Showing papers on "Proximity effect (electron beam lithography) published in 2016"

Photolithography reaches 6 nm half-pitch using EUV light

Abstract: EUV interference lithography records the interference pattern of two diffracted, coherent light beams, where the pattern resolution is half the diffraction grating resolution. The fabrication of diffraction grating masks by e-beam lithography is restricted by the electron proximity effect and pattern transfer limitations into diffraction efficient materials. By patterning HSQ lines at a relaxed pitch to avoid the electron proximity effect, depositing conformal iridium via atomic layer deposition, followed by ion milling the top and bottom iridium and HSQ removal, we fabricated iridium diffraction gratings at double the line spacing of the original HSQ lines. 6 nm half-pitch patterns were achieved using these masks marking a new record resolution in photolithography.

Photolithography reaches 6 nm half-pitch using extreme ultraviolet light

Abstract: Extreme ultraviolet interference lithography records the interference pattern of two diffracted, coherent light beams, where the pattern resolution is half the diffraction grating resolution. The fabrication of diffraction grating masks by e-beam lithography is restricted by the electron proximity effect and pattern transfer limitations into diffraction efficient materials. By patterning HSQ lines at a relaxed pitch to avoid the electron proximity effect, depositing conformal iridium via atomic layer deposition, followed by ion milling the top and bottom iridium and HSQ removal, we fabricated iridium diffraction gratings at double the line spacing of the original HSQ lines. Line/space patterns of 6-nm half-pitch patterns were achieved using these masks, marking a new record resolution in photolithography.

Highly scalable resistive switching memory in metal nanowire crossbar arrays fabricated by electron beam lithography

Abstract: Resistive switching memories (RRAMs) based on oxides are promising nonvolatile memories with numerous advantages in cell structure, switching speed, operation power, and fabrication process. To promote practical application, however, the scalability issue of RRAMs should be investigated. In this work, the maskless electron beam lithography (EBL) was used to fabricate very small structures in the electron beam resist layer, which were subsequently transferred to a metal and oxide film by the lift-off process. Metal nanowires with a minimum width of 9 nm and arrays with such nanowires were fabricated by optimizing the pattern design and by correcting the electron beam proximity effect. By combining three processes of EBL, film deposition, and lift-off, Ti/HfO2/Pt-based RRAM devices with a minimum size of 10 nm integrated into a crossbar array were successfully fabricated. The fabricated devices exhibit good memory performance, including low operation voltage, good endurance, retention, uniformity, and scala...

Resist Assisted Patterning

Abstract: Helium ion beam lithography (HIL) has been demonstrated as a promising alternative to electron beam lithography (EBL) for R&D purposes, offering high-resolution lithography at high pattern densities. This chapter reviews focused He ion beam lithography, providing a detailed discussion on the ion beam-resist interaction mechanisms and latest experimental results in this field. In addition, impact of ion shot noise is examined, a comparison to He-ion beam milling is made, and future directions are mentioned.

Shape positional accuracy optimization via writing order correction

Abstract: Shape positional accuracy is a ubiquitous challenge when writing critical features using electron beam (e-beam) lithography. Positional accuracy can be particularly important when patterning for dense pattern arrays often found in plasmonic device structures. These arrays contain structures critically placed within a few tens or hundreds of nanometers apart from one another, whereby poor positional accuracy on the same order of magnitude would impact overall device performance. The sources of positional accuracy are varied on an e-beam lithography system and can include, but are not limited to beam drift, surface charging, environmental noise, and temperature to name a few. This work demonstrates the impact of shape writing order on sub-100 nm features to tolerate these potential sources of shape positional errors. The shape positional accuracy of both proximity effect corrected (PEC) and non-PEC array patterns are studied using a 20 MHz fixed clock 50 keV Gaussian spot electron beam lithography system ex...

Study of negative electron beam nanoresist HSQ on GaAs substrate

Abstract: The aim of this paper is to characterize Hydrogen Silsesquioxane (HSQ) inorganic negative electron resist on GaAs substrate at 40 keV electron energy. The influence of process parameters on resist profiles was investigated with the aim of obtaining vertical sidewalls. The values of the proximity effect function parameters (β f , β b and η E ) were calculated using Monte Carlo approach. Observation of HSQ resist profiles were done for a set of linewidth dimensions.