Scanning electron microscope

Claim 2

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; and a secondary electron detector detecting said secondary electrons, wherein the secondary electron detector is disposed on said trajectory of said separated secondary electrons.

Claim 3

A scanning electron microscope according to claim 1, wherein said backscattered electron detector is disposed at a site which deviates from a trajectory of the primary electron beam.

Claim 4

A scanning electron microscope according to claim 1, further comprising: 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; and 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.

Claim 5

A scanning electron microscope according to claim 3, further comprising: means for controlling the exciting current Ib of said magnetic field generating coil and the voltage ±Ve applied to said electrodes such that the relations ##EQU2## 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 Ib (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.

Claim 6

A scanning electron microscope according to claim 1, further comprising an electrode capable of converting the backscattered electrons into secondary electrons and disposed at a position viewing the trajectory of the backscattered electrons.

Claim 7

A scanning electron microscope according to claim 5, further comprising: means capable of applying positive or negative voltage to said electrode capable of converting the backscattered electrons into secondary electrons.

Claim 8

A scanning electron microscope according to claim 6, further comprising: an axis-symmetrical electrode which is disposed along the optical axis more closely to said specimen than said porous electrode and through which primary electrons can pass; and means capable of applying positive and negative voltages to said axis-symmetrical electrode.

Claim 9

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.

Claim 10

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.

Claim 11

A scanning electron microscope according to claim 8, wherein signals from said bacscattered electron detector and said secondary electron detector are displayed in different colors.

Claim 12

A scanning electron microscope for producing a scanning image of a specimen by focusing a primary electron beam emitted from an electron source by means of an objective lens and scanning it on said specimen, comprising: electric and magnetic fields for separating trajectories of backscattered electrons and secondary electrons generated from said specimen which are established between said specimen and electron source; and a backscattered electron detector for detecting the backscattered electrons which is disposed between said objective lens and electron source so that the distance between said specimen and said objective lens may be narrowed.

Claim 13

A scanning electron microscope for producing a scanning image of a specimen by focusing a primary electron beam emitted from an electron source by means of an objective lens and scanning it on said specimen, comprising: electric and magnetic fields for separating trajectories of backscattered electrons and secondary electrons generated from said specimen which are established between said specimen and electron source; and a backscattered electron detector for detecting the backscattered electrons which is disposed between said objective lens and electron source so that the distance between said specimen and said objective lens may be narrowed.

Claim 14

A scanning electron microscope according to claim 10, wherein said backscattered electron detector is disposed at a site which deviates from a trajectory of the primary electron beam.

Claim 15

A scanning electron microscope according to claim 10, further comprising a secondary electron detector detecting the secondary electrons which is disposed on the trajectory of the secondary electrons to detect secondary electrons generated from said specimen.

Claim 16

A scanning electron microscope according to claim 10, further comprising: 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; and 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 for separating the trajectories of the backscattered and secondary electrons.

Claim 17

A scanning electron microscope according to claim 13, further comprising: 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 ##EQU3## 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.

Claim 18

A scanning electron microscope according to claim 10, further comprising an electrode capable of converting the backscattered electrons into secondary electrons and disposed at a position viewing the trajectory of the backscattered electrons.

Claim 19

A scanning electron microscope according to claim 15, further comprising: means capable of applying positive or negative voltage to said electrode capable of converting the backscattered electrons into secondary electrons.

Claim 20

A scanning electron microscope according to claim 16, further comprising: an axis-symmetrical electrode which is disposed along the optical axis more closely to said specimen than said porous electrode and through which primary electrons can pass; and means capable of applying positive and negative voltages to said axis-symmetrical electrode.

Claim 21

A scanning electron microscope according to claim 10, further comprising: a secondary electron detector detecting the secondary electrons which is disposed on the trajectory of the secondary electrons, wherein signals from said backscattered electron detector and secondary electron detector are added to each other or subtracted from each other to construct said specimen image.

Claim 22

A scanning electron microscope according to claim 10, further comprising: a secondary electron detector detecting the secondary electrons which is disposed on the trajectory of the secondary electrons, wherein signals from said backscattered electron detector and said secondary electron detector are displayed in different colors.

Claim 23

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.

Claim 24

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.

Claim 25

A scanning electron microscope according to claim 20, further comprising: an axis-symmetrical electrode which is disposed along the optical axis more closely to said specimen than said porous electrode and through which primary electrons can pass; and means capable of applying positive and negative voltages to said axis-symmetrical electrode.

Claim 26

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.

Claim 27

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.