Zr/V/Fe thick film for vacuum packaging of MEMS

Abstract

An approach to maintain vacuum in microelectromechanical systems (MEMS) by integrating the MEMS fabrication process with getter material preparation is presented in this paper. The coating process for a thick film of getter material on silicon and glass wafers, the two commonly used substrates in MEMS fabrication and package, was investigated in detail. The getter material consists of a powder mixture of zirconium, vanadium and iron, which features high sorption capacity to active gases such as H2, O2, N2, CO and H2O vapour. Various kinds of patterned non-evaporable getter (NEG) thick films with thickness from 50 µm to 400 µm were fabricated to investigate the solutions for different MEMS applications. The activation temperature of the thick NEG films was investigated. Fundamental properties of the NEG films were examined, such as the adhesive strength, higher than 119 N cm−2, of the NEG film to Si substrate and the sorption capacity, 4.68 × 106 Pa l m−2, of the coated getter material. The coating of NEG thick film on the inner surface of MEMS pressure sensor illustrates the applicability of the technique in vacuum maintenance of MEMS devices.