Patent ID: 7977632

Claim:
A scanning electron microscope, comprising: an electron source; a deflector for scanning an electron beam emitted from said electron source, a detector for detecting electrons generated from a sample, and a negative voltage adding source for adding a negative voltage on said sample; said scanning electron microscope comprising the steps of: controlling said negative voltage so that a first irradiation energy has a secondary electron generation efficiency δ higher than 1.0, said secondary electron generation efficiency δ being defined by (secondary electron amount generated from substance forming a surface of said sample)/(primary electron amount irradiated to said substance), and after charging an insulation area including said contact hole into positive by scanning said sample with said electron beam having first irradiation energy, controlling said negative voltage so that said secondary electron generation efficiency δ of a second irradiation energy of the electron beam is closer to 1.0 than that of said electron beam having said first irradiation energy.