High Aspect Ratio via Filling by Electroless Deposition Enabled by Supercritical Carbon Dioxide

This work reports filling of blind-hole, high aspect ratio (AR) nano trenches by NiP electroless deposition (ELD) enabled under supercritical carbon dioxide (SC-CO
₂
). SC-CO
₂
ELD effectively filled blind trenches with AR ≤ 1:60 (diameter: 83 nm, depth: 5 μm), which was twice higher compared to that achieved by conventional ELD under similar experimental conditions. No pre-deposition of seed layers or surface pre-treatment to increase wettability was performed, and trench filling was achieved only through application of SC-CO
₂
. Moreover, P content in the nanowires was found to vary according to nano trench aspect ratio.