Ion Beam Lithography and Nanofabrication: A Review

Abstract

To overcome the diffraction constraints of traditional optical lithography, the next generation lithographies (NGLs) will utilize any one or more of EUV (extreme ultraviolet), X-ray, electron or ion beam technologies to produce sub-100 nm features. Perhaps the most under-developed and under-rated is the utilization of ions for lithographic purposes. All three ion beam techniques, FIB (Focused Ion Beam), Proton Beam Writing (p-beam writing) and Ion Projection Lithography (IPL) have now breached the technologically difficult 100 nm barrier, and are now capable of fabricating structures at the nanoscale. FIB, p-beam writing and IPL have the flexibility and potential to become leading contenders as NGLs. The three ion beam techniques have widely different attributes, and as such have their own strengths, niche areas and application areas. The physical principles underlying ion beam interactions with materials are described, together with a comparison with other lithographic techniques (electron beam writing and EUV/X-ray lithography). IPL follows the traditional lines of lithography, utilizing large area masks through which a pattern is replicated in resist material which can be used to modify the near-surface properties. In IPL, the complete absence of diffraction effects coupled with ability to tailor the depth of ion penetration to suit the resist thickness or the depth of modification are prime characteristics of this technique, as is the ability to pattern a large area in a single brief irradiation exposure without any wet processing steps. p-beam writing and FIB are direct write (maskless) processes, which for a long time have been considered too slow for mass production. However, these two techniques may have some distinct advantages when used in combination with nanoimprinting and pattern transfer. FIB can produce master stamps in any material, and p-beam writing is ideal for producing three-dimensional high-aspect ratio metallic stamps of precise geometry. The transfer of large scale patterns using nanoimprinting represents a technique of high potential for the mass production of a new generation of high area, high density, low dimensional structures. Finally a cross section of applications are chosen to demonstrate the potential of these new generation ion beam nanolithographies.

A threshold for laser-driven linear particle acceleration in unbounded vacuum

“…We consequently derive a general formula for the acceleration threshold of such schemes and support our conclusion with the results of numerical simulations over a broad range of parameters for different kinds of pulsed laser beams.Energetic particle beams are crucial to the progress of fields across the spectrum of science and technology, from cancer treatment [1] to particle physics [2] to inertial confinement fusion [3], nanolithography [4] and radioactive waste management [5].High-intensity laser systems, made possible by chirped-pulsed amplification [6], can provide accelerating gradients that surpass those of conventional accelerators by as much as six orders of magnitude [7], paving the way to an era of table-top particle accelerators and table-top x-ray laser systems. Although plasma-based acceleration schemes [8] have had much experimental success, the possibility of accelerating particles in vacuum [9,10] remains of great interest since the absence of plasma would preclude problems associated with the inherent instability of laser-plasma interactions.…”

“…Energetic particle beams are crucial to the progress of fields across the spectrum of science and technology, from cancer treatment [1] to particle physics [2] to inertial confinement fusion [3], nanolithography [4] and radioactive waste management [5].…”

Ion-Beam-Induced Luminescence Analysis of β-SiAlON:Eu Scintillator under Focused Microbeam Irradiation

“…The radiation hardness of ionization particle detectors is a key issue for accelerator experiments, particularly for the utilization of focused ion microbeam probes for micometer-sized material modifications (1,2) or microanalysis. (3,4) Irradiation by a focused microbeam significantly degraded the response of particle detectors because of its intense energy transfer to the detector body.…”

Focused Ion Beam Micro Machining and Micro Assembly

“…For this reason, FIB has found wide applications in many areas, such as MEMS, optical, micro fluidic devices and so on [1]. Recently, application of FIB system has seen ever-increasing applications in micro machining and micro assembly, through integration with other powerful micro/nano facilities such as scanning electron microscopy (SEM), gas injection system (GIS) and nano-manipulator systems.…”