International Business Machines Corporation

Kla Tencor Corporation

Kla-tencor Technologies Corporation

Paul F Petric

Mark Armstrong McCord

Alan D Brodie

Guenther O Langner

James D Rockrohr

Michael Stuart Gordon

Michael S Gordon

Rodney A Kendall

Hans C Pfeiffer

Christopher Frederick Robinson

Werner Stickel

Gabor D Toth

Steven D Golladay

Alexander Jozef Gubbens

Samuel Kay Doran

William A Enichen

Jan A Lauber

Timothy R Groves

Edward Michael James

Allen M Carroll

Henri A Khoury

Keith Standiford

Ye Yang

Mark Lin

Frank Y H Fan

Joseph Maurino

Donald F Haire

Richard D Moore

Michael Madsen

Ross W Thompson

Jason Lim

One embodiment relates to an apparatus for electron beam lithography. The apparatus includes an array of cold cathode electron sources for generating an array of electron beams, and driver circuitry underlying the array of electron sources. The driver circuitry is configured to selectively blank individual electron beams so as to create a patterned array of electron beams. The apparatus further includes an imaging system configured to focus and demagnify the patterned array of electron beams and a movable stage for holding a target substrate. The movable stage is configured to translate the target substrate under the patterned array of electron beams. A computer may be configured to send drive signals to the driver circuitry to cause a pattern to be written onto the target substrate to roll across the array in synchronization with the translation of the target substrate. Other embodiments, aspects and feature are also disclosed.

Apparatus and methods for electron beam lithography using array cathode

One embodiment disclosed relates to an apparatus for reflection electron beam lithography. The apparatus includes an electron source, a patterned electron reflector generator structure, a stage, a demagnifying electron lens, and an ExB separator. The ExB separator configured to bend a trajectory of the electron beam towards the dynamic pattern generator structure. The patterned electron reflector structure is configured to reflect select portions of the electron beam so as to form a patterned electron beam. The ExB separator is further configured to allow the patterned electron beam to pass straight through towards the demagnifying electron lens. The demagnifying electron lens is configured to demagnify the patterned electron beam and project the demagnified patterned electron beam onto the target substrate. The apparatus disclosed herein has a straight projection axis and substantially reduces the electron beam path by a factor of three-to-one (compared to a prior apparatus which uses a magnetic prism).

Reflection electron beam projection lithography using an ExB separator

One embodiment relates to a high-voltage electron gun including an insulator stand-off having a resistive layer. The resistive layer is at least on an interior surface of the insulator stand-off. A cathode holder is coupled to one end of the insulator 115 stand-off, and an anode is coupled to the other end. The resistive layer advantageously increases the surface breakdown field strength for the insulator stand-off and so enables a compact design for the high-voltage electron gun. Other embodiments, aspects and feature are also disclosed.

Compact high-voltage electron gun

An electron microscope assembly suitable for enhancing an image of a lithography tool includes an electron microscope configured for positioning below a lithography stage of an e-beam lithography tool, the lithography stage of the e-beam lithography tool including an aperture for providing the microscope line-of-sight to the lithography optics of the lithography tool, a translation unit configured to selectively translate the microscope along the optical axis of the lithography optics of the lithography tool responsive to a translation control system, the translation unit further configured to position the microscope in an operational state such that the optics of the microscope are positioned proximate to the lithography optics, a docking unit configured to reversibly mechanically couple the microscope with the lithography tool, the microscope configured to magnify a virtual sample plane image generated by the lithography tool.

Electron microscope assembly for viewing the wafer plane image of an electron beam lithography tool

One embodiment relates to an electron-beam apparatus for writing a pattern on a target substrate. The apparatus includes a plurality of arrays of actively-controlled pixel elements at a surface of a reflective electron patterning device. The plurality of arrays of actively-controlled pixel elements are arranged so that there is an area without any actively-controlled pixel elements in a region surrounding an optical axis of the objective lens. The plurality of arrays may be arranged to each lie on a circle centered on the optical axis. Other features, aspects and embodiments are also disclosed.

Quasi-annular reflective electron patterning device

One embodiment relates to an apparatus of a dynamic pattern generator for reflection electron beam lithography. The apparatus includes a plurality of base electrodes in a two-dimensional array, an insulating border surrounding each base electrode so as to electrically isolate the base electrodes from each other; and a sidewall surrounding each base electrode. The sidewall comprises a plurality of stacked electrodes which are separated by insulating layers. In addition, the base electrodes are advantageously shaped so as to be concave. Furthermore, a conformal coating may be advantageously applied over the base electrodes and sidewalls. Another embodiment relates to an apparatus for reflection electron beam lithography. The apparatus includes a shadow mask configured to form an array of incident electron beamlets. The shadow mask comprises an array of holes which correspond one-to-one with an array of pixel pads of an electron reflective patterned structure. Other embodiments, aspects and features are disclosed.

Well-based dynamic pattern generator

An electron beam apparatus is configured for dark field imaging of a substrate surface. Dark field is defined as an operational mode where the image contrast is sensitive to topographical features on the surface. A source generates a primary electron beam, and scan deflectors are configured to deflect the primary electron beam so as to scan the primary electron beam over the substrate surface whereby secondary and/or backscattered electrons are emitted from the substrate surface, said emitted electrons forming a scattered electron beam. A beam separator is configured to separate the scattered electron beam from the primary electron beam. The apparatus includes a cooperative arrangement which includes at least a ring-like element, a first grid, and a second grid. The ring-like element and the first and second grids each comprises conductive material. A segmented detector assembly is positioned to receive the scattered electron beam after the scattered electron beam passes through the cooperative arrangement. Other embodiments, aspects and features are also disclosed. The apparatus is configured to yield good topographical contrast, high signal to noise ratio, and to accommodate a variety of scattered beam properties that result from different primary beam and scan geometry settings.

Apparatus and method for obtaining topographical dark-field images in a scanning electron microscope

One embodiment disclosed relates to a method of setting a surface charge of an area on a substrate to a desired level. The substrate is held on a stage, and a stage bias voltage applied to the stage is controlled. A flood of electrons is directed to the area. The stage bias voltage is controlled such that the surface charge of the area reaches an equilibrium at the desired level. Another embodiment disclosed relates to a method of auto-focusing a main electron beam incident upon an imaging area of a substrate. A monitor electron beam is generated and directed towards a monitoring area of the substrate at a non-perpendicular incidence angle. An in-focus band in data collected from the monitor beam is detected. The focal length of an objective lens focusing the main beam is adjusted based upon a position of the in-focus band.

Apparatus and methods of controlling surface charge and focus

Keyhole shaped slit apertures, sized and oriented to define a desired deflected beam trajectory, such as a planar curvilinear trajectory, are provided for respective deflectors of a charged particle beam system. The beam is statically deflected to a maximum deflection using all deflectors above/prior to a particular slit aperture along the path of the charged particle beam and then scanned in directions orthogonal and parallel to the direction of static deflection while recording current of the charged particle beam intercepted by edges of each slit aperture, in sequence. Correction of deflector alignment and/or driver current (or voltage) is made based on recorded intercepted beam current. The sequence of correction is repeated for calibration, deflection/axis compensation, beam centering and deflection gain and axis compensation parameter adjustment.

Curvilinear axis set-up for charged particle lithography

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)

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 depending on the object size and the distance off the lens symmetry axis. These aberrations are corrected by a set of wire pairs perpendicular to the system axis to add a gradient of the z-component of the magnetic field by which aberrations are generated of the same type but opposite direction as those inherent in the system.

Curvilinear variable axis lens correction with shifted dipoles

A method for improving the alignment of an electron-beam through the optical axis of lenses in a lithographic system is described. The beam is nominally tilted through the center of the lens, and by using a plurality of deflectors the beam is pivoted through the center of the lens using a square wave toggle. The resolution of the beam is measured as it scans over a target, for both toggle states. The nominal tilt angle is chosen such that the resolution is identical for both toggle states. This technique does not rely on using an observation station, as it is common on TEMs, to view a magnified image of the specimen. Therefore, this technique can be used to align a beam that has been shifted off the optical axis, for instance, in a Variable-Axis-Lens lithography (VAL) system.

Method for centering a lens in a charged-particle system

A charged particle beam is controlled by two pairs of deflectors that adjust the beam through two or more deflection centers, thereby saving cost and space and reducing system noise. The mathematics of the superposition of signals and, therefore, of the deflecting fields provide orthogonality of the adjustments so that all adjustments are independent of each other.

Simultaneous deflections in charged-particle beams

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.

Variable curvilinear axis deflection means for particle optical lenses

An electron beam nanometer-level metrology tool includes an ambient temperature electron source and a movable stage for mounting a workpiece. The stage is adapted to position the workpiece's surface in a beam interrogation region. Electrostatic focus lenses convert electrons emitted by the electron source into a beam with a focal point that is positioned in the beam interrogation region. The lenses cause the electron beam to traverse a path that is generally orthogonal to the workpiece surface. Along the beam path are positioned upper and lower electrostatic deflection plates which are connected to an adjustable voltage source that applies ganged, opposite-sense d/c potentials thereto. Those potentials enable a scanning of the beam across the beam interrogation region while the beam remains substantially orthogonal to the workpiece surface, thereby enabling more accurate measurements of surface features. Within the metrology tool, all beam control surfaces are electrostatic so as to minimize power dissipation and temperature differentials.

Growing community of inventors

Brewster, NY, United States of America

Paul F Petric