High-frequency copper foil substrate and composite material used thereby

Abstract

The invention discloses a high-frequency copper foil substrate with an operating frequency of more than 1GHz, which has a dielectric constant Dk of less than 3.2 and a loss factor Df of less than 0.005 as well as high glass transition temperature, high thermostability and low moisture-absorption characteristic. The high-frequency copper foil substrate contains a special composite material and is prepared by impregnating a reinforcing material with blended resin mixture. The resin mixture of the composite material is prepared by blending the following materials: (a) high molecular weight polybutadiene resin; (b) low molecular weight polybutadiene resin; (c) modified polyphenyl ether thermosetting resin; (d) inorganic powder; (e) flame retardant; (f) cross-linking agent; (g) binding aid; and (h) hardening initiator. In the invention, the drawback of low processability of pure polybutadiene with low viscosity and the drawback of need of adding plasticizer of polyphenyl ether resin (PPE) with low solubility; particularly, the non-viscous pre-impregnated sheets made by the composite material can be processed into copper foil substrates automatically.

Description

technical field [0001] The invention is a high-frequency copper foil substrate, especially a high-frequency copper foil substrate with a dielectric constant (Dk)<3.2 and a loss factor (Df)<0.005 and the composite material used therein. Background technique [0002] With the rapid growth of the 3C industry (electronics, computers and communications), the use specifications of printed circuit boards (PCBs) have been correspondingly increased to use frequency ranges up to 1GHZ, and it is necessary to use low dielectric constant (Dk<3.2) and low High-frequency substrate material with loss factor (Df<0.005) characteristics. [0003] In the past, high-frequency substrate materials were made of polybutadiene resin as the main material, and were produced by traditional impregnation and high-temperature vacuum lamination processes of printed circuit boards (PCBs). However, polybutadiene is highly viscous, and the resulting prepreg cannot be continuously produced by tradi...

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Problems solved by technology

In addition to the need for high-temperature hardening (that is, hot-pressing temperature > 250°C), this patent has not yet solved the problem that polybutadiene is highly viscous and makes it difficult to continuously automate the production of circuit substrates.

[0006] In order to solve the problem of high viscosity of polybutadiene, U.S. Patent 6,071,836 discloses a circuit carrier composite material with a large amount of filler (filler), and the prepreg made has almost no tack (tack-free), so it allows Traditional automated layup processing is used; however, because the filler ratio of the composite material is above 50wt%, even up to 70wt%, there is still the disadvantage that the fabric reinforcement material (fabric reinforcement) is not easy to be impregnated uniformly in the impregnation process , and the rigidity of the obtained circuit carrier is too large, and the drill pin wears too much during the drilling process, making it difficult to process

[0007] In the field of plastics, polyphenylene ether resin is a high temperature resistant thermoplastic engineering plastic with excellent physical properties, such as low dielectric constant, low loss factor, high glass transition temperature, low water absorption, high heat resistance and high Electrical insulation, but poor melt fluidity, difficult processing, in order to improve processing performance, it needs to be modified

[0008] However, when the number average molecular weight (Mn) of polyphenylene ether resin is higher than 10,000, the solubility in organic solvents is low and the melt viscosity is high, which is not suitable for application on circuit boards

When the number average molecular weight of the polyphenylene ether resin is lower than 10,000, the physical properties of the polyphenylene ether resin will decrease, including the dielectric constant, loss factor, glass transition temperature and viscosity, which will not meet the requirements of high frequency and low dielectric strength. The need for constant, low dissipation factor circuit substrates

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