CZ2013293A3 - Detection method of signal electrons in electron microscope and apparatus for making the same - Google Patents

Abstract

The present invention relates to a method for detecting signal electrons in an electron microscope. The emitted primary electron beam (1) and the emitted signal electron beam (6) are acted above the primary electron beam impact point (1) on the observed object (7) first, in the direction of emitted primary electrons, by the first homogeneous magnetic sector field whose the magnetic induction vector is perpendicular to the optical axis (3) of the system for deflecting the emitted primary electron beam (1) in one direction. Then it is treated by a second homogeneous magnetic sector field, whose magnetic induction vector is perpendicular to the optical axis (3) of the array and opposed to the magnetic induction vector of the first homogeneous magnetic sector array to bring the beam of emitted primary electrons and the beam of signal electrons opposite the optical axis (3) systems. Finally, it is treated by a third homogeneous magnetic sector field whose magnetic induction vector is perpendicular to the optical axis (3) of the array and parallel to the magnetic induction vector of the first homogeneous magnetic sector array to return the emitted primary electron beam (1) to the optical axis (3) and deflecting the signal electron beam (6) from the optical system axis (3) after emission from the primary electron beam (1) to the object (7). The signal electron beam (6) is then sensed in the region of the third or second homogeneous magnetic sector field, in which the signal electron beam (6) is deflected from the path of emitted primary electrons of the primary electron beam (1). The solution also applies to equipment for execution

Description

Technical field

The invention relates to a method for detecting signal electrons in an electron microscope and to an apparatus for carrying out the method.

BACKGROUND OF THE INVENTION

Scanning electron microscopy works with a wide range of primary electron energies that hit the specimen. This range is of the order of several tens of keV in the case of high-voltage electron microscopy, several eV units in the case of low-voltage electron microscopy, or electrons with zero energy in the case of mirror electron microscopy.

Mirror electron microscopy is still realized on the principle of emission electron microscopy with a separate illumination and imaging system, where the specimen is placed at the potential of the electron source, which is the cathode. It is a very demanding method of integral image processing.

Due to the increasingly used scanning electron microscopy, there is an effort to extend the possibilities of this method into the field of very low energies of electron impact on the specimen to the area of mirror imaging.

The standard scanning electron microscope arrangement for working with low electron impact energy also utilizes, as in the case of low-voltage electron microscopy, the placement of the specimen at the cathode potential. This approach is necessary because electron sources and systems are unable to work with low-energy electrons. To ensure the functionality of the electron optical system, it is necessary to work with electrons with energy of at least several units to V and to reduce the energy of the electron impact on the specimen, 'DJ202- /

26r3r20t3f

- As in low-voltage electron microscopy, placing the specimen at a potential close to or equal to the cathode potential.

The specimen placed at a certain potential then forms, together with the last electrode or pole piece of the objective lens, an additional electrostatic lens, also called a cathode immersion lens, in which the primary electrons are first retarded accordingly and accelerated again in the opposite direction after interaction with the specimen. If the specimen potential is very close to that of the cathode, the reflected electrons (BSE) as well as the emitted secondary electrons (SE) are centered closely around the optical axis of the microscope and return to the optical system following trajectories practically identical to the primary electron trajectories in the opposite direction. . Such accelerated secondary electrons cannot be detected by a rotationally symmetrical detector. The situation becomes even more complicated when the principle of magnetic open objective lens (magnetic immersion lens), whose magnetic field reaches to the surface of the specimen, is used to increase the resolution of the microscope. In addition, the secondary electrons are held by the magnetic field in close proximity to the optical axis and their separation from the primary electrons is in principle excluded in the rotationally symmetrical system. At a sufficiently large magnification, all the signal, including both reflected and secondary electrons, is fed back into the optical system by passing through the electrode or pole piece apertures back into the cathode space without being captured for imaging.

From US 6,841,776 a solution is known covering the problem of scanning electron microscopy in the first part of the patent, but it solves the separation of the illumination beam from the signal by means of Wien filters, which is a combination of magnetic and electrostatic elements. A disadvantage of this arrangement is that this combination of fields, in principle, compromises the quality of the illumination beam and thus deteriorates the attainable resolution parameter.

.-DJ202I, 2 * 3: 201 /

3. Summary of the Invention

The aforementioned drawbacks of the prior art are largely eliminated by a method of detecting signal electrons in an electron microscope wherein the essence of the invention is to treat the primary electron beam and the back-emitted signal electron beams above the primary electron beam spot on the observed object by three homogeneously arranged magnetic sector fields. First, in the path direction of the emitted primary electrons, a first homogeneous magnetic sector field is applied, whose magnetic induction vector is perpendicular to the electron beam to deflect the emitted primary electron beam in one direction. Thereafter, a second homogeneous magnetic sector field is applied, whose magnetic induction vector is perpendicular to the electron beam and opposed to the magnetic induction vector of the first homogeneous magnetic sector field to adhere the emitted primary electron beam and the signal electron beam opposite the axis of the optical system. Finally, a third homogeneous magnetic sector field is applied whose magnetic induction vector is perpendicular to the electron beam and parallel to the magnetic induction vector of the first homogeneous magnetic sector field to return the emitted primary electron beam to the optical axis of the array and deflect the signal electron beam from emission from the primary electron beam spot on the observed object. The signal electron beam is then sensed in the region of a third or second homogeneous magnetic sector field in which the signal electron beam is deviated from the path of the primary electron beam emitted.

In a preferred embodiment of the method, the signal electron beam is sensed in several regions of a third or second homogeneous magnetic sector field for separately sensing signal electrons with different energies.

2fr-3: 2013 /

03202- (

The aforementioned drawbacks of the prior art also largely eliminate the apparatus for carrying out the method according to the invention, which comprises in the upper pole piece of the electron microscope objective lens a set of magnetic prism arrays arranged one below the other in the direction of electron movement in the primary beam the first magnetic optical prism, the second magnetic optical prism and the third magnetic optical prism. A scanning system is arranged below these magnetic optical prisms. A detector for detecting signal electrons emitted from the specimen is then arranged outside the optical axis of the system. The detector may advantageously be a scintillator connected to the light guide.

In a preferred embodiment of the apparatus for performing a method for separately sensing different energy signal electrons, the apparatus comprises a set of magnetic optical prisms arranged in a shielding tube of an electron microscope and arranged one below the other in the direction of electron movement in the primary electron beam. an optical prism and a third magnetic optical prism. A scanning system is arranged below the system of magnetic optical prisms. Outside the optical axis of the system in several regions of the third and / or second magnetic optical prism, a composite electron detector is provided for separately sensing signal electrons with different energies.

In a particularly preferred embodiment of the device, an auxiliary magnetic optical prism is arranged in the region of the third and / or second magnetic optical prism to increase the deflection of the signal electron beam.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 schematically illustrates the principle of signal electron detection method in an electron microscope according to the invention; Figure 2 schematically illustrates an optical scheme of an optical magnetic prism system

26.3.20W

Figure 5 schematically shows the optical diagram of the system of Figure 2 in a non-dispersive plane; Figure 4 schematically shows the optical diagram of the split prism system in spectrally selective mode; Fig. 5 schematically shows an optical scheme of a split prism system in a non-selective energy mode; Fig. 6 schematically shows an optical scheme of a system of asymmetrically arranged optical prisms suitable for broadband energy non-selective detection; a system of asymmetrically arranged optical prisms suitable for sensing an energy spectrum or an integral signal, FIG. 8 shows schematically an apparatus for carrying out said method with magnetic deflection, and FIG. 9 schematically shows An apparatus for carrying out said method with electrostatic deflection.

ά '. · -aa - ·' λ · - and i

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, an axially unsymmetrical method of detecting both secondary and reflected electrons can be used for signal detection for image generation in the case of very low or zero energies of the scanning beam impact on the specimen. Magnetic sector fields or magnetic prisms are used to separate the primary or illumination electron beam in a scanning electron microscope so that the recurrent signal electrons, both secondary and reflected, are deflected from the optical axis of the instrument without significant influence on trajectories of primary electrons. This requirement is particularly necessary for the realization of mirror scanning electron microscopy, but is able to cover a wide energy spectrum of incident electrons in an arrangement where an electrical preload is applicable to the specimen.

Generally, a homogeneous magnetic field acting on moving electrically charged particles, i.e. electrons or ions, rotates their motion along circular trajectories in a plane perpendicular to the acting magnetic field, the direction of rotation being dependent on the relative orientation of the direction of motion of the charged particle, direction effect of magnetic field and charge polarity.

It follows that an arrangement of optical magnetic prisms is possible that is capable of separating the electron beam in one direction from one another on the specimen incident from the electron beam leaving the specimen in the opposite direction.

However, the basic requirement is that the quality of the beam incident on the specimen is not impaired so that the resolution of the scanning electron microscope is not lost and, on the other hand, the deflection of the signal electron trajectories is sufficiently large for the technical feasibility of their detection.

It is apparent from the properties of magnetic sector fields or optical prisms that, in the trajectory twisting plane, the prism has a certain optical power and is able, for example, to focus parallel beams in the form of a linear focal point parallel to the magnetic field. Focusing in a direction perpendicular to this can also be achieved by varying the angle of incidence of the electron beam on the leading edge of the magnetic prism. It can be shown that by suitable selection of the parameters of the magnetic prism it is possible to achieve stigmatic point-to-point imaging.

Another property of optical magnetic prisms is their energy dispersion. This means, for example, that electrons of different energies have different trajectories in the transverse magnetic fields and it is thus possible to differentiate electrons according to their energy. On the other hand, it is possible to find an arrangement of the optical magnetic prism system in which the energy dispersion is suppressed.

Application of a special arrangement of optical magnetic prisms on the optical axis of the scanning electron microscope

D3202 /

2 & 3 ·; 201, it is possible to achieve mutual separation of primary, i.e., illumination, and re-emitted, i.e. signal, electrons, so that detection of these electrons outside the optical axis of the system is possible. This principle is schematically illustrated in FIG. 1. The primary electron beam 1 enters the first optical magnetic prism 2, which deflects it away from the optical axis 3 of the assembly. The deflected primary electron beam 1 enters the second optical magnetic prism 4, which deflects it in the opposite direction, i.e. again deflects it to the optical axis 3 of the assembly. The primary electron beam 1 enters the third optical magnetic prism 5, which deflects it in the opposite direction, i.e. again deflects it away from the optical axis 3 of the system so as to coincide with the optical axis 3 of the system. The primary electron beam 1 excites on the observed object 7 the signal electron beam 6 of secondary or reflected electrons, which enters the optical system in the opposite direction to the primary electron beam 1. If the rotating direction of both the primary and signal electrons depends on the orientation of the charged particle effect of magnetic field and charge polarity, then it is clear that since the polarity of charges of both primary and signal electrons and the direction of magnetic field action are identical, it will be the direction of motion of the charged particle opposite to the signal electrons. of electrons opposite to the direction of rotation of the signal electrons, thereby separating them. Thus, the signal electron beam 6 of the secondary or reflected electrons will deflect in the first optical magnetic prism 2, the second optical magnetic prism 4 and the third optical magnetic prism 5 to the opposite side to the primary electron beam 1. Into the path of the signal electron beam 6 of secondary or reflected electrons a detector 8 can be inserted at the point of its deflection from the optical axis 3 of the system, which then strikes the signal electron beam 6 of the secondary or reflected electrons without disturbing the primary electron beam 1.

& 3202I

At the same time, in such a set of optical magnetic prisms, a complete compensation of the dispersion properties of the individual prisms in the direction of movement of the primary electron beam can be achieved.

In addition, a suitable choice of magnetic excitation of the individual prism sections can achieve zero optical power of the system so that its insertion into the primary beam path does not bring any optical power in both perpendicular directions of focusing. This is schematically illustrated in FIGS. 2 and 3. FIG. 2 is an optical diagram of an array of optical magnetic prisms 2, 4, 5 for generating a first to third homogeneous magnetic sector field in a dispersion plane. The dotted lines 9 show the direction of the primary electron beams 1 as it would have been if it had not passed through the array of optical magnetic prisms. Solid lines then show how the primary electron beam 1 is deflected by a system of optical magnetic prisms 2, 4, 5. Both primary electron beams 1, shown in dashed lines and solid lines, arrive at the same object. The amount of deflection of the primary electron beam 1 depends on the energy of the electrons. The first primary electron beam 1a contains electrons with a lower than nominal energy, while the second primary electron beam 1b contains electrons with a nominal energy.

In FIG. 3, the same is schematically shown, in dashed lines and solid lines, in a non-dispersed plane.

By further structuring the optical magnetic prisms 2, 4, 5, for example by dividing the second optical magnetic prism 4 located in the center of the system into two independent portions, the polarity of that part of the optical magnetic prisms system 2, 4, 5 can be independently changed. deflection of the signal electron beam of 6 secondary or reflected electrons. At the same time, the dispersion effect of the optical magnetic prism system 2, 4, 5 is strengthened and the spectral distribution of electrons according to their energies is obtained. Separate detection is easily realized

2C-.S.2OIV

For example, secondary and reflected electrons, respectively, the entire energy spectrum of back-emitted electrons can be detected and analyzed. This is shown in FIG. 4. The primary electron beam 1 enters the first optical magnetic prism 2, which deflects it away from the optical axis 3 of the assembly. The deflected primary electron beam 1 enters the second optical magnetic prism 4, which deflects it in the opposite direction, i.e. again deflects it to the optical axis 3 of the assembly. The primary electron beam 1 enters the third optical magnetic prism 5, which deflects it in the opposite direction, i.e. again deflects it away from the optical axis 3 of the system so as to coincide with the optical axis 3 of the system. The primary electron beam 1 excites on the observed object 7 a signal electron beam 6 of secondary or reflected electrons, which enters the optical system in the opposite direction to the primary electron beam 1. Since the direction of electron movement of the primary electron beam 1 is opposite to the direction of the signal electron beam 6 secondary or reflected electrons, the signal electron beam of 6 secondary or reflected electrons is deflected in the opposite direction and impinges on the composite electron detector 10. The greater the energy of the electrons, the less they deviate, so that their energy can be inferred from the point of impact of the electrons on the composite electron detector 10, and evaluating the signal from the composite electron detector 10 obtains the spectral distribution of electrons in the 6 electron beam or reflected electron beam. energy. Thus, the first partial signal electron beam 6a is formed by the electrons with the highest energy, the second partial signal electron beam 6b is formed by the electrons with the lower energy, the third partial signal electron beam 6c is formed by the electrons with the even lower energy, and the fourth partial signal electron beam 6d it does not hit the composite electron detector 10, it is made up of the lowest energy electrons, such as secondary electrons.

By changing the excitation of the independent part of the central prism in the opposite sense, the energy dispersion can be minimized and thus detection of all

D3202f '

-10 signal from the preparation independent of its energy distribution. This is shown schematically in FIG. 5.

To optimize the detection system in different application directions, the prism array can also be arranged in an asymmetrical configuration, both in the vertical and horizontal planes. By way of illustration, an arrangement suitable for detecting the broadest possible energy range of back-emitted signal electrons can be mentioned, see Fig. 6.

In order to detect the widest possible range of the energy spectrum of the back-emitted signal electrons, it is possible to add a prism to the prism focusing the broad-band energy spectrum to one detection plane. At this plane, spectra can be scanned either simultaneously, eg by a multi-channel detector, or by selecting individual spectral lines by moving the spectrum, eg by changing the excitation of the auxiliary prism through a fixed spectral slot followed by the detector. The spectrally integral signal can then be detected in a plane perpendicular to the spectral plane by introducing reverse magnetic polarization of the auxiliary prism, as schematically shown in FIG. 7.

The method of electron detection according to the invention can be used in the construction of scanning electron microscopes designed to examine the observed objects 7 by means of very slow electrons or electrons reflecting on the surface of the observed object 7. Reduction of the energy impact of the electrons on the observed object 7 is achieved potential up to the cathode potential, which reflects the incident electrons and creates an electrostatic immersion lens.

Fig. 8 schematically shows a first exemplary embodiment of an apparatus for carrying out the above-described method. The objective lens 11 is provided with a winding 12 disposed between the upper pole piece 13 and the lower pole piece 14. This winding 12 of the objective lens is separated from the vacuum part of the optical system by a partition 15. Inside the objective lens 11 is

2fr3r 2013 (£ £ 3202 /

In the direction of movement of the electrons in the primary electron beam 1, a first magnetic optical prism 2 is arranged, followed by a second magnetic optical prism 4 and a third magnetic optical prism 5 thereafter. The prisms 2, 4, 5 are arranged around the central axis of the objective lens 11, i.e. the optical axis 3 of the assembly, in the interior of the upper pole piece 13. A scanning system 16, which is generally octupol, is arranged below the third magnetic prism.

In the operation of the device, the primary electron beam 1 (not shown) enters the first optical magnetic prism 2, which deflects it away from the optical axis 3 (not shown). The deflected primary electron beam 1 enters the second optical magnetic prism 4, which deflects it in the opposite direction, i.e. again deflects it to the optical axis 3 of the assembly. The primary electron beam 1 enters the third optical magnetic prism 5, which deflects it in the opposite direction, i.e. again deflects it away from the optical axis 3 of the system so as to coincide with the optical axis 3 of the system. The primary electron beam 1, after passing through the scanning system 16, excites a not shown signal electron beam 6 of secondary or reflected electrons on the observed object 7, which enters the optical system in the opposite direction to the primary electron beam

1. Since the direction of movement of the electrons of the primary electron beam 1 is opposite to the direction of the signal electron beam 6 of the secondary or reflected electrons, the signal electron beam 6 deflects in the opposite direction and impinges on a detector 8 not shown. a beam of 6 secondary or reflected electrons separated from the primary electron beam 1, allowing it to be detected without disturbing the optical properties of the primary electron beam 1.

B3202f 2626-r201tf

In the case of electromagnetic objective lenses 11, the described arrangement can be supplemented by the principle of an open magnetic lens to obtain a peak resolution, thus immersing the preparation in a magnetic field, thus creating a magnetic immersion lens or a combination of an electrostatic and magnetic immersion lens.

It follows from the principles of electron optics that secondary or primary electrons reflected from the surface of the observed object 7, whose potential is close to the potential of the cathode, are again accelerated by the electrostatic field or in combination with the magnetic field by passing the electron optical system in the opposite direction they are concentrated very close to the optical axis 3 of the system and cannot be detected by the rotationally symmetrical detector because they pass through the central opening of the detector 8 necessary for the passage of the primary electrons. Their deviation from the axial trajectory is not easily possible because their energy is identical or close to that of the primary electrons. If they deviate, the trajectory of the primary electrons would be disrupted in the same way and the irradiation of the scanning beam from the optical axis of the system would be irreversible. Speculation using the Wien filter with crossed magnetic and electrostatic fields is physically justified, but practically unusable due to the enormously increasing aberrations when signal electrons are diverted to the necessary larger angles.

The above-described arrangement with a rotationally unsymmetrical electron detector 8 utilizing the electron optical properties of the magnetic optical prisms 2, 4, 5 is a system that eliminates the disadvantages of both rotationally symmetrical and other rotationally unsymmetrical detectors.

FIG. 9 schematically illustrates a second exemplary embodiment of an apparatus for carrying out the method described above. The first, second and third magnetic optical prisms 2, 4 are arranged in the shielding tube 21 of the electron microscope,

5. Instead of a magnetic lens there is an array of 17 electrostatic lenses.

’I

The apparatus is provided with an auxiliary magnetic optical prism 18 above which a light guide 19 terminated by a scintillator 20 is arranged. In the auxiliary magnetic optical prism 18 a composite electron detector 10 is provided.

In the operation of the device, the primary electron beam 1 (not shown) enters the first optical magnetic prism 2, which deflects it away from the optical axis 3 (not shown). The deflected primary electron beam 1 enters the second optical magnetic prism 4, which deflects it in the opposite direction, i.e. again deflects it to the optical axis 3 of the assembly. The primary electron beam 1 enters the third optical magnetic prism 5, which deflects it in the opposite direction, i.e. again deflects it away from the optical axis 3 of the system so as to coincide with the optical axis 3 of the system. The primary electron beam 1, after passing through the electrostatic lens assembly 17, excites an unrecognized signal electron beam 6 of secondary or reflected electrons on the observed object 7, which enters the optical system in the opposite direction to the primary electron beam 1. is opposite to the direction of the signal electron beam 6 of the secondary or reflected electrons, the signal electron beam 6 of the secondary or reflected electrons is deflected in the opposite direction and is further deflected by the auxiliary magnetic optical prism 18 and impinges on the composite electron detector 10. The magnitude of the electron deflection of the signal electron beam 6 of the secondary or reflected electrons depends on their energy, the high energy electrons, e.g., the reflected electrons, are deflected the least and thus impinge on that part of the composite electron detector 10 which is farther from the observed object 7 with low energy, eg secondary electrons, are deflected the most, thus impinging on that part of the composite electron detector 10 that is closest to the observed object

7. Thus, the reflected electron signal is easily separated from the secondary electron signal. However, a much finer division is also possible, e.g.

-14 according to energies of only secondary electrons from the signal electron beam of 6 secondary or reflected electrons.

The detector system itself is situated in the internal bore of the upper pole piece 13 as close as possible to the magnetic gap of the magnetic lens. In the space between the lens and the composite electron detector 10, in this case, an electrostatic lens array 17 is provided, representing an electrostatic multipole for scanning or correcting the electron beam astigmatism. The magnetic lens itself is closed in this case, so that the object 7 is not immersed in the magnetic field, but is only connected to the cathode potential, or the potential close to it. The actual signal electron sensors are located in the body of the composite electron detector 10. The location of the excitation coil of the lens gives space to output the image signal, either in the form of light from a scintillation type or in the form of an electrical voltage from a detector directly amplifying. The electrostatic scanning system ensures that the back-emitted electrons pass through the detector along paths close to the primary electron paths, thereby achieving large field of view on the side of low magnification and vice versa large magnification and hence resolution in the case of large magnifications.

The combination of the above composite electron detector 10 together with an electrostatic objective lens is particularly suitable for the application of mirror electron microscopy in high vacuum systems, especially surface analysis systems, etc. The detector is located under the electron gun on the optical axis 3 of the system passing through an electrostatic lens assembly 17, as close as possible to the detector. The space between the lens and the detector is suitable for placing an electrostatic scanning or correction multipole, which is also compatible with high vacuum conditions. It is suitable to locate the entire electron-optical assembly, consisting of the lens, the scanning multipole and the detector, in the magnetically shielding tube 21 so that the disturbing external magnetic fields do not modify the electron trajectories. Type of own electron sensors is »» ao2 /

26-3r20iy should be selected taking into account the possible need for heating to achieve the necessary peak vacuum.

Industrial applicability

The electron detection method according to the invention can be used in the construction of scanning electron microscopes designed to examine the observed objects 7 by means of very slow electrons or electrons reflecting on the surface of the observed object 7.

, 26ri-20y

Primary electron beam first optical magnetic prism optical axis of the system second optical magnetic prism third optical magnetic prism signal electron beam secondary or reflected electrons observed object dotted half-line detector compound electron detector objective lens objective lens winding top objective lens bottom pole lens lenses bulkhead scanning system electrostatic lens system auxiliary magnetic optical prism light guide scintillator shielding tube

Claims (6)

Patent claims Method for detecting signal electrons in an electron microscope, characterized in that the emitted primary electron beam (1) and the re-emitted signal electron beam (6) of the secondary or reflected electrons are applied above the point of incident of the primary electron beam (1) on observed object (7) first, in the direction of the path of the emitted primary electrons, by the first homogeneous magnetic sector field, whose magnetic induction vector is perpendicular to the optical axis (3) of the emitting primary electron beam (1) in one direction; a field whose magnetic induction vector is perpendicular to the optical axis (3) of the array and opposed to the magnetic induction vector of the first homogeneous magnetic sector field for attaching the emitted primary electron beam and the signal electron beam opposite the optical axis (3) of the array; then a third homogeneous magnetic sector field whose magnetic induction vector is perpendicular to the optical axis (3) of the system and parallel to the magnetic induction vector of the first homogeneous magnetic sector field to return the emitted primary electron beam (1) to the optical axis (3) of the system and electron beam (6) of secondary or reflected electrons from the optical system axis (3) after their emission from the primary electron beam (1) impact point on the observed object (7), whereupon the signal electron beam (6) of secondary or reflected electrons in the region a third or second homogeneous magnetic sector field in which the signal electron beam (6) of the secondary or reflected electrons is deviated from the path of the emitted primary electrons of the primary electron beam (1). 20 3.? .01Jy Method for detecting signal electrons in an electron microscope according to claim 1, characterized in that the signal electron beam (6) of the secondary or reflected electrons is sensed in several regions of a third or second homogeneous magnetic sector field for separately sensing different electron signaling electrons . Device for carrying out the method according to claim 1, characterized in that, in the upper pole piece (13) of the electron microscope objective lens, a set of magnetic optical prisms (2, 4, 5) arranged one below the other in the direction of electron movement in the primary electron beam (1) a first magnetic optical prism (2), a second magnetic optical prism (4) and a third magnetic optical prism (5), under which a scanning system (16) is arranged, wherein a detector is arranged outside the optical axis (3) of the system (8) for sensing signal electrons emitted from the observed object (7). Device for carrying out the method according to claim 2, characterized in that it comprises a set of magnetic optical prisms (2,4, 5) arranged in the shielding tube (21) of the electron microscope and arranged one below the other in the direction of electron movement in the primary electron beam (1). ) a first magnetic optical prism (2), a second magnetic optical prism (4) and a third magnetic optical prism (5), under which a scanning system (16) is arranged, wherein outside the optical axis (3) of the system in several regions of the third and and / or a second magnetic optical prism (5 and / or 4) is provided with a composite electron detector (10) for separately sensing signal electrons with different energies. Device according to claim 4, characterized in that (D32O2) (26,3,2013) an auxiliary magnetic optical prism (18) is provided in the region of the third and / or second magnetic optical prism (5 and / or 4). to increase the deflection of the signal electron beam (6) of secondary or reflected electrons. Device according to claim 3, characterized in that the detector (8) is formed by a scintillator (20) connected to the light of the water (19).