Contactless Component Handling on PCB Using EWOD Principles

As the development of microelectronics is still driving towards further miniaturization, new materials, processes and technologies are crucial for the realization of future cost effective microsystems and components. Futures ICs and passives will also decrease in size, e.g. for RF-ID applications forecast die sizes are smaller than 250 μm, thicknesses less than 50 μm and pitches way below 100 μm. Passives, if not directly integrated into the system carrier, will be even smaller. Touchless and self-assembly based procedures seem to be a promising method for handling miniaturized components not directly fabricated at the very place where they are needed. Based on the "electrowetting on dielectrics" effect (EWOD) - a contactless handling technology well known from lab-on-chip applications for liquid transport, sorting, mixing and splitting - is used as a basis for microelectronics assembly purposes on standard printed circuit boards. Handling shall be feasible for miniaturized components as chiplets, smallest SMDs as well as for nano-scaled building blocks. The physical principle is a change in the droplet contact angle of a droplet when immersed into an electrical field, an effect that can be used for droplet movement and potentially for component transport. The process flow under evaluation starts with positioning of a droplet, containing a component, on a hydrophobic surface of the carrier substrate with rough accuracy. Using the mentioned electro wetting effect the droplet will be moved quickly until the desired position is reached.