Fabrication of 2D silicon nano-mold based on sidewall transfer

A method based on the sidewall transfer technique for fabricating two-dimensional (2D) nano-mold on a silicon substrate was developed. Instead of using expensive nanolithography, the authors fabricated 2D silicon nano-mold using standard ultraviolet lithography, conformal deposition of gold by radio frequency sputtering, argon sputter etching and deep reactive ion etching (DRIE). This technique enables the generation of very fine geometries with nanoscale dimensions without the electron-beam (e-beam) lithography equipment or other additional lithography techniques. Based on SF₆, O₂ and C₄F₈ plasmas, a vertical mold profile and a minimum scallop size of 30 nm were obtained by optimising DRIE parameters. For smooth mold surfaces, the authors report and demonstrate a new mechanism of removing grass obtained during inductively coupled plasma etching. With this technique, very uniform 2D silicon nano-molds consisting of 200 nm wide, 200 nm high and 4.3 mm long bar arrays have been successfully fabricated.