Self-repairing material for electronic device packaging and preparation method and packaging method thereof

Abstract

The invention discloses a self-repairing material for electronic device packaging and a preparation method and a packaging method thereof, and belongs to the technical field of electronic device packaging. The self-repairing material comprises the following components: a dynamic reversible chemical bond network formed by a DA bond prepolymer and a hydrogen bond donor in a synergistic manner, boron nitride nanosheets and carbon quantum dots, adding boron nitride nanosheets and carbon quantum dots into the DA bond prepolymer, and fully dispersing; then adding a hydrogen bond donor, and fully stirring to obtain a self-repairing material; spraying a self-repairing material on the surface of the substrate to form a thick packaging layer, curing to form a three-dimensional interpenetrating network structure, and packaging the electronic device; according to the invention, the packaging layer has a rapid self-repairing capability and supports efficient repair; the material has high thermal conductivity, mechanical strength and thermal expansion matching with an LED chip; the self-repairing process does not need high temperature or complex equipment, and is compatible with the existing packaging production line.

Description

Technical Field

[0001] This invention belongs to the field of electronic device packaging technology, specifically to self-healing materials for electronic device packaging, their preparation methods and packaging methods, particularly for Mini / Micro LED packaging processes. Background Technology

[0002] Mini / Micro LED is a miniaturization technology of light-emitting diodes (LEDs). Its core is a semiconductor device that converts electrical energy into light energy through a PN junction structure. Mini LED chips are between 100-300 micrometers in size and use packaging forms such as SMD and COB, and are considered an upgraded version of traditional LEDs. Micro LED chips are less than 50 micrometers in size and require mass transfer technology for integration, making them more advanced semiconductor display devices.

[0003] Mini / Micro LED, as a new generation of display technology, has advantages such as high brightness, high contrast and long lifespan, but its packaging process faces the following technical challenges: 1. Irreversible damage to encapsulation materials: Traditional epoxy resin or silicone encapsulation materials are prone to microcracks when subjected to mechanical or thermal stress, leading to device failure.

[0004] 2. Difficult to repair: After the failed chip is removed, the encapsulation layer is difficult to repair. It needs to be recoated with materials and cured, which is a complex and costly process.

[0005] 3. Insufficient thermal stability: The high power density of Mini / Micro LEDs places higher demands on the high temperature resistance and thermal conductivity of the packaging materials.

[0006] In existing technologies, self-healing materials have been applied in other fields (such as coatings and elastomers), but their adaptability in the semiconductor packaging field is insufficient, for example: 1. The self-healing temperature does not match the LED chip's temperature tolerance. 2. The thermal conductivity and mechanical strength of self-healing materials cannot meet the requirements of high-density packaging; 3. The repair efficiency of dynamic chemical bonds is insufficient to support industrialized rework processes. Summary of the Invention

[0007] This invention overcomes the shortcomings of existing technologies and proposes a self-healing material for electronic device packaging, its preparation method, and its packaging method. This invention is achieved through the following technical solution: Self-healing materials used for electronic device packaging include the following components: A dynamic, reversible chemical bond network formed by the synergistic interaction of DA bond prepolymers and hydrogen bond donors; Boron nitride nanosheets with a mass fraction of 5-15%, wherein the boron nitride nanosheets are surface-modified with a silane coupling agent; Near-infrared absorbing carbon quantum dots with a mass fraction of 0.1-1%.

[0008] Preferably, the DA bond prepolymer is formed by reacting an epoxy resin containing furan groups with a maleimide compound at a molar ratio of 1:0.8-1.2; the hydrogen bond donor is a polyurethane segment containing urea bonds or urethane groups.

[0009] The glass transition temperature (Tg) of the DA bond prepolymer is 50-80℃, and the reversible breakage efficiency of the DA bond is ≥90% in the range of 80-120℃.

[0010] Preferably, the mass fraction of hydrogen bond donors accounts for 10-30% of the self-healing material.

[0011] Preferably, the mass ratio of DA bond prepolymer to hydrogen bond donor is 6:4-8:2.

[0012] Preferably, the boron nitride nanosheets have a lateral dimension of 0.5-5 μm and a thickness of 10-100 nm, and the boron nitride nanosheets are uniformly dispersed in the dynamic reversible chemical bond network.

[0013] Preferably, the carbon quantum dots have a particle size of 2-10 nm, and when irradiated with an 808 nm wavelength laser, they generate a local temperature rise to 80-120°C, triggering the breakage of DA bonds to achieve non-destructive removal of the chip.

[0014] The method for preparing the self-healing material for electronic device packaging involves adding boron nitride nanosheets and carbon quantum dots to a DA bond prepolymer and dispersing them thoroughly; then adding a hydrogen bond donor and stirring thoroughly.

[0015] Preferably, furan-modified epoxy resin and bismaleimide are dissolved in N,N-dimethylformamide and stirred at 50-70°C for 5-7 hours to form DA prepolymer.

[0016] An electronic device packaging method involves spraying a self-healing material onto the surface of a substrate to form a 20-30 μm thick packaging layer; curing the layer at 80-120°C for 1-3 hours to form a three-dimensional interpenetrating network structure; wherein the self-healing material is either the self-healing material for electronic device packaging described above or the self-healing material for electronic device packaging obtained by the preparation method described above.

[0017] Even better, curing at 80°C for 2 hours forms an encapsulation layer with a thermal conductivity ≥2.5 W / m·K and a tensile strength ≥8 MPa.

[0018] Preferred packaging technology for Mini / Micro LED.

[0019] The self-healing material has a light transmittance of ≥90% (wavelength 450-650 nm) after curing, and an adhesion strength of ≥150 g to the Mini / MicroLED chip.

[0020] The mechanism of this invention is as follows: 1. Dynamic reversible chemical bond network: This invention adopts a synergistic system of Diels-Alder (DA) bonds and hydrogen bonds; DA bonds provide reversible breaking and recombination capabilities at high temperatures (80-120℃), while hydrogen bonds achieve rapid dynamic repair at room temperature. The synergy of the two ensures self-repair efficiency over a wide temperature range.

[0021] 2. Nano-reinforcing phase: The present invention adds surface-modified boron nitride (BN) nanosheets (mass fraction 5-15%), which significantly improves the thermal conductivity (≥2.5 W / m·K) and mechanical strength (tensile strength ≥8 MPa) of the material.

[0022] 3. Photothermal responsive agent: This invention introduces near-infrared absorbing carbon quantum dots (CQDs), which trigger the breakage of DA bonds by local heating through laser irradiation (wavelength 808 nm) during rework, thereby achieving non-destructive removal of the chip.

[0023] The beneficial effects of this invention compared to the prior art are as follows: 1. Highly efficient self-healing: Repairs micro-cracks within 30 minutes at room temperature (repair efficiency ≥95%), and restores the integrity of the encapsulation layer within 1 hour after the laser-triggered chip is removed; 2. High reliability: The material's coefficient of thermal expansion (CTE) matches that of the GaN chip (CTE=5.6 ppm / ℃), and there is no delamination after 500 thermal cycles (-40~125℃); 3. Green process: No solvent cleaning required, reducing waste by 90% during the rework process.

[0024] 4. Repairability: This material can automatically repair damaged areas after repair, supporting multiple repairs and improving the reliability and maintainability of Mini / Micro LED display panels.

[0025] 5. Reduced Costs: Self-healing materials can repair damage to the encapsulation layer, extending the lifespan of Mini / Micro LEDs. This reduces the scrap rate of Mini / Micro LEDs due to encapsulation layer damage, thus lowering production costs.

[0026] In summary, the encapsulation layer of this invention has rapid self-healing capability, supporting efficient rework; the material has high thermal conductivity, mechanical strength, and thermal expansion matching with LED chips; the self-healing process does not require high temperature or complex equipment, and is compatible with existing packaging production lines. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the self-healing material being sprayed onto the target substrate according to the present invention; Figure 2 This is a schematic diagram of the dynamic bond network of the self-healing material of the present invention; Figure 3 This is a side view of the target substrate after the mass transfer of Mini / Micro LED chips according to the present invention. Figure 4 This is a schematic diagram illustrating the removal of defective chips using the laser welding technology of this invention; Figure 5 This is a schematic diagram of the self-healing material after repair according to the present invention. Detailed Implementation

[0028] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto. Example 1

[0029] This embodiment proposes a method for preparing a self-healing material for electronic device packaging and a method for packaging electronic devices; 1. The raw materials and proportions of the self-healing material are as follows: DA bond prepolymer: epoxy furan resin (EP-FA, molecular weight 1200) and bismaleimide (BMI) are mixed in a 1:1 molar ratio; Hydrogen bond donor: NCO-terminated polyurethane prepolymer (PU, 20% by mass); the NCO-terminated polyurethane prepolymer is prepared by reacting excess diisocyanate with polyether / polyester polyol, with -NCO groups at the end.

[0030] Nano-reinforcing phase: Boron nitride nanosheets modified with silane coupling agent (BN, 10% by mass, lateral dimension 2 μm, thickness 30 nm). Photothermal responsive agent: near-infrared absorbing carbon quantum dots (CQDs, 0.5% by mass, 5 nm in particle size).

[0031] 2. The preparation steps of self-healing materials are as follows: 1) After mixing EP-FA and BMI, dissolve them in N,N-dimethylformamide (DMF) and stir at 60°C for 6 hours to form a DA bond prepolymer solution; 2) Add BN nanosheets and CQDs, and ultrasonically disperse for 30 minutes; 3) Then inject the NCO-terminated polyurethane prepolymer and mechanically stir for 2 hours to form a self-healing solution; the mass ratio of DA bond prepolymer to NCO-terminated polyurethane prepolymer is 6:4.

[0032] Curing / Reaction Mechanism: During the preparation process, the -NCO at the end of the prepolymer reacts with the remaining amino (-NH-) or hydroxyl (-OH) groups on the DA prepolymer (EP-FA) molecular chain to form urea bonds (-NH-CO-NH-) or urethane bonds (-NH-CO-O-), thereby covalently connecting the hydrogen bond network and the DA network together to form an interpenetrating network (IPN).

[0033] 3. Mini LED Packaging Steps 1) Perform plasma cleaning on the glass substrate (200 W power, 5 minutes) to remove organic contaminants; 2) Spray the self-healing material onto the surface of the glass substrate (see...). Figure 1 ), forming a 25 μm thick encapsulation layer; 3) Curing at 80℃ for 2 hours forms a three-dimensional interpenetrating network structure (see...). Figure 2 ); 4. Self-healing performance test Test 1: Microcrack Repair Simulated damage: A crack with a length of 1 mm and a depth of 10 μm was scratched on the surface of the encapsulation layer using a diamond probe; Repair conditions: Let stand at room temperature (25℃) for 30 minutes; Repair outcome: Scanning electron microscopy (SEM) shows that the crack is completely closed (see...). Figure 3 The tensile strength recovered to 8.2 MPa (initial value was 8.5 MPa), with a repair efficiency of 96.5%; the LED photoelectric performance (brightness, wavelength) was less than 2% different from that before the damage.

[0034] Test 2: Chip Rework and Encapsulation Layer Healing Repair procedure: 1) Irradiate the target chip with an 808 nm laser (power 2 W) for 5 seconds, and the local temperature of the encapsulation layer rises to 100℃, causing the DA bond to break; 2) The robotic arm removes the failed chip and cleans up any remaining packaging material (see...). Figure 4 ); Self-repair process: 1) Place on a 40℃ heating plate for 20 minutes to accelerate dynamic bond recombination; 2) Rebond the new chip (participate in) Figure 5 ); Repair results: The surface flatness (Ra) of the encapsulation layer was restored from 0.8 μm before repair to 0.5 μm; the bonding strength of the new chip is ≥150 g, and the brightness uniformity difference is <3%.

[0035] 5. Reliability Verification Test items: 1) Thermal cycling test (-40℃↔125℃, 200 cycles): No delamination or cracking of the encapsulation layer; chip brightness decay <5%.

[0036] 2) Double 85 test (85℃ / 85% RH, 96 hours): The light transmittance of the self-healing material remains ≥100% (initial value 92%); the adhesion strength between the encapsulation layer and the substrate decreases by <10%.

[0037] 3) Thermal conductivity: The thermal conductivity of the encapsulation layer is 2.8 W / m·K (measured by steady-state method); the junction temperature of the LED chip is 15℃ lower than that of traditional epoxy resin encapsulation. Example 2

[0038] This embodiment proposes a method for preparing a self-healing material for electronic device packaging and a method for packaging electronic devices; 1. The raw materials and proportions of the self-healing material are as follows: DA bond prepolymer: epoxy furan resin (EP-FA, molecular weight 1200) and bismaleimide (BMI) are mixed in a 1:1 molar ratio; Hydrogen bond donor: NCO-terminated polyurethane prepolymer (PU, 20% by mass); Nano-reinforcing phase: Boron nitride nanosheets modified with silane coupling agent (BN, 10% by mass, lateral dimension 2 μm, thickness 30 nm). Photothermal responsive agent: near-infrared absorbing carbon quantum dots (CQDs, 0.5% by mass, 5 nm in particle size).

[0039] 2. Preparation method of self-healing materials 1) Epoxy furan resin (EP-FA) and bismaleimide (BMI) are dissolved in DMF and stirred at 60°C for 6 hours to form DA prepolymer; 2) Add BN nanosheets (10 wt%) and CQDs (0.5 wt%), and ultrasonically disperse for 40 minutes; 3) Inject the NCO type polyurethane prepolymer into the injection end and mechanically stir for 2.5 hours.

[0040] 3. Packaging and Rework Testing 1) Spray a 20 μm thick self-healing layer onto the glass substrate (see...). Figure 1 After curing, the Mini LED chip is bonded. 2) After simulating mechanical damage, the LED photoelectric performance recovered to 98% of its initial value after being placed at room temperature for 30 minutes; 3) The failed chip was removed using an 808 nm laser (2 W power, 5 s irradiation time). After cleaning, the encapsulation layer self-repaired within 1 hour, and the brightness uniformity difference after bonding a new chip was <3%.

[0041] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all of these should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. A self-healing material for electronic device packaging, characterized in that, Includes the following components: A dynamic, reversible chemical bond network formed by the synergistic interaction of DA bond prepolymers and hydrogen bond donors; Boron nitride nanosheets with a mass fraction of 5-15%, wherein the boron nitride nanosheets are surface-modified with a silane coupling agent; Near-infrared absorbing carbon quantum dots with a mass fraction of 0.1-1%.

2. The self-healing material for electronic device packaging according to claim 1, characterized in that, The DA bond prepolymer is formed by reacting a furan-containing epoxy resin with a maleimide compound in a molar ratio of 1:0.8-1.2; the hydrogen bond donor is a polyurethane segment containing urea bonds or urethane groups.

3. The self-healing material for electronic device packaging according to claim 2, characterized in that, The mass fraction of hydrogen bond donors accounts for 10-30% of the self-healing material.

4. The self-healing material for electronic device packaging according to claim 3, characterized in that, The mass ratio of DA bond prepolymer to hydrogen bond donor is 6:4-8:

2.

5. The self-healing material for electronic device packaging according to claim 1, characterized in that, The boron nitride nanosheets have a lateral dimension of 0.5-5 μm and a thickness of 10-100 nm, and are uniformly dispersed in the dynamic reversible chemical bond network.

6. The self-healing material for electronic device packaging according to claim 1, characterized in that, The carbon quantum dots have a particle size of 2-10 nm. When irradiated with an 808 nm wavelength laser, they generate a local temperature rise to 80-120°C, triggering the breakage of the DA bond to achieve non-destructive removal of the chip.

7. The method for preparing a self-healing material for electronic device packaging as described in any one of claims 1-6, characterized in that, Boron nitride nanosheets and carbon quantum dots were added to the DA bond prepolymer and dispersed thoroughly; then hydrogen bond donors were added and stirred thoroughly.

8. The method for preparing a self-healing material for electronic device packaging according to claim 7, characterized in that, Furan-modified epoxy resin and bismaleimide are dissolved in N,N-dimethylformamide and stirred at 50-70°C for 5-7 hours to form DA prepolymer.

9. A method for packaging electronic devices, characterized in that, The self-healing material is sprayed onto the substrate surface to form a 20-30 μm thick encapsulation layer; it is then cured at 80-120℃ to form a three-dimensional interpenetrating network structure; the self-healing material is the self-healing material according to any one of claims 1-6 or the self-healing material obtained by the preparation method according to claim 8.

10. The electronic device packaging method according to claim 9, characterized in that, Packaging technology applied to Mini / MicroLED.

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