Fabrication of electrode arrays with nanoscale direct laser writing: first results

Abstract

Direct laser writing (LDW) technology originated as a simple and masking-free method for manufacturing large-area submicron structures. The spatial resolution of LDW technology based on a standard photochemical process is usually limited to hundreds of nanometers in visible light due to the diffraction limit. During photochemical processing, the size of the element implemented in the acceptor material (organic photoresist) is equal to or greater than the size of the focused laser spot incident on the acceptor material, despite the fact that the laser beam has a Gaussian distribution, since the organic photoresist used for photochemical lithography has a low reaction threshold. For photothermal lithography, the element size can be equal to the size of the focused laser spot or much smaller than it, since the inorganic resist used for photothermal lithography has a much higher threshold. When the laser dose corresponds well to the threshold value of the inorganic photothermal material, only the central region, much smaller than the focused laser spot with a Gaussian energy distribution, can exceed the threshold of the reaction of the inorganic material, which leads to a decrease in the size of the element. However, the same property can be used to produce extremely small gaps. For the production of gaps, the LDW technique on chromium films is proposed, using the photothermal principle, in which the acceptor material is sensitive to a certain thermal threshold, and thus the diffraction limit is overcome. Changing the laser radiation dose and recording speed allows controlled adjustment of the gap size. The presented direct laser recording technology opens up new possibilities at the nanoscale, especially in the field of nanoproduction with a width of less than 100 nm.

Speaker

Sergey D. Poletayev
Image Processing Systems Institute, NRC "Kurchatov Institute"
Russia

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