Novel Low-dielectric Fluorinated Carbon Fiber/Polyimide Materials with High Elongation

With the development of wafer-level packaging (WLP), polyimide materials with low-dielectric and high-elongation properties are urgently needed in redistribution layers (RDLs). Incorporating fillers into polyimide materials to enhance the properties of polyimide composites is one of the most compatible and lowest cost solutions. However, the degradation of composite materials performance caused by uneven filler dispersion is one of the key issues. Herein, novel low-dielectric fluorinated carbon fiber/polyimide (FCF/ PI) materials were prepared by high-power ultrasonic dispersion technology to alleviate the problem of filler dispersion. The dielectric, mechanical and heat resistance properties of FCF/ PI with different filler additions were characterized. The dielectric properties of 1.0 wt% FCF/PI composite film are 3.02 (Dk) and 0.0198 (Dl) at 5 GHz. And the elongation at break of 1.0 wt% FCF/PI film can reach more than 50%. In addition, the
${T_{5\%}}$
and
$\mathbf{T}_{\mathrm{g}}$
of all FCF/ PI composites were above 550 °C and 400 °C, respectively. Therefore, the novel low-dielectric FCF/PI materials with high elongation have prospects in the field of advanced packaging.