In order to maintain high isolation, air tightest, vacuum, special working environment of MEMS chips, it’s needed to use Cap technology, using silicon or glass for graphics and other necessary processes to form a cavity to accommodate the sensitive structure of MEMS device. In the Cap progress, the cap wafer and MEMS wafer are aligned, bonding the wafers permanently, and the vacuum space of mechanical structure is formed to protect the chips from mechanical scratches and high temperature damage.