A photosensitive composite material for laser-assisted micro-led mass transfer and a preparation method and application thereof

Abstract

The application provides a photosensitive composite material for laser-assisted MicroLED mass transfer, comprising: a random copolymer represented by formula (I) and a photosensitive small molecule. A new transfer composite material is prepared by mixing the polymer and azo sulfone small molecule in a certain proportion. The polymer part can realize mechanical property and thermal property adjustment by simply adjusting the type of comonomer, so that it has high adhesion, can be spin-coated into a smooth film, and provides the overall network skeleton of the film layer. The azo sulfone small molecule serves as a photosensitive component, and the performance is adjusted by adjusting the type of side chain group on the aniline raw material, so that it has high selective absorption to different wavelengths of laser, decomposes to generate a large amount of gas to generate a driving force to transfer the core particle. Through optimization of the synthesis steps, the yield of the polymer and the small molecule is improved, and no subsequent complex purification steps are required. The core particle pickup step can achieve a yield of more than 99%, and the core particle release step can completely release a small part of the area.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a photosensitive composite material for laser-assisted MicroLED mass transfer, its preparation method, and its application. Background Technology

[0002] Micro LED is a highly promising next-generation display technology. Mass transfer, a key factor restricting its mass production, is a process of transferring millions to hundreds of millions of LED chips from an epitaxial substrate to a light-emitting substrate. Industrial production places high demands on transfer yield, transfer accuracy, and transfer rate. Currently, the mainstream mass transfer technologies include fluid self-loading transfer, roller transfer, PDMS stamp transfer, and laser-assisted mass transfer. Among these, laser-assisted mass transfer is more suitable for large-screen display production. Laser-assisted transfer can be further divided into laser-induced interface ablation and decomposition, laser-induced interface bubbling, and laser-induced interface stress assistance. The most critical material used in these transfer schemes is the dynamic release layer. It is coated on a temporary substrate and needs to realize two processes: chip pickup and chip release. First, it must pick up the chips peeled off from the source substrate using its own adhesion force. Then, under the action of laser, the dynamic release layer undergoes certain changes. The adhesion force decreases while generating a driving force, and the chips are released from the adhesion force. To achieve high yield, accuracy, and speed throughout the entire pick-up and release process, the selection of dynamic release layer materials is crucial.

[0003] Common dynamic release layer materials include metal films, polyimides, and triazine polymers. Among them, metal films belong to the direct decomposition type of laser ablation. The release mechanism is that under a laser of a certain wavelength and power, the metal film will be completely ablated and decomposed into metal fragments (Appl. Surf. Sci 186(2002)221-226), and the fragments generate a driving force that can transfer the core. However, this also brings serious fragment contamination.

[0004] Polyimide materials exhibit a bubbling effect at the interface caused by laser irradiation (ACS Appl. Mater. 12 (2020) 54230-54240). The mechanism involves laser irradiation of the shallow adhesive layer, causing it to decompose or melt, generating gas and forming bubbles. Changes in interface curvature reduce adhesion, and a transient impact provides kinetic energy for rotation, releasing the core particles. However, this type of bubbling material has a high decomposition temperature and requires a high ablation threshold.

[0005] Therefore, it is essential to provide a dynamic release layer material with high transfer yield. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a photosensitive composite material for laser-assisted MicroLED mass transfer, and the composite material provided by the present invention has a high transfer yield.

[0007] This invention proposes a composite material of random copolymers and photosensitive small molecules (such as azosulfone and tryptophan) suitable for laser-assisted mass transfer of Micro LEDs. By adjusting the types of monomers used in the polymerization, the mechanical and thermal properties of the random copolymer are modified, enabling the entire material to form a film. This film can be spin-coated onto a substrate to create a smooth and flat thin film, while also possessing high adhesion to facilitate the pickup of Micro LEDs during the transfer process. For example, in the synthesis of azosulfone small molecules from aniline and sodium methanesulfinate, adjusting the side chain groups on aniline allows it to selectively absorb different wavelengths of laser light used in the transfer process and decompose to generate volatile gases. Furthermore, by using a suitable synthetic route, the yield of the random copolymer and azosulfone small molecules can be improved, and the purification process can be simplified.

[0008] This invention provides a photosensitive composite material for laser-assisted MicroLED mass transfer, comprising: a random copolymer as shown in formula (I) and a photosensitive small molecule;

[0009]

[0010] The composite material of the present invention includes the random copolymer shown in formula (I).

[0011] Where a = 0.001 to 1, specifically 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 1; or any value between the two mentioned above;

[0012] b = 0.001 to 1, specifically 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 1; or any value between the two mentioned above.

[0013] c = 0.001 to 1; specifically, it can be 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 1; or any value between the two mentioned above.

[0014] The above ratio refers to the molar ratio of monomers. Specifically, a:b:c is (0.001~1):(0.001~1):(0.001~1); preferably, the molar ratio of a:b:c is (0.01~1):(0.01~1):(0.01~1).

[0015] In this invention, R1, R2, and R3 are independently selected from alkyl, hydrogen, cyano, halogen, hydroxyl, amino, aromatic, epoxy, carbonyl, nitro, sulfonic acid, sulfonyl, borane-substituted or unsubstituted C1-C50 alkyl, substituted or unsubstituted C1-C50 amide, substituted or unsubstituted C1-C50 ester, substituted or unsubstituted C1-C50 heteroaryl, substituted or unsubstituted C1-C50 aryloxy, and substituted or unsubstituted C1-C50 heterocyclic alkyl. The heteroatoms in the heteroaryl and heterocyclic alkyl groups are derived from one or more of O, S, and N.

[0016] According to the present invention, the random copolymer represented by formula (I) is obtained by reacting two or more monomers containing carbon-carbon double bonds, including the following specific monomer structures: styrene, N-phenylacrylamide, N-phenylmethylacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, 2-ethylhexyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, isophorone diamine, naphthalene diisocyanate, acrylamide, and methyl methacrylate, etc. Random copolymerization can be carried out through free radical addition. Besides free radical polymerization, other monomers can also be polymerized in different ways to form the polymer.

[0017] The monomer structure includes the following:

[0018]

[0019] The random copolymers of the present invention are randomly copolymerized from one or more of the aforementioned monomers via free radical addition. The R1, R2, and R3 groups are derived from the side chains of the monomers after free radical addition.

[0020] In some specific implementation schemes, it can be prepared from styrene, N-phenylacrylamide, and N-phenylmethylacrylamide; wherein the molar ratio of styrene, N-phenylacrylamide, and N-phenylmethylacrylamide is 5:4:1.

[0021] In some specific embodiments, it can be prepared from styrene, N-phenylacrylamide, and ethylene oxide-2-methacrylate; wherein the molar ratio of styrene, N-phenylacrylamide, and ethylene oxide-2-methacrylate is 5:4:1;

[0022] In some specific embodiments, it can be prepared from butyl acrylate, N-isopropylacrylamide, styrene, ethylene oxide-2-methyl methacrylate, 2-ethylhexyl methacrylate, and 2-(perfluorohexyl)ethyl methacrylate; wherein the molar ratio of butyl acrylate, N-isopropylacrylamide, styrene, ethylene oxide-2-methyl methacrylate, 2-ethylhexyl methacrylate, and 2-(perfluorohexyl)ethyl methacrylate is 15:15:10:5:3:2;

[0023] In some specific embodiments, it can be prepared from butyl acrylate, N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, and 2-(perfluorobutyl)ethyl methacrylate; wherein the molar ratio of butyl acrylate, N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, and 2-(perfluorobutyl)ethyl methacrylate is 1:1:2:1;

[0024] In some specific embodiments, it can be prepared from butyl acrylate, N-isopropylacrylamide, N-hydroxyethylacrylamide, and dimethylaminoethyl methacrylate; wherein the molar ratio of butyl acrylate, N-isopropylacrylamide, N-hydroxyethylacrylamide, and dimethylaminoethyl methacrylate is 2:6:1:1.

[0025] In some specific embodiments, it can be prepared from isophorone diamine and naphthalene diisocyanate; wherein the molar ratio of isophorone diamine to naphthalene diisocyanate is 1:1.

[0026] In some specific implementation schemes, butyl acrylate, ethylene oxide-2-methyl methacrylate, acrylamide, and methyl methacrylate are used to prepare the product; wherein the molar ratio of butyl acrylate, ethylene oxide-2-methyl methacrylate, acrylamide, and methyl methacrylate is 10:1:4:5.

[0027] The random copolymers represented by formula (I) of this invention have a weight-average molecular weight of 0.5 to 1,000,000.

[0028] The photosensitive composite material provided by this invention includes photosensitive small molecules.

[0029] According to the present invention, the photosensitive small molecule includes azo sulfone or tryptophan with the structure of formula (II);

[0030]

[0031] Wherein R is a C1-C20 alkyl group, C1-C20 alkynyl group, C1-C20 alkenyl group, halogen, C1-C20 alkoxy group, aryloxy group, aryl group, heterocyclic alkyl group, heteroaryl group, heteroaryloxy group, cyano group, carboxyl group, carbonyl group, nitro group, hydroxyl group, amino group, sulfonic acid group, sulfonyl group, phosphoric acid group, phosphoryl group, silyl group, or borane alkyl group with mono- or poly-substituted substituted groups. The heteroatoms in heteroaryl, heteroaryloxy, and heterocyclic alkyl groups are one or more of S, O, and N, and the halogens are one or more of Cl, F, I, and Br.

[0032] In some specific embodiments, the random copolymer represented by formula (I) has the following specific structure:

[0033] In some implementations of the present invention, the azo sulfone represented by formula (II) is...

[0034]

[0035]

[0036] In some specific implementations of the present invention, the azo sulfone represented by formula (II) has the following structure:

[0037]

[0038] According to the present invention, the mixing ratio of the polymer and the photosensitive small molecule is 500:1 to 1:500 (dry weight ratio).

[0039] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:500.

[0040] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:100.

[0041] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:50.

[0042] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:30.

[0043] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:10.

[0044] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:3.

[0045] In some specific embodiments, the polymer and the photosensitive small molecule are mixed in a ratio of 3:1.

[0046] The present invention provides a method for preparing a photosensitive composite material for laser-assisted MicroLED mass transfer, comprising the following steps:

[0047] A) Mix the polymer and solvent to obtain a polymer solution; mix the photosensitive small molecule and solvent to obtain a photosensitive small molecule solution;

[0048] B) Mix the polymer solution and the photosensitive small molecule solution to obtain the final product.

[0049] The method for preparing photosensitive composite materials for laser-assisted MicroLED mass transfer provided by the present invention first prepares a polymer.

[0050] The random copolymers of this invention are obtained by reacting two or more monomers containing carbon-carbon double bonds. The polymers of this invention are obtained by reacting two or more of the following: styrene, N-phenylacrylamide, N-phenylmethylacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, 2-ethylhexyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, isoflurane diamine, naphthalene diisocyanate, acrylamide, and methyl methacrylate.

[0051] The monomer and initiator were mixed, and dioxane was added to dissolve the mixture. The mixture was then stirred and heated in an oil bath under an inert gas atmosphere. After the reaction was complete, the product was precipitated in petroleum ether and dried to obtain the polymer product. The oil bath reaction temperature was 70°C, and the reaction time was 24 hours. This invention precipitates the product in petroleum ether because petroleum ether, as an organic solvent, is miscible with dioxane, and the polymer has poor solubility in petroleum ether, making it easy to precipitate. Furthermore, some unreacted monomer reactants can be dissolved and removed in petroleum ether.

[0052] In this invention, the initiator azobisisobutyronitrile decomposes to generate isobutyronitrile groups, which initiate a free radical reaction. Various monomers containing carbon-carbon double bonds undergo double bond addition, resulting in random copolymerization to generate a polymer.

[0053] This invention introduces an inert gas to remove water and oxygen, thus avoiding side reactions caused by the presence of oxygen and moisture.

[0054] In one specific embodiment of the present invention

[0055] 50 mmol of styrene, 40 mmol of N-phenylacrylamide, and 10 mmol of N-phenylmethylacrylamide were added sequentially to a flask. Then, 0.1 mmol of the initiator azobisisobutyronitrile was weighed and added directly to the flask. 60 ml of dioxane was added and stirred until the reactants were completely dissolved. A rubber stopper was placed over the flask, and the stopper was reinforced with several turns of wire. A short needle was inserted into one side of the top of the rubber stopper to connect the inside of the flask to the atmosphere. A long needle was inserted into the other side, ensuring it was below the liquid surface, and argon gas was introduced through the long needle. The mixture was stirred and ventilated for 15 minutes. After venting, the short needle was removed first, and petroleum jelly was quickly applied to the needle hole for sealing. The long needle was then removed, and the needle hole was sealed with petroleum jelly in the same way. The mixture was heated in an oil bath at 70°C with stirring for 24 hours. After the reaction was complete, the product was precipitated in petroleum ether and dried in an oven to obtain the polymer product.

[0056] Then, photosensitive small molecules are prepared; the preparation of photosensitive small molecules in this invention includes:

[0057] S1) Hydrochloric acid, water and p-phenoxyaniline are mixed, cooled in an ice-water bath and stirred to obtain the first solution; wherein, the ratio of hydrochloric acid, water and p-phenoxyaniline is 4.4 mL: 8.8 mL: 20 mmol; the addition of hydrochloric acid can maintain the reaction medium as strongly acidic, and can also react with sodium nitrite added later to generate nitrous acid.

[0058] Sodium nitrite is dissolved in water, cooled in an ice-water bath and stirred to obtain a second solution; the cooling time is 10 minutes; the amount of sodium nitrite added needs to be accurate and the dropping rate should not be too fast, so that sodium nitrite is involved in the entire reaction process and reacts with aromatic amines in a strong acid environment to form an azo amino compound.

[0059] Sodium methanesulfinate was dissolved in an organic solvent, cooled in ice water, and stirred to obtain a third solution.

[0060] The above steps require the reaction to be carried out at a low temperature in an ice-water bath because the diazotization reaction is very unstable, and a slightly higher temperature will cause side reactions and produce too many byproducts.

[0061] S2) The second solution is added dropwise to the first solution. After the addition is complete, a fourth solution is obtained. The addition time is 15 minutes.

[0062] The third solution was added dropwise to the fourth solution to obtain the fifth solution; the addition time was 10 minutes.

[0063] The added sodium methyl sulfinate will react with the previously generated diazonium salt, losing one mole of hydrogen halide to generate a small molecule of sulfazo.

[0064] S3) Add potassium carbonate solution dropwise to the fifth solution, adjust the pH to 9-10, stir the reaction at room temperature, and after the reaction is complete, extract the organic phase with dichloromethane, wash, dry, and distill under reduced pressure to obtain the final product.

[0065] The present invention adds a saturated potassium carbonate solution to adjust the solution from a strongly acidic environment to an alkaline environment because the reaction between sodium methanesulfonate and diazonium salt is difficult to carry out in an acidic environment, but can only be carried out smoothly in an alkaline environment. Moreover, the process of adjusting the pH needs to be slow. Too fast a dropping rate will cause the alkalinity of the solution to be too high in a local area, and the local reaction will be too fast, resulting in the formation of by-products.

[0066] The desired organic phase product is obtained by separating dichloromethane and deionized water because dichloromethane and deionized water have a sufficiently large density difference and are immiscible. During separation, the organic phase is in the upper layer and the aqueous phase is in the lower layer. The organic solvents dichloromethane and dioxane can be distilled off by vacuum distillation at 33-35℃. Finally, the solvent-free final product is obtained by vacuum drying.

[0067] In one specific embodiment of the present invention, the preparation of the photosensitive small molecule specifically includes:

[0068] 4.4 ml hydrochloric acid, 8.8 ml deionized water, and 20 mmol p-phenoxyaniline. Cool the round-bottom flask in an ice-water bath and stir for 10 minutes to obtain solution 1. Weigh 20 mmol sodium nitrite and dissolve it completely in deionized water. Cool and stir in an ice-water bath to obtain solution 2. Weigh 80 mmol sodium p-phenoxysulfinate and dissolve it in an organic solvent. Cool and stir in ice water to obtain solution 3. Slowly add small amounts of solution 2 to solution 1 dropwise using a dropper, maintaining an addition time of approximately 15 minutes. Immediately after adding solution 2, add solution 3 dropwise to solution 4 dropwise using a dropper to obtain solution 5. Maintain an addition time of approximately 10 minutes. Weigh excess potassium carbonate and dissolve it in deionized water to obtain a saturated solution. Cool and stir in an ice-water bath. Add small amounts of potassium carbonate solution to solution 5 dropwise using a dropper, observing and recording the color and state changes. Measure the pH value of the solution with pH paper after each drop is added, until the solution becomes alkaline, with a pH value of approximately 9-10. The ice-water bath was then removed, and solution 5 was stirred at room temperature for 2 hours. After the reaction was complete, dichloromethane was added for liquid-liquid extraction to obtain the organic phase, which was then washed with deionized water 2-3 times. An appropriate amount of anhydrous sodium sulfate was added to the separated organic phase, and the mixture was allowed to stand and dry. The sodium sulfate was then filtered off to obtain the dehydrated organic phase.

[0069] The organic phase was poured into a spherical flask and subjected to vacuum distillation to remove the organic solvent. The flask was then placed in a vacuum drying oven to dry the final product, which was an orange-red powder.

[0070] The polymer and solvent are mixed to obtain a polymer solution; the photosensitive small molecule and solvent are mixed to obtain a photosensitive small molecule solution; the solvent is dioxane.

[0071] The polymer solution and the photosensitive small molecule solution are mixed to obtain the final product.

[0072] The mixing ratio of the polymer and the photosensitive small molecule described in this invention is 500:1 to 1:500 (dry weight ratio). The mass ratio of the two has been clearly described above and will not be repeated here.

[0073] This invention provides a laser-assisted mass transfer method for MicroLEDs, using the composite material described in any one of the above technical solutions as a dynamic release layer.

[0074] This invention also provides the application of the above-mentioned composite material as a dynamic release layer in laser-assisted MicroLED mass transfer.

[0075] The process verification of the present invention specifically includes:

[0076] The prepared solution is uniformly spin-coated onto a sapphire substrate to form a smooth, uniform adhesive layer. In the first transfer step, the MicroLED chip is peeled off the original substrate. The temporary substrate coated with the composite adhesive layer has strong adhesion, allowing the chip to be picked up intact. In the second transfer step, a laser is applied to the adhesive layer. The small molecules absorb the 355nm wavelength laser, resulting in complete ablation through photolysis and pyrolysis. The generated volatile gases produce a driving force that releases the MicroLED chip.

[0077] When a small sulfone molecule absorbs a 355nm wavelength laser, it undergoes a π→π* transition and further interstitial crossing, being excited from a singlet state to a triplet state to generate an aryl cation, which further decomposes to generate volatile nitrogen gas.

[0078] This scheme focuses on preparing an ablation-type polymer-sulfone azo composite material suitable for laser-assisted MicroLED mass transfer. The novel transfer composite material is prepared by mixing the polymer and sulfone azo molecules in a specific ratio. The mechanical and thermal properties of the polymer portion can be adjusted by simply changing the type of comonomer, resulting in high adhesion, spin-coating into a smooth film, and providing the overall network framework for the film layer. The sulfone azo molecule, as the photosensitive component, has its properties adjusted by changing the type of side chain groups on the aniline raw material, enabling it to selectively absorb different wavelengths of laser light. This results in the decomposition of the molecule into a large amount of gas, generating a driving force for core transfer. Optimization of the synthesis steps improves the yield of both the polymer and the small molecule without requiring complex subsequent purification steps. Currently, the core pick-up step achieves a yield of over 99%, and the core release step achieves complete release in a small area.

[0079] The material prepared by this invention has high adhesion, good film-forming properties (smooth and flat without bubbles or pinholes), and high wavelength selective absorption (absorbance at 355nm is 12 times that at 266nm).

[0080] This invention optimizes the optical, mechanical, and thermal properties of the overall material by adjusting the types and structures of the raw materials for synthesizing the polymer and the azo sulfone small molecule. The synthesis steps are simple and do not require complex purification procedures, making it convenient to meet different process verification requirements. The polymer component possesses high adhesion to facilitate core particle pickup. The azo sulfone small molecule has a rapid photolysis rate to generate gas that drives the release of the core particle.

[0081] The evidence collection method of the present invention includes:

[0082] Nanoindentation characterizes the hardness and elastic modulus of materials after film formation. A universal testing machine characterizes the adhesion force of materials. Ultraviolet spectrophotometer characterizes absorbance changes, and laser ablation verifies process yield. Attached Figure Description

[0083] Figure 1 A schematic diagram illustrating the role of the transfer adhesive containing the composite material of this invention in the mass transfer of MicroLEDs;

[0084] Figure 2 A microscope image of the MicroLED mass transfer and peeling effect provided in Embodiment 1 of this application;

[0085] Figure 3 Microscopic photograph of the mass transfer and release effect of MicroLED provided in Embodiment 1 of this application;

[0086] Figure 4 Molecular weight measurement of the random polymer provided in Example 1 of this application;

[0087] Figure 5 The 1H NMR spectrum of the p-phenoxyazosulfone small molecule provided in Example 1 of this application;

[0088] Figure 6 This is a schematic diagram showing the hardness values ​​of the adhesive layer after film formation of the composite material provided in Examples 1, 2, and 3 of this application.

[0089] Figure 7 This is a schematic diagram showing the elastic modulus values ​​of the adhesive layer after the composite material film is formed, as provided in Examples 1, 2, and 3 of this application.

[0090] Figure 8 The UV spectrum of the p-methoxyazosulfone small molecule in Example 2 of this application shows that it has high wavelength selective absorption at different wavelengths;

[0091] Figure 9 Photograph showing the composite material in Example 2 of this application exhibiting good film-forming properties;

[0092] Figure 10 The images show the UV absorbance spectra of the p-phenoxyazosulfone small molecule in Example 1 of this application under different light irradiation times (365 nm), demonstrating that the small molecule has rapid photolysis capability.

[0093] Figure 11 The 1H NMR spectra of the p-methoxyazosulfone small molecule provided in Examples 2 and 3 of this application are shown.

[0094] Figure 12 The 1H NMR spectrum of the trifluoromethylazosulfone small molecule provided in Example 5 of this application;

[0095] Figure 13 The 1H NMR spectrum of the o-methoxyazosulfone small molecule provided in Example 5 of this application;

[0096] Figure 14 The 1H NMR spectrum of the o-chloroazosulfone small molecule provided in Example 6 of this application is shown. Detailed Implementation

[0097] This invention provides a photosensitive composite material for laser-assisted MicroLED mass transfer, its preparation method, and its application. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and fall within the scope of this invention. The method and application of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the method and application described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0098] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0099] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0100] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0101] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0102] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0103] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0104] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means an actual value within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range.

[0105] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0106] The embodiments and comparative examples of this invention describe some examples, in which the embodiments illustrate certain implementations of the invention. However, this does not mean that the effects of the invention can only be achieved in these examples.

[0107] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a photosensitive composite material for laser-assisted MicroLED mass transfer, its preparation method, and its application.

[0108] Example 1

[0109]

[0110]

[0111] The synthesis steps of polymer-azosulfone small molecule composite materials are as follows:

[0112] Step 1: Polymer synthesis is performed first. 50 mmol of styrene, 40 mmol of N-phenylacrylamide, and 10 mmol of N-phenylmethylacrylamide are added to the flask in sequence, and then 0.1 mmol of the initiator azobisisobutyronitrile is weighed and added directly to the flask as well.

[0113] Step 2: Add 60ml of dioxane and stir to completely dissolve the above reactants.

[0114] Step 3: Add a rubber stopper to the bottle mouth and turn it upside down, then wrap the bottle mouth with wire several times to reinforce it.

[0115] Step 4: Insert a short needle into one side of the top of the rubber stopper to connect the inside of the bottle with the atmosphere. Insert a long needle into the other side, ensuring the needle is below the liquid surface, and introduce argon gas through the long needle. Stir and ventilate for 15 minutes.

[0116] Step 5: After ventilation is complete, first remove the short needle and quickly apply Vaseline to the needle hole to seal it. Then remove the long needle and seal the needle hole with Vaseline in the same way.

[0117] Step 6: Heat in an oil bath at 70°C with stirring for 24 hours.

[0118] Step 7: After the reaction is complete, precipitate in petroleum ether to obtain the precipitated product, and dry in an oven to obtain the polymer product.

[0119] Step 8: Proceed with the synthesis of azosulfone small molecules. Add 4.4 ml of hydrochloric acid, 8.8 ml of deionized water, and 20 mmol of p-phenoxyaniline sequentially to a round-bottom flask. Cool the round-bottom flask in an ice-water bath and stir for 10 minutes to obtain solution 1.

[0120] Step 9: Weigh 20 mmol of sodium nitrite and dissolve it completely in deionized water. Cool the solution in an ice-water bath and stir to obtain solution 2.

[0121] Step 10: Weigh 80 mmol of sodium p-phenoxysulfinate and dissolve it in an organic solvent. Cool the solution in ice water and stir to obtain solution 3.

[0122] Step 11: Use a dropper to slowly add a small amount of solution 2 to solution 1 each time, keeping the addition time at about 15 minutes.

[0123] Step 12: Immediately after adding solution 2, use a dropper to add solution 3 dropwise to solution 4 to obtain solution 5. The addition time should be kept at approximately 10 minutes.

[0124] Step 13: Weigh out excess potassium carbonate and dissolve it in deionized water to obtain a saturated solution. Cool the solution in an ice-water bath and stir.

[0125] Step Fourteen: Use a dropper to add a small amount of potassium carbonate solution to solution 5 each time, observe and record the changes in the color and state of the solution. Measure the pH value of the solution with pH paper after each drop is added, until the solution becomes alkaline and the pH value is around 9-10.

[0126] Step 15: Then remove the ice water bath and let solution 5 be stirred at room temperature for 2 hours.

[0127] Step 16: After the reaction is complete, add dichloromethane to extract the organic phase by liquid-liquid extraction, and wash with deionized water 2-3 times.

[0128] Step 17: Add an appropriate amount of anhydrous sodium sulfate to the separated organic phase, let it stand and dry, and filter out the sodium sulfate to obtain the dehydrated organic phase.

[0129] Step 18: Pour the organic phase into a spherical flask and perform vacuum distillation to remove the organic solvent. Then, place it in a vacuum drying oven to dry the final product, which is an orange-red powder.

[0130] Step 19: Preparation of polymer-sulfone small molecule composite material. Weigh a certain amount of the dried polymer product, add dioxane, and shake to mix well to obtain a gel-like polymer solution with a concentration of 0.25 g to 0.5 g / ml.

[0131] Step 20: Weigh a certain amount of dry sulfazo powder, dissolve it completely in dioxane, and prepare a solution with a concentration of 1 g / ml.

[0132] Step 21: Mix the gel-like polymer solution and the p-phenoxyazosulfone small molecule solution at a ratio of 3:1 (dry weight) to obtain the final composite material. Let it stand for later use.

[0133] Step 22: Process Validation. The prepared solution is uniformly spin-coated onto the sapphire substrate to form a smooth, uniform adhesive layer. In the first transfer step, the MicroLED chip is peeled off from the original substrate. The temporary substrate coated with the composite adhesive layer has strong adhesion, allowing the chip to be picked up intact. In the second transfer step, a laser is applied to the adhesive layer. Small molecules absorb the 355nm wavelength laser, resulting in complete ablation through photolysis and pyrolysis. The generated volatile gases produce a driving force that releases the MicroLED chip.

[0134] The results are as follows Figures 2-4 As shown, where Figure 2 Microscopic images showing the peeling yield >99%; Figure 3 To release photos of results with 100% yield; Figure 4 To obtain the polymer spectrum, it can be seen that the molecular weight of the obtained polymer is: Mn.=73543Mw.=149622Mp.=96306PDI=2.034489.

[0135] Figure 5 The 1H NMR spectrum of the prepared azosulfone small molecule is shown below: 1H NMR (400MHz, CDCl3) δ 7.95, 7.94, 7.93, 7.93, 7.46, 7.44, 7.43, 7.28, 7.28, 7.26, 7.25, 7.13, 7.11, 7.11, 7.09, 7.09, 7.07, 7.07, 3.19, 2.04, 1.59, 1.26.

[0136] Figure 6 The image shows the UV-Vis spectrum of the synthesized azo sulfone small molecule.

[0137] Example 2

[0138]

[0139] Polymer-sulfone small molecule composites:

[0140] Step 1: Polymer Synthesis. Styrene, N-phenylacrylamide, and methyl ethylene oxide-2-methacrylate are mixed and dissolved in a ratio of 5:4:1 with the initiator azobisisobutyronitrile (AIBN) for copolymerization. Alternatively, the ratio of styrene to N-phenylacrylamide in the comonomers can be adjusted, ranging from 8:1 to 1:8. Or, an equal amount of N-phenylacrylamide can be completely replaced with styrene.

[0141] Step 2: Composite Material. The polymer was dissolved in dioxane to prepare a gel solution with a concentration of 0.5 g / ml. The p-methoxyazosulfone small molecule was dissolved in dioxane to prepare a solution with a concentration of 1 g / ml. The polymer solution and the p-methoxyazosulfone small molecule solution were thoroughly mixed at ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coated, and prepared as wafers for process verification.

[0142] Figure 11 The 1H NMR spectrum of the prepared p-methoxyazosulfone small molecule is shown below: 1H NMR (400MHz, CDCl3) δ 7.96, 7.94, 7.05, 7.03, 3.94, 3.19.

[0143] Example 3

[0144]

[0145] Polymer-sulfone small molecule composites:

[0146] Step 1: Polymer Synthesis. Butyl acrylate, N-isopropylacrylamide, styrene, ethylene oxide-2-methyl methacrylate, 2-ethylhexyl methacrylate, and 2-(perfluorohexyl)ethyl methacrylate are mixed and copolymerized with an initiator in a ratio of 15:15:10:5:3:2. Furthermore, while keeping the total feed amount constant, the ratio of butyl acrylate:N-isopropylacrylamide:styrene can be adjusted, for example, to 5:15:20, 20:15:5, etc.

[0147] Step 2: Composite Material. The polymer was dissolved in dioxane to prepare a gel solution with a concentration of 0.5 g / ml. The p-methoxyazosulfone small molecule was dissolved in dioxane to prepare a solution with a concentration of 1 g / ml. The polymer solution and the p-methoxyazosulfone small molecule solution were thoroughly mixed at ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coated, and prepared as wafers for process verification.

[0148] The above polymers and different types of small molecules were mixed in different proportions to prepare wafers for process verification.

[0149] Figure 11 The 1H NMR spectrum of the prepared p-methoxyazosulfone small molecule is shown below: 1H NMR (400MHz, CDCl3) δ 7.96, 7.94, 7.05, 7.03, 3.94, 3.19.

[0150] Example 4

[0151]

[0152] Polymer-sulfone small molecule composites:

[0153] Step 1: Polymer Synthesis. Butyl acrylate, N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, and 2-(perfluorobutyl)ethyl methacrylate are mixed and copolymerized in a ratio of 1:1:2:1, or N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, and trifluoroethyl acrylate are mixed in a ratio of 4:4:1:1, along with an initiator.

[0154] Step 2: Composite Materials. The polymer was dissolved in dioxane to prepare a gel solution with a concentration of 0.5 g / ml. The benzidine azo sulfone small molecule was dissolved in dioxane to prepare a solution with a concentration of 1 g / ml. The polymer solution and the benzidine azo sulfone small molecule solution were thoroughly mixed at ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coated, and prepared as wafers for process verification.

[0155] Example 5

[0156]

[0157] Polymer-sulfone small molecule composites:

[0158] Step 1: Polymer Synthesis. Three to four of the following are copolymerized in different proportions: butyl acrylate, N-isopropylacrylamide, N-hydroxyethylacrylamide, and dimethylaminoethyl methacrylate. For example, butyl acrylate:N-isopropylacrylamide:N-hydroxyethylacrylamide:dimethylaminoethyl methacrylate = 2:6:1:1, or butyl acrylate:N-hydroxyethylacrylamide:dimethylaminoethyl methacrylate = 2:2:1, or N-isopropylacrylamide:N-hydroxyethylacrylamide:dimethylaminoethyl methacrylate = 8:1:1, etc.

[0159] Step 2: Composite Material. The polymer was dissolved in dioxane to prepare a gel solution with a concentration of 0.5 g / ml. o-Methoxyazosulfone and p-trifluoromethyl azosulfone were dissolved separately in dioxane to prepare solutions with a concentration of 1 g / ml. The o-Methoxyazosulfone and p-trifluoromethyl azosulfone solutions were then mixed in ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4. The polymer solution and the mixed azosulfone solution were then thoroughly mixed in ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coated, and prepared as wafers for process verification.

[0160] Figure 12 The 1H NMR spectrum of the prepared p-trifluoromethylazosulfone small molecule; 1 H NMR (400MHz, CDCl3) δ8.07,8.05,7.87,7.85,3.26.

[0161] Figure 13 The 1H NMR spectrum of the prepared o-methoxyazosulfone small molecule is shown below: 1H NMR (400MHz, CDCl3) δ 7.66, 7.64, 7.57, 7.55, 7.53, 7.06, 7.04, 6.97, 6.96, 6.94, 3.93, 3.13.

[0162] Example 6

[0163]

[0164] Polymer-sulfone small molecule composites:

[0165] Step 1: Polymer Synthesis. Isoflurane diamine and naphthalene diisocyanate were dissolved separately in dioxane, rapidly mixed, and heated at 100°C for 20 hours. The product was precipitated in petroleum ether and dried. Step 2: Composite Material. The above polymer was dissolved in dioxane to prepare a gel solution with a concentration of 0.5 g / ml. o-chloroazosulfone small molecules were dissolved in dioxane to prepare a solution with a concentration of 1 g / ml. The polymer solution and the o-chloroazosulfone small molecule solution were thoroughly mixed at ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coated, and prepared as wafers for process verification.

[0166] Figure 14 The hydrogen NMR spectrum of the prepared o-chloroazosulfone small molecule; 1 H NMR (400MHz, CDCl3) δ7.78,7.76,7.65,7.63,7.62,7.60,7.43,7.41,7.39,7.26,3.23.

[0167] Example 7

[0168]

[0169] Polymer-sulfone small molecule composites:

[0170] Step 1: Polymer Synthesis. Three to four of the following are copolymerized in different proportions: butyl acrylate, ethylene oxide-2-methyl methacrylate, acrylamide, and methyl methacrylate. For example, butyl acrylate:ethylene oxide-2-methyl methacrylate:acrylamide:methyl methacrylate = 10:1:4:5, butyl acrylate:ethylene oxide-2-methyl methacrylate:acrylamide = 5:1:4, etc.

[0171] Step 2: Composite Material. The polymer was dissolved in dioxane to prepare a gel solution with a concentration of 0.5 g / ml. The triazine small molecule synthesized from diazotized 4,4-diaminodiphenyl ether and N-methylethanolamine was dissolved in dioxane (the synthesis steps are the same as for the azo sulfone small molecule) to prepare a solution with a concentration of 1 g / ml. The polymer solution and the triazine small molecule solution were thoroughly mixed at ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coated, and prepared as wafers for process verification.

[0172] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A photosensitive composite material for laser-assisted MicroLED mass transfer, characterized in that, include: The random copolymer and photosensitive small molecule shown in formula (I); the dry weight ratio of the random copolymer and the photosensitive small molecule is 4:1 to 1:4; Formula (I); Wherein, a = 0.001~1, b = 0.001~1, c = 0.001~1; R1, R2 and R3 are independently selected from alkyl, hydrogen, cyano, halogen, hydroxyl, amino, aromatic, epoxy, carbonyl, nitro, sulfonic acid, sulfonyl, boroalkyl-substituted C1~C50 alkyl, substituted or unsubstituted C1~C50 amide, substituted or unsubstituted C1~C50 ester, substituted or unsubstituted C1~C50 heteroaryl, substituted or unsubstituted C1~C50 aryloxy, substituted or unsubstituted C1~C50 heterocyclic alkyl; The photosensitive molecule is an azo sulfone of formula (II); Formula (II); Wherein R is a benzene ring with hydrogen at the 2-6 substitution positions, a C1-C20 alkyl group, a C1-C20 alkynyl group, a C1-C20 alkenyl group, a halogen, a C1-C20 alkoxy group, an aryloxy group, an aryl group, a heterocyclic alkyl group, a heteroaryl group, a heteroaryloxy group, a cyano group, a carboxyl group, a carbonyl group, a nitro group, a hydroxyl group, an amino group, a sulfonic acid group, a sulfonyl group, a phosphoric acid group, a phosphoryl group, a silyl group, or a boroalkyl group with mono- or poly-substituted alkyl groups.

2. The photosensitive composite material according to claim 1, characterized in that, The random copolymer represented by formula (I) is obtained by reacting two or more compounds containing carbon-carbon unsaturated double bonds; the compounds containing carbon-carbon unsaturated double bonds include two or more of styrene, N-phenylacrylamide, N-phenylmethylacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, 2-ethylhexyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, acrylamide and methyl methacrylate.

3. A photosensitive composite material for laser-assisted MicroLED mass transfer, characterized in that, include: The random copolymer and photosensitive small molecule have the following structure; the dry weight ratio of the random copolymer and the photosensitive small molecule is 4:1 to 1:

4. Formula (I-1); Formula (I-2); Formula (I-3); Formula (I-4); Formula (I-5); Formula (I-6): The photosensitive molecule is an azo sulfone of formula (II); Formula (II); Wherein R is a benzene ring with hydrogen at the 2-6 substitution positions, a C1-C20 alkyl group, a C1-C20 alkynyl group, a C1-C20 alkenyl group, a halogen, a C1-C20 alkoxy group, an aryloxy group, an aryl group, a heterocyclic alkyl group, a heteroaryl group, a heteroaryloxy group, a cyano group, a carboxyl group, a carbonyl group, a nitro group, a hydroxyl group, an amino group, a sulfonic acid group, a sulfonyl group, a phosphoric acid group, a phosphoryl group, a silyl group, or a boroalkyl group with mono- or poly-substituted alkyl groups.

4. The photosensitive composite material according to claim 1 or 2, characterized in that, The azo sulfone represented by formula (II) is Equation (II-1) Equation (II-2); Formula (II-3); Equation (II-4); Equation (II-5); Equation (II-6); Equation (II-7).

5. The photosensitive composite material according to claim 1 or 2, characterized in that, The azo sulfone represented by formula (II) has the following structure: 。 6. A method for preparing a photosensitive composite material for laser-assisted MicroLED mass transfer according to claim 1, comprising the following steps: A) Mix the random copolymer with a solvent to obtain a polymer solution; mix the photosensitive small molecule with a solvent to obtain a photosensitive small molecule solution; B) Mix the polymer solution and the photosensitive small molecule solution to obtain the final product.

7. The preparation method according to claim 6, characterized in that, The solvent is dioxane.

8. The preparation method according to claim 6, characterized in that, The method for preparing the random copolymer includes: It is obtained by reacting two or more compounds containing carbon-carbon unsaturated double bonds; the compounds containing carbon-carbon unsaturated double bonds include two or more of styrene, N-phenylacrylamide, N-phenylmethylacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, 2-ethylhexyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, acrylamide, and methyl methacrylate.

9. The preparation method according to claim 6, characterized in that, The preparation method of the photosensitive small molecule includes: S1) Hydrochloric acid, water and p-phenoxyaniline are mixed, cooled in an ice-water bath and stirred to obtain the first solution; S2) The second solution is added dropwise to the first solution. After the addition is complete, a fourth solution is obtained. The addition time is 15 minutes. S3) Add potassium carbonate solution dropwise to the fifth solution, adjust the pH to 9-10, stir the reaction at room temperature, and after the reaction is complete, extract the organic phase with dichloromethane, wash, dry, and distill under reduced pressure to obtain the final product.

10. A method for laser-assisted mass transfer of MicroLEDs, characterized in that, The composite material described in any one of claims 1 to 5 is used as the dynamic release layer.

11. The application of the composite material according to any one of claims 1 to 5 as a dynamic release layer in laser-assisted MicroLED mass transfer.

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