A scanning-helium-ion-beam microscope is now commercially available. This microscope can be used to perform lithography similar to, but of potentially higher resolution than, scanning electron-beam lithography. This article describes the control of this microscope for lithography via beam steering/blanking electronics and evaluates the high-resolution performance of scanning helium-ion-beam lithography. The authors found that sub-10 nm-half-pitch patterning is feasible. They also measured a point-spread function that indicates a reduction in the micrometer-range proximity effect typical in electron-beam lithography.

Zone-plate array lithography ͑ZPAL͒ is a maskless lithography scheme that uses an array of shuttered zone plates to print arbitrary patterns on a substrate. An experimental ultraviolet ZPAL system has been constructed and used to simultaneously expose nine different patterns with a 3ϫ3 array of zone plates in a quasidot-matrix fashion. We present exposed patterns, describe the system design and construction, and discuss issues essential to a functional ZPAL system. We also discuss another ZPAL system which operates with 4.5 nm x radiation from a point source. We present simulations which show that, with our existing x-ray zone plates and this system, we should be able to achieve 55 nm resolution.

Direct additive-layer fabrication of nanostructures is a widely sought goal, which is not possible using traditional layered resist optical and electron-beam lithographic techniques. However, recently, it has been shown that certain metallic and semiconducting nanoparticles capped with protective organic groups are promising “inklike” resist materials for patterning a variety of electronic and mechanical structures [C. A. Bulthaup et al., Appl. Phys. Lett. 79, 1525 (2001)]. Several groups have successfully patterned single-layer gold nanoparticle films by means of direct electron-beam writing [X. M. Lin, R. Parthasarathy, and H. M. Jaeger, Appl. Phys. Lett. 78, 1915 (2001); T. R. Bedson, R. E. Palmer, T. E. Jenkins, D. J. Hayton, and J. P. Wilcoxon, Appl. Phys. Lett. 78, 1921 (2001); L. Clarke et al., Appl. Phys. Lett. 71, 617 (1997)]. In this work, we apply these materials in a new lithographic mode, using an electron beam to cause direct sintering of these 2–10 nm nanoparticles, building structures of multiple layers and multiple materials with linewidth resolutions of 80–100 nm.

Articles you may be interested inFast aerial image simulations using one basis mask pattern for optical proximity correctionWe describe a unified approach to measuring alignment and gap with nanometer detectivity between two planar objects ͑e.g., a mask and a substrate͒ in close proximity. The method encodes lateral position in the phase of interference fringes, formed by diffraction from grating and checkerboard alignment marks, designed to enable a wide acquisition range. For gapping, the method incorporates, in the same mark, coarse-gap detection ͑30-300 m͒ and absolute-gap detection at sub-30 m using a chromatic Fabry-Pérot scheme. Fine detection of sub-30 m gaps is inferred from the frequency and phase of fringes, calibrated using the chromatic Fabry-Pérot. Illumination with a variable-bandwidth source enables either ''achromatic'' aligning or ''chromatic'' gapping. Sub-nanometer detection and feedback control of mask position is demonstrated in X, Y, and . Overlay of exposed patterns is demonstrated to be Ͻ3 nm.

We demonstrate the application of a high-sensitivity alignment method called interferometric-spatial-phase imaging ͑ISPI͒ to a nanometer-level overlay in fluid-immersion lithography, using step-and-flash imprint lithography as the test vehicle. As a stringent test we used alignment marks that consist of pure phase gratings in a fused silica template, immersed in a fluid of similar refractive index, resulting in a low-contrast alignment signal. Feedback control of alignment is demonstrated with mean= 0.0 nm and = 0.1 nm using an immersed template. Overlay results, with UV-exposed imprint fluid, were limited to ϳ4 nm, due to a mechanical disturbance. Because ISPI enables continuous monitoring of the alignment signal, we were able to identify the origin of the mechanical disturbance and can eliminate it in future experiments. In addition, we demonstrate the ability to actively reduce misalignment during the progression of crosslinking in the imprint fluid.