Method And Apparatus For Detecting Defects

Abstract

A defect inspection method and apparatus that can easily and quickly determine, from among a plurality of inspection conditions, a condition that allows for an inspection with high sensitivity. The inspection apparatus has a variety of optical functions to cover a variety of kinds of defects to be inspected (shape, material, nearby pattern, etc.). For each optical function, grayscale depths of defects that the operator wants detected and of pseudo defects that he or she wants undetected are accumulated for future use, so that conditions conducive to a higher sensitivity and a lower pseudo defect detection rate can be selected efficiently. Conditions that can be selected for optical systems include a bright-field illumination, a dark-field illumination and a bright-/dark-field composite illumination, illumination wavelength bands, polarization filters and spatial filters.

1 . A defect inspection apparatus comprising:
 a light source means for emitting beams of a plurality of wavelength bands;   a light radiation means for selecting a beam of a desired wavelength from among the beams of the plurality of wavelength bands emitted by the light source means and radiating the selected beam onto a specimen formed with a wire pattern;   a detection means for receiving an optical image of the specimen, radiated with the beam of the desired wavelength from the light radiation means and formed with the wire pattern, and for outputting an image signal;   an image processing means for processing the image signal output from the detection means to detect defects;   a control means for controlling at least one of the light source means, the light radiation means, the image detection means and the image processing means;   an inspection information database means having a database associated with the specimen and a database associated with optical conditions of at least one of the light source means, the light radiation means, the image detection means and the image processing means; and   an input means for inputting information associated with the specimen;   wherein the light radiation means has a wavelength selection unit and a plurality of optical systems;   wherein the control means, based on information associated with a material of the wire pattern of the specimen input from the input means, controls the wavelength selection unit to select a beam of wavelength band to be radiated onto the specimen formed with the wire pattern, from among the beams of the plurality of wavelength bands emitted from the light source means and at the same time selects, from among the plurality of optical systems, an illumination optical system that corresponds to the beam of the selected wavelength band.   
   
   
       2 . A defect inspection method comprising the steps of:
 selecting a beam of a desired wavelength from among beams of a plurality of wavelength bands emitted from a light source and radiating the selected beam onto a specimen formed with a wire pattern;   photographing an optical image of the specimen formed with the wire pattern and radiated with the beam of the desired wavelength to obtain an image signal;   processing the obtained image signal to detect defects;   wherein in the step of selecting the beam of the desired wavelength and radiating the selected beam onto the specimen, according to information on a material of the wire pattern of the specimen, a desired wavelength band of the beam to be radiated onto the specimen and an illumination optical system corresponding to the beam of the desired wavelength band are selected and the selected beam of the desired wavelength band is radiated, through the corresponding illumination optical system, onto the specimen formed with the wire pattern.