US3889114A - Electron microscope for dark-field illumination - Google Patents

Electron microscope for dark-field illumination Download PDF

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Publication number
US3889114A
US3889114A US449844A US44984474A US3889114A US 3889114 A US3889114 A US 3889114A US 449844 A US449844 A US 449844A US 44984474 A US44984474 A US 44984474A US 3889114 A US3889114 A US 3889114A
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United States
Prior art keywords
electron microscope
specimen
condenser
electron
condenser lens
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Expired - Lifetime
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US449844A
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English (en)
Inventor
Van Oostrum Karel Jan
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US Philips Corp
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US Philips Corp
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    • 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 or ion-optical arrangement
    • 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

Definitions

  • ABSTRACT In an electron microscope dark-field illumination is obtained by including an annular diaphragm between the electron source and the second condenser lens and by varying the energisation of the condenser lenses whilst retaining imaging of the electron source on the specimen.
  • the specimen is illuminated by a beam in the form of a hollow cone of varying apical angle.
  • those electrons are selected from the scattered beam for the purpose of image formation which leave the specimen within a narrow cone about the optical axis, irrespective of the angle of incidence.
  • the invention relates to an electron microscope hav-' ing an annular diaphragm placed about an optical axis for illuminating an object at an angle to the optical axis.
  • an electron microscope of the type described at the beginning of this specification is characterized in that it includes, viewed in the direction of propagation of the electron beam, after an electron source a first condenser lens and a second condenser lens for imaging the electron source on the specimen, in that the condenser system has a supply source which is individually adjustable for each of the condenser lenses in a comparatively large range, and in that the annular diaphragm is disposed between the electron source and the second condenser lens.
  • FIG. 2 shows in block-schematic form an apparatus for television recording of signals obtained by means of an electron microscope according to the invention.
  • an electron microscope shown schematically comprises an electron source 1, a first condensor lens 2, a second condensor lens 3, a specimen holder 4 having an object point 5, an objective lens 6, an objective diaphragm 7 and a display f screen 8 having an image point 9. So far the electron microscope does not differ in any respect from known electron microscopes and hence need not be described more fully.
  • an annular diaphragm 10 is included in the first condenser lens.
  • the annular diaphragm maybe disposed at another position, provided that this lies between the electron source 1 and the second condenser lens 3.
  • Positions comparatively near to the electron source and positions at locations .at which within a desired energisation range of the first condenser lens an image plane 11 may be situated are unpractical although not impossible. If now with a fixed position and geometry of the annular diaphragm the power of the first condenser lens is varied, the imaging plane 11 and hence an imaging point 12 is shifted along an optical axis 13 of the electron microscope.
  • the imaging point 12 acts as an object point for the second condenser lens 3.
  • the secondcondenser lens is preferably automatically energized so that the point 12 is imaged in the object point 5.
  • FIG. 1 shows in schematic section two conical illuminating beams 14 and 15 for angles of illumination 0 and 6 respectively.
  • the point 12 is a virtual point for a given energisation range of the condenser system.
  • the electrons of the illumi- I nating beam (14 or 15) are at least partly scattered in a direction within a comparatively narrow cone 16 along the optical axis 13. All the electronsscattered in this direction are transmitted by the objective diaphragm 7 and contribute to the image formation in the image plane 8. Consequently these electrons are always scattered at an angle about equal to the angle of illumination.
  • FIG. 2 shows schematically another preferred embodiment of the invention.
  • a supply source 20 for the condenser system 2, 3 includes a timer 21.
  • the timer couples a sequence of discrete illumination periods illustrated by a sequence 22 along a horizontal time axis with a sequence of discrete angles of illumination.
  • each of the two condenser lenses of the condenser system is energized according to a block sequence 23 and 24 respectively in which the horizontal time axis is given by the time sequence whilst the current strength compared at will with images obtained at another angle of illumination.
  • the period of time during which the specimen is illuminated at each angle of illumination may be programmed.
  • FIG. 1 is a schematic sectional view of the path taken by the electron beam in an electron microscope according to the invention.
  • plotted along the vertical axis determines the angle of illumination. Obviously the currents in the two sequences 23 and 24 are matched to yield optimal imaging of the electron source on the specimen. Thus a selected sequence of illumination angles can be maintained during an illumination period which can be set or programmed at will.
  • any discrete illumination angle from a selected sequence of illumination angles can be maintained during an illumination period which can be set or programmed at will.
  • This correlation between a sequence of illumination times and a sequence of illumination angles with reference to a known scattering pattern of a given structure, for example a type of atom enables the said structures to be selected from a specimen.
  • the correlation preferably consists in that the output signal is equal for all the illumination angles for the selected structure only.
  • the said condition is not satisfied; they produce a signal in the image plane which varies with the angle of illumination, and are not displayed
  • An image signal derived from a television camera tube 2 5 at each time sequence may be recorded in a store 26 of a computer.
  • such a store may comprise storage elements, permitting information from an image comprising 100 by 100 image points to be located in 100 by 100 image points.
  • Each of the said 10 locating storage elements is associated with a word store of, for example, 16 bits.v If the said time sequence for the illumination comprises four discrete time periods, which is sufficient for satisfactory discrimination, each word of 16 bits can be divided into four parts. Each part can be filled with image information from an image point for a given angle of illumination. 7
  • the complete information from an image comprising IOfimage points can be recorded for four different illumination angles.
  • the information can be suppliedfrom the camera tube to the store during a period of time to be s'elcted at will, i.e. during a number of scans to be selected at will. Both during and after recording the information stored in the store can be displayed on a monitor 27 without the information being lost. During display the contrast in the image can be set to'a desired value by additional information from the camera tube.
  • the information may also be displayed on a'colour monitor by interposition of a chromatising device 28 according to known techniques (see for exam ple German Patent Specification No. image elements having the same diffraction pattern being assigned the same colour.
  • Electron microscope having an annular diaphragm which is arranged about an optical axis and serves to illuminate a specimen at an angle to the optical axis, characterized in that the electron microscope includes, viewed in the direction of propagation of the electron beam, after an electron source a first condenser lens and a second condenser lens for imaging the electron source on the specimen, in that the condenser system is provided with a supply source which is individually adjustable for each of the condenser lenses, and in that the annular diaphragm is disposed between the electron source and the second condenser lens.
  • Electron microscope as claimed in claim 1 characterized in that the annular diaphragm is included in the construction of the first condenser lens.
  • Electron microscope as claimed in claim 4 characterized in that it includes a television camera tube coupled to the timer and an image recording device connectd to said tube.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US449844A 1973-03-28 1974-03-11 Electron microscope for dark-field illumination Expired - Lifetime US3889114A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7304298A NL7304298A (xx) 1973-03-28 1973-03-28

Publications (1)

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US3889114A true US3889114A (en) 1975-06-10

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US449844A Expired - Lifetime US3889114A (en) 1973-03-28 1974-03-11 Electron microscope for dark-field illumination

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US (1) US3889114A (xx)
JP (1) JPS49130668A (xx)
BE (1) BE812849A (xx)
CA (1) CA1002209A (xx)
DE (1) DE2412675A1 (xx)
ES (1) ES424663A1 (xx)
FR (1) FR2223831B1 (xx)
GB (1) GB1469777A (xx)
IT (1) IT1003873B (xx)
NL (1) NL7304298A (xx)
SE (1) SE392365B (xx)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099055A (en) * 1975-10-17 1978-07-04 Hitachi, Ltd. Scanning transmission electron microscope
US4214162A (en) * 1975-09-19 1980-07-22 Max-Planck-Gesellschaft Zur Forderung Der Wissenschaften E.V. Corpuscular beam microscope for ring segment focusing
US5225676A (en) * 1991-05-21 1993-07-06 Jeol Ltd. Electrooptical viewing apparatus capable of switching depth of focus
US5500527A (en) * 1993-12-28 1996-03-19 Zarubin; Alexander Electron/ion microscope with improved resolution
US20090108200A1 (en) * 2007-10-29 2009-04-30 Micron Technology, Inc. Method and System of Performing Three-Dimensional Imaging Using An Electron Microscope
US20100258719A1 (en) * 2009-04-08 2010-10-14 Carl Zeiss Nts Gmbh Particle-beam microscope
CN103388406A (zh) * 2013-07-29 2013-11-13 苏州市世好建材新技术工程有限公司 插合式铺浆器

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT353519B (de) * 1978-03-07 1979-11-26 Oesterr Studien Atomenergie Einrichtung zur buendelung des primaerionen- strahls
JPS63298949A (ja) * 1987-05-28 1988-12-06 Jeol Ltd 広狭領域が同時観察可能な分析電子顕微鏡
JPH0233843A (ja) * 1988-07-25 1990-02-05 Hitachi Ltd 走査電子顕微鏡

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2464419A (en) * 1947-12-26 1949-03-15 Rca Corp Method of and apparatus for selectively achieving electronic darkfield and bright field illumation
US3795813A (en) * 1972-03-16 1974-03-05 Max Planck Gesellschaft Changed particle optical imaging system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2464419A (en) * 1947-12-26 1949-03-15 Rca Corp Method of and apparatus for selectively achieving electronic darkfield and bright field illumation
US3795813A (en) * 1972-03-16 1974-03-05 Max Planck Gesellschaft Changed particle optical imaging system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4214162A (en) * 1975-09-19 1980-07-22 Max-Planck-Gesellschaft Zur Forderung Der Wissenschaften E.V. Corpuscular beam microscope for ring segment focusing
US4099055A (en) * 1975-10-17 1978-07-04 Hitachi, Ltd. Scanning transmission electron microscope
US5225676A (en) * 1991-05-21 1993-07-06 Jeol Ltd. Electrooptical viewing apparatus capable of switching depth of focus
US5500527A (en) * 1993-12-28 1996-03-19 Zarubin; Alexander Electron/ion microscope with improved resolution
US20090108200A1 (en) * 2007-10-29 2009-04-30 Micron Technology, Inc. Method and System of Performing Three-Dimensional Imaging Using An Electron Microscope
US8642959B2 (en) * 2007-10-29 2014-02-04 Micron Technology, Inc. Method and system of performing three-dimensional imaging using an electron microscope
US20140145089A1 (en) * 2007-10-29 2014-05-29 Micron Technology, Inc. Apparatus having a magnetic lens configured to diverge an electron beam
US9390882B2 (en) * 2007-10-29 2016-07-12 Micron Technology, Inc. Apparatus having a magnetic lens configured to diverge an electron beam
US20100258719A1 (en) * 2009-04-08 2010-10-14 Carl Zeiss Nts Gmbh Particle-beam microscope
US8471203B2 (en) * 2009-04-08 2013-06-25 Carl Zeiss Microscopy Gmbh Particle-beam microscope
CN103388406A (zh) * 2013-07-29 2013-11-13 苏州市世好建材新技术工程有限公司 插合式铺浆器

Also Published As

Publication number Publication date
NL7304298A (xx) 1974-10-01
JPS49130668A (xx) 1974-12-14
GB1469777A (en) 1977-04-06
BE812849A (fr) 1974-09-26
IT1003873B (it) 1976-06-10
ES424663A1 (es) 1976-06-01
FR2223831B1 (xx) 1977-09-30
DE2412675A1 (de) 1974-10-10
SE392365B (sv) 1977-03-21
CA1002209A (en) 1976-12-21
FR2223831A1 (xx) 1974-10-25

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