METHOD FOR APPROXIMATING NUMBER OF PARTICLES ON PATTERNED REGION OF WAFER SURFACE AND PRECISE INSPECTING DEVICE FOR SURFACE

摘要

PURPOSE: To provide a method and an apparatus for determining the number of contaminant material particles in a patterned circuit region on a semiconductor wafer. CONSTITUTION: A diffraction grating pattern is formed in same mode simultaneously with formation of a reflection circuit pattern on a wafer 10. The wafer is scanned by means of a laser beam 23 and since a diffraction pattern to be generated by a grating pattern is known, it can be detected when and which grating pattern is being scanned by the light beam. Scattering light from a non-grating region is separated spatially from the diffracted light from the grating and only the light scattered from a particle or a defect existing in the grating region is collected and detected by a photodetector 44. Number of particles in the grating region is calculated from a detected scattering light and the number of particles in the circuit pattern region is estimated by extrapolation. Alternatively, a stripped region may be inspected precisely.