Nano-etching Using Nanodots Mask Fabricated by Bio-nano-process

An array of iron oxide nanodots with 6 nm diameter was used as a nanometer size patterning mask for inductively coupled plasma (ICP) etching process. The array of nanodots was fabricated by biological pathway named bio-nano-process. A cage protein, ferritin, was employed to accommodate an iron oxide core with 6 nm diameter and a two dimensional array of ferritin was made using their self-assembling ability. The array of ferritin was transferred onto a silicon wafer and the protein moiety was selectively eliminated by ozone treatment. The array of nanodots was used as a patterning dry-etching mask. The ICP etching using CHF3 gas at low temperature produced a combination of cone-shape peaks and plateaux. This result demonstrates the possibility that iron oxide nanodots array produced by bio-nano-process can be used as a dry-etching mask and that an array of nano-columns with high density could be produced. Taking a variety of bio-molecules which can accommodate inorganic materials into consideration, this bio-nano-process is expected to lead to a new approach for making nano-scale masks.