Design of metalized polyether-ether-ether-ketone based on semi-additive manufacture for 5G applications: from bottom-up assembly to selective electroplating†

5G technology urges high-volume demands and high-value performances of printed circuit boards. Due to the skin effect, substrates must maintain the roughness as low as possible for high-frequency signal transmission. However, there is a trade-off between roughness and adhesive strength at the interface. Herein, based on semi-additive manufacture, 3-glycidyloxypropyltrimethoxysilane is selected to bridge polyether-ether-ketone (PEEK) and copper at the nanoscale interface. Followed by electroless plating, a metal film is planted on the insulating substrate for selective electroplating of copper. The interfacial adhesive strength reaches the 5B level according to the criteria of ASTM D3359. Using multiscale experimental techniques, the interfacial characteristics are measured to analyze the physical structures, chemical compositions, and adhesive strength. Then we design and prepare a microstrip line for assessing passive intermodulation during 700–2200 MHz. Furthermore, quantum chemical calculations and molecular dynamics simulations are carried out to assess the mechanism of interfacial strengthening.