Laser printing of passive electrical components

Abstract

Laser Induced Forward Transfer (LIFT) is used as a useful alternative to other ink printing techniques. Printing conductive materials with any geometry as desired gives us a degree of freedom in many fields of needs, such as microelectronics design. In this work silver nanoparticles ink is used and its resistivity is measured. First of all, the adequate scanning speed to get conductive lines must be known. In order to do that, a first printing with several speeds is done. It is observed that if the scanning velocity is fast enough, individual droplets are formed. However, by diminishing the velocity, the droplets get closer and closer until they form a straight line. Moreover, if the speed continues reducing, agglomerated material is formed. Next step is to determine the appropriate energy for printing. In order to get this, several droplets with different energies are printed. It is observed that, as the energy increases, the droplets lose their regular geometry and show as a splash. Furthermore, several lines are printed with different energies and their resistance have been measured, expecting a decreasing linear dependence, as more conductive material is added. Nevertheless, a much more complex dependence is obtained. Finally, once the parameters have been optimized, a fourth and last one printing of a maze pattern with many electrodes is done, with the objective to study the length-resistance dependence. Although a non-uniformity printing effect appears along the sample, the resistance increases linearly with length.