The Impact of Charging on Low-Energy Electron Beam Lithography

Abstract

A major issue in low voltage lithography is surface charging, which results in beam deflection presented as uneven exposure between adjacent structures. In this study, charge-induced pattern distortions in low-voltage energy beam lithography (LVEBL) were investigated using a silicide direct-write electron beam lithography process. Two methodologies have been proposed to avert charging effects in LVEBL, namely, pattern randomizing and lithography using the crossover voltage. Experimental results demonstrated that these methods are effective in significantly reducing the problems associated with charging. They indicate that charging on a sample is a function of time interval and proximity between line structures. In addition, the optimum time and distance between exposures for no charge-induced pattern distortion were determined. By using the crossover voltage of the material for lithography, charging effect can be significantly minimized.

Charging effect induced by electron beam irradiation: a review

“…When using SEM for characterizing insulating materials some problems may also occur: in addition to the distortions [18][19][20][21][22] and the anomalous white/dark contrast [18,[22][23][24][25][26][27] shown in the secondary electron images, the contrast can vary a lot with the beam energy [28] and even magnification. Other unusual phenomena include EBL pattern distortion [29][30][31] and shift of the secondary electron peak in the energy spectrum [28,32]. In fact, all these unusual phenomena are manifestations of the charging effect, which, in principle, is due directly to the accumulation of an amount of static electric charges in the insulating sample.…”

Simple fabrication of UV nanoimprint templates using critical energy electron beam lithography

“…It should also be noted that E 2 varies as a function of HSQ thickness and the underlying substrate properties. 16,18 If the scattering depth of the specific beam energy is larger than the top layer or the HSQ thickness, the bottom layer material properties need to be considered. The value of E 2 for uncoated quartz itself was 2.0 keV.…”

Ultrafast patterning of nanoparticles by electrostatic lithography

“…18,23 There is also another critical energy E 3 above E 2 when the underlying substrate is semiconducting or conducting. 18,23 There is also another critical energy E 3 above E 2 when the underlying substrate is semiconducting or conducting.…”