Enhancing thermal conductivity of the insulating layer of high-frequency copper clad laminates via incorporating surface modified spherical hBN fillers

The rapid development of modern information technology needs highly thermal-conductive with high-frequency copper clad laminates (HFCCLs) as a key point. In this study, ShBN (spherical hexagonal boron nitride) and ShBN/KH550 (surface modified by KH550) were used as fillers to enhance the thermal conductivity for the insulating layer of HFCCLs. Due to the merits of not only the rotational symmetry for effective thermal networks, but also a compatibility with the polymer matrix, the ShBN/KH550 filled with HFCCLs (SK-CCLs) could reach a high value of 1.18 W m⁻¹K⁻¹ when the content of the filler was 63 wt%. On the other hand, the incorporation of ShBN and ShBN/KH550 fillers had led to the decrease the dielectric losses with a low dielectric permittivity even at a high testing frequency of 5 GHz. In addition, the peel strength and flexural strength of the HFCCLs were not significantly reduced with the addition of either ShBN or ShBN-KH550 fillers, showing the same downward trend. This study presents a new direction to promote the conductive insulating layer for HFCCLs to meet the high requirement of upcoming 5G or 6G era.