JPS5624748A - Focal point detector for scanning type electron microscope - Google Patents

Focal point detector for scanning type electron microscope

Info

Publication number
JPS5624748A
JPS5624748A JP9735279A JP9735279A JPS5624748A JP S5624748 A JPS5624748 A JP S5624748A JP 9735279 A JP9735279 A JP 9735279A JP 9735279 A JP9735279 A JP 9735279A JP S5624748 A JPS5624748 A JP S5624748A
Authority
JP
Japan
Prior art keywords
output
focal point
operates
circuit
integrator
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.)
Pending
Application number
JP9735279A
Other languages
Japanese (ja)
Inventor
Osamu Yamada
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP9735279A priority Critical patent/JPS5624748A/en
Publication of JPS5624748A publication Critical patent/JPS5624748A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02Details
    • H01J37/21Means for adjusting the focus

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)

Abstract

PURPOSE:To improve the detection precision of a focal point by providing a means which operates a difference in the value when the focal length of an objective lens is modulated into positive and negative ones with a modulator. CONSTITUTION:When the first scanning of electron beam is completed, a sample and hold circuit (SH) 23 operates and the output of an integrator 22, i.e., the output of the signals integrated during this scanning period from an input signal operation circuit 21 is stored in a circuit SH 23. Subsequently, the integrator 22 is reset and integrates the output of the circuit 21 during the second scanning period. When this scanning is completed, the output of the integrator 22 is stored in SH 24. A subtractor 25 operates a difference between SH 23 and 24. When the output has been adjusted. SH 24 operates the value and displays it on a center-zero meter 19 through SH 26. On the other hand, when the focal point of an objective lens is optimum, insufficient, and excessive, since the output of SH 26 becomes zero, positive, and negative, respectively, adjust the meter 19 so as to read zero, repeating the above operation. This improves the detection precision of the focal point.
JP9735279A 1979-08-01 1979-08-01 Focal point detector for scanning type electron microscope Pending JPS5624748A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9735279A JPS5624748A (en) 1979-08-01 1979-08-01 Focal point detector for scanning type electron microscope

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9735279A JPS5624748A (en) 1979-08-01 1979-08-01 Focal point detector for scanning type electron microscope

Publications (1)

Publication Number Publication Date
JPS5624748A true JPS5624748A (en) 1981-03-09

Family

ID=14190088

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9735279A Pending JPS5624748A (en) 1979-08-01 1979-08-01 Focal point detector for scanning type electron microscope

Country Status (1)

Country Link
JP (1) JPS5624748A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59108251A (en) * 1982-12-10 1984-06-22 Hitachi Ltd Astigmatism correction method for electron optical system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5264865A (en) * 1975-11-25 1977-05-28 Shimadzu Corp Focus detection unit of electronic line scanning-type image equipment

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5264865A (en) * 1975-11-25 1977-05-28 Shimadzu Corp Focus detection unit of electronic line scanning-type image equipment

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59108251A (en) * 1982-12-10 1984-06-22 Hitachi Ltd Astigmatism correction method for electron optical system

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