Photochemically grafted polystyrene layer assisting selective au electrodeposition

Koichi Nagase, Shoichi Kubo, Masaru Nakagawa

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)

    Abstract

    We describe the selective electrodeposition of submicrometer gold (Au) patterns achieved by a thin film resist layer of polystyrene (PS) that was exposed to ultraviolet (UV) light on a photoreactive monolayer of a benzophenone-containing alkylthiol formed on a Au-plated substrate and patterned by thermal nanoimprint lithography. The presence of a PS graft layer caused by the benzophenone monolayer photochemistry at an interface between the PS resist layer and photoreactive monolayer played the important role of suppressing the unfavorable growth of tiny Au grains in regions masked with the PS resist layer, resulting in the selective Au electrodeposition in aperture regions of PS resist patterns. The suppressive effect on selective Au electrodeposition depended on the molecular weight of PS used as a resist material. Among unimodal PSs having weight-average molecular weights (M w's) of 2100, 10 900, and 106 000 g mol -1, the PS of M w = 10900 g mol -1 functioned most effectively as the resist layer. Au electrodeposition at a low current density allowed the preparation of Au lines having widths of submicrometers and a uniform height independent of line widths in resist aperture regions. Submicrometer bump structures of Au lines could be fabricated on transparent silica substrates by the subsequent wet etching of a Au electrode layer and then a chromium adhesive layer.

    Original languageEnglish
    Pages (from-to)11646-11653
    Number of pages8
    JournalLangmuir
    Volume28
    Issue number31
    DOIs
    Publication statusPublished - 2012 Aug 7

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics
    • Surfaces and Interfaces
    • Spectroscopy
    • Electrochemistry

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