Advanced Low-Loss and High-Density Photosensitive Dielectric Material for RF/Millimeter-Wave Applications

Electrically low-loss and high-density interconnection between components in a package have been one of the most critical metrics for next-generation 5G millimeterwave packages. This paper describes an innovative low-loss photosensitive dielectric material, which enables sub-$10\ \mu \mathrm{m}$ photo-patterning and shows low dissipation factor, known as Df. Dielectric properties providing low-loss interconnects were characterized by ring-resonator method. The results showed a dielectric constant (Dk) of 2.8 and a dissipation factor (Df) of less than 0.005 up to 40 GHz. This material is also designed to have a comparatively low curing temperature of 200°C, high elongation >50%, and high adhesion, and low surface roughness. This paper also presents the demonstration of low-loss and high-density signal routings using dual damascene process with the material. The innovative photosensitive dielectric material, reported in this paper, is a promising candidate to enable high-performance, high-density fan-out and interposers for RF and 5G mm-wave applications.