Room temperature wafer bonding via polysilazane for vacuum sealing bonding

This paper presents a novel room-temperature wafer bonding method under vacuum using perhydropolysilazane (PHPS) as an adhesion layer. Vacuum wafer bonding is a critical technique for vacuum-sealed electronics packaging, such as MEMS sensors; however, conventional methods typically require high-temperature processes. In this study, we propose and demonstrate a room-temperature wafer bonding approach via PHPS, enabling the formation of a robust SiO2 bonding interface. By utilizing plasma hydrophilic treatment to introduce adsorbed water at the bonding interface, the PHPS layer undergoes conversion to SiO2, even though the bonding is performed under vacuum at room temperature. While analysis of the bonding interface reveals partial desorption of the adsorbed water at the bonding interface due to the vacuum process, the achieved bond strength remains high at 3.98 J/m2. The proposed bonding method offers a promising solution for vacuum sealing applications in electronic packaging.