A method for preparing high-frequency ultrathin copper-clad laminate

Abstract

This invention discloses a method for preparing high-frequency ultrathin copper-clad laminates, belonging to the field of high-frequency copper-clad laminate preparation technology. The steps include preparation of the base solution, activation of the coupling agent, dispersion of the filler, blending of fluororesin, casting and high-temperature sintering, and vacuum hot pressing for copper cladding. Through the synergistic effect of compound coupling agents, compound fillers, and compound additives, the prepared copper-clad laminate has a dielectric constant of only 2.72 and a dielectric loss factor of 0.000286 at 10 GHz, exhibiting excellent dimensional stability. This method solves the problems of poor dielectric properties and dimensional instability of existing high-frequency copper-clad laminates, making it suitable for high-frequency electronics and showing good application prospects.

Description

Technical Field

[0001] This invention relates to the field of high-frequency copper clad laminate preparation technology, and in particular to a method for preparing high-frequency ultrathin copper clad laminate. Background Technology

[0002] PTFE-based copper-clad laminates are a core substrate for high-frequency / high-speed PCBs. They are typically made by impregnating electronic fiberglass cloth with PTFE resin, cladding copper foil on one or both sides, and then hot-pressing at high temperature. They possess excellent dielectric properties, thermal stability, and chemical stability, making them a key foundational material for 5G / 6G communications, millimeter-wave radar, satellite communications, and RF and microwave devices. As electronic devices continue to upgrade towards higher frequencies, higher speeds, thinner profiles, and higher integration, the requirements for dielectric layer thickness, signal transmission loss, and dimensional accuracy of circuit boards are constantly increasing. Ultra-thin designs, low losses, and high dimensional stability have become the core development directions of the industry.

[0003] To achieve thinner substrates and superior high-frequency transmission performance, the industry is gradually abandoning traditional fiberglass reinforcement structures and shifting towards a fiberglass-free, pure-filler ultrathin PTFE-based copper clad laminate (CCL) technology. Fiberglass-free structures effectively avoid the problems associated with fiberglass, such as increased dielectric constant, increased loss, and limited thickness. This makes it easier to fabricate ultrathin sheets of less than 2 mil, or even less than 1 mil, meeting the dual requirements of thinness and low loss in high-frequency, high-speed circuits, leading to rapid market demand growth. However, fiberglass-free, pure-filler PTFE substrates have inherent, insurmountable defects: PTFE resin itself has a high coefficient of linear thermal expansion, insufficient rigidity, and high high-temperature sintering shrinkage. After removing the fiberglass reinforcement, the substrate's dimensional stability deteriorates drastically, easily leading to significant shrinkage, warping, and excessive dimensional drift upon heating. This directly results in misalignment, circuit breakage, and lamination misalignment in subsequent PCB manufacturing processes, significantly reducing production yield and product reliability.

[0004] Existing technologies typically employ single inorganic powder fillers and modification with common silane coupling agents, making it difficult to simultaneously resolve the contradictions between filler dispersibility, interfacial bonding, dielectric loss, and dimensional stability. Conventional amino-based silane coupling agents have poor compatibility with PTFE, leading to filler agglomeration and resulting in high dielectric loss; simply increasing the filler content, on the other hand, causes decreased adhesive stability, difficulty in casting, and increased brittleness of the sheets. Currently, there is still a lack of a complete fabrication technology for fiberglass-free, purely filled PTFE-based copper clad laminates that can simultaneously achieve ultra-thin thickness, ultra-low loss, high dimensional stability, and good formability, becoming a key bottleneck restricting the development of high-frequency ultra-thin substrates. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing high-frequency ultrathin copper-clad laminates. Through formulation and process design, it significantly improves component compatibility, interfacial bonding, and dimensional stability, achieving integrated preparation of ultrathin, ultra-low-loss, and highly dimensionally stable materials.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing high-frequency ultrathin copper-clad laminates, comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 280-350 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 280-350 r / min for 20-30 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2, and nano monoclinic ZrO2 sequentially while stirring at a speed of 2400-2600 r / min. Disperse at high speed for 50-70 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 280-350 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 30-40 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 35-45 min, and then let it stand at a constant temperature of 25-30℃ for 40-50 h to obtain the adhesive solution; Step S5, Casting and High-Temperature Sintering: Adjust the viscosity of the adhesive solution to 340-360 CPS with deionized water, and uniformly coat it onto a mirror stainless steel strip using a casting machine; dry with hot air at 68-72℃ for 23-28 min, sinter at 390-420℃ for 5-10 min, and peel off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.5±0.1 mil; Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

[0007] Preferably, the propylene glycol polyether surfactant in step S1 is propylene glycol block polyether L-61.

[0008] Preferably, the mass ratio of deionized water to propylene glycol polyether surfactant in step S1 is 100:(3-5).

[0009] Preferably, the mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is (10³-10⁵):3:(1-2).

[0010] Preferably, the fluoroalkylsiloxane oligomer in step S2 is SiSiB® FF9020-1000 fluorinated silicone oil.

[0011] Preferably, the high-purity silicon powder mentioned in step S3 is 4N high-purity silicon powder with a particle size of 5000 mesh.

[0012] Preferably, the particle size of the nano-hollow SiO2 in step S3 is 300 nm; the nano-monoclinic ZrO2 is of type ZT-R80 and is provided by Zhejiang Zhitai Nano Micro New Materials Co., Ltd.

[0013] Preferably, in step S3, the mass ratio of the solution prepared in step S2, high-purity silicon micro powder, nano hollow SiO2, and nano monoclinic ZrO2 is (107-110):(100-110):8:5.

[0014] Preferably, the PTFE emulsion in step S3 is of the brand name JF-4DCA and is provided by Hangzhou Jufu New Material Technology Co., Ltd.; the PFA emulsion is Pureflon. TM PFA FC680 is provided by Hangzhou Jingfu Technology Co., Ltd.; the low molecular weight perfluoropolyether is model SL-90 and is provided by Fuzhou Taipuda New Material Co., Ltd.; the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50.

[0015] Preferably, the mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is (220-233):242:104:(1-3):(5-7).

[0016] Preferably, the copper foil in step S6 is 0.5OZ ED copper foil.

[0017] Preferably, the parameters for vacuum hot pressing in step S6 are: temperature 360-380℃, pressure 460-500PSI, and holding time 100-120min.

[0018] Another object of the present invention is to provide a high-frequency ultrathin copper-clad laminate manufactured using the above-described method for preparing high-frequency ultrathin copper-clad laminates.

[0019] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The method for preparing high-frequency ultrathin copper-clad laminate disclosed in this invention uses phenyltriethoxysilane and fluoroalkylsiloxane oligomers for activation. The phenyl structure can match the dielectric properties of PTFE, while the fluoroalkyl chain can form an affinity with the PTFE molecular chain. The synergy of the two not only solves the problem of poor compatibility between traditional coupling agents and PTFE, but also avoids the problem of filler agglomeration, so that the inorganic filler is uniformly dispersed in the resin matrix, which unexpectedly reduces dielectric loss and significantly improves the interfacial bonding strength. This solves the inherent defect of easy peeling between filler and resin in glass fiber-free structures and lays the foundation for the structural stability of ultrathin substrates.

[0020] (2) The method for preparing high-frequency ultrathin copper-clad laminate disclosed in this invention uses a combination of 4N high-purity silicon micropowder, nano-hollow SiO2, and nano-monoclinic ZrO2. High-purity silicon micropowder can reduce the overall linear thermal expansion coefficient of the substrate, while nano-hollow SiO2 alleviates the brittleness problem caused by filler agglomeration due to its hollow structure. Nano-monoclinic ZrO2 can further improve the rigidity and high-temperature resistance of the substrate. Under the synergistic effect of the three, the defect of high high-temperature sintering shrinkage of PTFE resin itself is effectively suppressed, and the problems of unstable adhesive and difficult casting film formation caused by simply increasing the amount of filler are avoided. An ultrathin uniform film of 2.5±0.1mil is successfully prepared, achieving the simultaneous achievement of ultrathin thickness and high dimensional stability, far exceeding the performance limit of existing single filler filling schemes. The hollow structure of nano-hollow SiO2 can reduce the equivalent dielectric constant and suppress dielectric loss. At the same time, it works synergistically with high-purity silicon micropowder and nano-monoclinic ZrO2 to achieve simultaneous optimization of dielectric properties, dimensional stability, and formability of high-frequency ultrathin copper-clad laminate.

[0021] (3) The method for preparing high-frequency ultrathin copper-clad laminate disclosed in this invention involves blending PTFE emulsion with PFA emulsion. The addition of PFA not only retains the excellent dielectric properties of PTFE but also improves the fluidity and moldability of the resin. With the assistance of low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, the compatibility of each component is further improved, and the casting performance of the adhesive is also improved, which greatly improves the uniformity of film thickness during the casting process. At the same time, low molecular weight perfluoropolyether can fill the gaps between resin molecules, further reducing signal transmission loss and meeting the stringent requirements of 5G / 6G high-frequency high-speed communication.

[0022] (4) The method for preparing high-frequency ultrathin copper-clad laminate disclosed in this invention, by precisely controlling the parameters of each step such as preparation of the base liquid, activation of the coupling agent, high-speed dispersion, constant temperature curing and vacuum hot pressing, makes the coupling agent more fully activated, the filler more uniformly dispersed and the resin crosslinking more thorough. It unexpectedly solves the industry pain points of glass fiber-free ultrathin substrates being prone to warping when heated and having excessive dimensional drift, and realizes the integration of ultrathin, ultra-low loss, high dimensional stability and good formability, breaking the technical bottleneck that restricts the development of high-frequency ultrathin substrates. Detailed Implementation

[0023] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0024] Example 1: A method for preparing a high-frequency ultrathin copper-clad laminate, comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 280 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 280 r / min for 20 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2 and nano monoclinic ZrO2 sequentially while stirring at a speed of 2400 r / min. Disperse at high speed for 50 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 280 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 30 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 35 min, and then let it stand at 25℃ for 40 h to obtain the adhesive solution. Step S5, Casting and High-Temperature Sintering: Adjust the viscosity of the adhesive solution to 340 CPS with deionized water, and uniformly coat it onto a mirror stainless steel strip using a casting machine; dry with hot air at 68℃ for 23 min, sinter at 390℃ for 5 min, and peel off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.5 mil. Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

[0025] The propylene glycol polyether surfactant mentioned in step S1 is propylene glycol block polyether L-61; the mass ratio of deionized water to propylene glycol polyether surfactant in step S1 is 100:3; the mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is 103:3:1; the fluoroalkylsiloxane oligomer in step S2 is SiSiB®FF9020-1000 fluorinated silicone oil; the high-purity silicon micro powder mentioned in step S3 is 4N high-purity silicon micro powder with a particle size of 5000 mesh; the particle size of the nano-hollow SiO2 mentioned in step S3 is 300nm; the nano-monoclinic ZrO2 is model ZT-R80 and is provided by Zhejiang Zhitai Nanomaterials Co., Ltd.; the mass ratio of the solution prepared in step S2, high-purity silicon micro powder, nano-hollow SiO2, and nano-monoclinic ZrO2 in step S3 is 107:100:8:5.

[0026] The PTFE emulsion mentioned in step S3 is of brand name JF-4DCA and is provided by Hangzhou Jufu New Material Technology Co., Ltd.; the PFA emulsion is Pureflon. TM PFA FC680; the low molecular weight perfluoropolyether is model SL-90, provided by Fuzhou Taipuda New Material Co., Ltd.; the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50; the mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is 220:242:104:1:5; the copper foil in step S6 is 0.5OZ ED copper foil; the parameters of the vacuum hot pressing in step S6 are: temperature 360℃, pressure 460PSI, and holding time 100min.

[0027] A high-frequency ultrathin copper-clad laminate prepared by the above-mentioned method for preparing high-frequency ultrathin copper-clad laminate.

[0028] Example 2: A method for preparing a high-frequency ultrathin copper-clad laminate, comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 300 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 300 r / min for 23 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2 and nano monoclinic ZrO2 sequentially while stirring at a speed of 2450 r / min. Disperse at high speed for 55 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 300 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 33 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 37 min, and then let it stand at 27℃ for 43 h to obtain the adhesive solution. Step S5, Casting and High-Temperature Sintering: The viscosity of the adhesive solution was adjusted to 345 CPS with deionized water and uniformly coated onto a mirror stainless steel strip using a casting machine; it was dried with hot air at 69℃ for 24 min, sintered at 400℃ for 6 min, and peeled off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.4 mil. Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

[0029] The propylene glycol polyether surfactant mentioned in step S1 is propylene glycol block polyether L-61; the mass ratio of deionized water to propylene glycol polyether surfactant in step S1 is 100:3.5; the mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is 103.5:3:1.5; the fluoroalkylsiloxane oligomer in step S2 is SiSiB®. FF9020-1000 fluorinated silicone oil; the high-purity silicon powder mentioned in step S3 is 4N high-purity silicon powder with a particle size of 5000 mesh; the particle size of the nano-hollow SiO2 mentioned in step S3 is 300 nm; the nano-monoclinic ZrO2 is of type ZT-R80 and is provided by Zhejiang Zhitai Nano-Micro New Materials Co., Ltd.; the mass ratio of the solution prepared in step S2, high-purity silicon powder, nano-hollow SiO2, and nano-monoclinic ZrO2 in step S3 is 108:103:8:5.

[0030] The PTFE emulsion mentioned in step S3 is of brand name JF-4DCA and is provided by Hangzhou Jufu New Material Technology Co., Ltd.; the PFA emulsion is Pureflon. TM PFA FC680; the low molecular weight perfluoropolyether is model SL-90, provided by Fuzhou Taipuda New Material Co., Ltd.; the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50; the mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is 224:242:104:1.5:5.5; the copper foil in step S6 is 0.5OZ ED copper foil; the parameters of the vacuum hot pressing in step S6 are: temperature 365℃, pressure 470PSI, and holding time 105min.

[0031] A high-frequency ultrathin copper-clad laminate prepared by the above-mentioned method for preparing high-frequency ultrathin copper-clad laminate.

[0032] Example 3: A method for preparing a high-frequency ultrathin copper-clad laminate, comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 320 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 320 r / min for 25 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2 and nano monoclinic ZrO2 sequentially while stirring at a speed of 2500 r / min. Disperse at high speed for 60 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 320 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 35 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 40 min, and then let it stand at 28℃ for 45 h to obtain the adhesive solution. Step S5, Casting and High-Temperature Sintering: Adjust the viscosity of the adhesive solution to 350 CPS with deionized water, and uniformly coat it onto a mirror stainless steel strip using a casting machine; dry with hot air at 70℃ for 25 min, sinter at 405℃ for 8 min, and peel off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.5 mil. Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

[0033] The propylene glycol polyether surfactant mentioned in step S1 is propylene glycol block polyether L-61; the mass ratio of deionized water to propylene glycol polyether surfactant in step S1 is 100:4; the mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is 104:3:1; the fluoroalkylsiloxane oligomer in step S2 is SiSiB®FF9020-1000 fluorinated silicone oil; the high-purity silicon powder mentioned in step S3 is 4N high-purity silicon powder with a particle size of 5000 mesh; the particle size of the nano-hollow SiO2 mentioned in step S3 is 300 nm; the nano-monoclinic ZrO2 is model ZT-R80 and is provided by Zhejiang Zhitai Nanomaterials Co., Ltd.; the mass ratio of the solution prepared in step S2, high-purity silicon powder, nano-hollow SiO2, and nano-monoclinic ZrO2 in step S3 is 108:105:8:5.

[0034] The PTFE emulsion mentioned in step S3 is of brand name JF-4DCA and is provided by Hangzhou Jufu New Material Technology Co., Ltd.; the PFA emulsion is Pureflon. TM PFA FC680; the low molecular weight perfluoropolyether is model SL-90, provided by Fuzhou Taipuda New Material Co., Ltd.; the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50; the mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is 226:242:104:2:6; the copper foil in step S6 is 0.5OZ ED copper foil; the parameters of the vacuum hot pressing in step S6 are: temperature 370℃, pressure 480PSI, and holding time 110min.

[0035] A high-frequency ultrathin copper-clad laminate prepared by the above-mentioned method for preparing high-frequency ultrathin copper-clad laminate.

[0036] Example 4: A method for preparing a high-frequency ultrathin copper-clad laminate, comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 340 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 340 r / min for 28 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2 and nano monoclinic ZrO2 sequentially while stirring at a speed of 2550 r / min. Disperse at high speed for 65 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 340 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 38 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 43 min, and then let it stand at 29℃ for 48 h to obtain the adhesive solution. Step S5, Casting and High-Temperature Sintering: The viscosity of the adhesive solution was adjusted to 355 CPS with deionized water and uniformly coated onto a mirror stainless steel strip using a casting machine; it was dried with hot air at 71℃ for 27 min, sintered at 410℃ for 9 min, and peeled off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.6 mil. Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

[0037] The propylene glycol polyether surfactant mentioned in step S1 is propylene glycol block polyether L-61; the mass ratio of deionized water to propylene glycol polyether surfactant in step S1 is 100:4.5; the mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is 104.5:3:1.5; the fluoroalkylsiloxane oligomer in step S2 is SiSiB®. FF9020-1000 fluorinated silicone oil; the high-purity silicon micro powder mentioned in step S3 is 4N high-purity silicon micro powder with a particle size of 5000 mesh; the particle size of the nano hollow SiO2 mentioned in step S3 is 300 nm; the nano monoclinic ZrO2 is model ZT-R80 and is provided by Zhejiang Zhitai Nano Micro New Materials Co., Ltd.; the mass ratio of the solution prepared in step S2, high-purity silicon micro powder, nano hollow SiO2, and nano monoclinic ZrO2 in step S3 is 109:109:8:5.

[0038] The PTFE emulsion mentioned in step S3 is of brand name JF-4DCA and is provided by Hangzhou Jufu New Material Technology Co., Ltd.; the PFA emulsion is Pureflon. TM PFA FC680; the low molecular weight perfluoropolyether is model SL-90, provided by Fuzhou Taipuda New Material Co., Ltd.; the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50; the mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is 231:242:104:2.5:6.5; the copper foil in step S6 is 0.5OZ ED copper foil; the parameters of the vacuum hot pressing in step S6 are: temperature 375℃, pressure 490PSI, and holding time 115min.

[0039] A high-frequency ultrathin copper-clad laminate prepared by the above-mentioned method for preparing high-frequency ultrathin copper-clad laminate.

[0040] Example 5: A method for preparing a high-frequency ultrathin copper-clad laminate, comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 350 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 350 r / min for 30 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2 and nano monoclinic ZrO2 sequentially while stirring at a speed of 2600 r / min. Disperse at high speed for 70 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 350 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 40 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 45 min, and then let it stand at 30℃ for 50 h to obtain the adhesive solution. Step S5, Casting and High-Temperature Sintering: Adjust the viscosity of the adhesive solution to 360 CPS with deionized water, and uniformly coat it onto a mirror stainless steel strip using a casting machine; dry with hot air at 72℃ for 28 min, sinter at 420℃ for 10 min, and peel off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.5 mil. Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

[0041] The propylene glycol polyether surfactant mentioned in step S1 is propylene glycol block polyether L-61; the mass ratio of deionized water to propylene glycol polyether surfactant in step S1 is 100:5; the mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is 105:3:2; the fluoroalkylsiloxane oligomer in step S2 is SiSiB®FF9020-1000 fluorinated silicone oil; the high-purity silicon micro powder mentioned in step S3 is 4N high-purity silicon micro powder with a particle size of 5000 mesh; the particle size of the nano-hollow SiO2 mentioned in step S3 is 300nm; the nano-monoclinic ZrO2 is model ZT-R80 and is provided by Zhejiang Zhitai Nanomaterials Co., Ltd.; the mass ratio of the solution prepared in step S2, high-purity silicon micro powder, nano-hollow SiO2, and nano-monoclinic ZrO2 in step S3 is 110:110:8:5.

[0042] The PTFE emulsion mentioned in step S3 is of brand name JF-4DCA and is provided by Hangzhou Jufu New Material Technology Co., Ltd.; the PFA emulsion is Pureflon. TM PFA FC680; the low molecular weight perfluoropolyether is model SL-90, provided by Fuzhou Taipuda New Material Co., Ltd.; the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50; the mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is 233:242:104:3:7; the copper foil in step S6 is 0.5OZ ED copper foil; the parameters of the vacuum hot pressing in step S6 are: temperature 380℃, pressure 500PSI, and holding time 120min.

[0043] A high-frequency ultrathin copper-clad laminate prepared by the above-mentioned method for preparing high-frequency ultrathin copper-clad laminate.

[0044] Comparative Example 1: A method for preparing a high-frequency ultrathin copper-clad laminate is basically the same as that in Example 5, except that an equal amount of phenyltriethoxysilane is used instead of fluoroalkylsiloxane oligomers.

[0045] Comparative Example 2: A method for preparing a high-frequency ultrathin copper-clad laminate is basically the same as that in Example 5, except that an equal amount of silane coupling agent KH550 is used instead of phenyltriethoxysilane.

[0046] Comparative Example 3: A method for preparing a high-frequency ultrathin copper-clad laminate is basically the same as that in Example 5, except that an equal amount of nano-monoclinic ZrO2 is used instead of nano-hollow SiO2.

[0047] Comparative Example 4: A method for preparing a high-frequency ultrathin copper-clad laminate is basically the same as that in Example 5, except that an equal amount of PTFE emulsion is used instead of PFA emulsion.

[0048] Comparative Example 5: A method for preparing a high-frequency ultrathin copper-clad laminate is basically the same as that in Example 5, except that an equal amount of low molecular weight perfluoropolyether is used instead of branched secondary alcohol polyoxyethylene ether.

[0049] Comparative Example 6: A method for preparing a high-frequency ultrathin copper-clad laminate is basically the same as that in Example 5, except that an equal amount of branched secondary alcohol polyoxyethylene ether is used instead of low molecular weight perfluoropolyether.

[0050] To further illustrate the beneficial technical effects of the high-frequency ultrathin copper-clad laminates prepared in the various examples of the present invention, the high-frequency ultrathin copper-clad laminates of Example 5 and Comparative Examples 1-6 were subjected to relevant performance tests using the following experimental methods. The test results are shown in Table 1: (1) Dielectric constant DK and loss factor DF: DK (SPDR@10GHZ) and DF (SPDR@10GHZ) were determined by the SPDR method according to GB / T 43801-2024.

[0051] (2) Dimensional stability: Tested according to GB / T 4722-2017, radial / weft change rate (ppm) after 150℃ / 30min.

[0052] As shown in Table 1, the high-frequency ultrathin copper-clad laminate prepared in Example 5 of this invention exhibits significantly better dielectric constant (DK=2.72), dielectric loss factor (DF=0.000286), and dimensional stability (radial -243ppm, weft -308ppm) at 10GHz than Comparative Examples 1-6. Specifically, Comparative Examples 1-6 were obtained by replacing the fluoroalkylsiloxane oligomer, phenyltriethoxysilane, nano-hollow SiO2, PFA emulsion, and branched secondary alcohol polyoxyethylene in Example 5, respectively. The test results obtained from ether and low molecular weight perfluoropolyether fully demonstrate that the compound system of phenyltriethoxysilane and fluoroalkylsiloxane oligomers, the compound filler of nano hollow SiO2 and nano monoclinic ZrO2, the blend system of PTFE emulsion and PFA emulsion, and the compound additive of low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether used in Example 5 have a significant synergistic effect in optimizing the dielectric properties and dimensional stability of high frequency ultrathin copper clad laminates, and can effectively improve the overall performance of high frequency ultrathin copper clad laminates.

[0053] Table 1 Performance test results of high-frequency ultrathin copper-clad laminate

[0054] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-frequency ultrathin copper-clad laminate, characterized by comprising the following steps: Step S1, Preparation of the base solution: Add deionized water to the reaction vessel, turn on low-speed stirring at 280-350 r / min, add propylene glycol polyether surfactant, and stir until the solution is completely clear and transparent to obtain the base solution; Step S2, Coupling agent activation: Add phenyltriethoxysilane and fluoroalkylsiloxane oligomer to the bottom liquid and stir at a low speed of 280-350 r / min for 20-30 min; Step S3, Filler dispersion: Transfer the solution prepared in step S2 to a high-speed stirrer, and add high-purity silicon micro powder, nano hollow SiO2 and nano monoclinic ZrO2 sequentially while stirring at a speed of 2400-2600 r / min. Disperse at high speed for 50-70 min to form a suspension. Step S4, Fluoropolymer Blending: Under low-speed stirring at 280-350 r / min, add PTFE emulsion and PFA emulsion to the suspension and stir for 30-40 min; then add low molecular weight perfluoropolyether and branched secondary alcohol polyoxyethylene ether, continue stirring for 35-45 min, and then let it stand at a constant temperature of 25-30℃ for 40-50 h to obtain the adhesive solution; Step S5, Casting and High-Temperature Sintering: Adjust the viscosity of the adhesive solution to 340-360 CPS with deionized water, and uniformly coat it onto a mirror stainless steel strip using a casting machine; dry with hot air at 68-72℃ for 23-28 min, sinter at 390-420℃ for 5-10 min, and peel off after natural cooling to obtain an ultra-thin uniform film with a thickness of 2.5±0.1 mil; Step S6, Vacuum hot pressing copper cladding: Cut and stack the film, cover both sides with copper foil, and place it between mirror steel plates; vacuum hot pressing, cool and depressurize to obtain high-frequency ultra-thin copper clad board.

2. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The propylene glycol polyether surfactant mentioned in step S1 is propylene glycol block polyether L-61; the mass ratio of deionized water to propylene glycol polyether surfactant mentioned in step S1 is 100:(3-5).

3. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The mass ratio of the base liquid, phenyltriethoxysilane, and fluoroalkylsiloxane oligomer in step S2 is (10³-10⁵):3:(1-2).

4. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The fluoroalkylsiloxane oligomer mentioned in step S2 is SiSiB® FF9020-1000 fluorinated silicone oil; the high-purity silicon powder mentioned in step S3 is 4N high-purity silicon powder with a particle size of 5000 mesh.

5. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The particle size of the nano-hollow SiO2 in step S3 is 300 nm; the nano-monoclinic ZrO2 is of type ZT-R80; the mass ratio of the solution prepared in step S2, high-purity silicon micro powder, nano-hollow SiO2, and nano-monoclinic ZrO2 in step S3 is (107-110):(100-110):8:

5.

6. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The PTFE emulsion mentioned in step S3 is of brand name JF-4DCA; the PFA emulsion is Pureflon. TM PFA FC680; the low molecular weight perfluoropolyether is model SL-90; ​​the branched secondary alcohol polyoxyethylene ether is branched secondary alcohol polyoxyethylene (5) ether S50.

7. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The mass ratio of the suspension, PTFE emulsion, PFA emulsion, low molecular weight perfluoropolyether, and branched secondary alcohol polyoxyethylene ether in step S4 is (220-233):242:104:(1-3):(5-7).

8. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The copper foil mentioned in step S6 is 0.5OZ ED copper foil.

9. The method for preparing high-frequency ultrathin copper-clad laminate according to claim 1, characterized in that, The parameters for vacuum hot pressing in step S6 are: temperature 360-380℃, pressure 460-500PSI, and holding time 100-120min.

10. A high-frequency ultrathin copper-clad laminate manufactured using the preparation method of the high-frequency ultrathin copper-clad laminate according to any one of claims 1-9.

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