Confining Light to Deep Subwavelength Dimensions to Enable Optical Nanopatterning

Department of Chemistry, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
Science (Impact Factor: 33.61). 05/2009; 324(5929):917-21. DOI: 10.1126/science.1167704
Source: PubMed


In the past, the formation of microscale patterns in the far field by light has been diffractively limited in resolution to roughly half the wavelength of the radiation used. Here, we demonstrate lines with an average width of 36 nanometers (nm), about one-tenth the illuminating wavelength lambda1 = 325 nm, made by applying a film of thermally stable photochromic molecules above the photoresist. Simultaneous irradiation of a second wavelength, lambda2 = 633 nm, renders the film opaque to the writing beam except at nodal sites, which let through a spatially constrained segment of incident lambda1 light, allowing subdiffractional patterning. The same experiment also demonstrates a patterning of periodic lines whose widths are about one-tenth their period, which is far smaller than what has been thought to be lithographically possible.

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Available from: Hsinyu Tsai, Sep 15, 2014
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    • "Cao has obtained a nanoline with a width of 130 nm and nanodots with a diameter of 40 nm [26] by polymerization inhibiting, too. In Andrew's work, the nanolines with an average width of 36 nm were drawn employing absorbance modulation lithography [27]. Tanaka and Thiel have shown fabricating spatial voxel to sub-120 nm with the two-photo-absorption technology [28,29]. "
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    • "Although multi-axial electron-beam lithography has been proposed to increase throughput by using multiple beams in a parallel manner, there are difficulties in simultaneously regulating the multiple beam sizes and positions because of the thermal drift and electrical charge Coulomb interactions, which result in significant lens aberration567891011. Another optical maskless approach is to use assisting light beams to control the resist kinetics to achieve subdiffraction features121314. It provides a low-cost alternative, however the achievable feature size is still greatly affected by the spatial regulation capability of the far field optics. A major improvement in maskless lithography is thus critical in order to satisfy the demands in mass production for the semiconductor industry. "
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