Self-aligned formation of nano-holes to arrayed micro glass tubes

Hirotaka Sato, Takuya Yamaguchi, Tetsuhiko Isobe, Takayuki Homma*, Shuichi Shoji

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Microreactors and micro-fluidic devices require micro-tube structures to reserve and manipulate extremely small volume of liquid specimen, and nano-hole on the micro-tube is useful for its injection, aspiration and filtration, etc. In the present study, we attempted to develop a precise etching process to form nano-hole to the edge part of the micro glass tube by controlling SiO2 etching conditions with diluted aqueous HF solution. The arrayed micro-glass-tubes were fabricated by electrochemical etching of Si wafer followed by wet-thermal oxidation. The bottoms of arrayed micro-glass-tubes were exposed from Si wafer, which possessed pyramid-shape edges. The etching with optimized concentration of HF formed uniform nano-holes only at every bottom edge, indicating self-alignment of the etching process. The diameter of the nano-holes was controllable in the range of ca. 100-500 nm by adjusting the immersion duration and thickness of the glass tube. Nonlinear diffusion of fluoride species to the bottom edges could be the origin of the self-aligned formation of nano-holes at the bottom edges.

Original languageEnglish
Pages (from-to)200-204
Number of pages5
JournalElectrochimica Acta
Issue number1
Publication statusPublished - 2007 Nov 20


  • Arrayed microstructure
  • Etching
  • Maskless nanofabrication
  • Microreactor
  • Silicon micromachining

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry


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