Particle-detection on glass substrates and thin film magnetic storage disks

A new device suitable for the detection of defects down to the submicrometer regime on both low- and high-reflectivity surfaces is presented. The major components of the system are a laser beam, which is focused onto the surface to be tested, a rotational and a linear state, which allow scanning of the sample, and a rotational ellipsoid, which focuses the light scattered from the sample onto the detector. Results obtained from blank glass substrates, highly reflective metal surfaces, and carbon protective layers are presented. Data that prove that the system is also suitable for an indirect quality control of liquid process media, which are required for cleaning, and lubrication, are given