Low-temperature silicon wafer bonding based on Ti/Si solid-state amorphization

Abstract

Strong and nearly void-free bonding has been achieved using a low- temperature Ti/Si-based wafer bonding technique. Bare Si wafers are bonded with oxidized Si wafers at temperatures from 300 to 450°C, using ∼30 nm thick Ti as bonding intermediate. High-resolution transmission electron microscopy and electron energy-loss spectrometry elemental mapping indicate that the strong bonding is attributed to a solid-state amorphization between Ti and Si. Ti demonstrates particularly attractive capabilities to overcome kinetic barriers commonly associated with low-temperature silicon wafer bonding. © 2006 American Institute of Physics.