New Connecting Method between FPC and ITO by Using Non-conducive Film and Plating
Recently, many electronic devices have been downsized and multi-function have been also required. Therefore, many electronic parts should be packed in a limited space. A flexible printed circuit boards (FPC) have been widely used because of their flexibility. Many electronic devices have displays as an interface. Anisotropic conductive films (ACF) are widely used by flat-panel display manufacturers to electrically connected and mechanical bonded FPC on a glass display. In the case of ACF, the electrical connection is obtained by trapping conductive particles between the conductors of flex circuits and Indium Tin Oxide (ITO). Alternatives for ACF are non-conductive films (NCF), which do not contain any conductive particles but it accomplish the same result. The process achieves direct electrical contact between the conductors and glass display in the adhesive without any conductive particles. This non-conductive process is expected to lead to lower material cost and fine pitch applicability. Adhesive used in this work is the blend of thermosetting resin and thermoplastic resin. NCF was fabricated in a dry film with thickness of 15 μm. The test samples consist of polyimide base FPC. NCF was pre-laminated on an ITO then the test samples were thermally bonded on the glass. The bonding temperature and pressure were mainly 190 oC and 6 MPa, respectively. The bonding time was 10 sec. The thermosetting component in the adhesive was cured during the heat press. The contact resistances between ITO and FPC were measured by 4-probe method. On the other hand, Cu wiring on FPC was etched and activated to make electroless Ni-P selectively deposit by using hydrazine and sodium hypophosphite as a reducing agent and Au film was plated on it. This method realizes finer pitch connecting without extraneous deposition.
Yohei Wakuda Ichiro Koiwa Yoshiyuki Okura Koichiro Kawade Hideaki Yasui Hideo Honma
Kanto-gakuin University,Sumitomo 3M Limited;1-50-1,Mutsuurahigashi,Kanazawa-ku,Yokohama-shi,Kanagawa 236-8501,Japan;3-8-8,Minamihashimoto,Sagamihara-shi,Kanagawa 229-1185,Japan
国际会议
上海
英文
2008-03-17（万方平台首次上网日期，不代表论文的发表时间）