Fabrication of high-aspect-ratio arrayed structures using Si electrochemical etching

Hirotaka Sato, Takayuki Homma

    Research output: Contribution to journalArticle

    7 Citations (Scopus)

    Abstract

    This paper reviews microscale processes to fabricate three-dimensional structures, in particular, high-aspect-ratio arrayed structures, using precise electrochemical etching process. Array of sharp micropits were pre-formed on the front side surface of Si wafer and the electrochemical etching was carried out using aqueous HF solution, with the back side illumination to generate holes, which diffused to the edge of the micropits to proceed the dissolution of Si with fluoride species. In order to form high-aspect-ratio pores at selected areas, a shade mask pattern was fabricated on the back side surface to align the illumination to the pre-patterned area on the front side surface. The parameters, such as HF concentration, current density and hole diffusion length, were optimized and uniform array of straight pores was formed into the designed area of Si wafer. Subsequently the surface of the pores was thermally oxidized to form SiO2 layers, and arrayed glass tubes with picoliter volume were fabricated. On the other hand, the pore filling with metal was attempted using electrodeposition to obtain array of the metal needles. For this, the "single batch" process was developed to form the pore array and metal filling with single electrolyte, and array of metal micro needles was successfully formed. These processes demonstrated capability and possibility of the electrochemical processes for microscale fabrication, and further precise processes can be developed using these approaches.

    Original languageEnglish
    Pages (from-to)468-474
    Number of pages7
    JournalScience and Technology of Advanced Materials
    Volume7
    Issue number5
    DOIs
    Publication statusPublished - 2006 Jul

    Fingerprint

    Electrochemical etching
    Aspect ratio
    Metals
    Fabrication
    Needles
    Lighting
    Fluorides
    Electrodeposition
    Electrolytes
    Masks
    Dissolution
    Current density
    Glass

    Keywords

    • Electrochemical etching
    • Electrodeposition
    • High-aspect-ratio microstructure
    • MEMS
    • Micro needle array
    • Micro reactor
    • Micropore array
    • Three-dimensional microstructure

    ASJC Scopus subject areas

    • Materials Science(all)

    Cite this

    Fabrication of high-aspect-ratio arrayed structures using Si electrochemical etching. / Sato, Hirotaka; Homma, Takayuki.

    In: Science and Technology of Advanced Materials, Vol. 7, No. 5, 07.2006, p. 468-474.

    Research output: Contribution to journalArticle

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