Phenomenon of resist debris formation in electron beam lithography and its possible application
TL;DR: In this paper, the phenomenon of resist debris (RD) formation in electron beam lithography (EBL) under various conditions of proximity exposure (PE) effect is discussed and the PE correction at the preferred resist plane together with adequate beam to beam spacing can provide stable and uniformly distributed RD over the exposed pattern area.
About: This article is published in Vacuum.The article was published on 1996-11-01. It has received 1 citations till now. The article focuses on the topics: Proximity effect (electron beam lithography) & Electron-beam lithography.
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13 Sep 1974
TL;DR: In this article, the authors describe the computer program used in the Monte Carlo calculations of energy dissipation in a thin polymer film by electron beam scattering and provide a short user's manual and a listing of the computer programs.
Abstract: : This note describes the computer program used in the Monte Carlo calculations of energy dissipation in a thin polymer film by electron beam scattering. The results of those calculations have been presented elsewhere. The purpose of the present work is to provide a short user's manual and a listing of the computer program. (Author)
8 citations
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TL;DR: In this article, a simple technique for the computation of the proximity effect in electron-beam lithography is presented, which gives results of the exposure intensity received at any given point in a pattern area using a reciprocity principle.
Abstract: A simple technique for the computation of the proximity effect in electron‐beam lithography is presented. The calculations give results of the exposure intensity received at any given point in a pattern area using a reciprocity principle. Good agreement between the computed results and experimental data was achieved.
459 citations
TL;DR: The properties of polymethyl methacrylate resist, a new electron resist developed at IBM Research, are compared in comparison to commercial photoresists under electron beam exposure as discussed by the authors.
Abstract: The properties of poly‐(methyl methacrylate), a new electron resist developed at IBM Research, are presented in comparison to commercial photoresists under electron beam exposure. It is shown that methacrylate resist, with suitable processing, presents a means for submicron device fabrication with reasonable speed. Transistors with one‐ and half‐micron emitter stripe widths have been fabricated using this resist as a medium for diffusion masking with . Also, a method for producing high‐resolution, defect‐free masks through methacrylate resist is presented.
215 citations
TL;DR: In this article, Monte Carlo calculations have been performed to determine the spatial distribution of energy dissipated in a 4000-A-thick film of polymethyl methacrylate (PMMA), due to an incident electron beam.
Abstract: Monte Carlo calculations have been performed to determine the spatial distribution of energy dissipated in a 4000‐A‐thick film of polymethyl methacrylate (PMMA), due to an incident electron beam. The calculations were performed for 5‐, 10‐, and 20‐keV electrons on a silicon substrate and also for 20‐keV electrons on copper and gold substrates. The effect of varying the beam diameter from 250 to 3000 A was evaluated. A detailed comparison is made between the Monte Carlo results and analytic models used to predict the energy dissipated. The plural scattering model is found to be in good agreement with the Monte Carlo calculations, whereas discrepancies are found with the multiple scattering model. The large‐angle backscattering model is found to have several important limitations. Energy dissipation is calculated for the exposure of dots, isolated lines, and arrays of closely spaced lines—geometries that are of significance in electron beam lithography.
144 citations
TL;DR: In this paper, the solubility rate of polymethyl methacrylate electron resist for developer combinations of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) was determined in terms of the fragmented molecular weight which is a function of original molecular weight and the energy absorbed by the polymer in degrading to a lower molecular weight.
Abstract: We report on the solubility characteristics of poly‐(methyl methacrylate) electron‐resist for developer combinations of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA). The solubility rate is determined in terms of the fragmented molecular weight which is a function of original molecular weight and the energy absorbed by the polymer in degrading to a lower molecular weight. An empirical formula for the solubility rate is , where is the fragmented molecular weight, , β, and α are constants characteristic of a given developer. The temperature dependence is characterized by an activation energy, , for a given developer. The solubility kinetics are discussed showing a rate limited process for most developer conditions. From the solubility rate and the characteristic energy absorption in the resist, the development time and contrast are defined and calculated for a variety of exposure parameters including beam energy, resist thickness, developer, developer temperature, and original molecular weight. Compared to the standard developer, 1:3 MIBK:IPA, an improved sensitivity of 10–50 times is obtained using MIBK at the expense of increased development time. For a given contrast level the development time is greatly reduced by increasing the developer temperature. A lower original molecular weight also reduces the required development time.
135 citations
TL;DR: In this article, a mathematical model for the exposure of electron-sensitive resists where an electron beam is incident normal to a substrate coated with a thin layer of resist is presented, and the resulting contours predict the undercutting effect experimentally observed for the 5-20-keV beam energies studied.
Abstract: We present a mathematical model for the exposure of electron-sensitive resists where an electron beam is incident normal to a substrate coated with a thin layer of resist. We include both the scattering of the incident electrons as they penetrate the resist and the electrons backscattered from within the resist and from the substrate. The calculations yield contours of equal absorbed energy density, and these are interpreted as the contours which bound the resist after development. The absorbed energy density is found as the sum, for all electrons, of the product of the energy absorbed per unit length of trajectory and the flux density of electrons at the point in question. We first calculate the absorbed energy density for an electron beam of vanishingly small cross section (an incident delta function) and then convolve that result with a beam of Gaussian current-density distribution to obtain the reSult for a single beam location. For poly(methyl methacrylate) resist, we study the achievable dot resolution, as a function of the incident charge, for various incident energies-and substrates. Since our main interest is in computer-controlled resist exposures in which patterns are generated as a succession of dots, we calculate the absorbed energy density contours for a line generated in that manner. Detailed comparison is made with the experimental results of Wolf et al., by fitting a single point on one contour at one beam energy to account for the unknown developer sensitivity. The resulting contours predict the undercutting effect experimentally observed for the 5-20-keV beam energies studied. The developed shape and linewidth are found to be nonlinear functions of the incident charge per unit length. Experimental data for the linewidth at 20 keV are presented and compared with theory.
69 citations