Search results for "Lithography"
showing 10 items of 242 documents
Nano-lithography by electron exposure using an Atomic Force Microscope
1999
Abstract We have used a conductive Atomic Force Microscope (AFM) tip to expose a very thin resist film. An exposing current of low energy electrons was induced from the tip to the substrate by applying a small bias voltage. Uniform resist films as thin as 10 nm were fabricated using the Langmuir–Blodgett technique. To orient the defined pattern and to make electrical connections a special larger scale alignment structure was first defined by conventional electron beam lithography, either directly in the Langmuir–Blodgett resist film or in a separate first lift-off process with a thicker resist. The results from the one resist process gave conducting 50 nm lines with a 60 A thick vacuum depo…
The laser-plotter: A versatile lithographic tool for integrated optics and microelectronics
1992
Abstract The apparatus described here represents a low cost approach to artwork generation for integrated optics and microelectronics, in the resolution range around 2 μm. Its main characteristics are given below, together with some examples of the kind of patterns it can generate.
Artificial dielectric optical structures: A challenge for nanofabrication
1998
Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society.
Development of a microfluidic design for an automatic lab-on-chip operation
2016
Simple and easy to use are the keys for developing lab-on-chip technology. Here, a new microfluidic circuit has been designed for an automatic lab-on-chip operation (ALOCO) device. This chip used capillary forces for controlled and precise manipulation of liquids, which were loaded in sequence from different flowing directions towards the analysis area. Using the ALOCO design, a non-expert user is able to operate the chip by pipetting liquids into suitable inlet reservoirs. To test this design, microfluidic devices were fabricated using the programmable proximity aperture lithography technique. The operation of the ALOCO chip was characterized from the flow of red-, blue- and un-dyed deioni…
Charge dissipation in e-beam lithography with Novolak-based conducting polymer films
2008
Charging of common resist materials during electron beam (e-beam) writing leads to deflection of the electron beam path, which can result in significant pattern displacement. Here we report a new conducting polymer to eliminate charging. A common approach is to place the conducting layer underneath the e-beam resist layer. Conductivity equal or greater than 10(-4) S cm(-1) has been reported to prevent pattern displacement. Some other properties such as a flat surface layer, chemical inertness and insolubility in both the top resist solvent and the developer are also necessary. The way to achieve all these properties consisted in synthesizing a conducting polymer inside an insulating polymer…
Patterning of Conducting Polymers Using UV Lithography: The in-Situ Polymerization Approach
2012
We report on the in-situ polymerization of 3T with Cu(ClO4)2 inside several host polymers such as Novolak-based negative-tone photoresist, polystyrene (PS), poly(4-vinylphenol) (P4VP), poly(methyl methacrylate) (PMMA), and poly(4-vinylphenol)-co-(methyl methacrylate) (P4VP-co-MMA) to form an interpenetrating polymer network (IPN). Conducting IPN films in the order of 10–4–150 S/cm are obtained depending on the specific IPN composition. Moreover, the convenience of this synthetic approach has been demonstrated using a commercially available negative-tone photoresist based on Novolak as a host polymer. Novolak photoresist was properly formulated with 3T and Cu(ClO4)2 to preserve as far as pos…
Micropatterning of neurons using organic substrates in culture
1997
Abstract In this study, we have used spatially defined surfaces of organic thin films to micropattern the outgrowth of central nervous system neurons in culture. Glass substrates were first chemically modified with synthetic peptides derived from an extra-cellular matrix protein laminin to couple a functionality that promotes a neuron-substrate interaction. The modification procedure was verified using X-ray photoelectron spectroscopy. The functionality of the modified glass surfaces was examined by growing neurons dissociated from mammalian central nervous tissues in culture. Spatially defined surfaces of the peptide were then fabricated by selectively attaching the peptide to coplanar sur…
A Combined Top-Down/Bottom-Up Approach for the Nanoscale Patterning of Spin-Crossover Coordination Polymers
2007
Molecular spin-crossover complexes of 3d–3d transitionmetal ions have been the focus of many researchers’ work because of their fascinating properties associated with the bistability of their electronic states (high spin (HS) or low spin (LS)). Although the origin of the spin-crossover phenomenon is purely molecular, the macroscopic behavior of these systems in the solid state is strongly determined by the interactions, of mainly elastic origin, between the transition-metal ions. Recently, remarkable progress has been made in the area of spin-crossover complexes with infinite one-, two-, or three-dimensional (1D, 2D, 3D) networks, the so-called coordination polymers. The purpose of this app…
Multi-scale simulations of polymeric nanoparticle aggregation during rapid solvent exchange.
2018
Using a multi-scale approach which combines both molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations, we study a simple and scalable method for fabricating charge-stabilized nanoparticles through a rapid solvent exchange, i.e., Flash NanoPrecipitation (FNP). This multi-scale approach is based on microscopic information from MD simulations and uses a KMC algorithm to access macroscopic length- and time scales, which allows direct comparison with experiments and quantitative predictions. We find good agreement of our simulation results with the experiments. In addition, the model allows us to understand the aggregation mechanism on both microscopic and macroscopic levels and det…
Magnetic molecular nanostructures: Design of magnetic molecular materials as monolayers, multilayers and thin films
2007
In this paper we summarize the importance and versatility of the molecular approach in the design and development of novel magnetic molecular materials. These materials processing, in order to obtain controlled molecular structures at the nanoscale, will also be remarked.