Analysis of High-Frequency, High-Speed PCB Substrates: Performance Differences Between Halogenated and Halogen-Free Flame Retardants in Terms of Dielectric Loss and Reliability

In the era of high-frequency, high-speed communications, 5G/6G base stations and high-performance servers place stringent demands on the signal integrity of printed circuit boards (PCBs). As the core substrate of PCBs, the copper-clad laminate (CCL) has electrical properties that are critically dependent on each component in its formulation. Among these, Flame retardant As a key functional additive for ensuring that boards meet the UL94 V-0 flame-retardant rating, its technical selection—whether in halogenated or halogen-free systems—directly affects the material’s dielectric loss (Df) performance and long-term service reliability. 
From the perspective of electrical performance, the presence or absence of halogens in flame retardants has a markedly different impact on signal loss. Traditional halogenated systems typically rely on bromine-based compounds. Although these flame retardants boast high flame-retardant efficiency, their large dipole moments and strong molecular polarity result in significant dielectric losses under the influence of high-frequency electric fields, leading to an increase in the dissipation factor (Df). For high-frequency hydrocarbon resin systems that demand a Df below 0.003, halogenated flame retardants often become the bottleneck restricting further performance improvements. In contrast, high-performance... Halogen-free flame retardant (For example, phosphorus-nitrogen-based or reactive flame-retardant systems) through the design of molecular structures with depolarization properties, can maintain extremely low dielectric constants (Dk) and low loss, thereby minimizing energy attenuation during the transmission of high-frequency microwave signals.

In terms of reliability and thermal stability, the differences between the two are equally significant. Halogen-based systems, when thermally degraded, produce corrosive hydrogen halide gases, which pose a potential risk of corroding circuits in precision electronic devices. In contrast, modern halogen-free... Flame retardant Under high-temperature conditions, it exhibits superior carbonization capability, which can induce the resin to form a dense physical barrier, thereby raising the material’s thermal decomposition temperature (Td). Moreover, halogen-free flame retardants typically possess better hydrophobic properties, significantly reducing the substrate’s water absorption rate. A low water absorption rate ensures that PCBs maintain stable electrical insulation performance even in humid environments, effectively mitigating the risk of failure caused by ion migration (CAF). 
In summary, to strike a balance between fire safety and signal transmission efficiency, high-frequency, high-speed substrates are now undergoing a comprehensive transition toward halogen-free formulations. Desytek specializes in the collaborative R&D of high-performance halogen-free flame retardants and hydrocarbon resin systems. Through advanced interfacial optimization technologies, Desytek has not only resolved the conflict between flame retardancy and dielectric loss but has also significantly enhanced the dimensional stability of copper-clad laminates under extreme processing conditions. Choose scientifically sound approaches. Flame retardant The scheme has become the material foundation for building low-loss, high-reliability electronic systems.

De's'y'te'k New Materials We are a pioneering innovator in advanced optoelectronic materials. Our main products include: Hydrocarbon resin, high-frequency and high-speed hydrocarbon resin, crosslinking agent, coupling agent, reactive flame retardant You’re welcome to call our consultation hotline at 027-81801908 or 13971395740 (same number on WeChat). We’ll provide you with customized, professional services!