Method and apparatus for measuring shape of a specimen

A method for measuring a shape of a semiconductor pattern on a semiconductor wafer in a scanning electron microscopy (SEM) apparatus including an electro-optical system to irradiate electron beams onto the semiconductor wafer, the method comprising the steps of:

• acquiring an image of the semiconductor pattern on the semiconductor wafer by observing the semiconductor pattern by scanning the electron beams onto the semiconductor wafer, via the electro-optical system;
• estimating a three-dimensional (3D) shape of the semiconductor pattern from the acquired image of the semiconductor pattern;
• segmenting an area for correcting the estimated 3D shape;
• determining a curve or a curved surface to be fitted to the acquired shape;
• and
• comparing the estimated shape with a control shape stored in advance and correcting the estimated 3D shape,
• wherein in the step of determining, the curve or curved surface is fitted to the estimated 3D shape of the semiconductor pattern within the area segmented at the step of segmenting;
• and
• wherein the estimated 3D shape is corrected by using the determined curve or curved surface by adjusting parameters of an equation of the determined curve or curved surface.

An apparatus for measuring a shape of a semiconductor pattern on a semiconductor wafer, comprising:

• SEM image acquiring means for acquiring tilt images of the semiconductor pattern on the semiconductor wafer;
• image processing means for processing the tilt images acquired by the SEM image acquiring means, for estimating a sectional three-dimensional (3D) shape of the semiconductor pattern from the tilt images of the semiconductor pattern, for calculating shape index values correlated with the estimated sectional 3D shape of the semiconductor pattern, for determining a range of a correction area in the estimated sectional 3D shape by segmenting an area of the estimated sectional 3D shape using information of the calculated shape index values, and for fitting a curve or a curved surface to a bottom corner of the estimated sectional 3D shape;
• shape correcting means for correcting the estimated sectional 3D shape of the semiconductor pattern within the determined range of the correction area based on the curve or curved surface fitted to the bottom corner of the estimated sectional 3D shape within the range of the correction area;
• and
• display means for displaying the corrected sectional 3D shape of the semiconductor pattern corrected by the shape correcting means.