LAUSR

Nowadays, wafer bonding is becoming a key enabling technology for three-dimensional (3D) packaging, micro-electro-mechanical systems (MEMS) encapsulation and heterogeneous integration. This paper develops and investigates entire Si wafer bonding based on thin Al and Sn films. 500 nm-thick Al and 500 nm-thick Sn films are sputtered onto silicon wafers. At bonding temperature of 280 °C, the average shear strength of 11 MPa is achieved at bonding time of 1 min. The dependence of shear strength and fracture surface morphology on bonding temperature and bonding time is illustrated. The physical mechanism is proposed. It indicates that high bonding strength can be achieved at appropriate low bonding temperature with proper short bonding time.