Scanning electron microscope

A scanning electron microscope for producing a scanning image of a specimen by scanning a primary electron beam emitted from an electron source on said specimen, comprising:

• electric and magnetic fields separating trajectories of backscattered electrons and secondary electrons from said specimen which are established between said electron source and said objective lens;
• a backscattered electron detector detecting backscattered electrons generated from said specimen which is disposed on a trajectory of the backscattered electrons;
• and
• a secondary electron detector detecting said secondary electrons which is disposed on said trajectory of said separated secondary electrons;
• wherein detected signals from said backscattered electron detector and said secondary electron detector are added to each other or subtracted from each other to construct an image of said specimen.

A scanning electron microscope for producing a scanning image of a specimen by scanning a primary electron beam emitted from an electron source on said specimen by converging with an objective lens, comprising:

• electric and magnetic fields separating trajectories of backscattered electrons and secondary electrons generated from said specimen which are established between said electron source and said objective lens;
• an electrode capable of converting the backscattered electrons into secondary electrons and disposed at a position viewing the trajectory of the backscattered electrons;
• a secondary electron detector detecting the secondary electrons connected from the backscattered electrons at the electrode;
• and
• means capable of applying positive or negative voltage to said electrode capable of converting the backscattered electrons into secondary electrons.

A scanning electron microscope for producing a scanning image of a specimen by scanning a primary electron beam emitted from an electron source on said specimen by converging with an objective lens, comprising:

• electric and magnetic fields separating trajectories of backscattered electrons and secondary electrons generated from said specimen which are established between said electron source and said objective lens;
• a backscattered electron detector detecting the backscattered electrons which is disposed on the trajectory of the backscattered electrons to detect backscattered electrons generated from said specimen;
• a porous electrode constructed of an electrode through which electrons can transmit;
• an opposing electrode which opposes said porous electrode to generate the electric field, wherein said porous electrode and said opposing electrode are provided on a side of said electron source as viewed from said specimen;
• a magnetic field generating coil capable of generating the magnetic field, wherein the magnetic field is orthogonal, on the optical axis, to the electric field generated by said porous electrode and opposing electrode, thereby establishing the electric and magnetic fields separating the trajectories of the backscattered and secondary electrons;
• and
• means for controlling the exciting current lb of said magnetic field generating coil and the voltage +Ve applied to said electrodes such that the relations ##EQU4## are maintained, where the potential difference between said porous electrode and opposing electrode is .+-.Ve (V), the exciting current of said magnetic field generating coil is lb (A), the accelerating voltage for the primary electron beam is Vacc (V), constants determined by the shape of said porous electrode, opposing electrode and magnetic field generating coil are Ke and Kb, and for conditioning and setting the proportional constants K1 and K2 such that the electric and magnetic fields do not exert deflection action on the primary electron beam.