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Thermocompression bonding of conductive polymers for electrical connections in organic electronics

Polymer Journal volume 52, pages 405–412 (2020)Cite this article

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Abstract

The thermocompression bonding of conductive polymer films was investigated to achieve a flexible wiring and packaging technique for organic and flexible electronics. Conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films were successfully bonded together by thermocompression even at rather low temperatures of 50–100 °C, especially through surface activation treatment using ultraviolet light irradiation. After thermocompression, the PEDOT:PSS films maintained their ohmic electrical conductivity even though the adhered interface had a contact resistivity of less than 1.3 Ω cm2. To examine the applications to electrical bonding, PEDOT:PSS patterns were fabricated on polyethylene naphthalate (PEN) substrates, and the bonding force after thermocompression was investigated. The adhesiveness of bonding was highly improved, and the films were strongly adhered at a bonding temperature of ~100 °C, which was lower than the glass transition temperature (Tg: 160 °C) of the PEN substrates. X-ray photoelectron spectroscopy (XPS) analysis of both the PEDOT:PSS and PEN surfaces and the attenuated total reflectance FT-IR (ATR-FT-IR) for the PEN surfaces indicated that the oxidized species of alcohol and carboxylate were generated after the surface activation process. These chemical species can form hydrogen bonds or covalent bonds that provide robust bonding interfaces.

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Acknowledgements

This work was financially supported by the New Energy and Industrial Technology Development Organization (NEDO) and the Japan Science and Technology Agency (JST) as part of the Matching Planner Program.

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  1. Osaka Research Institute of Industrial Science and Technology, 2-7-1 Ayumino, Izumi, Osaka, 594-1157, Japan

    Kazuki Maeda, Masashi Nitani & Mayumi Uno

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  1. Kazuki Maeda
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  2. Masashi Nitani
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  3. Mayumi Uno
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Correspondence to Kazuki Maeda.

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Maeda, K., Nitani, M. & Uno, M. Thermocompression bonding of conductive polymers for electrical connections in organic electronics. Polym J 52, 405–412 (2020). https://doi.org/10.1038/s41428-019-0294-0

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