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Xeiqing Zhu

Bio: Xeiqing Zhu is an academic researcher. The author has contributed to research in topics: Plasmon & Inelastic scattering. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the electron energy loss spectra (EELS) is described by an analytical function of the membrane thickness and the material characteristics, and a straightforward procedure using the analytical approximation of EELS and the results obtained from it for the SCALPEL mask-membrane in terms of chromatic aberration evaluation and control are presented.

2 citations


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TL;DR: In this paper, a detailed model of resist requirements, including sensitivity, etch selectivity, environmental stability, outgassing, and line-edge roughness as they pertain to, highvoltage (100 kV) direct write and projection electron-beam exposure systems are described.
Abstract: Electron beam lithography still represents the most effective way to pattern materials at the nanoscale, especially in the case of structures, which are not indefinitely repeating a simple motif. The success of e-beam lithography depends on the availability of suitable resists. There is a substantial variety of resist materials, from PMMA to calixarenes, to choose from to achieve high resolution in electron-beam lithography. However, these materials suffer from the limitation of poor sensitivity and poor contrast. In both direct-write and projection e-beam systems the maximum beam current for a given resolution is limited by space-charge effects. In order to make the most efficient use of the available current, the resist must be as sensitive as possible. This leads, naturally, to the use of chemically amplified (CA) systems. Unfortunately, in the quest for ever smaller feature sizes and higher throughputs, even chemically amplified materials are limited: ultimately, sensitivity and resolution are not independent. Current resists already operate in the regime of < 1 electron/nm2. In this situation detailed models are the only way to understand material performance and limits. Resist requirements, including sensitivity, etch selectivity, environmental stability, outgassing, and line-edge roughness as they pertain to, high-voltage (100 kV) direct write and projection electron-beam exposure systems are described. Experimental results obtained on CA resists in the SCALPEL® exposure system are presented and the fundamental sensitivity limits of CA and conventional materials in terms of shot-noise and resolution limits in terms of electron-beam solid interactions are discussed.

24 citations

Journal ArticleDOI
TL;DR: In this article, the effect of electron energy loss induced by inelastic scattering was quantified from the measured beam edge profiles considering lens aberrations and measurement errors using the knife-edge method, which can measure the image blur with the repeatability of 3 nm (3 sigma).
Abstract: In this article, we present experimental results that quantify the magnitude of chromatic aberrations induced by a SiNx continuous membrane mask. We used a continuous membrane mask, which consists of a TaSi scatterer layer on a SiNx membrane layer of 100 nm thickness, for the experiments. The beam edge profiles were measured directly by the knife-edge method, which can measure the image blur with the repeatability of 3 nm (3 sigma). The effect of electron energy loss induced by inelastic scattering is clearly shown in the measured beam edge profiles. The magnitude of chromatic aberrations is quantified from the measured beam edge profiles considering lens aberrations and measurement errors. The results show that lower atomic number Z and lower density materials and thinner membrane are required on the mask membrane for a high resolution lithography.

1 citations