International Business Machines Corporation

Nikon Corporation

Hans C Pfeiffer

Werner Stickel

Maris A Sturans

Steven D Golladay

Michael S Gordon

Guenther O Langner

Timothy R Groves

Donald E Davis

Edward V Weber

Merlyn H Perkins

Johann Greschner

Thomas Bayer

Klaus Meissner

Paul F Petric

Samuel Kay Doran

Philip M Ryan

Joseph J Senesi

Cecil T Ho

Robert A Simpson

Fritz J Hohn

Ollie C Woodard

Alan V Hall

Karl H Loeffler

Samuel Kalt

Jon Erik Lieberman

Gunther O Langner

A multi-beam e-beam system employs a set of independently controllable (for blanking and deflection) subsystems placed in a solenoid field, each system having a demagnifying lens comprising at least one passive pole piece, so that the final image demagnifies imperfections in the upstream electron beam. Upper and lower sections of the system employ the focusing effect of the solenoid field to form an image at a shaping aperture and a demagnified image of the beam at the shaping aperture on the workpiece. Small focus corrections due to magnetic lens field non-uniformity and/or target height variations, are accomplished with an electrostatic unipotental lens built into the pole pieces and target voltage variations.

Multi-beam hybrid solenoid lens electron beam system

A magnetic lens employs a solenoid field containing a passive pole piece that shapes the solenoid field to create a demagnifying lens that has very low geometrical aberrations by adjusting the field upstream and downstream of the gap between the pole pieces to create a negative term in the formula for spherical aberrations, subtracting a significant amount from the contribution to the aberrations that comes from the field in the gap.

Solenoid electron beam lenses with high demagnification and low aberrations

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 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

A magnetic lens having a lens bore for the passage of a particle beam includes a dynamic focus coil that is positioned outside the lens bore and within the pole piece that shapes the lens field, so that the magnetic flux lines from the dynamic focus coil all end on the pole pieces of the lens and the shape of the lens field between the pole pieces has its magnitude changed by the current passing through the dynamic focus coil, but the field shape is not changed, thus changing the focal plane of the beam without moving the beam transversely with respect to the system axis.

Particle beam system with dynamic focusing

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)

The invention relates to a manufacturing method for a membrane mask suitable for particle beams with mask fields, which are bounded by thin support walls. The deep plasma etching for the formation of the support walls is halted shortly before reaching the membrane and the last .mu.m before the membrane removed by wet-chemical etching. A high etch selectivity can be achieved using an alkaline etching solution. The support walls 1 are turned by 45.degree. to the (110) direction or oriented parallel to the (100) plane, so that the structures restricted by (111) planes are avoided.

Manufacturing method for membrane lithography mask with mask fields

A reticle for an electron beam system for direct writing applications has a base layer that contains a reticle pattern; a set of reinforcing struts connected to the base layer separating the base layer into a set of non-contiguous subfields; in which the pattern is carried by a set of apertures in said base layer; and in which the base thickness is set such that the probability that an electron traversing said base thickness will suffer a collision that removes it from the beam is greater than 90% while the probability that the electron will be absorbed is low; and in which, optionally, selected subfields of the reticle are compensated for errors in the remainder of the system.

Scattering reticle for electron beam systems

An electron beam system for direct writing applications employs an electron gun having a large emitting surface compared to the prior art and a brightness approximately two orders of magnitude less than prior art systems to illuminate an initial aperture uniformly with a slightly diverging beam that passes efficiently through the aperture, 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.7 pixels per subfield with the low aberration feature of the variable axis lens and the ability to tailor location-dependent corrections that are associated with gaussian systems that stitch the image pixel by pixel.

Electron beam lithography system with low brightness

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.7 pixels per subfield with the low aberration feature of the variable axis lens and the ability to tailor location-dependent corrections that are associated with gaussian systems that stitch the image pixel by pixel.

Electron beam lithography system

A three-stage E-beam deflection system employs breaking the entire field to be scanned into clusters and sub-fields. The scanning provided by the first stage of deflection which scans within the entire field is rectilinear and discontinuous with the scan stopping in the center of each of the clusters where an exposure is to be made, and scanning is the same within each cluster from sub-field to sub-field. The scanning within a cluster by the second stage stops in the center of each sub-field where exposure is to be made. The third stage uses high speed electrostatic deflection to provide scanning with a vector scanning mode within the sub-field being scanned.

Tri-deflection electron beam system

A two staqge, electron beam projection system includes a target, a source of an electron beam and means for projecting an electron beam towards the target with its upper surface defining a target plane. A magnetic projection lens has a principal plane and a back focal plane located between said means for projecting and the target. The means for projecting provides an electron beam directed towards the target. First stage means provides deflection of the beam from area to area within a field. Second stage means provides for deflection of the beam for providing deflection of the beam within an area within a field. The beam crossing the back focal plane produces a telecentric condition of the beam in the image plane with the beam substantially normal to the target plane from the principal plane to the target plane. The magnetic projection lens includes a magnetic structure providing for magnetic compensation positioned within the bore of the projection lens, which produces a compensating magnetic field substantially proportional to the first derivative of the axial magnetic projection field. The axial magnetic projection field provides substantially a zero first derivative of the axial magnetic projection field in the vicinity of the target. The projection system projects on the target plane from the projection system as deflected by the upper and lower stages, at all times maintaining the telecentric condition of the electron beam at the target plane throughout the entire range of deflection of the beam, assuring minimum errors due to target height variations.

Telecentric sub-field deflection with vail

An electron beam system and method for testing three dimensional networks of conductors embedded in an insulating material specimen without physical contact to detect open and short circuit conditions. Top to top surface wiring is tested by irradiating the specimen with an electron beam at a first beam potential to charge the specimen while negatively biasing a grid placed above the specimen surface, and then irradiating selected portions of the specimen with an electron beam at a second beam potential to read the charge on selected conductors while applying a zero or a positive bias to the grid. In one embodiment the charge beam is a focused scanning beam and the first beam potential is preferably greater than the second beam potential.

Electron beam contactless testing system with grid bias switching

This system employs writing of lithographic patterns with a shaped electron beam exposure system which minimizes the time wasted by workpiece positional requirements. The writing field contains an array of sub-fields written in a raster sequence. The large width of the writing field provided by the VAIL system reduces the number of mechanical scans required to write the pattern on the workpiece which further reduces the time required for workpiece positioning. When patterns are being superimposed over previously written patterns, registration is employed. This system includes a registration field confined to local areas on the workpiece, which is larger than the writing field, without requiring change in focus and without requiring the mechanical system comprising the X-Y work table to change speed during the registration and reregistration of the various fields on a semiconductor wafer or mask. The registration field can be larger than the writing field is possible because the quality requirements demanded from the shaped electron beam are less for detecting the locations of such registration marks at the various locations on the wafer.

Growing community of inventors

Ridgefield, CT, United States of America

Hans C Pfeiffer