Electron optical analysis of SCALPEL writing strategy

Zhu, Xiwen; Munro, Eric; Liu, Haoning; Rouse, John A.; Waskiewicz, W. K.

doi:10.1117/12.351092

Cited by 4 publications

(2 citation statements)

References 1 publication

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“…During exposure of the effective field, the stage is scanned mechanically through the beam, which led in the original single beam SCALPEL design to the so-called bow-tie deflection scheme [5]. This meant the beam had to be scanned over a distance equal to twice its diameter in the mechanical scan direction, which is orthogonal to the electronic scan direction.…”

Section: Writing Strategymentioning

confidence: 99%

Design of an electron projection system with slider lenses and multiple beams

Moonen

Leunissen²,

Jager

et al. 2002

Emerging Lithographic Technologies VI

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The commercial applicability of electron beam projection lithography systems may be limited at high resolution because of low throughput. The main limitations to the throughput are:• Beam current. The Coulomb interaction between electrons result in an image blur. Therefore less beam current can be allowed at higher resolution, impacting the illumination time of the wafer. • Exposure field size. Early attempts to improve throughput with "full chip" electron beam projection systems failed, because the systems suffered from large off-axis aberrations of the electron optics, which severely restricted the useful field size. This has impact on the overhead time.A new type of projection optics will be proposed in this paper to overcome both limits. A slider lens is proposed that allows an effective field that is much larger than schemes proposed by SCALPEL and PREVAIL. The full width of the die can be exposed without mechanical scanning by sliding the beam through the slit-like bore of the lens. Locally, at the beam position, a "round"-lens field is created with a combination of a rectangular magnetic field and quadrupoles that are positioned inside the lens. A die can now be exposed during a single mechanical scan as in state-of-the-art light optical tools.The total beam current can be improved without impact on the Coulomb interaction blur by combining several beams in a single lithography system if these beams do not interfere with each other. Several optical layouts have been proposed that combine up to 5 beams in a projection system consisting of a doublet of slider lenses. This type of projection optics has a potential throughput of 50 WPH (300 mm) at 45 nm with a resist sensitivity of 6 µC/cm 2 .

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Section: Writing Strategymentioning

confidence: 99%

Design of an electron projection system with slider lenses and multiple beams

Moonen

Leunissen²,

Jager

et al. 2002

Emerging Lithographic Technologies VI

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show abstract

“…For charged particle optic simulators, Munro and coworkers have published a series of research results, including aberration predictions, 11,12) the design of a photomultiplier, 13) an overview of computational modeling techniques in charged particle optics, 14) and the beam blur of the SCALPEL-HT/Alpha electron beam lithography tool. 15,16) They used FDM and second-order FEM to obtain numerical results under an electrostatic field. However, more accurate results have to be obtained by fitting a Fourier-Bessel series.…”

Section: Introductionmentioning

confidence: 99%

Solution-Refined Method for Electrostatic Potential Distribution of Large-Scale Electron Optics

Lee

Sheu

et al. 2013

Jpn. J. Appl. Phys.

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Starting from the microscopic Smoluchowski equation for interacting Brownian particles under stationary shearing, exact expressions for shear-dependent steady-state averages, correlation and structure functions, and susceptibilities are obtained, which take the form of generalized Green-Kubo relations. They require integration of transient dynamics. Equations of motion with memory effects for transient density fluctuation functions are derived from the same microscopic starting point. We argue that the derived formal expressions provide useful starting points for approximations in order to describe the stationary non-equilibrium state of steadily sheared dense colloidal dispersions.

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Finite element analysis of SCALPEL wafer heating

Kim

Engelstad

Lovell

et al. 1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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A high-throughput scattering with angular limitation projection electron beam lithography ͑SCALPEL͒ tool will typically deliver up to 1.5ϫ10 Ϫ4 J to an area of 250 mϫ250 m over a time of 200 s, corresponding to a power input of 0.75 W. This heat deposition occurs in the upper 60 m of a wafer creating local thermal strain at the time of image formation, and depends on mask and tool conditions and specific boundary conditions. Initial modeling results indicate expansion-induced peak pattern placement errors of ϳ1 nm on a local scale ͑i.e., a 3 mm effective field size͒, several nanometers in a chip area, and a few microns overall. Since the use of a mainly predictive correction algorithm is anticipated, it is vital to conduct a rigorous investigation of the heat transfer and strain formation. Results are presented of such an analysis, illustrating the heating response for the fundamental building blocks of the SCALPEL writing strategy.

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Electron optical analysis of SCALPEL writing strategy

Cited by 4 publications

References 1 publication

Design of an electron projection system with slider lenses and multiple beams

Design of an electron projection system with slider lenses and multiple beams

Solution-Refined Method for Electrostatic Potential Distribution of Large-Scale Electron Optics

Finite element analysis of SCALPEL wafer heating

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