A novel polymer resin for high-frequency and high-speed copper-clad laminates

Abstract

The application of polyacenaphthene resin in the field of high-frequency and high-speed copper-clad laminates is characterized by using acenaphthene as a raw material, heating it to a certain temperature, adding an initiator in a certain proportion, and reacting for a certain time to obtain polyacenaphthene resin. The polyacenaphthene resin is uniformly coated on glass fiber cloth and baked in an oven for a certain time to obtain a prepreg. The prepreg is coated with a metal foil, such as copper foil, and pressed in a vacuum hot press to obtain a copper-clad laminate. At a frequency of 5G, the dielectric constant of the single-layer resin copper-clad laminate is as low as 3.41.

Description

[0001] This application is a divisional application of the patent application filed on February 28, 2020, with application number 202010142038.8 and invention title "A Novel Polymer Resin for High-Frequency and High-Speed ​​Copper Clad Laminates". Technical Field

[0002] This invention relates to the field of high-frequency and high-speed copper-clad laminate technology, and in particular to polymer resin materials that function as adhesives, insulators, etc.

[0003] This invention relates to the application of polyacenaphthene resin with low dielectric constant and low dielectric loss in the field of metal-based copper-clad laminates (copper clad laminates). The polyacenaphthene resin includes acenaphthene homopolymer resin, copolymer resin, mixture of acenaphthene homopolymer resin and copolymer resin prepared from acenaphthene (CAS: 208-96-8), and mixture of polyacenaphthene resin with other resins. The preparation of copper clad laminates with polyacenaphthene resin is suitable for industrial production, filling a gap in this product category. Background Technology

[0004] With the rapid development of intelligent electronic products, represented by the electronics and information industries, digital circuits are gradually entering the stage of high-frequency signal transmission and high-speed information processing. In the future, the printed circuit board (PCB) industry will inevitably develop towards high frequency and high speed. Future electronic products will inevitably have high performance requirements such as small size, thinness, high frequency, and high speed, which also drives the development direction of copper clad laminate technology.

[0005] High-frequency, high-speed copper-clad laminates (CCLs) will become the focus of research and development in this industry, and the requirements for electrical insulation materials for CCLs have also entered a new stage. As CCLs develop towards higher functionality, higher performance, and higher reliability, higher requirements are placed on the comprehensive performance of electrical insulation materials, including heat resistance and dielectric properties, to adapt to the processing of multiple laminations and assemblies, as well as the development of future higher-frequency communication technologies. This requires the insulation materials used to have excellent dielectric properties to meet the needs of communication technologies in cutting-edge fields such as 5G.

[0006] Copper clad laminate (CCL) is a sheet material made by impregnating petroleum, wood pulp paper or fiberglass cloth with resin as reinforcing material, covering one or both sides with copper foil, and then hot-pressing it.

[0007] Copper clad laminates are mainly used to manufacture printed circuit boards (PCBs) and other devices, which are the basic components for manufacturing various types of electronic devices.

[0008] High-frequency and high-speed copper-clad laminates are copper-clad laminate products used in high-frequency and high-speed circuits that can meet their various electrical performance requirements.

[0009] The high-frequency, high-speed copper-clad laminate described in this invention can be used in multiple application areas such as 5G communication, automotive radar, and navigation systems. Figure 1 (Application range diagram of high frequency substrate).

[0010] According to the IPC2252 (Radio Frequency Circuit Design Guide) standard, microwave bands in the electromagnetic spectrum with a frequency range of 300MHz to 3000GHz are called high frequency. It is generally understood that frequencies with a range greater than 300MHz (wavelength less than 1m) are all called "high frequency".

[0011] In the printed circuit board industry, "high frequency" usually refers to the frequency range used to describe the interconnection of circuits and devices in distributed components. Generally, frequencies above 1 GHz are considered high frequency.

[0012] High-frequency copper-clad laminates (CCLs) are suitable for ultra-high frequency applications, possessing ultra-low loss characteristics (ultra-low signal transmission loss) and applicable to microwave / millimeter-wave fields. High-speed CCLs are used at high frequencies, featuring high signal transmission speeds (10-50Gbps), high characteristic impedance (Zo) accuracy, low signal dispersion (fewer bias circuits), and low loss. Their operating frequencies are between 1-5GHz, and they have even higher requirements for signal integrity.

[0013] As signal frequencies increase, it is often necessary to increase signal transmission speed to ensure the effectiveness and integrity of signal timing. Increased signal frequency inevitably leads to increased signal speed; that is, the evolution of high-frequency circuits has resulted in high-speed circuits. Overall, ultra-low loss characteristics and high transmission speed performance are both required in the field of high-frequency, high-speed copper-clad laminates.

[0014] The low loss performance of high-frequency, high-speed copper-clad laminates (CCLs) is typically reflected by their dielectric constant (Dk) or other relevant parameters; a lower Dk value generally indicates better performance. For the dielectric constant (Dk), the signal transmission rate is usually inversely proportional to the square root of the material's dielectric constant; a high dielectric constant can easily cause signal transmission delay. The smaller the dielectric constant of a high-frequency, high-speed CCL, the more stable the transmission. Furthermore, the Dk value also determines the theoretical signal transmission rate; a Dk value close to 1 corresponds to a transmission rate closer to the speed of light. Therefore, a lower Dk value is of significant and positive importance for the application of CCLs in high-frequency, high-speed circuits.

[0015] Low-frequency PCB substrates mostly use phenolic resin and epoxy resin, with glass fiber epoxy resin FR-4 being the most widely used product. However, in high-frequency, high-speed circuits, these traditional PCB substrates can cause signal distortion. Many factors affect the performance of copper-clad laminates, such as glass fiber modification and adjustments to the PCB dielectric layer layout. Among these, the selection of insulating materials for copper-clad laminates is a crucial aspect.

[0016] The electrical insulation resins that have been used in copper clad laminate applications include epoxy (EP) resins, phenolic resins, polyphenylene oxide (PPO) resins, cyanate ester (CE) resins, and polytetrafluoroethylene (PTFE) resins.

[0017] Epoxy (EP) resin has become the most widely used high-temperature thermosetting resin in high-performance composite materials in recent years due to its advantages such as good chemical resistance, good insulation, processability, and low cost. It plays an important role in various applications in the electronics field.

[0018] Polyphenylene oxide (PPO) resin has excellent dielectric properties, low moisture absorption, good adhesion to copper foil, heat resistance, flame retardancy and dimensional stability, and has become one of the important materials in the printed circuit board industry with low dielectric properties and high heat resistance.

[0019] Cyanate ester (CE) resins have received significant attention in recent years due to their excellent dielectric properties, outstanding heat resistance, and superior mechanical properties.

[0020] The aforementioned epoxy (EP) resins, phenolic resins, polyphenylene oxide (PPO) resins, and cyanate ester (CE) resins are widely used in the copper clad laminate (CCL) industry. However, the relatively high proportions of oxygen and nitrogen in these materials have two main impacts. Their high water absorption and polarity result in relatively high dielectric constants and dielectric losses, which cannot meet the requirements of high-frequency, high-speed CCLs.

[0021] Polytetrafluoroethylene (PTFE) resin has excellent dielectric properties and low moisture absorption, making it well-suited for applications in the copper clad laminate (CCL) industry. However, due to the inherent physical properties of the material, its poor processing performance and low yield limit its widespread use in CCLs.

[0022] Currently, commercially available high-frequency and high-speed copper-clad laminates generally include PTFE / ceramic filler substrates, hydrocarbon thermosetting materials / ceramic materials substrates, thermosetting engineering plastics / ceramic filler substrates, and LCP substrates.

[0023] Table 1. Information on known commercially available insulating resins

[0024]

[0025] The wide variety of resins makes selecting the right one for high-frequency, high-speed copper-clad laminates (CCLs) challenging. Therefore, it remains necessary to develop different types of insulating resins with lower dielectric constants to meet the demands of high-frequency, high-speed CCL applications.

[0026] This invention, based on years of research, has discovered that polyacenaphthene resin prepared using acenaphthene as a monomer has a low dielectric constant and low dielectric loss, meeting the requirements of high-frequency, high-speed copper-clad laminates. While previous studies have yielded the following findings, there have been no reports on the application of polyacenaphthene resin in the field of high-frequency, high-speed copper-clad laminates.

[0027] (I) Preparation methods of acenaphthene and polyacenaphthene resin

[0028] J. Schmelzer and J. Springe's paper "Production and properties of polyacenaphthylene—VI. Influence of polymerization conditions on chain structure" describes the preparation method of acenaphthylene polymer, but does not describe the application of acenaphthylene polymer resin.

[0029] The 1951 paper "Acenaphthylene: Its Polymers and Copolymers" in J. APPL. CHEM and the patent "Polymers and copolymers of acenaphthylene" (United States Patent: 2445181) reported methods for preparing acenaphthylene and acenaphthylene polymers and copolymers, but did not describe the application of polyacenaphthylene resin in copper-clad laminates.

[0030] The paper "Successful Experiment of Preparing Acenamethanone from Acenamethanone," published in the May 1972 issue of *Liaoning Chemical Industry*, described the preparation method of acenamethanone and its use in preparing electrical insulating materials, achieving a level comparable to epoxy resin insulating materials. However, it did not explicitly mention the application of polyacenamethanone resin in copper-clad laminates.

[0031] In 2018, Gu Zhenggui, Cao Xiaoyan, and Ling Hongyu of Nanjing Normal University published an invention patent entitled "Apparatus and Method for Extracting Acenaphen and Acenaphenene from LCO Bicyclic Aromatic Hydrocarbons" (Patent No.: CN201811485681.X), which reported a process for preparing acenaphthene by distillation extraction. However, it did not explicitly use polyacenaphthene resin in copper-clad laminates.

[0032] In 2005, Michitaka Ota and Genki Takeuchi of Nippon Steel Chemical Co., Ltd. described a method for manufacturing polycyclic aromatic vinyl compounds (PACs) in their patent "Method for Manufacturing Polycyclic Aromatic Vinyl Compounds" (Patent No.: CN200510008106.7). The method involved adding an adductor such as halogen, hydrogen halide, or water to the vinyl group of a PAC such as divinylnaphthalene, divinylbiphenyl, or acenaphthene to form a corresponding PAC derivative. The PAC derivative was then purified by recrystallization, adsorption, or a chemical reaction. Finally, the adductor was removed from the PAC derivative to obtain a high-purity PAC. However, the use of polyacenaphthene resin in copper-clad laminates was not explicitly stated.

[0033] In 1999, Jiang Qun of China University of Mining and Technology reported the dehydrogenation reactions of various methylene-containing aromatic hydrocarbons in the presence of N-bromosuccinimide (NBS) in his paper "Study on Dehydrogenation Reactions of Methylene-Containing Aromatic Hydrocarbons". This method can be used to dehydrogenate acenaphthene to produce acenaphthene. However, the application of polyacenaphthene resin in copper-clad laminates was not explicitly stated.

[0034] (II) Applications of Acenamethanone in the field of photochemistry

[0035] The invention patent "Acenaphthylene-modified phenolic resin and epoxy resin composition" (Publication No.: WO2003104295 A1) by Masashi Kaji, Kazuhiko Nakahara, and Kiyokazu Yonekura reports acenaphthylene-modified phenolic resin. Vinyl-modified phenolic resin can be used as an epoxy resin intermediate and curing agent. Epoxy resins possess excellent heat resistance, flame retardancy, and low moisture absorption, making them suitable for sealing electrical and electronic components and as materials for circuit boards, etc. This patent pertains to the invention of acenaphthylene-modified phenolic resin, not the use of polyacenaphthylene resin in copper-clad laminates.

[0036] In 2001, Yin Yiqing, Fang Yu, Hu Daodao, and Gao Gailing from Huizhou University in Guangdong and Shaanxi Normal University reported in the *Acta Physico-Chimica Sinica* the synthesis of N-vinylcarbazole (NVCz)-labeled methacrylic acid (MAA)-acenaphthene copolymers (PMAA-ACE / NVCz) of acenaphthene (ACE). They studied the fluorescence behavior of each copolymer in dilute aqueous solutions and the effects of pH and surfactants on the fluorescence properties of the copolymers. No specific application of polyacenaphthene resin in copper-clad laminates was reported.

[0037] In 2012, Xie Xingen of Nanjing University of Science and Technology described the preparation of a conductive polymer, polyacenaphthene (PAcN), via electrochemical anodic oxidation in his master's thesis, "Electrochemical Homopolymerization / Copolymerization of Some Fused-Ring Aromatic Compounds." The structure and morphology of the polymer were analyzed by UV, IR, NMR, and SEM, and thermogravimetric and electrochemical analyses were also performed. The PAcN film exhibited good redox properties and high thermal stability, with a conductivity of 0.43 S cm⁻¹. -1 Fluorescence spectroscopy indicates that PAcN is a good green luminescent material. There is no explicit evidence of the use of polyacenaphthene resin in copper-clad laminates.

[0038] In 2017, Ge Tiejun, Wang Jia, Wang Chengcheng, Xu Zhihua, and Tang Kaihong of Shenyang University of Chemical Technology described a polyacenaphthene-type copolymer allyl phenolic reactive diluent resin and its preparation method in their patent "A Chalena-type Polyphenyl Copolyallylic Phenolic Reactive Diluent Resin and Its Preparation Method" (Patent No.: CN201610809908.6). The resin incorporates multiple benzene ring groups, giving it high-temperature resistance and thermal oxidation stability. However, the patent does not explicitly mention the application of polyacenaphthene resin in copper-clad laminates.

[0039] In 2010, Shin-Etsu Chemical Co., Ltd.'s invention patent, "Method for Forming Photoresist Patterns and Method for Manufacturing Photomasks" (application / patent number: CN200910140186.X), by Takanobu Takeda, Satoshi Watanabe, Tamotsu Watanabe, Keijun Tanaka, Keiichi Masunaga, and Ryuji Kobutashi, described a method for forming photoresist patterns. This method uses a photoresist composition made of a polymer of styrene units and indene or acenaphthene units as the matrix polymer of a chemically amplified photoresist composition, providing a method for forming photoresist patterns with pattern rules of 65 nanometers or less. The use of polyacenaphthene resin in copper-clad laminates was not explicitly stated.

[0040] (III) Applications in other fields

[0041] In his 2005 master's thesis at East China University of Science and Technology, titled "Synthesis, Polymerization, and Properties of Chromium Carbonyl Complexes Containing Vinyl Polycyclic Aromatic Hydrocarbons," Luo Xili described the synthesis of π-organo-aromatic carbonyl chromium complexes with metal-aromatic conjugated large π bonds by coordinating the electron-withdrawing electron-withdrawing tricarbonyl chromium (Cr(CO)<,3>) with the aromatic compounds acenaphthene and N-vinylcarbazole. The complexes were then subjected to free radical homopolymerization and copolymerization to obtain metal-aromatic coordination polymers. Several new phenomena were discovered, including improvements in some properties of organometallic polymers (e.g., photophysical properties, thermal stability) and the emergence of new properties (e.g., charge transfer complexes, excitocomplexes) resulting from the coordination of the metal group. The application of polyacenaphthene resin in copper-clad laminates was not explicitly described.

[0042] In his 2006 doctoral dissertation at Lanzhou University, Chen Yong described the synthesis of acenaphthene-labeled poly(N,N-diethylacrylamide) (PDEA), a copolymer of N,N-diethylacrylamide and N-hydroxymethylacrylamide (P(DEA-co-NHMAA)), and a copolymer of N,N-diethylacrylamide and styrene (P(DEA-co-St)). Using photophysical methods such as fluorescence intensity, fluorescence quenching, and fluorescence anisotropy techniques, he investigated the changes in the hydrophilic / hydrophobic structure of the PDEA polymer chain in extremely dilute aqueous solutions, as well as the changes in solvent properties caused by the addition of inorganic salts, urea, and methanol. He systematically studied the conformational changes of the thermosensitive polymer PDEA and the mechanisms of hydrogen bonding, electrostatic interactions, hydrophobic association, and solvation of the aqueous layer that led to these conformational changes. However, he did not explicitly use polyacenaphthene resin in copper-clad laminates.

[0043] In 2007, the Shanghai Applied Technology Achievements report, "Synthesis and Photoelectric Properties of η6-Carbazole-Containing Polymer Metal Complexes," described the synthesis of a series of organometallic complexes using N-vinylcarbazole, acenaphthene, and their derivatives as ligands to coordinate with metal groups. The complexes were then characterized by spectroscopic analysis and single-crystal X-ray diffraction. A series of coordination polymer polarized orientation films were prepared under an electric field and compared with their solutions. By studying the relationship between intramolecular and intermolecular charge transfer and aggregated structure, the report provided experimental and theoretical basis for the development of novel organometallic optoelectronic functional materials. However, the application of polyacenaphthene resin in copper-clad laminates was not explicitly documented.

[0044] (iv) Applications in the field of dielectric base materials for laminated circuit boards or printed circuit boards

[0045] In 2003, Honeywell International Inc. filed a patent application entitled "Organic Compositions for Low Dielectric Constant Materials" (Publication No.: CN1643669, Patent No.: CN03805938.X), describing a composition comprising unfunctionalized polyacenaphthene homopolymers, functionalized polyacenaphthene homopolymers, polyacenaphthene copolymers, etc. The composition in this invention can be used as a dielectric matrix material for microchips, multi-chip modules, laminated circuit boards, or printed circuit boards. The patent differs from this invention in three main aspects: 1. Different raw materials: The Honeywell patent involves polyacenaphthene polymer, whose raw material is industrial-grade acenaphthene (pure acenaphthene), which does not involve acenaphthene at all. This invention uses acenaphthene as the material in its polyacenaphthene polymer. The two raw materials are different compounds with significant differences in structure and performance. Furthermore, the Honeywell patent does not suggest or guide technicians to consider using acenaphthene; 2. Different usage methods: In the Honeywell patent, the polyacenaphthene polymer is used as a pore-forming agent, not as the copper-clad laminate. The insulating materials and / or adhesives of the present invention are used as the main resin of the insulating materials and / or adhesives of copper clad laminates; 3. Different uses: in the Honeywell patent, the polyacenaphthene polymer is a pore-forming agent, and after decomposition and volatilization, it forms cavities. The gas in the cavities causes the organic composition to obtain suitable properties. In the present invention, the polyacenaphthene polymer is used as the main resin. The chemical composition of the polyacenaphthene polymer does not contain heteroatoms such as oxygen, sulfur, and nitrogen. The polyacenaphthene polymer itself has the properties of low water absorption and low polarity, as well as low dielectric constant.

[0046] The structures of the raw materials acenaphthene and acenaphthene are as follows:

[0047]

[0048] Technical materials report the use of resins in the field of copper clad laminates, but do not disclose the specific resin monomers (resin types). In the promotion of Panasonic's R-5575 copper clad laminate, Panasonic describes that "through our company's unique resin design technology and low-roughness copper foil bonding technology, we have achieved a balance between excellent low transmission loss and processability." Panasonic does not specify the composition and monomer structure of the "unique resin," and their research differs from that of this invention.

[0049] As can be seen from the description of the prior art above, selecting a resin suitable for high-frequency, high-speed copper-clad laminates is not easy due to the significant differences in resin structure and properties. Therefore, it remains necessary to develop different types of insulating resin products with lower dielectric constants to meet the needs of high-frequency, high-speed copper-clad laminate applications. Summary of the Invention

[0050] To meet the demand for low dielectric constant insulating materials in the field of high-frequency and high-speed copper-clad laminates (CCLs), this invention provides the application of polyacenaphthene resin in the CCL field and related products. This invention relates to polyacenaphthene resin with low dielectric constant and low dielectric loss, which can be used as a polymer resin in the preparation of high-frequency and high-speed CCLs. The polyacenaphthene resin includes homopolymer resins, copolymer resins, mixtures of homopolymer and copolymer resins of acenaphthene (CAS: 208-96-8) and mixtures of polyacenaphthene resin with other resins. The preparation of CCLs using polyacenaphthene resin is suitable for industrial production, filling a gap in the industrial production of this product.

[0051] To achieve the above objectives, the present invention employs the following technical solution:

[0052] One embodiment of the present invention is a high-frequency, high-speed copper-clad laminate, wherein polyacenaphthene resin is used as the polymer resin. The resin is prepared from acenaphthene monomer. Using acenaphthene as a raw material, heating and adding an initiator, a reaction is carried out to obtain polyacenaphthene resin. The polyacenaphthene resin is uniformly coated onto a glass fiber material, such as glass fiber cloth, and baked in an oven to obtain a prepreg. Prepreg sheets with smooth surfaces and uniform coating are cut to a certain size, stacked neatly, and copper foil is attached to the top and bottom. The sheets are then pressed in a vacuum hot press to obtain the copper-clad laminate. At a frequency of 5G, the dielectric constant of the single-layer resin copper-clad laminate is as low as 3.41.

[0053] Structural formula of acenaphthene monomer:

[0054]

[0055] The structural formula of polyacenaphthene resin:

[0056]

[0057] n is the number of repeating units.

[0058] Another embodiment of the present invention includes the use of polyacenaphthene resin in high-frequency, high-speed copper-clad laminates.

[0059] Another embodiment of the present invention includes a method for preparing copper-clad laminate using the polyacenaphthene resin, specifically comprising the following steps:

[0060] 1. Add acenaphthene to a reaction vessel, heat to the specified temperature, then add an initiator in a certain proportion, and react for a certain time to obtain polyacenaphthene resin;

[0061] 2. Polyacenaphthene resin is uniformly coated onto fiberglass cloth and baked in an oven to obtain a semi-cured sheet;

[0062] 3. Take a flat and evenly coated semi-cured sheet, attach copper foil to the top and bottom, and press it in a vacuum hot press to obtain a copper-clad laminate.

[0063] In the method for preparing acenaphthene resin, the heating temperature range is 90℃~160℃, preferably 105℃~140℃, and most preferably 120℃;

[0064] The initiator can be a peroxide, preferably m-chloroperoxybenzoic acid, benzoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, 2,4-dichloroperoxybenzoic acid, and most preferably di-tert-butyl peroxide.

[0065] The mass ratio of the acenaphthene monomer to the initiator is 2000:1 to 50:1, preferably 200:1;

[0066] The reaction time is 0.5h to 4.0h, preferably 1.5h.

[0067] There are no particular restrictions on the preparation methods of the prepreg and the final copper-clad laminate; conventional methods known in the art can be used.

[0068] When making prepreg, the heating time can range from 0.1h to 1.0h, and the heating temperature can range from 120℃ to 180℃.

[0069] The polyacenaphthene resin is characterized in that the polymer resin prepared from acenaphthene includes acenaphthene homopolymer resin, copolymer resin, a mixture of acenaphthene homopolymer resin and copolymer resin, and a mixture of polyacenaphthene resin and other resins.

[0070] The polyacenaphthene resin is characterized in that the polymer resin prepared from acenaphthene raw material includes acenaphthene homopolymer resin, copolymer resin, a mixture of acenaphthene homopolymer resin and copolymer resin, and a mixture of polyacenaphthene resin and other resins, wherein the content of polyacenaphthene resin is 5.0% to 95.0%, preferably 80.0% to 95.0%.

[0071] The fiberglass cloth is characterized in that it can be used or not used; the prepreg is covered with metal foil, characterized in that the prepreg is used in one or more layers stacked together, with metal foil covering the top and bottom surfaces of the prepreg or between the layers. The stacked prepreg consists of 2-30 layers, preferably 5-26 layers.

[0072] The copper-clad laminate structure and features described in this invention are also suitable for other types of substrates in the field of high-frequency and high-speed circuit boards. For example, the metal base foil covering the substrate includes gold foil, copper foil, silver foil, and aluminum foil, which can be used alone or in combination, with copper foil being the most preferred.

[0073] Compared with the prior art, the beneficial effects of the present invention are:

[0074] 1) The present invention redesigns the resin used in copper clad laminates. Compared with the existing technology, the newly selected polyacenaphthene resin is a hydrocarbon polymer resin that does not contain oxygen, sulfur, nitrogen and other elements. The resin has low water absorption and water content, resulting in a low dielectric constant of the copper clad laminate.

[0075] 2) The present invention redesigns the resin used in copper clad laminates. Compared with the existing technology, the newly selected polyacenaphthene resin is a hydrocarbon polymer resin that does not contain polar groups such as oxygen, sulfur, and nitrogen elements. The overall polarity of the resin is low, resulting in a low dielectric constant of the copper clad laminate.

[0076] 3) The present invention redesigns the resin used in copper clad laminates. Compared with the existing technology, the newly selected polyacenaphthene resin is a hydrocarbon polymer resin with a low softening point and good processing performance, which is suitable for the processing and manufacturing of copper clad laminates.

[0077] 4) This invention uses polyacenaphthene resin to prepare copper-clad laminates, resulting in high yield and significant cost reduction;

[0078] 5) This invention is a new copper-clad laminate system that fills a gap in the product market.

[0079] In summary, the following points can be observed: 1. Since the existing technology does not teach the use of acenaphthene to prepare acenaphthene homopolymer resin, copolymer resin, mixtures of acenaphthene homopolymer resin and copolymer resin, or mixtures of polyacenaphthene resin with other resins for application in the copper clad laminate (CCL) field, and the application of polyacenaphthene resin in the CCL field is not a necessary condition, it is not obvious to those skilled in the art to use acenaphthene to prepare acenaphthene homopolymer resin, copolymer resin, mixtures of acenaphthene homopolymer resin and copolymer resin, or mixtures of polyacenaphthene resin with other resins in the CCL field; 2. The existing technology does not teach the application of acenaphthene polymer resin in CCL as described in this invention, achieving a dielectric constant as low as 3.41 for a single-layer resin CCL at 5G frequencies, so such a technical solution is also not obvious; 3. When using this invention to prepare CCL, the raw material cost is low, the preparation process is simple, and the yield is high, meeting the needs of industrial production in terms of both economy and environmental protection, representing a significant improvement over the existing technology. Attached image description:

[0080] Figure 1 Application range diagram of high frequency substrates

[0081] The attached diagram shows that high-frequency substrates have wide applications in fields such as 5G communication, automotive radar, and navigation systems.

[0082] Figure 2 : Structure diagram of polyacenaphthene resin copper clad laminate

[0083] The reference numerals in the attached diagram have the following meanings: 1. Copper foil; 2. Polyacenaphthene resin; 3. Fiberglass cloth. Detailed Implementation

[0084] The raw materials and reagents used in the embodiments of the present invention are as follows:

[0085]

[0086] The acenaphthene raw material used in this patent is commercially available, for example, from TCI (Shanghai) Chemical Industry Development Co., Ltd. Instrumentation and testing characteristics:

[0087] Dielectric properties: Tested using an Agilent N5230A vector network analyzer (SPDR). At 5GHz... Z The copper-clad laminate prepared by measuring capacitance and voltage was used to calculate the dielectric constant Dk value based on the layer thickness.

[0088] Example 1

[0089] Preparation of polyacenaphthene resin copper clad laminate 1

[0090] 1. Add 50.16 g of acenaphthene to a 200 mL reactor equipped with a stirrer, heat to 120 °C, and stir for 20 min until the acenaphthene is completely melted into a yellow transparent liquid. Add 0.25 g of di-tert-butyl peroxide (0.5% of the amount of acenaphthene added), and react for 1.5 h. The reaction system is a reddish-brown viscous liquid. Take a sample for thin-layer chromatography analysis. After all the acenaphthene is consumed, polyacenaphthene resin is obtained. Immediately proceed to the next step.

[0091] 2. Preheat the coating device at 140℃ for 0.5h, load the glass fiber cloth (20cm×20cm), uniformly coat a 1.6mm thick layer of the newly prepared polyacenaphthene resin, and then bake it in an oven at 140℃ for 0.5h to obtain a reddish-brown semi-cured sheet. Immediately proceed to the next step.

[0092] 3. Take the newly prepared semi-cured sheet with a smooth surface and uniform coating, attach copper foil to the top and bottom, place it in a vacuum hot press preheated to 140°C, raise it to 190°C within 5 minutes and hold it for 90 minutes; raise it to 1.0 MPa within 1 minute and hold it for 90 minutes to obtain a 1.6 mm thick polyacenaphthene resin copper clad laminate 1.

[0093] At 5G frequency, the dielectric constant of the polyacenaphthene resin copper clad laminate 1 was measured to be 3.41.

[0094] Example 2

[0095] Preparation of polyacenaphthene resin copper clad laminate 2

[0096] 1. Add acenaphthene (49.16g) to a 200mL reactor equipped with a stirrer, heat to 110℃, and stir for 20min until all acenaphthene is melted into a yellow transparent liquid. Add m-chloroperoxybenzoic acid (0.5g, 1.0% of the acenaphthene feed amount), and react for 1.0h. The reaction system is a reddish-brown viscous liquid. Take a sample for thin-layer chromatography analysis. After all acenaphthene is consumed, polyacenaphthene resin is obtained. Immediately proceed to the next step.

[0097] 2. Preheat the coating device at 140℃ for 0.5h, load the glass fiber cloth (20cm×20cm), uniformly coat a 1.6mm thick layer of the newly prepared polyacenaphthene resin, and then bake it in an oven at 140℃ for 0.5h to obtain a reddish-brown semi-cured sheet. Immediately proceed to the next step.

[0098] 3. Take the newly prepared semi-cured sheet with a smooth surface and uniform coating, attach copper foil to the top and bottom, place it in a vacuum hot press preheated to 160°C, raise it to 190°C within 5 minutes and hold it for 90 minutes; raise it to 1.0 MPa within 1 minute and hold it for 90 minutes to obtain a 1.6 mm thick polyacenaphthene resin copper clad laminate 2.

[0099] At 5G frequency, the dielectric constant of the polyacenaphthene resin copper clad laminate 2 was measured to be 3.43.

[0100] Example 3

[0101] Preparation of glass fiber-free polyacenaphthene resin copper clad laminate 3

[0102] 1. Add 50.08 g of acenaphthene to a 200 mL reactor equipped with a stirrer, heat to 120 °C, and stir for 20 min until the acenaphthene is completely melted into a yellow transparent liquid. Add 0.25 g of di-tert-butyl peroxide (0.5% of the amount of acenaphthene added), and react for 1.5 h. The reaction system is a reddish-brown viscous liquid. Take a sample for thin-layer chromatography analysis. After all the acenaphthene is consumed, polyacenaphthene resin is obtained. Immediately proceed to the next step.

[0103] 2. Preheat the coating device at 140°C for 0.5 hours, uniformly coat a 1.6 mm thick layer of the newly prepared polyacenaphthene resin, and then bake it in an oven at 140°C for 0.5 hours to obtain a reddish-brown semi-cured sheet. Immediately proceed to the next step.

[0104] 3. Take the newly prepared semi-cured sheet with a smooth surface and uniform coating, attach copper foil to the top and bottom, place it in a vacuum hot press preheated to 140°C, raise it to 190°C within 5 minutes and hold it for 90 minutes; raise it to 1.0 MPa within 1 minute and hold it for 90 minutes to obtain a 1.6 mm thick polyacenaphthene resin copper clad laminate 3.

[0105] At 5G frequency, the dielectric constant of the polyacenaphthene resin copper clad laminate 3 was measured to be 3.41.

[0106] Example 4

[0107] Preparation of mixed resin copper clad laminate 4

[0108] 1. Add 50.12 g of acenaphthene to a 200 mL reactor equipped with a stirrer, heat to 120 °C, and stir for 20 min until the acenaphthene is completely melted into a yellow transparent liquid. Add 0.25 g of di-tert-butyl peroxide (0.5% of the acenaphthene feed amount), and react for 1.5 h. The reaction system is a reddish-brown viscous liquid. Take a sample for thin-layer chromatography analysis. After all the acenaphthene is consumed, polyacenaphthene resin is obtained. Add 50 mL of methyl ethyl ketone (MEK) and stir for 10 min. Immediately proceed to the next step.

[0109] 2. Weigh out 50.05g of polyphenylene ether and add it to a 200mL stirred reactor containing 50mL of methyl ethyl ketone (MEK). Stir for 0.5h to dissolve the polyphenylene ether. Add the methyl ethyl ketone solution of polyacenaphthene resin and stir to mix evenly to prepare a light yellow transparent adhesive with a solid content of 50%.

[0110] 3. Impregnate fiberglass cloth (20cm×20cm) with resin, then bake in an oven at 150℃ for 0.5h to obtain a reddish-brown semi-cured sheet;

[0111] 4. Take 8 newly prepared semi-cured sheets with smooth surfaces and uniform coating, stack them neatly, attach copper foil on the top and bottom, place them in a vacuum hot press preheated to 140°C, raise the temperature to 190°C within 5 minutes and hold for 90 minutes; raise the pressure to 1.0 MPa within 1 minute and hold for 90 minutes to obtain a 1.6 mm thick polyacenaphthene mixed polyphenylene ether resin copper clad laminate 4.

[0112] At 5G frequency, the dielectric constant of the copper clad laminate 4 made of polyacenaphthene mixed with polyphenylene ether resin was determined to be 3.52.

[0113] Comparative Example 1

[0114] Preparation of polyphenylene ether copper clad laminate 5

[0115] 1. Weigh out 50.08g of polyphenylene ether and add it to a 200mL stirred reactor containing 50mL of methyl ethyl ketone. Stir for 0.5h to dissolve the polyphenylene ether and prepare a light yellow transparent adhesive solution with a solid content of 50%.

[0116] 2. Impregnate fiberglass cloth (20cm×20cm) with resin, then bake in an oven at 150℃ for 0.5h to obtain a yellow semi-cured sheet;

[0117] 3. Take 8 newly prepared semi-cured sheets with smooth surfaces and uniform coating, stack them neatly, attach copper foil on the top and bottom, place them in a vacuum hot press preheated to 140°C, raise the temperature to 190°C within 5 minutes and hold for 90 minutes; raise the pressure to 1.0 MPa within 1 minute and hold for 90 minutes to obtain a 1.6 mm thick polyphenylene ether resin copper-clad laminate 5.

[0118] At 5G frequency, the dielectric constant of the polyphenylene ether resin copper clad laminate 5 was measured to be 3.58.

[0119] Through the embodiments and comparative examples of the present invention, it can be seen that the polyacenaphthene resin of the present invention can significantly reduce the dielectric constant of copper-clad laminates, even when mixed with other types of resins, it can still significantly reduce the dielectric constant. Therefore, the technical solution of the present invention can manufacture copper-clad laminates with low dielectric loss and related electronic devices, making them suitable for application in the field of high-frequency and high-speed circuits. In particular, the technical solution of the present invention is suitable for application in 5G-related technical fields, including 5G base stations, 5G mobile electronic devices, 5G automotive equipment, and other electronic devices. Furthermore, the technical solution of the present invention is also applicable to other high-frequency and high-speed circuit-related fields such as radar, navigation, and intelligent driving.

[0120] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention. Moreover, in addition to the above-described embodiments, the present invention also includes combinations of the technical features in the above embodiments, because those skilled in the art, after reading the present invention, can directly and without doubt determine that the technical features mentioned in the present invention, after appropriate combination, can still solve the relevant technical problems.

Claims

1. A printed circuit board, which is fabricated using a high-frequency, high-speed copper-clad laminate as a substrate, wherein the copper-clad laminate comprises a substrate, a polymer resin, and copper foil, characterized in that... The polymer resin is polyacenaphthene resin, which is a homopolymer of acenaphthene, a copolymer of acenaphthene, or a mixture of homopolymer of acenaphthene and copolymer of acenaphthene. The polyacenaphthene resin is a hydrocarbon polymer resin and does not contain oxygen, sulfur, or nitrogen.

2. The printed circuit board as described in claim 1, characterized in that... The substrate is made of glass fiber.

3. The printed circuit board as described in claim 2, characterized in that... The substrate is fiberglass cloth.

4. A high-frequency, high-speed copper-clad laminate, wherein the copper-clad laminate comprises a substrate, a polymer resin, and copper foil, characterized in that... The polymer resin is polyacenaphthene resin; the polyacenaphthene resin is acenaphthene homopolymer resin, acenaphthene copolymer resin, or a mixture of acenaphthene homopolymer resin and acenaphthene copolymer resin, and the polyacenaphthene resin is a hydrocarbon polymer resin that does not contain oxygen, sulfur, or nitrogen elements.

5. The copper-clad laminate as described in claim 4, characterized in that... The substrate is made of glass fiber.

6. The copper-clad laminate as described in claim 5, characterized in that... The substrate is fiberglass cloth.

7. An electronic device comprising a printed circuit board as described in any one of claims 1-3.

8. The electronic device as described in claim 7 is a communication electronic device used in the 5G field.

9. The electronic device as claimed in claim 8, wherein the device is selected from 5G base station equipment, 5G mobile equipment, and 5G vehicle-mounted equipment.

10. The use of polyacenaphthene resin as a polymer resin in high-frequency, high-speed copper-clad laminates, wherein the polyacenaphthene resin is a homopolymer resin of acenaphthene, a copolymer resin of acenaphthene, or a mixture of homopolymer resin of acenaphthene and copolymer resin of acenaphthene, and the polyacenaphthene resin is a hydrocarbon polymer resin that does not contain oxygen, sulfur, or nitrogen.

11. The use as described in claim 10, wherein the high-frequency, high-speed copper-clad laminate is as described in any one of claims 4-6.

12. The use as described in claim 10, wherein the copper-clad laminate is used to fabricate a substrate for a high-frequency, high-speed circuit, the high-frequency, high-speed circuit being used in 5G communication technology.

13. The use as claimed in claim 10, wherein the polyacenaphthene resin is used as an adhesive and / or an insulating material.

14. A method for preparing a high-frequency, high-speed copper-clad laminate, wherein the copper-clad laminate is prepared by applying polyacenaphthene resin to a substrate and then adhering copper foil; characterized in that: (1) The preparation steps of the polyacenaphthene resin include using acenaphthene monomer as raw material, heating, adding initiator, and holding the reaction to obtain polyacenaphthene resin. The polyacenaphthene resin is a hydrocarbon polymer resin and does not contain oxygen, sulfur, or nitrogen elements. (2) The application step includes uniformly coating polyacenaphthene resin onto glass fiber material, baking it in an oven to obtain a semi-cured sheet, and then cutting out semi-cured sheets with flat surfaces and uniform coating according to a predetermined size and stacking them neatly. (3) The copper foil adhesion step includes attaching copper foil to the upper and lower surfaces of the neatly stacked prepreg and pressing it in a vacuum hot press to obtain the copper-clad laminate.

15. The preparation method according to claim 14, wherein the number of layers of the prepreg in step (2) is 2-30.

16. The preparation method according to claim 14, wherein the heating temperature is 90°C to 160°C.

17. The preparation method according to claim 14, wherein the initiator is a peroxide selected from one of m-chloroperoxybenzoic acid, benzoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, and 2,4-dichloroperoxybenzoyl.

18. The preparation method according to claim 14, wherein the mass ratio of acenaphthene monomer to initiator is 2000:1 to 50:

1.

19. A substrate for high-frequency, high-speed circuits, the substrate comprising a substrate, a polymer resin, and a metal foil, characterized in that... The polymer resin is polyacenaphthene resin, which is a homopolymer resin, copolymer resin, or a mixture of homopolymer resin and copolymer resin. The polyacenaphthene resin is a hydrocarbon polymer resin and does not contain oxygen, sulfur, or nitrogen. The metal foil includes gold foil, copper foil, silver foil, and aluminum foil, which can be used alone or in combination.

20. Use of the substrate as described in claim 19 in high-frequency, high-speed circuits.

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