Patent ID: 7064820

Claim:
A surface inspection method in a surface inspection system which comprises a projection optical system for projecting two or more inspection lights at different incident angles to a substrate surface, a photodetection unit for detecting the inspection lights reflected from said substrate surface, and for detecting scattered reflected inspection lights, said photodetection unit comprising a photodetection polarizing angle changing means for changing a photodetection polarizing angle of said photodetection unit, comprising: a step of obtaining a signal component in a photodetection signal based on photodetection results when inspection lights are projected by changing incident angles, step of receiving a scattered reflection light from said substrate surface where standard particles are coated by changing a photodetection polarizing angle by said photodetection polarizing angle changing means, a step of obtaining the highest value of an S/N, signal to noise, ratio of photodetection output when the minimal value and the maximal value in a histogram are clearly separated from each other, and a step of performing surface inspection by setting the photodetection polarizing angle to a condition where the S/N ratio of photodetection output is at the highest.