Novel Ultra-Low Dielectric Loss Tangent Resin with High Flame Retardancy for High-Frequency Printed Wiring Boards

To ensure high signal quality when operating in the high-frequency range, transmission losses must be reduced, and a low dielectric loss tangent is required for the insulating materials in printed wiring boards (PWBs). The dissipation factor of PWB materials for use in 5G base stations is at the 0.002-0.005 level, but post-5G and 6G equipment will require factors of 0.002 or even 0.001 or less. Olefins and other materials are being considered for use as next-generation low dielectric constant materials, but there is a trade-off between a low dielectric loss tangent and flame resistance for these materials, and no material that combines both properties has been reported to date. In this work, we have developed a novel material that offers both a low dielectric loss tangent and high flame retardance. This material has a dielectric loss tangent of less than 0.001, which is very low when compared with the PPE-based materials currently in use. Furthermore, the chemical structure has been optimized to provide flame resistance equivalent to that of the UL-94 V-0 standard. In addition, it also has thermosetting properties and a high glass transition temperature, which are required for PWB materials, and is expected to be a next-generation low dielectric loss tangent material.