Micromachined screen printing (MaSPrint) technology for RF MEMS applications

Traditional screen-printing technologies have long been used for manufacturing large volume RF circuits. While being an extremely low cost manufacturing solution, there have been relatively few major advancements. For this reason, the resulting thick-film components are generally restricted to microwave frequencies of operation, due to limitations in manufacturing tolerances. At the same time, surface micromachining technologies have undergone rapid developments, enabling high performance and innovative RF MEMS components to be realized. However, when compared to screen printing, this manufacturing technology is very expensive, even for mass production. This paper will introduce, for the first time, a revolutionary technology for implementing true RF MEMS components using screen printing. The basic concepts will be described, including the use of sacrificial layers and photoimageable pastes. This will be followed by results of the first experimental surface micromachined suspension bridges. Detailed discussions will be given on how the authors propose to overcome limitations with this technology. For example, techniques for compensating shrinkage and large grain boundary sizes with the pastes. Finally, a vision of where MaSPrint technology could lead will be given, in the form of design concepts for low loss transmission lines, RF MEMS switches and variable capacitors, for use in cheap high performance filters and phase shifters for both microwave and millimetre-wave applications.