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
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
  • H01J37/147—Arrangements for directing or deflecting the discharge along a desired path
  • H01J37/1471—Arrangements for directing or deflecting the discharge along a desired path for centering, aligning or positioning of ray or beam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K15/00—Electron-beam welding or cutting
  • B23K15/0013—Positioning or observing workpieces, e.g. with respect to the impact; Aligning, aiming or focusing electronbeams
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K15/00—Electron-beam welding or cutting
  • B23K15/0046—Welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K15/00—Electron-beam welding or cutting
  • B23K15/02—Control circuits therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K15/00—Electron-beam welding or cutting
  • B23K15/06—Electron-beam welding or cutting within a vacuum chamber
• • 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
  • H01J37/21—Means for adjusting the focus
• • 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
  • H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
  • H01J37/315—Electron-beam or ion-beam tubes for localised treatment of objects for welding
• • 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
  • H01J2237/15—Means for deflecting or directing discharge
  • H01J2237/1501—Beam alignment means or procedures

Definitions

• a beam generated in a Cathode- Wehnelt-Electrode-Anode system is formed and deflected, respectively, by magnetic fields, in which case the focusing of the beam in the center of a current conducting coil has an important influence.
• the beam passes centrally through the focusing coil, so that rotationally symmetric fields influence the beam and only the position of the focus plane is changed in the focusing. If this is not the case, the beam is deflected in addition to the change of the focus of the beam, so that the impact point of the beam on a work piece "wanders" by varying the focusing coil currents.
• EB electron beam
• a planar surface arranged perpendicularly to the electron beam direction.
• This can be a workpiece plane, or can also be a separate test body; advantageously a special screen can be used, e.g., a luminescent screen having a surface with a luminescent coating.
• a luminescent screen is used as an illustrative example in the following. An illuminated point is formed on the screen by a beam focussed exactly on its surface. The point expands with increasing defocusing, and vice versa.
• a lateral "wandering" of the luminescent image on the screen is generated in addition to the above- described “breathing".
• the "wandering” can be eliminated by correctly aligning the centering currents (or, with a less effective system, can be minimized).
• a disadvantage of this method is the necessity of a significant installation of apparatuses.
• Such a measurement sensor apparatus cannot be installed permanently, in particular, in short cycle time production machines which usually have chambers with small dimensions, and, therein, complicated work piece mounting devices. Moreover, it may be quickly contaminated by effects of the operation of the machine. In order to be able to insert the sensor when necessary, it is not only required to have the necessary (and often unavailable) free workspace, but appropriate mountings and an electrical connection to the outside are also required.
• US 4,160,150 describes an electron beam welding apparatus adapted to reduce the drift of the fused material flowing from the welding zone by constantly changing the status of the focusing of the electron beams.
• US 7,075,076 B2 describes an inspection unit adapted to capture images of an inspection area by various focusing adjustments.
• the present invention provides an improved technique for adjusting an electron beam apparatus.
• the frequency is chosen to be so high that a type of stroboscope effect is produced, so that the eye of the operator can no longer perceive the breathing. Then, a resulting light effect can be seen that spans the entire surface excited by the through-focusing.
• This excited surface typically appears to be dumbbell-shaped (two-dimensional), wherein the spheres, more specifically circular surfaces, are formed at the turning points of the wandering movement of the beam.
• the "bar" of the dumbbell is shown in the middle and is comparatively thin. Therein lies the focus.
• the described dumbbell image is deformed when the centering currents are changed.
• the dumbbell is turned and lengthened or shortened in the image plane. This happens in such a way that the operator can immediately, effortlessly, and, thanks to the stroboscope effect, almost statically evaluate the effects of his changes.
• Fig. 3 a principal sketch of an embodiment of an adjusting unit
• Fig. 1 shows an electron beam apparatus that comprises an electron beam generator 1 and an adjusting and focusing unit 2.
• the electron beam generator 1 generates an electron beam that propagates along an electron beam axis 5.
• the adjusting and focusing unit 2 is arranged on the electron beam axis 5 in the beam direction downstream of the electron beam generator 1.
• the electron beam generator 1 comprises, in the present embodiment, a cathode 11, an electrode 12, e.g., a Wehnelt electrode, and an anode 13.
• the adjusting and focusing unit 2 comprises, in the present embodiment, an adjusting unit 21 and a focusing unit 22. In the present embodiment, the adjusting unit 21 is arranged between the electron beam generator 1 and the focusing unit 22.
• Fig. 3 shows an embodiment of the adjusting unit 21, which comprises a first adjusting coil 21 1 and a second adjusting coil 213.
• the first adjusting coil 211 comprises adjusting current contacts 212 and a second adjusting coil 213 comprises adjusting current contacts 214.
• the first adjusting coil 211 comprises, in the present embodiment, two coils that are arranged opposite to each other, 21 Ia (as shown on the left side of Fig. 3) and 21 Ib (as shown on the right on the side of Fig. 3).
• One of the adjusting contacts 212 is connected to the coil 211a, and the other adjusting current contact 212 is connected to the oppositely-arranged coil 211b.
• the adjusting unit 21 shown in Fig. 3 is, in the present embodiment of the electron beam unit, arranged in such a way that the electron beam axis 5 extends perpendicularly to the plane of Fig. 3 and through the area inside the coils 21 Ia, 21 Ib, 213a and 213b.
• the intervals between the respective coils 211a, 21 Ib, 213a and 213b and the electron beam axis 5 are all the same.
• the next (e.g., loaded in the changing cycle) workpiece can be directly subjected to the processing.
• the electron beam is then optimally centered.
• the luminescent screen is normally removed beforehand from the machine, because the volume of the working chamber is often so small that the necessary space for storing it, for example, for pivoting it out of the way, is not available. The removal of the luminescent screen from the machine also prevents the luminescent screen from being contaminated during the use of the electron beam unit.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Electron Sources, Ion Sources (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2008
  • 2008-02-15 DE DE200810009410 patent/DE102008009410B4/de not_active Revoked
• 2009
  • 2009-02-10 WO PCT/EP2009/000919 patent/WO2009100877A1/en active Application Filing
  • 2009-02-10 EP EP09710101A patent/EP2253006A1/de not_active Withdrawn

Non-Patent Citations (1)

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