Direct Patterning of Conductive Fine Line in Dielectric Layer for Semiconductor Package

Using inkjet printing, fine conductive lines could be obtained through a combination of suitable substrate wettability. we performed study on what surface conditions are necessary to form a well-defined line using MOD ink. We searched for a combination of wettability to achieve the target line width through numerical analysis. Lattice Boltzmann method (LBM) was used for the numerical technique. The behavior of micro droplets moving on the wettability contrast was analyzed. In addition, the evaporation of water droplet is considered in current study. The behavior of the ink droplet was observed according to the contact angle of the substrate and wetting band. Effect of non-uniform wettability also discussed. And finally, based on the information obtained from numerical analysis, we applied it to the experiment to make fine conductive lines. Contact angle of substrate should not be super-oleophobic, where the evaporation effect is small. And if oleophilic, since the overshoot of the droplet width was large, the wettability of the substrate should be moderate. On the other hand, to obtain driving force through oleophilicity, the wetting band must have high oleophilicity. In the experiment, MOD ink was deposited to specimen to make conductive line
$5\mu\mathrm{m}$
and
$8\mu\mathrm{m}$
widths.