ELECTRON BEAM APPARATUS COMPRISING MONOCHROMATOR
20190154502 ยท 2019-05-23
Assignee
Inventors
Cpc classification
G01N23/2251
PHYSICS
H01J37/26
ELECTRICITY
International classification
H01J37/26
ELECTRICITY
G01N23/2251
PHYSICS
Abstract
The present invention relates to an electron beam apparatus including a monochromator in which cylindrical electrostatic lenses for deflecting a path of an electron beam in the lenses are arranged symmetrically and an aperture including a plurality of selectable slits is disposed therebetween to be able to select an electron beam having a specified energy range. The electron beam apparatus has a monochromator having high resolution and excellent stability and maintainability by disposing slits and circular openings in one aperture part in parallel arrangement, thereby improving spatial resolution and energy resolution.
Claims
1. An electron beam apparatus including a monochromator, comprising: an electron source, the monochromator limiting energy of an electron beam emitted from the electron source to a predetermined range, a lens system, and a detector, wherein the monochromator includes: an aperture part that includes a plurality of rectangular energy selection slits, a plurality of dummy slits, and a plurality of circular slits; and a position adjustment part for adjusting a position of an aperture to change the slits.
2. The electron beam apparatus including a monochromator of claim 1, wherein the monochromator includes: a first electrode part that is configured of a plurality of electrodes forming a plane xy perpendicular to an incident direction z of the electron beam, with the plurality of electrodes including a rectangular opening parallel to the incident direction z, and is configured so that electrons traveling along a central axis x.sub.0y.sub.0 of the incident direction z, are deflected by an effect of an electrostatic lens with an electric field formed by the rectangular opening when a voltage is applied to the electrodes, to different positions according to an energy distribution in a direction x of a short side of the rectangular opening of the electrodes, and are propagated in parallel to the incident direction; an aperture part that includes a plurality of rectangular energy selection slits having the short side S.sub.x in the direction x, which is consistent with a deflected direction, so as to selectively pass particles of the deflected and propagated electron beam belonging to a predetermined energy range E, E+E therethrough at a predetermined deflection position range x, x+S.sub.x, a plurality of dummy slits for selecting a position, and a plurality of circular slits; and a position adjustment part for adjusting a position of the slits according to energy of the deflected and propagated electron beam.
3. The electron beam apparatus including a monochromator of claim 2, wherein the slits of the aperture part are formed in thin film layers having a metal thin film that are formed on an upper surface and a lower surface of the central layer, a material of the central layer is silicon nitride (Si.sub.3N.sub.4), carbon (C), platinum iridium (PtIr), and molybdenum (Mo) and a thickness thereof ranges from 20 nm to 500 m, a material of the metal thin film is platinum (Pt) or gold (Au) and a thickness thereof ranges from 10 to 200 nm, a diameter of the circular slit ranges from 10 nm to 500 m, and a length of the short side S.sub.x of the rectangular energy selection slit ranges from 50 nm to 100 m and a length of the long side S.sub.y thereof ranges from 100 nm to 1000 m.
4. The electron beam apparatus including a monochromator of claim 3, wherein the aperture part includes: a holder for supporting the thin film layer; a support for connecting the holder to the position adjustment part; and a base for fixing the position adjustment part to the aperture part attaching device, and the position adjustment part moves the slit in the deflected direction x or the perpendicular direction y to the deflected direction.
5. The electron beam apparatus including a monochromator of claim 4, wherein each connection surface of the holder, the support, the position adjustment part, and the base has an angular range within 1 with respect to the long side direction of the rectangular opening of the first electrode part.
6. The electron beam apparatus including a monochromator of claim 2, wherein the plurality of rectangular energy selection slits have the same size or different sizes and are arranged to be spaced apart from each other at a predetermined interval L.sub.y in the direction y of the long side S.sub.y orthogonal to the direction x of the short side S.sub.x that is the direction in which the electron beam is deflected.
7. The electron beam apparatus including a monochromator of claim 6, wherein the predetermined interval L.sub.y at which the plurality of rectangular energy selection slits are arranged along the direction y of the long side S.sub.y orthogonal to the direction x is set to be larger than the diameter of the opening of the entrance aperture through which the electron beam is incident on a central axis x.sub.0y.sub.0 so that a current distribution of the electron beam incident on the first electrode part is limited to a predetermined size.
8. The electron beam apparatus including a monochromator of claim 6, wherein the plurality of circular slits have the same size or different sizes and the plurality of circular slits are arranged in parallel to be spaced apart from each other by a predetermined distance M.sub.x in the direction x of the short side S.sub.x, which is the deflected direction, from the plurality of rectangular energy selection slits.
9. The electron beam apparatus including a monochromator of claim 6, wherein the plurality of circular slits are arranged at a position coinciding with the central axis x.sub.0 in the incident direction.
10. The electron beam apparatus including a monochromator of claim 8, wherein when the monochromator is not limited to the energy range E, E+E, the electron beam apparatus makes the voltage applied to the first electrode part OFF to straighten the electron beam without deflecting the electron beam, and therefore the electron beam is irradiated to a sample using one of the plurality of circular slits that are placed at the position coinciding with the extending line of the central axis x.sub.0 of the incident direction.
11. The electron beam apparatus including a monochromator of claim 2, wherein the plurality of rectangular energy selection slits have the same size and are arranged at the predetermined intervals L.sub.x and L.sub.y along the direction x of the short side S.sub.x that is the direction in which the electron beam is deflected and the direction y orthogonal to the deflected direction, and the predetermined interval L.sub.y at which the plurality of rectangular energy selection slits are arranged along the orthogonal direction y is larger than the diameter of the opening of the entrance aperture through which the electron beam is incident on the central axis x.sub.0y.sub.0 so that the current distribution of the incident electron beam is limited to the predetermined size.
12. The electron beam apparatus including a monochromator of claim 2, wherein the plurality of rectangular energy selection slits include the same size and different sizes, and the plurality of slits having the same size are arranged at the predetermined interval L.sub.x along the direction x of the short side S.sub.x that is the direction in which the electron beam is deflected, the plurality of slits having different sizes are arranged at the predetermined interval L.sub.y along the direction y orthogonal to the deflected direction x, and the predetermined interval L.sub.y at which the plurality of rectangular energy selection slits are arranged along the orthogonal direction y is larger than the diameter of the opening of the entrance aperture through which the electron beam is incident on the central axis x.sub.0y.sub.0 so that the current distribution of the incident electron beam is limited to the predetermined size.
13. The electron beam apparatus including a monochromator of claim 2, wherein the number of dummy slits is two and the dummy slits are positioned, one by one, at each of both edges of the direction y orthogonal to the direction x of the short side S.sub.x that is the deflected direction from the central position of the direction x of the short side S.sub.x.
14. The electron beam apparatus including a monochromator of claim 2, wherein the plurality of circular slits are the same size or different sizes, and the circular slits are arranged along the direction y orthogonal to the direction x of the short side S.sub.x that is the deflected direction or are arranged at both edges of the orthogonal direction y.
15. The electron beam apparatus including a monochromator of claim 14, wherein when the monochromator according to the present invention is not limited to the energy range E, E+E, the electron beam apparatus makes the voltage applied to the first electrode part OFF to straighten the electron beam without deflecting the electron beam, and therefore the electron beam is irradiated to the sample using one of the plurality of circular slits that are placed at a position coinciding with the extending line of the central axis x.sub.0 of the incident direction.
16. The electron beam apparatus including a monochromator of claim 2, wherein the direction of the long side of the rectangular energy selection slit of the apparatus part is aligned so that an angle range deviating from the direction of the long side of the rectangular opening of the first electrode part is within 1.
17. The electron beam apparatus including a monochromator of claim 1, wherein the electron beam apparatus includes a second electrode part that is disposed at a rear end of the aperture part and generates an electric field to restore the electron beam passing through the energy selection slit to the central axis x.sub.0y.sub.0 of the incident direction z that is the original position at the entrance of the monochromator by deflection when a voltage is applied to the second electrode part configured of a plurality of electrodes including the opening formed in parallel to the incident direction z of the electron beam passing through the energy selection slit, and a position of the second electrode part is symmetrical to the first electrode part with respect to the aperture.
18. An electron energy loss spectroscopy (EELS) using the monochromator of claim 17.
19. A scanning electron microscope converging an electron beam on a sample, detecting a secondary signal generated from a surface of the sample and observing an image of the surface of the sample of a sample chamber by using the electron beam apparatus of claim 17.
20. A transmission electron microscope observing an magnified image of a sample by a transmission electron beam through a screen on which an electron beam transmitting through a sample of a sample chamber is enlarged and projected, by using the electron beam apparatus of claim 17.
21. A electron beam apparatus including a monochromator analyzing energy of an electron beam emitted from a sample and analyzing an element analysis chemical bonding state, a phonon state, and a plasmon state of the sample, by using the electron beam apparatus of claim 17.
22. An electron beam etching apparatus etching a surface of a sample within a sample chamber equipped with a gas introduction part by using the electron beam apparatus of claim 17.
Description
DESCRIPTION OF DRAWINGS
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EMBODIMENTS
[0044] Hereinafter, embodiments of the present invention will be described in detail as follows with reference to the accompanying drawings so that they can be easily practiced by those skilled in the art to which the present invention pertains. Before detailed description of the present invention, it is to be noted that terms or words used in the present specification and claims to be described below should not be construed as being limited to a general meaning or dictionary definition. Therefore, the configurations described in the embodiments and drawings of the present invention are merely most embodiments but do not represent all of the technical spirits of the present invention. Thus, it is to be understood that the present invention may include various equivalents thereto, and modifications thereof at the time of filing this application.
[0045]
[0046] In one embodiment of the present invention, the monochromator includes: a first electrode part 90 that is configured of a plurality of electrodes forming a plane xy perpendicular to an incident direction z of the electron beam, with the plurality of electrodes including a rectangular opening parallel to the incident direction z, and is configured so that electrons incident along a central axis x.sub.0y.sub.0 of the incident direction z, by an effect of an electrostatic lens with an electric field formed by the rectangular opening when a voltage is applied to the electrodes, are deflected to different positions 501, 502, and 503 according to an energy distribution in a direction x of a short side of the rectangular opening of the electrodes, and are propagated in parallel to the incident direction; an aperture part 60 that includes a plurality of rectangular energy selection slits 503, 120, and 121 having the short side S.sub.x in the direction x, which is consistent with a deflected direction, of so as to selectively pass particles of the deflected and propagated electron beam belonging to a predetermined energy range E, E+E therethrough at a predetermined deflection position range x, x+S.sub.x, a plurality of dummy slits 20 for selecting a position, and a plurality of circular slits 11; and a position adjustment part 861 for adjusting a position movement of the slits according to energy of the deflected and propagated electron beam.
[0047] The first electrode part is configured of a plurality of electrodes in which the rectangular openings are arranged in a row, and when a long side of the rectangular opening is set as a y axis and a short side thereof is set as an x axis, the incident electron beam moves by a predetermined micro distance x from an original point of the x axis and is incident on the original point where the y axis does not move. That is, the electron beam incident on the first electrode part is deflected and incident and is incident on a position deviating from the center of the potential formed by the opening to receive a deflection force in an x direction. At this point, since the electron beam moves in the x direction that is a direction of the short side of the rectangular opening, a trajectory of the electron beam is not changed in a y direction that is a direction of the long side thereof and changed in the x direction, such that a charged particle ray is separated by energy and propagated.
[0048] That is, the electron beam passing through the first electrode part which is configured of the plurality of electrodes in which the rectangular openings are arranged in parallel are separated into an electron beam 500 having central energy E.sub.0, an electron beam 501 having energy of a value E.sub.0E smaller than the central energy, and an electron beam 502 having energy of a value E.sub.0+E larger than the central energy and propagated. At this time, a slit 503 of the aperture part 60 is aligned (700) with the electron beam 500 having the central energy E.sub.0 to selectively pass only the electron beam having uniform energy. The alignment is made by adjusting the position adjustment part 861 for adjusting the position movement of the slit.
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[0056] In one embodiment of the present invention, the dummy slits are positioned, one by one, at each of both edges of the direction y orthogonal to the direction x of the short side S.sub.x that is the deflected direction from the central position of the direction x of the short side S.sub.x. In another embodiment of the present invention, the plurality of circular slits 11 are the same size or different sizes, and the circular slits 11 are arranged along the direction y orthogonal to the direction x of the short side S.sub.x that is the deflected direction or are arranged at both edges of the orthogonal direction y. Further, when the electron beam apparatus according to the present invention is not limited to the energy range E, E+E, it makes the voltage applied to the first electrode part OFF to straighten the electron beam without deflecting the electron beam, and therefore the electron beam is irradiated to the sample using one of the plurality of circular slits 11 that are placed at a position coinciding with the extending line of the central axis x.sub.0 of the incident direction. Further, the direction of the long side of the rectangular energy selection slit 503 is aligned so that the angle range deviating from the direction of the long side of the rectangular opening of the first electrode part is within 1.
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[0059] The electron beam apparatus including a monochromator according to the embodiment of the present invention may be used as an electron beam loss spectroscope. Further, it is possible to analyze the energy of the electron beam emitted from the sample using the electron beam apparatus including a monochromator according to an embodiment of the present invention and to analyze an element analysis chemical bonding state, phonon state, and plasmon state of the sample. The electron beam apparatus including a monochromator according to another embodiment of the present invention may function as an electron beam etching apparatus for etching a surface of a sample by introducing a gas introducing part into a sample chamber.
[0060] Hereinabove, although the embodiments of the present invention have been described in detail, the scope of the present invention is not limited thereto, but modifications and alterations made by those skilled in the art using the basic concept of the present invention defined in the following claims fall within the scope of the present invention.
[0061] All technical terms used in the present invention are used as a meaning generally understood by a person having ordinary knowledge in the art to which the present invention pertains, unless defined otherwise. Contents of all publications described in the present specification as reference documents are introduced into the present invention.
DETAILED DESCRIPTION OF MAIN ELEMENTS
[0062] 1. Slit of aperture part
[0063] 2. Cross section of coating layer of aperture part
[0064] 5. Connection structure of aperture part
[0065] 11. Circular slit
[0066] 20. Dummy slit
[0067] 21. Metal thin film on upper surface of slit
[0068] 22. Metal thin film on lower surface of slit
[0069] 23. Central layer of slit
[0070] 30. Holder
[0071] 31. Support
[0072] 32. Coupling part
[0073] 33. Base
[0074] 50. Electron beam
[0075] 52. Sample incident electron beam
[0076] 53. Sample transmitting electron beam
[0077] 54. Secondary electron
[0078] 60. Aperture part
[0079] 61. Entrance aperture
[0080] 62. Aperture part for EELS
[0081] 80. Electron energy loss spectroscopy (EELS)
[0082] 90. First electrode part
[0083] 91. Second electrode part
[0084] 120, 121. Rectangular energy selection slit
[0085] 190. First transmission lens
[0086] 290. Second transmission lens
[0087] 300. Holder coupling part
[0088] 301. Holder guide
[0089] 390. Electron source
[0090] 500. Electron beam having energy E.sub.0
[0091] 501. Electron beam having energy E.sub.0E
[0092] 502. Electron beam having energy E.sub.0+E
[0093] 503. Energy selection slit of aperture part
[0094] 700. Display equilibrium state
[0095] 810. Lens system
[0096] 811. Optical system
[0097] 830. Electron detector
[0098] 831, 832. Detector
[0099] 833. Detector for scanning transmission electron microscope
[0100] 840. Detector for TEM
[0101] 850. Sample
[0102] 860. Sample holder
[0103] 861. Position adjustment part
[0104] 900. Vacuum sample chamber
[0105] 910. Electrical control device
[0106] 920. Control computer
[0107] P1, P2. Vacuum pump