Filling through-silicon vias with conductive ferromagnetic silver-iron composite

This paper demonstrates a novel magnetic induced injection method of ferromagnetic composite to build electrically conductive through-silicon vias (TSVs). The through conductive via is filled with conductive ferromagnetic composite by attractive magnetic force. The composite is made of the mixture of silver and iron nanoparticles. SU-8 2002 is covered on the side walls of via as an insulating material by a low vacuum suction. After thermal curing process, the dielectric layer can possess an electric field as high as 5×10⁶ V/cm. All of the fabrication steps are completed below 100 C. The TSVs can allow a current density of 6×10⁷ A/m². The leakage current is 2×10^-6 A at 50 V. After DC electrical sintering, the resistances of each TSV is less than 0.85 Ω.