AVS 49th International Symposium
    Surface Science Thursday Sessions
       Session SS-ThM

Paper SS-ThM11
Ion Emission from Ultrathin Resists during Exposure to Metastable Atom Beams

Thursday, November 7, 2002, 11:40 am, Room C-108

Session: Electronic Structure and Stimulated Processes
Presenter: Y. Yamauchi, National Institute for Materials Science, Japan
Authors: Y. Yamauchi, National Institute for Materials Science, Japan
X. Ju, National Institute for Materials Science, Japan
T. Suzuki, National Institute for Materials Science, Japan
M. Kurahashi, National Institute for Materials Science, Japan
Correspondent: Click to Email
The combination of ultrathin resists and slow metastable atom beams has attracted attention because of its potential for downscaling the semiconductor lithography beyond the diffraction limit, proximity effect, or transmission of conventional exposure radiations, i.e., ultraviolet light, electron beam, and soft x-ray. Slow metastable atoms carrying fairly large excitation energy in their electronic system interact only with topmost atoms at surfaces because the kinetic energies of the atoms are so low that they are reflected above surfaces. These extreme surface sensitivity and damage-free feature to under layers are desirable for an exposure radiation in lithography. Since Berggren et al.@footnote 1@ had suggested the atom lithography, several groups have reported their success on pattern transfer employing metastable atom beams for ultrathin resists (self-assembled monolayer (SAM) of alkanethiolate,@footnote 1@ hydrogen passivation on silicon surface@footnote 2@ followed by wet chemical etching. As to the fundamental phenomena of resists caused by the irradiation of metastable atoms, however, are not well understood. Recently metastable-atom-stimulated desorption (MSD) was discovered for water and alkali coadsorbed surfaces.@footnote 3@ We have investigated MSD of positive ions from alkanethiolate-SAMs and from hydrogen-passivated Si(111) surfaces. The MSD data show H@super +@ and CH@sub x@@super +@ desorption from of the alkanethiolate-SAMs and H@super +@ desorption from the hydrogen-passivated Si(111) surfaces, which provide direct evidence for the dissociation of alkanethiolate-SAMs and of silicon hydrides by metastable helium atom beams at the initial stage of the pattern transfer. @FootnoteText@ @footnote 1@ K. K. Berggren, et al., Science 269 (1995) 1255. @footnote 2@ S. B. Hill, et al., Appl. Phys. Lett. 74 (1999) 2239. @footnote 3@ M. Kurahashi and Y. Yamauchi, Phys. Rev. Lett. 84 (2000) 4725; T. Suzuki, et al., Phys. Rev. Lett. 86 (2001) 3654.