[10a-W631-1~12] 3.7 Laser processing

[10a-W631-9] Direct writing of Cu mesh electrodes on flexible substrates and fabrication of thermal sensors

〇Mizue Mizoshiri¹, Ha Phuong Nam¹, Yasuaki Ito², Seiichi Hata² (1.Nagaoka Univ. of Tech., 2.Nagoya Univ.)

Keywords:femtosecond laser induced reduction, Cu mesh electrode, flexible substrate

Cu-mesh electrodes were directly written on flexible PDMS substrates in air using femtosecond laser reduction of CuO nanoparticles. An uniform line width of ~20 µm was obtained at defocus position of the laser pulses at ±5 µm by using an objective lens with a low numerical aperture of 0.45. The electrical resistivity of the fabricated mesh electrodes decreased with increasing the scanning pitch of the mesh. It indicates that large scanning pitch was advantageous to reduce the thermal effect around the adjacent lines. The electrical resistivity at scanning pitch of 50 µm was 1.3×10^-5 Ωm. Cu mesh thermal sensors which exhibited thermal coefficient of resistance of +0.004/ºC at 22-55ºC were successfully fabricated.