Deposition of Charged Submicron Particles in Circular Tubes Made of Various Materials

概要

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Deposition of submicron particles in the manufacturing process of semiconductors is one of the main causes of reducing production yield. In order to suppress particle deposition onto the surface of various materials, the deposition mechanisms of submicron particles have to be well understood. In the present work, by using circular tubes made of various materials, deposition of particles in various charging states was experimentally investigated. The tube materials studied were copper, glass, polymethylmetacrylate (PMMA), polyvinylchloride (PVC), polycarbonate (PC), and polyethylene (PE). As a result it was found that 1) uncharged particle deposits by Brownian diffusion in all the tubes studied ; 2) charged particle deposits in PMMA, PVC, PC and PE tubes by Coulombic force, and that the dimensionless deposition velocity is equal to the Coulombic force parameter derived for charged particle and charged infinite flat surface. Furtller, from the measurement of time dependency of particle penetration, decay of triboelectric charge on PVC and PC tubes was found to obey the law of hyperbolic decay.