Scanning electron microscope, method for measuring a dimension of a pattern using the same, and apparatus for correcting difference between scanning electron microscopes

A method for measuring a dimension of a pattern using a plurality of scanning electron microscopes (SEMs) comprising the steps of:

• designating a scanning electron microscope to serve as a reference SEM;
• designating a SEM to be calibrated;
• calculating a feature quantity of an image profile of a sample pattern, obtained by imaging the sample pattern with the reference SEM;
• calculating a feature quantity of an image profile of the sample pattern obtained by imaging the sample pattern with the SEM to be calibrated;
• finding a value of a parameter by which the calculated feature quantity of the image profile of the sample pattern obtained by imaging with the reference SEM is matched with the feature quantity of the image profile of the sample pattern obtained by imaging with the SEM to be calibrated;
• correcting the sample image obtained by imaging with the SEM to be calibrated, using the parameter value by which the corresponding feature quantities of the images obtained using the reference SEM and the SEM to be calibrated are matched;
• and
• finding the dimension of the sample pattern from the corrected sample image.

A plurality of scanning electron microscopes (SEMs) for measuring a dimension of a pattern,

• comprising:
• electron beam irradiation means for irradiating and scanning a converged electron beam on a sample on which a pattern is formed;
• image acquisition means for acquiring an image of the pattern formed on the sample by detecting secondary electrons emitted from the sample under the impact of the converged electron beam using one SEM;
• a memory for storing at least one filter parameter determined by matching corresponding feature quantities of at least one image profile obtained from the image of the pattern using the one SEM with the feature quantities of at least one image profile obtained using at least one other SEM different from the one SEM;
• image profile creation means that read the at least one filter parameter stored in the memory and create an image profile from both the at least one read filter parameter and an image of a pattern acquired by the image acquisition means;
• pattern dimensional measurement means for measuring a dimension of the pattern from the image profile created by the image profile creation means;
• and
• display means for displaying results measured by the pattern dimension measurement means.

An apparatus for correcting a difference among a plurality of scanning electron microscopes (SEMs) for measuring a dimension of a pattern,

• comprising:
• designation means for designating both a reference SEM and a SEM to be calibrated using the reference SEM;
• first memory for storing a feature quantity of an image profile of a sample pattern obtained by imaging the sample pattern with the reference SEM designated by the designation means,
• second memory for storing a feature quantity of an image profile of the sample pattern obtained by imaging the sample pattern with the SEM to be calibrated designated by the designation means,
• parameter calculation means for calculating a parameter to match the corresponding feature quantities of the image profiles of the sample pattern stored in the second memory with the feature quantities of the image profiles of the sample pattern stored in the first memory;
• image correction means for correcting an image of a specimen obtained by imaging with the SEM to be calibrated using the parameter for matching calculated by the parameter calculation means;
• and
• dimension measurement means for determining a dimension of the pattern on the specimen from the image of the specimen corrected by the image correction means.