor. The viscosity of the system is recorded every 5 minutes during the stirring process, and the final viscosity is controlled at 1500-2000 mPa·s.

[0148] S4. Preparation steps of component B: In a stirred tank at room temperature, first add the interface-modifying coupling agent of hydrogen-containing polysiloxane, γ-aminopropyltriethoxysilane and epoxysilane as described in claim 1, stir at 200-250 r / min for 20 min, then add the 1-ethynyl-1-cyclohexanol inhibitor as described in claim 1 dropwise, and continue stirring for 1 to 1.5 hours to obtain component B;

[0149] In step S4, the hydrogen-containing polysiloxane is filtered through a 0.22μm organic filter membrane before being added. A baffle made of polytetrafluoroethylene is installed on the inner wall of the stirred tank, with the height of the baffle being 2 / 3 of the height of the tank. The stirring shaft speed fluctuation is controlled within ±5r / min, and the final pH value of the mixed system is controlled between 6.5 and 7.5.

[0150] In step S4, the inhibitor is dehydrated by molecular sieve before being added. During the addition process, nitrogen is used for micro-positive pressure protection, with a pressure of 0.02-0.03 MPa. After the addition is completed, stirring is continued for 30 minutes, followed by standing and aging for another 30 minutes. The obtained component B needs to be used within 2 hours or stored in a sealed refrigerator at 5-10℃.

[0151] S5. Encapsulation and Curing Linkage Control Step: Mix component A obtained in step S3 with component B obtained in step S4 at a mass ratio of 1.2:1-2:1. After vacuum degassing for 5-8 minutes, coat the mixture onto the bonding surface between the chip and the substrate. Use a curing control algorithm linked to step S2: Based on the final stable value of α in step S2, set the initial curing temperature T0 = 85 + (4.2 - α) × 5℃. Monitor the dielectric constant ε of the curing system in real time. When the rate of decrease of ε is < 0.01 / min, automatically increase the temperature by 5-8℃. The total curing time is controlled within 1.2-1.8 hours, including the following algorithm:

[0152] First, extract the final stable value α of the ultrasonic attenuation coefficient (unit: dB / cm, which is the core indicator of the uniformity of filler dispersion after ultrasonic-stirring synergistic dispersion in S2. The larger α is, the more fully the nano-titanium dioxide composite filler with organic treatment such as nano-alumina and nano-silica is dispersed) from the recorded data in step S2. Substitute this value as a linkage parameter into the initial curing temperature calculation formula T0=85+(4.2-α)×5, where T0 is the initial curing temperature in step S5 (unit: ℃, which determines the starting rate of the curing reaction), 85 is the curing temperature benchmark value (unit: ℃, which is the basic curing temperature of components A and B when the filler dispersion is qualified), 4.2 is the target benchmark value of the ultrasonic attenuation coefficient in S2 (unit: dB / cm, corresponding to the ideal α value when the filler is completely dispersed), and 5 is the temperature compensation coefficient (unit: ℃ / (dB / cm), used to adjust T0 according to the dispersion deviation in S2).

[0153] For example, when α = 3.8, T0 = 85 + (4.2 - 3.8) × 5 = 87). After calculating T0, set the upper limit t for the total time of the curing process. total =1.2-1.8h (unit: h, to ensure a balance between curing efficiency and product performance), and at the same time prepare planetary mixing equipment and precision dispensing valve, and complete parameter initialization;

[0154] 2. Combine component A obtained in step S3 with component B obtained in step S4 at a mass ratio m A :m B =1.2:1-2:1(m A For the mass of component A, m B (For component B, this ratio ensures a matching molar ratio of vinyl to hydrogen groups in the hydrosilylation reaction, avoiding incomplete curing or excessive crosslinking.) Add the component to a planetary mixer, start the mixer, and set the revolution speed N. rev =800-1000 r / min (unit: r / min, providing overall hybrid power to prevent component stratification), rotation speed N rot =200-300 r / min (unit: r / min, generates local shear force, promotes molecular-level mixing of components A and B), stirring time tmix =5-8min (unit: min; too short a time may lead to uneven mixing, too long a time may cause premature curing). During the mixing process, observe the system status in real time to ensure that there are no obvious air bubbles or particle agglomeration. After mixing, a uniform adhesive system is obtained.

[0155] 3. Start the dielectric constant monitor and set the monitoring frequency to 1 time / 5min (i.e., the monitoring time interval Δt). mon =t2-t1=5min, where t1 and t2 are the time points of two consecutive monitoring sessions (unit: min; high-frequency monitoring can capture changes in the curing reaction state in a timely manner). The dielectric constant ε at time t1 is recorded respectively. t1 (Unitless, representing the relative permittivity of the cured system, reflecting the degree of polarization of the system; ε is larger in the liquid state and decreases after curing due to increased cross-linking) and the permittivity ε at time t2. t2 (Unitless, test benchmark and ε) t1 (Consistent), substituting into the formula for calculating the rate of decrease of the dielectric constant:

[0156]

[0157] in The rate of decrease of dielectric constant (unit: min) -1 A higher rate indicates a more vigorous curing reaction, while a lower rate indicates a slower reaction. For example, when t1 = 10 min, ε t1 =3.5, t2=15min when ε t2 =3.45, then (The negative sign indicates that ε decreases; in practical applications, the absolute value is used to determine the rate of increase.)

[0158] The calculation obtained in step three Compared to the preset threshold of 0.01 min -1 In comparison, and in conjunction with the α value in S2, the curing temperature is adjusted according to the temperature control decision formula:

[0159]

[0160] Where T n+1 For the adjusted target temperature, T n The current temperature before adjustment (unit: °C) is 3.8, which is the acceptable threshold for the ultrasonic attenuation coefficient in S2 (unit: dB / cm, α≥3.8 represents acceptable S2 dispersion, α<3.8 represents slightly poor dispersion). For example... And when α = 3.6 (< 3.8):

[0161] T n+1 =T n +8ζ

[0162] The reaction lag caused by insufficient dispersion is compensated by increasing the temperature rise; steps 4-5 are repeated continuously, with the temperature adjusted in real time, until the cumulative curing time reaches t. total = 1.2-1.8h, and the dielectric constant ε is stable (difference between two consecutive monitoring values ​​|ε) t3 -ε t2 If |≤0.02), stop heating to complete the encapsulation, mixing, and curing process;

[0163] In step S5, components A and B are mixed using a planetary mixer with a revolution speed of 800-1000 r / min and a rotation speed of 200-300 r / min, and a mixing time of 5-8 minutes. The coating is controlled by a precision dispensing valve, with a thickness deviation of ≤±5μm. The temperature-time curve is recorded in real time during the curing process to ensure that the curve fluctuation range is ≤±3℃.

[0164] 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 high-temperature resistant liquid silicone adhesive for chip packaging, characterized in that, Includes component A and component B: Component A: Contains 55-75 parts by weight of vinyl-terminated polydimethylsiloxane, with a vinyl content of 0.15-0.45 mmol / g and a viscosity of 800-3500 mPa·s; 12-22 parts by weight of phenyl-vinyl co-modified silicone oil, with a phenyl content of 8-18 wt% and a vinyl content of 0.25-0.55 mmol / g; 6-11 parts by weight of nano-alumina and nano-silica composite filler pretreated with silane coupling agent, with nano-alumina particle size of 25-45 nm and nano-silica particle size of 15-30 nm, in a mass ratio of 2:1 to 1:2; and 0.15-0.45 parts by weight of platinum-divinyltetramethyldisiloxane complex catalyst, with a platinum content of 1000-5000 ppm. Component B: contains 25-38 parts by weight of hydrogen-containing polysiloxane with a hydrogen content of 0.12-0.28 mmol / g and a viscosity of 300-800 mPa·s; and 6-9 parts by weight of an interface-modifying coupling agent composed of γ-aminopropyltriethoxysilane and epoxysilane in a mass ratio of 1:

1. 0.02-0.08 parts by weight of 1-ethynyl-1-cyclohexanol inhibitor.

2. The high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In the nano-titanium dioxide composite filler that has undergone organic treatment such as nano-alumina and nano-silica, the surface of nano-aluminum nitride forms Si-O-Al bonds after treatment with a silane coupling agent, and the surface of nano-silica forms Si-O-Si bonds after treatment.

3. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, Includes the following steps: S1.A Basic Mixing Step: In a reaction vessel with nitrogen protection, temperature control and high-speed stirring, add the vinyl-terminated polydimethylsiloxane and phenyl-vinyl co-modified silicone oil as described in claim 1, and stir at 250-350 r / min for 15 min; S2.A Component Heat-Resistant Filler Intelligent Dispersion Step: In the mixed system obtained in step S1, add the nano-alumina and nano-silica composite filler pretreated with silane coupling agent as described in claim 1, and use an ultrasonic-stirring coordinated dispersion control algorithm: Real-time acquisition of ultrasonic attenuation coefficient α (dB / cm) and stirring torque τ (N·m); when α < 3.8 and τ > 10, automatically increase the stirring speed to 380-400 r / min and maintain ultrasonic power; when α ≥ 3.8 and τ ≤ 10, maintain the current parameters and continue processing at 90-105℃ for 2.5-3.5 hours, and record the final stable value of α. S3. Catalyst addition step for component A: After the system obtained in step S2 is cooled to below 40°C, add the platinum-divinyltetramethyldisiloxane complex catalyst as described in claim 1, and stir at 150-200 r / min for 30 min to obtain component A; S4. Preparation steps of component B: In a stirred tank at room temperature, first add the interface-modifying coupling agent of hydrogen-containing polysiloxane, γ-aminopropyltriethoxysilane and epoxysilane as described in claim 1, stir at 200-250 r / min for 20 min, then add the 1-ethynyl-1-cyclohexanol inhibitor as described in claim 1 dropwise, and continue stirring for 1 to 1.5 hours to obtain component B; S5. Encapsulation and Curing Linkage Control Step: Mix component A obtained in step S3 with component B obtained in step S4 at a mass ratio of 1.2:1-2:

1. After vacuum degassing for 5-8 minutes, coat the mixture onto the bonding surface between the chip and the substrate. Use a curing control algorithm linked to step S2: Based on the final stable value of α in step S2, set the initial curing temperature T0 = 85 + (4.2 - α) × 5℃. Monitor the dielectric constant ε of the curing system in real time. When the rate of decrease of ε is < 0.01 / min, automatically increase the temperature by 5-8℃. The total curing time is controlled within 1.2-1.8 hours.

4. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, Before step S1, the reactor undergoes a three-stage pretreatment: first, the inner wall is rinsed with anhydrous ethanol for 10-15 minutes, then a vacuum is drawn to -0.095 MPa and maintained for 30 minutes, and finally, nitrogen gas with a purity ≥99.99% is introduced to atmospheric pressure, and the replacement is repeated 3 times.

5. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In step S2, the ultrasonic device uses a frequency-adjustable transducer with an initial frequency of 35kHz, automatically switching to 45kHz every 30 minutes and maintaining it for 5 minutes, and the ultrasonic power density is controlled between 0.5 and 0.8 W / cm². 2 The agitator adopts a ribbon structure, and the gap between the blade and the vessel wall is 5-8mm.

6. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In step S2, the dispersion process is sampled once per hour, and the particle size of the filler agglomerates is measured using a laser particle size analyzer. When the difference between two consecutive D90 measurements is ≤20nm, the dispersion is considered stable, and the step can be terminated. The cooling process adopts a gradient cooling mode, reducing the temperature by 5℃ every 10 minutes until it reaches 40℃.

7. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In step S3, the catalyst is pre-diluted with an equal amount of phenyl-vinyl co-modified silicone oil and added dropwise at a constant pressure within 15 minutes using a constant pressure dropping funnel. The stirring paddle is installed eccentrically with an eccentricity of 1 / 5 of the radius of the reactor. The viscosity of the system is recorded every 5 minutes during the stirring process, and the final viscosity is controlled at 1500-2000 mPa·s.

8. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In step S4, the hydrogen-containing polysiloxane is filtered through a 0.22μm organic filter membrane before being added. A baffle made of polytetrafluoroethylene is installed on the inner wall of the stirred tank, with the height of the baffle being 2 / 3 of the height of the tank. The stirring shaft speed fluctuation is controlled within ±5r / min, and the final pH value of the mixed system is controlled between 6.5 and 7.

5.

9. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In step S4, the inhibitor is dehydrated by molecular sieve before being added. During the addition process, nitrogen is used for micro-positive pressure protection, with a pressure of 0.02-0.03 MPa. After the addition is completed, stirring is continued for 30 minutes, followed by standing and aging for another 30 minutes. The obtained component B needs to be used within 2 hours or stored in a sealed refrigerator at 5-10℃.

10. The synthesis process of the high-temperature resistant liquid silicone adhesive for chip packaging according to claim 1, characterized in that, In step S5, components A and B are mixed using a planetary mixer with a revolution speed of 800-1000 r / min and a rotation speed of 200-300 r / min, and a mixing time of 5-8 minutes. The coating is controlled by a precision dispensing valve, with a thickness deviation of ≤±5μm. The temperature-time curve is recorded in real time during the curing process to ensure that the curve fluctuation range is ≤±3℃.

Images