Bottom-up Au Filling for Metallizations and High Aspect Ratio Features

Abstract

Bottom-up filling processes for fabrication of void-free, high aspect ratio, micrometer to millimeter size gold interconnects for wide bandgap materials or structures such as diffraction gratings have recently been demonstrated in near-neutral sulfite electrolytes containing micromolar concentrations of bismuth. The processes are highly efficient in time and material, the bottom-up deposition being entirely localized to filling of the recessed features and uniform across patterned substrates. Furthermore, deposition automatically stops under potentiostatic control, exhibiting a tell-tale potential signature upon filling under galvanodynamic control, at a controllable depth within patterned features. This presentation will present feature filling, deposit microstructure and understanding.