Au-electrode-embedded cyclo-olefin polymer microchip using low-temperature direct bonding

A simple fabrication method of Au-electrode-embedded cyclo-olefin polymer (COP) microchip was developed using hot embossing, Au wet etching and low-temperature direct bonding methods. A prototype microchip (dimension: 20 × 40 mm²) was fabricated. The Au electrode coated by electron-beam evaporation was successfully patterned on COP surface without any intermediate metal layers. The adhesion strength between the COP and the Au film was stronger than the strength between quartz and Au, and as same as between Si and Cr. The bond strength between the COP and Au coated on COP plate was strong enough not to leak flow of de-ionized water at the bonded interfaces. Flow behavior of negative-charged fluorescent microbeads indicates that the electrical continuity of Au electrode was kept after the bonding process. This technology is remarkable advantage of integrating electrode in plastic microchips.