Importance

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Abstract

An extraneous substance inspection apparatus for a patterned wafer, according to the present invention, comprises an optical sensor having a plurality of detecting portions arranged to receive the scattering light corresponding to pixels and produce the detection signal corresponding to the respective pixels, a delay circuit responsive to the detection signal from the optical sensor for delaying the detection signal by a predetermined time and a judging circuit for judging an absence or presence of contaminant by comparing an output of the delay circuit with the detection signal from said optical sensor, wherein the wafer is inclined by a predetermined angle with respect to a direction parallel to the arranging direction of the detecting portions of the optical sensor and the predetermined time corresponds to a difference in scan time between a position of one pixel and substantially the same position as that of the one pixel in one chip of another pixel in another chip adjacent to that chip, the another pixel being determined corresponding to the predetermined angle in the X-Y scanning.

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First Claim