抄録
When silver nanoparticles dispersed in organic solvents are metallized by laser irradiation, sintering characteristics have been investigated from the viewpoints of metallography, adhesion strength, and specific resistance. We found that these characteristics depend on laser wavelength to a great extent. An Ar+ laser (488 nm in wavelength) having a high absorption of light in the "Ag ink" promotes sintering from the ink surface, so that the solvents cannot evaporate freely during metallization, and consequently a coarse or porous Ag structure is formed. In contrast, a laser diode with a wavelength of 980 nm produces a denser Ag structure because of a poor absorption, which means that the laser beam is transmitted to the polyimide substrate and table, and then the ink is heated up from the bottom side by thermal conduction. While no peeling occurred at the sintered wire-substrate interface in the bend-peel test, a lower specific resistance of 4.8μΩ・cm was obtained.
