Low voltage scanning electron microscope and method for specimen observation

A specimen observation method, applied to the low voltage scanning electron microscope system, wherein the method comprises:

• accelerating, by an electron beam accelerator, an electron beam generated by an electron source;
• converging, by the compound objective lens, the electron beam accelerated by the electron beam accelerator, wherein the compound objective lens comprises a magnetic lens and an electrostatic lens;
• decelerating, by the electrostatic lens, the converged electron beam;
• and
• deflecting, by the deflection device, the decelerated electron beam to impinge the electron beam on a specimen to generate secondary electrons and backscattered electrons;
• and
• changing moving directions of the secondary electrons and the backscattered electrons under an effect of the electrostatic lens and the control device, to be received by the detection device,
• wherein changing moving directions of the secondary electrons and the backscattered electrons under an effect of the electrostatic lens and the control device, to be received by the detection device comprises:
• controlling a potential V3 on a control electrode of the electrostatic lens to be larger than a potential on a second sub-detection device of the electrostatic lens and smaller than a potential V2 on a specimen stage of the electrostatic lens;
• receiving, by the first sub-detection device, the backscattered electrons whose emitted angle with respect to a surface of the specimen is greater than a first threshold and secondary electrons, under control of an electrostatic field and a magnetic field generated by the control device;
• and
• receiving, by the second sub-detection device, the backscattered electrons whose emitted angle with respect to the specimen surface is less than the first threshold.