Applications on MEMS packaging and micro-reactors using wafer-level glass cavities by a low-cost glass blowing method

Micro cavities including channels and bubbles play an important role in micro-reactors, micro total analysis systems (μTAS), analytical and bio-analytical applications, and microelectromechanical systems (MEMS) packaging. Materials including polymers, metals, silicon and glass have been used in fabrication processes of micro cavities. Compared with plastics, glass is inert and has excellent chemical stability towards organic solvents, strong acids. However, glass is notoriously difficult to machine. In this study, we presented a novel blowing process to fabricate wafer-level micro glass cavities including micro-channels and bubbles. At first, cavities were formed by wet etching on the surface of a silicon wafer. Then, the silicon cavities were sealed with a glass wafer by anodic bonding under high pressure. The bonded wafers were then heated up to above the softening point of the glass and baked for several minutes. The gas included in the sealed cavities to foam the softened glass into cylindrical channels or spherical bubbles. Results show that the wafer level micro glass cavities including cylindrical glass channels and spherical glass bubbles with smooth internal surface have been achieved successfully by the this way. The model of preparing micro glass cavities was also discussed. As examples, applications for wafer-level MEMS packaging and micro-reactors using micro glass bubbles and channels prepared by glass blowing methods will also be presented. This blowing method provides a low-cost avenue to prepare micro glass cavities of high quality for applications of micro-reactors, micro total analysis systems (μTAS), analytical and bio-analytical applications, and MEMS packaging.