Patent ID: 7348585

Claim:
A surface inspection apparatus, comprising: an optical system including an irradiation optical unit and a light-receiving optical unit; said irradiation optical unit being adapted for irradiating irradiation light emitted from a light source onto a surface of an object to be inspected and said light-receiving optical unit being adapted for receiving scattered light of the irradiation light reflected from the surface of said object; a displacement mechanism for displacing a position to be irradiated and detected by said optical system on the surface of said object relative to said optical system; a recording unit for detecting a state of the surface of said object based on a result of light-receiving of said optical system and recording the irradiated and detected position on the surface of said object as a plane-coordinate-position; a detector for detecting an amount of deviation of said plane-coordinate-position in a height direction relative to a reference height position; a first processor for correcting the plane-coordinate-position as said irradiated and detected position based on the deviation amount detected by said detector and thereby obtaining said corrected plane-coordinate-position; said irradiation optical unit comprises a multibeam irradiation optical unit for converging and irradiating multiple beams of which optical axes of irradiation are mutually parallel upon the surface of said object; said detector comprises a light-condensing optical unit including light-sensitive elements which have mutually parallel light-receiving axes and which are adapted for respectively receiving said multiple beams reflected by the surface of said object; and a second processor which analyzes information on said state of the surface as to whether the surface has a rough surface based on the results of receiving of said multiple beams, which obtains the plane-coordinate-position of said irradiated and detected position at the reference height position based on a difference between light-receiving reference positions of each of said light-sensitive elements when assumed that the irradiated and detected position of said object is at the reference height position and actual light-receiving positions of each of said light-sensitive elements, according to a result of the analysis of the surface state information, and which causes the first processor to correct the plane-coordinate-position.