Novel Low Dk/Df Photoimageable Dielectric for Redistribution Layer

We have developed, based on our original resin design, a new photoimageable dielectric (PID) with superior dielectric properties when compared to conventional redistribution layer (RDL) materials. The dielectric constant (Dk) achieves values of
$\mathbf{Dk} \leq \mathbf{2.8}$
and the dielectric loss tangent (Df) values of
$\mathbf{Df}\leq \mathbf{0.005}$
. Furthermore, this negative tone-type PID can be wet-etch developed in organic solvent and shows good lithographic performance allowing via sizes smaller than
$10\ \mu \mathrm{m}$
, After being developed, it can be cured at a relatively low temperature, 200°C or less, and exhibits lower shrinkage when compared with general PID materials, such as photosensitive polyimide. All of the explained above is achieved without worsening the thermomechanical behavior and reliability requirements of conventional RDL materials. In this paper, we would like to present the characteristics and advantages of this resin material in detail.