Abstract
Most of the defects of the semi-conductor patterns are caused by the foreign particles on the wafers. We developed an automatic machine which detects the foreign particles (their diameters are larger than 2∼3μm) on a wafer, whether it has patterns or not. The pattern sizes are usually 3∼5μm wide, 1μm high.
We illuminate the small area on a wafer by means of the polarized laser obliquelly, and detect the light, which is scattered by the pattern or the foreign particle on the wafer, from right above the wafer. We can find the foreign particles only, by detecting the scattered light of which the angle of palarization is changed. By the use of this machine, we can know quantitatively the number of foreign particles in the making process of a small pattern like that on LSI.
