Micro-LED (Light Emitting Diode) laser mass transfer and release material as well as preparation method and application thereof

Abstract

The invention provides a Micro-LED (Light Emitting Diode) laser mass transfer and release material as well as a preparation method and application thereof. The Micro-LED laser mass transfer and release material is prepared from the following components in percentage by mass: 12 to 50 percent of azobenzene modified epoxy resin, 1 to 10 percent of auxiliary material resin, 0.01 to 1 percent of coupling agent, 0.1 to 1.8 percent of flatting agent and 0.01 to 1.5 percent of antioxidant. The specific composition of the Micro-LED laser mass transfer and release material is designed, azobenzene modified epoxy resin is used as matrix resin, the Micro-LED laser mass transfer and release material with excellent performance is prepared, and the Micro-LED laser mass transfer and release material has good high temperature resistance, acid and alkali resistance and high adhesive force, and can be applied to the field of light emitting devices. The bonding agent can be firmly bonded with a chip under the conditions of high temperature and acid and alkali, defect-free bonding is realized, and laser release of the chip can be realized, so that the transfer efficiency of the chip is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of Micro-LED laser mass transfer materials, and particularly relates to a Micro-LED laser mass transfer release material, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of display technology, Micro LED technology is regarded as a strong candidate for future display technology due to its excellent display performance, including high brightness, low power consumption, long lifespan, and fast response time. The high-density integration of Micro LEDs is the key to realizing their application in the display field, and the mass transfer technology is a decisive step in the manufacturing process. The efficiency and precision of this step are directly related to the performance and cost-effectiveness of the final product.

[0003] However, the existing Micro LED mass transfer technologies face multiple challenges. During the process of transferring Micro LED chips to the laser-induced release layer and etching, the high temperature generated may cause the chips to shift in position, which not only reduces the transfer precision but also affects the overall production efficiency. In addition, the existing materials have insufficient high-temperature resistance during the etching process, limiting their stability and application range in high-temperature environments. During the Micro LED mass transfer process, chemical solvents such as acids and alkalis are also required for cleaning and treatment, which puts higher requirements on the acid and alkali resistance of the materials and their adhesion in acid and alkali environments. And strong adhesion often affects their cleaning performance. The current Micro LED manufacturing materials do not perform well in terms of acid and alkali resistance and adhesion, which directly affects the reliability and durability of the products.

[0004] In view of this, it is particularly urgent to develop a new type of Micro LED laser mass transfer release material. This material needs to have the properties of high temperature resistance, acid and alkali resistance, and strong adhesion, and be able to firmly bond with the chips under high temperature and acid and alkali conditions to achieve defect-free bonding. At the same time, the material should also be able to achieve laser release at low energy thresholds at multiple wavelengths to improve the transfer efficiency, and be able to achieve residue-free cleaning after the process is completed, improve the chip lighting success rate, and reduce production costs. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a Micro-LED laser mass transfer release material, its preparation method and application. By designing the specific composition of the Micro-LED laser mass transfer release material, using azobenzene-modified epoxy resin as the main resin, a Micro-LED laser mass transfer release material with excellent performance is prepared. This Micro-LED laser mass transfer release material has good high-temperature resistance, acid and alkali resistance, and high adhesion. It can be firmly bonded to the chip under high-temperature and acid-base conditions to achieve defect-free bonding. At the same time, the Micro-LED laser mass transfer release material provided by the present invention can achieve laser release of the chip at multiple wavelengths and low energy thresholds to improve the transfer efficiency of the chip. Moreover, after the Micro-LED laser mass transfer process is completed, it can achieve residue-free cleaning, improve the chip lighting success rate, and reduce production costs.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a Micro-LED laser mass transfer release material, and the Micro-LED laser mass transfer release material comprises components with the following mass percentages:

[0008]

[0009] By designing the specific composition of the Micro-LED laser mass transfer release material, using azobenzene-modified epoxy resin as the main resin, a Micro-LED laser mass transfer release material with excellent performance is prepared. This Micro-LED laser mass transfer release material has good high-temperature resistance, acid and alkali resistance, and high adhesion. It can be firmly bonded to the chip under high-temperature and acid-base conditions to achieve defect-free bonding. At the same time, the Micro-LED laser mass transfer release material provided by the present invention can achieve laser release of the chip at multiple wavelengths and low energy thresholds to improve the transfer efficiency of the chip. Moreover, after the Micro-LED laser mass transfer process is completed, it can achieve residue-free cleaning, improve the chip lighting success rate, and reduce production costs.

[0010] In the present invention, the azobenzene-modified epoxy resin is the main resin of the Micro-LED laser mass transfer and release material system, which is the main component used to form the mass transfer and release material. It has a high glass transition temperature, is resistant to strong acids and strong alkalis, and has strong absorption of ultraviolet lasers. It plays a role in better laser-induced release of micro light-emitting diode chips; the auxiliary resin plays a role in improving the stability of the material system and the rheological properties of the material; the coupling agent plays a role in enhancing the adhesion of the material to the substrate; the leveling agent can reduce the surface tension of the coating, ensure that the glue is spin-coated on the substrate smoothly and with good smoothness, and improve TTV.

[0011] In the present invention, by controlling the amount of the main resin azobenzene-modified epoxy resin in the Micro-LED laser mass transfer and release material within a specific range, a Micro-LED laser mass transfer and release material with excellent performance is prepared. If the amount of azobenzene-modified epoxy resin in the Micro-LED laser mass transfer and release material is too small, the prepared Micro-LED laser mass transfer and release material has a weak laser effect and cannot transfer the chips well; if the amount of azobenzene-modified epoxy resin in the Micro-LED laser mass transfer and release material is too large, the force generated by the prepared Micro-LED laser mass transfer and release material after laser irradiation is too large, resulting in deviation during chip transfer or damage to the chips.

[0012] In the present invention, the mass percentage content of azobenzene-modified epoxy resin in the Micro-LED laser mass transfer and release material can be 12%, 15%, 18%, 21%, 24%, 27%, 30%, 35%, 40%, 45% or 50%, etc.

[0013] The mass percentage content of the auxiliary resin in the Micro-LED laser mass transfer and release material can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.

[0014] The mass percentage content of the coupling agent in the Micro-LED laser mass transfer and release material can be 0.01%, 0.15%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0015] The mass percentage content of the leveling agent in the Micro-LED laser mass transfer and release material can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6% or 1.8%, etc.

[0016] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0017] As a preferred technical solution of the present invention, the raw materials for preparing the azobenzene-modified epoxy resin include an epoxy resin monomer and aminoazobenzene.

[0018] Preferably, the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is (0.3 - 5):1, and for example, it can be 0.3:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, etc.

[0019] In the present invention, by controlling the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene within a specific range, a Micro-LED laser mass transfer release material with excellent performance is prepared. If the molar ratio of the epoxy group to the amino group is too small, that is, the amount of the epoxy group is too small, or the molar ratio of the epoxy group to the amino group is too large, that is, the amount of the epoxy group is too large, it will result in too low number-average molecular weight of the synthesized azobenzene-modified epoxy resin, and further cause poor heat resistance and low glass transition temperature of the azobenzene-modified epoxy resin, and it cannot form a film after coating and drying.

[0020] It should be noted that in the present invention, the test method for the epoxy group content in the epoxy resin can be obtained by referring to the national standard GB / T 4612 - 2008.

[0021] Preferably, the epoxy resin includes any one or a combination of at least two of bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, hydrogenated bisphenol A epoxy resin, tetrabromobisphenol A epoxy resin, resorcinol epoxy resin, resorcinol formaldehyde epoxy resin, o-cresol epoxy resin, p-cresol epoxy resin, p-tert-butylphenol epoxy resin, hydroquinone epoxy resin, trimethylolphenol epoxy resin, bis(4-aminophenoxy)phenyl epoxy resin, bis(3-aminophenoxy)phenyl epoxy resin, bis(2-aminoethyl)phenyl epoxy resin, bis(3-glycidyloxy phenoxy)phenyl epoxy resin, bis(4-glycidyloxy phenoxy)phenyl epoxy resin, bis(2-glycidyloxy ethoxy)phenyl epoxy resin, bis(3-glycidyloxy propoxy)phenyl epoxy resin or bis(4-glycidyloxy butoxy)phenyl epoxy resin.

[0022] Preferably, the aminoazobenzene is selected from any one or a combination of at least two of 4,4'-diaminoazobenzene, 4-amino-4'-dimethylaminoazobenzene, 4-amino-4'-methylaminoazobenzene, 2,3-difluoro-4-aminoazobenzene, ethyl 4-((4-aminophenyl)azo)benzoate, 4-aminoazobenzene, 4-amino-4',4'-diethylaminoazobenzene, or 4-amino-4'-hydroxyaminoazobenzene.

[0023] As a preferred technical solution of the present invention, the azobenzene-modified epoxy resin is prepared by the following method, and the method includes the following steps:

[0024] React an epoxy resin monomer with aminoazobenzene to obtain the azobenzene-modified epoxy resin;

[0025] Preferably, the temperature of the reaction is 120 - 180 °C (for example, it can be 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, or 180 °C, etc.), and the time is 6 - 48 h (for example, it can be 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, or 48 h, etc.).

[0026] As a preferred technical solution of the present invention, based on the mass percentage content of the Micro-LED laser mass transfer release material being 100%, the mass percentage content of the azobenzene-modified epoxy resin is 18 - 35%, for example, it can be 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, or 35%, etc.

[0027] As a preferred technical solution of the present invention, the auxiliary resin includes any one or a combination of at least two of 1,3-phenylene phosphoric acid tetra(2,6-dimethylphenyl) ester (condensate), polystyrene, polyvinyl chloride, poly-1-butene, polyacrylonitrile, polybutyl maleate, poly(maleic anhydride-2-2-ethyl ethyl ester), polyvinyl acetate, ABS (acrylonitrile-butadiene-styrene copolymer), SBS (styrene-butadiene-styrene block copolymer), MBS (methyl methacrylate-butadiene-styrene copolymer), styrene acrylic resin, acrylic acid-acrylic ether copolymer, acrylate-acrylic acid butanediol ester, styrene-N-phenyl maleimide-maleic anhydride graft copolymer, polycarbonate, polyimide, polyether ether ketone, or ternary acrylate copolymer.

[0028] Preferably, the styrene acrylic resin includes an acrylate-styrene copolymer.

[0029] Preferably, the ternary acrylate copolymer includes an acrylate-acrylate-styrene copolymer.

[0030] Preferably, based on the mass percentage content of the Micro-LED laser mass transfer release material being 100%, the mass percentage content of the auxiliary resin is 2-5%, for example, it can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc.

[0031] As a preferred technical solution of the present invention, based on the mass percentage content of the Micro-LED laser mass transfer release material being 100%, the mass percentage content of the coupling agent is 0.05-0.3%, for example, it can be 0.05%, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%, etc.

[0032] Preferably, the coupling agent includes any one or at least two combinations of LA-120 (vinyltrichlorosilane), LA-151 (vinyltriethoxysilane), LA-171 (vinyltrimethoxysilane), LA-2331 (vinyltriisopropoxysilane), LA-297 (vinyltriisopropenyloxysilane), LA-2150 (methylvinyldichlorosilane), LA-2151 (methylvinyldiethoxysilane), LA-2171 (methylvinyldimethoxysilane), LA-550 (3-aminopropyltriethoxysilane), LA-551 (3-aminopropyltrimethoxysilane), KH550 (γ-aminopropyltriethoxysilane), KH560 (γ-glycidoxypropyltrimethoxysilane), KH570 (γ-methacryloxypropyltrimethoxysilane), KH590 (γ-mercaptopropyltrimethoxysilane), KH792 (N-β(aminoethyl)-γ-aminopropyltrimethoxysilane), KH793 (N-(2-aminoethyl)-3-aminopropyltriethoxysilane), KH602 (N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane) or KH603 (N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane).

[0033] Preferably, based on the mass percentage content of the Micro-LED laser mass transfer release material being 100%, the mass percentage content of the leveling agent is 0.3-1%, for example, it can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0034] Preferably, the leveling agent includes any one or at least two combinations of an acrylic leveling agent, a fluorocarbon leveling agent or a silicone leveling agent.

[0035] Preferably, the acrylic leveling agent includes a polyester-modified polydimethylsiloxane solution with acrylate functional groups (using xylene as the solvent).

[0036] Preferably, the fluorocarbon leveling agent includes a fluorocarbon-modified polyacrylic wax.

[0037] Preferably, the silicone leveling agent comprises polyether-modified siloxane and / or polyether-modified polydimethylsiloxane.

[0038] As a preferred technical solution of the present invention, the Micro-LED laser mass transfer release material further comprises an antioxidant.

[0039] Preferably, based on the mass percentage content of the Micro-LED laser mass transfer release material being 100%, the mass percentage content of the antioxidant is 0.01-1.5% (for example, it can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.1%, 1.2%, 1.3%, 1.4% or 1.5%, etc.), preferably 0.1-0.5%.

[0040] Preferably, the antioxidant comprises any one or a combination of at least two of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 405, antioxidant DLTDP, antioxidant 1790, antioxidant 164, antioxidant DNP, antioxidant DLTP, antioxidant TNP, antioxidant TPP, and antioxidant MB.

[0041] Preferably, the Micro-LED laser mass transfer release material further comprises a solvent.

[0042] Preferably, based on the mass percentage content of the Micro-LED laser mass transfer release material being 100%, the mass percentage content of the solvent is 50-85%, for example, it can be 50%, 52%, 55%, 60%, 65%, 70%, 75%, 80%, 83% or 85%, etc.

[0043] Preferably, the solvent comprises any one or a combination of at least two of ketone solvents, aromatic hydrocarbon solvents, ether solvents, amide solvents, dimethyl sulfoxide, decahydronaphthalene or ester solvents.

[0044] Preferably, the ketone solvents comprise any one or a combination of at least two of acetone, butanone, cyclohexanone, and isophorone.

[0045] Preferably, the aromatic hydrocarbon solvents comprise toluene and / or mesitylene.

[0046] Preferably, the ether solvents comprise any one or a combination of at least two of dioxane, 1,3-dioxolane, 2,2,4,4,5,5-hexamethyl-1,3-dioxolane, 2,2-dimethoxy-4-(trifluoromethyl)-1,3-dioxolane ether, tetrahydrofuran or fluorinated hexacyclic coordination ether.

[0047] Preferably, the amide solvent includes dimethylformamide and / or N,N-dimethylacetamide.

[0048] Preferably, the ester solvent includes any one or a combination of at least two of ethyl acetate, ethyl acetate, butyl acetate, isopropyl acetate, propyl acetate, isoamyl acetate, benzyl acetate, butyl butyrate, trimethyl phosphate, triethyl phosphate, ethyl acrylate, methyl methacrylate, dioctyl adipate or propylene glycol monomethyl ether acetate.

[0049] Preferably, the number of types of the solvent does not exceed 4 (for example, it can be 1, 2, 3 or 4).

[0050] In a second aspect, the present invention provides a preparation method of the Micro-LED laser mass transfer release material as described in the first aspect, and the preparation method includes the following steps:

[0051] Mix all components of the Micro-LED laser mass transfer release material to obtain the Micro-LED laser mass transfer release material.

[0052] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0053] (1) Mix the azobenzene-modified epoxy resin and the auxiliary resin to obtain mixture 1;

[0054] (2) Mix mixture 1 and part of the solvent to obtain mixture 2;

[0055] (3) Mix mixture 2 with a coupling agent, an antioxidant, a leveling agent and the remaining solvent to obtain the Micro-LED laser mass transfer release material.

[0056] As a preferred technical solution of the present invention, the mixing method in step (1) includes stirring, and the rotation speed of the stirring is 40 - 60 rpm, for example, it can be 40 rpm, 42 rpm, 44 rpm, 46 rpm, 48 rpm, 50 rpm, 52 rpm, 54 rpm, 56 rpm, 58 rpm or 60 rpm, etc.

[0057] Preferably, the mixing method in step (2) includes stirring, the rotation speed of the stirring is 80 - 180 rpm (for example, it can be 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 160 rpm, 170 rpm or 180 rpm, etc.), and the time is 6 - 10 h (for example, it can be 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h or 10.5 h, etc.).

[0058] Preferably, the mixing method in step (3) includes stirring, and the rotation speed of the stirring is 180 - 320 rpm (for example, it can be 180 rpm, 190 rpm, 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, 300 rpm, 310 rpm or 320 rpm, etc.), and the time is 45 - 55 h (for example, it can be 45 h, 46 h, 47 h, 48 h, 49 h, 50 h, 51 h, 52 h, 53 h, 54 h or 55 h, etc.).

[0059] Preferably, after the mixing in step (3), it further includes a post - treatment step, and the post - treatment method includes standing and filtering.

[0060] Preferably, the filtering method includes filtering successively with filter elements having pore sizes of 1 μm, 0.45 μm, and 0.2 μm.

[0061] It should be noted that the solvent added in step (2) accounts for 75 - 85% of the total mass of the solvent, for example, it can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85%, etc.

[0062] In a third aspect, the present invention provides an application of the Micro - LED laser mass transfer release material as described in the first aspect, and the Micro - LED laser mass transfer release material is used for the laser mass transfer of Micro - LED.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] (1) By designing the specific composition of the Micro-LED laser mass transfer release material, using azobenzene-modified epoxy resin as the main resin and controlling its dosage within a specific range, a Micro-LED laser mass transfer release material with excellent performance is prepared. This Micro-LED laser mass transfer release material has good high-temperature resistance, acid and alkali resistance, and high adhesion. It can be firmly bonded to the chip under high-temperature and acid-base conditions to achieve defect-free bonding. At the same time, the Micro-LED laser mass transfer release material provided by the present invention can achieve laser release of the chip at multiple wavelengths and low energy thresholds to improve the transfer efficiency of the chip. Moreover, after the Micro-LED laser mass transfer process is completed, it can achieve residue-free cleaning, improve the chip lighting success rate, and reduce production costs. Its glass transition temperature is 52-130 °C, the crosshatch grade after acid soaking is 4B or 5B, and the crosshatch grade after alkali soaking is 4B or 5B. When the Micro-LED laser mass transfer release material provided by the present invention is used for Micro-LED laser mass transfer, the cleaning performance is that there is no residue glue on the chip, and the chip transfer yield ≥ 99.12%, specifically 99.12-99.99%.

[0065] (2) In the present invention, through the combined action of each component, the dosage range of each component is optimized, and the mass ratio of the epoxy resin monomer and aminoazobenzene, the raw materials for preparing the azobenzene-modified epoxy resin, is controlled within a specific range, further optimizing the comprehensive performance of the Micro-LED laser mass transfer release material. Its glass transition temperature is 102-115 °C, the crosshatch grade after acid soaking is 5B, and the crosshatch grade after alkali soaking is 5B. When the Micro-LED laser mass transfer release material provided by the present invention is used for Micro-LED laser mass transfer, the cleaning performance is that there is no residue glue on the chip, and the chip transfer yield ≥ 99.79%, specifically 99.79-99.99%. Brief Description of the Drawings

[0066] Figure 1 It is a schematic diagram of the chip accuracy after the chip mass transfer using the Micro-LED laser mass transfer release material provided by Example 1 of the present invention. Detailed Embodiments

[0067] The technical solutions of the present invention will be further described below in conjunction with the drawings and through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0068] The sources of some components in the following embodiments and comparative examples are shown in Table 1 below:

[0069] Table 1

[0070]

[0071] Preparation Examples 1-3, Comparative Preparation Examples 1-2

[0072] This preparation example provides an azobenzene-modified epoxy resin and its synthesis method. The synthesis method of the azobenzene-modified epoxy resin is as follows:

[0073] At 150 °C, the epoxy resin and aminoazobenzene react for 20 h to obtain the azobenzene-modified epoxy resin;

[0074] Among them, in Preparation Example 1, the epoxy resin is bisphenol A epoxy resin, the aminoazobenzene is 4,4'-diaminoazobenzene, and the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is 0.35:1;

[0075] In Preparation Example 2, the epoxy resin is bisphenol F epoxy resin, the aminoazobenzene is 4-amino-4'-dimethylaminoazobenzene, and the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is 3:1;

[0076] In Preparation Example 3, the epoxy resin is resorcinol formaldehyde epoxy resin, the aminoazobenzene is 4-amino-4'-methylaminoazobenzene, and the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is 5:1;

[0077] In Comparative Preparation Example 1, the epoxy resin is bisphenol A epoxy resin, the aminoazobenzene is 4,4'-diaminoazobenzene, and the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is 0.2:1;

[0078] In Comparative Preparation Example 2, the epoxy resin is bisphenol A epoxy resin, the aminoazobenzene is 4,4'-diaminoazobenzene, and the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is 7:1;

[0079] Among them, the test method for the epoxy group content in the epoxy resin is obtained by referring to the national standard GB / T 4612-2008 for testing.

[0080] Examples 1-15, Comparative Examples 1-4

[0081] Examples 1-15, Comparative Examples 1-4 respectively provide a Micro-LED laser mass transfer release material. The composition of the Micro-LED laser mass transfer release material is shown in Tables 2-4 below. The dosages of each component in Tables 2-4 are in mass percentages.

[0082] The preparation method of the above Micro-LED laser mass transfer release material is as follows:

[0083] (1) Stir and mix the azobenzene-modified epoxy resin and the auxiliary resin evenly under the condition of a rotation speed of 50 rpm;

[0084] (2) Add part of the solvent (the added solvent accounts for 80 wt% of the total solvent usage), adjust the rotation speed to 100 rpm and stir for 4 h, then adjust the rotation speed to 150 rpm and stir for 4 h to mix evenly;

[0085] (3) Then add the coupling agent, leveling agent, antioxidant and the remaining solvent, stir and mix at 200 rpm for 24 h, then adjust the rotation speed to 300 rpm and stir for 24 h, then let it stand for 24 h, and filter successively with filter elements with pore sizes of 1 μm, 0.45 μm, and 0.2 μm to obtain the Micro-LED laser mass transfer release material.

[0086] Test the performance of the Micro-LED laser mass transfer release materials provided in the above examples and comparative examples. The specific test methods are as follows:

[0087] (I) Glass transition temperature:

[0088] Spin-coat the Micro-LED laser mass transfer release materials provided in the above examples and comparative examples on the crystallized glass slides, dry and scrape the film, and perform DSC testing on the obtained film materials. The spin-coating conditions are 2000 rpm @ 30 s, and the drying conditions are 120 °C @ 10 min;

[0089] Test the glass transition temperature according to the national standard GB / T 15022.2~5. Set the experimental conditions on the differential scanning calorimeter, including a heating rate of 5 °C / min, a nitrogen atmosphere, and a temperature range of -20 to 250 °C.

[0090] (II) Cross-cut adhesion grade after acid dipping:

[0091] Before the cross-cut test, spin-coat and dry the Micro-LED laser mass transfer release materials provided in the above examples and comparative examples on the sapphire substrate. The spin-coating conditions can be 2000 rpm @ 30 s, and the drying conditions can be 120 °C @ 10 min, and then perform the cross-cut test. The cross-cut test is a test method for evaluating the surface adhesion of materials (national standard for cross-cut test: GB / T 9286-2021). The specific steps are as follows:

[0092] (1) Score and acid dip: Use a cross-cut knife to draw 10×10 small grids of 1 mm×1 mm on the surface of the test sample. After each score reaches the bottom layer of the paint, immerse it in an 8% mass concentration HCl solution for 30 min;

[0093] (2) Clean: Brush the debris in the test area clean with a brush;

[0094] (3) Tape test: Use 3M No. 600 adhesive tape or equivalent tape to firmly stick to the small grid to be tested, and use an eraser to wipe the tape forcefully to increase the contact area and force between the tape and the tested area;

[0095] (4) Peeling: After standing for 4 minutes, hold one end of the tape by hand and quickly tear off the tape in the vertical direction (90°). Conduct 2 identical tests at the same position;

[0096] (5) Result evaluation: According to the peeling situation of the coating, evaluate the adhesion grade according to the standard. Usually, the test results will be represented by numbers and letters to indicate the quality grade of the adhesion;

[0097] Among them, the result grade evaluation criteria for the cross-cut test are as follows:

[0098] ISO grade 0 / ASTM grade 5B: The edges of the cuts are completely smooth, and there is no peeling at the grid edges;

[0099] ISO grade 1 / ASTM grade 4B: There are small flakes of peeling at the intersections of the cuts, and the actual damage in the cross-cut area does not exceed 5%;

[0100] ISO grade 2 / ASTM grade 3B: The edges and / or intersections of the cuts are peeled off, and the area is greater than 5%, but less than 15%;

[0101] ISO grade 3 / ASTM grade 2B: There is partial peeling or large-scale peeling along the cut edges, or some grids are peeled off entirely. The peeled area exceeds 15%, but is less than 35%;

[0102] ISO grade 4 / ASTM grade 1B: Large-scale peeling occurs at the cut edges, or some squares are partially or completely peeled off, and the area is greater than 35% of the specified area, but does not exceed 65%;

[0103] ISO grade 5 / ASTM grade 0B: Exceeds the previous grade.

[0104] (III) Cross-cut grade after caustic soda treatment:

[0105] The difference from the cross-cut grade after pickling is as follows: (1) Scratching and caustic soda treatment: Use a cross-cut knife to draw 10×10 small grids of 1mm×1mm on the surface of the test sample. Each scratch should reach the bottom layer of the paint, and then immerse it in a potassium hydroxide solution with a mass concentration of 40% for 10 minutes;

[0106] Other steps and evaluation criteria are the same as above.

[0107] (IV) Cleaning performance: After completing the chip transfer process (for the chip transfer method, refer to the chip mass transfer method provided in CN118366916A), soak the receiving layer with chips at room temperature in the solvent corresponding to the glue solution for 10 minutes. Take out the receiving layer material, rinse it with IPA (isopropyl alcohol), dry it at 100 °C for 10 minutes, and observe under a microscope for any residual glue on the chips.

[0108] (V) Chip transfer yield:

[0109] The ratio of the chips that can be lit after transfer to the total transferred chips. For the chip transfer method, refer to the chip mass transfer method provided in CN118366916A. The Micro-LED laser mass transfer release materials provided in the above examples and comparative examples are used to prepare the laser-induced release layer.

[0110] Among them, the schematic diagram of the chip accuracy after chip mass transfer using the Micro-LED laser mass transfer release material provided in Example 1 of the present invention is as Figure 1 shown. It can be seen from Figure 1 that the Micro-LED laser mass transfer release material provided by the present invention can achieve high-precision and high-yield transfer, and the transfer yield exceeds 99.99%.

[0111] Table 2

[0112]

[0113]

[0114] Table 3

[0115]

[0116] Table 4

[0117]

[0118]

[0119] As can be seen from the above, by designing the specific composition of the Micro-LED laser mass transfer release material, using azobenzene-modified epoxy resin as the main resin and controlling its dosage within a specific range, a Micro-LED laser mass transfer release material with excellent performance is prepared. The Micro-LED laser mass transfer release material has good high-temperature resistance, acid and alkali resistance, and high adhesion, and can be firmly bonded to the chip under high-temperature, acid, and alkali conditions to achieve defect-free bonding. At the same time, the Micro-LED laser mass transfer release material provided by the present invention can achieve laser release of the chip at multiple wavelengths and low energy thresholds to improve the transfer efficiency of the chip. Moreover, after the Micro-LED laser mass transfer process is completed, it can achieve residue-free glue cleaning, improve the chip lighting success rate, and reduce production costs. Its glass transition temperature is 52-130°C, the cross-cut grade after acid dipping is 4B or 5B, and the cross-cut grade after alkali dipping is 4B or 5B. When the Micro-LED laser mass transfer release material provided by the present invention is used for Micro-LED laser mass transfer, the cleaning performance is that there is no residual glue on the chip, and the chip transfer yield is ≥99.12%, specifically 99.12-99.99%.

[0120] Furthermore, through the cooperative action of each component, optimizing the dosage range of each component, and controlling the mass ratio of the epoxy resin monomer and aminoazobenzene, the raw materials for preparing the azobenzene-modified epoxy resin, within a specific range, the comprehensive performance of the Micro-LED laser mass transfer release material is further optimized. Its glass transition temperature is 102-115°C, the cross-cut grade after acid dipping is 5B, and the cross-cut grade after alkali dipping is 5B. When the Micro-LED laser mass transfer release material provided by the present invention is used for Micro-LED laser mass transfer, the cleaning performance is that there is no residual glue on the chip, and the chip transfer yield is ≥99.79%, specifically 99.79-99.99%.

[0121] In summary, by designing the specific composition of the Micro-LED laser mass transfer release material and using azobenzene-modified epoxy resin as the main resin, a Micro-LED laser mass transfer release material with excellent performance is prepared.

[0122] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A Micro-LED laser mass transfer release material, characterized in that: The Micro-LED laser mass transfer release material includes the following components in percentage by mass: Azobenzene modified epoxy resin 12-50%; Auxiliary resin 1-10%; Coupling agent 0.01-1%; Leveling agent 0.1-1.8%; Antioxidant 0.01-1.5%.

2. The Micro-LED laser mass transfer release material according to claim 1, characterized in that: The raw materials for preparing the azobenzene-modified epoxy resin include epoxy resin and aminoazobenzene; Preferably, the molar ratio of the epoxy group in the epoxy resin to the amino group in the aminoazobenzene is (0.3-5):1; Preferably, the epoxy resin comprises any one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, tetrabromobisphenol A epoxy resin, resorcinol epoxy resin, resorcinol formaldehyde epoxy resin, o-cresol epoxy resin, p-cresol epoxy resin, p-tert-butylphenol epoxy resin, hydroquinone epoxy resin, trimethylolphenol epoxy resin, bis(4-aminophenoxy)phenyl epoxy resin, bis(3-aminophenoxy)phenyl epoxy resin, bis(2-aminoethyl)phenyl epoxy resin, bis(3-glycidyloxyphenoxy)phenyl epoxy resin, bis(4-glycidyloxyphenoxy)phenyl epoxy resin, bis(2-glycidyloxyethoxy)phenyl epoxy resin, bis(3-glycidyloxypropoxy)phenyl epoxy resin or bis(4-glycidyloxybutoxy)phenyl epoxy resin, or a combination of at least two thereof; Preferably, the aminoazobenzene is selected from any one or a combination of at least two of 4,4'-diaminoazobenzene, 4-amino-4'-dimethylaminoazobenzene, 4-amino-4'-methylaminoazobenzene, 2,3-difluoro-4-aminoazobenzene, ethyl 4-((4-aminophenyl)azo)benzoate, 4-aminoazobenzene, 4-amino-4',4'-diethylaminoazobenzene or 4-amino-4'-hydroxyaminoazobenzene.

3. The Micro-LED laser mass transfer release material according to claim 2, characterized in that: The azobenzene-modified epoxy resin is prepared by the following method, which comprises the following steps: reacting epoxy resin monomer and aminoazobenzene to obtain the azobenzene-modified epoxy resin; Preferably, the reaction temperature is 120-180°C and the reaction time is 6-48h.

4. The Micro-LED laser mass transfer release material according to any one of claims 1 to 3, characterized in that: Taking the mass percentage of the Micro-LED laser mass transfer release material as 100%, the mass percentage of the azobenzene-modified epoxy resin is 18-35%.

5. The Micro-LED laser mass transfer release material according to any one of claims 1 to 4, characterized in that: The auxiliary resin includes any one of 1,3-phenylene tetrakis (2,6-dimethylphenyl) phosphate (condensation polymer), polystyrene, polyvinyl chloride, poly-1-butene, polyacrylonitrile, polybutylene maleate, polymaleic anhydride-2-2 ethyl ethyl, polyvinyl acetate, ABS, SBS, MBS, styrene acrylic resin, acrylic acid-acrylic ether copolymer, acrylate-butylene glycol acrylate, styrene-N-phenyl maleimide-maleic anhydride graft copolymer, polycarbonate, polyimide, polyetheretherketone or ternary acrylate copolymer. A combination of at least two of the following; Preferably, taking the mass percentage of the Micro-LED laser mass transfer release material as 100%, the mass percentage of the auxiliary resin is 2-5%.

6. The Micro-LED laser mass transfer release material according to any one of claims 1 to 5, characterized in that: Taking the mass percentage of the Micro-LED laser mass transfer release material as 100%, the mass percentage of the coupling agent is 0.05-0.3%; Preferably, based on the mass percentage of the Micro-LED laser mass transfer release material being 100%, the mass percentage of the leveling agent is 0.3-1%.

7. The Micro-LED laser mass transfer release material according to any one of claims 1 to 6, characterized in that: The Micro-LED laser mass transfer release material also includes an antioxidant; Preferably, based on the mass percentage of the Micro-LED laser mass transfer release material as 100%, the mass percentage of the antioxidant is 0.01-1.5%, preferably 0.1-0.5%; Preferably, the Micro-LED laser mass transfer release material further comprises a solvent; Preferably, based on the mass percentage of the Micro-LED laser mass transfer release material being 100%, the mass percentage of the solvent is 50-85%.

8. A method for preparing a Micro-LED laser mass transfer release material according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: All components of the Micro-LED laser mass transfer release material are mixed to obtain the Micro-LED laser mass transfer release material.

9. The preparation method according to claim 8, characterized in that: The preparation method comprises the following steps: (1) mixing an azobenzene-modified epoxy resin and an auxiliary resin to obtain a mixture 1; (2) mixing mixture 1 and part of the solvent to obtain mixture 2; (3) Mixing mixture 2 with a coupling agent, an antioxidant, a leveling agent and the remaining solvent to obtain the Micro-LED laser mass transfer release material.

10. An application of the Micro-LED laser mass transfer release material according to any one of claims 1 to 7, characterized in that: The Micro-LED laser mass transfer release material is used for laser mass transfer of Micro-LED.

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