CMP For Direct Wafer Bonding of Hermetically Sealed Cavity Structures

摘要

Direct wafer bonding (DWB) is being increasingly utilized for advanced device and packaging applications, but both surfaces must be extremely smooth to achieve a uniform bond. Chemical mechanical polishing (CMP) is the ideal process for pre-bond surface preparation. This work focused on developing a process sequence for DWB of both patterned and unpatterned substrates as part of a project to develop hermetically sealed cavities. Deep cavities were etched into various substrates and a CMP process was developed to achieve a target surface roughness, Ra, below 1 nm on borofloat 33 glass substrates.