Real Time Nanoparticle Observation in Cleaning Phenomena by Evanescent Field

7th report : Measurement Distance of Nano-Particle from Surface by using Defocus outside the Evanescent Field

Abstract

Preventing the re-deposition of nano-particles on the substrate surface is essential in wafer cleaning. Although 3D measurement of the behavior of nano-particles that have been detached and moved by shear flow generated in the extreme vicinity of the surface (moving position) has been performed, it is necessary to use this method in combination with the dark-field observation method, which was limited to observation of suspended particles in very close proximity with surface-localized light. In this paper, we report on our attempt to utilize defocusing using cylindrical lenses to obtain sufficient longitudinal resolution for shallow and deep position measurement of moving particles.