Ceramic packages for MEMS

MEMS is a promising technology with the potential for generating significant growth in the fields of opto-electronics, RF-MEMS and medicine over the next 5 years. MEMS devices are very sensitive to mechanical and environmental perturbations; thus, packaging and assembly of devices are critical to their performance and reliability. Presently, much emphasis is placed on the development of MEMS devices without due consideration of next level assembly, however; ceramic-based multi-layer packages provide mechanical, thermal and electrical solutions allowing for the use of conventional alumina, LTCC or AlN as package materials. AlN packages offer high thermal conductivity and a good CTE match to Si whereas LTCC offers high electrical conductivity with tailored dielectric properties, LTCC materials are recommended for high-speed applications because due to their low loss characteristics at high frequencies. Alumina, on the other hand, provides a robust solution for most demanding applications. Among the problems inherent in assembling MEMS devices are their special handling needs, deep cavity bonding, cleanliness and sealing requirements, yet these problems are not without viable solutions such as hermetically sealing ceramic packages. Through the utilization of numerous material systems, ceramic packages have been developed for accelerometers, photonic switches, projection systems and channeled parts. This paper defines MEMS devices and shows the abundant opportunities they provide to customers across various markets. It also identifies issues related to the assembly and packaging of MEMS devices and the numerous technological solutions provided by multi-layer ceramic technology.