Metallization of high density TSVs using super inkjet technology

Abstract

Filling or metallization of the through silicon vias (TSVs) with the conductive materials to act as vertical electrical interconnections through the wafers, is one of the key steps in the microelectromechanical systems (MEMS) wafer level packaging. Previously, metallization of the vias with inkjet printing technology is demonstrated. However, little attention has been paid to the possibility of metallization of high density TSVs; because drop diameters of conventional inkjet printers are larger than the top diameter of thin vias. Therefore, in this work we investigate the potential of super inkjet (SIJ) technology with 0.1 femtoliter droplets to metallize the vias with top diameter of 23 µm using three different silver nanoparticle inks. The filling processes are monitored by the observation camera and after the sintering, cross-sections of the vias are studied by the optical and scanning electron microscope (SEM).