Defect inspection method and device therefor

摘要

To process a signal from a plurality of detectors without being affected by a variation in the height of a substrate, and to detect more minute defects on the substrate, a defect inspection device is provided with a photoelectric converter having a plurality of rows of optical sensor arrays in each of first and second light-collecting/detecting unit and a processing unit for processing a detection signal from the first and the second light-collecting/detecting unit to determine the extent to which the positions of the focal points of the first and the second light-collecting/detecting unit are misaligned with respect to the surface of a test specimen, and processing the detection signal to correct a misalignment between the first and the second light-collecting/detecting unit, and the corrected detection signal outputted from the first and the second light-collecting/detecting unit are combined together to detect the defects on the test specimen.

主权项

1. A defect inspection device, comprising:
a stage unit which is movable at least in one direction with a test specimen placed thereon; a light irradiation unit which irradiates the test specimen placed on the stage unit with linearly shaped light from a direction inclined relative to a normal direction of a surface of the stage on which the test specimen is placed; a first light collecting/detecting unit which collects and detects light reflected/scattered in a first direction from the test specimen irradiated with the linearly shaped light by the light irradiation unit; a second light collecting/detecting unit which collects and detects light reflected/scattered in a second direction from the test specimen irradiated with the linearly shaped light by the light irradiation unit; a processing unit which processes a detection signal output from the first light collecting/detecting unit and a detection signal output from the second light collecting/detecting unit to detect a defect on the test specimen; and a control unit which controls the stage unit, the light irradiation unit, the first light collecting/detecting unit, the second light collecting/detecting unit and the processing unit, wherein each of the first light collecting/detecting unit and the second light collecting/detecting unit has a photoelectric converter provided with a plurality of optical sensor arrays, and the processing unit obtains misalignment of a focal position of the first light collecting/detecting unit relative to a surface of the test specimen by using detection signals from the plurality of optical sensor arrays of the first light collecting/detecting unit, obtains misalignment of a focal position of the second light collecting/detecting unit relative to the surface of the test specimen by using detection signals from the plurality of optical sensor arrays of the second light collecting/detecting unit, corrects the detection signal output from the first light collecting/detecting unit and the detection signal output from the second light collecting/detecting unit in accordance with the obtained misalignment of the focal position of the first light collecting/detecting unit and the obtained misalignment of the focal position of the second light collecting/detecting unit, combines together the detection signal output from the first light collecting/detecting unit and the detection signal output from the second light collecting/detecting unit which have been corrected to detect the defect on the test specimen.