CA1061477A - Electron microscope - Google Patents
Electron microscopeInfo
- Publication number
- CA1061477A CA1061477A CA259,926A CA259926A CA1061477A CA 1061477 A CA1061477 A CA 1061477A CA 259926 A CA259926 A CA 259926A CA 1061477 A CA1061477 A CA 1061477A
- Authority
- CA
- Canada
- Prior art keywords
- electron
- electron microscope
- electron beam
- power supply
- illuminating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
- H01J37/153—Electron-optical or ion-optical arrangements for the correction of image defects, e.g. stigmators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
- H01J37/147—Arrangements for directing or deflecting the discharge along a desired path
- H01J37/1478—Beam tilting means, i.e. for stereoscopy or for beam channelling
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/21—Means for adjusting the focus
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
- H01J37/261—Details
- H01J37/265—Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Electron Sources, Ion Sources (AREA)
Abstract
ABSTRACT:
In an electron microscope having a compara-tively high resolution, a tilting motion about a point in an object to be imaged is imparted to the illuminat-ing electron beam in order to adjust the coherence of the exposure of an object. For the exposure aperture, the aperture given by the degree of deflection then takes the place of the very small aperture of the illu-minating electron beam. A preferred embodiment includes a correction device for the non-axial passage of the electron beam through a subsequent lens in the electron microscope. Operation with a conical exposure involving a present apex is also feasible.
In an electron microscope having a compara-tively high resolution, a tilting motion about a point in an object to be imaged is imparted to the illuminat-ing electron beam in order to adjust the coherence of the exposure of an object. For the exposure aperture, the aperture given by the degree of deflection then takes the place of the very small aperture of the illu-minating electron beam. A preferred embodiment includes a correction device for the non-axial passage of the electron beam through a subsequent lens in the electron microscope. Operation with a conical exposure involving a present apex is also feasible.
Description
PHN. 8128.
The invention relates to an electron micros-cope, comprising an electron gun for generating an illu-minating electr~n beam and a devioe for the apparent enlargement of the aperture of the illuminating electron beam.
Electron microscope, notably high-resolution types, have a drawback in that, due to the c~mparatively small aperture of the illuminating electron beam, the depth of focus of the image is so large that exact adjustment of an image plane is impeded thereby.
British Patent Specification 687,207 which issued to MetrDpolitan-Vickers Electrical Cbmpany Limited and published on February 11, 1953 describes an electron microscope in which it is attempted to eli-minate this drawback by superposing an alternating image having a comparatively high frequency on the focussing field of the condenser lens. The focal point of the condenser lens is then displaced over a given traject along the opkical axis of the electron microscope. This re~llts in a variable object distan oe for the objective lens, a varying aperture for the illuminating electron beam thus being r~l;zed, so that optimum focus can be more readily adjusted. However, this is acco~panied by an additional contribution to spherical aberation, a restriction in the freedom of choice of the exposure intensity in the object, and a variation of the real beam aperture across the object. ~ue to the varying , ~ ~,,, ` 10~1477 P~N. 8128.
. 1-8-1976.
brightness in the image, this method cannot be used for making recordings.
The invention has for i-ts object to provide an electron microscope in which a comparatively large apparent aperture can be realized without giving rise to the said drawbacks, To this end, an electron micros-cope of the kind set forth according to the invention is characterized in that the device ~or the apparent enlargement o~ the aperture comprises a beam deflection device which includes a power supply source ~or tilting the illuminating electron beam about a point situated in an object plane.
In an electron microscope in accordance with the invention, the beam current is not at all influenced for introducing a quasi large aperture, because the transverse dimen~ion of the electron beam remains constant in the object plane, and no axial shift of the object point in the illuminating beam occurs either. ~riewed in the transverse direction, an object of the illuminat-ing beam describes a rather arbitrary figure about the optical axis. The transverse dimensions of this figur~
as well as the registration in the figure can be chosen substantially at random, provided that the tilting point is always situated in the object plane. Because no de-focussing of the beam occurs, the illumination intensity in the image plane is constant, and the pursued apparent coherence increase of the illuminating beam can also be used during the making or studying of recordings. In a 10~477 PHN. 8128.
1-8-1976.
preferred embodiment it is possible, for the non-axi~l passing of the e]ectron beam through the objective lens, to apply a given correction, coupled to the degree of transverse displacement of the beam, to the excitation of the relevant lens.
Some preferred embodiments of an electron microscope in accordance with the invention will be described in detail hereinafter with reference to the drawing. The drawing diagrammatically shows an electron microscope comprising an electron gun 1 which preferably comprises a field emission source 2 for generating an electron beam having a comparativcly high density or a comparatively small cross-section. Opposite the emis-sion source 2 there is arranged~an anode 3 and, proceed-ing in the direction of the electron beam, a succession of a beam alignment device 4~ a condens~r lens 5, a beam wobbler 6, an objective lens 7 comprising pole shoes 8 an object 9 comprising an object adjustment device 10, an intermediate lens 11, and a projection lens 12. An image space 13 of the electron microscope accommodates a camera 14 and a phosphor screen 15 which can be ob-served through a window 16. All electron-optical ele-ments are accommodated in a housing 17 which comprises, besides the window 16, a passage 18 for applying the necessary potentials and vacuum duct 19, comprising a connection 20 for a pumping device 20.
A power supply source 21 for the wobbler is . :' 1061477 PHN. 81Z8.
1-8-1976.
constructed in accordance with the invention so that a tilting movement about a point 22 in the object can be imparted to an electron beam. The power supply source is preferably also controlled by the high voltage to be applied; this is diagrammatically shown by way of the connection line 23.
A beam wobbler usually comprises two sets of electromagnetic coils whereby an electron beam is first deflected in known manner from the optical axis 24 and subsequently deflected again to a given point on the optical axis, The latter point on the optical axis is referred to as tho -tilting point in which the bea~ is incident from all directions within a conical circum-ference. ~ base plane of this co~ne is Ol is not scanned by the beam; consequently, viewed in the time, the beam can describe only the conical surface of fill the entire cone. The base surface of the cone may have any shape, For reasons of s~nmetry, a circle or a rec-tangle is preferably used as the base. Notably in the case of a circle, the beam can then describe a helix, for example, by utilizing power supply by means of two sine wave generators, powered slightly out of phase, whilst in the case of a rectangle, the movement of the beam is that of a scanning bcam, as in a television system, by way of a corresponding power supply.
If the wobbler is actuated in this manner, the object is exposed, measured in the time, with an.
, ... .. , , -- . . -- , . , , , . . . . , , .. . , . . . , ... . , . , = .
1061477 PHN. 8128.
1-8-1976.
.
aperturc which is given by the apex of the cone and which, obviously, may amount to as much as, for example, 1000 times the aperture of the electron beam itself.
During this beam deflection, the beam current is not influenced and the object point is not shifted in the axial direction for the exposure. Like in the said British Patent Specification 687,207, correction for spherical aberration is also possible. To this end, it is merely necessary in an electron microscope in accordance with the invention to control the appropri-ate lens, in this case, for example, the objective lens, in dependence of the radial position of the electron beam. Contrax~y to the correction in the known electron microscope, the beam in the electron microscope in ac-cordance with the invention is n~t wider, but only does not pass paraxially through the lens. On the basis of a paraxial beam path of the non-deflected electron beam~
the spherical aberration which would occur due to the deflection can thus be fully compensated for. As a result of the addition of an adjustable control member for the power supply of the deflection device, a pre-ferred embodiment of an electron microscope in accord-ance with the invention enables operation with a conical exposure with a presettable apex or series of apexes.
Exposure is also possible from a fixed point or a series of fixed points outside the optical axis. As resultS the nature of the exposure can be adapted, for example, to special properties of the object to be examined.
. .
.. . . . . . . . . . . .. . . ... .. .. . . .
The invention relates to an electron micros-cope, comprising an electron gun for generating an illu-minating electr~n beam and a devioe for the apparent enlargement of the aperture of the illuminating electron beam.
Electron microscope, notably high-resolution types, have a drawback in that, due to the c~mparatively small aperture of the illuminating electron beam, the depth of focus of the image is so large that exact adjustment of an image plane is impeded thereby.
British Patent Specification 687,207 which issued to MetrDpolitan-Vickers Electrical Cbmpany Limited and published on February 11, 1953 describes an electron microscope in which it is attempted to eli-minate this drawback by superposing an alternating image having a comparatively high frequency on the focussing field of the condenser lens. The focal point of the condenser lens is then displaced over a given traject along the opkical axis of the electron microscope. This re~llts in a variable object distan oe for the objective lens, a varying aperture for the illuminating electron beam thus being r~l;zed, so that optimum focus can be more readily adjusted. However, this is acco~panied by an additional contribution to spherical aberation, a restriction in the freedom of choice of the exposure intensity in the object, and a variation of the real beam aperture across the object. ~ue to the varying , ~ ~,,, ` 10~1477 P~N. 8128.
. 1-8-1976.
brightness in the image, this method cannot be used for making recordings.
The invention has for i-ts object to provide an electron microscope in which a comparatively large apparent aperture can be realized without giving rise to the said drawbacks, To this end, an electron micros-cope of the kind set forth according to the invention is characterized in that the device ~or the apparent enlargement o~ the aperture comprises a beam deflection device which includes a power supply source ~or tilting the illuminating electron beam about a point situated in an object plane.
In an electron microscope in accordance with the invention, the beam current is not at all influenced for introducing a quasi large aperture, because the transverse dimen~ion of the electron beam remains constant in the object plane, and no axial shift of the object point in the illuminating beam occurs either. ~riewed in the transverse direction, an object of the illuminat-ing beam describes a rather arbitrary figure about the optical axis. The transverse dimensions of this figur~
as well as the registration in the figure can be chosen substantially at random, provided that the tilting point is always situated in the object plane. Because no de-focussing of the beam occurs, the illumination intensity in the image plane is constant, and the pursued apparent coherence increase of the illuminating beam can also be used during the making or studying of recordings. In a 10~477 PHN. 8128.
1-8-1976.
preferred embodiment it is possible, for the non-axi~l passing of the e]ectron beam through the objective lens, to apply a given correction, coupled to the degree of transverse displacement of the beam, to the excitation of the relevant lens.
Some preferred embodiments of an electron microscope in accordance with the invention will be described in detail hereinafter with reference to the drawing. The drawing diagrammatically shows an electron microscope comprising an electron gun 1 which preferably comprises a field emission source 2 for generating an electron beam having a comparativcly high density or a comparatively small cross-section. Opposite the emis-sion source 2 there is arranged~an anode 3 and, proceed-ing in the direction of the electron beam, a succession of a beam alignment device 4~ a condens~r lens 5, a beam wobbler 6, an objective lens 7 comprising pole shoes 8 an object 9 comprising an object adjustment device 10, an intermediate lens 11, and a projection lens 12. An image space 13 of the electron microscope accommodates a camera 14 and a phosphor screen 15 which can be ob-served through a window 16. All electron-optical ele-ments are accommodated in a housing 17 which comprises, besides the window 16, a passage 18 for applying the necessary potentials and vacuum duct 19, comprising a connection 20 for a pumping device 20.
A power supply source 21 for the wobbler is . :' 1061477 PHN. 81Z8.
1-8-1976.
constructed in accordance with the invention so that a tilting movement about a point 22 in the object can be imparted to an electron beam. The power supply source is preferably also controlled by the high voltage to be applied; this is diagrammatically shown by way of the connection line 23.
A beam wobbler usually comprises two sets of electromagnetic coils whereby an electron beam is first deflected in known manner from the optical axis 24 and subsequently deflected again to a given point on the optical axis, The latter point on the optical axis is referred to as tho -tilting point in which the bea~ is incident from all directions within a conical circum-ference. ~ base plane of this co~ne is Ol is not scanned by the beam; consequently, viewed in the time, the beam can describe only the conical surface of fill the entire cone. The base surface of the cone may have any shape, For reasons of s~nmetry, a circle or a rec-tangle is preferably used as the base. Notably in the case of a circle, the beam can then describe a helix, for example, by utilizing power supply by means of two sine wave generators, powered slightly out of phase, whilst in the case of a rectangle, the movement of the beam is that of a scanning bcam, as in a television system, by way of a corresponding power supply.
If the wobbler is actuated in this manner, the object is exposed, measured in the time, with an.
, ... .. , , -- . . -- , . , , , . . . . , , .. . , . . . , ... . , . , = .
1061477 PHN. 8128.
1-8-1976.
.
aperturc which is given by the apex of the cone and which, obviously, may amount to as much as, for example, 1000 times the aperture of the electron beam itself.
During this beam deflection, the beam current is not influenced and the object point is not shifted in the axial direction for the exposure. Like in the said British Patent Specification 687,207, correction for spherical aberration is also possible. To this end, it is merely necessary in an electron microscope in accordance with the invention to control the appropri-ate lens, in this case, for example, the objective lens, in dependence of the radial position of the electron beam. Contrax~y to the correction in the known electron microscope, the beam in the electron microscope in ac-cordance with the invention is n~t wider, but only does not pass paraxially through the lens. On the basis of a paraxial beam path of the non-deflected electron beam~
the spherical aberration which would occur due to the deflection can thus be fully compensated for. As a result of the addition of an adjustable control member for the power supply of the deflection device, a pre-ferred embodiment of an electron microscope in accord-ance with the invention enables operation with a conical exposure with a presettable apex or series of apexes.
Exposure is also possible from a fixed point or a series of fixed points outside the optical axis. As resultS the nature of the exposure can be adapted, for example, to special properties of the object to be examined.
. .
.. . . . . . . . . . . .. . . ... .. .. . . .
Claims (7)
1. An electron microscope, comprising an electron gun for generating an illuminating electron beam objective lens means directing said beam to an object plane, projection lens means directing said beam from said object plane to an image plane, and a device for the apparent enlargement of the aperture of the illuminating electron beam, character-ized in that the device for the apparent enlargement of the aperture comprises a beam deflection device which includes a power supply source for tilting the illumination electron beam about a point situated in said object plane.
2. An electron beam apparatus as claimed in claim 1, characterized in that the electron gun comprises a field-emission source.
3. An electron microscope as claimed in claim 1, characterized in that the power supply source for the deflection device comprises means for helically deflect-ing the illuminating electron beam.
4. An electron microscope as claimed in claim 1, characterized in that the power supply source for the deflection device comprises means for grid-like deflec-tion of the illuminating electron beam.
5. An electron microscope as claimed in claim 1, characterized in that the power supply source for the beam deflection device comprises a control member for exposing the object from fixed, presettable directions.
6. An electron microscope as claimed in claim 5, characterized in that the control member is adapted to realize a conical exposure with a presettable apex or series of successive apexes.
7. An electron microscope as claimed in claim 1 com-prising a correction device controlled by the radial deflection of the electron beam and which serves for a subsequent electron-optical lens.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7510276A NL7510276A (en) | 1975-09-01 | 1975-09-01 | ELECTRONIC MICROSKOP. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1061477A true CA1061477A (en) | 1979-08-28 |
Family
ID=19824390
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA259,926A Expired CA1061477A (en) | 1975-09-01 | 1976-08-26 | Electron microscope |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5847825B2 (en) |
| CA (1) | CA1061477A (en) |
| DE (1) | DE2637753A1 (en) |
| FR (1) | FR2322452A1 (en) |
| GB (1) | GB1563014A (en) |
| NL (1) | NL7510276A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL7804038A (en) * | 1978-04-17 | 1979-10-19 | Philips Nv | ELECTRONIC MICROSKOP. |
| JPS55121259A (en) * | 1979-03-14 | 1980-09-18 | Hitachi Ltd | Elelctron microscope |
| EP1049131B1 (en) | 1999-03-31 | 2008-08-13 | Advantest Corporation | Particle beam apparatus for tilted observation of a specimen |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL245866A (en) * | 1958-11-29 | |||
| JPS5623272B2 (en) * | 1973-11-19 | 1981-05-29 |
-
1975
- 1975-09-01 NL NL7510276A patent/NL7510276A/en not_active Application Discontinuation
-
1976
- 1976-08-21 DE DE19762637753 patent/DE2637753A1/en not_active Ceased
- 1976-08-26 CA CA259,926A patent/CA1061477A/en not_active Expired
- 1976-08-27 GB GB3573076A patent/GB1563014A/en not_active Expired
- 1976-08-28 JP JP51102218A patent/JPS5847825B2/en not_active Expired
- 1976-09-01 FR FR7626413A patent/FR2322452A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1563014A (en) | 1980-03-19 |
| JPS5847825B2 (en) | 1983-10-25 |
| NL7510276A (en) | 1977-03-03 |
| FR2322452B1 (en) | 1980-12-12 |
| JPS5230154A (en) | 1977-03-07 |
| DE2637753A1 (en) | 1977-03-03 |
| FR2322452A1 (en) | 1977-03-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6329659B1 (en) | Correction device for correcting the lens defects in particle-optical apparatus | |
| CN104488064B (en) | For the device and method on the surface for checking sample | |
| US4983832A (en) | Scanning electron microscope | |
| JPH11148905A (en) | Electron beam inspection method and apparatus therefor | |
| JP4527289B2 (en) | Particle optics including detection of Auger electrons | |
| US4199681A (en) | Method and apparatus for automatically focusing an electron beam in a scanning beam device | |
| US3702398A (en) | Electron beam apparatus | |
| US3795809A (en) | Scanning electron microscope with conversion means to produce a diffraction pattern | |
| US4095104A (en) | Electron microscope | |
| US5300775A (en) | Method of selecting a spatial energy spread within an electron beam, and an electron beam apparatus suitable for carrying out such a method | |
| JP3101114B2 (en) | Scanning electron microscope | |
| CA1061477A (en) | Electron microscope | |
| US6653632B2 (en) | Scanning-type instrument utilizing charged-particle beam and method of controlling same | |
| US5081354A (en) | Method of determining the position of electron beam irradiation and device used in such method | |
| US3917946A (en) | Electron-optical device for the recording of selected diffraction patterns | |
| JPS5854784Y2 (en) | Stereo scanning electron microscope | |
| JP2726538B2 (en) | electronic microscope | |
| JP4283839B2 (en) | Astigmatism adjustment method using electron beam apparatus | |
| JP7361213B2 (en) | Charged particle beam device, control method for charged particle beam device | |
| JPS63216256A (en) | Charged particle beam device | |
| US2661427A (en) | Focusing aid for electron microscopes | |
| JP7453273B2 (en) | Charged particle beam device and method for controlling charged particle beam device | |
| US3483427A (en) | Lens for electron beam recorder | |
| JP2008097902A5 (en) | ||
| JP2001243904A (en) | Scanning electron microscope |