PE-TEOS Wafer Bonding Enhancement at Low Temperature with a High-κ Dielectric Capping Layer of Al2O3

The bond strength of plasma-enhanced tetraethyl-orthosilicate (PE-TEOS) oxide wafers, bonded and annealed at low temperatures (300 degrees C and below), is enhanced by using a thin layer of high-kappa dielectric at the bonding interface. Prior to bonding, a thin (similar to 5 nm) capping layer of Al2O3 high-kappa dielectric was deposited using atomic layer deposition on polished PE-TEOS wafers, followed by surface activation. It was found that after a 300 degrees C anneal in N-2 ambient for 3 h, the bond strength of a wafer pair bonded with Al2O3/PE-TEOS oxide was enhanced by 73.3%. The bonding interface is stable and seamless with no presence of a microvoid. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3507291] All rights reserved.