Alignment signals from silicon tapered steps for electron beam lithography

Yi Ching Lin, Andrew R. Neureuther, Ilesanmi Adesida

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Monte Carlo simulations based on a continuous slowing-down approximation (CSDA) model have been used along with experiment to study the alignment signals formed by electrons that are backscattered from anisotropically etched bare-silicon tapered step marks. The CSDA model is demonstrated to be useful for the study of electron backscattering, particularly for materials with low atomic number. It is shown that a step angle of 54.7°gives a backscattered electron signal close to the maximum and that universal curves for the effects of step height and beam voltage on contrast and average signal slope can be obtained by normalizing to the Bethe range. Alignment signals in ternary takeoff angles and quadrantal azimuthal angles are studied. The tradeoff in expanded signal-to-noise ratios for various detector angular configurations and for processed signals is examined. The detector scheme using low takeoff angles in the azimuthal quadrant facing the step is found to be the best. Experimental results from an ETEC Autoscan Scanning Electron Microscope (SEM) confirm may theoretically predicted aspects of alignment signals. The crystallographic effect of electron channeling which is not considered in the Monte Carlo simulation is evaluated experimentally.

Original languageEnglish
Pages (from-to)899-911
Number of pages13
JournalJournal of Applied Physics
Volume53
Issue number2
DOIs
Publication statusPublished - 1982
Externally publishedYes

Fingerprint

lithography
alignment
electron beams
silicon
takeoff
electrons
normalizing
quadrants
detectors
tradeoffs
approximation
backscattering
signal to noise ratios
simulation
electron microscopes
slopes
scanning
electric potential
curves
configurations

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Alignment signals from silicon tapered steps for electron beam lithography. / Lin, Yi Ching; Neureuther, Andrew R.; Adesida, Ilesanmi.

In: Journal of Applied Physics, Vol. 53, No. 2, 1982, p. 899-911.

Research output: Contribution to journalArticle

Lin, Yi Ching ; Neureuther, Andrew R. ; Adesida, Ilesanmi. / Alignment signals from silicon tapered steps for electron beam lithography. In: Journal of Applied Physics. 1982 ; Vol. 53, No. 2. pp. 899-911.
@article{321fd46b62ea4b599221b828aeb3ab64,
title = "Alignment signals from silicon tapered steps for electron beam lithography",
abstract = "Monte Carlo simulations based on a continuous slowing-down approximation (CSDA) model have been used along with experiment to study the alignment signals formed by electrons that are backscattered from anisotropically etched bare-silicon tapered step marks. The CSDA model is demonstrated to be useful for the study of electron backscattering, particularly for materials with low atomic number. It is shown that a step angle of 54.7°gives a backscattered electron signal close to the maximum and that universal curves for the effects of step height and beam voltage on contrast and average signal slope can be obtained by normalizing to the Bethe range. Alignment signals in ternary takeoff angles and quadrantal azimuthal angles are studied. The tradeoff in expanded signal-to-noise ratios for various detector angular configurations and for processed signals is examined. The detector scheme using low takeoff angles in the azimuthal quadrant facing the step is found to be the best. Experimental results from an ETEC Autoscan Scanning Electron Microscope (SEM) confirm may theoretically predicted aspects of alignment signals. The crystallographic effect of electron channeling which is not considered in the Monte Carlo simulation is evaluated experimentally.",
author = "Lin, {Yi Ching} and Neureuther, {Andrew R.} and Ilesanmi Adesida",
year = "1982",
doi = "10.1063/1.330558",
language = "English",
volume = "53",
pages = "899--911",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "2",

}

TY - JOUR

T1 - Alignment signals from silicon tapered steps for electron beam lithography

AU - Lin, Yi Ching

AU - Neureuther, Andrew R.

AU - Adesida, Ilesanmi

PY - 1982

Y1 - 1982

N2 - Monte Carlo simulations based on a continuous slowing-down approximation (CSDA) model have been used along with experiment to study the alignment signals formed by electrons that are backscattered from anisotropically etched bare-silicon tapered step marks. The CSDA model is demonstrated to be useful for the study of electron backscattering, particularly for materials with low atomic number. It is shown that a step angle of 54.7°gives a backscattered electron signal close to the maximum and that universal curves for the effects of step height and beam voltage on contrast and average signal slope can be obtained by normalizing to the Bethe range. Alignment signals in ternary takeoff angles and quadrantal azimuthal angles are studied. The tradeoff in expanded signal-to-noise ratios for various detector angular configurations and for processed signals is examined. The detector scheme using low takeoff angles in the azimuthal quadrant facing the step is found to be the best. Experimental results from an ETEC Autoscan Scanning Electron Microscope (SEM) confirm may theoretically predicted aspects of alignment signals. The crystallographic effect of electron channeling which is not considered in the Monte Carlo simulation is evaluated experimentally.

AB - Monte Carlo simulations based on a continuous slowing-down approximation (CSDA) model have been used along with experiment to study the alignment signals formed by electrons that are backscattered from anisotropically etched bare-silicon tapered step marks. The CSDA model is demonstrated to be useful for the study of electron backscattering, particularly for materials with low atomic number. It is shown that a step angle of 54.7°gives a backscattered electron signal close to the maximum and that universal curves for the effects of step height and beam voltage on contrast and average signal slope can be obtained by normalizing to the Bethe range. Alignment signals in ternary takeoff angles and quadrantal azimuthal angles are studied. The tradeoff in expanded signal-to-noise ratios for various detector angular configurations and for processed signals is examined. The detector scheme using low takeoff angles in the azimuthal quadrant facing the step is found to be the best. Experimental results from an ETEC Autoscan Scanning Electron Microscope (SEM) confirm may theoretically predicted aspects of alignment signals. The crystallographic effect of electron channeling which is not considered in the Monte Carlo simulation is evaluated experimentally.

UR - http://www.scopus.com/inward/record.url?scp=0020090664&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0020090664&partnerID=8YFLogxK

U2 - 10.1063/1.330558

DO - 10.1063/1.330558

M3 - Article

AN - SCOPUS:0020090664

VL - 53

SP - 899

EP - 911

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 2

ER -