US3869611A - Particle-beam device of the raster type - Google Patents

Particle-beam device of the raster type Download PDF

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Publication number
US3869611A
US3869611A US067922A US6792270A US3869611A US 3869611 A US3869611 A US 3869611A US 067922 A US067922 A US 067922A US 6792270 A US6792270 A US 6792270A US 3869611 A US3869611 A US 3869611A
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United States
Prior art keywords
specimen
locality
axis
modifying
deflection
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Expired - Lifetime
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US067922A
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English (en)
Inventor
Friedrich Thon
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Siemens AG
Siemens Corp
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Siemens Corp
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Publication date
Priority claimed from DE19691948270 external-priority patent/DE1948270C/de
Application filed by Siemens Corp filed Critical Siemens Corp
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Publication of US3869611A publication Critical patent/US3869611A/en
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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
    • H01J37/28—Electron or ion microscopes; Electron or ion diffraction tubes with scanning beams
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/26—Electron or ion microscopes
    • H01J2237/2614—Holography or phase contrast, phase related imaging in general, e.g. phase plates

Definitions

  • ABSTRACT A raster type particle-beam device has an electrooptical axis and defines a specimen locality on the axis.
  • the device has a beam generator for issuing a particle beam along the axis toward the specimen locality, a condenser lens for focussing the beam onto the specimen locality, the lens being disposed ahead of the specimen locality and coaxial with the axis, adeflection system arranged about the axis intermediate the beam generator and the condenser lens, an imaging surface disposed beyond the specimen locality in coaxial relation to the axis for receiving the rays of the beam passing through the specimen, and a beam modifying structure for modifying the imaging properties of the beam, the beam modifying structure being disposed in the path of the beam intermediate the deflection system and the specimen locality.
  • My invention relates to a raster particle-beam devicewherein the specimen is scanned by the impinging rays in a predetermined pattern or raster.
  • these diaphragms serve to reduce or eliminate the distrubing influences of the aperture error of the objective lens and are designed as zone diaphragms with alternating ray passing and ray blocking ring-shaped zones of definite spacing.
  • the zones are dimensioned so that the zone diaphragm permits only those rays of the imaging beam to pass to the final image plane which contribute to forming images having only one character contrast, namely, either only positive phase or only negative phase.
  • This zone diaphragm takes the facts into account that various phase displacements are imparted to the rays in the objective lens as well as in the specimen which lead to an undesired influencing of the quality of the final image.
  • phase plate in the rear focal plane of the objective lens which influences or controls the phases of the rays of the beam such that they fulfill the phase conditions in the final image plane required for the desired image in spite of the phase displacements caused by passing through the specimen and the objective lens. Because a blocking of rays occur with the zone diaphragm of Hoppe which do not fulfill the requiredphase conditions, a correction of the phase errors is achieved by means of a phase plate in the beam path.
  • the invention is not concerned withthis kind of particle-beam device. Instead, the invention relates to a raster particle-beam device such as a raster particlebeam microscope wherein the specimen is scanned by the impinging rays in a raster.
  • a raster microscope of this type which is described in the form of an electron raster microscope by von Ardenne in the Zeitschrift fur Physik, Volume 109, 1938, pages 553 to 572 as well as many more recent patents as, for example, the US. Pat. No. 3,389,252 or the British Pat. No.
  • 1,128,107 contains a beam generator and sequentially, in beam direction, a deflection system for the beam, a condensor lens assembly for focussing the beam on a specimen whose image is to be formed and a registration or image plane in which the image signal of the specimen is'received.
  • a photo arrangement can be provided in this plane.
  • a detector for particles and, if required, for light quanta is used.
  • a raster particle-beam microscope constructed in this fashion and provided with a special means of this type is the subject matter of the present invention.
  • means for modifying the imaging properties of the beam are placed in the beam path intermediate the deflection system and the specimen locality.
  • the invention is based on the facts that the radiation aperture of a conventional through-radiation particlebeam microscope, that is one wherein the. specimen is not raster scanned, is generally small compared to the imaging aperture. This situation exists because the cross section of the imaging bundle of rays is determined by the objectiv aperture diaphragm and the imaging aperture is determined by the radius of this diaphragm and its spacing from the lens. In a raster particle-beam microscope just the opposite relations are presented wherein the. radiation aperture is large while the imaging aperture given by the diameter of the detector input diaphragm and the spacing of the specimen from the latter is small.
  • the modifying means such as diaphragms for modifying the image in a determined way into a raster microscope having the same operational arrangement as in the usual conventional through-beam microscopes, then the modifying means is arranged, according to the invention, between the deflection system and the specimen, that is in the irradiating portion of the microscope.
  • the diaphragm serving to block individual rays. Also.
  • an additional beam modifying means in the form of a zone diaphragm, phase plate or the likeadvantageously is installed according to the invention in beam direction ahead of the specimen.
  • the beam modifying means is arranged in the beam path between the deflection system and the condensor lens.
  • the modifying means is placed in the entrance diaphragm plane of the condensor lens. This special selection of location for the modifying means is taken because it desired to modify those rays of the beam which in the specimen plane run parallel.
  • a preferred embodiment of a microscope of the invention has two deflection systems arranged about the electro-optical axis of the microscope in beam direction and spaced axially of each other.
  • the first deflection system deflects the beam away from the electro-optical axis and the second deflection system deflects the beam toward the axis so as to intersect the latter approximately in the entrance diaphragm plane of the condensor lens.
  • the second deflection system deflects the beam toward the axis so as to intersect the latter approximately in the entrance diaphragm plane of the condensor lens.
  • the modifying means could comprise a diaphragm for blocking certain rays of the beam such as dark-field diaphragm with central receiver or a dark-field half diaphragm.
  • the radiation aperture is approximately the same as this scattering angle.
  • the advantage of the device according to theinvention of a dark-field diaphragm in the radiation portion as compared to the known use of the diaphragm in the imaging portion is manifest by the suitability of the device according to the invention for high resolution investigations.
  • the diaphragm of the l-loppe type positioned in the radiation portion of a raster microscope according to the invention can be so dimensioned that only such rays of the beam reach the specimen which are imaged on the image receiver with only'one character of contrast after passing through the condensor lens and the specimen locality, namely either only with positive contrast or only with negative contrast.
  • a raster microscope according to the invention a pre-selection of the rays before they are modified or affected by the condensor lens and the specimen.
  • phase .plate that can be located at substantially the position of the diaphragm thisembodiment of the invention configuration has the features that the modifying means includes a phase plate that pre-affects a portion of the rays of said beam so that these rays meet all the phase conditions for forming an image after passing through the condensor lens and being affected by the specimen.
  • the microscope is equipped with a beam generator of the usual construction having a point cathode 2, a
  • Wehnelt cylinder 3- and the anode 4 For example, the configuration of the beam generator'describedin German Pat. No. 1,031,447 can be applied. Also, a field emission cathode can be used.
  • deflection systems In beam direction after the beam generator there are disposed deflection systems arranged in two stages one behind the other.
  • the systems comprise two pairs of electrostatic deflection plates 5, 5' and 6, 6' which are supplied by saw tooth generators not illustrated. Additional deflection systems also not illustrated serve to defect the beam in a plane perpendicular to the plane of the drawing.
  • the application of this type of deflection system in electrostatic configuration with raster microscopes is described in British Pat. No. 1,128,107.
  • pole plates of the magnetic deflection system serve simultaneously as electrostatic deflection plates, so that the deflection in twodirections perpendicular to each other is achieved by means of a substantially unitary member.
  • a specimen 8 is situated in the back focal plane of the lens 7.
  • The'specimen is preferably arranged in an adjustable specimen stage or in a diaphragm holder as de-' scribed for example in German Pat. No. 951,882.
  • the image is registered in the final image plane 9 by means of a suitable detector. Only those rays which are let through by thedetector entrance diaphragm 10 are included to form the image.
  • the beam path delineated by the dashed line 11 results when the deflection systems 5, 5' and 6, 6 are deenergized or when the voltage applied to these systems passes through its zero value.
  • the deflection systems are so arranged and the apparatus so dimensioned that the beam is deflectedoutwardly and inwardly by the deflection system in such a way that axis 13 of the inwardly deflected beam intersects the electro-optical axis 1 at the point 14 lying in the entrance-diaphragm plane of the condensor lens 7.
  • a Hoppe type'zone diaphragm 15 is used. As indicated in the.
  • the diaphragm 17 is disposed in the imaging portion behind the specimen in contrast to the diaphragm 15 arranged according to the invention in the radiation portion of the microscope. Diaphragm 17 also serves to ensure the contrast in the registration plane 9 by blocking a portion of the rays. Basically, condensor lenses can also be used in front of the deflection systems.
  • a raster type charged particle-beam device having an electro-optical axis and defining a specimen locality on said axis, said device comprising beam generating means for issuing a beam of charged particles along said axis toward said specimen locality, a condensor lens for focussing said beam onto the specimen locality, said lens being disposed ahead of the specimen locality and coaxial with said axis, deflection means for deflecting the beam back and forth in raster fashion to raster scan a specimen placeable at the specimen locality, said deflection means arranged about said axis intermediate said beam generating means and said condensor lens, image receiving means disposed beyond the specimen locality in coaxial relation to said axis for receiving the rays of said beam passing through the specimen, and beam modifying means for modifying the imaging properties of the beam by cancelling a portion of the beam or modifying the phase of the rays thereof, said modifying means being disposed in the path of said beam in a transverse section of the beam and being
  • said modifying means being disposed in the path of said beam interme diate said deflection means and said condensor lens.
  • a raster type charged particle-beam device having an electro-optical axis and defining a specimen locality on said axis, said device comprising beam generating means for issuing a beam of charged particles along said axis toward said specimen locality, a condensor lens for focussing said beam onto the specimen locality, said lens being disposed ahead of the specimen locality and coaxial with said axis, deflection means for deflecting the beam back and forthin raster fashion to raster scan a specimen placeable at the specimen locality, said deflection means arranged about said axis intermediate said beam generating means and said condensor len's, image receiving means disposed beyond the specimen locality in coaxial relation to said axis for receiving the rays of said beam passing through the specimen, and beam modifying means for modifying the imaging properties of the beam by cancelling a portion of the beam or modifying the phase of'the rays thereof, said modifying means being disposed intermediate said deflection means and said condensor lens and
  • said modifying means being disposed in the path of said beam. in the entrance diaphragm plane of said condensor lens.
  • said modifying means comprising a diaphragm disposed in the path of said beam and arranged between said deflection system and said condensor lens for blocking selected rays of said beam.
  • said diaphragm being a dark-field diaphragm.
  • said diaphragm having mutually adjacent zones ray blocking and ray passing respectively, said zones being arranged so that only such rays reach the specimen-which are imaged on said irriage receiving means with only one character of contrast after passing through said condensor lens and the specimen locality, namely either only with positive contrast or only with negative contrast.
  • said modifying means comprising a phase plate disposed in the path of said beam for modifying the respective phases of a portion of the rays of said beam, said plate being arranged between said deflection means and said condensor lens.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Microscoopes, Condenser (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US067922A 1969-09-19 1970-08-28 Particle-beam device of the raster type Expired - Lifetime US3869611A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691948270 DE1948270C (de) 1969-09-19 Raster Korpuskularstrahlmikroskop

Publications (1)

Publication Number Publication Date
US3869611A true US3869611A (en) 1975-03-04

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ID=5746361

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US067922A Expired - Lifetime US3869611A (en) 1969-09-19 1970-08-28 Particle-beam device of the raster type

Country Status (4)

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US (1) US3869611A (enrdf_load_stackoverflow)
JP (1) JPS4830182B1 (enrdf_load_stackoverflow)
GB (1) GB1306378A (enrdf_load_stackoverflow)
NL (1) NL7013772A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020148962A1 (en) * 2001-02-09 2002-10-17 Jeol Ltd. Lens system for phase plate for transmission electron microscope and transmission electron microscope

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59758U (ja) * 1982-06-22 1984-01-06 岩崎工業株式会社 合成樹脂製密封容器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3389252A (en) * 1964-06-11 1968-06-18 Philips Corp Electron microscope having a four-pole electron-optical lens assembly and a scanning line-like electron beam
US3569698A (en) * 1968-06-28 1971-03-09 Siemens Ag Particle-beam apparatus provided with a phase-shifting foil which corrects for wave aberrations

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3389252A (en) * 1964-06-11 1968-06-18 Philips Corp Electron microscope having a four-pole electron-optical lens assembly and a scanning line-like electron beam
US3569698A (en) * 1968-06-28 1971-03-09 Siemens Ag Particle-beam apparatus provided with a phase-shifting foil which corrects for wave aberrations

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020148962A1 (en) * 2001-02-09 2002-10-17 Jeol Ltd. Lens system for phase plate for transmission electron microscope and transmission electron microscope
US6744048B2 (en) * 2001-02-09 2004-06-01 Jeol Ltd. Lens system for phase plate for transmission electron microscope and transmission electron microscope

Also Published As

Publication number Publication date
NL7013772A (enrdf_load_stackoverflow) 1971-03-23
DE1948270A1 (de) 1971-04-01
DE1948270B2 (de) 1972-07-27
GB1306378A (enrdf_load_stackoverflow) 1973-02-07
JPS4830182B1 (enrdf_load_stackoverflow) 1973-09-18

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