Yttrium-Aluminum-Garnet Laser Assisted Ink-Jet Printing for Fine Ag Wiring

High throughput fine electrical wiring on the non flat surface is desired for the integration between LSI chips and micro electric components such as MEMS chips, micro actuator devices and micro optical devise in the wide frequency range. Ink-jet printing method is one of the good candidates as a direct writing method on the non flat substrate. However, by conventional ink-jet printing, it is very difficult to realize the fine wiring pattern less than 30μm in these practical conditions. We develop a newly ink-jet printing system assisted by YAG laser to reduce the pattern width and to increase the large transmittance current at high frequency range. At first, we investigated heating effect of a substrate by normal heater for a patterned dot size at the Ag ink droplet diameter of 45μm. As results, a dot diameter decreased from 178μm to 74μm according to increase the substrate temperature from 22 C° to 100 C° . Next the Si substrate was heated by the YAG laser irradiation with consideration of the above experimental results. The Ag wiring was drawn on the Si substrate using a 35μm diameter droplet by an ink-jet system. Therefore the line width was decreased with about 200μm to about 40μm and at the scanning speed 3 mm/s. The wiring width was determined by the balance between the heat supplements by laser irradiation and the volume of ink droplet. In this presentation, electrical properties of ink-jet patterned Ag line with laser irradiation will be reported.