Patent ID: 8055057

Claim:
A method of detecting defects in a substrate, the method comprising: establishing a first inspection region including at least one first pattern repeatedly formed in a first direction on the substrate, the first inspection region including a portion of a cell block, and a second inspection region including at least one second pattern repeatedly formed in a second direction on the substrate, the second inspection region including a peripheral portion of the cell block, wherein a semiconductor device is mounted on the substrate; determining a first unit inspection size of the first inspection region, wherein the first unit inspection size functions as a first comparison unit if defects are detected; determining a second unit inspection size of the second inspection region, wherein the second unit inspection size functions as a second comparison unit if defects are detected; obtaining at least one image of the first pattern in the first inspection region and at least one image of the second pattern in the second inspection region by moving the substrate in the first direction, wherein the substrate faces an image receiving member; detecting defects in the first inspection region by comparing portions of the images obtained from the first inspection region with each other, wherein each of the portions has the first unit inspection size; and detecting defects in the second inspection region by comparing portions of the images obtained from the second inspection region with each other, wherein each of the portions has the second unit inspection size.