High aspect ratio sub-100 nm silicon vias (SVs) by metal-assisted chemical etching (MaCE) and copper filling

Metal assisted chemical etching (MaCE) is a promising technology for next-generation micro- and nano-semiconductor fabrication. In this technology, noble metals are used as catalyst to anisotropically etch bulk materials in solution. Here we report the first silicon vias with sub-100 nm diameter etched by MaCE. The distinct structure of thus fabricated vias enables the successful copper filling from the bottom, which is demonstrated by scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDS). This work shows the applicability of nano-scale interconnection in 3D package from the view of fabrication. Also, the reported technique bears great significance in functional filling of semiconductor for nano-photonic devices as well as template-based synthesis of functional nanomaterials.