Preparation of a well-defined ammo-terminated self-assembled monolayer and copper microlines on a polyimide substrate covered with an oxide nanoskin

Atsushi Hozumi, Shuichi Asakura, Akio Fuwa, Naoto Shirahata, Tetsuya Kameyama

    Research output: Contribution to journalArticle

    38 Citations (Scopus)

    Abstract

    A well-ordered, uniform amino (NH2)-terminated organosilane self-assembled monolayer (SAM) was prepared on a polyimide (PI) substrate, the surface of which had silica-like reactivity. First, through chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent photooxidation using 172 nm vacuum ultraviolet light, an extremely thin silicon dioxide (SiO2) layer about 1 nm thick, which we call an "oxide nanoskin" (ONS), was prepared on a PI substrate. Due to the presence of this ONS layer, the PI surface's properties became almost identical with those of Si covered with native oxide (SiO2/Si) without any marked change in surface morphology, as evidenced by ζ-potential measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Next, this ONS-covered PI (ONS/ PI) surface was exposed to vapor of a 12.5 vol % solution of N-(6-aminohexyl)(3-aminopropyl)trimethoxysilane (AHAPS) molecules diluted with absolute toluene. On the basis of contact angle analysis, the surface energy of this AHAPS/ONS/PI sample was mostly consistent with that of a SiO 2/Si substrate covered with an AHAPS-SAM (AHAPS/SiO2/Si). On the other hand, the surface energy of an AHAPS-treated PI (AHAPS/ PI) substrate was much smaller than that of the AHAPS/ONS/PI substrate due to insufficient surface coverage by the AHAPS molecules. This was also confirmed by lateral force microscopy using photolithographically micropatterned samples. Fabricated micropatterns composed of AHAPS- and SiO2-covered regions were clearly imaged on the AHAPS/ONS/PI substrate through their difference in friction, while the friction contrast of the micropatterned AHAPS/PI substrate was unclear. This marked difference in packing density of the AHAPS molecules had a direct influence on the adsorption behavior of palladium colloids and subsequent electroless plating of copper (Cu). As confirmed by AFM and XPS, metallization proceeded only on the AHAPS-covered regions, while the SiO 2-covered regions remained free of deposits, resulting in the formation of 10-μm-wide Cu microlines on both samples. However, the plating rate achieved on the AHAPS/ONS/PI substrate was about 4.5 times faster than that on the AHAPS/PI substrate and the pattern resolution was considerably fine.

    Original languageEnglish
    Pages (from-to)8234-8242
    Number of pages9
    JournalLangmuir
    Volume21
    Issue number18
    DOIs
    Publication statusPublished - 2005 Aug 30

    Fingerprint

    Self assembled monolayers
    polyimides
    Polyimides
    Oxides
    Copper
    copper
    preparation
    oxides
    Substrates
    plating
    Interfacial energy
    Silicon Dioxide
    Molecules
    surface energy
    Atomic force microscopy
    friction
    X ray photoelectron spectroscopy
    Silica
    photoelectron spectroscopy
    atomic force microscopy

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Colloid and Surface Chemistry

    Cite this

    Preparation of a well-defined ammo-terminated self-assembled monolayer and copper microlines on a polyimide substrate covered with an oxide nanoskin. / Hozumi, Atsushi; Asakura, Shuichi; Fuwa, Akio; Shirahata, Naoto; Kameyama, Tetsuya.

    In: Langmuir, Vol. 21, No. 18, 30.08.2005, p. 8234-8242.

    Research output: Contribution to journalArticle

    Hozumi, Atsushi ; Asakura, Shuichi ; Fuwa, Akio ; Shirahata, Naoto ; Kameyama, Tetsuya. / Preparation of a well-defined ammo-terminated self-assembled monolayer and copper microlines on a polyimide substrate covered with an oxide nanoskin. In: Langmuir. 2005 ; Vol. 21, No. 18. pp. 8234-8242.
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    abstract = "A well-ordered, uniform amino (NH2)-terminated organosilane self-assembled monolayer (SAM) was prepared on a polyimide (PI) substrate, the surface of which had silica-like reactivity. First, through chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent photooxidation using 172 nm vacuum ultraviolet light, an extremely thin silicon dioxide (SiO2) layer about 1 nm thick, which we call an {"}oxide nanoskin{"} (ONS), was prepared on a PI substrate. Due to the presence of this ONS layer, the PI surface's properties became almost identical with those of Si covered with native oxide (SiO2/Si) without any marked change in surface morphology, as evidenced by ζ-potential measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Next, this ONS-covered PI (ONS/ PI) surface was exposed to vapor of a 12.5 vol {\%} solution of N-(6-aminohexyl)(3-aminopropyl)trimethoxysilane (AHAPS) molecules diluted with absolute toluene. On the basis of contact angle analysis, the surface energy of this AHAPS/ONS/PI sample was mostly consistent with that of a SiO 2/Si substrate covered with an AHAPS-SAM (AHAPS/SiO2/Si). On the other hand, the surface energy of an AHAPS-treated PI (AHAPS/ PI) substrate was much smaller than that of the AHAPS/ONS/PI substrate due to insufficient surface coverage by the AHAPS molecules. This was also confirmed by lateral force microscopy using photolithographically micropatterned samples. Fabricated micropatterns composed of AHAPS- and SiO2-covered regions were clearly imaged on the AHAPS/ONS/PI substrate through their difference in friction, while the friction contrast of the micropatterned AHAPS/PI substrate was unclear. This marked difference in packing density of the AHAPS molecules had a direct influence on the adsorption behavior of palladium colloids and subsequent electroless plating of copper (Cu). As confirmed by AFM and XPS, metallization proceeded only on the AHAPS-covered regions, while the SiO 2-covered regions remained free of deposits, resulting in the formation of 10-μm-wide Cu microlines on both samples. However, the plating rate achieved on the AHAPS/ONS/PI substrate was about 4.5 times faster than that on the AHAPS/PI substrate and the pattern resolution was considerably fine.",
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