Silica, method for producing the same, resin composition, and use thereof

Abstract

The application provides a kind of silicon dioxide and its preparation method, resin composition and its application, it is related to the field of semiconductor packaging material.The silicon dioxide described in the application includes first particle and second particle, the number of first particle is controlled in the range of ≤50%, the maximum width of the concave surface in the first particle is in the range of 3%-85% of the particle diameter, which can make the copper-clad plate prepared have excellent low dielectric performance and high peel strength, so that the copper-clad plate has processability.When the first particle with recessed area in the silicon dioxide is combined with the resin, a structure similar to mortise and tenon can be formed, the silicon dioxide can form a firm chemical bond and mechanical interlocking structure with the resin through the chemical bond of the modifier, increase the peel strength of the copper-clad plate, and thus make the copper-clad plate have processability.The existence of internal pores of the silicon dioxide makes it meet the low dielectric constant and low dielectric loss performance required by high-frequency high-speed copper-clad plate.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging materials, and in particular to a silicon dioxide and its preparation method, a resin composition and its application. Background Technology

[0002] High-frequency and high-speed copper-clad laminates (CCLs) are a special type of copper-clad laminate material designed specifically for high-frequency and high-speed signal transmission. They maintain signal integrity and stability in high-frequency bands (such as 5G communication bands) and high-speed data transmission environments. With a low dielectric constant, high-frequency and high-speed CCLs effectively reduce signal transmission delay and distortion, thereby increasing signal transmission speed.

[0003] Hollow spherical silica, due to its hollow structure with air inside and amorphous silica outside, has overall electrical properties that are intermediate between those of air and amorphous silica, exhibiting low dielectric properties. In the industry, hollow spherical silica is often used as a substitute for solid spherical silica as a high-performance filler in the fabrication of high-frequency, high-speed copper-clad laminates.

[0004] However, hollow spherical silica has the following disadvantages due to its significant stress concentration effect: 1. Local fragility problem: The outer shell is very thin, and any local impact, dent or manufacturing defect will cause huge stress concentration, which can easily lead to brittle fracture or plastic instability (being crushed).

[0005] 2. Buckling problem: Under compressive load, thin-walled hollow spheres are prone to buckling, that is, the structure suddenly loses stability and collapses, resulting in low peel strength of copper clad laminate material, making it difficult to use in the harsh copper clad laminate manufacturing process. Summary of the Invention

[0006] The purpose of this application is to provide a silicon dioxide and its preparation method, a resin composition and its application, which meet the requirements of low dielectric properties, while improving peel strength and making the copper clad laminate processable.

[0007] For the purposes mentioned above, this application provides the following technical solution: In a first aspect, this application provides a silicon dioxide comprising a first particle having at least one recessed region on its surface and a second particle not having a recessed region on its surface, wherein the first particle has a diameter; The recessed area extends inward along the surface of the first particle, and each recessed area forms a recessed surface on the surface of the first particle. The recessed surface has a maximum width, and the maximum width is not greater than 85% of the diameter. The first particle accounts for 10-50% of the total number of particles. The maximum width of the concave surface is the maximum width of the largest concave surface in the first particle.

[0008] Furthermore, in some embodiments of this application, at least a portion of the recessed area has a protrusion that protrudes outwardly along the surface of the first particle in the circumferential direction of the recessed surface formed on the surface of the first particle.

[0009] Furthermore, in some embodiments of this application, the protrusion forms an angle with the recessed surface, and the angle is an acute angle, a right angle, or an obtuse angle.

[0010] Furthermore, in some embodiments of this application, the first particle and / or the silicon dioxide is spherical or near-spherical.

[0011] Furthermore, in some embodiments of this application, the maximum width of the recessed surface of the first particle is not higher than 50% of the particle diameter; and / or, The first particle accounts for 1%-50% of the total number of particles, preferably 10%-50%.

[0012] Furthermore, in some embodiments of this application, the silicon dioxide has pores inside, the diameter of the pores is 0.7%-20% of the diameter of the first or second particle, and the spacing between adjacent pores is greater than 0 and less than or equal to 500 nm.

[0013] Furthermore, in some embodiments of this application, the silicon dioxide satisfies one or more of the following conditions: (1) The purity of the silicon dioxide is ≥99%; (2) The content of magnetic impurities in the silica is ≤5ppm; (3) The hollowness of the silica is 0.6-2.0; (4) The silica particle size is 0.2-20 μm; (5) The BET of the silicon dioxide is ≤60m² / g; (6) The conductivity of the silicon dioxide is ≤20μS / cm.

[0014] Secondly, this application also provides a method for preparing silicon dioxide, comprising the following steps: (1) Preparation of prepolymer: Silica prepolymer is prepared by vacuum distillation using raw materials containing silicon source; (2) Preparation of silicon dioxide: The silicon dioxide was obtained by calcination; The process includes a step of mixing the silica prepolymer with water before calcination.

[0015] Furthermore, in some embodiments of this application, step (1) further includes an acid treatment step before vacuum distillation, wherein the pH of the solution is controlled to be 4-5 after adding acid; and / or, In step (2), water is added and mixed at a mass ratio of silica prepolymer to water of 1:(5-30); and / or The step (2) after water treatment also includes an alkali treatment step to control the pH of the reaction solution to 10-11.

[0016] Furthermore, in some embodiments of this application, the calcination conditions of step (2) are as follows: heating to 800-1000℃ at a heating rate of 0.5-1℃ / min and holding for 60-180min; then heating to 900-1100℃ at a heating rate of 0.5-1℃ / min and holding for 120-240min.

[0017] Furthermore, in some embodiments of this application, the raw materials in step (1) include: a silicon source, a surfactant, ethanol, and water, in a mass ratio of (80-100):(1-10):5:5; and / or, The alkali mentioned in step (2) is ammonia.

[0018] Furthermore, in some embodiments of this application, the preparation method further includes a modification step of modifying the silica using a modifier, wherein the modifier is Y(CH2)3Si(OR)3, wherein Y is selected from at least one of amino, epoxy, vinyl, phenyl, and perfluoroalkyl groups, and R is selected from at least one of methyl and ethyl groups, and / or, The mass of the modifier is 0.5%-2% of the mass of the porous silica.

[0019] Thirdly, this application also provides a resin composition, which is obtained by reacting the silica with a resin and a curing agent, and / or The viscosity of the resin composition is 500-2000 mPa·s.

[0020] Furthermore, in some embodiments of this application, the mass ratio of the silica, the resin, and the curing agent is 40:60:12, and / or, The resin is at least one of epoxy resin, bismaleimide, cyanate ester, polytetrafluoroethylene, polyphenylene ether, and benzoxazine, and the curing agent is an anhydride type curing agent.

[0021] Specifically, the anhydride-type curing agent is selected from at least one of phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, and methylcyclohexane tetracarboxylic anhydride.

[0022] Fourthly, this application also provides an application of a silicon dioxide or resin composition, the application including electronic components or functional materials, wherein the electronic components are one of semiconductor devices, copper-clad laminates, integrated circuits, electronic chips, radio frequency devices, flexible display devices, antenna devices, flexible wiring devices, and sensor devices, and the functional materials are one of advanced packaging materials, thermal insulation materials, and lightweight materials.

[0023] The superior effects of this application include: The silica provided in this application comprises a first particle with a surface depression and a second particle without a surface depression. In application, the depression in the first particle can bond with resin to form a mortise-and-tenon structure, thereby enhancing the peel strength of the copper-clad laminate. Furthermore, the protrusions of the first particle further increase the contact area with the resin, further enhancing peel strength. Simultaneously, when the number of the first particle accounts for ≤50% of the total silica particles, and the maximum width of the depression surface in the depression area is 3%-85% of the diameter of the first particle, the copper-clad laminate can be guaranteed to have both high peel strength and excellent low dielectric properties, making the copper-clad laminate processable. In addition, the presence of internal pores in the silica further optimizes its dielectric properties, enabling it to meet the low dielectric constant and low dielectric loss requirements of high-frequency, high-speed copper-clad laminates.

[0024] Furthermore, the silica provided in this application forms strong chemical bonds and mechanical interlocking structures with the resin through the chemical bonds of the modifier, thereby further increasing the peel strength of the copper clad laminate. Specifically, the peel strength of the copper clad laminate can be increased to 1.45 N / mm, thereby making the copper clad laminate processable. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a scanning electron microscope image of the silicon dioxide prepared in Example 1 of this application; Figure 2 This is a scanning electron microscope image of the silicon dioxide prepared in Example 4 of this application; Figure 3 This is a scanning electron microscope (SEM) image showing the maximum width of the recessed surface of the first particle in the silica prepared in Example 1 of this application; Figure 4 This is a scanning electron microscope image of the silica prepared in Comparative Example 2 of this application; Figure 5 The infrared characterization spectrum of the silica prepared in Example 1 of this application; Figure 6 The XRD pattern of silica prepared in Example 1 of this application; Figure 7 The image shows the XRF analysis results of the silica prepared in Example 1 of this application. Detailed Implementation

[0027] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] This application provides a silicon dioxide comprising a first particle having at least one recessed area on its surface and a second particle having no recessed area on its surface.

[0029] For the first particle, the recessed area should be understood as a region existing on the first particle and extending to a certain depth into the particle relative to the surface of the first particle. It is the region surrounded by openings of a certain depth formed on the surface of the first particle during the preparation of silicon dioxide.

[0030] Specifically, the surface of the first particle may have one or more recessed areas.

[0031] In this application, the recessed area is formed by the outward escape of air bubbles inside the particles during the calcination process of preparing silicon dioxide. Therefore, the recessed area has a certain depth inside the particles.

[0032] During application, because the first particle has a recessed area extending to a certain depth into the particle, when the first particle combines with the resin, the resin can enter the above-mentioned area to form a mortise and tenon-like structure, thereby enhancing the peel strength of the copper clad laminate.

[0033] The recessed surface should be understood as the surface of the opening in the area enclosed by the opening at the surface of the first particle.

[0034] In this application, the first particle has a diameter, and the recessed surface has a maximum width.

[0035] The maximum width of the recessed surface should be understood as the maximum width of the largest recessed surface on the surface of the first particle. When the recessed surface is circular, the maximum width is the diameter of the circle; when the recessed surface is non-circular, the maximum width is the maximum straight-line distance between two points on the recessed surface.

[0036] In this application, the maximum width is not less than 3% of the diameter and not more than 85% of the diameter. During application, the bonding force between silica and resin is stronger, resulting in higher peel strength of the copper-clad laminate. Specifically, the peel strength is >1.0 N / mm.

[0037] For example, the maximum width can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 65%, 70%, 75%, 80%, 85%, etc.

[0038] Preferably, the maximum width is not less than 5% of the diameter and not more than 50% of the diameter, and the peel strength of the copper clad laminate prepared by the silica particles can reach up to 1.34 N / mm.

[0039] Furthermore, at least a portion of the recessed area has a protrusion, which is a structure in which the recessed surface of the recessed area protrudes outward from the surface of the first particle in the circumferential direction.

[0040] In this application, during the calcination process of preparing silicon dioxide, air bubbles inside the particles escape outward, resulting in at least some of the recessed areas having protrusions. The protrusions are areas on the surface of the recessed area that exhibit a slight outward tilt, flare, or other structure and are located at the edge of the recessed area. These protrusions can further improve the bonding force between silicon dioxide and resin, thereby further enhancing the peel strength of the copper-clad laminate.

[0041] Furthermore, the protrusion forms an angle with the recessed surface, and the angle can be an acute angle, a right angle, or an obtuse angle.

[0042] The second particle does not have the recessed area of ​​the first particle on its surface, and there are no openings of a certain depth from the particle surface to the particle interior. Nor are there any protrusions extending circumferentially outward from the recessed surface of the first particle. The surface of the second particle is relatively regular and can be understood as a "complete particle." It should be understood that this "complete particle" is only relative to the first particle with openings of a certain depth on its surface; it does not require the particle surface to be without defects. Minor damage or defects also fall within the category of "complete particles."

[0043] To better balance the high peel strength and low dielectric properties of copper clad laminates, the number or ratio of the first particle with a surface depression and the second particle without a surface depression needs to be controlled within a certain range.

[0044] In this application, the proportion of the first particle with a depression region on the surface of the silicon dioxide in the silicon dioxide particles is controlled within the range of ≤50%, which enables the prepared copper-clad laminate to have both high peel strength and excellent low dielectric properties, thus making the copper-clad laminate processable.

[0045] For example, the percentage of the first particle in the silica particles can be 50%, 45%, 40%, 45%, 35%, 30%, 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, etc.

[0046] Preferably, the proportion of the first particle in the silica particles is controlled within the range of 10-50%, and the peel strength of the copper clad laminate prepared therefrom can reach 1.23N / mm-1.45N / mm, the dielectric constant is reduced to 3.16F / m-3.50F / m, and the dielectric loss is reduced to 0.002-0.004.

[0047] When the proportion of the first particle in silica is greater than 50%, the overall proportion of silica with surface depressions is relatively high, which leads to a sharp increase in slurry viscosity, thus hindering subsequent processing.

[0048] In this application, the silicon dioxide particles also have pores inside. Specifically, both the first and second particles have pores inside. The pores inside the particles ensure that the copper-clad laminate has excellent low dielectric properties.

[0049] Specifically, the porous structure inside silica resembles a hierarchical structure, namely a network structure composed of countless tiny pillars and beams, filled with regular or irregular pores. This structure ensures that when silica particles are subjected to external forces, the stress is not concentrated at a single point or along a single line, but rather distributed across countless connection points and pillars throughout the porous network structure, with the load being "shared." During deformation, the internal pillars of the porous network structure sequentially undergo elastic bending, plastic yielding, or fracture. This process can absorb a large amount of energy, while the stress level remains near a relatively low plateau stress. Therefore, the silica of this application is not prone to collapse.

[0050] Because air has a dielectric constant of 1 and silicon dioxide has a dielectric constant of 4.2, porous silicon dioxide particles generally exhibit superior dielectric properties compared to solid silicon dioxide particles. The silicon dioxide particles provided in this application have several pores internally, and therefore can be considered as a mixture of air and silicon dioxide, i.e., composite particles formed by a silicon dioxide network framework and air filling the pores within the silicon dioxide network framework. Thus, the dielectric constant of the silicon dioxide is comprehensively provided by the air in the cavities and the silicon dioxide framework, satisfying the standard of Dk ≤ 3.5 F / m.

[0051] Furthermore, the pore diameter of the internal pores of the silicon dioxide is 0.7%-20% of the diameter of the first or second particle, and the spacing between adjacent pores is greater than 0 and less than or equal to 500 nm.

[0052] In some embodiments, the first or second particle may be spherical or near-spherical, wherein near-spherical refers to a sphericity of less than 1.

[0053] In some embodiments, the purity of the silicon dioxide is ≥99%, and the content of magnetic impurities in the silicon dioxide is ≤5ppm.

[0054] Metallic impurities in resin matrices can create numerous defects and interfaces. The disordered atomic arrangement at these point defects and interfaces acts as a "trap" for binding charges. Under an alternating electric field, charges are repeatedly captured and released within these traps, resulting in significant energy dissipation. Simultaneously, the metal ions themselves may become new polarization centers, and their displacement polarization consumes even more energy, especially at high temperatures or high frequencies, leading to dielectric loss greater than 0.005.

[0055] Therefore, it is necessary to control the purity and magnetic impurity content of silica within the aforementioned range. The control of silica purity and magnetic impurity content provided in this application can be achieved through the raw materials used in silica synthesis and the post-synthesis washing process.

[0056] In some embodiments, the hollowness of the silicon dioxide is 0.6-2.0.

[0057] In this application, the hollowness of the silicon dioxide depends on the pores inside the silicon dioxide and the recessed area on the surface of the first particle. Controlling the hollowness within the above range can ensure the stability of the silicon dioxide skeleton and prevent it from collapsing, as well as ensure excellent low dielectric properties.

[0058] In some embodiments, the silica has a particle size of 0.2-20 μm.

[0059] In some embodiments, the BET of the silica is ≤60 m² / g.

[0060] In some embodiments, the conductivity of the silicon dioxide is ≤20 μS / cm.

[0061] This application also provides a method for preparing silicon dioxide, comprising the following steps: (1) Add silicon source, surfactant, ethanol and pure water to the reaction vessel, stir, add acid and distill under reduced pressure to obtain silica prepolymer; (2) Add the silica prepolymer obtained in step (1) and pure water to the reactor, add ammonia, wash after reaction, spray dry, calcine, disperse to obtain silica.

[0062] In some embodiments, the mass ratio of silica prepolymer to pure water in step (2) is 1:(5-30).

[0063] In this application, after the silicon source is hydrolyzed in step (1), under acidic conditions, the silanol groups can also undergo a condensation reaction with the hydroxyl groups at the end of the surfactant to form Si-OC bonds, thereby grafting the surfactant chain onto the growing silica oligomer network in the form of covalent bonds.

[0064] The distillation process removes the reaction byproducts ethanol and some water, forcing the hydrolysis and condensation reaction equilibrium to shift to the right, promoting the transformation of oligomers into higher molecular weight prepolymers, thereby forming silica prepolymers.

[0065] In step (2), initially, when the silica prepolymer is dispersed in pure water, the system is relatively homogeneous (on a microscopic scale). As the ammonia-catalyzed condensation reaction proceeds rapidly, the crosslinking density of the silica network (inorganic phase) increases dramatically. This newly formed silica network is highly polar and hydrophilic. Although the surfactant chains grafted onto the network have hydrophilic segments, their terminal groups are hydrophobic, and the entire surfactant chain is thermodynamically incompatible with the forming dense inorganic silica network. This incompatibility leads to a spinolysis process, causing the system to separate into two interpenetrating phases: a silica-rich network phase and a surfactant- and water-rich phase. The condensation reaction is very fast, and the silica network rapidly gels and solidifies, "freezing" this interpenetrating bicontinuous phase structure in place.

[0066] During the later drying process, the surfactant-rich and aqueous phases are removed, leaving behind a network of countless tiny pillars and beams in the space originally occupied by them, filled with regular or irregular pores.

[0067] During the dispersion of the prepolymer in the aqueous phase, the droplets spontaneously form spherical shapes to minimize their surface energy. As rapid condensation and phase separation processes occur inside the droplets, the spherical shape is fixed by the rapidly solidifying silica network. Thus, the final product is spherical particles, which internally "encapsulate" a foam-like porous structure created by phase separation.

[0068] The applicant discovered that by adjusting the ratio of prepolymer to water, the thermodynamic and kinetic parameters of the system can be changed to achieve a dynamic balance between "internal breakthrough force" and "surface resistance".

[0069] When the prepolymer ratio is high (and the aqueous phase ratio is low), the resulting silica particles tend to be pore-free or closed-cell. This is likely because when the prepolymer is dispersed in a small amount of water, both the initial silica concentration and the surfactant PEG concentration in the dispersed phase (prepolymer droplets) are very high. Upon addition of ammonia, the high concentration of silanol groups (Si-OH) leads to an exceptionally rapid condensation reaction, causing the entire microsphere to gel within a very short time, and the network to be quickly "frozen." Due to the rapid gelation, the PEG segments do not have enough time to migrate, aggregate, and form large PEG-rich phase regions before being trapped in the dense silica network. The surface also solidifies rapidly, forming a hard but potentially brittle shell, tending to synthesize dense, solid spheres or microspheres containing numerous nanoscale closed-cell (micropore) structures with smooth, pore-free surfaces.

[0070] When the prepolymer ratio is very low (and the aqueous phase ratio is very high): the formed silica particles tend to form large-area collapses or irregular pores. This may be because the prepolymer is diluted with a large amount of water, resulting in very low concentrations of silica precursor and PEG within the dispersed phase droplets. This significantly reduces the condensation reaction rate, leading to very slow network formation. PEG has ample time to migrate and aggregate, potentially causing two consequences: 1. Excessively large phase regions: The formed PEG-rich phase regions are too large, resulting in huge internal cavities. 2. Insufficient network strength: The slowly forming silica network framework may become sparse and fragile due to the low precursor concentration, resulting in extremely slow surface curing. It remains soft and highly elastic for a long time, and may even fail to form a complete dense skin. The enormous internal expansion force acting on the weak framework may cause the entire microsphere to collapse or deform not just locally, but as a whole, rather than with localized pores.

[0071] Therefore, it is necessary to control the ratio of prepolymer to water to 1:(5-30) to control the proportion of the first particle and the hollowness of silica.

[0072] For example, the ratio of prepolymer to water can be 1:5, 1:5.5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:26, 1:27, 1:28, 1:29, 1:29.5, 1:30, etc.

[0073] In this application, when the ratio of prepolymer to water is less than 1:30, that is, the water phase ratio is too high, the proportion of the first particle is >50%, and the overall proportion of silica with surface depressions is high, which leads to a sharp increase in the viscosity of the slurry, which is not conducive to subsequent processing.

[0074] When the ratio of prepolymer to water exceeds 1:5, i.e. the water phase ratio is too low, the prepared silica particles have almost no pores or the particles are in a closed-cell state close to solid spheres. The hollowness decreases sharply, which leads to an increase in dielectric constant Dk, and does not meet the low dielectric constant index of high-frequency and high-speed copper clad laminates.

[0075] Further, in step (1), the mass ratio of silicon source, surfactant, ethanol and pure water is (80-100):(1-10):5:5.

[0076] For example, the mass ratio of silicon source, surfactant, ethanol, and pure water can be 80:1:5:5, 80:2:5:5, 80:5:5:5, 80:9:5:5, 80:10:5:5, 85:1:5:5, 85:2:5:5, 85:5:5:5, 85:9:5:5, 85:10:5:5, 90:1:5:5, 90:2 :5:5, 90:5:5:5, 90:2:9:5, 90:10:5:5, 95:1:5:5, 95:2:5:5, 95:5:5:5, 95:9:5:5, 95:10:5:5, 100:1:5:5, 100:2:5:5, 100:5:5:5, 100:9:5:5, 100:10:5:5, etc.

[0077] In this application, after the silicon source, surfactant, ethanol and pure water are added to the reactor in step (1), the temperature is controlled at 30-40℃, the stirring speed is controlled at 300-400r / min, and the stirring is carried out for 15-30min to fully dissolve the material until it becomes transparent and forms a homogeneous phase.

[0078] Further, in step (1), acid is added to control the pH of the solution to 4-5, and the reaction is continued to be stirred for 30-60 minutes.

[0079] Further, the silicon source in step (1) is selected from one of SiY4, RSiY4, R2SiY2 (where R represents an organic group in which carbon atoms are directly bonded to silicon atoms, and Y represents a monovalent hydrolytic group that generates hydroxyl groups through hydrolysis).

[0080] Furthermore, the surfactant in step (1) is selected from one of the following: nonionic "hydrophilic-hydrophobic" amphiphilic molecules, PEG-type, and glycosyl-type.

[0081] The applicant has discovered that since the rich surfactant and aqueous phase are key to pore formation and structure guidance, the mass ratio of silicon source to surfactant (80-100): (1-10) can control the hollowness of silicon dioxide. In this application, after the silica prepolymer and pure water are added to the reactor in step (2), the temperature is controlled at 30-40℃, the stirring speed is controlled at 300-400r / min, and the stirring is carried out for 15-30min. Then, ammonia water is added dropwise, the pH is controlled at 10-11, and the stirring reaction is continued for 120-240min.

[0082] Furthermore, in step (2), after the ammonia water is added and reacted, the mixture is washed with pure water to remove magnetic impurities and ions, and the conductivity of the slurry is controlled to be ≤20μS / cm.

[0083] Furthermore, in step (2), the spray drying equipment parameters are set as follows: inlet temperature 120°C, outlet temperature 180°C, to obtain a powder material with good flowability.

[0084] Further, the calcination in step (2) is as follows: the spray-dried powder material is heated to 800-1000℃ at a heating rate of 0.5-1℃ / min and held for 60-180min; then heated to 900-1100℃ at a heating rate of 0.5-1℃ / min and held for 120-240min; finally, it is naturally cooled down to obtain calcined silicon dioxide.

[0085] In this application, a two-stage calcination method is adopted: the first calcination, holding at 900℃ for 120 minutes, is mainly to remove organic matter inside the silica and strengthen the overall skeleton. The second calcination, holding at 1000℃ for 180 minutes, is mainly to densify the surface of the spheres and increase their compressive strength.

[0086] Furthermore, the dispersion in step (2) includes, but is not limited to, the following method: controlling the pressure of the silica ultrafine fractionation gas flow to 0.4 MPa to obtain monodisperse silica.

[0087] Furthermore, the preparation method further includes a modification step of modifying the monodisperse silica with a modifier, wherein the modifier is Y(CH2)3Si(OR)3, wherein Y is selected from at least one of amino, epoxy, vinyl, phenyl, and perfluoroalkyl, and R is selected from at least one of methyl and ethyl.

[0088] Furthermore, the mass of the modifier is 0.5%-2% of the mass of the porous silica.

[0089] In this application, monodisperse silica is added to a high-speed mixing equipment, the rotation speed is controlled at 300 rpm / min, so that the powder is stirred up and down in the equipment, the temperature is controlled at 80°C, and the modifier is evenly sprayed onto the powder through a pressure spraying device. The modifier is added within 10 minutes, and the reaction is continuously heated and stirred for 30 minutes to obtain the silica described in this application.

[0090] In this application, the unmodified silica surface contains hydroxyl groups (Si-OH), making it hydrophilic, while the resin matrix (such as epoxy resin) in the copper clad laminate is usually a hydrophobic resin. Direct mixing of the two results in poor compatibility, with silica easily agglomerating and difficult to disperse. The coupling agent molecule acts as a bridge; the alkoxy group (hydrolyzable group) at one end reacts chemically with the hydroxyl group on the silica surface to form a strong covalent bond (Si-O-Si); the functional groups (such as amino groups, epoxy groups, etc.) at the other end react with or physically entangle with the resin molecules, thus tightly binding the two together. This effectively prevents silica agglomeration, ensuring uniform dispersion in the resin, reducing system viscosity, and improving processing fluidity. The amount of modifier used is not necessarily better the more it is used, but rather requires precise control to achieve the best monolayer coating effect. The following formula is generally used for calculation: The mass of the modifier = the mass of silica * BET (silica) / S (minimum coating area of ​​the modifier).

[0091] The peel strength of copper-clad laminate is increased to 1.45 N / mm by the chemical bonds and mechanical interlocking structure formed by the modifier with the resin, which is much higher than the peel strength of hollow spherical silica (0.87 N / mm), thus making the copper-clad laminate processable.

[0092] This application also provides a resin composition obtained by reacting the silica with a resin and a curing agent.

[0093] Furthermore, the viscosity of the resin composition is 500-2000 mPa·s.

[0094] In this application, the mass ratio of the silicon dioxide, the resin, and the curing agent is 40:60:12.

[0095] For example, the resin is at least one of epoxy resin, bismaleimide, cyanate ester, polytetrafluoroethylene, polyphenylene ether, and benzoxazine.

[0096] In this application, the curing agent is an anhydride-type curing agent.

[0097] Specifically, the anhydride-type curing agent is selected from at least one of phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, and methylcyclohexane tetracarboxylic anhydride.

[0098] This application also provides an application of a silica or resin composition, the application including electronic components or functional materials.

[0099] Specifically, the electronic component is selected from one of the following: semiconductor device, copper-clad laminate, integrated circuit, electronic chip, radio frequency device, flexible display device, antenna device, flexible wiring device, and sensor device.

[0100] Specifically, the functional material is selected from one of advanced encapsulation materials, thermal insulation materials, and lightweight materials.

[0101] In order to enable those skilled in the art to clearly understand the above-described implementation details and operations of this application, and to demonstrate the significant improvement in the performance of the electrolyte provided by the embodiments of this application, the above technical solutions are illustrated below through examples.

[0102] Example 1 (1) Preparation of silicon dioxide S1. Add tetraethyl orthosilicate, methyl-PEG24-amine (CAS No. 2151823-08-2, brand: Wengjiang Reagent), ethanol and pure water into the reactor at a mass ratio of 80:5:5:5. Control the temperature at 30℃ and the stirring speed at 300r / min. Stir for 30min to allow the materials to fully dissolve until transparent and form a homogeneous phase. S2. Add hydrochloric acid to control pH=4, and continue stirring for 60 minutes. S3. Increase the temperature to 80℃, and remove the ethanol by vacuum distillation of the reaction solution to obtain silica prepolymer; S4. Add the prepolymer and pure water to the reactor at a mass ratio of 1:30. Control the temperature at 30℃ and the stirring speed at 300r / min. Stir for 30min, add ammonia dropwise, control the pH at 10, and continue stirring for 240min. S5. Wash the reaction solution with pure water to remove magnetic impurities and ions, and control the slurry conductivity to ≤20μS / cm. S6. The slurry is spray-dried. The spray equipment parameters are set as follows: inlet temperature 120℃, outlet temperature 180℃, to obtain a powder material with good flowability. S7. The powder material is calcined at a heating rate of 0.5℃ / min, and held at 800℃ for 180min; then heated to 900℃ and held for 240min; and then cooled naturally to obtain primary silica particles. S8. The pressure of the ultrafine gas flow for primary silica particles is controlled to 0.4 MPa to obtain monodisperse silica.

[0103] S9. Add monodisperse silica to a high-speed mixing equipment, control the speed at 300 rpm / min and the temperature at 80℃, and follow the mass ratio of modifier 3-(phenylamino)propyltrimethoxysilane to monodisperse silica of 5:1000. Spray the modifier evenly onto the powder using a pressure spraying device. Add the modifier within 10 minutes, and continue heating and stirring for 30 minutes to obtain silica with a particle size of 0.2-20μm.

[0104] (2) Preparation of resin composition Silica, bisphenol A type epoxy resin (model: GELR128E, Guangzhou Huisheng Chemical), and anhydride type curing agent (model: MTHPA-600, Guangzhou Huisheng Chemical) were added to a planetary mixer at a mass ratio of 40:60:12 and stirred for 30 minutes at a speed of 2000 rpm. The mixture was then subjected to three three-roll milling processes to obtain a uniformly mixed resin composition.

[0105] (3) Preparation of copper clad laminate Type 2116 glass fiber cloth is impregnated in a resin mixture, removed, and dried at 110°C for 2 minutes to obtain a semi-cured sheet; Three prepreg sheets are stacked together, and copper foil is placed on both the top and bottom surfaces. The sheets are then hot-pressed at 190°C and 35 MPa for 2.5 hours to obtain a copper-clad laminate.

[0106] Example 2 (1) Preparation of silicon dioxide S1. Add tetraethyl orthosilicate, methyl-PEG24-amine (CAS No. 2151823-08-2, brand: Wengjiang Reagent), ethanol and pure water into the reactor at a mass ratio of 90:7:5:5. Control the temperature at 35℃ and the stirring speed at 350r / min. Stir for 25min to allow the materials to fully dissolve until transparent and form a homogeneous phase. S2. Add hydrochloric acid to control pH=4, and continue stirring for 40 minutes. S3. Increase the temperature to 80℃, and remove the ethanol by vacuum distillation of the reaction solution to obtain silica prepolymer; S4. Add the prepolymer and pure water to the reactor at a mass ratio of 1:20. Control the temperature at 35℃ and the stirring speed at 350r / min. Stir for 25min, add ammonia dropwise, control the pH at 10, and continue stirring for 180min. S5. Wash the reaction solution with pure water to remove magnetic impurities and ions, and control the slurry conductivity to ≤20μS / cm. S6. The slurry is spray-dried. The spray equipment parameters are set as follows: inlet temperature 120℃, outlet temperature 180℃, to obtain a powder material with good flowability. S7. The powder material is calcined at a heating rate of 0.5℃ / min, and held at 900℃ for 120min; then heated to 1000℃ and held for 180min; and then cooled naturally to obtain primary silica particles. S8. The pressure of the ultrafine gas flow for primary silica particles is controlled to 0.4 MPa to obtain monodisperse silica.

[0107] S9. Add monodisperse silica to a high-speed mixing equipment, control the speed at 300 rpm / min and the temperature at 80℃, and follow the mass ratio of modifier 3-(phenylamino)propyltrimethoxysilane to monodisperse silica of 5:1000. Spray the modifier evenly onto the powder using a pressure spraying device. Add the modifier within 10 minutes, and continue heating and stirring for 30 minutes to obtain silica with a particle size of 0.2-20μm.

[0108] (2) Preparation of resin composition Silica, bisphenol A type epoxy resin (model: GELR128E, Guangzhou Huisheng Chemical), and anhydride type curing agent (model: MTHPA-600, Guangzhou Huisheng Chemical) were added to a planetary mixer at a mass ratio of 40:60:12 and stirred for 30 minutes at a speed of 2000 rpm. The mixture was then subjected to three three-roll milling processes to obtain a uniformly mixed resin composition.

[0109] (3) Preparation of copper clad laminate Type 2116 glass fiber cloth is impregnated in a resin mixture, removed, and dried at 110°C for 2 minutes to obtain a semi-cured sheet; Three prepreg sheets are stacked together, and copper foil is placed on both the top and bottom surfaces. The sheets are then hot-pressed at 190°C and 35 MPa for 2.5 hours to obtain a copper-clad laminate.

[0110] Example 3 (1) Preparation of silicon dioxide S1. Add tetraethyl orthosilicate, methyl-PEG24-amine (CAS No. 2151823-08-2, brand: Wengjiang Reagent), ethanol and pure water into the reactor at a mass ratio of 95:10:5:5. Control the temperature at 40℃ and the stirring speed at 400r / min. Stir for 15min to allow the materials to fully dissolve until transparent and form a homogeneous phase. S2. Add hydrochloric acid to control pH=5, and continue stirring for 30 minutes. S3. Increase the temperature to 80℃, and remove the ethanol by vacuum distillation of the reaction solution to obtain silica prepolymer; S4. Add the prepolymer and pure water to the reactor at a mass ratio of 1:10. Control the temperature at 40℃ and the stirring speed at 400r / min. Stir for 15min, add ammonia dropwise, control the pH at 11, and continue stirring for 120min. S5. Wash the reaction solution with pure water to remove magnetic impurities and ions, and control the slurry conductivity to ≤20μS / cm. S6. The slurry is spray-dried. The spray equipment parameters are set as follows: inlet temperature 120℃, outlet temperature 180℃, to obtain a powder material with good flowability. S7. The powder material is calcined at a heating rate of 1℃ / min, and held at 1000℃ for 60min; then heated to 1100℃ and held for 120min; and then cooled naturally to obtain primary silica particles. S8. The pressure of the ultrafine gas flow for primary silica particles is controlled to 0.4 MPa to obtain monodisperse silica.

[0111] S9. Add monodisperse silica to a high-speed mixing equipment, control the speed at 300 rpm / min and the temperature at 80℃, and follow the mass ratio of modifier 3-(phenylamino)propyltrimethoxysilane to monodisperse silica of 5:1000. Spray the modifier evenly onto the powder using a pressure spraying device. Add the modifier within 10 minutes, and continue heating and stirring for 30 minutes to obtain silica with a particle size of 0.2-20μm.

[0112] (2) Preparation of resin composition Silica, bisphenol A type epoxy resin (model: GELR128E, Guangzhou Huisheng Chemical), and anhydride type curing agent (model: MTHPA-600, Guangzhou Huisheng Chemical) were added to a planetary mixer at a mass ratio of 40:60:12 and stirred for 30 minutes at a speed of 2000 rpm. The mixture was then subjected to three three-roll milling processes to obtain a uniformly mixed resin composition.

[0113] (3) Preparation of copper clad laminate Type 2116 glass fiber cloth is impregnated in a resin mixture, removed, and dried at 110°C for 2 minutes to obtain a semi-cured sheet; Three prepreg sheets are stacked together, and copper foil is placed on both the top and bottom surfaces. The sheets are then hot-pressed at 190°C and 35 MPa for 2.5 hours to obtain a copper-clad laminate.

[0114] Example 4 (1) Preparation of silicon dioxide S1. Add tetraethyl orthosilicate, methyl-PEG24-amine (CAS No. 2151823-08-2, brand: Wengjiang Reagent), ethanol and pure water into the reaction vessel at a mass ratio of 100:1:5:5. Control the temperature at 40℃ and the stirring speed at 400r / min. Stir for 15min to allow the materials to fully dissolve until transparent and form a homogeneous phase. S2. Add hydrochloric acid to control pH=5, and continue stirring for 30 minutes. S3. Increase the temperature to 80℃, and remove the ethanol by vacuum distillation of the reaction solution to obtain silica prepolymer; S4. Add the prepolymer and pure water to the reactor at a mass ratio of 1:5. Control the temperature at 40℃ and the stirring speed at 400r / min. Stir for 15min, add ammonia dropwise, control the pH at 11, and continue stirring for 120min. S5. Wash the reaction solution with pure water to remove magnetic impurities and ions, and control the slurry conductivity to ≤20μS / cm. S6. The slurry is spray-dried. The spray equipment parameters are set as follows: inlet temperature 120℃, outlet temperature 180℃, to obtain a powder material with good flowability. S7. The powder material is calcined at a heating rate of 1℃ / min, and held at 1000℃ for 60min; then heated to 1100℃ and held for 120min; and then cooled naturally to obtain primary silica particles. S8. The pressure of the ultrafine gas flow for primary silica particles is controlled to 0.4 MPa to obtain monodisperse silica.

[0115] S9. Add monodisperse silica to a high-speed mixing equipment, control the speed at 300 rpm / min and the temperature at 80℃, and follow the mass ratio of modifier 3-(phenylamino)propyltrimethoxysilane to monodisperse silica of 5:1000. Spray the modifier evenly onto the powder using a pressure spraying device. Add the modifier within 10 minutes, and continue heating and stirring for 30 minutes to obtain silica with a particle size of 0.2-20μm.

[0116] (2) Preparation of resin composition Silica, bisphenol A type epoxy resin (model: GELR128E, Guangzhou Huisheng Chemical), and anhydride type curing agent (model: MTHPA-600, Guangzhou Huisheng Chemical) were added to a planetary mixer at a mass ratio of 40:60:12 and stirred for 30 minutes at a speed of 2000 rpm. The mixture was then subjected to three three-roll milling processes to obtain a uniformly mixed resin composition.

[0117] (3) Preparation of copper clad laminate Type 2116 glass fiber cloth is impregnated in a resin mixture, removed, and dried at 110°C for 2 minutes to obtain a semi-cured sheet; Three prepreg sheets are stacked together, and copper foil is placed on both the top and bottom surfaces. The sheets are then hot-pressed at 190°C and 35 MPa for 2.5 hours to obtain a copper-clad laminate.

[0118] Comparative Example 1 Silica was prepared according to the method in Example 1, but the vacuum distillation treatment described in step S3 was not performed, resulting in the formation of a gel. Subsequent experiments could not be conducted.

[0119] Comparative Example 2 Silica, resin composition, and copper-clad laminate were prepared sequentially according to the preparation method of Example 1. The mass ratio of prepolymer to pure water was replaced with 1:35.

[0120] Comparative Example 3 Silica, resin composition, and copper-clad laminate were prepared sequentially according to the preparation method in Example 1. The mass ratio of prepolymer to pure water was replaced with 1:4.

[0121] The silica prepared in Examples 1-4 and Comparative Examples 1-3 was tested for hollowness, percentage of first particles, percentage of maximum width of the concave surface to the particle diameter, purity, magnetic impurity content, particle size, BET, and conductivity. Specific test methods are shown below, and the results are presented in Table 1. Figures 1-4 The data shown.

[0122] 1. Hollowness The true density test method for powders is the specific gravity bottle method.

[0123] Hollowness = (Silica density - Air density) / Porous silica density.

[0124] The density of solid spherical silicon is 2.22 g / cm³. 3 The density of air is 1 g / cm³ 3 The density of porous silica was measured by the specific gravity bottle method.

[0125] 2. Percentage of the first particle The silica sample was prepared and photographed using SEM at a magnification of 2000. Five images were taken from five different locations. ImageJ was used to convert the SEM images into 8-bit grayscale images. The SEM images were manually annotated, and the spheres were classified as "intact" or "depressed." The percentage of the first type of particle (particles with depressions on the surface) was calculated.

[0126] 3. The percentage of the maximum width of the largest indentation surface of the first particle to the particle diameter. The silica sample was photographed using SEM at a magnification of 5000. The maximum width of the largest depression in each first particle in the SEM image and the diameter of the first particle containing the depression were measured using a scale. The ratio of the maximum width to the particle diameter was then calculated.

[0127] 4. Purity First, XRD testing was performed: X-ray diffraction was used to confirm that the silicon dioxide described in this application is amorphous silicon dioxide. Equipment used: Bruker XRD D8 Advance.

[0128] Next, XRF testing was performed: the purity value was obtained using an X-ray fluorescence spectrometer. This is equivalent to qualitative analysis followed by quantitative analysis. Equipment used: Bruker XRF S8 Tiger.

[0129] 5. Magnetic impurity content The water-soluble magnetic rod (≥8000GS) adsorption method was used for measurement. Specifically, 250g of silica powder was weighed and diluted with 1L of water. The magnetic rod was placed in the container and immersed in the mixture. After adsorption for half an hour, it was taken out, and the impurities adsorbed on the magnetic rod were removed. The impurity content was obtained by weighing using a 1 / 100,000 analytical balance by the weight reduction method.

[0130] 6. Particle size Particle size was determined using an MS-3000+ laser particle size analyzer.

[0131] 7. BET The processing temperature was 160℃ / 300℃, and the specific surface area of ​​nitrogen adsorption was measured using a Bestech fully automatic nitrogen adsorption specific surface area analyzer.

[0132] 8. Electrical conductivity The powder conductivity was tested using a four-probe method powder conductivity meter.

[0133] Table 1. Relevant Tests for Silica

[0134] The silica prepared in Example 1 was characterized by FT-IR, XRD, and XRF. The relevant spectra and results are shown in [reference needed]. Figures 5-7 .

[0135] Figure 5 Medium (3200-3600cm) -1 There are no strong and broad OH stretching vibration peaks, but there are a small number of saturated CH stretching vibrations (such as sp³C-H, 2800-3000 cm⁻¹). -1 (1500-1600cm) -1 The double peaks (1000-1100 cm⁻¹) are typical characteristic peaks of aromatic ring skeletal vibration. -1The peak (<1000 cm⁻¹) is a characteristic peak of the Si-O-Si stretching vibration. -1 The presence of multiple sharp peaks of moderate intensity corresponds to characteristic peaks of Si-O bending vibration, COC, or other single-bond bending vibrations. This indicates that phenylmethyl functional groups have been successfully grafted onto the silica surface.

[0136] Viscosity tests were performed on the resin compositions prepared in Examples 1-4 and Comparative Examples 1-3. Peel strength, Dk, and Df tests were performed on the prepared copper-clad laminates. The specific test methods are shown below, and the data are shown in Table 2.

[0137] 1. Viscosity Rotational viscometer method 2. Peel strength The copper-clad laminate was cut into 50mm×50mm×1mm samples and tested according to IPC TM-650 2.4.8.

[0138] 3. Dielectric properties (Dk, Df) The copper-clad laminate was cut into 50mm×50mm×1mm samples and tested according to IPC TM-650 2.5.5.5 (using 10GHz).

[0139] Table 2. Relevant Tests for Resin Compositions and Copper Clad Laminates

[0140] As can be seen from Tables 1 and 2, the copper-clad laminate formed by silicon dioxide containing both a first particle with a recessed region and a second particle without a recessed region, as provided in this application, can achieve a peel strength of over 1.23 N / mm, a dielectric constant of less than 3.5 F / m under the test condition of 10 GHz, and an extremely low dielectric loss of less than 0.004, thus achieving an excellent balance between peel strength and dielectric performance.

[0141] Furthermore, as can be seen from Examples 1-4, the higher the proportion of the first particle, the greater the ratio of the maximum width of the recessed surface to the diameter of the first particle, resulting in higher hollowness. The copper-clad laminate prepared using this method achieves both low dielectric constant and low dielectric loss, while also exhibiting higher peel strength, reaching a maximum of 1.45 N / mm. In practical applications, the proportion of the first particle in the silica particles can be adjusted as needed to meet the requirements of high-frequency, high-speed copper-clad laminates (Dk≤3.5F / m and Df≤0.005).

[0142] In Comparative Example 2, the proportion of the first particle in the silica particles is higher than 50%, the ratio of the maximum width of the concave surface to the diameter of the first particle is as high as 90%, and the specific surface area of ​​the particles is significantly increased, reaching 90 μm². 2The / g value may be due to the following reasons: A high water phase ratio leads to easier formation of depressions and even an increase in their width. This results in easier formation of the first particle, and an increase in the ratio of the maximum width of the depression to the diameter of the first particle. Because of the increased depression width, the proportion of a single depression area on the silica particles is too high, directly resulting in the collapse of the silica particles. This significantly increases the specific surface area of ​​the silica particles, leading to excessively high slurry viscosity, making it impossible to fabricate copper-clad laminates. Consequently, the dielectric properties cannot be measured, failing to meet the requirements for high-frequency, high-speed copper-clad laminates.

[0143] In Comparative Example 3, the number of first particles in the silica particles is relatively small, and the ratio of the maximum width of the recessed surface to the diameter of the first particle is also small. The copper-clad laminate prepared with this method has a high dielectric constant of 3.98 F / m. This may be because: the proportion of water phase is too low, making it difficult to form recessed surfaces; and the hollowness of the silica particles is very low. The degree of hollowness determines the dielectric properties of silica particles; higher hollowness results in a lower dielectric constant, and vice versa. The peel strength of the copper-clad laminate is relatively low, at 1.00 N / mm. This may be because: the number of recessed surfaces and their proportion on the silica surface are reduced; the insufficient protrusions of the recessed surfaces cannot achieve sufficient bonding strength with the resin, resulting in a relatively low peel strength for the prepared copper-clad laminate. Therefore, these silica particles cannot meet the requirements for high-frequency, high-speed copper-clad laminates.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A type of silicon dioxide, characterized in that, The silicon dioxide includes a first particle with at least one recessed area on its surface and a second particle without a recessed area on its surface, wherein the first particle has a diameter; The recessed area extends inward along the surface of the first particle, and each recessed area forms a recessed surface on the surface of the first particle. The recessed surface has a maximum width, and the maximum width is not greater than 85% of the diameter. The first particle accounts for 10-50% of the total number of particles; Wherein, the maximum width of the concave surface is the maximum width of the largest concave surface in the first particle; The silica has pores inside, and the diameter of the pores is 0.7%-20% of the diameter of the first or second particle.

2. The silicon dioxide according to claim 1, characterized in that, At least a portion of the recessed area has a protrusion that bulges outward along the surface of the first particle in the circumferential direction of the recessed surface formed on the surface of the first particle.

3. The silicon dioxide according to claim 2, characterized in that, The protrusion forms an angle with the concave surface, and the angle is an acute angle, a right angle, or an obtuse angle.

4. The silicon dioxide according to claim 1, characterized in that, The first particle and / or the silicon dioxide is spherical or near-spherical.

5. The silicon dioxide according to claim 1, characterized in that, The maximum width of the concave surface of the first particle is not greater than 50% of the particle diameter; and / or, The first particle accounts for 1%-50% of the total number of particles.

6. The silicon dioxide according to any one of claims 1-5, characterized in that, The spacing between adjacent pores of the silicon dioxide is greater than 0 and less than or equal to 500 nm.

7. The silicon dioxide according to claim 6, characterized in that, The silicon dioxide satisfies one or more of the following conditions: (1) The purity of the silicon dioxide is ≥99%; (2) The content of magnetic impurities in the silica is ≤5ppm; (3) The hollowness of the silica is 0.6-2.0; (4) The silica particle size is 0.2-20 μm; (5) The BET of the silicon dioxide is ≤60m² / g; (6) The conductivity of the silicon dioxide is ≤20μS / cm.

8. A method for preparing silicon dioxide according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Preparation of prepolymer: Silica prepolymer is prepared by vacuum distillation using raw materials containing silicon source; (2) Preparation of silicon dioxide: The silicon dioxide was obtained by calcination; The process includes a step of mixing the silica prepolymer with water before calcination.

9. The method for preparing silicon dioxide according to claim 8, characterized in that, Step (1) further includes an acid treatment step before vacuum distillation, whereby the pH of the solution is controlled to be 4-5 after the acid is added; and / or, In step (2), water is added and mixed at a mass ratio of silica prepolymer to water of 1:(5-30); and / or The step (2) after water treatment also includes an alkali treatment step to control the pH of the reaction solution to 10-11.

10. The method for preparing silicon dioxide according to claim 8, characterized in that, The calcination conditions in step (2) are as follows: heat to 800-1000℃ at a heating rate of 0.5-1℃ / min and hold for 60-180min; then heat to 900-1100℃ at a heating rate of 0.5-1℃ / min and hold for 120-240min.

11. The method for preparing silicon dioxide according to claim 9, characterized in that, The raw materials mentioned in step (1) include: a silicon source, a surfactant, ethanol, and water, in a mass ratio of (80-100):(1-10):5:5; and / or, The alkali mentioned in step (2) is ammonia.

12. The method for preparing silicon dioxide according to any one of claims 8-11, characterized in that, The preparation method further includes a modification step of modifying the silica using a modifier, wherein the modifier is Y(CH2)3Si(OR)3, wherein Y is selected from at least one of amino, epoxy, vinyl, phenyl, and perfluoroalkyl groups, and R is selected from at least one of methyl and ethyl groups, and / or, The mass of the modifier is 0.5%-2% of the mass of the silicon dioxide.

13. A resin composition, characterized in that, The resin composition is obtained by reacting the silica prepared by any one of claims 1-7 or by any one of claims 8-12 with a resin and a curing agent.

14. The resin composition according to claim 13, characterized in that, The mass ratio of the silica, the resin, and the curing agent is 40:60:12, and / or the resin is at least one of epoxy resin, bismaleimide, cyanate ester, polytetrafluoroethylene, polyphenylene ether, and benzoxazine, and the curing agent is an anhydride-type curing agent; and / or The viscosity of the resin composition is 500-2000 mPa·s.

15. The use of a silica according to any one of claims 1-7, or a silica prepared by the preparation method according to any one of claims 8-12, or a resin composition according to any one of claims 13-14, characterized in that, The application includes electronic components or functional materials, wherein the electronic components are one of semiconductor devices, copper-clad laminates, integrated circuits, electronic chips, radio frequency devices, flexible display devices, antenna devices, flexible wiring devices, and sensor devices, and the functional materials are one of advanced packaging materials, thermal insulation materials, and lightweight materials.

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