LOW-TEMPERATURE SILICON WAFER BONDING WITH TITANIUM

摘要

A novel low-temperature wafer bonding and layer transfer method isrnpresented. For the first time to our knowledge, nearly void-free 200 mm silicon (Si) wafer bonding is demonstrated using titanium (Ti) as adhesive. An evaluation matrix includes both a temperature split (from 250℃ to 450℃) and a Ti thickness split (from 10 nm to 500 nm). Enclosed micro-cavities are formed by bonding patterned oxidized wafers to blanket Si wafers. After backside thinning, the initial patterned SiO_2 layer is completely transferred from the donor to the host wafer without peeling or delamination. High-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray (EDX) reveals that the strong bonding is attributed to a thin layer of amorphous TiSi formed at Ti/Si interface.