Defect inspection apparatus and defect inspection method

Abstract

An apparatus and a method for defect inspection enables a reduction in the amount of noise light from an underlying layer and a good defect inspection reliably. The apparatus includes an illumination device that irradiates, with illumination light, a substrate to be inspected including a resist layer having cyclic patterns formed on the upper layer, and an optical image forming system that forms an image of the substrate to be inspected according to light that emerges from the substrate to be inspected by the irradiation with illumination light. The wavelength of the illumination light is set so that intensity of the light from the surface of the resist layer, among the light emerged from the substrate to be inspected, is greater than that of light that has passed through the surface of the cyclic pattern layer formed below the resist layer.

1 . A defect inspection apparatus comprising: 
 an illumination device that irradiates a substrate to be inspected with illumination light, the substrate to be inspected including a resist layer having cyclic patterns formed on an upper layer; and    an optical image forming system that forms an optical image of said substrate to be inspected according to light that emerges from said substrate to be inspected by the irradiation with said illumination light, wherein:    an antireflection layer is formed immediately below said resist layer; and    a wavelength of said illumination light is set in accordance with information on an absorption wavelength band of said antireflection layer.    
   
   
       2 . The defect inspection apparatus according to  claim 1 , wherein said information on the absorption wavelength band is an optical absorption spectrum of said antireflection layer.  
   
   
       3 . The defect inspection apparatus according to  claim 1 , further comprising: 
 a wavelength band input unit that inputs said information on the absorption wavelength band of said antireflection layer; and    a setting unit that sets the wavelength of said illumination light to a wavelength or a wavelength band included in the absorption wavelength band inputted from said wavelength band input unit.    
   
   
       4 . The defect inspection apparatus according to  claim 1 , wherein the wavelength of said illumination light is set to an exposure wavelength of exposure equipment which is used to form said cyclic patterns.  
   
   
       5 . The defect inspection apparatus according to  claim 1 , further comprising: 
 a sensitivity input unit that inputs information on sensitivity of said resist layer at the wavelength of said illumination light; and    a controller unit that aborts irradiating said substrate to be inspected with said illumination light when a dose of the illumination light reaches a limit dose which is determined in accordance with the sensitivity inputted from said sensitivity input unit.    
   
   
       6 . The defect inspection apparatus according to  claim 2 , further comprising: 
 a sensitivity input unit that inputs information on sensitivity of said resist layer at the wavelength of said illumination light; and    a controller unit that aborts irradiating said substrate to be inspected with said illumination light when a dose of the illumination light reaches a limit dose which is determined in accordance with the sensitivity inputted from said sensitivity input unit.    
   
   
       7 . The defect inspection apparatus according to  claim 3 , further comprising: 
 a sensitivity input unit that inputs information on sensitivity of said resist layer at the wavelength of said illumination light; and    a controller unit that aborts irradiating said substrate to be inspected with said illumination light when a dose of the illumination light reaches a limit dose which is determined in accordance with the sensitivity inputted from said sensitivity input unit.    
   
   
       8 . The defect inspection apparatus according to  claim 4 , further comprising: 
 a sensitivity input unit that inputs information on sensitivity of said resist layer at the wavelength of said illumination light; and    a controller unit that aborts irradiating said substrate to be inspected with said illumination light when a dose of the illumination light reaches a limit dose which is determined in accordance with the sensitivity inputted from said sensitivity input unit.    
   
   
       9 . A defect inspection method comprising the steps of: 
 irradiating a substrate to be inspected with illumination light, the substrate to be inspected including a resist layer having cyclic patterns formed on an upper layer;    generating an image of said substrate to be inspected by capturing an optical image according to light that emerges from said substrate to be inspected by the irradiation with said illumination light; and    detecting a defect in said cyclic patterns based on brightness information on the image of said substrate to be inspected, wherein    the wavelength of said illumination light is set in accordance with an optical absorption spectrum of said antireflection layer.    
   
   
       10 . The defect inspection method according to  claim 9 , further comprising the step of 
 setting a wavelength of said illumination light to an exposure wavelength of exposure equipment which is used to form said cyclic patterns.    
   
   
       11 . The defect inspection method according to  claim 9 , further comprising the step of 
 aborting irradiating said substrate to be inspected with said illumination light when a dose of said illumination light reaches a limit dose which is determined in accordance with the sensitivity of said resist layer at the wavelength of said illumination light.    
   
   
       12 . The defect inspection method according to  claim 10 , further comprising the step of 
 aborting irradiating said substrate to be inspected with said illumination light when a dose of said illumination light reaches a limit dose which is determined in accordance with the sensitivity of said resist layer at the wavelength of said illumination light.