High-resolution patterning with remarkable customizability has stimulated the invention of numerous scanning probe lithography (SPL) techniques. However, frequent tip damage, substrate-film deterioration, low throughput, and debris amassing in the patterned region are the inherent impediments that have precluded obtaining patterns with high repeatability using SPL. Hence, SPL still has not got wider acceptance for industrial fabrication and technological applications. Here, we introduce a novel SPL technique, named water electrolithography (W-ELG), for patterning at the microscale and potentially at the nanoscale also. The technique operates in the non-contact mode and is based on the selective etching, via an electrochemical process, of a metallic film (e.g., Cr) submerged into water. Here, the working of W-ELG is demonstrated by scribing a pattern into the Cr film by a traversing cathode tip along a preset locus. A numerical analysis establishing the working principles and optimization strategies of W-ELG is also presented. The tip-sample distance and tip-diameter are identified as the critical parameters controlling the pattern creation. W-ELG achieved a throughput of 1.5 × 107 μm2/h, which is the highest among the existing SPL techniques, while drawing 4 μm wide lines, and is also immune to deleterious issues of tip damage, debris amassment, etc. Therefore, the resolution of these inherent impediments of SPL in W-ELG sets the stage for a paradigm shift that may now translate the SPL from academic exploration to industrial fabrications.

The electric field-induced chemical reaction in Cr thin film by a micro/nano-probe has been recently reported with detailed characterization. Although the phenomenon is employed for micro-nano fabrication, this can act as a reliability failure, where Cr is used as an adhesion layer or main interconnects in microelectronic circuits. Here, we present an investigation on the role of electric current density for such failure using a specifically designed sample. A 100 μm width and 100 nm thin Cr film is deposited perpendicular to the Pt film of similar dimensions. The anode probe (20 μm diameter) is positioned onto the Pt film, whereas the cathode probe onto the Cr film. It is observed that the chemical reaction, for an applied voltage, initiates at the edge of the Pt film and not at the cathode probe. The localized chemical reaction causes to damage the interconnection line. The analysis based on the COMSOL multiphysics simulation illustrates that the chemical reaction evolves at the high current density locations. The study also builds a fundamental understanding of the mechanism of evolution of patterning by electric field-induced chemical reactions.

Chromium films with a thickness of 10–40 nm deposited onto silicon substrates by magnetron sputtering are subjected to the action of electric current induced by the tip of an atomic force microscope (AFM) cantilever in air under regular environmental conditions. The melting process at the nanoscale, electric field-induced migration of material, and the chemical reaction of chromium oxidation that occur in melt craters formed around the region affected by the current are investigated using optical and scanning electron microscopies, AFM, and Raman spectroscopy. The flow of melted material induced by electric current is accompanied by the formation and motion of an array of spherical nanoparticles in the melt crater along its periphery. We propose that the formation of nanodrop array at relatively low current densities can be explained by the chromium oxidation reaction and the surface tension of melted material on the silicon substrate.

Electric field-induced "etching" of Cr film is a tip-based patterning technique that is used to create micro- and nano-sized trenches in the film under ambient conditions. The experimental data obtained in this study reveals that the etching of Cr occurs via the formation of water-soluble CrO3, which spontaneously forms at the cathode tip when a large electric field is applied using a pointed tip in the presence of humid air. By varying experimental conditions, such as vacuum level, gaseous environment, temperature, and humidity, the kinetics of the electric field induced chemical reaction at the cathode was studied. Subsequently, the obtained insights were incorporated into a model to explain the mechanism of the phenomenon. Water vapor in the air surrounding the tip acts as a limiting reactant in the electrochemical oxidation of Cr to CrO3. Insights obtained from this study open new avenues for technological improvements in the patterning technique using this chemical method.

Nano films of chromium with thicknesses from 20 to 200 nm were deposited on silicon substrates and were treated by electric current induced by AFM tip in ambient atmosphere. The melting on the nanoscale, electric current induced migration of the material and chemical reaction of oxidization of chromium were revealed in melting craters around the point of application of the current by optical and electronic scanning microscopy, AFM, and Raman spectroscopy. The flow of the material induced by electric current is accompanied by formation and motion of the matrix of the spherical nanoparticles (beads) in the crater of melt on its periphery. The reaction of chromium oxidation and surface tension of the melted material on the silicon substrate are expected to be responsible for the matrix of nano beads formation under comparatively small currents. Raman spectroscopy confirms that in the vicinity of the periphery of the melted craters around AFM tip application, the beads of oxide phase Cr2O5 are present.

Here, we introduce electrolithography, which is a recently developed lithography technique. Upon passage of electric current through a pointy cathode electrode placed on Cr film leads to formation and liquefaction of a Cr compound, which then flows away from the cathode in a radially symmetric fashion, thereby removing the Cr layer. If the pointy electrode, akin to a stylus, is traversed along a path, a trench will be patterned in the Cr film, which can then be transferred to other materials. Firstly, we describe the process of electrolithography and then we discuss the effects of the force applied on the stylus and the polymer layer placed in between substrate and Cr film on this lithography process. Finally, we discuss future prospects of electrolithography.

The recently developed technique of micro-nano pattern drawing by electrolithography process necessitates controlled probe-tip movement on a predefined path. Here we report development of a specific micropositioner system for drawing patterns at micrometer scale. Effect of different parameters on the patterns is studied. Probe-tip velocity and tip force are found to have major impact on the pattern-dimension.

In the report the physical basis of the development of electrical nano-contacts for bottom-up nanointegration are studied. For the fabrication of the electrical nano-contacts it is proposed to use the electromigration of micro - and -nano-drops of metals and 3D mechanical nanomanipulation of the nanowires. Nano-manipulation is provided by the usage of nanotweezers, produced from shape memory alloy composite. The process of the melting of the micro-wires was studied under the action of laser radiation and heating.

Electromigration in liquid metals can be used for mass transport over a considerable length with micro- and nano-scale flow features. Exploitation of this phenomenon, however, requires a sound understanding of the liquid metal flow under an applied electric field. Depending on the sign of the effective charge number, Z*, liquid metals flow along a set direction under the applied electric field. A few liquid metals, e.g. Ga, Sn, etc, flow in the direction of the electric field, while a few others, e.g. Pb, flow in the opposite direction. Here, we propose a new model for predicting the direction of the aforementioned flow for a given liquid metal. Our model incorporates Lennard-Jones potential into the cell model of liquids in order to calculate the value of Z* as a function of temperature. We then carry out experiments on a few metals to validate the model and show that it indeed correctly predicts the ensuing flow.