Global space charge effect in SCALPEL

Mkrtchyan, Masis M.; Munro, Eric; Liddle, J. Alexander; Stanton, Stuart T.; Waskiewicz, W. K.; Farrow, R. C.; Katsap, Victor

doi:10.1016/s0167-9317(00)00319-1

Cited by 4 publications

(3 citation statements)

References 2 publications

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“…Although the topic of stochastic blurring has been addressed in the context of electron lithography [28,29], this effect has not been addressed for imaging with electron pulses.…”

Section: The Imaging Systemmentioning

confidence: 99%

Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

et al. 2007

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Although recent years have seen significant advances in the spatial resolution possible in the transmission electron microscope (TEM), the temporal resolution of most microscopes is limited to video rate at best. This lack of temporal resolution means that our understanding of dynamic processes in materials is extremely limited. High temporal resolution in the TEM can be achieved, however, by replacing the normal thermionic or field emission source with a photoemission source. In this case the temporal resolution is limited only by the ability to create a short pulse of photoexcited electrons in the source, and this can be as short as a few femtoseconds. The operation of the photo-emission source and the control of the subsequent pulse of electrons (containing as many as 5 x 10 7 electrons) create significant challenges for a standard microscope column that is designed to operate with a single electron in the column at any one time. In this paper, the generation and control of electron pulses in the TEM to obtain a temporal resolution <10-6 s will be described and the effect of the pulse duration and current density on the spatial resolution of the instrument will be examined. The potential of these levels of temporal and spatial resolution for the study of dynamic materials processes will also be discussed.

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“…Although the topic of stochastic blurring has been addressed in the context of electron lithography [28,29], this effect has not been addressed for imaging with electron pulses.…”

Section: The Imaging Systemmentioning

confidence: 99%

Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

et al. 2007

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“…Resolution in electron-beam systems is linked to the beam current through the space-charge effect: electron-electron interactions in the beam cause blurring of the image, which increases as the beam current is increased [11,12]. The development of a more sensitive material can therefore be of benefit in two ways: for a fixed beam current the throughput can be increased, or, for a given throughput, the beam current can be decreased and the resolution improved.…”

Section: Sensitivitymentioning

confidence: 99%

Resist Requirements and Limitations for Nanoscale Electron-Beam Patterning

2002

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Electron beam lithography still represents the most effective way to pattern materials at the nanoscale, especially in the case of structures, which are not indefinitely repeating a simple motif. The success of e-beam lithography depends on the availability of suitable resists. There is a substantial variety of resist materials, from PMMA to calixarenes, to choose from to achieve high resolution in electron-beam lithography. However, these materials suffer from the limitation of poor sensitivity and poor contrast.In both direct-write and projection e-beam systems the maximum beam current for a given resolution is limited by space-charge effects. In order to make the most efficient use of the available current, the resist must be as sensitive as possible. This leads, naturally, to the use of chemically amplified (CA) systems. Unfortunately, in the quest for ever smaller feature sizes and higher throughputs, even chemically amplified materials are limited: ultimately, sensitivity and resolution are not independent. Current resists already operate in the regime of < 1 electron/nm 2 . In this situation detailed models are the only way to understand material performance and limits.Resist requirements, including sensitivity, etch selectivity, environmental stability, outgassing, and line-edge roughness as they pertain to, high-voltage (100 kV) direct write and projection electron-beam exposure systems are described. Experimental results obtained on CA resists in the SCALPEL ® exposure system are presented and the fundamental sensitivity limits of CA and conventional materials in terms of shot-noise and resolution limits in terms of electron-beam solid interactions are discussed.

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“…Analytical or semianalytical models have been developed. 13,14 The ultimate goal is to produce analytical models that incorporate both lens and global space-charge aberrations enabling sys- FIG. 4.…”

Section: Modeling Of Space-charge Effectsmentioning

confidence: 99%

Space-charge effects in projection electron-beam lithography: Results from the SCALPEL proof-of-lithography system

Liddle¹,

Blakey²,

Bolan³

et al. 2001

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

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Articles you may be interested inPerformances by the electron optical system of low energy electron beam proximity projection lithography tool with a large scanning field J. Vac. Sci. Technol. B 23, 2754 (2005; 10.1116/1.2062435 Stochastic Coulomb interaction effect in ion-neutralized electron-beam projection opticsElectron optical image correction subsystem in electron beam projection lithography Scaled measurements of global space-charge induced image blur in electron beam projection systemIn projection electron-beam systems resolution and throughput are linked through electron-electron interactions collectively referred to as space-charge effects. Hence, a detailed understanding of these effects is essential to optimizing the lithographic performance of a projection electron-beam lithography system. Although many models have been developed to describe one or more of the various aspects of the Coulomb interactions that occur in the beam, there is minimal experimental data available. We have performed a series of experimental measurements in the scattering with angular limitation projection electron-beam lithography ͑SCALPEL͒ proof-of-lithography system to characterize the space-charge effects for such an optical configuration. The results of those measurements have been compared to a combination of computer simulations and analytical models. The agreement between the models and experiments was good, within the limits of experimental error. We determined the exponent in the dependence of blur on beam current to be 1.029Ϯ0.16 ͑1͒, consistent with more recent models. Additionally, we comment on the use of blur modeling for system optimization.

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Global space charge effect in SCALPEL

Cited by 4 publications

References 2 publications

Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

Resist Requirements and Limitations for Nanoscale Electron-Beam Patterning

Space-charge effects in projection electron-beam lithography: Results from the SCALPEL proof-of-lithography system

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