Vol.:(0123456789) 1 3 Journal of Electronic Materials (2021) 50:5327–5337 https://doi.org/10.1007/s11664-021-09060-x ORIGINAL RESEARCH ARTICLE Performance of Nano‑SiO 2 ‑Filled Poly(ether ketone ketone) Substrate for Fifth‑Generation Communication Deng Ming Pan 1  · Guang Kui Zhou 1  · Xiao Dong Zhi 1  · Tim Hsu 2  · Jen‑taut Yeh 1,2 Received: 17 January 2021 / Accepted: 10 June 2021 / Published online: 24 June 2021 © The Minerals, Metals & Materials Society 2021 Abstract Nano-SiO 2 particles have been incorporated into high-performance poly(ether ketone ketone) (PEKK) polymers to prepare satisfactory nanocomposite substrates for fifth-generation (5G) communication. Significantly lower dielectric constant (ε r ), dielectric loss (tan δ), and linear coefficient of thermal expansion (CTE) were found for each PEKK a x SiO 2 y nanocompos- ite film series incorporated with proper loadings of nano-SiO 2 particles. The dielectric characteristics measured for each PEKK a x SiO 2 y nanocomposite film series decreased to a minimum as the nano-SiO 2 loading approached an optimum value. Satisfactory ε r (2.74 at 1 MHz), tan δ (0.00309 at 1 MHz), and linear CTE (~ 37 × 10 −6 /°C) for 5G high-speed communica- tion were found for the nanocomposite film modified with the optimum nano-SiO 2 loading of 10 wt.%. The porosity values measured for each PEKK a x SiO 2 y film series remained nearly zero then increased abruptly as the nano-SiO 2 loading exceeded 10 wt.%. The free volume characteristics evaluated for each PEKK a x SiO 2 y film series increased to a maximum as the nano- SiO 2 loading reached the optimum value of 10 wt.%. Possible explanations for the noticeably reduced dielectric and linear CTE characteristics found for PEKK a x SiO 2 y composite films are proposed. Keywords Poly(ether ketone ketone) · nano-SiO 2  · dielectric · free volume property · 5G communication Introduction Fifth-generation (5G) wireless networks are designed to provide much higher speed and capacity and lower-cost services than fourth-generation networks. 1 Huge demand for more sophisticated integrated circuits and high-density storage devices has emerged owing to developments in the electronics and computerization industries during the last two decades. Electronics and/or microelectronics substrates for printed circuit boards (PCBs) or high-density storage devices require materials that possess high thermal stability, thermal conductivity, and stiffness, low dielectric constant (ε r ) and dielectric loss (tan δ), and linear coefficient of ther- mal expansion (CTE). 2,3 Meanwhile, the substrate’s linear CTE must be close to that of the adjacent silicon chips and copper (~17×10 -6 /°C) to reduce the possibility of device malfunction due to thermal fatigue. 2 The polymeric sub- strates most commonly used for 3G or 4G wireless networks are phenolic resin and glass-fiber-reinforced epoxy com- posites, which are reported to have relatively high linear CTEs of ~ 80 × 10 -6 /°C and ~ 52 × 10 -6 /°C, respectively. 2,4 Thermal fatigue is prone to occur at high temperatures or after long working cycles in the interfacial regions between copper foil and substrate materials. It has been generally reported 5-7 that the signal transmis- sion speed (V m/s) and propagation attenuation (A dB/m) can be evaluated according to Eqs. 1 and 2: (1) V = k c √  r , (2) A ∝ f tan √  r , Deng Ming Pan and Guang Kui Zhou contributed equally to this work and should be considered as co-first authors. * Jen-taut Yeh jyeh@mail.ntust.edu.tw 1 Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials Ministry of Education, Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymeric Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan, China 2 Polymics Ltd., State College, PA 16803, USA