DNA Origami for Silicon Patterning.

DeoxyriboNucleic Acid (DNA) origami architectures are a promising tool for ultimate lithography due to its ability to generate nanostructures with a minimum feature size down to 2 nm. In this paper, we developed a method for silicon (Si) nano-patterning to face up current limitations for the high-resolution patterning with standard microelectronic processes. For the first time, a 2 nm thick 2D DNA origami mask, with specific design composed of three different square holes (with a size of 10 and 20 nm), is used for positive pattern transfer into a Si substrate by using a 15 nm thick silicon dioxide (SiO2) layer as intermediate hard mask. First, the origami mask is transferred onto the SiO2 underlayer, by an HF vapor-etching process. Then, the Si underlayer is etched using an HBr/O2 plasma. Each hole is transferred in the SiO2 layer and the 20 nm size holes are transferred in the final stack (Si). The resulting patterns exhibited a lateral resolution in the range of 20 nm and a depth of 40 nm. Patterns are fully characterized by AFM, SEM, FIB-TEM and ellipsometry measurements.