International Business Machines Corporation

Nikon Corporation

Nuflare Technology, Inc.

Nuflare Technology America, Inc.

Steven D Golladay

Werner Stickel

Michael S Gordon

Hans C Pfeiffer

Rodney A Kendall

Fritz J Hohn

William Daniel Meisburger

Carl Emil Bohnenkamp

David J Hutson

Juergen Rasch

Munehiro Ogasawara

Kazuhiko Inoue

Paul F Petric

James D Rockrohr

Samuel Kay Doran

William A Enichen

Timothy R Groves

Shinichi Kojima

Chris Robinson

A multiple-electron-beam irradiation apparatus includes a first electrostatic lens, configured using the substrate used as a bias electrode by being applied with a negative potential, a control electrode to which a control potential is applied and a ground electrode to which a ground potential is applied, configured to provide dynamic focusing of the multiple electron beams onto the substrate, in accordance with change of the height position of the surface of the substrate, by generating an electrostatic field, wherein the control electrode is disposed on an upstream side of a maximum magnetic field of the lens magnetic field of the first electromagnetic lens with respect to a direction of a trajectory central axis of the multiple electron beams, and a ground electrode is disposed on an upstream side of the control electrode with respect to the direction of the trajectory central axis.

Multiple electron beam irradiation apparatus, multiple electron beam irradiation method, and multiple electron beam inspection apparatus

The presence of magnetic fields from lenses and other (e.g. parasitic) sources at locations in a charged particle beam system such as the charged particle emitter, where the particles have little or no kinetic energy, creates disturbances of the charged particle trajectories, generating undesired angular momentum and resulting in excessive aberrations and associated adverse effects on system performance. Solutions are provided by suppression of these magnetic fields, by relocating the charged particle emitter away from the field source and/or counterbalancing the field with a bucking field. In addition, residual irrepressible field asymmetries are compensated by a suitable element such as a stigmator located at the correct location in the beam path, permitted by relocation of the charged particle emitter.

High performance source for electron beam projection lithography

An automatic control servo system having a number of cascaded loops equal in number to the number of voltage sources applied to elements of a high-emittance electron source provides accurate and stable electron emission current control independently of beam energy and accommodates large differences in thermal mass between the elements of the electron source, as may be encountered in high-emittance, indirectly heated cathode electron sources. Individual loops of the system may be critically tuned independently of each other.

Servo control for high emittance electron source

A charged particle beam system with a source of charged particles produces a beam directed along a path. A given electromagnetic lens is located along the path. The given electromagnetic lens is adapted to produce a first field directed with a first orientation adapted for affecting a beam of charged particles directed along the path through the lens. A bucking electromagnetic lens is juxtaposed with the given electromagnetic lens adapted to produce a bucking field directed with a bucking orientation adapted for affecting the beam of charged particles directed along the path. The bucking field has an orientation opposing the first field. A fringe field from the bucking electromagnetic lens produces a nulling field to compensate for aberrations and/or beam disturbances.

Image position and lens field control in electron beam systems

An instrument for measurement of illumination intensity distribution of an Electron Beam Projection System (EBPS) comprises a reticle with a clear subfield, a pinhole plate comprising a block of a low atomic number material with a high aspect ratio pinhole therethrough, the pinhole plate being positioned at the image plane of the EBPS. Means is provided for detecting electrons passing through the pinhole, and means is provided for moving, scanning, the pinhole with respect to a fixed electron intensity distribution or scanning the electron intensity distribution with respect to pinhole when held in a fixed position.

Pinhole detector for electron intensity distribution

A method for improving image fidelity on a resist. The method adjusts the intensity distribution of the electron beam such that the feature size at the edges and the center of a subfield have a same width &ldquo;w&rdquo;. This is accomplished by intentionally increasing the incident intensity where the images are small (more pronounced blurring), and intentionally decreasing the incident intensity where the images are large (less pronounced blurring). This can be achieved, for example, by maintaining a cathode temperature profile which increases or decreases radially by an appropriate amount.

Compensation of within-subfield linewidth variation in e-beam projection lithography

A small pinhole aperture and a scintillator are used to observe resolution in a charged particle beam system which is particularly applicable to electron beam projection devices in which the beam is several orders of magnitude larger than the desired resolution and minimum feature size to be produced. A pattern having a feature which is of comparable size to the desired resolution to be observed is scanned across the aperture in two dimensions and a synchronized display of measured light output from the scintillator allows real-time observation of the effects of correction adjustments on the resolution of the system. In this manner, a rough adjustment to near optimum corrections can be obtained over the deflection field in a much reduced number of iterations.

On-line dynamic corrections adjustment method

Variable space charge effects in the imaging portion of a particle beam projection system due to variations in transmitted beam current are compensated with an additional lens appropriately positioned within the imaging system and having a focal length which varies in response to the transmitted beam current.

Compensation of space charge in a particle beam system

A method of optimizing locations of correction elements of a charged particle beam system determines respective corrector element currents to achieve optimum correction as a function of individual corrector location. Substantially complete dynamic correction of FSD and SFD can be obtained consistent with efficiency of operation and minimization of deflection distortion. In particular, FSD and SFD corrections can be sufficiently separated for substantially complete correction of SFD and FSD simultaneously with two stigmators. Both of these types of correction can be provided in complex charged particle beam systems employing curvilinear axis (CVA) particle trajectories and or large area reduction projection optics (LARPO) which cause complex hybrid aberrations in order to achieve high throughput consistent with extremely high resolution supporting one-tenth micron minimum feature size lithography regimes and smaller.

Multi-element deflection aberration correction for electron beam lithography

Direct and indirect electron bombardment provide a sufficiently high degree of temperature uniformity across the emitting surface of a large-area electron source for an electron beam projection system such that a broad beam having illumination uniformity within 1% can be achieved. A diode gun is used to obtain extraction field uniformity and maintain uniformity of illumination. Power requirements and power dissipation in beam periphery truncating apertures is reduced by roughening the surface of a monocrystalline cathode or depositing materials having a higher work function thereon.

High emittance electron source having high illumination uniformity

Numerous largely unpredictable criticalities of operating parameters arise in electron beam projection lithography systems to maintain throughput comparable to optical projection lithography systems as minimum feature size is reduced below one-half micron and resolution requirements are increased. Using an electron beam projection lithography system having a high emittance electron source, variable axis lenses, curvilinear beam trajectory and constant reticle and/or target motion in a dual scanning mode wherein the target and/or wafer is constantly moved orthogonally to the direction of beam scan, high throughput is obtained consistent with 0.1 .mu.m feature size ground rules utilizing a column length of greater than 400 mm, a beam current of between about 4 and 35 .mu.A, a beam energy of between about 75 and 175 kV, a sub-field size between about 0.1 and 0.5 mm at the target at an optical reduction factor between about 3:1 and 5:1, a numerical aperture greater than 2 mrad and preferably between about 3 and 8 mrad and a scan length between about 20 mm and 55 mm. Reticle and target speed preferably differ by about the optical reduction factor.

Electron beam projection lithography system (EBPS)

Resolution of a symmetric magnetic doublet charged particle beam projection lens is improved by applying a non-uniform electrostatic field having the same symmetry conditions as the lens through the magnetic doublet which provides a maximum particle velocity at the plane of symmetry of the magnetic doublet. Since the same symmetry conditions are used for both the electrostatic and magnetic fields, the performance of the magnetic doublet is not compromised. Electrode configurations which provide more intense fields provide further reduction in aberrations for a given potential superimposed on the accelerating voltage.

Magnetic-electrostatic symmetric doublet projection lens

A charged particle beam projection system includes a source of charged particles and a first doublet of condenser lenses with a first symmetry plane through which the beam is directed, located lower on the column. A trim aperture element is located at the first symmetry plane of the first doublet wherein the trim aperture serves as a first blanking aperture. Below the trim aperture there is a shaping aperture. Next is a second doublet of condenser lenses with a second symmetry plane. A third aperture, which is located at the symmetry plane of the second doublet serves as another blanking aperture.

Blanking system for electron beam projection system

An electron beam projection system comprises a source of an electron beam, a first doublet of condenser lenses with a first symmetry plane, a first aperture comprising a trim aperture located at the first symmetry plane of the first doublet also serving as a first blanking aperture. A second aperture comprises a shaping aperture located below the trim aperture. A second doublet of condenser lenses with a second symmetry plane is located below the second aperture, the second doublet having a symmetry plane. A third aperture is located at the symmetry plane of the second doublet wherein the third aperture comprises another blanking aperture. There are first blanking plates between the first condenser lens and the trim aperture, and second electrostatic alignment plates between the trim aperture and the second aperture. The second doublet comprises a pair of illuminator lenses including deflectors coaxial therewith and located inside the radius of the lenses and shielding rings located along the inner surfaces of the lenses, and correctors located coaxial with the deflectors and inside or outside of the radii thereof including stigmators, focus coils and a hexapole.

Illumination deflection system for E-beam projection

An charged particle beam imaging system reduces aberrations affecting resolution at the workpiece where the aberrations are caused by interactions between the charged particles in the beam. The average distance between the particles at a crossover image in the illumination subsystem is increased by positioning an annular aperture at the crossover image.

Growing community of inventors

Hopewell Junction, NY, United States of America

Steven D Golladay