Defect inspection system

Abstract

A defect inspection system can suppress an effect of light from a sample rough surface or a regular circuit pattern and increasing a gain of light from a defect such as a foreign material to detect the defect on the sample surface with high sensitivity. When a lens with a large NA value is used, the outer diameter of the lens is, and an angle between the sample surface and a traveling direction of the light from a defect is α. An oblique detection optics system receives the light from the defect at a reduced elevation angle αwith respect to the sample surface to reduce light from the sample rough surface, an oxide film rough bottom surface, and a circuit pattern, and to increase the amount of the light from the defect and detected. The diameterof a lens is smaller than the diameter, resulting in a reduction in the ability to focus the scattered light. When a lens with an outer diameteris used to improve the focus ability, the lens interferes with the sample. To avoid the interference, a portion of the lens interfering with the sample is removed. The lens has an aperture larger than the diameterwhile the lens receives the light scattered at the elevation angle α, making it possible to improve the ability to detect defects and lens performance simultaneously.