US3717761A - Scanning electron microscope - Google Patents

Scanning electron microscope Download PDF

Info

Publication number
US3717761A
US3717761A US00133894A US3717761DA US3717761A US 3717761 A US3717761 A US 3717761A US 00133894 A US00133894 A US 00133894A US 3717761D A US3717761D A US 3717761DA US 3717761 A US3717761 A US 3717761A
Authority
US
United States
Prior art keywords
specimen
electron
lens
magnetic field
electron microscope
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
US00133894A
Other languages
English (en)
Inventor
H Koike
K Ueno
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.)
Jeol Ltd
Original Assignee
Jeol Ltd
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 Jeol Ltd filed Critical Jeol Ltd
Application granted granted Critical
Publication of US3717761A publication Critical patent/US3717761A/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
    • H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
    • H01J37/28—Electron or ion microscopes; Electron or ion diffraction tubes with scanning beams

Definitions

  • the specimen is situated within a high excitation objective lens.
  • the prefield that part of the magnetic lens field before the specimen
  • the post-field that part of the magnetic lens after the specimen and usually below the specimen
  • FIG. 1 shows a scanning electron microscope in which a specimen is positioned in a magnetic field produced by an electron lens
  • FIG. 2 is an analogous optical view of a modified embodiment of the microscope shown in FIG. 1;
  • FIG. 3 shows an electron microscope in which a specimen is positioned in an objective lens
  • FIG. 4 is an analogous optical view of the electron microscope shown in FIG. 3;
  • FIGS. 5, 6 and 7 show modified embodiments of the electron microscope shown in FIG. 3;
  • FIG. 8 shows the magnetic distribution of the objective lens used in FIG. 7;
  • FIGS. 9 and 10 show other modified embodiments according to this invention.
  • an electron beam produced by an electron gun 1 passes through a condenser lens 2.
  • a coil 3, in the condenser lens 2 is supplied with excitation current by a power source 4, thereby enabling the electron beam to be focused by the magnetic field produced by the lens 2.
  • the focused electron beam is then deflected by, for example, a magnetic field produced by a deflecting means 5 and irradiated on a specimen 6 which is placed within the magnetic field produced by a high excitation electron lens 7.
  • a scanning signal is supplied to the deflecting coils 5 by a scanning signal generating circuit 13 causing the incident electron beam to scan the surface of the specimen 6.
  • Secondary electrons are emitted from the specimen by the irradiation of the incident electron beam. Furthermore, since the pre-field of the electron lens 7 extends to the upper part of the deflection means 5, the secondary electrons are spirally focused along the electron optical axis in the upper direction. Finally, the said electrons are detected by a detector 8 and a signal is supplied to a display means 12. To ensure that the secondary electrons are effectually detected, it is necessary to apply a positive voltage to the detector 8.
  • the electrons which pass through the specimen are detected by a detector 9 such as a Faraday cage.
  • the output signal from either of the two detectors 8 and 9 are selected by a switch 10', the selected signal being applied to the display means 12 via an amplifier 11.
  • the scanning signal generated by the scanning signal generating circuit 13 is fed into a deflecting means 14 forming part of the display means 12.
  • the scanning secondary electron image is observed.
  • the signal detected by the detector 9 is fed into the display means 12, the scanning transmission electron image is observed.
  • the incident electron beam is not affected by extraneous external electrical and magnetic disturbances. Further, since a high excitation magnetic lens is used, both chromatic and spherical aberrations are reduced considerably. Consequently, the irradiation spot of the incident electron beam is very fine and a high resolution scanning electron image is observed.
  • FIG. 2 shows ananalogous optical view of this embodiment.
  • the incident electron beam BB is focused by the condenser lens 2 and deflected by the deflecting means 5.
  • the deflected electron beam is focused and deflected by the electron lens 7 and irradiated on the specimen 6.
  • the incident electron beam is deflected as shown by BB That is to say, the incident electron beam scans the specimen ,over a wide field of vision.
  • FIG. 3 shows an electron microscope capable of observing both the normal transmission electron microscope image and the scanning electron image.
  • the objective lens 30 comprises a pole piece 31, a yoke 32 and a coil (not shown).
  • the pole piece 31 includes three ferromagnetic poles 33, 34 and 35 connected by a non-magnetic spacer 36, poles 33 and 34 constituting a gap, to be referred to as the first gap, and poles 34 and 35 constituting another gap to be referred to as the second gap.
  • a strong magnetic field is produced which acts as a lens in each of the two gaps when high excitation current is applied to the coil.
  • a specimen 37 is placed between the two gaps preferably in the object plane of the objective lens.
  • the field in the first gap focuses the parallel electron beam and the beam forming a reduction image of a crossover on the specimen 37.
  • Secondary electrons dispersed from the specimen 37 are confined by the pre-field and accelerated in the upper direction by an electrode 39 to which a positive voltage is fed from a power source 38.
  • the secondary electrons are spirally eccelerated in the prefield along the electron beam axis since the energy of the secondary electrons is weak and the said pre-field is strong.
  • the electrons which pass through the opening in the electrode 39 are deflected by optional magnetic field 40 (it is possible to eliminate this field as required) and directed towards a detector 41 located away from the electron beam axis.
  • the detector 41 comprises a grounded case 42, a photomultiplier 43, a light tube 44, an electrode 45 to which a positive voltage is fed from the power source 38 and a fluorescent screen 46.
  • the secondary electrons impinge on the fluorescent screen 46 and are changed into light signals. These signals then pass through the light tube 44 and are detected by the photomultiplier 43.
  • the output of the detector 41 is fed into a display means 47 such as a cathode ray tube.
  • the scanning signal is also fed into a deflecting means 47a of the display means 47.
  • the incident electron beam EB is scanned as BB BB and EB,,-.
  • the magnetic field produced by the first gap represented by the first lens 0L of the objective lens 30 focuses and deflects the incident electron beam.
  • the detector 41 is positioned in a higher plane than the specimen so as to detect the secondary electrons. It is equally possible of course to position the said detector in a lower plane than the specimen so as to observe the scanning transmission electron image.
  • the deflecting means 48 should be deactivated and the condenser lens (not shown) adjusted so that the incident electron beam focuses on the front focal plane of the first lens 0L This is necessary in orderto irradiate a parallel electron beam on the specimen 37.
  • the electron beam which passes through the specimen is focused on the plane P by the magnetic field produced by the second gap represented in FIG. 4 by the second lens 0L
  • the image, thus obtained, is magnified by a magnifying lens or lenses and projected onto a fluorescent screen.
  • FIG. 5 shows a modified embodiment of the electron microscope shown in FIG. 3.
  • a second electrode 50 is provided in place of the magnetic field 40 shown in FIG. 3.
  • the said electrode 50 is maintained at ground or negative potential so that the velocity of the secondary electrons accelerated by the first electrode 39 is reduced.
  • the said electrons are directed to the detector 41 by the electric field produced by the electrode 45.
  • FIG. 6 also shows a modified embodiment of the electron microscope shown in FIG. 3.
  • the objective lens 51 comprises two magnetic poles 52 and 53, a yoke 54 and a coil 55.
  • a permanent magnetic 56 is provided at the upper part of the lens.
  • a yoke plate 57, to which a magnetic pole 58 is fitted, is secured to the upper end of the permanent magnet 56. Consequently, the magnetic field produced by the magnetic poles 58 and 52 acts as the first lens and the magnetic field produced by the magnetic poles 52 and 53 acts as the second lens. It is possible to provide a magnetic excitation coil instead of the permanent magnet 56.
  • FIG. 7 shows another modified embodiment of the electron microscope shown in FIG. 3.
  • a pole piece 61 in an objective lens 60 comprises two magnetic poles 62 and 63.
  • the lens intensity to of the objective lens is expressed as follows:
  • FIG. 8 shows the magnetic distribution produced by the objective lens 60 under conditions of strong excitation.
  • the specimen 37 is placed near the maximum intensity area.
  • a magnetic field H produced in front of the specimen 37 acts as the first lens and a magnetic field H produced at the rear of the said specimen acts as the second lens.
  • the scanning electron image and the transmission electron microscope image are observed in the same way as in the embodiment shown in FIG. 3.
  • the detector 41 is located above the deflecting means.
  • the premagnetic field extends to the upper part of the deflecting means 48, the electrons are refocused along the optical axis by the said field and detected by the detector 41, even if the secondary electrons are deflected.
  • the advantage of this arrangement is that the deflecting means can be placed nearer the objective lens, thereby minimizing electron beam aberration produced by the deflection, and, by so doing, enabling the realization of a high resolution scanning electron microscope. Further, it is possible to spread the field of vision of the specimen and to locate attachments such as specimen heating and cooling devices with ease.
  • FIG. 10 shows another embodiment of this invention.
  • the deflecting means 48 for deflecting the incident electron beam is attached to the upper portion of the magnetic pole 62 of the objective lens 60
  • a movable stage 65 supporting a specimen holder 66 is mounted on the objective lens via ball bearings 64.
  • the detector 41 located in the specimen chamber 67 detects the secondary electrons emanating from the specimen holder 66.
  • the condenser lens 68 is mounted on the upper side of the specimen chamber 67.
  • An electron microscope comprising:
  • the objective lens comprises three magnetic poles, a yoke and an excitation coil, the first and second magnetic poles producing a magnetic field before the specimen, the second and third magnetic poles producing a magnetic field after the specimen.
  • An electron microscope according to claim 1 wherein the objective lens comprises two magnetic poles, a yoke and an excitation coil, the specimen being placed in the area of maximum magnetic field intensity produced by the two magnetic poles.
  • An electron microscope comprising:
  • An electron microscope according to claim 5 wherein the means for directing the secondary electrons comprises a magnetic field produced in the optical axis.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Electron Tubes For Measurement (AREA)
US00133894A 1970-04-18 1971-04-14 Scanning electron microscope Expired - Lifetime US3717761A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45033284A JPS4936496B1 (enrdf_load_stackoverflow) 1970-04-18 1970-04-18

Publications (1)

Publication Number Publication Date
US3717761A true US3717761A (en) 1973-02-20

Family

ID=12382218

Family Applications (1)

Application Number Title Priority Date Filing Date
US00133894A Expired - Lifetime US3717761A (en) 1970-04-18 1971-04-14 Scanning electron microscope

Country Status (5)

Country Link
US (1) US3717761A (enrdf_load_stackoverflow)
JP (1) JPS4936496B1 (enrdf_load_stackoverflow)
DE (1) DE2116289C3 (enrdf_load_stackoverflow)
GB (1) GB1308839A (enrdf_load_stackoverflow)
NL (1) NL147883B (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2392493A1 (fr) * 1977-05-26 1978-12-22 Philips Nv Microscope electronique
US4219732A (en) * 1978-04-07 1980-08-26 Nihon Denshi Kabushiki Kaisha Magnetic electron lens
FR2488044A1 (fr) * 1979-06-28 1982-02-05 Jeol Ltd Dispositif pour detecter des electrons secondaires dans un microscope electronique a balayage
FR2498011A1 (fr) * 1981-01-14 1982-07-16 Jeol Ltd Objectif magnetique a utiliser dans un microscope electronique a balayage
US4544846A (en) * 1983-06-28 1985-10-01 International Business Machines Corporation Variable axis immersion lens electron beam projection system
US4551625A (en) * 1982-09-30 1985-11-05 Siemens Aktiengesellschaft Spectrometer objective for particle beam measurement technique
EP0138610A3 (en) * 1983-10-17 1986-09-17 Texas Instruments Incorporated Electron detector
US4633085A (en) * 1984-04-17 1986-12-30 Jeol Ltd. Transmission-type electron microscope
US4658136A (en) * 1984-04-06 1987-04-14 Hitachi, Ltd. Secondary electron detecting apparatus
US4823005A (en) * 1986-02-20 1989-04-18 Texas Instruments Incorporated Electron beam apparatus
US4962306A (en) * 1989-12-04 1990-10-09 Intenational Business Machines Corporation Magnetically filtered low loss scanning electron microscopy
US20040238752A1 (en) * 2003-01-31 2004-12-02 Yuusuke Tanba Charged particle beam device

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3138926A1 (de) * 1981-09-30 1983-04-14 Siemens AG, 1000 Berlin und 8000 München Elektronenoptische anordnung fuer die hochaufloesende elektronenstrahl-messtechnik
FR2584234B1 (fr) * 1985-06-28 1988-12-09 Cameca Testeur de circuit integre a faisceau d'electrons
GB2201288B (en) * 1986-12-12 1990-08-22 Texas Instruments Ltd Electron beam apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1128107A (en) * 1965-06-23 1968-09-25 Hitachi Ltd Scanning electron microscope

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2392493A1 (fr) * 1977-05-26 1978-12-22 Philips Nv Microscope electronique
US4219732A (en) * 1978-04-07 1980-08-26 Nihon Denshi Kabushiki Kaisha Magnetic electron lens
FR2488044A1 (fr) * 1979-06-28 1982-02-05 Jeol Ltd Dispositif pour detecter des electrons secondaires dans un microscope electronique a balayage
FR2498011A1 (fr) * 1981-01-14 1982-07-16 Jeol Ltd Objectif magnetique a utiliser dans un microscope electronique a balayage
US4551625A (en) * 1982-09-30 1985-11-05 Siemens Aktiengesellschaft Spectrometer objective for particle beam measurement technique
US4544846A (en) * 1983-06-28 1985-10-01 International Business Machines Corporation Variable axis immersion lens electron beam projection system
EP0138610A3 (en) * 1983-10-17 1986-09-17 Texas Instruments Incorporated Electron detector
US4658137A (en) * 1983-10-17 1987-04-14 Texas Instruments Incorporated Electron detector
US4658136A (en) * 1984-04-06 1987-04-14 Hitachi, Ltd. Secondary electron detecting apparatus
US4633085A (en) * 1984-04-17 1986-12-30 Jeol Ltd. Transmission-type electron microscope
US4823005A (en) * 1986-02-20 1989-04-18 Texas Instruments Incorporated Electron beam apparatus
US4962306A (en) * 1989-12-04 1990-10-09 Intenational Business Machines Corporation Magnetically filtered low loss scanning electron microscopy
US20040238752A1 (en) * 2003-01-31 2004-12-02 Yuusuke Tanba Charged particle beam device
US6963069B2 (en) * 2003-01-31 2005-11-08 Hitachi High-Technologies Corporation Charged particle beam device
US20070235645A1 (en) * 2003-01-31 2007-10-11 Yuusuke Tanba Charged particle beam device
US7456403B2 (en) 2003-01-31 2008-11-25 Hitachi High-Technologies Corporation Charged particle beam device
US20090050803A1 (en) * 2003-01-31 2009-02-26 Yuusuke Tanba Charged particle beam device
EP1450391A3 (en) * 2003-01-31 2011-03-09 Hitachi High-Technologies Corporation Charged particle beam device
US7964845B2 (en) 2003-01-31 2011-06-21 Hitachi High-Technologies Corporation Charged particle beam device

Also Published As

Publication number Publication date
GB1308839A (en) 1973-03-07
JPS4936496B1 (enrdf_load_stackoverflow) 1974-10-01
DE2116289C3 (de) 1982-04-01
NL7103034A (enrdf_load_stackoverflow) 1971-10-20
DE2116289A1 (de) 1971-11-11
NL147883B (nl) 1975-11-17
DE2116289B2 (enrdf_load_stackoverflow) 1974-05-09

Similar Documents

Publication Publication Date Title
US5387793A (en) Scanning electron microscope
US6407387B1 (en) Particle beam apparatus
US6043491A (en) Scanning electron microscope
JP4037533B2 (ja) 粒子線装置
US4442355A (en) Device for detecting secondary electrons in a scanning electron microscope
US3717761A (en) Scanning electron microscope
US4714833A (en) Arrangement for detecting secondary and/or backscatter electrons in an electron beam apparatus
JPH0536371A (ja) 粒子線装置
JP2810797B2 (ja) 反射電子顕微鏡
EP0767482B1 (en) Particle-optical apparatus comprising a detector for secondary electrons
US6455848B1 (en) Particle-optical apparatus involving detection of Auger electronics
JP3170680B2 (ja) 電界磁気レンズ装置及び荷電粒子線装置
US5045705A (en) Charged particle beam apparatus with charge-up compensation
GB2081501A (en) Device for detecting secondary electrons in a scanning electron microscope
JP3514070B2 (ja) 走査電子顕微鏡
US6653632B2 (en) Scanning-type instrument utilizing charged-particle beam and method of controlling same
US3792263A (en) Scanning electron microscope with means to remove low energy electrons from the primary electron beam
US6710340B2 (en) Scanning electron microscope and method of detecting electrons therein
JP3432091B2 (ja) 走査電子顕微鏡
US5003172A (en) Auger spectrometry
US8957372B2 (en) Scanning electron microscope
US4097739A (en) Beam deflection and focusing system for a scanning corpuscular-beam microscope
JPH0955181A (ja) 走査電子顕微鏡
KR100711198B1 (ko) 주사형전자현미경
JP3494152B2 (ja) 走査形電子顕微鏡