Measuring method and its apparatus

A method for measuring a dimension of a pattern, comprising the steps of:

• creating an image profile of a pattern whose dimension is to be measured from a secondary electron image of a sample, the secondary electron image being obtained by picking up an image of the sample using a scanning electron microscope;
• obtaining a model profile that matches best with the image profile from a database that stores a plurality of model profiles that are obtained respectively from secondary electron images of cross sections of a plurality of patterns, the cross sections being of known dimensions and being different in shape;
• specifying a location for dimension measurement on a cross-sectional profile of the pattern whose cross-section corresponding to the obtained model profile is of a known dimension;
• estimating a cross-sectional shape of the pattern from information of the obtained model profiles;
• obtaining a dimension of a desired location of the pattern by using information of the estimated cross-sectional shape of the pattern;
• and
• displaying the obtained dimension of the desired location, the obtained model profile, the image profile, and the secondary electron image of the pattern, on a same screen.

An apparatus for measuring a dimension of a pattern, comprising:

• scanning electron microscope means for obtaining a secondary electron image of a sample by irradiating an electron beam converged on a specimen formed on the sample and allowing the electron beam to scan using a secondary electron image obtained by picking up an image of the sample using a scanning electron microscope;
• image profile creation means for creating an image profile of a pattern whose dimension is to be measured within the secondary electron image obtained by the scanning electron microscope means using the secondary electron image;
• storage means for storing a plurality of model profiles that are obtained respectively from secondary electron images of a plurality of patterns which are different in shape, and in which each of shapes and dimensions of cross sections of the plurality of patterns are known;
• model profile retrieving means for retrieving a model profile that matches best with the image profile created by the image profile creation means from the plurality of model profiles stored in the storage means;
• cross-sectional shape estimating means for estimating a cross-sectional shape of the pattern from information of the retrieved model profiles;
• and
• dimension calculation means for obtaining a dimension of the pattern using information of the estimated cross-sectional shape of the pattern.