Method of inspecting a pattern and an apparatus thereof and a method of processing a specimen

A method of inspecting a pattern comprising the steps of:

• radiating and scanning an electron beam on an object to be inspected;
• detecting secondary charged particles generated from the pattern formed on said object to be Inspected by the radiating and scanning of said electron beam to obtain an image of the pattern according to the detected secondary charged particles;
• detecting an intensity of said image of the pattern of said object to be inspected;
• setting a threshold value depending on the detected intensity of said image;
• and
• detecting either a defect or a candidate for defect of the pattern by processing said image of the pattern using said set threshold value.

A method of inspecting a pattern comprising the steps of:

• radiating and scanning an electron beam to a first region on object to be inspected to obtain a first image of said first region based upon detection of generated secondary charged particles;
• radiating and scanning an electron beam to a second region on said object to be inspected to obtain a second image of said second region based upon detection of secondary charged particles;
• comparing said first image with said second image to obtain a difference image between said first and second images;
• detecting an intensity of at least one of said first and second images;
• and
• detecting either a defect or a candidate for defect of the pattern formed on said object to be inspected by processing said difference image by using a threshold value corresponding to the detected intensity of the at least one of said first and second images.

A method of inspecting a pattern comprising the steps of:

• radiating and scanning an electron beam to each of patterns designed to have a same shape which are formed on an object to be inspected;
• detecting secondary charged particles generated from each of said patterns by radiating and scanning to obtain each of images according to the detected secondary charged particles;
• obtaining a difference image of each of said obtained images;
• detecting a brightness of said obtained images;
• extracting a defect of the pattern formed on the object from said difference image by using a plurality of threshold values set up according to the detected brightness of said obtained images.

An apparatus for inspecting a pattern comprising:

• charged particles optical system means for radiating and scanning charged particle beam on object to be inspected to obtain a charged particles image of said object to be inspected, the charged particles optical system means further comprising:
• charged particle beam radiating/scanning section for radiating and scanning charged particle beam on said object to be inspected;
• a secondary charged particles image detecting section for detecting the secondary charged particles generated from said object to be inspected with charged particle beam radiated and scanned on said object to be inspected at said charged particle beam radiating/scanning section to obtain a secondary charged particles image;
• and
• a memory section for storing a charged particles image of first pattern originally formed to have a same shape on said object to be inspected which is detected at said secondary charged particles image detecting section, and a charged particles image of second pattern;
• and
• a defect detecting means for processing the charged particles image of said object to be inspected obtained by said charged particles optical system means and detecting a defect of pattern formed on said object to be inspected,
• the defect detecting means further comprising:
• a difference image producing section for producing a difference image between the charged particles image of the first pattern stored in the memory section of said charged particles optical system means and the charged particles image of said second pattern;
• a threshold value setting section for setting a threshold value depending on a level of signal of charged particles images of the first pattern and the second pattern;
• and
• a defect detecting section for processing said difference image by using the threshold value set at said threshold value setting section and detecting either a defect or a candidate for defect of the pattern formed on said object to be inspected.

An apparatus for inspecting a pattern comprising:

• image taking means for obtaining an image of a pattern of an object to be inspected by radiating and scanning an electron beam on the object to be Inspected;
• memory means for storing a reference image;
• difference image producing means for producing a difference image between the image of said pattern of the object to be inspected obtained by said image taking means and said reference image stored in said memory means;
• threshold value memory means for storing a plurality of threshold values of the difference images;
• intensity detection means for detecting an intensity of said image of said pattern of the object to be inspected which is obtained by said image taking means;
• threshold value setting means for setting a threshold value among said stored plurality of threshold values based upon the detected intensity of said image detected by said intensity detection means;
• and
• defect detecting means for detecting a defect of said pattern by evaluating the difference image produced by said difference image producing means by using the threshold value set by said threshold value setting means.

A method for processing a substrate, for forming a pattern in sequence through a plurality of processes, comprising the steps of;

• radiating and scanning an electron beam on a surface of a processed substrate processed by a predetermined process of a plurality of processes for processing the substrate to obtain an image of the surface of said processed substrate based upon detection of secondary charged particles;
• evaluating a dispersion of brightness of said image;
• and
• correcting said predetermined process by using said evaluated result.

A method for processing a substrate for forming a pattern in sequence through a plurality of processes, comprising the steps of:

• radiating and scanning an electron beam on the surface of the substrate processed by a predetermined process of said plurality of processes for processing the substrate to obtain an image of the surface of said processed substrate based upon detection of secondary charged particles;
• evaluating a dispersion of brightness of said image;
• and
• correcting processes subsequent to said predetermined process by using said evaluated result.

A method for processing a substrate, for forming a pattern in sequence through a plurality of processes, comprising the steps of:

• radiating and scanning an electron beam on a surface of a first substrate processed by a predetermined process in said plurality of processes to obtain a first charged particles image .of the surface of said first substrate;
• storing said first charged particles image;
• radiating and scanning an electron beam on a surface of a second substrate processed by said predetermined process to obtain a second charged particles image of the surface of said second substrate;
• comparing said second charged particles image with said stored first charged particles image to obtain a difference image therebetween;
• and
• correcting said predetermined process by using information obtained by processing said obtained difference image with a threshold value according to a noise component of said difference image.