Effect of hexagonal boron nitride on the thermal and dielectric properties of polyphenylene ether resin for high-frequency copper clad laminates

As the base material of the printed circuit boards (PCBs), copper clad laminates (CCLs) with high thermal conductivity, low dielectric loss and high peel strength have been greatly desired especially for the upcoming 5G age. In this study, hexagonal boron nitride (hBN) was firstly introduced into the polymer insulating filler (Polyphenylene ether resin, PPER) of copper clad laminates for high frequency applications. The as-obtained CCLs exhibited a high thermal conductivity up to 1 W/m·K and a low dielectric loss of ~4 × 10−3. Meanwhile, the interface tailoring of hBN was also tried by SiO2 coating, which enhanced the peel strength to a maximum value of 1.1 N/mm, but changed the thermal conductivity behavior of the CCLs from the Agari's linear model to the modified quadratic model due to the interfacial thermal resistance effect of SiO2 coating on hBN. Moreover, the flexural strength and water absorption were also tested. The results revealed that, comparing with the related composite materials reported in literature and commercial products, the CCLs obtained in this paper have outstanding advantages in thermal and dielectric properties, validating the high potential of the present CCLs for use in high frequency PCBs.