Enhancement of characteristics of a touch sensor by controlling the multi-layer architecture of a low-cost metal mesh pattern

In this study, the characteristics of a metal mesh touch sensor were enhanced by optimizing the multi-layer architecture of the metal mesh pattern. Low-cost metal such as an aluminum (Al) layer was mainly applied to the architectures for practical applications in touch screen panel (TSP) industries. As well, molybdenum (Mo) was added to the architectures in order to minimize the drawbacks of Al. Three types of Mo/Al, Al/Mo and Mo/Al/Mo layers were fabricated by DC sputtering. The thickness of the Al and Mo layer was optimized at 150 and 30 nm, respectively. Low sheet resistance below 0.27 Ω/□ was achieved with good adhesion on a glass substrate. Especially, in the case of architectures in which the Al layer was covered with an Mo layer, thermal stability and corrosion resistance was enhanced. The change in resistance of the Mo/Al/Mo architecture was less than 0.056 even after heat-treatment at 260°C. By using the optimized layer architecture, the mesh pattern with a 4 μm line width showed good optical transmittance (86.7%) and reflectivity (13.1%) at 550 nm, respectively. Also, a touch sensor fabricated by using the Mo/Al/Mo mesh pattern operated well indicating that the mesh pattern is feasible in a TSP application.