Precise Measurements of Micro-linewidths by using a Micro-Interferometer and a Scanning Electron Microscope

Abstract

A small interferometer for the use of precise scanning electron microscopy has been developed. Optical components and a piezo-driven mechanical scanner are integrated on a small disk of 130mm in diameter. the device is small enough to be installed in the vacuum chamber of regular scanning electron microscopes (SEMs), and enables absolute linewidth niasurements based on laser wavelength. The performance of the system is evaluated and compared to those of an absolute linewidth measurement system we have developed before. The results show good agreement of a couple of nanometers in the sub-micrometer linewidth measurements. This system can be applied to various types of microscopes such as scanning probing microscopes (SPMs). and useful as an important device for calibration service in the precise micro-length measurement.