MEMS packaging issues and materials

Abstract

MEMS, Micro-Electro-Mechanical Systems, is the ultimate enabling technology for integration of almost any phenomena - motion, light, sound chemical detection, radio waves and computation, but on a single chip. New commercial products send and receive light beams, others detect specific molecules and some mimic several senses simultaneously. If the logic device is the brain, MEMS adds the eyes, noise, ears and other sensory input. But MEMS is also control, the hands and fingers since these devices can move their own elements and also nearby objects. The merging of motion, sensing and computation represents a significant new level in technology. But there are major challenges, especially in packaging, and MEMS probably represents the greatest challenge ever for our industry. This paper will review the status of MEMS fabrication, highlight problems and described some of the packaging strategies that are being suggested. Does MEMS and the optical version, MOEMS (add optic to MEMS) require a high quality hermetic seal? Should we remove specific impurities like water vapor and oxygen in situ? Can getters, molecular-specific scavengers, solve some of the hermetic atmosphere problems? Getters can remove microparticles, moisture, oxygen, hydrogen (poison to GaAs) and other contaminants. What about stiction, the plague that is locking up the microworld? Is new zero-level packaging the cost-effective replacement for the traditional hermetic package. These problems, issues and solutions will be discussed.