Low Temperature PE-TEOS Oxide Bonding Assisted by a Thin Layer of High-κ Dielectric

Abstract

The bond strength of plasma-enhanced tetraethyl-orthosilicate (PE-TEOS) oxide, bonded and annealed at low temperatures (300°C and below), is enhanced using a thin layer of high-κ dielectric at the bonding interface. Before bonding, various thin ( ~5 nm) capping layers of high-κ dielectrics (Al 2 O 3 , HfO 2 , and TiO 2 ) are deposited separately on polished PE-TEOS wafers, followed by surface activation. After a 300°C anneal in N 2 ambient for 3 h, the bond strength of wafer pairs bonded with PE-TEOS oxide is enhanced by 97.9, 73.3, and 31.0%, respectively, with TiO 2 , Al 2 O 3 , and HfO 2 layers at the interface.