A low-loss high-frequency carrier board and its manufacturing method

Abstract

This invention discloses a low-loss, high-frequency carrier board and its manufacturing method, relating to the field of packaging carrier board technology. The carrier board of this invention comprises, from bottom to top, a substrate, a transition layer, a circuit board, an insulating layer, and a functional coating; wherein, the substrate comprises, from bottom to top, a ceramic layer, a dielectric layer, and a copper foil layer; the dielectric layer adopts a polyimide resin composite system to ensure excellent dielectric properties; the modified bismaleimide-cyanate in the functional coating achieves efficient heat dissipation and reliable protection by introducing modified boron nitride and modified silicon dioxide. The carrier board obtained by this invention has comprehensive advantages such as low dielectric loss, high signal integrity, strong interlayer bonding, and good thermal stability, making it suitable for packaging high-frequency, high-power electronic devices.

Description

Technical Field

[0001] This invention relates to the field of packaging substrate technology, specifically to a low-loss high-frequency substrate and its manufacturing method. Background Technology

[0002] With the rapid development of 5G, IoT, and AI technologies, electronic devices are evolving towards higher frequencies and higher power densities, placing stringent requirements on chip packaging substrates for low dielectric loss, high heat dissipation, and high interface reliability. Currently, packaging substrates suffer from the following shortcomings: 1. Traditional polymer materials (such as FR-4) have high dielectric loss, making it difficult to meet high-frequency requirements, while low-loss materials such as PTFE have poor adhesion to metals, resulting in insufficient mechanical strength and heat resistance; 2. High thermal conductivity fillers are prone to agglomeration and have weak interfacial bonding with resin, easily leading to stress cracking of the substrate; 3. Inefficient heat dissipation paths make it difficult to dissipate concentrated heat, causing equipment overheating.

[0003] Therefore, in order to solve the above problems, the present invention proposes a low-loss high-frequency carrier plate and its manufacturing method. Summary of the Invention

[0004] The purpose of this invention is to provide a low-loss high-frequency carrier board and its manufacturing method to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A low-loss high-frequency carrier board comprises, from bottom to top, a substrate, a transition layer, a circuit board, an insulating layer, and a functional coating; the substrate comprises, from bottom to top, a ceramic layer, a dielectric layer, and a copper foil layer.

[0006] Furthermore, the ceramic layer is aluminum nitride ceramic or silicon nitride ceramic.

[0007] Furthermore, the substrate has a thickness of 50-100 μm, and the thickness ratio of the ceramic layer, dielectric layer and copper foil layer in the substrate is 1:(0.6-0.8):(0.5-0.8); the transition layer has a thickness of 3-5 μm; the circuit board has a thickness of 40-80 μm; the insulating layer has a thickness of 5-10 μm; and the functional coating has a thickness of 5-10 μm.

[0008] Furthermore, the dielectric layer is obtained by coating with a dielectric layer paste, which includes the following components by mass: 30-80 parts of polyimide resin, 6-12 parts of aluminum nitride, 3-8 parts of silicon dioxide, and 40-80 parts of N-methylpyrrolidone.

[0009] Furthermore, the transition layer is one or more of Ni, Zn, Ti, Al, and Mg.

[0010] Furthermore, the insulating layer is obtained by coating with an insulating layer slurry, which includes the following components by mass: 30-50 parts of bisphenol A type epoxy resin, 15-30 parts of methyltetrahydrophthalic anhydride, 20-30 parts of silica, 5-10 parts of boron nitride, and 20-30 parts of acetone.

[0011] Furthermore, the functional coating is obtained by coating with a functional coating slurry, which includes the following components by mass: 25-40 parts of modified bismaleimide-cyanate, 0.5-1.5 parts of silane coupling agent, and 30-50 parts of ethylene glycol methyl ether; the silane coupling agent selected is KH-550. Modified bismaleimide-cyanate is prepared by the following process: bismaleimide, cyanate, and allylphenol compounds are placed in a reaction vessel and stirred at 120-160℃ for 2-3 hours to obtain a prepolymer; the prepolymer, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, and modified silica are added to butanone, stirred at 3000-5000 rpm for 20-40 minutes, and then ultrasonically treated. The sound power was 500-1000W, and the time was 20-40min to obtain modified bismaleimide-cyanate ester; the mass ratio of bismaleimide, cyanate ester, allylphenol compound, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, modified silica and butanone was (10-25):(25-40):(5-15):(0.1-2):(5-10):(10-15):(3-5):(50-80); Modified boron nitride was prepared by the following process: Boron nitride nanosheets were dispersed in Tris-HCl buffer at pH 8.5, dopamine hydrochloride was added, and the mixture was slowly stirred at room temperature for 12-24 h. After centrifugation, washing, and drying, polydopamine-modified boron nitride nanosheets (PDA@BNNS) were obtained. PDA@BNNS were dispersed in N-methylpyrrolidone solvent, and amino-terminated hyperbranched polysiloxane was added. The mixture was reacted at 60-80 °C for 6-10 h. After centrifugation, washing, and drying, modified boron nitride was obtained. Boron nitride nanosheets and Tris-HCl were then prepared. The mass ratio of HCl buffer, dopamine hydrochloride, solvent N-methylpyrrolidone, and terminal amino hyperbranched polysiloxane is 1:(50-80):(0.05-0.1):(20-50):(0.1-0.3); the centrifugation, washing, and drying process conditions are as follows: first, centrifuge at a speed of 6000-9000 rpm for 10-15 min, then wash with deionized water 3-5 times, and then dry at a vacuum of -0.05 MPa to -0.08 MPa and a temperature of 60-80℃ for 18-24 h; Modified silica is prepared by the following process: Spherical silica is dispersed in anhydrous ethanol, 3-glycidoxypropyltrimethoxysilane is added, and the mixture is reacted at 70-80℃ for 6-8 hours. After centrifugation, washing, and vacuum drying, activated silica with epoxy groups on its surface is obtained. The activated silica is then dispersed in dimethylformamide, hyperbranched polyethyleneimine is added, and the mixture is reacted at 80-90℃ for 12-24 hours. After centrifugation, washing, and vacuum drying, modified silica is obtained. Spherical silica, 3... The mass ratio of glycidyloxypropyltrimethoxysilane, dimethylformamide, and hyperbranched polyethyleneimine is 10:(0.3-0.5):(50-80):(1-2); the process conditions for centrifugation, washing, and vacuum drying are as follows: first, centrifuge at a speed of 8000-12000 rpm for 10-15 min, then wash with anhydrous ethanol 3-5 times, and then dry at a vacuum of -0.05 MPa to -0.08 MPa and a temperature of 60-80℃ for 12-24 h.

[0012] A method for manufacturing a low-loss high-frequency carrier board includes the following steps: S1: Select aluminum nitride ceramic or silicon nitride ceramic, clean it sequentially with acetone and ethanol in an ultrasonic cleaner for 25-30 minutes, rinse with deionized water, and dry it with nitrogen gas for later use; prepare dielectric layer slurry, disperse it at high speed and ball mill it, then coat it onto the ceramic surface, and cure it under a gradient temperature under a nitrogen protective atmosphere; use hot pressing to fix copper foil to the dielectric layer surface to prepare the substrate; S2: Take the transition layer material, use EB vapor deposition method, and micronize the transition layer material at an energy of 0.8-1.5eV. Then, the micronized material is adsorbed onto the copper foil layer to form the transition layer. S3: Lay the circuit board on top of the transition layer and use hot pressing to press and fix the circuit board to the substrate; S4: Prepare the insulating layer slurry, stir it magnetically until it is evenly dispersed, apply it to the surface of the circuit board, and cure it to form an insulating layer; prepare the functional coating slurry, stir it magnetically until the polymer is evenly dispersed, apply it to the surface of the insulating layer, and cure it to form a functional coating.

[0013] Furthermore, in step S1, the process conditions for high-speed dispersion and ball milling are as follows: high-speed dispersion speed is 8000-12000 rpm, time is 25-35 min, and ball milling time is 1-3 h. The gradient temperature curing process conditions are as follows: under a nitrogen protective atmosphere, react at 80-100℃ for 1-2 hours, then at 100-120℃ for 1-2 hours, and finally at 160-180℃ for 2-3 hours.

[0014] Furthermore, in steps S1 and S3, the hot pressing process conditions are: temperature 300-350℃, time 3-6min, and pressure 6-10MPa.

[0015] Furthermore, in step S4, the magnetic stirring speed is 400-600 rpm; The curing process conditions are as follows: first, preheat at 70-80℃ for 30-45 minutes, then react at 180-200℃ for 80-120 minutes, and then cure at 230-250℃ for 150-180 minutes.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention describes a low-loss high-frequency carrier plate and its manufacturing method. The functional coating of the present invention uses modified bismaleimide-cyanate as the matrix material. Through the prepolymer synthesis stage, the low dielectric properties of cyanate are combined with the high heat resistance of bismaleimide, and allylphenol compounds are introduced to enhance toughness, thereby significantly improving its heat resistance and mechanical properties while maintaining low dielectric loss. Subsequently, by incorporating modified boron nitride and modified silica, it forms a chemically bonded three-dimensional interpenetrating network with the resin during the crosslinking process. This not only constructs an efficient heat conduction path to accelerate heat diffusion, but also ensures that it still has excellent signal integrity in the high-frequency environment.

[0017] 2. The present invention describes a low-loss high-frequency carrier plate and its manufacturing method. In a modified bismaleimide-cyanate ester system, boron nitride is modified by: firstly, a polydopamine layer is formed on the surface of boron nitride nanosheets through dopamine self-polymerization, which has strong adhesion and abundant active groups; then, terminal amino hyperbranched polysiloxane is grafted, and its steric hindrance effect is used to prevent the nanosheets from recombinizing, thereby achieving stable dispersion of modified boron nitride in solvents and resins; and the terminal amino hyperbranched polysiloxane has excellent flexibility, which can effectively absorb, buffer and disperse stress when the carrier plate is subjected to force or heat.

[0018] 3. The low-loss high-frequency carrier plate and its manufacturing method described in this invention, in the modified bismaleimide-cyanate ester system, the modified silica undergoes two-step surface treatment: firstly, epoxy groups are introduced through 3-glycidoxypropyltrimethoxysilane, and then hyperbranched polyethyleneimine is grafted to make its surface rich in amine groups. These amine groups can chemically react with the resin matrix to change the silica from a physically filled state to a chemically bonded state, which significantly improves its dispersibility in the system. Moreover, the hyperbranched polyethyleneimine has excellent flexibility, and can effectively absorb, buffer and disperse stress when the carrier plate is subjected to force or heat.

[0019] 4. The present invention describes a low-loss high-frequency carrier board and its manufacturing method. The present invention constructs a dual heat dissipation mechanism of "substrate-functional coating": the substrate is based on high thermal conductivity aluminum nitride / silicon nitride ceramic, establishing an efficient vertical heat conduction path from the chip to the substrate; the functional coating is based on modified bismaleimide-cyanate ester, which has high in-plane thermal conductivity and can quickly diffuse and conduct heat laterally; this synergistic heat dissipation structure significantly improves the overall thermal management capability of the carrier board, ensuring the stability and reliability of high-power chips during long-term operation.

[0020] 5. The present invention describes a low-loss high-frequency carrier board and its manufacturing method. The substrate of the present invention uses a high thermal conductivity ceramic layer to absorb heat, a dielectric layer to conduct heat, and a copper foil layer to uniformly heat the substrate laterally, forming a vertical heat conduction channel; a transition layer reduces the thermal resistance at the interface between the substrate and the circuit board and buffers thermal stress; the circuit board balances the heat of multiple chips, and the insulating layer achieves insulation without blocking heat, forming an intermediate heat dissipation relay; the functional coating constructs a high thermal conductivity network, which rapidly diffuses and releases heat laterally, and the multi-layer structure works together to improve the heat dissipation capacity of the carrier board. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following specific implementation: All numbers below refer to parts by weight, unless otherwise specified.

[0023] Modified boron nitride was prepared by the following process: boron nitride nanosheets were dispersed in Tris-HCl buffer solution at pH 8.5, dopamine hydrochloride was added, and the mixture was slowly stirred at room temperature for 15 h. After centrifugation, washing, and drying, polydopamine-modified boron nitride nanosheets (PDA@BNNS) were obtained. PDA@BNNS were dispersed in N-methylpyrrolidone solvent, and terminal amino hyperbranched polysiloxane was added. The mixture was reacted at 70 °C for 8 h. After centrifugation, washing, and drying, modified boron nitride was obtained. The mass ratio of boron nitride nanosheets, Tris-HCl buffer solution, dopamine hydrochloride, N-methylpyrrolidone solvent, and terminal amino hyperbranched polysiloxane was 1:60:0.08:30:0.2. The centrifugation, washing, and drying conditions were as follows: centrifugation at 8000 rpm for 12 min, followed by washing with deionized water four times, and then drying at a vacuum of -0.05 MPa and a temperature of 70 °C for 18 h. Modified silica was prepared by the following process: spherical silica was dispersed in anhydrous ethanol, 3-glycidoxypropyltrimethoxysilane was added, and the mixture was reacted at 70°C for 6 hours. After centrifugation, washing, and vacuum drying, activated silica with epoxy groups on its surface was obtained. The activated silica was dispersed in dimethylformamide, hyperbranched polyethyleneimine was added, and the mixture was reacted at 80°C for 12 hours. After centrifugation, washing, and vacuum drying, modified silica was obtained. The mass ratio of spherical silica, 3-glycidoxypropyltrimethoxysilane, dimethylformamide, and hyperbranched polyethyleneimine was 10:0.4:50:1. The centrifugation, washing, and vacuum drying conditions were as follows: centrifugation at 9000 rpm for 12 minutes, followed by washing with anhydrous ethanol four times, and then drying at a vacuum of -0.05 MPa and a temperature of 60°C for 12 hours. Aluminum nitride ceramic: thermal conductivity 170 W / (m·K), coefficient of thermal expansion 4.6 × 10⁻⁶ -6 / K (40-400℃), dielectric constant is 8.5 (1MHz); silicon nitride ceramic: thermal conductivity is 36W / (m·K), coefficient of thermal expansion is 1.6×10 -6 / K (25-200℃); Aluminum nitride particle size is 10μm; Silica particle size is 50nm; Spherical silica particle size is 20nm; Purity of 3-glycidoxypropyltrimethoxysilane is 98%; Purity of dimethylformamide is 99.5%; Average molecular weight of hyperbranched polyethyleneimine is 25000; Purity of N-methylpyrrolidone is 99.9%; N, The purity of N-dimethylacetamide was 99.8%; the particle size of boron nitride was 50 nm; boron nitride nanosheets had a diameter of 2 μm and a thickness of 50 nm; the pH of the Tris-HCl buffer was 8.5, and the concentration was 10 mM; the purity of dopamine hydrochloride was 98.5%; the purity of the terminal amino hyperbranched polysiloxane was 98%; the purity of the cyanate ester was 99%; the CAS number of bismaleimide was 13676-54-5; the allylphenol compound used was 2-allylphenol with a purity of 98%; catalyst 2 The purity of ethyl-4-methylimidazolium was 99%; the average molecular weight of polyethylene glycol was 6000; the purity of butanone was 98%; the purity of acetone was 99.5%; the purity of ethanol was 99.8%; the thickness of copper foil was 15 μm; the purity of ethylene glycol methyl ether was 99%; the purity of nickel block was 99.95%, purchased from Hebei Ruichi New Materials Co., Ltd.; the circuit board was purchased from Jiangsu Punowei Electronics Co., Ltd.; the CAS number of bisphenol A type epoxy resin was 107-21-1; and the purity of methyltetrahydrophthalic anhydride was 95%.

[0024] Example 1: A low-loss high-frequency carrier board, comprising, from bottom to top, a substrate, a transition layer, a circuit board, an insulating layer, and a functional coating; the substrate includes an aluminum nitride ceramic layer, a dielectric layer, and a copper foil layer; the substrate has a thickness of 80 μm, and the thickness ratio of the ceramic layer, dielectric layer, and copper foil layer in the substrate is 1:0.7:0.6; the transition layer has a thickness of 5 μm; the circuit board has a thickness of 50 μm; the insulating layer has a thickness of 8 μm; and the functional coating has a thickness of 8 μm. The dielectric layer is obtained by coating with a dielectric layer paste, which includes the following components by mass: 50 parts polyimide resin, 8 parts aluminum nitride, 5 parts silicon dioxide, and 50 parts N-methylpyrrolidone. The transition layer is a Ni layer; the insulating layer is obtained by coating with an insulating layer slurry, which includes the following components by mass: 40 parts of bisphenol A type epoxy resin, 20 parts of methyltetrahydrophthalic anhydride, 25 parts of silicon dioxide, 8 parts of boron nitride, and 25 parts of acetone. The functional coating is obtained by applying a functional coating slurry, which includes the following components by mass: 30 parts modified bismaleimide-cyanate, 1 part silane coupling agent, and 40 parts ethylene glycol methyl ether; the silane coupling agent is selected; the modified bismaleimide-cyanate is prepared by the following process: bismaleimide, cyanate, and allylphenol compounds are placed in a reaction vessel and stirred at 140°C for 2.5 h to obtain a prepolymer; the prepolymer, catalyst 2-ethyl-4-methylimidazole, ... Polyethylene glycol, modified boron nitride, and modified silica were added to methyl ethyl ketone (MEK), stirred at 4000 rpm for 30 min, and then subjected to ultrasonic treatment at 800 W for 30 min to obtain modified bismaleimide-cyanate. The mass ratio of bismaleimide, cyanate, allylphenolic compound, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, modified silica, and MEK was 20:30:10:1:8:12:4:60. A method for manufacturing a low-loss high-frequency carrier board includes the following steps: S1: Select aluminum nitride ceramic, clean it sequentially with acetone and ethanol in an ultrasonic cleaner for 28 min, rinse with deionized water, and dry it with nitrogen for later use; prepare dielectric layer slurry, disperse it at 10000 rpm for 30 min, ball mill it for 2 h, and then coat it on the ceramic surface. Under a nitrogen protective atmosphere, react it first at 90℃ for 1.5 h, then at 110℃ for 1.5 h, and then cure it at 170℃ for 2.5 h; press and fix the copper foil and dielectric layer at 320℃ and 8MPa for 5 min to prepare the substrate; S2: Take a nickel block and use the EB vapor deposition method at an energy of 1.2 eV to micronize the nickel block and adsorb it onto the copper foil layer to form a transition layer; S3: Lay the circuit board on top of the transition layer, and press the circuit board and the substrate together at 320°C and 8MPa for 5 minutes. S4: Prepare the insulating layer slurry, stir at 500 rpm until uniformly dispersed, apply to the surface of the circuit board, and cure to form an insulating layer; prepare the functional coating slurry, stir at 500 rpm until uniformly dispersed, apply to the surface of the insulating layer, and cure to form a functional coating; the curing process conditions are: preheat at 75℃ for 40 min, react at 190℃ for 100 min, and then cure at 240℃ for 160 min.

[0025] Example 2: A low-loss high-frequency carrier board, comprising, from bottom to top, a substrate, a transition layer, a circuit board, an insulating layer, and a functional coating; the substrate includes an aluminum nitride ceramic layer, a dielectric layer, and a copper foil layer; the substrate has a thickness of 50 μm, and the thickness ratio of the ceramic layer, dielectric layer, and copper foil layer in the substrate is 1:0.6:0.5; the transition layer has a thickness of 3 μm; the circuit board has a thickness of 40 μm; the insulating layer has a thickness of 5 μm; and the functional coating has a thickness of 5 μm. The dielectric layer is obtained by coating with a dielectric layer paste, which includes the following components by mass: 30 parts polyimide resin, 6 parts aluminum nitride, 3 parts silicon dioxide, and 80 parts N-methylpyrrolidone. The transition layer is a Ni layer; the insulating layer is obtained by coating with an insulating layer slurry, which includes the following components by mass: 30 parts of bisphenol A type epoxy resin, 15 parts of methyltetrahydrophthalic anhydride, 20 parts of silicon dioxide, 5 parts of boron nitride, and 30 parts of acetone. The functional coating is obtained by applying a functional coating slurry, which comprises the following components by weight: 25 parts modified bismaleimide-cyanate, 0.5 parts silane coupling agent, and 50 parts ethylene glycol methyl ether; the silane coupling agent is KH-550; the modified bismaleimide-cyanate is prepared by the following process: bismaleimide, cyanate, and allylphenol compounds are placed in a reaction vessel and stirred at 120°C for 3 hours to obtain a prepolymer; the prepolymer and catalyst 2-ethyl-4-methylimidazolium are then added... Azole, polyethylene glycol, modified boron nitride, and modified silica were added to methyl ethyl ketone (MEK). The mixture was stirred at 3000 rpm for 40 min, followed by ultrasonic treatment at 500 W for 20 min to obtain modified bismaleimide-cyanate. The mass ratio of bismaleimide, cyanate, allylphenolic compounds, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, modified silica, and MEK was 10:25:5:0.1:5:10:3:50. A method for manufacturing a low-loss high-frequency carrier board includes the following steps: S1: Select silicon nitride ceramic, clean it sequentially with acetone and ethanol in an ultrasonic cleaner for 25 min, rinse with deionized water, and dry it with nitrogen for later use; prepare dielectric layer slurry, disperse it at 8000 rpm for 35 min, ball mill it for 1 h, and then coat it on the ceramic surface. Under a nitrogen protective atmosphere, react it first at 80℃ for 2 h, then at 100℃ for 2 h, and then cure it at 160℃ for 3 h; press and fix the copper foil and dielectric layer at 300℃ and 6MPa for 6 min to prepare the substrate; S2: Take a nickel block and use the EB vapor deposition method at an energy of 0.8eV to micronize the nickel block and adsorb it onto the copper foil layer to form a transition layer; S3: Lay the circuit board on top of the transition layer, and press the circuit board and the substrate together at 300°C and 6MPa for 6 minutes. S4: Prepare the insulating layer slurry, stir at 400 rpm until uniformly dispersed, apply to the surface of the circuit board, and cure to form an insulating layer; prepare the functional coating slurry, stir at 400 rpm until uniformly dispersed, apply to the surface of the insulating layer, and cure to form a functional coating; the curing process conditions are: preheat at 70℃ for 45 min, then react at 180℃ for 120 min, and then cure at 230℃ for 180 min.

[0026] Example 3: A low-loss high-frequency carrier board, comprising, from bottom to top, a substrate, a transition layer, a circuit board, an insulating layer, and a functional coating; the substrate includes an aluminum nitride ceramic layer, a dielectric layer, and a copper foil layer; the substrate has a thickness of 100 μm, and the thickness ratio of the ceramic layer, dielectric layer, and copper foil layer in the substrate is 1:0.8:0.8; the transition layer has a thickness of 5 μm; the circuit board has a thickness of 80 μm; the insulating layer has a thickness of 10 μm; and the functional coating has a thickness of 10 μm. The dielectric layer is obtained by coating with a dielectric layer paste, which includes the following components by mass: 80 parts of polyimide resin, 12 parts of aluminum nitride, 8 parts of silicon dioxide, and 40 parts of N-methylpyrrolidone. The transition layer is a Ni layer; the insulating layer is obtained by coating with an insulating layer slurry, which includes the following components by mass: 50 parts of bisphenol A type epoxy resin, 30 parts of methyltetrahydrophthalic anhydride, 30 parts of silicon dioxide, 10 parts of boron nitride, and 20 parts of acetone. The functional coating is obtained by applying a functional coating slurry, which comprises the following components by mass: 40 parts modified bismaleimide-cyanate, 1.5 parts silane coupling agent, and 30 parts ethylene glycol methyl ether; the silane coupling agent is KH-550; the modified bismaleimide-cyanate is prepared by the following process: bismaleimide, cyanate, and allylphenol compounds are placed in a reaction vessel and stirred at 160°C for 2 hours to obtain a prepolymer; the prepolymer and the catalyst 2-ethyl-4-methylimidazole are then added... Polyethylene glycol, modified boron nitride, and modified silica were added to butanone and stirred at 5000 rpm for 20 min. Then, the mixture was ultrasonically treated with an ultrasonic power of 1000 W for 20 min to obtain modified bismaleimide-cyanate. The mass ratio of bismaleimide, cyanate, allylphenolic compound, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, modified silica, and butanone was 25:40:15:2:10:15:5:80. A method for manufacturing a low-loss high-frequency carrier board includes the following steps: S1: Select aluminum nitride ceramic, clean it sequentially with acetone and ethanol in an ultrasonic cleaner for 30 minutes, rinse with deionized water, and dry it with nitrogen for later use; prepare dielectric layer slurry, disperse it at 12000 rpm for 25 minutes, ball mill it for 3 hours, and then coat it on the ceramic surface. Under a nitrogen protective atmosphere, react it first at 100℃ for 1 hour, then at 120℃ for 1 hour, and then cure it at 180℃ for 2 hours to form a dielectric layer; press and fix the copper foil and dielectric layer at 350℃ and 10MPa for 3 minutes to obtain the copper foil layer; S2: Take a nickel block and use the EB vapor deposition method at an energy of 1.5eV to micronize the nickel block and adsorb it onto the copper foil layer to form a transition layer; S3: Lay the circuit board on top of the transition layer, and press the circuit board and the substrate together at 350°C and 10MPa for 3 minutes. S4: Prepare the insulating layer slurry, stir at 600 rpm until uniformly dispersed, apply to the surface of the circuit board, and cure to form an insulating layer; prepare the functional coating slurry, stir at 600 rpm until uniformly dispersed, apply to the surface of the insulating layer, and cure to form a functional coating; the curing process conditions are: preheat at 80℃ for 30 min, react at 200℃ for 80 min, and then cure at 250℃ for 150 min.

[0027] Comparative Example 1: Based on Example 1, the modified bismaleimide-cyanate in the functional coating was replaced with bismaleimide.

[0028] Comparative Example 2: Based on Example 1, the modified boron nitride and modified silica in the modified bismaleimide-cyanate were replaced with boron nitride modified with silane coupling agent KH-550 and silica modified with silane coupling agent KH-550.

[0029] Comparative Example 3: Based on Example 1, the modified bismaleimide-cyanate ester in the functional coating was replaced with cyanate ester resin.

[0030] Experiment: Samples were prepared from the carrier plates obtained in Examples 1-3 and Comparative Examples 1-3, and their performance was tested and the results were recorded. Thermal conductivity test: The sample was processed into a disc with a diameter of 10 mm and a thickness of 2 mm using the laser flash method. In a vacuum environment, the front side of the sample was instantaneously heated by a laser pulse, and the temperature change curve of the back side over time was recorded by an infrared detector. The thermal diffusivity was calculated. The thermal conductivity was derived by combining the sample density and specific heat capacity. Thermal conductivity = thermal diffusivity × density × specific heat capacity. Peel strength test: A 90° peel test was conducted at a tensile rate of 300 mm / min. The maximum force during the peel process was recorded, and the peel strength per unit width (N / mm) was calculated. Each sample was tested three times and the average value was taken. Heat release test: The samples were placed in an environment of 100℃ for 1 hour, then removed and left to stand at room temperature for 10 minutes before the temperature of each sample was measured. Dielectric constant and dielectric loss: Measured using SPDR (split dielectric resonator) at a test frequency of 10 GHz.

[0031] Table 1. Test results for examples and comparative examples.

[0032] Conclusion: As can be seen from the comparison of the data in the table, the carrier plates prepared in Examples 1-3 of the present invention are significantly better than those in Comparative Examples 1-3 in terms of thermal conductivity, peel strength and heat release temperature. Comparative Examples 1-3, based on Example 1, showed significantly inferior carrier performance compared to Examples 1-3. In Comparative Example 1, replacing the modified bismaleimide-cyanate in the functional coating with bismaleimide resulted in a significant decrease in carrier performance, indicating that bismaleimide cannot construct an effective thermal conductive network, and its high polarity leads to severe dielectric polarization loss at high frequencies, failing to meet the core requirements of heat dissipation and low signal loss for high-frequency, high-power devices. In Comparative Example 2, the modified bismaleimide-cyanate incorporated boron nitride modified with silane coupling agent KH-550 and silicon dioxide modified with silane coupling agent KH-550. The performance of the prepared carrier board was significantly reduced, indicating that simple KH-550 modification cannot meet the stringent requirements of high-frequency and high-power carrier boards for interface reliability, heat dissipation efficiency, and signal integrity. However, this invention achieves strong bonding, high dispersion, and tough buffering at the filler-resin interface through dopamine-assisted hyperbranched polymer interface engineering, which is the key to the breakthrough in carrier board performance. In Comparative Example 3, the modified bismaleimide-cyanate in the functional coating was replaced with cyanate resin. This made the functional coating only have basic insulation and protection functions, but almost no active heat dissipation capabilities. It could not dissipate the heat generated by the chip in time, resulting in a significant decline in heat release performance. In summary, the carrier board of this invention, through innovative material selection and systematic collaborative design of functional coatings, successfully solves the three interrelated core challenges of low signal loss, high interface reliability, and efficient heat dissipation in high-frequency and high-power packaging, fully meeting the urgent needs of next-generation advanced electronic packaging for carrier board technology.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A low-loss high-frequency carrier board, characterized in that: From bottom to top, it includes a substrate, a transition layer, a circuit board, an insulating layer, and a functional coating; the substrate includes a ceramic layer, a dielectric layer, and a copper foil layer from bottom to top.

2. The low-loss high-frequency carrier board according to claim 1, characterized in that: The dielectric layer is obtained by coating with a dielectric layer paste, which includes the following components by mass: 30-80 parts of polyimide resin, 6-12 parts of aluminum nitride, 3-8 parts of silicon dioxide, and 40-80 parts of N-methylpyrrolidone.

3. The low-loss high-frequency carrier board according to claim 1, characterized in that: The transition layer is one or more of Ni, Zn, Ti, Al, and Mg.

4. The low-loss high-frequency carrier board according to claim 1, characterized in that: The functional coating comprises the following components by weight: 25-40 parts of modified bismaleimide-cyanate, 0.5-1.5 parts of silane coupling agent, and 30-50 parts of ethylene glycol methyl ether.

5. A low-loss high-frequency carrier board according to claim 4, characterized in that: The modified bismaleimide-cyanate ester is prepared by the following process: bismaleimide, cyanate ester, and allylphenol compounds are placed in a reaction vessel and reacted with stirring at 120-160℃ for 2-3 hours to obtain a prepolymer; the prepolymer, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, and modified silica are added to butanone, stirred at 3000-5000 rpm for 20-40 minutes, and then subjected to ultrasonic treatment. The modified bismaleimide-cyanate was obtained by ultrasonic power of 500-1000W and time of 20-40min. The mass ratio of bismaleimide, cyanate, allylphenol compound, catalyst 2-ethyl-4-methylimidazolium, polyethylene glycol, modified boron nitride, modified silica and butanone was (10-25):(25-40):(5-15):(0.1-2):(5-10):(10-15):(3-5):(50-80).

6. A low-loss high-frequency carrier board according to claim 5, characterized in that: The modified boron nitride was prepared by the following process: boron nitride nanosheets were dispersed in Tris-HCl buffer solution at pH 8.5, dopamine hydrochloride was added, and the mixture was slowly stirred at room temperature for 12-24 h. After centrifugation, washing, and drying, polydopamine-modified boron nitride nanosheets (PDA@BNNS) were obtained. PDA@BNNS were dispersed in the solvent N-methylpyrrolidone, and terminal amino hyperbranched polysiloxane was added. The mixture was reacted at 60-80 °C for 6-10 h. After centrifugation, washing, and drying, modified boron nitride was obtained.

7. A low-loss high-frequency carrier board according to claim 5, characterized in that: The modified silica is prepared by the following process: spherical silica is dispersed in anhydrous ethanol, 3-glycidoxypropyltrimethoxysilane is added, and the mixture is reacted at 70-80℃ for 6-8 hours. After centrifugation, washing, and vacuum drying, activated silica with epoxy groups on the surface is obtained. The activated silica is dispersed in dimethylformamide, hyperbranched polyethyleneimine is added, and the mixture is reacted at 80-90℃ for 12-24 hours. After centrifugation, washing, and vacuum drying, modified silica is obtained.

8. A low-loss high-frequency carrier board according to claim 1, characterized in that: The ceramic layer is aluminum nitride ceramic or silicon nitride ceramic.

9. A low-loss high-frequency carrier board according to claim 1, characterized in that: The substrate has a thickness of 50-100 μm, and the thickness ratio of the ceramic layer, dielectric layer and copper foil layer in the substrate is 1:(0.6-0.8):(0.5-0.8); the transition layer has a thickness of 3-5 μm; the circuit board has a thickness of 40-80 μm; the insulating layer has a thickness of 5-10 μm; and the functional coating has a thickness of 5-10 μm.

10. A method for manufacturing a low-loss high-frequency carrier plate according to any one of claims 1-9, characterized in that: Includes the following steps: S1: Select aluminum nitride ceramics or silicon nitride ceramics, clean them in an ultrasonic cleaner with acetone and ethanol for 25-30 minutes in sequence, rinse with deionized water, and dry with nitrogen for later use; prepare dielectric layer slurry, and after high-speed dispersion and ball milling, coat it onto the ceramic surface and cure it under a nitrogen protective atmosphere with gradient temperature rise. A substrate is prepared by hot pressing to fix copper foil onto the surface of the dielectric layer. S2: Take the transition layer material, use EB vapor deposition method, and micronize the transition layer material at an energy of 0.8-1.5eV. Then, the micronized material is adsorbed onto the copper foil layer to form the transition layer. S3: Lay the circuit board on top of the transition layer and use hot pressing to press and fix the circuit board to the substrate; S4: Prepare the insulating slurry, stir it magnetically until it is evenly dispersed, coat it on the surface of the circuit board, and cure it to form an insulating layer; The functional coating slurry is prepared, magnetically stirred until the polymer is uniformly dispersed, coated on the surface of the insulating layer, and cured to form a functional coating.

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