A method to fabricate nano-scale Cu bond pads for improving bonding quality in 3D integration applications is reported. The effect of Cu bonding quality on inter-level via structural reliability for 3D integration applications is investigated. We developed a Cu nano-scale-height bond pad structure and fabrication process for improved bonding quality by recessing oxides using a combination of SiO2 CMP process and dilute HF wet etching. In addition, in order to achieve improved waferlevel bonding, we introduced a seal design concept that prevents corrosion and provides extra mechanical support. Demonstrations of these concepts and processes provide the feasibility of reliable nano-scale 3D integration applications.
- 3D integration
- Wafer bonding