<title>Plasma activated wafer bonding for MEMS</title>

Wafer bonding became a key technology in various MEMS devices manufacturing. In this respect, wafer bonding is a very important technology as far as it enables not only 3D structure building but also wafer level packaging. Plasma activated wafer bonding is a surface activation method in which by applying a plasma treatment to the wafers prior to bringing them in contact for bonding, the surface chemistry can be tailored in order to obtain maximum bond strength for low temperature thermal annealing. A major advantage of this process is that it makes possible some bonding applications which are not possible using standard bonding processes due to different materials characteristics (e.g. high thermal mismatch of the two bonding partners, low Tg for polymer bonds, etc.) Plasma activated bonding was successfully applied for different types of materials: silicon, compound semiconductors, oxides and polymers (e.g. PMMA). The present paper presents experimental results demonstrating the benefits of this new technology and shows examples on how plasma activated wafer bonding can be an alternative to standard wafer bonding processes.