Abstract: An electron lens equipped with three magnetic pole pieces defining two gaps forms two magnetic fields. The magnetic fields are generated in said gaps by opposite and same strength excitation. The bore diameters of the middle and lower magnetic pole pieces are equal and the bore diameter of the upper magnetic pole piece is 1.5 to 5 times larger than those of the middle and lower magnetic pole pieces, so that radial (isotropic) distortion is eliminated and spiral (anisotropic) distortion is extremely reduced.

Abstract: A symmetrical magnetic field type objective lens for an electron microscope comprises an upper magnetic pole piece and a lower magnetic pole piece disposed below the upper pole piece with a predetermined inter-pole distance S. Bores of a same diameter b are formed in the upper and the lower pole pieces, respectively. The distance S and the diameter are selected so that 1.ltoreq.S/b.ltoreq.5. Additionally, excitation J of the objective lens is so selected with respect to a predetermined magnetomotive force Jc.o. of a Riecke-Ruska's condenser objective lens that the condition that 1.4 Jc.o..ltoreq.J.ltoreq.1.7 Jc.o. is fulfilled. The objective lens assures a wide field of view without being accompanied with blurs or distortion of image.

Abstract: A triggering device and method for producing nuclear fusion reactions and having two or more intense pulses of high energy electrons derived from a single source and delivered to a target along separate paths but arriving at substantially the same time. The electron beams are produced in the electrode space of an electron accelerator which utilizes a cathode for producing multiple electron beams. Each electron beam is injected into a separate conventional linear pinch discharge. The high energy electron beams follow the pinch discharge and are delivered to the target. The pinch discharge tubes are curved so that each electron beam approaches the target from a different direction for irradiating the target symmetrically. Return conductors strategically located on the outer surface of each pinch discharge tube maintains the curved discharge within the center of the tube and sustains the pinch.

Abstract: In an exemplary embodiment, a command value signal is supplied to a magnetic deflection control loop which operates based on measurement of deflection coil current. A signal proportional to the rate of change of deflection magnetic field is supplied to one input of a differential amplifier, and a signal in accordance with the rate of change of the command value signal is connected with a second input of the differential amplifier. Any error between the rate of change signals as sensed by the differential amplifier is used as an auxiliary control of the deflection magnetic field, whereby eddy current influences are overcome. The system is particularly useful for precision control of an electron beam writer in the manufacture of semiconductor integrated circuits.

Abstract: An electron beam projection system having a projection lens arranged so that upon pre-deflection of the electron beam the electron optical axis of the lens shifts to be coincident with the deflected beam. The projection system includes means for producing an electron beam, means for deflecting the beam, a magnetic projection lens having rotational symmetry for focusing the deflected beam and a pair of magnetic compensation yokes positioned within the bore of the projection lens means. The pair of correction yokes has coil dimensions such that, in combination, they produce a magnetic compensation field proportional to the first derivative of the axial magnetic field strength distribution curve of the projection lens. Upon application of current to the pair of compensation yokes the electron optical axis of the projection lens shifts to the position of the deflected beam so that the electron beam remains coincident with the shifted electron optical axis and lands perpendicular to a target.

Abstract: A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons.

Abstract: A unitary electromagnet having two gaps is provided for the double deflection scanning of a charged particle beam. The unitary electromagnet is configured to permit traverse by said beam through the gaps in a plane defined by the gaps. The depth of the gaps is large as compared to the length to accommodate the scan of the beam. The mode of scanning is determined by the waveform used to energize the windings of the electromagnet and includes axial sweep scanning, off center scanning and split scanning.

Abstract: A chromatically corrected deflecting device for particle-beam equipment, particularly electron-beam equipment, comprises an electric deflecting field and a magnetic deflecting field which are simultaneously employed for the deflection of a beam. The two deflecting fields are normal to each other and are oriented relative to each other in such a manner that the beam deflections due to the associated deflecting fields occur in one and the same plane, i.e. in the plane containing the undeflected beam. The electric deflection is at the same time directed in opposition to the magnetic deflection.

Abstract: An adjustable strength multipole permanent magnet is disclosed that comprises a plurality of axial layers of magnetic material wherein one layer can be angularly displaced with respect to an adjacent layer, each of said axial layers comprising a plurality of segments comprising an oriented, anisotropic,, permanent magnet material arranged in a ring, each segment having a predetermined easy axis orientation that is preferably determined by the formula:.alpha.=2.theta.where .theta. is the angle between the radial symmetry line of a segment and the X-axis and .alpha. is the angle between said radial line and the easy axis of the segment.

Abstract: A magnetic lens, useful as an objective lens in a focused charged particle beam generator, includes means for maintaining a constant thermal power dissipation independent of the field strength produced thereby.

Abstract: An electron lens having very low spherical aberration. The two electrodes of the lens, in the case of an immersion lens, and the outer electrodes in the case of a three electrode lens, have central openings (in the region of the optical axis) covered by a metallic thin foil or a fine mesh metallic screen curved in the general shape of a hyperbola. Equations and procedures are given for determining the exact shape of the curvature. A procedure is also disclosed for forming the metallic foil or screen section of the electrode to the desired shape.

Abstract: An electronic optical objective applicable to electrolithographic devices for microlithography in particular in semiconductor and integrated circuits fabrication. The objective comprises an electromagnetic lens formed by two polepieces, one of which is of soft iron and the other of ferrite, spaced from each other by an airgap. It further comprises two deflectors, one of which is placed in a longitudinal zone of weak magnetic field and the other is placed in a longitudinal zone of strong magnetic field. These two deflectors are identical and offset from each other by a certain angle, for example from 215.degree. to 225.degree..

Abstract: An achromatic magnetic deflection device for deflecting by an angle .phi. between .pi. and 2.pi. a beam of charged accelerated particles having different momentum. This device comprises an electromagnet provided with pole pieces delimiting three contiguous sectors, the whole of these sectors, having an axis of symmetry XX, presenting flat input E and output S faces and common faces F.sub.1 and F.sub.2 in an arc of a circle, the position, the radius of curvature of these faces F.sub.1, F.sub.2 as well as the value of the magnetic induction in the sectors being chosen so that the different paths are substantially orthogonal both to faces F.sub.1, F.sub.2 and to axis XX.

Abstract: In an electron-beam probe instrument such as a scanning electron microscope in which the electron gun employs a field-emission cathode the condenser lens is of the `snorkel` design. The term `snorkel` is used to denote a single-pole magnetic lens in which the pole-piece has an axially extending nose portion. The lens is positioned so that the cathode region is immersed in the radial field at the nose of the lens. Preferably the lens is placed closely behind the cathode but outside the vacuum envelope.

Abstract: Magnetic system making it possible to obtain from a pulsed electron beam supplying bunches of electrons of density d.sub.o, a pulsed beam formed from electron groups of density k d.sub.o, said result being obtained by converting the variation of the momentum of the electrons emitted during the time .DELTA. t of the pulse into a length variation of the paths of said electrons, resulting in regrouping or rearrangement of the electrons within the bunch. This magnetic system has at least one electromagnet equipped with several pairs of pole pieces A, B, D defining a succession of air gaps in which are created, by means of at least one annular coil disposed therein, magnetic fields of different values.

Abstract: A switchable auxiliary lens is arranged in the vicinity of the objective lens of an electron microscope to enable switching between TEM mode and STEM mode. The auxiliary lens may be formed by an interruption in the magnetic circuit of one of the poles of the main lens, and may include an electromagnetic coil which can be excited in a reversable manner.

Abstract: Strong focus space charge lens wherein a combination of current-carrying coils and charged electrodes form crossed magnetic and electric fields to focus charged particle beams.

Abstract: A toroidal magnetic deflection coil for an electron beam lithography system which is compensated for deflection placement errors that normally result from eddy currents generated within the coil windings by deflection current inputs to the coil. The compensation is achieved through addition of passive conductive material along the outer periphery of the coil. The conductive material or layer is arranged close to the outer arms of the toroidal coil windings, and thereby compensates the eddy currents within the deflection coils generated by the deflection currents in the inner arms. The compensating material can be utilized to compensate for beam drag which results from the driving circuit settling time and the inductive or capacitive coupling as well, by adding more material of appropriate dimensions.

Abstract: An electron-optical lens arrangement for electron beam apparatus having a static and a dynamic focussing lens system, in which the dynamic focussing lens system is situated inside the static focussing lens system.

Abstract: In a scanning electron microscope, an objective lens field is generated between a pair of deflecting coils and a specimen by an objective lens having upper and lower magnetic pole pieces. A supplemental magnetic pole piece is installed between said upper and lower magnetic pole pieces so that the half width of the objective lens axial magnetic field distribution is increased and the principal plane of the objective lens is positioned near the lower pole piece. By so doing, the spherical aberration coefficient of the objective lens is reduced and a high resolution scanning image is obtained.

Abstract: A magnetic lens system for corpuscular radiation equipment operating in a vacuum, in particular, an objective lens system for electron microscopes, comprising a superconducting shield housing, in which are arranged, at one end, a single hollow cylindrical superconducting shielding device, wound with a lens coil, and at the other end, in front of the free end face of the shielding device, a vacuum chamber for accommodating an object to be examined, permitting the cavity to be relatively large, and detectors for radiation analysis to be arranged therein so that the lens system is therefore suitable for use in scanning electron microscopes.

Abstract: A corpuscular beam microscope for ring segment focusing is provided with a ondenser and an objective magnetic lens system which is disposed substantially axially symmetrically about the microscope axis for the purpose of generating two field maxima separated by a distance not exceeding five times the arithmetic means of half the half height widths of the component magnetic fields forming the maxima. The provision of such a magnetic lens system facilitates the elimination of aperture aberrations of the first and second order and the elimination of chromatic aberrations of zero order and partly of the first order as well as certain extra-axial defects.

Abstract: In a scanning electron microscope, a circle of least confusion of the electron beam is formed on a specimen without operation of a stigmator, then the circle of least confusion is minimized by a stigmator, thereby enabling lens astigmatism in said microscope to be fully corrected.

Abstract: A magnetic lens arrangement for corpuscular radiation equipment working under a vacuum, in particular an objective lens for high voltage electron microscopes, which permits having objects to be examined disposed in a vacuum chamber at room temperature, is achieved by an arrangement which includes a vacuum chamber having a lens coil winding, a superconductive shielding device which is of cup-shaped design and encloses the winding, two superconductive shielding cylinders disposed one behind the other with mutual spacing enclosed by the winding, with a vacuum chamber for the object to be examined disposed in front of the open side of the shielding device and the first shielding cylinder.

Abstract: A multiple electron lens having two axially spaced polepieces defining a space therebetween. The polepieces each have a plurality of axial through openings aligned coaxially defining electron beam paths. A sole anode plate is disposed axially spaced from the polepieces and has openings aligned with the openings defining the beam paths and equal in number thereto. Each beam path has an auxiliary exciting coil and a corresponding stigmator coaxially arranged with the related beam path within the space defined between the polepieces.

Abstract: Apparatus for irradiating the two opposite faces of a target by means of a scanning beam and comprising a magnetic deflection system formed by an electromagnet provided with two pole pieces disposed downstream of the target to be irradiated, the length of the pole pieces corresponding to the amplitude of the scanning beam in such a way that, if .theta.=.theta..sub.1 +.theta..sub.2 is the total scanning angle, the scanning beam of angle .theta..sub.1 impinges on one face of the target, while the scanning beam of angle .theta..sub.2 =.theta.-.theta..sub.1 is deflected in the magnetic deflection system and irradiates the other face, the polepieces having a face, so-called useful face, facing the other face of the target and comprising several sections with different curvatures for obtaining a reflected beam substantially perpendicular to this other face of the target.

Abstract: A combined fine focusing micro lens array and micro deflector assembly for use in electron beam tubes of the fly's eye type is provided. The assembly comprises a fine focusing micro lens array sub-assembly formed from a plurality of spaced-apart stacked parallel thin planar apertured silicon semiconductor lens plates each having an array of micro lens aperture openings. The lens plates each have highly conductive surfaces and are secured to glass rods for holding the plates in stacked parallel spaced-apart relationship with the apertures axially aligned in parallel. A micro deflector assembly is adjacent to the micro lens array sub-assembly. A micro deflector element axially aligned with each respective fine focusing lens element serves for deflecting an electron beam passing through along orthogonal x-y directional axes of movement normal to the electron beam path.

Abstract: The electron beam exposure system according to this invention has a mask with a pattern cut therein that comprises a plurality of sub-patterns that make up an exposed pattern to be formed on the substrate, a first deflecting means for having electron beams sequentially select sub-patterns in the mask, and a second deflecting means that, in synchronism with said first deflecting means, combines the sub-patterns in said mask irradiated with said electron beams to thereby form a complete image of said exposed pattern on said substrate. The system of this invention further comprises a third deflecting means which uses electron beams having a cross section adequately smaller than each sub-pattern in the mask and which has such electron beams scan the selected sub-patterns in the mask, and a fourth deflecting means for arraying and exposing a plurality of complete images of said exposed pattern on said substrate.

Abstract: A charged particle beam scanning apparatus includes a deflector for a beam of charged particles which includes a magnetic field generator to supply an incoming electron beam with a magnetic field whose intensity grows higher in the opposite direction to that in which the beam is deflected.

Abstract: In a magnetic deflection system for deflecting a beam of charged particles, through a given beam bending angle at least four beam deflecting stations are serially arranged along the beam path for bending the beam through the beam bending angle .PSI.. Each of the beam bending stations includes a magnet for producing a static magnetic field component of a strength and of a shape so that the beam is deflected free of transverse geometric aberrations of second order. The beam deflection system also includes sextupole magnetic field components of such a strength and location so as to eliminate second order chromatic aberrations of the deflected beam without introducing second order geometric aberrations, whereby a magnetic beam deflection system is provided which is free of both transverse chromatic and geometric aberrations of second order.

Abstract: The quadrupole mass spectrometer has four conventional rod-shaped poles symmetrically located about the ion injection axis. Opposite pairs of rods are interconnected and connected to an rf voltage source. A shield having a circular aperture is located at the output end of the rods to assure the stoppage of low mass particles. In addition, a stopping element also preferably circular is located on the axis at the output to assure the stoppage of heavy particles. A pair of grids incorporating the stopping element, are sequentially located at the output, normal to the axis, the first is connected to a dc voltage source to accelerate the remaining particles through the fringing field of the quadrupole and the second is connected to a dc voltage source to subsequently decelerate the particles.

Abstract: Supplies for the objective lens scanning coils and stigmator coils of a scanning electron microscope are arranged for digital control by a small computer which receives a digitized input from an imaging electron collector. For a specimen of suitable structure the computer can be programmed for automatic focusing and astigmatism correction or the operator can intervene to apply a manual correction. Astigmatism is detected by comparing the directional derivatives of intensity for corresponding points in two frames with lens settings above and below focus. By taking the difference between the derivatives for each direction of measurement the effect of structural directional features is eliminated; by summing the differences for all directions a value (S) is obtained which represents the magnitude of astigmatism. The required orientation of the stigmator field can be calculated and the excitation current scanned through a range of values to determine the setting for which S is a minimum.

Abstract: An improved magnetic lens having a long focal length for the optical imaging of a specimen having a large surface area by means of a charged-particle beam. The lens includes a cylindrical coil including at least one winding which is surrounded by a field-carrying metallic shell member fabricated of magnetic material disposed at the radially outer surface of winding.

Abstract: In a scanning electron microscope of the type including a manually controllable stigmator coil system for compensating for beam astigmatism, means are included for providing, simultaneously and in a single image, a mapped display of all possible stigmator correction values as a function of coordinate location in the display. The operator of the microscope, by viewing the mapped display, may readily locate the best-corrected area therein and thereby select the correction values that best achieve astigmatism correction. Means are also included which enable the operator to locate the best-corrected area on the mapped display by movable index markers which automatically couple the proper correction values to the stigmator system. The mapped display also serves as an aid in obtaining optimum beam focus and as an indicator of the condition of the microscope.

Abstract: An electron beam exposure apparatus includes an electron beam emitting system having a means for varying the width of an electron beam. In this apparatus a plurality of identical pattern portions corresponding to a plurality of minimum width scanning lines are scanned one at a time, by an electron beam of a width corresponding to the number of repetitions of the minimum width scanning lines, according to the repetition information of the minimum width scanning lines of the electron beam.

Abstract: A method and apparatus for applying focus correction to an E-beam or charged particle system to compensate for wafer warp and mask tilt. In an electron beam system including a registration system which measures the position of four registration marks with the beam and calculates the apparent magnification error of a given chip, means are also provided for using magnification and rotation error information to calculate a height error factor and to apply a compensating current to a dynamic focusing coil of the electron beam to move the effective beam focal plane to a position which matches the wafer or mask plane at each chip site.

Abstract: A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a .nu./.gamma. of .about. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam.

Abstract: In a scanning charged particle microprobe such as a scanning electron microscope, means for generating an exponentially decaying electrical signal and means for generating a step function signal to be summed and applied to the microprobe to cause it to deflect in a step function compensated for the effects of eddy current induced fields.

Abstract: Various optical devices for use with circular-scanning techniques in computed transaxial tomography are disclosed. In essence such devices produce a rotating dipole field so as simultaneously to provide a circular scan and to focus the charged particle beam on the circular target.

Abstract: An electron beam from an electron gun is made to focus on a first position by a focussing lens system. The focussed beam is then magnified and projected on a screen through a magnification lens system having an objective lens, an intermediate lens and a projection lens.The excitation is so variable that the electron beam may be focussed also on a second position behind the projection lens.A specimen is positioned at the first position for normal electron microscope analysis, while, for a scanning electron microscope analysis, another specimen is put at the second position.

Abstract: A device to effect the programmed tracing of figures which have different shapes comprises two electron-optical systems respectively associated with two diaphragms. The first system forms the image of the first diaphragm at a fixed magnification, on the second diaphragm. The first electrically controlled deflection system makes it possible to displace said image in said plane. A second system forms an image of the thus defined diaphragm, in the object plane. A second deflection system makes it possible to displace said latter image in the object plane.

Abstract: A charged particle beam generating apparatus irradiates an article on all sides thereof by scanning the beam across the article and magnetically curving the beam, when scanned away from the article, to the back side of the article. The magnetic structure provides a magnetic field normal to the scanning direction with a field intensity that is greater near the article than it is further from the article. This results in more nearly uniform irradiation of the entire peripheral surface of the article.

Abstract: An electron beam generator for use in electron beam welding wherein the electron beam passes through at least two electromagnetic beam deflecting systems upstream of the electron lens and which act one after another on the beam to define a fixed nonlinear path for the electron beam from the electron gun towards the welding point on a predetermined welding axis, with the other paths being blocked. The fixed path is such that the portion of the beam leaving the last deflecting system is parallel to the portion of the beam from the gun to the first deflection system, and at least one of the beam deflecting systems is offset with respect to the welding axis. In some arrangements the first and last beam portions are in alignment. The coils of the beam deflecting systems are connected in a circuit for controlling the ratio of currents passing through the coils so that the system as a whole is self-compensating for changes in voltage or beam current.

Abstract: An electron beam image of a microcircuit pattern is projected from an irradiated photocathode window to a resist-coated silicon wafer through two successive lens systems having field-containing regions which communicate through a small aperture in a common pole structure that otherwise shields these regions from each other. The lens region in which the photocathode is located contains electrostatic and magnetic fields for accelerating the electrons and focusing the beam toward a crossover point in the aperture. The region in which the wafer is positioned contains only a magnetic field to correct aberrations of the beam image. The arrangement permits reduction of the image size. Beam registration detectors and deflecting devices are located near the aperture in the common pole structure. Because it is isolated from objects located outside of its own lens region, the electrostatic field is not perturbed by these detecting and deflecting devices or by variations in flatness of the wafer surface.

Abstract: A Wien filter for selecting particles having a given velocity from a beam of charged particles. Such a Wien filter comprises means to maintain an electric field and a magnetic field, which fields extend at right angles to each other and each at right angles to the axis of the particle beam. By providing a gradient in the magnetic field by means of two coils which are present on either side of the said beam and the axes of which are substantially parallel to the electric field and in which the magnetic field strengths produced in the coils are directed substantially opposite to each other, both a focus of the particle beam in a more favorable place is obtained and a stigmatic reproduction is effected so that velocity separation is considerably simplified.

Abstract: A shielded magnetic lens and deflection yoke structure for an electron beam column which minimizes aberrations in the lens system caused by winding asymmetry in the field coil, as well as aberrations due to eddy currents created within the magnetic circuit of the lens by interaction with the field of the deflection yoke. The shield includes a polepiece structure for the magnetic electron lens generally comprising a hollow cylinder formed of a plurality of precisely machined magnetic discs stacked concentrically with precisely machined nonmagnetic discs in alternating sequence with the lens coil positioned adjacent the periphery of the cylinder and the deflection yoke positioned within the cylinder or proximate to either end thereof. In one preferred embodiment of the invention the magnetic discs are formed of a nonconductive material such as ferrite and the nonmagnetic discs are formed of alumina.

Abstract: An electron lens system comprising a plurality of quadrupole elements, a plurality of octupole elements for correcting the spherical aberrations of said plurality of quadrupole elements, and an axially symmetric lens, arranged at the inlet or outlet side of said quadrupole and octupole elements for varying the focal length of said lens system so that the excitation currents of said plurality of quadrupole elements remain fixed.

Abstract: A double-focussing mass spectrometer having an electrostatic field energy alyser followed by a magnetic field momentum analyser. The entrance diaphragm is essentially annular and thus the entrance aperture of the spectrometer defines a hollow cone with its apex at the ion source. The number of ions received per second by such an aperture is significantly larger than for a conventional spectrometer entrance aperture.

Abstract: For dark-field imaging of the specimen, a scanning corpuscular-beam micrope is equipped with multiple annular apertures located between the beam source and the specimen on the one hand and between the specimen and the detector on the other hand. The areas of the multiple annular apertures conjointly i.e. complementarily cover the ray path. The aperture situated in front of the detector is surrounded by a wide, radiation-transmitting region. The invention affords utilizing for the generation of the image not only the rays scattered outside of the aperture cone but also a large part of the rays scattered within this cone.