| 摘要 |
PROBLEM TO BE SOLVED: To obtain a defect inspection device that suppresses an influence of surface roughness of a specimen surface or scattered light from a normal circuit pattern, and can detect a defect and the like of the specimen surface with high sensitivity by increasing a gain of the scattered light from the defect or a foreign substance.SOLUTION: When a lens with a large NA value is used, a lens outer diameter is 10a, and an angle formed between an oblique optical system and a wafer is α1. When an elevation angle of the oblique detection optical system is made small for detecting much defect scattered light by reducing wafer surface roughness or surface roughness beneath an oxide film and scattered light from the circuit pattern, the elevation angle is α2<α1, but an outer diameter 10b of the lens is smaller than the lens outer diameter 10a, and a light converging ability of the scattered light is decreased. When a lens diameter is enlarged to 10c for increasing the light converging ability, the lens and a wafer 7 cause interference with each other. By creating a lens having an interference part eliminated, an aperture size of the lens can be made larger than the outer diameter 10b while the small elevation angle α2 is maintained, and thus, an improvement of a defect detection ability and an improvement of a lens performance can be simultaneously realized. |
