US3737659A - Field of view adjusting device - Google Patents

Field of view adjusting device Download PDF

Info

Publication number
US3737659A
US3737659A US00199702A US3737659DA US3737659A US 3737659 A US3737659 A US 3737659A US 00199702 A US00199702 A US 00199702A US 3737659D A US3737659D A US 3737659DA US 3737659 A US3737659 A US 3737659A
Authority
US
United States
Prior art keywords
specimen
field
electron
image
view
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 - Lifetime
Application number
US00199702A
Other languages
English (en)
Inventor
T Yanaka
K Shirota
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NIHOA DENSHI
NIHOA DENSHI JA
Original Assignee
NIHOA DENSHI
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NIHOA DENSHI filed Critical NIHOA DENSHI
Application granted granted Critical
Publication of US3737659A publication Critical patent/US3737659A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • H01J37/20—Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
    • 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
    • H01J37/147—Arrangements for directing or deflecting the discharge along a desired path

Definitions

  • ABSTRACT Field of view adjusting device for use in electron microscopes or the like having a mechanical sample adjusting means and electron deflecting means disposed in or at the rear of an objective lens, coarse adjustment being carried out by the mechanical moving means and fine adjustment by the electron deflecting means.
  • This invention relates to an electron beam apparatus, and more particularly to an improved specimen field of view adjusting device for use in electron microscopes or the like.
  • adjusting devices according to this invention it is an advantage of adjusting devices according to this invention that the field of view may be adjusted extremely, precisely, finely and smoothly at magnifications in the order of 100,000 times or more. It is a further advantage of adjusting devices according to this invention that specimen drift or shift due to thermal expansion or contraction and inertial mechanical move ment are almost entirely eliminated. The velocity of specimen drift and the magnification of the image can be measured with these adjusting devices.
  • this invention pertains to an electron microscope, comprising, for example, an electron beam source, a sample holder, a magnetic objective lens, and an image producing device, such as a fluorescent screen arranged along an optical axis.
  • an intermediate magnetic lens and a magnetic projector lens are located between the objective lens and the fluorescent screen.
  • the specimen field of view is coarsely adjusted with mechanical devices and finely adjusted by optical devices, that is, by at least one electron deflecting device positioned adjacent the image side of the objective lens. It is preferable if the deflecting means is positioned at or about the back focal plane of the objective lens. It is also preferable that the mechanical adjustment devices be disengagable from the sample holder immediately after the coarse adjustment and during the optical adjustments.
  • the power source for the deflecting means can be modulated to cause a double image on the imaging device, for example, fluorescent screen.
  • FIGS. 1 and 2 schematically illustrate the adjusting devices according to this invention
  • FIG. 3 is a graph showing variation in the isotropic astigmatism, the off-axial chromatic aberration and the image resolution as a function of the radius of movement when the specimen is adjusted by the deflecting means illustrated in FIG. 2;
  • FIG. 4 is a sectional view showing one embodiment of this invention.
  • FIG. 5 is a sectional view showing another embodiment of this invention.
  • FIG. 6 shows one observing method using this inventlon
  • FIGS. 7, 8 and 9 are schematic diagrams showing other embodiments of this invention.
  • electrons scattered by a specimen 1 pass through an objective lens 2, (shown in the drawing by an optical analog) forming an image of the specimen 1 on a plane 3.
  • the image is magnified by an intermediate lens 4 (shown as an optical analog) and a projector lens (not shown) arranged at the rear of the objective lens 2, and a final image is formed on a fluorescent screen (not shown).
  • One set of electron deflecting means 5 is arranged on the back focal plane or in the vicinity of the objective lens 2.
  • the electron deflecting means may, for example, comprise two pairs of mutually parallel charged plates, the two pairs of plates being at right angles to each other.
  • the electron deflecting means might also, for example, be two pairs of magnetic field forming coils arranged perpendicular with each other.
  • a D.C. source 6 provides the said electron deflecting means 5 with a current or voltage for deflecting the electrons from the specimen 1.
  • the deflecting means 5 is not energized, that is to say, when the control means 7 is so adjusted that no current or voltage flows from the D.C. source 6 to the deflecting means 5, only the electrons from the center portion (a) of the specimen pass through the intermediate lens 4 and the projector lens so as to be projected onto the screen.
  • the electrons emanating from the edge portion (b) form an image at point (b) as shown by the broken line.
  • the electrons are unable to pass through the intermediate lens 4 and the projector lens. Consequently, the image of the part of the specimen designated by (b) is not projected on the screen.
  • a suitable deflecting current or voltage is supplied to the deflecting means 5 by adjusting the control means 7 accordingly.
  • the control means 7 In order to project an image of portion (b), the control means 7 must be adjusted so as to produce a deflecting angle of a.
  • the electrons normally forming at (b) are directed along the electron beam axis, so as to be projected onto the fluorescent screen. In this way, the image of any part of the specimen can be optionally observed.
  • FIG. 2 shows the arrangement when the deflecting means cannot be arranged in the back focal plane of the objective lens 2. In this case, an extra set of deflecting means are required in order to obtain the same results as in FIG. 1.
  • FIG. 3 is a graph showing the effect of adjustments by deflection on certain aberrations for a particular electron microscope.
  • the accelerating voltage of the electrons was lOOKV
  • the magnetomotive force of the objective lens was 7,000 amp. turn
  • a half width of the magnetic field in the said lens was 1.5 m.m.
  • the image magnification was 250,000 times.
  • Curves A, B and C correspond to the isotropic astigmatism, the offaxial chromatic aberration and the resolving power of the final image on the photographic plate respectively.
  • the maximum moving distance of the specimen in this invention is 3 microns, a region which is 225 times that of the area of the image observed on the screen when the diameter of the screen is 120 mm. and the image magnification is 300,000 times. It has been found that regardless of magnification changes, the radius of movement is hardly affected.
  • FIG. 4 shows one embodiment of this invention.
  • An objective lens 2 consisting of a lens yoke 8, pole pieces 9 and an energizing coil 10 is mounted on an intermediate lens 4, consisting of a lens yoke 11, a nonmagnetic spacer 12 and an energizing coil 13.
  • a specimen stage 14 is arranged on the objective lens 2 via balls 15, the said stage supporting a holder 16 for holding the specimen.
  • Two moving rods 17 are mounted at suitable positions in the specimen chamber wall 18, one end of each of which are in contact with the stage 14.
  • a spring 19 is suitably arranged between the said wall 18 and the stage 14.
  • a non-magnetic cylinder 20 is arranged in the objective lens yoke 8 coaxially with the beam axis.
  • a first deflecting means 5a and a second deflecting means 5b are attached to the upper portion and the lower portion of the cylinder 20 respectively.
  • the mechanical specimen moving device consisting of the moving rods 17 and the spring 19 is used for coarse adjustment of the specimen and the deflecting means 5a and 5b is used for fine adjustment.
  • FIG. 5 is a variation of the arrangement described in FIG. 4.
  • the stage 14 includes two members 21 and 22, member 22 acting as a support for the specimen holder 16.
  • Members 21 and 22 are held firmly in contact by springs 23 which are suspended between the specimen chamber wall 18 and the member 21.
  • the member 22 is slidably disposed on supporting legs 24 mounted on the upper surface of the objective lens 2.
  • Springs 25, suspended between the objective lens 2 and the member 22, serve to hold the member 22 in slidable contact with the supporting legs 24.
  • the moving rods 17 are mounted so that one end of each rod is in contact with the member 21.
  • member 21 is moved which in turn causes member 22 to move, thereby changing the specimen field of view.
  • a plurality of levers 26 are pivotally mounted in the specimen chamber 18 above which rods 27 are arranged in contact.
  • the member 21 is made to separate from the member 22 by the depressing action of the levers 26.
  • a deflecting current or voltage is applied to the deflecting means 50 and 5b, and the specimen is finely adjusted within a radius of 3 microns.
  • FIG. 6 illustrates a method in accordance with this invention by which high resolution and broad field image photographs can be obtained.
  • the deflecting means operates so that the specimen image is formed on the screen in the order A B C D E F G II I.
  • Each of the said image portions is photographed and after being developed, each film is pieced together in accordance with the above order.
  • FIGS. 7, 8 and 9 show other embodiments of this invention.
  • the external end of the moving rod 17 contacts a lever 30 which is activated by a screw bar 31.
  • the other end of the said screw bar is fitted with a bevel gear 32 which is in turn meshed with a second bevel gear 33 attached to a shaft 34 which passes through a gear box 35.
  • the shaft 34 also carries a spur gear 36 which is shown meshed with a second spur gear 39 carried by a slidable shaft 37 to the external end of which knob 38 is fitted.
  • a further shaft 40 likewise carrying a spur gear 41 runs from the gear box 35 through to the control means 7.
  • a potentiometer forming part of the said control means is adjusted by rotating the said shaft 40, thereby varying the deflecting current or voltage.
  • stage 14 is moved by rotating knob 38 via the train of linkages and gears, etc.
  • lever 30 pushes rod 17 according to the degree in which knob 38 is rotated, thereby controllably moving the specimen stage 14.
  • potentiometer forming part of the control means 7 is controllably adjusted by knob 38 with the result that the deflecting current or voltage supplied to the deflecting means 5 is similarly adjusted, and the specimen field of view is varied by electron deflection.
  • One application of this invention is to measure the magnification of the image. This is explained by referring to FIG. 8.
  • an A.C. source 42 and a switching means 43 are provided in addition to the DC. source 6 and the control means 7.
  • the switching means 43 is connected to the A.C. source 42 whereby the AC. current or voltage is supplied to the deflecting means 5a and 5b.
  • the electrons from the specimen are then periodically directed along the lines a and a".
  • a double image of the specimen is formed on the screen, and the magnification is determined by measuring the distance between the two images.
  • the field of view is coarsely adjusted mechanically, and finely adjusted optically, that is, by electron deflection.
  • mechanical and optical adjustments By combining mechanical and optical adjustments, the inherent drawbacks of each are almost entirely eliminated.
  • An accurate, fine and smooth adjustment is provided without causing aberrations or affecting image resolution.
  • the devices according to this invention have added capabilities, that is, they can be adapted to measure specimen drift and magnification.
  • an electron optical system having an optical axis, for focusing and projecting said beam comprising at least an objective lens
  • a field of view adjusting 6 device comprising:
  • At least one electron deflection means disposed adjacent the image side of the objective lens for deflecting the image beam for fine adjustment of the field of view projected centrally on the imaging device within limits representative of a three micron radius of the specimen traversely of the optical axis and thereby maintaining an image of the desired portion of the specimen within the three micron radius projected centrally on the imaging device.
  • the improvement in specimen field of view adjusting device set forth in claim 1 comprising a DC. voltage source for actuating the deflecting means, means for controlling the said deflecting means by adjusting the DC. voltage source, an AC. voltage source, and a switching means for engaging or disengaging the DC. and AC. voltage sources such that when the A.C. source is applied to the deflecting means a double image suitable for determination of magnification is produced on the imaging device.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Electron Sources, Ion Sources (AREA)
US00199702A 1969-04-08 1971-11-17 Field of view adjusting device Expired - Lifetime US3737659A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP44027401A JPS4833903B1 (enrdf_load_stackoverflow) 1969-04-08 1969-04-08

Publications (1)

Publication Number Publication Date
US3737659A true US3737659A (en) 1973-06-05

Family

ID=12220028

Family Applications (1)

Application Number Title Priority Date Filing Date
US00199702A Expired - Lifetime US3737659A (en) 1969-04-08 1971-11-17 Field of view adjusting device

Country Status (3)

Country Link
US (1) US3737659A (enrdf_load_stackoverflow)
JP (1) JPS4833903B1 (enrdf_load_stackoverflow)
DE (1) DE2016753C3 (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3917946A (en) * 1972-04-12 1975-11-04 Philips Corp Electron-optical device for the recording of selected diffraction patterns
US4283627A (en) * 1978-12-01 1981-08-11 Hitachi, Ltd. Electron microscope
US4376891A (en) * 1980-03-05 1983-03-15 Rauscher Guenter Method and apparatus for producing electron beam diffraction patterns
US4379231A (en) * 1979-03-14 1983-04-05 Hitachi, Ltd. Electron microscope
US4623783A (en) 1984-06-15 1986-11-18 Jeol Ltd. Method of displaying diffraction pattern by electron microscope
US5008536A (en) * 1988-12-05 1991-04-16 Hitachi, Ltd. Electron microscope having electrical and mechanical position controls for specimen and positioning method
US6444991B1 (en) * 1999-07-19 2002-09-03 Jeol Ltd. Scanning charged-particle beam instrument

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2257774A (en) * 1937-02-18 1941-10-07 Ardenne Manfred Von Electronic-optical device
US2515926A (en) * 1946-01-12 1950-07-18 Hartford Nat Bank & Trust Co Device for examining crystalline structure by means of cathode rays
US2617041A (en) * 1949-11-15 1952-11-04 Farrand Optical Co Inc Stereoscopic electron microscope
US3171955A (en) * 1962-03-30 1965-03-02 Rca Corp Temperature controlled and adjustable specimen stage for scientific instruments
US3517191A (en) * 1965-10-11 1970-06-23 Helmut J Liebl Scanning ion microscope with magnetic sector lens to purify the primary ion beam

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1019393B (de) * 1941-09-13 1957-11-14 Dr Heinrich Herbst Elektronenmikroskop
DE1019397B (de) * 1943-12-04 1957-11-14 Dr Heinrich Herbst Elektronen- oder Ionenmikroskop
GB832500A (en) * 1955-12-12 1960-04-13 Ass Elect Ind Improvements relating to electron optical apparatus
DE1203401B (de) * 1962-02-17 1965-10-21 United Aircraft Corp Einrichtung zur Justierung eines Ladungstraegerstrahles und Verfahren zur Justierung eines Ladungstraegerstrahles

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2257774A (en) * 1937-02-18 1941-10-07 Ardenne Manfred Von Electronic-optical device
US2515926A (en) * 1946-01-12 1950-07-18 Hartford Nat Bank & Trust Co Device for examining crystalline structure by means of cathode rays
US2617041A (en) * 1949-11-15 1952-11-04 Farrand Optical Co Inc Stereoscopic electron microscope
US3171955A (en) * 1962-03-30 1965-03-02 Rca Corp Temperature controlled and adjustable specimen stage for scientific instruments
US3517191A (en) * 1965-10-11 1970-06-23 Helmut J Liebl Scanning ion microscope with magnetic sector lens to purify the primary ion beam

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3917946A (en) * 1972-04-12 1975-11-04 Philips Corp Electron-optical device for the recording of selected diffraction patterns
US4283627A (en) * 1978-12-01 1981-08-11 Hitachi, Ltd. Electron microscope
US4379231A (en) * 1979-03-14 1983-04-05 Hitachi, Ltd. Electron microscope
US4376891A (en) * 1980-03-05 1983-03-15 Rauscher Guenter Method and apparatus for producing electron beam diffraction patterns
US4623783A (en) 1984-06-15 1986-11-18 Jeol Ltd. Method of displaying diffraction pattern by electron microscope
US5008536A (en) * 1988-12-05 1991-04-16 Hitachi, Ltd. Electron microscope having electrical and mechanical position controls for specimen and positioning method
US6444991B1 (en) * 1999-07-19 2002-09-03 Jeol Ltd. Scanning charged-particle beam instrument

Also Published As

Publication number Publication date
JPS4833903B1 (enrdf_load_stackoverflow) 1973-10-17
DE2016753A1 (de) 1970-10-15
DE2016753C3 (de) 1981-05-07
DE2016753B2 (de) 1973-08-02

Similar Documents

Publication Publication Date Title
Champness Electron diffraction in the transmission electron microscope
Telieps et al. An analytical reflection and emission UHV surface electron microscope
US7777185B2 (en) Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope
US4044255A (en) Corpuscular-beam transmission-type microscope including an improved beam deflection system
JP6173862B2 (ja) 電子顕微鏡
US7939801B2 (en) Electron beam observation device using pre-specimen magnetic field as image-forming lens and specimen observation method
JP2001511303A (ja) 粒子−光学装置における球面収差補正用の補正デバイス
JP2004214065A (ja) 電子線装置
JP2810797B2 (ja) 反射電子顕微鏡
US2802110A (en) Electron microscope
JP7064271B2 (ja) 電子顕微鏡における収差の測定および制御
US3737659A (en) Field of view adjusting device
GB2161018A (en) Electron microscope lenses
Martin et al. A new electron microscope
JP2003504803A5 (enrdf_load_stackoverflow)
GB2162682A (en) Method of displaying electron diffraction patterns
US3660657A (en) Electron microscope with multi-focusing electron lens
US3256433A (en) Energy-selecting electron microscope using electron optics
Haine The design and construction of a new electron microscope
US3588586A (en) Apparatus for correcting electron beam deflection
Williams et al. The instrument
JPS5944743B2 (ja) 走査電子顕微鏡等用照射電子レンズ系
US2253542A (en) Electron scanning microscope
US4492870A (en) Angular limitation device in a charged particle beam system
US3401261A (en) Apparatus for investigating magnetic regions in thin material layers