Integrating low dielectric constant and high thermal conductivity into composite films for 5G circuit package substrate

Abstract The high-frequency, integrated, and miniaturized circuits increase the risks of electromagnetic interference and heat accumulation. However, it is difficult for the traditional circuit package substrate to realize both low dielectric and high thermal conductivity, resulting in high-quality signal transmission and fast heat dissipation cannot be achieved simultaneously. Here, for the first time, composite films (hBN/LCPs) with low dielectric constant in high-frequency and high thermal conductivity are prepared based on liquid crystal aromatic polyesters (LCPs) and hexagonal boron nitride (hBN). The highest thermal conductivity of hBN/LCPs film reaches 0.696 W m −1 K −1 , which is 3.3 times higher than that of the pristine LCPs. In the simulation of wafer heat dissipation, hBN/LCPs film shows a maximum surface temperature decrease of over 20 °C compared to the pristine LCPs, showing the fast heat transfer ability. The dielectric constants and dielectric losses of hBN/LCPs films keep the low values in the range of 0.4–1 GHz, being less than 3.4 and 0.007, respectively, meeting the requirements of 5G communication devices. Meanwhile, the hBN/LCPs films show good mechanical strength and heat resistance. Therefore, a low-cost and facile method is developed to prepare composite films with low dielectric and high thermal conductivity for 5G circuit package substrates.