Proximity effect (electron beam lithography)

About: Proximity effect (electron beam lithography) is a research topic. Over the lifetime, 940 publications have been published within this topic receiving 8508 citations.

Method for compensating for the E-beam proximity effect

Abstract: A method to compensate for the E-beam proximity effect which includes a post exposure, pre-development baking of the photoresist layer. The baking of the photoresist layer causes a migration of small, photo-active compound (PAC) molecules to increase the size of peripheral exposed areas so as to compensate for the exposure size variations caused by the proximity effect.

Proximity effect reduction in x‐ray mask making using thin silicon dioxide layers

Abstract: A novel method is reported for reducing the proximity effect in high‐resolution electron beam patterning of high atomic number materials such as tungsten. The method involves interposing a thin (50–400 nm) layer of SiO2 between the resist and the underlying high‐Z substrate. Examples are shown in which gratings of 0.2 μm lines with a 0.5 μm period were written without proximity effect compensation. Optimal intermediate layer thickness for the best resolution of the gratings is determined to be 200 nm. A Monte Carlo model of electron scattering including inelastic processes has been implemented to interpret our experimental results. The model presented shows that having the low atomic number SiO2 layer between the resist and the tungsten prevents the fast secondary electrons being generated at the surface of the tungsten from propagating back into the resist, suggesting a mechanism for proximity effect reduction. The results presented here have important practical applications for x‐ray mask making.

Manufacture of photomask, method for determining correction quantity of irradiation of resist material with electron beam and photomask

Abstract: PROBLEM TO BE SOLVED: To make it possible to manufacture a photomask without deviation of the size of etched mask patterns from a desired size by determining the correction quantity of irradiation with an electron beam in accordance with the density per unit block of the mask patterns SOLUTION: The relation between the density of the mask patterns to be formed and the fluctuation of the formed mask pattern size is first experimentally determined (sub-step SS-1A) A range where a process proximity effect extends is determined by using the data of the relation between the resulted plotting rate and size difference as a basis for correcting the process proximity effect (SS-1B) The correction quantity of the irradiation with the electron beam required for each of the respective plotting rates is experimentally determined (SS-1C) The density of the mask patterns in the respective unit blocks is determined by calculation with the range where the process proximity effect extends as a unit block (step S-2) The correction quantity of the irradiation at each of the respective unit blocks with the electron beam to be cast to a resist material is determined from the correction quantity of the irradiation and the mask patterns previously determined in accordance with the same

Observation of Superconducting Collective Modes from Competing Pairing Instabilities in Single‐Layer NbSe ₂

Abstract: In certain unconventional superconductors with sizable electronic correlations, the availability of closely competing pairing channels leads to characteristic soft collective fluctuations of the order parameters, which leave fingerprints in many observables and allow the phase competition to be scrutinized. Superconducting layered materials, where electron-electron interactions are enhanced with decreasing thickness, are promising candidates to display these correlation effects. In this work, the existence of a soft collective mode in single-layer NbSe2 , observed as a characteristic resonance excitation in high-resolution tunneling spectra is reported. This resonance is observed along with higher harmonics, its frequency Ω/2Δ is anticorrelated with the local superconducting gap Δ, and its amplitude gradually vanishes by increasing the temperature and upon applying a magnetic field up to the critical values (TC and HC2 ), which sets an unambiguous link to the superconducting state. Aided by a microscopic model that captures the main experimental observations, this resonance is interpreted as a collective Leggett mode that represents the fluctuation toward a proximate f-wave triplet state, due to subleading attraction in the triplet channel. These findings demonstrate the fundamental role of correlations in superconducting 2D transition metal dichalcogenides, opening a path toward unconventional superconductivity in simple, scalable, and transferable 2D superconductors.