Indium solder printing for low temperature applications and modeling of a droplet generator

In this paper a system for solder printing is presented. With the printing system solder bumps can be directly printed on a substrate. The printhead is actuated by an electro-magnetic working principle. After printing the bumps, flip-chips can be placed and reflow soldered. A model to describe the printhead is presented. A differential equation for the movement of the actuated piston was developed. With the help of the conservation of energy and momentum as well as the continuity condition the droplet velocity and droplet volume can be calculated. The calculated values are compared with experimental data.