Patent ID: 7872743

Claim:
A defect inspection system for inspecting a defect in a sample, the system comprising: a stage on which the sample is moved; an illumination optical system for irradiating a surface of the sample with a testing illumination light beam having a predetermined incident angle with respect to the sample surface to generate a beam spot on the sample surface; an oblique detector including a first sensor having a first optical axis inclined with respect to the sample surface by a predetermined angle to detect light from the beam spot, and a sensor movement device which moves the first sensor; an upright detector including a second sensor having a second optical axis along the normal of the sample surface to detect light from the beam spot; and a signal processor including a processing controller to detect a defect on the sample using outputs from the oblique detector and the upright detector; wherein the processing controller controls the stage to move the sample in the second optical axis direction to adjust the focal length of the upright detector; and wherein the processing controller controls the sensor movement device according to the amount of movement of the sample to move the position of the first sensor in the oblique detector.