Low-temperature Au/Si wafer bonding

The non-uniformity and anisotropy of Au/Si reaction, which results in the formation of craters at the Au/Si bonding interface, are investigated. The non-uniformity of Au/Si reaction is due to the native oxide on the bare Si surface. A different interfacial morphology of Au/Si bonding is observed and explained by a proposed model. To achieve a uniform bonding interface, a Ti/Au layer is deposited onto the bare Si surface, in which the Ti layer is used to decompose the native oxide during bonding. By the proposed bonding structure, a uniform bonding interface without craters has been achieved.