Digital LIGA: exploitation of droplet-on-demand inkjet printing to fabricate complex mechanical structures by electroforming

A novel 3D fabrication technique called digital LIGA is proposed, integrating functional digital printing with 3D microfabrication via electrodeposition. This allows for the realization of complex multilevel metallic structures without problems associated with merging growth fronts. To achieve this, we developed a gold nanoparticle ink, compatible with a SU-8 photoresist, for printing the digitally-defined seed layers. Using this ink, selective printing of a conductive seed layer on a multi-level photoresist was used along with subsequent electrodeposition. Defect-free complex multilevel metallic 3D structures were successfully prepared via this method.