Laser Sintering of Silver Nanomaterial on Polymer Substrates

Abstract

Direct-write lines deposited on polyimide substrates using silver nanoparticle inks were laser-sintered and compared with similar samples sintered on a hot plate. The lines—30- to 60-μm wide, about 2.4 mm long, and less than a micrometer thick—were laser-sintered by scanning the fundamental wavelength of a continuous-wave Nd:YAG laser along the line. Deposited energy was varied by changing the laser power in addition to the scanning speed, and the resulting bulk resistivity was measured to determine the unsintered, transitional, sintered, and peel-off energy per volume of nanoparticle ink ranges. The bulk resistivity reported was comparable to or better than typical screen-printed conductors, and the elemental composition suggested no thermal damage of the substrate.

Low temperature nanoparticle sintering with continuous wave and pulse lasers

“…Some alternative methods for sintering are chemical densification [5], electrical [6], pressure, laser [7][8][9][10] and microwave sintering [11]. It takes a relatively long time to sinter a sheet, typically one to two hours in a convection oven.…”

“…In addition, the wavelength and absorption have an effect on penetration depth. Short pulse duration and selective sintering make it possible to treat only metal areas and produce less heat into the surrounding material [8][9][10]. Short pulse lasers are used typically for micromachining and ablation.…”