Measurement of ultra fine particles on the Si wafer surface using a laser light scattering method

摘要

This paper describes a system used for detecting the impurity particles on a bare Si wafer surface in a short time, at a wide area, and with a high reliability. The particles are less than 100nm in diameter. The wafer is illuminated with CW Ar-ion laser beam(diameter: 100μm, power: 600mW) at an oblique incident angle. The laser beam scattered by the particles is collected and focused at the direction perpendicular to the wafer surface. In order to achieve a uniform illumination in the whole observation area, the laser beam is scanned over the area.