Scanning electron microscope

A method for measuring patterns formed on a semiconductor wafer with a scanning electron microscope comprising steps of;

• scanning an electron beam on a plurality of measuring positions containing patterns,
• detecting secondary electrons emitted from the semiconductor wafer,
• determining, at each measuring position, a number of patterns or an evaluation value of the patterns based on an image of the pattern formed by the detected electrons, and
• skipping a next measuring position when it is determined that a shape of the patterns at the measurement position is getting worse than the patterns at previous measuring position.

A computer for controlling a scanning electron microscope comprising an electron gun, a deflector for scanning an electron beam on a sample, and a detector for detecting electrons generated from the sample by scanning the electron beam on the sample;

• the computer programmed to perform a sequence of steps comprising:
• scanning an electron beam on the patterns,
• detecting secondary electrons emitted from the semiconductor wafer,
• determining a number of patterns or an evaluation value of the patterns based on an image of the patterns formed by the detected electrons, and
• determining whether the patterns are to be measured or not, based on the number of parts or the evaluation value of the patterns.

A computer for controlling a scanning electron microscope comprising an electron gun, a deflector for scanning an electron beam in a sample on a sample, and a detector for detecting electrons generated from a sample by scanning the electron beam on the sample;

• the computer programmed to perform a sequence of steps comprising:
• scanning an electron beam on a plurality of measuring positions containing patterns,
• detecting secondary electrons emitted from the semiconductor wafer,
• determining, at each measuring position, a number of patterns or an evaluation value of the patterns based on an image of the patterns formed by the detected electrons, and
• skipping a next measuring position when it is determined that a shape of the patterns at the measurement position is getting worse than the patterns at previous measuring position.