Inkjet filling of TSVs with silver nanoparticle ink

Abstract

Through silicon vias (TSVs) have been used in 3D packaging of microelectronic devices and MEMS devices, where they provide electrical interconnections through the stacked wafers and devices. Currently, chemical vapor deposition (CVD) or electroless deposition are used to partially or fulfill the vias. However, these methods are time consuming. Thus, the potential of inkjet printing to linearly fill the TSVs with silver nanoparticle ink, as an additive digital fabrication technique, will be reviewed. This technique could make the via metallization process much faster, agile, and cost-efficient. In this study, vias with the outer diameter of 80μm and depth of around 115μm fabricated with dry-reactive ion etching (DRIE) are filled with a silver nano-particle ink NPS-J from Harima Chemicals using Dimatix inkjet printer (DMP-2800) with 10pl cartridge. Substrate temperature was found to be potentially more affective to print more droplets rather than increasing waiting time. Moreover, printing on the 60 °C substrate with no delay was optimum considering the uniformity, thickness and quality of the coverage.