Mitsuyoshi Koizumi

Automatic Inspection Of Contaminants On Reticles

Wafer steppers require contaminant-free reticles to assure high yield. This paper describes a new particle detection technique. A linearly polarized He-Ne laser beam scans obliquely across the reticle surface and only scattering light produced by the particles is detected by the detectors, which consist of analyzers, collection lenses, slits, and PMTs (photomultipliers). On the other hand, scattering light produced by the pattern edges on the reticle is cut off by the analyzers. Using this technique, particles as small as 2 1im on the surface of pellicle-installed reticles can be detected.

Polarized Laser Scan Technique For Patterned Wafer Surface Contaminants Inspection

A new system for detecting contaminants on patterned Si wafers is described. The system employs a linearly polarized He-Ne laser light to scan obliquely across the wafer surfaces, and optical detection technique to distinguish the contaminants from the patterns by measuring the polarization of the light reflected from both the contaminants and the patterns.