Development of Phase-retrieval measuring System for 3D Micromachined Surface Profile Measurement

Abstract

In this paper, we propose an optical measurement method that can be applied to the in-process measurement of microsurface profile with an accuracy on the nanometer order. Surface profiles are reconstructed by measuring two intensity distributions. Fraunhofer diffraction pattern of coherently illuminated work surface and an optical microscopic image. In this method, the whole illuminated profile can be measured at one time and no scanning procedure is imposed, and measurement is not likely to be affected by vibration and tilt of work. For higher resolution, the new instrument is designed and developed, and measurements of Fraunhofer diffraction including higher order diffraction intensities for an ultra precision grid plate standard is presented.