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
  • H01J37/18—Vacuum locks ; Means for obtaining or maintaining the desired pressure within the vessel
• • 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
  • H01J2237/2602—Details
  • H01J2237/2605—Details operating at elevated pressures, e.g. atmosphere

Definitions

• the present invention relates to scanning electron microscopes and, more particularly, to an in situ operating scanning electron microscope.
• scanning electron microscopes has experienced rapid development in recent years due to their flexibility of use, in combination in particular with cathode ray display screens, and their extremely appreciable observation performance, in particular with regard to the depth of field
• These characteristics make scanning electron microscopes particularly advantageous, on an industrial level, for the control of surfaces of structural or operational parts, in particular for the control of manufacturing processes or the study of deformations of surfaces during stress tests -
• the study of such surfaces was done by conventional optical methods using magnifying glasses or optical microscopes, with the associated drawbacks of low magnification, and especially of limited depth of field. It therefore appears particularly plausible to use scanning electron microscopes for such checks because of their advantages mentioned above.
• an observation technique has been proposed using an electron microscope, using a small vacuum intermediate enclosure connected to a powerful pumping device and opening out in line with the area to be observed by a very small aperture diaphragm. (of the order of 30 microns) and of small thickness, in order to limit as much as possible the air leakage rate to be permanently compensated by the pumping device.
• the technique thus proposed suffers from numerous limitations, notably due to the very limited "field of observation, due to the microscopic dimension of the diaphragm, to the non-homogeneity of the vacuum at the optical axis as well as to the diffusion of electrons backscattered by the object resulting in poor quality images.
• the object of the present invention is precisely to overcome these drawbacks by proposing a set of scanning electron microscope operating in situ, of light and transportable construction, which can be placed directly on the object to be examined without any particular preparation for it, in particular allowing direct observation of the object in question in its natural environment, making it possible to obtain strong magnifications with a significant depth of field (for example of the order of a thousand times greater than with an optical microscope) for a rapid, flexible and non-destructive study in situ, for example of airplane wings, or for the control of parts machined or worked with precision, such as glass lenses or mirrors of optical systems.
• a significant depth of field for example of the order of a thousand times greater than with an optical microscope
• the set of electron microscope to scanning in situ operation comprising a column of unitary electron microscope, means of connection to a command and control installation, of the microscope and of a pumping installation, comprises a means of supporting the column, connected to the lower part thereof, and defining an interior chamber having a lower open part intended to be placed in sealed support on a peripheral surface integral with the area to be observed, means being provided for putting the interior chamber into communication with a transportable pumping.
• the support means comprises a pressure-resistant peripheral wall or skirt defining the interior chamber and flexible sealing means delimiting the lower open part of the chamber and intended to be applied to the support surface to be observed.
• the single figure is a schematic view of a scanning electron microscope assembly in situ operation according to the present invention positioned in sealed support on a surface to be observed.
• the scanning electron microscope assembly with in situ operation essentially comprises an electron microscope column 1, of small dimensions and of reduced weight, connected to an electronic command and control installation. adequate 2, a column support means 3 defining an interior chamber 4, connected as well as the column 1, to a powerful and portable pumping device 40.
• the column 1 comprises a hermetic tubular frame 5 containing, successively , an electron gun 6, a stage 7 of two condensers 7 1 and 7 2 a stage of objective lens 8 with a stigmator 9 and coils scanning 10 in a tubular conduit 11 extending to the vicinity of the bottom of a frustoconical cover 12 converging downwards, closing the column 1 and provided with a central opening 13 for passage of the electron beam around which the annular electron detector 14 concentric to the optical axis 15 of column 1.
• the support means 3 of the column 1 comprises a wall or peripheral skirt with resistance in shape 16, resistant to pressure, for example a stainless steel ferrule, defining the interior chamber 4, in which the cover projects. frustoconical lower 12 and on the edge of the open end of which is fixed a peripheral elastic seal 17, for example of solid or selectively inflatable elastomeric material.
• the support means further comprises a height adjustment system or jacks 18, 18 ′, making it possible to precisely regulate the distance between the detector 14 and the area to be observed A from the surface 19 ′ of the surface over a determined range. body 19 to be studied.
• a connector 20, mounted in the wall 16, allows the connection of the detector 14 to the command and control installation 2.
• the wall 16 also comprises, laterally, a sleeve 21 for connection to the pumping device 4.
• the column 1 is connected to the upper end of the support wall 16 by a ball joint system 22, for example with cooperating t ⁇ flon toroidal surfaces, the sealing at the level of the ball joint 22 being ensured by a flexible membrane 23 in a metal alloy that is known under the name "Tombac" sealingly connecting the upper part of the wall 15 to an adjacent crown of the frustoconical cover 12.
• a ball joint system 22 for example with cooperating t ⁇ flon toroidal surfaces, the sealing at the level of the ball joint 22 being ensured by a flexible membrane 23 in a metal alloy that is known under the name "Tombac" sealingly connecting the upper part of the wall 15 to an adjacent crown of the frustoconical cover 12.
• the microscope column 1 is for example of the MIEL bis type developed by the CNRS electronic optics laboratory in Toulouse, operating under a low voltage of the order of 10 to 15 kilovolts.
• the wall 16 of the support means can be extended radially inwards by a crown, itself terminated by the watertight seal 17, to limit the opening of the interior chamber 4.

Landscapes

• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Analysing Materials By The Use Of Radiation (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9254838

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (14)

Citations (4)

Family Cites Families (2)

• 1981
  • 1981-02-04 FR FR8102152A patent/FR2499314A1/fr active Granted
• 1982
  • 1982-02-02 DE DE8282400176T patent/DE3265695D1/de not_active Expired
  • 1982-02-02 US US06/432,918 patent/US4516026A/en not_active Expired - Fee Related
  • 1982-02-02 JP JP57500480A patent/JPS58500386A/ja active Pending
  • 1982-02-02 EP EP19820400176 patent/EP0057646B1/fr not_active Expired
  • 1982-02-02 WO PCT/FR1982/000021 patent/WO1982002796A1/en unknown

Patent Citations (4)

Non-Patent Citations (1)

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