Lithography – literally "stone writing" – is a process that is fundamental to the manufacture of integrated circuits. It is improvements in this process that have largely enabled the spectacular advances that have been made in the field of microelectronics over the last three decades.

We discuss the fabrication of various one and two-dimensional chromium nanostructures. A chromium atomic beam effusing out of a thermal oven is first transversally laser cooled. This well-collimated beam is then structured and focused by the optical dipole force in a periodic light field. By introducing a substrate at the focus of the atomic beam we are able to capture this pattern directly. We discuss a few applications and challenges of this young lithography technique.

Electron-beam lithography.

Lithography using nano-lens arrays made of light

We describe techniques for performing photolithography and electron beam lithography in succession on the same resist-covered substrate. Larger openings are defined in the resist film through photolithography whereas smaller openings are defined through conventional electron beam lithography. The two processes are carried out one after the other and without an intermediate wet development step. At the conclusion of the two exposures, the resist film is developed once to reveal both large and small openings. Interestingly, these techniques are applicable to both positive and negative tone lithographies with both optical and electron beam exposure. Polymethyl methacrylate, by itself or mixed with a photocatalytic cross-linking agent, is used for this purpose. We demonstrate that such resists are sensitive to both ultraviolet and electron beam irradiation. All four possible combinations, consisting of optical and electron beam lithographies, carried out in positive and negative tone modes have been described. Demonstration grating structures have been shown and process conditions have been described for all four cases.

https://iopscience.iop.org/article/10.1088/1361-6528/aa8bd5/pdf

Electron-beam lithography.

Citations

Lithography using nano-lens arrays made of light

Combination photo and electron beam lithography with polymethyl methacrylate (PMMA) resist.

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