Abstract: A charged particle beam expander increases a diameter of a charged particle beam while increasing uniformity of an area energy distribution thereof. The charged particle beam expander has a first linear optics section receiving the charged particle beam from a particle accelerator and for forming the charged particle beam to have a generally circular cross-section and a non-linear optics section receiving the charged particle beam from the first linear optics section and for redistributing charged particles from a periphery of the charged particle beam toward a core thereof. The charged particle beam expander also has a second linear optics section receiving the charged particle beam from the non-linear optics section, the second linear optics section for increasing the diameter of the charged particle beam and for imaging the charged particle beam onto the target.

Abstract: An improved particle lens has an axis that is shifted to follow the central ray of the beam as it is deflected through the lens creating, in effect, a variable curvilinear optical axis for the lens and introducing aberrations having depending on the object size and the distance off the lens symmetry axis. These aberrations are corrected by a set of correction elements generating compensating aberrations of the same type, comprising at least one wire pair perpendicular to the system axis and carrying fixed currents to introduce a gradient in the field, together with three coils centered on the system axis to cancel a bias field introduced by the wire pair.

Abstract: Electromagnetic deflectors and methods for their manufacture are disclosed. The excitation coils inside such deflectors can be situated relative to each other and to an optical axis with a high degree of accuracy and precision. A pair of loop-shaped channels are formed opposite each other in the sides of a cylindrical insulating cylinder. An electrically conductive material is embedded in the channels to form a set of opposing coils operable to deflect a charged particle beam passing axially through the cylinder in one dimension. Multiple cylinders each comprising a set of opposing coils can be concentrically assembled to provide, e.g., a biaxial deflector operable to deflect the beam in an X-dimension and a Y-dimension. In such a biaxial deflector, the sets of coils are arranged perpendicular to each other. The cylinder(s) is placed concentrically inside a cylindrical outer casing made of a ferromagnetic material such as ferrite to make an electromagnetic deflector.

Abstract: There is disclosed a high-resolution magnetic-electrostatic compound objective lens for use in a scanning electron microscope, the objective lens having reduced spherical aberration and chromatic aberration. The lens comprises a substantially conically-shaped magnetic pole piece, a coil wound along the inner surface of the magnetic pole piece, a hollow insulator disposed along the inner surface of the coil and a high-resistivity film disposed along the inner surface of the insulator. When the coil is energized, an axially symmetrical magnetic field is produced inside the magnetic lens. The obtained axial magnetic flux density distribution has a peak near the bottom end of the magnetic pole piece. The principal plane of the magnetic lens is brought close to the specimen and results in smaller aberrations.

Abstract: A composite magnetic lens and deflector for particle beam optical systems has a concentric gap and concentric conical lower pole pieces arranged to allow more accurate magnetic deflection. The flux generated by a solenoidal lens coil is shared by magnetically soft inner and higher saturation flux outer pole pieces to minimize saturation effects, while the flux generated by internal deflection coils is confined to magnetically soft inner pole pieces that minimize flux leakage and associated eddy current settling effects. Shielding rings further contain leakage flux. The inner magnetic circuit is mounted and adhesively bonded to radial flexures to minimize thermal expansion drifts.

Abstract: To improve the throughput of an exposure system, the setting time during a step change in the output of an amplifier is reduced by switching resistance between the amplifier and a deflector. A glitch waveform generated during a step change in the output of a D/A converter at the preceding stage of the amplifier is anticipated and is cancelled out with a correction waveform. After the output of the D/A converter has settled, this output is sample-held and the step change is interpolated with a smoothing circuit. The deflection area is increased by positioning an electrostatic deflector offset around the optical axis relative to another electrostatic deflector, and the response speed of the main deflection is improved by adding auxiliary deflection coils of one or two turns. The alignment time is reduced by combining the coordinate conversion in the wafer area and in the chip area.

Abstract: A charged particle lens has an axis that is shifted to follow the central ray of the beam as it is deflected through the lens creating, in effect, a variable curvilinear optical axis for the lens and introducing aberrations having depending on the object size and the distance off the lens symmetry axis. These aberrations are corrected by a set of coil pairs tilted with respect to the system axis, which generate compensating aberrations of the same type.

Abstract: A deflection magnetic system and method are provided to deflect an electron beam through a predetermined angle while maintaining a circular cross-section for the electron beam. A plurality of spaced magnetic fields are provided to deflect the electron beam through angles less than the total predetermined angle, but the total angle is achieved when the beam passes through the last magnetic field. Magnetic shields are provided between the spaced magnetic fields to absorb any undesired leakage magnetic flux.

Abstract: A magnetic system for producing a magnetic field having static and high frequency time-varying components comprising: two magnetic poles defining a gap therebetween, the poles being formed with electrically insulating material for confining any high frequency induced eddy currents to limited values in local paths in the poles; an ac coil associated with the magnetic poles for producing a time-varying magnetic field in the gap; a magnetic structure including a yoke and two cores which are respectively coupled to the two poles, the magnetic structure being formed of solid material, with a high magnetic saturation level; and dc coils associated with the cores of the magnetic structure for producing a static magnetic field in the gap. The magnetic system are used for magnetically scanning an ion beam and an ion implantation system, both of which are based on the above system, as well as a magnetic system useful for magnetic resonance imaging applications.

Abstract: An improved particle lens has an axis which is shifted to follow the central ray as it is deflected through the lens creating, in effect, a variable curvilinear optical axis for the lens. The variable curvilinear optical axis is created for the lens so that the axis varies proportionally to the magnitude of the beam deflection. The optical axis of the lens is shifted by applying a uniform field to the lens to cancel the first term of the radial field with a function that is dependent on the position along the z-axis. This function is the trajectory of the central ray of the electron beam.

Abstract: A charged particle beam transferring apparatus includes a pair of electro-magnetic lenses spaced apart in the direction of the optical axis. Each electro-magnetic lens consists of a coil and core made of magnetic material and having two magnetic poles. The core of at least one of the electro-magnetic lenses is made of ferrite. An insulating member supports the two magnetic poles of the core of the at least one of the electro-magnetic lenses between its two magnetic poles.

Abstract: A border of a circular specimen defining a high contrast feature is imaged. Multiple border portions are sampled at a magnification showing each portion as a straight edge. For alignment a location indicator signal is generated at each of minimum and maximum focal range. Image translation is detected from the two signals, and alignment automatically adjusted. The process repeats for subsequent border portions at a 90.degree. interval until image translation falls for a sample is less than a threshold. For astigmatism correction border portions are sampled about the entire specimen circumference at a 30.degree. interval. An axis of beam distortion is identified based upon a maximum image translation axis among the samples. Distortion is adjusted along such axis. Then, astigmatism connection signal strength is indexed and astigmatism correction is repeated iteratively until correction for a current iteration is less than a given threshold.

Abstract: An electron energy filter is structured by superposing a pair of yokes having electron beam passage holes and pole pieces on each side facing each other so as that the pole pieces are positioned facing each other with a certain space in between, and the electron energy filter is mounted in a transmission electron microscope to obtain a stable elemental mapping image.

Abstract: A method and apparatus for a charged particle scanning system and an automatic inspection system, including wafers and masks used in microcircuit fabrication. A charged particle beam is directed at the surface of a substrate for scanning that substrate and a selection of detectors are included to detect at least one of the secondary charged particles, back-scattered charged particles and transmitted charged particles from the substrate. The substrate is mounted on an x-y stage to provide at least one degree of freedom while the substrate is being scanned by the charged particle beam. The substrate is also subjected to an electric field on it's surface to accelerate the secondary charged particles. The system facilitates inspection at low beam energies on charge sensitive insulating substrates and has the capability to accurately measure the position of the substrate with respect to the charged particle beam.

Abstract: A normal conducting bending electromagnet having: a pair of pole pieces having respective pole piece faces, said pole pieces being; disposed with the pole piece faces thereof facing each other with a substantially constant gap therebetween; a magnetic field for forming a charged particle beam arc orbit, being generated in the gap between the pole pieces. A yoke coupled to the pole pieces for forming a closed magnetic circuit with the gap, and a pair of coils is provided for generating a magnetomotive force and generating magnetic fluxes in the magnetic circuit. At least one side wall of each of the pole pieces is slanted or stepped along a virtual slanted plane; along the magnetic path of the pole piece so as to gradually broaden the cross sectional area of the pole piece at the plane perpendicular to the magnetic path from the gap toward the yoke, the slanted side wall or the virtual slanted plane; having a slant angle in the range from 30.degree.

Abstract: A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.

Abstract: An apparatus employs two spaced apart dipole magnets. An ion beam containing carbon of mass 2, 13 and 14 is focused by an Einzel lens and is directed into a first dipole magnet. The first magnet causes the beam to bend approximately 70 degrees, which separates the mass 12, 13 and 14 ions while at the same time focusing them in the X direction or deflection plane. The ions exit the first dipole magnet and pass through a blanking plate which can selectively remove one or two of the beams of mass 12, 13 and 14 ions. After leaving the first bending magnet, the mass 12 and 14 beams pass through a steering device so the trajectories of the mass 12 and 14 ions are deflected a few degrees to bring them parallel to the mass 13 ion beam. The parallel ion beams next pass through an electrostatic slot lens which focuses the beams in the direction out of the bending plane. After passing through the slot lens, the mass 12 and 14 beams are deflected in like amount to the deflection at the first steering device.

Abstract: A deflection yoke for controlling a charged particle beam, such as an electron beam, comprises a toroidal core, which may be ferromagnetic material or not, a major yoke winding, and a minor yoke winding. The major and minor yoke windings are arranged to minimize mutual inductance between the major winding and the minor winding. The major yoke winding is a toroidal winding about the core and said minor yoke winding is a saddle winding on said core. In one embodiment, the minor winding comprises a first saddle winding inside the toroidal core and a second saddle winding outside the toroidal core. A reactive shunt is connected across the first saddle winding or the second saddle winding. The reactive shunt provides a shunt current path to balance flex contribution in the core from the first and second saddle windings so that excitation of the minor yoke does not induce any excitation in the major yoke.

Abstract: A scanning system (25) for controlling a scanning servo (28,30) includes a scanning signal generator (50) which generates (51) a series of square wave scan signals, a pulse signal generator which generates (52) a pattern of pulses having short durations relative to the scan signal from the first generator, the generators being synchronized, and the scan signals and pulses then being separately applied to the scanner servo (30) to control it such that the resulting scanning behavior of the servo corresponds to the scan signals modified by the pattern of pulses.

Abstract: A mass recombinator comprises a source of negative ions to be analyzed. These negative ions are accelerated to roughly the same moderate kinetic energy and electrostatically focused to a substantially parallel beam which enters the magnetic field of a dipole magnet at an angle of incidence. The field of the dipole magnet is designed to deflect a substantially parallel beam of negative ions having the same energy and entering at a specified angle of incidence in such a manner that it describes a loop of approximately 264.6 degrees, forming a mass spectrum at a position inside the magnet after deflection of approximately 132.3 degrees. The beam exits the field as a parallel beam substantially where it entered, independent of the mass of the ions.

Abstract: A magnetic system for uniformly scanning an ion beam comprising a magnetic structure having poles with associated scanning coils and respective pole faces that define therebetween a gap through which the ion beam passes; and a magnetic circuit for producing in the gap a magnetic field of sufficient magnitude to prevent the occurrence of a recently observed plasma effect in which the transverse cross-section of the ion beam substantially fluctuates in size while the ion beam is being scanned across the selected surface.

Abstract: The magnetic axis of a stigmation yoke is varied from the mechanical axis of the stigmation yoke by differentially driving pairs of coils in a quadrupole configuration with currents which differ from a nominal stigmation current by approximately equal amounts, applied in opposite senses. Set-up procedures for electron beam deflection systems, such as in e-beam tools, are automated by emulating manual procedures in combination with electric alteration of the magnetic axis of the stigmator yoke. Stigmation errors can also be collected under automated set-up procedure control to allow dynamic correction of astigmatism in electron beam deflection system. Electrically variability of the magnetic axis of the stigmator yoke also allows the placement of the stigmator yoke at a position in the electron optical column other than prior to deflection stages as well as improved freedom from positional and aberrational errors.

Abstract: A charged particle beam line is formed with magnetic optics that manipulate the charged particle beam to form the beam having a generally rectangular configuration to a circular beam cross-section having a uniform particle distribution at a predetermined location. First magnetic optics form a charged particle beam to a generally uniform particle distribution over a square planar area at a known first location. Second magnetic optics receive the charged particle beam with the generally square configuration and affect the charged particle beam to output the charged particle beam with a phase-space distribution effective to fold corner portions of the beam toward the core region of the beam. The beam forms a circular configuration having a generally uniform spatial particle distribution over a target area at a predetermined second location.

Abstract: An electron beam system for direct writing applications combining the parallel throughput of a projection system and the stitching capability of a probe-forming system employs an electron gun to illuminate an initial aperture uniformly, a first set of controllable deflectors to scan the beam over the reticle parallel to the system axis, impressing the pattern of a subfield of the reticle in each exposure, in which a first variable axis lens focuses an image of the initial aperture on the reticle, a second variable axis lens collimates the patterned beam, a second set of controllable deflectors to bring the beam back to an appropriate position above the wafer, and a third variable axis lens to focus an image of the reticle subfield on the wafer, together with correction elements to apply aberration corrections that may vary with each subfield, thereby providing high throughput from the use of parallel processing of the order of 10.sup.

Abstract: The invention relates to an electron energy filter for electron microscopes as well as to an electron microscope equipped with such a filter. The filter comprises three sector magnets with the deflection field in the first sector magnet being homogeneous. The deflection field in each of the two other sector magnets is an inhomogeneous gradient field. To generate the gradient field, the pole pieces of the two other sector magnets have the form of segments of truncated double cones. The electron beam passes the first homogeneous sector magnet twice. Multipole elements are arranged in front of, behind and between the three sector magnets. The filter has a large dispersion also for high-energy electrons while at the same time providing a compact configuration. All second-order aberrations and the significant second-rank aberrations are corrected by means of the multiple elements.

Abstract: An imaging symmetrical energy filter (of the .OMEGA.-type) comprising two pairs of sector magnets (1), (2), (3), (4) for an electron microscope. The second-order chromatic aberration is corrected by arranging the two pairs of sector magnets {(1),(4) and (2),(3)} further apart. This enables suitable arrangement of the coils to generate correction hexapole fields, so that the chromatic error is even completely eliminated. Moreover, correction of the third-order aperture aberration is also possible by constructing the hexapole coil (9) in the symmetry plane also as an octupole coil. Further correction of this third-order aberration is achieved by applying an octupole field (5) directly at the entrance of the first sector magnet (1) and an octupole field (13) directly at the exit of the fourth sector magnet (4).

Abstract: A device for reducing the magnetic field, leaked from an electromagnetic lens, in the sample position of a scanning electron microscope, a sample is mounted on a sample cassette which is made of a material having high magnetic permeability, and a head portion of an electron optical system which is made of a material having high magnetic permeability is arranged on the sample side. A window for passing a probe beam therethrough is provided in a wall surface of the electron optical system. Both the sample cassette and the electron optical system head portion surround the sample to constitute a magnetic shield.

Abstract: An electron lens comprising a first exciting coil, a second exciting coil, a casing for encompassing the first and second exciting coils, and an excitation control apparatus for controlling the excitation state of at least the first exciting coil independently of the second exciting coil. The excitation control apparatus independently controls currents applied to the first and second exciting coils, respectively. At this time, exothermy of each coil can be kept constant and thermal deformation of the casing can be prevented by keeping the sum of the absolute values of the currents applied to the coils.

Abstract: A magnetic deflection system for scanning an ion beam over a selected surface comprising: a magnetic structure having poles with respective scanning coils and respective pole faces that define therebetween a gap through which the ion beam passes; a primary current source coupled to the scanning coils adapted to apply to the scanning coils an excitation current to generate a substantially unipolar oscillatory magnetic field in the gap that alternates in polarity as a function of time to cause scanning of the ion beam, the substantially unipolar magnetic field having a magnitude sufficiently greater than zero to prevent the transverse cross-section of the ion beam from substantially fluctuating in size while the ion beam is being scanned across the selected surface.

Abstract: An electron beam apparatus comprises an electron beam source, a unit for irradiating an electron beam on a specimen, a detector for secondary electrons, an electrode for generating an electric field sufficient to draw out secondary electrons in a recess in the specimen from the recess, and a unit for generating a magnetic field for focusing secondary electrons drawn out of the recess. With this construction, the secondary electrons drawn out of the recess by the electric field reach the detector without being attracted by the electrode. By adopting this construction, a contact hole of high aspect ratio formed in a semiconductor device and having a small diameter and a large depth can be observed.

Abstract: A scanning electron microscope capable of producing a stable image even if an automated focusing operation is being performed. The microscope has a secondary electron detector, a vertical scanning signal generator, and an image memory connected with a CRT. The output signal from the detector is supplied to the image memory via an amplifier and an A/D converter and also to an integrator via a filter circuit and an absolute value circuit. The specimen is scanned to produce an image and is substantially simultaneously scanned to gather data for adjusting the focus by stepwise adjusting the objective lens current. The stepwise adjustment of the objective lens takes place only during scanning to gather data.

Abstract: A magnetic electron lens for use in charged particle beam-applied apparatuses such as electron microscopes, the lens having concave lens characteristics in a geometric-optical sense. The magnetic concave lens of the invention comprises a first and a second magnetic field generating coil arranged in the propagating direction of the charged particle beam, and a first and a second magnetic shielding plate made of a superconductor each and furnished so as to enclose the first and the second magnetic field generating coils. The first magnetic shielding plate shields the magnetic field generated above the first magnetic field generating coil, and the second magnetic shielding plate shields the magnetic field generated under the second magnetic field generating coil. This setup constitutes a magnetic electron lens that is concave in terms of geometric-optical lens characteristics.

Abstract: Deflection apparatus is shown for high perveance ion beams, operating at 20 Hz fundamental and substantially higher order harmonics, having a magnetic structure formed of laminations with thickness in range between 0.2 and 1 millimeter. Additionally, a compensator is shown with similar laminated structures with resonant excitation circuit, operating at 20 Hz or higher, in phase locked relationship with the frequency of the previously deflected beam. Furthermore, features are shown which have broader applicability to producing strong magnetic field in magnetic gap. Among the numerous important features shown are special laminated magnetic structures, including different sets of crosswise laminations in which the field in one lamination of one set is distributed into multiplicity of laminations of the other set of coil-form structures, field detection means and feedback control system, cooling plate attached in thermal contact with number of lamination layers.

Abstract: The magnetic axis of a stigmation yoke is varied from the mechanical axis of the stigmation yoke by differentially driving pairs of coils in a quadrupole configuration with currents which differ from a nominal stigmation current by approximately equal amounts, applied in opposite senses. Set-up procedures for electron beam deflection systems, such as in e-beam tools, are automated by emulating manual procedures in combination with electrical alteration of the magnetic axis of the stigmator yoke. Stigmation errors can also be corrected under automated set-up procedure control to allow dynamic correction of astigmatism in electron beam deflection system. Electrically variability of the magnetic axis of the stigmator yoke also allows the placement of the stigmator yoke at a position in the electron optical column other than prior to deflection stages as well as improved freedom from positional and aberrational errors.

Abstract: An electron beam writing system which permits a relatively low voltage to be applied to perform high speed focus correction with high accuracy. The electron beam writing system includes a focus corrector arranged inside a lens which provides the largest product of the magnification factors of the lens and all succeeding lenses and the optical path length of the lens at issue. Thus, the electron beam provides high sensitivity and a small change in the magnification ratio due to the correction.

Abstract: A charged particle beam exposure method for deflecting a charged particle beam in a deflection system which includes electromagnetic deflection coils, includes the steps of (a) controlling the deflection system based on deflection data, and (b) generating heat at least a vicinity of the electromagnetic deflection coils so as to compensate for a change in heat generated from the electromagnetic deflection coils.

Abstract: In a method of focusing a beam of charged particles by means of a magnetic field which is generated by a current flowing through a plasma volume contained by an insulating tube extending between two opposite annular electrodes which produce the current in a pulsed form, the insulating tube has, with respect to the cross-section of the particle beam which passes therethrough a diameter so selected that the tube wall is disposed adjacent the limit of the penetration depth of the magnetic field into the plasma as constricted solely by the magnetic field generated between the electrodes.

Abstract: A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0.degree. to 360.degree. and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment.

Abstract: An improved scanning electron microscope is disclosed which includes a compact, replaceable electron beam emitter assembly and concentric liner tubes. The concentric liner tubes extend through a central portion of electromagnetic lenses for forming an evacuated path for the electron beam. An outer sealing jacket is provided for forming a vacuum seal with the column assembly sufficient to maintain a vacuum within the outer sealing jacket. A conductive inner liner tube positioned within the outer sealing jacket is adapted to have the electron beam pass therethrough. The inner liner tube provides supports for spray baffles and/or beam shaping orifices. The improved electron beam emitter assembly within the gun assembly includes a filament clamped between a front plate and a back plate by clamping screws. The clamping screws additionally hold an adjustable grid against the front plate.

Abstract: A magnetic immersion field emission electron gun has a vacuum vessel having a central axis in a predetermined direction, a cathode arranged along the central axis of the vacuum vessel for generating an electron beam, an anode for forming an electron beam path by accelerating a generated electron beam in the central axis direction, an electrostatic lens arranged between the cathode and anode for generating an electric field which focuses an accelerated electron beam toward the central axis, a magnetic field generating element arranged around the electron beam path for generating a magnetic field for focusing the electron beam in order to preventing a diameter of the electron beam from expansion by an aberration of the electrostatic lens, and a moving mechanism for moving the magnetic field generating element at a position where a peak point of a strength of the magnetic field generated by the magnetic field generating element coincides with a portion where the aberration of the electrostatic lens becomes most

Abstract: A particle-beam column comprising a needle-type ions source such as a liquid metal ion source, one or more round lenses, and a plurality of interleaved quadrupole lenses, by means of which the chromatic aberration of the column may be reduced or entirely compensated. Also an ion-beam column comprising a liquid alloy ion source, interleaved quadrupole lenses, and a Wien velocity filter, whereby a focused beam of ions of a single atomic number may be produced. Such columns produce a more finely focused beam than columns based only on electrostatic lenses, and allow increased lens apertures and larger beam currents.

Abstract: An ion implanting apparatus includes a magnetic quadrupole lens disposed between an ion source and an RFQ accelerator. The magnetic quadrupole lens carries out mass spectrometry of an ion beam extracted from the ion source while converging the ion beam, and reduces the divergence of the ion beam due to the space charge effect as compared to an electrostatic quadrupole lens. The use of the magnetic quadrupole lens makes it possible to utilize to a maximum extent the ion beam extracted from the ion source and to restrict to a minimum the reduction in the current of the ion beam during passage of the ion beam, thereby making it possible to generate a high-energy ion beam having a large current on the order of several tens of milliamperes.

Abstract: A charged particle beam exposure method deflects a charged particle beam in a deflection system which includes electromagnetic deflection coils and an electromagnetic lens. The charged particle beam exposure method includes controlling the deflection system based on deflection data, and blocking heat radiation from at least the electromagnetic deflection coils by a partition so as to prevent the heat radiation from reaching the electromagnetic lens and to prevent heat conduction to the electromagnetic lens by the partition.

Abstract: A system for reducing aberration effects in a charged particle beam. The system includes a source of charged particles, such as electrons or ions, and various building blocks for operating on the charged particle beam to generate a desired particle beam pattern. These building blocks can include at least one of a uniform magnetic field component and a uniform electrostatic field component arrangeable in different combinations, enabling coefficients of spherical and chromatic aberration to be canceled out thereby providing a charged particle beam having greatly diminished aberration.

Abstract: A magnetic sector for a non-scanning mass spectrometer includes a high permeability yoke with opposing faces to which are attached high energy product magnets and shaped pole pieces separated by a gap so that a high magnetic flux exists in the gap. The high magnetic flux in the gap enables very small surface areas of the pole pices faces forming the gap so that the overall magetic sector volume and weight are reduced.

Abstract: A compact ion beam injection apparatus for tandem accelerators wherein the outputs from two independent ion sources, that may be operated continuously, can be selectively chosen and mass analyzed so that the output from any one of the sources can be rapidly selected and efficiently directed to the input point of a tandem accelerator.

Abstract: A method of automatically and accurately accomplishing focusing and astigmatism correction in an electron beam apparatus such as a scanning electron microscope. The electron beam is raster scanned to scan a specimen in two dimensions. If the obtained signal intensity distribution curve has only one peak, the peak position P2 of a curve obtained by raster scanning the beam vertically is detected. The peak position P1 of a curve obtained by raster scanning the beam horizontally is detected. An intermediate position P0 is calculated, using the formulaP0=(P1+P2)/2The intensity of excitation of the objective lens is adjusted to this intermediate position P0. In this way, if two peaks cannot be obtained by a horizontal raster scan of the beam, depending on the state of the surface of the specimen, it is possible to accurately bring the beam into focus at the position of the circle of least confusion. After this focusing operation, an automatic astigmatism correction is made.

Abstract: Deflection apparatus is shown for high perveance ion beams, operating at 20 Hz fundamental and substantially higher order harmonics, having a magnetic structure formed of laminations with thickness in range between 0.2 and 1 millimeter. Additionally, a compensator is shown with similar laminated structures with resonant excitation circuit, operating at 20 Hz or higher, in phase locked relationship with the frequency of the previously deflected beam. Furthermore, features are shown which have broader applicability to producing strong magnetic field in magnetic gap. Among the numerous important features shown are special laminated magnetic structures, including different sets of crosswise laminations in which the field in one lamination of one set is distributed into multiplicity of laminations of the other set of coil-form structures, field detection means and feedback control system, cooling plate attached in thermal contact with number of lamination layers.

Abstract: A lens for a charged particle beam comprises first, second, third and fourth quadrupoles, a first aperture electrode placed in front of the first quadrupole, a second aperture electrode placed between the first quadrupole and the second quadrupole, a third aperture electrode placed between the second quadrupole and the third quadrupole, a fourth aperture electrode placed between the third quadrupole and the fourth quadrupole, a fifth aperture electrode placed behind the fourth quadrupole, means for exciting the quadrupoles to cause them to converge the charged beam to a line near the third aperture electrode, and means for applying voltage to excite the first to fifth aperture electrodes and cause them to produce an octupole lens action for correcting aperture aberration.

Abstract: A charged particle beam system utilizes a box-shaped cooling member accommodating the lens in order to cool the particle-optical lenses. The cooling medium is circulated between the wall of the lens and the wall of the cooling member, enabling a high transfer of heat by convection. By using a cooling liquid which is undersaturated for air and which is heated prior to its passage through the cooling duct, accumulation of air due to heating can be prevented in the cooling member.