Contrast Modulation in DNA‐Based Lithography: Pathway to 3D Nanofabrication

This paper reports an approach to fabricate 3D nanoscale patterns using a modified 2D DNA template in a single step of pattern transfer. Triangular‐shaped DNA origami was modified with streptavidin and used as the template for HF‐vapor etching of SiO 2 to produce negative tone triangular patterns of more than 28 nm in depth and 22 nm in width. Streptavidin molecules locally increase the rate of HF etching reaction, increasing vertical contrast of the transferred pattern by 39% but without noticeable change in the width. The result is consistent with the hypothesis that streptavidin increases adsorption of water, which is a catalyst for the HF vapor etching of SiO 2 . Our work points to a new approach to accelerate and simplify 3D nanofabrication.