Patent ID: 6946654

Claim:
A scanning electron microscope system including an electron energy analyzer, comprising: a primary electron beam column for forming a primary electron beam and focusing it onto the specimen, the primary electron beam column including a high resolution objective lens that immerses the sample in a magnetic field; and a secondary electron optical system for collecting secondary electrons through the high resolution objective lens, the secondary electron system including: a lens creating an accelerating field for accelerating secondary electrons through the high resolution objective lens; an electrostatic capacitor for deflecting the secondary electrons from the path of the primary beam; a shield extending substantially through the electrostatic capacitor and shielding the primary beam from deflection and aberrations caused by the electrostatic capacitor, the shield being conductive on the inside to shield the primary beam and having on the outside a potential gradient to create an external electric field related to the electric field of the electrostatic capacitor, thereby reducing distortion of the field of the electrostatic capacitor caused by the shield; and an electron energy analyzer for determining the energy of the secondary electrons.