Packaging substrate and method for manufacturing the same

Abstract

The application provides a packaging substrate and a preparation method thereof. The preparation method comprises the following steps: preparing a semi-cured substrate, the semi-cured substrate comprising a first surface and a second surface arranged oppositely; introducing a cross-linkable monomer into the semi-cured substrate, the cross-linkable monomer penetrating through a side of the first surface facing the second surface, and the cross-linkable monomer being cross-linked in situ in the semi-cured substrate; introducing a plasticizer into the semi-cured substrate after the cross-linkable monomer is introduced, the plasticizer penetrating through a side of the second surface facing the first surface; and performing a drying treatment on the semi-cured substrate after the cross-linkable monomer and the plasticizer are introduced, so as to obtain the packaging substrate. The packaging substrate and the preparation method thereof provided by the application introduce the plasticizer and the cross-linking molecule into the semi-cured substrate on two sides respectively, realize wide-range regulation of static and dynamic mechanical properties, develop a longitudinal selected-area packaging substrate with high precision and a wide range, and realize consideration of the mechanical regulation range and the diffusion control precision in a limited vertical space.

Description

Technical Field

[0001] This application belongs to the field of electronic packaging technology, and in particular relates to a packaging substrate and its preparation method. Background Technology

[0002] Flexible bioelectronic systems can conformally fit biological tissues, making them valuable for applications in health monitoring and medical diagnosis. These devices integrate sensing units, electrodes, and other functional components onto a flexible packaging substrate, relying on the substrate's adhesion to biological tissue to acquire physiological signals. Due to the significant differences in mechanical properties between electronic components and biological tissues, the static and dynamic mechanical properties of the packaging substrate directly affect the device's signal fidelity and operational stability.

[0003] Currently, the main methods for controlling the mechanical properties of encapsulation substrates include chemical synthesis and physical intercalation, which can only achieve modulus control in the horizontal direction. Existing control methods have poor adaptability and cannot meet the asymmetric mechanical matching requirements under dynamic service conditions. Physical intercalation is prone to interlayer delamination, while chemical control methods suffer from defects such as interfacial diffusion, insufficient control precision, and uncontrollable penetration depth. They cannot simultaneously achieve a wide range of mechanical control and precise diffusion control within a limited vertical space, indicating significant limitations of current technologies. In conclusion, current encapsulation substrates are insufficient to meet current production needs. Summary of the Invention

[0004] In view of this, embodiments of this application provide a packaging substrate and its preparation method to solve the technical problem that existing packaging substrates cannot simultaneously achieve mechanical control range and diffusion control precision within a limited vertical space, and thus cannot meet current production needs.

[0005] In a first aspect, embodiments of this application provide a method for preparing an encapsulation substrate, comprising the following steps: A semi-cured substrate is prepared, the semi-cured substrate comprising a first surface and a second surface disposed opposite to each other; A crosslinkable monomer is introduced into the semi-cured substrate, the crosslinkable monomer permeates through the first surface toward the second surface, and the crosslinkable monomer crosslinks in situ within the semi-cured substrate; A plasticizer is introduced into a semi-cured substrate after the introduction of a crosslinkable monomer, the plasticizer penetrating through the second surface toward the first surface; The semi-cured substrate after the introduction of the crosslinkable monomer and the plasticizer is dried to obtain the encapsulation substrate.

[0006] In some embodiments, the introduction of a crosslinkable monomer into the semi-cured substrate, wherein the crosslinkable monomer permeates through the first surface toward the second surface, and the crosslinkable monomer crosslinks in situ within the semi-cured substrate, includes: Provide organic solvents and crosslinkable monomers; The crosslinkable monomer is dissolved in the organic solvent to prepare a first permeation solution; The first permeation solution is evenly dripped onto the first surface; The first surface and the first permeation solution located on the first surface are sealed, and the crosslinkable monomer permeates through the first surface toward the second surface. In-situ photopolymerization and crosslinking of crosslinkable monomers that have penetrated into the semi-cured substrate are performed using a UV curing lamp with a preset wavelength and power.

[0007] In some embodiments, the crosslinkable monomer includes at least one of methyl methacrylate, 1,6-hexanediol dimethacrylate, 1,12-dodecyl dimethacrylate, and bisphenol A dimethacrylate.

[0008] In some embodiments, the organic solvent includes at least one of toluene, cyclohexane, xylene, and tetrahydrofuran.

[0009] In some embodiments, the concentration of the first permeation solution is 200~6000 mg / mL.

[0010] In some embodiments, introducing a plasticizer into a semi-cured substrate after the introduction of a crosslinkable monomer, wherein the plasticizer penetrates through the second surface toward the first surface, includes: Provide the organic solvent and plasticizer; The plasticizer is dissolved in the organic solvent to prepare a second permeation solution; The second permeation solution is evenly dripped onto the second surface; The second surface and the second permeation solution located on the second surface are sealed to allow the plasticizer to permeate through the second surface toward one side of the first surface.

[0011] In some embodiments, the plasticizer includes at least one of polyisobutylene oligomer, silanized polybutene, squalane, and white oil.

[0012] In some embodiments, the concentration of the second permeation solution is 200~6000 mg / mL.

[0013] In some embodiments, the preparation of the semi-cured substrate includes: Provides polymers and organic solvents; The polymer is dissolved in the organic solvent and stirred under preset conditions to obtain a transparent and clear polymer solution; The polymer solution is placed in a closed environment at a preset temperature, and the semi-cured substrate is obtained after the solvent evaporates.

[0014] In some embodiments, the preparation of the semi-cured substrate includes: Provide polymers and crosslinking agents; The polymer and the crosslinking agent are mixed uniformly at a preset temperature and a preset shear rate to obtain a blend. The blend is compressed into tablets to obtain the semi-cured substrate; or, The polymer is blended with a crosslinking agent, or the polymer, crosslinking agent and initiator are blended in solution. After film formation, the semi-cured substrate is obtained by controlling the UV exposure dose (time / intensity) or the heat treatment step time.

[0015] In some embodiments, the polymer includes at least one of styrene-butadiene-styrene block copolymer, styrene-isobutylene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, polyurethane, and polyisobutylene.

[0016] In some embodiments, before introducing the crosslinkable monomer into the semi-cured substrate after obtaining the semi-cured substrate, the method includes: The physical mask is placed on the first and second surfaces of the semi-cured substrate, and the three are precisely aligned. Subsequently, the above components are placed under a vacuum press to apply pressure, ensuring that the mask plate and the semi-cured substrate are tightly bonded without gaps.

[0017] Secondly, this application provides an encapsulation substrate prepared using the preparation method described in the first aspect.

[0018] The encapsulation substrate and its preparation method provided in this application introduce crosslinkable monomers and plasticizers stepwise from both sides of the semi-cured substrate, controlling their penetration from different sides to the other side. This achieves a longitudinal component gradient distribution within the semi-cured substrate, thereby enabling gradient regulation of longitudinal mechanical properties. It can simultaneously achieve wide-scale mechanical regulation and high-precision diffusion control within a vertical space of hundreds of micrometers, avoiding the problem of heterogeneous layer delamination. It has the advantages of being able to achieve wide-scale longitudinal mechanical regulation of the encapsulation substrate within a vertical space of hundreds of micrometers, while ensuring high-precision diffusion control, avoiding interlayer delamination, improving the decoupling and matching ability of the encapsulation substrate to heterogeneous interfaces, and meeting the asymmetric mechanical matching requirements of flexible electronic functional components and biological tissues. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart of the method for preparing the packaging substrate provided in the embodiments of this application; Figure 2 This is a performance test diagram of the packaging substrate provided in the embodiments of this application. Detailed Implementation

[0021] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that the embodiments of this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the embodiments of this application with unnecessary detail.

[0022] It should also be understood that the term "and / or" as used in the specification of embodiments of this application and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] Furthermore, in the description of the embodiments and the appended claims of this application, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0026] In the description of embodiments in this application, references to "some embodiments" or "some embodiments" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in some embodiments," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiments, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" refers to two or more.

[0027] It should be noted that the Chinese translations of the English words appearing throughout the text are shown in the table below:

[0028] In flexible bioelectronic systems, the design of the longitudinal mechanical properties of the packaging substrate faces challenges. Existing horizontal control methods cannot be directly applied to vertical designs. Physical embedding methods are prone to interlayer delamination due to abrupt modulus changes at heterogeneous interfaces. While chemical control methods based on component infiltration can broaden the range of mechanical control, solution diffusion at the boundary leads to reduced interface precision. When high-content modified components are introduced to meet the differences in mechanical properties between the upper and lower surfaces, uncontrolled infiltration depth causes interface diffusion, blurring the pre-set mechanical gradient boundary and ultimately weakening the substrate's ability to decouple and match heterogeneous interfaces. This problem directly affects the system's signal fidelity and service life, manifesting as decreased signal quality and reduced device reliability.

[0029] If these issues are not addressed, the packaging substrate will be unable to maintain an asymmetric mechanical fit with biological tissue under dynamic service conditions, leading to a continuous deterioration in signal fidelity. This will consequently affect the accuracy of medical diagnostics and shorten device lifespan. In long-term use, interface failure may trigger complete system failure, posing a risk to health monitoring and medical diagnostic applications.

[0030] In this regard, firstly, such as Figure 1 As shown, this application proposes a method for preparing an encapsulation substrate, comprising the following steps: S10. Prepare a semi-cured substrate, the semi-cured substrate including a first surface and a second surface disposed opposite to each other; S20. Introduce a crosslinkable monomer into the semi-cured substrate. The crosslinkable monomer penetrates through the first surface toward the second surface and crosslinks in situ within the semi-cured substrate. S30. A plasticizer is introduced into the semi-cured substrate after the introduction of the crosslinkable monomer, and the plasticizer penetrates through the second surface toward the first surface. S40. The semi-cured substrate after the introduction of crosslinkable monomers and plasticizers is dried to obtain the encapsulation substrate.

[0031] By introducing crosslinkable monomers and plasticizers stepwise from both sides of a semi-cured substrate, and controlling their penetration from different sides to the other, a longitudinal component gradient distribution is achieved within the semi-cured substrate. This enables gradient regulation of longitudinal mechanical properties, allowing for simultaneous wide-scale mechanical regulation and high-precision diffusion control within a vertical space of hundreds of micrometers. This avoids the problem of heterogeneous layer delamination and offers advantages such as achieving wide-scale longitudinal mechanical regulation of the encapsulation substrate within a vertical space of hundreds of micrometers, while ensuring high-precision diffusion control, preventing layer delamination, and enhancing the decoupling and matching capabilities of the encapsulation substrate for heterogeneous interfaces. This meets the asymmetric mechanical matching requirements of flexible electronic functional components and biological tissues.

[0032] This application achieves wide-range control over the static and dynamic mechanical properties of a semi-cured substrate by in-situ permeation of plasticizers and crosslinkable molecules into the substrate, inducing a conformational change in the substrate's molecular chains. Furthermore, by controlling the degree of curing (semi-curing) of the substrate, this application alters the diffusion mode of the permeated components, changing it from free diffusion to confined diffusion, thereby enabling precise control over the spatial variation of mechanical properties. Specifically, plasticizers and crosslinking molecules are introduced on both sides of the semi-cured substrate to achieve wide-range control over static and dynamic mechanical properties, resulting in a high-precision, wide-range longitudinal selective encapsulation substrate for the research and development and manufacturing of flexible bioelectronic systems.

[0033] For ease of understanding, the following explains some key terms in this embodiment: Encapsulation substrate: This generally refers to the material layer used to support and protect electronic components and provide an interface with the external environment. In flexible bioelectronic systems, the substrate needs to possess good flexibility, biocompatibility, and specific mechanical properties to achieve conformal adhesion to biological tissues and signal transmission.

[0034] Semi-cured substrate: The "semi-cured" state here refers to a loose, three-dimensional confined network formed by polymer segments through physical entanglement or initial weak chemical cross-linking. Retaining a moderate amount of free volume and incompletely shrunken molecular chains is crucial for providing a "confined diffusion" physical pathway for subsequent infiltration steps. The semi-cured substrate includes a first surface and a second surface arranged opposite each other, which serve as the starting interface for the subsequent introduction of different modifying components.

[0035] Crosslinkable monomers refer to small molecule compounds containing functional groups that can undergo polymerization or crosslinking reactions. When crosslinkable monomers are introduced into a semi-cured substrate, they can undergo chemical reactions under specific conditions to form new polymer networks or crosslink with existing polymer networks, thereby changing the mechanical properties of the substrate, such as increasing its elastic modulus.

[0036] Infiltration refers to the process by which a substance (such as a crosslinkable monomer or plasticizer) gradually penetrates the interior of a substrate from one surface through diffusion, capillary action, or other physical mechanisms, and moves along a specific direction (e.g., from the first surface toward the second surface). Controlling the infiltration process is crucial for the formation of gradient structures.

[0037] In-situ crosslinking: This refers to the process where crosslinkable monomers, after penetrating into the interior of a semi-cured substrate, undergo a crosslinking reaction directly within the substrate, forming a new polymer structure. This in-situ crosslinking reaction helps to transform the concentration gradient formed by penetration into a stable mechanical property gradient.

[0038] Plasticizers are small molecules that can lower the glass transition temperature of polymer materials and increase their flexibility and plasticity. When plasticizers are introduced into a substrate, they can effectively reduce the elastic modulus of the substrate, making it softer.

[0039] It should be noted that in step S20, a crosslinkable monomer is introduced into the semi-cured substrate. The crosslinkable monomer penetrates through the first surface towards the second surface and undergoes in-situ crosslinking within the semi-cured substrate, forming a high-modulus region. This high-modulus region refers to the substrate area where the elastic modulus is significantly increased after in-situ crosslinking modification with the crosslinkable monomer. This region typically possesses higher stiffness and strength, providing more stable support for flexible electronic components. In one example, the high-modulus region, where the crosslinkable monomer penetrates into the substrate, occupies one-fifth to one-half of the thickness of the semi-cured substrate.

[0040] This embodiment provides a method for preparing an encapsulation substrate. The method achieves gradient regulation of the longitudinal mechanical properties of the encapsulation substrate by precisely controlling the introduction of different modified components and in-situ reactions.

[0041] First, a semi-cured substrate is prepared. The semi-cured substrate is the foundation material for subsequent modification processes, and its structure and properties have a significant impact on the performance of the final encapsulated substrate. The semi-cured substrate is typically prepared as a thin film of a certain thickness, comprising a first surface and a second surface arranged opposite each other.

[0042] Next, crosslinkable monomers are introduced into the semi-cured substrate. The crosslinkable monomers permeate from the first surface toward the second surface. This permeation process creates a concentration gradient of crosslinkable monomers within the semi-cured substrate, with a higher monomer concentration near the first surface and a gradually decreasing concentration further away. Subsequently, the crosslinkable monomers undergo in-situ crosslinking within the semi-cured substrate, thereby forming a high-modulus substrate.

[0043] Next, a plasticizer is introduced into the semi-cured substrate after the introduction of the crosslinkable monomer. The plasticizer penetrates through the second surface toward the first surface. This step is the reverse of the direction of introducing the crosslinkable monomer, aiming to modulate the mechanical properties from the other side of the substrate. The penetration of the plasticizer also creates a concentration gradient within the substrate, with a higher concentration of plasticizer near the second surface and a lower concentration near the first surface.

[0044] Finally, the semi-cured substrate after the introduction of crosslinkable monomers and plasticizers is dried to obtain the encapsulation substrate. The purpose of the drying process is to remove any residual solvents, unreacted monomers, plasticizers, or other volatile substances from the substrate to ensure the final performance stability and purity of the encapsulation substrate.

[0045] In summary, the preparation method of this embodiment, through the preparation of a semi-cured substrate, the directional infiltration of crosslinkable monomers and plasticizers, and the in-situ crosslinking of crosslinkable monomers, successfully achieved the fabrication of an encapsulation substrate with wide-scale mechanical control and high-precision diffusion control within a vertical space of hundreds of micrometers. This technical solution provides an ideal encapsulation material for flexible bioelectronic systems, significantly improving the mechanical fit between the device and biological tissue, thereby enhancing signal fidelity and service life, and representing a significant technological advancement.

[0046] In some embodiments, step S20, introducing a crosslinkable monomer into a semi-cured substrate, wherein the crosslinkable monomer permeates through the first surface toward the second surface, and the crosslinkable monomer crosslinks in situ within the semi-cured substrate to form a high-modulus substrate, includes the following steps: S21, providing organic solvents and crosslinkable monomers; S22. Dissolve the crosslinkable monomer in an organic solvent to prepare a first permeation solution; S23. The first permeation solution is uniformly dripped onto the first surface; S24. After the addition is completed, the first surface and the first permeation solution located on the first surface are sealed, and the crosslinkable monomer can permeate through the first surface toward the second surface. S25. Then, an ultraviolet curing lamp with a preset wavelength and power is used to perform in-situ photopolymerization and crosslinking of the crosslinkable monomers that have penetrated into the semi-cured substrate to form a high-modulus substrate.

[0047] The present application describes a method that involves dissolving crosslinkable monomers in an organic solvent to prepare a first permeation solution, which is then uniformly applied to the first surface of a semi-cured substrate. The surface is subsequently sealed, effectively slowing the evaporation rate of the organic solvent and providing sufficient time for the crosslinkable monomers to penetrate uniformly and deeply into the interior of the semi-cured substrate under the influence of concentration gradient and capillary action. Once the crosslinkable monomers have fully permeated, they are irradiated with a UV curing lamp of a preset wavelength and power, initiating an in-situ photopolymerization crosslinking reaction. This crosslinking process within the substrate allows chemical bonds to form between the molecular chains of the semi-cured substrate, significantly improving the substrate's modulus and mechanical strength, ultimately forming a high-modulus substrate with the desired mechanical properties. By combining solution permeation and in-situ photopolymerization crosslinking, the method can precisely control the amount and degree of crosslinking introduced by the crosslinkable monomers, effectively avoiding problems such as uneven permeation, incomplete crosslinking, or excessively rapid surface curing that may occur in traditional methods, ensuring the uniformity of the internal structure and the stability of the performance of the high-modulus substrate.

[0048] In applications, the role of organic solvents is to dissolve crosslinkable monomers, forming a homogeneous solution, and to act as a carrier to facilitate the penetration of crosslinkable monomers into the semi-cured substrate. Organic solvents can include toluene, cyclohexane, xylene, tetrahydrofuran, etc., or acetone, ethyl acetate, chloroform, etc., the choice usually depending on the solubility of the crosslinkable monomers and their swelling effect on the semi-cured substrate. The role of the crosslinkable monomers is to carry out in-situ crosslinking reactions within the semi-cured substrate, thereby changing the mechanical properties of the substrate and forming a high-modulus substrate. Crosslinkable monomers can include methyl methacrylate, 1,6-hexanediol dimethacrylate, 1,12-dodecyl dimethacrylate, bisphenol A dimethacrylate, etc., or monomers with polymerizable double bonds such as butyl acrylate, styrene, and vinylpyrrolidone. Dissolving the crosslinkable monomers in an organic solvent to prepare a first penetration solution aims to uniformly disperse or dissolve the solid or liquid crosslinkable monomers in the organic solvent, forming a solution with a specific concentration. Preparing the solution facilitates the uniform spreading of crosslinkable monomers on the first surface of the semi-cured substrate and promotes their penetration into the substrate interior through concentration gradients and capillary forces. The preparation process can be achieved through mechanical stirring, ultrasonic dispersion, or heating dissolution. Uniformly dropping the first permeation solution onto the first surface is the initial step for the crosslinkable monomers to enter the semi-cured substrate. Uniform dropping ensures the initial consistent distribution of crosslinkable monomers on the first surface of the semi-cured substrate, laying the foundation for subsequent uniform penetration. Various methods can be used for dropping, such as pipettes, spray devices, doctor blades, or dip coating. After dropping, the first surface and the first permeation solution on it are sealed. This seal prevents the organic solvent from evaporating too quickly, maintaining the presence of the first permeation solution on the first surface of the semi-cured substrate, thus providing sufficient penetration time for the crosslinkable monomers. Simultaneously, the sealing process also helps establish and maintain the concentration gradient required for penetration within the semi-cured substrate, promoting deeper penetration of the crosslinkable monomers from the first surface to the second surface. Sealing can be achieved by covering the substrate with an inert film (such as polyester or polyethylene film), placing the semi-cured substrate in a sealed container, or performing the process in a controlled humidity environment. Subsequently, an ultraviolet (UV) curing lamp with a preset wavelength and power is used to perform in-situ photopolymerization crosslinking of the crosslinkable monomers that have penetrated the semi-cured substrate, forming a high-modulus substrate. The role of the UV curing lamp is to provide UV light energy of a specific wavelength, initiating the photopolymerization reaction of the crosslinkable monomers that have penetrated into the semi-cured substrate, forming a crosslinked network. The selection of the preset wavelength and power is crucial; it needs to match the absorption spectrum of the photoinitiator of the crosslinkable monomers and be precisely controlled according to the required crosslinking depth and degree. In-situ photopolymerization crosslinking ensures that the crosslinking reaction occurs within the semi-cured substrate, thereby effectively improving the modulus and mechanical strength of the substrate without damaging its overall structure. Various light sources can be used for UV curing, such as high-pressure mercury lamps, LED UV lamps, and xenon lamps.

[0049] In some embodiments, the concentration of the first permeation solution is 200–6000 mg / mL. The concentration of the first permeation solution refers to the content of crosslinkable monomers in the organic solvent. The concentration directly affects the rate and depth of monomer permeation, as well as the uniformity of monomer distribution within the semi-cured substrate. Too low a concentration may result in low permeation efficiency, making it difficult to form a sufficiently high-modulus region; too high a concentration may cause premature crosslinking of monomers on the surface, hindering deep permeation, or causing excessive swelling of the semi-cured substrate.

[0050] The present application's solution, by selecting specific crosslinkable monomers (such as methyl methacrylate) and organic solvents (such as toluene), and controlling the concentration of the first permeation solution within the range of 200~6000 mg / mL, can precisely control the permeation behavior of crosslinkable monomers in a semi-cured substrate. Specifically, a suitable combination of monomers and solvents ensures that the monomers have good solubility and diffusivity within the semi-cured substrate, avoiding premature curing or uneven permeation on the surface. Simultaneously, controlling the solution concentration within a specific range ensures sufficient monomer quantity to form a high-modulus region while avoiding substrate swelling or impaired permeation due to excessive concentration. When the first permeation solution is uniformly dripped onto the first surface and sealed, the selected organic solvent effectively carries the crosslinkable monomers, allowing them to permeate from the first surface to the second surface in a controlled manner through capillary action or diffusion.

[0051] In some embodiments, step S30, introducing a plasticizer into the semi-cured substrate after introducing the crosslinkable monomer, and the step of the plasticizer penetrating through the second surface toward the first surface includes: S31. Provide organic solvents and plasticizers; S32. Dissolve the plasticizer in an organic solvent to prepare a second permeation solution; S33. The second permeation solution is uniformly dripped onto the second surface; S34. After the addition is completed, the second surface and the second permeation solution located on the second surface are sealed to allow the plasticizer to permeate through the second surface toward the side of the first surface.

[0052] This application enables precise control of the plasticizer infiltration process. By dissolving the plasticizer in an organic solvent to form a permeation solution and adding it uniformly dropwise, a highly consistent initial distribution of the plasticizer on the substrate surface can be ensured, thus avoiding substrate performance differences caused by uneven infiltration. Furthermore, the sealing treatment after dropwise addition effectively slows down the evaporation rate of the organic solvent, providing sufficient infiltration time for the plasticizer to penetrate deeper and more uniformly into the interior of the high-modulus substrate, thereby achieving precise control over the flexibility and modulus of the encapsulated substrate. This controlled infiltration method not only improves the utilization rate of the plasticizer and reduces material loss but also helps reduce the environmental impact of organic solvents, ultimately producing a stable and uniform encapsulated substrate.

[0053] In applications, organic solvents serve as carriers for plasticizers, primarily dissolving them and facilitating their penetration into high-modulus substrates. The choice of organic solvent is typically based on its ability to dissolve plasticizers, its volatility, and its compatibility with high-modulus substrates. Besides toluene, cyclohexane, xylene, and tetrahydrofuran, acetone, chloroform, dichloromethane, and ethyl acetate can also be used. Plasticizers are additives that increase the flexibility of materials and lower their glass transition temperature and modulus. They improve the plasticity of materials by reducing the intermolecular forces between polymer chains. Besides polyisobutylene oligomers, silanized polybutene, squalene, and white oil, plasticizers can also be phthalate compounds, such as dibutyl phthalate and dioctyl phthalate, or citrate compounds, such as tributyl citrate, as well as epoxidized soybean oil and polyethylene glycol. The aforementioned plasticizers are additives that can increase the flexibility of materials and lower the glass transition temperature. They improve the ductility and processing performance of materials by reducing the interaction forces between polymer molecular chains.

[0054] In step S32, the plasticizer is dissolved in an organic solvent to prepare a second permeation solution. This step aims to introduce the plasticizer in solution form to facilitate its uniform dispersion and permeation. Dissolving the plasticizer in an organic solvent reduces its viscosity, making it easier to diffuse through the pores or molecular chain gaps of the high-modulus substrate.

[0055] In step S33, the second permeation solution is uniformly dripped onto the second surface. This step is crucial to ensuring that the plasticizer is uniformly distributed on the surface of the semi-cured substrate after the introduction of crosslinkable monomers before permeation. Uniform dripping avoids the formation of a concentration gradient of plasticizer within the substrate, thereby ensuring the uniformity of the final encapsulated substrate's performance. There are various ways to achieve uniform dripping. For example, a precision drip pump can be used for point-to-point or line-to-line dripping, or techniques such as spraying, dip coating, blade coating, or roller coating can be used to uniformly coat the second permeation solution onto the second surface.

[0056] In step S34, after the dripping is completed, the second surface and the second permeation solution located on the second surface are sealed to allow the plasticizer to permeate through the second surface towards the first surface. The purpose of the sealing treatment is to control the evaporation rate of the organic solvent and prolong the residence time of the plasticizer on the surface of the semi-cured substrate after the introduction of the crosslinkable monomer, thereby providing sufficient permeation time for the plasticizer to ensure it can fully and deeply penetrate into the substrate. Simultaneously, the sealing treatment also helps reduce the release of organic solvents into the environment, minimizing the impact on operators and the environment.

[0057] It should be noted that by synergistically controlling the initial degree of curing of the semi-cured substrate (the complex shear viscosity varies from 0.1 to 20 kPa·s, with higher viscosity indicating higher degree of curing) and the dynamic dosing of the permeation solution (50 μL to 2 mL), precise control of the diffusion depth of plasticizers and crosslinkable monomers in the thickness direction of the substrate can be achieved (the minimum horizontal diffusion distance can be controlled at 50 μm, and the vertical diffusion distance is 50 to 500 μm), thereby establishing the spatial boundary of the mechanical gradient.

[0058] This application's solution provides an organic solvent and a plasticizer, dissolving the plasticizer in the organic solvent to prepare a second permeation solution. This solution is then uniformly dripped onto the second surface of a semi-cured substrate. After dripping, the second surface and the solution are sealed, thereby achieving controlled permeation of the plasticizer from the second surface towards the first surface. Specifically, the organic solvent acts as a carrier, introducing the plasticizer in the form of a low-viscosity solution, facilitating its diffusion within the substrate. Uniform dripping ensures the initial uniformity of the plasticizer's distribution on the substrate surface, laying the foundation for subsequent uniform permeation. The sealing treatment effectively suppresses the rapid evaporation of the organic solvent, prolonging the contact time between the plasticizer and the substrate. This allows the plasticizer sufficient time and driving force to gradually permeate from the second surface to the first surface through mechanisms such as diffusion and capillary action. This controlled permeation process enables the plasticizer to uniformly and deeply penetrate the semi-cured substrate, effectively regulating the substrate's mechanical properties to achieve the desired flexibility and modulus.

[0059] In some embodiments, the concentration of the second permeation solution is 200–6000 mg / mL. Controlling the concentration of the second permeation solution within the range of 200–6000 mg / mL ensures that the plasticizer has suitable solubility and permeation driving force in the solution. After the second permeation solution is uniformly dropped onto the second surface and sealed, the plasticizer molecules can permeate at a controlled rate through the second surface toward the side of the first surface. This precise selection and concentration control of the plasticizer allows it to penetrate uniformly and deeply into the interior of the substrate, avoiding problems such as uneven permeation, low efficiency, or substandard material properties caused by improper plasticizer selection or concentration imbalance.

[0060] In some embodiments of this application described above, step S10, preparing the semi-cured substrate, includes: S11, providing polymers and organic solvents; S12. Dissolve the polymer in an organic solvent and stir under preset conditions to obtain a transparent and clear polymer solution; S13. Place the polymer solution in a closed environment at a preset temperature. After the solvent evaporates, a semi-cured substrate is obtained.

[0061] The above-described technical solution employs solution casting to prepare semi-cured substrates, enabling precise control over their microstructure and macroscopic uniformity. By fully dissolving the polymer in an organic solvent and controlling the slow evaporation of the solvent, defects such as uneven porosity, unstable density, or surface roughness during the molding process can be effectively avoided. This uniform and controllable semi-cured substrate structure provides an ideal channel for the uniform penetration of crosslinkable monomers and plasticizers, ensuring the uniformity of in-situ crosslinking of crosslinkable monomers within the semi-cured substrate to form a high-modulus substrate, as well as the uniform distribution of plasticizers during subsequent penetration. Ultimately, this contributes to obtaining encapsulation substrates with stable performance, excellent mechanical properties, and low defect rates, significantly improving the overall quality and reliability of the encapsulation substrate.

[0062] In other embodiments, step S10, the step of preparing the semi-cured substrate, includes: S100, provides polymers and crosslinking agents; S101. The polymer and the crosslinking agent are mixed evenly at a preset temperature and a preset shear rate to obtain a blend. S102. The blend is pressed into a tablet to obtain a semi-cured substrate; or, the polymer is blended with a crosslinking agent, or the polymer, crosslinking agent and initiator are blended in solution, and after film formation, a semi-cured substrate is obtained by controlling the UV exposure dose (time / intensity) or controlling the heat treatment step time.

[0063] Through the above technical solutions, this application provides a controllable and efficient method for preparing a semi-cured substrate. Whether through mechanical mixing and pressing or through solution blending and film formation with controlled crosslinking, the prepared semi-cured substrate can be ensured to have a uniform component distribution and stable physical structure. This uniformity and stability are crucial for the subsequent penetration of crosslinkable monomers and plasticizers, ensuring a consistent penetration path for these active substances within the semi-cured substrate and avoiding problems such as uneven local penetration or insufficient penetration depth. Furthermore, by precisely controlling the degree of crosslinking, the semi-cured substrate can maintain sufficient mechanical strength while possessing an appropriate pore structure or molecular chain spacing, thereby optimizing the adsorption and transport capabilities for crosslinkable monomers and plasticizers. Ultimately, this carefully prepared semi-cured substrate can significantly improve the overall performance of the encapsulation substrate, including its mechanical strength, dimensional stability, and adhesion to subsequent encapsulation materials, thus effectively solving the technical problem of insufficient uniformity and controllability in the preparation of semi-cured substrates.

[0064] In applications, polymers are blended with crosslinking agents, or polymers, crosslinking agents, and initiators are blended in solution. After film formation, the semi-cured substrate is obtained by controlling the UV exposure dose (time / intensity) or the heat treatment step time. This is an alternative method for preparing semi-cured substrates, especially suitable for scenarios requiring thin-film substrates or higher uniformity requirements. Blending in solution allows for finer molecular-level dispersion. The initiator's role here is to initiate the crosslinking reaction; for example, photoinitiators generate active free radicals under UV irradiation, and thermal initiators decompose to generate active free radicals under heating conditions. After film formation, the degree of crosslinking reaction can be controlled by precisely controlling the UV exposure dose (i.e., exposure time and light intensity) or the temperature and time step of heat treatment, thereby obtaining a substrate with a specific crosslinking density and semi-cured state. In addition to UV curing, electron beam curing or gamma ray curing can also be used.

[0065] This application addresses the challenges of uniformity and controllability in the preparation of semi-cured substrates by providing polymers and crosslinking agents as base materials and employing two main approaches. The first approach involves thoroughly mixing the polymer and crosslinking agent at a preset temperature and shear rate to form a homogeneous blend. This blend is then molded into a semi-cured substrate with a specific shape and thickness through compression molding. This method ensures uniform distribution of material components and macroscopic dimensional stability of the substrate through mechanical mixing and physical molding. The second approach is more refined, allowing the blending of polymers, crosslinking agents, and even initiators in solution, achieving superior molecular-level dispersion. Subsequently, a film is obtained through a film-forming process, and the degree of crosslinking reaction is induced and controlled by precisely controlling the UV exposure dose or heat treatment step time, ultimately yielding the semi-cured substrate. Both methods aim to introduce appropriate crosslinking into the polymer matrix to achieve a "semi-cured" state—possessing sufficient structural integrity and mechanical strength to support subsequent processing while retaining a certain degree of permeability and reactivity, allowing crosslinkable monomers and plasticizers to effectively penetrate and react in situ.

[0066] In some embodiments, the polymer includes at least one selected from styrene-butadiene-styrene block copolymer, styrene-isobutylene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, polyurethane, and polyisobutylene. Styrene-butadiene-styrene block copolymer (SBS) is a typical thermoplastic elastomer that combines the elasticity of rubber with the processability of plastics. Its hard segments (styrene) provide strength, and its soft segments (butadiene) provide elasticity, resulting in semi-cured substrates prepared from it exhibiting good flexibility and mechanical strength. Styrene-isobutylene-styrene block copolymer (SIBS) is another thermoplastic elastomer whose isobutylene soft segments impart excellent gas barrier properties, chemical stability, and biocompatibility to the material. This makes semi-cured substrates prepared from SIBS potentially advantageous in applications requiring high barrier properties or biomedical applications. Hydrogenated styrene-butadiene-styrene block copolymer (SEBS) is a hydrogenated product of SBS. Through hydrogenation, the double bonds in the butadiene segments are saturated, thereby significantly improving the material's weather resistance, UV aging resistance, and thermal stability. Therefore, semi-cured substrates prepared using SEBS exhibit longer service life and more stable performance under harsh environments. Polyurethane (PU) is a class of versatile polymer materials, capable of achieving a wide range of properties from elastomers to rigid plastics by adjusting the ratio of soft to hard segments and crosslinking density. Polyurethane possesses excellent abrasion resistance, oil resistance, high strength, and good adhesion properties, providing customized mechanical properties and good interfacial bonding for semi-cured substrates. Polyisobutylene (PIB) is a saturated amorphous polymer renowned for its extremely low gas permeability, excellent chemical resistance, and good flexibility. Semi-cured substrates prepared from PIB perform exceptionally well in applications requiring excellent sealing and chemical inertness.

[0067] This application prepares a semi-cured substrate by selecting at least one of specific polymers, namely styrene-butadiene-styrene block copolymers, styrene-isobutylene-styrene block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, polyurethane, and polyisobutylene. These polymers have unique molecular structures and physicochemical properties, which ensure that the prepared semi-cured substrate is structurally stable and has an appropriate pore structure or permeation channels.

[0068] In some embodiments, before introducing a crosslinkable monomer into the semi-cured substrate after obtaining the semi-cured substrate, the method includes: Place the physical mask on the first and second surfaces of the semi-cured substrate, and align the three precisely. Subsequently, the above components are placed under a vacuum press to apply pressure, ensuring that the mask plate and the semi-cured substrate are tightly bonded without gaps.

[0069] By adopting the above steps, the patterning process of the packaging substrate is achieved.

[0070] A physical mask is a thin, patterned structure with specific openings used for selective surface treatment of materials. Its function is to pattern the surface of a substrate and precisely define the penetration area of ​​a penetrant (such as a crosslinkable monomer or plasticizer), preventing it from diffusing into unwanted areas, thus achieving area-selective penetration. Physical masks can be made of various materials, such as metal sheets, polymer films, or ceramics, and their patterns can be formed through laser cutting, chemical etching, or precision stamping. Placing the physical mask on two opposing surfaces of a prepreg substrate allows for area-selective penetration of these two surfaces in subsequent penetration steps. Precise alignment refers to the precise positional matching of the prepreg substrate with the physical mask placed on its first and second surfaces. This is crucial for ensuring the accuracy of the penetration area and the performance of the subsequent encapsulated substrate. Precise alignment can be achieved through optical alignment systems, mechanical locating pins, or guide grooves to ensure that the mask pattern precisely coincides with the target area on the substrate. A vacuum press is a device that applies uniform pressure to an object in a vacuum environment. In this step, the assembly consisting of the semi-cured substrate and the mask is placed under pressure in a vacuum press to eliminate any air gaps between the mask and the substrate, ensuring a tight bond. The applied pressure can be constant or stepped to accommodate the properties of different materials. A tight, gapless bond is crucial for achieving precise area penetration. By applying pressure under a vacuum press, the mask is effectively compacted onto the surface of the semi-cured substrate, eliminating tiny gaps between them. This prevents the penetrant from leaking out from the edges or gaps of the mask during penetration, ensuring clear boundaries and accurate shape of the penetration area. Besides a vacuum press, hot pressing, rolling, or the use of self-adhesive masks can also aid in achieving a tight bond.

[0071] In one specific embodiment, a physical mask is placed on the upper and lower surfaces of the obtained semi-cured encapsulation substrate film, and the three are precisely aligned. Subsequently, the above components are placed under a vacuum press to apply pressure, ensuring that the mask plate and the substrate film are tightly bonded without gaps.

[0072] Next, a certain amount of crosslinkable monomer / toluene solution is drop-coated onto the patterned cutout area of ​​the photomask and sealed to ensure full vertical penetration of the solution into the film. After standing until no solvent residue remains on the surface, the film is transferred to a glove box and subjected to ultraviolet light irradiation to initiate a crosslinking reaction. Then, the film is flipped over, and a certain amount of plasticized small molecule / toluene solution is drop-coated onto the corresponding patterned cutout area on the other side. It is then sealed again and allowed to stand for penetration. After a predetermined standing time, the sealed cap is opened to allow the solvent to evaporate completely. Finally, the physical photomasks on both the upper and lower surfaces are removed to obtain a substrate film with a patterned mechanical property selective design.

[0073] In the above specific embodiments, the selected solvents are volatile nonpolar or weakly polar solvents, including toluene, cyclohexane, xylene, and tetrahydrofuran. These solvents have low kinematic viscosity, moderate surface tension, and low boiling points. Preferably, weakly polar aromatic solvents such as toluene and xylene are used because they can form an excellent swelling effect with the substrate material (especially block copolymers containing benzene rings), fully opening up the free volume between polymer chain segments.

[0074] It should be noted that, in addition to using physical mask technology to achieve surface patterning design of the packaging substrate, photolithography masks, chemical masks, etc., can also be used to prepare substrates with patterned mechanical property distributions. Besides physical masks, the patterned region design described in this invention can also be achieved using laser direct writing technology and inkjet printing technology. Furthermore, selective wetting and penetration of solutions can be achieved by pre-applying hydrophobic / hydrophilic patterns on the substrate surface and utilizing surface tension differences.

[0075] Secondly, this application proposes an encapsulation substrate, which is prepared using the above-described method.

[0076] The encapsulation substrate achieves a gradient distribution of mechanical properties in the longitudinal direction through the above-described preparation method. Specifically, its structural feature is that it includes a high-modulus region and a low-modulus region distributed sequentially from the first surface to the second surface. The high-modulus region is formed by in-situ crosslinking of crosslinkable monomers, while the low-modulus region is formed by plasticizer infiltration modification. The two regions form a continuous transitional mechanical gradient interface in the vertical direction. The core innovation of this embodiment lies in combining the unidirectional infiltration and in-situ crosslinking of crosslinkable monomers with the reverse infiltration of plasticizers in a sequential superposition manner. This achieves simultaneous wide-scale mechanical regulation and high-precision diffusion control within a vertical space of hundreds of micrometers, effectively solving the problem of blurred mechanical gradient boundaries caused by solution boundary diffusion in existing technologies. This achieves the effect of avoiding interlayer delamination and strengthening the mechanical matching of the substrate / biological tissue interface.

[0077] To address the limitations of existing horizontal control methods in meeting the requirements of longitudinal dynamic service, the solution proposed in this application constructs an encapsulation substrate through the aforementioned preparation method. Its longitudinal mechanical gradient structure can precisely adapt to the asymmetric mechanical properties of hard electronic components and soft biological tissues.

[0078] Example Example 1 This application provides a packaging substrate and a method for preparing the same, wherein the preparation method includes the following steps: S10. Prepare a semi-cured substrate, the semi-cured substrate including a first surface and a second surface disposed opposite to each other; At room temperature, 4 g of SIBS was added to 20 mL of toluene solvent and stirred until completely dissolved, yielding a SIBS solution with a concentration of 200 mg / mL. The SIBS solution was poured into a self-made glass mold (3 cm × 3 cm) and allowed to stand at room temperature for 4 hours to allow partial evaporation of the solvent, forming a semi-cured SIBS substrate with certain mechanical strength and containing residual solvent. Its viscosity was measured to be 4 kPa·s using a shear rheometer.

[0079] S20. Introduce crosslinkable monomers into the semi-cured substrate. The crosslinkable monomers permeate through the first surface towards the second surface and crosslink in situ within the semi-cured substrate to form a high-modulus substrate. Precisely attach physical masks with specific geometric patterns to the upper and lower surfaces of the semi-cured SIBS substrate. Place the above components in a vacuum press and hot-press at 40ºC and 0.2MPa for 3 minutes to completely eliminate the micro-gaps between the mask and the substrate.

[0080] 2 g of hexanediol dimethacrylate monomer, 0.02 g of 2,2-diethoxyacetophenone, and 0.02 g of pentaerythritol-3-mercaptopropionate were dissolved in 1 mL of toluene to prepare a crosslinking solution with a concentration of 2 g / mL. 0.8 mL of the crosslinking solution was evenly spread onto the upper surface of the semi-cured SIBS substrate (from the cutout area of ​​the photomask) using a high-precision peristaltic pump. The substrate was then sealed with a glass cover and allowed to stand for 2 hours to allow the crosslinkable monomers to penetrate vertically into the substrate.

[0081] The glass cover was then removed, and the solvent on the upper surface was allowed to evaporate completely. The film was then transferred into a nitrogen-protected glove box and irradiated with a UV curing lamp (wavelength 365nm, power 100mW / cm²) for 10 minutes to allow the hexanediol dimethacrylate monomers that had penetrated into the substrate to undergo in-situ crosslinking, forming a high-modulus region.

[0082] S30. A plasticizer is introduced into the semi-cured substrate after the introduction of the crosslinkable monomer, and the plasticizer penetrates through the second surface toward the first surface. 2g of PIB with a molecular weight of 400g / mol was dissolved in 1mL of toluene to prepare a plasticizing solution of 2g / mL. The substrate obtained in the above steps was then flipped over, and 1mL of plasticizing solution was evenly spread on the lower surface (from the cutout area of ​​the mask). The substrate was then sealed with a glass cover and left to stand for 2 hours to induce the diffusion of PIB molecules into the interior of the substrate.

[0083] S40. The semi-cured substrate after the introduction of crosslinkable monomers and plasticizers is dried to obtain the encapsulation substrate.

[0084] Example 2 This embodiment is basically the same as Example 1, except that SEBS is used as the base material, and 4g of methyl methacrylate monomer is dissolved in 1mL of xylene to prepare a crosslinking solution with a concentration of 4g / mL.

[0085] Comparative Example Comparative Example 1 The main difference from Example 1 is that a crosslinking solution was used for modification before the SIBS solution cured. Because the SIBS is in solution, the diffusion of the hexanediol dimethacrylate monomer is unrestricted, allowing it to penetrate instantly to the bottom, resulting in a SIBS substrate with more uniform mechanical properties after modification with hexanediol dimethacrylate, whose modulus is higher than that of the pure SIBS substrate.

[0086] Comparative Example 2 The main difference from Example 1 is that a plasticizing solution was used for modification before the SIBS solution solidified. Since SIBS is in a solution state, PIB diffusion is unrestricted and can instantly penetrate to the bottom, resulting in a PIB-modified SIBS substrate with more uniform mechanical properties and a lower modulus than the pure SIBS substrate.

[0087] Performance testing and test results 1. During the thin film preparation process, the fluorescent dyes coumarin 6 and Nile Red were added to the permeation solution PIB / toluene and the ethylene glycol dimethacrylate monomer / toluene solution, respectively, and the structure was characterized by laser confocal microscopy. Figure 2 As shown in the left figure, the green area represents the softening area after permeation with the PIB / toluene solution, the red area represents the hardening area after permeation with the methacrylate monomer / toluene solution, and the black area in the middle represents SIBS.

[0088] The cross-sections of the obtained encapsulation substrate films were tested using nanoindentation. The results showed that, under the same displacement, the region with the largest force was the methacrylate-infiltrated region, followed by SIBS, while the region with the smallest force response was the PIB-infiltrated region. The fitted moduli were 1 GPa, 30 MPa, and 5 MPa, respectively. These results indicate that encapsulation films with mechanical gradient designs can be obtained through selective infiltration.

[0089] The elastic modulus of the encapsulation substrates obtained in the above embodiments and comparative examples was tested. The specific testing method included testing the cross-section of the sample using dynamic nanoindentation. Two regions near the surface and the middle region were selected for testing. The amplitude displacement was controlled at 2 nm, the test frequency was 100 Hz, and the maximum applied force was 100 μN.

[0090] The test data is shown in the table below:

[0091] It should be noted that, in the table, the upper layer refers to the side of the encapsulation substrate closest to the first surface, the lower layer refers to the side of the encapsulation substrate closest to the second surface, and the middle layer refers to the portion between the upper and lower layers. This description is used to clearly demonstrate the tiered design of the energy storage modulus of the encapsulation substrate, thereby reflecting the preparation method provided in this application. By permeating crosslinkable monomers and plasticizer molecules onto both sides of the semi-cured substrate, an encapsulation substrate with a mechanical gradient design can be obtained.

[0092] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0093] The above-described embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them. Although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of the embodiments of this application.

Claims

1. A method for preparing an encapsulation substrate, characterized in that, Includes the following steps: A semi-cured substrate is prepared, the semi-cured substrate comprising a first surface and a second surface disposed opposite to each other; A crosslinkable monomer is introduced into the semi-cured substrate. The crosslinkable monomer penetrates through the first surface toward the second surface and crosslinks in situ within the semi-cured substrate. The penetration process causes the crosslinkable monomer to form a concentration gradient within the semi-cured substrate, i.e., the concentration of the crosslinkable monomer in the region near the first surface is higher than the concentration of the crosslinkable monomer in the region away from the first surface. A plasticizer is introduced into a semi-cured substrate after the introduction of a crosslinkable monomer. The plasticizer penetrates through the second surface toward the first surface. The penetration process causes the plasticizer to form a concentration gradient inside the semi-cured substrate, that is, the concentration of the plasticizer in the region near the second surface is higher than the concentration of the plasticizer in the region near the first surface. The semi-cured substrate after the introduction of the crosslinkable monomer and the plasticizer is dried to obtain the encapsulation substrate; The crosslinkable monomer includes at least one of methyl methacrylate, 1,6-hexanediol dimethacrylate, 1,12-dodecyl dimethacrylate, and bisphenol A dimethacrylate.

2. The preparation method according to claim 1, characterized in that, The step of introducing a crosslinkable monomer into the semi-cured substrate, wherein the crosslinkable monomer permeates through the first surface toward the second surface, and the crosslinkable monomer crosslinks in situ within the semi-cured substrate, includes: Provide organic solvents and crosslinkable monomers; The crosslinkable monomer is dissolved in the organic solvent to prepare a first permeation solution; The first permeation solution is evenly dripped onto the first surface; The first surface and the first permeation solution located on the first surface are sealed, and the crosslinkable monomer permeates through the first surface toward the second surface. In-situ photopolymerization and crosslinking of crosslinkable monomers that have penetrated into the semi-cured substrate are performed using a UV curing lamp with a preset wavelength and power.

3. The preparation method according to claim 2, characterized in that, The organic solvent includes at least one selected from toluene, cyclohexane, xylene, and tetrahydrofuran; and / or, The concentration of the first permeation solution is 200~6000 mg / mL.

4. The preparation method according to claim 1, characterized in that, Introducing a plasticizer into a semi-cured substrate after the introduction of a crosslinkable monomer, the plasticizer penetrating through the second surface toward the first surface, comprising: Provide organic solvents and plasticizers; The plasticizer is dissolved in the organic solvent to prepare a second permeation solution; The second permeation solution is evenly dripped onto the second surface; The second surface and the second permeation solution located on the second surface are sealed to allow the plasticizer to permeate through the second surface toward one side of the first surface.

5. The preparation method according to claim 4, characterized in that, The plasticizer includes at least one of polyisobutylene oligomer, silanized polybutene, squalane, and white oil; and / or The concentration of the second permeation solution is 200~6000 mg / mL.

6. The preparation method according to claim 1, characterized in that, The preparation of the semi-cured substrate includes: Provides polymers and organic solvents; The polymer is dissolved in the organic solvent and stirred under preset conditions to obtain a transparent and clear polymer solution; The polymer solution is placed in a closed environment at a preset temperature, and the semi-cured substrate is obtained after the solvent evaporates.

7. The preparation method according to claim 1, characterized in that, The preparation of the semi-cured substrate includes: Provide polymers and crosslinking agents; The polymer and the crosslinking agent are mixed uniformly at a preset temperature and a preset shear rate to obtain a blend. The blend is compressed into tablets to obtain the semi-cured substrate; or, The polymer is blended with a crosslinking agent, or the polymer, crosslinking agent and initiator are blended in solution. After film formation, the semi-cured substrate is obtained by controlling the UV exposure dose (time / intensity) or the heat treatment step time.

8. The preparation method according to claim 6 or 7, characterized in that, The polymer includes at least one of styrene-butadiene-styrene block copolymer, styrene-isobutylene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, polyurethane, and polyisobutylene.

9. The preparation method according to claim 1, characterized in that, Before introducing the crosslinkable monomer into the semi-cured substrate after obtaining it, the process includes: The physical mask is placed on the first and second surfaces of the semi-cured substrate, and the three are precisely aligned. Subsequently, the physical mask and the semi-cured substrate are placed under a vacuum press to apply pressure, ensuring that the mask and the semi-cured substrate are tightly bonded and without gaps.

10. A packaging substrate, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 9.

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