FLAT SUBSTRATE SURFACE STATE INSPECTION METHOD AND FLAT SUBSTRATE SURFACE STATE INSPECTION DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a flat substrate surface state inspection device capable of detecting extremely minute scratches and cracks that have not been detected in the past.SOLUTION: A flat substrate surface state inspection device comprises: at least two light projecting systems that expose a flat substrate surface side to a laser from a direction different from the surface at a prescribed incident angle with respect to a substrate normal; at least two light receiving systems that are provided on the surface side and are provided at positions opposite to the light projecting systems on the basis of an exposure point of the laser, so as to face the light projecting systems with one another; laser forming means that forms the laser so as to make a laser-exposed region on the flat substrate surface exposed to each laser rectangular; exposed region interval adjusting means that adjusts each light projecting system and each light receiving system so that each interval between rectangular-shaped laser-exposed regions is equal to projection length in a scanning direction of the rectangular shape or to non-overlapping length meaning the length preventing the laser-exposed region from overlapping with one another; and feed pitch adjusting means that make adjustments so that a prescribed pitch for axial feed is equal to or more than the projection length or non-overlapping length or is equal to an integral multiple of the projection length or non-overlapping length.